Satendra Singh D. Ganeshwar Rao and Manoj Dixit

Today, the transportation sector is mainly dependent on internal combustion engines. The total number of vehicles running on the road has reached 1.2 billion. The transportation sector is responsible for a 23% share of greenhouse gas emissions. As a result, researchers and governments are debating the future of the transportation sector. The main factors driving the discussion and development of alternatives for internal combustion engines are air pollution caused by transportation, energy security concerns, rising hydrocarbon fuel prices, climate change issues, the desire to develop economic infrastructure in rural areas by promoting biofuels and bio-waste management, and the desire to lead the world in new technology development. Currently, four types of configurations are in use: internal combustion engines, battery electric vehicles, fuel cell vehicles, and hybrid vehicles. The major advantages, disadvantages, problems, future, cost, emissions produced, environmental impact, fuel and material availability, efficiency, etc., of all these available options for transportation are presented in this paper. The results of this study show that there are a number of alternatives emerging for transportation, but internal combustion engines will still remain as the primary source for transportation for the coming decades.

]]>Saadalah Akram Saadalah Alghazalah and Sabah Mohammed Jamil Mala Ali

The current study focuses on investigating the mechanical properties of joining two dissimilar pieces of Austenitic stainless steel AISI304 and Low carbon steel ST-37 using rotary friction welding techniques. The metals were welded under different rotational speeds 560,1030 and 1800(RPM) using three forging pressures 45, 65, 80(MPa), under variable friction times at each rotational speed. The tensile test, impact test, microhardness distribution and microstructure examination of the welded specimen were carried out. It was noticed that it is possible to reach the ideal welding parameters with applicable mechanical properties at each rotational speed. The tensile strength increased when the forging pressure increased. The maximum tensile strength was 594(Mpa) achieved at a rotational speed of 560(RPM) with joint efficiency 93.5%. The greatest hardness of the welded parts was achieved in the welding interface of all samples and then gradually decreased towards the adjacent area of the welding zone. The hardness increases with increasing rotational speed, or forging pressure. The impact energy decreased when the forging pressure increased, and the maximum impact of energy value 122(J) were available at rotational speed 1030 (RPM) with joint efficiency 97.6%.

]]>Ezenwa O. N. Obika E. N. Chinweze A. E. and Odeh C. P.

The search for engineering materials for light weight applications, material conservation, and cost effectiveness necessitated the development of new materials. However, the properties of these materials need to be investigated to ascertain its suitability in its application. Hence, the engineering students need to understand the behaviour of these materials and the methods of investigation. This paper presents the development of a piece of simple laboratory equipment for determining the flexural strength of light materials for student practicals. The development process involves the design and construction of the equipment for carrying out 3-point test on a given specimen. The equipment has various components, such as the pivots, force gauge, gauge holder, rack and pinion gear, hand lever and the frame. The graphics design and simulation were done with solidworks software, version 10. The materials used for the production of these components were selected in line with material selection guidelines and also according to the mathematical designed parameters. The selected materials were locally sourced for cost effectiveness. The construction processes involve basic engineering process like cutting, filling, drilling, welding and surface finishing, at the total cost of 125 USD. After construction, the equipment was used to perform a 3-point test on three different materials (Perspex, Plywood and Particle Board), and flexural strengths of 86.3MPa, 26.62MPa and 21.96MPa respectively were obtained. The equipment is recommended for testing a low ductile material requiring a maximum flexural force of 500N and maximum deflection of 0.1m. Hence, it can be used in high colleges for the study of strength of materials.

]]>Massimo Cavacece

Purpose: This research proposes a multi-input multi-output (MIMO) model, based on a data-driven approach, to assess passenger vibration comfort on rail vehicles. The MIMO model represents the mathematical relationship between input and output variables that contains modal properties and vibration transmission. An optimization algorithm estimates the frequency response functions at the interface seat-passenger of the trains. Methods: The MIMO model evaluated the frequency response functions along x-, y- and z- axis. Multivariate analysis considered the calculation of the partial coherence functions, the cross-correlation functions, and the Anderson-Darling nonparametric test. Results: This research considered the acceleration measurements on two Trains, one Tramway, and one Underground. This research developed accelerations analyses in the time domain; the transmissibility of accelerations in the frequency domain. The measuring points were on the seat base and the interface seat-passenger of the trains. The frequency response data, obtained experimentally according to x- y- and z- axis, generated a multi-input and multi-output frequency response model. This research is based on experimental investigations and statistical tests. The calculation of partial coherence evaluated the percentage of spectrum output due to a specific (conditional) input. The partial coherences assess the energy contribution of each input to the output. The cross-correlation test showed the phase between input and output accelerations. The Anderson- Darling test showed the provenance of the data sample from a population with a specific distribution. Anderson-Darling's nonparametric test attaches weight to tails. Conclusions: The seats of the trains were exposed to complex vibrations according to the three directions x, y, and z. The three inputs are linear accelerations along the vertical, lateral, and forward direction of the seat base. If the accelerations on the seat base represented the inputs to the MIMO model, the accelerations acquired at the passenger-seat interface represented the output of the MIMO model.

]]>Zvikomborero Hweju and Khaled Abou-El-Hossein

Grey relational analysis is a widely used approach for the purposes of decision making, prediction and relational investigation. This study utilizes the grey relational analysis for modelling surface roughness during the single point diamond turning of RSA-443. The utilized parameter in this study is the grey relational grade together with cutting speed, feed, and depth of cut. The Taguchi L9 orthogonal array has been utilized for designing the experiment, with three extra experimental runs being carried out for the purposes of validating the developed model. The developed model indicates that the cutting parameters are insignificant as predictors of surface roughness. Grey relational grade is the only significant predictor of surface roughness. Acoustic emission signal root mean square has been used for determining the grey relational grade in the study. The grey relational analysis-based surface roughness values have been compared to experimentally obtained values by using the Mean Absolute Percentage Error (MAPE). The accuracy levels are an exhibition of high prediction power of the model. Pair t-test results indicate the lack of statistical significance in the difference between the experimentally measured and predicted surface roughness values.

]]>Odedeyi Peter Babatunde Abou-El-Hossein Khaled and Abdulkadir Lukman

Machining Rapidly Solidified aluminium (RSA) 6061, a widely used optical material by Ultra-high precision diamond turning, has enabled high accuracy and surface integrity. However, improved quality and productivity require precision surface and machining process monitoring because the duo has a great influence on machine part performance. The study presented in this paper investigates the effects of cutting parameters (i.e., depth of cut, feed rate and cutting speed) on machining output variables (surface roughness and acoustic emission potentials) during ultra-high precision diamond turning of RSA 6061. With the aid of Box-Behnken design (BBD), a response surface methodology, and the analysis of variance (ANOVA), the correlation between cutting parameters and machining output variables were analyzed and modeled. The results showed that both surface roughness and acoustic emission potentials are greatly influenced by feed rate and cutting speed. For a better-quality surface roughness and low acoustic emission during ultra-high precision diamond turning of RSA 6061, high cutting speed and low feed rates are the right combinations and vice versa.

]]>Somnath H. Kadhane and Hemant N. Warhatkar

Computer modeling and numerical simulation has become an efficient diagnostic tool to predict the human body injuries caused due to high speed automotive impacts, blast and ballistic impacts. Soft tissues such as muscles and skin in human body are exposed to varying strain rates under dynamic loadings during impacts. The prediction of impact-induced injuries requires a thorough understanding of mechanical behaviour of soft tissues for computational modeling of human body. In the present study, uniaxial tensile tests were conducted on caprine lower extremity muscles in the strain rate range of (500s^{-1}-3500s^{-1}) using custom-made split Hopkinson pressure bar (SHPB) apparatus. The challenges in the dynamic testing of soft tissues such as measurement of weak transmitted signals, use of viscoelastic pressure bars, tensile loading of specimen and generation of constant strain rate were addressed in dynamic tensile testing of soft tissues using polymeric SHPB. The attenuation and dispersion in waves are corrected using isolated incident bar tests. The stress-strain results were determined from the reconstructed waves for the tests conducted on lower extremity caprine muscles. The muscle specimens were tested along and perpendicular to the fiber direction to study the directional dependency of tissue behaviour. The stress-strain response was found to be non-linear and significant dependant on strain rate when tested along and perpendicular to fiber direction at same strain rates. It is also observed that at the same strain rate, the specimen stress of caprine muscle along the perpendicular fiber direction is higher than that along the fiber direction. The obtained results may further be used to develop finite element human body models and safety systems for human body in high rate scenario.

L. W. Tseng C. H. Chung and W. L. Huang

Machine tools are assembled by thousands of components. The surface between two components is the mating surface. The bolt tightening methods will affect the stress and deformation of mating surface which influences the accuracy and rigidity of machine tools. In the precision machinery industry, if the structure needs to tighten in line such as linear guideway, the senior engineers will tighten the bolts from sides to the middle or middle to sides instead of tightening in order. Furthermore, engineers use two-step of tightening rather than one-step of tightening. Based on their experience, these tightening methods will reduce the stress of mating surface and increase the rigidity of entire structure. In this study, the three bolts tightening model is used to investigate these tightening methods. Three bolts tightening CAD model is created by using the SolidWorks software. The finite element analysis is used the ANSYS workbench R19 software to simulate the bolt tightening methods (tightening sequences and pre-tightening force ratio) on the mating surface and entire model. From the simulation results, the minimum stress is observed in the tightening sequence from sides to middle and maximum stress is obtained in the tightening sequence in order. The experimental results of bolt tightening sequences match the simulation results. The stresses of mating surface and entire model drastically decrease when the tightening step is two-step of tightening. In two-step tightening process, the pre-tightening force ratio 1:1 is the optimal tightening methods for reducing the stress of mating surface compared to another pre-tightening force ratio.

]]>Sujith Bobba Mukkollu Sambasiva Rao B. Harish Babu and Z. Leman

Metal casting is a predominant manufacturing advancement for adeptly fabricating components with complicated shapes. Many of the industrial castings produced are made from steel and iron alloys with attractive properties and less production cost. In this research work, the effect of molybdenum addition to class 30 type grey cast iron for the production of high performance cast iron (HPCI) has been carried out. Molybdenum inclusion not only refines the majority of graphite flakes but also increases the length of a small fraction of graphite flakes and improves the thermal conductivity by a percentage up to 2.2% fixed as per the research conducted, while excessive molybdenum insertion not only induces precipitation and solution reinforcement but it will also enhance the ultimate tensile strength (UTS) and hardness. According to research conducted, it was proved that molybdenum inclusion of 120 gm showed a functional way to spread HPCI with enhancing mechanical and thermal properties in grey cast iron when compared to other percentages of molybdenum used and also the average difference in the percentage of hardness in each type of molybdenum sample is about 5 to 10 %. Finally, after the tests, it was also predicted that the molybdenum's hardenability property was beneficial for white cast iron production which will rise the wear resistance property.

]]>Ernesto Gutierrez-Miravete

This paper describes the determination of optimal replacement age for bearing systems with failure times described by Weibull distributions. Optimal age replacement policies are determined for bearing assemblies produced two different types of steel. The parameters of the Weibull probability distribution functions for the bearings were determined by non-linear least square analysis from published data on rolling contact fatigue lives. The resulting distribution functions are used as inputs into the standard expression for the maintenance cost of an age replacement policy and manipulated symbolically using the computer program Maple. These yields closed form expressions for the policy costs that invariably exhibit the well-known vase shape characteristic of these types of problems. The resulting expressions can then be easily used to determine the optimal replacement age of the bearing components. The problem of determining the optimal age replacement policy of bearing assembles consisting of independent components arranged in series is also examined. The effect on the optimal age replacement time of using the same type steel to manufacture all the components is compared with that of building the bearing assembly using components made with different steels. As expected, the results clearly show the increased superiority of the higher-quality steel components in the form of much longer optimal replacement ages. However, replacement policy efficiencies depend on replacement time in a complex fashion. Moreover, the results also suggest that building bearing assemblies combining high quality and low quality steel components may be wasteful. Overall, computer experimentation and examination of the behavior of cost functions using symbolic manipulation with Maple can produce useful guidelines for the design of optimal age replacement policies.

]]>L. W. Tseng C. Y. Wu H. Y. Tsai C. H. Chung and W. L. Huang

Machine tool is an important role in the industry because the mechanical components or products are manufactured by machine tools. The machine tools are assembled by components. The surface between two components is the combined or contact surface. Different bolt locking sequences will affect the combined surface in the machine tool. In this study, the SolidWorks software is used to create the CAD model. The finite element simulation is used the ANSYS software to simulate the influence of bolt locking methods on the combined surface of column structure and guideway and the fillet radius design on the deformation of anchor bolts. From the simulation results, the minimum deformation of the column is observed in the locking sequence from middle to both sides. The stress distribution of the combined surface is slightly difference of three locking methods. The simulation results of the guideway show that the minimum displacement of combined surface is obtained by using locking sequence from outside to the middle. The maximum displacement is obtained locking sequence from right to the left order. From the simulation results of anchor bolt, increasing the fillet radius of anchor bolt decreases the deformation of anchor bolts. The deformation of anchor bolts drastically decreases with increasing the fillet radius from R8 to R60. The simulation models and results provide the reference for the bolt locking sequence and anchor bolt fillet radius design.

]]>Surajudeen Adewusi

This paper presents the vibration attenuation performance of a double-cantilever dynamic vibration absorber (DCDVA) attached to a simply-supported beam in two different orientations using theoretical and experimental methods. The results showed that the longitudinal configuration of the DCDVA yield better vibration attenuation by absorbing 80% more vibration than the transverse configuration. For the experimental results, the orientation of the DCDVA has very little effect on the resonant frequencies of the combined DCDVA and simply-supported beam system. However the damping of the second resonant frequency is higher for the transverse configuration. The lumped-mass model characterized the frequency response functions of the DCDVA oriented in the transverse direction only, the model could not reproduce the experimental response for the longitudinal orientation of the DCDVA.

]]>Grzegorz Bomba and Piotr Gierlak

This article presents a procedure whose goal was to develop an effective methodology for deploying a 5-axis milling centre in industrial conditions. The method presented in the article, based on the manufacturing of the test piece, aims to reduce the time to deploy a new machine and minimize the effort put in by technological services and maintenance during tests and the process of deploying the machine tool in production. The test piece and its position have been designed in such a way that its manufacture forces the use of complex machine movements in the extreme area of the working space. The paper presents the results of tests involving the machining of a test piece on a CNC machine, measurement of the shape and dimensional characteristics of the object using CMM and analysis of machining accuracy in the context of the use of the machine in the production of aircraft transmission bodies. The material of the test piece is the same as the material of aircraft transmission housings, i.e. aluminum alloy. The universality of presented method is due to the fact that it is independent of the size of the machine's machining space, machine kinematics and also the special functions possessed by the machine; however, it gives a representation of their operation in the form of measuring sheets from the measuring laboratory.

]]>Sinebe J. E. Chukwuneke J. L. and Omenyi S. N.

The understanding of fiber-matrix integrity in fiber-reinforced polymer composites from strain rate sensitivity concept was considered from interfacial energetics point-of-view. The methodology involved the preparation of plantain fibers, treatment of fibers with nine different liquids to render their surfaces hydrophobic, molding of fiber reinforced composites, measurement of contact angles on fibers and composites, composites tensile strength determination, and fiber pullout tests. The results showed that Methyl Ethyl Ketone Peroxide (MEKP) and mercerization (NaOH) rendered the fibers most hydrophobic. MEKP and NaOH treated fibers gave the lowest surface energies, maximum works of adhesion and hence better fiber-matrix bonding (increased fiber-matrix integrity) when compared with other treatments. The strain-rate sensitivity index, m, obtained ranged from 0.2264 for phosphoric acid-treated fiber in the composite to 0.2385 MEKP treatment fiber with an overall average value of m of 0.2341, while the value of m, for untreated fiber reinforced composite was 0.2321. MEKP and NaOH treated fibers were most hydrophobic gave the highest m values and therefore most desired for treatment of fibers for composite formation. The pullout tests result showed that increase in work of adhesion led to an increase in the tensile energy, showing that stronger bonding will guarantee fiber-matrix composite stability and integrity. MEKP and NaOH with maximum free energies of adhesion also exhibit maximum pullout forces which implied that the bonding between fiber and matrix was stronger for these treatments and hence higher fiber-matrix integrity in the composite. It was also shown that the pull-out force increased with the strain rate sensitivity index confirming that one would need composites with higher m-values for stronger fiber/matrix composites. The results of this work are very important in structures that are made with fiber reinforced composite materials, such as, airplane and car bodies. This work shows that the use of the adhesive energy-stress concept to determine the strain rate is valid since the values of strain rate sensitivity indices calculated are comparable with values reported in the literature and that fiber-matrix integrity can be understood from interfacial free energies and strain rate sensitivity concepts.

]]>Fajri Vidian and Deli Huda Putra

Small-Scale engines are very widely used, especially in developing countries like Indonesia. Its use is intended for various daily activities that require small-scale power. The performance small scale engine is very interesting to investigate for suitable in-field applications. In this study, a small-scale engine was investigated to measure torque (T), brake power (BP), brake mean effective pressure (BMEP) using a rope brake dynamometer with configuration of I. The goal of study is to get an influence of the increase of engine speed on torque, brake power, and BMEP. The experiment was done at engine speed in the range of 1400 to 3500 rpm for each load of 3,4, and 5 kg. The results show an increase in engine speed tends to increase the torque, brake power, and BMEP generated for each load used. The maximum of torque, brake power, and BMEP were 4.53 Nm, 1.67 kW, and 349 kPa respectively at 3521 rpm and the load of 5 kg. The result of brake power of the experiment was compared to report at the literature with differences about 2.3%. The value of BMEP was in the range of standard for small scale engines. This result has given a contribution combined influence of speed and load on the T, BP, and BMEP.

]]>Chukwuneke J. L. Umeji A. C. Sinebe J. E. and Fakiyesi O. B.

In this study, investigations were carried out on the energy evaluation, performance analysis and optimization of briquettes produced from biomass wastes (rice-husk and sawdust) and their composites using starch and clay as binders. The proximate compositions of the briquettes were determined following ASTM analytical methods. The moisture content of rice husk and sawdust before briquettes was 20wt.% and 15wt.% respectively. The briquettes produced from bio-waste material of homogeneous particle sizes of 0.5mm and two binders of a percentage of 90:10 which were sun-dried, prepared and moisturized, were reduced to 5wt.% and compressed for the production of briquettes. The energy evaluation of the briquettes was performed using an oxygen bomb calorimeter and the performance test of the briquettes was carried out. Design Expert Central Composite Design Tool was used in the design and Response surface methodology was used to optimize the energy values of rice-husk/sawdust composite briquettes with clay and starch as binders, after which composite briquette made of mahogany sawdust/rice-husk were produced using the optimum condition values of 15% binder starch, 28% rice-husk and 9Mpa compaction pressure. The results showed that composite briquettes of mahogany sawdust and rice-husk produced with starch had a maximum energy value of 5.69kcal/g, while those made with clay had a minimum energy value of 3.35kcal/g. However, the experimental result was less than the predicted optimum value of 2%. This shows that composite briquette made from mahogany sawdust/rice-husk has better energy efficiency than other briquettes considered and it has been observed that starch is a better bonding material than clay. Briquetting technology has great potential to transform waste biomass in affordable, effective and environmentally safe, high-quality solid fuel for households and industry use.

]]>Abdullah S. Albarqi and Alberto Boretti

Our world has witnessed a rapid increase in power generation as a result of the growth of population and economy. Currently, people depend on conventional fuel energy as the main source of power generation; however, conventional fuel is well known for its limitation and impact on the environment. Thus, it was necessary to invest in an alternative source of energy such the solar power. Much research and development for solar power such as Concentrated solar power (CSP) have been implemented around the world, and it shows the capability to compete with conventional fuel technology. This paper aims to study the feasibility of constructing 100 MW CSP Linear Fresnel (LF) solar power in Riyadh, Saudi Arabia. In this study, the National Renewable Energy Laboratory (NREL) System Advisor Model (SAM) was used to design, simulate, and analyze the system. The system was designed based on CSP LF technology with molten salt thermal energy storage (TES), where TES supplies the power cycle with the required thermal energy after sunset. The result has revealed the system's capability to produce a good amount of solar power most of the year, reaching up to 38 GWh during summer. The LF system shows a good capacity factor (CF) exceeding 40%. The study shows that Saudi Arabia is a good place to install the CSP LF solar plant.

]]>Man Djun Lee and Pui San Lee

This study aims to design and develop a size segregation sieve machine that utilizes centrifugal action to separate impurities from short Oil Palm Frond (OPF) fibers. OPF fibers can manufacture into various products such as erosion control mat and medium density fibreboard as an agricultural waste management program for achieving environmental sustainability. In this aspect, the role of the fiber sieving machine would be significant to support the industry in the production of OPF fibers. However, a thorough literature survey reviewed that limited publications are available in this area; most work done is published in the form of patents. In addition, most fiber sieving machines available in the market utilize manual labour work in the separation phase, where they are highly inefficient. Therefore, this study is designed to fill these gaps. The design of this study adopts the mechanism of various size segregation concepts available and includes centrifugal action in the separation process to increase efficiency. Eventually, a prototype was fabricated for laboratory testing. Several vital parameters are highlighted, which includes mesh surface inclination, sieving duration, a rotation speed of screen and maximum capacity that significantly affects the sieving efficiency. Findings from this study show that sieving duration is less significant to the developed design as higher rotation speed will tend to improve the passing percentage of the fibers. Testing results also revealed the potential application of such a machine in other particle separation applications such as soil separation. For future study, it is recommended to improve the current design in terms of parts, size simplification and multiple size segregation adaptation for achieving a higher production rate.

]]>Rizwana Seeni Ibramsa Mohd Juzaila Abd Latif Mohamad Shukri Zakaria Muhamad Noor Harun and Jamaluddin Mahmud

Degeneration and loss of articular cartilage in the synovial joint have been recognized as the main source of osteoarthritis which leads to pain, swelling and limit the joint mobility. Extensive experimental and computational studies have been performed to study the mechanical behavior and characterize the biomechanical properties of articular cartilage. However, a lack of attention was made on the curvature of the cartilage surface by assuming it was a flat surface. This assumption was inappropriate since the synovial joints possessed curved geometrical shape and may contribute to inaccuracies in characterizing the articular cartilage biomechanical properties. This study aims to examine the effects of the curvature of the cartilage surface in finite element modeling which incorporated with the experiment method to characterize biomechanical properties of articular cartilage. In this study, the biomechanical behavior of contact pressure and pore pressure were investigated at different radius of cartilage surface using the finite element method. The cartilage biomechanical properties of elastic modulus and permeability of the bovine humeral head were then characterized using a combination of indentation test and finite element method. It was found that the cartilage curvature produced a 6% difference in contact pressure and a 39% difference in pore pressure distribution compared to the flat surface cartilage in finite element analysis. Furthermore, significant observation in the characterized biomechanical properties was obtained where the differences of the cartilage curvature reached 33% for elastic modulus and 56% for permeability. Based on the results, the surface curvature of articular cartilage could play an important role in the computational modeling and characterization of its biomechanical properties.

]]>Abdullah Alghafis Eihab A Raouf Abdumalik Aldahlawi Faisal Alassaf Abdulmajeed Alrsheedi and Amer Alharbi

Turbochargers is used on several engines since 1962, to gain greater power output. This paper presents a study of the impact of the turbocharger pressure ratio on diesel engine performance and nitrogen oxides (NOX) emissions. A series of simulation experiments were carried out by using Diesel-RK software on variable turbocharger pressure ratio diesel engine. Diesel-RK is known as a very good open source software for youthful researchers, since it is free and talented of simulating combustion and thermodynamics of diesel engines very well. The simulated results showed that, turbocharger pressure ratio (PR) is an important parameter which affects directly on engine performance, engine brake power (BP) increased when pressure ratio increased. At 2500rpm and pressure ratio equal to 1.5 the BP increment about 27.4% when compared to natural aspirated (NA) engine. More increment about 55% is achieved by increasing the pressure ratio to 2.5. Though the specific fuel consumption (SFC) reduced as the pressure ratio increased. At 4000rpm and pressure ratio equal to 1.5 the SFC reduction about 5% when compared to NA engine. More decrement rate in the SFC rate about 7% is achieved by increasing the turbocharger pressure ratio to 2.5. The brake thermal efficiency (BTE) also increased as the pressure ratio increased, due to increase in power. At NA engine and 3000rpm, the BTE is found to be 32.5%, while at PR = 1.5, the BTE is equal to 33.9% and the BTE at the PR equal to 2.5 is increased to 33.8%. On the other hand engine NOx emissions increased as the pressure ratio increased, at 3000rpm and PR equal to 1.5, the NOX rate increased at a rate of 20% when compared to the emissions of NA engine. NOX emissions continuously increased and reached more than 42% with PR equal to 2.5 when compared to NA engine. Turbocharger gives the small displacement engines much more power relative to their size e.g. PR equal to 2.5, turbochargers run off energy of exhaust gases that is always lost by the NA engines, so the recovery of this energy develops the engine efficiency.

]]>Nhu-Tung Nguyen

In this study, by using Taguchi method, with four controllable factors-three levels (milling type, axial depth of cut, feed rate, and spindle speed), the orthogonal array L27 was used to investigate the effects of milling type and cutting conditions on the surface roughness. By analysis of variance (ANOVA), the influences degree of milling type, axial cutting depth, feed rate, and spindle speed on the surface roughness were 9.26 %, 12.85 %, 12.69 %, and 63.08 %, respectively. The interaction factors of these factors that have a quite small influence on the surface roughness. The surface roughness was modeled as a quadratic regression with the confidence level is more than 99.82%. This model was successfully verified by comparison of experimental and predicted results. The optimization process of surface roughness was performed by both Taguchi method and the ANOVA analysis with the same results. The optimum value of surface roughness was 0.374 µm that was obtained in the half up milling, at a cutting depth of 0.4 mm, a feed rate of 480 mm/min, and a spindle speed of 5000 rpm.

]]>A. Zenani T. C. Dzogbewu W. B. Du Preez and I. Yadroitsev

Titanium aluminides have become the preferred titanium-based alloys for high temperature applications due to their resistance to oxidation at elevated temperatures. However, the inherent limitations of the conventional methods of manufacturing have adverse effects on the mechanical properties of the alloy and limit its applications. The current study focused on determining the optimum process parameters that could be used to produce a Ti6Al alloy with required microstructural properties and complex geometrical configurations using the direct metal laser sintering method. Single tracks were produced at laser powers of 150 W and 350 W over a wide range of scanning speeds. Continuous tracks were achieved only at a laser power of 150 W at corresponding scanning speeds of 1.0 m/s to 1.4 m/s. A cross sectional analysis was conducted on the single tracks and 1.2 m/s emerged as the optimum scanning speed. 3D objects were manufactured at optimum process parameters of 150 W, 1.2 m/s and a hatch distance of 80 µm. The microstructure of the 3D objects was homogenous which attests that the direct metal laser sintering method could be used to produce Ti6Al parts with the desired mechanical properties and geometrical complexity.

]]>Pantira Klankaew Kaboon Thongtha Siripawn H Winter Pornchai Chaisanit Kanchana Kumnungkit and Nopparat Pochai

Oil skimmer is a useful tool in recovering all types of floating waste oils, greases and fats from water surfaces. Lubricant film flow velocity approximation is an important problem of oil skimmer belt speed adjustment. The adjustment belt speed level is up to several physical parameters of oil types. A thin lubricant film flow velocity on a moving belt oil skimmer can be modeled in a form of a nonlinear differential equation as a boundary value problem. The model is providing the lubricant film flow velocity in each thickness layers. In this research, a centered in space finite difference method and a Quasi-Newton iterative method are proposed to approximate the solutions of the nonlinear thin lubricant film flow velocity model. Their numerical simulations of a thin lubricant film flow velocity on a moving oil skimmer belt with varied physical parameters are investigated. The proposed numerical techniques give good agreement approximated solutions in several moving belts speed levels with the external force factor. These are then useful to achieve the optimum belt oil skimmer speed for each lubricant type.

