bluuebunny/crossref_metadata_2025 huggingface dataset:
The Application of Multimedia Technology in Vocal Music Teaching
Authors: Fan Yue Bin
Published: May 2014

The application of multimedia technology provides great convenience for vocal music teaching, which becomes a hot spot of the researching and development of music teaching. Its characteristics are image, visualizations, highly informatization and network interactive. The use of this technology makes a change of the vocal music teaching from the traditional model to visual, audible, movable teaching mode, which enhance the student's perceptions of the abstract vocal music theory.
The Exploration of the Students' Social Practice and Innovation in Colleges for Electrical Engineering
Authors: Zhou Quan , Liu Chao
Published: May 2014

Social practice for Electrical Engineering’s student is one of the important means of quality education in Colleges and universities; what’s more, it is also an important part for students to known the society deeply and applies what they learn to it. However, the social practice system is not perfect at present stage. There are still some problems ,such as the lack of social practice bases,the short practice time ,and the single ways of practice .This paper analysis these problems which exist in the social practice activities of colleges, puts forward some improved methods and then makes a useful attempt to improve college students' social practice.
The Influence of Modern Information Technology on the Ideology of College Students
Authors: Lv Shan Guang
Published: May 2014

As the development of the advanced information technology, the modern technologies including the information and computer technologies are bring into the campuses. The modern information technology, such as the multimedia technology, the computer science as well as the network technology are taken as the available tools to present vivid samples to the students for education and entertainment, helping the college students to clearly and deeply understand the information, knowledge and enriching their life. Specialized to the ideology of the college students, this paper presented the influence of the modern information technology to the ideology of college students. The benefit and weakness of the introducing the modern information technology into the campuses is analyzed. Moreover, we proposed a series of method for properly utilizing the modern information technology, forming a novel pattern of the utilization of the modern information technology.
The Malfunction Analysis and Improvement of Hydraulic Test Bench for Undercarriage Retraction Actuator of a Helicopter
Authors: Yong Chen , Yu Jin Yong , Zhang Chun Ping , Gao Kun
Published: May 2014

The appeared malfunction when debug is analyzed,and the improved method is put forward. A hydraulic circuit is designed. The problem of great span and obtaining the high accuracy load force with high accuracy is solved successfully. It has the characteristic of high accuracy and stable performance [1].
Analysis of Current Situation about House Anti-Seismic Capacity of One Village in North China Earthquake Region
Authors: Yu Chuan
Published: May 2014

Due to poor economic conditions, houses in most rural areas of China are built by farmers themselves. While it still remains to be explored whether those houses could prevent themselves and people living in them from earthquake damages because they lack normative design and construction. With a village in North China whose seismic fortification intensity is 8 as the study subject, the paper explores practical anti-seismic capacity of current traditional folk houses by conducting a research about 315 households houses in this village and analyzing the house conditions and relevant seismic data. After study, the author comes to a conclusion that the traditional dwellings are with serious safety loopholes and can not resist earthquakes in this area, for those houses are influenced by earthquakes all year round and have more or less been damaged in varying degrees. Last but not the least, the paper presents some suggestions on earthquake resistant measures that newly-built houses in rural areas should adopt based on current practical situation.
Behavior Analysis of Looped Prestressed Tendons in Different Penetrating Strands Technology
Authors: Luo Jia Yi , Zhang Xie Dong , Guo Xing Mao
Published: May 2014

At present, small radius looped prestressed tendons have been widely used in cable-stayed bridge anchorages; the error limitation of stretch elongation in prestressed technology is 6 percentage, but in field it always exceeds the limitation. In this study, the main factors which lead to the stretch elongation were analyzed through a field full-size model test of a cable-stayed bridge. Moreover, the behaviors of ring prestressed tendons were studied for different penetrating strands technology and some advices and suggestions were finally made to offer an example for similar engineering.
Coarse Aggregate Replacement Ratio on the Properties of Recycled Concrete Bonding Effect
Authors: Cao Fu Bo , Li Feng Yun
Published: May 2014

Through a pull-out test was designed. The load-slip curves between recycled concrete with different recycled coarse aggregate replacement percentage and rebar were recorded. This article studied the impact of different recycled aggregate replacement rate and the anchorage length for the bond strength between the recycled aggregate concrete and reinforced, and provided a beneficial reference for engineering design of recycled concrete structure under similar conditions. Determined the recycled concrete and reinforced the bond-slip constitutive relation. Come to the bonding properties of reinforced recycled concrete with recycled aggregate rate increase gradually decreased in the anchorage length sufficient to meet the design requirements, performance depended on the pull-out strength of reinforced recycled concrete and reinforced the bond.
Development of Bridge Concealment Engineering State Detection Technology
Authors: Zheng Yi , Zhang Ke Chao , Chen Jian Zhang
Published: May 2014

