bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of RC Type Electrical Discharge Machining on ASSAB 618 Steel Using Copper Electrode
Authors: Zaki Muhammad Zulhisham Ahmed , Azuddin M.
Published: April 2013

This paper presents the investigation on Electrical Discharge Machining (EDM) on ASSAB 618 steel using copper electrode. The sparking power was generated using Resistor Capacitor (RC) Circuit and not usual Transistor Pulse Generator Circuit. The performance of the electrodes in the EDM RC circuit was evaluated based on the achieved surface roughness with respect to material removal rate (MRR) and electrode wear ratio (EWR). In this study, investigations have been conducted with surface finish at different discharge energy output. It was found that the surface characteristics are dependent mostly on the discharge energy during machining. The fine finish electrical discharge machining requires minimization of the discharge energy supplied into the gap. In addition, the surface finish was found to be influenced greatly by the electrical and thermal properties of the electrode material.
Application of Size Optimization on Steel Wheel Rim
Authors: Ahmad Mohd Nizam , Muhamad Wan Mansor Wan
Published: April 2013

Structural optimization was important nowadays in getting the optimum design and usage of the material use, where size optimization is part of it. This research is focusing on the application of size optimization on steel wheel rim. Existing steel wheel rim dimension was measured and Finite Element Analysis (FEA) was done to get actual dimension and mechanical properties (stresses), as baseline data. CAD modelling on steel wheel rim was done using Pro-Engineer/Creo 1.0. One structural element was selected to be optimized. Then optimization program was generated using MAPLE to get optimum value (size). Steel wheel rim will be re-modelled with optimum size to get optimum design. FEA was done again on optimized steel wheel rim to compare with actual steel wheel rim data. Optimized steel wheel rim was showing better in mechanical stress with optimum size (minimize the weight and volume).
Educational Software for Stress Analysis of Idealized Thin Walled Open Sections
Authors: Mohamed Ali Jaffar S. , Fadhila Hasna Nur , Aziz Nor Azhanadia Binti
Published: April 2013

An educational software which can aid students in stress analysis of idealized thin-walled open sections has been developed. The software enables students to select different cross-sections which may be subjected to bending, shear or torsional loads and evaluate the stresses on it. Results obtained through this software have been validated. The software has been developed using MATLAB with graphical user interface (GUI). The software is expected to be a useful tool for effective teaching learning process of courses on thin-walled structures and aircraft structures.
Technology Transfer at Malaysia: Pharmaceutical Manufacturing Industry
Authors: Yap Bryan Kweh King , Heng Low Hock
Published: April 2013

Transfer of technology is the key element for the industrialization and economic development of the countries. Indeed, today, the transfer of manufacturing technology has become an important part of the international business strategy of firms. According to Schmidt and Uydess [1] pharmaceutical manufacturers are transferring more technology now compared to the last decade. Recent survey conducted by Tunnell Consulting, looking at the technology transfer practices of executives at 10 global pharmaceutical companies, the study found that most of companies undertake more than 10 technology transfer per year whether from development to commercial manufacturing or from one manufacturing site to another. The aims of the research is to identify the factor that will influence the technology transfer process in pharmaceutical manufacturing industry and provide the better understanding for pharmaceutical process validation at Malaysia. Respondents for this research included Manager, Engineer, Technician, Machine Operator and Supportive Staff at pharmaceutical manufacturing industry. This paper is considered as in progress status. Therefore it will explore and explain the concept of technology transfer and the factors that will influence the process.
Load Behavior Prediction in a Tumbling Mill
Authors: Akhondizadeh M. , Fooladi Mahani M. , Rezaeizadeh M. , Mansouri S.H.
Published: April 2013

mportance of the SAG (Semi Autogenous Grinding) mills for the mineral complexes persuades many researchers to study the behavior of these huge equipments. Laboratory mills and the DEM (Discrete element method) software are the prevalent and reliable methods of modeling the mill behaviors. The former is very costly and the latter not only takes the much time but also needs the very advanced computers. In the present work, a method is presented to predict the charge profile and shoulder and toe positions for a case study mill. Experimental relations are manipulated to determine the en masse geometry and the kinetic relations are used to explain the ball movement on the liner in order to determine the shoulder and toe positions. Model results have very good accordance with the experimental results obtained of a laboratory mill. The model is used to predict the load behavior of a SAG mill in the Sarcheshmeh copper complex in Iran. Acceptable results due to low cost and quickness make it as an appropriate method for predicting the charge profile in that tumbling mill.
Computational Analysis of Frontal Area of a Front Grill Passenger Car
Authors: Hakimi Hamid Muhamad Khairul , Mutasim Muhammad Ammar Nik , Idris M.S.
Published: April 2013