]]>Atif Alkhazali Akram Alsukker Morad Etier and Mohammad M. Hamasha

The dielectric permittivity and conductivity of (AgPO_{3})_{1-x}(Ag_{2}SO_{4})_{x} compound was investigated at different concentrations of (Ag_{2}SO_{4}). The effect of concentration on AC conductivity and permittivity as well as temperature and frequency was investigated in order to model this behavior. Multidimensional mathematical models were as proposed to predict the impedance components and the dielectric permittivity components of the glass system as a function of temperatures, frequencies and concentrations. Artificial Neural Network (ANN) and nonlinear regression approaches were set as curve fitting techniques in order to construct models based on 1700 points of data. This model can be then used to predict these proprieties at any concentration and therefore helping the product designer to choose the proper mixing and temperature conditions. For ANN, 20, 50, and 100 nodes in a single hidden layer neural network were considered. Although data results of the two approaches showed a good alignment with experimental data, the ANN model with twenty nodes was able to predict the outputs with lower MSE values range from 0.008 to 0.012 for impedance and from 0.006 to 0.008 for dielectric losses than the regression technique. Moreover, R^{2} values for the neural network were over 99% in both training and testing of impedance and dielectric permittivity while R^{2} values for non-linear regression vary between 73.86% to 94.75%. The proposed ANN model can be of a great help to find the optimal dielectric permittivity and conductivity of (AgPO_{3})_{1-x}(Ag_{2}SO_{4})_{x} compound when dealing with a specific application.

Wawan Rauf Rustan Tarakka Jalaluddin and Muhammad Ihsan

Flow separation is expected to have the effect of increasing aerodynamic drag due to decreased pressure distribution at the rear of the vehicle. The faster the flow separation occurs, the lower the pressure distribution is in the area, thereby reducing vehicle performance. Therefore, flow modification is needed with expected effects on the separation delay and the reduction in wake and vortex formation. This modification can be done through the application of suction active control in the separation area. The research is intended to analyze the effect of suction active control on flow characteristics, pressure distribution and aerodynamic drag on vehicle models with suction velocity variations. The test model used is an Ahmed model modified by changing the orientation of the flow. The study used a numerical computational approach with a standard k-epsilon turbulence model at 19.4 m/s upstream velocity. Results revealed that the use of flow active control was able to reduce wake and vortex formation through separation delay and to increase the minimum pressure coefficient by 73% on the model with Usc_{2} suction velocity of 0.5 m/s, gaining the highest drag coefficient reduction of 10.897% in the same model.

Nguyen Hong Son and Do Duc Trung

This paper presents the optimization of cutting parameters when surface milling according to the stages of the response surface method. The implemented stages of the response surface method include the screening design, initial experiments and response surface design. The objective of the screening design is to select the input parameters for the next experimental stages. The goal of the initial experiments is to check the choice range of the input parameters ensures that the output function is extreme point or not. The aim of response surface design is to build the relationship between output parameters and the input parameters. The machined material in this study is C45 steel, while the used cutting tool is the face mill with PVD-coated inserts. Accordingly, the optimal values of cutting parameters including cutting speed, feed rate and depth of cut are determined at 230 (m/min), 0.23 (mm/toolpath) and 0.888 (mm), respectively. In case of machining with this cutting parameter, the surface roughness of workpiece reaches the smallest value, only about 0.15 µm.

]]>Nguyen Tuan Anh Hoang Thang Binh and Tran Van Thang

The turning radius of the vehicle is determined based on the coordinates of the center of gravity. When the vehicle is moving at different velocities and driving at different steering angles, the value of the turning radius is also different. This change is nonlinear and continuous and determined by simulation or experimentation process. Previous studies have not established the formula to calculate the value of a turning radius of the vehicle based on input parameters. Therefore, determining the value of a turning radius is complex and time-consuming. This research has shown the dependence between turning radius R on input parameters such as velocity v and steering angle by using a double-track dynamic vehicle model to simulate. Besides, this research also established the state function to calculate the turning radius of the vehicle at different velocities and steering angles. The state function is determined based on the rule of change of the corresponding values. Using only the determined input parameters like velocity and steering angle, the value of the turning radius can be easily calculated with high accuracy through 4 steps. The reference coefficients needed to calculate are also provided in this research. The results of the research can be applied in various computational conditions.

]]>Le Ngoc Truc Nguyen Tuan Nghia Nguyen Trung Thanh Nguyen Minh Thien and Tung Lam Nguyen

Actuator faults of robot manipulators may occur during their lifetime after long time in operation. There are several kinds of actuator failures such as locked joints, free-swinging joints, and loss of actuator torque effectiveness. The main goals of this paper are (i) to classify the loss of torque effectiveness, called torque degradation, into three divergent cases: Boundary Degradation of Torque (BDT), Boundary Degradation of Torque Rate (BDTR), and Proportional Degradation of Torque (PDT); and (ii) to analyze their effect on behavior of a typical industrial robot. The possible failures might degrade the whole system performance or in some certain cases leading to unavoidable damages. In normal operation, we do not have a controller designed specifically for these faults. In order to have a better understanding on how the mentioned problems affect robot operations, with an assumption that the knowledge of robot parameters are known, a closed-loop control law is used to demonstrate the control ability in dealing with these cases. By taking advantage of MATLAB/Simscape Multibody, the quasi-physical model of robot is employed instead of expensive prototypes and experiments. Simulation results show that the joint responses according to different types of failures. In many cases, the robot cannot track the reference trajectories properly.

]]>Abderrahim Razouki Lhoucine Boutahar and Khalid El Bikri

The aim of this work is to study the static bending of functionally graded beams accounting higher order of shear deformation theory. The governing equations, derived from the virtual work principle, are a set of ordinary differential equations describing a static bending of a thick beam. Thus, this paper presents the differential transform method used to solve the previous system of equations. The results obtained lay the foundation to determine the exact analytical solution for different boundary conditions and external loadings. The axial displacement and the bending and shear displacements, in the exact analytical form, of a thick clamped-clamped beam with functionally graded material under a uniform load will be fully developed. Moreover, normal and shear stresses will be analyzed. To confirm the efficiency of this work, a comparison with the numerical results provided by literature is performed. Through this work, the given analytical results provide engineers with an accurate tool to determine the analytical solution for the bending of plates and shells. In addition, the geometric and material parameters that appear clearly in the analytical results allow for a more optimized design of functionally graded material beams. This type of beams is frequently used in mechanical engineering fields such as aerospace engineering.

]]>Quoc Manh Nguyen The-Vinh Do and Thi-Nguyen Nguyen

The heat generated during metal cutting is a major factor affecting the cutting forces, tool life, and chip formation mode. In this research, the Taguchi method was applied to find the optimal values of cutting parameters in hard milling of SKD 61 steel to minimize cutting temperature under cutting oil and Al_{2}O_{3} nanofluid - MQL condition. The effects of cutting parameters including cutting speed, feed rate and depth of cut were investigated by using an L_{9} array of Taguchi method. The signal-to-noise (S/N) ratios and analysis of variance (ANOVA) were applied to analyze the influence of input factors on the cutting temperature. The study result shows that cutting speed is the most influential factor, which gives statistic significant effect on cutting temperature. The speed contributes 52.55 % of total effect under cooling condition of MQL with cutting oil and 53.77 % of total effect under cooling condition of MQL with Al_{2}O_{3} nanofluid. Additionally, the effectiveness in cutting heat reduction of cutting oil - MQL was compared with Al_{2}O_{3} nanofluid - MQL based on experimental measurement of cutting temperature. According to the analysis, the Al_{2}O_{3} nanofluid – MQL is a better option for the cooling conditions during hard milling of SKD 61 steel.

Nguyen Van Thien Do Duc Trung Le Hong Ky and Le Hoang Anh

This paper presents a study of the roughness prediction of the workpiece when using CBN (Cubic Boron Nitride) grinding wheel to process C45 steel on a surface grinder. On the basis of inheriting the previously published studies on modeling surface roughness of workpiece when grinding, this study was conducted to develop one of these models and build a new model of surface roughness that consider many factors affecting surface roughness. Cutting parameters, parameters of grinding wheel, characteristics of materials, characteristics of contact of grinding wheel with workpiece have been included in the roughness model of the surface roughness of workpiece. This new surface roughness model was used to predict surface roughness of workpiece when grinding C45 steel with CBN grinding wheel. The results showed that the surface roughness value when predicting was very suitable for the experiment and the average deviation between the predicted results and the experimental results was only about 9.84%. The surface roughness model proposed in this study also confirms that the roughness can be predicted more accurately than the previous surface roughness models. And then, the development direction for further research is also mentioned in this paper.

]]>Mohammed Abdulqader Sulaiman Ahmed Mohammed Adham and Sirwan Farooq Omar

In this study, nanofluids were used as coolant for high-heat dissipation electronic devices with nanoparticle volume concentrations from 1% to 5%. The results were compared to other conventional cooling systems. Graphite-H_{2}O and CuO-H_{2}O nanofluids were analyzed at inlet velocities of 0.1 m/s and 1.5 m/s in a rectangular copper shaped microchannel heat sink MCHS with a bottom size of 20mm×20mm. The results indicate that suspended nanoparticles significantly increase thermal conductivity, heat flux, pumping power, and pressure drop. For graphite-water and CuO-water nanofluids at 0.1m/s with 5.0% volume, the greatest percentage increase in thermal conductivity was 15.52% and 14.34%, respectively. Graphite-water at 0.1 m/s and 1.5 m/s with 5% volume fraction had a maximum heat flux of 18% and 3.46%, respectively. CuO-water at 0.1 m/s and 1.5 m/s inlet velocity with the same volume concentrations had a heat flux of 17.83% and 3.33%, respectively. For graphite-H_{2}O and CuO-H_{2}O at 0.1 m/s with 5% volume fraction, pumping power and pressure drop were 0.000695 W and 92.63 Pa, respectively. For inlet velocity of 1.5 m/s with same volume concentration were 0.156306 W and 1389.39 Pa, respectively.

P. Vamsi Krishna Amol Balasaheb Jaware and R. R. Srikant

Friction stir welding (FSW) is a solid-state welding process that is gaining importance in recent times due to better control of microstructure. In the present work, a thermo-mechanical model is developed for FSW and under water friction stir welding (UFSW) of AA 6063-T6. Temperature dependent viscosity is considered as thermo physical property along with constant values of thermal conductivity and specific heat. Fine mesh is used for complex parts of tool to obtain good results. Rotational speed of tool, feed rate and plunge pressure are taken as influencing parameters for study. Partial stick-slip boundary condition is taken between the tool and work piece interfaces. Experiments were carried out for validation of model. The results of thermal and material flow histories are extracted. Results shows the significant differences in peak temperature of FSW and UFSW along with reduction in heat affected zone in UFSW whereas results of material flow velocity underlined the differences between the FSW and UFSW in term of peak values of stir velocities with the change in influencing parameters.

]]>Adnan M. Al-sheikh Sirwan K. Jalal and Raed H. Al-Saqa

In the present study, four equations of state (EOSs) were used, namely Birch-Murnaghan, Dodson, Bardeen and modified Lenard Jones for evaluating relative compression volume V_{p}/V_{o}, isothermal bulk modulus B and spinodal pressure P_{sp} for C_{60} under high pressure. Required constant parameters in the EOSs were taken from literature data. Starting from the definition of spinodal pressure, as the pressure at which bulk modulus of a material vanishes (i.e. B=0), A new approach for the evaluation of spinodal pressure have been established, in present work, by extrapolating variation of bulk modulus under high pressure data to the point where B=0, and formulate a new mathematical expression for spinodal pressure. With the aim of finding validity of these equations of state of applying on C_{60}, the calculated results from the entire equations of state are compared with themselves and with other available experimental and theoretical published data. The results for V_{p}/V_{o}, B, and P_{sp} are found to be in agreement with each other for whole pressure ranges. Some other theoretical and empirical data are brought in this study and give good agreements with our results. The new spinodal pressure approach and high pressure studies might represent a promising entrance to the formalism of universal equation of state for solids.

Mochamad Syamsiro Zahrul Mufrodi Ricki Rafly and Syahril Machmud

This study aims to investigate the thermal and catalytic pyrolysis of crushed instant noodle packs (CINP) and crushed coffee sachets (CCS) with and without calcined- natural zeolite catalysts. The experimental works were conducted using a small scale vertical tubular reactor heated by an electrical heater. The thermal pyrolysis experiments were carried out at the reactor temperature of 400, 450, and 500℃. In the second experiments, catalyst was loaded on the upper side of the reactor at various catalyst to plastic ratio. The results show that CINP produced higher liquid product at lower temperature while CCS produced higher liquid product at higher temperature. The maximum liquid oil yield obtained up to 65% on CCS pyrolysis at the temperature of 500℃. The presence of catalyst reduced the liquid fraction for both feedstocks and modified the chemical composition of the pyrolytic oil. The heating value of the pyrolytic oil was high enough for fueling the engine and other external combustion engines. CCS pyrolysis also produced much more solid product compared to CINP.

]]>S. K. Tealib Yehia Abdel-Aziz M. E. Awad Kh. I. Khalil and M. Radwan

The generation of Lorentz force is limited by the local magnetic field and the relative velocity of the spacecraft. As a result of this constraint, the Lorentz force cannot completely take place of the traditional propulsion technologies. In recent years, studying the Lorentz force provided by modulating spacecraft electrostatic charge (magnetic and electric fields) has become a possible good means to control the spacecraft without fuel consumption or reduce the fuel cost. Most of the previous studies concerned the Lorentz force of the magnetic field only. In this paper, we developed a combination of Lorentz forces provided by modulating spacecraft's electrostatic charge (magnetic and electric fields) that can be used to keep the desired relative distances and orientations. We are derived nonlinear dynamic models of satellite relative motion considering J_{2} perturbation, and Lorentz forces to develop a mathematical model for a new technique establishing increase the level of charging in the spacecraft surface. These solutions indicate that the principal effects of the Lorentz force on a spacecraft can be used to correct the drift in the relative position of formation flying due to the effect of Second zonal harmonics, where the magnitude of charge to mass ratio is the key player for the correction of this drift. Numerical results for different examples of formation flying confirmed the capability of Lorentz force to correct the drift in relative position. These corrections depend on the value of charge to mass ratio and magnitude of the relative position.

Do Duc Trung Nguyen Hong Son and Nhu-Tung Nguyen

This paper presents the research carried out to improve machining productivity when conducting external cylindrical grinding of 160Cr12Mo steel on the basis of meeting requirement of surface roughness of workpiece. External cylindrical grinding test of 160Cr12Mo steel was based on the optimal test matrix based on symmetrical D with Al_{2}O_{3} grinding wheel. The test data was analyzed to develop regression function to show the relationship between surface roughness with cutting parameters including cutting velocity, depth of cut and feed rate. Basing on this regression equation, the level of influence of each cutting parameters on surface roughness of workpiece was determined, thereby solutions could be found to improve grinding productivity by increasing the depth of cut but meeting the required roughness value. The test was carried out when it was desirable to improve machining productivity but meeting the machining surface having small roughness. The results showed that it is feasible to increase the depth of cut to increase machining productivity up to 1.8 times while the surface roughness also increases only about 0.6 m.

Nguyen Hong Son Do Duc Trung and Nhu-Tung Nguyen

This paper presents a new approach to improve the machining productivity when grinding the SKD11 steel by using CBN grinding wheel. This approach based on the satisfaction of the surface roughness requirement. The grinding experiments were carried out according to Box-Behnken plan by using the CBN grinding wheel, HY-180x13x31.75-100#. The experimental data was used to build a regression function of the surface roughness depending of the cutting parameters in grinding process including the workpiece velocity, radial feed rate, and depth of cut. The effect degree of each cutting parameter on the surface roughness was also determined. And then, a new solution was proposed to improve the grinding productivity by increasing the workpiece velocity with the satisfaction of the surface roughness requirement. The proposed solution was verified by experimental research. The analyzed results showed that the workpiece velocity can be increased about 1.7 times to increase the machining productivity while the surface roughness only changed about 0.14μm.

]]>Ghandi Rouainia Mounira Rouainia and Abderrezak Metatla

Natural gas distribution providers have periodic and reactive maintenance plans that are not providing enough feedback and data to establish proper predictive analysis for failure, especially on distribution gas regulator station that are regulating gas from transmission pressure to a safe customer distribution pressure, these stations are the only overpressure safeguard and the highest risk at the same time. With the recent advances in computer and telecommunications technologies, some major gas utilities initiated more robust predictive risk analysis plans by introducing SCADA supervisory control and data acquisition to gas distribution, mainly monitoring gas regulator stations and their behavior based on their established overpressure prevention philosophies and long-term predictive analysis goals. This study outlines a full SCADA monitoring solution on a dual run gas distribution regulator station equipped with primary overpressure protection and redundancy options. RTU (Remote Terminal Units) containing flow and pressure monitoring transmitters are installed at specific pressure reduction points in the station piping. Unlike common monitoring practice, we are introducing mid-stream pressure monitoring between the monitor and regular valves, filter differential and flow measurement in our proposed SCADA set up. This system provides real time visibility and data to the gas control room to quickly recognize abnormal or emergency events and assess the current health of regulator equipment. The outlined risk mitigations in this study are created based on identified risks of overpressure under several regulation failure modes of the regulators in standby and working modes. Our SCADA solution introduces means to enhance deductive analysis and predictability for gas control departments and monitoring groups leading to a safer and more reliable gas distribution system, improving emergency response and creating more comprehensive maintenance plans driven by long term predictive risk plans.

]]>Man Djun Lee Ellis Ling Kang Feng and Pui San Lee

This study is about the design and development of seawater pump powered by low height sea wave at near shore region. This study focuses on developing seawater pump that does not use any electricity for delivering high pressure saline water to on shore region which is in line with the global renewable energy quest. Malaysia is blessed with the geographic location of surrounded by sea which enable this technology to be utilized. The challenge in utilizing such technology is due to the nature of the sea wave surrounding Malaysia that is classified as low height sea wave which increase the difficulty in utilizing such technology in neither electricity generation nor sea water delivery. On top of that, there is limited study available in this area especially low wave height. The prototype is designed based on point absorber concept with piston type pump configuration for water delivery. Then the prototype is tested at the Mukah Beach with average recorded wave height of less than 1m. Findings demonstrated that a single prototype pump is capable of delivering maximum pressure head of 10m with maximum flow of 1.2Litre per minute (LPM). For three pumps connected in series, the maximum pressure head can reach up to 25m pressure head with maximum flow rate of 1.5LPM. Similarly, when connected in parallel, the system capable to deliver up to 14m of pressure head and 3LPM of flow rate. The findings indicate that the prototype is significant for seawater delivering. Although the output of the prototype is small, its potential is yet to be fully unleashed. Therefore, it is highly recommended for future study the prototype to be pair together with more similar pumps in series or parallel configurations to form a system of pumps to create higher flow and higher head for more application. This study concludes that the designed and developed prototype is useful for delivering saline water for various application such as seawater desalination or electricity generation in near shore area or islands.

]]>Nuri Kayansayan

The objective of this study is to analyze experimentally and numerically the flow characteristics of a symmetric channel arisen from flow modeling of the blade cooling problem. The two ends of the flat channel are open and five evenly spaced air jets of equal strength at the upper wall configure a symmetrical flow around the mid-slot symmetry axis. The parameters that govern the flow characteristics of such a system are; the channel height, the jet spacing, and the jet velocity. In the analysis, the slot width is kept constant, but the channel height to slot width ratio (), and the slot spacing ratio () vary in the range of 1-3 and 2-4 respectively. In addition, the flow Reynolds number (Re) is altered in a range between 1500 and 10500 for each channel geometry of nine combinations. In experiments, the pressure distributions by an electronic micro-manometer, and the velocity profiles by a hot-wire anemometry system are measured. In numerical approach, the realizable turbulence model with enhanced wall treatment is used for the turbulence computations. Comparisons with the experimental data obtained under isothermal conditions allow evaluation of the performance of the numerical model. The results show that the channel height is the dominant parameter that affects the flow characteristics and a correlation is proposed for determining the pressure drop coefficient of the injection section.

]]>Salah Uddin Mahathir Mohamad Mahmod Abd Hakim Mohmad Obaid Ullah Mehmood MGhazali Kamardan and Rozaini Roslan

This paper aims at the heat transfer phenomenon and the effect of magnetic field on the second-grade fluid in a vertical oscillating cylinder. By applying a perpendicular magnetic field, the fluid gets magnetized. Fractional MHD flow was modeled with Caputo-Fabrizio non-integer derivative approach. Exact solution of the governing equations was obtained by Laplace and finite Hankel transforms. Mathematical computations and graphical plots were used to investigate the quantitative effects of emerging dimensionless physical parameters on the second-grade fluid flow, such as magnetic field and Prandtl number.

]]>A Tuama Alomai M Muhamad Mohammed M Fayyadh Hayder R. Jasim Hasan Shaheed Mohammed Hakim and Ali A Abdulridha

This paper studied the effects of suction/blowing parameters of magnetohydrodynamic (MHD) nanofluid’s viscous flow over an exponentially stretching sheet. In this work, nanofluid flow of water-based copper was considered as a nanoparticle. The radiation parameters, velocity and thermal slip constraint, and magnetic field were applied in similarity transformations to solve the nonlinear ordinary differential equations (ODEs) approximately by reducing the nonlinear partial differential equations (PDEs). The obtained numerical results of velocity and temperature against different values of suction/blowing parameters with varying profiles were displayed and analyzed by using Maple 18 software based on the fourth-fifth order Runge-Kutta Fehlberg technique with shooting method. The dimensionless Velocity decreased with the increasing magnetic field, suction/blowing, and thermal slip condition parameters. Whereas, the profiles of temperature intensified with the growing magnetic field, velocity slip and thermal radiation parameters. Finally, in the experiment, the effect of increased velocity and thermal slip parameters in general caused decrease in the heat transfer with base fluid, but in case of nanofluid this impact was lesser. Alternatively, it can be stated that the effect of suction/blowing parameter caused a decrease and then an increase in the heat transfer.

]]>Abubakar Kazeem Amkpa Job Ajala Mohammed H. Rady Nur Azam Badarulzaman and Wan Fahmin Faiz Wan Ali

Hardness (H) may not be sufficed as a property the same way density (ρ) felt short as a measure of physical property, hence there is the need to correlate H with other property (ies). The porous nature of the material, dislocations and addition of constituents to the aluminium matrix affect the conductivity (Ծ) of alloys among other defects. In this article, attempt to fill the gap in recycling beverage can (RBC) for bumper beam applications was made by producing a 7xxx alloy from 3xxx alloy. About 80 % of the raw materials used in this alloy were sourced from secondary means. Stir casting route was adapted. Aluminium (Al) chips, 70 % Cu- 30 % Al, Manganese (Mn) and Magnesium (Mg) were charged in that order. The relationship between Ծ, H and ρ of the new alloy was established in the As-Cast (AC), annealed (O), natural aged (T4) and artificial aged (T6) conditions. In AC, an alloy of Al- 4.0 Zn-1.5Mg-0.35Cu-Mn recorded the peak obtainable Ծ and H of 3.7x10^{7} m/S and 113.06 Hv with a ρ of 2.7464 g/ cm^{-3}. The same alloy recorded peak Ծ and H in the O condition of 3.7x10^{7} m/S and 102.6 Hv, whereas the ρ was 2.752 g/ cm^{-3}. The T4 heat treatment (HT) deviated when the peak Ծ was 3.7x10^{7} m/S, H and ρ were 58.94 Hv and 2.7551 g/ cm^{-3} respectively. T6 conditioned alloys delivered peak Ծ of 3.7x10^{7} m/S in an alloy of Al- 4.0 Zn-1.5Mg-0.35Cu-Mn with a ρ of 2.7853 g/cm^{-3} and 60.26 Hv. HT and formation of precipitates were detrimental to Ծ and beneficial to H. Curve fittings were obtained and used in developing linear models for the relationship between H and Ծ within respective conditions unique to the experimental alloys.

Abubakar Kazeem Mohammed H. Rady Amkpa Job Ajala Nur Azam Badarulzaman and Wan Fahmin Faiz Wan Ali

The need to turn around the beverage can recycle table from conventional can-can to can-automobile (bumper applications) that was seen as a gap to be filled through a novel Experimental 7475 Aluminium Alloy (X7475). In this study, Aluminium, Zinc, Manganese and Copper were sourced from Recycled Beverage Can (RBC), spent DR 20-BG/T 8897.2 - 2008 Hawk battery and coils of used standing fans respectively. Experimental samples were stir cast. Morphological investigations on over 35 sites revealed elemental composition, nature of defects and possible phases. Annealed (O), naturally aged (T4) and artificial aged (T6) samples were indented for hardness (H). Imperfections and inclusions such as C, O (pores), Na and Fe were observed in the α-Al phase. Hardening precipitates like MgZn_{2}, Mg_{3}Zn_{3}Al_{2}, Mg_{32} (Zn, Al)_{49} and Al_{0.5}Fe_{3}Si_{0.5} were identified. Peak obtainable H of 140.45 Hv (T6), 134.32 Hv (T4) and 89.11 Hv (O) with the least H of 52.18 Hv. Pores and casting defects were observed due to the production route and constituents from secondary sources which affected the mechanical properties. Future research should focus on Optimization of Mechanical Properties. H should be correlated with tensile strength. The use of alumina crucibles may be options.

Khairani Nasir Azrin Hani Abdul Rashid Nurul Atikah Abd. Razak Muhammad Farid Shaari Mohd Nazrul Roslan Shazarel Shamsudin Mohd Shukri Ansar Siti Nor Hawanis Husain Syafiqah Dzulkefli and Noraini Marsi

Recently, plastic waste has become one of the global issues which contributes to severe environmental pollution and threatens marine life as it takes a longer time to decompose. This study was aimed to protect the environment by recycling waste materials to reduce solid wastes. Recycled polyethylene terephthalate string was used in the study to identify tensile properties. The main aim of this research was to identify the tensile strength properties by investigating different string sizes for the r-PET bottle (4 mm, 5 mm, and 6 mm) at different cutting axes (horizontal and vertical). According to ASTM D882-02, the tensile strength test was conducted with a load cell of 50 N and crosshead speed of 50 mm/min at room temperature. To reduce the possibility of nuisance factors that will affect the result, five repetitive tests were carried out and Minitab R.18 software was used to analyse the obtained data. Results revealed that the 4 mm string in both cutting axes demonstrated the highest strength of tensile performance and modulus elasticity.

]]>Sugiono Sugiono Agung Sedaju Oyong Novareza and Dwi H. Sulistyorini

Train aerodynamic performance greatly affects the efficiency of driving energy and passengers’ comfort. This paper aimed to simulate several forms of train models that produce low and stable aerodynamic obstacles as well as low noise at medium speeds of 120 – 1 50 km/hr. The first step to do was the study of literature on train design models, aeroacoustics, aerodynamics, and human ergonomics. Existing 3D CAD and S-R train models with slender ratios = 4, 6, and 8 were tested using Computational Fluid Dynamics (CFD) and Computational Aerospace (CAA) to determine the impact of airflow. The models that have been built were tested at medium speeds of 120 to 150 km/hr. The final simulation results showed that the existing train produced a drag coefficient (Cd) of around 1.27, average noise of 35.9dB, and fuel requirements by 1.7 liters/km. It is different from trains with a slenderness ratio = 6 that produces the best aerodynamic performance with a drag coefficient (Cd) around 0.436, average noise of 9.4 dB, and fuel consumption of 0.73 liters/km. The results concluded that the medium speed needs to adjust the S-R train model with a slenderness ratio = 6 that can produce an aerodynamic performance to improve train user comfort and save fuel.

]]>Erry Rimawan Muhammad Kholil and Sarah Fachira

PT. Suzuki Indomobil Motor is a leading automotive company in Indonesia that produces products in the form of cars and motorcycles, a quality phenomenon that occurred during January 2019 at PT. Suzuki Indomobil Motor there is a high silver streak defect in the injection molding section with 169 back door license garnish that are attached to the machine A02. With this phenomenon, this study aims to determine the injection molding process using value stream mapping and improve the quality of the garnish back door license products using the DMAIC. The results obtained showed that there was a changeover time dies on the Machine A02 that was as high as 57.15 minutes with uptime values and the highest type of defect was obtained using the pareto diagram namely silver streak defect with a percentage of 43%. So from the recommendations obtained by using the value stream mapping to minimize the changeover time dies of the Machine A02, namely by heating the dies first before dies go up to the injection machine, and recommendations obtained from the DMAIC method that is by controlling the stock of material and temperature in the hopper dryer.

