bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Power Flow Algorithm Incorporating Multi-Terminal VSC-HVDC
Authors: Ye Fang , Wei Zhi Nong , Sun Guo Qiang
Published: November 2011

Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) technology is a newly deve- loped power transmission technology. The basic principle and structure of multi-terminal VSC-HVDC is introduced and its steady-state mathematical model is set up. An improved power flow algorithm is deduced, which not only decouple the relationship between AC and DC systems’ variables in the strict mathematical form, but also can be integrated with the conventional power flow program and exhibit good accuracy and convergence characteristics compared to conventional technique. A numerical example of IEEE 14-bus test system with a 3-terminal VSC-HVDC network is given. The results show that the proposed steady-state model of multi-terminal VSC-HVDC and corresponding power flow algorithm are correct and effective.
Radial Laminated Magnetic-Barrier Rotor Optimization Design of Brushless Doubly-Fed Machine
Authors: Shangguan Ming Zhu , Liu Hui Juan , Zhang Qian
Published: November 2011

This paper establishes four kinds of Brushless Doubly-Fed Machine (BDFM) models with radial laminated magnetic-barrier rotor using ANSOFT finite element software, calculates the electromagnetic field of these four kinds of models, comparatively analyzes the magnetic field distribution, the torque capability, the end winding characteristics ,the rotor’s radial magnetic forces, the core losses and the motor operating performance of motor with different rotor structures, and thus provides theoretical guidance for optimization design of radial laminated magnetic-barrier rotor structure.
Numerical Simulation of Particle Axial Mixing in Rotary Kiln
Authors: Li Shao Hua , Zhang Xuan , Zhang Li Dong , Yu Kan Sheng , Hao Wan Jun
Published: November 2011

The discrete element code, EDEM, has been employed to simulate the axial mixing of size-binary particles in rotary kiln. Number of contacts has been introduced to track the progress of mixing and number of contacts between different particles has been took as mixing index between different particles to analyze the degree of mixing The results show that the larger velocity of particles in active layer is the main reason for the mixing; axial displacement of smaller particles is due to penetration of smaller particles through the intervals between larger particles.
Modeling of Electromagnetic Heating Systems
Authors: Gao Wei Jing , Li Li Zheng , Peng Wei Shao
Published: November 2011

Starting with the Maxwell equations, this article introduces the heating power as intermediate variable to modeling of electromagnetic heating system, and gets a non-linear model. Concludes that the ralationship between the heat power and the input current is nonlinear, the temperature and the heating power is the first order linear relationship. The model has importance significances for improving the stability and accuracy of the electromanetic heating system .
Analysis of Reactor Magnetic Circuit Based on ANSYS Command Flow
Authors: Yang Po , Yin Zhong Dong , Cui Ruo Chen , Kong Ning
Published: November 2011

Controllable reactor is the common equipment in the modern power system, which plays an important role in voltage control and reactive power compensation. The core structure of reactor effects the magnetic field distribution in the core and the loss of reactor. In this paper, the models of two kinds of classic reactors are built by the ANSYS command flow method, and explain the differences between magnetic valve controllable reactor and common reactor. This paper points out the advantages of command flow compared with the graphical user interface and the important role of ANSYS finite element analysis in the structural design of reactor.
Restrike Modeling of Vacuum Circuit Breaker Switching Off Shunt Capacitor Banks with EMTP
Authors: Wang Yong Yuan , Liu Sheng Hui , Liu Wen Ze , Wang Ke Ying
Published: November 2011

The shunt power capacitors are used as a reactive compensator while vacuum circuit breakers are used to switch shunt capacitors in power grid. To research the high over-voltage during switching off the shunt capacitors and a vacuum circuit beaker restriked, the restriking model is built with three-phase vacuum circuit breakers, considering the capacitors’ energy storage characteristic and asynchronous operating. The over-voltage is harmful to the insulation and life-circle of the equipments and even threatens power system safe and stabile operation. The variation trends of both recovery voltage between the contacts and the capacitors voltage are theoretically deduced. The model based on a 220kV substation of Guangdong grid was built and the most serious case that breakers are restriked in two phases are numbered with EMTP. Compared with theoretical results, simulation results are valid and practical.
Research on GMM Background Modeling and its Covariance Estimation
Authors: Zhang Yun Chu , Zhang Ru Min , Song Shi Jun
Published: November 2011

This paper analyzes the background modeling mechanism using Gaussian mixture model and the stability /plasticity dilemma in parameters estimation of GMM background model. To solve the slow convergence problem of Gaussian mean and covariance update formula given by Stauffer, a new updating strategy is proposed, which weighs the model adaptability and motion segmentation accuracy. Experiments show that the proposed algorithm improves the accuracy of modal learning and speed of covariance convergence.
A New Format Power Flow Computation Software Analysis and Design Based on MATLAB
Authors: Luo Jie , Wu Wen Hui
Published: November 2011