Designing the front grill with the focus on analyzing the flow from outside to the inside of a passenger car bonnet is very important in the automotive industry. This study was done to increase performance of the flow through the analysis on the effect of aerodynamic flow through the front grill by designing different cases of frontal areas of the front grill. Velocity at 34 m/s at steady condition were done to obtain the flow structure around a passenger car as well as the front grill of a passenger car. Analysis was taken inside the wind tunnel as the boundary condition. The grid generation was based on the tetrahedral unstructured meshes. Result obtain was compared with past experiment data. It was found that an appropriate design of frontal area of front grill can improved the stability of a car and the heat surrounding inside the car bonnet. Finally, the aerodynamics of the most suitable design of front grill was introduced and analyzed.
Effects of Cutting Condition on Surface Roughness when Turning Untreated and Sb-Treated Al-11%Si Alloys Using PVD Coated Tools
Authors: Barzani Mohsen Marani , Noordin Mohd Yusof , Farid Ali Akhavan , Farahany Saaed , Davoudinejad Ali
Published: April 2013

Surface roughness is an important output in different manufacturing processes. Its characteristic affects directly the performance of mechanical components and the fabrication cost. In this current work, an experimental investigation was conducted to determine the effects of various cutting speeds and feed rates on surface roughness in turning the untreated and Sb-treated Al-11%Si alloys. Experimental trials carried out using PVD TIN coated inserts. Experiments accomplished under oblique dry cutting when three different cutting speeds have been used at 70, 130 and 250 m/min with feed rates of 0.05, 0.1 and 0.15 mm/rev, whereas depth of cut kept constant at 0.05 mm. The results showed that Sb-treated Al-11%Si alloys have poor surface roughness in comparison to untreated Al-11%Si alloy. The surface roughness values reduce with cutting speed increment from 70 m/min to 250 m/min. Also, the surface finish deteriorated with increase in feed rate from 0.5 mm/rev to 0.15 mm/rev.
Hydrogen as an Alternative: Life Cycle Cost Analysis between Hydrogen Internal Combustion Engine (Al+Hci) and Gasoline Engine Based on Brake Specific Fuel Consumption
Authors: Razali Halim , Sopian Kamaruzzaman , Mat Ali Sohif
Published: April 2013

Estimation of the life cycle cost (LCC) for a hydrogen internal combustion engine (H2ICE) that uses hydrogen as an alternative fuel by forecasting a financial investment plan for a period of five years (n = 5). This is influenced by the interest rate of 10% (i = 10). The effect of Annual Operating Cost and salvage value in the LCC for H2ICE would give impact on the cost of investment and economic growth in the long term. The result shows the brake specific fuel consumption to achieve 14% savings for grams per kilowatt hour for the engine (G + H2) compared to the engine (G). The operation of H2ICE in the first year would be increased by 22%, the reason is due to the cost of equipment, maintenance and purchase of new components. However, the percentage of operation cost for the following five to ten year of Present worth (PW) is reduced to 0.36% in the fourth year (n = 4) within the interest rate of 10%. The return of initial investment in the capital-first cost (FC) is to occur at the beginning of the fifth year (n = 5) of H2ICE operations. The cost of savings for the next five years would become more profitable reaching 37% reduction in cost compared to conventional fuel consumption
Finite Element Modelling of Polymeric Foam-Filled Aluminium 2024-T4 Alloy Tube under Dynamic Axial Loading
Authors: Jailani Azrol , Othman Akhbar , Tajuddin Siti Mariam
Published: April 2013

The paper presents the numerical studies of two different tubes under axial impact loading structures. The cylindrical tubes filled with closed-cell polymeric foam. The deformation and failure mechanism of this new structure were observed and analyzed numerically using the finite element method. It is revealed that the stress distribution and fracture of the foam-filled tube structure are different from those of foam-filled tube. In comparison with double cell foam-filled tubes, the load-carrying capacity of this new structure is much steadier, the collapse behavior resistance is enhanced, and the weight efficiency of energy absorption is higher. Parameters affecting the performance of the foam-filled tube structures are also studied. Comparison were carried out with load versus displacement curve and also dynamic mean load as well as dynamic absorbed energy versus deformation of tubular collapse modeling failure mode using finite element analysis.
Heat Transfer Modeling of Metal Deposition Employing Welding Heat Source
Authors: Fawad Hasan
Published: April 2013

Gas Metal Arc welding (GMAW) has shown potential, for Layered Manufacturing (LM) of metallic components, due to its inherent feature of high inter-layer and metallurgical bonding. Residual Stress induced warping is a major concern in a variety of LM processes, particularly those seeking to build parts directly without post processing steps. The temperature distribution and re-melting depth plays an important role in controlling residual stresses and distortion. This paper presents a 3D finite element based thermal model of a novel welding based deposition process as applied to LM. The model showed good agreement with experimental data. The results show that the process is not axis symmetric and a complete 3D model is required for accurate prediction of temperatures and deformation.
Total Productive Maintenance: Competing or Complementary to other Initiatives?
Authors: Bakri Adnan Hj. , Rahim Abdul Rahman Abdul , Yusof Noordin Mohd
Published: April 2013