]]>Oke Oktavianty Shigeyuki Haruyama Yoshie Ishii and Zefry Darmawan

One of the operational issues that are generally encountered on the print-head performance is residual vibration. For good performance of droplet, the satellite and ligament of an ink droplet must be suppressed during the jetting process. It was proved that the suppressing vibration is viable to control the droplet’s speed and volume. Two kinds of suppressing vibration with front and back position of suppressing pulse from the main pulse were investigated. The suppressing vibration was proved to be an effective way of damping the residual vibration and reducing the droplet volume and speed. By analyzing two types of actuation waveform effect on droplet quality, this paper analyzes the distinctive effect of front and back suppressing vibration on droplet quality.

]]>Debrina Puspita Andriani Azizah Putri Nur Aini Intan Mardiono and Adam Khano

Pull type is production that is based on actual demand and requires a fast and precise manufacturing process in the system. The conventional method caused consumers‘ frequent dissatisfaction with the results and took long production times and high cost. The purpose of this study was to compare between the application for conventional methods and Computer Aided Process Planning (CAPP) method in pull-type production system. Starting with identifying the problems that exist in the results of observations in the field study, then setting the goal of improving the initial production method. Furthermore, the process was conducted by comparing production time using time study method and breaking even calculation. The results show that CAPP method obtained the reduction in the cost and time production than conventional methods.

]]>Muhamad Arfauz A Rahman Muhamad Hakim Rahman Effendi Mohamad Azrul Azwan Abdul Rahman Mohd Rizal Salleh and John P. T. Mo

This manuscript presents the optimization work of vision inspection at the semiconductor industry, focusing on the top view vision inspection. The top view vision inspection includes checking the tip to tip, lead to lead and laser marking of the product. In this work, the focus was on enhancing the potential vision parameter that causes over-rejection. The work started with the identification of the vision parameter that contributes to the over-rejection by the vision system. Three factors have been identified, which are the lead shutter time, laser shutter time and brightness value. All factors were tested using the design expert software. A comprehensive data collection was conducted to gather essential measurements by the vision system. Upon completion of the data collection, the optimization of the parameters was done using the full factorial method. At the end of this work, the optimized parameter setting has been validated using the dedicated machine, and monitoring of the result has been conducted based on the defined timeline. Post the optimized parameter setting, the vision was able to capture measurement value similar to the drawing value within the acceptable tolerance. This work has significantly reduced over-rejection and has indirectly improved the production rate.

]]>Varun Potty Sohan Angelo P. Srinivasa Rao and Srinivas G

Expressed in nature’s infinite subtleties, the Fuselage draws its inspiration from the streamlined body of a bird or a fish, channelizing the flow of air around, enabling its ease in flight. Spanning most of the aircrafts structure, it plays a crucial role in the ferrying of people and cargo, simultaneously balancing the shears due to the empennage and wing structures all in mid-air. Its structural integrity is often questioned by failures due to load or bad air during maneuvers, causing instability which has led many to intensively explore and develop an ideal fuselage. The behaviour of the fuselage is crucially determined by the structural integrity and aerodynamic performance. This paper is an attempt at collating the recent technological advances pertaining to the fuselage. We’ve streamlined and categorised the wide-ranging scholarly articles by three fundamentally varying approaches - Theoretical, Experimental and Numerical. The theoretical approach saw the authors test out their hypothesis by utilizing and constructing various mathematical models using scientific principles with no verification by actual experimentation or simulation work. The experimental approach pertains to those papers whose authors devised experiments, whose data was used to draw distinct conclusions. The numerical approach mainly dealt with heavy computational analysis using FEM and CFD analysis. Therefore, this paper serves as a compendium for researchers and developers attempting to familiarise themselves with the current advancements and developments in domain of fuselage technology.

]]>Sohan Angelo Varun Potty P. Srinivasa Rao and Srinivas G

Over multiple iterations spanning many years of research a stable and aerodynamically workable fuselage structure has been zeroed down on. The fuselage being the segment holding the passengers and crew requires an immaculate degree of stability during takeoff, landing and flight. Aerodynamic optimisation presupposes every notion of this ‘in flight stability’. The recent interest taken in the field of stability under unforeseen air conditions has led to remarkable developments in the field of aerodynamics. This paper attempts to categorically classify these interests into 3 sections- Theoretical, Experimental and Numerical. Various mathematical models and algorithms have been created to study and test the stability of the fuselage under turbulent conditions caused by weather. Turbulence caused by on flight equipment (propellers etc) and methods for its mitigation have also been mentioned. The chine angle analysis of the fuselage reveals that a sharper angle is more favorable in increasing the lift. The study of asymmetrical vortices and its evolution has enhanced the field of aerodynamic optimization. Unconventional aircraft designs like the BWB are studied and compared against the incumbent structures. Various modeling softwares like CATIA have extensively been used to design these structures. A compilation of these recent developments has been presented to those attempting to intensively analyse and study the field of aerodynamic stability.

]]>Ashwini Anand Gaonkar Poornima Menon and Srinivas G.

Missile is a self-propelled vehicle flying at supersonic speeds. Their payloads are usually explosive and are also known as warheads. These warheads are used to destroy a pre-set target. The aim of this paper is to optimize the values of the lift and drag forces on the given missile for better aerodynamic performance, by carrying out numerical simulations over the supersonic missile by varying the angle of attack through a set of suitable boundary conditions, while keeping the Mach number of the missile as a fixed parameter. Aerodynamic performance of the missile is studied by varying the angle of attack from 0 to 12 degrees. For every angle of attack, the coefficient of lift and coefficient of drag variations were studied in detail and were compared with the existing literature survey so as to obtain the maximum value of C_{L}/C_{D} ratio in order to improve the efficiency. A model of the missile was designed to-scale on Space Claim and the flow analysis was done on FLUENT standalone system using ANSYS 16 workbench. The results obtained, were in the form of flow contours of parameters such as velocity, temperature, density, pressure and turbulence. Through these flow contours the maximum and minimum values of all parameters, as well as the variation in these parameters were estimated. From the numerical analysis it was found that maximum value of C_{L}/C_{D} ratio was 2.5 at 12^{o} angle of attack. It was also found that the velocity increased with increase in angle of attack and increased the efficiency. These results are advantageous upcoming to designers who aim to build aerodynamically efficient missiles.

Man Djun Lee Jia Yong Chan Jasper Ling and Pui San Lee

This study aims to develop a water pump that utilizes natural hydro energy as driving force to deliver water to a higher ground. The conceptual design of using water wheel to extract kinetic energy from water flow and transfer the energy to power multiple piston pump was created based on the extensive literature review findings. The actual prototype is then built and modified to suit the actual environment considerations. Findings show that single pump is able to produce maximum pressure head of 7.14 meters and the maximum volume flowrate achieved is 19.2 l/hr (320ml/min). However, when multiple piston is connected in series (in this research three pistons is used), the maximum water head increased to 13.77 meters and the maximum volume flowrate about 19.2 l/hr. This result shows that the water pump can be used in remote area or places at higher ground that does not have constant water access. Performance of the whole system can be improved by several factors such as adding more blades to the water wheel, steeper angle and better piston shaft design for water pump, and also proper water sealing of the whole system to prevent head loss and increase the overall performance.

]]>Louiz Akram

In many industrial fields, there is an ever growing market demand for highly profitable engines. This fact encouraged to produce very developed engine parts, namely sophisticated injection systems. Consequently, the electronically enhanced injection systems are becoming very widespread for their high efficiency and cause the mechanical automatic systems to be neglected without enough studies. However, the electronically commanded injection is difficult to maintain because of the risks of short-circuits, and it is also difficult and expensive to repair since its captors are in high pressure and temperature areas. This paper aims to introduce a mathematical study of the basic direct injection operation by proving formulas representing forces, velocities and the energy involved in the injection mechanical mechanism without any electronic or computational complications. This theoretical mathematical modeling is useful for the efficiency experimental studies in order to improve the manufacturing and maintenance of all direct injection systems.

]]>Emetere Moses E. and Adeyemo Nehemiah

Photovoltaic (PV) solar panel imported into Africa was observed to have low lifespan due to the spectrum of harmful solar radiation hitting the surface of the PV panel. In this research, the bio-filter was synthesized using plant extract and silver. The dark room experiment was carried out to examine capacity of the PV panel accept specific radiations. The bio-filter was sprayed on the PV panel and the measurement for a sprayed and unsprayed PV panel were obtained. It was discovered that the bi-filter was effective to stabilize the measured parameters such as current, voltage and power.

]]>Quang-Cherng Hsu The-Vinh Do and Thi-Nguyen Nguyen

In this study, the efficiency of minimum quantity lubricant (MQL) was demonstrated during hard-milling of AISI H13 steel with a carbide-coated (TiAlN) cutting tool. A comparative analysis was done to prove the effectiveness of MQL versus the dry cutting method based on certain process parameters such as surface roughness and cutting force. The L27 orthogonal array of the Taguchi method was used for designing the experiment. An analysis of the influence of cutting parameters including cutting-speed, feed-rate, depth-of-cut and hardness-of-workpiece on the cutting force and the surface roughness was carried out by using the response surface methodology (RSM) and analysis of variance (ANOVA). The result shows that under both of the cutting conditions (MQL and dry), feed rate and depth-of-cut are main factors affecting surface roughness and cutting force. Further, quadratic mathematical models for predicting cutting force and surface roughness under dry cutting and MQL conditions were established. The analysis of the roughness and the cutting force showed the outstanding effectiveness of MQL when compared with dry cutting.

]]>Manjunatha N and Sumithra R

The problem of triple diffusive surface tension driven magneto convection in a composite layer is investigated for linear, parabolic and inverted parabolic temperature profiles. The corresponding thermal Marangoni numbers are obtained analytically depending on various physical parameters of interest. The parameters which are effective to enhance convection and to control convection are determined. From the investigation it is found that the linear profile is suitable for fluid layer dominant composite layer whereas parabolic and inverted parabolic profiles are conducive for the porous layer dominant composite layer.

]]>Khemisara Kulmart and Nopparat Pochai

The purpose of this research was to develop a mathematical model for controlling salinity intrusion in Chao Phraya River, Thailand, using one-dimensional advection-diffusion equation. There have been many research studies that applied a mathematical model called dispersion model to estimating salinity concentration. Our proposed dispersion model is simple, using very few parameters, but can simulate salinity intrusion adequately. We used MacCormack scheme to approximate salinity intrusion and cubic spline interpolation technique to approximate field data including initial salinity concentrations and the concentrations at the left boundary. The MacCormack scheme and Cubic Spline interpolation technique were quite suitable for approximating real data, and the proposed mathematical model was able to predict salinity intrusion adequately.

]]>Moch Iqbal Rokhim Mohd Shukri Yob Mohd Juzaila Bin Abd Latif and Fudhail Bin Abdul Munir

I-beam is widely used as main structures in the automotive and oil and gas industries due to their ability to sustain axial load at very minimum weight. For any structure, the important parameter should put into considerations are strength and stiffness. A Three-point bending test is a well-known method to evaluate the strength and stiffness of a beam. The existing machine to perform a three-point bending test is the Instron® 5585 Universal Testing Machines (UTM). However, these machines can only measure specimen within 500 mm which is insufficient for a longer specimen. In this study, a new design testing rig was proposed to evaluate the strength and stiffness of the longer specimen of I-beam. For this study, the design of the testing rig was evaluated using finite element analysis for 3 different lengths to determine its strength and rigidity. From this analysis, it is found that the proposed design of a testing rig shows satisfactory strength and rigidity for the length of 500 mm to 1000 mm when loaded with 10 kN force.

]]>A. A Fondjo and T. C Dzogbewu

The stress raisers factor around circular holes in a plate exposed to uniform tensile load at the edges has been studied using Finite Element Analysis solvers. The effect of mesh quality on stress raisers factor, the maximum Von Mises stresses, the computing time, and the percentage error has been examined. 4 Node Quadrilateral Element and 8 Node Quadrilateral Element were utilized respectively as first-order component (4NQE) and higher-order component (8NQE) to assess the maximum Von Mises stress and the numerical stress raiser factor (Kn) at various mesh sizes. The maximum Von Mises stress and the stress raiser factor were determined using the following finite element solvers: ABAQUS, ANSYS, CATIA, STRAND 7, ALGOR, COSMOS/M, and FEMAP. The estimations of the numerical stress raiser factor (Kn) were compared with the theoretical stress raiser factor (Kt). There were discrepancies observed between the maximum Von Mises stresses of the FEA solvers.

]]>Taoufik Kriflou Mohamed Rachik Lahcen Azrar and Khalid EL Bikri

The transverse spherical impact on an elastic-plastic beam is formulated and investigated herein. Both semi-analytical procedure and finite element (FEM) solution are elaborated. The semi analytical solution combines a finite difference method with the Hertz contact theory. The transient response of impact beams is computed by considering the loaded and unloaded phases. The contact force calculation is based on the model proposed by Stronge. To validate our semi-analytical model, a 3D finite element model has been developed. The comparison between the predictions from the presented semi-analytical and those from the 3D finite element models shows that the semi analytical model achieves very accurate predictions at a marginal computational time.

]]>Ahmet Atak

The strength, failure location and modes of AZ31B Magnesium sheets with 1.5 mm thickness, joined using friction stir spot welding (FSSW), can be determined using tension-shear tests. However, the joined materials have different tension test and elastic-plastic characteristics. Elastic analysis methods for spot welding have been examined in detail in literature. However, if the material has narrow elastic and large plastic area characteristics, such as AZ31B, elastic-elastic analysis methods are deficient. The development and application of elastic-plastic analysis methods are required for such soft metal materials. In this study, the elastic-elastic and elastic-plastic analytical stress mechanisms were investigated. Strain and force equations were then derived using an analytical approach. These developed equations were based on the FSSW-Tension-Shear-Test and verified using Finite Element Method (FEM)-Analysis and tension-shear tests. In addition, the location of failure was also determined. It is possible to predict failures without performing tension-shear tests using the proposed analytical equations.

]]>J. Jagadesh Kumar G. Diwakar and V. V. Satyanarayana

In the current research, pressure bearing capacity of AISI 316L austenitic stainless steel is evaluated under fatigue loading through finite element method (ANSYS 18.1) for a specimen with no notch on its surface. Thereafter, the pressure bearing capacity of the same specimen is evaluated with rectangular and V-notches at the center. The notch geometry is changed in terms of its width, depth and the notch central angle (perimeter length) for each of the rectangular and V-notched cases. Fifteen types of rectangular notch and V-notch geometries are undertaken for the research as required by Box-Behnken model of Response Surface Methodology (RSM) analysis. The primary objective of the research is to evaluate the impact of notch geometry on the pressure bearing capacity under fatigue loading conditions. It is observed that fatigue life degraded more with V-notched specimens when compared to rectangular notched ones. Regression equations are developed and surface plots are generated for both rectangular and V-notch cases for the pressure bearing capacity which is dependent on width, depth and notch central angle.

]]>Huu - Phan Nguyen and Ngoc - Vu Ngo

The vibration integrated into die-sinking electrical discharge machining is a relatively new solution, so it has been creating the interest of researchers. In this paper, the authors studied the effect of low frequency vibration attached onto workpiece to efficiency of die- sinking electrical discharge machining. Copper electrode and SKD61 die steel were selected to investigate. Material removal rate, tool wear rate and surface roughness were quality indicators investigated in this study. Experimental results showed that the low frequency vibration has a positive effect on the efficiency of die-sinking electrical discharge machining. Comparing to die- sinking electrical discharge machining traditional, when the vibration unit is integrated onto work-piece in die-sinking electrical discharge machining, the largest increase of material removal rate was 34.94 %, the greatest reduction of tool wear rate was 16.0 % and the largest reduction of surface roughness was 26.36 % and profile of machined surface was better.

]]>Shivesh Kumar and Sunil Kumar

Arduino based design of economic and real-time fuel consumption rate computing by digital mileage meter is intended to develop effective and economic mileage meter that can promptly exhibit fuel mileage of a vehicle and show it. This device can be added to augment the existing running automotive system also, which works on carburetor or for that matter fuel injection technology. The cumbersome task of computing and manually checking the mileage can be automated using this device. Infra-red and position sensors have been assembled with Atmega328P microcontroller and installed on the motorbike. The efficacy of the designed mileage meter is revealed by comparing results with literature and real condition.

]]>A. Redjechta F. Djeddou and H. Ferhat

The objective of this work is to perform a synthesis of a cam mechanism of the first species, with translating flat-face follower, based on deterministic and probabilistic approaches. The study consists of two parts: the first consists of optimization of the mechanism to obtain an optimal size and ensure a more efficient operation, taking into account the three major parameters that generally influence the design of this type mechanism, namely the base radius of the cam, the length of the plate and the eccentricity of the rod. In addition, the constraints related to the performance and resistance indicators as well as the geometric conditions are taken into account. The second part of this work is devoted to the reliability analysis whose probability of system failure is estimated by the approximate methods: FORM / SORM and Monte Carlo simulation, using the software Phimeca Software. Sensitivity measurements have demonstrated their effectiveness on system reliability by making it more robust.

]]>Waluyo Adi Siswanto and Bayu Putra Martama

This study aims to identify the stress concentration and distribution pattern in the mid-cross-section of a concrete block in a four-point bending (FPB) test with notch and without notch using a finite element method (FEM). The research was preceded by a meshing sensitivity analysis (MSA) with verification of reference from FPB test deflection theories. The selected finite element model was then used for numerical FPB testing with load variants of 100 kN, 200 kN and 300 kN. Simulation test results show that the greatest stress and deflection of the model from the FPB simulation with notch occur in the mid-bottom area, while in the model without notch the strongest stress takes place in the mid-bottom area and the largest deflection in the mid-center area. The influence of load variation indicates that the greater the load, the greater the stress concentration and deflection around the notch. Simulation by FEM can replace real material tests by means of the finite element model applied in this study.

]]>Mohamad Mustaqim Junoh Fadzilah Md Ali Norihan Md Arifin and Norfifah Bachok

The steady stagnation-point flow of nanofluid over a stretching or shrinking sheet in its own plane is investigated. The governing nonlinear partial differential equations are transformed into a nonlinear ordinary differential equations via the similarity transformation before they are solved numerically using the bvp4c solver in the MATLAB. Three different types of nanoparticles (Cu; Al_{2}O_{3}; TiO_{2}) in the water-based fluid are analyzed in this paper. Effects of the solid volume fraction ϕ on the fluid flow and heat transfer are evaluated. Numerical results are obtained for velocity and temperature distribution, as well as the skin friction coefficient and local Nusselt number are presented graphically. There exist dual solutions for a certain range of stretching/shrinking parameter ϵ. Therefore, a stability analysis is performed to determine which solution is linearly stable and physically realizable. From the stability analysis it is found that the first solution is stable whilst the second solution is not.

Fahad AlHarbi Abdullah AlRomaih Sulaiman AlHudaithi Abdullah AlHusayyani Talal AlQadhi Ali Sulaiman Alsagri Abdul Rahman Alateyah and M. Shameer Basha

A complete air conditioning system has been developed to control ambient conditions such as temperature, relative humidity, air movement, etc. in an economical manner for AlFahad Mosque located Unaizah in qassim region K.S.A. In this paper, the calculations were carried out taking into account the ASHRAE standards. For space references and calculations, the plan is developed by AUTO CAD. After taking the plan investigated the location and materials used for construction, based on the study theoretical thermal load calculations were performed by the E20 Method for number of rooms as per the plan and summarizing. The present plan has one huge room of each floor. Based on the heat load calculations, cfm values were found for number rooms and summarized for entire building. Obtained the cfm for first floor as one room and ground floor as one room and add for total cfm for the AlFahad mosque. The object of the paper is about the cooling load calculation for the AlFahad Mosque at Unaizah Qassim Region Saudi Arabi (K.S.A.). The load calculation is carried out by using E20 Manually and HAP software. Nowadays, people are estimating the load calculation by approximation method i.e. by giving dimensions of building which the sellers are estimating roughly tonnage of refrigeration (market method or ALGhaith company method). These cooling load calculations obtained, which is under or over the comfort condition. To overcome this problem, the cooling load calculated by E20 manual method, HAP software and compared.

]]>Mohamad Hidayad Ahmad Kamal Noraihan Afiqah Rawi Mohd Rijal Ilias Anati Ali and Sharidan Shafie

The unsteady three dimensional boundary layer flow near a stagnation point region is studied numerically under the influence of microgravity environment. The boundary layer plate was embedded by the nanofluid with nanosized copper particles and water as a based fluid together with thermal radiation effect. The problem was mathematically formulated in term of coupled governing equations consisting of continuity, momentum and energy equations derived from the fundamental physical principles with Tiwari and Das nanofluid model. Boundary layer and Boussinesq approximation were then applied to the coupled equations and then reduced into non-dimensional equations to lessen the complexity of the problem using semi-similar transformation technique. Implicit finite different method known as Keller box method was used in this problem. The problem was then analyzed in terms of physical quantities of principal interest known as skin frictions and Nusselt number which explained the flow behavior and heat transfer analysis. From the outcome of the analysis, it was found that the parameter values for curvature ratio lead to the different cases of the stagnation point flow which is either plane stagnation flow or asymmetry stagnation flow. On the other hand, by increasing the nanoparticles volume fraction which is one of the nanofluid parameter may increase the skin frictions on both x- and y- directions. The presence of thermal radiation parameter was found to have increased the rate of change of heat transfer at the boundary layer flow.

]]>Fasihah Zulkiflee Ahmad Qushairi Mohamad Mohd Rijal Ilias and Sharidan Shafie

This paper studied unsteady free convection flow between two parallel plates with mass diffusion. One of the plates is considered oscillating. Appropriate non-dimensional variables are used to reduce the dimensional governing equations along with imposed initial and boundary conditions. The exact solution to velocity, temperature and concentration profiles are obtained using the Laplace Transform technique. The graphical results of the solutions are presented to illustrate the behavior of the fluid flow with the influence of Schmidt number, Prandtl number, oscillating parameter, Grashof and mass Grashof number. The corresponding expressions for skin friction, Nusselt number and Sherwood number are also calculated. It is observed that increasing Prandtl and Schmidt numbers will increased the Nusselt number but decreased the skin friction.

]]>Ahmet Atak and Aydın Şık

Design affects the entire lifespan of a product. Humans design ideas in their environments, especially to meet their own needs. People come to design ideas and abilities from various objects and events in nature, and use these to increase their design capabilities. With the increase in human population, proliferation of product needs, and the dangerous use of products, the ethical risks have increased. The risks within unethical designs have now reached all levels of human life. Products have been introduced to the market without considering their ethics, and in many of them, only the material purpose has been pursued, instead of the benefit to humanity. This research focused on the goal of the product designers, which is to design and develop a product, while contributing to the awareness that the product needs to be subjected to both risk and ethical analyses as with all other requirements. The dominant task of this study is to enable designers and their designs to develop their own ethical discourse and concepts. In doing so, the most forward aim is to not damage humans, but to design what is useful. The impact on the designer is to have ethical responsibility for their designs.

]]>Gurdeep Singh Khushdeep Goyal and Rakesh Goyal

The present work investigates the effect of hot corrosion on ASTM-SA213-T-22 Steel with different coatings of Al_{2}O_{3-}TiO_{2} at 900℃ in molten salt environment (40wt %Na_{2}SO_{4}+60wt%V_{2}O_{5}). The experimentation consisted of 50 cycles of heating coated and uncoated specimens for 1 hour at 900℃ in muffle furnace and cooling for 20 minutes at ambient temperature. The corroded specimens were analyzed using visual examination, weight change measurement, X-ray diffraction technique and Scanning electron microscopy/Energy-disperse X-ray analysis. The results showed that the uncoated substrate had been more affected with corrosion and gained more mass due to formation of iron oxide (Fe_{2}O_{3}) as compared to coated substrate because of better adhesion of Al_{2}O_{3} coating with base metal SA213-T22 due to presence of TiO_{2}. The presence of TiO_{2} increased the strength and durability of Al_{2}O_{3} coating to withstand with high temperatures.

Cebrail Ciflikli and Bilgin Yazlik

In a wireless communication system, cooperative diversity can be used to combat fading effects. In cooperative diversity, the system uses idle antennas, which are located at different locations, as relays. Cooperative communication with OFDM is widely used in communication systems and it enhances communication performance of the system. There are different methods to enhance the performance of OFDM systems, carrier interferometry code is one of them. While, carrier interferometry code increase the performance of the system and also reduces PAPR level. Carrier interferometry codes can be implemented on an OFDM system by using FFT and wavelet. In this paper we investigate the effect of the relay position on the carrier interferometry cooperative OFDM system which uses wavelet transform. The effect of the relay position is investigated over different combiners and relaying strategies. The results show that, relay position effects the performance of the system and optimal location for the relay is right between source and destination.

]]>Nina Penkova Petar Chervenliev Boian Mladenov and Kalin Krumov

An algorithm for numerical simulation of transient moisture content fields and mechanical processes in ceramic ware at drying in industrial aggregates is developed. It is based on mathematical models of the mass transfer and mechanical behavior in the ceramic bodies, data for the drying regime and physical properties of the material as function of water content. The models allow variations of the drying conditions in order to choice the most efficient regime at existing or design dryers. The algorithm is applied for a direct coupled finite element analysis of wet bricks behavior in continuous working drying installation. The shrinkage mode, modulus of elasticity, Poisson ratio, modulus of rupture, effective mass transfer coefficient and critical moisture content are determined by experimental tests of the material. They are used to simulate numerically three-dimensional moisture, stress and strain fields in ceramic bodies at the existing drying regime. Ways for improvement of the models and their application for estimation of the potential for energy savings in industrial dryers are discussed.

]]>Indermeet Singh Khushdeep Goyal and Rakesh Goyal

Different coating with varying quantities of Al_{2}O_{3} and ZrO_{2} were fabricated on the SA213 T-91 steel using plasma spray method to study hot corrosion resistance behavior. Experiment was conducted under the molten salt environment of 60% Na_{2}SO_{4}-40%V_{2}O_{5} at a temperature of 900℃ inside a furnace for 50 cycles. Each cycle consisted of 1hr heating and 20 min cooling at room temperature. Results were examined using the visual inspection, weight change measurement, X-ray diffraction technique and Scanning Electron Microscopy/ Energy Dispersive X-Ray Spectroscopy (SEM/ EDS) analysis. Results showed that uncoated T-91 steel was more prone to hot corrosion as compared to coated steel specimens. It was noticed that ZrO_{2} reinforcements in Al_{2}O_{3} coating matrix helped to enhance corrosion resistance of these coatings. The corrosion resistance increased with increase in ZrO_{2} content in coating matrix.

Nam Woong Kim and Haeng Muk Cho

This study examines the characteristics of the steering stability performance of a vehicle with varying tire cornering stiffness. The vehicle and its front and rear tire models, which are the basis of simulation, were fabricated using SPMM and Flat Trac, respectively. Tire cornering stiffness of the front and rear wheels was modulated by changing the LKY, one of the scaling coefficients in the tire model. Steering stability performance evaluation is based on frequency response (ISO7401)[1] which can analyze the dynamic characteristics of the vehicle with varying steering input cycle and Steady State Speed (ISO4138)[2] which enables dynamic analysis of the vehicle with varying transient inputs. The results were analyzed by using measurement assessment factors with high correlation with actual stiffness evaluation. As a result of the evaluation, it was confirmed that the steering and stability performance of the vehicle increase when the cornering stiffness of the front wheel is increased and the cornering stiffness of the rear wheel is decreased, which has enabled us to identify the direction of development of real tires. It is expected that this study will be a starting point to improve the efficiency of the research and development to identify the cause of the decline of the running performance of the tires and the way to enhance it.

