bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Study of Natural Draft Wet Cooling Tower
Authors: Zheng Shui Hua , Jin Tai , Fan Jian Ren
Published: December 2011

Natural draft wet cooling tower is one of key equipments in thermal power stations, and its thermal performance influences the efficiency of total thermal system. Based on the heat and mass transfer theory and characteristics of the FLUENT software, a three-dimensional numerical simulation platform had been developed to simulate the thermal performance in a natural draft wet cooling tower. This platform was used to study the heat exchange and flow situation of a typical hyperbolic natural draft wet cooling tower. Comparing and analyzing the results of simulation and design calculation, it indicate that there is good computational accuracy of the three-dimensional numerical simulation platform, and the platform can provide a good support for the design and research of natural draft wet cooling tower.
An Approach to Obtain Software Security Vulnerabilities Based on Vertical Search
Authors: Li Xiao Hong , Hu Chang , Feng Zhi Yong , Du Hong Wei , Ding Gang Gang
Published: December 2011

we propose an effective approach to obtain software security vulnerabilities in web with vertical search technique in this paper. We use a keyword-trainer to get domain keywords in software security domain. Then the web page filter is designed after analyzing the obtained domain keywords and the structure of the URL topology. Finally, we design a vertical search crawler based on the webpage filter to search for the information of software security vulnerabilities in Web. This approach effectively discovers and digs out the information of software security vulnerabilities presenting in Web. It helps provides the primary knowledge and information for constructing security-knowledge database and analyze the vulnerabilities of software.
Semantic Interpretation of the Answers of Elementary Algebra Proving Problems
Authors: Li Bing , Yang Yi , Li Lian
Published: December 2011

This paper describes the semantic interpretation of a restricted language in a system which automatically assesses the answer of a proving problem of elementary algebra in Chinese. The system translates a student’s proof into a formal one which can be verified in Isabelle/Isar automatically. The correctness of the original proof is equivalent to the formal one obtained from the translation.
An Evaluation and Analysis on High-Tech Industry Competitiveness in Fujian
Authors: Shi Sheng Xu , Wu Sheng Yi
Published: December 2011

By establishing the high-tech industry competitiveness evaluation index system, we apply the factor analysis and cluster analysis methods to evaluation and analysis on high-tech industry competitiveness in East China of six provinces and one city. The result shows that the comprehensive score of Fujian stands at the lower level in the whole country, but the efficiency ability, innovation and effect ability factors rank up the average level. So we suggest that Government should adjust the industrial and regional structure, develop the high-tech industry branding and standardized and so on to promote the development of the high-tech industry and then improve its competitiveness in Fujian.
Investigation of the Impact of Smart Packaging on Performance in Deteriorating Items Supply Chain
Authors: Fard Ali Rahimi , Yegane Babak Yousefi
Published: December 2011

The Packaging sector is an important global industry, representing about 2% of the Gross National Product of the developed countries. In recent years deteriorating items packaging such as food and pharmacy packaging has been developing by high speed, attempting to product safety, shelf-life of products, environmental condition and consumer convenience. So the new initiative methods have been studying and implementing to develop the function of this industry which smart techniques for packaging are samples of this method. This techniques have high power for security the quality or safety of deteriorating items by using the less additives or deteriorate prevented materials that cause the reduce within of the waste, venom and allergies. Smart systems can increase production efficiency, precise and continual and surveillance, product pursuit wherever at supply chains and finally increases the safety factor of consuming safe product and reduces the protests from consumer. The fundamental point is that how we use this technique to improve the system condition. In this research we survived the effect of implementing smart packaging on inventory control also the system has been compared before and after implementing the smart packaging by using mathematical model.
Fabrication of Microlens and Microlens Array on Polystyrene Using CO2 Laser
Authors: Fan Yi Qiang , Li Hua Wei , Foulds Ian G.
Published: December 2011

This study presents a new process for fabricating microlens and microlens arrays directly on a surface of polystyrene using a CO2 laser. The working spot of the polystyrene is heated locally by a focused CO2 laser beam, which tends to have a hyperboloid profile due to the surface tension and can be used as a microlens. The microlenses with different dimensions were fabricated by changing the power of the laser beam. Microlens array was also fabricated with multiple scans of the laser beam on the polystyrene surface.
Postbuckling Investigation on the Micromachined Double-Clamped Beams
Authors: Chen Xing , Ma Lian Sheng , Zheng Ying Mei , Wang Bo , Lee Dong Weon
Published: December 2011

In this paper, thermal postbuckling of a beam-like structure subjected to a uniform thermal loading is studied both theoretically and experimentally. In theory aspect, the equations governing the axial and transverse deformations of beams are derived. The two equations are reduced to a single nonlinear fourth-order integral-differential equation governing the transverse deformations. The analytical method presented here offers a simple yet efficient solution approach to analyze the bistable behavior of microbeam or beam-like structures under thermal loading. Then, microfabricated double-clamped beams are chosen as experimental object due to its precise dimensions and easy loading method. The lab-made HF vapor system was used to release the suspended structures with satisfactory results. After the fabrication and measurement, by comparing the theoretical results with experimental results, an excellent agreement is gotten. It proves not only the validity of the solution obtained here, on the other hand, importantly, it also demonstrates a new field for MEMS as another easy and accurate tool to investigate mechanics problems. With the accurate solutions for posbuckling beams, we apply it into new electrothermal postbuckling actuators, a big deflection promising the possibility of a new kind of actuator.
Research on the Time Factor of Li-Ion Battery for Vehicle-to-Grid (V2G) Implementation and Charging Station Application
Authors: Shi Wei , Jiang Jiu Chun , Lin Si Qi , Jia Rong Da , Wen Jia Peng
Published: December 2011

