bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulation of Marine Propeller Hydrodynamic Performance in Uniform Inflow with Different Turbulence Models
Authors: Bennaya Mohamed , Gong Jing Feng , Hegaze Moutaz M. , Zhang Wen Ping
Published: August 2013

In general, marine propellers have complicated geometries and as a consequence complicated flow around propeller. The aim of this work is to find an appropriate method and assess the turbulence model to approach the open water hydrodynamic characteristics of the marine propellers. In this work, a numerical modeling using a finite volume commercial code (FVM) for different turbulence models has been applied on the well known conventional screw propeller DTRC P4119. The 3-D solid model of P4119 is established using pro/E software and for the mesh generation ANSYS-ICEM has been used. Steady Reynolds-Averaged Navier Stokes (RANS) simulations are accomplished using FLUENT software with unstructured mesh in the rotating computational domain and structured mesh for the rest of the domain. The open water performance coefficients, thrust (KT), torque (KQ) and efficiency (η) have been calculated and compared with available experimental data to assess the applicability of different turbulence models for the open water study of propeller. This paper shows that, the accuracy of the CFD based on RANS equations is dependent on the used turbulence model and the RNG K-epsilon turbulence model yields to provide the most accurate results. Also, all the turbulence models via FLUENT software behave the same behavior for the total span of the advance coefficient (J) with two types of result accuracy. All the turbulence models shows high accuracy at low advance coefficient and this accuracy decreases but with an acceptable error till it decreases suddenly at the maximum advance coefficient.
The Heater Size and Viscosity Effects on Thermal Bubble Growth and Dynamics after Departure
Authors: Hsu Li Chieh , Huang Wen Chou , Gao Guo Jhih , Chuang Kai Yu , Chen Ing Youn
Published: August 2013

A single bubble growth after boiling in square vertical tube is studied numerically to better understand bubble formation factors and as well as its moving behavior after departure. The effects of heating surface area and viscosity of fluid are investigate with nucleation time, bubble departure time, bubble dimension as well as boiling curve. The study indicate that the larger heating surface area, the smaller bubble departure diameter and higher nucleation frequency. The larger of viscosity of fluid, the smaller moving deviation from central axis after bubble departure and smaller deformation of the bubble.
The Large Customers' Direct Electricity Purchase Sequence Evaluation Model from Multiple Types of Generators
Authors: Hu Qing Hui , Tan Zhong Fu , Ju Li Wei , Chen Zhi Hong
Published: August 2013

Large customers direct electricity purchase mode is a new electricity purchase mode introduced in the electricity market reform. It can not only further explore the potential of electricity market, but also introduce the competition mechanism on the electricity sale side, perfect the price system to rationally allocate resources according to the price signal. Combined with chinas electricity market-oriented reforming direction, this paper learns from the abroad electricity direct purchase experience, relates the important and difficult issues in large customers direct electricity purchase and finally figure out the sequence of large users direct electricity purchase. Structurally,based on the analysis of the basic theory, it builds an evaluation indicator system of large customers direct electricity purchase from multiple types of power suppliers and further use entropy method to process consistently and dimensionless. Finally combines gray correlation degree with ideal point method to evaluate the sequence of direct electricity purchase.
Preparation and Characterization of Hydroxyapatite Whiskers
Authors: Cui Yong Shun , Yan Ting Ting , Wu Xiao Pei , Chen Qing Hua
Published: August 2013

Hydroxyapatite whiskers were prepared with diammonium hydrogen phosphate, calcium nitrate, nitric acid, sorbitol, HAP seed and carbamide by hydrothermal homogeneous precipitation. The HAP seeds served as whiskers nuclei and sorbitol served as template. The prepared hydroxyapatite whiskers were characterized by XRD,SEM and FTIR. It was indicated that hydroxyapatite whiskers with high crystallinity grew alone Z axis with carbonated trend, and the appearance of HAP was smooth, less magazine and no reunion, the length-diameter ratio of the whiskers was in range of 125-8 with the average is 32.78.
Dynamic Fracture Toughness: Critical Review of Materials and Developments
Authors: Javed Raja Ahsan , Zhu Shi Fan , Farid Muhammad
Published: August 2013

For design to be more safe, dynamic fracture toughness (DFT) of material needs to be determined. Compared to static loading, dynamic loading procedures are not well established. Calculation of DFT is complicated and costly. Failure process of structures is greatly influenced by dynamic loading. In the past only steel and cast iron were employed for structure design purposes but now many new materials such as (a) composite, (b) alloys (titanium, magnesium), (c) ceramic, (d) concrete, and (e) brittle materials are being used. DFT calculations of materials under dynamic loading have resulted in new theories and experimental techniques. In this paper a critical review of the developments for the calculation of DFT for the materials is presented.
Study on Manufacturing Technology of High-Strength Composite Board
Authors: Su Shao Xing , Dong Ling Jiao
Published: August 2013

This article conducts research on the structure of board and the complete set of equipment development technology. It designs and develops new composite structural design solution and process route. In turn, it develops automatic and smart complete set of equipment, which can produce new high strength composite board. The board combines the advantages of corrugated fiberboard and honeycomb cardboard, so it has broad application prospects and a huge market potential.
Study on Grinding Burn in High Efficiency Deep Grinding
Authors: Zhang Xing Quan , Chen Liu San , Li Huan , Sh Jian Ping , Zuo Li Sheng , Zheng Ru , Chen Wei
Published: August 2013

