bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational Calculation of Thermal Efficiency in a Space Radiating Fin for Tow Different Materials
Authors: Kamrava Mohammad Hadi , Bazdidi-Tehrani Farzad
Published: October 2011

In all industries which are related to heat, suitable thermal ranges are defined for each device to operate well. Consideration of these limits requires a thermal control unit beside the main system. The Satellite Thermal Control Unit (STCU) exploits from different methods and facilities individually or mixed. The space radiating fin which is combined with a heat pipe can be used to transfer the excess heat from the satellite to outer free space. The finite volume method is employed to simulate numerically the temperature distribution in a space radiating fin and evaluate thermal fin efficiency. Final results are achieved for two different materials (Aluminum and Beryllium) and compared to each other. The present results are compared with the other analytical methods and good agreement is shown.
Progress on Reflective Terahertz Imaging for Identification of Water in Flow Channels of PEM Fuel Cells
Authors: Buaphad P. , Thamboon P. , Tengsirivattana C. , Saisut J. , Kusoljariyakul K. , Rhodes M.W. , Thongbai C.
Published: October 2011

This work reports an application of reflective terahertz (THz) imaging for identification of water distribution in the proton exchange membrane (PEM) fuel cell. The THz radiation generated from relativistic femtosecond electron bunches is employed as a high intensity source. The PEM fuel cell is designed specifically for the measurement allowing THz radiation to access the flow field region. The THz image is constructed from reflected radiation revealing absorptive area of water presence. The technique is proved to be a promising tool for studying water management in the PEM fuel cell. Detailed experimental setup and results will be described.
Study of Development Status and Future Development Proposals for Pulse Soild Rocket Motor
Authors: Wang Chun Guang , Liu Hong Chao , Yang De Min , Chen Cong
Published: October 2011

To speed the domestic research on double pulse motor,and specify the research direction,analyzed the pulse separation device (PSD) of external double pulse motors,classified them according to certain characteristics,expounded research status of domestic double pulse motor,pointed out problems in the study.With the future needs of the missile force,proposed suggestions of future development for domestic research on double pulse motor,and specified the research direction of it.
Determination of Flow Characteristics and Turbulent Heat Transfer in a Ribbed Roughened Square Duct, Part 1: Turbulence Models
Authors: Etminan Amin , Jafarizadeh H. , Moosavi M. , Akramian K.
Published: October 2011

Nowadays, many researchers works in fluid dynamics has been concentrated on determine the suitable turbulent model for better describing the flow structure and heat transfer characteristics in a specific problem, there are a lot of cases which are necessary about designation of an optimized turbulent model. In the present work, a ribbed roughened square duct has been investigated numerically. A two-dimensionally study has been done to evaluate the flow structure, heat transfer and computational efforts of seven turbulent RANS models, contemporaneously. In the Part 1 of this study turbulence models, which are used in these type of problems has been investigated. In the next, advantages of introduced turbulence models has been present and explained. The results of numerical simulations will be presented in the Part 2.
Dynamic Parameter Identification Using Ambient Response Analysis and Ibrahim Time Domain Approach: A Case Study on a Steel Plate Structure
Authors: Anuar M.A. , Roslan Liyana , Mat Isa A.A.
Published: October 2011

Since the level of vibration always depends on the natural frequencies of the system, it is important to know the modal parameters of such system to control failure and provide prevention actions. However, for many mechanical engineering machines or structures, there is a demand and necessity to determine real-life modal parameters using actual operating condition. This type of testing condition cannot be done in lab environment because most of the mechanical structure is big in size and heavy. Thus, the purpose of this paper is to study the natural frequencies of a steel plate by using Operational Modal Analysis (OMA) and Ibrahim Time Domain (ITD). Comparison of results between both approaches will be shown.
Analytical Study on Wear Interaction between Rail-Wheel
Authors: Windarta Windarta , Bin Sudin M.
Published: October 2011

The interaction between wheel-rail produced defects on each other. Many studies of wear were done using pin-on-disc tribometer on interaction between the wheels – rail. The present paper proposes analytical study on wear. Wear rates were determined using depth of wear prediction on the interaction surfaces between wheel-rail. This prediction has been validated using pin-on-disc experimental technique using normal load of 100 N. The results show that the predictive equation developed can be used to predict the actual wear rate.
Modeling and Analysis for Powertrain Dynamics of Electric Vehicle Systems
Authors: Park Gwangmin , Lee Seonghun , Jin Sung Ho , Kwak Sangshin
Published: October 2011

This paper provides presents the dynamic analysis and computer simulation results of electric vehicle (EV) powertrain performance systems. The generic simulation platform of an electric vehicle is developed using based on the SimPowerSystems/SimDriveline of MATLAB. Individual components of the model are constructed based on real vehicle data and mathematical dynamic model equations. The analytic results obtained from the mathematical modeling are verified with electric vehicle dynamics using generic simulation platform.
Finite Element Stress Analysis of Optical Fiber due to Mechanical Expansion of Hydrogel Coating
Authors: Yulianti Ian , Sahmah M. Supa’at Abu , Idrus Sevia M. , Kurdi Ojo , Ridwanto S. Anwar M.
Published: October 2011