An outline of electric vehicles industry in the national smart grid plan and a conceptual framework for the vehicle-to-grid implementation in China is presented, and the relationship between battery energy package and smart grid is also discussed in this paper. The analysis and research based on the energy package management and charging station requirements are stated. This paper also does research on reasonable charge and discharge of the Li-ion battery with the performance degradation, which are the key issues of the development of electric vehicles. At last the paper will discuss briefly on the fast charge method, which saves time of charge battery and favors life span of battery system. When plenty of electric vehicles connecting to the grid, advanced energy scheduling and optimization control strategy of Li-ion battery demand consideration of time factor and the gird needs.
A Low Complexity Multivariate Regression Based Flood Forecasting Model Using an Optimized WSN Deployment Scheme
Authors: Raha Arnab , Maity Shovan , Mitra Souvik Kr. , Jana Ramesh , Naskar Mrinal K.
Published: December 2011

Very recently work has been done to develop efficient disaster forecasting systems utilizing WSN technology. Such networks pose a tremendous design challenge such as the ability to cope with node failure, limited power, distributed prediction, wide variety of sensors and the need for communication over a large area. Our paper introduces a Predictive Environmental Sensor Network (PESN) Architecture which employs a minimal deployment scheme to ensure connectivity among the nodes involved within the network. On this connected network we run our distributed statistical model for forecasting. The statistical process used for this real time prediction uses multiple variable regression method providing the advantages of simplicity and robustness much needed in low power and limited ability sensor nodes. The versatility of the forecasting model is proved on its independence on the number of parameters, as it can incorporate as many variables into the algorithm as required, as long as there is sufficient positive correlation with the instantaneous river water level.
Identification of Nolinear Systems Using Inceremnetal and Diffusion Differential Evolution Algorithms
Authors: Thethi H. Pal , Majhi Babita , Panda G.
Published: December 2011

The paper investigates on the use of Differential Evolution (DE) for training the system identification model particularly when the measurement data are available at different sensor nodes. Under such situation the conventional DE algorithms cannot be applied directly. Hence in this paper two distributed learning algorithms known as incremental DE (IDE) and diffusion DE (DDE) have been developed to meet the requirements. The identification of nonlinear plants under different noise conditions has been obtained through simulation study and the results have been compared with distributed PSO algorithms. The performance of the proposed algorithms in terms of convergence rate and minimum mean squared error indicate that the distributed DE algorithms exhibit superior performance compared to its PSO counter parts.
Modeling the Performance of an Industrial Process Based on Neural Networks and Data Mining
Authors: Aghvami S. Sara , Shandiz Heidar T. , Motlagh M.R. Jahed
Published: December 2011

Data Mining has been applied to the world of industrial process. Through this paper, modeling of such a process, a boiler, is discussed focusing on the two methods of Partial Least Square (PLS) Regression and Neural Networks. In modeling the system behavior, the former has the capability of reducing the database dimension and taking to account the latent relations between data, while the later handles the nonlinearity of the process in order to predict the system response through the database of observed boiler operation data.
Web Based Application Maintenance Cost Estimation Modeling Using Bayesian SEM
Authors: Prakancharoen Somchai
Published: December 2011

The objectives of this research were to find out the Structural equation modeling coefficient and other parameter estimation under unknown prior distribution and compare this new model’s coefficient accuracy with the former model on “Web based application maintenance cost estimation multi group modeling” [16]. This new coefficient and parameter were estimated with Bayesian analysis instead of Maximum likelihood estimation (ML). The input model used in Bayesian analysis was started from the ML-model result [16]. The new values were replaced into the former model then MMRE was detected from 30 (testing) completed software maintenance projects while 192 projects were used for SEM model training. The result of cross validation was about 44.08% for Bayesian analysis refined SEM model while the ML-SEM model was 47.58%.
Quality Assessment in Vocational Education Based on a Hierarchical Classification Technique
Authors: Ekwong Chantima , Wichain Sageemas Na , Haruechaiyasak Choochart
Published: December 2011

According to the laws of education in Thailand, the Office for National Education Standards and Quality Assessment is responsible for assessing the external educational institutes in order to develop the quality and educational standards. The external quality assessment reports are represented in both structured and unstructured data. In this paper, we focus on the analysis of unstructured data, i.e., to automatically classify strength and weakness points. We propose and evaluate two different classification models: Flat Classification and Hierarchical Classification. Three algorithms, Naive Bayes, Support Vector Machines (SVM) and Decision Tree, were used in the experiments. The results showed that classification viathe Hierarchical Classification model by using the SVM yielded the best performance. The classification of strength and weakness points yielded the F-measure equal to 0.843 and 0.893, respectively. The proposed approach can be applied as a decision support function for quality assessment in vocational education.
Robust PD State Feedback Controller Design for Uncertain Singular Systems
Authors: Zhu Jian Wu , Ding Yuan Chun
Published: December 2011

