bluuebunny/crossref_metadata_2025 huggingface dataset:
Unsteady Darcian Natural Convection within Porous Media of Square Enclosure at Various Rayleigh Numbers
Authors: Faghiri Ali Hooshyar , Aybar Hikmet Şeli , Khamooshi Mehrdad
Published: August 2013

Transient natural convection within a 2D square cavity filled with a porous medium is numerically investigated. The left wall is suddenly heated to a constant temperature Th, while the right wall is suddenly cooled to a constant temperature Tc. Both the horizontal walls are insulated. The Finite Volume numerical method is used to solve the dimensionless governing equations. The results are obtained for the initial transient state assuaging to the steady state, and for Rayleigh number values of 102–104. It is indicated that the average Nusselt number showing an undershoot during the transient period and that the time needed to reach the steady state is longer for low Rayleigh number and shorter for high Rayleigh number.
Vibrodiagnostics and its Application in Manufacturing Practice
Authors: Monkova Katarina , Monka Peter
Published: August 2013

The article deals with the problems that originated at the testing of electromotors after their assembling. The laser inspection station for several types of electromotors was built as the part of assembly line for mass production of electromotors. At the testing, relatively frequent failures of the station were observed. As the inspection method for problems definition was used the vibrodiagnostics. It showed that errors were caused by the deficient fixing of motors during the testing. On the bases of vibration analyses results it was realized the station frame strengthening and so the improvement of operating mode of station.
Exact Solutions of the Vibration Problem of Beam Structures
Authors: Chekanin Alexander V.
Published: August 2013

The article deals with the actual problem of improving the accuracy of determining the dynamic characteristics of beam structures. To solve such problems the displacement method is used. Defining matrices are calculated with the Godunovs scheme. Numerical solutions in this case can be obtained practically with any accuracy within accepted hypotheses of the mathematical model of the calculated object. This suggests that the resulting solutions are standard. The examples of determining the natural frequencies of vibrations of beam structures that demonstrate an extremely high accuracy of the proposed algorithm are given.
Technical Characteristics and Applicationconcept of RBCC Engine
Authors: Luo Chun Qin , Ren Xin , Ma Xue Song
Published: August 2013

The technologies of Rocket Based Combined Cycle (RBCC) engine have been investigated for several decades and many academic achievements have been acquired by researchers, but wide gap exists between the practical applications and dream. In order to hackle the basic technical problems and promote practical applications of RBCC engine, this paper which is refered to many study results made by all the world and this paper’s authors analyzes the technical characteristics of RBCC engine on structural type, working mode and performance. Aiming at future applications of RBCC engine, technical challenge is analyzed. This paper also presents and analyzes feasible application concept for high-speed near-space flight mission using RBCC engine.
Study on Mixture Ratio Control of Bipropellant Propulsion System on Satellite Based on Bypass Control System
Authors: Li Ze , Song Tao
Published: August 2013

Bipropellant propulsion system (MON-1MMH) provides motivation for orbit transfer, attitude control and station keeping, is mainly applied for GEO satellite. Most bipropellant propulsion systems of satellite do not have the ability to control mixture ratio of oxidizer and fuel. The primary function of bypass control system, as an important part of bipropellant propulsion system, is to control helium pressure in the propellant tanks in order to control mixture ratio. This paper researches adjustment of mixture ratio for bipropellant propulsion system. Mathematical model for key components in bypass control system of bipropellant propulsion system and a reasonable model for system simulation combining the practical work of system is established. Through the dynamic simulation of Bang-Bang control with on-off solenoid valve for the adjustment of mixture ratio, structure parameters, working parameters and precision of feedback are all be considered for influence of system performance. The main factors affecting system performance are found out. The researches provide theoretical foundation for engineering implementation.
Compressor Instability: Stall, Surge and their Control
Authors: Chattopadhyay N.C. , Zahidul Islam Eunus H.E.M. , Ikram Md. Imtiaz , Mahmud Roohany
Published: August 2013

Every compressor has a stall line. In the vicinity of the stall line, the flow field is inherently unsteady due to the interactions between adjacent rows of blades, formation of small stall cells, flow separation and the viscous effects including shock-boundary layer interactions. These factors may aggravate to a state of local breakdown of flow or a total breakdown of flow or with a disastrous flow reversal. This paper starts with an overview on the previous researches about compressor stall and surge. Subsequently, it describes the effects of these instabilities in overall engine performance and design with/ without any control. The main objectives of this paper are to review the phenomenon of instability and methodology to suppress the rotating stall and surge by enlarging the stable operating range of compressor with the application of various control systems. This paper surveys research developments in this field and also tries to find an improved solution to increase the engine performance by applying various surge control strategies. Finally, the paper focuses on some recommendations towards a better design of compressor especially for aircraft power plant.
Linear Servo Motor Operating Mechanism and Control Technique for High-Voltage Circuit Breaker
Authors: Li Liang , Wang Yuan Tao , Wu Ling Ling
Published: August 2013