Main detection and monitoring technology of bridges construction concealment engineering were carried out investigation and analysis. The use of concealed engineering inspection technology, monitoring technology were overviewed and analyzed. The development status of detection, monitoring technology at present reviewed and analyzed. Detection technology parameters on the internal prestress were compared. Technology development trend and foreground detection of concealed engineering were presented. Key words:bridge structure、concealed engineering、detection technology、monitoring technology、stress statement
Influence Analysis of Differences between Construction Temperature and Design Temperature on Structure
Authors: Xu Lei Ping
Published: May 2014

In order to study the influence of difference between construction temperature and design temperature on structure, an analysis program is compiled based on the beam element and plane shell element. Superposition calculation method is used to calculate the structural response cause by the differences between construction temperature and design temperature in every intermediary stage till the final stage. At last, construction stage analysis is performed on a stiffness skeleton arch with the program, which shows that the influence of difference between construction temperature and design temperature on structure cant be ignored and worthy of further study.
Demulsification of Emulsion Liquid Membrane Extracting Rare Earth Ions in Leaching Liquid of Phosphate Rock
Authors: Xie Zi Nan , Chen Qian Lin
Published: May 2014

This paper researched demulsification way for emulsion liquid membrane system extracting rare earth ions in leaching liquid of phosphate rock . Physical demulsification methods included heating, centrifugal, microwave. Chemical demulsification methods such as adding acid, alkal and inorganic salt were employed. The results showed that for Emulsion System A, the best way for demulsification was ultrasonic 30 min, 80 KHz sound intensity, 70°C ultrasonic temperature. The demulsification rate could reach 46% and concentration multiple of rare earth ions was 2 times. For Emulsion System B, centrifugal 90 min by 16000 r/min, the demulsification rate could reach the highest which was 52%, the concentration multiple of rare earth ions was 8 times.
The Analysis on Failure Characteristic of Piled Wharf System
Authors: Zhang Shi Ping , Cui Chun Yi
Published: May 2014

In order to effectively ascertain the failure mechanism of piled wharf affected by slope deformation in earthquake, numerical analysis is conducted by Finite Element Method in this paper. In the computational model, elastic plastic characteristic of subsoil, discontinuous behavior of pile soil interface, and nonlinearity of structure material are considered to conduct seismic computation in time domain. Numerical results show the possible locations of wharf structure which generate cracks and plastic hinges. Some conclusions are drawn and can be reference for engineering design and practical project.
The Design and Implementation of Intelligent Prediction System of Shield Construction
Authors: Shi Yi Ping
Published: May 2014

The paper discusses the factor and mechanism of the surface deformation caused by shield construction and introduces the process of design and implementation of intelligent prediction system of the surface deformation using BP neural network. It researches the system prediction precision and shows that it is a feasible method to predict the surface deformation.
The Numerical Analysis of Gradient Material Replacement on Arch Dam of Stress Concentration Area
Authors: Zhu Jian Bing , Su Zhi Min , Jiang Cheng Jie , Tian Zhi Fang , Lu Xue
Published: May 2014

During operation, due to change of outside temperature, edge of abutment and central part of concrete arch dam is prone to stress concentration, Concrete of tensile stress concentration area appears too large tensile stress easily, which results cracks to affect dam safety. This paper, by changing the material properties, that obtained high strength low elastic modulus of concrete, replaced arch rings with gradient material replacement method, to improve the stress state of dam and enhance strength for dam safety. By comparing the temperature rise with drop of the arch stress distribution area, the relationship of changing elastic modulus and stress has got. Using the VT technology acquire critical values of mutation elastic modulus.
Calculation Model for Thermal Crown of Work Roll in Hot Strip Rolling
Authors: Liu Zi Ying , Sun Yan Guang , Song Xiang Rong
Published: May 2014

The finite difference method model of temperature field and thermal crown of work roll on hot strip mill was researched. The temperature field and thermal crown were calculated, surface temperature distribution and thermal deformation were both reduced from center to edge. The computed and measured roll surface temperature were comparatively in good agreement with each other, practical application results show that the model has high calculating speed, high precision and can meet the needs of the strip shape on-line process control.
Pressure and Flow Stability for Ultra-High Pressure Water Jet System
Authors: Zeng Yong Long , Chen Kui Sheng , Zheng Fei Long , Xi Qiang Hua , Yu Cong
Published: May 2014

The paper introduces system components and working principle of the ultrahigh pressure water jet, with theoretical analysis on fluctuation characteristics of pressure booster pump flow. On the basis of the AMEsim simulation model established on various hydraulic components in the system, through a large number of simulation experiments to compare simulation curve with different parameters. Analysing the system characteristics for pressure and flow affected by some parameters such as: volume, booster pump motion control and the number of nozzles, in order to improve the system stability for pressure and flow and optimize the parameters.
The Comparison and Analysis of the System Utilizing the General Boiler Flue Gas Waste Heat
Authors: Liu Yan Feng , Wang Peng Cheng , Zhang Shao Shan
Published: May 2014

Flue gas recycling system is an effective way of saving energy and improving efficiency for coal-fired power plant. In this paper, the general low-temperature economizer, heat pipe type low temperature economizer, composite phase change heat recovery system are introduced. Combined with a 600MW unit parameters, the economies of various waste heat recovery system are compared.
Effects of Shenqihuafen Tablets on Immune Function in Normal Mices
Authors: Miao Ming San , Cui Ti Sheng , Cheng Bo Lin
Published: May 2014