This paper is concerned with the problem of robust stability and stabilization of singular systems with uncertainties in both the derivative and state matrices. By using a parameter dependent Lyapunov function, we derive the LMI-based sufficient conditions for the stabilization of the singular systems. Secondly, by solving these LMIs, a proportional plus derivative (PD) state feedback controller is designed for the closed-loop systems to be quadratically normal and quadratically stable (QNQS). Finally, the numerical example is given to show the effectiveness of the proposed theorems.
The Optimization Design Method of Multivariate Control Chart with Adaptive Sample Size
Authors: Wang Hai Yu
Published: December 2011

ARL (Average Run Length) is used as a tool to measure the performance of control chart. But it isn’t very accurate. In this paper, APL (Average Product Length) is used as a criterion of multivariate control chart performance assessment and a multivariate chart with adaptive sample size is proposed. A Markov chain method is proposed to calculate the APL of multivariate chart with adaptive sample size and then the optimization design method of this chart is discussed. By comparing with traditional fixed sample size design method, we can find that this method have higher efficiency.
Design and Simulation of RF-MEMS Tunable Capacitors Using Multiple Voltage Sources
Authors: Mohabbatian Neda , Abbaspour Sani Ebrahim
Published: December 2011

A novel tunable RF-MEMS variable capacitor(varactor) is presented. The Flip -Flop structure of the design makes it possible to either increase or decrease the capacitance. Dimensions, sizes and the materials used in the device are chosen so that it can be manufactured in Urmia MEMS Lab. Silicon surface micromachining thechnology is used for the structure, which is CMOS compatible. Electrostatic actuation method is selected because of it's low power consumption so it can be used in low-power wireless applications. The value of the capacitor is changed by varying the gap between the two plates. Tuning voltage is in the range of 0-2 volts. The capacitor has the initial value of 0.43pF, maximum value of 0.92pF and minimum value of 0.3pF. Actuation and varactor plates are separate from each other. The structure is simple and can be fabricated by employing only 3 masks.
Leakage Process and Minimization -Transistor Stacking Effect, Data Retention Gated Ground Cache, Drowsy Cache
Authors: Mukherjee Debasis , Reddy B.V.R.
Published: December 2011

Leakage Current is found to be gradually increasing in CMOS VLSI circuits with advance of technologies, specially in nanometer range. Though area of a transistor is becoming less and lesser, but precious control over the operations of a transistor is not possible in such a small structure. Reductions of threshold voltage, channel length, and gate oxide thickness are responsible for generation of leakage current. In this paper we have reviewed eight types of leakage current present in CMOS VLSI circuits, namely 1. Reverse Bias pn Junction Current, 2. Sub-threshold Leakage, 3. Drain Induced Barrier Lowering Effect, 4. Gate Induced Drain Leakage current, 5. Punch Through, 6. Narrow Channel Effects, 7. Gate Oxide Tunneling leakage current and 8. Hot-Carrier Injection. After that, we have reviewed 6-T SRAM read and write operation. Next to that, we have reviewed three techniques of leakage reduction namely 1. Transistor Stacking Effect, 2. Data Retention Gated-Ground Cache and 3. Drowsy Cache. We have reproduced the simulation result of these leakage minimization techniques. Finally we have shown comparison of 1. Conventional 6-T SRAM leakage current, 2. leakage current using Data Retention Gated-Ground Cache techniques and 3. leakage current using Drowsy Cache techniques. To obtain these three results we have used Cadence Virtuso & SoC Encounter tools. All these three results has been simulated with IBM 90 nanometer technology file.
Rapid and Low-Cost Fabrication of Polystyrene-Based Molds for PDMS Microfluidic Devices Using a CO2 Laser
Authors: Li Hua Wei , Fan Yi Qiang , Foulds Ian G.
Published: December 2011

In this article, we described a rapid and low-cost method to fabricate polystyrene molds for PDMS microfluidic devices using a CO2 laser system. It takes only several minutes to fabricate the polystyrene mold with bump pattern on top of it using a CO2 laser system. The bump pattern can be easily transferred to PDMS and fabricate microchannles as deep as 3µm on PDMS.
Design and Analysis of Novel Four-Quadrant Double Liquid Lens Based on EWOD
Authors: Hu Xiao , Li Jiu , Liu Jin Feng , Huang Zi Qiang
Published: December 2011

A novel double liquid lens based on Electrowetting-On-Dielectric (EWOD) is presented and analyzed. The special construction is that the lens was divided into four quadrants. The particular fabrication process is presented to achieve the structure. It was proved that the lens not only expressed the electric zoom character but also shifted focal point away from optical axis. It also achieved an infinite focal length under zero electric field. The paper presented the relationship between the focus length and applied voltage, also gave the association between focus length and the applied voltage from 0V to 80V. We analyzed how the optical axis shifted according to the voltage difference between quadrants, furthermore, explained the new function that the focus object was away from center of lens.
Plasma Dispersion Effect for Various Doping Configuration on the SOI Phase Modulator with Trapezoidal Rib Waveguide
Authors: Mardiana B. , Hanim A.R. , Hazura H. , Shaari S. , Menon P. Susthitha , Abdullah Huda
Published: December 2011