The linear servo motor mechanism for high-voltage circuit breaker is presented and the control to new operating mechanism is analyzed according to the d-q axis mathematics model and the thrust characteristics of the permanent magnetic synchronous motor. The three closed-loop control schemes of location, speed and current for moving contact control is designed and executed on DSP. The high accuracy grating is chosen as the speed and location sensors by which the requirement for real-time and high accuracy in the system can be fulfilled. The control and regulation of the moving contact movement during opening and closing of the high-voltage circuit breaker are realized which make the movement curve the same as the ideal one. The opening and closing abilities and running reliability of circuit breaker are enhanced and the mechanical and electrical lifespan is improved.
Nonlinearity of Maglev Actuator and Adaptive Vibration Control Using Improved FxLMS Algorithm
Authors: Li Yan , He Lin , Shuai Chang Geng
Published: August 2013

Maglev actuator is excellent for active vibration isolation, with non-contact form, low stiffness and rapid response. However, the actuators nonlinearity has to be restrained by the control algorithm. In this paper, the nonlinearity of maglev actuator was studied through theoretical analysis and experiment. An improved multi-channel FxLMS(filtered-x least mean square) algorithm was proposed, which considers the nonlinearity-induced harmonic frequency as extra line-spectrum excitation to control. Experiments showed that the improved FxLMS algorithm could efficiently compensate the nonlinearity of the actuators, thus had better effect when used in active vibration isolation system with non-linear actuators, compared with the traditional FxLMS method.
Optimal Trajectory Planning for Parallel Robots Considering Time-Jerk
Authors: Rashidnejhad Sajad , Asfia Amir Hossein , Osgouie Kambiz Ghaemi , Meghdari Ali , Azizi Aydin
Published: August 2013

A method for optimization in trajectory planning of 3RUU robot manipulators is presented in this paper. At first, to get the optimal trajectory, position analyses has been done on the 3RUU robot, then an objective function which have two terms is minimized: first term relevant to the total execution time and another one relevant to the integral of the squared jerk (defined as the derivative of the acceleration toward time) along the trajectory and this Guarantees that the obtained trajectory is smooth. This technique let to calculate the kinematic constraints on the motion of the robot, defined as upper limits on the absolute values of velocity, acceleration and jerk. , the total execution time does not require to be set priori. The algorithm has been tested in simulation and in comparison with other important trajectory planning techniques it has been given good results.
Mechanical Properties and Fracture Toughness of Alkali Treated Oil Palm Fruit Bunch (OPFB) Fibre/Epoxy Composites
Authors: Kalam Anizah , Jumahat Aidah , Salleh Z. , Hyie Koay Mei
Published: August 2013

Mechanical properties of oil palm fruit bunch (OPFB) fibre composites have been quite extensively research by many researchers. However fracture toughness of this composite is still not fully understood. Hence this research used Sodium hydroxide (NaOH) at three different concentrations (1%, 3% and 5%) to treat the Oil palm fruit bunch (OPFB) fibre to investigate the effects of alkali treatment on the mechanical properties and facture toughness of OPFB fibre/epoxy composites. Tensile and fracture tests results indicate that the 3% NaOH concentration gave the best mechanical properties. An increase of 12% and 18% were observed for tensile and flexural moduli, meanwhile the increament of 9% was observed for tensile strength. However no increase on flexural strength was observed due to the OPFB treatment. Suggestion has been made to further study on the NaOH concentration in the range of 2% - 4%.
On the Scatter of the Fatigue Limit of a Die-Cast Magnesium Alloy
Authors: Sofian Mohd , Mutoh Yoshiharu , Otsuka Yuichi , Miyashita Yukio , McEvily Arthur J.
Published: August 2013

In the present study, scatter behavior of fatigue limit for the die-cast magnesium alloy AM60B was investigated. Twelve fatigue limits were determined based on S-N curves obtained according to the standard fatigue test methods (that is based on the 0-2 or 0-1-2 combinations). The scatter of fatigue limit for the die-cast material was large where the values of Weibull modulus and COV were 16 and 6.8, respectively. This value of COV was in agreement with that obtained by simulated staircase method. The scatter of fatigue limit in the die-cast magnesium alloy was comparable to those in the die-cast aluminum alloy. In the die-cast materials, the fatigue limit determined based on S-N curve should be taken into account to have 6-10% of scatter from the mean value.
Numerical Investigation of Water Droplet Impact on Solid Surface in Microgravity
Authors: Tao Jun Jun , Qin Jun , Han Xue , Zhang Yong Ming
Published: August 2013

A numerical study based on VOF model has been carried out to investigate the dynamics of water droplet impact on solid surface in microgravity in comparison with that in normal gravity to discuss the differences of the extinguishing mechanism of water mist in different gravity level. Water droplets with different initial diameters and impact velocities were considered. The simulated results show that the deformation process in microgravity lags behind that in normal gravity. And it was also found that Dmaxand spread velocities are smaller in microgravity as the potential energy decreases and the time taken for a liquid droplet to reach its maximum spread has no obvious regularity. Hence, the effect of cooling the fuel surface and diluting fuel vapour with water mist in microgravity may be not as good as that in normal gravity.The critical impact Weber number for water droplet breaking up in microgravity is lower than that in normal gravity as the reduction of the value of Bond number, which may result in diluting fuel vapour with water mist in microgravity being more effective than that in normal gravity in some case.
An Analysis of Packed Bed Liquid Desiccant System
Authors: Salarian Hesamoddin
Published: August 2013

In this paper a new type of open absorption the liquid desiccant, air conditioning system will be introduced. The dehumidifier and regenerator play the most important role in this system.For liquid-gas contact, packed towers with low pressure drop provide good heat and mass transfer characteristics for compact designs. Thus, this analysis considers the packed tower liquid desiccant systems. The experimental data have been obtained from a built prototype of liquid desiccant system in a packed bed unit with a surface area per unit volume ratio of 125m2/m3, the liquid desiccant, viz lithium chloride. The result showed that the mean mass transfer coefficient of the packing dehumidifier was 0.02kg/m2s. Also the absorber characteristic parameter, the packing size or number of transfer units (NTU), and air-to-desiccant solution mass flow rate ratio (ASMR) are crucial parameters. These parameters affect humidity and enthalpy effectiveness and will be introduced and defined in this paper.
Experiment Investigation on Fluid Storage Characteristic and Transportation Performance of Propellant Refillable Reservoir in Microgravity Environment
Authors: Zhuang Bao Tang , Li Yong , Pan Ha Lin , Hu Qi
Published: August 2013

Satellites store and manage propellant by surface tension. A surface tension propellant management device (PMD) consists of a propellant refillable reservoir (PRR) for propellant storage and propellant acquisition vanes (PAVs) for propellant transportation. PRR is a key part of vane type surface tension tank (STT), and its storage performance determines the fluid management of vane type STT. In the present paper, a model test system was established and microgravity drop tower tests conducted based on experimental study of fluid storage and transportation behavior of PRR. Laws of fluid storage and transportation of PRR in microgravity environment were obtained. The test results show that two types of PRR both have good liquid storage capacity, and the double cone PRR exhibits good liquid storage capacity in lateral acceleration. A rational design of PRR can effectively store liquid and control liquid transportation velocity. The test results offer a guideline for optimization of new-style vane type PMD, and also provide a new method for fluid control in space environment.
Thick Epitaxy Stepper Method for Special-Type Device
Authors: Tang Zhao Huan , Chen Jia , Tan Kai Zhou , Wang Bin
Published: August 2013

A stepper lithography method for thick epitaxy of special-type device was proposed. In this method, a mask with both alignment mark for proximity lithography and identification mark for stepper equipment was designed to solve the problem of precise alignment to patterns before thick-layer epitaxy and stepper lithography after thick-layer epitaxy. Using this method, the accuracy for alignment of patterns before and after thick-layer epitaxy reached 0.5 μm. This pattern alignment method special for thick-layer epitaxy is also applicable for stepper lithography of VDMOS with NBL, super-junction VDMOS, high-voltage complementary bipolar device and high-voltage BCD device.
The Study of CTOD Test and Allowable Value
Authors: Yu Qi Ming , Sa Hao Liang
Published: August 2013

In order to determine the heavy plate structure have sufficient fracture toughness, based on BS7448 fracture toughness test experiment standard,the study of the typical bridge steel material were extended to CTOD( crack tip open displacement) fracture toughness test at 20 °C, The average CTOD value of base metal which was more than the allowable value of CTOD were obtained,so the structure can satisfy the design need .
Atomistic Study on the Structural Stability and Site Preference of Rh7-xTxB3 (T = Fe, Cr and Mn)
Authors: Wang Xiao Xu , Qian Ping , An Zhi Wei , Zhang Zhen Feng , Shen Jiang , Chen Nan Xian
Published: August 2013

An atomistic simulation of the structural properties of the Rh7-xTxB3 series, where T is Fe, Cr, Mn, has been carried out using interatomic pair potentials based on the lattice inversion method. Calculated results show T atoms can stabilize Rh7-xTxB3 with Th7Fe3-type structure, and T atoms substitute for Rh with a strong preference for the 2b sites. The phase stability of the intermetallics Rh7-xTxB3 is tested by many means including random atom shift, global deformation and high temperature disturbance under the control of the pair potentials. Calculated unit-cell parameters for Rh7-xTxB3 agree with the experimental data very well. All the above results indicate that the potentials are valid for studying the structural properties of these kinds of complex structure of transition metal boride.
Aviation Accident Prediction Based on Auto-Regressive Integrating Moving Average Method
Authors: Gan Xu Sheng , Duanmu Jing Shun , Gao Jian Guo
Published: August 2013

In order to reinforce the efficiency and initiative of accident prevention for reducing accident loss, the surest way is to strengthen the prediction. In view of difficulties in aviation accident prediction, a prediction method based on Auto-Regressive Integrating Moving Average (ARIMA) is proposed. In this method, a trial model is first identified for an accident time series, and then the diagnosis is executed with the necessary adjustments. The calculation process including identification, estimation and diagnosis is repeated until obtain a satisfactory model. The example shows that, ARIMA has a good prediction for aviation accident and provides an important technique support for decision-making of aviation safety.
Anti-Oxidation Stability and its Mechanism of Waste Oil Biodiesel
Authors: Wu Jiang , Chen Bo Shui , Fang Jian Hua , Wang Jiu
Published: August 2013