The objective of this short review paper is to examine the practical applications of Total Productive Maintenance (TPM) in the manufacturing industry. In this short review, an attempt was made to critically discuss the previous literatures related to TPM with the other established quality initiatives in the manufacturing, such as Total Quality Management (TQM) and Just-In-Time practice (JIT). This literature review-based research revealed an important research gaps related to TPM. The significance role of TPM as an important complementary to either TQM or JIT initiative is observed not been well addressed in the available literatures. Most of the researches available investigate these initiatives separately, focuses on the other element rather than addressing on the significant role of TPM as one of the main thrust. The separate implementation of such quality initiatives in the manufacturing organization means the requirement of large scale human, financial and technical resources as well the associated problems of running competing project in the company. The outcomes from this review justify the needs of further research in the area of TPM integration with other available initiatives, to further enhance its methodology aimed at solidifying its philosophy towards more realistic practical applications.
Effects of Intake Temperature and Equivalence Ratio on HCCI Ignition Timing and Emissions of a 2-Stroke Engine
Authors: Najafabadi Mohammad Izadi , Aziz Nuraini Abdul , Adam Nor Mariah , Leman Abdul Mutalib
Published: April 2013

Homogeneous charge compression ignition (HCCI) combustion, when applied to a gasoline engine, offers the potential for a noticeable improvement in fuel economy and dramatic reductions in NOx emissions. In this study, Computational Fluid Dynamic (CFD) is used coupled with detailed chemical mechanism (38 species and 69 reactions) for simulation of HCCI combustion of iso-octane and transitional flow inside the combustion chamber of a 2-stroke engine. Results show that increasing the overall gas temperature significantly advances the HCCI combustion timing. Concerning the equivalence ratio, by increasing it the ignition timing has been advanced and the maximum cylinder pressure has been increased. When equivalence ratio increases to more than 0.5 , NOx emissions significantly increases and go beyond 1000 [ppm].
Numerical Prediction of Heat Transfer from Localized Heating in Enclosure Using CIP Method
Authors: Sheldareh Ali Akbari , Safdari Arman , Sidik Nor Azwadi Che
Published: April 2013

In this paper, two-dimensional laminar natural-convection heat transfer of air has been numerically solved by Cubic Interpolated Method known as CIP which is based on the Eulerian mesh grid generation. For this investigation a cavity has been selected as a geometry which is being heated from bottom of the cavity at three different positions, the sides of the cavity are cold and the top of the cavity is adiabatic and no heat exchange exist there. The cavity is being heated from three different position of the bottom which is equal in length and equal but in three different position of left, center and right in equally distance. The whole simulation takes place in two various Grasshof number and air has been taken as fluid inside cavity. Prantl number has been set to 0.7 throughout the simulation. Results are presented in the form of streamlines and isothermal plots inside the cavity. The results illustrate the heat for middle heated plate is distributed symmetrically through the cavity.
Turbulence Kinetic Energy Performance on Wind Turbine Blade Using CFD
Authors: Sadikin Azmahani , Shamsudin M.R. , Wahab A.
Published: April 2013

Wind represents the kinetic energy of the atmosphere. Wind energy is currently supplying as much as 1% of the world electricity used, and could supply as much as 20% of global electricity in power and can be created through the use of wind turbines. Wind turbine blade is the most promising technology for the production of energy by using wind energy. Good design of wind turbine blade depends on performance of increasing to generate electricity which related with drag coefficient , lift coefficient and turbulence kinetic energy. However, the efficiency of wind turbine blade could be predicted by simulation due to flow streamline on wind turbine blade. This paper discuss the result obtain from simulation in CFD using CFX on NACA 4412 and NACA 4415.
Numerical Prediction of Heat Transfer from Heated Thin Plate in a Square Cavity by Using LBM
Authors: Kermani E.P. , Safdari Arman , Azwadi C.S. Nor
Published: April 2013

In this paper, natural convection heat transfer from heated plate positioned in square cavity vertically and horizontally was studied. Thermal BGK lattice Boltzmann numerical scheme was applied. The simulation was launched for different aspect ratio A=0.4 and 0.6 at Grasshof numbers and . Air was chosen as working fluid (Pr=0.71). Good arrangement was obtained between the present work and pervious approach using finite volume method. It is found that convection upper side of plate is increase as Grasshof number is increased.
Investigation on Sand Particle Impingement on Steel Pipe in Two Phase Flow Using Acoustic Emission Technology
Authors: El-Alej Mohamed , Mba David , Yan Ting Hu , Husin Shuib
Published: April 2013

This paper presents an experimental investigation that employed the acoustic emission (AE) technology to monitor sand transportation in two-phase flow. This investigation was undertaken on two phase (air-sand) flow in a horizontal pipe for varying Superficial Gas Velocities (VSG). The objective of this research programme is to develop a simple, non-invasive technique for monitoring of sand particle concentration levels in multi-phase flow conditions. The experimental findings show that AE absolute energy can be correlated with the size of sand, number of sand particles and Superficial Gas Velocity (VSG).
Investigating the Capability of Acoustic Emission Technology to Determine Slug Velocity in Gas/Water Two Phase Flow in Horizontal Pipes
Authors: Alssayh M.A. , Husin Shuib , Addali A. , Mba David
Published: April 2013

