bluuebunny/crossref_metadata_2025 huggingface dataset:
Future Methods of Adult Education
Authors: Hope John K.
Published: September 2010

The purpose of this chapter is to provide a vision of future information and communication technology based methods of adult education informed by recent pedagogical and technological developments. Macro trends that may influence the future of adult education methods are examined, followed by detailed scrutiny of particular methods that are likely to be utilised in the near future. The chapter concludes with a review of the more distant future and suggestions to adult educators.
Algorithm of the Scanning Path Based on SLC Files in Rapid Prototyping
Authors: Wu Mao Liang , Hua Lin Jun
Published: September 2010

The paper analyzes the structure of SLC file format which is used in rapid prototyping technology, and studies the algorithm of the scanning path through improving the line-filling algorithm. The scanning path is carried out with VC++ software and the wind power generator blade and car logo are dissected to validate the algorithm. At last, the paper analyzes the influences of the slice thickness and hatch gap on the paths, and compares the file sizes and the scanning path length under different file formats and scanning parameters.
Test Pattern Generation of VLSI Circuits Using Hopfield Neural Networks
Authors: Pan Zhong Liang , Chen Ling , Zhang Guang Zhao
Published: September 2010

A new test pattern generation method for the stuck-at faults in VLSI circuits is presented in this paper, the method uses Hopfield neural networks and chaotic simulated annealing. The Hopfield neural network corresponding to a digital circuit is built, the test patterns of faults in digital circuits are produced by computing the optima of the energy function. A chaotic simulated annealing algorithm is designed, which combines the features of chaotic systems and conventional simulated annealing, it is able to take the advantages of the stochastic properties and global search ability of chaotic system. The algorithm is used to compute the optima of the energy function of neural networks in order to produce the test patterns of faults. Experimental results show that the test pattern generation method proposed in this paper can produce the test patterns in short time for both single stuck-at faults and multiple stuck-at faults in digital circuits.
Research on CANopen-Based Intelligent Sensor for Ship Monitoring System
Authors: Wu Yun Feng , Liu Bo
Published: September 2010

In order to enhance reliability and maintainability of ship monitoring system, this paper proposed a CANopen protocol-based intelligent sensor which can simultaneously monitor rotational speed and temperature. With the presented intelligent sensor, the data collection and sensor control can be achieved easily and effectively. Experiments were conducted, which showed that the presented intelligent sensor could simplify the ship monitoring system, make the maintenance easier and improve reliability of ship monitoring greatly.
A New Model for Forecasting the Locations of Next Crime
Authors: Wan Jia Di , Zhang Yuan Biao , Yu Wen Jing , He Chuan
Published: September 2010

The paper is aimed at forecasting the locations of next crime. Based on local demographic factors, geographic factors and environment psychological factors, it establishes a Multi-factor Evaluation Model. We then use an actual case (The Yorkshire Ripper case) for model testing, and get good test results.
Ear Recognition Based on Supervised Learning Using Gabor Filters
Authors: Xiao Yong Liang , Zhu Shao Ping
Published: September 2010

In this paper, we introduce a new ear recognition approach including a feature extraction method and the recognition framework. Firstly, we use a supervised kernel neighborhood preserving projection to extract discriminately ear feature, then we use generalized locally nearest neighbor classifier to recognize ear. Experimental results on USTB ear database show the effectiveness of our method.
A Dynamic Programming Model of the Coordination between Forest and Socio-Economy
Authors: Ye Tao
Published: September 2010

Based on the illustration of the importance of the coordination between forest and socio-economy, a dynamic programming model aimed at the coordination is created and the basic characters of the functions in the model are discussed. A solution under a simple and ideal situation is studied, which results in the equation of the economic yield when forest coordinates with socio-economy and several other conclusions.
Return Intervals Analysis of the Sunspot Time Series
Authors: Fan Jie , Li Wan Qing , Zhang Hong , Dong Ke Qiang
Published: September 2010

Rescaled range analysis (R/S) method is a scaling method commonly used for detecting the long-range correlations in many time series. The aim of this paper is to show that, using the rescaled range analysis on sunspot time series, how the threshold values q affects the correlations of the return intervals for events above a certain threshold q. We find that both the original records and the return intervals are long-range correlated.
On the Expected Discounted Penalty Function for a Risk Model with Thinning Process
Authors: Yu Wen Guang
Published: September 2010

This paper studies the expected discounted penalty function for a risk model in which the arrival of insurance policies is a Poisson process and the process of claim occurring is -thinning process. Using backward differential argument, we derive the integro-differential equation satisfied by the expected discounted penalty function when the stochastic discount interest process is perturbed by standard Wiener process and Poisson-Geometric process. Applications of the integral equation are given to the Laplace transform of the time of ruin, the deficit at ruin, the surplus immediately before ruin occurs. In some special cases with exponential distributions, closed form expressions for these quantities are obtained.
Research on Data Model of Electronic Medical Record Based on XML
Authors: Liu Lina , Cen Qin , Ji Mei , Chen Li Qiong
Published: September 2010