]]>Najiyah Safwa Khashi'ie Norihan Md Arifin Ezad Hafidz Hafidzuddin Nadihah Wahi and Mohd Rijal Ilias

The present study utilized Cattaneo-Christov heat flux model for solving nanofluid flow and heat transfer towards a vertical stretching sheet with the presence of magnetic field and double stratification. Thermal and solutal buoyancy forces are also examined to deal with the double stratification effects. Buongiorno's model of nanofluid is used to incorporate the effects of Brownian motion and thermophoresis. The boundary layer with non-Fourier energy equations are reduced into a system of nonlinear ordinary (similarity) differential equations using suitable transformations and then numerically solved using bvp4c solver in MATLAB software. The local Nusselt and Sherwood numbers of few limited cases are tabulated and compared with the earlier published works. It showed that a positive agreement was found with the previous study and thus, validated the present method. Numerical solutions are graphically demonstrated for several parameters namely magnetic, thermal relaxation, stratifications (thermal and solutal), thermophoresis and Brownian motion on the velocity, temperature and nanoparticles volume fraction profiles. An upsurge of the heat transfer rate was observed with the imposition of the thermal relaxation parameter (Cattaneo-Christov model) whereas the accretion of thermal and solutal stratification parameters reduced the temperature and nanoparticles concentration profiles, respectively.

]]>Nurazleen Abdul Majid Nurul Farahain Mohammad Abdul Rahman Mohd Kasim Mohd Rijal Ilias and Sharidan Shafie

Due to the many applications of micropolar fluid such as blood, paint, body fluid, polymers, colloidal fluid and suspension fluid, it has become a prominent subject among the researchers. However, the characteristics of micropolar fluid flow over a surface of another quiescent fluid with heavier density of micropolar fluid under the effect of constant heat flux are still unknown. Therefore, the objective of the present work is to investigate numerically the forced convection of micropolar fluid flow over a surface of another quiescent fluid using constant heat flux boundary condition. In this study, the similarity transformation is used to reduce the boundary layer governing equations for mass, momentum, angular momentum and energy from partial differential equations to a system of nonlinear ordinary differential equations. This problem is solved numerically using shooting technique with Runge-Kutta-Gill method and implemented in Jupyter Notebook using Python 3 language. The behaviour of micropolar fluid in terms of velocity, skin friction, microrotation and temperature are analyzed and discussed. It is found that, the temperature is higher in constant wall temperature (CWT) compared to constant heat flux (CHF) at stretching or shrinking parameter and various micropolar parameter K. Furthermore, as Prandtl number increases, the temperature is decreasing in both CHF and CWT.

]]>Mohammed Abobaker

In this paper, we take several different analytical and numerical approaches to studying the equilibrium of a gravitating system of a gas-dust cloud. We consider one-dimensional self-gravitating spherically symmetric fluid flow of a gas-dust cloud. We discuss the equilibrium of the system of gas-dust cloud by using simplified analytic stellar, polytropic models. A condition for the equilibrium of the cloud in the form of a differential equation is used. Using mass density in the cloud as a given function, we obtained the corresponding pressure analytically within the cloud and determined the central pressure. In dealing with a polytropic model, we found the analytical and numerical solution of the Lane-Emden equation for the various values of the polytropic index after that, central density and central pressure were obtained. Finally, the density and pressure of the cloud for the various values of the polytropic index are calculated. The result found by the simplified analytical method and the polytropic method is compared.

]]>Nor Hathirah Abd Rahman Norfifah Bachok and Haliza Rosali

In this study, we investigated the problem of steady two-dimensional magnetohydrodynamic (MHD) stagnation-point flow over a linearly stretching/shrinking sheet in nanofluids. There are three types of metallic nanoparticles considered such as copper (Cu), alumina (Al_{2}O_{3}) and titania (TiO_{2}) in the base fluid of water with the Prandtl number Pr = 6.2 to investigate the effect of the nanoparticles volume fraction parameter φ of the nanofluids. In this problem, the governing nonlinear partial differential equations are transformed into the nonlinear ordinary differential equations by using a similarity transformation and then solved numerically using the boundary value problems solver bvp4c in Matlab software. The influence of magnetic field parameter, M on the skin friction coefficient C_{f}, local Nusselt number Nu and the velocity and temperature profiles are presented graphically and discussed. The results show that the velocity and temperature are influenced by the magnetic field and nanoparticles volume fraction. The dual solutions exist for shrinking sheet case and the solutions are non-unique, different from a stretching sheet. The numerical values of and for M=0 are also computed, which show a favourable agreement with previous work.

KB Hamzah NMA Nik Long N Senu ZK Eshkuvatov and MR Ilias

The modified complex variable function method with the continuity conditions of the resultant force and displacement function are used to formulate the hypersingular integral equations (HSIE) for an inclined crack and a circular arc crack lies in the upper part of bonded dissimilar materials subjected to various remote stresses. The curve length coordinate method and appropriate quadrature formulas are used to solve numerically the unknown crack opening displacement (COD) function and the traction along the crack as the right hand term of HSIE. The obtained COD is then used to compute the stress intensity factors (SIF), which control the stability behavior of bodies or materials containing cracks or flaws. Numerical results showed the behavior of the nondimensional SIF at the crack tips. It is observed that the nondimensional SIF at the crack tips depend on the various remote stresses, the elastic constants ratio, the crack geometries and the distance between the crack and the boundary.

]]>Syafikah Ayob and Nor Alisa Mohd Damanhuri

In this paper, a numerical approximation of the stress equation for the indentation of granular materials by a smooth rigid wedge is presented. Plane strain conditions are assumed, and the materials obey the Mohr-Coulomb yield condition. This method determines the deformation of granular material under a smooth rigid wedge punch and construction of stress field in the deforming region which are presented by using MATLAB programme. The granular material is assumed to be in dense, solid like state. The solution only refers to the initial motion after the punch. This was then applied on one type of boundary value problem. By using MATLAB, the value of each point (x,y) and the stress variables (p,ψ) which construct the deformation field are calculated. This method provides simple and reliable algorithms for the solution of the deformation problems involving the stress variables. The results will consequently help in the improvement of the existing labs and experimental facilities in the industries and will eventually increase its efficiency.

]]>A. S. Mariawati N. Wahyuni M. Fawaid A. Umyati M. W. Riesha H. Iridistadi and Henny

The common problems faced by post-stroke patients are the lack of facility and time for exercise in rehabilitation. This research aims to design upper extremity exercise portable equipment. Basic theory of this product's design is the Active Range of Motion. The design of upper extremity exercise portable equipment (P-RAT) using Nigel Cross's Rational Method. As the result of design, we obtained the best alternative solution for upper extremity exercise portable equipment with 43 cm of length, 11 cm of width and cm of height equipped with rail extensions for 10 cm, 20 cm, and 30 cm extra length, as well as the capability of elevation setting of the rails at 0°, 10°, 20°, and 30°.

]]>F. Farhatnia and M. Sarami

This is the first attempt to utilize the refined zigzag theory (RZT) to study the bending and buckling behavior of a functional graded (metal/ceramic) thick beam. RZT, which has been exploited for the analysis of multilayered composite and sandwich beams does not employ shear correction factor. Furthermore, the number of kinematics variables of the RZT is not dependent to the number of layers in comparison with the layerwise theory. With regarding to the numerical solution, RZT, also requires C0 continuity interpolation, which leads to the development of this theory in finite element method. It is assumed that the mechanical properties of the beam varies through the thickness. According to the volume fraction of metal and ceramic, it is discretized across the thickness; consequently, the functionally graded beam (FGB) is modeled as a multi-layered one. The beam subjected to uniformly transverse and axial loadings. The equilibrium equations are established using the principle of virtual work. Using the shape functions of the first and second order forms, the non-isoparametric finite element consisting of three nodes and nine degrees of freedom are extracted. To confirm the excellent accuracy of the present approach, some numerical examples are provided and compared with those available in the literature that reveals that RZT is a trusty and validated theory to analyze the FG thick beams.

]]>Siddikov Isamiddin Xakimovich and Umurzakova Dilnoza Maxamadjonovna

The methodology of creation of automatic control system (ACS) of water level in the steam generator is developed. The mathematical model of checking its working capacity is developed, which allows establishing the maximum deviations of water level without carrying out full-scale tests, without adjusting the settings of tripping actuation according to the water level in the drum. The foreign methods of PID-regulator adjustment in the cascade system of automatic water level control in the boiler drum are considered, on the basis of which an invariant cascade system of automatic control is proposed. The invariant Cascade-System of Automatic Control (CSAC) of water level in a boiler drum is offered. Simulation results of the invariant cascade-system of automatic control in comparison with CSAC, configured with best foreign method, showed a significant improvement in the quality of regulation in all the major disturbing influences. The results can be used in the development of adaptive control systems and other thermal power devices.

]]>Israa Ali AbdulGhafor Adnan A. Abdulrasool and Qasim S. Mehdi

The present experimental study presents the of performance of the combine cooling system (chilled ceiling and displacement ventilation). The experimental study included the effect of different temperatures of chilled ceiling of (20 and 16)℃ and different supplied air temperatures of (18, 20, 22 and 24)℃ with constant internal load of 1600W and constant supplied air velocity of 0.75m/s. The theoretical study content studying the air flow pattern through occupant zone and temperatures contours in different directions X, Y and Z at supplied air temperature (18)℃ and internal load, mean plate temperature and supplied air velocity of (1600W, 20℃ and 0.75m/s) respectively. The experimental results show that the cooling capacity of air decreases as temperature of supplied air increases. At temperature of supplied air increase by 33.3%, the cooling capacity of air decreases by (22.7 and 22.54)% for chilled ceiling temperature of (20 and 16)℃ respectively. While cooling capacity of chilled ceiling increases as supplied air temperature increases. At supplied air increases by 33.3%, the cooling capacity of chilled ceiling increase by (14 and 15.28)% for chilled ceiling temperatures of (20 and 16)℃ respectively. The theoretical results show that the air velocity and temperatures contours for supplied air temperature in different direction are approximated constant.

]]>M. Abobaker

In this paper, we present a simple model for the dynamics of one dimensional of a self-gravitating spherical symmetrical gas-dust cloud. We take two analytical approaches to study the dynamics of a gravitating system of a gasdust cloud. The first approach solves a set of non-linear equation of dynamics of a gravitating system. The second approach is a Cole-Hopf transformation, which is used to simplify the equations of dynamics and after that, we applied the method of characteristics to reduce partial differential equations to a system of entirely solvable ordinary differential equations. The results found by the analytical method and the Cole-Hopf method are compared with each other, showing that both lead to the same result. The obtained results in this study are presented in plots. We used the Mathematica software package in performing calculation and plotting graphs.

]]>Abdullh Saiwan Majli and Satar Habib Mnaathr

Solar energy is obtainable in the earth as an unlimited source of clean energy. There is an increasing bearing in the carbon release in the world. There are two parameters mainly affect the efficiency of the solar system that are solar radiation and temperature. In this research, the Effect of the Solar Irradiance and Temperature on the Characteristic of Photovoltaic in Al-Nasiriya City is studied. PVsyst simulation facility is to be used for design and optimization. A computation has been conducted to verify the change in i-v and p-v characteristics of the system. The suggest model is based on a behavioral cell model for styling solar radiance to electricity transformation and to confirm the different factors assuming the solar PV system competence. The temperature and radiation data has been possessed from the position of Al-Nasiriya City in Iraq south.

]]>Mohammadmahdi Khamsi

Today Unmanned aerial vehicles (UAV) have found widespread use and may have been using them to capture various events or take photographs of operational areas; but the fact is that UAVs or quadcopters, which are some of these flights, are still at the beginning of their journey and can be future applications will be more widely used. Given the geographical situation and the current situation in the world, the country needs to step up with the world in order to strengthen the defense forces. One of the tools that have been used in recent decades to other tools due to their characteristics and their unique features, including the absence of human casualties, the study and more precise missions, and ... are of interest to many countries, including our country, are unmanned aerial vehicles. Many researchers have been carried out on these devices today. In the same way, our researchers in our country have done a lot of researches on this device in recent years and tried to make these birds with the least cost and with the highest efficiency. This paper also attempts to analyze the flights with the ability to carry the camera. At first, its components, including wings, body, tail, and landing gear, are optimally designed and then aerodynamically and instrumentally analyzed, so that this research used to build these flights species in the future.

]]>Wang Juanjuan and Ping Xueliang

The profile design of cycloid disk in cycloidal steel ball reducer is the core of reducer design, which directly affects the performance of reducer. The cycloidal ball reducer is driven by a certain number of steel balls in a tooth profile composed of a pair of intermeshing internal and external cycloidal lines. The performance of the reducer can be optimized by adjusting the design equation of the cycloidal disc type line. However, in the process of design and optimization, the requirement of freedom and controllability of cycloid is getting higher and higher. The traditional design method of cycloidal profile based on cycloid parameter equation can no longer meet the requirements of design. The NURBS method can accurately represent the free curve and the conic quadratic curve. The cycloidal profile is actually a complex curve composed of a certain number of arcs. In this paper, the NURBS curve is applied to the design of cycloid disk of reducer, and the cycloidal profile based on NURBS is deeply studied. By sampling the known cycloidal profile, the sample point, the inverse control point, the weight factor, the node vector and the sample point are obtained, and the analysis verifies that the error between the fitted NURBS curve and the original curve is within the feasible range. Taking the BR85us-10G-6 reducer as an example, the fitting curve of the inner cycloid disk profile is obtained by using cubic NURBS curve, which can improve the flexibility and local adjustment of the cycloidal disc profile design.

]]>Asep Anwar and Didit Damur Rochman

Company X in 2017 has a delay in the Turning and Milling department of 58% of the total order of 2,334. The actual condition is the number of machines used, namely 5 CNC machines with a production capacity of 230.4 hours / week and the number of work orders from 2013-2018 that must be done is 2767,458 hours. The delay was due to the absence of an appropriate engine scheduling system. Modeling uses mathematical models and runs using lingo software. The results of calculations using LINGO for mathematical models are 14,274 hours with a calculation time of 17 minutes 55 seconds.

]]>Nia Nuraeni Suryaman

An engineer needed the ability to design an experiment research to be effective and efficient to obtain optimal results. The purpose of this experiment is to determine the fastest rate of freezing saline solution. The research process begins with determining the independent variables as much as possible and determines the three independent variables to be tested. After determine variables, and then create table factorial design to determine the research steps as much as 8 times. Then determine the most influential variables using Yates's algorithm was then tested again using response surface methodology (RSM), but for this study only uses two steps of the three step RSM. So it can be concluded that the lower temperature and salinity the faster the rate of freezing for both type of salt, Krosok and salt.

]]>Yani Iriani and Harry Bachtiar

Purpose: The purpose of this study was to determine the maintenance intervals of critical components of jet dyeing machines in an effort to minimize downtime and calculate maintenance costs for engine damage to the jet dyeing. Design/ methodology/ approach: In this study an optimization method was developed to determine the replacement interval of a critical component, namely the Age Replacement Method. Findings: Based on the results of the calculation interval obtained preventive care critical components of jet engines during dyeing 1549 hours. It means that the component must be replaced before operation for 1549 hours or there is 6 times the turnover of prevention under taken in the interval of one year and the resulting decrease in the total cost of 82%. Research limitations/ implications: A review conducted in this paper against one component only, and then it can be developed for this type of component production machines. Practical implications: If the company is implementing a policy of replacement of critical components of the engine on the jet dyeing machine with a method of age replacement, then it will occur treatment cost savings amounting to Rp. 6,752,886 lower when compared with the initial conditions the company previously Rp 37,441,132. Originality/ value: This study combines the Pareto Diagram method and the Age Replacement Method to obtain optimum maintenance scheduling.

]]>Udin Komarudin

Fuel system, type of fuel and type of spark plug, are the determining variables in producing exhaust gas in motorized vehicles. Pollutants produced by motor vehicle emissions include Carbon Monoxide (CO), carbon dioxide (CO_{2}), Sulfur Dioxide (SO_{2}), Nitrogen Monoxide (NOX), Hydrocarbons (HC), Lead Particles (PB), smoke and ash. These pollutants can cause interference in humans, animals, plants and other objects. The study was conducted to determine the effect of the main variables of the fuel system variables (Carburetor and EFI), type of fuel (Premium octane 88 and Pertamax octane 92) and the type of spark plugs (standard spark plugs and spark plugs Iridium) on CO gas exhaust. The test tool used to determine the value of the percentage of vehicle exhaust is a Gas Analyzer and the test vehicle used is a 4-step motorcycle. The research method uses factorial design and variable analysis using Yates's algorithm. The test results show that the effect of the fuel system is -1,272 (Carburetor), the effect of fuel type is -0,268 (Premium), and the type of spark plug is -0,018 (standard spark plug), so the most influential variable on CO gas output is the fuel system using the Carburetor.

Nia Nuraeni Suryaman Udin Komaruddin Arry Hutomo and Martoni

Uniformity of temperature in a room is often encountered in various purposes. This study presents the results of modeling the temperature and airflow in the chicken coop. A problem to be solved in this research is how to design the chicken coop in order to produce temperature uniformity. Thus, the objectives are to build a chicken coop dimensional model of 96x12x2 m with a capacity of 15,500 chicks. Modeling results analysis using CFD (Computational Fluid Dynamics). The stage of completion to meet the above objectives is by measuring the dimensions of the chicken coop. The next data to be obtained are temperature and air velocity to determine the boundary conditions. Some of the above parameters are used to validate chicken coop design. Modeling conducted using CFD methods with temperature and air velocity as boundary conditions. The modeling results showed that the average temperature in the chicken coop is adequate as an ideal temperature standard for chicken coop. Temperature uniformity is obtained by variation of the exhaust opening 4.

]]>Martoni and Marisa Hirary

Experimental studies to see the surface roughness of the turning process have been carried out. The study was conducted to determine the effect of the main variables and the relationship of variables to surface roughness (modeling). The variables carried out were feeding (f), spindle rotation (n) and coolant. Material Specimens use St-37 with cylindrical dimensions. Test specimens were made using conventional lathes, HSS cutting tools and roughness tests were performed with using a Surfcorder (Surface Roughness Measuring Instrument) SE 1700. The research method uses factorial design, variable analysis using Yates's algorithm and modeling using Least Square statistics. The test results show that the most influential variable is feeding, f = 4,957 m, where the biggest roughness occurs at conditions f = 1.2912 m / min, n = 640 rpm and without cooling media. The modeling results show that surface roughness is a function of feeding and velocity, Ra = f (f, n), (Ra = 5.2024 f + 0.0048n), the higher the feeding and speed, the greater the surface roughness.

]]>Saad S. Alrwashdeh

Concentrated solar energy systems are one of the most important applications of solar energy, which will have a promising future in Jordan that because of Jordan has more than 300 sunny days with a high rate of solar radiation. In this research, the phenomenon of blocking and shadowing of mirrors in the solar field and their effect on the production of energy from the solar tower was examined and found that the mirrors far from the solar tower are affected in these phenomena significantly unlike the nearest mirrors.

]]>Afrim Gjelaj Besart Berisha and Fidan Smaili

Application of artificial intelligence in manufacturing process has great impact factor. This work paper is focused into optimization of machining by turning process regarding to the analysing of tool selection (TS), tool path length (TPL) and machining parameters for turning operation using the artificial Intelligence. Except of solving of problems for tool selection and tool path length, here also will be analysed the cutting force (Fc) by turning process whereas as case of research material is steel C45. The results of measurement of the main cutting force Fc, are compared and predicted in theoretical and practical way. Also, all of requirements are fulfilled in regard of the expression. In same time are optimized the main machining parameters regarding to the cutting force with utilization of the Multi-Objective Genetic Algorithm (MOGA). Results for cutting power Pc and Metal removal rate MRR using Pareto Front are obtained using MOGA.

]]>Rasim Alizade

This paper focuses on the systematic type synthesis of parallel robot manipulators by using new structural formulas based on the screw theory. New structural formulas as a total number of screw in kinematic pairs , number of screws with variable pitch , total number of screws that represent the contact geometry of lower and higher joint elements (t), mobility equation for robot manipulators (M), dimension of the closed loop , motion of end effector of parallel manipulator , number degree of freedom of kinematic pairs , refers to find the kinematic structure of robot manipulators realizing a specified motion requirement. Twenty kinematic pairs with structural parameters are introduced. History of six structural formulas using for structural synthesis of parallel robot manipulators from space and different subspaces are presented as a table with equations, authors, years and some commentaries. The structural synthesis approach is based on the elementary notions of screw theory. Using the proposed of structural formulas approach, families of platform manipulators are constructed from a set of structural units. This paper is appropriate for engineers with interest in robotics, rovers, space docking parallel manipulators and screw theory.

]]>Rafat F. Al-Waked and Mohammad S. Nasif

Membrane heat exchanger is one of the main components of green HVAC systems. Performance of a thin-membrane heat exchanger has been examined for different membrane materials. A computational fluid dynamics (CFD) approach was utilized to conduct the current study. The CFD model consisted of a single channel for hot stream and another channel for cold stream. Four membranes were investigated: 45 gsm and 60 gsm Kraft paper, modified cellulose acetate membrane and PVA/LiCl blend membrane. Obtained values of thermal effectiveness at typical HVAC system conditions showed that different membrane materials produced different thermal performance values. The amount of energy recovered from the modified cellulose acetate membrane heat exchanger was the highest. Finally, heat exchanger performance is found to be very sensitive to ambient air relative humidity variation.

]]>Ivaylo Bakalov

Engine simulators are used to achieve the critical educational objectives in training the ship's crew. The simulators provide a complete scientific insight into systems, engines, machinery and everyday operation, as well as detection and fixing of problems. In addition, engine room simulators help teamwork, adaptation to different situations, and decision-making in a crisis situation. An exercise for seafarers was developed in a virtual LNG Carrier with Steam Turbine as main engine in the ERS TehSim 5000 simulation complex. The participants are divided into different teams: - for engine room team, and technical team. The exercise was developed on the basis of the ability of the marine engineers' training complex and the LNG Carrier vessel model on the simulator. The exercise consisted of work on the ship's steam system on LNG Carrier mixed with a real failure on the steam line. The engine room team operates on the simulated complex, and the technical team is dealing with the real work until troubleshooting. The exercise consists of: work on a real check list to start the power system; alarm sound; real work on the problem; implementation of emergency response procedures. The working staffs of the exercise are Greek students – fourth year mechanics, with experience of LNG Carrier.

]]>Bachir Redjel and Sihem Achouri

In this paper, an experimental characterization of fatigue behaviour on prismatic specimens of a symmetrical laminated composite material perlon- glass- acrylique 2P-2V-2P for orthopaedic use is conducted. Cyclic repeated solicitation is employed corresponding to applied minimum stress σmin equal zero. The various loading levels imposed on the specimens are 80%, 70%, 60%, 55%, 45%, 35% and 25% of the value of the static failure strength measured in flexure. A significant scatter characterizes the results of material fatigue lifetime. That is the consequence of the heterogeneity of the material structure. The scattered phenomenon prevents any prediction of the lifetime with a good probability using Wohler equation. This enables defining a constant degradation rate by 10% cycle decade. The microstructure morphology study through microscopic observations is also discussed and analyzed. The damage state in fatigue is characterized by a combination of density and orientation of micro-cracks. This damage is mainly due to mechanisms complexity of matrix micro-cracking, inter facial exfoliation, debonding and delamination. The damage evolution stages in the case of cyclic loading have the same nature than those found in static loading but have different chronology and scale.

]]>I. Asfour D. Rached Ababou Girard soraya and Sébilleau Didier

We have studied the structural, electronic, elastic, magnetic and Thermodynamic properties of Co-based full-Heusler alloys Co_{2}TiSi and Co_{2}TiGe. have been studied by first-principles full-potential linearized augmented plane wave (FPLAPW) method with the Generalized Gradient Approximation (GGA) based on density functional theory (DFT). This shows that the magnetic properties of the compound are dependent on electron concentration of main group element and all compunds are magnetic in their equilibrium L2_{1} structure. The electronic structure report that, our compounds have half-metallic (HM) nature. The mechanical results show that these compounds are mechanically stable. and exhibit 100% spin polarization at the Fermi level where it can be shifted within the energy-gap. In addition, the quasi-harmonic Debye model is applied to determine the thermal properties of the alloy.

Skubov D. Yu. Privalova O. V. and Shtukin L. V.

Recent time the development and achievement of micro- and nano-electromechanical systems (MEMS and NEMS) are appeal the great interest of physics, biologists, engineers-electricians. The designing of MEMS based on pull-in effect consists in interaction of electrostatic field with thin elastic conductive beam. This interaction leads to pull-in instability – the effect of collapse of two initially parallel conductive layers, which play the role of capacitor. The important significance of MEMS have been acquired [1, 2] such, for example, as micro-switches with forward or rotary movement. These devices may be membrane else cantilever or another type, also high speed rotational actuator – contactless micro-gyroscope.

]]>Mohammed D. Salman Kadim Karim Mohsen and Aiman Basem Abttan

This paper concentrated about the effect of both the pseudorandom or random vibration (wind waves) and aerodynamic forces on the wing of unmanned aerial vehicle, which brought the attention of specialists in this field during last years, the performance of wing is improved on a definitive solution for the vibration problems which cause failure in the wings of UAV. The distribution of stresses and distortions with aerodynamic loads is studied. Factors such as tension, pressure and shear stress showed on wing of UAVs due to vibration which caused the structure of wing to break down and then failure. The experimental study was carried out by using wing made of composite material (foam and cover by lamination plate), where airfoil type (NACA Clark y) installed inside wind tunnel of low velocity. It is found that the vibration acceleration at constant wind velocity with variation of attack angle of the wing, it is obtained the relationship between the acceleration and the frequency using the LABVEIW program which analyzed and identified the distribution of forces on the wing. The stress concentration areas is created and found under failure occurs, the aerodynamic force, torsion torque and magnitude of deformation is calculated. It is concluded that the close areas from the root wing (fixed end) is most likely to collapse or break.

]]>Lidija Joleska Bureska

The good working condition of the mills is very important for boilers, which use coal dust. The mills are very important for Power Plants because their work have a direct influence on the combustion process in the boiler furnace. On time controlling the mills condition and their correct repairing during a revision in accordance, technical standards enable unhindered work of the mills with a maximal load. Depending on the coal quality, a maximal load of the mills directly enables increasing of the heat in the boiler. In continue of the paper are shown the characteristic, parameters and capacity of the fans mills during tests: before overhaul (with current maintenance, with partial reparation with a lot of shortcomings) and after overhaul (with complete reparation). According to the received results, a comparative analyze was made for the effect of the mills' condition on the capacity of the boiler and of course of the Power Plant. In order to reach better characteristics of the mills, at the end of paper are mentioned measures for increasing mills‘ capacity for 20t/h with execution technically properly overhaul, with elimination on all gaps in the mills, with improving sealing on the whole coal line etc.

]]>Edilson Gomes de Lima

This paper traced an introductory script about the natural communication by an interface between the tissues and the environment theoretically, as a possible form of biological adaptation in environment, as a first step for popularization in tissue engineering for mechanical and chemical engineers. Knowing the keys communication system, it’s theoretically possible to understand that even after generating a specialized tissue, it is still possible to induce new stem cells to generate tissues. According to external and internal tissues readings, as by integrin mechanism, or actomyosin induced by various means, presented throughout this study. Also, make visible and clear new stem cells induction techniques through stimuli, activated by means for the formation of specialized and interconnected specialized cells for tissue engineering. In this objective investigation is showed some mechanical analytical apparatus in new designs to automate biological processes. The domain of all flow and mechanism in stem cell activation triggers is as important as the knowledge of DNA sequencing. With the focus on proving the ability of the tissues to read passively, interpret the external environment and make changes by biochemicals for appropriate adaptation, the genes interpret the environmental stimuli, human senses interfaces and activate adult stem cell niches. External factors along the stem cell are the focus of this investigation, e.g. it has already been proven that a specific nanotopography is a platform to induce differentiation control in stem cells. By nanotopography a stem cell can being induced to become a specific tissue. Through the control and listing these activation keys through mechanical engineering and logic, we can create true artificial tissue factories in high precision innovative scaffolds geometries, with final objective new addictive manufacture and innovative architecture for biological circuits.

]]>Kanat Amirtayev

A universal algorithm for solving applied tasks of thermo elastic state of a partially heat insulated rod of limited length, in the presence of axial force, temperature, heat flow and heat exchange, was developed. The corresponding numerical calculation of efforts of the rod partially thermally insulated and clamped by two ends, in the presence of heat flow was elaborated. The numerical algorithm allowed calculate the lengthening value of the partially thermally insulated rod or the compressive stress and strain in the rods of limited length with the heat flow, the heat exchange, heat insulation and the axial tensile force.

