bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Age, Education and Seniority on Motivation of Employees
Authors: Hitka Miloš , Balážová Žaneta
Published: April 2015

Motivation can be changed significantly in dependence on meeting human needs, life situations, internal and external environment, etc. It is caused by different factors which affect motivation in different ways. These factors do not act separately but they are a part of mutually connected network of specific relations. In the paper we show the possibility of the impact of age, education and seniority on the motivation of employees. The level of employee motivation and employee performance can be influenced by means of their detailed knowledge.
Short-Term Momentum Effect: a Case of Middle East Stock Markets
Authors: Ejaz Abdullah , Polak Petr
Published: April 2015

The objective of this paper is to find short-term momentum effect in stock markets of the Middle East and to examine whether short-term momentum profits can be explained by risk-based CAPM model. Seven major stock markets from the Middle East were selected. Short-term momentum effect was found in all seven stock markets and CAPM does not adequately explain the short-term momentum profits but momentum portfolio returns are statistically significant. This paper is first attempt to bring major stock markets of the Middle East together and examine them for the short term momentum effect phenomenon. Future research should include more stock markets in order to have a better understanding of Middle Eastern stock markets.
Comparative Evaluation of National Intellectual Capital Measurement Models
Authors: Mačerinskienė Irena , Aleknavičiūtė Rasa
Published: April 2015

National intellectual capital is regarded as an important factor of a country’s ability to perform high value added functions including the ability to create innovations. Measuring national intellectual capital is still a complicated task. In this article national intellectual capital concept and measurement models are analysed in order to show how national intellectual capital could be measured. The findings show that there are several weaknesses of measurement models validity. Those weaknesses in more recent measurement models are minimized by introducing advanced national intellectual capital structural models and more complex value approximation methods. Analysis of selected national intellectual capital measurement models has shown that there are not many similar indicators used (from 21% to 60% of matching indicators), though results obtained by using these evaluation models have high significant correlation.
Alternative Investments: Valuation of Wine as a Means for Portfolio Diversification
Authors: Jurevičienė Daiva , Jakavonytė Agnė
Published: April 2015

This article analyses wine as an alternative investment tool and its relevance for investment portfolio diversification. Advantages and disadvantages of alternatives, benefits and weakness and peculiarities of investing in wine are systemised. In addition, the article looks at statistical data analysis of fine wine market and compares wine with other investment tools. The examination is based on three investment instruments: US equities (using SandP 500 index), bonds (using US 20-Year treasury constant maturity rate/DGS20) and wine (based on Fine Wine Investable index) using 1993–2012 (end of year) data. The investment portfolios made with two and three above-mentioned investment tools basing on H. Markowitz’s investment portfolio theory and effective curves are presented. It was found that return on investments only from equities and bonds or wine and one of these traditional instruments are signally less than from the investment mix of all three tools. Furthermore, portfolios made only from equities and bonds provide the lowest return compared to others. Choosing from two investments portfolios, results of bond/wine portfolios propose higher return with the same risk level compared to equities/wine portfolio. Consequently, despite some slowdown of wine index during financial crises, wine relevance for portfolio diversification in post crises period was proved.
High Cycle Fatigue Properties of Duplex Stainless Steel in Air and 3.5% NaCl Solution
Authors: Yu Shu Rong , Song Wei , Li Shu Xin , Kai Meng
Published: April 2015

The high cycle fatigue of super duplex stainless steel of SAF 2507 was investigated by rotating bending fatigue test in both air and 3.5% NaCl environment. The results showed that there is no much reduction of the fatigue life in corrosive environment, which is 90% of the air fatigue strength. In air fatigue, failure happens in ductile mode with austenite grains having finer and straighter fatigue striations than ferrite grains. Width and spacing of striations vary with the orientation and locations when the second cracking occurs. It is not reliable to identify the phase by morphology of striations. In 3.5% NaCl environment, the fracture exhibits a mixed mode of cleavage and quasi-cleavage in ferrites and ductile in austenite grains.
Effect of Repair Length on Residual Stresses in a Multi-Pass Butt-Welded 12Cr1MoV/P91 Dissimilar Pipe
Authors: Zhao Yan Ping , Gong Jian Ming , Wang Xiao Wei , Wang Yan Fei , Ge Zhi Qiang , Li Qing Nan
Published: April 2015

In this study, experimental and the finite element (FE) methods are utilized to investigate residual stresses of a multi-pass butt-welded 12Cr1MoV/P91 dissimilar pipe. X-ray technique is used to validate the FF results. Both methods show that residual stresses are significantly unsymmetrical distributed with respect to weld center line (WCL), and peak stresses exist on the inner surface of P91 part. The simulated results are especially in good greement with experimental ones within the weldment and its vicinity. Results for repair welds covering different circumferential angular are also presented to investigate the influence of repair length on residual stresses. It shows the shorter repair develops higher residual stresses, and this effect is more significant within the repairing area than the other regions.
Influence of Heat Treatments on the Microstructure and Mechanical Properties in Ti-10V-2Fe-3Al Alloy
Authors: Li Cong , Chen Jian , Li Wei , Qiu Wei , He Jian Jun
Published: April 2015