Silicon-on-insulator (SOI) is becoming more attractive as a photonic material for photonic integrated circuits (PLC) because of its unique features. In this paper, we modeled and simulated the performance of the SOI phase modulator with various doping configuration based on the plasma dispersion effect. The effect of the free injected carrier in the region of the propagating optical mode have been investigated at the optical wavelength of 1.55µm. The proposed device have been integrated in the SOI rib waveguide with trapezoidal cross section structure and four different doping configurations have been chosen which are the n+p+n+, p+n+p+, n+n+p+and the p+p+n+. Our results show that the n+n+p+configuration possessed the best modulation efficiency of 0.026V.cm and gained the smallest absorption loss of 1.1dB at 0.95V applied voltage.
Fabrication and Test of Electrostatic MEMS Converter Found in Energy Scavenging Systems
Authors: Salem Marwa S. , Tasciuc Diana Borca , Zekry A.A. , Ragai H. F.
Published: December 2011

This paper introduces the steps for fabricating an electrostatic MEMS converter found in energy scavenging systems. The fabrication carried out at Rensselaer Polytechnic Institute (RPI) clean room, Troy, New York, USA. The testing results for the fabricated converter are presented. The main objective of fabricating and testing the electrostatic MEMS converter is to verify the new idea of enhancing its output power by including the effect of its parallel capacitance in the output power equation.
Research of Chemical Film Process on Metal Surface
Authors: Chen Ze Min , Lu Pin , Du Yu , Lu Ya Ping
Published: December 2011

In the article we selected polyethylene glycol(400), triethanolamine, silane coupling agent, chrome alum, glycerin as the main raw material, and systematic studied the chemical adsorption film technology on metal surface by using one step. Through the preliminary experiments, we optimized the optimum technological conditions. The trial results showed that the process and procedures to deal with were simply, and the tank liquor was stable. The chemical adsorption film accumulation was closely, and it had stable structure. It had a good anti-base metal corrosion, and significantly enhanced the adhesion of metal coatings.
Theoretical Charge Control Investigations in InN-Based Quantum Well Double Heterostructure High Electron Mobility Transistors (QW-DHEMTs)
Authors: Kaysir Md. Rejvi , Islam Rafiqul
Published: December 2011

In this paper, charge control mechanism and carrier features have been precisely investigated in InxGa1-xN/InN/InxGa1-xN based quantum-well double heterostructure high electron mobility transistors (QW-DHEMTs). A study of charge control in the InxGa1-xN/InN/InxGa1-xN structure is performed by self-consistently solving Schrödinger equation in conjunction with Poisson’s equation taking into account the spontaneous and piezoelectric polarization effects. The potential profile and the distribution of electron density in the channel as a function of gate voltage are investigated here. A large conduction band offset of about 2.2eV is obtained for the proposed device for In content x=0.05, which ensure better carrier confinement and higher sheet charge density. The influence of In composition(x) and doping concentration of InxGa1-xN upper barrier on sheet charge density and carrier distributions in channel is also presented. This analysis provides a platform to investigate the InN based QW-DHEMTs and to optimized their design.
Application Research of Internet of Things Technology in China Post Modern Logistics Warehouse Management Based on RFID
Authors: Wei Xiao Xiao
Published: December 2011

Based on theories of modern post logistics and the internet of things, and combined with the needs and characteristics of China’s post logistics, this thesis has analyzed role of RFID-based internet of things in modern post logistics management, and designed and developed a China Post modern logistics warehouse management information system based on RFID so as to help China Post Modern Logistics (CNPML) enterprises improve their automation level, minimize production and operational costs, and create more economic and social benefits.
Process Simulation Research of CH4/N2 Separation
Authors: Zhang Gao Bo , Fan Shuan Shi , Lang Xue Mei , Wang Yan Hong
Published: December 2011

The separation energy consumption of methane and nitrogen mixture of 3 kinds of typical method, Cryogenic (DC), Pressure Swing Absorption (PSA) and Membrane (MEM), was calculated by Aspen Plus in this paper. The result shows that at 35°C, the ratio of methane and nitrogen is 1, the separation energy consumption of 3 methods are 5.2, 3.6 and 2.6×104kJ/kmol, respectively. The ratio of calculated energy consumption to theoretical consumption is 2.3, 1.6 and 1.2, the energy consumption of DC is the highest, then PSA, MEM is lowest. This work is to give some reference for the selection of CH4/N2 separation.
Treatment of Tannery Wastewater with Salt Tolerant Bacteria Basing on Different Culture Mediums
Authors: He Jun Guo , Liu Fei , Han Bao Ping , Zhao Bo Wei , Liu Jian
Published: December 2011