]]>Anatoli Chigarev and Ju. Chigarev

In the article on the principles of Fermet, Huygens obtaine the differential equations in the form of Hamilton, which describe the ray trajectories and wave fronts in inhomogeneous media. Established that the vector of Poynting-Umov's determining the direction of energy propagation in inhomogeneous medium is coincident with the vector tangent to the ray. In the second part of the article established that the equations of the theory of rays' propagation in inhomogeneous media have the form of equations of nonlinear dynamics and describe the emergence of deterministic chaos in the geometry of rays for a wide variety of types of heterogeneous structures. In this case, the rays behave randomly and their description you must go to the description based on the theory of random functions and fields. In the third part of the paper is considered a model which is equivalent to the random medium and the calculation of the coordinates of the ray (the mathematical expectation and correlation functions). Understanding of these characteristics gives information about the behavior of the trajectories of the rays for these models of media. The description of the behavior of rays on the basis of the equations of statistical mechanics is discussed in the article for functions of Markov's type.

]]>Firas M. Hasan and Maathe Abdulwahed Theeb

Cool thermal energy storage using thermal stratification becomes one of the widespread applications because of the ability to shift the electrical cooling loads from on-peak to off-peak periods and significantly contributes to reducing the capacity of the refrigeration system and operating costs. Seven flow rate tests varying from 1.5 to 7.5 l/min for charging cycle were performed on small-scale vertical cylindrical storage tank equipped with three primary inlet diffusers, an elbow, two-ring linear and radial circular diffusers. The storage tank with inlet diffusers was assessed using temperature distributions and performance measures including thermocline thickness(ht), the half-cycle figure of merit () and equivalent lost tank height (ELH). Commercial finite volume code was used to predict temperature distributions in a stratified water tank model, temperature data acquired from experimental tests and simulation models were compared for validation purpose. The results suggested that the storage tank with two-ring linear circular diffuser produced better performance and higher stratification than two-ring radial circular diffuser for various flow rates by 1.4% , 20.6% ELH and 10.6% ht, and much better than an elbow diffuser by 1.7% , 24% ELH and 31.1% ht, furthermore, the degree of mixing was affected essentially the flow velocity which in turn causes an increase or decrease in thermocline thickness. Temperature distributions obtained from finite volume model are found to be in very close agreement with those obtained experimentally.

]]>Amir Haghighatkhah Hossein Ahmadi-Danesh-Ashtiani and Kourosh Amiraslani

In this study, nanofluid flow inside a triangular channel in the presence of a magnetic field with two phase model was analyzed. For this purpose, the external surface of the channel is heated or cooled with a specific heat transfer coefficient, and the effect of the changes in the Nusselt number as well as the pressure drop for variable parameters such as nanoparticle concentrations, magnetic field strength, and channel shape (relative to the circular mode) was investigated. In order to the Grid Independent Study, the Nusselt number for different sizes of grid has been evaluated. As a result, comparing the Nusselt number changes, the average is seen by changing the size of the networking. A grading with the number of 350,000 elements is suitable for simulating the corresponding problem. In order to confirm the validity of the results, simulation of Nusselt number changes during the channel was evaluated and compared with the results presented by Saeed et al. [23]. The error rate between the data presented in reference [23] and the simulation claims is not tangible, and therefore the model used for simulation has been approved. In this study, a triangular channel with a flow inside it is a nanofluid, is analyzed in the presence of a magnetic field in a smooth, completely two phases. For this purpose, the external surface of the channel with a certain heat transfer coefficient and the effect of changes in the thermal and fluid parameters with the change in the parameters involved in the problem have been observed. The results show that with increasing magnetic field, friction coefficient, in-channel velocity, heat transfer rate, average Nusselt number increase. In this study, for simulation we used computational fluid dynamics and limited volume method, and specifically using the Ansys-Fluent version 17 software. The problem is investigated in the form of a three dimensional, stable, single-phase and two-phase flow.

]]>Fatih Cemal Can Önder Lapçin Burak Ayan and Mehmet Çevik

This paper represents a Human Machine Interface (HMI) design to control a 3 DoF robot manipulator. This manipulator has two parallelograms to make the moving platform always parallel to the ground. We used inverse kinematic analysis of the robot manipulator to control the end point location. Inverse kinematic results are verified using design parameters and end effector location. According to our algorithm, user defines the end point location from HMI, and then program solves inverse kinematics of the robot manipulator. The angles are sent to Arduino microcontroller to set the position of the servo motors. Using this HMI, the user picks and places the object in real time. The user can also give command to draw linear, circular and rectangular paths on the HMI.

]]>Volodymyr Gursky Igor Kuzio and Vitaliy Korendiy

The problems of synthesis and substantiation of elasticity parameters of the resonant vibratory device with electromagnetic drive and one flat spring are considered. At first, the harmonic systems with oscillation frequencies of 50 Hz and 100 Hz were investigated. Then, various asymmetric piecewise linear characteristics of elasticity were carried into effect on one flat spring using auxiliary intermediary fixed cylindrical supports. Due to this, the corresponding vibro-impact operation modes were obtained. The resonant systems characterized by improved functioning efficiency were carried into effect using the new technique of optimization synthesis of elasticity parameters. The resonant systems being investigated were implemented in practice. The basic experimental investigations of their kinematic, dynamic and energetic parameters were carried out. The fundamental result of the investigation consists in confirmation of the improved dynamic efficiency of vibro-impact systems with pulsed electromagnetic excitation designed according to the new technique. The proposed systems may be used in technological processes of materials compaction and screening, of surface treatment of machine parts and in processes associated with nanotechnology.

]]>I. Asfour and D. Rached

We present an ab-initio study of the structural, electronic, elastic, magnetic, thermal and thermodynamic property of the quaternary Heusler alloys (x = 0, 0.25, 0.5, 0.75, 1) with the linearized augmented plane wave method based on density functional theory (DFT) and implemented in WIEN2k code. For exchange correlation potential we have used the generalized gradient approximation (GGA) of Perdew et al. Our results provide a theoretical study for the mixed Heusler in which no experimental or theoretical data are currently available. In their equilibrium L2_{1} structure, all concentrations are equilibrium L2_{1} structure; all concentrations are magnetic and metallic. However, there is linear variation of the lattice parameter. The bulk modulus, the elastic constants and the Debye temperature was studied with variation of composition x of Ge. A regular solution model is used to investigate the thermodynamic stability of the alloy which is essentially shows a miscibility gap phase by calculating the critical temperatures of the alloys. In addition, the quasi-harmonic Debye model is applied to determine the thermal properties of the alloy.

Anatoli Chigarev Victor Polenov and Pavel Shirvel

A theoretical study of seismic waves propagation in a soil layer with a free surface has a great importance for a prediction in engineering decisions. Wave packets are radiated from an earthquake source and transfer energy. A transformation and a selection of wave packets occur in a process of wave propagating that why waves which arrive in a layer have a length considerably greater than a variation scale of heterogeneity in a medium in a layer near free surface. In the case, when the properties of different layers affect a relatively small degree on a behavior of the waves, an approximation of effective medium gives a fairly good solution. A model of a hypoplastic medium is used for a describing of some effects, which are observed in the time of seismic wave propagation. The model of hypoplastic medium allows describing many effects which are observed in granular soils. We consider a successive application of effective medium and ray methods in order to receive of approximate analytical solutions wishing to describe shear wave propagation in stratified layer, which lies on a half-space.

]]>M. A. H. Hayder I. Goktepeli S. Yagmur M. Ozgoren F. Kose and L. A. Kavurmacioglu

Defense applications for both under oceans and seas, particularly underwater vehicles have been considered in this research. With this aim, flow characteristics around a torpedo-like geometry under the effect of the boundary layer flow over a smooth flat plate have been experimentally examined by using PIV technique. All of the experiments have been done for Re=20000 and Re=40000 based on the length (L) of the geometry as a characteristic length. As a result, time-averaged streamwise velocity components , velocity vectors , streamline topologies <ψ> and Reynolds stress correlations in the wake region of the torpedo-like geometry have been acquired in the range of 0 ≤ G/D ≤ 1.5. Here, G is the space between the bottom point of the geometry and flat plate surface; D stands for the diameter of the geometry. It is found that at the smallest value of G/D=0.25, jet-like flow occurs between the plate and the model which causes a powerful scouring. As the gap ratio is increased to G/D=0.5 and G/D=1.0, the jet-like flow diminishes slightly and then the flow structure in the wake region becomes similar to the uniform incoming flow condition for G/D=1.50. Due to the effect of the jet-like flow and boundary layer flow, time-averaged flow patterns present asymmetrical distributions which are clearly shown a bigger size focus close to the plate in streamline topology. Reynolds stress patterns form more powerful viscous forces in the boundary layer flow due to the occurrence of eddy vortices and viscosity effect. It is observed from the aforementioned flow patterns that interaction between the flow structure, the model and boundary layer flow yields very complex structure. In order to decrease the energetic flow in this condition, passive or active flow control method can be integrated on the torpedo-like geometry.

]]>A. M. Formalskii

We consider here mechanical objects that have desired operating regime unstable without additional control signal. The resources of control are assumed limited. First of all the motion equations of a multi-link pendulum mounted on a moving base – wheel are designed. Equations that describe only the pendulum motion are separated. The problem of controlling a single inverted pendulum on a wheel is studied. Control law that ensures large basin of attraction of the top unstable equilibrium is developed. The 'inverse' system – the inertia wheel pendulum with fixed suspension point is investigated. For this system the control algorithm is developed to stabilize globally the top equilibrium of the pendulum. This control law is tested successfully in simulation and experiments. The double pendulum with fixed suspension point is considered. The limited in absolute value control torque is applied in the inter-link joint. The control algorithm to ensure global stabilization of the inverted pendulum is designed. For maximizing basin of attraction of unstable system, we use all control resources to suppress the unstable modes. At the end of the paper, the problem of gyroscopic stabilizing of the upright unstable position of a robot-bicycle is studied.

]]>Nimmy Thomas and Manoj T. Issac

Hydrodynamic analysis of tow cable has an important role in the design of towed system. Cable catenary, cable depth attained for a given cable length, cable tension and angle of cable with the body are the parameters that affects the towed system related to tow cable. This paper deals with analysis of a set of commercially available cables of different properties using Orcaflex software. The cables were analysed for different payouts at different speeds. A comparative study was performed on the results obtained relating the cable properties (diameter and buoyancy). This provides a rough idea on the catenary profiles that reflects the depth and trail achieved by the cable given payout and speed.

]]>Madan A. D and Manoj T. Issac

The prediction of hydrodynamic performance of AUV is essential during the early stages of design for the efficient modeling of the AUV. This paper discusses the use of semi-empirical equations developed for airship hulls by various researchers in the field of aerodynamics, on the axisymmetric AUV bare hull at different angles of attack. Three hulls of varying length-to-diameter (L/D) ratios are selected for the study. The results obtained from the semi-empirical equations are compared with the available experimental results and also with the results obtained from the numerical analysis carried out using the CFD code – STAR CCM+.

]]>Zone-Ching Lin Hao-Yang Ding and Po-Yen Chen

This article studies the change of specific down force energy and cutting depth of sapphire substrate when sapphire substrates were dipped in different temperatures of slurry. It involved applying small down force in cutting sapphire substrates by atomic force microscope (AFM) before dipping them in slurry in order to obtain the SDFE value of without dipping slurry. Next, small down force was applied to cut sapphire substrates dipped in slurry for varying dipping temperatures to obtain the SDFE_{reaction} values of dipping slurry with different dipping temperatures. Nanocutting was performed by AFM with a small constant down force to obtain the cutting depths of sapphire substrate for the different dipping temperatures of slurry. The results of this study indicated that the dipping temperature of slurry increased, the SDFE_{reaction} value of sapphire substrate decreased and the cutting depth of sapphire substrate with a constant down force increased.

Ayadi Aicha and Khalfallah Omar

The Al_{2}O_{3} and AlN materials are often used as electrical insulators (electronic substrates) also the case of pressure sensors where the aluminum nitride (AlN) is selected as the piezoelectric layer and the alumina (Al_{2}O_{3}) as a solid substrate insulating. This study aims to investigate the mobility of dislocations near the heterophase interface of bimaterials based alumina (Al_{2}O_{3}) under the effect of the image force, without the effect of temperature, deformation and external stress These dislocations having a Burgers vector b = 1/3 , they are located in Al_{2}O_{3}. The interface is defined by its plane parallel to the dislocation line and disorientation varies between 0 and 180^{。} around the axis . Usually, the image force calculated in the context of the anisotropic linear elasticity using Barnett and Lothe theory with Stroh formalism, Fi = ΔE / d, where ΔE is the elastic interaction energy. The results show that dislocation motion under the image force effect depends on the elastic and crystallographic properties of the materials constituting the bicrystals and even disorientation of the interface which has an effect on the intensity of the elastic interaction energy. The dislocations are repelled to the interface if the difference in shear modulus between the two materials is positive (Δμ= μ_{2} − μ_{1}>0), they are attracted to the interface in the opposite case (Δμ= μ_{2} − μ_{1}<0).

Rafat Al-Waked Nathan Groenhout Lester Partridge and Mohammad Nasif

Carparks are constructed to provide a certain number of car spaces for visitors, shoppers and/or clients of a commercial facility. The required ventilation system design is generally based on local standards provided by local authorities. The purpose of the current study is to develop a performance based ventilation system for a shopping center carpark. The aim of the study is to undertake computational fluid dynamic (CFD) modelling of the carpark to determine the potential minimum ventilation exhaust rate levels. Results showed that the proposed carpark exhaust system was considered acceptable and no modifications were required. The CO concentration levels in all areas, except within the immediate vicinity of car exhaust plumes, were below 100 ppm. The average predicted CO rise was less than 25 ppm across the carpark which is in compliance with the current Worksafe Australia and WHO CO exposure limits. Moreover, results indicated that the 64,000 l/s exhaust air flowrate was sufficient, and could be reduced to 50,000 l/s. From a financial point of view, it was concluded that the removal of the outlet grilles located at the Southern wall of the Commuters section of the carpark was an acceptable alternative. This cost saving is based on the potential deletion of a fan system, plenum arrangement and shaft which are required as part of the deemed-to-satisfy system design.

]]>John P.T. Mo and Daniel Chan

Wind power generation is an effective form of clean, renewable energy which operates both on land and offshore. The primary means of converting wind to power is by wind turbines. The issue with wind turbines is high uncertainty of operating environment resulting in low life cycle reliability. Frequent breakdown failures resulting in reactive maintenance is costly which results in downtime and loss of production. FMEA has been used in some cases to develop maintenance schedule but the effect is minimal. This paper investigates a new method of determining faults from adverse operating conditions by bond graph model and combines with the concept of failure mode and effects analysis to simulate the effects of maintenance strategies on the mean time to failure of wind turbine components. The mean time to failure data can then be used to refine the maintenance task with additional inspections and replacements that can prevent breakdown failures and maximize the utilization rate of expensive components.

]]>Yusuke Saito and Tatsuo Sawada

Free surface movement of water in a rotating, laterally oscillating cylindrical container was qualitatively investigated. Time-dependent dynamic pressure was measured instead of free surface displacement. The swirling direction was determined by forcing the frequency and rotating direction of the cylindrical container. The swirling direction was opposite to that of the rotating cylindrical container when the forcing frequency was low, whereas the crest of the free surface swirled in the same direction as that of the rotating cylindrical container when the forcing frequency greatly increased. Unstable swirling occurred when swirling direction changes, but it disappeared as the rotating frequency increased.

]]>Emilia Abadjieva and Valentin Abadjiev

The study illustrates the mathematical models, applied to the synthesis of hyperboloid gear drives. The kinematic approach for registration and elimination singularity from the vicinity of the pitch contact point at the mesh region of the synthesized spatial transmissions is shown. Analytical dependencies are illustrated in order to provide the definition and control of the singularity of first order on the conjugated active tooth surfaces, when hyperboloid gear sets are synthesized by applying two approaches for their synthesis: "synthesis upon a pitch contact point" and "synthesis upon region of mesh".

]]>Joseph C. Chen and Naga Hrushikesh R Narala

The latest globalization trends resulted in increasingly interdependent economies of nations and multinational firms. This may leave companies operating internationally at the mercy of the volatility in currency exchange rates. Forecasting these exchange rates became very important in international trade and commerce, as it involves key decisions of foreign investment, forward contracts and expanding business to new horizons. This research paper describes a Feedforward Backpropagation Neural Network (FBNN) model and its application to currency exchange rate forecasting. A study of FBNN model is conducted for forecasting exchange rates between Indian rupee and US dollar, based on previous data of inflation, real interest rates, gross domestic product (GDP), current account balances, government budget balances and debts of both countries. The weights used in neural networks were optimized using gradient descent and backpropagation method. Models with different hidden neuron layers were developed by comparing the actual exchange rates with forecasted monthly exchange rates from January 2001 to December 2014. The most effective model was then used to simulate exchange rates for the year 2015. The FBNN model with ten neurons in the hidden layer has the least Mean average percentage error (MAPE) value of 1.32% and is considered to be most impressive model.

]]>Chih-Cheng Yang and His-Cheng Liu

Self-drilling tapping screws are widely used for construction works. In order to increase the strength and improve the wear resistance without affecting the soft, tough interior of the screws in self-drilling operation, a case-hardening treatment is an essential process. Carbonitriding primarily provides a needed hard, wear-resistant case of screws. In order to improve the qualities of AISI 1016 self-drilling tapping screws, a series of carbonitriding experiment is conducted in a continuous furnace. Various parameters affect the quality of carbonitriding such as quenching temperature, carbonitriding time, atmosphere composition and tempering temperature. The effects of carbonitriding parameters affected the quality characteristics, such as case hardness and core hardness of self-drilling tapping screws are analyzed by Taguchi method. It is experimentally revealed that the carbonitriding time and tempering temperature are the significant factors for both case hardness and core hardness. The optimum mean case hardness is 625.5HV, and the optimum mean core hardness is 368.7HV. With the optimum conditions, the carbonitriding treatment is capable of producing good self-drilling tapping screws. The results presented in this paper could be used as a reference for fastener manufacturers.

]]>Kazumi Komatsu Akihiro Naganawa Yoshinori Ueno Emilia Abadjieva and Hisashi Ito

Ultrasonic motors of various drive principles have been developed, but it is difficult to downsized most of them. Hence, an ultrasonic motor which combines a PZT with a metallic plate, which can be downsized easily, is developed by the authors. So far, the studies are focused on the ultrasonic motor with a flat-type metallic plate. In this study, it is tested an ultrasonic motor incorporating a curve-shaped metallic plate, in order to improve performance.

]]>Ugochukwu Kenneth Udeze and ChinwubaVictor Ossia

This study involved using typical Joint North Sea Wave Project (JONSWAP) based Umbilical design of lengths 3044m, 3215m, 4481m and 2873m clamped to Floating Production Storage and Offloading (FPSO) unit in Deep Offshore Nigeria at water depth of 2000m. Relevant metOcean data was used to simulate the environmental conditions. The process was simulated using different wave spectra on OrcaFlex software. JONSWAP spectra results for Umbilical-1 to Umbilical-4 at near-surface current (End A: 850m) showed a Transverse Vortex Force (TVF) range of 0.0115 – 0.018kN/m; 0.009 – 0.0149kN/m; 0.006-0.014kN/m; 0.0048 -0.009kN/m, respectively. For Ochi-Hubble spectra, the corresponding TVF range obtained include: 0.004 - 0.0305kN/m; 0.004 - 0.028kN/m; 0.003 - 0.027kN/m; 0.003 - 0.0232kN/m, respectively. JONSWAP spectra showed maxima (t, TVF) values of (0.013, 0.018); (0.012, 0.0149); (0.008, 0.014); (0.0074, 0.009) from Umbilical-1 to Umbilical-4, respectively. With the Ochi-Hubble spectra, maxima (t, TVF) values were (0.018, 0.0305); (0.016, 0.028); (0.013, 0.027); (0.0141, 0.0232) for Umbilical-1 to Umbilical-4, respectively. Hence, maxima (t, TVF) values were greater for Ochi-Hubble than JONSWAP. Simulation plots indicate that adjusting the peakedness parameter (γ) of the JONSWAP spectra does not give the required accuracy for this region. Therefore, using a JONSWAP based Umbilical design in Ochi-Hubble environment like Offshore Nigeria shows higher vortex induced vibration (VIV) at near surfaces leading to higher TVF, and higher fatigue damage tendency.

]]>Rajat Sharma and Ankur Geete

This research work is concerned with comparative experimental analyses performed on parabolic solar collector. It presents the experimental analyses on parabolic solar collector at various operating conditions. For this experimental work, parabolic solar collector was fabricated. Various comparisons have been done between mirror concentrator and aluminium sheet concentrator. Experimental readings have been taken at 12:30 PM and at 01:30 PM and then performance of the solar collector has been found. For performance analyses, different pipe materials have been selected like copper pipe, aluminium pipe, brass pipe and mild steel pipe as receiver pipes. And different fluids have been selected for analyses like water and antifreeze ethylene glycol (coolant) as working fluids. Flowing fluids outlet temperatures, heat transfer rates and instantaneous efficiencies have been found at various operating conditions and then best operating condition for solar collector has been identified. This experimental research work can be concluded as up to 92% instantaneous efficiency and 12.2℃ temperature difference between inlet-outlet temperatures are achieved with aluminium sheet collector but 1208.99 W heat transfer rate is found through mirror collector with copper pipe and coolant. After all experiments, calculations and graphs have been plotted, concluded that overall performance of fabricated solar collector with the aluminum sheet collector, copper pipe and coolant is the best.

]]>Younghun Pyo Kyunghyun Lee and Kwanho You

In this paper, we propose an epicenter measurement using a laser interferometer. The laser interferometer system is an equipment with its extraordinary accurate capability for displacement measurement. The seismic signal is measured in the observation as P-wave and S-wave form. The seismic signal is indicated as in a form of intensity signal which is represented as a trigonometrical function using the heterodyne laser interferomter. The epicenter can be derived by P-S time which can be determined by intensity signal. With a range difference of arrival (RDOA) method, we can estimate the epicenter location from the distance data between the epicenter and the observatory. We suggest a recursive least square (RLS) algorithm to obtain a solution that minimizes estimation error value. Through some simulations, we prove the performance of the proposed method.

]]>Kyunghyun Lee Hyungkwan Kwon and Kwanho You

Recently, multi-robot systems are emerging in various industries. The multi-robot systems have several advantages in comparison with a single-robot system. The task of single-robot system is limited, because a bigger robot is required to perform more multiple functions. However, multi-robot systems can distribute the functions to each robot. The localization problem is essential for realization and it becomes more important in the multi-robot system. The multi-robot system needs to work maintaining a formation. In order to accomplish the given mission in the demanded formation, the localization is important. For multi-robot localization, we use the relative position to find robots' position based on odometry sensor, and the iterative Kalman filter algorithm is utilized to estimate the accurate position.

]]>Chia-Yi Yeh (Jia-Yi Yeh)

Vibration analysis of polar orthotropic sandwich annular plate with magnetorheological (MR) elastomer is considered. The effects of thickness of the MR elastomer, applied magnetic fields on the sandwich system are discussed. The characteristics of the sandwich plate system can be controlled and changed by the applied magnetic fields. The core layer of MR elastomer has significant effects on the damping behavior of the sandwich plate system according to the numerical results.

]]>Marcelo Matos Martins José Divo Bressan and Sérgio Tonini Button

Computational numerical simulation has been largely applied in the design and analysis of metal forming processes. Extrusion is one of the main forming processes largely applied in the manufacturing of metallic products or parts. Historically, the Finite Element Method (FEM) has been applied for decades in metal extrusion analysis. However, recently in the academy, there is a trend to use the Finite Volume Method (FVM), because literature suggests that metal flow by extrusion can be analyzed by the flow formulation. Thus, metal flow can be modelled as an incompressible viscous fluid. The MacCormack Method is commonly used to simulate compressible fluid flow by the FVM. However, metal extrusion does not present state equations to calculate the pressure, and therefore, a velocity-pressure coupling method is necessary to obtain consistent velocity and pressure fields. This work proposes a new numerical scheme to obtain information about metal flow in the extrusion process along the steady state. The governing equations were discretized by FVM, using the Explicit MacCormack Method to structured and collocated mesh. The SIMPLE Method was applied to attain pressure-velocity coupling. This new numerical scheme was applied to analyze forward extrusion of lead. The metal extrusion velocity fields were calculated with a fast convergence and presented a good agreement with analytical and experimental results obtained from literature.

]]>Ahmad Muammar Bin Md Yasin Lim Wei Liong Patrick S.K. Chua and Zheng Jianxin

This paper presents a new novel design of a smart walker for rehabilitation purpose by patients in hospitals and rehabilitation centers. The design features a full frame walker that provides secured and stable support while being foldable and compact. It also has smart features such as telecommunication and patient activity monitoring.

]]>Yi-Jhen Li Jian-Shiang Chen and Chuan Yang

In this article, the author aimed to design a lower limb orthosis for the person whose lower limb can emerge the normal electromyography. According to the motion intention method, use the electromyography signal and upper limb angle as the trigger signals of motion. The lower limb electromyography signal is processed by linear envelope method, and the signals are sent to the controller. The system uses PI current feedback control to give the wearer's knee appropriate aids. This orthosis is an exoskeleton with four flat EC motors as the actuators mounted on the outer of the wearer's both knees and hips, besides, uses a battery as the power source. While motor rotating, motor sends the torque to the wearer, therefore, the wearer can reduce forces applied while sitting or standing, and reach the aid purpose.

]]>Felix T.S. Chan C.S. Wong and S.H. Chung

In the literature, preventive maintenance (PM) tasks are treated as one category of work such that they were interchangeable in scheduling. It is not practical in the real production system as different categories of maintenance tasks should be independent. Thus, this work modeled a new Production-Maintenance Scheduling (PMS) problem that considered different categories of maintenance with different maintenance intervals and durations. To solve the new problem, we developed a genetic algorithms approach named the Second Generation of Genetic Algorithms with Dominant Gene (GADGII). The numerical results showed that the proposed GADGII outperforms the traditional GADG with shorter makespans.

]]>A. Abdul-Ameer

A single shaft dual turbine drive, for a marine propulsion system, is considered. Distributed-lumped analysis is used in the dynamic response prediction. This enables the relatively concentrated assemblies to be included as lumped, point-wise representations. The propulsion shaft is incorporated as a dispersed inertia and stiffness model. Multivariable, least effort regulation is employed to achieve the control required. The performance of the closed-loop system following reference input and load disturbance changes is evaluated and the drive shaft speed and twist angle response transients are computed.

]]>Wen Liang Chang and Mei Wei Wang

This paper studies the comparisons of individual and group replacement policies for a two-machine series system. Suppose that manufacturer's production system which consists of two machines in series. For two machines, when any machine fails within the operating time, minimal repair is performed for machines by the manufacturer. Due to the inevitable deterioration of the machine, the machine may fail more frequently as its age or usage increases. Therefore, an appropriate preventive replacement (PR) of the machine may be suitable for reducing the number of failures and maintains the operation of the machine normally. When a PR action is performed, it incurs a replacement cost and a downtime cost. Hence, when the replacement cost is high, it might be worthwhile replacing both machines at the same time (called group replacement policy; GRP) instead of replacing them separately (called individual replacement policy; IRP). Under these maintenance policies, the maintenance cost rate models of individual and group replacement for a series system is derived and further, optimal preventive replacement time is obtained such that the expected total cost rate is minimized. Finally, some numerical examples are given to illustrate the influences of individual and group replacement policies to the expected total cost rate.

