bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Method of Integrate Simulation Based on ADAMS and Pro/ENGINEER
Authors: Zhao Gang Lian , Jiang Yi , Chen Yu Jun , Ma Yan Li
Published: November 2012

A new method of integrate simulation for the kinematics and dynamics analysis of complex mechanical system is presented in this paper. This platform of the method is based on Visual Studio 2005, MD ADAMS( Automatic Dynamic Analysis of Mechanical System) R3 and Pro/Engineer Wildfire 4.0. The experimental model is built with Pro/E, and then some functions of Pro/Toolkit are used to export file of parasolid format and coordinates of some specified Datum Points. Finally, the coordinates of these Datum Points are written into a CMD file (Commands file of ADAMS). A slider-crank mechanism is used as a numerical example to demonstrate the application of the method. It is shown that this approach is a much easier, faster than usual manual method especially for complex mechanical system which has a lot of Marker Points and constraints.
Design and Simulation of High Spectral Purity Numerically Controlled Oscillator
Authors: Omran Qahtan Khalaf , Islam M.T. , Misran Norbahiah
Published: November 2012

We present a new technique to the design of high spectral purity numerically controlled oscillator (NCO). In this work, a single look up table (LUT) with sine amplitudes at equally spaced samples was used to approximate the complete sine wave cycle. A simple computation process has been conducted to evaluate the slope coefficients, thus the LUT for mapping those values is eliminated. As a result the NCO structure has been efficiently simplified and the memory reduction has resulted in noticeable logic element (LE) saving. The proposed NCO has been simulated using Xilinx toolbox within the MATLAB Simulink environment. It is shown that the spurious free dynamic range (SFDR) of 96 dBc has been achieved and a compression ratio of 256:1 was attained.
Simulation of Mixed Convection around a Square by Using LBM
Authors: Safdari Arman , Kermani E.P. , Azwadi C.S. Nor
Published: November 2012

Laminar natural heat transfer in the horizontal channel with a heated square cylinder has been studied by using lattice Boltzmann method. Air and water are applied as fluid flow and the walls of channel are adiabatic. Lattice Boltzmann method (LBM) as one of stochastic methods has been used to study the hydrodynamic and thermal behaviours of water and air, with Prantle number 7.01 and 0.71, respectively. Velocity and temperature profiles are achieved near each surface of the square. The results show relation between Prantle number and symmetric degree of streamlines and isotherms profile
Robust Control for Enhancing Anti-Interference Performance of Multi-Axle Vehicle
Authors: Zhang Xiao Jiang , Gao Xiu Hua , Zhu Ya Fu
Published: November 2012

The dynamic model of multi-axle steering vehicle undertakes improvements, by taking the anterior axles mechanical steering on vehicle steering performance into account, that is to imply the front-axle wheel angle in control variable and to gear down the difficulty on vehicle control. On the basis of the revised dynamic model, the unit vector continuous robust control method, applied to multi-axle vehicle, is used to analyze the response characteristic of yaw rate and side slip angle under low and high speed. The paper analyzes the strength of unit vector continuous robust control method in multi-axle vehicle combined with minimum and maximum robust control method.The unit vector continuous robust control method for vehicle controling, as the analytical result shows, is able to control object quickly and has the characteristic of certain interference-free feature and higher vehicular control stability; the smaller wave of controlled variable which avoided the buzz of controlled variable, the smallness of control consumed energy, the easy realize of control favor the advance of vehicle economy.
The Optimized Point Stabilization Control for Robots Based on Bézier Planning
Authors: Du Yan Hong , Zhang Wei Yu , Song Xin , Liu Yuan , Chang Ruo Kui
Published: November 2012

In this paper, the optimized point stabilization control of nonholonomic wheeled mobile robot has been researched, and point stabilization control of constraint nonholonomic wheeled system has been achieved through the geometry planning method based on Bézier, and constrained system is converted to un-constraint optimized question based on introducing penalty functions. The optimized control parameters has been got through Hooke-Jeeves method to achieve the perfect combination of the optimized route planning and optimized control, which can make the robot achieve the target pose under the constraint condition and improve the smooth of move path and reduce the stable time. The controller's validity is proved by the experiment.
Size Effect of Uniaxial Compressive Strength of Limestone
Authors: Chen Ze Hui , Liu Chang Wu , Deng Ji Wei
Published: November 2012

Using the MTS testing machine, the uniaxial compressive test of varisized da-qing limestones were undertaken, and the effect of dimensions about compressive strength, peak strain, elastic modulus and destructional forms of rock specimens were studied. It demonstrates that along with the increase of length-diameter ratio, peak strain and compressive strength turn smaller, elastic modulus gradually increases, the destruction of rock samples have a transformation from splitting failure to shear failure. Combined with the test results, Obert L model and Yang Shengqi model, the two size-effect models with extensive applications are analyzed and contrasted. And the conclusion is drawn that Obert L model has a relatively broad applicability, while Yang Shengqi model has a stronger Targeting and higher accuracy. Thus based on the Yang Shengqi model, the size-effect model of da-qing limestone is put forward, and the result indicates that this model corresponds well with the test results, having certain practical value.
Developing a Feature-Based System for Automated Machining Feature Recognition (ISO 10303 AP 224) of Prismatic Components
Authors: Keong Chen Wong , Yusof Yusri
Published: November 2012

