bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Modelling of Damage Progression in Single-Fiber Composite under Axial Tension
Authors: Yang Dong Min , Sheng Yong , Ye Jian Qiao , Tan Yuan Qiang , Jiang Sheng Qiang
Published: July 2011

Damage and failure of the fiber reinforced composites remain as a challenging research subject in the area of material science and engineering. In this study a novel particle assembly model is developed using two dimensional Discrete Element Method (DEM) for the purpose of simulating the damage and failure process of the single-fiber composite (SFC) under axial tension. Fiber (SiC) and matrix (Epoxy) are represented by particles bonded together through elastic parallel bonds which are calibrated by a series of numerical tests. The contacts between the fiber particles and matrix particles are directly accounted for the fiber/matrix interface which is represented by the contact softening model similar to the cohesive zone model (CZM) in the continuum mechanics. The single-fiber composite tensile test is carried out using the developed DEM model in order to evaluate the interactions between fiber breakage, interfacial debonding and matrix cracking. The numerical results have demonstrated the capability of the developed DEM model in simulating the entire failure process of each individual constituent of the single fiber composite. This study has also confirmed that the DEM model has unique advantages over the conventionally numerical models in terms of dealing with the evolution of microscopic damages in composite materials.
Optimization of Cutting Parameters Based on NC Machining Simulation
Authors: Wu Feng He , Zhao Feng Bing , Wu Feng Biao
Published: July 2011

A new method of NC machining simulation based optimization of cutting parameters is proposed. For the case of NC turning process, the method of extracting cutting parameters from NC programs is given. Based on the cutting theories, using linear weighted method, the multi-objective optimization function is constructed, and it is solved by complex method. The modification and storage strategy of parameters is also given. The application shows that the proposed method cannot only ensure the accuracy of NC code, but also provide the optimized cutting parameters under the constraints of appointed machine tools. It will be helpful for the optimization and intelligence of NC machining.
Implement of Intelligent Node for Vehicles Based on FlexRay Bus
Authors: Song Xue Hua , Lu Min , Yuan Yin Nan , Wang Hong , Zhang Yu Hua
Published: July 2011

The car can meet the high demand of the security and stability of the system by using FlexRay bus, while it also can implement optimization of the cost. The paper introduces a system of nodes’ communication based on FlexRay technology, and the system constructed two nodes which are composed of main processors, communication controllers and bus transceivers. The paper implements the transmission of data between main processors and communication controllers by EBI (external bus interface). It is succeed in implementing the communication process of receiving data and sending data among different nodes. The results show that the data completely correct while the data rate is 10Mbps. Therefore, it verifies the reliability and real-time communication of FlexRay. And it also means that the designed node will play a significant role in X-By-Wire.
Study on EDM Machining Technics of Polycrystalline Diamond Cutting Tool and PCD Cutting Tool’s Life
Authors: Jia Yun Hai , Li Jian Gang , Lu Xue Jun
Published: July 2011

The Samples of Polycrystalline Diamond (PCD) Cutting Tool Were Machined by Adjusting the Main Parameters of Electrical Discharge Machining (EDM). after the Machining, the Phases Were Analyzed by X-Ray Diffraction Analyzer and the Surface Layer Microstructure Were Observed by Scanning Electronic Microscope. the Fundamental Component of Machined PCD Cutting Tool Affected Layer Was Obtained and the Reason of Bring Affected Layer Was Analyzed. the Relationship Curves between Pulse Width, Working Electric Current and Depth Affected Layer, Surface Roughness Were Summarized. the Relationship between PCD Cutting Tools that Was Machined by EDM and Cutting Tool Flank Width, Workpiece Surface Roughness Were Analyed.The Results Showed that to Adjust Electical Discharge Machining Parameter, such as Pulse Width and Machining Electric Currents, Can Reduce the Depth of Affect Layer and Extend the Service Life of PCD Cutting Tool.These Researches Provide Valuable Test Reference for Drawing up Electrical Discharge Machining Technics of PCD Cutting Tool and Cutting Tool’s Life.
Study on the Tribology of the Cylinder and Piston Ring of the Vehicle Diesel with Surface Roughness and Lubrication Oil
Authors: Wei Hai Jun
Published: July 2011

The friction and abrasion of the cylinder and piston ring of the vehicle diesel has been carried on experimentation research using oil analysis technology in order to improve the diesel running-in quality and shorten the diesel running-in time, and analyze the defferent lubrication oil and surface roughness of the diesel piston ring in order to find a way to reducing abrasion of them. The experiment proves that the machining precision of the piston ring will affect evidently the oil film formed of between the piston ring and cylinder. The critical load forming oil film is inverse ratio Ra of the piston ring. It has been proved that it is a effective method to monitor the friction and abrasion of diesel piston ring.
Tribological Properties of Fe-Cu-MoS2 and Self-Lubricating Behaviors
Authors: Fu Chuan Qi , Sun Jun Cai , Wang Zhou
Published: July 2011