]]>Han-Taw Chen and Chung-Yi Wu

This study uses an inverse method and commercial package FLUENT along with the experimental data to obtain heat transfer and fluid flow characteristics of plate-fin heat sinks placed in a rectangular enclosure with two openings. A cooling fan placed on the top of the fins is blown downward. Another fan is placed on the outside of the opening in order to extract the air inside the enclosure. The inverse method along with the experimental temperature data is applied to estimate the heat transfer coefficient on the fins. Afterward, a commercial package FLUENT along with the zero-equation turbulence model, experimental temperature data and the resulting heat transfer coefficient is used to obtain heat transfer and fluid flow characteristics of plate-fin heat sinks within a rectangular enclosure with openings. The resulting heat transfer coefficient and fin temperature at the selected measurement locations are close to inverse results and the experimental temperature data, respectively. Thus, the zero-equation turbulence model is suitable for this problem.

]]>Suphattra Ketsarapong and Prapapan Ketsarapong

The purpose of this study is to present the Geographic Information System (GIS) that supports land suitability evaluation for the development of target land in Bang Pu Sub-District Municipality in Samut Prakan Province in Thailand in order to promote the concept of the eco-industrial town. GIS was applied as the research methodology. SIEVE analysis was employed to evaluate suitable land. There are four factors involved in evaluating the land in this study. The first factor is the industrial density factor. The second factor is the industrial cluster factor. The third factor is the accessibility to green and recreation areas factor. The last factor is the risk to the urban ecology and environment factor. Each factor has three score levels in descending order: 3, 2, and 1. It was found that suitable target land could be found in five locations. There were 408 industrial factories on the target land (68.92% of 592 Group 3 factories). The findings are important information for the Samut Prakan Provincial Office to select suitable land, to make strategic and master plans, and to manage resources in order to maximize efficiency and develop the province into a model eco-industrial town in accordance with the province's vision.

]]>Alexander Kählert Sebastian Giljohann and Uwe Klingauf

Unplanned aircraft ground times caused by component failures create costs for the operator through delays and reduced aircraft availability. Unscheduled maintenance on the other hand also creates costs for Maintenance, Repair and Overhaul (MRO) companies. The use of PHM is considered to improve the planning of component-specific maintenance and thus reduces consequential costs of unscheduled events on both sides. This study assesses the component-specific costs and characteristics of today's maintenance approach. A discrete event simulation represents all relevant aircraft maintenance processes and dependencies. For this purpose the Event-driven Process Chain (EPC) method and Matlab/SimEvents are used. The data input (process information, empirical data) is provided by a particular MRO company. Whereas recent approaches deal with stochastically processed data only, e.g. failure probabilities, the proposed method mainly uses deterministic data. Empirical data, representing particular dependencies, describes all relevant stages in the component lifecycle. This includes operation, line and component maintenance, troubleshooting, planning and logistics. By simulating different scenarios, various maintenance future states can be evaluated by analysing effects on costs. The obtained economical and technical constraints allow specifying component-level PHM design parameters, as minimum prognostic horizon or accuracy. Detailed process-specific information is provided as well, e.g. costs of non-productive MRO activities or no-fault-found (NFF) characteristics.

]]>Dorin Catana

The paper shows the cutting behavior of the three high-speed steels, which were thermomechanical treated. The performed studies highlight that unconventional treatment (thermomechanical) applied to the high-speed steels improves their technological properties. To benefit from this improvement, the deformation degree applied at studied steel must be up to 70% (ideal between 50-70%). Thermomechanical treated steels were used in the manufacturing of various types of cutting tools, which were subsequently tested in the cutting process. The volume of processed results being great, the paper presents the cutting behavior of the disk-type of milling cutters (disk cutter). Through geometry and shape this type of tool is suitable to be processed by thermomechanical treatment. In tests were used both normal cutting regimes and hard (specific to this steels). The performances of cutting tools made through the thermomechanical treatment are superior to those conventionally manufactured. Specifically, regardless the cutting speed or time, the cutting tools from first category are worn less than those classics.

]]>Sinan Al-Wandi Wencheng Pan Songlin Ding and John P.T. Mo

This paper discussed the 3D finite element modeling (FEM) of the drilling of uni-directional Carbon Fibre Reinforced Plastic (CFRP). Most of the real life parts of CFRP are modeled with single layer shell element and can be modeled as composite by assigning a composite property to it. A Meso-Scale (Laminate Level) approach has been developed to extract displacements, overall stiffness behavior, and detailed stresses and strains. The objective of this study is to implement a ply-based modeling technology to model the laminates and to analyze the interaction mechanisms between the drilling tool and material to validate if the meso-scale approach would be the ideal solution to characterize the drilling induced damage. Results show the model has proved its ability to correctly estimate the thrust force and torque.

]]>Suha K. Shihab and Ethar Mohamed Mahdi Mubarak

In this work, an attempt has been made to analyze the influence of various machining input parameters of CNC end milling process viz. cutting speed, feed rate and depth of cut on machining output variables (surface roughness and material removal rate) during machining complex shape of copper. Three different levels of input parameters were planned as per Taguchi's L_{9} orthogonal array. The parameters are optimised from analysis of mean (ANOM). Analysis of variance (ANOVA) was employed to investigate the effect of machining parameters on the variables. Results of this study indicate that the depth of cut has the most significant effect on R_{a} having percentage contribution of 71.06% followed by feed rate and cutting speed having percentage contribution of 23.22% and 2.12% respectively. For material removal rate, it is observed that the percentage contribution of feed rate is maximum i.e. 68.58% followed by depth of cut and cutting speed having percentage contribution of 22.13% and 7.52% respectively. Also, the results revealed that optimum combination of machining parameters which resulted in optimum value of the surface roughness is A_{3}B_{1}C_{2} i.e. cutting speed of 6000 rpm, feed rate of 500 mm/tooth and depth of Cut of 0.06 mm. Similarly, optimum combination of machining parameters which resulted in optimum value of material removal rate is A_{1},B_{3}C_{3} where the values for cutting speed, feed rate and depth of cut are 2000 rpm, 1500 mm/tooth and 0.08 mm respectively.

Feng-Chin Tsai and Xin-Zhi Huang

Storage-type solar PV/thermal hybrid system added a water tank below the PV panel directly is to cool the surface of PV chip and reuse the waste heat. Solar test equipment was set up to adjust irradiation amount of halogen lamp to light on solar PV board and measure the I-V curves of the PV panel simultaneously. Surface temperature of PV panel and water temperature of water tank are measured respectively by infrared thermal imager and thermocouples. By altering the irradiation of 600~900W/m^{2} at a 30^{°} inclination angle of PV panel, the experience data of storage-type solar PV/thermal hybrid system can be got, total efficiency transformed by photovoltaic efficiency and hot water efficiency of PV/thermal hybrid system can be analyzed. The results show that total efficiency of storage-type solar PV/thermal hybrid system is more excellent as compared to the pure photovoltaic efficiency. The hot water efficiency of PV/thermal hybrid system from recycling waste heat gets 38~40%. If the electric/heat energy conversion efficiency is about 0.38, total efficiency transformed obtains more efficiency about 14~15% from the recycling the waste heat. The total efficiency of storage-type solar PV/thermal hybrid system is almost 4 times than photovoltaic efficiency in experimental surrounding.

M. Endo W. Takaki D. Nishioka Y. Hirakata A. Kawahara and M. Sadatomi

This paper describes the experimental study on the effects of grid spacer with mixing-vane (MV) on gas-liquid two-phase annular flow in a vertical circular pipe of 16 mm i.d. In order to know the effects, grid spacers with and without MV were inserted in turn into the test channel. Furthermore, in order to know the effects of inclination angle of the mixing-vane to main flow, two inclination angles, i.e., 30° (MV30) and 20° (MV20) were tested. Pressure drop of flow through the spacer and liquid droplets deposition rate in the section downstream from the spacer were measured with a pressure transducer and double liquid film extraction method, respectively. Experimental data revealed that deposition mass transfer coefficient and the pressure drop were higher for the spacer with MV than that without MV. Regarding the effects of the inclination angle of MV, the vane of MV30 gave higher deposition mass transfer coefficient than MV20 although it increased the pressure drop.

]]>A.E. Segall

An inverse vibration solution was derived for single DOF systems (undamped and damped) using a method based on the least-squares determination of polynomial coefficients representing the unknown force excitation. Initially, a closed-form and generalized direct-solution to the Vibration Equation was derived using standard polynomials to represent the excitation; while simple polynomials and a single DOF system were chosen to demonstrate the method analytically, more sophisticated functions such as Splines, B-Splines, Basis Functions, and/or Finite-Element analysis can be used with the advocated method. In order to solve the inverse problem, the generalized solutions were then used to enforce measured displacement data and the Levenberg-Marquardt algorithm employed to determine the unknown polynomial coefficients representing the base excitation. Results including random errors added to the data (up to ±5%) indicated that the method could be used to determine a time varying excitation; indeed, good agreement was seen between exact and polynomial solution (undamped), as well as an inversely predicted excitation for both damped and undamped systems subjected to a half-sine force history. Given the results, the method appears well suited for complicated scenarios provided the response can be approximated by a polynomial (or more sophisticated functions) and inverse calculations are restricted to the time interval bounding the measured data. In addition, the least-squares inverse approach should be adaptable to more complicated system and excitations by using general purpose finite-element codes. For the current analysis, the least-squares smoothing inherent in the process appears to have helped minimize the influence of measurement errors.

]]>Abdul Kareem F. Hassan and Sara Mohammed

This work aims to investigate experimentally the parameters affecting on the wear debris and the temperature rise due to friction as well as developing the artificial neural network model (ANN) using MATLAB program for predicting the wear, and temperature of disc and pad. Two types of disc made from aluminum and steel are slipping against pad and carried out under dry conditions at different time, rotational speed, and load to examine the wear. The results show that the wear and temperature are increased with increasing the sliding speed, and load or contact time. In addition, the wear of pad is higher when it's contact with aluminum disc, while the temperature of pad is higher when its contact with steel. The ANN model was successfully shows that there is a high ability to predict the wear and temperature as well as the results of model corresponding with the experimental results.

]]>Abdul Kareem F. Hassan and Azzam D. Hassan

Since it is easy to measure the applied torque, an empirical equation to predict the generated shear stress amplitude from the applied cyclic torque (under a low cyclic fatigue) has been carried out in this investigation. The equation has been expressed for a Brass material with a frequency of 375 rpm. The conducted tests in this investigation was completely reversed based on strain at 250℃ whereas the shear strain amplitude, number of cycles to failure, and the maximum cyclic applied torque have been recorded during the tests. A fabricated rig has been used to conduct the experimental fatigue test at high temperature. The fatigue cyclic coefficients were estimated by applying the best fit equation for the recorded data. Ramberg-Osgood coefficients were found by substituting the fatigue cyclic coefficients in the relations that given by McClaflin and Fatemi. The empirical equation to predict the value of the shear stress amplitude was found for each value of the maximum torque that exposure to the material. The best fit of the shear stress amplitude that results from Ramberg-Osgood equation and with the recorded cyclic torque has been estimated. The effect of the temperature was also taken in the consideration on the fatigue strength which clearly observed that the high temperature lead to reduce the fatigue strength.

]]>Abdul Kareem Flaih Hassan Raad Jamal Jassim and Mustafa Muneam Jafaar

This paper employs rigid-plastic finite element DEFORMTM 3D software to estimate the plastic deformation behavior of an aluminum billet during its axisymmetric extrusion through a conical die. The die and container are assumed to be rigid bodies and the temperature change induced during extrusion is ignored. The important parameters which effect on the extrusion process were assumed to be: the reduction of area (0.75), semi- cone die angles (5, 6, 7, 8, 10, 12, and 14^{o}) coefficient of friction is 0.05 and the extrusion speed is 250 mm/s. Under various extrusion conditions, the present numerical analysis estimates the stresses, the die load and the flow velocity of the billet at the die exit. Genetic algorithm coupled with neural network is employed to find optimum die angle leading to minimum stresses without any constraint. The simulation results confirm the suitability of the current finite element software for modeling the three-dimensional cold extrusion of aluminum rod.

M. Abu-Hilal

A Green's Function method for determining the deflection of statically loaded beams is presented. This method may be applied to single and multi-span, statically determinate and indeterminate beams subjected to single or several loads. Also Green's functions for different beams are given. Finally, several examples are given to illustrate the use of Green's functions.

]]>Keiji Sonoya Kosuke Fukui and Motohisa Suzuki

It is considered to be available in reducing the weight of automobiles that the aluminum alloy is applied to manufacture them. The spot welding of aluminum alloys is difficult because of high welding current and small electrical resistance. It is necessary to clarify the relation between the nugget formation and the welding conditions. In this study, the relation between the spot welding conditions and the nugget form was investigated, and the joint strength and the fracture mode were investigated. As a result, the nugget area and micro cracks in the HAZ were increased with increase of the welding current. It is found that in case of aluminum alloys the formation of micro cracks was a main factor of reduction of maximum tensile load of the welded zone.

]]>Tomoji Osada Keiji Sonoya Takeyuki Abe and Masanobu Nakamura

Consumption of aluminum alloys is increasing in order to improve the environmental performance. The aim of this research is to develop a technique to bond aluminum within an atmosphere in a short amount of time and with minimal deformations. In order to accomplish this, the bonding was carried out via use of a metal insert and ultrasonic vibration. Bonding employing the insert metal resulted in a weakened bond due to the generation of an oxide layer on the bonding surface which impeded a bond forming between the metals. The addition of ultrasonic vibration resulted in a stronger overall bond than that created without ultrasonic vibration. This is due to the vibration breaking up the oxide surface, inducing plastic flow at the bond interface.

]]>Abdul Kareem F. Hassan and Osama A. Abdullah

The development of composite materials is characterized by the improvement of their mechanical properties (stiffness and strength) which have widened their application for structural fields like automobile, aerospace, and naval industries. The mechanical properties of composite materials can be upgraded during the manufacturing process by applying an appropriate load on the fibers and curing the corresponding matrix at certain temperature. For that purpose a machine was designed and built to exert load and heat on a composite of carbon fiber mat or glass fiber mat and matrix. The result is a rig agreed with horizontal tensiometer that can be called a prestress machine. This machine holds a certain tension on the fibers while the matrix is being cured. The main parts of the prestress machine are the mold, pulling crosshead, oven and sensors. This paper presents the steps of constructing and using this machine. Experimental investigations were carried out to determine the complete set of stiffness characteristics E_{ij}, G_{ij}, v_{ij} and strength characteristics σ_{i,n}, ε_{i,n}. The outcome results show that this machine can produce prestressed composite materials with much better mechanical properties comparing to those properties of the non-prestressed composite materials.

Halil Atalay and M. Turhan Coban

When simulating refrigeration systems or equipment, knowledge of refrigerant thermodynamic properties is required. While some of the refrigerants are made of pure fluids, some of these refrigerants are made by mixing of two or more pure refrigerants with the predetermined percentages. Properties of refrigerants are a major part of international trade, therefore, it is a subject of interest of international standards. In this study a computer model was developed based on Helmholtz equation of state and cubic spline curve fitting models developed by using saturation thermophysical properties of the refrigerants and refrigerant mixtures. Java programming language was used to model equation of state. As an example the equations for R1234yf and R410A were presented in this paper. With the new model, thermodynamic properties of R1234yf and R410A were compared with REFPROP 9.0. It shows that the total mean deviations of the new model are less than 0.5%.

]]>Masu Yamada Keiji Sonoya and Yuki Watanabe

The effect of cutting conditions such as numbers of tool teeth, depth of cut and cutting speed on the cutting resistance about 12%Cr steel hasn't been studied before. So the effect of cutting conditions on the cutting resistance will be investigated in this paper. The relationship between cutting resistance and work damaged layer will be taken into consideration. The results are as follows. (1)The cutting resistance becomes larger with the increase of the depth of cut and the numbers of tool teeth. It has no relation with cutting speed. (2)The depth of work damaged layer increase with the increase of the depth of cut and numbers of tool teeth. It does not change with the increase of cutting speed. (3)The deformation of cutting surface becomes larger with the increasing depth and numbers of tool teeth. It changes a little with the increase of cutting speed. (4)It was found that the depth of work damaged layer increased with the increase of the cutting resistance. The depth of work damaged layer is thought to have an intimate relation with the cutting resistance. (5)The experimental value for work damaged layer by hardness measuring is thought to be reasonable value, because the experimental value is nearly equal to the evaluated one obtained from Sokolovskii's stress equation.

]]>Xiaoyou Zhang and Satoshi Tanaka

Electrical discharge machining (EDM) has several advantages, such as the capability of machining all conductive materials regardless of their hardness and the ability to deal with complex shapes. In EDM, the machining speed largely depends on the probability and efficiency of the electrical discharges. To obtain a stable electrical discharge, it is necessary to maintain a suitable gap between the electrode and the workpiece. In this study, a three-degree-of-freedom (3-DOF) controlled, wide-bandwidth, high-precision, long-stroke magnetic drive actuator was developed to allow the rapid positioning of the electrode, and EDM experiments were conducted using the developed actuator to confirm the increase in the machining speed. Furthermore, planetary machining experiments were also performed to determine if the developed actuator can be used to adjust the diameter of the machined holes. The experimental results demonstrate that the actuator can rapidly adjust the gap between the electrode and the workpiece. In the experiments, using the actuator increased the machining speed by 89% in comparison with using only the conventional electrical discharge machine. In addition, the diameter of the machined hole can be adjusted by using the multi-DOF positioning function of the actuator.

]]>Fa-Ta Tsai Wan-Yi Lu Rwei-Ching Chang and Ching-Kong Chao

In the case, the system proposed a simple solar powered weather information gathering module, which can be mounted on mobile vehicles, using green energy, Global Positioning System (GPS) and information and communications technology (ICT). When parking in the outdoor, the system operate and the sensor switch too. All the measurement data, not only can provide the real-time local temperature and humidity information to the stranger, who will go to here, because it will detect than the automatic observation station more accurate and more instant. According to the GPS data, it will be uploaded to public homepage, or the cloud database computing parameters, all as an effort to make contribution in the search of new energy resources. Overall the weather information gathering mode uses Android App software, integrated with the image capture function of smart phone and GPS function. Through this system the spindle in the "real-time video transmission system" and "Journey Log" combine to provide more information to integrally analyze and instantly display the weather information of various regions.

]]>Hyung Suk Kang

This paper presents a two-dimensional analysis of reversed trapezoidal fins with variable fin base thickness. Heat loss from the reversed trapezoidal fin is presented as a function of the fin shape factor, fin base thickness, and fin base height. The relationship between the fin tip length and the convection characteristic number, as well as that between the fin tip length and the fin base height for equal amounts of heat loss are analyzed. In addition, the relationship between the fin base thickness and the fin shape factor for equal amounts of heat loss is presented. One of the results shows that the heat loss decreases linearly with the increase in the fin shape factor.

]]>Steven Wang Roy Nates Timotius Pasang and Maziar Ramezani

Due to lack of comprehensive experimental studies on welding processes, and to better understand the mechanisms behind these processes, especially the weld pool shape variations suspected due to Marangoni Effect or surface tension shear stress, a two-dimensional simulation model was developed to study the physics of gas tungsten arc welding (GTAW). Experimental spot-welds on Ti-5Al-5Mo-5V-3Cr was carried out to compare to the model for crucial clues such as, the magnitude of Marangoni convectional stress that is difficult to determine experimentally; and to estimate the Enhancement Factor, an artificial parameter incorporated into the model proven to account for any discrepancies between simulated results and experimental weld pool shapes, due to lack of viscosity temperature dependent data as well as flow instabilities. The model confirmed that Marangoni Convection is indeed the most dominant force in shaping the weld pool, followed by thermal buoyancy force and electromagnetic force. As the investigation went on, the validity of past welding simulations assuming a constant flow scheme was examined, concluding with the recommendation of applying a laminar flow regime at the initial welding times and turbulent flow with elapsing welding time to effectively eliminate simulation inaccuracies.

]]>Gurpreet Singh Khushdeep Goyal and Deepak Kumar Goyal

The composite materials have received great attention due to their light weight, high performance, environment friendly and wear resistance properties and excellent tribololgical properties over the metals and their alloys. There is a good scope to develop new aluminum based composite material which will further improve these properties. Therefore in this research work, a new aluminum based composite material was successfully fabricated by reinforcing with fly ash and Silicon carbide and its mechanical properties like wear resistance, hardness and tensile strength were investigated.

]]>Labbe Fernando

The temperature field and the residual stress were obtained using the finite element method (FEM), for a plane plate with a single-pass welding. The length and width of the plates were 250 and 300 [mm] respectively, and three different thicknesses of 6.25, 12.7 and 25.4 [mm] (¼ [in], ½[in] and 1[in]) were considered. The model used was a two dimensional simplification of the three-dimensional actual problem, and the temperature field was calculated using an uncoupled scheme, this means, the temperature was calculated first and then the stress. The effects of different velocities of the arc between 6 and 8 [mm/s], initial temperature (preheat) between 20 and 200 [°C] (72 and 392 [°F]), and thicknesses of the plate were studied regarding mainly about the final distribution and maximum values for the residual stress.

]]>Albert Wen-Long Yao and Chia-Hui Chiu

Nowadays, the shortage of fossil fuels consuming on vehicles are in an emergent situation. Moreover, the CO_{2} emissions from transportations make a very negative impact on our environment. Therefore, to develop a renewable energy system for transportations becomes an important issue and draw a lot of attentions from academia and government agency. The aim of this study is to develop a wind power system for vehicles. A novel win turbine blade was designed and developed based on the methods of literature survey, TRIZ theory, and the theory of aerodynamics. Then, the system integration with gear, generator, and charge controller were carried out on a moving vehicle which could convert the wind power into electrical energy for use and storage. This study uses the CFD simulation software of ANSYS CFX to analyze the wind flow field of a truck, and simulate the dynamic status of the wind turbine in different locations. The result shows that the proposed wind power system on vehicles could generate about 300Watts while the vehicles are moving. The simulation result also provides very good evidence that the most appropriate installation position is in the front roof of a truck, where it could generate better efficiency of electricity in this research.

Mitesh Mankani and S S Sharma

Beryllium-Copper (BerylCo) alloys serve as a suitable material for fabrication of satellite antennas due to their high 'strength to weight' ratio and favourable electrical properties. Conventionally, satellites use BerylCo strips that are at least 10mm wide. During the designing of nanosatellites certain dimensional constraints prevail that restrict the width of the BerylCo strip to 2mm. This poses various problems as a thinner Berylco strip, when coiled, loses its ability to retain the original shape upon uncoiling. Thus, the yield strength of the Beryllium-Copper strip must be increased by Heat Treatment. The method of Heat Treatment that is to be employed for the same is Solution Annealing followed by Ageing or Precipitation. However, while carrying out this Heat Treatment process, a problem is faced during the quenching phase because the thin strip experiences rapid heat dissipation into the air. In this paper, an attempt is made to adopt the conventional Heat Treatment method with suitable modifications to overcome the limitations.

]]>Maninder Singh Khushdeep Goyal and Deepak Kumar Goyal

Aluminum alloys are used in automobile and aerospace industries because of their low density and good mechanical properties, better wear resistance as compared to conventional metals and their alloys. In these industries there is continues demand to develop light weight, inexpensive and strong material which has led to the development of aluminum alloy metal matrix composites with ceramics as reinforcement particles. In this present work, aluminum based metal matrix composites have been fabricated using SiO_{2} and TiO_{2} as reinforcement materials by stir casting process and wear behaviour, hardness and breaking load have been evaluated.

Dongdong Gao and Zhongxian Yuan

The internal temperature change of an adsorbent bed, which is subjected to the solar insolation, has been numerically simulated. As the intensity of the solar radiation changes with the sun movement, the temperature distribution in the bed evolves continually. Based on the configuration of the evacuated tube bed, a two-dimensional model of heat transfer has been established and numerically solved. To identify the effect of the internal cooling mode, three kinds of thermal boundary condition have been applied to the cooling tunnel. The numerical results reveal that the uniform wall temperature condition presents the best cooling effect, while the natural air convection presents the worst effect. In addition, the temperature change of the bed with the bed diameter has been examined, incorporating with the effect of cooling channel size. For the cooling condition of the natural air convection, the sun-facing side of the bed not only warms up the most rapidly, but also shows the highest temperature. In contrast, the temperature rising of the sun-shading side is much less. The temperature difference between the sun-facing side and the sun-shading side can reach 70℃. The non-uniform distribution of the temperature of the bed will hinder the adsorption cooling performance.

]]>Nader A. Nader Mohammad Ghoneim and Rami S. Alsayed

The purpose of this project is to design and build a solar race car for the world solar challenge. Three main goals were targeted for the competition: lightweight, aerodynamics, and efficiency. The renewable energy is becoming an alternative source for the fossil fuel. Solar energy in particular is abundant all year round within the Kingdome of Saudi Arabia. It is vital for the whole community to utilize this free energy into many areas such as power generation and building of solar cars. As many studies pointed out that the consumption of oil within the Kingdome is an alarming four million barrel per day. Most of it goes to generate electricity and gasoline for the cars. The car speed initially was tested at 70 km/hr and is expected to double for the world solar challenge race. The traveling distance covered will be about 3000 km. The body and chassis of the car were manufactured from fiber glass and aerospace aluminum material. Moreover, a system AC motors were designed, manufactured and assembled accompanied by gearbox, steering, axle, bearings, suspension system. Semi flexible solar panels were installed with power trackers and instrumentation. One driver was accommodated with a car net weight of 300 Kg.

]]>Rayyan Azam Khan Liaquat Ali Khan and Syed Zahid Hussain

Shortage of electricity is one of the main problem in the development of rural areas in Pakistan. Photovoltaic techniques are generally attaining an escalating attention and they're to become very competitive alternative, additionally, environmental issues such as population and global warming impact are attracting experts towards green electricity sources such as solar systems. A standout amongst the most imperative provisions of photovoltaic frameworks is for water pumping, especially in rural areas that have a considerable amount of solar radiation and have no access to national grids. They are generally utilized within household and animals water supplies and small-scale irrigation systems [1]. Water pumping from a PV array is a valid option to pollution-generating diesel and human-powered water pumps. PV-array water pumping can be fulfilled with or without a backup module. With a backup module, energy generated by the sun can be stored in the backup; hence, the application of the water pump can be fulfilled, even to a cloudy day, or at night to operate small loads. The application of photovoltaic is increasing in rural areas due to shortage, unavailability and costly electricity. Solar powered water pumps are commonly used in agriculture and residential level. This designed model deals with solar powered submersible pump. Among many available schemes, it consists of a PV panel, a storing backup, a variable-frequency inverter, a charge controller and induction motor coupled with a water pump. The inverter drives the induction motor, which drives the water pump. To obtain maximumoutput power of the Solar panel, the inverter is operated at variable frequency or soft start to minimize stall current of induction motor [5]. This designed model powers 0.75hp water pump. Different types of controllers can be used to increase frequency gradually from 0 to 50 Hz with 5 sec of delay each, thus voltage is controlled from 0 to 220V AC.

]]>Ketan Diwan and M. S. Soni

Heat transfer enhancement technology provides many advantages in heat exchanger applications. In the present paper, the heat transfer characteristics and the pressure drops of the absorber tube of Parabolic Trough Concentrators with wire-coils inserts are investigated. Water is used as a heat transfer fluid and simulations are carried out in COMSOL Multiphysics® 4.4, for various flow rates of water as well as for different pitch values of wire-coils insert. It is observed that introduction of wire coils increases the turbulence inside the tube, thereby increasing the Reynolds number and hence the Nusselt number. Value of Nusselt number is observed to be increased by 104% to 330% which indicates the increase in the value of convective heat transfer coefficient and hence the heat transfer rates.