Objective: observed the influence on the immune function of normal mices to study the Shenqihuafen tablets function characteristics of the lung tonifition and the spleen invigoration. Methods:administered different doses of Shenqihuafen tablets to normal mices ,determinated of the Percentage and index of macrophage cell in abdominal cavity. Results: compared with the blank group, large, medium dose Shenqihuafen tablets group showed significantly higher percentage of macrophage cell in abdominal cavity of mices (P < 0.01), large, medium and small dose of Shenqihuafen tablets group showed significantly higher index of macrophage cell in abdominal cavity of mices. High doses of Shenqihuafen tablets group promoted significantly the formation of hemolysin in mices (P < 0.01), large dose of Shenqihuafen group promote significantly hemolytic plaque formation in mices (P < 0.01). Conclusion: Shenqihuafen tablets increased significantly the immune of mices.
Concentration on Limonitic Iron Ore by Multi-Grade Magnetic Roasting-Low Intensity Magnetic Separation
Authors: Zhang Han Quan
Published: May 2014

Magnetizing roasting followed by magnetic separation is a compound technique for the beneficiation optimization of Huangmei refractory limonite. The natural limonite samples are obtained from Huangmei, Hubei province. The samples are characterized by TG-DTG-DSC. The content of major components is analyzed by SEM-XRAY, which is found that the sample iron mainly occurs in the form of limonite, with impurities including quartz, kaolinite, and barite. The feasibility of oxidized iron ore magnetic roasting limonite by multi-grade dynamic state magnetizing roasting is investigated. The effects of operation parameters such as roasting atmosphere, temperature and roasting duration are analyzed. The results show that: in the condition of the volume fraction of CO is 2% to 5%, the temperature is 700-780°C, and the roasting duration is 20 to 30 minutes. By multi-grade dynamic state magnetizing roasting, the grade of roasting limonite is nearly 33%, and the feasibility of separation is effective. A good index is created through simple mineral processing, the iron grade of concentrate reaches to 60% and the iron recovery rate reaches to 83.94%. It reveals that the multi-grade dynamic state magnetizing roasting device has a remarkable effect on roasting limonite.
Melt Pool and Single Track Formation in Selective Laser Sintering/Selective Laser Melting
Authors: Alkahari Mohd Rizal , Furumoto Tatsuaki , Ueda Takashi , Hosokawa Akira
Published: May 2014

Selective Laser Sintering/Selective Laser Melting (SLS/SLM) is one of Additive Manufacturing (AM) processes that utilize layer by layer powder deposition technique and successive laser beam irradiation based on Computer Aided Design (CAD) data. During laser irradiation on metal powders, melt pool was formed, which then solidified to consolidated structure. Therefore, melt pool is an important behavior that affects the final quality of track formation. The study investigates the melt pool behavior through visualization of the consolidation process during the single track formation on the first layer. In order to understand the transformation process of metal powder to consolidated structure and mechanism involved, high speed camera was used to monitor the process. Yb:fiber laser beam was irradiated on metal powder at maximum power of 150W. The laser processing parameters such as laser power, scan speed and layer thickness were varied in order to investigate their influence on the consolidation process. The result shows the size of melt pool increased with laser power and decreasing with increment in scan speed. Furthermore, with the increase of layer thickness, melt pool formation was unstable with chaotic movement. Significant amount of molten powder splattering was recorded from the melt pool. At high layer thickness also, the molten powder formed spherical shaped and the solidified molten powder failed to wet with the substrate.
Research on the Process of Liquid Droplet Impinging on the Liquid Film
Authors: Wang Z.H. , Meng X.
Published: May 2014

The impacting of liquid droplet on the liquid film appears in many engineering processes. In the fusion reactor, liquid metal is used as the heat transfer media, moderator and breeder in the condition of high heat flux. The paper analyzes the flow behavior of liquid droplet impinging on the liquid film from the aspects of experiment research. In the impinging, splashing means the production of secondary drop coming from the cusp of the crown flow or Worthington jet. Impinging velocity, liquid film thickness, droplet diameter, fluid properties and impinging angle have been analyzed separately.
Experimental Investigations for Compression-Flexure Characters of Laminated Box Beam Columns
Authors: Wu Ya Ping , Zhao Yu Ru , Zhang Jia Wei , Wang Yin Hui
Published: May 2014

In the action of bending load and axial compression, the deflection of the beam presents character of compression-flexure. For the thin-walled carbon fiber laminated box beam column, the beam deflections not only relate with load but also with the ply angle of layer, span width ratio. By using the experimental method, this paper this paper focuses on the experimental investigations of the compression-flexure characters of the laminated box beam column, in which the features of beam deflection variation with the span width ratio, ply angle, the axial compression ratio are given.
The Effect of Yield Strength in Isolation Layer on Dynamic Characteristics of Floor Partial Discontinuous Isolation Building
Authors: Zhang Peng
Published: May 2014

