Product visualization, realization and reliability of non-hermetically encapsulated integrated circuit packages

Padmanabhan Krishnan

The aim of this investigation is to generate 3D models of eight different Thin Dual or Quad Leadless Moulded IC packages and conduct the performance analyses using die shear, thermal experiments and finite element analysis. Reliability plays a major role at every stage in the manufacturing, testing and use of integrated circuit packages. The coupled influence of operating voltages and joule heating on the mechanical reliability of ICs is discussed here. Die shear tests were conducted on the ICs and the shear strength compared with the values obtained from the finite element results. Thermal tests were carried out on the ICs that were later inspected under a Scanning Acoustic Microscope (SAM) for delaminations arising from hygrothermal stresses. Finally the results of the electro-hygrothermo-mechanical analyses were analyzed and presented at the maximum operating temperature (MOT) that highlight the overall static reliability of the ICs with acceptable factors of safety. The main objective of this investigation is the construction of the failure envelopes through determination of the maximum operating temperatures and test temperatures of the ICs that aid in the evaluation of the overall static reliability of the ICs.

Design for fatigue and simulation of glass fibre/epoxy composite automobile leaf spring

Amol Bhanage and K. Padmanabhan

In the present work, steel leaf spring used in passenger cars is replaced with a composite leaf spring made of a glass/epoxy composite The primary objective is to compare fatigue characteristics of SAE1045-450-QT steel and E - Glass/ Epoxy Composite material. Based on the available design data a fatigue analysis is carried out on an ANSYS Workbench v14.0 and the results of the simulation are documented. Factors like fatigue life, fatigue damage, biaxiality indication, rain flow counting and fatigue response are plotted for the composite leaf spring and the fatigue performance is predicted using life data. Therefore the objective of this paper is to present a design and simulation study on the fatigue performance of a glass fibre/epoxy composite leaf spring through design and finite element method and prove the reliability of the validation methods based only on simulation, thereby saving time, material and production costs for a complete product realization.

Analysis of dismantling processes for assessing disassembly effort and ergonomic hazards at the end of life of electronic appliances

Harivardhini S. and Amaresh Chakrabarti

The objectives of the research proposed in this paper are to: (i) review the state of art of various operations carried out during e-waste dismantling processes including dismantling equipment used and dismantling issues encountered in informal sector and formal sector, (ii) identify dismantling processes encountered during recycling and reuse of electronic appliances, and (iii) assess their associated disassembly effort and ergonomic hazards. The methodology adopted includes: data collection by interviewing dismantlers, video recording of dismantling processes, and identifying various dismantling issues and dismantling processes involved in recycling from the Literature and data analysis to assess disassembly effort and ergonomic hazards of the dismantling processes identified. Disassembly effort was measured in terms of Disassembly Effort Index (DEI) using a DEI model, and ergonomic hazards were assessed by an MSD Risk Assessment Checklist tool. Evaluation of DEI and ergonomic hazards was carried out on various electronic appliances that have reached their End of Life (EoL). Results of Evaluation are tabulated. Some of the most difficult disassembly steps and ergonomic risks associated with both formal and informal sectors were identified. It was found that there is a correlation between the number of disassembly steps and the Total DEI score. Also, the results on ergonomic risks found from the study showed that the ergonomic risks associated with informal sector are more serious than those in the formal sector. These include awkward postures, high hand forces and highly repetitive motions.

Optimization of machining parameter for turning of EN 16 steel using grey based Taguchi method

P. Madhava Reddy, P. Vijaya Bhaskara Reddy, Y. Ashok Kumar Reddy and N. Naresh

This paper presents the optimization of CNC turning parameters for EN 16 steel bar using the Grey Taguchi Method. A plan of experiments based on Taguchi’s L27 orthogonal array was established and turning experiments were conducted with prefixed cutting parameters for EN 16 steel bar using tungsten carbide tool. The turning parameters are cutting speed, feed rate and depth of cut and the responses are surface finish and material removal rate. Taguchi’s signal-to-noise (S/N) ratio are determined based on their performance characteristics. A grey relational grade is obtained by using S/N ratio. Based on grey relational grade value, optimum levels of parameters have been identified by using response Table and response graph and the significant contributions of controlling parameters are estimated using analysis of variances (ANOVA).