This study was done to access the influence of salinity on the treatment of tannery wastewater, activity of sludge and morphological characteristics of the salt-tolerant bacteria cultivated using tannery wastewater as culture mediums and intermittent aeration as method. The results indicated that， aerobic sludge which contained salt-tolerant bacteria was cultivated under the conditions of temperature of 35°C and pH = 8, the COD removal in simulated and actual tannery wastewater was more than 87% and 85% by the cultivated aerobic sludge, respectively. In addition, the morphological characteristics were related to the composition and concentration of the salt. The average generation time of bacteria was 24.6min ~ 28.6min when the concentration of MLSS was 2.0 ~ 3.0g/L and the concentration of pure NaCl was 1 ~ 5g/L. As the volume ratio of NaCl and Na2SO4 was 4:1 ~ 1:4 with the total concentration of 5g/L, the average generation time of bacteria was 30.8min ~ 39.7min. The relation equation between salt concentration and the average generation time of bacteria under the pure salt, composite salt and actual tannery wastewater conditions was also deduced through four assumptions. The results had significant application on tannery wastewater treatment with great reduction of pollution.
Material Intrinsic Length in Plastic Strain Gradient Theory and Microbending Process of Metal Foils
Authors: Li He Zong , Dong Xiang Huai , Huang Su Xia , Diehl Alexander , Hagenah Hinnerk
Published: December 2011

In microbending experiments of metal foils an increase of non-dimensional bending moment with decreasing foil thickness has been observed, which indicates the obvious presence of size effects. It is attributed to plastic strain gradient. So a constitutive model taking into account plastic strain gradient together with conventional plastic strain hardening is proposed to analyze the non-dimensional bending moment in microbending process. It is confirmed that the predictions by using the proposed hardening model agree well with the experimental data, while those determined by using conventional elastoplastic model cannot capture such size effects. A semi-empirical expression is reasonable to determine the material intrinsic length as a function of shear modulus, initial yield strength, length of Burger’s vector, grain size, and macro geometrical characteristic scale of the specimen.
Active SOI Optical Ring Resonator Based on Free Carrier Injection
Authors: Mardiana B. , Hanim A.R. , Hazura H. , Shaari S. , Menon P. Susthitha , Abdullah Huda
Published: December 2011

This paper highlights the study of the free carrier injection effect on the active SOI optical ring resonator. The effect of the free carrier injection on optical ring resonator was evaluated by varying the p+ and n+ doping concentrations. The device performances are predicted by using numerical modelling software of the 2D SILVACO and Finite Difference Time Domain method simulation software RSOFT. The results show the refractive index change increases as the p+and n+doping concentrations is getting higher. A shift in resonant wavelength of around 2 nm was predicted at 5x1019cm3p+and n+doping concentrations with 5.8x10-3refractive index change. It is also shown that 8.2dB change of the output response obtained through the output.
A New Combination Rule for the Fuzzy Risk Assessment in Gas Pipelines
Authors: Doremami Nadia , Afshar Ahmad , Doust Mohammadi Ali
Published: December 2011

In this paper, a general framework is given for risk assessment. As a case study, leakage risk in gas transmission pipelines has been considered. To estimate the risk, two main terms are defined: "severity" and "likelihood of occurrence", both of which are associated with uncertainty. By use of "fuzzy set theory", these uncertainties have been modeled. In order to estimate the risk for the whole pipeline, it is divided into a number of segments. To aggregate the calculated segment's risk values, the new combination rule is proposed. This is necessary because in cases of high conflict between the evidences source and their null intersection, this theory does not provide a sensible outcome. To remedy these problems, in this paper, a new method for data aggregation has been proposed. Simulation results indicate the better performance of the proposed method compared with the original combination rule of Dempster-Shafer theory in risk assessment.
Image Processing of Ultrasound Color Doppler to Characterize Malignant Breast Lesion
Authors: Chatterjee Subarna , Karim Rezaul , Biswas Arindam , Ray Ajoy Kumar
Published: December 2011

Breast cancer, the most common cancer in women, is one of the major causes for the increase in mortality among women especially in developed countries. Doppler ultrasound is an important noninvasive diagnostic tool for identifying breast malignancies. We present a novel technique for segmenting blood vessels in ultrasound color Doppler images based on image processing techniques. The proposed technique decomposes a complex object representing either two or more vessels artificially linked together or a main vessel with its branches. We segment out the blood vessels in ultrasound color Doppler images and count the number of vessels to detect breast malignancy. Matlab has been used to simulate the algorithm and the results obtained are presented in this paper. The result represents distinct vessels that can be used in further object recognition and quantification applications.
Spectral Splitting of Speech by Wavelet Packets to Shrink Simultaneous Masking
Authors: Dhulekar P.A. , Nalbalwar S.L. , Chopade J.J.
Published: December 2011

Simultaneous masking is when a sound is made inaudible by a masker, a noise or unwanted sound of the same duration as the original sound. An innovative approach is investigated for speech processing in cochlea. Differently from the traditional filter-bank spectral analysis strategies, the proposed method analyses the speech signal by means of the wavelet packets. Splitting the speech signal by filtering and down sampling at each decomposition level, using wavelet packets with different wavelet functions, helps to shrink the effect of simultaneous masking. The performance of the proposed method is experimentally evaluated with vowel-consonant-vowel -syllables for fifteen English consonants. The dichotic presentation of processed speech signals effectively reduces the simultaneous masking through which it improves auditory perception.
Microstructure Control and Mechanical Properties of 7075 Aluminum Alloy by Means of Multi-Pass Friction Stir Processing
Authors: Matsuda Yutaka , Itoh Goroh , Motohashi Yoshinobu
Published: December 2011

Friction stir processing (FSP) is a method for controlling the microstructure that has been proposed by applying friction stir welding, FSW. In this study, microstructure and mechanical properties of a 7075 aluminum alloy subjected to multi-pass FSP, MP-FSP, are assessed to obtain fundamental knowledge for improving the plasticity of aluminum alloys. The MP-FSP has been applied to 7075 alloy plates with T6 and O tempers, and microstructural characterization has been made by means of optical and scanning electron microscopies together with EDX and EBSD analyses, while mechanical properties were measured by means of micro hardness and tensile tests at room and high temperatures. From microstructural observation, a new zone, PBZ, has been discovered between stir zones, SZs. The PBZ is composed of two types of (fine and coarse) grains, where the coarse grain contains many sub-grains. Hardness in PBZ is intermediate between that in BM and SZ both in T6 and O specimens; hardness generally decreases and increases in T6 and O specimens, respectively, by MP-FSP. In accord to the hardness change, strength at room temperature is decreased by MP-FSP in T6 specimen, and increased in O specimen. Elongation at 773K is increased both in T6 and O specimens because of superplastic deformation. However, local elongation is smaller in PBZ than in SZ, which can be attributed to the microstructural change by the deformation: grain shape remains equiaxed in SZ while it becomes elongated in the tensile direction in PBZ.
HRTEM Observation of the Age Hardening Precipitates in Mg-Gd-Sc Alloys, with Different Gd Concentrations
Authors: Fujii Takafumi , Matsuda Kenji , Kawabata Tokimasa , Ikeno Susumu
Published: December 2011

High resolution transmission electron microscope (HRTEM) observations were performed to investigate the age hardening precipitates in Mg-Gd-Sc alloys. The maximum hardness of these alloys increased with Gd content. The precipitates with the features of β” phase and β’ phase in Mg-Gd alloy were observed in Mg-15Gd-6.4Sc and Mg-10Gd-6.4Sc alloys. Maximum hardness and number density of precipitate in Mg-15Gd-6.4Sc alloy were higher than that in Mg-10Gd-6.4Sc alloy, and the finer precipitates with higher number of density were contributed to the maximum hardness in Mg-Gd-Sc alloys.
Effect of Zn Contents on Microstructure in AZ-Series Magnesium Alloys
Authors: Narukawa Yuichi , Watanabe Katsumi , Matsuda Kenji , Kawabata Tokimasa , Ikeno Susumu
Published: December 2011

Magnesium alloys containing Al have been used for industrial materials due to their lightweight and recyclability. The Mg-Al alloys are usually used for the industrial production. The Mg-Al alloys are divided into AZ-series alloys with the addition of Zn, and AM-series alloys with the addition of Mn, respectively. The addition of Zn to the Mg-Al alloy system reduces the solid solubility of Al in Mg, increases the amount of precipitate phases after ageing and thus causes a moderate increase in strength. The Mg17Al12phase (γ) is reported as the precipitate formed in the Mg-Al alloys during aging after the solution heat treatment, which is the discontinuous precipitate in the grain boundary and continuous precipitate in the matrix. However, there is few report about the effect of Zn contents on age-hardening behavior and microstructure of AZ-series alloys. The propose of this study is to investigate the difference of the age-hardening behavior and microstructures of AZ-series alloys using hardness test and scanning electron microscopy (SEM) observation.
Microstructural and Mechanical Characterization of Multilayered Iron Electrodeposits
Authors: Chan C. , McCrea J.L. , Palumbo G. , Erb Uwe
Published: December 2011

Monolithic and multilayered iron electrodeposits were successfully synthesized by the pulse plating electrodeposition method. Electron microscopy and Vickers microhardness measurements were used to investigate the microstructure and mechanical properties of the iron electrodeposits produced. Two types of monolithic iron coatings were produced, one with a coarse grained, columnar structure and the other with an ultra-fine grained structure. Hall-Petch type grain size strengthening was observed in these monolithic coatings. Multilayered iron coatings composed of alternating layers of coarse grained and fine grained structures were also produced. The hardness value of the multilayered coatings falls between the hardness values for the two types of monolithic coatings produced. This study has demonstrated the possibility of applying a multilayered structure design to tailor the microstructure and mechanical properties of electrodeposited iron coatings.
Nondestructive Structure Test of Cam-Shaft Using both Eddy Current and X-Rays
Authors: Yaguchi Osama , Okada Yoshiyuki , Sasaki Toshihiko
Published: December 2011

The cam-shaft for the internal-combustion engine needs to be chilled at the foundry stage to rise the cam hardness, but unexpected chilled structures could occur on the sensor plate surface. If chilled structures exist on the sensor plate, a grinding tool may break when grinding sensor plate, or the specified shape may be unable to be produced due to resistance arising from the hyper-hardness of the chilled structures. For this reason, developing an inspection technique and a device for detecting unnecessary chilled structures before grinding the cam-shaft and for determining the rejection and removal of cam-shafts with chilled structures detected was necessary.
Effect of Different Aluminium Surface Treatments on Ice Adhesion Strength
Authors: Ghalmi Z. , Menini R. , Farzaneh M.
Published: December 2011