Manufacturing is one of the main source of income for a developing country, like Malaysia. Start from the beginning of need in the market, a new concept of product is created. From the initial idea based on a need, this idea is hard to be understood if not presented in any form of drawing or prototype. So, computer-aided design (CAD) has the greatest role in helping to visualise the initial concept of a design with presenting the idea in a graphical view. However, this type of data cannot be used directly for the manufacturing process and normally intervention of human effort is needed to define all the manufacturing features from the component drawing again. This work is laborious if not assisted by computer technology. As a result, this paper aims to design a system and database which has the ability to extract geometrical features from drawings and identify all the manufacturing features which is useful for manufacturing process. This project takes a neutral drawing format, ISO 10303-203, as the input of the system. Then, a mechanism which consists of manufacturing feature extraction and feature recognition will be implemented and lastly, a new form of manufacturing feature-based data, ISO 10303-224 will be acquired for the subsequent manufacturing process.
An Optimization Harmonic Elimination Control Technique for Cascade Multilevel Inverter
Authors: Wang Bing Yi , Zhai Shuang , Zhu Xiao Qian
Published: November 2012

In order to improve the quality of cascade multilevel inverter’s output voltage, this paper introduces an optimization harmonic elimination control technique. The harmonic of cascade multilevel inverter is controlled by the switch angels of inverter units. Through this technique, switch angels eliminate the low and middle frequency harmonic compositions and at the same time make total harmonic distortion rate of cascade multilevel inverter low are found. The correctness and accuracy of optimization harmonic elimination control technique are validated by simulation and experiment model.
Study and Investigation on the Mach of Impeller Outlet and Diffuser Inlet in Stamping and Welding Centrifugal Pump
Authors: Gan Jian Jun , Mou Jie Gang , Zheng Shui Hua , Zhu Bo
Published: November 2012

Based on CFD simulations and experimental research, this paper studied the mach of impeller outlet and diffuser inlet in stamping and welding centrifugal pump. The influence of area ratio Y of impeller outlet to diffuser inlet on pump internal flow characteristics and performance was studied. Five different area ratio pump models were analyzed. The results indicate that as the area ratio Y= F3/F2 increase, the velocity of fluid in diffuser inlet decreases continuously, the average static pressure of diffuser outlet increases, and the head and efficiency of the pump are risen. When the area ratio increases from Y=1.48 to Y=3.49, the head increases about 3.0% and the efficiency about 2.0%.
Soft Start Design of Controlled Transmission for Belt Conveyor
Authors: Wang Xin Huan , Zhou Fei , Fu Zi Yi
Published: November 2012

According to the request of equipment for high-power belt conveyor, the controlled soft start equipment based on PLC was designed. The soft start process was analyzed and the idea velocity and acceleration curve of start process and the driving circuit of electro-hydraulic proportional valve were given, also the control strategy was designed. Through experiments test, the electrical control system designed in this article is able to control accurately mechanical transmission and hydraulic device and can finish the soft start function for belt conveyor.
The Gray Correlation Analysis of the Surface Medium Character of Adhering Casing
Authors: Meng Xiang , Ai Chi , Hao Ming , Zhao Wan Chun , Li Teng
Published: November 2012

According to the alternation of the exterior situation of adhering sand casing, the exterior asperity should be developed, and the fluid drag force between the casing and the cement mantle should be increased, then the cementing strength and the cement job quality between interfaces could be increased. The cementing strength between the adhering sand casing and the interface of cement mantle is related to sand grain diameter, distribution density and the thickness of adhering sand agent, according to the results of in-house experiment, by using gray correlative analysis method the degree of association between the cementing strength and the preceding effects has been separately calculated to be 0.436, 0.246 and 0.318.
Design of Transformer Silicon Steel Cutting Line Drive System Based on Friction Compensation
Authors: Ding Chao Yi , Guo Hong Che
Published: November 2012

Focused on transformer silicon steel cutting line feeding drive system which is made of permanent magnet linear synchronous motor, this paper proposes and designs a new kind model about friction exists in the system, viz. within a little speed range the model prescribes a little static friction interval, in where speed is prescribed for zero. Not in this small speed range, it is prescribed for sliding friction interval. So that the model divides the whole sphere of action of the friction into two sections, then the paper discusses each part respectively, finds out the model parameters of each parts, basing on these, friction compensation is used to control the impact of friction on system performance. Afterwards, the paper uses recursive least squares (RLS) to estimate the total mass of mover and its load, and viscous friction coefficient, then the paper uses the estimated values to amend the corresponding parameters in the friction model, and improves the friction compensation effect. Finally, simulations were carried out, the results show the impact of various part on the system performance, and also prove the validity of the friction compensation in the transformer silicon steel cutting line feeding drive system, which is made up of permanent magnet linear synchronous motor.
Galvanostatic Removal of Chlorides in Cast Iron Artifacts
Authors: Guo Shao Wen , Ou Yang Wei Zhen
Published: November 2012

Chloride ion migration and the choice of optimized current density during galvanostatic dechlorination of simulated cast iron artifacts in alkaline solution were studied by means of galvanostatic polarization. The results showed that the more treatment time and the more current density, the more was the extraction ratio of chloride ion and the less was the electrical efficiency. The current density was optimized with respect to the extraction ratio of chloride ion and the electrical efficiency, and the optional current density was presented.
Leveling-Based Kanban Calculation in Production System
Authors: Deng Qian Wang , Wang Jie You
Published: November 2012

The paper defines replenishment time based on the leveled consumption controlled loop in production system. Then it proposes a method of Kanban calculation. Traditional production system dose not consider leveling principle, thus the replenishment time is not accurately and more likely to double or miss counting number of Kanban. In the paper, Replenishment time is specified into more parts to reflect all influence in production process, and leveling combined with consumption controlled loop is taken into consideration for the replenishment definition. A new defined replenishment time is a base of Kanban calculation. A method of Kanban calculation could be built. It could decrease the possibility of double or miss counting number of Kanban. A case study is given to prove feasibility of the method of Kanban calculation.
The Effects of Parameter Settings on Shrinkage and Warpage in Injection Molding through Cadmould 3D-F Simulation and Taguchi Method
Authors: Othman Mohd Hilmi , Shamsudin Shazarel , Hasan Sulaiman
Published: November 2012

This study is focused on the effects of process parameters in plastic injection molding towards shrinkage and warpage problem of High Density Polyethylene (HDPE) specimen. The aim was to identify the main effects of different process parameters on warpage and shrinkage defects via numerical simulation software and experimental validation. Series of simulations were carried out using Cadmould 3D-F in order to utilize the combination of process parameters based on three level of L9 Taguchi orthogonal design. The Signal to Noise (S/N) ratio and the Analysis of Variance (ANOVA) were used to optimize the levels and to point out the impact of the process parameters on warpage and shrinkage. From the results, it showed that the most affected parameter on the warpage and shrinkage is packing time, with the P value of 48.93%, followed by melting temperature with 40.58%. The filling time and packing pressure were not a significant factor because they only contribute 7.30% and 3.19% of P value, respectively.
Considering the Influence of Chemical Reactions between Detonation Products on Specific Heat Ratio Calculating of the TNT Explosive with Small Explosive Charge Volume Ratio
Authors: Zhong Wei , Zhou Tian
Published: November 2012

The formula and calculating method of specific heat ratio in confined explosion with small explosive charge volume ratios under considering chemical reactions of the detonation products was researched. Taking the TNT explosive as an example, a numerical calculating program was written, and the specific heat ratio of the confined explosion either considering the influence of the chemical reactions or not were calculated by the program.
Fractal Character of Structural Control on Uranium Mineralization in South China
Authors: Xie Yan Shi , Tan Kai Xuan , Chen Liang , Huang Wei , Hu Kai Guang , Wang Xiu Cai
Published: November 2012

South China is the most important uranium producer in the country. Most uranium deposits in south China are strictly controlled by NE-NNE trending regional fracture structure. Fractal analyses on spatial distribution of uranium deposits and regional fracture structure in south China have been done in this paper. It indicates that the spatial distribution of both uranium deposits and regional fracture structure in south China show fractal character. The fractal dimension D=1.4142 for the spatial distribution of regional fracture structure is significantly greater than the critical value and it indicate a higher ripening degree in the fracture structure evolution and an advantages to fluid flow and uranium mineralization. The fractal dimension D=1.0527 for the spatial distribution of uranium deposits in south China show a lower complexity than regional fracture structure. The fractal spatial distribution of uranium deposits in south China is the result of the evolution of the fractal fracture structure system.
Interference between the Gas Wells in the Method of the Pesudo-Pressure
Authors: Yin Dai Yin , Zhou Wei , Lu Jian Xin , Zhang Cheng Li
Published: November 2012

During the developing process of gas reservoirs, different gas well spacing will affect the production of the well and the bottom hole pressure. In this paper, the method of the advanced mechanics of fluids in porous media, the pressure changes into the pesudo-pressure, the changes of the pressure near the well have been obtained. Theoretical model of the gas reservoir has been established, which is built with constant pressure as internal boundary control conditions and infinite formation as outer boundary control conditions. According to the seepage differential equations of the pesudo-pressure, the changes in the production on bottom pressure can be derived in different well spacing. Then the pressure and production curves have been drawn.
Research and Analysis of the Economy and Environmental Benefits of Electric Propulsion Systems in Marine
Authors: Zong Jun Hua , Mei Lei , Wang Da Zheng , Zhang Ya , Wang Dan
Published: November 2012

Electric propulsion uses stepless variable speed (CVT), and it’s supplied stable power with generator to achieve the purpose of fuel economy. This paper will contrast fuel consumption of traditional propulsion and electric propulsion in multi-working condition ship. For a 36m tuna longline vessel, in this paper ,fuel consumption and fuel economy of these two propulsion methods are analyzed, and it turned out: the electric propulsion method can save fuel 25.1 tons per year, be equal to saving fuel costs 20.8 million RMB and reduce carbon dioxide emissions by 80 tons per year.
Power Economic Dispatch Problems Considering Prohibited Operating Zones and Spinning Reserve: A Hybrid Differential Evolution
Authors: Chiang Chao Lung
Published: November 2012

This paper proposes a hybrid differential evolution (HDE) for power economic dispatch (PED) considering units with prohibited operating zones (POZ) and spinning reserve. The HDE equipped with an accelerated operation and a migration operation can efficiently search and actively explore solutions. The multiplier updating (MU) is introduced to handle the equality and inequality constraints of the system. To show the advantages of the proposed algorithm, one example is investigated, and the computational results of the proposed method are compared with that of the previous methods. The proposed approach integrates the HDE and the MU, revealing that the proposed approach has the following merits - ease of implementation; applicability to non-convex fuel cost functions; better effectiveness than previous methods; better efficiency than differential evolution with the MU (DE-MU), and the requirement for only a small population in applying the optimal PED problem of generators with POZ and spinning reserve.
Mazdak Technique for PSNR Estimation in Audio Steganography
Authors: Mazdak Zamani , Azizah Bt Abdul Manaf , Shahidan M. Abdullah , Saman Shojae Chaeikar
Published: November 2012

A novel method to estimate PSNR of the result of audio steganography before embedding is presented. Estimated PSNR by proposed linear interpolation formula was tested and the result was almost the same with the obtained PSNR in practical way.
Study of Synthesis of Novel ɤ-Valerolactone-Based Polyurethanes
Authors: Chalid Mochamad , Heeres Hans J. , Broekhuis Antonius A.
Published: November 2012

The ring opening of -valerolactone (GVL) with amine compounds was reported as a promising molecular engineering tool to synthesize precursors for new bio-based polymers such as polyurethanes (PUs). Experimental work on the synthesis of polymers based on GVL/1,2-ethanolamine and GVL/1,2-diaminoethane adducts, and di-isocyanates (1,4-phenylene-di-isocyanate (PDI) 2,4-toluene-di-isocyanate (TDI) and hexamethylene-di-isocyanate (HDI)) is described. The polymers were characterized by FTIR, 1H-NMR, 13C-NMR, elemental analysis and GPC. The best polymerization results were obtained using TEA as the catalyst, DMA as the solvent and a temperature of 140°C for the reaction of the GVL/1,2-aminoethanol adduct with TDI. A polymer with a molecular weight (Mw) of 156 KDalton was produced in 97% yield.
Research on Corrosion Characteristics of Mild Steel in Sea Water at Weihai
Authors: Wang Yan Gang , Tong Xing Hua , Jiang Yong , Liu Yong , Zhu Lin Sen
Published: November 2012

The corrosion characteristics of mild steel in real sea water are investigated by electrochemical test in this paper. Polarization curves and electrochemical impedance spectroscopy (EIS) are got by electrochemical workstation. From polarization curves, it is found that the corrosion rate rises at the initial period, and it becomes the highest on the 3rd day, then drops, and it tends to be stable after about 15 days, which is confirmed by EIS. In addition, the experiments also show that the corrosion layer can suppress the corrosion process. The electrochemical corrosiveness of the mild steel is analyzed in this study, and it lays a foundation for anticorrosion technology research.
Performance Improvement and Lightweight of Engine Hood Structure
Authors: Wan Chang Dong
Published: November 2012

Engine Hood is an important part of a whole auto body panels, Structural stiffness and vibration modal always are considered while designing. After structure analysis of original engine hood, some defects were found. Based on the theories of topology optimization , topography optimization and size optimization, some constraints for the displacement, the modal, the volumetric fraction were set up, firstly, minimum strain energy was set up for the optimization objective; secondly, the minimum mass was set up for the objective. After computation, an optimized shape and material distribution for the structure was shown. Then, the structure was redesigned, and then it was computed with method of size optimization. The results of recomputation showed that the engine hood structure capability was superior to the original and the new hood weight was also reduced.
A Novel Micro Check Valves Used for Interstitial Fluid Sampling Device
Authors: Huang Bo , Xi Hong Zhu , Liu Ya Xin , Yao Yu Feng
Published: November 2012

Design, simulation, flow characteristics of micro check valves used in Interstitial Fluid (ISF) devices are presented in this paper. The micro check valve includes three layers: the upper valve seat, the lower valve seat and the middle membrane layer which is fabricated by a polymeric surface micro machining process, which utilizes SU-8 as the functional material. The structure of membrane is designed as a disc with 1.2 mm diameter suspended on 4 folded beams, which work as valve springs. Maximum deformation and stress of membrane (50 μm, 100 μm, 150 μm, 200 μm, and 250 μm thicknesses) have been analyzed with ANSYS under 70 kPa. Simulation results reveal the membrane size is how to affect the performance of it. Finally, the membrane is fabricated with 150 μm SU-8 layer, and it is successfully integrated into the ISF sampling device. The forward flow and cut-off performance of the micro check valves have been observed with water. The flow curves were obtained under different forward and backward pressure. Experiment results shown that flow rates in the forward direction is small, and the flow rate is about 450 μL/min under 70 kPa; the valves can withstand more than 83 kPa pressure, and the reverse flow is nearly to zero, which meets the requirements of the ISF sampling device well.
Friction and Forward Slip in High-Speed Cold Rolling Process of Aluminum Alloys
Authors: Wang Qiao Yi , Zhu Yao , Zhao Yong
Published: November 2012

Effects of process parameters on friction in cold strip rolling process have been studied in this article. The prime objective is to examine the major parameters affecting the metal working process. A varying coefficient of friction through the roll contact arc has been determined. A few formulae, commonly used to predict the coefficient of friction from forward slip measurements of a rolling process, have been evaluated according to forward slip measurements and coefficient of friction data. Essentially, this article bridges the industrial constant coefficient friction approach from forward slip measurements with the academic varying coefficient of friction strategy. A systems analysis has been made regarding the effects of potentially important parameters on friction in cold rolling. Based on this analysis, the effects of a few parameters have been identified of most importance.
Finite Element Analysis of Tube Tower for Vertical Axis Wind Turbine
Authors: Liu Bin , Zhang Yuan Yuan , Zhao Fu , Gong Yan Jue , Meng Chun Ling
Published: November 2012

It is very significant for the vertical axis wind turbine to design the best support structure with high strength and stiffness. This paper discusses modeling a kind of tube tower structure of the vertical axis wind turbine and carries out static and modal analysis based on the finite element method. The static and modal characteristic of tube tower such as stress, strain and mode shapes are obtained accurately which can provide basis to optimal design the support structure for vertical axis wind turbine.
Optimization Research of Process Parameters for Laser Cladding Valve Parts Based on Genetic Algorithm
Authors: Wang Jian Bin , Yin Ji Shu
Published: November 2012

The optimization research of process parameters for big power Laser cladding valve parts, is a research focus of modern surface hardening technology. The article discussed in detail for solving the optimum process parameters of Laser cladding for the selection approach of strategy of genetic algorithm, the quantitative relationship model was established between process parameters and the valve parts property using neural network method , which process parameters are laser power (P), scanning speed (V), powder feeding rate (G), scan spacing (D) and thickness ( ) etc., the best configuration program of Genetic Algorithm control parameters has been obtain by means of the parameters encoding、initial group setting、fitness function design,genetic operation design and algorithm control parameters setting. The optimization of process parameters is obtained to fit the Laser cladding technology by using genetic algorithm toolbox in the MATLAB environment, and the optimization goal of the valve parts property has also been achieved. Practice has proved that the optimal process parameters are correct by the genetic algorithm , and has a very good production practice guide.
Study on Characteristics of Gas Flow Velocity in Catalytic Converter with Porous
Authors: Cai Zhan Jun , Kang Wei Min , Cheng Bo Wen , Li Ya Bin
Published: November 2012

This paper studies the different porosity of porous medium how to affect the flow velocity field under the conditions of same inlet velocity and fiber diameter by CFD method. Geometric model of the catalytic converter has been established and meshed by the pre-processing tool FLUENT. The flow speed simulation filled contours and velocity distribution curve of the fiber porous material show that reducing properly the porosity may improve the uniformity of the velocity in Y and Z direction of the porous material. The less porosity is beneficial to exhaust catalytic reaction.
Study on the Meshing Feature and Contact Strength of WN Gear Driving in Load Bearing
Authors: Li Cheng Chao , Chen Dian Hua , Li Yu Guang , Mu Xiao Kai
Published: November 2012

According to characteristics of WN gear multi-point meshing and double-arc tooth contact, the finite element analysis model of the WN gear drive is established by Pro/E and ANSYS modeling techniques. The contact way and meshing feature of the WN gear under the different conditions and parameters are studied by three-dimensional dynamic meshing simulation analysis of gear drive. The analysis model of contact strength at loading driving is established by three dimensional geometric contact characteristics and elastic deform theory. Impact of helix angle and center distance error in the calculation of WN gear contact strength on maximum contact stress is analyzed. The results show that increase of the helix angle and a slight decrease of the center distance can improve the contact strength.
Study of Side Thrust of Diesel Piston Based on Time-Domain Finite Element Method
Authors: Zheng Da Yuan , Cao Yi Peng , Zhang Wen Ping
Published: November 2012

Grasping the transmission of side thrust of piston is one of the effective methods to control engine vibration and noise. The paper uses time-domain FEM to study engine vibration. Firstly the finite element model is established after simplifications and modal analysis is conducted. Then the side thrust of piston is calculated and applied to cylinder liner using equivalent nodal load. The surface vibration is gained, from which it can be concluded that the displacements of upper block and top cylinder head reflect changes in cylinder pressure, while the vibration of observation window is complex. Finally, the vibration in a variety of engine working conditions is analyzed. Under load characteristics, the amplitude of engine surface vibration changes with loading; under propulsion characteristics, the surface vibration is essentially the same.
Rotor Profile Generation Method for Twin Screw Compressors Based on Bi-Direction
Authors: He Xue Ming , Han Ming , Deng Yang , Lu Yi , Hua Chen Liang
Published: November 2012

The performance of twin-screw compressor is mainly decided by profiles of the two rotors. The constitution of new rotor profiles is studied, meanwhile the key technology of generating rotor profiles are mainly studied in this paper. A new method based on forward and reverse direction for generating rotor profiles with meshing lines is proposed.
A Modified Model of the Primary Shear Zone for Orthogonal Machining
Authors: Zhou Fang Juan , Wang Xue Lin , Hu Yu Jin
Published: November 2012

A new modified model based on the non-parallel primary shear zone is presented in this paper. Experiments showed that the primary shear zone in cutting process wasn’t an absolutely parallel-sided zone. In fact, there are small inclined angles in the primary shear zone. Therefore, in this paper, a correction coefficient is proposed to predict cutting forces exactly. The coordinate mapping approach is adopted to obtain the correction coefficient and the software MATLAB is utilized to predict cutting forces. The material of stainless steel 316L is used to validate the modified model. By comparison between predicted analysis and experimental results, the proposed model shows good agreements with experiments.
Research on Dynamic Characteristics of Implement Mechanism of Mining Excavator
Authors: Kong Wei Kang , Liu Jia Xin , Ma Ming Hui
Published: November 2012

This paper works on the dynamic characteristics of implement mechanism of mining excavator. The dynamic model of the working implement is established based on the application of Lagrange's equation. Digging resistant force, crowd force and ore gravity were discussed in detail. A full working cycle is simulated by using Matlab/Simulink. The results show the validity of the established dynamic model and the importance of the dynamic analysis for the mining excavator.
Research on Anti-Backward-Tipping Device of Luffing Jib Tower Crane
Authors: Li Bin , Cai Bing , Liu Hong Da , Wang Fu Mian , Zhang Jin Sheng
Published: November 2012

When the crane jib is in the maximum elevation angle，luffing jib tower cranes can happen to produce accidents of crane jib backward- tipping. The anti-backward-tipping device is the necessary safety device luffing jib tower crane. Based on the study of several anti-backward-tipping devices, this paper analyzes the causes and forced state of crane jib backward- tipping and proposes several factors to be put into consideration in designing anti-backward-tipping device. It proposes a design method and calculation method of dual-spring anti-backward-tipping device, which has been applied and verified in product design.
Experimental Study of Cutter Wear Based on Turn-Milling
Authors: Cai Yong Lin , Huang Chao , Li Jian Yong
Published: November 2012

Based on analyzing the contact condition of the cutter and the work piece in orthogonal turn-milling machining, orthogonal cutting experiments were implemented with several machining parameters, and finally obtained conclusions about cutter wear and work piece roughness influenced by 3 factors. The biggest effect factor which affects the cutter wear is the cutter offset, the number of cutter teeth takes the second place, and the axial feed rate affects the least to cutter wear. This conclusion can be used to choose fit machining parameters in turn-milling machining.
Research of the Three Coordinates Miniature CNC Milling Machine
Authors: Sima Zhong Wen , Zhang Hai Yun , Zhao Yu Gang
Published: November 2012

An open three coordinates computer numerical control (CNC) system was developed, which was based on PC and PMAC motion controller. A three coordinate's miniature CNC milling machine was researched with a simple structure, low cost, small volume and suitability for teaching, and so on. Meanwhile the CNC system had the advantages of 3-axis linkage, program editing, manual operation, inching operation, simulation processing operation, automatic operation and dynamic display of the trace. The system is based on the Windows XP platform and it is convenient to manipulate with friendly interface.
The Mechanism of the Contact Resistance between Rail and Wheel in Bad Shunting Area
Authors: Huang Zan Wu , Jin Kai Rui , Sun Ling Yao
Published: November 2012

The bad shunting of track circuit results from the contact resistance between wheel and rail and its solution becomes a disturbing problem for electrical engineer technicians. Based on the Holm electrical contact model, Greenwood model and thermal breakdown theory, this paper analyzed the mechanism of contact resistance between wheel and rail. Then breakdown characteristic of the imperfect electrical layer is analyzed. Through field test, its character is similar to reversed breakdown of diode and the contact resistance decreases as the current ascending. The conclusions of the experiments not only prove the validity of Holm and Greenwood model, but also provide the professional and practical parameters for solving bad shunting. And these parameters involve the breakdown voltage and short-circuit current.
Crystal Growth of Ni on Liquid-Solid Interface
Authors: Wang Li , Fang Teng , Qi Yu
Published: November 2012

Molecular dynamics simulations have been performed to explore the crystal growth of solid - liquid interface of pure Ni by using a potential of embedded atom (EAM) type. The solid-liquid interface is structured by liquid-solid-liquid, considering the (100) orientation. The crystal growth rates are determined by observing interfacial moving velocity, the calculated kinetic growth coefficient μ, which is defined as the ratio of kinetic growth velocity to the interface undercooled temperature, is 60cm/s/K. The melting temperature determined by time dependence of the volume per particle for different temperature is 1740 K, which is well agreement with experimental values and other simulated ones.
Static and Dynamic Characteristic Analysis of the Tower for Vertical Axis Wind Turbine Based on Finite Element Method
Authors: Gong Yan Jue , Zhang Yuan Yuan , Zhao Fu , Xiang Hui Yu , Meng Chun Ling , Zhang Yuan
Published: November 2012

As an important part of the vertical axis wind turbine, the support structure should have high strength and stiffness. This article adopts finite element method to model a kind of tower structure of the vertical axis wind turbine and carry out static and modal analysis. The static and dynamic characteristic results of tower in this paper provide reference for optimization design the support structure of wind turbine further.
Difference in Electronic Structure between Diamond and Graphite
Authors: Gong Jian Hong , Lin Shu Xia , Li Wang , Gao Jun
Published: November 2012

The structural and electronic properties of diamond and graphite were investigated by the first-principles total-energy pseudopotential method based on density functional theory. The band structure, DOS and PDOS were calculated. Results showed that diamond had a wide band gap, and its direct transition energy is 6.0 eV. But graphite’s band gap is about zero, meaning without transition energy. That explains the reasons of diamond acting as an insulator but graphite acting as a conductor. DOS and PDOS analysis results indicate both diamond and graphite are sp hybridization and p states contribute mostly to the bonding of crystal. While their covalent bonds style are different.
Experimental Study on the Hydrodynamics of Swirling Fluidized Bed
Authors: Jun Goo Jia , Raghavan Vijay R. , Sing Chin Yee
Published: November 2012

In recent years, the Swirling Fluidized Bed has been regarded as one of the novel designs in fluidization technology. This new technique features an annular blade distributor which injects the fluidizing gas through a certain inclination, is capable of fluidizing the bed and at the same time causes swirling motion of particles in a circular trajectory. In the present work, the fluidization characteristics and hydrodynamics of a swirling bed are studied using an experimental approach. The behavior of gas-particle interaction in a swirling bed in terms of operation regimes, trend of pressure drop across the bed and the hysteresis effect, are explored with varying bed configurations. Seven sets of particles, three in spherical shape, two in cylindrical shape and two in irregular shape, are used as bed material by considering bed weights from 500 g to 2000 g and blade overlap angles 18° for air velocities up to approximately 3.5 m/s and blade inclination of 10°. The results evidently showed that particle configurations dramatically affect the beds’ behavior.
Effect of Strain-Rate on Flexural Behavior of Composite Sandwich Panel
Authors: Abdi Behzad , Koloor S.S.R. , Abdullah M.R. , Amran Ayob , Yahya Mohd Yazid
Published: November 2012

In the past few decades, Composite Sandwich Panel (CSP) technology significantly influenced the design and manufacturing of high performance structures. Although using CSP increases the reliability of structure, the important concern is to understand the complex deformation and damage evolution process. This study is focused on the mechanical behaviour of CSP under flexural loading condition. A setup of three-point bending test is prepared using three support span of 40, 60 and 80 mm. The loading was controlled by three different displacement rates of 1, 10 and 100 mm per minute to examine the effects of strain-rate on bending behaviour of CSP material. The beam span significantly affects the flexural stiffness of CSP panel. The load-deflection response of the panel shows two different portions, that representing equivalent elastic and plastic regions in both the core and facesheets components of CSP. The non-combustible mineral-filled core appears to be nonlinear in the elastic region, at high loading rate. Consequently the failure occurs as the core/facesheets interface suffers debonding.
Comprehensive Study on Variable Pitch Vertical Axis Tidal Turbine
Authors: Syed Shah Khalid , Zhang Liang
Published: November 2012

To overcome the stalled effect and poor starting torque of fixed pitch Darrieus turbine, researchers invent variable pitch vertical axis tidal turbine (VATT). For tidal stream designers main challenge is that the design can sustain in hostile marine environment. Due to lift base design VATT is very critical for cavitation, so appropriate parameter selection can improve the hydrodynamic performance and life of the turbine. An attempt is made to optimize the design parameters of VATT for variable pitch using ANSYS CFX, hereafter CFX, which is based on a Reynolds-Averaged Navier-Stokes (RANS) model. A transient simulation is done for variable pitch VATT using Shear Stress Transport turbulence (SST) scheme. Main hydrodynamic parameters like torque T, combined moment CM, coefficients of performance CP and coefficient of torque CT, etc. are investigated. The modeling and meshing of turbine rotor is performed in ICEM-CFD. Mesh motion option is employed to achieve variable pitch phenomenon. This article is the one part of the ongoing research on turbine design and developments. The numerical simulation results are validated with analytical Matlab results performed by Edinburgh Design Ltd. The article concludes that CFX simulation is done accurately and major parameter selections for turbine development are feasible.
A Novel Single-Stage PFC Based on Active Clamp Forward Converter
Authors: Zhu Yong Xiang , Xiao Qiang Hui , Tong Sheng Xiao
Published: November 2012

This article describes a new novel single-stage PFC converter circuit based on active clamp forward. The circuit of the PFC converter and active clamp DC/DC converter together. It is suitable for a lot of the power supply application fields with simple structure & low cost. Also this article analyzes its detailed operating principle, and the circuit switches process especially. The experimental prototype test results show that the circuit topology to achieve the main switch & the auxiliary switch with the zero voltage turn-on, and the power factor being above 0.98, the efficiency being more than 88% at rated conditions.
Study on Reliability of Control and Protective Switching Device
Authors: Huang Shi Ze , Guo Qi Yi , Hu Jing Tai , Zhang Min Juan , He Ya Jie
Published: November 2012

After introducing the new low-voltage protective electrical apparatus—Control and Protective Switching Device (CPS), there came to the importance and social benefits of its reliability. According to the study on CPS’s operation characteristics and failure modes, along with the current national standard and related industry standard, the two reliability indexes were proposed to measure CPS’s reliability for the first time, and the reliability compliance test plans were also provided. All the study did provide a reference for the reliability research work of CPS.
Novel Multi-Finger Power HBTs with Non-Uniform Segmented Emitter for Thermal Stability Enhancement
Authors: Jin D.Y. , Lu D. , Zhang W.R. , Fu Q. , Zhang Y.J. , Zhao X.
Published: November 2012

With the aid of a two-dimensional thermal-electrical model, the thermal stability of multi-finger power heterojunction bipolar transistors (HBTs) with uniform segmented emitter, and non-uniform segmented emitter are studied. It shows that both of them could lower the peak temperature and improve the non-uniformity of the collector current density distribution, and thus improve the thermal stability, compared with an HBT which has traditional non-segmented emitter structure. At the same time, the improvement capability of thermal stability for HBT with non-uniform segmented emitter is superior to that of HBT with uniform segmented emitter, ascribing to selectively divide the emitter fingers into various segments according to the difference of heat dissipation capability in emitter fingers. Furthermore, the improvement capability of thermal stability for HBT with non-uniform segmented emitter is enhanced exponentially as segment spacing increases. However, for HBT with uniform segmented emitter, the ability is less sensitive to the increasing of the segment spacing as it exceeds 6μm. Therefore, the technique of non-uniform segmented emitter is a better method for enhancing the thermal stability of power HBTs.
Working Parameters Selection of Bladder-Type Accumulator under the Different Conditions
Authors: Wu Xiao Ming , Yang Yan Fang
Published: November 2012

Currently there is a lot of material presented on the selection of different conditions and specific formula in order to select accumulator parameters. Yet these formulas are calculated in different degree of approximation and assumptions. This paper mainly considers the effect of the poly index and temperature to the working parameters in the charge process; and designs the software package of parameter selection of the accumulators. The key index formula is derivated, and the more accurate total volume V0 can be given trough computation. It is accurate basis for the selection of the accumulator.
The Analysis and Research of Electric Dynamic Load Simulator
Authors: Liu Xia , Yang Rui Feng , Jia Jian Fang
Published: November 2012

The aero load simulator is a typical application of electric dynamic load simulator in the engineering. It is important half hardware-in-loop simulation equipment, which is often used to simulate the aerodynamic torque load on the missile rudder or elevon actuators in the flight. The mathematical model of the electric dynamic load simulator is built using the physical modeling method. The influence of the rudder performance on the model was considered, and modeled it as the disturbance channel in the model. The electric dynamic load simulator is a typical coupled system. Under the different simplification, the validity of the model is verified by the actual experiment.
Researches on the Characteristics of Vacuum Switching Arc in Short-Gap
Authors: Qiao Gui Hua , Dong Hua Jun , Li Min , Dong Wen Liang , Zhou Xin Wei
Published: November 2012

The forms and the V-I characteristics of vacuum arc have great influence in the vacuum circuit breakers’ protection and control of power system. An experimental set-up was thus designed for vacuum switching arc measurement of V-I characteristics was used and an image collection system was designed to collect the images of vacuum arc used high-speed camera CMOS with the experimental setup, the V-I characteristics and forms of vacuum arc was researched, the curve of V-I was drawn and the images was analyzed. All these provide experimental basis for the analysis on basic physical theory of vacuum switching arc.
Development and Application of Low-Speed and High-Torque Permanent Magnet Synchronous Motor
Authors: Cui Jun Guo , Xiao Wen Sheng , Zhao Jian Bo , Lei Jing Xi , Wu Xiao Dong , Wang Zhi Gang
Published: November 2012

To meet the demands of direct-drive petroleum equipment, developed a low-speed and high-torque permanent magnet synchronous motor. By analyzing and identifying the suitable key parameters such as permanent magnet structure parameters, air gap length, type and size of Stator Slot and so on, designed permanent magnet synchronous motor with the torque 10800 Nm, the rated speed 30 r/min and high efficiency and power factor. Obtained the flux density distribution situation and characteristic curves under no-load working condition through simulation and analysis. Manufactured the low-speed and high-torque permanent magnet synchronous motor and applied it to pumping unit. Test results show that this motor has many advantages such as wide range of speed regulation, small torque ripple, smooth operation and other characteristics. The Direct-drive Pumping Unit used this permanent magnet synchronous motor can save 20% energy than the beam pumping unit, so its social and economic benefits are significant.