Latest issue

by M. Altosole, D. Boote, S. Brizzolara, M. Viviani

Vol. 7. n. 7, pp. 1234-1245

Abstract - The paper is focused on some benefits gained by the integration of CFD results into the simulation process over time, in order to develop a whole numerical model representing the dynamics of a large merchant ship during towing/escorting operations in severe weather conditions. In particular, the shown application is referred to the simulation of a container ship, towed by two tugboats in a typical Mediterranean harbor. The developed simulator consists of a set of ordinary differential equations, mathematical relationships and numerical tables which represent the ship and the propulsion system dynamics, while CFD method is used in order to model the wind forces, eventually influenced by the presence of some harbor breakwaters, acting on the considered ship. The proposed simulator can be used as a powerful tool to plan safer towing arrangements and procedures, or to analyze in post-processing possible human errors in the case of unfortunate marine accidents.

Keywords: CFD, Ship Dynamics, Time Domain Simulation, Towing Operations, Wind Action.

by Hassene Djemel, Mounir Baccar, Mohamed Mseddi

Vol. 7. n. 7, pp. 1246-1252

Abstract - This study concerns the numerical simulation in two dimensions; air flow and heat transfer in a horizontal channel with isothermal walls with four pairs of fins. A computational fluid dynamics (CFD) program FLUENT has been used to compute the velocity and the temperature field. Computation is performed by means of a finite volume approach based on a pressure correction procedure. The fluid considered here is air (Pr = 0.71) and the analysis is carried out for Reynolds numbers ranged between 50 and 300. The objective of the proposed work is to analyze the flows caused by the presence of fins. Thus the effects of Reynolds number and the angle of the fins are presented and discussed.

Keywords: Forced Convection, Thermal Transfer, CFD, Finite Volume Method .

by Mohamed A. El Sayad

Vol. 7. n. 7, pp. 1253-1262

Abstract - This paper presents a fully coupled fluid-structure-soil interaction analysis technique for rectangular liquid-contained structures subjected to horizontal ground excitation. The hydrodynamic interaction of the contained liquid with the structure can be considered as impulsive pressure loads exerted on the wetted interface during ground excitations of earthquake waves. The intensity of the horizontal ground forces is found to be independent upon the response of the system, which is known as external excitation. The multiple time scale method is used to construct a first order uniform expansion yielding two first order non-linear ordinary differential equations governing the modulations of the amplitude and phase angle for the two resonance modes of external excitations. When the first and second mode is externally excited separately, the results show that amplitude response can reach the steady state and unsteady chaotic behavior in the same time depending upon the initial conditions and external detuning parameter σ_x . The system response of the steady state amplitude can also take multiple values according to initial conditions within a certain range of the external detuning parameter. The response of steady the amplitude behaves as stable and unstable oscillator within a certain range of σ_x as soft or hard non-linear system. The unsteady amplitude is taking the chaotic behavior of the non-linear system in different forms varying with σ_x. The results are indicating that strong non-linearities which introduced due to impact and high non-linearity can suppress the amplitude and domain of fluctuations in the two resonance modes of excitations.

Keywords: Ground Earthquake Excitations, Liquid Impact Sloshing, Pendulum Modeling, External Excitations.

by A. N. M. Khalil, M. F. M. A. Hamzas,M. S. Hussin, Z. A. Zailani, A. B. Sanuddin

Vol. 7. n. 7, pp. 1263-1268

Abstract - This paper is to investigate the tensile strength of new palm oil based wax/HDPE/Palm oil fiber blends was investigated by using 23 factorial design experiment. The palm oil based wax exhibits the potential of replacing the existing industrial blue wax which apply in prototype making. The industrial blue wax is widely used to produce part prototypes from the machining process. Hard and self-lubricating are the factors which this material are has been choosing in the industries and educational purposes. The. Hardness results has been taken to compare with the industrial blue wax. The result shows that the tensile strength of new palm oil based wax/HDPE/Palm oil fiber blend was obtained is higher compared to the existing industrial blue wax. However, since the cost of this new palm oil based wax is lower, it will be an attractive option to replace the existing industrial blue wax for prototype application.

Keywords: Machinability, Palm Oil, Industrial Wax, HDPE, Prototype.

by Nor Azwadi Che Sidik, Siti Aisyah Razali

Vol. 7. n. 7, pp. 1269-1274

Abstract - The lattice Boltzmann method (LBM) has evolved to become a well accepted as a useful method to simulate various fluid behaviors. In the meantime, research toward the heat transfer enhancement due to the use of nanofluid using lattice Boltzmann method has recently become attention for many researchers. This paper intends to provide a brief review of researches on application of lattice Boltzmann method on the prediction of nanofluid and identifies opportunities for future research.