Excessive ice accumulation on power network equipment can affect their integrity and cause damage with serious socioeconomic consequences. To mitigate that, de-icing techniques (mechanical or thermal) have been developed, but these techniques are often limited in their application and are generally expensive and time consuming. Recently, companies and research groups have focused on the development and application of icephobic coatings such as superhydrophobic materials intended to drastically reduce ice adhesion force on exposed equipments. The aim of this paper is the examine the influence of aluminium surface treatments on ice adhesion. Preparation of new and various aluminium surface treatments as well as the need to improve the knowledge of the mechanisms involved in ice adhesion are part of this research. Depending of the type of materials, surface roughness can either promote the formation of air pockets within pores or between coating surface asperities (low adhesion strength), or it can create ice mechanical anchoring if water partially or totally penetrates the porosity. Aluminium anodization using phosphoric acid was studied. Surface morphology was evaluated using scanning electron microscopy and measurements of ice adhesion strength were performed using a centrifuge technique. Based on these results, several surface treatments of aluminium have been considered including aluminium anodizing with partial Al2O3 etching followed by different sealing steps using hydrophobic polymer compounds such as polytetrafluoroethylene.
Thermomechanical Processing of a Nb-Microalloyed Steel in a Controlled-Forging Treatment
Authors: Nakhaie Davood , Benhangi Pooya Hosseini , Mazinani Mohammad , Fazeli Fateh , Ghandehari Ferdowsi Mahmoud Reza
Published: December 2011

Ferrite grain size is one of the most important microstructural parameters in steels which can be appropriately adjusted to cause a significant strengthening effect. Thermomechanical processing is an effective method for ferrite grain refinement in microalloyed steels. Transformation of deformed austenite with a pancaked grain structure to a relatively fine ferrite phase is an important phenomenon occurring during the thermomechanical processing of microalloyed steels. The final microstructure of steels can be optimized by controlling three critical processing parameters, i.e. i) applied strain (constant strain rate), ii) deformation temperature, and iii) cooling rates following the hot deformation stage. In the present study, a new approach (called controlled-forging treatment) consisting of hot deformation of steel at the austenitic temperature range using an upset forging stage was developed for the ferrite grain refinement in a Nb-microalloyed steel. The investigated steel was subjected to a thermomechanical treatment including reheating, hot deformation for two different strain levels, namely 30 and 50% reductions of height, in a single pass hot-forging stage at temperatures below the TNR(no-recrystallization) and above the TR3(austenite to ferrite transformation) temperatures followed by cooling to room temperature using three different cooling rates. The experimental results obtained from this proposed treatment were more or less similar to those already obtained for the case of controlled-rolling process on Nb-microalloyed steel sheets.
Conventional Electrospinning vs. Emulsion Electrospinning: A Comparative Study on the Development of Nanofibrous Drug/Biomolecule Delivery Vehicles
Authors: Wang Chong , Tong Sze Nga , Tse Yuk Hang , Wang Min
Published: December 2011

Over the past decade, intensive research has been conducted on electrospinning of fibrous tissue engineering scaffolds and their applications in body tissue regeneration. For providing multifunctions and/or enhancing the biological performance, drugs or biomolecules can be incorporated in electrospun fibers using normally one of these techniques: (1) direct dissolution, (3) emulsion electrospinning, and (3) coaxial electrospinning. In this investigation, for constructing nanofibrous delivery vehicles, conventional electrospinning using polymer solutions with directly dissolved drugs or biomolecules and emulsion electrospinning were studied and compared. Bovine serum albumin (BSA) was used as a model protein and the drug was rifamycin, a hydrophobic antibiotic. A poly (lactic-co-glycolic acid) containing the protein or drug was electrospun into fibers. In these two routes of fabricating drug-or biomolecule-loaded nanofibers, different polymer concentrations and emulsion formulations were investigated. Various aspects of the fibrous delivery vehicles were investigated using several techniques and the in vitro release behaviour was studied.
On the Influence of Carbon Nanotubes and Processing on Tensile Response and Fracture Behavior of a Magnesium Alloy
Authors: Srivatsan Tirumalai S. , Godbole C. , Paramsothy Muralidharan , Gupta Manoj
Published: December 2011

Carbon nanotube (CNT) reinforced magnesium alloy (AZ31)-based composite was fabricated using the technique of solidification processing followed by hot extrusion. In this paper is presented and briefly discussed the conjoint influence of reinforcement and processing on microstructural development, microhardness, tensile deformation and final fracture behavior of the magnesium alloy composite and comparisons made with the unreinforced alloy (AZ31). The interactive influences of the CNT reinforcement and processing in governing engineering stress versus engineering strain response and tensile properties is neatly presented and discussed. The macroscopic fracture mode and intrinsic microscopic mechanisms governing quasi-static deformation and fracture behavior of both the CNT reinforced and unreinforced magnesium alloy is both elaborated and rationalized in light of the specific role played by presence of reinforcing phase in the magnesium alloy metal matrix, intrinsic microstructural effects and nature of loading.
Fabrication of Multiwalled Carbon Nanotube-Titania Nanocomposite for Dye-Sensitized Solar Cell
Authors: Lin Wei Jhih , Hsu Chun Tsung , Lai Yan Chou , Wu Wei Che , Hsieh Tsung Yi , Tsai Yu Chen
Published: December 2011