Power flow analysis plays a significant role in both design and operational stage. The purpose of any load flow analysis is to compute accurate steady state voltages and voltage angles of all buses in a network, the real and reactive power flows into every line and transformer, under the assumption of known generation and load. This paper focus on fast decoupled flow, a practical power system has been used as an example to introduce its application in actual calculation, what’s more, develops a fast decoupled load flow calculation program for n-node system by taking advantage of MATLAB. A visual GUI interface is also established with MATLAB. In addition, the paper proposes a new simple power system data format, different from the IEEE standard one. The correctness and simplicity of the proposed format is verified through IEEE-5bus,-9bus,-11bus,-39bus systems.
A New Method for Modeling of Fully Flexible Aircrafts
Authors: Guo Dong , Xu Min , Chen Shi Lu , Qian Yu
Published: November 2011

The purpose of this study is to produce a modeling capability for integrated flight dynamics of flexible aircraft that can better predict some of the complex behaviors in flight due to multi-physics coupling. Based on the studying of the exiting modeling approaches, the author put forward a new modeling method, and developed a new formulation integrating nonlinear rigid-body flight mechanics and linear aeroelastic dynamics for fully elastic aircrafts using Lagrangian mechanics. The new equations of motion overcome the disadvantages of the exiting methods, and include automatically all six rigid-body degrees of freedom and elastic information, the seamless integration is achieved by using the same reference frame and the same variables to describe the aircraft motions and the forces acting on it, including the aerodynamic forces. The formulation is modular in nature, in the sense that the structural model, the aerodynamic theory, and the controls method can be replaced by any other ones to better suit different types of aircraft.
Simulation for Expansion of Fabrication Hydraulic Torque Converter and Corresponding Experimental Investigation
Authors: Hui Ji Zhuang , Zou Ya Ke , Cao Jie , Liu Ze Feng
Published: November 2011

Under the operating load, the fabrication hydraulic torque converter could be regarded as a rotating pressure vessel. It will dilate like a balloon as a result of the centrifugal force and fluid pressure. The magnitude of deformation affects the performance of fabrication hydraulic torque converter and its connection with adjacent parts. Based on the three dimensional measuring machine and platform UG and Gambit, the frame model of ballooning deformation is established and simplified. Based on modern computational fluid dynamics theory, the simulation software FLUENT, MSC.Partran and MSC.Nastran are employed to make simulation prediction for the ballooning deformation. The results of the simulation are checked out through the experiments. The experimental results show that the calculation and experiment results are coherent. The increase of axial displacement has a linear relation with the rise of fluid pressure. The largest stress occurs near the intersect of the shell and working face. The largest strain takes place at the outlet of the pump and inlet of the turbine.
A Blackout Model Based on Optimal Risk Index and High-Risk Line Identification
Authors: Ding Xue Yang , Liu Xin Dong
Published: November 2011

This paper summarizes the defects of both OPA model and its improved models and then proposes a new model in order to simulate real power system roundly. There is an inner loop based on DC power flow optimization to minimize the change in generation or load shed and an outer loop based on the risk theory. In the outer loop, whether to improve the line capacity and how to improve are determined by risk index of line improvement (RILI) and line improvement degree function, respectively. A new prevention strategy against cascading failure is proposed by identifying the high-risk lines and determining optimal RILI which minimize line improvement cost and load loss. In the end, simulation based on 39-bus New England System reveals that new model is closer to real power system than the original one by comparing outage probability and load loss between the two models, and risk-based assessment interval and line improvement delay play important roles in prevention against power system outages, and improvement based on risk assessment can reduce outage probability to varying degrees, which illustrates the practical significance of optimal RILI.
Computational Model for Machine Vision Inspection Based on Vision Attention
Authors: Shi Jin Fang , Su Zhen Wei , Li Guo Hui
Published: November 2011

Human vision system exploits this fact by visual selective attention mechanisms towards important and informative regions. A computational model of combination both bottom-up and top-down simulating human vision system for machine vision inspection is proposed. In this model, top-down knowledge-based information is highlighted to integrate into bottom-up stimulus-based process of vision attention. The model is tested on inspecting contaminants in cotton images. Experiment result shows that the proposed model is feasible and effective in visual inspection. And it is available and quasi-equivalent to human vision attention.
Fuzzy Based Model Predictive Control for Uncertain Nonlinear System
Authors: Xu Li , Liu Fei
Published: November 2011

In this paper, a model predictive control (MPC) scheme is investigated for uncertain nonlinear system with time delay and input constraint. First, the Takagi-Sugeno (T-S) fuzzy model is used to approximate the dynamics of nonlinear processes and the parallel distributed compensation (PDC) controllers which are parameter dependent and mirror the structure of the T-S plant model are proposed. Then a novel feedback PDC predictive controller obtained from the linear matrix inequality (LMI) solutions which can guarantee the stability of the closed-loop overall fuzzy system is put forward. Finally, a numerical example is provided to demonstrate the effectiveness and feasibility of the proposed method.
Temperature Simulation on Rotor and Stator of Hydro-Generator
Authors: Zhang Qun Feng , Cui Hui Min , Yan Jin Li , Wang Min , Chen Zhi Xiang
Published: November 2011