The anti-oxidation stability of waste oil biodiesel (WME) was evaluated on an oxidation simulator set up by the author. The results showed that oxidative stability of WME was worse than that of petrodiesel by exhibiting higher acid values and peroxide values, as well as greater viscosity increases after oxidation. Furthermore, a conjecture was taken about the configurational changes and the oxidation mechanisms of unsaturated fatty acid methyl ester molecules in the oxidation process, according to the principles of free radical reactions and the results of both infrared and ultraviolet spectroscopic analysis. An idea was put forward that, during oxidation, cis-trans isomerization might occur in unsaturated fatty acid methyl ester molecules and conjugated double-bond might produce due to transfer of double-bond.
Real-Time Coplanar NURBS Curves Fitting in Motion Controller
Authors: Chen Chin Sheng , Chu Chih Wei , Lai Yen Shin
Published: August 2013

This paper proposes a real-time coplanar Non-Uniform Rational B-Spline (NURBS) curves fitting in CAD/CAM system to improve the fitting quality and reduce the calculation effort. The real-time NURBS curve fitting process consists of (1) the reading discrete points, (2) curve segmentation and data reshaping, (3) curve fitting, and (4) local and global modulation. According to the simulation and experimental results, the proposed approach certainly raises the fitting quality and the efficiency of calculation.
Investigation of Ion Energy Distributions with Two Positive Ions in a Dual-Frequency Sheath of Plasma Etching
Authors: Li Chun Guang , Huang Li Ping , Tian Ling , Zhang Ze Ming
Published: August 2013

A one-dimensional fluid and Monte Carlo model is developed to study plasma sheath in dual ratio frequency plasma etching. Electrons and two positive ions are considerated. The influence of low frequency, ions mass diversity on IEDs and temperature uniformity of wafer is discussed. The results show that the IEDs are greatly modulated by the low frequency and ion mass, and the maximum and minimum ions energy can be predicted by using damped potential. The two ions with different ion mass affect each other little in IEDs but the total ion flux. The lower ion flux has higher averaged ion energy and the higher ion flux has lower averaged ion energy when keeping the total power fixed. It results in a similar temperature uniformity of wafer.
Research on Ignition Characteristic of Short-Circuit Fault
Authors: Li Bin , Wu Ying
Published: August 2013

Under voltage of 220V, this article has carried out ignition test of three categories of combustible substance including polyurethane foam, cotton cloth and newspaper by simulation of short-circuit fault of aluminum conducting wire, so as to get the characteristic parameters of ignition of combustible substance due to short-circuit bead at different heights, summarize the distribution of fire origins for ignition of polyurethane foam due to short-circuit bead at different heights, and provide detailed fundamental data and effective technical support to fire disaster researchers of primary-level fire protection during onsite investigation.
Research on Overload Ignition Characteristic of Copper Wire
Authors: Wu Ying
Published: August 2013

In this test, PVC insulated wire is connected to self-made large current generator, so that different high-multiple overload currents (3Ie, 3.5Ie, 4Ie, 4.5Ie and 5Ie) passes through, with the increase of overload time, observe the change of insulation material of wire and ignition situations of different combustible substance (paper scrap, absorbent cotton and fire-retardant pipe). The results show that the higher the overload multiple, the larger the ignition capability of wire to combustible substance; even though it takes short time for fire-retardant pipe to smolder, but it takes longer time for fire-retardant pipe to become burned black and fail, and both cases are free from ignition, therefore, in case there is no collapse or burn-through, a certain degree of fire retardation is available in fire-retardant pipe in comparison with other two combustible substances.
Research on Internal Force Analysis of Shaking Table Test for Prestressed Pipe Piles Used in Tang Shan-Cao Feidian Expressway
Authors: Mu Huan Sheng , Gao Ling , Liang Yu Guo , Ma Wen Dong
Published: August 2013

In order to study the applicability of pipe piles in Tang-Cao expressway, shaking table model test was carried out. The results shows that, the internal force distribution of the pile under the action of seismic wave is basically the same with the behavior that is under the action of sine wave ; in the position of the 4 times pile diameter (distance the top of the pipe model about 200mm) appears the maximum axial force and bending moment; the change of the additional axial force in the upper portion of the pile is more complex, and tends to increase downward; the change of the moment tends to stable blow the distance of 20times the pile diameter from the pile top (distance the top of pipe model about 1000mm)
High Temperatures - Influence on the Material Properties of Cement Paste with Fly Ash
Authors: Padevět Pavel , Lovichová Romana
Published: August 2013

Paper describes properties of cement paste included addition of the fly ash. Firstly is described the preparation of the cement paste. Next part is focused on the testing of the properties. Results of the testing are summarized in properties like a compression strength, Modulus of elasticity and strength in bending. Finally the relation between material properties and volume weight is discussed. An article is described paste made from the same amount of cement and fly ash and water coefficient of 0.4.
Research on Strength of Steel Fiber Reinforced Concrete at Low Fiber Volume Fraction Based on Binary Variance Analysis
Authors: Yuan Jian Song , Gao Dan Ying , Yang Lin
Published: August 2013

Based on the strength tests, including compressive strength, split tensile strength, shear strength , of steel fiber reinforced concrete (SFRC) with different concrete strength grades (C20~C50) at low fiber volume fraction (0~0.7%), the influences of concrete strength grades and steel fiber volume on concrete strengths were studied, and the effect significance levels of the two factors was analyzed through the binary variance analysis. The results show that when the concrete strength grades are amongst C20 ~ C50 and steel fiber volume rates lie in the range 0~0.7%,the strengths of SFRC rises as concrete strength grade and steel fiber volume ratio increase ; the influence of concrete grade is more significant than that of steel fiber volume ratio on compressive strength and split tensile strength of SFRC; the influence of steel fiber volume fraction is less significant than that of concrete strength grades on shear strength of SFRC.
Numerical Simulation of Domestic Gas Deflagration Explosion and Verification of Computational Techniques
Authors: Kashevarova Galina , Pepelyaev Andrey
Published: August 2013

Accidents caused by domestic gas explosions occur regularly enough. Gas explosion accidents indoors are defined as deflagration explosions. The formation of an explosive cloud depends on many factors inside the building. To understand why the buildings in one case withstand an explosion but collapse in another case, more precise design models and methods of their realization are needed. We used numerical modeling to calculate the blast load intensity and find out the impact of the actual environment parameters. For the model verification we referred to the full-scale experiment on the deflagration of domestic gas in enclosed space.
Effects of Different Micro-Catchment Mulching Methods on Growth and Water Use Efficiency of Corn
Authors: Zheng Jia Ming , Sun Zhan Xiang , Feng Liang Shan , Zhang Yu Xin
Published: August 2013

The study on the effects of three unary and binary micro-catchment mulching methods including film mulching ridge and ditch plantation, film-mulching ridge and ditch film-mulching plantation and film-mulching ridge and ditch film-mulching straw plantation on growth of corn and different precipitation years was conducted in allusion to the low and unstable yield of corn in the western Liaoning province of China and in comparison with the traditional plantation model. Under the condition of this experiment, through film-mulching ridge and ditch film-mulching plantation and film-mulching ridge and ditch plantation, the time for seedling emergence of corn was shortened and the emergence rate of corn was increased. Through film-mulching ridge and ditch film-mulching straw plantation, the time for seedling emergence of corn was prolonged and the emergence rate of corn was increased in median water or dry years, but the emergence rate of corn was reduced in the high flow year. By contrast to traditional plantation model, film-mulching ridge and ditch film-mulching plantation and film-mulching ridge and ditch plantation boosted the increase in plant height and leaf area of corn and promoted dry matter accumulation in the early period of growth while the growth was slow, the plant height, leaf area and dry matter accumulation was always at he minimum value through film-mulching ridge and ditch straw mulching plantation in the early period of growth, but the growth rate was expedited in the late period during growth. Through film-mulching ridge and ditch straw mulching plantation, due to many reasons such as the growth process ahead of schedule and high temperature, the signs of precocity or premature senility come into being and leaf area and chlorophyll content decreases swiftly; through film-mulching ridge and ditch straw mulching plantation, the descent velocity of leaf area and chlorophyll content were reduced and the leaf senescence was postponed. In different precipitation years, the increases in water use efficiency of micro-catchment plantation were different, smaller in high flow year while larger in dry or median water year.
Vertical Motive Performance Test of the Rigid Hinge Expansion Joint of Jiashao Bridge
Authors: Zhao Yi , Peng Tian Bo
Published: August 2013

To adapt the serious temperature deformation, the rigid hinge expansion joint is used in the Jiashao Bridge. The vertical rotation test and shear deformation test are conducted to check the vertical motive performance of the expansion joint, and the test results show the rigid hinge expansion joint can meet the design requirements.
FEM Analysis of Bi-Prestressed Concrete Beam
Authors: Gao Feng , Liu Tong
Published: August 2013

Based on ANSYS software, the solid modeling method was performed to build the half model of bi-prestressed concrete beam. And the solution for solve the problem such as the constitutive equation, failure criteria , the method of modeling,the infliction method of prestressed was summarized in this paper. The heating-cooling method was used to achieve the bi-prestressed.The simulate method was reasonable while the built mode was performed to simulate the pre-arch and bearing capacity, simulate the pre-arch and bearing capacity of pre-pressed bi-prestressed concrete beam by FEM software ,and compared with the experiment results. And summarized the handling of the constitutive equation,failure criteria,the infliction method of prestressed, the method of modeling ,and so on. All of the method will provide reference for the research of Bi-prestressed concrete beam.
Steel and Steel-Concrete Composite Columns of HEA-Cross-Sections with Member Imperfections, Subjected to Buckling Compression
Authors: Karmazínová Marcela
Published: August 2013

The paper deals with the problems of the load-carrying capacity of steel and steel-concrete composite members composed of high-strength materials, subjected to compression. The attention is mainly paid to the buckling resistance in the connection with member imperfections, which are usually covered by the equivalent initial geometrical imperfection expressed as the maximal initial member curving in the mid-length of the buckled member subjected to compression. The paper is oriented to the analytical solution of the initial eccentricity based on the conception of the buckling strength and to the possibilities how to verify the initial imperfection experimentally. The analysis of this problem is shown on the examples of steel and steel-concrete composite columns represented by open HEA cross-section and by the same cross-sections partially encased by normal-strength and high-strength concrete. Using test results of the specimens subjected to compression the comparison of actual values of initial imperfections with the corresponding theoretical values is presented here.
Research on Preparing Recycling Boards by Using Non-Metallic Materials of Obsolete Printed Circuit Boards
Authors: Zhang Yan Chao , Liu Bo , Gao Wei Jing , Zhu Jia Hui , Duan Wu Biao , Yang Fei Hua , Guo Jian Ping
Published: August 2013

The printed circuit boards (PCBs) are the basis of all electrical and electronic equipment (EEE) and thus are one of the most important branches of WEEE stream. Present researches mainly concentrate on the processes of reusing noble metals and copper, and a great deal of nonmetals in PCBs are disposed by combustion or filling, which may cause secondary pollution and resource-wasting. So in this paper, we study how nonmetals are used to produce recycling boards through adding different adhesives, and obtain the best formulation and working conditions. The best formulation is that the binder is Polypropylene (less than 20%), additive are methenamine (little) and stearic acid (little). Effects of working conditions on the molding results are investigated. The results show that the optimum conditions for hydraulic pressure machine are the temperatures of 160 °C, warming and pressing time of 10 minutes and the press of 30MPa.
Parameter Optimization by Taguchi Method for Thermoplastic Polymer Using a Melt Spinning Machine
Authors: Wang Shu Wen , Su Te Li
Published: August 2013

Fused spinning method is the most commonly used method to manufacture man-made fiber and the most important physical property of as-spun fiber is tenacity, which is affected by process parameters including spinning nozzle temperature, cooling temperature, cooling wind speed and winding speed. First, we selected the appropriate orthogonal array for the experimental plan to conduct experiments. Coupled with signal-to-noise (SN) ratio and main effect analysis, we understood the impact of process parameters on quality and confirmed the reproducibility of the experiment, and furthermore obtained the optimal combination of process parameters.
Structure and Properties of CNT-PbO2 Anodes on Stainless Steel
Authors: Song Yue Hai , Ma Li Jie
Published: August 2013

An ideal anodes used for the electrochemical oxidation of organic wastewater should have excellent activity, stability and high oxygen evolution potential. In this paper the CNT (Carbon Nanotubes)-PbO2 films electrodeposited on stainless steel were prepared. X-ray diffraction (XRD) patterns and SEM images indicated that CNT particles and PbO2 were able to achieve co-deposit and the composite CNT-PbO2 films were compact. The cyclic voltammograms of the CNT-PbO2 films studied in 0.5M H2SO4 at a scan rate of 100 mV/s showed that the CNT-PbO2 film has high electrochemical stability. The results of wastewater treatment indicated that the CNT-PbO2 anodes have excellent activity in ammonia wastewater treatment.
A Simple Design-Oriented Model for FRP-Confined High-Strength Concrete
Authors: Lim Jian Chin , Ozbakkloglu Togay
Published: August 2013

This paper presents a study on the axial compressive behavior of fiber reinforced polymer (FRP)-confined high-strength concrete (HSC). A large experimental test database assembled from the published literature was used to investigate and quantify factors influencing the compressive behavior of FRP-confined HSC. The database consisted of 976 test data having unconfined concrete strength ranging from 6.2 to 169.7MPa. Based on the analysis results of the database, it was found that the threshold confinement stiffness increases significantly with an increase in concrete strength, which in turn adversely affects the strength enhancement of confined concrete. It was also observed that the hoop rupture strain of FRP shell decreases with an increase in concrete strength. Existing confinement models that are applicable to FRP-confined HSC were assessed using the database. Finally, a new simple design-oriented model for FRP-confined HSC developed on the basis of the database is presented.
Analysis of Mechanical Characteristic of Systematic Bolt in Loess Tunnel under the Drawing Load
Authors: Su Zhong Ming , Liu Rui
Published: August 2013

Based on the displacement solution of Mindlin problem, the elastic solution to the distribution of shear stress & axial force is deduced under the drawing load for mortar anchor in loess tunnel. The ultimate drawing load of systematic anchor in the sidewall is measured by means of field test based on a certain loess tunnel in Kelan-Linxian Expressway, and the forcing characteristic of the anchor is analyzed. The distribution forms of the shear stress & axial force are also discussed in different soil characteristics. The obtained results will offer the theoretical basis for the design &optimum of systematic bolt in loess tunnel, which has the guiding significance in the design and construction.
Study on Experiment of the Wire Rope Composite Anchoring
Authors: Cui Xi Guang , Tong Xu Yang , Dou Zhi
Published: August 2013

This article studied the wire rope net bottom connection system by an experiment which was researching on four class and seven different kinds materials. Then we get the experiment results by using different anchoring materials as anchoring end and studying the wire rope bottom connection system of tensile bearing capacity. Through the experiment and data analysis, we can draw conclusions that: Application in general situations, we can use M8 stereotypes retractor, but need to expand the curvature of the top ring, while using smooth design scheme to reduce stress concentration. Used in critical situations, we had better use special M14 bolt anchor, which has a higher bearing capacity and security. The presented methods in this paper are feasible and practical.
Numerical Simulation on Indoor Thermal Environment of Radiant Flooring Cooling System with Displacement Ventilation
Authors: Cai Wei , Lv Wen , Zhu Le Xian , Yang Peng Feng
Published: August 2013

The purpose of this study is to investigate the thermal environment of a radiant floor cooling system using the existing radiant floor heating system. The thermal environment of the model office space was analyzed using Computational Fluid Dynamics (CFD) method. Two typical air distributions (hybrid air cooling system composed of radiant floor cooling and displacement ventilation and all-air system) were simulated. Installing two human models in the office, the characteristics of heat transportation from the human model were also analyzed. The results show that two air distribution forms can meet the demand of thermal comfort. The operative temperature in the radiant floor cooling system was lower than in the all-air cooling system when each of the sensible cooling loads of the two types of HVAC system was the same.
A Lifting Device for the Maintenance of Great Mining Height Supports
Authors: Qiu Chun Yan , Zhang Yong , Yang Hong Fang , Huang Wei Min
Published: August 2013

In this paper a lifting device for quickly servicing top beam of the great mining height support on fully mechanized coal mining face is introduced and the technical characteristic,working theory,application effect in mine of the lifting device are expounded. This lifting device makes the safety and efficiency of supports maintenance improved greatly. The lifting device occupies small space and has simple structure and doesnt influence the motion and operation of supports. Labor-saving,time-saving ,safe and reliable are also one of the features.This lifting device can be used and the lifter winch be dismantled at any time and needs less maintenance personnel.The using of this device achieves the goal of senting maintenance personnel or accessories to the working height quickly,safely and accurately and accelerates the development of working face.
The Effects of the Manufacturing Errors of a Group of Sprags on the Engagement Properties of Sprag Clutch
Authors: Qing Mao Hui , Yan Hong Zhi , Tan Wu Zhong
Published: August 2013

Aiming at the problem that the overrunning clutch existing manufacturing error. Established the geometric model of overrunning clutch and the dynamic model using Adams, and then analyzed the engagement properties of the overrunning clutch with actual manufacturing error. Comparing with that of no manufacturing error, the angular velocity of outer race have large impact, the start-up sensitivity, stability of the clutch declined and the bearing capacity reduced because of the manufacturing errors of a group of sprags. The manufacturing errors of a group of the sprag makes the carrying capacity of the clutch is decreased. This paper provides some bases for manufacture of sprag clutch.
Study on Influence of Insulating Clapboard in the Process of Electrolytic Cleaning for Cold-Rolled Strip
Authors: Wu Jing Gao , Li Shuai Fang , Liu Xiao Kui
Published: August 2013

Two models with and without insulating clapboard were established. The electric potential distribution and the flow of electric current in electrolytic cell under the two models were simulated by Ansoft finite element software. The results show that the distribution of equipotential surface is the most intensive in the area close to the electric plate,and the current in the cell obviously skewed flows to the bottom of the strip under the insulating clapboard model , which is important to improve the current efficiency of the electrolytic cleaning. Finally, the influence of insulating clapboard on current efficiency and under different plate spacing were carried on by experiment and analysis, proved the correctness of the simulation results.
Non-Contacting Carbon Seal for High-Temperature and Large-Diameter Turbomachinery Applications
Authors: Zheng Xiao Qing , la Pointe Bill , Sciutto Steve
Published: August 2013

Non-contacting circumferential segmented hydrodynamic carbon seals have been used in aviation engines to seal lubrication oil from air flow path in bearing locations. Its tight clearance and long life from non-contacting operation are attractive to large gas turbine and steam turbine where efficiency is critical. In this paper, development of segmented carbon seals for large turbomachine is presented. The seal is targeting locations where temperature is over 500C (930F) and rotor diameter is over 0.38 meter (15 inches). Comparing to current circumferential segmented carbon seal technology, the new seal is capable of running 260C (480F) hotter and it is 3 times larger.Three sets of test seals were made with newly developed manufacture process. The test seals are 12 inches in diameter, made of three different carbon grades that were down-selected from a dozen candidates having potential of enduring high temperature of air and superheated steam. A test rig was set up to test one pair of seals at a time. One of the seals is facing high-temperature steam, while the other one is exposed to hot air.
The Preparation of Honeycomb Cordierite Mn-Ce/TiO2 Catalyst and Denitration Performance
Authors: Li Ruo Han , Zhou Song
Published: August 2013

SCR catalyst is the core of SCR technology. More attention to manganese oxide-based catalysts has been paid due to their excellent catalytic activities in low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR) in recent years. In this paper, the preparation method of honeycomb cordierite Mn-Ce/TiO2 catalyst and denitration performance is studied. Different amount of TiO2, Mn and Ce are supported on the cordierite ceramic and the SCR catalytic tests are conducted. In the tests, the influence of Mn/Ti molar ratio on the denitration performance and the effect of reaction temperature, inlet NO concentration, volumetric space velocity and ammonia nitrogen ratio on the denitration performance are found. The results show: (1) Mn/TiO2 catalyst has the highest catalytic activity when the Mn/Ti molar ratio is 0.4. (2) The optimum reaction condition of honeycomb cordierite Mn-Ce/TiO2 catalyst denitration reaction is the inlet NO concentration is 0.075%, volumetric space velocity is 4000 h 1 and ammonia nitrogen ratio is 1.05.
Research of the Halogen Phosphate Green Luminescent Materials Prepared by Sol-Gel Microwave-Assisted
Authors: Jiang Tao , Wu Ze , Guo Chao , Li Jian , Cui Yan Qun
Published: August 2013

In this paper, we used the sol-gel method to get the green luminescent material precursors and prepared the Sr5(PO4)3Cl: Tb3+, Tm3+ green luminescent material by microwave-assisted sintering. Then we have studied the effects of different microwave time and power changes to samples structure and morphology, the effects of different halogen changes to samples structure and morphology, and the effects of different doping concentration and Halogen changing to luminescent properties. Using the X-ray diffractometer we study the samples crystal structure and survey the morphology and size by the scanning electron microscopy. Through the luminescent spectroscopy study the effects of Halogen changing. The results shows that: the optimum reaction conditions are microwave-assisted sinter at 800W for 60 min. Using F, Cl , Br three halogen prepared a halogen phosphate luminescent material, optimal luminous intensity are chlorine phosphate.
Effection of Additive on Aluminum Nitride Nano-Wire Synthesis by Double Decomposition Method
Authors: Sun Yan Long , Dong Li Min , Jiang Tao , Guo Cao , Zhang Xiao Qi
Published: August 2013

An method for making AlN(aluminum nitride) nanowires by double decomposition, and the effection of additives was described. Future more, the growth mechanism of AlN nanowire synthesis with addictive were analyzed. AlN nanowire were synthesis by he AlCl3 and NaN3 in stainless steel cauldron without solvent and using Mg and Zn as additive. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study characters of the AlN nanowire. It is shown that the process can produce AlN nanowire with mean diameters ranging from 50 to 100 nm at 450°C. The additive has effective facilitated on the synthesis of aluminum nitride nanowires, can improve the properties of aluminum nitride nanowire, minish the average diameter of aluminum nitride nanowires.
The Design of a New Biaxial Decoupled Resonant Micro-Accelerometer
Authors: Yang Bo , Zhao Hui , Dai Bo
Published: August 2013

A new biaxial decoupled resonant micro-accelerometer is researched. The new biaxial resonant micro-accelerometer consists of four same tuning forking resonators, four pair of decoupled beams, four lever mechanisms and a proof mass. The decoupling between two orthogonal axes is realized by the decoupling beams, which will benefit to isolate two axes acceleration detection. The simulation is implemented to verify the basic principle by the Ansys. The simulation results prove that the effective frequencies of two acceleration sensitive modes are 3.699 kHz and 3.718 kHz separately. Two pair of resonator modes which are 23.893 kHz, 23.946 kHz, 26.974 kHz and 26.999 kHz separately have about 3kHz difference in frequency in order to prevent the mutual interference. And the interference modes are isolated with effective mode apparently. The input-output characteristic simulation results indicate the y-axis scale factor is 57.1Hz/g and the coupling output in the x-axis is 0.0148Hz/g, while the x-axis scale factor is 56.1Hz/g and the coupling output in the y-axis is 0.0073Hz/g, which proves that the new biaxial resonant micro-accelerometer is practicable and has an excellent decoupled performance.
Exergetic Cost Analysis of Marine Diesel Engine Waste Heat Recovery System Based on Matrix Model Thermo-Economics
Authors: Wang Zhi Yu , Zhou Song , Li Ruo Han , Li Cai Ling , Zhang He Fu
Published: August 2013

Diesel engine is the main power of the marine vessel, its thermal efficiency is the highest in all thermodynamic engines, but still more than 50% of the energy is not being used, so making full use of the waste heat of the main diesel engine scientifically and effectively, not only reduce the fuel consumption and the shipping cost, but also reduce the value of the ship EEDI effectively. To be able to design and transform the green ship, thermodynamic analyzing of the ship power plant and master the energy utilization of each part is necessary. Raising the efficiency of an energy system is within the domain of thermodynamics. Raising the efficiency cost-effectively (thermo-economics) is a multi-disciplinary problem in which thermodynamics interfaces other disciplines of knowledge which in this particular case are design, manufacture and economics. In this paper, it introduces the analysis method of thermo-economics briefly, the thermal economic analysis of the marine diesel engine waste heat recovery system is taken based on matrix model thermo-economics, and the unit exergetic cost is calculated. Some thermal equipments of the system are showed with the result of the performance evaluation. The results shows that thermo-economics is a promising tool for the analysis of complex energy systems. This method also provides a great prospect for energy system optimizations.
Experimental Investigation on Power Consumption in Reactor Coolant Pumps with the Function of the Flywheel
Authors: Gong Chun Ming , Yao Zheng Qiang , Hou Yao Zong , Xue Ya Bo , Cheng De
Published: August 2013

This article mainly discusses the dynamic characteristics of the experimental rotor system under the abrupt power shut circumstances, and to search the distribution of the power consumption during special working processes with an experimental method. On the basis of the experimental results, the simulation analysis is carried out on the Andritz RCP, and therefore, the dynamic characteristics of the real nuclear reactor coolant pump can be forecast, which just meets the need of the safety running in nuclear plant.