This work highlights the fabrication of multiwalled carbon nanotube (MWCNT)-TiO2 nanocomposite for use in dye-sensitized solar cells (DSSCs) to improve the photovoltaic conversion efficiency. Morphology of the MWCNT-TiO2 film was investigated by field emission scanning electron microscopy (FESEM). FESEM images demonstrated that MWCNTs were dispersed homogeneously in TiO2 matrix. MWCNT acted as an efficient conduit for electron transfer that can enhance the photovoltaic conversion efficiency of the DSSC. The proposed MWCNT-TiO2 nanocomposite photoelectrode might be beneficial to develop high photovoltaic conversion efficiency of DSSCs.
Modeling of Anisotropic Plastic Behavior of Advanced High Strength Steel Sheet TRIP 780
Authors: Panich Sansot , Uthaisangsuk Vitoon , Suranuntchai Surasak , Jirathearanat Suwat
Published: December 2011

Anisotropic plastic behavior of advanced high strength steel sheet of grade TRIP780 (Transformation Induced Plasticity) was investigated using three different yield functions, namely, the von Mises’s isotropic, Hill’s anisotropic (Hill’48), and Barlat’s anisotropic (Yld2000-2d) criterion. Uniaxial tensile and balanced biaxial test were conducted for the examined steel in order to characterize flow behavior and plastic anisotropy for different stress states. Especially, disk compression test was performed for obtaining balanced r-value. All these data were used to determine the anisotropic coefficients. As a result, yield stresses and r-values for different directions were calculated according to these yield criteria. The results were compared with experimental data. To verify the modelling accuracy, tensile tests of various notched samples were carried out and stress-strain distributions in the critical area were characterized. By this manner, the effect of stress triaxiality due to different notched shapes on the strain localization calculated by the investigated yield criteria could be studied.
The Effect of Mn Addition on the Microstructure and Mechanical Properties of Gas-Atomized Al-20Si-5Fe-3Cu-1Mg Powder
Authors: Moazzenipoor P. , Rajabi M. , Davami P.
Published: December 2011

In this study, Al-20Si-5Fe-3Cu-1Mg-XMn (X=0,1.5,3) alloys were synthesized by the gas atomizing technique. The microstructure and mechanical properties of the powders were investigated using optical microscopy, scanning electron microscopy, X-ray diffractometery method, and microhardness test. Microstructure of the powders composed of α-Al, Si and iron intermetallic compounds. As the powder particle size decreases, the phases become finer. A significant refinement in the size of iron-containing compounds was observed by addition of Mn. The microstructural refinement by controlling the particle size leads to an increase in the hardness of the powder particles in the amount of 33-45% dependent on the composition. Keywords: Al-20Si-5Fe-3Cu-1Mg alloy, Gas atomizing, microstructure, mechanical properties
Influence of Carbon Nanotubes and Processing on Cyclic Fatigue and Final Fracture Behavior of a Magnesium Alloy
Authors: Srivatsan Tirumalai S. , Godbole C. , Paramsothy Muralidharan , Gupta Manoj
Published: December 2011

Carbon nanotubes (CNT)-reinforced magnesium alloy (AZ31) was fabricated using the technique of solidification processing followed by hot extrusion. Test specimens of both the composite and the unreinforced alloy were cyclically deformed at two different load ratios spanning tension-tension loading (R = 0.1) and fully-reversed tension-compression (R= -1) loading under total stress amplitude-control. A comparison of the CNT reinforced magnesium alloy with the unreinforced counterpart revealed well over two hundred percent improvement in cyclic fatigue life at load ratio of 0.1 and about two-hundred and fifty percent improvement in the high cycle fatigue life under conditions of fully-reversed loading [R= -1.0]. At all values of maximum stress, the high cycle fatigue response of both the reinforced and unreinforced magnesium alloy was found to degrade at the lower load ratio (-1.0). The synergistic and interactive influences of reinforcement and processing on microstructural development, cyclic fatigue life and kinetics governing fracture behavior are presented and briefly discussed.
Study of B. Mori Silk Fabric and B. Mori Silk Reinforced Epoxy Composite
Authors: Chaisomkul N. , Suppakarn Nitinat , Sutapun Wimonlak
Published: December 2011

In this work, degummed(Bombyx mori)silk fabric was used as a bio-reinforcement for epoxy composite.The silk fabric was in a form of plain weaving with 177 ends/10 cm x 201 picks/10 cm. The degummed silk fabric (dSF)/epoxy composites were prepared by hand lay-up with dSF weight fraction of 0.18-0.35. The dSF was characterized using a universal testing machine (UTM) and a thermogravimetric analyzer (TGA). Mechanical properties including tensile properties, and impact property of neat epoxy and epoxy composites were investigated using a UTM and a impact testing machine, respectively. Thermal properties of neat epoxy and dSF/epoxy composites were investigated using a TGA. In addition, morphology of fracture surface of neat epoxy and dSF/epoxy composite were examined via a scanning electron microscope. Tensile strength of dSF was not significantly dependent in direction, was 537.1 N in warp direction, and 555 N in weft direction. In addition, dSF decomposed at 324°C under nitrogen atmosphere. The tensile strength and impact strength of the neat epoxy were higher than those of dSF/epoxy composites. However, tensile strength and impact strength tended to increased with increasing dSF content. On the other hand, Young’s modulus was improved by addition of dSF. The dSF/epoxy composites still fractured in a brittle manner.