The high efficiency deep grinding is widely used in manufacturing. The experiments were carried out to study on the high speed deep grinding force and grinding burn and cracks in grinding 40Cr steel specimen with Al2O3 wheel. The experimental studies demonstrate that the grinding force increases with the grinding layer depth. The trail of grinding on space surface is blurred progressively, the surface topography deteriorates gradually. When the depth of grinding increases to the certain value, grinding burn appears, and micro-cracks emerge. Selecting the optimization parameter in high speed deep grinding can avoid the grinding burn and grinding cracks.
Design of a High Power Programmable Intelligent Switch
Authors: Liu Bai Fen , Gao Ying
Published: August 2013

Based on the need to develop and test the products, a single phase DSP­based programmable AC power supply is designed. The power supply is capable of providing a stable AC voltage with adjustable amplitude and frequency over a wide range. Moreover, it can generate various high quality and low frequency arbitrary waveforms. Because of the advantages above, it will have great value in practice and a promising future in testing field. The main circuit of the power supply is to use rectifier and filter to make 220V AC voltage become steady DC voltage firstly. Then the inverter and the LC LPF are employed to produce the AC voltage which is required in the test system. The key part of the inverter is phase shift full bridge.
Adaptive Robust Control of a Class of Uncertain Nonlinear Systems Based on Backstepping
Authors: Zhao Hai Bo , Zhu Yun Guo
Published: August 2013

Aiming at the control of a class of bounded disturbance uncertain nonlinear systems,we applied robust control and backstepping control,introduced the concept of virtual control quantity,chose Lyapunov function through stepwise recursion,offered the adaptive law of parameters estimate,designed an adaptive controller with state feedback in the premise of unknown uncertain parameters in the systems, and analyzed its stability. Compared with the conventional PID control in simulation results, the designed controller has the better robustness of the system parameter uncertainty and bounded disturbances, and can ensure the entire closed-loop system is globally asymptotically stable, thus verifying the effectiveness of the proposed control strategy.
Research of the Precision Positioning Method for Electric Locomotive Automatic Control System
Authors: Lv Yan , Wang Hui Hui , Wang Xue Jun , Tao Xue Heng , Yang Ji Xin
Published: August 2013

The operation control of coke oven electric locomotive is an essential component of automatic control of coking manufacture. It is the main problem that coking enterprises should deal with in order to ensure the safety of production. In order to change and improve the actuality of manual driving, low positioning precision, high labor intensity and low producing efficiency, this paper proposes a practical and reliable automatic control scheme of electric locomotive based on successful experiences domestic and oversea.This scheme solves the key problem of electric locomotive automatic control-precision positioning, which containes a three-laser contraposition sensor and a positioning and lightproof piece used to ensure the accuracy of parking position detection, and a segmented deceleration control method used to ensure the automatism of parking brake. According to calculations and analysis, it is shown that the scheme could meet the system precision positioning requirements.
A Combined Reverse Fourier Set-Up for Laser Particle Size Measurement
Authors: Liu Wei Sheng , Liu Cui Cui , Li Chun Yu , Wei Yong Jie
Published: August 2013

A combined reverse Fourier set-up was presented on Fresnel diffraction theory. The set-up was used to measure particle size distribution with laser. A particle sample is set back of a lens. A first detector array is set in the focus plane of the lens. A second lens and a second detector array are set behind the first detector and the combined focus plane of the two lenses in turn. Thus the measurable size range at on sampling is enlarged. Experimental results on some latex samples by the prototype show that the relative errors are less than 6%.
A New Binocular Vision Stereo Matching Algorithm
Authors: Zhang Hui , Zhang Ling Tao , Wang Li
Published: August 2013

With the shortcomings of the large data amount and long time consuming in the conventional binocular vision stereo matching algorithm, a new fast stereo matching algorithm is presented in this paper. It is fast computed based on the line moments and angle vector .Firstly, the method detects image edge using canny operator, and finds the target objects according line moments, then the object contours feature points are extracted. Finally, using angle vector to realize the corresponding pixel matching in the left and right image .The algorithm effectively reduces the computational complexity, computational cost is decreased greatly. The experimental results show that the algorithm is possible and valid.
Detection and Control of Flexible Peristaltic Pipeline Robot in Elbow
Authors: Zhang Xin Xing , Zhang Yan Heng , Sun Han Xu , Nian Si Cheng
Published: August 2013

In order to make the peristaltic pipeline robot go through elbow quickly and efficiently, a multi-sensor information fusion algorithm based on relation matrix and fuzzy logic control is proposed. In this method, relation matrix is adopted to fuse the information from ultrasonic sensors and infrared sensors, while fuzzy neural network is employed to make walking strategy and remove obstructions. Simulation and platform testing are designed to verify the effectiveness of this method. The test results show that this method can significantly improve distance measuring accuracy and walking efficiency.
The Optimized Terminal Transport Organization of the Small Pieces of Cargo in CRE
Authors: Li Yina , Zhu Xiao Ning
Published: August 2013