The Fe-Cu-MoS2composites with different adding amount of MoS2as lubricant were prepared by induction sintering method. Their mechanical and tribological properties from room temperature (RT) to 800°C were tested by universal testing machine and high temperature tribometer. The effects of amounts of MoS2, temperature, load and sliding distance on the friction and wear properties of composite were discussed. The structure of the composite was analyzed by XRD and worm surface morphologies were observed by SEM. It was found that MoS2was decomposed during the hot-press sintering process. Meanwhile, solid solution alloy of Mo and Fe, and sulfides were formed in composite, which were responsible for low-friction and high wear-resistance at elevated temperature, respectively. Hardness and anti-compress strength can be improved by adding 8 wt. % MoS2. The friction coefficients and wear rates of composites decrease with the increase of adding amount of MoS2until a critical value of 8 wt. %. The composite with 8 wt. % MoS2shows the optimum tribological properties over the temperature range of RT~800°C.
Simulation Analysis of the Oil Gathering and Transportation Process on Activity-Based Costing
Authors: Zhou Qing , Wang Li Yang
Published: July 2011

The oil gathering and transportation process is a key link in the oil industry. In this paper, to reengineer the ground works process of an oil production plant as an example of business process reengineering, the simulations of the oil and gas gathering and transportation process before and after the business process reengineering are conducted by using of SIMPROCESS software. While the utilization rate of various devices is compared with process simulation results to find the bottlenecks in processes, and a brief analysis of activities costs is presented.
Effect of Hardness upon Temperature Rise of Steel Specimens during Bending Fatigue by Using Infrared Thermography
Authors: Selek Murat , Sinan Şahin Ömer , Kahramanlı Şirzat
Published: July 2011

In this study, the effects of hardness on temperature increase of ST 37 steel during fatigue loading were investigated. Steel specimens are made of ST 37 steel and subjected to heat treatment to obtain different hardness. The specimens were subjected to reverse bending fatigue loading and the specimens were observed by using a infrared (IR) camera during the test. The obtained thermal images were recorded by FLIR E45 IR camera and then transferred to the image processing program developed by using MATLAB. Thus after image processing, thermal values used to detect the temperature rise of the surface of the steel specimen under fatigue loading were obtained. During the fatigue, the material is subjected to strain energy input which result in plastic or/and elastic deformation. This event results in an increase of temperature within material. The energy conservation requires that the generated heat shows itself as heat transfer by conduction, convection and radiation and internal energy increase. Besides, if the material has undergone plastic deformation, an additional term which accounts this effect should be included within energy conservation equation. In order to observe the effect of plastic deformation upon temperature increase of material, the ability of plastic deformation has been changed through the change of hardness and the thermal variations during fatigue has been investigated.
Investigation of Bending Fatigue of Composite Plates by Using Infrared Thermography
Authors: Sinan Şahin Ömer , Selek Murat , Kahramanlı Şirzat
Published: July 2011

In this study, the temperature rise of composite plates with a hole during fatigue loading was investigated. Woven glass/epoxy composite plates with eight plies were subjected to bending fatigue loading and materials were observed by using a thermal camera during the test. Previous works showed that a heat generation can form due to internal friction and damage formation. Therefore, a thermographic infrared imaging system was used to detect the temperature rise of composite specimens. During the tests, the thermal images of the specimens have been recorded by a thermal camera and then transferred to the image processing program which has been developed by using MATLAB. By using these thermal images, the spot temperatures of the specimen were obtained by using artificial neural networks. The obtained temperatures show local increase at places where the heat generation localized. These regions considered being the probable damage initiation sites. It is shown in this study that most probable damage initiation zones in the woven glass/epoxy composite material can be detected by using infrared thermography (IRT) approach prior to failure.
Monte Carlo Simulation of Reliability for Gear
Authors: Mo Wen Hui
Published: July 2011

Production errors, material properties and applied loads of the gear are stochastic .Considering the influence of these stochastic factors, reliability of gear is studied. The sensitivity analysis of random variable can reduce the number of random variables. Simulating random variables, a lot of samples are generated. Using the Monte Carlo simulation based on the sensitivity analysis, reliabilities of contacting fatigue strength and bending fatigue strength can be obtained. The Monte Carlo simulation approaches the accurate solution gradually with the increase of the number of simulations. The numerical example validates the proposed method.
An Evaluation of the Soil and Water Conservation Benefit in Nanzheng County
Authors: Hu Ming
Published: July 2011

According to some statistical surveys and data about the land from the year 1984 to 2004, here’s an analysis on where the financial investment in soil and water conservation comes and goes in tins district. In conclusion, after the actions in improving the soil and water, there’s an obvious decent in the flow rate of the channel’s interior diameter as well as the amount of soil erosion, a rise in vegetation coverage, and some improvement in ecological environment together with a great improvement to the natives’ living standard.
The Application of Implicit Generalized Predictive Self-Tuning Algorithm for Liquefied Natural Gas Storage Station
Authors: Deng Ya Ting , Long Wei , Sun Shao Jie
Published: July 2011

The advanced implicit generalized predictive self-tuning control algorithm was used against those characteristics of the outlet’s gas pressure such as large-time delay, time varying, vulnerable to random noise and so on. Through the simulation, a good tracking performance was shown, and in the process of actual operation, it also achieved satisfactory control effect.
Ansai County Land Resources and the Sustainable Use of Land
Authors: Hu Ming
Published: July 2011