Two phase flow is a common phenomenon that exists in the petroleum and chemical engineering industrial fields. An important feature employed to describe two phase flow is the flow regime which varies depending on the individual velocities of the components within the two-phase flow. One of these regimes, the slug regime, can create significant pressure fluctuations that compromise the integrity of the transporting structure (pipes, separators, etc). This is in addition to other unwanted effects such as flooding at the receiving end, an increase in deposits of hydrates and corrosion. Under such circumstances the detection of the slug and its associated characteristics are vitally important to the operator. This experimental study looks into the application of Acoustic Emission (AE) technology for detecting slug velocity in two phase (gas/liquid) flow. It is verified that slug velocity can be determined by using acoustic emission sensors.
Optimum Combustion Chamber Geometry for a Compression Ignition Engine Retrofitted to Run Using Compressed Natural Gas (CNG)
Authors: Osman Shahrul Azmir , Alimin Ahmad Jais , Liong V.S.
Published: April 2013

The use of natural gas as an alternative fuels are motivated from the impact in deteriorating quality of air and the energy shortage from petroleum products. Through retrofitting, CI engine runs on CNG, will be able to reduce the negative impact mainly on the use of petroleum products. However, this required the modification of the combustion chamber geometry by reducing the compression ratio to value that suits combustion of CNG. In this present studies, four different shapes and geometries of combustion chamber were designed and simulate using CFD package powered by Ansys workbench, where k-ε turbulence model was used to predict the flow in the combustion chamber. The results of turbulence kinetic energy, velocity vectors and streamline are presented. The enhancement of air-fuel mixing inside the engine cylinder can be observed, where the design with re-entrance and lower center projection provide better results compared to other combustion geometries designs.
Modeling River Stream Flow Using Support Vector Machine
Authors: Rafidah Ali , Suhaila Yacob
Published: April 2013

Support Vector Machine (SVM) is a new tool from Artificial Intelligence (AI) field has been successfully applied for a wide variety of problem especially in river stream flow forecasting. In this paper, SVM is proposed for river stream flow forecasting. To assess the effectiveness SVM, we used monthly mean river stream flow record data from Pahang River at Lubok Paku, Pahang. The performance of the SVM model is compared with the statistical Autoregressive Integrated Moving Average (ARIMA) and the result showed that the SVM model performs better than the ARIMA models to forecast river stream flow Pahang River.
Hand-Arm Vibration Analysis of Palm Oil Fruit Harvester Machine
Authors: Md Salleh Salihatun , Rahim Erween Abdul , Ghazali Imran H. , Azmi Khairull , Jelani Abdul Razak , Ismail Mohd Fauzi , Ahmad Mohd Rizal
Published: April 2013

The objective of this study is to determine the vibration value of Palm Oil Harvester Machine or CANTAS motorized cutter profile. The CANTAS machines have been divided into twelve nodes and hand arm vibration measurements are taken for idle and full throttle operation. Three cutting heads provided by MPOB have been measured for comparison purposes. The hand-arm vibration values for Type A Cutting head achieves (3.89±1.10) m/s2 for idle condition and (10.71±2.88) m/s2 for full throttle condition. Meanwhile Type B Cutting Head achieves (3.63±0.87) m/s2 for idle condition and (11.22±1.74) m/s2 for full throttle condition. Type C of Cutting Head yields (3.51±0.82) m/s2 for idle condition and (15.54±3.81) m/s2 for full throttle condition along the structure. The results also shows which points depicted highest vibration level during idle (no operation, ideally from tree to tree) and full throttle (overuse operation). These values present the maximum and minimum vibration levels that will be received by the user in daily usage of the machine. design in reducing vibration to the hand-arm of the user.
Mercerization Treatment Conditions Effects on Kenaf Fiber Bundles Mean Diameter Variability
Authors: Hashim Mohd Yussni , Ahmad Norazlina , Roslan Mohd Nazrul , Ariffin Saparudin
Published: April 2013

The interest in utilizing natural fiber as reinforce in polymer composites has increased in recent years due to their advantages like availability, cheap, renewable, lightweight, and biodegradable. However, the main challenge of natural fiber to be used as reinforcement in polymer is their hydrophobic nature. One of the solutions is via chemical modification like mercerization treatment. In this study, the effect of alkali concentrations at 2 and 10 w/v %; and soaking temperature at 30°C and 80°C on a kenaf fiber bundles mean diameter was investigated. Untreated kenaf fiber was used as a control unit. Kenaf fiber diameter was measured using a Leica video analyzer. Microstructure change of kenaf fiber before and after mercerization treatment conditions was identified using JOEL scanning electron microscopy (SEM). Finally, an interaction of alkali treatment conditions on kenaf fiber bundles mean diameter value was statistically analyzed using a commercially available statistical software package. The results showed that kenaf fiber bundle mean diameter was reduced by 30.12% to 42.92% after mercerization treatment. From analysis of variance, the main effect of alkali concentration value was 6.075 and the temperature value was 1.135. The main effect plots reveal that alkali concentration had a higher impact on mean diameter changes compared to soaking temperature factor.
Fabrication of TiB2-TiC Composites Optimized by Different Amount of Carbon in the Initial Ti-B-C Powder Mixture
Authors: Zavareh Mitra Akhtari , Bin Abdul Shukor Mohd Hamdi , Ghahnavyeh Reza Rahbari , Roudan Malihah Amiri , Shafieirad Mohsen
Published: April 2013