]]>Mohammed H. Alhamdo Maathe A. Theeb and Jaafar J. Abdulhameed

In areas with very hot weather conditions (50 to 60℃), the temperature and pressure of the air-conditioning condenser are increased considerably. This causes a decrease in the cooling capacity of the cycle and also causes an increase in the power consumption due to increased pressure ratio. In this work, an experimental and theoretical investigation has been done to improve the evaporator outlet fluid temperature through enhancing condenser performance. For this purpose, several modifications on the refrigeration system have been developed and tested to solve this hot weather problem. The air-side modifications include adding Spray Water above condenser (SW), wet Pad before condenser (Pad), and water Vapor Nozzle in the condenser air flow (VN). The refrigerant-side modification includes adding a pair of Heat Exchangers (HE) for exchanging heat between condenser exit and evaporator exit by using water-antifreeze mixture as a working fluid. A Water-Refrigerant(W-R) evaporator has been designed, manufactured, and compared with original Air-Refrigerant(A-R) evaporator performance. All air and refrigerant-side modifications have been investigated using both types of evaporators. The results indicate that the (SW) modification for enhancing condenser performance is the best method for COP improvement. The COP of (SW) system is found to increase at rate of (44.5 %) and (102.1%) as compared to system without modifications for (A-R) and (W-R) evaporators respectively. The outlet cooling temperature from evaporator has been found to reduce by about (30.3%) for (A-R) evaporator and (23.6%) for (W-R) evaporator. However, (HE+Pad) modification has been found as the best method for improving air side Nusselt number of condenser with an increase of about (4.7) times that of system without modifications. Ten new Nusselt number correlations have been predicted for each type of modifications under investigation by using both Engineering Equation Solver (EES) software and the experimental data. Cost-Benefit analysis in terms of life cycle cost, net present value, cost-benefit ratio, and payback period have been conducted. From the analysis, it can be concluded that using (SW) system will save a significant amount of energy with a payback period of less than five years.

]]>Ameen Ahmed Nassar

In this paper, a successful approach for the vibration analysis of quarter car suspension system using random and step function road profiles, by developing a new graphical user interface (GUI), has been introduced. The main objective of the paper is to show the usefulness and power of Malab GUI in modeling and analyzing dynamic behavior of quarter car suspension system. The second purpose of this paper is to carry out an analysis of using the developed GUI to simulate this system. Illustrated problems in the field of analysis of suspension responses for the quarter car models are carried out. The results show that the developed GUI is very useful for engineers, designers, and analysts of car suspension systems.

]]>Abdul Kareem F. Hassan and Alyaa S. Hashim

This work aims to analytically and numerically study the parameters affecting on the wire drawing process using a 3D finite element model and the effect of these parameters on drawing force. Three-dimensional finite element model using DEFORM-3D V6.1 was built to simulate this process. AL-1100 wire was drawn through a conical die with semi-die angle )α = 6° , 8° , 8.5° , 9° , 9.5° , 10°,, 15° ), reduction ratio ( r = 0.1 , 0.15 , 0.2 , 0.25 , 0.3), friction coefficient ( µ = 0.1 , 0.08 , 0.075 , 0.07 , 0.065 , 0.06 , 0.05(, bearing length ( BL= 0.5 , 0.75 , 1 , 1.25 , 1.6 ) mm, drawing velocity ( 5000, 7500, 10000, 12500, 15000, 17500, 20000)mm/sec. were taken in this study. Many simulations with different parameters were taken to capture the optimum die angle. The results show that the optimum die angle depends on reduction in area (α= 9.5°, 9.5°, 9.5°,10°, 10°) for reduction in area (r= 0.1, 0.15, 0.2, 0.25, 0.3). The drawing force estimated from finite element results was compared with that of analytical results and found in line with maximum error percentage of 4%. The results of finite element model were analyzed statistically using SPSS software in order to find the relationship between the above factors and drawing force.

]]>Masaru Sumida

360-degree bend flowmeters were applied to determine pulsatile flow rates in water. Experiments were performed using bend flowmeters with curvature radius ratios of 7, 10 and 30 under the conditions of Womersley numbers of α=2.1−18, mean Reynolds numbers of Re_{ta}=800−5×10^{4} and oscillatory Reynolds numbers of Re_{os}=600−1.6×10^{4}. The pressure difference across the bend was found to be independent of the pulsation frequency and to conveniently vary with almost the same phase as the instantaneous flow rate. A method for measuring the instantaneous flow rate is proposed as well as a method for estimating the time-mean and amplitude values of the pulsatile flow rate. It is concluded that 360-degree bend flowmeters can be used to measure the pulsatile flow rate.

Jagdev S. Pawar M. Chouksey and K. Tripathi

Computer aided models are used to present physical systems. These models further find their use in various type of analysis including static and dynamic analysis. In this work computer aided modeling of components of bolted joint and their finite element analysis has been carried out through ANSYS workbench software under definite loading conditions, to obtain different stress and displacement values. The models of the plates, bolt, nut have been made in a CAD software. The model thus made has been imported in the Ansys Workbench for the analysis using the IGES file format. The analysis includes detailed stress analysis of a single lap bolted joint. The spatial variation of total deformation, directional deformation, equivalent stresses and principal stresses is shown. The effect of preload has also been investigated on all these quantities. It has been shown that with increasing pretension the deformation and stresses increase.

]]>Dhananjay R Dolas and Sudhir Deshmukh

Diesel engine is use in various field for the different application, the performance of engine is depends on the engine systems & components. The cooling system is one of the important systems for diesel engine, the major breakdowns are occurring due failure cooling system & its components. This paper is presented the reliability analysis of cooling system of diesel engine using for compressor application, this work is using a time to failure data of cooling system and two parameter Weibull distribution analytical least square method & Minitab 16.1R Software are used for parameter estimation, The results are shows reliability, Availability, Mean time between failure, Failure rate and Failure density. This is helpful for designing & manufacturing of components and modification.

]]>Gulovleen Singh Roshan Lal Virdi and Khushdeep Goyal

The slurry Erosion behaviour of AISI 316L stainless steel has been investigated in this research work. The samples hard faced with cobalt based (stellite-6) and titanium based alloys specimens were used during the experimentation. Erosion test was performed on a Slurry Erosion test rig fabricated as per ASTM standards G73. Three variables which were used in the experimentation are concentration level of the Slurry, nozzle diameter of the jet and average particle size of erodent. After a fix time, weight loss of samples was compared. It was found that the samples hard faced with titanium based alloy are more hard than hard faced with cobalt based alloy and substrate material.

]]>Maamar Ali Saud AL-Tobi and Khalid F. Al-Raheem

The wavelet de-noising technique with wavelet based function has been used in this paper for bearing fault detection. The applications of the wavelet de-noising show that the fault pulses in time-domain of the de-noised signals are easily to be detected as a result of removing the covering noise, which is not possible through the time-domain analysis of the original signal. Furthermore, the reciprocal period which matches the bearing fault frequency can be easily detected without further analysis by FFT-Spectrum.

]]>Abdul AlKareem F. Hassan Safa A. Saleh and Zainab H. Jibar

In this work, the influence of varied deformation percentages on the hardness and grain size, effective strain variation during simple upsetting is studied. Also, hardness variation in a typical cold upset forging process is predicted by relating hardness and effective strain evolution in a simple upsetting operation empirically. Five different deformation percentages, (13%, 17%, 32.4%, 41%, 50%), are considered for experimentation. Ring compression tests were conducted to determine the friction factor 'm'. The upset-forging tests were conducted at room temperate and for different deformation percentage on the pure copper cylindrical specimens of 30 mm diameter with aspect ratio (h_{o}/d_{o}) of 1.0. The distribution of hardness in the cold upset specimen was measured using the Brinell Hardness Tester. Also, this work discussing metallographic study of the upset specimens. The micrograph of samples is processed with the 'Adobe Photoshop CS2' program and then applying the "Image J" program for estimating the average grain size. The upsetting operation was simulated using a commercial finite element code, ANSYS ver11.0. The results show that the finite element procedure is effective procedure to simulating cold upsetting process with maximum error (7.7%).

Begüm Y. Dağlı and B. Gültekin Sınır

The transverse of free vibration of pipes conveying fluid has been examined by using Euler-Bernoulli beam theory to show the effect of varied boundary conditions on pipes dynamic behaviors. The equation of motion of the pipe conveying fluid is obtained with a new approach with the assumptions of ideal fluid, which moves in the vertical direction with pipe and the pipe makes small oscillations, by Hamilton’s variation principle. The flow in the pipe was modeled by considering well-known Euler equation. The dimensionless equations are solved for two different set of non-classical boundary conditions. The natural frequency equations and the critical flow velocity equations are obtained and the relation between the mass ratio and vibration frequency is examined by solving the differential equations. The values of natural frequencies caused by the fluid velocity are presented graphically.

]]>Yen-Tso Chang Han-Ching Lin Chi-Jui Huang Chun-Hsien Chen Chien-Jen Lin and Go-Long Tsai

Applying software Ansys-Fluent to analysis the effect of piezoelectric fan device installed inside rectangular channel by numerical simulation method. The piezoelectric fan is activated by reversible piezoelectric effect in piezoelectric material, change rectangular channel flow field construction, then it affects heat flow status in advance. Numerical simulation parameter are included Nusselt number (N_{u}), distance between peak of fan blades to front part of heat sink (L_{g} =0, 5, 10, -11.25, -22.5, -33.75, -45), height from center on piezoelectric fan bottom side (H_{w} =10, 16, 21), number of piezoelectric fan (single-fan and twin-fan), phase-shift (in-phase and counter-phase), and numbers (n=10, 14) for heat sink fin. This result is indicated that good position to temperature dropped greatly is located from the front part of piezoelectric fan to the front of heat sink (L_{g} = -22.5) under fixes distance (H_{w} = 21) from piezoelectric fan to channel also found to provide double piezoelectric fan heat drop effect is equal to single one, however, double piezoelectric fans would provide higher heat dissipation as Counter-phase. The performance of piezoelectric fan is improved depends on change height (H_{w}) from center of piezoelectric fan to channel bottom; the height (H_{w}) shall be decreased as piezoelectric fan placement at the front of heat sink.

Pravat Ranjan Pati and Alok Satapathy

Linz-Donawitz (LD) slag a major solid waste generated in huge quantities during steel making. It comes from slag formers such as burned lime/dolomite and from oxidizing of silica, iron etc. while refining the iron into steel in the LD furnace. Although a number of ways for its utilization have been suggested, its potential as a filler material in polymeric matrices has not yet been explored. The present work reports the possible use of this waste in glass fiber reinforced epoxy composites as a filler material. Hybrid composites consisting of bi-directional E-glass-fiber reinforced epoxy filled with different LD slag content (0, 7.5, 15, 22.5 wt%) are prepared by simple hand lay-up technique. The composites are characterized in regard to their density, porosity, micro-hardness and strength properties. X-ray diffractography is carried out in order to ascertain the various phases present in LDS. This work shows that LD slag, in spite of being a waste, possesses fairly good filler characteristics as it modifies the strength properties and improves the composite micro-hardness of the polymeric resin.

]]>Alok Agrawal and Alok Satapathy

In this paper, an attempt to determine the effective thermal conductivity (k_{eff}) of particulate filled polymer composites using finite element method (FEM) a powerful computational technique is made. A commercially available finite element package ANSYS is used for this numerical analysis. Three-dimensional spheres-in-cube lattice array models are constructed to simulate the microstructures of particulate filled polymer composites with filler content ranging from 2.35 to 26.8 vol %. Composites with similar filler contents are then fabricated using compression molding technique by reinforcing micro-sized aluminium oxide (Al_{2}O_{3}) in polypropylene (PP) resin. Thermal conductivities of these composite samples are measured according to the ASTM standard E-1530 by using the Unitherm^{™} Model 2022 tester. The experimentally measured conductivity values are compared with the numerical values and also with those obtained from existing empirical models. This comparison reveals that the FEM simulated values are found to be in reasonable good agreement with the experimental data. Values obtained from the theoretical model are also found to be in alignment with the measured values within percolation limit. Furthermore, this study shows that there is gradual enhancement in the conductivity of PP resin with increase in filler percentage. It is noticed that with addition of 26.8 vol % of filler, the k_{eff} of composite increases to around 6.3 times that of neat PP. This study validates the proposed model for PP- Al_{2}O_{3} composite system and proves that finite element analysis can be an excellent methodology for such investigations.

Amal Nassar and Eman Nassar

The effect of addition of fine size from SiC material (SiC) with different weight percentage on the mechanical; thermal and physical properties of chopped carbon fiber reinforced epoxy composite has been studied. Mechanical and physical properties are studied by the change in the SiC material content to study the behavior of the composite material when it is subjected to load. The thermo mechanical properties are studied by using dynamic mechanical analyzer. The results for mechanical and physical properties of fine SiC material (SiC) filled carbon fiber reinforced epoxy composite are improved than unfilled carbon fiber reinforced epoxy composite. Analysis of viscoelastic for the different SiC content indicate adding 25 wt. % from SiC reducing the capacity of the energy absorption of the composite material and increasing the elastic behavior of the composite.

]]>Pham Son Minh and Phan The Nhan

In injection molding process, improving the part quality by reducing the warpage is an issue, especially with the thin-walled product. In this paper, the injection molding process was applied to a rectangular plate of 150 mm x 30 mm. The part thickness was varied from 1.0 mm to 2.5 mm. Three types of material as polypropylene (PP), acrylonitrin butadiene styrene (ABS), and polyvinyl chloride (PVC) were selected for observing the influence of volume shrinkage ratio on the warpage. Then, different weight ratios of CaCO_{3} (10%, 20%, 30%, and 40%) additive were mixed with the PP material and then, the mixture was molded. The result shows that the volume shrinkage ratio of plastic material has a strong influence on the part warpage with the thickness of 1.0 mm, 1.5 mm, and 2.0 mm. However, with the thickness of 2.5 mm, the different warpage under three types of plastic is not strongly. With the CaCO_{3}, the result shows that the more the CaCO_{3} additive, the lesser is the part warped. However, with a thickness of 2.5 mm, the CaCO_{3} has a negative influence on the warpage. In addition, this research was achieved by both simulation and experiment. The comparison shows that the simulation result and experiment result agree well.

Ameen Ahmed Nassar

In this paper, a new approach for the mixed mode fracture mechanics analysis of plates using crack extension technique, by developing a new graphical user interface (GUI), has been introduced. The main objective of the paper is to show the usefulness and power of Matlab GUI in investigating and analyzing the effects of crack configurations and orientations on the calculation of stress intensity factors for cracked plates. The second purpose of this paper is to carry out an analysis using the developed GUI to simulate different crack configurations such as central-crack plate, single-edge plate, and double-edge plate. Illustrated problems in the field of analysis of fracture mechanics are carried out. The results show that the developed GUI is very useful for engineers, designers, and analysts of fracture mechanics problems.

]]>Yi-Chang Wu Li-An Chen and Che-Wei Chang

This paper presents an analytical process for predicting the mechanical efficiency of bicycle internal drive hubs composed of planetary gear mechanisms. An existing 14-speed internal drive hub is introduced and is taken as an example to demonstrate the analytical process. Kinematic analysis, static torque analysis, power flow analysis and mechanical efficiency analysis of this internal drive hub are illustrated by applying the fundamental circuit method.

]]>G. Arcidiacono and A.P. Mirarchi

On a daily basis, the concrete problems with researching solutions deal with the psychological inertia, the tendency to think and follow the same known mental schemes. The current work shows how the TRIZ can develop new and effective project solutions thanks to the examination of different prospective and points of view. In particular, the authors want to retrieve the analysis and the solutions for an anomaly found in an industry that designs and builds moulds and equipment for the production of aluminum food containers.

]]>Chang-Pin Lin and Hung-Lin Dai

Project management methodologies have been the most utilized management tools in today's industry and the Critical Path Method considers the logical dependencies between related activities that may have to share common resources. This method has then been expanded to allow for the identification of resource-constrained activities and the size of those resources. They are usually called activity-based resource assignments and leveling. However, once the number of resources increases, it becomes more and more difficult to draw the corresponding graph/network and explore the resource- constrained critical path. Therefore, in order to solve a multiple-resource-constrained project, the Petri Nets theory is introduced for modeling those resource sharing processes. Because Petri nets is commonly used for modeling the dynamic behavior of discrete systems, it is intended in this research to apply Petri net theory in modeling and analyzing complicated projects with multiple resource constraints. Furthermore, analysis on the size of each resource for performance enhancement can then be done by changing the numbers of tokens in each of the resource places that were added for resource constraints. Cost analysis has to be reconsidered since the additions of resources constraints will alter the original schedule of each activities and increase the duration of the project. Activity crashing may have to be done that shifts more resources towards required activity and results in decreased project duration.

]]>Akash Rathi Abhishek Mahor Rajeev Ranjan Abhishek Gajbhiye A. Rehman and C. M. Krishna

End milling using a solid mill cutter is widely used in aerospace, automotive, biomedical, and chemical industries. However, a comprehensive characterization of chip morphology and micro structural and mechanical behavior of machined chips is lacking in the literature. A series of end milling experiments were conducted for studying the chip morphology of Aluminum metal matrix composite. A new multi-view approach to fully characterize metallurgical aspects of chip& chip morphology including top surface and free surface is taken up in this research paper. Each view of the 3-dimensional (3D) chip has been studied for different characteristics. The variation of chip dimensions with cutting parameters was also determined.

]]>Chan Ho Park Min Ho Kwon Nak-Tak Jeong Seulgi Lee Myung-Won Suh Hyun-Soo Kim and Sung-Ho Hwang

The goal of this paper is to invent a simulation tool for developers of electric vehicle unit system. An electric vehicle simulator structured by MATLAB/SIMULINK can change all kinds of important parameters to use GUI and observe the results. Also, if it has a new MATLAB/SIMULINK model or an experimental data of an invented component, it can be applied to perform a simulation. Additionally, we conducted a simulation in a virtual environment with a model, inventing practical driver conduct, and thus we could obtain a practically reliable simulation data. On this paper, we present each characteristic briefly and finally set Nissan Leaf vehicle as a simulator to show possibilities of a simulator as the simulator obtains similar results compared with a practical vehicle.

]]>Patoda Lalit Aharwal K. R. and Jaiswal Sandeep

The heat transfer from surfaces may in general be enhanced by increasing the heat transfer coefficient between a surface and its surroundings, and by increasing the heat transfer area of the surface, or by both. In most cases the heat transfer is concerned with the application of artificial surface roughness techniques as a turbulence promoter for convective heat transfer enhancement. To measure the transient and local convective heat transfer coefficient of an artificial roughened duct using liquid crystal thermography (LCT) technique, an experimental setup have been designed and developed. The aspect ratio of duct was maintained as three with relative roughness height ratio (e/D) of 0.13 and angle of attack is 900 for the range of Reynolds number from 7000 to 17500.

]]>V. Srinivas Ch. Kodanda Rama Rao M Abyudaya and E Siva Jyothi

This work presents the extreme-pressure behavior of 600 N base oil dispersed with MoS_{2} Nano particles with 1 volume percent of polyisobutylenesuccinamide as dispersant. MoS_{2} Nano particles were dispersed in 0.05, 1.0 wt. % and tested for Extreme pressure behavior on a 4 ball wear tester using the test method ASTM D 2783. The weld load and load wear index of base oil and oil dispersed with Nano particles are evaluated and compared for improvement. Prior to dispersion, the MoS_{2} Nano particles are suitably surface modified to make them uniformly disperse in oils. The seizure load, weld load and load wear index of Nano particles dispersed oils have improved remarkably compared to Base oil. Metallographic studies done on the wear balls show that Nano particles get deposited on the worn area preventing the welding of the surfaces and hence higher weld load. The wear scar of bottom there balls are also found to be less for Nano dispersed oils compared to base oil and hence lower load-wear index.

S. Mahto and U.S. Dixit

In this work, finite element method based on Lagrangian formulation is used for obtaining the equations of motion of the double link flexible revolute-jointed robotic manipulator. Both the links are considered as Euler-Bernoulli beams. A parametric study is carried out for the double link flexible robotic manipulator through linear modeling technique. A comparative study for dynamic response is carried out for the uniform beam manipulators under various types of excitations.

]]>J. Anitha Raja Das and M. K. Pradhan

Modeling and optimization of machining parameters are very important in any machining processes. The current study provides predictive models for the functional relationship between various factors and responses of electrical discharge machined AISI D2 steel component. Surface Roughness (Ra) is important as it influences the quality and performance of the products, hence the minimization of surface roughness in manufacturing sectors is of maximum importance. It is also realistic and desirable if the finished parts do not need further any operations to meet the required optimum level of surface quality. For achieving the required optimum levels of surface quality, the proper selection of machining parameters in EDM is essential. Four significant machining parameters, Ip (Pulse Current), Ton (Pulse on Time), Toff (Off Time) and V (Gap Voltage) in the EDM process have been selected and with the various combination experiments were conducted. A mathematical regression model was developed to predict the average Surface Roughness in electrical discharge machined surface. The developed model was validated with new experimental data. The model was coupled with genetic algorithm to predict the minimum possible surface roughness. It is found that the predicted and experimental values were close to a certain extent, which specifies that the established model can be successfully used to predict the surface roughness. Also, the developed model could be used for the selection of the levels in the EDM process for saving in machining time and product cost can be achieved by utilizing the model.

]]>Ashish Gupta and Amandeep Singh Ahuja

The interest in dynamic behavior of railway bridges has increased in recent years with the introduction of high speed trains. Higher speeds of the trains have resulted in larger and more complicated loads than earlier, producing significant dynamic effects. The dynamic aspects are of special interest and have often shown to be the governing factor in the structural design. Dynamic analysis of railway bridges is, therefore, required for high train speeds. The objective of this paper is to investigate the dynamic behavior of an existing railway bridge subjected to high speed trains. A railway bridge model has been developed to study dynamic effects such as oscillations produced by moving loads of constant magnitude and to obtain a relation between the velocity, acceleration, load position and deflection of the bridge at any instant of loading, with and without damping, with the help of MATLAB software. The simulation results indicate that the speed of the vehicle is a very important parameter influencing the dynamic response of a railway bridge. The amplitude of bridge deflection has been found to be the highest at speeds between 75 and 85 m/s. Further, the introduction of damping has been found to greatly influence of the amplitude of bridge deflection response. However, the peak deflection values appear at the same speed independent of the damping coefficients.

]]>Puneet Kumar Singh and C. Murali Krishna

Traditional robots have rigid underlying structures that limit their ability to interact with their environment. For example, conventional robot manipulators have rigid links and can manipulate objects using only their specialised end effectors. These robots often encounter difficulties operating in unstructured and highly congested environments. A variety of animals and plants exhibit complex movement with soft structures devoid of rigid components. In this paper survey of literature related to continuum arm of robotic manipulator based on biological inspiration is carried out. It defines the fundamental difference between discrete, serpentine and continuum robot devices; presents the ‘state of the art’ of continuum robots and outlines their areas of application; and introduces some control issues. Finally some conclusions regarding the continued development of these devices are made.

]]>R.K. Sharma and P. Ganesan

The solidification process of nanofluid (water + copper nanoparticles) has been studied numerically in this paper. The horizontal walls of the cavity are insulated while inclined walls are kept at constant but different temperatures. The effects of nanoparticle dispersions (ϕ = 0%, 10% and 20%) and the temperature difference between hot and cold wall on the solidification of Cu-water nanofluid inside the cavity is investigated numerically. Enthalpy-porosity technique is used to trace the solid-liquid interface. It is illustrated that the suspended nanoparticles substantially increase the heat transfer rate which is further increased by the temperature difference.

]]>N.D. Darwai S.M. Murigendrappa and K.V. Gangadharan

A comparative study on the effect of magnetic shape memory alloy (MSMA) under electromagnet and biased field has been carried out numerically and experimentally. The influencing parameters, magneto-strain, power efficiency and time response have been considered. The intensity and uniformity of the magnetic field are predicted numerically incorporated in the experimentation. The pre-stressed specimen is subjected to electromagnet field and bias field actuations. The measured data demonstrate an improvement in the performance of initial magneto-strain with an average difference of 75% and 27.2% reduction in time response of the MSMA actuator at lower input power.

]]>Tanmoy Chakraborty and Ravikiran Kadoli

This paper presents the mathematical and numerical modelling of type N thermocouple using the transient diffusion phenomenon and finite difference and finite volume concept. Here particles of 5 inert atmospheres employed for checking the effect of drag force on sheath mass and to recommend one media for numerical model calculation. Environment is hot for which concentration of sheath particle increase near sheath but decrease as distance increase. Von-Neumann stability incorporates for time step calculation in numerical work.

]]>B. R. Moharana and S. K. Sahoo

Laser welding is an advance non-traditional and high energy beam welding technique for dissimilar material, which is being increasingly used in industries like automobile, nuclear reactors, aerospace etc. Again it is a very tough task to joining dissimilar materials due to their properties variation. In this present work two dissimilar metals such as copper and AISI 304 stainless steel are taken into consideration. Laser weldings are performed using a pulsed Nd: YAG laser welding machine. Experiments are carried out by taking three process parameters such as laser power, welding speed and pulse duration with three levels each. A statistical design of experiment (DOE) technique i.e. Response Surface Methodology (RSM) is adopted for analysis of maximizing the tensile strength. The back propagation artificial neural network (ANN) technique is used to predict the strength of the welded area. The predicted data are compared with the experimental results and is found to be in agreement.

]]>P.Venkateswara Rao G.V.Ramana Murty and G. Venkata Rao

This paper examines the effect of twist in diffuser vane from hub to shroud on the performance of an industrial centrifugal compressor stage. The chosen diffuser has an aerofoil section with varying blade chord from hub to shroud due to blade twist or in other words, the solidity of the diffuser blade is varied from hub to shroud. The twisting is given to the diffuser blade by rotating the diffuser blade opposite to the direction of rotation of the impeller keeping its leading edge as origin resulting in different stagger angles from hub to shroud. The analysis was conducted at an impeller tip Mach number of 0.35. The overall stage performance is evaluated in terms of head coefficient, stage efficiency and power coefficient of the stage and static pressure recovery coefficient of diffuser vanes for different diffuser vane twist angles with varying flow coefficients. The observed optimum twist for the best performance is 9^{°} for the chosen impeller diffuser configuration.

D. Sidda Reddy A. Seshu Kumar and M.Sreenivasa Rao

Inconel 800H has got wide applications due to its resistance to high temperature, corrosion. Because of its poor machinability to process it, among nontraditional processes abrasive water jet machining is commonly used. Abrasive Water Jet Machining (AWJM) of Inconel 800H has commercial significance due to its good machining characteristics. In the present paper an attempt has been made to optimise machining parameters employed in Abrasive Jet Machining of Inconel 800H using Taguchi method. The approach used is based on the analysis of variance and signal to noise ratio (SN Ratio) to optimize the AWJM process parameters for effective Material Removal Rate (MRR) and Surface Roughness (SR). Important AWJM machining parameters such as water pressure, focussing tube size, traverse speed & abrasive flow rate were predicted for optimised MRR and SR. It was confirmed that determined optimal combination of AWJM process parameters satisfy the real need for machining of Inconel 800H in actual practice.

]]>Jasem M. Alrajhi and Ahmed Abed

Dynamic vibration absorber (DVA) is used to reduce the system vibrations by converting the main system from one degree of freedom to two degrees of freedom. In this paper the effect of non-linear damper is tested, diesel engine with imbalance rotated mass is used to test the non-linear dynamic vibration absorber (NDVA), the diesel engine response of the DVA behavior for both linear and non-linear dampers is created using mathematical model and MATLAB software.

]]>Mahesh Chudasama and Harit Raval

3-roller conical bending process is one which is used for producing conical sections or cone frustums from metal plates for various industrial applications. The plates to be bent are cut for the required size and shape and then rolled between three cylindrical rollers. The plate is kept between one top roller and two bottom rollers. Than the top roller is lowered down and the plate gets bend. The rollers are rotated to get the roll bending of the plate. Final dimension of the cone frustum are achieved through setting appropriate machine setting parameters. An attempt is made in this paper to develop the analytical model for the prediction of the bending force during the stage of dynamic roll bending. During the roll bending of the plate there will be shear stresses along with the normal stresses. The analytical model has been developed considering these shear stresses. The model consists of various parameters like material parameters and geometrical parameters. Based on the analytical models derived, effects of some of the material parameters on dynamic bending force have been studied. In the development process complex mechanics involved in this process has been simplified so it will give insight of the process and will be helpful to the researchers and designers working in the area of metal forming, especially in roll bending process.