This paper reports the results of an ongoing research which was set up to investigate the effect of microstructures on the activity of different deformation mechanisms and the resulting mechanical behavior of the Ti-10V-2Fe-3Al alloy. Various microstructures were established by different heat treatments. Depending on the microstructures, obvious differences in the mechanical properties of this alloy were obtained. It is shown that in α+β phase field solution treatment conditions, with the increase of heating time, the fraction of globular α phase decreases, the compression strength increases. In β+(α+β) phase field solution treatment conditions, with the increase of heating time, alloys have opposite trends. In aging conditions, the microstructure and mechanical property do not change apparently with the aging time. The microstructure of the α phase and β phase has a great influence on the fractographic morphology.
Correlation between Magnetic Memory Signals and Mechanical Properties of 35CrMo Tempered and Quenched Steel
Authors: Guo Peng Ju , Chen Xue Dong , Guan Wei He , Zhao Hai Jiang
Published: April 2015

Magnetic memory signals and hardness of 35CrMo tempered and quenched steel were acquired during tensile testing. The magnetic signals of 35CrMo steel increased monotonously with the increase of tensile stress before yielding, followed by sudden decrease with further increase of stress after yielding. The zero-cross point ofHp(y) varied during tensile testing, indicating varied position of stress concentration zones with the process of tensile testing. Vickers hardness of the stress concentration zones of 35CrMo steel was lower than that around it, which may be attributed to the residual stress. The relationship between zero-cross point ofHp(y) and Vickers hardness was considered.
Residual Stress Analysis for Engine Block by the Grooving Method
Authors: Guo Chong , Lu Qing Hua , Zhang Pei Lei , Peng Bi Rong , He Xiao Feng
Published: April 2015

The study of residual stress in engine block has the potential to provide the necessary infrastructure for a wide range of scientific and technological developments concerning the automobile industry. Such study can act as centre of excellence for scientific studies in the field of materials science and machinery as well as for industrial applications. The basic principle of measuring residual stress with grooving method and the main measuring steps were introduced in this paper. Groove cutting in the internal surface of engine block surrounds a given area in which the remaining stress is released, and then the strain results are recorded through strain gauge. The residual stress test data were compared at different positions of each engine block. It is found that engine blocks A and D on the sides of engine develop higher residual stresses than blocks B and C in the centre of engine. The stresses can be higher than 200MPa in tension in engine block A, depending on the geometry, size, microstructure, subsequent welding process, and cutting sequence. In addition, residual stress at the bottom of engine is higher than that at the top because of the structure of the engine. The residual stress is also calculated by numerical modeling method from which it shown that the condition is commendably fit the results which the distribution of stress.
The Study on EMAT Applied in Nondestructive Testing of Elevated Temperature Material
Authors: Zheng Yang , Li Su Jun , Zheng Hui
Published: April 2015

Electromagnetic acoustic transducers (EMATs) has overcome many disadvantages of the traditional piezoelectric ultrasonic sensors and can be applied in elevated temperatures and on-line inspection. In an EMAT testing system, the tested material and EMAT itself make up a whole system. So the performance of EMAT is closely depended on some physical parameters of tested material. On the other hand, characteristic parameters of metallic materials are closely related to temperature, such as density, modulus of elasticity, electrical conductivity and magnetic permeability. As the temperature increases, the density of the metal material is reduced, the elastic modulus is reduced, the electrical conductivity is decreased, the magnetic permeability has a consistent increasing trend until the Curie point. Thus the EMAT detection performance affected by the change of temperature should be considered. This paper studied the effects of temperature on EMAT testing. Three materials of 20 # steel, Q235 and 16MnR were investigated. Testing temperature varies from 26 °C to 500 °C. The results show that under elevated temperature condition, EMAT echo signals still have a good waveform and stability. Meanwhile, signals are attenuated less than 2dB. It proved that the EMAT technique has a good steady performance in elevated temperature.
Structural Integrity Assessments by Measuring of Residual Stresses and Brittle Crack Toughness: A Thick Large-Scale Welding Study
Authors: Woo Wan Chuck
Published: April 2015

Residual stresses inherently occur in welds and through-thickness distributions in an extra thick weld is unclear to date, though it is important in various steel, plant, and shipbuilding industries. Here introduce a recent complementary technique to determine residual stress measurement methods. Spatial variations of residual stresses were determined through the thickness of 70-mm thick ferritic steel welds created using low heat-input (1.7 kJ/mm) one-pass electro-gas welding (EGW) and high heat-input (56 kJ/mm) multi-pass flux-cored arc welding (FCAW). The results show that significant tensile stresses (about 90% of yield strength) occur along the weld centerline near the top surface (within 10% of the depth) in the FCAW specimen. Meanwhile, in the EGW weld, the peak stress moved towards the heat-affected zone at a depth of about 40% of the thickness due to the high heat-input. Secondly, large-scale (1 x 1 m) brittle fracture experiments have been performed to examine the brittle crack-arrest toughness and crack propagation path in each case. The fracture behavior compares to the observations of the grain size, hardness, and Charpy impact energy of the localized crack region in each weld. This study provides an insight in terms of the relevance between residual stresses and the brittle fracture behavior.
Structural Integrity Role in Plant Life Extension - A Case Study
Authors: Shi Jin Hua
Published: April 2015