By analyzing Ansai county utilization current situation and land utilization the past years change condition by the fact that 1989-2005 annual land inquires into a data's to locality , have revealed land utilization middle have problem. Ansai County land use patterns by state policy affects in more, at the same time for the oil industry also has a great influence on the land use type.
Simulation Studies on Model Reference Adaptive Controller for Permanent Magnet Synchronous Motor Drive
Authors: Qu Zhi Yong , Ye Zheng Mao
Published: July 2011

Permanent magnet synchronous motor systems are usually used in industry. This kind of systems is nonlinear in nature and generally difficult to control. The ordinary linear constant gain controller will cause overshoot or even loss of system stability. Application of adaptive controller to a permanent magnet synchronous motor system is investigated in this paper. The dynamic model of the system is given and the stability is also analyzed using Popov's criterion. The steady state error can be eliminated using adaptive controller combined with an integration term. Simulation results show the performance of adaptive controller with fast response and less overshoot.
Analysis of Constant-Stress Accelerated-Life-Test Data of Electric Appliances
Authors: Zhao Jing , Sun Li Hua , Liang Yong Chun , Yan Cai Hong , Wang Hui
Published: July 2011

In the field of electric appliances’ reliability, the constant-stress accelerated-life-test is commonly used to test the reliability of electric appliances. A new analysis method based on constructed data is introduced to analyze the constant-stress accelerated-life-test data of electric appliances under Weibull distribution. The correlation between shape parameter and characteristic life is took into account and the estimated value of characteristic life is modified, which increase the model fitting optimization and improve the analysis precision. Moreover, the method avoids table lookup and is easy to be realized by computer software in the application of reliability engineering for electric appliances.
Dynamic Power Management for Embedded Wireless Devices
Authors: Liu Fa Gui , Xing Xiao Yong , Wu Ze Xiang
Published: July 2011

The energy consumption of WLAN card makes up a significant proportion in the embedded system, which makes the effective power management on WLAN card play an important role on energy-saving and WLAN card longevity. This paper introduces a method of dynamic power management for WLAN card: manipulating the WLAN card driver to achieve the transition state of the WLAN card, acquiring WLAN card load which ultimately achieves the dynamic power management optimization algorithm. The experiment is presented to prove the feasibility of the implementation for the purpose of energy consumption saving on WLAN card.
Vibration Analysis of the Continuous Truss Girder Bridge by the Finite Truss Elements
Authors: Yang Shi Ruo
Published: July 2011

The train and the continuous truss girder bridge are coupled together as one composite system. Truss girder bridge is idealized as an assemblage of finite truss element. The equations of the train and truss girder bridges time varying system are set up by using the principle of total potential energy with stationary value in elastic system dynamics and the“set-in-right-position”rule for forming structural matrices. This method is more convenient than the finite elements. The vibration responses of the train and bridge are calculated when the the passenger trains pass through a continuous truss girder bridge at speeds of 90km/h and 120km/h The results show that the passenger train can pass it safely and comfortably
Elastic Strain Energy of a Nanowire in Three-Point Bending Test with the Consideration of Surface Effects
Authors: Zeng Xian Wei , Deng Jia Quan
Published: July 2011

Three-point bending tests of nanowires with Contact atomic force microscopy reveal that the Young’s modulus of a nanowire is size-dependent. The modulus changes with the diameter of a nanowire. This size dependency can be explained within the framework of classical continuum mechanics by including the effects of surface stress. In this study, an analytical solution has been derived for the elastic strain energy of a nanowire with both ends clamped and contacted by an AFM tip at its midpoint. Different from previous theoretical models, the present model can handle the case of large deflection, where the displacement of the nanowire is in the same order of the diameter. Based on the equivalence of elastic strain energy, the apparent Young’s modulus of a nanowire is expressed as a function of the elastic modulus of the bulk and that of the surface, and the dimensions of a nanowire.
Pluralistic Teaching Practice in Probability Theory and Mathematical Statistics
Authors: Wang Cui Xiang
Published: July 2011

Based on the author’teaching practice, this paper introduced some learning and experience from teaching in Probability Theory and Mathematical Statistics. The main content includes five aspect as follows：Integrate with historical backgrounds and inspire the passion of students,Apply ways of induction and analogy in order to deepen the comprehension of conceptions, Combine theory teaching and modeling teaching, Highlight the applied background of fundamental conceptions in class,Utilize computer aided instruction and visualize abstract content, etc.
Workflow Model Design Based on N-Tree for Process Management in PDM
Authors: He Fei , Liu Yuan Ning , Liu Jing , Chen Ying
Published: July 2011

In this paper, a workflow model based on N-tree for process management in PDM system is presented. It streamlines circuits in process management to sequence, branch, parallel, and loop patterns. It also offers this workflow model’s mechanisms of construction, executing, and state transition by definitions of workflow’s node properties, node constraints and state set. Last it exhibits an instance of applying this workflow model to process management of a simple PDM system.
A Microprocessor-Based Monitoring and Control System via Internet in Case Study of Pet Care
Authors: Lin Hsiung Cheng , Liu Liang Yih , Pai Kuo Hung
Published: July 2011

Since the past years, the microprocessor (8051) has been still playing an indispensable role as a controller in industry applications because of fast executing process, low-cost, small size and low power consumption, etc. It, however, usually lacks of long distance transmission, graphical interface and vision. On the other hand, VB is now a very popular software package for graphical interface design due to easy exploring and low price. Combining both superiorities as above, this paper develops a remote visional microprocessor-based monitoring and control platform using VB graphical interface. The nearby PC (server) can collect real-time sensing signals from the 8051 through RS232 and transmit it to remote PCs (client) for on line monitoring mechanism via Internet. Also, the client can send the control signals to the server and thus control the 8051. The real-time case study for feeding care in the Pet House is provided to verify its well performance and remote Web-based capability in term of fast, simple and robust performance.
Research of Pinyin Chinese Input Method Based on μC / OS-II Real-Time Operating System
Authors: Wang Kun Ling
Published: July 2011

The μC / OS-II is a complete, portable, curing and cutting of preemptive real-time multitasking kernel. The strong task management capabilities provides a good platform for the multi-tasking system. Based on the analysis of the Chinese pinyin coding, according to the characteristics of the μC / OS-II real-time operating system, achieved a semi-intelligent pinyin chinese input use the small keyboard.
Summary of Affinity Propagation
Authors: Zhou Yong , Xing Yan
Published: July 2011

Affinity Propagation(AP)is a new clustering algorithm, which is based on the similarity matrix between pairs of data points and messages are exchanged between data points until clustering result emerges. It is efficient and fast , and it can solve the clustering on large data sets. But the traditional Affinity Propagation has many limitations, this paper introduces the Affinity Propagation, and analyzes in depth the advantages and limitations of it, focuses on the improvements of the algorithm — improve the similarity matrix, adjust the preference and the damping-factor, combine with other algorithms. Finally, discusses the development of Affinity Propagation.
A Modified Particle Swarm Optimization Algorithm with Cases Studies
Authors: Kuo Cheng Chien , Chen Hung Cheng , Taso Teng Fa , Chiang Chin Ming
Published: July 2011

s paper presents a hybrid algorithm, the “particle swarm optimization with simulated annealing behavior (SA-PSO)” algorithm, which combines the advantages of good solution quality in simulated annealing and fast calculation in particle swarm optimization. As stochastic optimization algorithms are sensitive to its parameters, this paper introduces criteria in selecting parameters to improve solution quality. To prove the usability and effectiveness of the proposed algorithm, simulations are performed using 20 different mathematical optimized functions of different dimensions. The results made from different algorithms are then compared between the quality of the solution, the efficiency of searching for the solution and the convergence characteristics. According to the simulation results, SA-PSO obtained higher efficiency, better quality and faster convergence speed than other compared algorithms.
A Numerical Study on the Effect of Bond Length on the Bonding Performance of FRP-Concrete Interface
Authors: He Zhu Jie , Xu Tao , Tang Chun An
Published: July 2011

In this paper, the bond length effect of FRP plate on bonding performance and the distribution patterns of the stress in FRP plate was investigated using 3D Realistic Failure Process Analysis (RFPA3D) code to study the debonding mechanism of the FRP plate bonded to concrete block. Numerical simulations show that the progressive debonding of FRP plate bonded to concrete occurs in the concrete on the condition of different bond lengths can be divided into four stages: elastic-deformation stage, elastic-softening stage, elastic-softening-debonding stage and softening-debonding stage. It is also show that the interfacial bond strength and the global slip of FRP-to-concrete increase with the increase of the bond length.
Circumferential SH Wave in the Inhomogeneous Magneto-Electro-Elastic Cylindrical Curved Plates
Authors: Yu Jian Gong , Ding Jun Cai , Liu Jun Hong
Published: July 2011

Based on linear magneto-electro-elasticity, the circumferential SH wave equation of transversely isotropy piezoelectricity-piezomagnetic functionally graded cylindrical curved plate is obtained. The Legendre orthogonal polynomial series expansion approach is employed to derive its asymptotic solution. The dispersion curves, electric potential and magnetic potential distributions are calculated. The influence of the piezoelectricity and piezomagnetism on the circumferential SH wave is investigated and the influential factors are analyzed. Finally, the influence of the gradient field and the ratio of the radius to thickness on the piezoelectric effect and piezomagnetic effect are illustrated.
H1 -Galerkin Expanded Mixed Finite Element Methods for Pseudo-Hyperbolicequations
Authors: Li Mei Xia
Published: July 2011

H1-Galerkin mixed finite element method combining with expanded mixed element method are discussed for a class of second-order pseudo-hyperbolic equations. The methods possesses the advantage of mixed finite element while avoiding directly inverting the permeability tensor, which is important especially in a low permeability zone. Depended on the physical quantities of interest, the methods are discussed. The existence and uniqueness of numerical solutions of the scheme are derived and an optimal order error estimate for the methods is obtained.
Optimal Design of T-S Fuzzy Controller Based on Improved Genetic Algorithm
Authors: Dong Ling Jiao , Su Shao Xing
Published: July 2011

To solving the problem that there had been too many undetermined parameters in the fuzzy control rules, it presented a simplified Takagi-Sugno, namely T-S, fuzzy reasoning method. It reduced the parameters of the IF-THEN rules greatly. In addition this paper also improved the genetic algorithm on the analysis of the prior genetic algorithm, by which the global optimal parameters of the controller can be found easily and quickly thus the control rules can be amended and perfected. The simulation results show that the improved genetic algorithm can find the optimal parameters at a high speed and the optimized T-S fuzzy controller can obtain an excellent control performance.
Rheological Characterization of the Systems Clay-Polymer. Drilling Fluids Application
Authors: Gareche Mourad , Zeraibi Noureddine , Allal Ahmed
Published: July 2011

In this article, we demonstrate how the non ionic polymer, the polyethylene oxide (PEO) with molecular weight 6000 g/mol of varying concentration mass (0.7%, 1%, 2% et 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions (6%) in the water. The different rheological tests made in simple shear and in dynamic on the ternary system (water-bentonite-PEO), showed the influence of the polymer on the rheological properties of this drilling fluid. The PEO which presents an affinity for the bentonite particles slows down the kinetic of aggregation of the clay particles. Also the analysis by X-rays diffraction on different samples revealed the intercalation of the clay platelets on one hand and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand. The Herschel-Bulkley rheological model is used for the correlation and the interpretation of our experimental results.
The Microstructure and Mechanical Properties of Ni-Based Superalloy after Service Exposure in Gas Turbine
Authors: Yoo Keun Bong , Lee Han Sang , Kim Doo Soo
Published: July 2011

Many investigations about superalloys and coatings have been done in the laboratory, but evaluating the degradation condition of hot section components during service is still important not only for repair and reuse but also for outage prevention. Time dependent degradation for 1st stage blades of gas turbine was investigated. The degradation analysis for used blades was divided into microstructure changes by position in the blade and mechanical tests. In the microstructure analysis, the rafting and coarsening of γ', MC decomposition and TCP(Topologically closed packed) phase formation occurred and progressed with increasing service time, and especially at the leading and trailing edge of top layer which should be a check points for used blades. Stress-rupture test results of 25,000 and 52,000 EOH(Equivalent Operating Hours) for used blades were also compared with serviced time and position in each blade.
Optimum Design for Life Extension on the End Coupling of Aluminum Hot Rolling Process
Authors: Lee Young Shin , Lee Hyun Seung
Published: July 2011

The end coupling is the main component of the aluminum hot rolling process. The end coupling used for transmission of rotational power with heavy-duty load. Fracture of the end coupling causes serious economic injury because an end coupling is a very expensive component and takes a long time to repair. To prevent the destruction of the end coupling it is essential for mechanical life cycle to be known. In this paper, a parameter study on end coupling was performed in order to minimize maximum stress of an end coupling under static loads. To verify the interference of spindle assembly with modified end coupling, kinematic simulation was performed by applying the various combination type and dynamic boundary condition of the spindle assembly. The interference of an optimized model did not occur during combination process and driving process. As a result of an optimum design for life extension on end coupling, the maximum stress of end coupling was reduced about 26% compared with original model.
Ab Initio Phonon Dispersion Curves Used to Check Experimentally Determined Elastic Constants of the MAX Phase Ti3SiC2
Authors: Kirstein Oliver , Zhang Jian F. , Kisi Erich H. , Riley D.P.
Published: July 2011

The ternary carbide Ti3SiC2 is the archetype of MAX phases. To date, MAX phases have proven difficult to synthesize as sufficiently large single crystals from which single crystal elastic constants might be obtained. Therefore, the elastic properties not only of Ti3SiC2 but other MAX phases are extensively studied by ab initio methods. Recently single crystal elastic constants were experimentally determined for the first time using neutron diffraction. The experiment revealed extreme shear stiffness which is not only quite rare in hexagonal materials but also strongly contradicts the predictions of all published MAX phase elastic constants from ab initio calculations. In the present paper we would like to show that such shear stiffness can possibly be supported by ab initio calculations and the calculated phonon dispersion along high symmetry directions.
Phase Composition, Microstructure and Thermal Diffusivity of Cu/Si Composites Sintering Temperature Dependence
Authors: Cai Hui , Wang Ya Ping , Song Xiao Ping , Ding Bing Jun
Published: July 2011

Cu/Si composites may become novel high-performance electronic packaging materials owing to combining the advantages of copper and silicon components. Here, we prepared Cu/Si composites by being sintered below and above eutectic temperature 802 °C, respectively, and found that sintering temperature notably affects their composition, microstructure and thermal diffusivity. The composites sintered at 780 °C are composed of copper and silicon, exhibiting dispersed silicon particles and continuous copper matrix, but those sintered at 820 °C primarily contain Cu3Si compounds, and a porous microstructure is observed. The thermal diffusivity of the former is over 21 times higher than that of the latter.
Reliability Analysis for Inserts in Sandwich Composites
Authors: Banerjee Biswajit , Smith Brian G.
Published: July 2011

Inserts are used to transfer localized loads to structures made of sandwich composites. Stress concentrations near inserts are known to cause failures in sandwich panels. Experimental insert pull-out tests show that the load to failure can vary by 20% between batches of sandwich panels. Clearly, uncertainties in the mechanical properties of core and adhesive potting materials have to be accounted for in the optimal design of inserts in sandwich composites. In this paper, we use an one-dimensional computational model of an insert in a homogenized honeycomb sandwich panel to explore the utility of reliability methods in design. We show that the first-order reliability method (FORM) produces accurate estimates of loads that lead to low failure probabilities. We also observe that FORM is sensitive to the failure criteria and may not converge if the failure surface is not smooth and convex.
Experimental Study on Strengthening of Steel Structures with Fiber Reinforced Plastic
Authors: Dong Chen Song
Published: July 2011

An experimental study on the strengthening of steel structures with FRP (Fiber Reinforced Plastic) is presented in this paper. Test coupons were prepared by applying FRP patches on both sides of steel coupons. Standard tensile tests were conducted to the test coupons. Two types of CFRP (Carbon Fiber Reinforced Plastic) and one type of GFRP (Glass Fiber Reinforced Plastic) were studied. The load and strain data were recorded, and the stiffness and strength were derived. The results show that CFRP provides better strengthening than GFRP, but there is no significant difference between PAN graphite/epoxy and pitch graphite/epoxy laminates.
Strength and Fracture Behavior of Abaca Green Composites
Authors: Takagi Hitoshi
Published: July 2011

The present paper deals with the optimum processing condition of abaca fiber-reinforced green composites, followed by the examination of their strength and fracture behavior. Tensile properties of heat-treated abaca fibers were examined. It was found that the tensile strength of abaca fiber depended strongly on the heat-treatment conditions and that there was a critical condition which the strength of heat-treated abaca fiber was unchanged. After that, two types of abaca fiber-reinforced green composites were fabricated by a hot-pressing method, namely unidirectional and cross-ply composites. These green composites were made using woven abaca fiber as a reinforcement and dispersion-type, starch-based biodegradable resin as a matrix. The mechanical and fracture properties of the abaca green composites have been evaluated as a function of fiber content. These properties are comparable to those of glass fiber reinforced plastics. The tensile strength of abaca fiber reinforced green composites was affected by weft materials; namely the strength of green composites with soft cotton weft was higher than that of the composites with hard abaca weft. This phenomenon was derived from the damage in warp which was introduced during the hot-pressing.
Experimental Study on Theory of Critical Distance Applied to the Prediction of Fatigue from Notches
Authors: Clegg Richard E. , Duan Kai , McLeod Alan J.
Published: July 2011

Fatigue failure of metal components containing notches, cracks and other defects has been a very active research topic for well over seven decades because of its important practical and theoretical implications. Recently, Taylor and his colleagues have re-visited this topic and proposed the Theory of Critical Distance (TCD), which summarizes the early work by Neuber, Peterson and others in a unifying theory and predicts fatigue fracture with the use of a critical distance, L0. In this paper, an experimental and numerical study of the fatigue of notched and unnotched 6061 aluminium alloys is used to verify the TCD and some of the limitations of the TCD are discussed on this basis.
Low Cycle Fatigue Behavior of Ni-Base Superalloy IN738LC at Elevated Temperature
Authors: Kim Jae Hoon , Hwang Kwon Tae , Yoo Keun Bong , Lee Han Sang
Published: July 2011

High strength nickel-base super alloys have been used in turbine blades for many years because of their superior performance at high temperature. The prediction of fatigue life for superalloys is important for improving the efficiency. In this study, low cycle fatigue tests are performed the variables of total strain range, and room and elevated temperature. The relations between plastic and total strain energy densities and number of cycles to failure are examined in order to predict the low cycle fatigue life of IN738LC super alloy. The fatigue life is evaluated by the Coffin-Manson equation, also the predicted lives by plastic and total strain energy density are compared with experimental results.
Characteristics of Electron Beam Welded Ti & Ti Alloys
Authors: Mitchell Ryan , Short Andrew B. , Pasang Timotius , Littlefair Guy
Published: July 2011

Similar and dissimilar butt joint welds comprising combinations of commercially pure grade 4 titanium (CP-Ti), Ti-6Al-4V (Ti-64) and Ti-5Al-5V-5Mo-3Cr (Ti-5553) were created using the electron beam process. The resultant welds were studied by means of metallography, optical microscopy, mechanical testing and scanning electron microscopy. Mechanical testing was performed on welded samples to study the joint integrity and fracture characteristics. A scanning electron microscope investigation was performed on the fracture surface to reveal their fracture modes. While all weldments were crack free and most weldments exhibited mechanical properties comparable to the base metal, negligible ductility was exhibited during tensile testing joints of Ti-5553 welded to either Ti-64 or Ti-5553.
Light Emission from a Si Based ZnO Structure
Authors: Chen Fei , Zhan Xing Hua , Zou Chong Wen , Salcic Zoran , Gao Wei
Published: July 2011

A novel silicon-based light emitting structure comprising a lithium doped zinc oxide film and a high energy electrons generating silicon structure is presented. Red light emission with wavelength of ~630 nm is generated and recorded in electroluminescent spectrum under an applied DC voltage of 8.5 V.
3D SOI Elements for System-on-Chip Applications
Authors: Kogut I.T. , Druzhinin A.A. , Holota V.I.
Published: July 2011

Base technology of local 3D SOI-structures formation has been proposed. Using this technology the electrical characteristics were developed and simulated of following original device elements for the microsystem applications: standard and matrix SOI CMOS-transistors with 3D gates, switching elements on Schottky diodes, contact electrodes with 3D surface, elements for highly sensitive integral accelerometers with registration of a field emission current, hermetical microcavities and microchannels under the surface of a SOI-substrate, field emission silicon microcathodes.
Photovoltage Performance of Ge/Si Nanostructures Grown on Intermediate Ultrathin SiOX Layers
Authors: Podolian A.O. , Kuryliuk V.V. , Nadtochiy A.B. , Kondratenko S.V. , Korotchenkov O.A. , Kozyrev Yu.N. , Sklyar V.K. , Rubezhanska M.Yu. , Lysenko V.S.
Published: July 2011

An enhanced photovoltage is reported to occur in Ge/Si structures with a SiOx layer having a thickness of 0.5-2 nm and placed between a Si substrate and Ge nanoislands. The effect is interpreted in terms of an increased separation distance for photoexcited electrons and holes occurring in the stress fields generated in the oxidized Ge/SiOx/Si structure. The electron-hole separation is modeled utilizing finite-element method techniques, and a good agreement between the experimentally observed enhancement and the computationally increased inter-charge distance is obtained. It is also found that insertion of the oxide layer accelerates the photovoltage decay. This result is interpreted in terms of competing processes, involving the direct recombination of the separated electrons and holes and multi-trapping behavior typical of disordered systems caused by Ge islands.
The Nanometer Scaled Defects Induces with the Dislocation Motion in II-VI Insulated Semiconductors
Authors: Babentsov V.N. , Boyko V.A. , Kolomys A.F. , Shepelski G.A. , Strelchuk V.V. , Tarbaev N.I.
Published: July 2011

Dislocation-related defects induced by dislocation motion in p-CdTe were studied. Generation of “fresh” dislocations from the indented point of the CdTe (100), (110), and (111) surfaces at room temperatures was visualized by the chemical etching and low temperature photoluminescence in a mapping regime. The crystallographic orientation of the dislocation rosettes of macroscopic plastic deformation lines was analyzed on the (100), (110), and (111) surfaces.
Diamond – Graphite Heterostructures Formed by Nitrogen and Hydrogen Implantation and Annealing
Authors: Popov V.P. , Safronov L.N. , Naumova O.V. , Nikolaev D.V. , Palyvanov Yury Nikolaevich , Kupriyanov Igor Nikolaevish
Published: July 2011

Graphitic-diamond heterostructure may be very helpful not only for high frequency or power devices but also for new generation of electronic devices like single electron transistors or quantum computers operated at room temperature. The goal of our work was a formation of nanothin amorphous carbon or graphite layers with sp3 or sp2 hybridization inside the nitrogen doped synthetic monocristalline diamond by high dose hydrogen implantation. It was found that there is a “critical” dose of 50 keV hydrogen molecular ions equal to 4x1016 cm-2 above which an irreversible drop of the sheet resistivity in implanted layer occurs after annealing above 1000 oC. The nature of this conductivity was investigated and it was shown that variable range hopping mechanism of 3D conductivity dominates in investigated temperature interval. Four times higher value for the onset of this conductivity in comparison with “critical” dose for graphitization is explained by interaction of implantation induced defects with nitrogen atoms and surface defects.
ZnO Films and Crystals on Bulk Silicon and SOI Wafers: Formation, Properties and Applications
Authors: Chubenko Eugene , Klyshko Alexey , Bondarenko Vitaly , Balucani Marco , Belous Anatoly I. , Malyshev Victor
Published: July 2011

In present work the investigation of the electrochemical and chemical hydrothermal deposition processes of ZnO on silicon is presented. The influence of the electrochemical process parameters on the characteristics and morphology of the ZnO deposits is analyzed. Electrochemical deposition from non aqueous DMSO solutions on porous silicon buffer layer is also discussed. The details of the chemical hydrothermal deposition from the nitrate bath of high-quality ZnO crystals on silicon substrate are presented. It was shown that morphology and size of synthesized ZnO crystals depends on the temperature of the deposition bath. Differences between photoluminescence of electrochemically deposited ZnO thin films and hydrothermally synthesized crystals are shown. Electrochemically deposited ZnO films demonstrate defect-caused luminescence and hydrothermally grown ZnO crystals shows intensive exciton luminescence band in UV region. Hydrothermal deposition of high-quality ZnO crystals on the surface of electrochemically deposited ZnO seed layer with porous silicon buffer improves photoluminescence properties of the structure which is useful for optoelectronics applications. Possible applications of ZnO as gas sensors and photovoltaic devices are considered. Aspects of ZnO electrochemical deposition on bulk silicon and silicon-on-isolator wafers for integration purposes are discussed.
Semi-Analytical Models of Field-Effect Transistors with Low-Dimensional Channels
Authors: Kohmyakov A. , Vyurkov V.
Published: July 2011

A semi-analytical model which is applicable to description of ballistic field-effect transistors with low-dimensional channels is proposed. For instance, such transistors can be manufactured on a “silicon-on-insulator” wafer. The model accounts for single-gate and double-gate structures with one-dimensional and two-dimensional channels. It differently describes the regimes of a transistor above threshold and below threshold. The first implies an essential influence of charge inside the channel on a potential distribution; the second supposes a negligible charge inside the channel. Both approaches are mainly based upon an approximate solution of the Poisson equation.
Effects of High–Energy Neutrons on Advanced SOI MOSFETs
Authors: Kilchytska Valeriya , Alvarado Joaquin , Militaru Otilia , Berger Guy , Flandre Denis
Published: July 2011

This work discusses the degradations caused by high-energy neutrons in advanced MOSFETs and compares them with damages created by γ-rays reviewing the original researches performed in our laboratory during last years [1-6]. Fully–depleted (FD) Silicon-on-Insulator (SOI) MOSFETs and Multiple-Gate (MuG) FETs with different geometries (notably gate lengths down to 50 nm) have been considered. The impact of radiation on device behavior has been addressed through the variation of threshold voltage (VT), subthreshold slope (S), transconductance maximum (Gmmax) and drain-induced barrier lowering (DIBL). First, it is shown that degradations caused by high-energy neutrons in FD SOI and MuG MOSFETs are largely similar to that caused by γ-rays with similar doses [1,3]. Second, it is revealed that, contrarily to their generally-believed immunity to irradiation [7, 8], very short-channel MuGFETs with thin gate oxide can become extremely sensitive to the total dose effect [2,3]. The possible reason is proposed. Third, a comparative investigation of high-energy neutrons effects on strained and non-strained devices demonstrates a clear difference in their response to high-energy neutrons exposure [6]. Finally, based on simulations and modeling of partially –depleted (PD) SOI CMOS D Flip-Flop, we show how radiation-induced oxide charge and interface states build-up can affect well-known tolerance of SOI devices to transient effects [4,5].
Analysis of the Fe-Ti and Mg-Ti-Fe Alloys Prepared by High Energy Ball Milling and their Hydrogen Capacity
Authors: Suwarno Hadi
Published: July 2011

The synthesis and characterizations of Fe-Ti and Mg-Ti-Fe alloys with the atomic ratio of Fe:Ti = 2:1 and Mg:Ti:Fe = 2:5:6 prepared by mechanical alloying technique in toluene solution and measurement the hydrogen absorption properties of the yields have been performed. The Fe-Ti and Mg-Ti-Fe elemental powders are milled with the milling time of 30 h, in a Mixer Mill, type PW 700i high energy ball mill. The milled specimens are analyzed with an X-ray diffractometer, Philip, type PW 1710, using Cu as the anode tube and l = 1.5406 Å. Qualitative and quantitative analyses are determined usingRietveld methoddeveloped by Fuji Izumi. The microstructure of the specimens after milling and hydriding are identified with a scanning electron microscope, Philip type 550. The refinement analysis of the x-ray diffractions results for Fe-Ti alloy shows that before milling the specimen consists of Ti and Fe phases, and after 30 h of milling new phases identified as FeTi and Fe2Ti are formed. In case of Mg-Ti-Fe alloy after 30 h of milling new phases identified as Fe2Ti and FeTi compounds are formed with the absence of Mg-Ti and Mg-Fe. Quantitative analysis of the milled powders shows that the mass fractions of FeTi and Fe2Ti phases are correspondingly 22.5 wt% and is 21.1 wt%, and the rest is Fe. The disappearance of Mg peaks after milling is suggested from the transformation of the crystallite into amorphous state. On hydriding at room temperature, the milled Fe-Ti and Mg-Fe-Ti powders are transformed into b-Ti4FeH8.5, Fe and TiH2. Considering the high hydrogen capacity and the low hydriding temperature of the Mg-Ti-Fe alloy compared to those of Fe-Ti alloy, the Mg-Ti-Fe alloy could be promoted as a new hydrogen storage material.
Development and Characterization of Bovine Hydroxyapatite Porous Bone Graft for Biomedical Applications
Authors: Herliansyah Muhammad Kusumawan , Suyitno  , Dewo Punto , Bin Abdul Shukor Mohd Hamdi , Ide-Ektessabi A.
Published: July 2011

The porous Hydroxyapatite (HA) ceramics have found enormous use in biomedical applications including bone tissue regeneration, cell proliferation, and drug delivery. This paper investigates the preparation and characterization of bovine Hydroxyapatite (BHA) porous bone graft by mixing sucrose powder as porogens with bovine bone powder. After uniaxially pressing at 156 MPa and pressurelessly sintering in air atmosphere at 1200°C for 2 hours the bioceramic showed an interconnecting porosity. The XRD analysis indicated that bovine hydroxyapatite (BHA) porous bone graft resulted in this research is single phase HA and is believed to be pure HA as indicated by the peak of the diffraction patterns (JCPDS 9-432). The phase analysis also shows that BHA porous bone graft is highly crystalline with domain crystallites sizes are between ~46 to ~99 nm (~4.6 to ~9.9 Å). Several trace elements in human bone such as titanium (Ti), iron (Fe), nickel (Ni), copper (Cu) and Zinc (Zn) were also detected in BHA porous bone graft as indicated by SR-XRF. This object is promising for bone regeneration because the interconnecting porosity in carbonated apatite provides a good environment for bone attachment and ingrowths