In the design of base isolated structure, the design of seismic isolation layer parameters is very important. Aiming at this problem, this paper using reinforced concrete frame structure of a partial discontinuity floor as an example, using ANSYS software, analyzed the dynamic characteristics of the based isolated structure, focused on the relationship between the yield stress of the isolation layer and the isolation effect, to provide reference for reasonable selection of seismic isolation layer parameters.
Photochromic Inhibition of Dyed Veneer Covered with Modified Transparent Film
Authors: Liu Yi , Xing Fang Ru , Hu Ji Hang , Guo Hong Wu
Published: May 2014

The overlying free film method was used to study the nanoTiO2 and UV absorbing agent modified water-borne acrylic varnish and polyurethane varnish of dyed veneer photochromic suppression effectiveness, using infrared spectrum analyzed the photochromic behavior of dyed veneer under different coated condition. Results showed that dyed veneer covered with UV modification film has the best light restraint, film modified by nanoTiO2 takes second place, and unmodified film worst. Photochromic inhibitory rate of UV modified polyurethane and acrylic paint film were 56.37% and 33.59% respectively, the rate of nanoTiO2 was 15.85% and 17.24%.
Design of Elevator Controller Based on FPGA
Authors: Zhang Shuang , Zhang Ying Sui
Published: May 2014

With the technology market and talent market demand for EDA continues to improve, the market demand for products and technology requirements of the market also will be reflected to the field of teaching and scientific research in the field. EDA technology improves, promoted the development of elevator controller. Elevator industry with the development of science and technology, constantly appeared in various places, people's life so, design of elevator controller is a practical example, also has the very big help to master the applications of EDA technology. The elevator controller is composed of two parts of hardware and software. This design using the EDA technology to carry out the operation, design is a 3 storey elevator controller.
The Structure Design and Numerical Simulation Research on Downhole Hydrocyclone Desander
Authors: Yan Yue Juan , Shang Yan Xu , Wang Zun Ce , Tian Mi , Wang Yue
Published: May 2014

A new downhole hydrocyclone desander with spiral deflector and cyclone cone was designed to apply in downhole solid-liquid separation according to the downhole operating conditions, such as a high produced liquid viscosity, narrow radial working space and closed bottom flow, etc. The structure parameters were designed primarily based on the effect of structure size on pressure drop, production capacity and separation efficiency. Numerical simulation was conducted on the base of Mixture model and Reynolds stress (RSM) turbulent model by Fluent CFD software. The geometrical model of single inlet and single outlet was established. The simulation calculations were carried out to analysis the effect of structure parameters change on separation efficiency and pressure drop, obtained the influence rules. The optimum structural parameters were confirmed. The numerical simulation results lay the foundation for the next experimental study.
Design and Prototyping of a Fuel Cell Controlling Equipment for Small Hybrid Driving Airship System
Authors: Kobayashi Toshiro , Fukushima Masahiro , Kanematsu Hideyuki , Utsumi Yuichi , Shimamoto Yoshiaki
Published: May 2014

In the present study, an airship for the fixed point observation of nara withering in village forests was designed and trial manufactured. The airship consists of a helium gas filling envelope of 4.5m in total length, propeller-driven motors, a polymer electrolyte fuel cell (PEFC) in order to achieve longer flight, Ni-H batteries, a CCD camera observation system, and propeller control systems. Automatic charging device was designed to charge the Ni-H battery from the PEFC in the sky automatically. It controlls the power system by using a micro computer in a mannar where the electromagnetic valve supplying hydrogen is open to recover the output voltage of the PEFC when the voltage of Ni-H battery decreased to a certain level, resulting in energy charging to the Ni-H battery and keeping the rotation of the moter. The opened electromagnetic valve is closed when the Ni-H battery full charged. Furthermore, after a certain hours operation when the output voltahge of the PEFC drops due to accumulation of impurities in hydrogen gas, the outlet valve will be opened to exhaust hydrogen containing accumulated impurities. It has been verified that as soon as the Ni-H battery voltage doropped to less than 3.8 [, the hydrogen inlet valve opened then the output of the power source increased suddnly to around 7 [.
The Response of a Broadband Light Source for an Optical Fiber Sensor Based on Surface Plasmon Resonance Technology
Authors: Wang Shinn Fwu , Hsu Cheng Lung , Kao Fu Hsi , Liu An Li
Published: May 2014

In this paper, the study on response of a broadband light source for an optical fiber sensor (OFS) based on surface plasmon resonance (SPR) technology is presented. The OFS is made of a multimode optical fiber which cladding was removed and coated with two layers of metal films. As a broadband light source is launched into the OFS at a suitable incident angle, we can obtain the intensity at the output of the optical fiber sensor. With the structure, the refractive index detection can be made by the SPR spectra that are obtained by an Optical Spectrum Analyzer (OSA). The OFS could be valuable for chemical, biological and biochemical sensing, etc. It has some advantages, such as, high resolution and stability, small size and real-time measurement.
The Electrostatic Potential inside the Electron-Optical Systen with Periodic Boundary-Value Conditions
Authors: Pei Ting Hang , Tsai Kuen Yu , Li Jia Han
Published: May 2014