Composites of TiC and TiB2 (TiC-TiB2) were prepared by self-propagating high-temperature synthesis (SHS), using compacted reactant different combinations of Ti, C, and B powders. It is very difficult to densify these materials using conventional sintering techniques. It was found that the chemical reaction between the starting Titanium, boron and carbon particles could be completed at 1200°C producing a pure TiB2+TiC ceramic composite. Various carbon content causes the microstructure of the final products was different.
Characterization of Chalawa River Sand for Foundry Application
Authors: Tijjani Y. , Onyekpe B. , Rafukka I.A.
Published: April 2013

The characterization of Chalawa river sand with its suitability for foundry applications has been investigated. Chemical and sieve analyses and Green permeability were determined for the sand via standard procedure. Based on the result of the chemical and sieve analyses and permeability (the sand by its high silica content and low alkali fluxes) it needs small amount of binder, has moderate refractoriness and therefore, can be employed in foundry applications.
Effects of End Mill Helix Angle on Accuracy for Machining Thin-Rib Aerospace Component
Authors: Izamshah Raja , Yuhazri M.Yaakob , Hadzley Mohd , Ali Mohd Amran , Subramonian Sivarao
Published: April 2013

Accuracy of machined component is one of the challenging tasks for manufacturer. In the aerospace industry, machining process is widely used for fabrication of unitized-monolithic component that contains a thin-walled structure. During machining, the cutting forces cause deflection to the thin-wall section, leading to dimensional form errors that cause the finished part to be out of specification or failure. Most of the existing research for machining thin-wall component only concentrated on the process planning and the effects of cutter geometric feature is often neglected. Tool geometric feature has a direct influence on the cutting performance and should not be neglected in the machining consideration. This paper reports on the effect of helix angle on the magnitude of wall deflection. The established effects will be used for the development of high performance cutting tool for specifically machining thin-wall component.
Combustion Characteristics of Compressed Natural Gas in a Direct Microchannel-Injection Engine under Various Operating Conditions
Authors: Mohamad Taib Iskandar , Geok How Heoy
Published: April 2013

The combustion characteristics of compressed natural gas (CNG) in a direct microchannel-injection engine under various operating conditions were investigated. In this study, a novel idea for direct CNG microchannel injection was realized with spark plug fuel injector (SPFI). It is a device developed to convert engine to CNG direct injection (DI) operation with minimal cost and technical simplicity. It was installed and tested on a Ricardo E6 single cylinder engine with compression ratio of 10.5:1 without modification on the original engine structure. The engine test was carried out under various operation conditions at 1100 rpm. Burning rates of CNG were measured using normalized combustion pressure method by which the normalized pressure rise due to combustion is equivalent to the mass fraction burned (MFB) at the specific crank angle. The results showed that the MFB of CNG direct injection is substantially faster but initially slower than the ones of port injection. The optimal fuel injection and ignition timings are 190 °CA ATDC and 25 °CA BTDC respectively. The optimal injection pressure was 6 MPa. Combustion durations were not changed with different injection pressures but ignition delay was affected. There was no direct correlation between injection pressure and ignition delay which is most probably due to the effect of charge flow difference. Changing mixture stoichiometry affects the magnitude of ignition delay. Combustion duration, on the other hand increases with leaner mixture.
Evaluation of Sustainability Performance of Product Design Element Concepts Using Analytic Hierarchy Process
Authors: Hassan Mohd Fahrul , Saman Muhamad Zameri Mat , Sharif Safian , Omar Badrul
Published: April 2013

ntegrating sustainable product design into the design process has been acknowledged nowadays by many companies for producing sustainable products. The integration should be implemented during the early stage of product development process so that the sustainability of the product can be evaluated before manufacturing the product. Although a number of studies have been conducted on the integration in many aspects along with many approaches, evaluation of the sustainability of the product during its total life-cycle while it is being designed has not been comprehensively investigated. In this paper, Analytic Hierarchy Process (AHP) is used to evaluate product design element concept during conceptual design stage by providing a weightage of sustainability metrics throughout the total life-cycle of product and finalize the preferred product design configuration by selecting the highest sustainability index of the design element concept. The approach is useful for product designers to design many concepts of product design elements and then to select the most likely sustainable design element to configure in one complete product. An example of an armed chair is used to demonstrate this approach.
Load Capacity of Partially Textured Journal Bearing with Trapezoidal Recess
Authors: Rao T.V.V.L.N. , Abdul-Rani Ahmad Majdi , Thirumalaiswamy Nagarajan , Hashim Fakhruldin M.
Published: April 2013

This work presents the load carrying capacity of partially textured journal bearing with trapezoidal recess. The partial texture geometry is composed of a number of successive cells of trapezoidal recess and land configurations. The non-dimensional pressure expressions for the partially textured journal bearing with trapezoidal recess are derived. Results of nondimensional load capacity are provided taking into consideration of texture geometry with trapezoidal recess and extent of partial texture.
An Investigation of the Scope for Improvement of the Performance of Multi-Stage Downdraught Evaporative Coolers Using CFD
Authors: Sarjito Sarjito
Published: April 2013