Comparing with the old medical record, EMR(Electronic Medical Record)has more advantages on morden society. While XML plays an important part in EMR, so people make no efforts to study the XML. There are two data models of XML, which are DTD and XML Schema .Firstly the paper introduces these two data models, then analysis advantages and disadvantages through an instance, finally draws the conclusion.
A Congestion Control Protocol in P2P Networks
Authors: Zhao Yong Xiang , Chen Chang Jia
Published: September 2010

Many of current P2P application tend to use UDP as their transport protocol. Since UDP does not provide congestion control mechanism, the developers of these applications have to decide how frequently to send UDP packet individually. It is necessary to provide a common congestion control protocol specially design for P2P networks. This paper proposes a protocol for such propose and use simulation to valid it
A Robust Map-Match Algorithm for DR Correction
Authors: Han Yong Qiang , Liu Zhi De , Chen Jia Bin
Published: September 2010

In this paper, a robust correction algorithm for Dead Reckoning (DR) navigation system is proposed based on digital map. The DR system here contains an IMU unit, in which 3 Ring Laser Gyros (RLG) and 3 accelerometers are consisted, providing azimuth angle, and an odometer that can provide mileage increament. An improved Map-Match algorithm is designed and implemented, which composes a “road correction” unit and a “road projection” unit based on geometry theory. To enhance the robustness of the system, a new communication protocol is designed. Based on the information provided by digital map, the DR system can not only corrects the position output, but also estimates the odometer scale factor error with a newly designed online calibration algorithm. Road test is conducted and the results have testified the effectiveness of the algorithm.
Asymptotic Analysis for Hyperbolic Equation with Neumann Condition
Authors: Cai Xin
Published: September 2010

The second-order hyperbolic equation with small parameter and Neumann con-
dition is considered. This kind of problem loses the boundary conditions both in x = 0 and
x = 1, while it also loses two initial boundary conditions in t = 0. The solution changes rapidly
near two boundary layers and one initial layer. Firstly, the asymptotic solution was studied.
The analytical solution was approximated by the degenerate solution and two boundary layer
functions and one initial layer function. Secondly, three transition points were presented ac-
cording to Shishkin’s idea. Non-equidistant mesh partitions both in x direction and t direction
were introduced. An effective computational method is given according to non-equidistant mesh
partitions. Finally, numerical experiment was given.
Effective Approximation for Elliptic Partial Differential Equation with Periodical Boundary Value Problem
Authors: Cai Xin
Published: September 2010

Elliptic partial differential equation with periodical boundary value problem was considered. The equation would degenerate to parabolic partial differential equation when small parameter tends to zero. This is a multi-scale problem. Firstly, the property of boundary layer was discussed. Secondly, the boundary layer function was presented. The smooth component was constructed according to the boundary layer function. Thirdly, finite difference scheme for the smooth component is proposed according to transition point in time direction. Finally, experiment was proposed to illustrate that our presented method is an effective computational method.
Aerodynamic Simulation and Analysis for Biomimetic Flapping-Wing Robot
Authors: Xu Jin , Chen Liang , Sun Wei
Published: September 2010

As a new conceptual micro air vehicle, biomimetic flapping-wing robots have the advantages of small sizes, light weights, high maneuverability, and perfect aerodynamic performance. Flapping-wing robot can produce more effective aerodynamic force than traditional fixed-wing or rotary-wing aircrafts. Unsteady aerodynamics at low Reynolds number is the main theory applied to micro air vehicle analysis. In this paper, the flight parameters for a flapping-wing robot are designed with geometric similarity firstly. Then an improved aerodynamic model with optimized parameters is established. Lastly, some simulation and analysis are presented to illustrate and verify the feasibility and effectiveness of the models.
Multi-Axle Moving Train Loads Identification by Using Fuzzy Pattern Recognition Technique
Authors: Wang Yi , Qu Wei Lian
Published: September 2010

Identification of multi-axle moving loads on bridge is very important for bridge design, construction, and maintenance in engineering field. It is complicated and time consuming to identify the multi-axle moving train loads with general identification methods and far away from practical practice. Based on the theory of fuzzy pattern recognition, the fuzzy pattern recognition method for multi-axle moving train loads identification on bridge is presented in this paper. The multi-axle moving loads pattern library on a simply supported bridge is established with numerical methods. Effect of measurement noise on the proposed method is investigated in three situations. The results show that the proposed identification method has a certain resistance to measurement noise and can realize moving train loads identification with high accuracy.
Experimental Study on Integrated Performance for Flower Baffle Heat Exchanger’s Distance between Two Flower Baffles
Authors: Lai Xue Jiang , Li Rui , Dai Yong , Huang Su Yi
Published: September 2010