A program based on the SOR method have been setup for calculating the electrostatic potential inside the electron optical system (EOS). This method can deal with large domain calculation more efficiently than by using the finite difference or finite element methods. Since the MEBDW system is composed of an array of EOSs, periodic boundary conditions in thexandydirections are applied. A case of EOS is demonstrated in this paper.
Corrosion Resistance of RE-AZ91 Magnesium Alloys
Authors: Yang Jun Jie , Li Yao , Xue Ping
Published: May 2014

Rare Earth (RE) were added to industrial AZ91 magnesium alloy, so that RE-AZ91 Mg alloy was produced by the process of die casting, so as to study the effect of RE on corrosion resistance and tensile strength of Mg alloy. The experiment results show that RE addition could improve the tensile strength and corrosion resistance of magnesium alloy at a certain amount of RE. RE-AZ91 had a good heat resistance, corrosion resistance at a high temperature or in the environment applied constant voltage, with a high tensile strength.
Simulation of Manufacturing Production Line Based on Arena
Authors: Zahraee Seyed Mojib , Golroudbary Saeed Rahimpour , Hashemi Ahmad , Afshar Jafar , Haghighi Mohammadreza
Published: May 2014

One of the controversial issues in manufacturing systems is bottleneck. Managers and engineers are trying to find methods to eliminate the bottlenecks and waiting times in the production line. More over the manufacturing companies are striving to sustain their competiveness by decreasing the bottlenecks, total cost and increasing the productivity. The objective of this study is applying the computer simulation to analysis the production line bottlenecks. To achieve this goal a color manufacturing line was selected as a case study and the basic application of arena 13.9 software. Finally the some modifications in the simulation model are proposed to improve the production line as well as to decrease the bottleneck.
Statistical Analysis of the Degradation Data Based on Pseudo-Life Distribution
Authors: Wang Jun Sheng , He Yi Zhou , Wang Yi Dong , Liu Wei Hua
Published: May 2014

Focus on solving the life and reliability problems of long-life and high reliability products, a method of modeling and parameter estimation on reliability evaluation and life prediction with accelerated degradation data was proposed in this paper. In the first, three statistical methods of degradation test were analyzed, then according to the features of accelerated degradation data, the statistical model of degradation data based on pseudo-life was established. This method can effectively utilize the horizontal information of degradation data of product under different accelerated stress level, and integrate the advantage that continuous-time function model fits the degradation curve of product strongly, and improve the accuracy of reliability assessment and life prediction of product.
Based on Lean Construction Standardization Management Analysis of the Performance Evaluation Index System
Authors: Wang Jing , Ma Rong Quan
Published: May 2014

The lack of performance evaluation for standardization management is a difficult problem for the sustainable development of construction industry. Based on this, this article on the basis of lean construction theory, starting from the standardized management of the key problems of lean construction, proposed a new lean construction of standardization management in the process of performance evaluation index system, to give "quality, cost, time limit for a project" trinity, the standardization of management performance evaluation system to support the decision-making to provide key information to lay the foundation.
Research on the Safety Transportation of Palm Oil by Chemical Tanker
Authors: Zhang Qiang , Jiang Na , Liu Xin
Published: May 2014

On the foundation of fully understand the nature of different palm oil, combining with some practical problems of bulk shipment of palm oil, a series of discussions and advices were provided in the process of cargo operationthe cargo loading and discharging, safe washing operation and cargo management during voyage. The present thesis aims to provide references for safety shipment of palm oil according to personal experiences on board.
The Instances of Highway Engineering Bidding Price Control
Authors: Zhang Su Juan
Published: May 2014

Highway engineering tender price control is the maximum limit of the construction cost. A reasonable bidding price control is the key factor in controlling the project investment effectively and preventing the bidders bidding up the price, it is also the key to a successful bidding. In this paper, the compilation process of bidding price control is given with practical examples of highway engineering.
Contaminant Lock Life Prediction of Double Flapper-Nozzle Servo Valve
Authors: Wang Xiao Hong , Yan Yu Jie , Li Qiu Xi
Published: May 2014

The thesis first analyzes the failure mechanism of contaminant lock, then the contaminant sensitivity theory or the Omega theory, which is first put forward by the Oklahoma state university hydrodynamic research center, is introduced and being applied to the servo valve contaminant lock life analysis and the contaminant sensitivity test method of servo valve is presented. After that, the value of servo valve contaminant lock sensitivity as well as the contaminant lock life can be calculated. It turned out that this method can accurately evaluate servo valves resistance on pollution lock and contaminant lock life, which can offer guidance on servo valve selecting and reliability analysis.
Views about Material Application Trends in Product Design
Authors: Liu Yuan
Published: May 2014

