bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Scheme for Fredholm Integral Equations Optimal Control Problems
Authors: Sanchooli Mahmood , Fard Omid Solaymani
Published: October 2011

This paper deals with a class of optimal control problems governed by linear Fredholm integral equations. A direct scheme based on the Taylor expansion and parametrization to calculate an approximate-analytical solution of the problem is proposed. This method produces an approximation with a controlled level of accuracy. Moreover, a hybrid algorithm to show the procedure of the scheme is given. The convergence of the proposed scheme is also discussed in detail. Some numerical examples illustrate the potential, efficiency and accuracy of the algorithm.
Numerical Investigation of Formation and Development of in-Cylinder Rotational Flow in a Spark Ignition Engine
Authors: Yousefi M. , Ommi F. , Farajpour Mehdi
Published: October 2011

In this study a CFD model of a spark ignition (SI) engine was prepared using KIVA-3V code and experimental data to investigate the in-cylinder flow field. The whole engine cycle was simulated and the validity of the model was ascertained by experimental result of in-cylinder bulk pressure and flow field visualization. The flow pattern inside the cylinder was investigated qualitatively to deepen our understanding of the formation and development of rotational flow prior to the ignition. Both tumble and swirl were observed in the flow field. The numerical results showed that turbulence intensity in the section with stronger vortex is higher.
Numerical Prediction of Natural Convection Heat Transfer through Porous Media by the Lattice Boltzmann Method
Authors: Mohd Irwan Mohd Azmi , Azwadi Nor C. Sidik
Published: October 2011

In this paper, we report an efficient numerical method to predict thermal fluid flow behavior in a square cavity filled with porous medium. The conventional Navier-Stokes equations are solved indirectly, i.e by the lattice Boltzmann formulation with second order accuracy in space and time. Numerical experiments were performed with different values of medium porosity and Rayleigh number to investigate the effect of these dimensionless parameters on the thermal fluid flow behavior in the cavity. In the current study, we found that the dynamics and the structure of primary vortex are significantly affected by the Rayleigh number and the medium porosity.
Development a Device for Measuring Soil Mechanical Properties
Authors: Shahgoli Gholamhosein , Azar J. Nasrollahi , Abbaspour-Gilandeh Yousef
Published: October 2011

In tillage operations to know soil reaction force on the tools working inside soil and under agricultural vehicle tires, soil mechanical parameters should be determined. Measurement and determination of soil mechanical parameters will be helpful for optimum designing of tillage tools to decrease required energy. An experimental device was developed at the University of Mohaghegh Ardabil which is able to conduct three soil mechanics tests of sinkage, penetration and shear, by which soil cohesion, internal friction, stiffness, soil constant and strength were determined. For sinkage and penetration tests an electromotor power was translated to a rectangle plate via a translating system such that moves plate or cone penetrometer vertically and forces it in soil. While fore shear test it moves shear plate horizontally as plate shears the soil. Required forces for sinkage, penetration and shearing were measured by loadcell and vertical and horizontal displacements were measure using linear potentiometer (LVDT). All data logged to a loptop via a data logger. All mentioned parameters for a type of soil were computed desirably related tests.
MEMS Vector Hydrophone Structual Error Analysis and Testing
Authors: Shi Gui Xiong , Zhang Guo Jun , Liu Xi Bao , Wang Xiao Yao , Xu Jiao
Published: October 2011

In this paper, we analysis the working principle of a cilium-type MEMS vector hydrophone, by analyzing we obtained the errors of the vector micro-sensor are deviations from column cilium. Since the structure is mainly picking up sound vibrations by the cilium, the piezoresistor which on the beams connected by Wheatstone bridge circuit will output the signals, so the deviation of cilium cylinder have greater impact the sensitivity in both directions of vector hydrophone. Through theoretical calculation and finite element simulation of the sensitive structure of the error analysis. By the structure of the hydrophone error test ,we obtained the sensitivity of X direction is 0.755mv / g, the sensitivity of Y direction is 0.683mv / g, The relative sensitivity error of two directions is 9.5% which is close to the simulation results. Finally, this paper give a solution to the error. (Abstract)
Attractive Nonlinear Schrödinger Equation and Bose-Einstein Condensate in Phase Space
Authors: Lu Jun
Published: October 2011

In this paper, we solve the rigorous solutions of attractive nonlinear Schrödinger equation which models the Bose-Einstein condensate, within the framework of the quantum phase space representation established by Torres-Vega and Frederick. By means of the “Fourier-like” projection transformation, we obtain the eigenfunctions in position and momentum spaces from the phase space eigenfunctions. As an example, we discuss the eigenfunction with a hypersecant part.
Star Grain Regression under Spin Induced Acceleration Effect
Authors: Soe Hlaing Tun , Xiang Hong Jun
Published: October 2011