]]>Amandeep Singh Ahuja and Ashish Gupta

A warship may be detected in hostile waters because of its unique acoustic signature. A typical two-stage passive vibration isolation system used on ships and submarines to isolate onboard machinery is the floating raft isolation system. The passive isolation system, though robust, may result in substantially high transmission of forces to the foundation at certain excitation frequencies, adversely affecting the ship’s stealth. This paper highlights the results of a simulation study aimed at the design of a semi-active floating raft vibration isolation system with the objective of mitigating the acoustic signature of a warship by minimising the transmission of forces, resulting from operation of onboard machinery, to the foundation. A semi-active control scheme with variable damping has been proposed for the floating raft, the variable damping being achieved by means of an electrorheological (ER) damper. A fuzzy logic controller has been designed to achieve the best isolation effect by analysing the characteristics of the frequencies in the excitation signal. The designed semi-active control system is subjected to a time-varying signal, each time-segment corresponding to a different optimal damping ratio. The MATLAB simulation results indicate that the proposed fuzzy logic control method is more effective in vibration isolation than the passive method thereby indicating the potential of the designed semi-active control system in reducing a ship’s acoustic signature.

]]>R.Prabhu Sekar and G.Muthuveerappan

The gear smoothness in the transmission of power mainly depends on the contact ratio. When the contact ratio is higher, the load shared by the pair of teeth in mesh will be lower. In the helical gear, the additional contact ratio is created due to face advance which is called face contact ratio and it provides the higher contact ratio than that of spur gear. The face contact ratio can improve by changing the few parameters such as helical lead and face width. In the present work, the face contact ratio is improved by altering those parameters and their effects on the load sharing based fillet stress are also determined for one mesh cycle in the asymmetric helical gear designed through direct design procedure using finite element method.

]]>P. Marimuthu and G. Muthuveerappan

This study explores the influence of some gear parameters such as addendum height, teeth number and module on load sharing aspect and the subsequent stress analysis. The multi pair contact model in finite element technique is used for a reasonable accurate prediction of the stresses with the application of load at high pressure angle side. Also, a unique Ansys parametric design language code is developed for this study. Finally the increase in addendum height results to increase the bending stress for a load at critical loading point. However the increase in teeth number and module leads to decrease in the load sharing based bending and contact stresses.

]]>Karel Vitek

When determining stress states by the hole-drilling method, it is necessary to take into account the experiment performance accuracy. The drilled holes eccentricity appears as a frequent imperfection, which influences essentially the reliability of their stress state assessment. This paper presents the hole-drilling measurement method corresponding to the E 837 standard method, but, at the same time, it is more universal. This method transforms the full stress tensor of the drilled hole position by the regression coefficients and describes the state of strains released in the hole surrounding, based on the hole center distance and its depth. The regress coefficients are not defined in the method concretely for the rosette but they are universal both for the isotropic Hooke’s materials and for the other measuring elements. The method defines the way for the processing of the released strains measured with a defined measuring element and involves naturally the influence of the drilled hole eccentricity and so it is possible, in the hole-drilling method, to apply measuring elements more simply, without determining their specified regression coefficients.

]]>K. Torabi H. Afshari and M. Heidari-Rarani

In this paper, differential quadrature element method (DQEM) is used to analyze the free transverse vibration of a multiple cracked non-uniform Timoshenko blade rotating with a constant angular velocity. The blade’s deflection is assumed to be small so that the nonlinear terms can be neglected. Governing equations, compatibility conditions at the damaged cross-sections and boundary conditions are derived and formulated by the differential quadrature rules. First, the precision of the proposed method is confirmed by the exact solutions available in the literature. Then, the effect of angular velocity value as well as the location, depth and numbers of the cracks are investigated on the natural frequencies of the blade. The advantages of the proposed method are applicable for blades with any arbitrary variable section and less time-consuming for cases with several cracks.

]]>N. Anandan P. Sathiamurugan and P. Mathiazhagan

The effect of various film profiles on the load carrying capacity of adiabatically lubricated fixed pad thrust bearing is analyzed in this work. One dimensional film thickness profiles such as taper, polynomial, catenoidal, exponential and truncated cycloidal are employed here to predict the load carrying capacity of the fixed pad thrust bearings. Results are computed for various levels of speeds (5m/s, 15m/s, 25m/s) at two levels of viscosity (0.5Pas, 0.05Pas). The shape of the film profile do influence the load carrying capacity of the thrust bearings and the polynomial film thickness profile has the maximum influence when compared to other film profiles.

]]>Puran Singh

Tunnel boring machines (TBM) excavate tunnels with a circular cross section through a variety of rock strata. They can be used to bore through hard rock or sand and almost anything in between. Tunnel diameters can range from a metre (done with micro-TBMs) to 19 metres. Tunnel boring machines are used as an alternative to drilling and blasting (D&B) methods. A TBM has the advantages of not disturbing surrounding soil and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel, and makes them suitable to use in built-up areas. The key disadvantage is cost. TBMs are expensive to construct, difficult to transport and require significant infrastructure. A tunnel boring machine (TBM) typically consists of one or two shields (large metal cylinders) and trailing support mechanisms. At the front end of the shield a rotating cutting wheel is located. The cutting wheel will typically rotate at 1 to 10 rpm (depending on size and stratum), cutting the rock face into chips or excavating soil (muck). A TBM can cut through rock at up to one kilometre a month. Powerful hydraulic rams force the machine’s cutting head forwards as the rock is cut away called the feed. The action here is very much like an earthworm. The rear section of the TBM is braced against the tunnel walls and used to push the TBM head forward. At maximum extension the TBM head is then braced against the tunnel walls and the TBM rear is dragged forward. As tunnels has become one of the most important source of underground transportation like metro rail and other projects, this TBM can be utilized as an easy and effective machine for more better results. Because of their demonstrated capabilities in attaining high rates of advance in civil tunnel construction, the hard rock mining industry has always shown a major interest in the use of TBMs for mine developments. The successful application of TBM technology to mining depends on the selection of most suitable equipment and cutting tools for the rock and ground conditions to be encountered.

]]>Ashok Dargar

In order to select the best possible chain or mechanism at the conceptual stage of design, the designer should be able to read the characteristics of the kinematic chains based on their topology. To accomplish this it is only necessary to associate logically certain characteristics of a chain to perform a task, with the structure and then generalize. Based on this belief in the present work chains are modeled as a system of springs connected in series to reveal some of the characteristics like stiffness and compactness. The concepts developed are applied to platform type robots, which are gaining in importance.

]]>K Rezapour B A Mason A S Wood and M K Ebrahimi

The natural gas as an alternative fuel has economical and environmental benefits. Bi-fuel engines powered by gasoline and compressed natural gas (CNG) are an intermediate and alternative step to dedicated CNG engines. The conversion to bi-fuel CNG engine could be a short-term solution to air pollution problem in many developing countries. In this paper a mathematical model of a bi-fuel four-stroke spark ignition (SI) engine is presented for comparative studies and analysis. It is based on the two-zone combustion model, and it has the ability to simulate turbulent combustion. The model is capable of predicting the cylinder temperature and pressure, heat transfer, brake work , brake thermal and volumetric efficiency, brake torque, brake specific fuel consumption (BSFC), brake mean effective pressure (BMEP), concentration of CO_{2}, brake specific CO (BSCO) and brake specific NOx (BSNOx). The effect of engine speed, equivalence ratio and performance parameters using gasoline and CNG fuels are analysed. The model has been validated by experimental data using the results obtained from a bi-fuel engine. The results show the capability of the model in terms of engine performance optimization and minimization of the emissions. The engine used in this study is a typical example of a modified bi-fuel engine conversion, which could benefit the researchers in the field.

Andrej Cupar Vojko Pogačar and Zoran Stjepanović

We present analysis methodology for different types of geometry. This is needed for classification methodology of surfaces. We have proposed several classes and ways to place surfaces in proper classes, according to their characteristic curves. Several state-of-the-art cases were analysed with Grasshopper (GH) procedure. Classes are explained and some shapes are tested. Classification is necessary for further design improvement and analysis of existing geometry.

]]>Lukas Bridik and Olga Cicakova

This article is treating the increase of hardness of different types of steals used for firearm manufacturing, using nitriding of steel in nitriding oven. The article evaluates hardening processes from the surface to the core of different nitrided steels of a material considering its use in arm manufacturing.

]]>Georgios Andreadis K.-D. Bouzakis P. Klazoglou and K.Niwtaki

The manufacturing sector is considered an important field to the industry. Its products help manufacturers to achieve more control with less labor and more output with less cost. Current technology and especially Artificial Intelligence effectively increase productivity and reduce the cost of operations, which is the key to commercial success. The main representatives of information technology in the industrial applications are the agents. They provide an efficient way to design and implement engineering environments and the agents’ technology is recognized as a new approach for the CAD/CAPP/CAM systems. This paper provides a view of the current agent technology in forenamed systems and constitutes an attempt to a) categorize multi-agent systems according to the coordination mode among the agents and b) classify the agents that take action on them, depending on their functions.

]]>Hana Pechová Václav Koutný and Jiří Faltus

The Brasses are copper alloys. The main element is zinc brass. The most widespread are Cu and Zn binary alloys with different contents of zinc. Binary brass make up a relatively large group of copper alloys in which zinc content varies from 2.5 to approximately 49 %. In addition, there brass, which, besides zinc has other elements. These alloying elements give the brass its material properties. According to the zinc content is divided into low, medium and high percentage of zinc brass.

]]>Gennadiy Lvov and Olga Kostromitskaya

Continuum damage mechanics approach has been used for analysis of the autofrettage process. General set of government equations of elastic-plastic bodies is derived by using the effective stress concept. Strain – damage coupling constitutive equations are developed on the base of plasticity relationships with bilinear kinematic hardening and kinetic law of ductile damage evolution. Damage of the material leads to decrease of Young’s modulus after plastic deforming that affects on the unloading stage of autofrettage. Influence of material damage on residual hoop stress was considered by the example of autofrettaged thick-walled cylinder. Numerical results were obtained by finite-element method for plane-strain case. These results showed that material damage modifies the residual stress distributions and reduced residual hoop stress value on bore area.

]]>Christopher Provatidis

This paper proposes a propulsion cycle to enable an object to perform slow unidirectional sliding on the horizontal ground when an inertial drive, made of contra-rotating eccentric masses, is attached to it. Two masses are driven by one or two synchronized motors, which rotate at a variable angular velocity according to a predefined function with a period of 360 degrees. The aforementioned predefined law of rotation constitutes the proposed propulsion cycle, which when repeatedly followed, allows for an endless forward sliding of the object. It was found that the maximum static friction between the object and the ground is the key factor that offers repeated support for the object to develop linear momentum in the beginning of every new cycle. The simulation is based on closed form analytical solutions of the ordinary differential equations for the unidirectional motion of the object to which the rotating masses are attached.

]]>Alireza Falahat

In this study, the influences of aspect ratio and Rayleigh number have been studied for a square cavity. The constant partial cooling at left vertical wall and partial heating at the right vertical wall along with the adiabatic top and bottom walls of cavity filled with the water. The aspect ratio was varied from 0.5 to 4. The governing equations are solved with finite volume approach for the range of Rayleigh number as 1000 to 1000000. Results have clearly indicated Heat transfer enhances with increasing of Rayleigh number for the whole of aspect ratio. The results show the Nusselt number increases from aspect ratio 0.5 to 1 and beyond that it decreases smoothly.

]]>Hashim N. Al-Mahmud Haider K. Mehbes and Ameen A. Nassar

This paper presents an efficient meshless method in the formulation of the weak form of local Petrov-Galerkin method MLPG. The formulation is carried out by using an elliptic domain rather than conventional isotropic domain of influence. Therefore, the method involves an MLPG formulation in conjunction with an anisotropic weight function. In the elliptic weight function, each node has three characteristic indicated that were major radius, inner radius, and the direction of the local domain. Furthermore, the space that will be covered by the elliptical domain will be less than the area of the circle (isotropic) at the same main diameter. This means leaving many points of integration are not necessary. Therefore, the computational cost will be decreased. MLPG method with the elliptical domain is used in solving problems of linear elastic fracture mechanism LEFM. MATLAB and Fortran codes are used for obtaining the results of this research .The results were compared with those presented in the literature which shows a reduction in the computational cost up to 15%, and an error criteria enhancement up to 25%.

]]>Ugo Icardi and Federico Sola

An accurate and cost effective zig-zag plate model with variable kinematics and fixed degrees of freedom recently developed by the authors, which a priori fulfills the stress and displacement continuity requirements, is applied to study indentation of sandwiches with honeycomb/foam core. The variable elastic properties of the core during crushing are evaluated apart and once at a time through a 3D finite element analysis. Shell elements with elastic-plastic isotropic properties are adopted to discretize honeycomb cores and faces, instead solid elements with nonlinear material behavior are used for foam cores. To keep low the computational burden, the structural response is computed in closed form by the zig-zag model using these elastic properties. The damage analysis is carried out through a mesoscale model that determines the degraded properties of failed regions in a physically consistent way. A good agreement with experiments taken from the literature being shown, the present simulation procedure with a low computational effort is proven to be an efficient alternative to the ones currently employed.

]]>Ashok Dargar

A comparative analysis of kinematic chains and their mechanisms at the conceptual stage of design is essential for the designers. There are large number of distinct chains available in each category, i.e., with specified number of links and degree of freedom. Chains with distinct structures can be expected to posses different characteristics which are not quite obvious. The designer must have some idea about the expected behaviour of the chain at least in comparative sense, so that he can pick up the best chain in order to obtain best performance. To accomplish this, the designer should be able to read the characteristics of the chain based on their topology. Using this belief, in the present work an attempt is made and a method is proposed to compare the chains from the effective utilization of link design parameters, quality of motion and function generation point of view. It provides a simple quantitative estimate to compare all the eligible chains. The concepts developed are applied to planar in- parallel robots, which are gaining in importance.

]]>Ashok Dargar

Structure synthesis of mechanisms is a pivotal issue in the field of mechanical innovation and mechanical conceptual design. The present work deals with problem of detection of isomorphism which is frequently encountered in structural synthesis of kinematic chains. A new approach based on a combination of eigenvalues and eigenvectors which are further associated with the modified adjacency matrix is proposed. The proposed method not only effective but also more efficient than that are based on the adjacency matrices and capable of detecting isomorphism in all types of compound KC, i.e. chains of single or multi degree of freedom with simple or multiple joints. This study will help the designer to select the best KC and mechanisms to perform the specified task at conceptual stage of design. Some examples are provided to demonstrate the effectiveness of this method.

]]>Luisa R. Madureira Elza M. M. Fonseca and Francisco Q. Melo

The objective of this work is to contribute with a simple and reliable numerical tool for the stress analysis of cylindrical vessels subjected to generalized forces using a mixed formulation. Variational techniques coupled with functional analysis are used to obtain an optimized solution for the shell displacement and further stress field evaluation using a combination of unknown analytic functions with Fourier expansions. A large cylindrical shell subjected to pinching loads is considered. These elements are intended to provide accurate modelling of the initially circular pipes response. Because of this behaviour, the bend’s cross-section abandons its original roundness, turning into an oval or noncircular configuration. In addition, the initially plane cross-section, tends to deform out of its own plane. These two deformation patterns are termed ovalization and warping, respectively. In this work the results for the radial displacement and section ovalization are analysed where the solution has six terms for an acceptable accuracy. The transverse displacement presents important dependence on the shell thickness vs radius, where in the case of thin shells the ovalization is restricted to a local area and this is the case analysed. The proposed method leads to accurate results with low complex input data. The conclusions of this work are that the definition of the load system and boundary conditions are easily processed as the method has pre-defined possibilities for each load case or edge boundary conditions. An analytic solution is obtained and a low number of terms in the Fourier series show good accuracy as can be seen by a comparison with finite element methods.

]]>Vibhor Baghel Sunil Chandel and R. Sivasankara Reddy

Gas turbine blades are cooled internally and externally and one widely used blade cooling technique is film cooling. In this type of cooling, relatively cool air is injected from the inside of the blade to the outside surface which forms a protective layer between the blade surface and hot gas streams. The present study is an attempt to establish the effect of blowing ratio and pressure ratio numerically on film cooling effectiveness in a typical nozzle guide vane with single hole on both pressure and suction surface of the vane. The commercially available CFD code “FLUENT” has been used after validating it against the experimental results reported in literature. Pressure ratio was varied from 1.1 to 1.2 with density ratio 2.0. Results obtained from the numerical investigation show that with increase in pressure ratio at constant blowing ratio, there was an increase in film cooling effectiveness. It is found that film spread is more on the pressure side as compared to suction side.

]]>Govind Maheshwari and Sumer Singh Patel

Several techniques on the Second Law of Thermodynamics have been used in the past for the analysis of Air standard Cycles. The terms used for these techniques include irreversibility analysis, entropy generation minimization, exergy analysis and thermodynamic efficiency. Entransy is a recently developed concept reflecting the heat transfer potential, rather than the ability to convert heat to work. This paper extends this concept to optimize thermodynamic processes of an irreversible Atkinson cycle. The entransy balance equation of thermodynamic processes is introduced, with which the concept of entransy dissipation is developed. For the irreversible Atkinson cycle where the working fluid is heated by the streams with prescribed inlet temperatures and specific capacity flow rates, it is found that the maximum entransy dissipation leads to the maximum output work, which is the maximum principle of entransy dissipation in thermodynamic processes. At the same time, it is found that minimum entropy generation alone could not describe change of the output work for the Atkinson cycle. The operation parameters are optimized for evaluating the maximum output work of Atkinson cycle by incorporating maximum entransy dissipation and minimum entropy generation when both, entransy dissipation and entropy generation, are induced by dumping the used streams into the environment is considered.

]]>András Mucsi

This paper deals with the effect of novel gripping systems developed for tensile testing on the stress distribution inside the test piece. The uniformity of the stress distribution plays a decisive role in measuring the upper yield strength and creep behavior of materials. In this study two modified versions of a recently developed gripping system are introduced and tested together with the original version. The tests consist of measuring the bending stress/axial stress ration during elastic loading of the test piece. The bending stress/average stress ratio was measured using a special strain gauge mounted test piece, which was loaded by elastic tension. The results show that the gripping systems provide the self-alignment of the test piece at the beginning of the loading; therefore they can ensure almost true uniaxial conditions for tensile testing. The average bending stress/axial stress ratio is found to be just 1-2 %, so, the gripping systems can provide the accurate measurement of upper yield strength and creep curves of materials.

]]>Sumaia Parveen Shupti Rumia Sultana Mir Golam Rabby and Md. Mamun Molla

In this paper, numerical simulation has been performed to study the flow behavior of a pulsatile Newtonian fluid confined within a two-dimensional (2D) channel with an asymmetric shaped aneurysm using the finite volume method. The governing Navier- Stokes equations have been modified using the Cartesian curvilinear coordinates to handle complex geometries. The investigation have been carried out to characterize the blood flow for Reynolds number 100, 300 and 500 which is suitable for human artery. The numerical results are represented here in terms of velocity, pressure distribution, wall shear stress as well as the streamlines indicating the recirculation zones inside the dilated region. The results of this study demonstrate a lower centerline velocity inside the aneurysm but comparatively higher wall pressure and wall shear stress at the distal neck of the aneurysm. Furthermore, all three Reynolds numbers show the presence of vortex inside the bulge.

]]>Puran Singh Anil Kumar and Mahesh Vashisth

A robot is a system combining many subsystems that interact among themselves as well as with the environment in which the robot works. In robotics, end effectors are a device at the end of a robotic arm, designed to interact with the environment. Gripper is an end effectors or tool to grasp any physical thing that may be a human hand or any instrument. To achieve this goal we intend to incorporate a simple linkage actuation mechanism. An AC motor is used along with spur gears and a threaded shaft arrangement. The gripper can perform the basic function of picking, holding and grasping of objects by means of a DC motor and it forms the mechanism for the spot welding. The human hand design forms the basis of this project of developing a robotic gripper and is the source of inspiration to achieve the sufficient level of dexterity in the domain of grasping and manipulation if coupled with wrist and arm.

]]>M.A. Rahmat R.N. Ibrahim and R.H. Oskouei

In this study, stress raisers (notches, fretting fatigue and a combination of notch and fretting) were taken into consideration as to its performance in reducing fatigue life. Reduction factor measurements using fatigue sensitivity, q as an effect of the respective stress raiser on fatigue lives were done. Finite element analyses on the consequence of clamping pressure on a notched geometry revealed a further increase in stress concentration at the notch tip for this specific geometry. However, fatigue tests revealed no significant difference in the fatigue lives between the notched and the combined notch and fretting fatigue. Fatigue notch sensitivity, q_{n} was found to be between 0.42 and 0.65 while a fretting notch-like sensitivity, q_{f} calculated from fretting fatigue results using a method by Wharton et al were 3.52 and 3.28 at torque levels 20 Nm and 50 Nm respectively. It was found that the stress concentration factor, k_{t} for the fretting condition was conservative in its value and did not correlate well with the actual fretting reduction factor, k_{f}. Finally, fractorgraphic analysis revealed significant wear for both fretting fatigue specimens and the combined notch and fretting fatigue. However, cracks were only found to originate from the notch tip for the combined notch and fretting fatigue at all alternating stress levels.

S.K. Rout Ahmed Kadhim Hussein R.K. Sahoo S.K. Sarangi and M. Hasanuzzaman

This research article illustrates a numerical study of single stage coaxial as well as inline Inertance-Type Pulse Tube Refrigerator (ITPTR). In this present work a computational fluid dynamic (CFD) approach has been adopted for numerical simulation purpose. The detail analysis of cool down behaviour, heat transfer at the cold end and the pressure variation inside the whole system has been carried out by using the most powerful computational fluid dynamic software package FLUENT. A number of cases have been solved by changing the porosity of the regenerator from 0.5 to 0.9 while the rest of the considered parameter is remains unchanged. The operating frequency for all the studied cases is (34 Hz) while the other system dimensions and the boundary conditions are considered unchanged for all cases. The results show that the porosity value of (0.6) produces a better cooling effect on the cold end of the pulse tube refrigerator. The variations of the pressure inside the pulse tube refrigerator during the process are also analysed. In this work an attempt has been made to make a thermally non-equilibrium model applied numerically to the porous region by considering two different energy equations to the solid matrix and for the fluid inside the porous medium and the results are compared with the thermally equilibrium model. In fact, to get an optimum parameter experimentally is a very tedious for iterance pulse tube refrigerator job, so that the CFD approach gives a better solution which is the main purpose of the present work. In the next part the fuzzy logic approach is applied to optimize the different component parameters that affect the cooling performance of the ITPTR. The investigation is performed with different design parameters such as the length and diameter of pulse tube and regenerator given as an input to the fuzzy controller while the output from the controller is the cold end temperature. The predicted optimum results have been verified by performing the confirmation tests.

]]>Dariush Semnani

Weft knitted fabric structures have got new application in the modern technical textile such as seat belt and packaging fabrics. The weft knitted fabric is applied for technical textiles commonly as composites to resist against tension along courses direction in jamming status. In this study, mechanical properties of weft knitted fabrics with different structures of single jersey and double jersey in fully stretched status of jamming were considered by geometrical modeling. Ultra high tenacity nylon 6.6 yarn was used in manufacturing of weft knitted fabrics. Consequently the tenacity of the sample fabrics is assessed by a tensile tester. Mechanical properties of the fabrics are compared with theoretical modeling. The results show that the weft knitted fabrics with Rib structure have a superior tenacity. Also, double jersey fabrics of Full Cardigan and Full Milano represent better mechanical properties in comparison with single jersey fabrics.

]]>Minhaj Ahemad.A.Rehman R. R Shrivastava and Rakesh. L Shrivastava

Green manufacturing (GM) is a term used to describe manufacturing practices that do not harm the environment during any part of the manufacturing process. It emphasizes the use of processes that do not pollute the environment or harm consumers, employees, or other members of the community. GM stresses on reducing parts, rationalizing materials, and reusing components, to help make products more efficient to build. This paper presents the details of a case study. It highlights the road map of the company for achieving performance improvement through GM implementation and its impact on organizational performance. It also points out strengths and weaknesses of GM implementation practices and overall performance using developed research instrument. The case study helps in evaluating the company’s GM implementation and overall business performance. To do so, research instrument was administered amongst forty one employees in the companies respectively and their responses were analyzed. Using the data obtained from a survey of industries in India, the identified factors were subjected to appropriate statistical tests to establish reliable and valid model. Statistical computing package SPSS 17.0 for Windows was used for reliability and validity analysis. The validated instrument of GM factors developed here may be used by manufacturing organizations to priorities their management efforts to assess and implement GM. The validated results are in Indian context; however, the instrument developed can be used in global context.

]]>Ali Hasan

Kinematic chain is a combination of links connected by different kinematic pairs (joints). The study of the nature of connection among various links of a kinematic chain is known as structural analysis or topological analysis. In this paper to help the analysis, several methods of representation of the kinematic structure are presented. The study includes the functional schematic representation, structural representation, graph representation, and various matrix representations. The study is extremely useful for designer at the conceptual stage of design and research scholars in the initial stage of their research work.

]]>Jin Tao Qing H. Qin and Leilei Cao

A novel numerical model is developed for evaluating the temperature distribution on a two-dimensional skin tissue. The method is based on a combination of Laplace transform and meshless method as well as on the Pennes bio-heat equation. It is the first time to combine Laplace transform and RBF-MFS to study the performance of heat transfer in skin tissue governed by Pennes equation. First, Laplace transform of Pennes bio-heat equation is applied to handle the derivative of time variable. Then, the particular solution is approximated by a linear combination of radial basis functions, and the homogeneous solution is approximately determined by the method of fundamental solution. The multi-subdomain RBF–MFS technique is implemented for analyzing problems containing different materials and/or multi-connected regions. The last step of the algorithm is the inverse Laplace transforms from Laplace domain to time domain. The efficiency and availability of the proposed method is assessed by several examples including healthy tissue, tissue with tumour and burned tissue.

]]>Lun-Shin Yao Md. Mamun Molla and S. Ghosh Moulic

A fully-developed flow of a non-Newtonian pseudoplastic fluid through a circular pipe has been studied using a four-parameter model, as an example, for the shear-rate dependent apparent viscosity. The model used in this investigation is a modification of the two-parameter Ostwald-de Waele power law [1], which correctly represents the lower and upper regions of Newtonian behavior characteristic of pseudoplastic polymer melts and solutions. Since there has only one set complete experimental data available for the shear-rate dependent viscosity, we use them to show that a perfect match can be achieved between the modified power-law viscosity model and the experimental data. Such a perfect match is required for an accurate prediction of the flow behavior in internal flow problems.

]]>S. R. Kumbhar Subhasis Maji and Bimlesh Kumar

Magneto rheological elastomer (MRE) is a new kind of smart materials. Its dynamic mechanical performances can be controlled by controlling an applied magnetic field. MRE is usually used as stiffness - changeable spring in the semi-active vibration absorber. In order to get perfect vibration control effect, low dynamic damping of MRE is needed. This paper presents a new method of fabricating isotropic MREs under normal temperature and pressure conditions. In the absence of a magnetic field, a variety of MR elastomer samples were prepared using Sylard’s184 silicone elastomer along with un-annealed electrolytic iron power 500 mesh and 15 micron size. Their dynamic characteristics like fractional change in resonant frequency and fractional change in have been studied. The effects of iron particles and the applied magnetic field were investigated. This study is also expected to provide a good guide for designing and preparing new MR elastomers.

]]>Sandeep R. Desai and S Pavitran

Very first step in the analysis of fluid elastic vibrations of heat exchanger tubes is determination of modal parameters (natural frequency and damping ratios) of the tubes. Natural frequencies and damping ratios of the tubes are very important parameters as critical velocity at instability also depends on them. Lower natural frequencies are desired so as to achieve the fluid elastic instability with limited flow capacities of the pump. This paper presents part of the research work to analyze fluid elastic vibrations of finned tubes subjected to single and two phase cross flows of water and air-water. It consists of determination of modal parameters of finned tubes for two different fin pitches (2.54 and 6.35 mm). The work also consists of determination of modal parameters for finned tube attached with welded rods of 220 mm length to reduce natural frequencies. It helps to know how fin tube parameters affect the natural frequency and damping values and hence their proneness to fluid elastic vibration. Further, as a requisite for easy conduct of experiments on fluid elastic vibration analysis of finned tubes, it is found that, natural frequencies of 56 and 65 Hz of fin tubes are reduced to 14 and 17 Hz respectively when solid rods of 220 mm length are welded to them.

]]>Amal Nassar and Eman Nassar

The purpose of this research is to try getting use of each possible power source to get a car moving with the minimum running cost and minimum damage to the environment.

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