With the booming development of science and technology and the continuous progress of economy, the strategic focus of sustainable development is turning to ecological economy. The theory of people-oriented design becomes the mainstream, and green design, which is environmentally friendly and energy-saving, has become a trend in product design that attracting much attention. This article discusses at the height of humanization design that green material is necessary in future material application of product design, with the starting point of ecodevelopment; Under the theory of people-oriented design, smart material turns into the supporting material in future material selection of high-tech product; advanced composite is the leading trend in material application of future product design. This article will elaborate the future direction and the main trend of material research from the above three aspects.
Interactive Force of Two-Dimensional Compressive Deformation by Discrete Element Method (DEM)
Authors: Promkotra Sarunya , Kangsadan Tawiwan
Published: May 2014

Discrete Element Method (DEM) computer simulation is used to examine the influence of contact force between two-dimensional aggregates of polystyrene microsphere formed on the air-liquid interface. Colloidal aggregates have been treated as the granular material or discontinuum materials. The interaction force models are related to experiment which had done by digital video microscopy. The interaction mechanisms of the contact forces between particles in the colloidal system can be considered as a combination of spring and dashpot force and van der Waals force. According to the DEM, the interaction forces are evaluated to introduce relations between particles and the result comparison between the computer simulation and the experimental work. This study indicates that the behavior of the colloidal aggregates depends on the long-ranged (spring and dashpot) and the short-ranged interaction force (van der Waals). Besides, the behaviors shown in both computer simulation and the experiment are in good agreement. Thus, this computer simulation method can mimic the behavior of colloidal aggregates forming as a monolayer at the air-liquid interface.
Improving the Diffusion Controlled Cementation of Copper Ions on a Fixed Bed of Zinc Raschig Rings Using Flow Pulses in a Batch Reactor
Authors: El-Shazly Ahmed H. , Mubarak Ashraf A. , Bamufleh Hesham S.
Published: May 2014

This work investigates the possibility of improving the kinetics of the diffusion controlled cementation of copper on a fixed bed of zinc Raschig rings in a batch reactor by using flow pulses induced through the bed by a pulsating perforated disc. The kinetics of the cementation reaction was investigated under different conditions of initial concentration of copper ions, frequency and amplitude of oscillation (vibration velocity), zinc ring diameter, bed height and temperature. The effect of temperature was found to fit the Arrhenius equation with an activation energy of 5.5 kcal/mole which confirms the diffusion controlled nature of the reaction. A dimensionless correlation in the form that: Sh = 6.9 Re0.55Sc0.33(Pd/Bh)0.49was deduced. Industrial application of the results obtained was discussed.
Effect of Hydrogen on the Mechanical Behavior of API X70 Ageing
Authors: Ruiz M.A. Doñu , Perrusquia N. López , Herrera J.A. Ortega , Calderón G. Urriolagoitia , Suárez V.J. Cortés , Gonzales S. Rodríguez
Published: May 2014

The present work reports on the effect of hydrogen on the mechanical behavior of API 5L X70 ageing. Bending test specimens underwent solution treatment in an electric induction furnace at 1100°C for 30 min under argon atmosphere and water quenching and then ageing process for five temperatures in the range between 204 to 650°C for 30 min of time exposition and water quenching, respectively. The microstructural characterization was examined by scanning electron microscopy (SEM) and matrix samples ageing showed microstructures, acicular ferritic, polygonal ferrite, bainitic-ferrite, degenerate perlite and retained austenite and energy dispersive spectroscopy (EDS) evidencing the presence of carbonitrures type Nb, Ti, V (N, C). Hydrogen was introduced in a sample of bending test, through cathodic charging, applying a current density of 50 mA/cm2. Three point bend test was carry out on specimen on API X70 with and without hydrogen and the result showed a reduction of ductility and 65% of index of embrittlement (IH). Also, samples undergoing ageing with hydrogen showed an increase in bending stress compared to a sample undergoing ageing without hydrogen, and the parameter (IH) decreased in the range of 21 to 29% due to the formation of traps. The fracture surface of bend tested samples were examined using a SEM.
Concentration Dependence of the Diffusion in the Ni/Cu System
Authors: Balogh Zoltán , Chellali Mohammed Reda , Stender Patrick , Schmitz Guido
Published: May 2014

Deviations from the Fickian-laws of diffusion in the case of concentration dependent diffusion coefficients and high composition gradients gain more and more acceptance nowadays. The cause of this phenomenon is the finite permeability of the atomic layers, or in other words “interface control”. The consequences are wide-spreading e.g. linear diffusion kinetics, deviations in the nucleation behavior of reaction products and kinetically determined interface shape in miscible alloys. Furthermore, if the original chemical interface is broader than the optimum width, even a sharpening of the interface by diffusion can be observed. Previous experiments proving these effects used more or less ideal specimens (e.g. single crystalline or amorphous samples with very flat interfaces) and some doubts can be raised whether these effects can be observed in a realistic specimen with a more complex grain structure. In this talk we will present the results of atom probe measurements on sputter deposited Ni/Cu multilayers (containing surface roughness, lattice defects, etc.). Samples with sharp and smeared Ni/Cu interfaces were produced and later annealed. We found an asymmetry on the interface width in the as-prepared specimens depending on the stacking order. After annealing this asymmetry vanished and remarkably the Cu/Ni interface sharpened by diffusion. After short diffusion time, the interface width became independent on the sample origin (sharp or smeared interface) proving the kinetic control of the interface. Atom probe tomography also allows the direct, local investigation of the grain boundary diffusion in any single grain boundaries. Surprisingly the best description of the shortcut transport can be achieved by assuming a concentration-independent grain boundary diffusion coefficient.
Irradiation Effect on Ta2O5 Thin Films
Authors: Baydogan N. , Erkan B. , Tugrul A.B. , Cimenoglu Huseyin
Published: May 2014