This paper presents the stress analysis in optical fiber due to swelling of hydrogel material coated on it. The silica optical fiber was assumed to be coated by hydrogel that consists of hydroxyethyl methacrylate, acrylic acid and ethylene glycol dimethacrylate as crosslinker. The hydrogel swelling was modeled using free energy function. The conditional equilibrium of hydrogel was solved using finite element method and the stress induced in optical fiber was simulated simultaneously. The simulations were done for two hydrogel coating thickness values, 30 µm and 40 µm. Etched optical fiber coated by 40 µm hydrogel was also simulated. The results show that maximum stress in optical fiber is higher for thicker hydrogel thickness and is higher for etched optical fiber. Maximum stress magnitudes at all pH values are below tensile strength of optical fiber.
Implementation of New Fission Barrier Model in TALYS Code
Authors: Perkasa Yudha Satya , Waris Abdul , Kurniadi Rizal , Zaki Su'ud
Published: October 2011

This paper is aimed to calculate neutron induced fission cross section using TALYS nuclear reaction code by utilizing new fission barrier model parameter. The new fission barrier model is based on minimization method of action functional of deformed nucleus fission trajectory in configuration of space from ground state to the exit barrier. New fission barrier parameter that obtained from this new model will be fed into the TALYS code to calculate the fission cross section of Th-232 and U-238 through statistical method. The result shows a better agreement with ENDF data compared to that of ETFSI (Extended Thomas-Fermi and Strutinsky Integral) or Mamdouh model of fission barrier for energy between 2 and 10 MeV.
Development of Object-Oriented Direct Simulation Monte Carlo Code for Modeling of Rarefied Flow around Geometries of Arbitrary Shapes
Authors: Jain Sourabh , Ramachandran Prabhu
Published: October 2011

Rarefied flows cannot be accurately simulated using Navier-Stokes (N-S) equations. The Direct Simulation Monte-Carlo (DSMC) technique is a particle based method for accurate simulation of flows under such conditions. A DSMC code is developed using an object-oriented (OO) approach which can simulate flows around arbitrary shapes. Hence, the flux from such boundaries can be correctly predicted. The object-oriented approach enables for easy modification of the code. For example, it is easy to use different collision models to implement different relaxation algorithm. The code is validated for the one-dimensional Fourier heat conduction problem. Results for the development of a shock due to supersonic flow over a 15 degree wedge are also presented. Inclined boundary of the wedge is correctly captured as the particles interact with the the exact shape of the boundary. Shock angle is found more than expected due to rarefaction effects.
Modeling and Analysis of the Grinding Parameters
Authors: Shinde Priya S.
Published: October 2011

Efficient grinding of structural ceramics requires judicious selection of operating parameters to maximize removal rate while controlling surface integrity. Grinding of ceramics is difficult because of its low fracture toughness, making it very sensitive to cracking. In the present work, experiments were carried out to study the effect of wheel parameters such as grain size and grinding parameters like depth of cut and feed rate on the surface roughness and surface damage. The significance of the grinding parameters on the selected responses is evaluated using analysis of variance. Mathematical statistics like “Minitab” is used to analyzed the grinding conditions for maximum material removal, using a multi-objective function model, by imposing surface roughness, surface force and surface damage constraints. The choice of including manufacturer & apposes constraints on the basis of functional requirements of the component for maximizing the production rate is also embedded in the Mathematical statistics. For the verification of present work, the Mathematical statistics results are compared with experimental work.
Gear Fault Identification Using Artificial Neural Network and Adaptive Neuro-Fuzzy Inference System
Authors: Soleimani Ali
Published: October 2011

This study compares the performance of gear fault detection using Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference System (ANFIS). The feature vector is extracted from vibration signals by standard deviation of wavelet packet coefficients at the fourth level. An improved distance evaluation technique is proposed for feature selection, and with it, the four salient features are selected from the original feature set. These features are normalized in the range zero to one and then fed into ANN and ANFIS. The gear conditions were considered to be healthy gearbox, slightly worn, and medium worn and broken-teeth gears faults. The output layer of ANN and ANFIS consists of one node indicating the status of the gearbox by four labels. A 3-layer Multi-Layer Perceptron (MLP) neural-network and an ANFIS were designed to carry out the task. The results show that the classification accuracy of ANFIS is better than MLP. Also, the effectiveness of the proposed feature selection method is demonstrated by the test results.
Orthogonal Test Design and Numerical Simulation of 100QJ10 Type Deep-Well Pump
Authors: Zhou Ling , Shi Wei Dong , Lu Wei Gang
Published: October 2011

In this paper in order to develop high efficiency and high head deep-well pump, a L9 (34) orthogonal experiment was performed with four factors and three values including outlet angle, outlet width, the outside diameter of impeller back shroud, etc. 9 impellers were designed. The whole flow field of new-type two-stage deep-well pump at the operating point for design was simulated by FLUENT 6.2 using the standard model, SIMPLEC algorithm, second-order upwind scheme to solve, and analyze the independent of the number of the grid. 9 groups of the efficiency and head in design scheme were obtained. The effects of geometrical parameters on efficiency, head were researched using Latin square test method. The primary and secondary factors of the design parameters were acquired by way of variance analysis. According to the test result, an optimum program to further design was put forward. After manufactured and tested, the efficiency and head of the final optimal design models were significantly improved. The productions show good energy saving and material saving characters and could replace traditional pumps for deep well in the future, the comprehensive technical indicators achieve international advanced levels. The results would be instructive to the design method of new-type deep well pump.
Numerical Modeling and Design of Thermoelectric Cooling Systems
Authors: Jou Rong Yuan
Published: October 2011

Thermoelectric coolers are often used as reliable energy converters in a large range of applications. For design considerations, it is crucial to establish an effective methodology to determine and optimize the TEC performance within the cooling system constraints. For this purpose, firstly, three approaches are used to obtain the internal parameters of a given thermoelectric module. For these three estimating procedures, the simulated pumping powers are in the sequence of method III < method II < method I for each temperature difference. Hence, good precision of the simulated data are obtained by averaging the results of these three methods. Then, design optimizations of a thermoelectric assembly are conducted to obtain the device parameter, efficiency, and maximum power, respectively. Results show it is simple and effective way for design of a thermoelectric cooling system.
Modeling and Control of Ultra Precision Positioning System for a Grating Ruling Machine
Authors: Shen Yuan , Liu Dong Cai , Lian Guo Fu , Guo Jie , Zhu Chan Gan
Published: October 2011

This paper presents a system modeling based control scheme of an ultra precision positioning system for a grating ruling machine. Since the positioning system having a long stroke with ultra precision, the positioning system consists of a coarse positioning stage driven by a servo motor and a fine positioning stage driven by a piezoelectric ceramic. In order to improve positional accuracy and remove the noise components of motion, a hybrid control scheme based on the system modeling is implemented. Considering position-dependent and time-dependent behaviors of the stages, a model based LQ controller is utilized to the coarse stage and a PID feedback controller based on neural network is utilized to the fine stage. Experiment results reveal the efficient and robust of the control scheme and show that the positional accuracy has been readily achieved within 8.6 nm.
A Bayesian Method for Model Optimization in Structural Equation Models with Mixed Continuous and Ordered Categorical Data
Authors: Li Yun Xian
Published: October 2011

In this paper, a Bayesian criterion-based method called the Lv measure, as well as its calibration distribution, is introduced and applied to model optimization of structural equation models with mixed continuous and categorical data. A simulation study is presented to illustrate the satisfactory performance of the Lv measure in model optimization.
Optimization of Highly Non-Linear Simulation Functions Using Improved Adaptive Response Surface Methodology
Authors: Manesh Mojdeh Shirazi , Motavallian Seyed Mohammadali , Fattahi Parviz
Published: October 2011

Adaptive Response Surface Methodology (ARSM) is a new developed method sequentially estimates the optimum of a complex function in a gradually reduced design space. In this paper, previously developed approach in ARSM has been compare and contrast with a new approach proposed by authors: using inherited Latin Hypercube Design (LHD) points and generating new Maximin LHD points by solving facility location problems in each iteration. Minimum of the response surface which is a second order approximate model based on LHD points in each iteration is an estimation of the real optimum of the complex function. The computation results reveal that the new suggested approach demonstrate more precise estimation of minimum with less number of function calls compare to the ARSM with random LHDs which is an improvement in the efficiency and accuracy of ARSM.
Three Dimension Finite Element Model for Neck-Spinning Process of Tube at Elevated Temperature
Authors: Huang Ching Hua , Hung Ching Hua , Hung Jung Chung , Lin Chia Rung
Published: October 2011

The aim of this research is to investigate numerically the neck-spinning process of a tube at elevated temperature. The commercial software Abaqus/Explicit was adopted in the simulation. For the construction of the material model, special uni-axial tensile tests were conducted at elevated temperature and various strain rates, since the material is sensitive to strain rates at high temperature. The influence of the element type and mass scaling factor were investigated through numerical simulation. Full-integration shell element is the better choice in the simulation of the neck-spinning process at elevated temperature. The use of suitable mass scaling factor will make the analysis more efficiency. Comparisons between experimental and simulation results on thickness distribution and the outer contour of the spun tube are discussed. Good agreement was found between experimental and simulation results.
Forming Force Analysis in Fine-Blanking Process by Experimental Approach and Analytical Formulation
Authors: Daiezadeh Vahid , Elyasi Majid , Mollaei Meghdad
Published: October 2011

Large deformation is a major deformation operation in many metal-forming processes, such as forging, rolling, extrusion, stamping and fine-blanking. It is difficult to study the deformation changes in these processes in a practical way, through the measurement of forces, due to the severe and localized nature of plastic deformation such as in the fine-blanking operation. Therefore, the forces analysis of most metal-forming processes cannot be carried out successfully by experiments. Thus, this paper aims to present the development of an effective process of forces measurement in fine-blanking process. Also, the effect of blank geometry and material properties on forming force in fine-blanking process was studied by theoretical formulation and experimental approach. Tensile strength and initial blank thickness were considered in this research. The obtained results indicated that by increasing the initial blank thickness and the tensile strength, the forces in fine-blanking process is increased.
Thermal and Coolant Flow Computational Analysis of Cooling Channels for an Air-Cooled PEM Fuel Cell
Authors: Mohamed W.A.N. W. , Remeli M.F. , Hamid A.H.A. , Atan R.
Published: October 2011

Polymer Electrolyte Membrane (PEM) fuel cells are clean electrical power generators for applications normally up to 100 kW power requirements. It has the advantage of fast start-up due to its low operating temperatures of 60oC to 100oC. However, the low temperature requirement has to be addressed with an efficient thermal management system. For an air-cooled PEM fuel cell, cooling channels with a straight rectangular configuration are widely applied. This work establishes a computational methodology for the analysis of coolant flow mechanics related to the channel geometry for a specific bipolar plate size. The velocity and thermal gradient, average velocity rise factor (AVRF) and total cooling rates were determined from Computational Fluid Dynamics simulation based on initial coolant Reynolds number of approximately 250 to 750 with a steady heat flow of 82W. All geometries showed nearly 100% cooling capability respective to the heat load, but differ in the aspects of average plate temperature achieved, its temperature profile as well as existing gradient. From the analytical perspective of thermo fluids engineering, the selection criteria of suitable micro cooling channel configurations, depending on operating priority, was established.
Numerical Simulation of Cavitation and Aeration in Discharge Gated Tunnel of a Dam Based on the VOF Method
Authors: Jalalabadi Razieh , Nouri Norouz Mohammad
Published: October 2011

Cavitation, usually known as a destructive phenomenon, involves turbulent unsteady two-phase flow. Having such features, cavitating flows have been turned to a challenging topic in numerical studies and many researches are being done for better understanding of bubbly flows and proposing solutions to reduce its consequent destructive effects. Aeration may be regarded as an effective protection against cavitation erosion in many hydraulic structures, like gated tunnels. The paper concerns numerical simulation of flow in discharge gated tunnel of a dam using RNG model coupled with the volume of fluid (VOF) method and the zone which is susceptible of cavitation inception in the tunnel is predicted. Then a vent is considered in the mentioned zone for aeration and the numerical simulation is done again to study the effects of aeration. The results show that aeration is an impressively useful method to exclude cavitation in mentioned tunnels.
Effect of Plasticizers on Ion Transport Properties of PEO+NH4PF6 Polymer Electrolyte System – Dielectric Studies
Authors: Mishra Kuldeep , Rai D.K.
Published: October 2011

Dielectric properties of proton conducting polymer electrolyte system, containing polyethylene oxide (PEO) as host polymer and ammonium hexfluorophosphate (NH4PF6) as complexing salt plasticized with EC and EC:PC, are investigated. The free standing films of thickness ~ 200 - 300µm are synthesized by solution casting technique. The electrical conductivity studies show that plasticization of the polymer electrolyte results into an enhancement in its conductivity by about two orders of magnitude. The maximum room temperature bulk conductivity is obtained to be ~ 10-5 S/cm for the plasticized polymer electrolyte. To understand the ion transport mechanism, different frequency dependent parameters are measured like dielectric permittivity, loss tangent and AC conductivity. The ionic transference number of the prepared systems is found to be close to unity which shows ion dominant charge transport in the electrolyte system. The conductivity of the polymer electrolyte has been found to be very sensitive to the relative humidity, which makes it a good candidate for its application for humidity sensor.
Mode Analysis of End-Milling Process by Recursive Least Square Algorithm
Authors: Kim Jong Do , Yoon Moon Chul
Published: October 2011

In this study, an analytical realization of end-milling system was introduced using recursive parametric modeling analysis. Also, the numerical mode analysis of end-milling system with different conditions was performed systematically. In this regard, a recursive least square (RLS) modeling algorithm and the natural mode for real part and imaginary one were discussed. This recursive approach (recursive least square method : RLSM) can be adopted for the on-line system identification and monitoring of an end-milling for this purpose. After experimental practice of the end-milling, the end-milling force was obtained and it was used for the calculation of FRF (Frequency response function) and mode analysis. Also the FRF was analyzed for the prediction of an end-milling system.
Analytical Solution for Centrifugal Force Effect in Functionally Graded Hollow Sphere
Authors: Jabbari Mohsen , Mohazzab Amir Hossein
Published: October 2011

This paper presents the effect of centrifugal load in functionally graded hollow sphere. Analytical solution for stresses is determined using the direct method and the power series method. The material stiffness varies continuously across the thickness direction according to the power law functions of radial directions. Increasing the angular velocity results in increasing the all above quantities. With increasing the power law indices the radial displacement, the shear and circumferential stresses due to centrifugal load all are decreased and the radial stress due to centrifugal load increased.
A Competition Chemostat with General Variable Yield and Growth Rates in the Presence of a Internal Inhibitor
Authors: Luo Jian Mei , Feng Yu Ming
Published: October 2011

This paper considered two organisms competing for a nutrient in the chemostat in the presence of an inhibitor, where the yields and growth rates are general increasing function of the nutrient concentration. The inhibitor is produced by one organisms and is lethal to the other organism. By the theory of qualitative analysis for ordinary equations, first, conditions of the existence and local stability of the rest points are obtain; then the global asymptotical stability, the existence of limit cycles and Hopf bifurcation are discussed.
Tip over Stability Analysis of a Three-Wheeled Mobile Robot Capable of Traversing Uneven Terrains without Slip
Authors: Appala Tharakeshwar , Ghosal Ashitava
Published: October 2011

A mobile robot traversing an uneven terrain can undergo tip over instability when one or more wheels of the mobile robot losses contact with the uneven terrain. In this paper, we study the tip over stability of a three wheeled mobile robot. The three wheeled mobile robot studied in this paper has torus shaped rear wheels and have the ability of lateral tilting – a condition required for slip free motion on uneven terrain. The torus shaped wheels and slip free motion makes the dynamics and tip over stability analysis more difficult and interesting. In this paper, the force-angle stability measure technique is used to analyze and detect tip over instability. Simulation results of the stability analysis shows that the wheeled mobile robot with lateral tilt of rear wheels is capable of moving on certain kinds of rough terrains without tip over.
Electron Spin in Quantum Hall Effect in AlxGa1-xas: D. C. Tsui's Data
Authors: Shrivastava Keshav N.
Published: October 2011

The Hall resistivity in the layers of AlxGa1-xAs/Al0.32Ga0.68As is found to show plateaus at certain fractions which depend on the effective charge. The Hall resistivity formula ρxy=h/e2 has been modified to ρxy=h/[(1/2) ge2] so that the effective charge of the electron becomes, e*=(1/2) ge. The plateaus occur at the effective charge determined by g = (2j+1)/(2l+1). Some of the plateaus are explained to arise from the g values while some others require the use of Landau levels. The flux quantization is modified to include the effect of spin. When the samples are doped with aluminium, the clusters of Al atoms occur in the GaAs resulting into electron clusters in which the spin is NS with S=1/2 and N=101. The electron clusters form a temperature dependent plateau in the Hall resistivity.
Feasibility Analysis of Gas Storage in JB Area Caprock Evaluation
Authors: Shi Lei , Gao Shu Sheng
Published: October 2011

Underground gas storages （UGS） are widely used to store the excess of produced natural gas during periods of low demand, and relieve the pressure during periods of high demand. Depleted natural gas reservoir is generally the best choice against others. Proper selection of a depleted gas reservoir is essential to the succession, steady and reliability of UGS in the long run. Sealing capacity of caprock is an important index for measuring the performance of gas storage reservoir. In order to analysis feasibility of UGS in JB area, the development characteristics of caprock were studied, the sealing gas effectiveness of caprock was evaluated. it was concluded that the main caprock was the formation of evaporative carbonate platform, and the breakthrough pressure of cap rock was high. The cap rocks with good sealing capacity were distributed in the area between S224 well and S39 well. The sealing ability was comprehensively evaluated by use of the development features and sealing capacity of caprock.
Condensate Migration Dynamics into Porous Bed in a Nonperforated Chamber
Authors: Siswanto Eko , Katsurayama Hiroshi , Katoh Yasuo
Published: October 2011

Due to complexity of condensate-migration into a porous-bed, the analytically simplified studies using uniform-flow assumption need enhancement through performing experiments. This study is conducted by maintaining saturated vapor-air over porous-alumina-balls and glass-beads-bed in a nonperforated chamber. Walls of the chamber are controlled isothermally. By evaluating on subcooling-, diffusive-, and porous perturbation-parameter, it is known that condensate migrates in Darcian regime. In this regime, based on visualized evidence and proposed Lyapunov-exponent-base series, this migration study finds that there are periodic- and unperiodic-dominant subregimes, where a temporal chaotic-migration case is found in the unperiodic-dominant subregime.
The Leveling Position Control of a Four-Axial Active Pneumatic Isolation System Using PWM-Driving Parallel Dual-On/Off Valves
Authors: Chiang Mao Hsiung , Lin Hao Ting
Published: October 2011

This study aims to develop a leveling position control of an active PWM-controlled pneumatic isolation table system. A novel concept using parallel dual-on/off valves with PWM control signals is implemented to realize active control and to improve the conventional pneumatic isolation table that supported by four pneumatic cushion isolators. In this study, the cushion isolators are not only passive vibration isolation devices, but also pneumatic actuators in active position control. Four independent closed-loop position feedback control system are designed and implemented for the four axial isolators. In this study, on/off valves are used, and PWM is realized by software. Therefore, additional hardware circuit is not required to implement PWM and not only cost down but also reach control precision of demand. In the controller design, the Fourier series-based adaptive sliding-mode controller with H∞ tracking performance is used to deal with the uncertainty and time-varying problems of pneumatic system. Finally, the experiments on the pneumatic isolation table system for synchronous position and trajectory tracking control, including no-load and loading conditions, and synchronous position control with master-slave method, are implemented in order to verify that the controller for each cushion isolator can realize good position and trajectory tracking performance.
Influence of Thermal Simulated and Real Tandem Submerged Arc Welding Process on the Microstructure and Mechanical Properties of the Coarse Grained Heat Affected Zone
Authors: Moeinifar Sadegh
Published: October 2011

The high-strength low-alloy microalloyed steel was procured as a hot rolled plate with accelerated cooling. The Gleeble thermal simulated process involved heating the steel specimens to the peak temperature of 1400 °C, with constant cooling rates of 3.75 °C/s and 2 °C/s to room temperature. The four-wire tandem submerged arc welding process, with different heat input, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat affected zone region for all the specimens along the prior-austenite grain boundaries and between bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat affected zone regions. The martensite/austenite constituents were obtained by a combination of field emission scanning electron microscopes and image analysis software The Charpy absorbed energy of specimens was assessed using Charpy impact testing at-50 °C. Brittle particles, such as martensite/austenite constituent along the grain boundaries, can make an easy path for crack propagation. Similar crack initiation sites and growth mechanism were investigated for specimens welded with different heat input values.
Preliminary Investigation on Atmospheric-Induced Stress Corrosion Cracking of British Intermediate Level Nuclear Waste Containers: Residual Stress Analysis and Four Point Bend Exposure Test
Authors: Janin Yin Jin , Lyon Stuart B. , Wintle John , Holmes Briony , Lee Chi Ming
Published: October 2011

There are approximately 45,000 Intermediate Level Nuclear Waste (ILW) containers currently stored in the UK at Sellafield and elsewhere. These stainless steels containers should last up to 150 years of surface storage. In this study the general structural integrity of 500L ILW containers were investigated. The associated degradation issue under ambient conditions known as atmospheric-induced stress corrosion cracking (AISCC) has been studied. Preliminary investigation included profiling of residual stress distribution in parent and weld specimens, atmospheric exposure testing under various salts. So far residual stress profile shows high degree of complexity. No cracks have been observed until this moment in time.
Robust Control of DC Motor Using Fuzzy Sliding Mode Control (FSMC)
Authors: Zare Assef , Moghaddas Mahboubeh , Dastranj Mohamad Reza , Changizi Nemat
Published: October 2011

Wide amplitude, DC motor's speed and their facile control cause its great application in industries. Generally the DC motors gain speed by armature voltage control or field control. The suggestion method in this paper is using sliding mode fuzzy control for DC motors robust control. The result is showing by use of this method we can't see any oscillation in responses and the time for reaching the normal speed is very short.
Study on Intersection Criterion of MEFP Warhead to Target
Authors: Yang Wei Ling , Jiang Chun Lan
Published: October 2011

Putting forward the straight-line trajectory of MEFP （multi-explosively formed penetrators, also called attack unit） in the target coordinate by means of building ground coordinate and target coordinate and the conversion of ground coordinate to target coordinate in the Area Blank off Weapon System. According to the intersection criterion that there are only two points between the attack unit straight-line trajectory and the cylindrical surface of the target, whether attack unit hits the target or not is decided. The intersection criterion is applied on the simulation of all kinds of different distributed plans.
Effect of Casting Design to Microstructure and Mechanical Properties of 1 mm TWDI Plate
Authors: Soedarsono Johny Wahyuadi , Sulamet-Ariobimo Rianti Dewi
Published: October 2011

In producing thin wall ductile iron (TWDI) cooling rate must be strictly maintaned to prevent carbide formation. There are many ways to control cooling rate and one of these is through casting design, especially gating system design. This paper discusses the possibility to produce 1 mm TWDI plate and also to note the effect of gating system design to microstructure and mechanical properties. Casting design based on gating system design are made to produce 1 mm TWDI plate. The 1 mm TWDI plates will be used for fin. There are three design and coded as T1, T2, and T3. The moulds used were made from furan sand. Beside the experiment, casting design simulation with Z-Cast was also conducted to ensure the completion of producing 1 mm TWDI plate. Simulation result showed that all designs could produce 1 mm TWDI plate. Result from experiment showed that all the designs have microstructure consisting of nodule graphite in ferrite matrix and carbide. Apart from mentioned microstructure there is also skin effect. The difference between all designs lies in carbide content and skin effect width. All the nodularity exceeded 80% and nodule count exceeded 1000 nodule/mm2. Brinell hardness number for all design exceeded minimal standard given by JIG G5502. As for UTS only T2 design can exceed the minimal standard. There is a contradictive result between experiment and simulation in cooling rate.
Force-Line Driving Model for Robot
Authors: Tang Gang , Mi Wei Jian , Chang Dao Fang , Wang Cheng Tao
Published: October 2011

To introduce a novel method of driving robot move. This method is to use the force-line model to drive the limbs of the robot inspired from the skeleton movement driven by muscle. A humanoid robot with the force-line model has been constructed. New software for muscle force estimation has been developed. The solution of the parameters which are the input of the software has been statement. Finally, the input parameters have been obtained by experiment and calculation. The humanoid robot can be driven to imitate human walking by the force which along the force-line. It will provide wide insight in developing new type robot for complex motion and applying the technology of force-line driving model in other filed.
Application of Roe’s Flux-Difference Splitting for Turbulent Reacting Flow with k-ε Turbulence Model
Authors: Shourehdeli Shaban Alyari , Mesbahi Mohammad Hossein
Published: October 2011

Flux-difference splitting procedure is developed for the hyperbolic part of the governing equations of turbulent reacting flow. As a primer computation of turbulent flame velocity in methanol mixtures for various turbulent kinetic energy is presented.
Optimum Size of a Ground-Based Cylindrical Liquid Storage Tank under Stability and Strength Constraints Using Imperialist Competitive Algorithm
Authors: Abdi Behzad , Mozafari Hamid , Amran Ayob , Kohandel Roya
Published: October 2011

Steel cylindrical tank is one of the most common forms of liquid storage vessels. In this study the Imperialist Competitive Algorithm (ICA) is used to find the optimum size of a ground based cylindrical liquid storage tank that is supported at both ends and the design considerations are stability and strength constraints. In this study total internal pressure and total special pressure are assumed as two types of load. The optimization procedure is formulated with the objective to minimize the mass of the tank due to the allowable capacity of cylindrical tank.
Macro Characteristics of the Spray from Intersecting Hole Nozzles
Authors: Leng Xian Yin , Qi Kun Peng , Long Wu Qiang , Wei Sheng Li
Published: October 2011

The formation method of the intersecting hole nozzle, each hole is formed by the converging of two or more child holes, is proposed, for the purpose of accelerating the fuel-air mixing process of direct injection internal combustion engines. In order to examine the macro characteristics of intersecting hole nozzles, three single-orifice intersecting hole nozzles, with the intersecting point of the axes of child holes locating inside, outside, and right at the exit surface, were manufactured. And high speed photography was employed to visualize, thus to quantify the angle and penetration of, the spray from these intersecting hole nozzles in a vessel under ambient room temperature and pressure of 0.1 to 2.0 MPa. The experimental results showed that the spray from intersecting hole nozzles were fan-shaped, which were beneficial for prompting the fuel-air mixing. Particularly, when the intersecting points of the axes of child holes locate right at the exit surface, the longest spray penetration was obtained, and the spray front angle is slightly smaller than side angle. While the intersecting points of the axes of child holes locate inside or outside the exit surface, the spray penetration is shorter, and the spray front angles are extremely larger than side angles under pressure of 0.1 to 2.0 MPa. With the rising of ambient pressure, the differences between front angle and side angle of all the three intersecting hole nozzles become smaller in different degrees.
CFD Simulation for a New Ducted-Fan UAV Configuration
Authors: Zamri Omar
Published: October 2011

Ducted-fan unmanned aerial vehicle (UAV) is very beneficial in many civil and military applications. It has a good operational flexibility similar to helicopter. Normally, the ducting of high speed spinning fan is done for several reasons; the duct produces lift, it provides higher static thrust when compared to a bare fan of the same diameter, substantial noise level from a spinning fan or rotor can be suppressed, and it increase the safety level for both of the system and the user. However, the main challenge is to understand the aerodynamic characteristic of this vehicle. In this paper, computational fluid dynamic (CFD) is used to study the airflow and aerodynamic characteristic on a new configuration of ducted-fan UAV.
A Simple Analytical Model to Simulate Oblique Ballistic Impact onto Fabric
Authors: Akbari Mohamad Ali , Liaghat Golam Hosein , Sabouri Hadi
Published: October 2011

A simple analytical model for oblique ballistic impact of projectiles into fabrics are presented. This model is extension of Chocron-Benloulo penetration model. Results are compared with experimental data. There is good agreement between analytical and experimental results.
Mass Transport in a Microchannel Bioreactor with a Porous Wall
Authors: Low Hong Tong , Chen Xiao Bing , Yu Peng , Winoto Sony
Published: October 2011

A two-dimensional flow model, incorporating mass transport, has been developed to simulate flow in a microchannel bioreactor with a porous wall. A two-domain method was implemented which was based on finite volume method. For the porous-fluid interface, a stress jump condition was used with continuity of normal stress; and the mass interfacial conditions were continuities of mass and mass flux. Two parameters are defined to characterize the mass transports in the fluid and porous regions. The porous Damkohler number is the ratio of consumption to diffusion of the substrates in the porous medium. The fluid Damkohler number is the ratio of substrate consumption in the porous medium to substrate convection in the fluid region. The concentration results are found to be well correlated by the use of a reaction-convection distance parameter which incorporates the effects of axial distance, substrate consumption and convection.
Effects of Cyclic Loading on Interface of Liner and Propellant
Authors: Qu Kai , Zhang Xu Dong , Zhang Jie
Published: October 2011