Life cycle assessment of thermal insulating building materials using building information modeling

K. Jagruthi, N. Ciddarth and M. Ramesh Kannan

Abstract:

This paper discusses the integrated whole-building process of achieving the most economic and energy efficient design of a common residential building through the sustainable design. This involves positioning and orientation of the building with respect to the annual sun path, adjusting the percentage of openings in the building, usage of the low energy impact materials in non-load bearing structures. Life cycle Analysis of the materials to be used in the non-load bearing members has been integrated in this analysis. Energy analysis of the materials to determine the lower impact on the environment is computed by the SimaPro software. The results thus obtained are used to analyze the heating and cooling demand graphs using CASAnova. The real time analysis and modeling of the typical building is computed by Autodesk® AutoCAD® 2014, Autodesk® Revit® 2013, and Autodesk® Ecotect® Analysis 2010 by trial and error method. All the dimensions are followed as prescribed in the National Building Code 2005-Part 8.

Markov based exploration for aircraft design time compression

Vasantharaju C., B. Ashok and C. D. Naiju

Abstract:

The design of Aircraft and especially the fighter Aircraft is increasingly getting complex. Added to the complexities of the design and need to integrate several disciplines, there is an added challenge of working with technologies that are still in drawing boards to be incorporated in future design. Needless to add, validation and testing of entire system / subsystem is a pain point.  Hence there is a clear need to design the aircraft in such a manner to accommodate for futuristic technologies and compress the design cycle times. On an average, design and development of a Military aircraft either for developed countries or developing countries requires a minimum of 13 years from the launch of project to the first flight. As the years get passed on new technologies and advancement also develops and it will become difficult to identify and incorporate to the ongoing projects.  A novel approach of using Markov process for achieving these objectives is explored. Markov based approach as a stochastic approach normally used to predict future states on the basis they have no link to the past is explored. A step by step approach by taking a typical design life cycle process of a particular component/assembly of aircraft is discussed. In this, design is split in to sequential stages, based on our prior design experience a probability is assigned to all foreseeable possibilities, and then that is converted to transition probability. Using a simple concept that any probability less than 1.0 leads to extended design life cycle, suitable cost and time factors.

Three dimensional visualization for fast display of vector fields using illuminated stream lines

Gunasekaran G. and Bimal Kumar Ray

A new technique for interactive vector field visualization using large numbers of properly illuminated stream lines is presented. Taking into account ambient, diffuse, and specular reflection terms as well as transparency, we employ a realistic shading model which significantly increases quality and realism of the resulting images. While many graphics workstation offer hardware support for illuminating surface. Primitives, usually no means for an accurate shading of line primitives are provided. However, we show that proper illumination of lines can be implemented by exploiting the texture mapping capabilities of modern graphics hardware. In this way high rendering performance with interactive frame rates can be achieved. We apply the technique to render large numbers of integral curves in a vector field. The impression of the resulting images can be further improved by making the curves partially transparent. We also describe methods for controlling the distribution of stream lines in space. These methods enable us to use illuminated stream lines within an interactive visualization environment.

Design of fuel tank baffles to reduce kinetic energy produced by fuel sloshing and to enhance the product life cycle

R. Thundil Karuppa Raj, T. Bageerathan and G. Edison

Abstract:

Fuel sloshing occurs in vehicle when it accelerates or decelerates. It generates high kinetic energy with unpleasant noise. This fuel sloshing leads to vehicle imbalance. This vehicle instability may occur when the fuel to weight ratio is high. In automobiles, the fuel sloshing generates unpleasant noise which is not expected from the present ones. So, this work presents the use of baffles at different positions in the fuel tank to suppress the fuel sloshing. Generally this phenomenon is seen in High Density Polyethylene (HDPE) tanks which are strong and light in weight. Introduction of baffles in the HDPE tanks is an onerous process through blow moulding. So the present work mainly focuses on the simulation of the slosh experiments to analyse the baffle design. The result depends upon the number of baffles, location of the baffle and its shape. The highest noise is generated only when the fuel hits the top of the tank. The baffle is designed in such a way that these noises are reduced. The height of the baffle should be sufficient enough to reduce the flow of fuel. The work mainly focuses over the selection of appropriate height of the baffle which gives optimum result with less effect on the fuel capacity of the tank. For this work, the fuel tank is modelled with Solidworks 2011. The fuel tank is meshed in ICEM CFD. It is solved in Ansys CFX 12.0. The Turbulent kinetic energy, force and velocity produced by the fuel during sloshing are calculated. The kinetic energy produced by the fuel produces the stress at the ends when reaching the ends of the tank. So the use of baffle reduced the noise and as well as the stress created at the ends. The product life cycle of the tank is also improved.