The thesis finds the bottleneck restricting the efficiency of enterprise operational from capacity allocation of the small pieces cargos terminal transportation in CRE. The transport organization is optimized by the merge of pickup and delivery. And the use of mobile-cars strengthens the time limit of express service program. On this basis, the optimization of the transport organization is proposed: First, it builds the model and designs algorithms to get the path planning of pickup and delivery. Then combined with the reality factor, it completes timely dispatching command. At last, to prove the feasibility, it uses the optimized organization of terminal transport on a real case, and gets a better result with the total working time reduced by 30%.
Aspects on the Calculus and Construction of Translation Modules in the Mechanical Structure of an Industrial Robot Possessing Four Degrees of Freedom
Authors: Petrişor Silviu Mihai , Bârsan Ghiţă
Published: August 2013

The authors of this paper wish to highlight elements specific to the dynamic calculus, the concept, optimal design and assembly of translation modules in an industrial robot architecture of serial-modular construction, a structure which possesses in its kinematic chain structure four degrees of freedom. Based on a rigorous dynamic study conducted on the mechanical structure of the TTRT type industrial robot, modelling performed using Lagrangian formalism, and, taking into account the organological design elements that are part of the translation modules (the module attached to the robotic base - MTB Sil, the module in the vertical robotic arm MTV Sil, and the module in the mechanical structure of the horizontal robotic arm - MT Sil), the authors propose an energetic method of constructive optimization of the mechatronics system, according to which, translation modules can be arranged by applying the principle of interchangeable modularity so that energy consumption be minimum and not intervene on their organology. The paper highlights the dynamic-organological algorithm proposed in order to calculate motor moments and, hence, the selection of the DC servomotors necessary for setting the translation movable systems into service.
Contrasting Hot & Cold Testing Technique’s for I.C Engine’s
Authors: Khurana Ankit
Published: August 2013

It is imperative to test the functionality of an engine prior to installing in a vehicle. A hot test system is a 100% production test used to check all the engine operating parameters as they would function real-time in an actual vehicle whereas a cold test consists of a leak test, which includes the testing of all cavities and systems that must not leak, such as oil, water, fuel and air. The second feature of a cold test procedure is dynamic cold testing; where all engine functions are tested while the engine is driven by an electric motor at various speeds. In this study, co-relation is drawn between both the techniques with the present fault finding methods in cold testing and its subsequent enhancements which leads to refining the manufacturing or assembly processes.
Optimal Balancing of a 3-RPS Robot Manipulator Using Genetic Algorithm
Authors: Javaherchi Hossein , Ghaemi Osgouie Kambiz , Akbar Khayyat Amir Ali
Published: August 2013

Optimal balancing is a very important issue in mechanism design and has only recently been introduced to the designing step of robotic mechanisms. In creating the best robot design, the optimal balancing plays a vital role because it reduces the required motor power. To have a more-effective control system, it is very important to eliminate or significantly reduce the gravity load especially at the actuated joints. Tackling of a balancing problem with these objectives, leads to an optimization problem. This paper aims to describe the use of conventional and evolutionary optimization techniques for a 3-RPS parallel manipulator, using Genetic Algorithm (GA). To this end, it is required to find the desired weight for the links, to minimize the force at the actuators. At first the direct and inverse kinematic and dynamic analyses are performed, and then the optimum weight of the robot will be obtained. Afterwards, the optimization model is improved by adding two new elements. Also, a comprehensive user-friendly general-purpose software package is introduced. The methods used in this article can be applied to obtain solutions for a wide range of similar problems without further simplifications.
Analyzing and Control of Drive Mode in a Vibratory Ring Gyroscope
Authors: Lavasani Reza Esbati , Nikkhah Amirali
Published: August 2013

One of the challenges in MEMS era is dynamical modeling and control. This paper presents the analysis and control of drive mode of an 80 mm-thick, 1.1 mm in diameter high aspect-ratio (20:1) ring vibratory MEMS gyro. At first dynamic model of MEMS is derived through energy and Lagrange equations. Then state space equation is derived. Natural frequencies were derived by ABAQUS software and through equations. Frequency analysis was applied to analyze system and making comparison between two applied approaches in deriving frequencies. At last modified PID control was designed based on previous section results. We extracted results in presence of white noise to examine stability of the proposed controller. Consequently drive mode shows acceptable behavior through the applied PID controller. The aim is accomplished, though more advanced control can be applied to reduce uncertainty and compensate the noise in feedback to around zero.
SCILAB-Based Robust Control Design and Analysis for an Aerospace System
Authors: Kim Yoon Soo
Published: August 2013

This paper presents a SCILAB-based robust control and analysis example from aerospace engineering. The main motivation of this work is the lack of documentation for advanced users of SCILAB. Using the programming ideas developed for basic robust control and analysis in [1], a practical example from aerospace engineering is shown to demonstrate the merit of an open-source free software package, SCILAB.
Trajectory Design for the Transfer from the Lissajous Orbit of Sun-Earth System to Asteroids
Authors: Wang Ya Min , Qiao Dong , Cui Ping Yuan
Published: August 2013

This paper investigates the trajectory design issue for the transfer from the Lissajous orbit of CHANGE 2 probe to asteroids. First, an intersection search method, which is a general design method of low-energy transfer trajectories by searching the intersection of unstable and stable manifolds in the circular restricted three-body problem (CRTBP), is applied to produce the zero-cost flyby trajectories for the asteroid flyby missions of CHANGE 2 probe, and the simulation result shows that this method is invalid. Then, for this trajectories design issue, a perturbation method, which consists of a process of searching initial trajectories by applying velocity perturbations in the direction of unstable eigenvectors of the Lissajous orbit and a trajectory correction process with two-level differential correction, is proposed. Finally, the transfer opportunities between the Lissajous orbit of CHANGE 2 and asteroids Toutatis and 2010 JK1 are searched by the perturbation method. The results show that the method proposed in this paper can identify low-energy transfer trajectories for asteroid flyby missions of CHANGE 2. Moreover, this method provides a global understanding of the trend of impulsive maneuvers over the transfer date.
Effect of Forebody Strakes on Wing Rock Motion on a Generic Wing-Body Configuration Having Chine Forebody
Authors: Humayun Qureshi , Wang Yan Kui , Shi Wei , Li Qian
Published: August 2013

Experimental investigations are carried out to study the effect of forebody strakes on the wing rock motion of wing-body configuration. The cross section of forebody is of a chine shape. The chine shaped forebodies have advantage over slender nose forebodies as they generate more lift due to stronger forebody vortex. At higher angle of attack, the vortex asymmetry and asymmetric break-down can lead to un-commanded motions like roll divergence, wing rock etc. Of the two strake configuration studied, one configuration has exhibited the potential to delay and suppress the onset of wing rock, thus enhancing the angle-of-attack range where, no observation of un-commanded lateral motions is observed.
Thermo-Mechanical Behaviour of an Innovant Straw Lime Composite for Thermal Insulation Applications
Authors: Belayachi Naima , Bouasker Marwen , Hoxha Dashnor , Al-Mukhtar Muzahim
Published: August 2013

This paper presents an investigation on the use of new light-weight construction material, composed of lime, water and cereal straw fiber. Two types of fibers were used: wheat and barley straw. The influence of some parameters such as fiber types, binder types (lime and/ or lime-cement), fiber to binder ratio (F/B) and Water to Binder ratio (W/B) on the mechanical and thermal properties is studied. Compressive strength, thermal conductivity and density of the material were investigated. The results indicated that the thermal conductivity of the straw-lime composites decreased with increasing straw content. The result comparisons also revealed that the composite reinforced by wheat straw fibres has the highest compressive strength.
Investigation of Mechanical Properties and Microstructure of AA2024 and AA7075
Authors: Öksüz K.Emre , Bağirov Hanlar , Şimşir Mehmet , Karpuzoğlu Ceyhun , Özbölük Aykut , Demirhan Yusuf Z. , Bilgin Hayrettin U.
Published: August 2013

Aluminum alloys have been extensively used as structural material due to its high strength and damage-tolerance. Alloy 6061, 2024 and 7075 are engineered to be lightweight and strong,and their ease of formability allows complex shapes and drawn parts,which can then be further enhanced with heat treating. In this study is aimed to improve the mechanical properties of aluminum alloys by heat treatment.AA2024 and AA7075 were selected and each alone at T3 and T6 temper conditions has been studied respectively.For the mechanical properties of AA2024 and AA7075 alloyshardness, fatigue behavior, tensile test and charpy impact test with standard V notched specimens at RTand-5 °C were analysed in the present study. Microstructural characterization has been done using standard metallography.
Preparation of TiO2/Bio-Composite Film by Sol-Gel Method in VOCs Photocatalytic Degradation Process
Authors: Kreetachat Torpong , Kruenate Jittiporn , Suwannahong Kowit
Published: August 2013

Biodegradable of polylactic acid (PLA), polybutylene adipate-co-terephthalate (PBAT) and polybutylene succinate (PBS), which were biodegradable aliphatic polyesters, composite films were contained with titanium dioxide (TiO2) as a photocatalyst to evaluate the photocatalytic activity of bidegradable composite films for toluene removal. The synthesized TiO2 was prepared by sol-gel method between titanium isopropoxide with acetic acid. To form the anatase structure, it was calcined at 500°C. TiO2 were added to PLA/PBAT/PBS as a biopolymer blend at 0, 5 and 10 wt% .The TiO2/Bio-composite films were fabricated via blown film technique to produce 40 μm films. Photocatalytic activity efficiency of TiO2/Bio-composite films was performed in an annular closed system under UV light. Since the amount of TiO2 affected the efficiency of the photocatalytic activity, this work was mainly concentrated on the effort to embed the high amount of TiO2 in the biopolymer matrix. The developed photocatalyst was characterized by XRD, UV-Vis spectrophotometer and SEM. The SEM images revealed the high homogeneity of the deposition of TiO2 on the biopolymer matrix. The X-ray diffraction (XRD) ensures the deposition of TiO2 as crystalline anatase phase. In addition, the photocatalytic results shown that the toluene removal efficiencies increased with an increasing TiO2 dosages at 0 wt%, 5 wt%, and 10 wt% , respectively. As aspects, the photocatalytic degradation results showed the highest tolune photocatalytic degradation efficiency of 52.0% at 10 wt% TiO2 .
Simple Design of a Gravity-Independent Mass Balance
Authors: Kadri Shahrul , Mat Daud Anis Nazihah , Hashim Mohd Helmy , Rosli Jaafar , Asillam Mohd Fairos , Nurlisman Zulia Kurnia Dewi
Published: August 2013