Long-term effects of time-dependent solarization behavior on optical density and optical band gap of the gamma and beta irradiated Ta2O5 thin films were investigated to examine the optical aging of films at different absorbed dose levels. Irradiation process caused to induce defect centres. The population inversion of the colour centres was increased by controlling the absorbed dose at certain radiation dose levels. The efficient absorption of photons in tantalum reduced transmittance. The grain boundaries of the Ta2O5 thin film decreased at the end of irradiation process. The average grain boundaries changed after the irradiation process at 4.5 kGy and average grain boundaries decreased from ~ 11.5 to 5.5 μm. The optical fading behavior of induced color centers addressed to the potential opportunities of Ta2O5 thin film by monitoring absorption of photons in optoelectronic technology. Optical fading of the Ta2O5 thin film presented an importance to investigate the material stored ionizing radiation dose in it with the increase of elapsed time after the irradiation treatment.
Microstructure of Sodium or Potassium Added Mg-Ni Eutectic Alloy
Authors: Saitoh Hideyuki , Shiraishi Y.
Published: May 2014

The microstructure of sodium or potassium added Mg-23.5 mass%Ni eutectic alloy was observed and the effect of sodium and potassium addition on the eutectic structure was investigated. All alloys showed the eutectic structure which composed of Mg phase and Mg2Ni phase, and no evidence of the sodium or potassium precipitation occurred. For the sodium added and furnace cooled alloy, the lamellar spacing in the eutectic structure became a little narrow and the Mg2Ni phase tends to become fragmentary as the amount of sodium increases. The sodium addition has a little effect for the refinement of the eutectic structure. For the potassium added and furnace cooled alloy, the lamellar spacing of the eutectic structure became clearly narrow even by the 0.1 mass% potassium additions. The morphology drastically varied in more than 0.5 mass% potassium added specimens, that is, the refinement and fragmentation of the Mg2Ni phase occurred. The potassium addition has a large effect for the refinement and the fragmentation of the Mg2Ni phase in the eutectic structure. For the water quenched specimens, the eutectic structure was extremely fine and globular shape with and without the additive element. The refinement effect by the water quenching is remarkably high even as the non-added specimen. The effect of sodium and potassium addition on the refinement of eutectic structure is not clear in the case of the rapid cooling speed during solidification.
The Synthesis of High-Surface Area Silicon Carbide by Conversion Method Using Carbosilane Polymer
Authors: Jung Eun Jin , Lee Yoon Joo , Kwon Woo Teck , Kim Y. , Shin Dong Geun , Kim Soo Ryong
Published: May 2014

Since mesoporous silica such as MCM-41 and SBA-15 was developed, the study of the properties of high-surface area materials was accelerated. Moreover, the mesoporous silica is used as a template to produce high-surface materials by nanocasting technology. The purpose of this paper is the synthesis of a high surface silicon carbide sphere by the nanocasting technology. In this study, KCC-1 silica sphere was used as a template, and polycarbosilane and poly (phenyl carbosilane) were selected for precursor of silicon carbide. Carbosilane polymer gives advantage of synthesis silicon carbide under low temperature, and hollow spheres were produced. In this study, the polycarbosilane was more effective for the synthesis of SiC hollow spheres by inversion of template structure showing a fibrous morphology on the sphere wall. And it was confirmed that the sphere was composed of nanosized SiC crystals, and has high surface area using TEM, XRD and BET analysis.
Methane Diffusion in a Porous Environment
Authors: Staša Pavel , Kohut Vladimír , Kodym Oldřich , Jančíková Zora
Published: May 2014

The paper deals with modeling and simulation of methane flow through the porous environment using the CFD (Computational Fluid Dynamics) software Fluent. We compare three situations, which can occur in areas, where mining activities were closed few years ago, in this article. First case is modeling of methane flow through the rocks. Second event is situation where the thin water layer is situated at the surface. The last one is occurrence of groundwater. The article responds to the need for knowledge of natural processes in the given area and it follows our previous papers [1], [2]. Software Gambit was used for creating a geometric model of the working area, for modeling the flow of gas it was used CFD software, Fluent from ANSYS, Inc..
Visualization of Thermal Measuring in 3D Environment
Authors: Kodym Oldřich , Kohut Vladimír , Koštial Pavel , Jančíková Zora
Published: May 2014