Flower baffle heat exchanger’s structure and design idea is introduced. Flower baffle heat exchanger has unique support structure. It can both enhance the efficiency of the heat transfer and reduce the pressure drop. Through the experimental study, under the same shell side flow, the heat transfer coefficient K which the distance between two flower baffles is 134mm is higher 3%~9% than the one of which the distances between two flower baffles are 163mm,123mm. The heat transfer coefficient K which the distance between two flower baffles is 147mm is close to the one of which the distances between two flower baffles is 134mm. The shell volume flow V is higher, the incremental quantity of heat transfer coefficient K is more. The integrated performance K/Δp of flower baffle heat exchanger which the distance between two flower baffles is 134mm is higher 3%~9% than the one of which the distances between two flower baffles are 163mm,123mm. Therefore, the best distance between two flower baffles exists between 134mm~147mm this experiment.
The Study on the Residual Stresses of Circular Sawblades with Spherical Surface Pressed Many Spots
Authors: Mo Qiu Yun , Zhang Zhan Kuan , Li Hao
Published: September 2010

This paper is a comprehensive analysis about circular saws exerted the inertia stresses, thermal stresses and residual stresses inducted roll and hammer tensioning in working procedures. And analyze the weaknesses and the advantages of two methods of roll tensioning and hammer tensioning. In order to take advantages to compensate the weaknesses to bring forward a new tensioning method compressed many areas i.e. the tensioning spots compressed by using the roll-head whose surface is spherical, cylindrical or cone. The X-ray stress-checking instrument is used to test the residual stresses in the tensioned circular sawblades compressed on many spots. The result explains the stress distribution curve is very ideal and the residual stresses by tensioning almost offset the total inertia and thermal stresses inducted in the work. This explains it is a new circular tensioning method with developing value by compressing many spots. It exists in certain residual stresses on the rim of the sawblade’s central bore, outside and the areas near the slot bore because of the influence of the machine processes.
Visualization Experiment with PIV and Analysis of Flow Field in Hydrodynamic Coupling
Authors: Lu Xiu Quan , Ma Wen Xing , Fan Li Dan , Cai Bo Sen
Published: September 2010

In order to study the complex flow state of the internal flow field while the hydrodynamic coupling is under working conditions, the two dimensions PIV technique of the modern testing technology is adopted to test and analyze typical working conditions of hydrodynamic coupling. According to the experimental results, the internal flow field of the typical working conditions is analyzed and compared in qualitative way. The research of this paper has guiding significance for the hydrodynamic coupling design.
Vehicles Aerodynamics while Crossing each other on Road Based on Computational Fluid Dynamics
Authors: Zhang Zhe , Zhang Ying Chao , Li Jie
Published: September 2010

When vehicles run on road, they will be overtaken, cross by other vehicles or be impacted by crosswind. The other events of overtaking and in crosswind were investigated more deeply. A few of paper report the state of the research on this problem. Until now there are no any wind tunnel and road tests to study on road vehicle aerodynamics while crossing each other. Some numerical simulations were carried out by adopting technology of sliding interface and moving mesh. The method of numerical simulations was narrated in detail. The transient process of vehicles crossing each other was realized. Then the trends of aerodynamic coefficients changing were obtained from the flow field of simulation results. The quantificational changing of vehicles aerodynamic coefficients was obtained when they cross each other. The vehicles are sedan and coach. The simulation results indicated that the all aerodynamic coefficients of two vehicles changed large. The aerodynamic force was important to the vehicles’ handling stability when they cross each other.
The Study on Fractal Damage of Rock under Hydraulic Fracturing Basing on Conversation of Energy
Authors: Zhao Wan Chun , Wang Ting Ting , Ju Guo Shuai , Zheng Da Chun
Published: September 2010

The fractal characteristics is Considered in rock porosity structure, and rock damage variable is defined by reduced amount pore number whose radius is greater than R during arbitrary fracturing stage. Assuming that the micro-fracturing process of evolution cracks meets Logistic bifurcation standard model, according to energy conservation principle, the model of hydraulic fracturing of rock damage and infiltration of evolution is established based on the porosity fractal damage theory. And then the hydraulic fracturing rock evolution model is built. Taking one well of any oil field as the example, rock damage variable, porosity evolution during fracturing process are calculated, which shows that the results are reasonable and accurate.
An Analysis of the Influence of Rolling-Cut Shears with Different Eccentric Magnitude on the Locus of Upper Blade
Authors: Sun Deng Yue , Zhao Yang , Yan Yan Jun , Dong Chun Guang , Wang Jun
Published: September 2010

The paper will give a kinematic analysis of 4300mm Rolling-cut shears by Solidworks software, and compare movement locus of upper blade with different eccentric magnitude and offset in the initial phase, to arrive at inherent laws in their different states, and try to present the range of optimal eccentric magnitude and offset.
Boundary Lubrication Model under Square Surface Contact Condition
Authors: Wang Wei Zu , Wang Liu Yi , Zhang Zeng Xue , Chen Hai Bo
Published: September 2010

The contact temperature of the frictional surfaces under boundary lubrication in square surface contact is calculated according to classic heat conduction theories. The friction coefficient of boundary lubrication is expressed with the friction coefficient of boundary film and direct contact. Then, a model is developed based on the relationship of adsorption heat, friction coefficient and contact temperature. The model is used to solve a sample question. The results illuminate that when the applied load is relatively small, the friction coefficient keeps at a stable small value with the variation of the sliding speed and the load. However, when the load reaches a certain value, the increase of the sliding speed or the normal load both leads to the increase of the friction coefficient. The friction coefficient is also increases with the increase of the contact temperature. The relative deficiency of oil, which indicates the proportion of the true contact area to mean contact area, has almost the same variation trend of the friction coefficient.
Study on High-Speed Lateral Stability of Car-Trailer Combination
Authors: Zhou Shu Wen , Zhang Si Qi , Zhao Guang Yao
Published: September 2010

Since the handling behaviour of car-trailer combination is more complex and less predictable than that of non-articulated vehicles, the drivers may lose control of the vehicle in some hasty steering maneuvers. The kinematics of car-trailer combination has been analyzed with a 3 DOF model. A modified Vehicle Dynamics Control system was designed to improve the lateral stability of the trailer. The dynamics simulation for lateral stability of car-trailer combination has been performed on the multi-body model. The results show that the lateral stability of car-trailer combination, including yaw rate and roll angle has been improved with the modified Vehicle Dynamics Control system.
Creep and Relaxation of Thermo-Viscoelasticity Using the Symplectic System Method
Authors: Zhang Wei Xiang , Yuan Fang
Published: September 2010

This paper discusses thermo-viscoelastic problems using the symplectic system method. With the aid of the symplectic character and the Laplace integral transformation, all general solutions of the homogeneous equation are obtained directly via zero eigensolutions and their Jordan forms of the corresponding symplectic dual equations. The special solution of the non-homogeneous equations are given by applying the the adjoint symplectic relation between the eigensolutions. Examples show the results of the direct symplectic method, and reveal the creep and relaxation properties of the time dependent viscoelastic materials.
Effect of Prestrain on Fracture Toughness of Welded Joint
Authors: Lu Qing Hua , Yu Zhi Shui , Chen Li Gong
Published: September 2010

The tension, Charpy notch impact and fracture toughness tests on structural steels Q235B and Q345 were carried out under different prestrains. Ductile to brittle transition curves are investigated using Charpy impact tests. The results indicate that the prestrain decreases the impact toughness of both base metal (BM) and weld metal (WM); and increases the ductile-brittle transition temperature as well as the risk of fracture. The prestrain is also found to have a more significant effect in a less ductile material. River marking, the characteristic of cleavage fracture, is observed in the Q235B WM specimens 10% prestrain conditions at 0°C. The fracture surfaces of Q345 WM specimens are characterized by dimple-like structures. The depth of these dimples is decreased under prestrain applied before welding. The CTOD-prestrain curves are obtained using Boltzmann relation.
Seismic Safety Evaluation of High Arch Dams Using Concrete Damage Theory
Authors: Niu Zhi Guo , Lu Jun , You Ri
Published: September 2010

To reasonably evaluate the seismic behavior of high arch dams, a damage plasticity model is adopted to simulate the dynamic nonlinear behavior of dam concrete for a hydropower station. Combining with the viscous-spring boundary and compressibility reservoir model, the maximum principal stress on upstream and downstream surfaces is obtained. The results show that the effects of material nonlinearity damage on the dynamic response of the arch dam are significant under earthquake load.
The Rock Mass Damage Fragment Distribution of the Fracture for the Wells with Broken Casing
Authors: Ai Chi , Zhang Ji Nan , Liu Guo Yong
Published: September 2010

After the casing broken, under the action of internal and external pressure, the sidewall rock surrounding the fracture occurred damage and fragmentation and entered into the wellbore by the fracture, accumulation in the borehole. Due to the different sizes of rock mass damage fragmentation, formulation program for milling and sandwashing in workover was largely affected, the paper was started from velocity of elastic longitudinal wave, based on probability theory and the application of fractal geometry theory, a new calculation method of rock fractal dimension was established. The traditional theory of rock mass damage fragment distribution was enriched. The rock mass damage fragment distribution was more easily and more efficiently forecasted. And the reference frame of parameter design for casing-damaged well work over was provided, and guiding site-operation was quickly and effectively constructed.
Damage Detection for Simply Supported Beams Using Mid-Span Displacement Indicator
Authors: Zhang S.J. , Ma Z.J.
Published: September 2010

This paper investigates the detection of damage for simply supported beams to ensure their safety. Based on the analysis of possible kinds of damage may occur, this paper presents a new approach which relies on the fact that any change in local stiffness caused by damage can be reflected by the change of mid-span displacement between the intact and damaged beams. Direct relationship between the change in local stiffness and the measured mid-span displacement values is developed. This approach can identify the geometric locations of damage and then inspection means are used as a complement to find the real damage phenomena within the obtained small region. A numerical example is given to illustrate the feasibility and the effectiveness of the approach. The novel content offered by authors provides a simple, convenient, cost-effective, and nondestructive damage detection approach for simply supported beams.
A Pseudo Excitation Method for Vehicle Vibration Analysis in Uneven Speeds
Authors: Zhang Li Ping , Guo Li Xin
Published: September 2010

The vehicle riding comfort has become one of important factors of vehicle quality and receives more increasing attention. The driving smoothness of vehicles has immediate influence on the riding comfort of vehicles. In this study, the mechanical model and mathematics model of the 1/2 five degrees of freedom of a vehicle were established, as well as the pseudo- excitation model of road conditions for the front wheel and the rear wheel. By the pseudo- excitation method, the equations of the transient response and the power spectral density were established. After numerical simulation to vehicle vibration response of uneven driving, the results show that the pseudo- excitation method is more convenient than the traditional method and effectively solves the smoothness computation of vehicles while the pseudo- excitation method is used to analyze vehicle vibration under non-stationary random vibration.
Experiment and Simulation of Electromagnetic Stiffness for Stepper Motor
Authors: Yang Yan Long , Cheng Wei , Wu Shi Jian , Wang Gui You
Published: September 2010

Electromagnetic stiffness is an important parameter of stepper motor. It impacts obviously on system natural frequency. In this paper, the torsional vibration mechanism of stepper motor rotor caused by electromagnetic stiffness is studied and the mathematical formula for electromagnetic stiffness is established derived from stepper motor mathematical models. We simulate and experiment on stepper motor with parameters in the paper. Simulation value and experiment value of the electromagnetic stiffness are consistence with the numerical one. So it verifies the existence of electromagnetic stiffness, which provides a basis for researching on frequency variation of motor dragging flexible load.
Living Load Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges
Authors: Wang Hui Li , Qin Si Feng , Huang Cai Liang , Ge Xiao Meng
Published: September 2010

Living load nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. A self-anchored cable-stayed suspension bridge with a main span of 800m is analyzed with linear theory, second-order theory and nonlinear theory respectively. The moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800m and the error is less than 6%.
Primary Resonance of the Current-Carrying Beam in Thermal-Magneto-Elasticity Field
Authors: Xi Xiao Yan , Yang Zhian , Meng Li Li , Zhu Chang Jian
Published: September 2010

On base of the electro-magneto-elastic theory and the theory of the bending vibration of the electric beam, nonlinear vibration equation of current-carrying beam subjected to thermal-magneto-elasticity field is studied. The Lorentz force and thermal force on the beam are derived. According to the method of multiple scales for nonlinear vibrations the approximation solution of the primary resonance of the system is obtained. Numerical analysis results show that the amplitude changed with the system parameters. With the decrease of magnetic intensity, the amplitude increases rapidly. The response curve occurs bending phenomenon and soft features is increased gradually. Increasing current, the amplitudes increase. With the decrease of temperature, the peak of response curves decrease. With the increase of temperature, natural frequency decreased. It is useful in practical engineering.
A Multi-Fault Diagnosis Method of Rolling Bearing Based on Wavelet-PCA and Fuzzy K-Nearest Neighbor
Authors: Chen Xiang Shun , Zeng Hu Biao , Li Zhi Xiong
Published: September 2010

Rolling bearings are widely used in various areas including aircraft, mining, manufacturing, and agriculture, etc. The breakdowns of the rotational machinery resulted from the rolling bearing failures account for 30%. It is therefore imperative to monitor the rolling bearing conditions in time in order to prevent the malfunctions of the plants. In the present paper is described a fault detection and diagnosis technique for rolling bearing multi-faults based on wavelet-principle component analysis (PCA) and fuzzy k-nearest neighbor (FKNN). In the diagnosis process, the wavelet analysis was firstly employed to decompose the vibration data of the rolling bearings under eight different operating conditions, and for each sample its energy of each sub-band was calculated to obtain the original feature space. Then, the PCA was used to reduce the dimensionality of the original feature vector and hence the most important features could be gotten. Lastly, the FKNN algorithm was employed in the pattern recognition to identify the conditions of the bearings of interest. The experimental results suggest that the sensitive fault features can be extracted efficiently after the wavelet-PCA processing, and the proposed diagnostic system is effective for the rolling bearing multi-fault diagnosis. In addition, the proposed method can achieve higher performance than that without PCA with respect to the classification rate.
Research on the Double-Drum Drive Power Balance of the Hemicycle Deep Trough Belt Conveyor
Authors: Deng Yong Sheng , Xiao Cheng Yong , Xiao Ping Yang , Sun Yu Xin
Published: September 2010

Under the same output torque of the drive system, the imbalanced degree formula of the motor power was inferred, which expressed with elastic deformation, drum diameter and motor external characteristics. The reason and the main influence factors to the motor power imbalance were analysed. The results show that the best choice of belt conveyor on multi-drum drive occasion is steel cord belt, and the first drum diameter should be slightly bigger than the second drum diameter, in order to make sure the distribution of motor power is relatively balanced.
The Analysis of Energy-Saving Mechanism of Hybrid Excavator
Authors: Wang Peng Yu , Wang Qing Nian , Zhang Qi Ming , Yang Sheng Qing
Published: September 2010

In this paper based on the model of hybrid excavator that established in the software environment of AMESim, a configuration design and modeling of the power system of the excavator were made，then the several hybrid power system modes and energy-saving mechanisms of hybrid excavator were simulated and analyzed, the energy-saving potentialities of various energy-saving ways were calculated, and a hybrid power configuration mode that suit for present hybrid excavator was put forward.
Gas-Solid Two-Phase Flow Simulation of Coaxial Powder Delivery Nozzle in Rapid Prototyping
Authors: Wang Zhi Jian , Shang Xiao Feng
Published: September 2010

Coaxial powder delivery nozzle plays an important role in metal part direct and rapid prototyping technology and the reasonable structure can ensure uniform and stable flow of metal powder. Gas-solid two-phase flow theory is considered to simulate outside flow field of carrying gas-type coaxial powder delivery nozzle. The physical and mathematical models are erected. FLUENT software is used to simulate the velocity distribution of gas and solid particle, the volume fraction distribution of particle and the focusing properties. The simulative results indicate that both the structure of coaxial powder delivery nozzle and inlet velocity affect the convergence of powder. When the metal powder is only driven by the carrying gas without the shield gas flow, the powder appears focusing and the focus is 8mm far from the nozzle exit, but the volume fraction at the focus is only 2.6 percent, which shows the convergence of powder is not good and the usage rate is not high. In the optimized structure the simulative results show that the powder flow is affected by the flow of shield gas. When the velocity of shield gas is 6m/s, the powder shows good convergence and the volume fraction of powder at the focus reaches 3.3 percent. The higher the velocity of shield gas is, the more uniformly the powder flows, but the volume fraction at the focus is slightly lower. It is obvious that the numerical simulation will benefit for coaxial nozzle designing and performance improving.
Fractal Application in Micro Rock Mechanics of Low-Permeability Oil Reservoirs and Its Relationship with Enlarging Producing Reserves by Gemini Surfactant Flooding
Authors: Wei Heng , Wei Lei , Yin Jian Hui , Yin Fu Ling , Liu Jun Han , Li Hou Hua , Wei Guo Qi , Liu Xian Gui , Liu Wei Dong
Published: September 2010

Low permeability oil reservoirs were usually considered low quality reserves. However, low permeability oil reservoirs account for more and more percent of the proven reserves year by year in China. Conventional methods for analyzing medium-hign permeability cores are not suitable to low-permeability cores. Based on fractal method and the mercury injection curve data, the fractal dimensions of the pore structures of low permeability oil reservoirs are different from those of medium-high permeability oil reservoirs. The fractal dimensions of the pore structures of low permeability oil reservoirs are less than 2. Low permeability oil reservoirs which were not able to be developed are able to be developed by gemini surfactant flooding. This helps more and more low quality reserves be turned into producing reserves.
Applying Support Vector Machines to Predict Tunnel Surrounding Rock Displacement
Authors: Yao Bao Zhen , Yang Cheng Yong , Yu Bing , Jia Fang Fang , Yu Bo
Published: September 2010

Displacement prediction of tunnel surrounding rock plays a significant role for safety estimation during tunnel construction. This paper presents an approach to use support vector machines (SVM) to predict tunnel surrounding rock displacement. A stepwise search is also introduced to optimize the parameters in SVM. The data of Fangtianchong tunnel is use to evaluate the proposed model. The comparison between artificial neural network (ANN) and SVM shows that SVM has a high-accuracy prediction than ANN. Results also show SVM seems to be a powerful tool for tunnel surrounding rock displacement prediction.
A Novel Control Algorithm Integrated RBFNN and Physical Model for Roller Kiln
Authors: Tang Liang , Gong Li Xiong , Yang Ming Zhong
Published: September 2010

This paper proposes a novel control strategy using an on-line dynamic switching mechanism for controlling the sintering process of ceramic roller kiln. The RBFNN is applied to extract key information such as temperature parameters and gas pressure, and send the prediction information to the controller of actuator. The mathematical model which based on physical and heat conduction theory is derived and the real-time controller scheme is designed to make the output temperature in the sintering area follow the temperature-curve accurately. To achieve excellent transient performance and steady-state response, an on-line switching mechanism is adopted to regulate the forecasting step size of the predictor appropriately according to the error between reference value and real temperature of the kiln. Additionally, this kind of method can control the temperature of kiln without accurate mathematical models for the kiln effectively. When the sintering operating condition is stable, it is a kind of effective control strategy for temperature of roller kiln.
Review on Deflection Compensation Methods for Machining of Thin-Walled Components
Authors: Chen Yue Ping , Gao Jian , Wu Li Feng
Published: September 2010

The deflection of thin-walled components during machining will seriously affect their machining accuracy and surface quality. This paper presents a state of art review for the research in error prediction and error compensation during machining of these components. Some key techniques, such as the overall scheme, the cutting stability, the machining force modeling methodologies, the machining deformation analysis methodologies based on FEA and NC compensation methodologies, are discussed. The problems which have been highlighted in the research papers are pointed out and some problems which should be further investigated are given.
The Research on Preparation and Machining Performance of Hard, High Strength and Tenacity Wax-Based Material
Authors: Han Cun Cang , Lin Shi Lan
Published: September 2010

This paper studies the additive influence on paraffin performance. Paraffin, synthetic wax, vegetable wax, rosin wax and other additives are blended according to certain proportion, and the mixture is modified by amidation process. The hard, high strength and tenacity wax-based material is produced, and its machining performance is studied. The result suggests that the mechanical properties of this material is better than paraffin, it possesses the properties of high hardness, high strength and high ductility and toughness. This material can meet the machining requirements, it is a kind of ideal substitute material for consuming steel in machining technical training. The production of this material can solve the high consumption and high cost problems in application.
Steel, one of the known mechanical cutting materials, is widely used as engineering material. But in particular usage, such as the processing technology of universal machine tool, the training of numerical control processing technology and so on, because the cutting workpiece is not used as a forced mechanical component, the steel, as a mechanical material, not only lead to a great waste of a lot of steel, but also lead to the higher wearing of tool and higher consumption of power, which is caused by cutting steel. All of these factors make the machining technology training have been in an operation of high-consumption and high-cost. In China, more than 1000,000 tons steel and more than a billion yuan will be consumed by all kinds of mechanical engineering training in institutions and the skills training for employees machinery manufacturing enterprise. So for construction of a economical society, it has a great significance to develop a substitute material with lower price of raw material and simple preparation equipment and technology, which has no harm to environment and can be recycled repeatedly, and has the same mechanical cutting performance with steel. At present, in foreign countries, the sample wax is produced for mechanical cutting, and in our country, the preparation methods of high hardness wax and the effect of additive on paraffin hardness are introduced by many documents[1-3]. However, the wax-based material for mechanical cutting is not contained in any relevant research. To this end, we carry out research in this area.
Numerical Simulation of Gas-Solid Coupling in Coal Face
Authors: Bing Liang , Ye Li
Published: September 2010

Gas accidents in coal face threaten the safety production. Studying on gas emission law could help us avoid. The gas-solid coupling models with different mining styles were built up. Simulation of stress-displacement-gas coupling was made by Flac3D, combining with the background of Lu Ning coal. Results shows: the longer blasting time is, the larger plastic failure zones are; with the same external loads, strains of coal are larger when considering gas-solid coupling effect, gas flow to the coal face easily. Gas pressure turns to be nonlinear along tunneling direction used blasting, the longer blasting time is, the smaller gas pressure is. The gas pressure turns to be linear 0~10m to coal face with mechanical. The greatest variation of displacement and gas pressure are 0~3m to coal face, gas emission mainly occurred here.
Numerical Modeling the Effect of Tool-Chip Friction in Orthogonal Cutting AISI4340
Authors: Xu Gang Tao , Li Yu Sheng
Published: September 2010

A thermo-elastic-plastic model using explicit finite element code ABAQUS 6.8 was developed to investigate the effect of tool-chip friction in orthogonal cutting AISI4340. A.L.E finite element model was presented and the Johnson-Cook plastic model was used to model the workpiece material which is suitable for modeling cases with high strain, strain rate, strain hardening, and non-linear properties. In this paper, three different friction coefficient values of 0.2, 0.3, 0.4 were considered to study the effect on Cutting temperature, cutting forces and cutting stress. The results told a clear understanding of the effect of friction coefficient in orthogonal metal cutting, and larger friction coefficient induced higher cutting temperature, bigger cutting forces and larger cutting stress.
Jamming and Wedging Analysis of Non-Rigid Assembly with Friction Contact
Authors: Xia Yan Chun , Bai Yue Wei , He Ya Fei
Published: September 2010

It is well known that the friction force can lead to the analysis complexity of the contact constraint model. Based on Coulomb’s frictional model and unilateral constraint model, non-rigid bodies’ compliant dynamic model was established. Considering the whole motion of the assembly system and elastic contact deformation caused by assembly forces, the nearly rigid contact analysis is proposed. Jamming and wedging must be avoided for successful robot assembly operation. Based on the compliant dynamic model the conditions for jamming and wedging are provided in the formulations of the constrained dynamic system of peg-in-hole insertion.
Surface Topography Predication in High-Speed End Milling of Flexible Milling System
Authors: Li Zhong Qun , Li Shuo , Zhou Ming
Published: September 2010

During milling operation, the cutting forces will induce vibrations on both the cutting tool and the workpiece, which will affect the topography of the machined surface. Based on the Z-map representation of the workpiece, an improved model is presented to predicate the 3D surface topography along with the dynamic cutting forces during an end milling operation. A numerical approach is employed to solve the differential equations governing the dynamics of the milling system. The impact of cutting parameters such as the feedrate, the axial depth of cut and the dynamic characteristic of milling system on the surface topography is investigated by simulation. The all above can provide some instructive directions to the manufacturing engineers in determining the optimal cutting conditions of an end milling operation.
Finite Element Simulation and Experiment of Chip Formation during High Speed Cutting of Hardened Steel
Authors: Duan Chun Zheng , Yu Hai Yang , Cai Yu Jun , Li Yuan Yuan
Published: September 2010

As an advanced manufacturing technology which has been developed rapidly in recent years, high speed machining is widely applied in many industries. The chip formation during high speed machining is a complicated material deformation and removing process. In research area of high speed machining, the prediction of chip morphology is a hot and difficult topic. A finite element method based on the software ABAOUS which involves Johnson-Cook material model and fracture criterion was used to simulate the serrated chip morphology and cutting force during high speed cutting of AISI 1045 hardened steel. The serrated chip morphology and cutting force were observed and measured by high speed cutting experiment of AISI 1045 hardened steel. The effects of rake angle on cutting force, sawtooth degree and space between sawteeth were discussed. The investigation indicates that the simulation results are consistent with the experiments and this finite element simulation method presented can be used to predict the chip morphology and cutting force accurately during high speed cutting of hardened steel.
Experimental Study on Compressive Property of Concrete Corroded by Seawater in Low-Temperate
Authors: Zhang Ying Zi , Fan Ying Fang , Li Hong Nan , Wu Xue Nan
Published: September 2010

In order to investigate the compressive property of the concrete corroded by seawater in low-temperature, compressive tests are conducted on concrete specimen, which are corroded by accelerated corrosion method. Artificial seawater solution (Major ions concentration are five times of yellow seawater), are applied as the corrosive medium in the laboratory. Uniaxial compressive mechanical properties of the concrete tests, including 60 prism concrete specimens, are carried out. The physical and mechanical properties (including surface, mass, compressive strength, elastic modulus et al) of concrete in the different corrosion degree are researched. Taking the strength degradation ratio and elastic modulus loss as damage index, effects of the corrosion solution on the property of corroded concrete are discussed in detail. Relationships between the damage index and corrosion state of specimens are achieved.
Numerical Simulation of the Casting Process with Coupled Thermal and Stress Field
Authors: Zhou Jian Qiang , Yang Fa Zhan , Li De Sheng
Published: September 2010

To understand the thermal distribution in a complex structure and high quality linkage casting, a mathematical model of temperature and stress field was established. Numerical simulation techniques was applied by using Procast software in the temperature and stress fields of solidification process, and the foundry defect such as old lap, misrun, shrinkage and dispersed shrinkage was predicted. The stress distribution and deformation in cooling process of casting were analyzed. The simulation results can supply a scientific foundation for foundry technology.
Effects of Electric Pulse Modification on As-Cast Texture of Pure Copper
Authors: Qi Jin Gang , Wang Jian Zhong , Liu Xing Jiang , Dai Shan
Published: September 2010

The modification of liquid metal by electric pulse (EP or EPM) is a novel method for improvement of solidification structure. In this study, the as-cast texture of EP-modified pure copper was investigated by using X-ray Schulz backscattered method. The experimental results show that the as-cast texture of EP-modified pure copper is dissimilar with that of the unmodified. The unmodified mainly exhibits a type of {110}<001> texture, and the maximum value of orientation density is 10.07, in the plane that parallel to the vertical section along the ingot axis, the <110> crystal direction has the most volume fraction of 27.18%; By contrast, the as-cast texture of EP-modified pure copper shows a typical type of {102}<001>, and the maximum value of orientation density is 12.88, at the same time, the corresponding <102> crystal direction changes to be the most volume fraction and its value is 22.82%. These facts indicate that the crystal orientation (texture) of solidification structure could be altered by EPM, and EPM technology would thus influence the following metal formability.
Liquid/Liquid Interfacial Polymerization to Fabricate Sulfonated Graphene/Polyaniline Nanocomposite for Supercapacitors
Authors: Hao Qing Li , Wang Hua Lan , Yang Xu Jie , Lu Lu De , Wang Xin
Published: September 2010

A novel method to fabricate sulfonated graphene/polyaniline nanocomposite (SGEP) was developed by liquid/liquid interfacial polymerization. Sulfonic acid functional group was grafted to graphene sheets as a macromolecular doping acid for the polymerization of PANI, consequently forming a SGEP nanocomposite. The component, structure and properties of SGEP were characterized by Fourier transform infrared spectrometer, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope and electrochemical test techniques. The electrochemical tests showed that the highest specific capacitance reached 763 F/g.
Thermoelectric Properties of C-Axis-Oriented Ca3Co4O9+δ Films Grown on MgO-Buffered Si (100) by PLD Technique
Authors: Zhang Xia , Chen Hong , Liao Qiu Hui , Li Xia
Published: September 2010

High-quality c-axis-oriented Ca3Co4O9+δ thin films have been grown directly on Si (100) wafers with inserting MgO buffer layers by pulsed-laser deposition (PLD). X-ray diffraction and scan electron microscopy show good crystallinity of the Ca3Co4O9+δ films. The resistivity and Seebeck coefficient of the Ca3Co4O9+δ thin films on Si (100) substrates are 9.8 mΩcm and 189 μV/K at the temperature of 500K, respectively, comparable to the single-crystal samples. This advance demonstrates the possibility of integrating the cobaltate-based high thermoelectric materials with the current state-of-the-art silicon technology for thermoelectricity-on-a-chip applications.