Reynolds averaged Navier-Stokes (RANS) equations, energy equation and V2f turbulence model equations governing the flow field of the rotor frame, magnetic yoke and the pole, the stator were solved with finite volume method(FVM) based on unstructured mesh. The MRF(multiple implicit rotating frame) method was used to simulated the rotating motion of the rotor frame, magnetic yoke and the pole. The flow characteristic of different parts was analyzed. The influence of the gap size between insulating layer of bar core, the gap size between insulating layer of pole and coil to the temperature distributions on the solid parts was studied. The results show that the temperature on the windward of the pole is lower than the temperature on the leeward. With the gap size between the insulating layer of bar and core varying from 0.0mm to 0.3mm,the temperature of insulating layer of bar rise increases 9.2 degrees, So the gap size is important for the life of insulating layer. With the gap size between the insulating layer of pole and the coil varying from 0.25mm to 0.75mm, the temperature of coil increases 16.5 degrees. The results provide a reference for the rational design of the gap size.
Output Feedback Adaptive Maneuvering for Nonlinear MIMO Systems with High Frequency Gain Matrix Hurwitz
Authors: Zhou Ying , Zang Qiang
Published: November 2011

In this paper, the adaptive maneuvering control based on output feedback is studied for uncertain nonlinear multi-input multi-output (MIMO) systems. The high frequency gain matrix of the systems only needs to be Hurwitz, which relaxes the positive definite limitation in the existing results. Based on the backstepping approach with vector form, an output feedback adaptive maneuvering control scheme is proposed. The geometric and the dynamic tasks are solved meanwhile the global stability of the closed-loop systems is guaranteed through the proposed control scheme.
Application of Pressure-Rate Deconvolution to Well Test Interpretation of Low Permeability Reservoirs
Authors: Shen Ying Hao , He Shun Li , Zhang Hong Ling
Published: November 2011

Pressure-rate deconvolution method based on the newly robust solution algorithm is applied to low permeability reservoirs, and deconvolution codes were developed for the study based on Schreoter deconvolution algorithm in this paper. The application of this method in a low permeability oilfield shows that deconvolution can provide much more information than the conventional well test interpretation methods, and this deconvolution method can interpret the whole test sequence but doesn’t be limited in pressure build-up period. It is proved that the pressure-rate deconvolution algorithm works well in well test interpretation of low permeability reservoirs.
Numerical Aperture and Partial Coherence Optimization in Optical Li-Thography under Off-Axis Illumination
Authors: Guo Li Ping , Fu Sheng Gui , Liu Xiao Juan
Published: November 2011

Numerical aperture NA and partial coherence sigma optimization in optical lithography is investigated for 100 nm dense lines under annular illumination and quadrupole illumination. Depth of focus (DOF) is calculated at different NA and sigma settings using PROLITH software. Based on the calculations of DOF, the NA and sigma settings are optimized by finding the values to maximize the DOF. At the optimum NA and sigma settings for 100 nm dense lines, the imaging performance is analyzed for semi-dense and isolated lines.
Research on the Efficiency Evaluation Model of Fire Command Automation System
Authors: Zhang Li Min
Published: November 2011

Based on the early research of the efficiency evaluation index system of fire command automation system,combining the characteristics of fire command automation system of our country, elected AHP to identify multi-criteria comprehensive weighs of the third-grade indexes, and then constructed dual-binding evaluation model of grade and number.
A New Method for Faulted Line Identification in Neutral Non-Grounded Distribution Systems
Authors: Li Dan , Wang Fang Zong
Published: November 2011

It is well-known that, the identification of the single-phase to ground faulted line in neutral non-grounded distribution systems is a difficult problem, due to its very small faulted current. This paper proposes a new method for the solution of this problem. The principle of the proposed method is to convert the neutral non-grounded system into a neutral grounded system temporarily by using a triggered vacuum switch based controllable short-circuit equipment. By time-domain numerical simulation, the proposed method is evaluated, and the simulation results have shown the effectiveness of the proposed method.
Design of Li-Ion Batteries Equalization Module of Electric Vehicle
Authors: Li Zhong Xing , Yu Feng , Li Mei
Published: November 2011

Due to the limited life of series-connected battery stack suffered from the imbalanced charging-discharging operation, the equalization management module has become the key part of a battery management system. To minimize the adverse effects caused by the performance inconsistency between individual battery cells, a battery equalization management module based on the super-capacitors was designed in this study. This module separated the imbalance status into three types, applied different control strategy according to the status, and balanced every sub-group respectively. Simulation and experimental results showed that not only the module made the battery pack charge and discharge balanced, but also the efficiency of equalization was improved.
Study on Pilot Performance Model
Authors: Liu Wei , Liu Cheng Kun , Zhuang Da Min , Liu Zhong Qi , Yuan Xiu Gan
Published: November 2011