Keywords: Heat Transfer, Lattice Boltzmann Method, Nanofluid, Nusselt Number .

by Maria_Esther Sbampato, Carla Fernandes, Luiz G. Barreta, Cristiane A. Martins

Vol. 7. n. 7, pp. 1275-1283

Abstract - The presence of an acoustic actuation can drastically change the structure of a diffusion flame produced in a cylindrical burner. This work presents a spectroscopic study of the soot and instable radicals (CH* and C2*) chemiluminescent emissions in an acoustic excited jet diffusion flame of Liquefied Petroleum Gas - LPG. Frequencies from 500 Hz to 600 Hz and sound pressures between 490 Pa and 2730 Pa were employed. Planar Image Velocimetry (PIV) experiments were carried out in order to understand the acoustic effect in the velocity field profile. Frequency of 575 Hz and 600 Hz conditions presented more effective acoustic performance, making the flame begin to show characteristics of a partially premixed flame. A reduction in the soot emission and an increase of the instable radicals were also observed. The PIV results showed a sequence of periods of expansion and compression of the fuel with the acoustic actuation, what led to an increased rate of air-fuel mixture, changing the flame structure.

Keywords: Acoustic Excited Flame, Soot, CH Radical, C2 Radical and LPG Flame.

by Nor Azwadi C. Sidik, Aman A. Khan

Vol. 7. n. 7, pp. 1284-1286

Abstract - This paper presents numerical predictions of drag parachutes using commercial software. Two models of drag chutes with different projected area were selected to examine their flow dynamics parameters such as drag coefficient, drag force and flow characteristics downstream the drag chutes. Turbulent ranges of flow speed were considered. It was seen that the improved version of drag chute gave more stability in flow dynamics compared to the conventional type of drag chute.

Keywords: Drag Chute, FLUENT, Flow Dynamics, Turbulent Flow.

by Leila Jahanshaloo, Nor Azwadi Che Sidik

Vol. 7. n. 7, pp. 1287-1290

Abstract - LBM is an effective computational technique for fluid dynamics based on kinetic theory. In recent years, transient and turbulent flow simulation by using this new class of computational fluid dynamics method has attracted more attention. In this paper a two dimensional lid driven cavity flows at different Reynolds number (1000-7500) are simulated by using multi-relaxation Lattice Boltzmann (MRT-LBM) and single relaxation time (SRT) model in the LBGK method. The results are compared with previous published papers which solve the Navier-Stokes equation directly. The model predicts the flow characteristics, such as circulating flow and velocity successfully. The comparisons between the simulated results show that the lattice Boltzmann method has the capacity to solve the complex flows with reasonable accuracy and reliability.

Keywords: Two-Dimensional Flows, Lattice Boltzmann Method, Turbulent Flow, MRT, SRT.

by P. Loganathan, C. Vimala

Vol. 7. n. 7, pp. 1291-1298

Abstract - An analysis has been carried out to investigate an unsteady two-dimensional hydromagnetic nanofluid flow past an exponentially stretching sheet in the presence of thermal radiation and heat generation/absorption. The governing time-dependent partial differential equations are transformed into ordinary differential equations, using an appropriate similarity transformation. The resulting ordinary differential equations are solved numerically using the shooting method. The effects of the governing parameters on the flow and heat transfer characteristics are analyzed and presented graphically. Different types of nanoparticles, namely, Cu, Ag, CuO, Al2O3 and TiO2 with water as the base fluid, are studied. It is found that the flow field and temperature are significantly influenced by the volume fraction of nanoparticles, radiation, heat generation, heat absorption and the magnetic effects. Comparisons with previously published works are performed in some special cases, and found to be in good agreement.

Keywords: Thermal Radiation, Unsteady Flow, Exponentially Stretching Sheet, Heat Source, Heat Sink, Nanofluid.

by N. Nagarajan, G. Nagarajan

Vol. 7. n. 7, pp. 1299-1313

Abstract - Vegetable oils offer almost the same power output with slightly lower thermal efficiency when used in diesel engines. Neem oil being non-edible could be regarded as an alternative fuel for compression ignition engines. Vegetable oils like neem oil are available in rural areas and have high cetane number and calorific value quite close to that of diesel fuel. The uses of any vegetable oils have some problems when subjected to prolonged usage in diesel engines. The problems are attributed to high viscosity, low volatility and poly unsaturated character of neat vegetable oils. Higher viscosity of vegetable oils causes improper atomization of fuels during injection and result in incomplete combustion. The viscosity of neem oil is reduced by transesterification to obtain neem oil methyl ester. Application of bio-fuel derived through trans-esterification of Neem oil is prevalent in diesel engines since it has fuel economy and reduction of emission of exhaust gases. In the present study necessary efforts have been made to prepare a bio-fuel through trans-esterification from raw neem oil to study the performance, combustion analysis and emission characteristics. The derived fuel called “NEEM OIL METHYL ESTER” (NOME-C17H34COOCH3) has been used in a single cylinder water cooled diesel engine under standard operating conditions. The experimental investigations were carried out to assess the combustion analysis, performance and emission levels of the engine using NOME and its blends with diesel. The brake thermal efficiency of NOME is found to be much higher than diesel due to improved combustion lubricity and reduced friction. The NOx level, the exhaust gas temperature and HC for NOME are found to be higher than diesel due to efficient combustion, lower viscosity and good mixture formation. The smoke is also found to be lower than diesel, because of excess oxygen present in the bio-diesel. Under combustion analysis heat release rate, rate of pressure rise, and cylinder pressure were calculated, plotted and curves were drawn for diesel fuel, NOME and its blends with diesel and compared with diesel fuel. The heat release rate is slightly higher for NOME compared to diesel because of better premixed combustion and increases NOX emissions. Adiabatic flame temperatures were also calculated for NOME and its blends with diesel. The adiabatic flame temperature is reduced drastically with excess air for diesel, NOME, B20 and B30. It is found that adiabatic flame temperature of B20 is close to diesel.

Keywords: Adiabatic Flame Temperature, Bio-Fuel, NOME, Transesterification.

by P. Loganathan, C. Sivapoornapriya

Vol. 7. n. 7, pp. 1314-1322

Abstract - The fundamental study of the phenomenon of natural convective heat and mass transfer near a vertical plate in the presence of porous medium is investigated. The fluids considered in the discussion are air and water. The unsteady, coupled, non-linear partial differential equations are solved numerically by Crank Nicolson scheme. The influence of various parameters like velocity, temperature and concentration are analyzed. The skin friction, the Nusselt number, the Sherwood number, average skin friction, average Nusselt number and average Sherwood number are also presented graphically for both air and water. It has been observed that velocity components increase with permeability parameter where as temperature and concentration decreases with it. An analysis is performed to check the stability and the convergence of the finite difference scheme which converges faster and unconditionally stable.

Keywords: Finite Difference, Stability, Heat Transfer, Mass Transfer, Porous Medium.

by Dimitrios G. Pavlou, Kyriakos I. Kourousis

Vol. 7. n. 7, pp. 1323-1328

Abstract - The life of composite materials (CM) subjected to fatigue conditions is associated with the gradual damage of their structure. Since the damage accumulation is reflected by changes in CM properties, the derivation of damage accumulation curves may be based on test results providing the reduction of the residual strength. Examined in this work is a non-linear fatigue damage accumulation function for cross-ply CF/PEEK laminates. This damage function is specified with respect to damage parameters derived by the strength decrease during fatigue for the CF/PEEK. Taking into account this concept, an improvement of the theory of isodamage lines is proposed. Since the nonlinearity of the derived damage function depends on an exponent that is a function of the fatigue stress amplitude, the effect of the loading order and the previous damage history on the total fatigue life is investigated. Numerical examples of fatigue life prediction under two-stage loading conditions and a damage accumulation map for the CP/PEEK are presented and discussed.

Keywords: Damage, Fatigue, CF/PEEK, Residual Strength, Non-Linear Model, Two-Stage Loading.

by Carlos Alberto Dutra Fraga Filho, Fernando César Meira Menandro Rivânia Hermógenes Paulino de Romero, Juan Sérgio Romero Saenz

Vol. 7. n. 7, pp. 1329-1339

Abstract - The objectives of this work were: to design and build material specimens which behave, under mechanical loading, such as functionally graded materials; to perform dynamic vibration tests on the produced specimens, and; to numerically simulate the vibration tests in order to validate a proposed numerical model for functionally graded materials characterization. The work was divided in the following phases: confection of the specimens; adoption of the composite beam model for the produced specimens; preparation and execution of the vibration laboratory tests; mathematical modeling for the analytical resolution of the composite beam vibration problem; definition of the numerical model to be applied to the problem; execution of the numerical simulation of the dynamic tests, and; comparative analysis between the analytical, experimental, and numerical results. The experimental, analytical, and numerical tests present similar results for all specimens. Natural vibration frequencies, whether obtained by any means (experimental, analytical, or numerical) differ not more than 15.4%. The proposed numerical method presents itself, thus, adequate for layered material modeling.

Keywords: Elastic Properties, Finite Element Analysis (FEA), Functional Composite, Modelling, Vibration.

A. B. Sanuddin, M. S. Hussin, H. Azmi, Z. A. Zailani, M. F. M. A. Hamzas, V. Kartik

Vol. 7. n. 7, pp. 1340-1346

Abstract - Metal matrix composites (MMCs) have become attractive in a variety of applications due to its advantage of having intermediate properties between metal and ceramic. This paper presents the investigation of the effect of sintering duration on mechanical properties of Al/SiC composites. In the present work, SiC particle reinforced Al matrix composites were produced via powder metallurgical processing. Pure aluminium powder with a particle size of 63 μm and silicon carbide powder with a particle size of 37μm were used. The range of sintering duration was 1, 2, 3, 4, 5 and 6 h at a fixed temperature of 590 ºC. The compressive, hardness and impact tests were performed on the sintered samples to characterize the mechanical properties. It was found that as the sintering duration increased from 1 to 6 hours, the mechanical properties of the samples were enhanced. Furthermore, microscopic observations showed that the porosity level decreased as the sintering duration was increased.

Keywords: Aluminium Based Composite, Sintering Duration, Powder Metallurgy, Mechanical Property.

by M. Mahendra Boopathi, K. P. Arulshri, P. Shanmughasundaram

Vol. 7. n. 7, pp. 1347-1354

Abstract - Metal Matrix Particulate Composites have become as a potential material particularly for automotive and aerospace applications. In view of the growing engineering applications of composites, the machining parameters must be optimized to achieve the good surface quality, reduced tool wear and cutting forces. In this paper, the effect of the feed, spindle speed and step drill material on the exit burr height and surface roughness have been analyzed. Experimental study was conducted for Al- SiC – fly ash hybrid composites which are fabricated through the stir casting method. Optimum drilling parameters were identified by employing Taguchi method and ANOVA techniques. The results were validated by confirmation test. Results revealed that feed, spindle speed and step drill materials are the most significant factors on the burr height and surface roughness. Dynamometer was used to evaluate the thrust that was being applied to the work piece when it was drilled.

Keywords: Metal Matrix Particulate Composites, Step Drilling, Exit Burr Height, Surface Roughness, Thrust Force.

by P. Senthil Kumar, K. Manisekar

Vol. 7. n. 7, pp. 1355-1361

Abstract - In this study, MoS2 added copper-tin alloy was made by powder metallurgy method. The friction and wear characteristic of the produced composites was evaluated by using pin-on-disc apparatus. It has been found experimentally that a loss in mass due to wear with two loads and two sliding speeds for two sliding distances. Based on the design of experiment, the influence of the percentages of reinforcement, load, sliding distance, and sliding speed on both the friction coefficient and specific wear rate were calculated. Analysis of variance (ANOVA) used to examine the influence of the parameters on both the wear rate and the coefficient of friction. From this study, it is noted that coefficient of friction of the composites decreased considerably with the addition of MoS2. The load and weight percentage of MoS2 are the most significant parameters that affect the specific wear rate and where as load is the control factor for coefficient of friction. The 7 wt.% of MoS2 composites exhibited a very low coefficient of friction. The observations reveal that the specific wear rates of the composites decreased considerably with the addition of MoS2.To study the wear morphology, SEM, worn surface analysis and EDS is used.

Keywords: Powder Metallurgy, Molybdenum Disulfide, Wear Loss, Metal Matrix Composites.

by M. Muthu Krishnan, K. Marimuthu

Vol. 7. n. 7, pp. 1362-1365

Abstract - Fusion welding of aluminium alloys results in solidification cracking, porosity etc. which affects the properties of the weldment.Fricition stir welding is the solid state welding process which is widely used in welding of aluminium alloys. It overcomes the defects of fusion welding process in improving the properties of the joints. The current paper focus on studying the tensile properties of the dissimilar friction stir welding of aluminium alloys AA6063 and A319 .Three different tool profiles (square, hexagonal and cylindrical) with three welding speeds (25, 30, 35 mm/min) and three tool rotational speeds (1000, 1200 and 1300 rpm) have been used in studying the joint properties of the weld. Higher tensile strength was obtained for the parameters of square tool profile, 25 mm/min and 1300 rpm.

Keywords: Aluminium Alloys, FSW, Welding Speed, Rotational Speed, Tensile Strength, Hardness.

by V. Rathinam, T. Kannan

Vol. 7. n. 7, pp. 1366-1377

Abstract - Cladding is the most economical process used on the surface of low carbon structural steel to improve the corrosion resistance. The corrosion resistant property is based on the amount of ferrite present in the clad layer. Generally, the ferrite content present in the layer is expressed in terms of ferrite number (FN). The optimum range of ferrite number plays an instrumental role to bring adequate surface properties like chloride stress corrosion cracking resistance, pitting and crevice corrosion resistance and mechanical properties. For achieving maximum economy and enhanced life, duplex stainless steel (E2209T1-4/1) is deposited on the surface of low carbon structural steel of IS: 2062. The problem faced in the weld cladding towards achieving the required amount of ferrite number is the selection of an optimum combination of input process parameters (welding current, welding speed, contact tip to specimen distance and gun angle). This paper mainly concentrates on estimating FN and analysis of input process parameters on FN of heat treated duplex stainless steel cladding. To predict FN, mathematical equations was developed based on four factor five level central composite rotatable design with full replication using regression methods. In this paper, artificial neural network (ANN) and genetic algorithm (GA) techniques were integrated and labeled as ANN-GA to identify the optimum process parameters in FCAW to get maximum FN. From the results, the integrated ANN-GA (I OR II) is capable of giving maximum FN at optimum process parameters compared to that of experimental, regression and ANN modeling.

Keywords: Duplex Stainless Steel, Flux Cored Arc Welding, Ferrite Number, Artificial Neural Network, Genetic Algorithm and Heat Treatment.

by Z. Nooraizedfiza, H. Salmah, M. A. Omar

Vol. 7. n. 7, pp. 1378-1383

Abstract - Metal injection molding (MIM) becomes a well-established and promising technology for small and mass production. Feedstock characterization is one of the most important roles in ensuring the properties of the MIM products. Rheology study is compulsory in characterize the feedstock for matches the range of viscosities encountered in practice. The shear rates for molding normally exceed the range obtainable with the rheometer. In this study, the rheological properties and behaviors of magnesium metal injection molding feedstock was investigated. The paraffin wax (PW), high-density polyethylene (HDPE), and stearic acid (SA) were used as the binder for magnesium MIM feedstock. A Brabender Plastogram EC PLUS was used to prepare the magnesium MIM feedstock, and the rheological properties of the resulting feedstock were evaluated by the capillary rheometry. The effect of the relation of shear rate and temperature on viscosity for magnesium MIM feedstock has been investigated. The rheological results exhibited the pseudoplatic behavior. The flow behavior index (n) obtained was less than 1. The viscosity (η) of the magnesium MIM feedstock decreased with increasing shear rate (γ). The magnesium MIM feedstock viscosity also decreased with increasing temperature and found to be suitable for injection molding.

Keywords: Rheology, Metal Injection Molding, Magnesium Powder, Paraffin Wax, High Density Polyethylene, Stearic Acid.

by Štamborská M., Fajkoš R., Kvíčala M.

Vol. 7. n. 7, pp. 1384-1391

Abstract - The identification of the material properties in sheet metal is usually achieved using uniaxial tests performed along different texture directions. The article focuses on the comparison of strain fields and stress fields for different directions of rolling. Notched specimens made from anisotropic material were used for the identification of strains in the plastic area. That geometry generates a heterogeneous strain field which has been measured during the test using a digital image correlation system. The advantage of using a heterogeneous strain field in the identification procedure is that a complex state of stress–strain can be analyzed at the same time and much more information can be obtained in a single test. On the other hand the stress field cannot be directly computed from the test and a suitable identification procedure has to be developed. Here, the virtual fields method (VFM) adapted for plastic strain has been used to identify the hardening behaviour and the anisotropy of the material. The values obtained with the VFM have been compared with the results coming from a standard identification made with uniaxial tensile tests for different directions of rolling.

Keywords: Anisotropic Hardening Coefficient, Digital Image Correlation, Virtual Fields Method.

by Saroj Kumar Sarangi, B. Basa

Vol. 7. n. 7, pp. 1392-1401

Abstract - This paper addresses the active control of mechanical vibrations induced in laminated composite doubly curved shells. A three dimensional energy based finite element model has been developed for this analysis. The laminated shell is integrated with a patch of active constrained layer damping (ACLD) treatment in which vertically reinforced 1-3 piezoelectric composite is used as the material of the constraining layer. Both in-plane and out-of-plane actuations of the constraining layer of the ACLD treatment have been utilized for deriving the finite element model. Investigation has been carried out to see the performance of the patch when the orientation angle of the piezoelectric fibers of the constraining layer is varied in the two mutually orthogonal vertical planes. The analysis revealed that the vertically reinforced 1-3 piezoelectric composites which are in general being used for the distributed sensors can be potentially used for the distributed actuators of high performance light-weight smart composite shells.

Keywords: Vibration Control, Smart Structure, Composite Shells.

by J. Marty, P. Kulisa, R. Barrier

Vol. 7. n. 7, pp. 1402-1412

Abstract - A numerical assessment of unsteadiness and information losses due to boundary conditions, especially the rotor-stator interface treatment in an axial high pressure compressor (HPC) is proposed. Steady and unsteady computations are performed on a three-stage axial HPC with a 3D Navier-Stokes code. The steady simulation is based upon periodic boundary condition for azimuthal frontiers and the mixing plane approach which averages circumferentially the information coming from the adjacent blade row. The unsteady one uses the phase-lag method for both azimuthal frontiers and rotor-stator interface. The unsteady simulation highlights the wake effects in the stator passage due to the wakes released by the rotor and the potential effects on the wall pressure of the rotor blades due to the stator blades. The comparison between the steady and the time-averaged unsteady simulations shows a good agreement in the information transfer at the rotor-stator interface. The main discrepancy appears in the static pressure field on the rotor side of the interface, due to the inability of the steady computation to capture the potential effects. The radial profiles and the performances obtained with these two simulations are very similar. Thus a steady computation results in flow field and performance predictions with a sufficient accuracy. This comparison confirms the validity of using the mixing plane approach for HPC design.

Keywords: Axial Compressor, Phase-Lag Method, Rotor-Stator Interaction, Mixing-Plane Method.

by F. A. Ali, F. A. Azis, M. S. M. Aras, Muhd Nur Othman, S. S. Abdullah

Vol. 7. n. 7, pp. 1413-1420

Abstract - This paper describes a design and development of magnetic contactless thruster for Unmanned Underwater Vehicle. The thrusters are one of the most critical underwater technologies that define ROVs overall performance in term of speed. In a non-controllable environment such as sea, the thrusters faced the certain problem such as over pressure, corrosion and shatter. These all will lead leaking to the thrusters. A magnetic contactless of underwater thruster which called TUSHEE thruster is designed to avoid the occurrence of such problems. The CAD software is used as a tool to design these all parts of TUSHEE thruster. The thruster is designed and fabricated into two separate parts which are housed for motor and housing for propeller. Both parts have a plate that holds a magnet. Both plates are printed by using rapid prototyping machine. The rare magnetic material called a Neo magnet with size 2.0 cm for height and 1.3 cm in diameter is used. The 12V Brushless DC motor and 4 blade propeller with 10 cm diameter is chosen for this thruster. PVC is used for both housing with 11.1 cm diameter each. All these materials are chosen based on some criteria such as performance and price. The experimental test is done by the thruster at the swimming pool and laboratory pool. The thruster moves forward with speed 0.214 m/s and the propeller is rotated with 231 RPM. The results from these trials and demonstrations are recorded and shown.

Keywords: Magnetic Contactless Thruster, Neo Magnet, Air Gap.

by P. D. Jeyakumar, G. Devaradjane

Vol. 7. n. 7, pp. 1421-1426

Abstract - To identify the highest energy-absorbing geometrical section of thin-walled steel tubes is the objective of this study. Energy absorption in square, circular, pentagonal and hexagonal steel tubes were evaluated by finite element analysis. With the impactor colliding with one side of the tube while its other side kept rigid, a three-dimensional simulation was accomplished. The study showed that energy absorption in the pentagonal cross-section was higher than in other three cross-sections. The experimental results of load displacement with square steel tube showed good agreement with finite element method. The study suggests that a pentagonal structure of crush box would avoid higher impact and hence minimize damage to the automotive structure.

Keywords: Finite Element Method, Crush Box, Energy Absorption, Automotive Structure.

by Semin, Rosli Abu Bakar

Vol. 7. n. 7, pp. 1427-1438

Abstract - This research methodology has been explained step-by-step and in detail for the simulation and experimental investigation of compressed natural gas engine performance. The engine simulation model was developed to investigate engine performance based on computational simulations. The engine computational simulation model has been using one dimensional model. The experiment investigation was conducted based on ISO 3046. The experiment has been using eddy current dynamometer engine test bed. The simulation and experiment was performed to investigate engine performance parameters such as intake pressure and temperature, cylinder pressure and temperature, torque, power, break mean effective power, specific fuel consumption and exhaust pressure and temperature.

Keywords: CNG Engine, Eddy Current Dynamometer, Engine Performance, Research Methodology, Simulation.

by F. Tiss, T. Ghabara, R. Chouikh, A. Guizani

Vol. 7. n. 7, pp. 1439-1445

Abstract - In this work a two-dimensional non isothermal computational fluid dynamics model of PEM fuel cell is developed by considering the electrochemical, electrical, mass, and heat transfer. This model links transport phenomena of species with electrochemical characteristics and structural properties, and provides PEM fuel cell performance. The mathematical model solves conservation of charge, continuity equation, conservation of momentum, conservation of concentration, and conservation of energy. The results of numerical simulation are validated with available literature results. The effects of parameters such as inlet temperature, porosity, and pressure gradient on the cell performance were also investigated.

Keywords: PEM Fuel Cell, Modeling Fuel Cell, Numerical Model.

by G. A. Kahandagamage, N. S. Senanayake, T. S. S. Jatunarachchi

Vol. 7. n. 7, pp. 1446-1450

Abstract - This paper presents the results of a study carried out to determine the variations of Specific Fuel Consumption (SFC) and fuel efficiency in day time and night time operation of an intercooled direct injection diesel engine of 17MW used for electrical power generation. In the study pressure development curves for 18 cylinders were obtained and the Mean Indicated Pressure (MIP) and crank positions for the Peak Pressure, Kinetic Burning (KB), and Diffusive Burning (DB) points were analyzed. The results showed a reduction of 1.9% in SFC in the night time operation in which the charge air temperature was lower and relative humidity was higher than those of day time. The reasons for changes in SFC are explained with the changes in the in-cylinder pressure curves. Further, the fuel efficiency was found to be increased in the night time by 0.8%..

Keywords: Specific Fuel Consumption, Diesel Engines, Mean Indicated Pressure.

by M. Belcadi, , H. El Rhaleb, K. Gueraoui, , M. Driouich

Vol. 7. n. 7, pp. 1451-1484

Abstract - The engineering applications of technical ceramics are generally related to microstructure-controlled properties. The main objective of processing is to produce the desired microstructure, which frequently involves obtaining high density and small grain size. In the present study hybrid heating technique, which combine direct microwave heating with laser heat sources was proposed to sinter alumina which is a poor absorber of microwaves at room temperature. With increasing temperature by absorbing laser radiation, alumina can absorb microwave energy. The aim of this work is to explore numerically the hybridization of laser and microwaves energies to achieve rapid sintering with controlled grains size, density and free cracks sample by minimizing the temperature gradient between the core and sample surface. The simulation use finites volumes method in FORTRAN program.

Keywords: Sintering, Microwave, Laser, Alumina, Grain Size.

by V. Bristot, V. Bristot, O. Montedo, C. Rodriguez, D. Rocha, T. Piucco

Vol. 7. n. 7, pp. 1485-1463

Abstract - This study aims to develop an electromechanical system to perform alternating movements, including ascents and descents in a stacker machine for classification of ceramic tiles, replacing a cylinder hydropneumatic where this is showing faults during the working process. Initially, we collected some system parameters such as time of ascent and descent of the truck and the mass of the system by adding the mass of the material, in this case the ceramic coating. Given this information we propose design all efforts in the system and make the correct choice of machine elements to be used in the mechanism. This will be through mathematical calculations, brochures, catalogs, books, parts of machinery and the use of software like SolidWorks. The final set will consist of a geared traction as main axes (driving and driven), and synchronized belt pulleys, bearings, screws and mounting base. The proposed project aims to minimize downtime, reduce maintenance cost of repairing these cylinders, gain speed and thereby improve the performance of machine.

Keywords: Tools, Hydraulic Presses, Manufacturing Process.

by Muataz Hazza F. Al Hazza, Mohammed Baba Ndaliman, Muhammad H Hasan, Mohammad Yeakub Ali, Ahsan Ali Khan

Vol. 7. n. 7, pp. 1464-1470

Abstract - Electrical discharge machining (EDM) is a very complex and stochastic process. Thus, it is difﬁcult to predict or to estimate its output characteristics accurately by mathematical models. Therefore, the non-conventional techniques for modeling become more effective. In this research, the Artificial Neural Network (ANN) was applied as an effective tool for modeling and predicting the surface roughness (SR), Material Removal Rate (MRR) and Tool Wear Rate (TWR). The EDM performance of Cu compact electrode have been investigated with peak current (Ip), pulse duration (ton) and duty factor (η) as the input variables. A set of experimental data was obtained with different levels. The experiments were planned and implemented using Central Composites Design (CCD) of Response Surface Methodology (RSM) with three input factors at five levels. The neural network model was built by using MATLAB. The results indicate that even with the complexity of developing a model and predicting the results in EDM process, the neural network technique is found to be adequate in predicting the SR, MRR and TWR. Predictive neural network models are found to be capable to give high accuracy.

Keywords: EDM, Ti6Al4V Alloy, PM Copper Electrode, Surface Roughness, MRR, TWR, ANN.

by Ushasta Aich, Asish Bandyopadhyay, Simul Banerjee

Vol. 7. n. 7, pp. 1471-1494

Abstract - As technology advances, understanding the mechanism behind hybrid nontraditional processes is prerequisite for its effective commercial application. To enhance the versatility of Abrasive water jet machining (AWJM) process a comprehensive study of previous work is necessary. Researchers investigated the AWJM process from different point of view and concluded a number of remarks regarding the different aspect of the process. Widely scattered technical information are collated and explicitly presented in this paper. Findings from different works are broadly classified in modeling, parametric study and optimization. As one main benefit of using AWJM is that it is capable to machine almost all types of materials, so materials used for experimental works are also highlighted. A number of possible future scopes in this field of study are added in conclusion of this paper.

Keywords: AWJM Process, Modeling, Parametric Study, Optimization.

by M. Koilraj Gnanadason, P. SenthilKumar, Vincent H. Wilson, A. Kumaravel

Vol. 7. n. 7, pp. 1495-1506

Abstract - The water and the energy are the two most essential things for the sustaining of life. Freshwater is one of the Earth's most valuable renewable resources. Water has been recognized as a basic human right. The increasing world population and the rapid increase of industry and agriculture activities all over the world contribute to the depletion and pollution of fresh water resources. The available fresh water is finite on earth and its demand is increasing day by day. The utilization of renewable energy has a flourishing future and plays an important role in the domain of brackish and seawater desalination in developing countries. A solar still is a low-tech way of distilling water, powered by the heat from the sun. The problem of solar stills is the low productivity. In this context, two stills of basin made with copper sheet were fabricated and experimentally tested for Nazareth climatic condition (90N, 770E) for atmospheric pressure and vacuum conditions. In this study the comparative performance of single basin solar still working between at atmospheric pressure and with low pressure of 0.1 bar inside a still basin are compared. The vacuum still ensures higher rates of evaporation even at low temperatures and in turn increases the efficiency. This cost estimation was done to find the feasibility to provide the rural communities an efficient way to convert the brackish water in to potable water. The theoretical results also agree well with the experimental ones.

Keywords: Solar Still, Distillate, Vacuum Pump, Productivity and Still Efficiency.

by M. Gnanasekaran, A. Kumaravel

Vol. 7. n. 7, pp. 1507-1514

Abstract - The present study deals with the effect of activating flux and surface oxidation on micro structure, micro hardness and tensile strength of Tungsten Inert Gas welded 304 austenitic stainless steel plates. The thickness of the plate of 6.5 mm is considered for the investigation. The Tungsten Inert Gas welding is performed with 2.4mm diameter conical electrode tip profile with the surface condition of the plate as natural, oxidized and coated with an activating flux. Results have shown that the microstructure and mechanical properties are greatly influenced by activating flux and surface condition of plate. A-TIG welded plates give highest tensile strength when compared to TIG welded plates. Vickers micro hardness value is maximum nearer to the weld center on the cross section of the A-TIG butt weld joint.

Keywords: Activating Flux, A-TIG Welding, Surface Oxidation, 304 Stainless Steel.

by R. Vinayagamoorthy, Md.Aslam, K. Vamsi Krishna, M. Anthony Xavior

Vol. 7. n. 7, pp. 1515-1522

Abstract - This research work focuses on precision turning of Ti6Al4V material to investigate the machinability of the material. Precision turning is a type of machining where, very low feed rate and depth of cut is being used to machine using a cutting insert with a lower nose radius. The cutting parameters considered for the experiments include the cutting speed, feed rate, depth of cut and nose radius. PVD coated carbide cutting inserts with different nose radius and constant rake and clearance angle are being considered for experimentation. The experimentation was designed based on Taguchi’s L 27 orthogonal array. Three different levels of cutting parameters were being considered for the experimentation. The turning experiments were carried out on a conventional variable speed motor lathe under dry working conditions. Based upon the experimental values, Analysis of Variance (ANOVA) was conducted to understand the influence of various cutting parameters on cutting force, surface roughness and cutting tool temperatures during precision turning of titanium alloy. There are a number of techniques available for predicting responses using input parameters e.g. fuzzy inference system (FIS) etc. But present work uses Fuzzy Inference System (Mamdani Fuzzy logic) to predict the dimensional accuracy in part produced by precision turning.

Keywords: Titanium Alloys, Precision Machining, Cutting Tool Temperature, Surface Roughness, Cutting Force, ANOVA, Fuzzy Inference System .

by Sathiyamoorthy V., Sekar T.

Vol. 7. n. 7, pp. 1523-1528

Abstract - The first attempt is to introduce nano particles mixed electrolyte in electrochemical machining (ECM) process on improving material removal rate (MRR) and minimum surface roughness (SR) of high carbon high chromium die steel (HCHCr) with 67 HRc. The intervening variables (MRR and SR) depending upon the process parameters of ECM like applied voltage, tool feed rate, electrolyte concentration composition and electrolyte flow rate. In this experimental work two electrolytes, namely plain aqueous sodium nitrate (NaNO3) and 40 grams of copper (Cu) nano particle mixed with plain aqueous sodium nitrate electrolyte. The experimental results provide evidence that Cu nano particles mixed aqueous NaNO3 electrolyte improves MRR and minimum SR of HCHCr die steel on maximum working conditions when compared to plain aqueous NaNO3 electrolyte under similar working condition.

Keywords: Electrochemical Machining (ECM), Sodium Nitrate (NaNO3), Nano Copper particles (Cu), Material Removal Rate (MRR), Surface Roughness (SR), High Carbon High Chromium Die Steel (HCHCr).

by S. Balasubramanian, K. Manonmani

Vol. 7. n. 7, pp. 1529-1536

Abstract - This paper indicates the enhanced method of producing components of textile machines. The use of Nd-YAG laser beam in the manufacturing process improves quality of the components. The bottom rollers are one of the few important parts of textile machine giving quality yarns. The objective is to harden the complex shaped bottom roller and to eliminate post processes like grinding, bend removing followed by transportations and thereby made to run concentrically and giving quality yarn. The traditional processes of flame hardening, gas carburizing, nitriding, and induction hardening partially fulfil the requirements of hardness parameters on the roller. The laser hardening process was performed with 3 axes CNC machine attached with fiber optic laser head and servo controlled rotary chuck and suitable fixtures. The results of laser surface hardening show improved hardness, microstructure and uniform case depth on all contours and very less warping. The laser treated roller subjected to the normal working conditions on a textile machine run with almost concentric for longer life with which the yarn quality can be improved.

Keywords: Nd – YAG Laser, Surface Hardening, Textile Machines, Bottom Rollers, Contour Surface, Quenching, Warping, Fiber Optic, Uniform Case Depth, Concentric Rotation, Thick And Thin Places, Quality Yarn.