During the service life of a solid rocket motor, the interface of liner and propellant is subjected to cyclic loading. In order to find the damage law of it, fixed stress amplitude cyclic loading experiment was used. In the process of the experiment, constitutive behavior and dissipative energy mainly researched. The influence of the fixed stress amplitude on properties of liner/propellant was also studied. The results show that the remains strain increased following the increase of cyclic number. The dissipative energy of every cyclic loading is random, so it does not adapt to be damage variable. The stress amplitude and natural logarithm of the cycle number accord with exponent equation.
Pipe Displacement by High Order of Accuracy Method
Authors: Fathelrhman Omer , Li Bao Ren
Published: October 2011

A fluid-structure interaction (FSI) is the interaction of some movable or deformable structure with an internal or surrounding fluid flow. FSI is the essential consideration in the design of many engineering systems; e.g. aircrafts, nuclear and piping system. In this paper firstly the orders of accuracy of finite difference method were tested and secondly two types of algorithms were evaluated to obtain the displacement and transient pressure for pipe conveying fluid under transient condition, From the study it reveals that the fourth order of accuracy is the more compatible for this combination of equations. The transient pressure calculated by algorithm1 and algorithm2 were compared with experimental result to find that algorithm2 has a full agree with experimental data.
Experimental Investigations of Cutting Conditions Influence on Main Cutting Force and Surface Roughness Based on Chip Form Types in Cast Nylon Turning
Authors: Suksawat Bandit
Published: October 2011

This paper aims to investigate cutting conditions influence on main cutting force and surface roughness based on considered chip form types in cast nylon turning operation with single-point high speed steel cutting tool. The 75 experiments were performed by average of three levels of cutting speed, five levels of cutting depth and five levels of feed rate. The results reveal that main cutting forces were increased by an increasing of cutting speed and cutting depth for all obtained chip form types for all chip form types. The surface roughness is affected by increasing of feed rate and reduction of cutting speed for 2.3 Snarled and 4.3 Snarled chip form types. The statistical path-coefficient analysis results are shown that the main cutting force affected by cutting speed, depth of cut and feed rate with total causal effect value of 0.5537, 0.4785 and 0.1718, respectively. The surface roughness is influenced by feed rate, cutting speed and depth of cut with 0.8400, -0.2419 and-0.0711 of total causal effect value, respectively. These results are useful to perform varying cutting conditions for high quality of workpiece in cast nylon turning by control the chip form type.
Characteristics of Lean and Stoichiometric Combustion of Compressed Natural Gas in a Direct Injection Engine
Authors: Shahzad Raja , Naveenchandran P. , Rashid A. , Aziz Amir
Published: October 2011

This paper discusses the combustion characteristics of CNG under lean and stochiometric conditions in a direct injection engine. The experiments were carried out on a dedicated CNG-Direct Injection engine with 14:1 compression ratio. Combustion characteristics of CNG have been investigated on various injection timings. Injection timing of the fuel injection timing had significant effects on the engine performance, combustion and emissions. The effects became more significant when injection timing was retarded. Injection timing was set after the closing of intake valve and experiments are conducted at 0% and 50% load conditions. Lean stratified operation experiences faster combustion compared to that of stochiometric. In lean stratified operation, there were fast burn rates at the initial stage and slower burning at the later stage. Whereas in stochiometric conditions there is a slightly slower burn at the initial stage and a moderately faster burn at the later stage. The faster initial combustion in lean stratified operation might be due to rapid burn of the initial mixture due to higher turbulence, while a slower burn in the later stage due to diffusion. In contrary to that in stochiometric operations the initial burn is slightly slower, due to moderately strong turbulence and a faster burn due to moderately proceeding mixture. Thus the main effect of fuel injection timing can be explained by the fuel air mixing and the turbulence produced.
A Genetic Algorithm Approach for Multi-Product Multi-Machine CONWIP Production System
Authors: Ajorlou Saeede , Shams Issac , Aryanezhad Mirbahador G.
Published: October 2011

In this paper, a new mathematical programming model is developed to address common issues relating to single-stage CONstant-Work-In-Process based production lines. A Ge-netic Algorithm (GA) approach is then proposed to directly solve the model in order to simultaneously determines the optimal job sequence and WIP level. Unlike many existing approaches, which are based on deterministic search algorithms such as nonlinear programming and mixed integer programming, our proposed method does not rely on a linearized or simpliﬁed model of the system. results from a comprehensive numerical example indicate computational efﬁciency and validation of our method.
Analytical Solution of Electrokinetics Driven Flow in a Nanotube with Power Law Fluid by HPM
Authors: Ganji Davood D. , Gorji-Bandpy Mofid , Mostofi Mehdi
Published: October 2011

In this paper, Poisson-Boltzmann equation and Navier-Stokes equation will be solved by Homotopy Perturbation method (HPM). Working fluid in this paper is assumed to be non-Newtonian which follows power law model. Zeta potential that is used for the potential in near wall area of a tube will be small enough in order to use some simplifications. In this paper, Poisson-Boltzmann equation for a 30 nm diameter nanotube with large zeta potential has been solved by Homotopy Perturbation Method (HPM). According to the literature, results have been compared with numerical solutions and consistency of the results has been considered. Results show that HPM can approach to this problem reliably.