In order to evaluate pilot performance objectively, back propagation (BP) neural network model of 621423 form in topology with eye movement data was established. Data source of BP neural networks that came from former experiment and random interpolation was divided into training set and test set and normalized. Based on neural networks toolbox in Matlab, hidden layer nodes of BP networks were determined with empirical formula and experimental comparison ; BP algorithms in the toolbox were optimized; The training set data and test data were input into model for training and simulation; Pilot performance of the three skill levels was predicated and evaluated. The research shows that pilot performance can be accurately evaluated by setting up BP neural networks model with eye movement data and the evaluation method can provide a reference for flight training.
NURBS Interpolation Algorithm Based on Feedrate Sensitive Points Identification
Authors: Lin Feng
Published: November 2011

The Non-uniform rational B-spline (NURBS) is widely used in CAD/CAM/CNC. The NURBS interpolation is crucial for an advanced CNC system compatible with NURBS. Classic NURBS interpolation algorithms always do not well consider both the contour precision and feedrate smoothness. This paper proposes a NURBS interpolation algorithm based on the feedrate sensitive points identification. The feedrate sensitive points is found out according to the chord error which is relative to the feedrate passing this point. Furthermore, the feedrate profile is adaptively planned between two adjacent sensitive points according to the distance between them. The feedrate profile of the whole NURBS can be connected with these feedrate sections. A cubic NURBS curve is adopted to evaluate the interpolation algorithm. Simulation results show that the proposed interpolation algorithm is available with reference value for industrial application.
The Performance Assessment and Optimal Design of EWMA Charts Based on Average Product Length
Authors: Yu Wang Hai
Published: November 2011

ARL (Average Run Length) is used as a tool to measure the performance of control chart. But it isn’t very accurate. In this paper, a Markov chain method is proposed to calculate the APL (Average Product Length) of EWMA chart, and APL is used as a criterion of performance assessment to decide optimal design of this chart. By comparing with traditional EWMA design method, we can find that this method can detect little shifts in processes more quickly.
Finite Element Simulation on Temperature Field Couple under Contact Resistor Thermal and Friction Thermal in Friction and Wear
Authors: Dong Lin , Jiang Hui Ping , Wang He Shun
Published: November 2011

Based on finite element simulation, the temperature field model for the frictional pair of third rail and collector shoe under the coupling of contact resistor thermal and friction thermal was established. The method of coupling the two kinds of thermal was given in detail, the temperature field was calculated, and the maximum coupled temperature changing under different electric current, velocity, and displacement of the model was studied. The results show that the temperature raising effect of friction thermal and contact resistor thermal is different. In the process of mechanical friction without electric current, the highest temperature is in the contact center line, the temperature distribution expands around the contact zone in descending tendency. But in couple condition, the temperature distribution with electric current expands around the contact point in descending tendency. In the two conditions, the temperature gradients are all becoming smaller. The maximum coupled temperature increases with the increasing of the electric current, and decreases with the increasing of the velocity under the constant displacement and normal force. The maximum coupled temperature increases linearly with the increasing of displacement under constant electric current, velocity and normal force.
Simulation of Islanding Detection for Photovoltaic Grid-Connected Inverters Based on Positive Feedback Intermittent Frequency Drift
Authors: Ming Xiao Jun , Sheng Zhu Yong , Ying Xu Qi , Yun Wang Dong
Published: November 2011

Islanding detection is a absolutely necessary function for Photovoltaic Grid-Connected Inverters and it is very important to detect the islanding accurately and quickly with less adverse impact on power quality. This paper proposes a positive feedback intermittent active frequency drift method which can decrease the adverse impact of frequency disturbance effectively within the time restrict of islanding detection according to that of traditional islanding detection methods. The theoretical analysis and simulation results show that this algorithm which is simple, effective, fast and have less adverse impact on power quality and has certain application value.
Study on Voice Transmission System of the Optical Fiber for Tube Leakage Monitoring Installment in the Power Station Boile
Authors: Xu Yuan Zhe , Chen Hong Zhen , Ma Shu Jing , Zhao Chang Jun
Published: November 2011

The tube leakage in the large power station boiler is the main reason for unplanned outage of power units. So how to prevent and control the leakage accident has become an important part of ensuring the safe operation of power grid. Sound spectrum analysis is the most commonly used detection method. At the top of the boiler, the temperature is high, and sometimes the positive pressure produced inside the boiler will make ordinary audio sensors particularly easily damaged. This paper designs a system of high temperature resistance fiber optic audio sensor and acoustic resonator. It can determine the parameter of fiber optic audio sensor, and double the leakage noise signal through the design of acoustic resonators. According to the experimental test results and theory, this system can effectively test leakage signal inside the boiler tube, and provide a new idea for leakage detection.
A Flux Observer of Voltage-Current Model Based on PI Regulator
Authors: Fan Sheng Wen , Zhao Xin Yong , Li Zheng Xi , Zhang Hu
Published: November 2011