Influence of cutting parameters on dry machining of Inconel 625 alloy with coated carbide insert - A statistical approach

K. Venkatesan, R. Ramanujam, Vimal Saxena, Nilendukar Chawdhury and Vikash Choudhary

Abstract:

This paper investigates the influence of cutting parameters on machinability of a Ni-Cr alloy, Inconel 625, with coated carbide inserts (PVD AlTiN). In this work, a bar type Inconel 625 sample was chosen and based on Taguchi’s L9 orthogonal array, turning experiments were conducted at different levels of cutting speed, feed rate and depth of cut. The performance measures, cutting force and surface roughness, were measured to analyze the machining effectiveness. The signal-to-noise (S/N) ratio, the analysis of variance (ANOVA), and regression analysis were employed to find the optimal levels and to analyze the effect of the cutting parameters for the objective of lower cutting force and better surface finish under dry cutting conditions. The obtained results indicated that PVD coated inserts performed better in terms of cutting force and surface roughness with designed cutting parameters. The relationship between the independent variables and dependent variables is determined through a quadratic multiple regression model. From the statistical analysis, the results show that surface roughness is greatly influenced by feed rate and followed by cutting speed. The feed rate exhibits the maximum influence on cutting force components as compared to the depth of cut and cutting speed.

A CFD investigation on fluid dynamic gauging

R. Thundil Karupparaj, Bharani Kumar K.V. and M.P. Dhyan Shankar

Abstract:

This study deals with computational fluid dynamics (CFD) of fouling inside tubes or passages. These cases arise in present industrial situations involving fluid flows inside. The investigation on fouling is carried out by the technique called fluid dynamic gauging (FDG), which is a non-contact technique for measuring the thickness of soft deposit layer on solid surfaces immersed in liquid environment in situ and in real time. Laminar Newtonian flow has been investigated with Reynolds number at the nozzle throat in the range 116<Ret<930 and with the flow velocity of 0.0015 m/s to 0.124 m/s with water as the working fluid. The 3-dimensional model is created using SOLIDWORKS software. The fluid domain is discretized using finite volume method using ICEMCFD12.1 pre-processing tool. Both hexahedral and tetragonal mesh is generated which is used to capture the hydrodynamic boundary layers. The flow field through the 3-dimensional domain is captured by solving the appropriate governing equations namely conservation of mass and momentum equations. The convergence criteria are set to 10E-04 for mass and momentum. The numerically predicted results are compared with the experimental data available in the literature and a very good agreement exists between the two. Fouling phenomenon is calculated by finding the pressure difference between inlet and gauge tube outlet.

Empirical study on outsourcing factors for collaborative product development in aircraft programmes in India

G. Ramakrishnan and Prakash Sai

The objective of this paper is to investigate the impact of factors that contributes to the success of engineering and embedded systems outsourcing in complex product development and to develop an outsourcing framework for collaborative product development in aircraft programmes in India . Based on the review of literature on complex product development and strategic outsourcing, the potential factors that determine the product development outsourcing outcome have been identified. The factors are further validated through a qualitative analysis with the experts in the field with more than 20 years of experience. A survey instrument is developed for data collection to validate the model. An exploratory factor analysis has been done on the data collected during the pilot study phase. An important insight from this study is that the technical factors and process factors play a crucial role in determining the outsourcing outcome in the product development in aircraft industry. There is a significant variation in the outcomes depending on the discipline. The implementation factors are more relational in nature with respect to R and D labs / PSUs and are more contractual in nature when it comes to private industries. The study has limitations of looking into the product development outsourcing outcome of only one programme and from the client perspective alone.

New product development by DFMA and rapid prototyping

Wankhade Nitesh Prakash, V. G. Sridhar and K. Annamalai

In any manufacturing process, design is the first step where most of the important decisions are made which affects the final cost of the product. In this paper the researchers have used Design for manufacturing and assembly (DFMA) to re-design a fluid flow control valve and optimized its design to ensure the reduced number of parts, safety, reliability, time to market and customer satisfaction. In this research work the main emphasis was given to the design stage of a product development to obtain an optimum design solution for an existing product, DFMA concepts were used to produce alternative design ideas and the rapid prototyping process was used to develop a prototype for testing and validation of these alternative designs. Optimum design, low cost and good quality with quick delivery was the outcome of this research work.

Product lifecycle management (PLM) implementation for the airborne early warning and control (AEW and C) programme

Ashu Bhatia, Pradeep Raja, Sai Gunaranjan and Ananth Nath Talla

The Programme Office (PO), Centre for Airborne Systems (CABS), Defense Research and Development Organization (DRDO) is tasked with the development of the Airborne Early Warning and Control (AEW and C) System for the Indian Air Force (IAF). Being a large System-of-System Product, not only do the inherent product complexities through controlled and traceable product development environment pose numerous challenges but the requirement of spearheading and managing the co-operation between the Work-Centres (WCs) spread out across India is difficult.  At the very onset, the PO recognized the need to adopt and deploy a suite of State-of-the-Art Hardware and Software that would focus on leveraging the AEW and C Programme information to deliver the system within time, cost and quality envisaged. The paper brings out how the PO effectively faced the numerous challenges at both the Product and Programme level through use of the Product Lifecycle Management (PLM) Technology.

On the sustainability of the ancient Ratnagiri university complex: A design reconstruction study

S. Ghosh, R. Mathew, P. Gupta, A. Khanna and S. Saha

Ratnagiri University was an ancient residential Buddhist University that flourished during the period of 6th-12th century CE in Orissa (20.6330N 86.3330E). In this study we seek to examine the energy efficiency of the University’s edifices from a fluid mechanical point of view, using the Software Autodesk® Ecotect® and X-Flow. From a site visit, notable phenomena such as stack ventilation effects in the multi storied dormitories and acoustic filtering of high frequency sounds were suggested upon examining the building forms, which included stupas, courtyards, both windowless and windowed rooms and numerous sculptures amongst a large medley of archaeological remains. This study, the first ever to analyze an ancient Buddhist University , places a particular emphasis on the orientation, siting, infiltration, ventilation, day lighting and acoustics. From these analyses we seek to infer the prowess of the populace of that period, concerning harness of natural resources and design strategies.

Effect of sky scrapers on natural ventilation patterns and human comfort index in low-risebuildings - A CFD analysis over central Mumbai

J. Nagawkar, S. Ghosh, R. Kataria, A. Nashit and A. Deora

Mumbai, the financial capital of India and one of the world’s largest Mega Cities by the sea, is witnessing a massive construction boom. This can be attributed to the rapid economic growth as well as increase in population density. The number of skyscrapers has escalated to 140 (as of 2012), highest in any Indian city, with several more in the pipeline. It is also home to 1480 high-rise buildings. These towering, sharp-edged structures produce great amount of frictional drag and create turbulence in the boundary layer, significantly impacting the low-rise buildings lying in their wake. A CFD analysis to simulate air flow patterns around Tardeo (Latitude: 18°58’21.95” N, Longitude: 72°48’44.19” E) in Mumbai, has been conducted using ANSYS CFX to obtain pressure and velocity profiles- these product modeling simulations are expected to inform green architects engaged in sustainable design enhancements.

Investigations on the lubricated wear of direct metal laser sintered components for functional applications

C. D. Naiju, P. M. Anil, M. Mohan Prashanth and S. Karthik

Direct Metal Laser Sintering(DMLS) is a sequential layered manufacturing method to produce any desired three dimensional parts with simple or complex shapes with no or minimum post-processing. In this study Bronze-Nickel powder was used to make the samples.  The samples were produced with the optimized set of parameters such as sintering speed, scan spacing, hatch type, hatch distance and infiltration based on previous studies. To investigate the tribological behavior of the sintered components for functional applications, reciprocating wear tests under lubricated condition were carried out. A ball-on-flat configuration was chosen for the tests. Using Design of Experiments, Taguchi’s modified L9 orthogonal Table has been implemented to carry out the experiments. Hardness, load and temperature were the three parameters considered and three levels were chosen for each to create the orthogonal array. Wear tests were carried out with the set parameters and wear rates of the DMLS samples were found out. ANOVA statistical method was used to find the influence of major parameter and the contribution of each parameter on the wear rate of the samples. It has been found that the applied load, one of the selected test parameters had more influence on lubricated wear as compared to other parameters.

Numerical analysis of helically coiled heat exchanger using CFD technique

R. Thundil Karuppa Raj, Manoj Kumar S, Aby Mathew C. and T. Elango

In the present study, 3 dimensional numerical analysis of helically coiled tube is carried out using commercial CFD tool ANSYS CFX 12.1. It is very difficult and time consuming if these analyses could be carried out experimentally and hence in the present work, efforts are taken to optimize the helically coiled tube with respect to heat transfer and flow parameters for various coil pitch. Analysis of heat exchanger is done using conjugate heat transfer. The 3-dimensional flow through the helically coiled tube is considered which would overcome the anisotropic flow properties that would arise due to complex turbulence phenomenon and flow deviations. The flow field through the helically coiled tube is simulated by solving the appropriate governing equations: conservation of mass, momentum and energy. The turbulence is taken care by Shear Stress Transport (SST) k-έ model of closure. SST k-έ has a blending function which acts as standard k-έ in the main stream flow and as Standard k-ω near the boundary layer where the gradient is much steeper. The numerically predicted results are compared with the experimental data available in the literature and a very good agreement exists between the experimental and numerically predicted data.

Comparative study of monocoque and semi-monocoque flight vehicle structures under structural and thermo-structural loads

R Santhanam, P. C. Jain, Y Krishna and PSR Anjaneyulu

Analysis of monocoque and semi-monocoque cylindrical flight vehicle structures by using finite element method has been carried out. Shell elements are used for idealizing skin portions and end rings and beam elements are used for idealizing stiffeners. The behaviour of these structures is compared in terms of mass, deformation, stress and buckling under structural and thermo-structural loads to study the effect of number of longitudinal stiffeners. The study shows that semi-monocoque structures give higher factor of safety and buckling load factor when only structural loads (axial force and bending moment) are acting on them and the same structure give lesser factor of safety and buckling load factor when thermal loads (temperatures) and structural loads (axial force and bending moment) are acting on them in a combined manner. It is concluded that monocoque structures are best suitable under thermo-structural load environments.

Safety assessment of a light transport aircraft (LTA) in the event of uncontained rotor burst and propeller blade failure

Rashmi Hundekari and Abbani Rinku

Throughout the life cycle of an aircraft, it is likely that it may encounter an uncontained engine rotor or propeller blade failure due to probable malfunction or failure of single or multiple engine components, inadequate rotor and casing design, fatigue, material imperfections, assembly errors and foreign object ingestion. Uncontained engine rotor or propeller blade failure can lead to catastrophic failure if not addressed adequately during design. To ensure safety of the flight in the event of rotor burst or propeller blade failure federal aviation regulations has set forth compliance requirements (FAR sections 25.903, 25.905.d) which states that the airplane must be capable of successfully completing a flight during which likely structural damage occurs as a result of a propeller blade impact, uncontained fan blade impact, uncontained engine rotor failure or uncontained high energy rotating machinery failure. Aircraft manufactures has to comply with the safety requirements mentioned above. Hence it is required to assess the risk, take adequate design measures to minimize the risk and show compliance by analysis or test that the damage caused is minimal and aircraft is capable of completing safe flight in the event of uncontained rotor failure. This paper demonstrates the methodology to be followed for performing safety assessment of a typical light transport aircraft (LTA) in the event of an uncontained rotor burst and propeller blade failure. Assessment method presented in this paper is generic in nature and can be used to assess the safety of any class of transport aircraft.

Prediction of residual tensile strength of laminated composite plates after low velocity impact

V. Balasubramani and S. Rajendra Boopathy

Laminated composite materials are extensively used in aerospace and marine industries because of their advantageous ratio between high stiffness and low weight as well as high strength and low weight. However, in this application these composites are subjected to low-velocity impact due to birds, hail, and rain and from dropped tools used during manufacture or maintenance. Low velocity impact damage is often internal and invisible, but can minimize the residual strength. In this study, the residual tensile strength of three stacking sequences of Glass Fiber Reinforced Plastic (GFRP) composites is determined after low velocity impact experimentally using threshold energy. A model has been selected based on linear elastic fracture mechanics for predicting residual strength of impacted GFRP composites. Experimental results show the reliability of the model in the field of low velocity impact and its usefulness in determining the residual tensile strength. The correlation between the analytical and experimental results was found to be very good. The determination of residual strength in impacted laminates is very useful for predicting product-life cycle.

Variation of undrained shear strength of unsaturated porous media with temperature and suction

Anuchit Uchaipichat

At present, the thermo-hydro-mechanical coupling in unsaturated porous media is an interested subject since the environmental issues have been raised worldwide. Thus, this paper presents simulation results of effects of temperature and suction on undrained shear strength of unsaturated porous media, which is an important parameter in geotechnical design and analysis. The equation of undrained shear strength including thermal effect was used to estimate the results at various temperatures and matric suctions. Typically, the results show that the undrained shear strength decreases with increasing temperature for all values of matric suction. However, the undrained shear strength increases with increasing matric suction for all values of ambient temperature.

Performance evaluation of diversified SVM kernel functions for breast tumor early prognosis

Khondker Jahid Reza, Sabira Khatun, Mohd F. Jamlos, Md. Moslemuddin Fakir and Sheikh Shanawaz Mostafa

Ultra wide-band (UWB) microwave technology is a promising candidate to detect the early breast cancer. This paper aims to depict pattern recognition performance of support vector machine (SVM) for confocal UWB breast tumor imaging dataset. A novel feature extraction technique is also introduced in this paper for the signal classification perfectly and promptly. SVM classifier functions the comparative study between SVM kernel functions includes linear function, radial basis function, polynomial and multi layer perceptions are investigated and verified for pattern recognition performance with the help of receiver operating characteristic (ROC) graph and confusion matrix. The main motto of this paper is to identify the tumor in its smallest dimension from available works including their data using the proposed feature extraction. In total, thirteen different sizes of benign tumors are being considered where the smallest and largest tumor sizes utilized are 1mm and 9 mm, respectively.

Hygrothermal response of plant fiber reinforced composites

Christian Sunday Chukwuekezie, Christopher Chukwutoo Ihueze, Jamaliah Idris and Gaius Debi Eyu

The effect of soaking time and temperature response for coconut and raffia fibre reinforced composite on their mechanical properties have been studied. Tensile and compression test for treated and untreated were performed using a universal testing machine (Monsanto Tensometer). The conditioned samples in each case show better tensile and compressive strength compared to the untreated samples. Raffia fibre reinforced polyester showed a better mechanical and moisture absorption properties at various operating temperature in the study.

An overview of isolation improvement techniques in RF switch

M. H. Abdul Hadi, B. H. Ahmad, Peng Wen Wong and N. A. Shairi

In this paper, five techniques to improve isolation of RF switch are reviewed which are material with fabrication process design, circuit design, resonant circuit, transmission line and resonator. Most of these isolation improvement techniques are applied in RF switch designs such as single pole single throw (SPST) and single pole multi throw (SPMT). Several solid-state devices are used for switching element such as PIN diode, MEMS, FET, HBT and HEMT. They are commonly used in satelite communication, radar system, instrumentation and base station applications.

Simulation and evaluation of performance parameters for PWM based interleaved boost converter for fuel cell applications

M. Tamilarasi and R. Seyezhai

In the present scenario, renewable energy sources are playing an important role to satisfy the requirements of customer’s demand. Among these sources, fuel cell is an attractive technology as it provides a clean and efficient source of electricity. But a suitable power conditioner is required to convert the DC power of fuel into useful AC power. This paper focuses on a four-phase directly coupled Interleaved Boost Converter (IBC) as a suitable interface for fuel cell applications based on pulse width modulation technique. The proposed converter is simulated in MATLAB/SIMULINK. Input current, inductor current and output voltage ripple is studied. Various energy factors have been computed and the results are verified.

Diagnosis of stator fault in asynchronous machine using soft computing methods

K. Vinoth Kumar, S. Suresh Kumar, A. Immanuel Selvakumar and Vicky Jose

Stator Winding Fault can be detected by monitoring any abnormality of the Park’s spectrum. In this paper is presented a fault-detection performance comparison between the Support Vector Machine (SVM) and backpropagation algorithm (BP) using experimental data for a healthy and faulty case. Support Vector Machine and Backpropagation Algorithm provide environments to develop fault-detection schemes because of their multi-input- processing and its good generalization capability. The training patterns are obtained using motor current signature analysis (MCSA) and using Spectral Park’s Vector. The neural networks are evaluated by means of the cross- validation technique to determine easily the diagnosis and severity of turn-to- turn faults.

Soret and Hall Effect on MHD flow, heat and mass transfer over a vertical stretching sheet in a porous medium due to heat generation

Mohammad Ali and Mohammad Shah Alam

The present study is considered by the   effect of Soret and Hall current due to heat generation on coupled heat and mass transfer by megnetohydrodynamic (MHD) free convection over a permeable vertical stretching sheet. The governing boundary layer equations are formulated and transformed into a set of similarity equations using dimensionless similarity variables. The governing fundamental set of a system of non-linear locally similar ordinary differential equations are solved numerically by Runge-Kutta fourth-fifth order integration scheme along with shooting technique. Numerical results for dimensionless velocity, Temperature and concentration profiles displayed graphically for pertinent parameters to show interesting aspects of the solutions. Also the skin friction coefficient, the rate of heat transfer and rate of concentration are presented in Table 1.

Study on the low temperature operability improvement of the heat pump dryer using a solar collector and an air collector

I. S. Hwang and Y. L. Lee

When drying frozen materials using a heat pump dryer, frost is formed on the evaporator, resulting in the liquid flood back of the compressor. Therefore, in this paper, a numerical analysis was conducted of a heat pump dryer with attached solar collector and air collector in order to enhance the low temperature performance of the heat pump dryer. According to the analysis results, when the solar collector was used in the given conditions, the low temperature performance was improved through the increase of evaporating pressure by approximately 61 kPa. Also, the COP increased by a maximum of 1.5 compared to the standard cycle. Meanwhile, when using the air collector, the evaporating pressure increased by 209 kPa and the COP increased by a maximum of 5.5 over the standard cycle. Thus, it is found the air collector is more effective than the solar collector in the considered conditions.

Medium of instruction (L1 versus L2): Which is Which in engineering education?

Victor Dagala Medugu and Amirmudin Bin Udin

The main purpose of the study was to establish the effects of National language (L1) as supplement to English Language (L2) in teaching and learning Motor Vehicle Mechanics (MVM) Trade as a pre- requisite course for Automobile engineering training in Technical Colleges. This was because of the massive failures of students in the said subject compared to other related engineering courses. Four specific objectives were stated to guide the study. Four corresponding research questions and two hypotheses respectively were stated based on the objectives and were tested at 0.05 level of significance. The design of the study was Quasi experimental (None equivalent) design covering all Technical Colleges in the State that offers Motor Vehicle Mechanics (MVM) Trade. There was no sampling technique used. Twenty multiple choice objective questions were administered by the researcher and the research assistant after face and content validation. Test- Retest method was used to determine the reliability of the items. Data collected were analysed using mean, standard Deviation and t-test. The results showed that the students taught (MVM) Trade using L1 as supplement performed significantly better and had positive attitudes towards MVM trade than those taught using L2.

Nano-electromechanical systems (NEMS) sensors are recently used as powerful medical detectors for detection of disease. In this research paper, the modified couple stress non-classic continuum theory is applied to examine the size effect on the pull-in instability of beam-type NEMS sensor at submicron separations considering the van der Waals attraction. The proposed model takes the non-classic support conditions into account using rotational springs at supported end of the simply supported nano-beam. In order to solve the nonlinear constitutive equation of the nano-beams, finite difference numerical solution employed. The results reveal significant influence of the size dependency, elastic support conditions and van der Waals attraction on the pull-in characteristics of beam-type NEMS.