The steam generators at Advanced Gas-Cooled Reactor (AGR) nuclear power stations in the UK are potentially life-limiting components. Enhancing the capability to monitor the steam generators has been identified as having the potential to provide key evidence in justifying the extension of the generating lifetime of the stations.
It has been proposed to install new temperature measuring instrumentation to monitor reactor gas temperature and to provide additional data regarding steam generator operating conditions. The modification will be to introduce thermocouples to the bore of an intact steam generator tube to facilitate temperature measurement at or near to the locations of interest.
The modified steam generator tube will be sealed at the feed header upstand. Between the upper surface of the superheater header tubeplate and the wall of the superheater header, the thermocouple bundle and sheath will be contained within a rigid stainless steel guide tube. The guide tube will be attached at both ends by welds, each forming a pressure boundary. At the tubeplate a weld will separate the bore of the sealed guide tube from the steam space within the superheater header; a weld between the guide tube and the superheater header will separate the steam space within the superheater header from atmosphere outside the header.
In order to obtain a better design, three 3-dimentional finite element models have been created using ABAQUS. A series of cyclic pressure, and start-up and shutdown thermal transient stress analyses have been carried out to provide stress values for structural integrity assessments to be conducted using ASME III, Subsection NH and R5.
Failure Analysis and Redesign on Jacketed Polypropylene Reaction Kettle of Propylene
Authors: Yang Jing Qiang , Guan Kai Shu
Published: April 2015

Jacketed polypropylene reaction kettle is the key equipment of polypropylene reaction setting. Cracks and leakage occurred in the kettle wall near the lower thermometer pipe branch, which is a widespread phenomenon in this refinery. The results showed that the cracks were caused by low cycle fatigue. High edge stress concentration resulted from incorrect design of the jacket structure is responsible for the fatigue cracks. An improved measurement which is available and simple was introduced.
Nonuniform Flow Distribution Analysis of Air-Cooled Heat Exchanger
Authors: Lu Hong Liang , Xue Xiao Long , Tang Xiao Ying , Ding Jian Xun , Geng Xue Feng , Liu Xiao Min
Published: April 2015

The header and the multiple microchannel tubes connected to the header compose a complicated fluid network with several circuits, and the refrigerant flow into the header and is distributed to the microchannels in parallel by the refrigerant pressure driving in the inlet. So all changed details of geometry, operating conditions and thermophysical properties of the fluids lead to nonuniform refrigerant flow distribution in the microchannels. In the present work, one 6-pass 40-tube microchannel condenser as the research objective was equipped in a window type air conditioner prototype with the cooling capacity 5200W for Middle East T3 climate. A mathematical model based on fluid network theory was developed to predict flow distribution and phase separation in 9 flat tubes and their connecting headers on the second pass of the microchannel condenser. In the assumption of homogeneous flow, the mesh current analysis was employed to solve the mass flow of the loopi+1 by that of the loopi upon two phase pressure drop. The simulated mass flow rate distribution in 9 tubes is parabolic and approaches to uniform distribution when inlet quality comes to the median 0.45 from both directions.
Elastoplastic Analysis of Novel Parabola-Arc-Shaped Head for Internal Pressure Vessel
Authors: Wang Ning , Liu Hong Qi , Tu Shan Tung
Published: April 2015

In this paper, the elastoplastic stress analysis of a novel parabola-arc-shaped head subjected to internal pressure has been carried out using finite element method. Limit loads and burst pressures are obtained for various geometric parameters and compared with the conventional torispherical and ellipsoidal heads. For the same middle diameter and thickness, the novel parabola-arc-shaped head shows better mechanical performance than the torispherical head. The burst pressure is mainly determined by the size of cylinder and the burst always occurs in cylinder. The head can improve the burst load when the cylinder is relatively short. The improvement of the novel parabola-arc-shaped head is almost the same as the ellipsoidal head, while the torispherical head is slightly inferior. As the novel parabola-arc-shaped head can be more easily formed with less material consumed compared to the conventional ones, it should thus be applicable in engineering practice.
Fatigue Failure Analysis on Key Components of Bladder Accumulators
Authors: Niu Ya Ping , Chen Bing Bing
Published: April 2015

Fatigue failure analysis on key components of bladder accumulators was conducted. Failure fracture of the key components, which included the shell, the support ring and the oil inlet valve body in the accumulators, was investigated by optical microscope (OM) scanning electron microscope (SEM). According to the metallographic analysis and micro-hardness determination at the crack profile, crack initiation and propagation direction was confirmed. By simulation using the finite element method, it was detected that the peak stress of the key components applied on the contact surfaces. Obvious plastic deformation was observed at the region with high stress. However, the fatigue crack did not initiate at the contact surface, but occurred on the second high stress area without contact.
Rough Set Analysis of the Heat Conduction in the Steam Pipe
Authors: Zhong Wan Li , Wang Wei , Lin Jie Dong , Nie Ming , Liu Chang Hong
Published: April 2015

During the analysis of stability heat conduction in the composite pipes, firstly, when the heat equation contained fuzzy and random uncertain parameters, interval equations of the heat conduction are presented in the rough set. Secondly, the error expecting of heat conduction equation is presented. Finally, with upper (lower) approximation in rough set, a new method of the rough set analysis to deal with the stability heat conduction is presented.
On the Utilization of Shear Modified GTN Damage Model in Cold Rolling
Authors: Sun Quan , Zan Da Qian , Pan Hong Liang , Chen Jian Jun
Published: April 2015

Edge cracking is a commonly observed phenomenon in cold rolling process, but researchers appear to be far from fully understanding its failure mechanism due to the complex stress conditions of steel strip under the rolling condition. In this research, the shear modified GTN damage model coupled with Nahshon-Hutchinson shear damage mechanism was applied to investigate the damage and fracture behavior of steel strip in cold rolling. The results show that the shear modified GTN damage model is competent to predict the damage and fracture behavior of steel strip in cold rolling. By comparison to the cold rolling experiment, it presents that the prediction of edge crack occurrence of the shear modified GTN damage model is more accurate than that of the original GTN damage model.
Determination and Validation of Gurson-Tvergaard Model Parameters for Finite Element Simulation of Small Punch Test
Authors: Lu Yan Yan , Chen Liang , Guan Kai Shu
Published: April 2015

Small punch test (SPT) is a miniature sample test technique which can evaluate in-service material properties with an almost non-destructive method. Since the deformation behavior of the small punch specimen is complicated, finite element simulation embedded with Gurson-Tvergaard (GTN) model is adopted to simulate elastic-plastic behaviour until fracture. Choosing the proper GTN parameters is crucial for the small punch simulation, which directly influence the precision of load-displacement curve obtained from simulation. In this paper, load-displacement curve is divided into five stages and the parameters identification process is done by adjusting the simulation curve with experimental load-displacement curve in different stages which controlled by separately parameters. The results show that the parameters determined based on this criterion are not unique. In order to validate the reliability of this method, specimen’s minimum thickness of cross-section after fracture was introduced as an extra criterion which turned out to be feasible. Load-displacement curves cannot serve as the only criterion to verify the GTN parameters.
Fatigue-Fracture Solution of Iron Wire under Pseudo-Periodic Strain
Authors: Wang Jing Jing , Xiao Jian Hua
Published: April 2015

Under pseudo-periodic strain, the thermo-effect plays an important role in the fatigue fracture of material. How to construct the related mechanics model is a practical issue. For simple bending of iron wire under pseudo-periodic, based on local rotation concept, the deformation is described by the local rotation angle. Then, the related motion equations are used to obtain the theoretical form of life-strain rate relation. The results show that: (1) The local rotation angle rate can represent thermo-effects well; (2) The fatigue fracture is nucleated at the position of maximum local rotation angle; (3) The intrinsic mechanism of fatigue fracture of the material is the local rotation.
Critical Zone Approach for Structural Integrity of Power Engineering Components
Authors: Shlyannikov V.N.
Published: April 2015

This study is concerned with assessing the integrity of cracked steam turbine rotors components which operate under cyclic loading conditions. Damage accumulation and growth have occurred on the inner surface of slot fillet of key and in a disk and blade rivet attachment. Full-size stress-strain state analysis of turbine disk was performed for different stage of lifetime under considering loading conditions. As a result accumulated damage in critical zones of turbine disks depending on time of loading is defined. The tensile tests were performed for determination the main mechanical properties of disk’s material after loading history. The smooth and notched specimens were cut out from critical zones of turbine disk with given operating time. The low-cycle fatigue tests were performed with the harmonic test-cycle. Additional tests were performed on special designed program test-cycle, which equivalent to start-stop cycle of turbine disk. An engineering approach to the prediction of residual lifetime of turbine disks which is sensitive to the loading history at maintenance is proposed. Approximate estimations of carrying capacity are presented for the different stress-strain state of steam turbine disks at the operation.
The Effect of Elastic Modulus Rate in Stress Controlled Tests on the Modified Jeffrey’s Model for Structured Fluids
Authors: dos Santos Tainan Gabardo Miranda , de Deus Hilbeth Parente Azikri , Ribeiro Negrão Cezar Otaviano
Published: April 2015

Structured fluids are known to be dependable of their structural level. Examples of such fluids may be found in different industries as chemical, biomedical, manufacturing, food and oil. The mathematical models to describe structured fluids are normally composed by a coupled system: one constitutive equation (based on viscoelastic models) and one kinetics equation (an equation which describes the structural level evolution in time of the material). The works found in the literature use linear viscoelastic constitutive equations which do not account the dependence of the elastic modulus with the microstructural level in their fundamental hypothesis. In this sense, the present work aims to evaluate, through numerical simulation, the effect of a new constitutive equation in rheological tests and compare its results to those of the model developed by Souza Mendes and Thompson (2013), in which those considerations are not made.
Energy Release Rate of Delaminated Piezoelectric Shell Subjected to Electro-Thermo-Mechanical Loadings
Authors: Yang Jin Hua , Zhang Peng Jun , Qian Chang Zhao
Published: April 2015

The delamination growth may occur in delaminated piezoelectric shell subjected to external load and it will further cause structural failure. Based on the variational principle of moving boundary and considering the contact effect between delamination regions, in this paper, the nonlinear governing equations for the delaminated piezoelectric shell under electro-thermo-mechanical loadings are derived, and the corresponding boundary and matching conditions are given. At the same time, according to the Griffith criterion, the formulas of energy release rate along the delamination front are obtained and the delamination growth is studied. In the numerical calculation, the energy release rate and delamination growth of axisymmetrical piezoelectric cylindrical shell are analyzed, and the effects of voltage, temperature and humidity, mechanical load, delamination length and depth on delamination growth are discussed.
Research on the Damage Identification of Weld Metal Cracking of Metal Structure Based on PVDF
Authors: Li Xuan , Wang Ya Hui , Jiang Lei , Tang Fan Fang
Published: April 2015

A new detection method for measuring weld crack of crane’s metal structure is developed.It works by combining polyvinylidene fluoride (PVDF) with curvature operational shapes (COS) algorithm. First, the theory of damage identification using the imaginary part of frequency response function was analyzed, and the extraction approach of COS was illuminated in detail. Then, the fitting method which is called gapped-smoothing method (GSM) was chosen to obtain the COS of healthy structure.Next, experiments were carried out on a steel plate with weld cracks based on PVDF. The experiment result expresses that the positions of cracks could be located precisely and the index is very sensitive to the different length of cracks. Therefore it can provide reliable information for positioning and quantitative analysis of the weld cracks.
Verification of Linear Dependence of Plastic Zone Size on J-Integral for Mixed-Mode Loading
Authors: Žák Stanislav , Horníková Jana , Šandera Pavel , Pokluda Jaroslav
Published: April 2015

Determination of fatigue crack growth characteristics under shear-mode loading is a rather complicated problem. To increase an efficiency and precision of such testing, special specimens enabling simultaneous propagation of shear cracks under II, III and II+III loading modes started to be used rather recently. However, a description of crack growth rate in terms of appropriate fracture mechanics quantities demands a precise assessment of plastic zone size under various shear-mode loading levels. This contribution is focused on the numerical elasto-plastic analysis of stress-strain field at the crack tip in specimens made of a pure polycrystalline (ARMCO) iron loaded by mixed mode II+III. The dependence of plastic zone size on theJ-integral value described the wide region of loading. The results reveal that formixed mode II+III the small scale yielding conditions are fulfilled in the region where plastic zone size is smaller than 1/10 of the total crack length.
Factors Affecting Thickness of Prosthetic Socket in Thermoforming Fabrication
Authors: Tangpornprasert Pairat , Virulsri Chanyaphan
Published: April 2015

Nowadays, there are two socket fabrication methods in Thailand, which are resin casting and thermal vacuum method. The thermal vacuum forming method has more advantages than the resin casting method that ruins technicians' health from the volatile matter. Nevertheless, the thermal vacuum forming method can fabricate the socket with poor wall thickness distribution. The purpose of this paper is to study the effects of the feed rate of stump mould and the temperature distribution of the plastic sheet on the prosthetic socket wall thickness during the thermal vacuum forming process. The feed rates of stump mould were varied by using an industrial robot. The temperature distribution of the plastic sheet was controlled by circular and annular fiberglass insulators placed in its center. The results showed that the prosthetic socket wall thickness increases around the central area of the socket with a decreased feed rate of stump mould. The annular insulator increases the wall thickness slightly, while the circular insulator increases the thickness significantly. The wall thickness at the thinnest location increased from 1.6 mm up to 2.8 mm. In addition, wall thicknesses of areas beneath the circular insulator increased significantly between the marked positions-25 through +25.
Experimental Study on Critical Stress for Sediment Incipient Motionin Deep Channel of North Passage of Yangtze River Estuary
Authors: Pang Qi Xiu , Wen Chun Peng , Zhang Rui Bo
Published: April 2015

The average particle sizes of the sediment deposited in deep channel of North Passage of Yangtze River estuary are different at different channel segments in the flooding and dry seasons. As a response, the critical stress for sediment incipient motion might be different, which needs to be studied systematically especially after the channel reaches a new grade with depth of 12.5m. Therefore, a series of tests on the sediment were conducted to determine the critical parameters for the sediment incipient motion with different particle sizes between 0.01mm and 0.04mmcollected from deep channel of Yangtze River. The experimental data indicate that the critical shear stresses increase exponentially with density, and the stresses are 0.2-0.7Pa for the mud with density of 1200-1600kg/m3.And the relational expression between the critical shear stress and the depth was built, which might be applied in the mathematical model to simulate the process of incipient motion for sediment in deep channel of Yangtze River and others.
Local Consumption of PV Power Based on the Optimized Scheduling of Electric Vehicles Charging
Authors: Zhao Guo , Huang Xue Liang
Published: April 2015

According to the coordination and complementation of electric vehicles (EVs) and renewable resources, such as photovoltaic (PV) power generation, a micro gird system including EVs charging station and PV power generation was constructed firstly. Based on the target of maximizing the utilization ratio of PV power, considering the total cost of EVs charging, the time-of-use (TOU) price was introduced to establish the dual-objective optimization scheduling model of EVs charging. Furthermore, NSGA-II multi-objective optimization algorithm was applied to solve the model and the Pareto front of the non-dominated solutions was obtained. Finally, the optimized scheduling control strategy for EVs charging was proposed through normalized sorting of the non-dominated solutions. The optimal scheduling strategy could increase the utilization ratio of PV power on the basis of reducing the cost of EVs charging, promoting the local consumption of PV power.
The Influence of First Order Shear Deformation on Dynamic Buckling of Composite Bar
Authors: Wang Long Fei , Han Zhi Jun , Yan Xiao Peng , Lu Guo Yun
Published: April 2015

Taking stress wave propagation into account, the governing equations of composite bar with the clamped-fixed boundary conditions considering FSDT (first order shear deformation theory) are derived on the basis of Reddy’ theory and solved by the variable-separated method. The analytic expression of the critical buckling load is obtained basing on the characteristics of homogeneous linear equations having nonzero-solution. The results of the theoretical study and the numerical calculation indicate that FSDT has influence on dynamic buckling of composite bar, and the critical buckling load is small when FSDT is considered. They also show that the magnitude of effect taken by FSDT is small when the layer angle is big.
Study on Overpressure Protection System of Air Contaminations for Mobile Medical Shelters
Authors: Liu Ya Jun , Xu Xin Xi , Niu Fu , Tan Shu Lin
Published: April 2015

A design of overpressure protection system is presented for the mobile field medical shelters. The system compositions, structures and installations were comprehensively designed and manufactured by the modular analysis method according to the characteristics of defensive logistic operations for chemical, biological, radiological and nuclear air contaminations to the mobile field hospital. The effects of overpressure protection system were verified through a series of experiments on different shelters, which showed that more than 300 pascals overpressure could be achieved in the separate expanded shelters, and more than 100 pascals overpressure could be achieved in the interconnected expanded shelters. The experiments indicate that the overpressure protection system can meet the demands of relevant protection standards, and can provide effective protection for the medical shelters under suddenly CBRN contamination attacks.
FEM Analyses of the Radiation in Heating Forging Furnace
Authors: Tikal Filip , Duchek Michal , Nacházel Jan
Published: April 2015

The purpose of this study was to identify possible causes of longitudinal surface cracks found during early stages of ingot breakdown. However, these cracks need not necessarily form during forging or as a result of poor quality of the surface in metallurgical terms. Under certain conditions, they may occur even as the ingot is being heated in the furnace to the forging temperature. The cracks probably form within a few minutes after placing the ingot in the furnace as a result of the temperature gradient, which is most severe on the ingot surface. A numerical model was created to represent the case of three ingots in a furnace. Upon casting, the ingots are cooled down to no more than 600°C and then placed in a furnace at 1,100 - 1,200°C. Numerical simulations were used to analyse their internal stresses and temperatures.
Power Flattening on Design Study of Small Long-Life Boiling Water Reactor (BWR) with Tight Lattice Thorium Nitride Fuel
Authors: Trianti Nuri , Zaki Su'ud , Arif Idam , Permana Sidik , Riyana Eka Sapta
Published: April 2015

Preliminary study of thorium based fuel utilization with the addition of Pa-231 on tight lattice boiling water reactor (BWR) has been performed. In previous studies, the use of fuel composition Th-232 and U-233 as well as the use of protactinium as burnable poisons with hexagonal tight lattice fuel cell geometry has resulted the reactor life time of 30 years without refueling [1]. In this study, power flattening has been conducted on the reactor core by using radially heterogeneous fuel. Addition of the Pa-231 is expected to extend lifetime of the BWR core By optimizing the composition of the fuel elements (Th and Pa) at low moderation conditions (tight lattice) it can be obtained the reactor core which can be opeprated over 30 years without refueling or fuel shuffling. The Reactor core has a volume of 17,635.8 liter, power of 620 MWt, operating life of 30 and a maximum excess reactivity value of 0.384% dk/k, could be achieved by using a composition of U-233 enrichment of 8.1 to 11% and the addition of Pa-231 as much as 6.16 to 11.13% with a power density of 35.2 watts/cc.
A Framework of RFID-Based Complex Event Processing System for Assembly Manufacturing
Authors: Mao Na , Tan Jie
Published: April 2015

Owing to the dynamic and competitive business environment, manufacturing companies take real-time monitoring and rapid decision making based on RFID applications, which brings huge volume of information and events generated in the defined manufacturing workflows. Complex Event Processing (CEP) is introduced to solve the problems mentioned above. CEP is applied to handle diverse and large amount of low-level multiple data and primitive events for the purpose of identifying meaningful event patterns. It is very important to integrate the CEP technology to the manufacturing workflows. In this paper, we provide a novel framework of RFID-based complex event processing system for assembly manufacturing applications like cars and high-speed trains. It bridges the hardware in workshops and enterprise applications. The Complex Event Management System (CEMS), which is the kernel of the framework, can filter the irrelevant events and work with uncertain data. Furthermore, a concrete example is used to describe the framework and validate the feasibility in assembly monitoring of the car manufacturing.
Design and Evaluation of Stamping Module to Pattern Alignment Marks for LED Post-Processing
Authors: Sohn Young W. , Jeon Yong Ho , Seol Tae Ho , Lee Hye Jin , Lee Moon G.
Published: April 2015

LED (Light Emitting Device) is one of the most important and popular unit in display goods. Until now, the LED process could not make LED from broken substrates during production. This is because the damaged substrate cannot be post-processed by losing alignment mark on itself. After the substrate is pre-processed the substrate having LED dies are glued on blue tape. Therefore, if additional mark printed on the blue tape, it will be able to process the following post-process. In this paper, a precision stamping module to pattern the alignment mark on the blue tape is designed, fabricated and verified.
The Effect of Humping Semi-Enclosed Cage Structure on Polymer Chains Characteristics of TSI-POSS/PU Hybrid Composites
Authors: Pan Rui , Shanks Robert , Liu Yong
Published: April 2015

Trisilanolisobutyl polyhedral oligomeric silsesquioxane (TSI-POSS) with the humping semi-enclosed cage structure, was incorporated in concentrations of 7, 13 and 22 wt% into 4,4’-methylenebis (phenyl isocyanate) (MDI) and glycerol propoxylate to prepare TSI-POSS/PU hybrid composites, respectively. The polymer chain characteristics of these composites were investigated by wide angle X-ray scattering (WAXS) and molecular dynamics simulation approach. The results indicate that with TSI-POSS concentration increasing up to 22 wt% in hybrid composites, due to the humping semi-enclosed cage structure, distinct crystallite clusters are formed which lead to the micro-phase separation in composites. Meanwhile, the mobility of TSI-POSS cores and backbones in PU composites has been evaluated by the mean square displacement, which confirms that as the concentration of TSI-POSS increasing, the mobility of polymer chains are restricted apparently. Furthermore, it also indicates that the incorporation of TSI-POSS is as the rigid core in hybrid composites.
A Metadata-Based Simulation Resource Registration Method
Authors: Yu Jie , Cui Peng , Lin Jian Ning , Sun Li Yang
Published: April 2015

With the trend of network-centric simulation mode, more and more simulation models need to be shared and reused. On the basis of analyzing the characteristics of heterogeneous simulation resources, a specification was designed for the description of simulation resources in terms of functional attributes, application attributes and configuration attributes. A simulation resource registration tool was developed based on this specification.
Production Process Optimization of Mongolian Iron Ore Pellets for Baogang Group
Authors: Guo Zhuo Tuan , Guo Yong , Wu Di , Peng Jun , Wang Yong Bing , An Sheng Li
Published: April 2015

Baogang Group imported large quantities of Mongolian iron ore to solve the shortage of ironmaking raw materials. But the basic parameters of Mongolian iron ore in pellets production are deficient. In this paper, orthogonal experimental method was used in the optimization of roasting production process of Mongolian iron ore pellets. The results show that when the content of Mongolian iron ore is 55%, the factors affecting the expansion rate of pellets in order of decrease is bentonite proportion, roasting temperature, roasting time and preheating temperature. For pellets containing 55% Mongolian iron ore, the optimum roasting schemes are as follows: bentonite proportion at 3.3%, roasting temperature at 700°C, roasting time at 14 minutes and preheating temperature at 1280°C. Under this roasting scheme, the expansion rate of pellets is 13.41%, and the compression strength reaches 2275N, which meets the technological requires of large blast furnace. The main phase of the Mongolian iron ore pellets is hematite, with a porosity of 25%-30%. And the content of gangue and liquid phase is relatively low, which is beneficial to the reduction process of pellets in blast furnace.
Experimental Comparative Study of Carbon Nanotubes Synthesized from CO and CH4 by Flame Pyrolysis Method
Authors: Guo Yong Hong , Ding Kai Xiang , Jiang Peng , Sun Bao Min
Published: April 2015

In this paper, carbon nanotubes (CNTs) were synthesized by catalytic pyrolysis of CO and CH4 using flame pyrolysis method. The effects of using the two different carbon sources to the preparation of CNTs with all other conditions being equal were comparatively studied. The results showed that: the morphology of CNTs synthesized from different carbon source gases had certain difference. Higher yield of carbon nanotubes could be synthesized using CH4 as carbon source than using CO. At the same time, the former had less number of tube walls and the vascular bundles arranged more neatly. Synthetizing CNTs via catalytic decomposition of CH4 had more advantages than using CO by flame pyrolysis method.
Influence of the Brazing Methods on the Interface Structure and Property of the Cu/Al Brazed Joint
Authors: Yang Hao , Huang Ji Hua , Chen Shu Hai , Zhao Xing Ke , Wang Qi , Li De Hua
Published: April 2015

The Cu/Zn-14.1Al-0.9Si/Al joints were joined by flame brazing and furnace brazing, respectively. The influence of brazing methods on the interface structure and property of Cu/Al brazed joint was investigated. It was found that the interface structure near Cu substrate of the joint with different brazing method are both Cu/diffusion layer/Al4.2Cu3.2Zn0.7 layer, but the thickness of the interface layer of the joint with the flame brazing (3-4μm) is obviously thinner than that of the joint with the furnace brazing (5-10μm). The filler metal zone of the joint with flame can not find the Cu-Al IMCs. Instead, the block CuAl2 IMC can generate in the filler metal zone of the joint with the furnace brazing. For thinner interface layer, the joint with flame brazing has higher shear strength of average 60.5MPa, which is 20.6MPa higher than that of the joint with air cooling (39.9MPa).
Study on Titanium Alloy/Stainless Steel Welding Methods
Authors: Zhang Yu Feng , Huang Ji Hua , Chi Hai , Peng Li , Shen Yuan Xun , Pei Yin Yin , Yang Hao
Published: April 2015

In this paper, the research status and development trend of titanium alloy/stainless steel joining technology is reviewed. Characteristics and problems of titanium alloy/stainless steel jointing are analyzed. And then advantages and disadvantages of various jointing methods are compared.
Microstructure and Property of N5 Single Crystal Superalloy Joints Bonded by Transient Liquid Phase Diffusion Bonding
Authors: Chai Lu , Wang Li , Huang Ji Hua , Hou Jin Bao , Lang Bo , Yang Hao
Published: April 2015

N5 single crystal was transient liquid phase (TLP) diffusion bonded under different conditions in vacuum environment using Ni-base insert metal. Scanning electron microscopy (SEM) was used to observe the microstructure of the joints. Results show that the typical TLP joint could be divided into rapidly solidified zone (RSZ), isothermally solidified zone (ISZ) and diffusion zone (DZ). The widths of RSZ decreases with the increase of holding time at any established bonding temperature, amount of bulk compounds decrease at the same time. Bonding temperature has a complex influence on TLP joint. High temperature creep rupture tests were performed, results reveal that the sample fractured in the joint interface and the fracture mechanism has been studied.
The Vacancy Generation Influence on the Initial Stage of Ion Implantation
Authors: Parfenova E.S. , Knyazeva Anna G.
Published: April 2015

The coupled model is presented to describe the elements penetration into the surface layer of metal during the process of ion implantation. Mechanical stresses arising due to the interaction of particles with the surface affect the redistribution of the implanted impurity. In addition, the existence of vacancies in the metal surface and their generation under the stresses influence are taken into account. The kinetic law is written on the basis of the thermodynamics of irreversible processes. The solution had been found numerically. As a result, the distributions of impurity concentration and deformations have been obtained for various time moments. The comparison of the concentration profiles with vacancies and without their have been given.
Energy Balance and Heating of the Substrate at the Deposition of Coatings Using High-Power Pulsed Ion Beams
Authors: Simonova Anastasiya V. , Bleykher Galina A.
Published: April 2015

The energy balance on the substrate during the deposition of coatings using high-power pulsed ion beams of sub-microsecond duration is analyzed. A numerical model of thermal processes in the substrate is developed. With it, data on heating of a solid as a result of the deposition of the metal coating on its surface were obtained. It was revealed that even if the power density of the beam at the level of 109 W/cm2, the maximum temperature of the substrate does not exceed a few tens of degrees.
The Possibility of Boron Carbide Coating Formation by Using a Coaxial Magnetoplasma Accelerator
Authors: Sivkov Alexander , Rakhmatullin Ilyas , Makarova Anastasiya
Published: April 2015

A coaxial magnetoplasma accelerator can generate a dense and high velocity plasma jet by applying a pulsed high-current arc-discharge. The results of the experiment investigations of plasmadynamic synthesis in the B-C system have been shown while hyper speed jet boron carbide electric–discharged plasma steams onto copper substrate. The boron carbide coatings were formed on the copper substrate without a binder material. The formation of the crystalline boron carbide coating on the copper substrate was analysed through X-ray diffraction, transmission electron microscopy and scanning electron microscopy.
Biodiesel Production from Sunflower Oil
Authors: Amanbayev Daler , Ayinbora Joshua , Xin Low Ke
Published: April 2015

Southern Africa is composed of some of the poorest countries in the world. The energy demand in these countries compels them to spend millions of dollars in the purchases of mineral oil and gas to meet their demands while these countries have the ability to produce their own sources of energy from biodiesel. The most common way to produce biodiesel is via trans-esterification process which refers to a catalyzed chemical reaction involving vegetable oil and methanol to yield fatty acid methyl esters (biodiesel). Research has proven that the use of sunflower as a feedstock for biodiesel production yields zero waste. Apart from the fact that there is no waste generated, the sunflower is an attractor of bees and most sunflower farms have been used for honey cultivation, which will result in a two-way income generation, and hence will go a long way to reduce poverty and improve the GDP of Southern Africa countries.