This paper proposes a flux observer of voltage-current model based on PI regulator .Flux estimator value of current model at low speed is convergent gradually, so we adopt the current model. On the basis of traditional voltage model, we adopt improved model which substitute pure integral part with first-order inertia part and a compensation part, and it can solve DC drift and initial value with this method. Two models can be switched smoothly without concussion by setting appropriate PI parameter. The performance of the model is investigated and verified experimentally.
Analyze of Vehicle Active Rollover Control on Air Spring
Authors: Xia Jing Jing , Hu Chen
Published: November 2011

Based on the working characteristics of air spring, vehicle active rollover control system is studied. First , vehicle rollover forecast algorithm is designed by using the vehicle rollover forecast technique TTR. Then vehicle active rollover control system is designed with air spring inflation/deflation characteristics. Simulation results show that the design of vehicle active rollover control system can predict rollover risk, achieve the timely warning of vehicle rollover, and can adjust the air spring stiffness timely, improve vehicle lateral stability, reduce vehicle rollover accident under the condition of rollover risk.
Model Reduction of a Two-Link Rigid-Flexible Manipulator Based on Spectral Approximation Method
Authors: Pan Yun , Deng H.
Published: November 2011

In this paper, the dynamic model of a two-link rigid-flexible manipulator was established by using the theory of Lagrange equation. Due to the model is a distributed-parameter system, we present a simple, efficient method for model reduction based on spectral approximation method such that a model-based scheme can be implemented. The method was illustrated by comparing with the simulation results of the reduced-order model and the virtual reduced model based on finite element method.
Optimizing Back Surface Field of Heterojunction Thin-Film Solar Cells by Numerical Simulation
Authors: Lu Gang , Zhang Lu
Published: November 2011

A new structure of amorphous/ polycrystalline silicon heterojunction solar cells is reported. For a-Si (n+)/poly-Si (p)/poly-Si(p+) structure, the concentration, thickness, and the defect states of BSF are discussed. It is shown that the cell performance improves with thickness between 10-15nm, concentration is of the order of 1E19cm-3, the maximum efficiency up to 20.45%.
The Design of the Small Automatic Batching Machine Control System
Authors: Sui Tao , Li Bing , Liu Xiu Zhi , Xu Wen Shang
Published: November 2011

The paper describes a small batching machine control system that takes chip C8051F040 as the core controller. The system that has automatic control and manual control modes can complete the high-precision automatic weighing of few powder and granular material. This article describes the composition of the control system and the major design of hardware, and provides more detailed software program scheme.
The High-Gain Boost Converter for Maximum Power Point Tracking in Photovoltaic System
Authors: Tian Hong Fang , Cao Jian Bo , Li Zheng Xi
Published: November 2011

The aim of this paper is to introduce a high-gain Boost circuit and to use the maximum power model to analyze the principles of maximum power point tracking (MPPT) in photovoltaic (PV) system .The principle is applied to the high-gain Boost circuit and control circuit, through a specific MPPT algorithm to change the duty cycle of Boost circuit realizes maximum power tracking and higher DC output voltage, the control circuit are formed by the CPLD and the AVR microcontroller, through which the control circuit to generate a varying duty cycle and 40KHz PWM pulse to control High-gain Boost circuit. Algorithm uses the incremental conductance method. Experiments show that maximum power point tracking effect is good.
Synthesis and Industrial Trial of New Composite Cationic Flocculant PAFS
Authors: Liu Zhi An , Hu Jun Hu , Chen Jiang Ping , Xue Jin Ying , Liu Qi Wang
Published: November 2011

A compound flocculant, Poly aluminous-ferric-sulphate (PAFS), was prepared with waste slag of a steel work, hematite tailings, concentrated sulfuric acid and fly ash .And it was one-step synthesized with different mole ratio of Fe (Ⅲ)/Al (Ⅲ). The description of product was sticky red liquid and yellow-green solid. Its concentration was 1.45～1.65g/ml, and the concentration of ferric ion is higher than 160g/L, aluminum ion between 10.29g/L and 99.18g/L, the basicity is higher than 12%. According to Ⅴ inferior quality water of DaLaTe plants from Yellow River (the third quarter of Baotou hedong district) we select products with Fe (Ⅲ)/Al (Ⅲ) mole ratio is 10:5. And product PAFS nearly 4 tons in the self-reaction kettle.
Identification and Quantitative Feedback Control of Precision Mechatronic Systems
Authors: Bao Xiu Lan , Luo Xin
Published: November 2011

This paper proposes a robust position controller for a precision mechatronics system, based on the quantitative feedback theory (QFT), to achieve high accuarcy and consistent tracking performance even in presence of considerable structural dynamic uncertainties and external disturbances. Tthe dynamic characteristic of precision mechatronics system is experimentally identified with close-looped identification method, taking account of system uncertainties, and then a QFT controller is designed. Simulations are carried out to validate the efficience and effectiveness of the proposed controller.
Investigation of Mechanical Behavior of Stir Casted Al Based Composites Reinforced With B4C Nanoparticles
Authors: Alizadeh Ali , Taheri Nassaj Ehsan , Hajizamani Mohsen
Published: November 2011

In this study, aluminum alloy (Al-2wt. % Cu) matrix composites reinforced with 1, 2 and 4 wt. % boron carbide nanoparticles with average size of 80 nm were fabricated via stir casting method at 850 °C. The microstructures of composites were studied by scanning electron microscope (SEM). Density measurement, tensile and compressive tests were carried out to identify the mechanical properties of composites and effect of B4C nanoparticles amount. In all fabricated composites, severe agglomeration was observed in the micrographs. With increasing the amount of B4C nanoparticles up to 2 wt. %, yield and tensile strength increased but with more increasing B4C content they were decreased. Also, the compressive strength of samples was increased with increasing weight percentage of B4C nanoparticles.
Effect of Milling and B4C Nanoparticles on the Mechanical Properties of Nanostructured Aluminum Composite Produced by Mechanical Milling and Hot Extrusion
Authors: Taheri Nassaj Ehsan , Alizadeh Ali
Published: November 2011

Mechanical milling was used to synthesize Al nanostructured powder in a planetary ball-mill under argon atmosphere up to 20 h. The same process was conducted for Al-4 wt. % B4C nanocomposite powders to explore the role of nanosize reinforcements on mechanical milling stages. The results show that the addition of boron carbide particles accelerate the milling process, leading to a faster work hardening rate and fracture of aluminum matrix. Tensile of a nanostructured matrix of Al prepared via hot extrusion were investigated before and after incorporation of B4C nanoparticles. The results revealed a, higher yield strength and tensile strength for nanostructured Al matrix in contrast to the commercial coarse grained Al matrix. The same trend was also found to be valid for the nanocomposite samples with respect to the base matrix.
Influences of Tool pin Profile on Microstructure and Mechanical Properties of Al/Cu Composites Fabricated via Friction Stir Processing
Authors: Mostafapour Asl Amir , Darani Saeed Mahmoodi , Givi Mohamad Kazem Besharati , Aghagol Arash
Published: November 2011

Friction stir processing (FSP) was used to fabricate Al/Cu metal matrix composite (MMC). The effects of two different tool pin profiles (straight cylindrical and square) and the number of FSP passes on microstructure, tensile properties and microhardness were studied. The results indicated that good dispersion of micro-sized Cu particles, finer grains, higher tensile properties and higher microhardness, can be achieved by the square tool pin profile compared to the samples produced by the other tool. Also it was observed that the ultimate tensile strength of the samples produced by two FSP passes, as a result of Cu particles shattering, increased intensively compared to the samples fabricated with first FSP pass. Further FSP passes increased the elongation of the composites without any considerable changes in yield and ultimate tensile strength.
Some Investigations of Wet Sliding Behaviour of Al - SiC Particulate Composites
Authors: Mishra A.
Published: November 2011

Pure Aluminium mixed with SiC powder (size 70 micron) in 5, 10 , 15 and 20 percentage weight fractions have been stir cast and test samples have been made. The samples have been machined to produce 8 mm diameter pins for testing in Pin on Disc wear monitor under water lubricated condition. The wear behaviour of these samples has been studied by plotting the wear rates against sliding distance and velocity. The co efficient of friction has been found out under varying load and varying time. The results were compared with that of pure aluminium under similar test conditions. It has been found that the sample having 20% weight fraction of SiC with highest hardness has maximum wear resistance under such conditions.
On Monitoring and Testing System of the Hydropower Unit Vibration Based on Virtual Instrument Technology
Authors: Wu Luo Chang , Nan Hai Peng , Yu Xiang Yang , Zhao Dao Li , Li Na , Ma Chen Yuan
Published: November 2011

In this paper, the advantage of virtual instrument technology is analyzed, and vibration-monitoring system of hydropower unit based on virtual instrument technology was developed combining the requirement of vibration monitoring. The design idea on hardware configuration and functions of each software system module of the system are introduced. The test experiments are made in the laboratory. Experiment results show that the system developed in this paper can realize the function of real-time sampling of the data, monitoring, analyzing, testing and remote diagnosis of the hydraulic vibration.
Performance of Modified Epoxy Resin by Inorganic Packing
Authors: Zhang Lei , Liang Wen Yan , Zhang Ji Feng , Liu Fang
Published: November 2011

We filled different proportions of inorganic packing(nano-silica) in the epoxy resin and investigated the flexural properties of modified epoxy resin compared with pure epoxy resin, based on the mechanics experiments using Zwick/Roell equipment. The experimental results showed the performance of modified epoxy resin by proper proportions of inorganic packing increased significantly compared with pure epoxy resin, but excessive inorganic packing had no help in improving the performance of epoxy resin and even cause some decline of the properties.
Austenite to Ferrite Transformation after Hot Deformation of Low Carbon Steel
Authors: Ferdian Deni , Norman Anton
Published: November 2011

The aim of this work is to get the ferrite nucleation criteria from the recrystallized austenite grain after hot deformation in non isothermal condition. A series of rolling experiments have been performed with industrial C-Mn steel in two different temperatures of 1060 and 960 °C with sequence cooling cycle. The microstructure changes that taking place during hot rolling and after cooling has been examined by metallographic evaluation which allows the identification of ferrite transformation after austenite recrystallization. The recrystallization control was carried out using interrupted cooling method to obtain transformation from actual austenite grain. Using an approach of grain boundary interfacial area (Sv) calculation, which attempts to account the number of sites for potential nucleation of ferrite in thermomechanically processed austenite, an essential correlation of the correspond measured grains was developed. The influence of delay interval time after recrystallization to transformation is observed and the implication obtained is discussed. From those results, a hypothetical interaction between parameter and nucleation is described. It is concluded that, strain and holding time has a major role on the recrystallization process of austenite and bring an effect to ferrite grain refinement. The calculated Sv has indicated the potential sites of nucleation that are proliferated with increasing strain.
Rolling Stock Times and Aluminum Profiles Extrusion Development in China
Authors: Wan Hong Yan , Zhou Zhi Fang
Published: November 2011

Along with our country urbanization step of speed, and a high focus on the Chinese Government to build a countrywide infrastructure network, The Chinese rolling stock industry has seen strong development both in terms of volume and technology in recent years. Currently competition in the market is limited, but with the rapid technological development, more and more competitors are about to emerge. This paper made a detail analysis on Chinese rolling stock industry including its production and market, equipment and technology, development problems and potential, and indicated the main indifference between national industry and international one on this field. At last, author gave the primary suggestions and strategic ideas to the decision makers.
Analysis on the Process of Induction Heating for Shrink-Fit Chuck
Authors: Wang Shu Lin , Zhou Bo , Zhang Wei Zhan , Yang Zhi Jie , Liu Gang
Published: November 2011

According to the principle of induction heating, the skin depth of shrink-fit chuck is determined and the mathematical model of induction heating is constructed. Then a finite element model of induction heating for shrink-fit chuck based on FEM software is set up and the electromagnetic field, temperature field and structure field are obtained. In the end, the paper discusses the influence of the position, current frequency and current density of the coil on the deflection of the clamping bore. Research work provides a theory reference for the design of shrink-fit tool holder and shrink-fit machine.
Finite Element Analysis of Ring-Plate Indexing Cam Mechanism Contact Stress Based on MATLAB and ANSYS
Authors: Li Yan Qi , Liu Ming Tao , Tian Guang Cai
Published: November 2011

This paper is aimed to analyse contact stress of ring-plate indexing cam mechanism which is a new type of indexing cam mechanism. A contact finite element model of the cam and the pin gear is established with the commercial software of MATLAB and ANSYS. With the finite element analysis, the contact stress of the cam and the pin gear is predicted in one motion cycle. On the basis of the finite element analysis, the force and the position of maximum stress are obtained. The conclusion proposed here is reliable to instruct the design of ring-plate indexing cam mechanism.
Resonance Analysis of Manipulators with Flexible Link and Flexible Joint
Authors: Gao Zhi Hui , Bian Yu Shu
Published: November 2011

Worse than common vibration, resonance is a form of severe vibration. It is very important and useful to know what factors and conditions can result in resonance of flexible manipulators, when both link flexibility and joint flexibility are taken into account. In this paper, resonance analysis of the flexible manipulator with both link flexibility and joint flexibility is studied. Based on the flexible dynamic equations, main factors resulting in resonance of the flexible manipulator are analyzed. Furthermore, several conditions exciting resonance are derived and verified with numerical simulations. These conclusions are helpful to predict resonance and useful to the structure design and motion planning for a flexible manipulator to evade resonance
Preparation of Expanded Perlite-Based Binary Eutectic Composite of Phase Change Heat Storage Materials
Authors: Zhang Bao Yun , Jiao Chang Mei , Wang Peng , Jiang Long , Ji Bao Hua , Fang Dong
Published: November 2011

The binary eutectic of lauric acid-stearic acid / expanded perlite composite phase change materials (PCM) was prepared using the method of vacuum impregnation. The structures and properties of this composite PCM were characterized by FT-IR, SEM, DSC and TG analysis. The results showed that the binary eutectic of fatty acid had been composed with porous skeleton expanded perlite completely in a physical method, the phase transition temperature of composite PCM was about 33.0 °C and latent heat was 131.3 J/g. it had a good thermal stability after 100 times of recycling and gave the phase transition temperature 33.5 °C and the latent heat of 128.1 J/g respectively.
Research on Adaptive Rotor Flux Observer with the Speed Feedback and Rotor Resistance Disturbing
Authors: Zhang Yong Jun , Li Xiao Zhan
Published: November 2011

Rotor flux observation is a key step in implementation of a field-oriented vector control system. Aiming at eliminating the influence of the actual speed fluctuation and rotor resistance variety, an adaptive rotor flux observer was proposed to accurately estimate the flux of induction motors in modern high performance drivers, based on the conception of close-loop flux estimation and the extended state observer theory. The performance of the proposed scheme is verified through simulation and experiment.
Kinetics of the Ozonation of Tetrabromobisphenol-A in Wastewater
Authors: Zhang Jie , He Shi Long , Hou Mei Feng , Wang Li Ping , Tian Li Jiang
Published: November 2011

The kinetics of TBBPA degradation by ozonation in semi-batch reactor was studied. The reaction rate constants of TBBPA with O3 and •OH were measured by means of direct ozone attack and competition kinetics, and the values of which were 6.10 l/(mol•s), 4.8×109 l/(mol•s), respectively. Results of kinetic studies showed that TBBPA degradation by ozonation under the different conditions tested followed the pseudo-first-order. The values of apparent rate constant of TBBPA degradation increased with the increase of ozone dosage and pH, but decreased with the increase of initial TBBPA concentration.
An Improved Direct Neural Network Approach to Flatness Pattern Recognition Baseed on GA-RBF
Authors: Feng Xiao Hua , Sun Xiao Juan
Published: November 2011

In this paper, an improved the radial basis function (RBF) neural network direct recognition approach to shape flatness pattern is proposed. The genetic algorithm (GA) is employed to obtain more optimal structure and initial parameters of RBF network. The new approach with the advantages of RBF, such as fast learning and high accuracy, is efficient and intelligent. it can not only effectively settle the problem of the different topologic configurations with changing strip widths but also improve practicability and precision.Compared to the improved direct recognition method with GA-BP,The simulation results show that the speed and accuracy of the flatness pattern recognition model based on GA-RBF are obviously improved.
Numerical Simulation of Dimethyl Ether/Air Laminar Diffusion Combustion Characteristic with the Different Fuel Inlet Velocity and Rotate Speed
Authors: Chen Rong , Wang Hua , Wang Hui Tao
Published: November 2011

The paper establishes physical and mathematical model to study the laminar diffusion combustion, which is formed by concentric jet characteristics of DME/air. It uses commercial simulation software fluent to simulation laminar diffusion combustion process to get the temperature field distribution in different conditions and analyze the simulation results. Simulation results indicates that the faster fuel flow velocity, the higher combustion temperature and higher efficiency without rotate speed conditions, But with the rotate speed, the combustion temperature and the combustion efficiency decrease to half of their original. However, increasing fuel flow velocity on the basis kind of circumstance can make the combustion temperature and efficiency increased.
The Improvement of Anti-Surge Control on Air Separation Compressor
Authors: Jiang Chang Hong , Lu Shao Zhong , Liu Lian Fang
Published: November 2011

This paper mainly describes the reasons for compressor surge and damage, and provide the traditional control method, which can not meet the growing needs, the improved control method, which according to the data using least squares curve to determine surge control regression equation and make the compressor operate safely by using the fuzzy PID control algorithm on the parameter adjustment.
Effects of Additive on the Desulphurization Characteristics of Wastes
Authors: Zheng Bin , Lu Chun Mei
Published: November 2011

Effects of additive on the desulphurization characteristics of wastes were studied by the high temperature tube reactor and the KZDL-4M sulfur analyzer. The results show that after Ba(OH)2 and Fe2O3 is added into experimental wastes respectively, sulfur capture ability of experimental wastes increase effectively. MnCO3 can only improve sulfur capture ability of experimental wastes a little or even little. Suitable additive is a useful way to improve sulfur capture ability of wastes. However, different additive affects sulfur capture ability of wastes differently, three kinds of additive can be sorted as Ba(OH)2＞Fe2O3＞MnCO3.
Effects of Speed Ratio K Value of Rubber-Bar on Cotton Harvesting Performance
Authors: Zhang Hong Wen , Kang Min
Published: November 2011

Structure, cotton harvesting principal and main working parameters of rubber-bar roller harvester were studied in this paper. K value of rubber-bar roller speed ratio was determined based on displacement and velocity equations of rubber-bar end established by work pattern of the roller. The functional relationship between K value and harvest angle β of cotton plant by rubber-bar was derived. Additional, t Additional, the effects of K value on angle β and cotton harvesting performance were analyzed. The experimental results showed that collect rate of cotton was above 95% and percentage of impurities was less than 18% when working speed was 3 km•h-1 and K value ranged between 6.8～8.3.
An Experimental Study on Nitric Oxide Reduction through Coal-Biomass Blend Reburning
Authors: Niu Sheng Li , Han Kui Hua , Lu Chun Mei
Published: November 2011

Nitric oxide (NO) reduction through coal, biomass and their blend reburning is conducted on a drop tube furnace experimental system and it is proved to be feasible of using the coal-biomass blend as the reburning fuel. For a high NO reduction efficiency, the excess air ratio in the reburning zone should be less than 0.9 and the reaction temperature is required to be higher than 1373K. 50-60% of the biomass percentage in the blend is enough for an acceptable efficiency. At the same time, for a thorough NO reduction process, the reburning fuel fraction and the residence time in the reburning zone must be guaranteed about 20% and 0.6-0.8s, respectively. Also, when the initial NO concentration is excess 600ppm, the efficiency is varied little at different NO concentrations.