Spinning is used in some of solid rocket motors to increase the flight trajectory precision or for stability requirements. The angular acceleration due to the spin effect increases the burning rate of solid propellant and changes the motor performance by increasing the operating pressure and decreasing the burning time. So it is important to know the grain regression taken place in the solid propellant rocket motor in the acceleration field. In this study, we represent the grain regression analysis of two-dimensional axis-symmetric star grain configuration of the solid propellant rocket motor under spin induced acceleration effect to study how the spin affects on the internal ballistics of the solid rocket motor. Grain regression is done by two methods - geometrical approach and numerical approach. The burning rates on the propellant surface are different with its radial distance, acceleration vector angle and surface slope when the rocket is spinning. With the different burn rates on the propellant surface, the propellant surface perimeter and port area are computed by using the numerical method, and the results are compared with that of constant burn rate.
ICA and BP Neutral Network Based Fault Detecting Algorithm for Large Engine
Authors: Jiang Yong Mei
Published: October 2011

With the rapid development of information technology, some experience intensive work like fault detecting has been greatly improved by information technology. Traditional fault detecting method depends on the knowledge of expert to some extent which can not satisfy the requirement of large engine, which is with poor testability. Regarding this problem, this paper apply the technology of Independent Components Analysis (ICA) and BP neutral network to the process of fault detecting, the accuracy and efficiency are greatly improved with these methods, and the experiment result has proven the validity of the method described.
Tilt Angle Optimization for Grid Interactive Solar Photovoltaic Array
Authors: Chauhan Ranchan , Thakur N.S. , Chamoli Sunil
Published: October 2011

The overall performance of any solar energy project largely depends upon the available solar radiations, inclination and orientation of solar collectors. Presented in this paper is the analytical study on optimum tilt angles and lifetime differential savings for a distributed 200 kW grid connected mono-crystalline solar PV system operating at Khatkar Kalan, Punjab, India. The optimum tilt angles for monthly, seasonally and yearly basis is carried out by searching the values of tilt angle for which electric power output is maximum for a particular day or a specific period using energy conversion model. The results reveal that the yearly optimum tilt angle for the SPV plant at Khatkar Kalan is 36° which is 4.58° higher than the latitude angle. The power output from the array increases with increase in angle of tilt for winter months whereas the trend is reverse for the summer months. In winter months the maximum power output is achieved for the array surface with a tilt of angle 13° - 23° higher than the local latitude while for summer months the maximum power output is achieved at 16° lower than the latitude angle. The optimum tilt angles maximizing monthly power output for south facing surface shows that the monthly optimum tilt angle varies from 15° to 55°. Also the parametric analysis for some influential factors such as latitude of location and reflectivity of ground surface is explored.
Experimental Investigation of Manifold Induced Flow Maldistribution in U-and Z-Turn Flow Configurations
Authors: Ingle Sachin B. , Maurya R.S.
Published: October 2011

In many process equipments and mechanical system where a flow needs to be distributed among several outlets, the design is generally based on the assumption that the fluid is uniformly divided among them but practically in never happens. A non-uniform flow distribution imposes a serious design limitation in terms of rise in pressure drops and decrease in thermal performance of the system. Reynolds number being a characterizing parameter of pipe flow is expected to play a significant role in flow maldistribution pattern also. This paper present an experimental study performed on multi channel U-and Z-turn flow configurations where the flow is varied in the practical range of 20000 < Re < 35000. Result shows the presence of maldistribution. It is found that the Re plays an important role in characterizing the flow in terms of channel velocity, axial velocity in header and flow distribution pattern in a specific channel. Maldistribution effect is found to be dominant in the central region in U-turn flow and peripheral region in Z-turn configurations.
Optimization of New Metal Gasket Design Based on Contact Width Involving Contact Stress Consideration
Authors: Choiron M. Agus , Haruyama Shigeyuki , Kaminishi K.
Published: October 2011

The relationship of contact width and leakage had been found as design concept to optimize new metal gasket. By using this design concept, the limits of contact width for no leakage can be chosen. The optimize gasket shape can be developed by increasing of contact width. In this study, a gasket shape was optimized based on contact width as design concept and involving contact stress consideration. The design of experimentation (DOE) Taguchi method is used to analyses the effect of each parameter design and predict optimal design of new 25A metal gasket. The L18 orthogonal array was concerned to design experimental matrix for seven factors with three levels. The optimum design of gasket at 0 MPa mode is the model with OH = 4 mm, p1 = 3.5 mm, p2 = 4 mm, p3 = 4 mm, t = 1.2 mm, R = 3.5 mm and h = 0.4 mm. The optimum design of gasket at 400 MPa mode is the model with OH = 3 mm, p1 = 3.5 mm, p2 = 4.5 mm, p3 = 4.5 mm, t = 1.8 mm, R = 1.5 mm and h = 0.3 mm.
A New Computerized System for Piercing and Bending Progressive Die Design
Authors: Farsi Mohammad Ali
Published: October 2011

A Progressive die is used to transform flat strips of sheet metal into a formed part. This transformation is performed progressively by a series of stations that cut and bend the material into a desired shape. The progressive dies reduce the time and cost of producing complex sheet metal components. The design and manufacture of these dies are difficult. CAD/CAM systems have been proved very useful tools for this task. In this paper, a new system for design of the piercing and bending progressive die is described. In this system, piercing and bending operation are separated and the sequencing of each type is done individually. In this system first sequence of the piercing stations are determined then bending operations are sequenced based on a classification and fuzzy algorithm. Also, neural network systems are used to determine final angle of bends and die parameters. The capability of the system is shown using a sheet metal component.
Planar Maximal Covering Location Problem with Inclined Ellipses
Authors: Charkhgard Hadi , Jokar Mohammad R. Akbari
Published: October 2011

aximum coverage location problem is considered in this study. Extension of this problem is investigated for situations that coverage areas are elliptical; these ellipses can locate anywhere on the plane with any angle. Mixed integer nonlinear programming (MINLP) is applied for formulation. This problem can be used in many practical situations such as locating wireless transmitter towers. A heuristic algorithm named MCLPEA for solving this problem was designed. This algorithm can produce very good results in efficient running time. Finally, the comparison of the results for this study was carried done.
Design of Alarm System with Pyroelectric Infrared Sensor
Authors: Shang Xiao Yan , Wu Jian , Wang Xing
Published: October 2011

Based on pyroelectric infrared sensor working principle, the passive pyroelectric infrared alarm system is designed, which is mainly used for safety of residence house to detect whether outsiders enter or not. This system is made of pyroelectric infrared sensor, Fresnel lens and monitoring circuits. The concealment of infrared is well applied on the circuits , amplifying and filtering circuit , infrared signal processing circuit are designed, then the voice chip is utilized to simulate alarm voice for warning thieves and burglars .After many experiments, This system has sensitive response , high anti-interference ability and safe and reliable performance.
Computed Extinction Limits and Flame Structures of Opposed-Jet Syngas Diffusion Flames
Authors: Shih Hsin Yi , Hsu Jou Rong
Published: October 2011

This paper reports a numerical study on the extinction limits and flame structures of opposed-jet syngas diffusion flames. A narrowband radiation model is coupled to the OPPDIF program, which uses detailed chemical kinetics and thermal and transport properties to enable the study of 1-D counterflow syngas diffusion flames over the entire range of flammable strain rates with flame radiation. The effects of syngas composition, strain rate, ambient pressure, and dilution gases on the flame structures and extinction limits of H2/CO synthetic mixture flames were examined. Results indicate the flame structures and flame extinction are impacted by the composition of syngas mixture significantly. From hydrogen-lean syngas to hydrogen-rich syngas fuels, flame temperature increases with increasing hydrogen content and ambient pressure, but the flame thickness is decreased with ambient pressure and strain rates. Besides, the dilution effects from CO2, N2, and H2O, which may be present in the syngas mixtures, were studied. The flame is thinner and flame temperature is lower when CO2 is the diluents instead of N2. The combustible range of strain rates is extended with increasing hydrogen percentage and ambient pressure, but it is decreased the most with CO2 as the dilution gas due to the dilution effects. Complete flammability limits using strain rates, maximum flame temperature as coordinates can provide a fundamental understanding of syngas combustion and applications.
An Experiment on Electric Power Steering (EPS) System of a CAR
Authors: Akhtaruzzaman M. , Razali Norrul’ Aine Binti Mohd , Rashid Mohd. Mahbubur , Shafie Amir Akramin
Published: October 2011

This paper describes an experiment on Electric Power Steering (EPS) system of a car. Nowadays EPS system can be considered as a Mechatronics system that reduces the amount of steering effort by directly applying the output of an electric motor to the steering system. In this paper, the constitutions, operational mechanism and control strategies of EPS system are introduced. A potentiometer measures driver input to the steering wheel, both direction and rate of turn. This information is fed into a microcontroller that determines the desired control signals to the motor to produce the necessary torque needed to assist. Although an electro hydraulic power assisted steering system can be used to reduce the fuel consumption, but the maximum benefit can be obtained if electronic system is applied instead of the hydraulic mechanism. The paper shows that a good power steering control technique is achieved by designing a Mechatronics system. The experimental results for the designed EPS system are also analyzed in this paper.
Design of a Wind Water Heater
Authors: Al-Nimr M. A. , Al-Shohani Wisam A.M.
Published: October 2011

A new design of a wind water heater (WWH) is presented. In this new system, the wind energy is directly converted to thermal energy used to heat the water. The wind energy is converted to frictional thermal energy by dissipation within a thin layer of oil. The oil is filled in an annular gap confined between two horizontal concentric cylinders with different diameters; the outer insulating cylinder is rotating while the inner cylinder is fixed. The heat generated is transferred into the inner cylinder then to the heat exchanger. The heat transfer fluid is carrying the heat from the heat exchanger to the water storage tank by mechanical pump. A mathematical model is proposed to model the system mechanical and thermal behavior. The theoretical model has been solved analytically to estimate the amount of thermal energy generated by the system based on a given wind design speed at the site. The theoretical performance of the proposed heater is analyzed and the effects of different design parameters on the heater performance are investigated. The theoretical predictions of the system performance show that the efficiency of proposed wind water heater at design wind speed is equal to 34.8%. The relatively low conversion efficiency of kinetic wind energy to sensible thermal one is due to the limitation imposed by the windmill performance.
Compensation of Input Disturbance in EPS System Using Sliding Mode Observer
Authors: Son Byeongjeom , Park Gwangmin , Kum Daehyun , Lee Seonghun
Published: October 2011

Electric power steering is developed to reduce effort by providing steering assist to the driver of a vehicle. In recent years, a research regarding returnability is performed in order to improve driver's steering feeling. Returnability is affected to friction force in EPS system and reaction force through tire and rack. Usually in the EPS system, friction and Reaction force are uncertain components which are hard to measure. This paper introduces both estimation using sliding mode observer and control algorithm using input disturbance compensation for returnability of EPS system. And simulation confirms the results of the estimation and control algorithm.
Application of Neural Networks and PID in on Line of Real-Time Temperature Control System
Authors: Elfandi Suleiman A. , Osman Mahmoud A. , Ali Nasser , Agab Nuri
Published: October 2011

The Heat Process Trainer PT326 (Feedback UK) model is obtained by using two different techniques one by the Ziegler-Nichols approximating method and the other with the system identification method. The Data acquisition card EC641 I/O PT326 is developed and tested. it can be used as an interface between PC and any similar controlled system. The “velocity” form of the PID controller algorithm is implemented in real time where this algorithm is an ideal of solving the bump less transfer mechanism between manual and automatic control operation and the implementation of anti-reset windup algorithm. The method of back propagation neural network algorithm online gives very good results with neither steady state error nor overshoots.
Improving Elmore Model of RLC Networks for Applying to SWCNT Interconnects
Authors: Behtoee Behrouz , Faez Rahim
Published: October 2011

Elmore delay has been widely used as an analytical estimate of the interconnect delays in the performance-driven synthesis and layout of VLSI routing topologies. In this paper, Closed-form solutions for the 50% delay, rise time and overshoots of the step response of distributed Single Wall Carbon Nanotube (SWCNT), which consists RC and RLC parts, are presented for the first time. The proposed approach retains both efficiency and simplicity of the equivalent Elmore model with significantly improved accuracy, through surface fitting (3D) instead of curve fitting (2D).
Comparison of Multi Agent Based PSO Approach for Optimal Power Flows with Security Constraints
Authors: Kumar K.Ravi , Anand S. , Sydulu M.
Published: October 2011

This paper proposes a comparison of new evolutionary multi agent based particle swarm optimization algorithms for solving optimal power flows with security constraints (line flows and bus voltages). These methods combine the multi agents in two dimensional and cubic lattice structures with particle swarm optimization (PSO) to form two new algorithms. In both Two Dimensional Lattice Structured Multi Agent based Particle Swarm Optimization (TDLSMAPSO) and Cubic Lattice Structured Multi Agent based Particle Swarm Optimization (CLSMAPSO), an agent represents a particle in cubic lattice structure to PSO, and a candidate solution to the OPF problem. All agents live in a square and cubic lattice like environments, with agents fixed on a lattice point in the ascending order of their fitness value. In order to obtain the optimal solution, each agent in cubic and square lattice competes and cooperates with its neighbors. Making use of these agent-agent interactions, CLSMAPSO and TDLSMAPSO realizes the purpose of minimizing the objective function value. CLSMAPSO and TDLSMAPSO realizations were applied to IEEE 30 bus system. Simulation results show that proposed approaches gives better solution than earlier reported approaches in quick time.
Trajectory Optimization of Hypersonic Vehicle Using Gauss Pseudospectral Method
Authors: Tawfiqur Rahman , Zhou Hao , Sheng Yong Zhi , Younis Ya Min , Zhang Ke Nan
Published: October 2011

The paper presents a gauss pseudospectral solution for the trajectory optimization problem of a hypersonic vehicle. Determination of optimal trajectory of a hypersonic vehicle is of great interest due to the different path and boundary conditions that need to be met for high accuracy. Recent researches show that pseudospectral methods are capable of providing high accuracy in computationally efficient manner. The hypersonic vehicle optimized here is accelerated through solid rocket propulsion to mach 3.5 and after ejection of the rocket motor it is accelerated to mach 6 where it starts cruise for reaching target. The flight profile which is divided into boost, ascent, cruise and dive phase is optimized using multi-phase implementation programme of gauss pseudospectral method GPOPS. The optimization is carried out in 2D assuming non-rotating flat earth assumption and considering propulsion, dynamic and atmospheric constraints. The results are then analyzed for max range and max final velocity and hit angle. The results are found to be feasible.
Comparative Evaluation of Mode Combination Methods in Seismic Analysis Using Response Spectrum Method for Tank Structure Using FEA - Seismic FEA
Authors: Shelke Sujay , Vankudre H.V. , Patil Vinay
Published: October 2011

Typical seismic analysis using response spectrum method involves several steps from the initial step of extracting the modes. At the initial stage Eigen values are extracted corresponding to the modes of vibration. These give us Eigen vectors which are a series of relative displacement shapes; however these do not correspond to real displacements or stresses. Participation factors asses these Eigen vectors and grades them according to contribution they will have to the overall solution. Based on the spectral seismic acceleration, participation factor is used to calculate the mode coefficient, which is more of a scaling factor to give physical meaning to the values. Once the modes are extracted, the key issue is of combining these modes to obtain the seismic response. The modes cannot be added algebraically in reality as all the modes do not occur at the same time. Hence we employ methods which can add the modes in a more realistic manner. The objective of this paper is to do a comparative study of various mode combination methods with a focus on tank structures and study the effect of various geometrical parameters on the combination methods
A Tool for Decision Making in K-Out-of-N System Maintenance
Authors: Vintr Zdenek , Valis David
Published: October 2011

The paper deals with possibilities of maintenance optimisation of k-out-of-n systems. The first part of the paper briefly analyses influence of preventive maintenance concept on reliability of k-out-of-n system and presents possibilities of preventive maintenance optimisation with respect to maintenance costs. The second part of the paper presents a suggested method of maintenance optimisation in the case of a processing machine for dosing tiny loose material and smaller piece goods. The method takes into account not only maintenance costs but also production losses caused by a prospective failure of the system. The proposed method facilitates decisions on maintenance intervals modification and the range of maintenance from the economic point of view.
Selection of Grippers-A Fuzzy Graph Theoretic Approach
Authors: Goyal Sanjeev , Grover Sandeep
Published: October 2011

the optimum selection of grippers is a complex task as it involves large tangible and intangible attributes and also availability of large options in the market. In this present work, an endeavour has been made to quantify intangible attributes by using fuzzy MADM approach and then overall numerical index has been find out by using Graph Theoretic Approach (GTA) So, that the customer can visually compare different models.
Design and Implementation of a System on FPGA for Fault Detection on Industrial Machines through Vibration Sensing
Authors: Kannoju Praveen Kumar , Krishnaveni Krishnaveni
Published: October 2011

This paper presents the design and implementation of a system for detecting the microscopic faults and defects present in the electrical machinery using the vibration analysis. Vibration analysis based on mechanical bearing frequencies in industrial machines is currently used to detect the presence of a fault condition. Since these mechanical vibrations are associated with variations in the physical disturbances of the machine, the air gap flux density is modulated and peak amplitudes are generated at predictable frequencies related to the electrical supply and vibration frequencies. Spartan3E FPGA was used in this process to reduce the time of detection and to increase the accuracy in displaying the fault position. Induction motor HS-1 by High Speed Motors is taken as the device under test to perform the vibration analysis and draw the results. The device SI-100 by Syscon Instruments is the sensor used to extract the analog information of interest from the motor during the implementation. In addition all this phenomena is also tested using LabVIEW2009 and NI-ELVIS to check the accuracy of the results.
Walking Assist Device: The Electronic and Firmware Design
Authors: Sim K.S. , Low K. Y. , Tso C. P. , Ting H. Y. , Lee C.T.
Published: October 2011

This project aims to design and develop a working prototype of a walking assist device. Spring and brushed DC motors are adopted to assist human being standing or walking by lessening the amount of force subjected to the knee. Two DC motors are controlled by the high current capable motor driver which is specifically designed for heat management. Moreover, an 8051 microcontroller provides interface between the sensor ADC input, keypad manual input, intelligent controller and the DC motors.
Magnetoresistance Effects for the Inhomogeneous Perovskite System of Ag Doped La0.833Na0.167MnO3
Authors: Wu Jian
Published: October 2011

The transport properties of the inhomogeneous system (1/4) Ag2O-La0.833Na0.167MnO3 (LNMO/Ag) have been systematically studied. X-ray diffraction patterns show that the LNMO/Ag sample is the two-phase composite and consists of a magnetic La0.833Na0.167MnO3 (LNMO) perovskite phase and a nonmagnetic Ag metal phase. The resistivity of the sample decreases dramatically with Ag added into the pure perovskite LNMO manganites. For the LNMO/Ag sample, the Curie temperature TC is 331 ± 2 K and slightly higher than that of the LNMO sample (323 ± 2 K). Due to the dope of Ag metal, the room temperature magnetoresistance effect is enhanced significantly (from 7% for the pure LNMO manganites to 23% for the LNMO/Ag sample under a relative lower field of 0.5 T and from 37.5% for the LNMO sample to 41 % for the LNMO/Ag sample under a high field of 6 T at the temperature of 330 K. In the low temperature regime, the magnetoresistance ratio of the LNMO/Ag sample is smaller than that of the LNMO sample, which is contrary to the magnetoresistance effect in high temperature. The effects are discussed qualitatively by use of a model which is based on the relative change among the intrinsic magnetoresistance effect and the extrinsic magnetoresistance effect.
Photocatalytic Activity of TiO2 Nanotube Modified by Cobalt
Authors: Yang Xin Sheng , Kim Hern
Published: October 2011

Cobalt modified TiO2 nanotube was prepared by wet impregnation method from anodized nanotube. The microstructure and phase characteristic were studied by SEM, EDX and XRD analysis. The photocatalytic degradation of methylene blue under UV illumination was studied. Enhanced degradation efficiency could be obtained after sodium borohydride reducing. For the samples using low concentration of CoCl2 in wet impregnation process, the degradation efficiency increased with the increase of CoCl2 concentration and for high concentration, the degradation efficiency decreased. With increasing the post-treatment temperature, the degradation efficiency decreased.
Analysis and Comparison of Dispersion Properties of Hexagonal and Square Lattice Photonic Crystal Fiber
Authors: Dabas Bhawana , Rajput Monika , Sinha R. K.
Published: October 2011

In this paper, we compare the dispersion properties (flattened, zero and negative dispersion) and effective area in hexagonal and square lattice PCF with different hole-to-hole spacing (Λ) and air hole diameter (d) by using Fully Vectorial Effective Index Method (FVEIM). The analysis is carried out in wavelength range from 1.3 µm to 1.6 µm. We also use plane wave expansion method for comparison of effective cladding index in both above lattices.
Effects of Negative Bias on the Structure of Ti Film and its Adhesiveness to the Base by Plasma
Authors: Lai Qi , Huang Shuang Hua , Lan De Jun , Zou Min , Luo Xue Ping
Published: October 2011

Ti film on AISI 201 was prepared by plasma. The film was characterized and analyzed by using a variety of analytical techniques, such as XRD, SEM and universal test machine. Ti films were deposited on AISI 201 stainless steel substrate, it was found that of Ti film has a different microstructure in various negative bias. And film density is connected with bias. When bias rose from the 15V to 100V, the film density increased from 3.82 g/cm3 to 4.28 g/cm3. After bias rose from the 100V to 180V, film density decreased from 4.28 g/cm3 to 4.13g/cm3. And also, due to the microstructural changes, the adhesiveness of Ti films at the AISI 201 increased from 1.16 MPa to maximum of 3.87 MPa, and then decreased. There is a similar maximum value of approximately 7.53 MPa at the AISI 304.
Effect of Montmorillonite and Maleic Anhydride Grafted Polypropylene Content on Polypropylene/Wood Flour Composites
Authors: Khanjanzadeh Hossein , Tabarsa Taghi
Published: October 2011

In this study the effect of nanoclay (0, 3 and 5 wt %) and grafted anhydride maleic with polypropylene (MAPP, 3 and 5 wt%) on physical and mechanical properties of polypropylene/wood flour nanocomposite was investigated. For manufacturing of these composites after melt compounding of the material they were converted to wood plastic granules in extruder and placed in hot press. The results showed that with increase of nanoclay physical (thickness swilling and water absorption) properties increases significantly but mechanical (bending and module of elasticity) properties increase up to 3 percent but after that gradually decreases. Also with incorporation of MAPP physical and mechanical properties of this nanocomposites improved and this positive effect was stronger for 5 percent MAPP than 3 one.
Tensile Properties and Microstructural Evolution of Friction Stir Processed Extruded AZ31B Alloy
Authors: Babu S. Ramesh , Kumar V.S. Senthil , Balasubramanian V. , Reddy G. Madhusudhan
Published: October 2011

Friction stir processing (FSP) is an emerging surface modification technology for enhancing the sheet metal properties through microstructural refinement at a particular region which might undergo severe plastic deformation. The extruded AZ31B magnesium alloy used in this investigation exhibits very limited ductility accompanied by brittle like behavior at room temperature because of hexagonal packed structure and severe mechanical twinning. Hence, an attempt was made to study the effect of processing parameters such as tool rotational speed and tool traversing speed on tensile properties of friction stir processed AZ31B magnesium alloy. It is found that the friction stir processing of the Magnesium alloy improved the ductility of the material when compared to the base material and also produced an ultrafine equiaxed grain in the processed zone, an ideal condition for the material to exhibit superplasticity.
Analyzing Oscillating Input Flow around a Circular Cylinder
Authors: Dehkordi Behzad Ghadiri , Mehrabadir Ali
Published: October 2011

2D fluid flow around a circular cylinder is numerically studied where the input flow is oscillating at different values of forcing frequency. The input section of domain has constant horizontal velocity except a region in the middle of this section which has an oscillating transverse velocity. The uniform fluid flow around an oscillating circular cylinder is also studied. The results are obtained for these two cases and compared with other experimental and numerical results. A comparison of the numerical results with the experimental data indicates that the 2D simulation has excellent agreement with literature. The effect of oscillation on the flow field, wake pattern and drag coefficient has been studied. The results show that the lift coefficient diagram is pure sinusoidal for forcing frequency f=0.85 and is lied in the lock-in zone. The mean drag coefficient has a maximum value in this forcing frequency.
The Combine Effect of Copper and Nickel on Tensile Strength of Ductile Iron
Authors: Sheikh M. Ashraf
Published: October 2011

The present study investigated the effect of copper and nickel together on ductile iron. Ductile iron was produced by the sandwich method using induction furnace installed at local commercial foundry. Heats without copper & nickel and with copper 0.5 wt% and 1.0 wt% nickel in combination were made. Tensile samples were machined from Y Block castings. Tensile test was performed to find out the effect of copper and nickel together on tensile strength of ductile iron. Effect of austempering heat treatment was also studied to find out the effect of copper and nickel in combination on tensile strength. The samples were austenitized at 900 oC for one hour and austempered at 270 oC and 370 oC. It was found that with the addition of copper and nickel the tensile strength of ductile iron increased. The tensile strength was more than double when the samples were subjected to austempering heat treatment at 270°C.
A Genetic Approach for Optimization Design of Gear System in Co-Rotating Twin Screw Extruder
Authors: Wen Wei Gang , Jia Hui Juan
Published: October 2011

According to the structure features of gear system in co-rotating twin screw extruder, the model of the gear system is built, and multi-objective optimization genetic approach based on the Pareto-rank is proposed to optimize the parameters of the gear system. The advanced optimal design method for the gear unit in co-rotating twin screw extruder is studied. A typical gear system in co-rotating twin screw extruder is designed, and the results show that the gear system meets the requirements in all aspects. This design method of the gear system is synthetic optimization for the gear system in co-rotating twin screw extruder.
Analysis of Smoke Agglomeration and Droplet Breakup in SRM
Authors: Liu Cong Lin , Gao Ye , He Zheng
Published: October 2011

Modern solid-propellant rocket motors (SRM) are laden with aluminum powder to increase the specific impulse. In SRM chamber, on the one hand, aluminum droplets evaporate and burn to form alumina smoke, on the other hand, the alumina smoke agglomerates to droplets as droplets collide with each other. The agglomeration model is employed to simulate the burning droplets. And breakup model also used. To avoid complex reaction theory, the article solves the mass, momentum and heat equations of disperse and continuity phases to simulate the chemic reaction. Results showed that burning efficiency and agglomeration of droplet varied by different initial diameters, and the temperature as well as smoke concentration also changed, especially in nozzle inlet.
Simulations of the FORMOSAT-5 Cold Gas Propulsion System by Using the Hybrid Continuum-Particle Method
Authors: Tseng K.C. , Lian Y.Y. , Chen Y.S. , Kuo T.C. , Gu B.R. , Wu J.S.
Published: October 2011

Reaction control subsystem (RCS) is an onboard satellite propulsion system used to provide required thrusting for orbit raising, orbit maintenance, and attitude control etc.. High pressure flow with high temperature could be generated in a chamber by chemical reactions or other power resources then expelled through a convergent-divergent nozzle to obtain thrust. In order to optimize the thrusting performance, numerical simulation is an efficient method to study the physics and parameters in design phase. In the current study, a hybrid method coupled continuum and particle methods is proposed to simulate flows involving continuum and rarefied regions. The Navier-Stokes (NS) solver named UNIC is developed by Chen and his coworkers. It employs the cell-centered finite-volume method with a hybrid 2D/3D unstructured-grid topology. The proposed particle code named Parallel DSMC Code (PDSC) is a parallelized solver based on the well-known Direct Simulation of Monte Carlo (DSMC) method, which was proposed by Bird in 1976. The physical domain is decomposed into several regimes and each sub-domain executes the serial DSMC code at different processor for speeding up the computing. A practical cold gas thruster with different chamber pressures is simulated by using this hybrid code to study the potential malfunction of the pressure regulator. Then the curve-fitting thrusting equation can be referred to satellite control operations.
Thermodynamic Analysis of Hydrogen Production from Ethanol in Supercritical Water Oxidation
Authors: Srisiriwat Nawadee
Published: October 2011

A thermodynamic analysis was performed for hydrogen production from ethanol reforming and oxidation in supercritical water (SCW) conditions. The minimization of Gibbs free energy was used to calculate the equilibrium composition to investigate the effect of operating conditions, pressure, temperature, H2O2:EtOH molar ratio and H2O:EtOH molar ratio, on product yields. The theoretical results indicated that the yields of hydrogen and carbon monoxide decreased as the pressure increased but a H2/CO ratio at atmospheric pressure was lower than that at SCW conditions. High temperatures increased the efficiency of hydrogen production although the amount of carbon monoxide also increased. The presence of oxygen led to great decreases in methane oxidized to carbon dioxide and water. The spending of some hydrogen oxidized to water resulting in a lower hydrogen yield. High H2O:EtOH ratios increased the yields of hydrogen and carbon dioxide but decreased the methane and carbon monoxide production. It is possible to conclude that high temperature, high H2O:EtOH ratio and low addition of oxygen should lead to best results in the SCWO of ethanol.
Methods for Creating Uniform Irradiance for LED Luminaries with the Use of Reflectors
Authors: Chu Shao Shu , Hsu Jung Chang , Sevilla Christopher Miguel , Chiang Chun Huang
Published: October 2011

In the recent development of LED technologies and market growth of LED luminaries, further study is needed in order for LEDs to replace the current incandescent bulb. Because of the LED radiation pattern, and it being a point-type light source, LED luminaries must employ similar and different methods than those of other luminaries in order to achieve a uniform irradiance. The methods presented in this paper can fasten the production of luminaries while cutting cost and still make luminaries with over 80% uniform irradiance. To achieve these methods reflectors, of 97% reflectivity, of multiple shapes and angles are combined with different arrays of LEDs. All luminaries are constructed using SolidWorks, and then ray data is simulated in TracePro commercial software. The final luminaries are then manufactured and the simulated results are compared and verified with experimental results. The purpose of this paper is to create luminaries for different situations that are affordable to produce while maximizing light efficiency.
A New Optical Technique for Surface Roughness Measurement of Tio2 Thin Films
Authors: Kuo Chil Chyuan , Chen Yi Ruei
Published: October 2011

A rapid optical inspection system for rapid measuring the surface roughness of titanium dioxide (TiO2) thin films is developed in this work. The incident angle of 60° is a good candidate for measuring surface roughness of TiO2 thin films and y = 90.391x + 0.5123 is a trend equation for predicting the surface roughness of TiO2 thin films. Roughness average (Ra) of TiO2 thin films (y) can be directly deduced from the peak power density (x) using the optical inspection system developed. The results were verified by white-light interferometer. The best measurement error rate of the optical inspection system developed can be controlled about 8.8%.The saving in inspection time of the surface roughness of TiO2 thin films is up to 83%.
Calculation of Viscosity Coefficient of Moderately Dense Fluids from the Modified SAFT-BACK Equation of State
Authors: Maghari Ali , Pourasad Saeed
Published: October 2011

The viscosity of some simple fluids in the wide density and temperature ranges have been calculated by the modified Enskog theory (MET) and with the help of Kaplun equations. The thermal pressure, second virial coefficient and internal energy are calculated from the modified SAFT-BACK EOS. The proposed scheme was further examined for the prediction of the viscosity of some dense fluids, including Ar, N2, O2, CO2, CH4, C2H6, C3H8 and C4H10. A comparison of the calculated and experimental values of the viscosity yields an overall average deviation of 2.16%.
The Processing Method and Discuss of Curved Surface Based on Spatial Linkage Mechanism
Authors: Xiao Li Ping , Wei Wen Jun
Published: October 2011

Compared with the free surface, the ruled surface is a linear set of parameters, and is obtained by a straight line moving in space along the curve trajectory, and tts modern processing methods are all complex and high cost. Spatial linkage mechanism has many features such as simple structure, easily control, sports continuous and so on, and the initiative crank continuous rotating drives the mechanism, at the same time, the rod length, the motion pair length or the twist angle is changed, which the cutter with start position fixed on a point of the rod main moves along the given curve, and feed moves straightly along the rod itself, so, the ruled surface was processed. The method is uncomplicated, and achieves high efficiency and high precision continuous line contact surface parts finishing, operating easily and saving cost.
Find the Optimum Shape Design of Externally Pressurized Torispherical Dome Ends Based on Buckling Pressure by Using Imperialist Competitive Algorithm and Genetic Algorithm
Authors: Abdi Behzad , Mozafari Hamid , Amran Ayob
Published: October 2011

In this paper, we used the Imperialist Competitive Algorithm (ICA) and Genetic Algorithm (GA) to find the minimum weight design of torispherical dome ends under external pressure load. According to fabrication and strength of material requirements, a group of compromised counters are selected and studied. Based on ASME Section VIII and BS5500 pressure vessel codes, a reasonable buckling pressure limit is proposed. Four-centered ellipse method is quite effective in designing and constructing the dome structure and it is used here to construct the torispherical dome ends. Two different size torispherical dome end models are selected and studied. Imperialist competitive algorithm is found to be very efficient and easy to use for the applications.
Study on the Effects of Deformation Temperature on Microstructure and Mechanical Properties of AZ80 Magnesium Alloy
Authors: Li Xu Bin , Zhang Zhi Min
Published: October 2011

The effects of deformation temperature on microstructure and mechanical properties of AZ80 magnesium alloy were investigated. The mechanical properties and microstructure were carried out in Gleeble-1500 thermal simulation experiment and optical microscope. The extrusion deformation, dynamic recrystallization had taken place in all the deformation samples, grains were thinner than before deformation.The reasonable deformation process can make the dynamic recrystallization organization of grain smaller and obtain higher strength. The best deformation temperature was about 360°C to 390 °C.
Physical Properties of Thermoplastic Cassava Starches Extruded from Commercial Modified Derivatives in a Pilot Scale
Authors: Thongtan Roung Rong , Sriroth Klana Rong
Published: October 2011

Properties of thermoplastic starch (TPS) produced from commercial-grade modified cassava starches were investigated in a pilot scale for future practical production in plastic industry. Five types of commercial cassava starches including native, oxidized, acetylated, octenyl succinate and pregelatinized starches were transformed into TPS by extrusion. The morphology implied that degree of destructuration could be manipulated by adjusting amount of glycerol of the starch melt. All types of TPS exhibited strong water sensitivity especially when exposed to humid atmosphere (>0.75 water activity). Compared among these selected five commercial cassava starches, there were no significant differences in sorption properties. Tensile strength of the thermoplastic starches increased with increasing starch content, and a drastic gain was recorded for 80% starch content for all types of starches. The elongation at break seemed to reach a maximum value for native TPS and pregelatinized TPS when composition of starch was 70%. The concavity of elongation at break of both TPS’s could arise from greater mobility of starch molecules during deformation due to the presence of glycerol and water, so that the properties shifted from glassy to more fluid-like. When compared among the types of modification, pregelatinized starch produced a highly elongated TPS with lowest strength due to its complete destructuration of starch granules, and the octenyl succinate starch yielded the highest strength and most brittle TPS. This study proved that cassava starch had a considerable potential to further developed for biodegradable applications but higher degree of modification than these of common commercial grade was required to improve water resistance of its thermoplastic starch.