The common mass balance has limited use in any gravitational condition. In this paper, we describe the simple design of a mass balance which is independent to the gravitational condition. Based on the Hookes Law, the balance is constructed by attaching the object being measured in the middle of two fixed end springs. The mass of the object is deducted from the frequency of the mechanical oscillation of the object. The performance of mass balance has been tested using four different mass loads (ranging from 15.28 g to 27.50 g) in three different gravitational conditions (0G, 1G and 2G) during parabolic flight. Our field testing resulted in the independency of the oscillation frequency of the mass on the gravitational conditions.
The Application of IRAs Optimizing Design in Vacuum Thermal Test
Authors: Sun Yu Wei , Yang Xiao Ning
Published: August 2013

The thermal vacuum environment simulation test is indispensible for the development of spacecrafts. And the simulation of the external heat flux exerted onto the spacecraft is one of the determining elements of the simulation test. In China, the infra-red simulation is a common method that used as simulation equipment of the external heat flux. The planar infra-red arrays is the most typical structure elements for planar spacecraft surface, but the margin effect of infra-red arrays influences the flux uniformity on heated surface severely. Based on Monte Carlo theory, some optimizing design guidelines had been drawn about planar infra-red arrays in past investigation. This paper introduces some testing and experiment that could confirm these guidelines, and these guidelines had been applied in some vacuum thermal tests of spacecrafts successfully.
The Study on Preparation of a B4C/Al Composite Fabricated by the Sponge Impregnant Method
Authors: Chen Yu Qiang , Li Peng , Sun Xiao Xiao , Liu Hai Sheng , Yang Jin Ru , Yao Lei , Wang Shu Yu
Published: August 2013

In this work, B4C porous ceramics reinforced alumium composite was fabricated by the sponge impregnant method and pressureless infiltration technique. The wettability of aluminum on B4C, the component and the wear resistance of the composite were studied .The result indicates that the infiltration temperature is determined 1200 centigrade and there are mainly Al, B4C, Al3BC , no AL4C3in the experimental composite, the wear resistance of B4C/AL composite is 25 to 30 times higher than that of the alumium.
Computer Extraction and Recognition Method Research on Weld Defect
Authors: Zhang Peng Lin , Wu Zheng Bin , Niu Xian Ming , Zhao Zhi Qiang
Published: August 2013

This paper carry out a kind of defect extraction method .Aiming at the weld image defect extraction accuracy is not high and defect feature selection is undeserved, thus affecting defect recognition rate is not high lead to falsely accused of miscarriage of justice on this condition.Based on image preprocessing to remove noise and strengthen the image, and then the image analysis so as to extract defect finally take defect marking defect feature parameter selection, in order to accurately identify defect.
Preparation and Characterization of Copolymer of Lactic Acid and N, N-Bis (hydroxyethyl) Glycin
Authors: Xie Ji Xing , Song Ying , Zhao Shan
Published: August 2013

Branched copolymer of lactic acid/bicine (N, N-bis (hydroxyethyl) glycin) was prepared directly by melt polycondensation from lactic acid and bicine. The branched structure of copolymer of lactic acid/bicine was characterized by 1H NMR and intrinsic viscosity. Although the molecular weigh of copolymer was lower than that of homopolymer of lactic acid, the hydroxyl number of the copolymer was higher than that of homopolymer. All the data indicated the molecule structure of copolymer was branched. Compared with homopolymer of lactic acid, the crystallinity of the branched copolymer decreased and the thermal stability increased.
Seismic Fragility Analysis of Mid-Story Isolation and Reduction Structures Based Two Directions
Authors: Chang Pei Ju
Published: August 2013

This study focus on derivation of such fragility curves using classic mid-story isolation and reduction structures (MIRS) in China metropolis. This study focus on derivation of such fragility curves using conventional industrial frames with masonry infill wall. A set of stochastic earthquake waves compatible with the response spectrum of China seismic code selected to represent the variability in ground motion. Dynamic inelastic time history analysis was used to analyze the random sample of structures. MIRS seismic capability of longitudinal and transversal orientation is different. Stochastic damage scatter diagrams based different seismic intensity index are obtained. Seismic fragility of longitudinal axis (Y axis) is larger than transversal axis (X axis) of frames under major earthquake obviously.
Validation of Bi-Material FEM Alveolar Bone Model
Authors: Liao Ching Tsun , Tseng Chwei Goong , Shih Kan Shan , Lee Pei Sheng
Published: August 2013

The purpose of this study was to verify the stresses induced by dental restoration on bi-material FEM alveolar bone model. Implanting induced stresses over the alveolar bone are studied during the past decades. With the improving computing technology, computer simulations with FEM( Finite Element Method) software are employed on investigating the stresses after the cure. An important issue about FEM calculations is the discretelized model. Single material bone model were adopt in the early stage studies. Due to the nature of human bone structure, the assumption of homogenous material over the bone is not an adequate one nowadays. Bi-material bone structure has become the mainstream of the numerical studies these years. The bones are modeled with a cancellous core surrounded by a dense cortical layer. Forces, stresses, deformations and strains are calculated by performing FEA on those digital bone models. However, the reliability of bi-material bones digital models is not verified. We built a bi-material prototype and an identical digital implanted bone model. Same boundary conditions and loads are applied on both models. The induced strains measured by strain gage agree with the computer calculated results well.
Bearing Fault Detection Based on Multi-Scale Laplace Wavelet Transform Spectrum
Authors: Wang Ya Ning
Published: August 2013

Laplace wavelet transform is self-adaptive to non-stationary and non-linear signal, which can detect the singularity characteristic of a signal precisely under strong background noise condition. A new method of bearing fault diagnosis based on multi-scale Laplace wavelet transform spectrum is proposed. The multi scale Laplace wavelet transform spectrum technique combines the advantages of Laplace wavelet transform, envelope spectrum and three dimensions color map into one integrated technique. The bearing fault vibration signal is firstly decomposed using Laplace wavelet transform. In the end, the multi scale Laplace wavelet transform spectrum is obtained and the characteristics of the bearing fault can be recognized according to the multi-scale Laplace wavelet transform spectrum. The proposed method has been verified by vibration signals obtained from rolling bearing with inner race fault.
Annealing Treatment of Ferroelectric Pb (Zr0.52Ti0.48)O3 Thin Films with La0.5Sr0.5CoO3 Buffer Layer
Authors: Guo Jie , Liu Wei , Man Shi Qing
Published: August 2013

Lead zirconium titanate Pb (Zr0.52Ti0.48)O3(PZT) thin films have been deposited on Pt/Ti/Si substrate by rf-magnetron sputtering. X rays diffraction revealed that at 600°C the PZT thin film had crystallized into ABO3perovskite phase. Degree of crystallization depended on annealing temperature. The perovskite grains were textured predominantly along the (110) direction. The grain size was about 140 nm and almost unchanged under different annealing temperature. With the annealing temperature increasing, the degree of crystallization was improved. La0.5Sr0.5CoO3(LSCO) thin film was grown on Pt/Ti/Si as buffer layer. PZT with LSCO buffer layer was intensively (110) preferred orientation and the morphology of PZT thin film changed greatly.
The Study on the Effects of Physical Factors on the Machinability of GDL-4 Tool Steel
Authors: Liang Yi Long , Gao Feng , Liu Jing
Published: August 2013

GDL-4 is a new kind of tool steel, but the machinability was the key factor for the application of it. In order to improve the machinability of GDL-4 tool steel, the factors influencing the machinability, such as the thermal property, work hardening exponent, carbides were studied comparing with M2 in this paper. The results show that under the same cutting condition, the thermal property is the key factor which makes the machinability of GDL-4 worse, and Si is the key element affecting the thermal property.
Mechanical Analyses of Advanced Multi-Chip Embedded Wafer Level Packages
Authors: Ho Siow Ling , Bu Lin , Sorono Dexter Velez , Chong Ser Choong , Chai Tai Chong , Zhang Xiao Wu
Published: August 2013

ncreasing functionality accompanied with device miniaturization in microelectronics has led to increased market demand for packages with small form factor. Over the years, embedded wafer level packaging (EWLP) has become an attractive option since it allows a reduction in package size and height. In the EWLP approach, the singulated dies are embedded within the molding compound through the wafer level compression molding process. For this study, critical mechanical challenges such as die shift and thermal cycling performance of a multi-chip embedded wafer level package (MCEWLP) are addressed through numerical modeling. For improved accuracy in die shift predictions, both mechanical effects and fluidic effects need to be taken into account. Mechanical effects account for around 75% of the die shift while fluidic effect contributes to the remaining 25%. It is shown that reducing the die size and the inclusion of UBM as a buffer layer can effectively increase the fatigue life of the packages.
Study on Trajectory Planning for Space Simulator Based on Minimum Acceleration Limitation
Authors: Bian Zhen Zhen , Li Hong Bo , He Yun , Xu Zhi Gang , Li Feng Sheng
Published: August 2013

Trajectory planning and simulation of docking tests on the ground for space simulator is one of key technologies to complete space docking mission. A new time-optimal trajectory planning algorithm is proposed based on minimum acceleration limitation. It is realized by searching maximum acceleration to obtain the best time according to PSO (particle swarm optimization). Through calling matlab script by LabView and capturing control set points, 3D CAD model is driven to verify the rationality of the trajectory planning algorithm and model design. The simulation results show that the simulator using the proposed algorithm can move smoothly and reliably meeting the experiment requirements.
Research on Simulating Structural Parameters' Impact on the Flow of Two Phases in Separator
Authors: Zhang Zhen Wei , Zhou Yong Sheng , Zhou Tao , Ji Xiang Lei
Published: August 2013

Adopting the RSM (Reynolds stress model) to conduct numerical simulation on gas phase flow field in bypass cyclone separators with two kinds of inlet structure, meanwhile, interphase coupling discrete model DPM is used to simulate the trace of particles in bypass cyclone separator. At last, the results demonstrate that the separating efficiency of separator B with a large length-width ratio inlet increased 1%~2% and the pressure drop is smaller when compared with separator A. A low average entering position and a short distance to the wall are helpful to improve the separating efficiency.
A Simple Method TOWARDS Decapping of the MEMS and CMOS Parts for CD Measurements and Failure Analysis
Authors: Wang Dan Dan , Lam Jeffrey , Mai Zhi Hong
Published: August 2013

Decapping is very important and essential for the MEMS failure analysis. Herein, we take a simple and environment friendly method to separate the device into MEMS and CMOS parts for CD measurements and failure analysis.
Influence of Metal Ions on β-D-glucosidase Activity, Growth and Astaxanthin Production of Xanthophyllomyces dendrorhous
Authors: Gong Lu Chan , Sun Yu Mei , Tang Wen Zhu , Chen Xiao Yi
Published: August 2013

Influence of Mn2+, Mg2+and Ca2+on β-D-glucosidase activity produced byXanthophyllomyces dendrorhouswas measured. The presence of Mn2+could increase the β-D-glucosidase activity and the change in cell morphology of obviously improves the cell growth and the astaxanthin biosynthesis. The cell biomass, the astaxanthin yield and the astaxanthin content in dry cell was reached to 3.65 g L-1, 3.06 mg L-1and 0.84 mg g-1at 72 h of fermentation respectively, which were higher than those in absence of Mn2+.
Effect of Dual-Phase Treatment on the Corrosion Behavior of Weathering Steel 09CuPCrNi
Authors: Zhang Chun Ling , Cai Da Yong , Zhang Ke Qin , Liao Bo
Published: August 2013

Dual-phase steels of 09CuPCrNi are prepared through intercritical quenching process. The influences of dual-phase treatment on the corrosion resistant property of the steels have been studied by electrochemical potentiodynamic tests and artificial salt spray tests. The results indicate that the corrosion behavior of DP780 and the as-received weathering steel in 5% sodium hydroxide, 3.5% sodium chloride, 5% sulphuric acid and various concentrations of hydrochloric acid solutions are identical, but dual-phase steels show least corrosion current as compared to the as-received steel. Rust layers of the as-received steel and DP780 are identical mainly consisting of three iron (hydr) oxides, goethite, akaganeite and lepidocrocite, and magnetite. Both the relative amount and morphology of phase constituents affect on the corrosion behavior of DP steels.
Phase Field Model for Grain Growth with Second-Phase Particles of Stick Shape
Authors: Zhou Wen Quan , Gao Ying Juna , Liu Yao , Luo Zhi Rong , Huang Chuang Gao
Published: August 2013

The phase field method was applied to study the effect of second-phase particles (SPP) with different geometric orientations and shapes on grain growth. The results show that, in the grain growth process, most of the spherical second-phase particles located at triple junctions, while the stick SPPs located at the grain boundaries along the grain boundary. The second-phase particles are of the strong pinning effect on grain boundary and the limiting grain radius can be expressed by Zener relations. In the condition of the second-phase particles area fraction and size remaining the same, the stick SPPs are of more effective pinning on grain growth than that for spherical SPPs, and the orientation of disk second-phase particles is also an influence factor for pinning effect. Stick second-phase particles with multiple orientations can make a better pining effect than those with only one orientation.
Modification of Retarder on Desulfurization Gypsum Wall Material
Authors: Niu Fu Sheng , Guo Ai Hong , Feng Xiang Wen , Meng Ying
Published: August 2013

In order to broaden the utilization of desulfurization gypsum in China and achieve the direct usage of desulfurization gypsum, in this paper, citric acid (CA), sodium citrate (SCA), sodium tripolyphosphate (STPP), Sodium hexametaphosphate (SP) were selected as retarder to modify desulfurization gypsum. The experiment results are as follows: the effect of SP, STPP, CA, SCA on desulfurization gypsum initial setting time is obvious; the turn is STPP> CA> SCA> SP; when the retarder dosage of STPP in desulfurization gypsum reaches 0.5%, the initial setting time can be extended to 210 min, the final setting time to 240min, which fully meets the demand of gypsum-site construction; inhibiting gypsum particles dissolution and preventing the growth of crystal nucleus are the fundamental reasons of STPP.
Study on Stressed MSFAC Attacked by Sodium Sulfate Solution
Authors: Li Feng Lan , Pan Li Yun , Guo Yan Wei
Published: August 2013

The paper introduces the experiments of sulfate attack on concrete under stress state. The concrete (MSFAC) was made with machine-made sand and fly ash. Before immersed in sodium solution with sulfate-ion concentration of 50000mg/L, the concrete beams with 100mm×100mm ×400mm dimension were in flexural tensile stress at levels of 20%, 40% and 60% of flexural tensile strength by the special designed stress devices. The sulfate-ion content in different erosion depths of concrete was measured at attack age of 30, 90, 180, 270, 360, 540 and 720 days by the chemical titration method. The results show that the apparent damage such as rough surface and cement past peeling off became more serious with the increasing tensile stress level and the prolongation of attack age, while much more obvious crystallization of gypsum was in surface cracks, the sulfate-ion content in the first layer near surface did not reflect the real status of concrete affected by tensile stress levels. The sulfate-ion contents of inside layers increased basically with the attack age at stress levels lower than 60% of tensile strength of concrete. In conditions of the experiment, the sulfate-ion content reduced when the attack age was longer than 540 days at the stress level of 60%.
Analysis on Coupling Degree among Crop Evapotranspiration, Effective Precipitation and Water Requirement of Corn on Southern Kerqin Sandy Land in China
Authors: Yang Ning , Sun Zhan Xiang , Zheng Jia Ming , Chi Dao Cai
Published: August 2013

Historical characteristics of crop evapotranspiration and irrigation requirement were the bases for determining the irrigation quota in local areas. Based on the trials of two years, crop evapotranspiration and crop coefficient of corn at monthly growth stages were determined and tested by soil water balance method in Fuxin of the southern kerqin sandy land. Using the weather data in Fuxin and Chaoyang from 1953 to 2009, estimated the coupling degree between crop water requirement of λ and apply irrigation water (ETaw) in growing season under three hydrologic years (P=25%,50%and75%).Under the humid year (25%),λ (0.756) in Fuxin was more suitable than Chaoyang (0.694),ETaw(95.5mm) in Fuxin was lower than Chaoyang (148.7mm);under the normal year (50%),λ(0.622) in Fuxin was close to Chaoyang (0.647),ETaw(180.4mm) in Fuxin was higher than Chaoyang (154mm); under droughty year (75%), λ (0.574) in Fuxin was also more suitable than Chaoyang (0.523),ETaw (204.8mm) in Fuxin was also lower than Chaoyang (245mm). The monthly change of λ and ETaw were sharping and influenced irrigation frequency in the growing season of humid and droughty year. The method and results can be further applied to agricultural water management study and guide irrigation in other same regions.
A Study of the Potential of CO2 Emission Reduction in China's Construction with Scenario Analysis
Authors: Gan Xue Hong , Wang Wei , Liu Shi Mei
Published: August 2013

The potential of CO2 emission reduction expected in the next 10 years of China's construction was studied with the the method of scenario analysis. The results showed that a total of 11.008 billion tons of CO2 would be reduced in chinas construction in the period of 2011-2020 and the contribution of CO2 emission reduction in China's construction to the potential target of CO2 emission reduction would be 48.07%.
An Investigation into the Effect of Design Parameters on Plasma Density in Dielectric Barrier Discharges (DBD)
Authors: Kim Jong Bong , Shin Myoung Soo
Published: August 2013

DBD (Dielectric Barrier Discharges) plasma is often used to clean the surface of semiconductors. The cleaning performance is affected by many process parameters such as electric voltage, the gas composition, gas speed, thickness of the dielectric wall, gap distance, and plasma duration time. In this study, the plasma density is predicted by a coupled simulation of gas flow, chemistry mixing and reaction, plasma generation, and electric field. A 13.56 MHz RF source is used to generate plasma. The effect of the dielectric thickness, the gap distance, the gas flow velocity, and electric voltage on the plasma density is investigated. It is shown that the plasma density increases as the dielectric thickness decreases, the gap distance increases, the gas velocity increases, and electric voltage increases, respectively. Finally, experiments are carried out to verify the analysis results.
Study on Vacuum Degree of Mechanical Cleaning System for Product Oil Tank
Authors: Li Xiao Hong , Zhang Guang Wei , Zhang Peng , Li Du Juan
Published: August 2013

A practical calculation method to determine the vacuum degree of a mechanical cleaning system is proposed mainly based on the theories of fluid mechanics. The system for cleaning of product oil tanks is operated relying on vacuum suction and simplified without heating section comparing with the system for crude oil tanks. It shows that the determination of vacuum level depends on two factors: to overcome the frictional resistance of suction tank's inlet pipes and to meet the net positive suction head (NPSH) required for a centrifugal pump fixed on outlet pipes of a suction tank. So, the higher and lower limits of vacuum degree can be found. The calculating method of vacuum degree is proved in a real system.
The Ventilation and Thermal Performance of the Patio Space in Shanghai Shikumen House
Authors: Luo Xiao Yu , Ge Jian , Cai Yi
Published: August 2013

Shanghai Shikumen house is a typical one of Chinese traditional residential architecture, which has a "two patios & one corridor" pattern adapting to the climate of Shanghai. In existing researches, most study of the thermal performance dwelling with courtyard is still qualitative. This research constructed the quantitative simulation of the " two patios & one corridor" pattern in Shanghai Shikumen house based on the mathematical model by the technical simulation software, and compared the above mode with the general courtyard house to test the advances of it. First of all, the research conduct a three-dimensional simulation analysis on the "two patios & one corridor" pattern and the general "Two patios" pattern. Then we compared the results of the wind environment of the two modes and found the "two patios & one corridor" mode has advances on ventilation. Secondly, we did thermal environment simulations of the rooms in the above two modes, and compared the analysis results of two modes. We found that the "two patios & one corridor" pattern did better in the room thermal. Finally, we hope this research can provide certain reference for the design of the sustainable residential architecture.
Structure Analysis of Large Steel Crude Oil Tank under the Planar Inclined Foundation
Authors: Wei Li Xin , Li Xiao Yan , Ji Da Wei
Published: August 2013

Large steel crude oil tanks constructed in soft foundations are susceptible to various types of settlement deflections. The most common type is planar inclined foundation. In this paper, the FEM is used for the study of deformation characteristic and stress distribution of large steel crude oil tank under the planar inclined foundation approaching to critical value. Results show that deformation characteristic of tank is unevenness; max stress in tank shell occurs in middle-low part of floating roof tank; the ultimate value of large steel crude oil tank under the planar inclined foundation is 0.89m.
A Self-Centering Seismic Design for Bridge with Pile-Cap Foundation
Authors: Yang Hao Lin , Dang Xin Zhi , Yuan Wan Cheng , Song De Qin
Published: August 2013

In this paper, an alternative aseismic system for bridge with pile-cap foundation called a separated pile-cap with proper material set in the gap layer was proposed. To simulate the system, a 3-dimensional finite element model for a continuous beam bridge was built. The seismic responses of the model, including behavior of the restrainer, moment at the bottom of the pier and pullout force of the piles with different restrainer lengths under 3 longitudinal artificial earthquake waves were analyzed. The results show that this system can reduce the seismic response significantly.