Measuring of thermal distribution in certain material was done in Matlab. Obtained data are processed and displayed in fully 3D environment (virtual reality) using X3D. Paper deals with data processing and conversion from Matlab into X3D. Further development of visualization is discussed too – visualization of thermal gradient, Integration of measured a visualized data into real object or technological process visualization. The aim of this topic is to present information about discontinuities in solid materials.
Design and Analysis of Concentrated Solar-Energy Assisted Paddle Dryers
Authors: Du Jiang Yong , Liu Xin Zhi , Zhang Hou Lei
Published: May 2014

Paddle dryer, one kind of indirect dryers, is widely used in removing moisture content of many materials, such as brown coal, sewage sludge, and biomass. For many applications, the materials to be dried are low-valued or even wastes, so the drying energy consumption becomes the critical issue. One way to reduce the energy consumption is to introduce solar-drying technology. In this paper, firstly, we present a paddle dryer system configuration with concentrated solar energy (CSE) device, which consists of trough-type collectors, thermal storage tanks and auxiliary parts. Then a calculating model is developed to design the drying system. Examples with typical solar radiation conditions in Nanjing, China are illustrated. The energy-saving rate (η), i.e. the ratio of the provided solar energy to the total energy required by the drying process on one-day basis, is evaluated. The developed lab prototype is finally described in brief.
The Multi-Breakage Phenomenon in Air Bending Process
Authors: Vorkov Vitalii , Aerens Richard , Vandepitte Dirk , Duflou Joost R.
Published: May 2014

In this work, the multi-breakage effect has been studied by means of an experimental campaign and finite element analysis. We suggest that large radius bending (XL-bending) consists of three phases that are distinguishable according to the type of contact of the plate with the tool: 1-point, surface and 2-points. In the experimental investigation the high-strength steel Weldox 1300 and a 40 mm radius punch were used. The authors created a camera setup to film the multi-breakage effect. Additionally, finite-element calculations were performed to confirm the hypothesis of the three phases of the bending process. For the springback and the bending force evaluation, the difference in the moment distribution for each phase has been calculated in the case of a beam. It shows that the multi-breakage effect must be taken into account to obtain a good accuracy for the springback and the bending force calculation.
Phase Transformation and Microstructural Behavior of New Steel Grades for Hot Sheet Stamping
Authors: Bruschi Stefania , Ghiotti Andrea , Valoppi Beatrice , Puerta-Velasquez Juan David , Drillet Pascal , Arribas Maribel , Aranguren Iñigo , Clobes Joerg
Published: May 2014

Since the last few years several researches have focused in proposing new approaches to decrease the energy impact of the hot sheet stamping process. Among them, one possibility is to use steel grades characterized by a lower austenitization temperature in order to reduce the heating energy required for the process, but still maintaining the steel quenchability under the investigated process conditions. In the paper, the behaviour of two new steel grades developed by ArcelorMittal and devoted to hot stamping is investigated in terms of transformation kinetics and microstructural behaviour. An extensive dilatometric analysis, performed by using a modified axial extensometer, permitted to evaluate the steel kinetics of phase transformation as a function of the applied cooling rate, amount of strain and strain rate. The micro-hardness of water and die quenched samples of the investigated steel grades was measured and their microstructure analyzed by means of optical and scanning electron microscopy to evaluate the characteristics of the formed martensite and the possible phenomenon of autotempering.
Surface and Microstructure Considerations in High Speed Single Point Incremental Forming of Ti6Al4V Sheets
Authors: Ambrogio Giuseppina , Bruschi Stefania , Gagliardi Francesco , Ghiotti Andrea , Filice Luigino
Published: May 2014

Flexible sheet metal forming processes represent a big challenge, which involved a number of researchers all over the world in the last decades. Among these, Incremental Sheet Forming (ISF) process is one of the most investigated and promising due to its simplicity, cheapness and applicability. Furthermore, the possibility to increase the process velocity makes the ISF more suitable than in the past; as a consequence, its application potential is surely increased. It was already highlighted that high speed significantly raises the process temperature, improving the workability of Titanium alloys. In this process configuration, no further heating source is strictly required because the temperature increase is generated due to the plastic deformation and the friction conditions at the interface between the punch and the sheet. While the process feasibility has been already investigated, a lack of knowledge in the literature is present focusing on the analysis of the process impact on the material properties. Accordingly, an experimental campaign on Ti6Al4V sheets has been performed, considering a punch speed two orders of magnitude higher than the conventionally used one. The obtained surfaces have been compared to sheets worked by traditional velocity in order to accurately analyze the impact of high speed. Furthermore, microstructural analyses have been carried out confirming the high speed suitability. All the details are reported in the manuscript
Approach for Implementation of Short Cycle Stretch Forming (SCS) to Cupping Processes
Authors: Schneider Matthias , Liewald Mathias
Published: May 2014

Short Cycle Stretch Forming (SCS) is a new stretching process patented by the Institute for Metal Forming (IFU) of the University of Stuttgart in 2006 [. It was mainly developed for outer car panels like doors [ and roofs [ with the aim of: