Design of composite fixture for machining ceramic materials using abrasive water jet machining (AWJM)

S. Renold Elsen, T. Ramesh, M. Thirumalai kumar and A. Aslam Khan

The conventional machining of ceramic components is a hard task because of its brittle nature. Water jet machining is one among the non-conventional machining processes which is suitable for machining of ceramics. In this work, a fixture is developed to cut ceramics rods each of diameter varying from 9 to 7 mm and 30 mm length into two pieces. The fixture was developed to reduce the machining time, to hold the ceramic rods safely after machining and to eliminate the abrasion on the machine work Table while cutting rods. The proposed design has to adhere less fabrication cost without compromising the strength of the fixture. Since the clamping device requires numerous machining operations for holding 22 pieces of varying diameter, it was proposed to select wooden material as the clamping device. Mild steel rod was selected to support the clamping device. Finite element simulation was carried out to simulate the force acting on the fixture during machining. Further, the ceramic rods were machined in the water jet machine using the fabricated fixture. The machining cost is reduced to approximately Rs 1000 per hour.

Reduction of greenhouse gas emission during product life cycle by removing CO₂ in boiler industry using mathematical modeling and simulation

J. G. K. Kumar and L. R. Ganapathy Subramanian

Carbon Dioxide is one of the important and major Green House Gas, It is mandatory to be removed after any combustion process (from the flue gases). In this Research work the removal rate of Carbon Dioxide (CO₂) in the flue gases coming from the combustion process of Boiler would be removed. There are common processes are available for the removal/ Separation of Carbon dioxide, but it takes more amount of energy. By comparing with this formerly the combustion process with the pure oxygen can be done for removal of carbon dioxide. With this the redesign of boiler is required and secondary option is chemical solvents (like monoethanolamine, diethanolamine and methyl diethanolamine etc.) process can be adopted and modified in the boiler system. The later one gives the significant reduction of electricity bills. By utilizing the different Special chemical solvents in the vertical column, the Mathematical model will be introduced to compare the rate of removal, further it is simulated using MATLAB and chemCAD software and by comparing the simulation results one of the best Special solvent is selected for greater energy efficiency and lowering the electricity costs.

Modeling, simulation and analysis of a SCARA robot for deburring of circular components

P. V. S. Subhashini, N. V. S. Raju and G. Venkata Rao

Selective Compliance Assembly Robot Arm (SCARA) is an arm configuration obtained by the combination of articulated and cylindrical arm configurations. SCARA is widely utilized for various industrial applications where accuracy and precision are essential. In this paper, an analysis of SCARA robot as applied for deburring parts having circular profile and the deburring operation is fixed to a time period of 6 seconds is carried out. A complete mathematical model is carried out for kinematics and equations are derived using Denavit-Hartenberg notation. SCARA robot in the present case is modeled using CAD software and motion simulation is carried out. Different kinematic parameters include joint angles, positions, and velocities are calculated from CAD software and compared with the results obtained from MATLAB. It is observed that all the results match fairly closely. The reasons for deviations may be that while MATLAB solves the equations directly through symbolic language code, where as analysis by the other codes and software are carried out through numerical schemes.

Modeling of two-echelon inventory system under exponential price dependent demand

Burra Karuna Kumar, D. Nagaraju, S. Narayanan and K. Syam Sundar

In the present day scenario of globalization, the concept of supply chain management (SCM) has gained significance as one of the 21^st century manufacturing paradigms for improving organizational competitiveness. In this context, a two level supply chain model is developed considering a single manufacturer and single retailer. The main objective of this research is to demonstrate the optimality of the decision variables and objective function for respective entities as well as for the entire chain under exponential price dependent demand. The mathematical model is developed in two fold. First, the expression for the total variable cost of the retailer and manufacturer is developed independently and then for the entire supply chain as a function of ordering/set up costs and carrying costs. Numerical example is devised and the computer program is written in MATLAB. The model is solved for optimality of inventory level, number of shipments and the total relevant cost of the individual entities and the entire chain for coordinated and non coordinated supply chain. Also, the sensitivity analysis is carried out. From the research findings, it is evident that with supply chain coordination, the total relevant cost of supply chain decreases.