Downdraft evaporative cooling systems can be used for the thermal management of inside spaces in hot dry environments. There may be scope for improvement of such systems. The work described here is a study aimed at validating the Computational Fluids Dynamics (CFD) method using experimental data available from a prototype multi-stage system which existed at Ben-Gurion University. A detailed model of the prototype device has been developed. Initial CFD work has focused on establishing the relationship between ambient wind speed and the downdraft flow rate and comparing the result with the existing experimental data. Initial results are consistent and encouraging. Detailed flow features not evident from the experiments are revealed. Further CFD work to model the prototype performance with water spray evaporation is described briefly.
Creep Analysis of Functionally Graded Material Thick-Walled Cylinder
Authors: Jamian Saifulnizan , Sato Hisashi , Tsukamoto Hideaki , Watanabe Yoshimi
Published: April 2013

In this paper, creep analysis for a thick-walled cylinder made of functionally graded materials (FGMs) subjected to thermal and internal pressure is carried out. The structure is replaced by a system of discrete rectangular cross-section ring elements interconnected along circumferential nodal circles. The property of FGM is assumed to be continuous function of volume fraction of material composition. The creep behavior of the structures is obtained by the use of an incremental approach. The obtained results show that the property of FGM significantly influences the stress distribution along the radial direction of the thick-walled cylinder as a function of time.
Energy Absorption Characteristics of Polyurethane Composite Foam-Filled Tubes Subjected to Quasi-Static Axial Loading
Authors: Subramaniyan S. Kanna , Mahzan Shahruddin , Ghazali Mohd Imran , Zaidi Ahmad Mujahid Ahmad , Prabagaran Prasath Kesavan
Published: April 2013

Foam-filled enclosures are very common in structural crashworthiness to increase energy absorption. However, very less research has been targeted on potential use of natural/recycled material reinforced foam-filled tubes. Therefore, an experimental investigation was performed to quantify energy absorption capacity of polyurethane (PU) composite foam-filled circular steel tubes under quasi-static axial loading. The thickness of the tubes was varied from 1.9, 2.9 and 3.6 mm. The tubes were filled with PU composite foam. The PU composite foam was processed with addition of kenaf plant fiber and recycled rubber particles that were refined at 80 mesh particulates into PU system. The density of PU resin was varied from 100, 200 and 300 kgm-3. The PU composite foam-filled tubes were crushed axially at constant speed in a universal testing machine and their energy absorption was characterized from the resulting load-deflection data. Results indicate that PU composite foam-filled tubes exhibited better energy absorption capacity than those PU foam-filled tubes and its respective empty tubes. Interaction effect between the tube and the foam and incorporation of filler into PU system led to an increase in mean crushing load compared to that of the unfilled PU foam or tube itself. Relatively, progressively collapse modes were observed for all tested tubes. Findings suggested that composite foam-filled tubes could be used as crashworthy member.
Optimizing Assembly Sequence Time Using Particle Swarm Optimization (PSO)
Authors: Mukred Jameel A.A. , Muslim Mohd Taufiq , Selamat Hazlina
Published: April 2013

Assembly sequence planning (ASP) plays an important role in the production planning and should be optimized to minimize production time and cost when large numbers of parts and sub-assemblies are involved in the assembly process. Although the ASP problem has been tackled via a variety of optimization techniques, these techniques are often inefficient when applied to larger-scale problems. In this study, an approach using particle swarm optimization (PSO) is proposed to tackle one of the ASP problems which are optimizing the assembly sequence time. PSO uses a number of agents (particles) that constitute a swarm moving around in the search space looking for the best solution. Each bird, called particle, learns from its own best position and the globally best position. Experimental results show that PSO algorithm can produce good results in optimizing the assembly time, has a powerful global searching ability and fast rate of convergence.
Strategies for Integrating Quality, Environmental, Safety and Health Management Systems
Authors: Mohammad Musli , Osman Mohd Rasid , Mohd Yusuff Rosnah , Masood Ibrahim , Yahya Mohd Shahir , Azlis-Sani Jalil
Published: April 2013

This paper discusses the strategies for integrating Quality, Environmental, Safety and Health Management Systems based on survey and case studies results. Questionnaires were distributed to 87 companies that certified with both ISO9001 and ISO14001. Meanwhile, three case studies were conducted at the manufacturing companies that have integrated several management systems. There are two ways of integrating the management systems which are: (1) consecutive implementation of management systems followed by integration or (2) integrate the management systems simultaneously from the beginning. Based on survey and case studies, it was found that many organisations started with implementing individual management system first, and then followed by integrating the management systems. Almost all the survey respondents agreed that the sequence should start with establishing Quality Management System first, and then integrate with Environmental Management System and followed by Occupational Health and Safety Management System.
An Exploration to Develop Concrete Walls Using MnxZn1-xFe2O4 Ferrite as Absorbing Material to Provide Defense against Electromagnetic Pollution
Authors: Yee See Khee , Kiong Sia Chee , Mohd Zarar bin Mohd Jenu
Published: April 2013

Concern regarding the shielding effectiveness (SE) of building materials is gaining more response nowadays due to the awareness on the electromagnetic pollution (EMP) that is believed to results in disastrous consequence. A pure concrete inherently providing certain level of SE but it is not enough. Hence additional shielding and absorbing additives are added into the concrete. In this work MnxZn1-xFe2O4will be added into the pure concrete to enhance its SE performance. The effect of microstructure, compositions, grain sizes, homogeneity, mixture volume of the MnxZn1-xFe2O4will be considered for the optimization in this mixture. The key component to determine the SE of concrete is their electrical characteristic (relative permittivity and relative permeability). The parallel plate which is proposed previously will be used to determine the electrical characteristic of material and it will also be used for SE measurement.
Boundary Conditions and Constraint Equations for Simulation of Energy Exchange
Authors: Poruba Zdenek , Szweda Jan , Podešva Jiří
Published: April 2013

The contribution and presented work deals with the CFD simulation of heating and air conditioning process of a special vehicle. The aim of the work is then the capacity validation of the heat exchanger which provides the heating or cooling of the air supplying the vehicle. Because of the high dimensionality and complexity of the whole task, the number of simplifications in the form of proper boundary conditions and constraint equations was proposed by authors. The presented paper contains the presentation and discussion of the used simplifications, the saved computational capacities are accented and results in the form of distribution of thermomechanical quantities are presented. Finally, the capacity of heat exchanger used is validated.
Towards Biomimetic Actuation in Prostheses Using Shape Memory Alloy
Authors: Low Cheng Yee , Kasim M. Amlie A. , Jaafar Roseleena , Jaffar Ahmed
Published: April 2013

Shape Memory Alloy (SMA) has been identified as an ideal candidate to actuate the finger joints of hand prosthesis due to its silent operation, small size, high force to weight ratio and operational similarity with human muscles. When current is applied to a SMA wire, the material is heated up. A phase transformation from Martensite to Austenite takes place and the wire contracts. This work evaluates the displacement and force produced from the contraction of a type of SMA wire, i.e. Nitinol (Ni-Ti). The displacement is determined by a linear potentiometer while the force is determined by a load cell. Furthermore the impacts of varying the bias force exerted on the SMA wire and the input current passed through the wire are investigated. Such insight into the characteristics of SMA can be used to realize biomimetic actuation in order to improve the dexterity of hand prosthesis.
Analysis of Unimorph Piezoceramic Patches on Damped Square Shaped Plate
Authors: Najib A.M. , Fairul A.J. , Bani Hashim Ahmad Yusairi , Hasib Hazman , Muhammad M.N.
Published: April 2013

Active damping using piezoelectric element is one of the effective techniques to counter vibration problems. A 3D finite-element model is developed as part of investigation for damping control. The piezoelectric patches are surface bonded on quadrilateral thin plate and supported with spring damper elements. The main goal of this paper is to investigate mechanical characteristics of piezoceramic array on membrane and the effect of force excitation using small motor and electric excitation on the system. The system setup produced small vibration displacement and does not displace the plate beyond elastic strain region. The results show the linear behavior of piezoceramic and the correlation between electric excitation, motor vibration and displacement at the centre of the plate at different frequency range. The mode shapes and natural frequencies at low frequency spectrum are also presented. Therefore, the results can be used as reference to develop damping system with aid of piezoelectric patches.
The Effect of Pretreatment Powder Using Ball Mill and Ultrasound on the Properties of Single Cell Solid Oxide Fuel Cell
Authors: Sulistyo S. , Ariffin Saparudin , Mahzan Shahruddin
Published: April 2013

Solid oxide fuel cell (SOFC) is currently popular due to its capability to convert hydrogen into electricity directly from oxidizing hydrogen fuel. The SOFC is one of the expected renewable energy devices and green technology in the future because of less carbon dioxide production and no pollutant product. Performance of SOFC was influenced by morphology and microstructure of the material, starting particle size and particles distribution. This paper addresses the comparative evaluation of using pretreatment NiO/YSZ powder using ball mill and ultrasound processess on the performance of a single cell SOFC. The performance of solid oxide fuel cell was evaluated using scanning electron microscopy (SEM), X-Ray diffraction (XRD) and impedance spectroscopy, measured at room temperature. The results indicate that the treatment using ultrasound process is better than ball mill process due the total resistance is smaller and distribution particle is more homogenous.
Surface Energy and Crystallite Size Comparisons by Applying Direct Current and Pulse Direct Current on Substrate Bias in PVD Process
Authors: Hanizam H. , Abd Rahman Md Nizam , Mohamad Noraiham , Soufhwee A.R.
Published: April 2013

Surface morphology homogeneity and energy modifications for in situ PVD process are two critical factors to prevent unexpected adhesion failure during machining or service. Unlike during film depositing, there is still much gap to be explored on applying pulsed biasing concepts to the substrate during in situ, to ensure the substrate surface readiness prior to film coating. The purpose of this paper is to study the effects of conventional direct current (DC) and pulse direct current (PDC) applied at substrate bias to the surface energy and crystallite size. Tungsten carbide (WC) cutting tool insert and titanium nitride (TiN) were used as substrate and hard coating respectively. The runs were conducted to compare the bias at DC (-500V) and PDC (-200V, -500V, -800V). The surface energy and crystallite size were characterized through wettability test and X-ray diffraction (XRD) analysis. The applying of PDC on the substrate bias was found to further enhance the characteristics of the surface compared to the conventional DC substrate bias.
Study of the Influence of Normal and High Blood Pressure on Normal and Stenosed Carotid Bifurcation Using Fluid-Structure Interaction
Authors: Abdul Khader S.M. , Ayachit Anurag , Pai Raghuvir , Zubair M. , Ahmed K.A. , Rao V.R.
Published: April 2013

Atherosclerosis (stenosis) is a common cardiovascular disease in which the blood vessel restructures by narrowing, thickening and gets hardened due to the deposition of plaque. A detailed study of narrowing of arteries applying computational aspects which leads to better findings in order to know the underlying mechanics of development and progression of such diseases. Such kind of analysis can be a useful tool for the medical professionals to study the realistic physiological conditions. They can simulate and observe the blood flow in arteries. In the present study, a case of normal and stenosed carotid bifurcation is simulated. The models are generated in CATIA based on the clinical data obtained from a patient using Ultrasound Doppler. A transient FSI analysis considering Newtonian behavior is performed to compare the significance of High Blood Pressure (HBP) and Normal Blood Pressure (NBP) on carotid bifurcation. The FSI simulation is carried out for both HBP and NBP conditions for several pulse cycles on normal and stenosed models using ANSYS13.0 to demonstrate the changes in flow behavior at various sections of the model. The computed results agree well with clinical observations and available literature as seen in case of NBP.
Experimental and Simulation Validation Methods of Local Exhaust Ventilation (LEV) in Training Facilities Building
Authors: Seng Ng Chee , Leman Abdul Mutalib , Sadikin Azmahani
Published: April 2013

LEV is a ventilation system that collects and sucks out particles such as dusts, mists, gases, vapors or fumes out of work station, so that they can’t be breathed in by occupants. There is a lot of LEV allocated and installed in order to help protecting occupants’ health but it doesn’t work properly. To overcome this issue, computational fluid dynamics (CFD) will be implemented. Past studies CFD techniques represent a very significant improvement of air ventilation systems. However, CFD is just a tool in prediction model, which can lead to inaccuracy of predicting airflow due to problems with pre-processing, solver and post-processing with parameter from actual experimental results. As of yet, it is not possible to 100% accurately simulate airflow around a body. These codes are simply models which are close to that of a real flow, but not an exact match. All of these require validation to help minimizing percentage error in CFD methodology. Several strategies are needed to boost effectiveness of LEV in terms of predicting airflow in a geometry model. The outcome of this research can be used as a benchmark or guideline for industries to help improving indoor air quality (IAQ).
Synthesis and Characterization of Nano Particles of Mn-Co Ferrites for Technological Applications
Authors: Anis-ur-Rehman M. , Zeb-un-Nisa Mughal , Ansari Mariam , Maqsood Asghari
Published: April 2013

Manganese doped cobalt nano ferrites were synthesized by co-precipitation method having general formula Co1-xMnxFe2O4 (x =0.0-1.0). These materials are studied to analyze the structural effects on the associated materials properties. The prepared samples were heat treated at 7500 C for two hours. Sintering effect on the structural properties was investigated. The lattice constants of samples were measured from X-rays diffraction data. The (311) peak was used to find crystallites size by the Scherrer formula. Structural morphology was observed by scanning electron microscopy. Variation with temperature in electrical resistivity (DC) and drift mobility were also investigated. The variations with frequency and composition in AC electrical properties of prepared samples were determined. The structural and electrical properties demonstrated firm association. Saturation magnetization, coercivity and remanence of the samples were discussed with the help of sharing of cations within crystals.
Thermal Expansion and Polarization Behavior in Lead Titanate/Zinc Oxide Nanocomposite Ceramics
Authors: Wongmaneerung Rewadee , Ngamjarurojana Athipong , Yimnirun Rattikorn , Ananta Supon
Published: April 2013

Nanosized zinc oxide/lead titanate (ZnO/PT) ceramic matrix nanocomposites have been studied. Under an appropriate sintering condition, ZnO/PT ceramic nanocomposites were successfully fabricated by a pressureless sintering technique. Thermal expansion and polatization behaviors were determined by using the dilatometer. This technique measures the temperature-dependent of the strain, and the magnitude of polarization can be deduced from the sets of the thermal expansion data. The calculated electric polarization values on the ZnO/PT nanocomposite ceramics show the simple approach to determine the temperature dependence of the polarization below and around the transition temperature. Various aspects on understanding the polarization behavior and other effects in the ferroelectric are discussed.
The High DC Electric Field Effects on the Dielectric Behavior of Barium Strontium Titanate Ceramics
Authors: Zhang Qi Wei , Zhai Ji Wei , Yao Xi
Published: April 2013

BaxSr1-xTiO3 (x=0.4, 0.5, 0.6) ceramics were fabricated by the conventional solid-state reactions method. The temperature dependences of the dielectric constant and tunability were investigated under high DC electric field. It was found that the change of dielectric constant and tunability under the applied electric field were closely related to ferroelectric phase, phase transition region and paraelectric phase states. The Curie temperature (Tc) was gradually shifted to higher temperature and were broadened and depressed with increasing of DC electric field. The tunability dependence of temperature exhibits different trends in a wide temperature range and reaches a maximum value near the ferroelectric-paraelectric phase transition. These results may be helpful in understanding the mechanism of dielectric response under higher electric field.