Design, development and validation of fire protection scheme for the engine firewalls and cowling of a typical light transport aircraft

H. T. Akshatha, A. Rinku and R. Gopalakrishnan

Abstract:

In an aircraft, engine firewalls refer to the structural components which isolate engine hot section and accessories section from plenum chamber and cowling refer to the outer skin of nacelle. As per the federal aviation regulation (FAR) requirement, the firewalls should be “fire proof” and the engine cowling should be “fire resistant”. This can be achieved by selecting proper material and suitable surface protection. The present work deals with design and development of a fire protection external coating scheme for a light transport aircraft (LTA) fire wall and cowling, its validation through acceptance tests and simulation (using FE software) of stiffness variation of structure due to variation of temperature-thus estimating the residual strength and integrity of structure.

Evolutionary optimization of geometric tolerances for compliant assemblies with contact interactions

Arunachalam Saravanan, C. Balamurugan and A. Karthik

Abstract:

Geometric Dimensioning and Tolerancing (GD and T) is an important activity during product development phase, since it directly influences the Manufacturing cost and subsequent manufacturing time. Traditional GD and T design methodology assumes the complete assembly is perfectly rigid; hence it often leads to costly reworks and rejections. This increases the product development time and cost, also it forces the entire assembly to accommodate major Engineering Changes (EC) in order meet the product functionality. This paper proposes an ideal alternative methodology to overcome the effects of the assumptions. Initially contact interactions in the assembly are simulated by Finite Element Analysis (FEA), since the mechanical contact influences severe nonlinearities, which makes the assembly compliant and non-ideal. The simulated compliant assembly is modeled using three dimensional degrees of freedom approach and an optimization problem is framed with an objective function of minimizing the manufacturing cost. Assembly function constraints, Machining constraints and tolerance zone constraints are considered to solve the problem using Genetic Algorithm (GA). Finally an industrial example is chosen to illustrate the highly structured methodology.

Hardware in loop simulation and performance measures of a two wheeler using virtual vehicle simulator

Mugunthan G., Balasubramanian E., Madhavan R. and Jebin Singh J.

This paper discuss in detail about the performance measures such as suspension effectiveness, brake effectiveness, and wheel wobbling of two wheelers without human intervention. The Vehicle performance simulator has been designed in a solid modeling package which cater multi variant of vehicles through adjustable wheel base, modular clamping and load system, and also by servo based cam/drum roller.  Simulation studies were performed by controlled force application to front and rear suspension there by measuring the suspension and damping effectiveness of the vehicle. The drum roller was used to accelerate front and rear wheel to the desired speed and by applying brake at specific load, break effectiveness has been measured. The wobbling of the wheel was obtained with the aid of laser sensor embedded on the simulator. The proposed work aims at replacing the human efforts to improve the quality and productivity in the automobile sectors. In this work a virtual prototype vehicle simulator is presented to eliminate the error on the various performance measures of the two wheeler vehicle which helps in increasing the product life cycle management.

Effect of ribs and stringer spacings on the weight of aircraft composite structures

Arunkumar K. N. and Lohith N.

Abstract:

Low cost and less weight are the two primary objectives of any Aircraft structure. Efficient design of Aircraft components is therefore required to reduce cost and weight. For components with compressive loading, ribs and stringer spacing and stringer cross-section play a major role for weight efficient design. The main objective of the present work is aimed at establishing optimum stringer and rib spacing and stringer cross-section for minimum weight of buckling design driven components using FEA. The problem is formulated with flat ‘skin-stringer’ and ‘skin-stringer-rib’ panels with different stringer cross sections viz. blade, hat, I and J. Parametric studies are executed with different stringer spacings, rib spacings and stringer cross sections to study the effect of these parameters on the weight of the structure using Composite (T800class+epoxy system) material through linear buckling analysis of the FE model. Simply supported boundary conditions are used on all four edges of the plate with compressive loading. The software tools used are Hypermesh as pre and post processor and Radioss as solver. Initially for all the stringer cross sections considered, stringer spacing is varied from 600mm to 50mm. It is found that the spacing below 120mm is stabilizing the weight. Too small a spacing will increase the number of stringers with issues in fabrication without much benefit in terms of weight. With this view point, two stringer spacing configurations viz. 150mm and 120mm are considered for further study on the rib spacing for each of the stringer cross sections stated earlier. Optimum stringer spacing, rib spacing and stringer cross sections are established quantitatively.

Product detailing, a key to implementation of product design concepts for sustainable design

Nitin Khedkar, Vinay M. Mundada and Kushal Jadhav

Abstract:

Design detailing plays very important role in implementing the concept. In the research work proposed the efforts are made to evolve a systematic approach to consider the various detailing aspect in the concept stage itself. The main aspects of detailing are Surface details, Functional details, Structural details, Construction details, Aesthetics details, Manufacturability details and Ergonomics details. Surface details include the texture, color, blending of different parts, etc. The functional details include the fits, movements, thicknesses, internal components, etc. Structural details include the materials, their properties, parts, etc. The construction details include modularity and stability. The aesthetic details include all the things which are externally visible to the user which also includes the form.  Manufacturing details include costs estimation of manufacturing, components, assembly, production support and environmental impact. Ergonomic details include human factors for the intended use.

Performance evaluation of coated carbide inserts on dry machining of Al-B₄C metal matrix composites using Taguchi’s robust design and weighted grey analysis

Abstract:

This paper presents the fabrication and machinability assessment of aluminum metal matrix composites (Al-MMC). Boron carbide (B₄C) particles having average size of 37 µm is dispersed in 6061-T6 matrix alloy. The composite bar was fabricated through mechanical assisted stir casting method. Machining experiments based on Taguchi’s L9 orthogonal array was conducted under dry condition using multi-layer coated carbide insert (TiN/Al₂0₃/TiCN/TiN). Machinability indices such as surface roughness (R_a, R_t and R_z) and cutting force (F_z) were considered as response measures. The results obtained from experiments were analyzed to predict the optimal machining conditions using Taguchi single objective approach. From the statistical analysis it was found that the feed rate is the most influencing factor for both surface roughness and cutting force followed by depth of cut. The developed mathematical model shows that the experimental and predicated results are very close to each other. Finally, the single optimal process parameter combination was found using weighted grey analysis (WGA) and the optimal results are verified through confirmation experiment.

Implementation of genetic algorithm to optimize the assembly sequence plan based on penalty function

Arun Tom Mathew and C. S. P. Rao

Genetic Algorithms (GA) are, conceptually, suitable to optimize the Assembly Sequence Planning (ASP) problem. GA was implemented in this research to optimise the ASP problem because they can easily handle large search spaces, flexibility in defining the constraints and derive them in a fitness function. A penalty function approach has been used to compute the fitness value for assembly sequences. The penalty function approach was chosen as the penalties are easy to define, realistically capture the difficulties associated with the assembly process and the number of penalties to consider is relatively reduced. The evaluation of the penalty function is simple and straightforward, a most desirable feature for a population-based search.

Multi-Response optimization using ANOVA and desirability function analysis: A case study in end milling of Inconel alloy

R. Ramanujam, Lohithaksha M. Maiyar, K. Venkatesan and Mithun Vasan

Nickel-based super alloys are classified as ‘difficult to machine’ materials due to its inherent characteristics such as high hardness, and toughness, high strength at elevated temperatures, low thermal conductivity, ability to react with cutting inserts, and ability to weld onto the surface of the cutting insert. The present study investigated the parameter optimization of end milling operation for Inconel 718 super alloy with multi-response criteria based on the taguchi method and desirability function analysis. Experimental tests were carried out based on an L9 orthogonal array of Taguchi method. The influence of machining factors cutting speed, feed rate and depth of cut were analyzed on the performances of surface roughness and material removal rate. The optimum cutting conditions are obtained by Taguchi method and desirability function. The analysis of variance (ANOVA) is also applied to investigate the effect of influential parameters. A regression model was developed for surface roughness and material removal rate as a function of cutting velocity, feed rate and depth of cut. Finally, the confirmation experiment was conducted for the optimal machining parameters, and the betterment has been proved.

Design and development of stamping dies for online maintenance

Jai hindus S.

This paper assists the die designer to design press tool dies for the online maintenance in the press itself and to reduce the tool failure due to the dynamic actions of the press tool in the press. In the proposed die design the parts such as punch, punch holder, stripper, die and the die inserts can be removed in the press itself without disturbing the die set. The route chart of the die (tool) maintenance can be decreased by implementing the methodology. The proposed approach increases the productivity by adopting more feasibility to attend online maintenance, and reduce the overall productivity hours.

Examination of the Lattice Boltzmann method in simulation of manufacturing

This work is concerned with the characteristics of incompressible viscous flow inside a two-sided lid-driven cavity with its two opposite walls moving with a constant velocity in parallel direction and in antiparallel direction by Lattice Boltzmann method (LBM). The model used in the present work is two-dimensional nine-velocity (D2Q9) square lattice as it gives more stable and accurate result when compared to two-dimensional seven-velocity (D2Q7) hexagonal lattice. The characteristics of flow problem are investigated for different Reynolds number and also for aspect ratio, K = 2.0 and 5.0. The formation of different vortices with the variation of Reynolds number for parallel and antiparallel motion is studied in detail. To sum up, the present study reveals many interesting features of two-sided lid-driven deep cavity flows and demonstrates the capability of the Lattice Boltzmann method to capture these features.

In a shop floor, minimization of makespan (Total Completion Time) has been an interesting area for many researchers for over six decades. The problem for the process planning engineer is to find a processing order of the ‘n’ jobs, the same for each machine, such that the make span is minimized, that is, the ‘n’ jobs are finished as soon as possible. In this paper, one attempt has been made to develop and use one ‘Random Simulation Algorithm’, with the objective of improving the makespan. Benchmark problems proposed by Taillard are used here for the validation purpose. These values have been compared with the makespans obtained from the original NEH algorithm and the ‘NEF family’ of algorithms proposed by the authors. For the 120 number of problem instances analyzed, the new algorithm reports better makespans, than the original NEH algorithm, in 114 cases. The ANOVA indicates that, the Random Simulation Algorithm performs slightly better.

Optimization of mechanical behaviors of bio particulates filled Coir-Polyester composites using simulated annealing

G. Bharathiraja, S. Jayabal, R. Prithivirajan and S. Sathiyamurthy

The mechanical behaviors of Coir-Polyester composites are greatly improved by the impregnation of bio particulates. The present investigation is focused on the evaluation and optimization of mechanical behaviors of Coir-Polyester composites filled with bio particulates such as red mud and termite mound soil. The composite fabrications were planned as per Design of Experiments with fabrication parameters like fiber length (mm) and particulate content (%). The tensile, flexural and impact strength of fabricated composites were evaluated as per ASTM standards. The effect of fiber length and particulate content on the mechanical behaviors of Coir-Polyester composites was studied using ANOVA and Response Surface plots. The nonlinear regression models were developed for the prediction of mechanical behaviors over the specified range of conditions. The fabrication parameters for the optimum value of mechanical behaviors were determined using the single solution metaheuristic algorithm called Simulated Annealing.

Assessment of form tolerances by least square method

Gopinath L., Ravishankar S. and Nagarajan S.

Form tolerances are related to features that are not dependent on datum for reference, where the overall feature accomplishes form. Evaluation of form tolerance is done from the sample space data set, its distribution and measurement factors.  Average value of deviation to assess the tolerance may give a quick picture of variation but shall not contribute to the characteristics of slope/fluctuations in the readings. The knowledge of the expected geometry achieved by best fit computation through any of the mathematical procedure provides the primary iterative step to define manufacturing variation. This paper discusses the best fit by Least Square Method by analyzing the data and deviations considered for the form tolerances such as Flatness, Circularity and Straightness. The standard mathematical definition for the validation of the form tolerances are drawn from the ASME Y14.5M standards. The case studies to evaluate the mathematical method are carried out for flatness on the surface plates, Circularity on Ring gauges and Straightness on a straight edge. The deviations of the points from the Gaussian geometry are compared against hard inspection methods and the reliability of the best fit by least square method is discussed against the BIS standards and its characteristics by a normal distribution curve.

Computerized maintenance management system for indigenously developed fighter aircraft inline with emerging trends

Sanjay Kumar Shukla, Satish Kumar, P. Selvaraj and V. Subba Rao

The ground and flight tests play a crucial role during proto-vehicle development for any fighter aircraft development program. The objectives of the prototype testing are to assess the aircraft's mission capability in a phased manner. The observations from the field trials are of immense value. In addition to the aircraft performance assessment, the data from field trials facilitate in assessing the Reliability and Maintainability (R and M) of various aircraft components at system level and optimize the maintenance procedures to reduce Turn around Time (TAT). The fleet of proto-vehicles meant for field trials undergoes frequent change in Standard of Preparation (SOP), leading to update of maintenance procedures. This poses a great challenge for the planning of aircraft maintenance activities. This paper brings out a conceptual model of Computerized Aircraft Maintenance Management System (CAMMS), which is relevant to the typical military aircraft flight testing and servicing activities during prototyping and certification phase. An enterprise-wide CAMMS based on Product Lifecycle Management (PLM) would act as a digital thread between designers, maintenance planners, flight test engineers, inspectors and certification agency. CAMMS would enable to track various Line Replaceable Units (LRUs), which constitute of various electro mechanical systems, across various aircraft at fleet level with details such as shelf life, calendar life, maintenance schedule, Pre-Installation (PI) checks, serial part number etc. In addition, maintenance and service documents such as Flight Safety Certificate, LRU log cards, maintenance due list etc. could be generated using CAMMS. CAMMS in association with Failure Reporting Analysis and Corrective Action System (FRACAS) will offer a framework for repair and maintenance studies that can be extended to Performance Based Logistics (PBL) in future.

Experimental investigation of quality interactions in material processing

C. Phaneendra Kiran, Shibu Clement and H. Chelladurai

This paper presents a methodology for quantification and evaluation of quality interactions in material machining process. The quality of a surface after turning operation depends on the quality of CNC machine structural components and also on the interactions between them. In this paper a methodology for finding quality interactions between the structural components is presented. The full factorial experiments design (135 experiments) has been carried out for measuring the responses of accelerometer and strain gauge. This data is analyzed using the analysis of variance (ANOVA) and interaction plots. The interactions which are significant are quantified using the ANOVA results. The quantified interactions can be substituted in the quality permanent to find a quality index. The resultant quality index is useful to the customer in evaluating the overall quality of a material machining process for optimal cutting parameter combination.

Application of finite element analysis in effective design of flight control circuits in a typical light transport aircraft

Prashanth Ramanathan and Abbani Rinku

In small commuter category aircraft, the control surfaces viz., Aileron, Elevator and Rudder are operated using mechanical flight control system consisting of elements like push-pull rods, cables, pulleys, quadrants, etc. There is a considerable reduction in stiffness of the flight control circuit due to the stretch in these elements, resulting in control surface deflections lesser than desirable values. This paper focuses on the application of Finite Element Analysis (FEA) in design, analysis and optimization of flight control circuits of a typical Light Transport Aircraft (LTA) using FEA software Altair Hypermesh and MSC Nastran. Various Finite Element Modeling techniques have been extensively used in this study to simulate the control circuit mechanisms that exist on the aircraft. The stiffness and stretch values obtained from the analysis are in good agreement with the experimental results obtained from ground tests conducted on the LTA. The methodology proposed in this paper minimizes the time and effort in designing and implementing an optimum control circuit, and also eliminates the need for extensive ground testing.

Locality sensitive clustering in high dimensional space for images

Haolin Gao, Bicheng Li, Gang Chen and Yongwei Zhao

The main clustering algorithm in image clustering especially visual image clustering is k-Means currently. But the limitation of k-Means seriously deteriorates its feasibility in incremental large image set. To improve the feasibility, we propose a Locality Sensitive Clustering method in high dimensional space based on distance and separability preservation property of random projection. It first generates the multiple hashing functions, and then projects data points to get bucket indices, and then select proper quantification interval to merge the bucket indices, at last decide the cluster labels for each point. The experiments on synthetic data set showed that our method perform almost as well as k-Means algorithm and on image data set perform slightly worse than k-Means algorithm about accuracy. But its advantage is in low memory cost, fast running speed and dynamic clustering. So Locality Sensitive Clustering can be used to clustering data, especially in high dimensional space.

Thermodynamic and environmental analysis of a fuel cell power system used in a building in Ahvaz

M. Pourmahmoud, M. Ojakeh and M. K. Hafshejani

Herein, a fuel cell power system that works in CHP mode has been considered to provide electrical, heating, cooling and domestic hot water loads of buildings. The buildings tolerate hot summers and mild winters during their operation life. In previous research, the PEM fuel cell system was designed and number of fuel cell stacks to provide the required energy of the building was estimated. As a complementary investigation, the thermodynamic and environmental analysis of the mentioned system has been conducted in this research. Results have shown that for a 12 fuel cell stacks at a nominal capacity of 8.5 kW, the mass production of monoxide carbon, monoxide nitrogen and dioxide carbon are equal to 1272.621 (kg/year), 1609.056 (kg/year) and 26107.23 (kg/year), respectively. The mass production values are acceptable since it is within limitation ranges mentioned by many environmental protocols.

Role of clean development mechanism to promote wind energy: A case study of Tamil Nadu based wind power project

Shruti Singh and Rajesh Kumar

Keeping the issue of climate change in mind, wind energy is vital as this has an attractive attribute that the fuel is free of emission and this will be the case for the project lifetime and beyond. The Clean Development Mechanism (CDM) is one process which assists the development of wind energy as well as other renewable energy. The objective of this paper is to focus on the attractiveness of the CDM for a wind power project, which is positioned in Tamil Nadu, India through the calculation of Certified Emission Reductions (CERs).

Developing a conceptual road safety framework to construct road safety regression outcome

Abstract:

Road safety and accident occurrences face some of the most difficult sustainability challenges in transportation industries. In order to secure its continued social license or its level of acceptance or approval to operate, the industry must response to these challenges by engaging its many different stakeholders to address their sustainability concerns. To achieve this conceptual road safety framework consisting of seven factors determining exposure to risk (resulting from travel behaviour), risk (injury risk and crash risk), task, driver, vehicle, hazard and road condition was constructed. It was from the framework that the model was developed to construct a road safety road safety outcome based on multiple regression analysis, the number of road deaths that occurred in the case study country Malaysia for the period of (1995-2010) was plotted as the depended variable against data for the seven chosen factors (independent variables) for the same period of study and a regression equation (significant at 95 percent confidence interval, R2 = 0.812 of the form: D =2231.481+ 2.224X₁ - 160X₂ + 0.0201X₃ + 5.166X₄ + 13.939X₅ - 16.890X₆ - 0.747X₇ was developed as a guide for the stake holders in the transportation industries as a measure of safety performance.

A multi-agent-based Qos-Driven web service discovery and composition framework

Manoranjan Parhi, Binod Kumar Pattanayak and Manas Ranjan Patra

Web service has been playing a magnificent role in the field of application development. It facilitates giving a global touch to standalone applications components to interact with each other via interfaces and form larger application systems. Web service users who seek for single web service or composition of web services face a lot of problems regarding its discovery. Discovery of suitable web services has become a challenging issue due to the increasing number of selection parameters and constraints. This paper deals with a hybrid multi-agent based web service discovery mechanism which involves an artificial intelligence approach to efficiently interpret the user requirements based on both functional and non-functional demands and fuzzy constraints. The proposed model utilizes the services of intelligent software agents. Some of the agents like the reputation agent analyses the popularity of web services and assign ranks to the web services based on user feedback and statistical information. The behavior of individual user is being tracked, from which the intelligent agent interprets the fuzzy requirements of users through set of logical and analytical calculations whereas the composition agent provides flexibility to the user for custom composition of web service packages using different individual web services. In brief, we present an automated customer-centric web service discovery and composition approach which aims in an efficient web service discovery and composition followed by customer satisfaction using multi agents.

Impact resistance and strength reliability of fiber reinforced concrete using two parameter weibull distribution

G. Murali, A. S. Santhi and G. Mohan Ganesh

In this study, an attempt has been made to investigate the impact resistance of fiber reinforced concrete (FRC), subjected to drop weight test in accordance with the procedure suggested by ACI committee 544. For this, four samples were prepared from each series of mix containing crimped and hooked end steel fibers of 1 mm diameter and 50 mm length in various proportions viz., 0%, 0.5%, 1.0% and 1.5%, with a water cement ratio of 0.42. In the view of variations of test results, two parameter weibull distributions were performed to analyze the experimental data and the impact failure strength was presented in terms of reliability function. The results indicated that incorporating steel fiber to concrete increased the impact resistance and change the failure pattern from brittle to ductile mode. Also results indicated that the weibull distribution allows the researchers to describe the impact failure strength of FRC in terms of reliability and safety limits. This provides a greater ease for designers by eliminating the number of experiments.

This paper presents a comparative analysis of the harmonics generated in the output waveforms of 3-phase H-bridge cascaded multi-level inverter topology using Sinusoidal Pulse Width Modulation (SPWM) techniques. The Alternate Phased Opposite Disposition- Pulse Width Modulation (APOD-PWM) is one of the best SPWM schemes in achieving reduction in the Total Harmonic Distortion (THD), which is the major parameter often used to assess the suitability of an inverter. However, due to the closely set carrier arrangement, the APOD-PWM produces high THD especially at switching frequencies above 1-kHz. In this paper, a Gapped APOD-PWM is proposed. The switching sequence is similar to the APOD-PWM technique, but it has smaller switching angle. This reduces the switching overlap at boundary positions and hence the THD. The technique was simulated using the MATLAB-SIMULINK toolbox. The output current and voltage signals were evaluated and the THD was computed using SIMULINK-FFT tool. Results show that the proposed technique is able to further reduce THD at all switching frequencies.

Equilibration of the Wheatstone bridge by the pulse-width modulation method

Aleksandr Vitalievich Vostrukhin and Elena Arturovna Vakhtina

Possibility of an equilibration of the resistive sensor bridge scheme (the Wheatstone bridge) is investigated by the Pulse-Width Modulation method. On the basis of imitating modeling and experiment the transformation process of the resistive sensor resistance into binary code by Microcontroller Measurement Converter is considered. The equilibration process of the Wheatstone bridge circuit is realized with using Pulse-Width Modulator and the Analogue Comparator built in the microcontroller. The offered method allows combining functions of Analog-to-Digital Conversion with the Wheatstone bridge equilibration that is very important at creation of intellectual sensors.

Comparative performance of selected Ear-Corn drying techniques

Junaid Iqbal and Munir Ahmad

Drying of the ear-corn is a difficult process, which usually depends on manager experience. As a result, there is large chance to improve the method in terms of preserving quality, decreasing cost, and increasing capacity. A study was conducted at Okara and Pind Dadan Khan during the October 2010 and June 2011, respectively. The objectives of study were to evaluate selected ear-corn drying techniques namely sun drying, solar passive ear-corn drying, and heated-air ear-corn drying and to perform the cost analysis of these three techniques, and analyzed the comparative performance of these techniques based on field data. Solar passive dryer was constructed in Okara and Pind Dadan Khan to dry ear-corn; the test results indicated that dryer was found capable to dry 0.5 tons of ear-corn from 26.1 to 18.9% moisture content in October in four days and from 26.4% to 20.1% in June in two days. During sun drying 25.9% moisture content was decreased to 19.1% in October and 25.6% to 18.4% in June. A heated-air dryer developed at Agricultural and Biological Engineering Institute, National Agricultural Research Centre, Islamabad was also evaluated. The tests results showed that dryer had capacity to dry 4 tons ear-corn from 26.5 to 20.4% moisture content in 9 hours using heated air. Finally, the cost analyses of these three ear-corn drying techniques were also performed.

Investigation of abrasion and morphology of Rubber/Nano titanium oxide nanocomposites

Alireza Yekrangi, Mohammad Afrasiabi, Ameneh Langari and M. K. Hafshejani

Rubber/Titanium oxide nanocomposites might be considered as potential materials in medical and industrial applications due to the flexibility of the polymer and antibacterial properties of nanometric additive. In this research paper, the morphology and physical properties of nanocomposites based on Styrene Butadiene rubber have been investigated in the presence of nano titanium oxide additive. The nanocomposites have been prepared by mechanical blending using two roll mills. Nano Titanium oxide particles have been added to Styrene Butadiene rubber and the abrasion and thermal properties have been surveyed. Optical microscopic observation and scanning electron microscopic pictures have been used to investigate the morphology of nanocomposites based on rubber. Abrasion test results showed that the nano Titanium oxide particles could enhance the abrasion resistance of Styrene Butadiene rubber matrix due to appropriate properties of nano Titanium oxide particles.

Synthesis of silver nanoparticles

Raid Salih Jawaad, Khalid F. Sultan and Ali H. Al- Hamadani

Widely Silver nanoparticles have been investigated because they exhibit unusual optical, electronic, and chemical properties, depending on their size and shape, thus opening many possibilities with respect to technological applications. The silver nanoparticle is one of the inorganic nano materials which is a good antimicrobial agents. The researcher found that the bactericidal nano materials have opened a new epoch in pharmaceutical industries. Silver nanoparticles are the metal of choice as they hold the promise to kill microbe’s effectively and effect on both extracellularly as well intracellularly, the researchers by using different methods, manufactured silver nanoparticles with spherical, octahedral, tetrahedral, hexagonal, cubic, wire, coaxial cable, triangular prism, disc, triangular mark, belt, and shell shapes.

Grid computing uses the concept of resource sharing which is used in virtual machines and cores, to enhance the capacity of a parallel CPU. The energy utilized and the time taken for executing a task is the most important criteria to be considered during the work-flow scheduling. This paper recommends the frame work of PERMA-G implementing the techniques of optimization, modeled after the fuzzy bee colony method as a solution to the issues of energy utilization and task completion time by the virtual machines. It replicates the honey bees’ nature on fuzzy to dynamically calculate the time taken to run the computational task schedules to decrease the power utilization, cost and the task completion time. Performance evaluation is on the basis of service for Grid, power utilization and process.