bluuebunny/crossref_metadata_2025 huggingface dataset:
Probabilistic Topic Discovery and Automatic Document Tagging
Authors: Magatti Davide , Stella Fabio
Published: October 2011

A software system for topic discovery and document tagging is described. The system discovers the topics hidden in a given document collection, labels them according to user supplied taxonomy and tags new documents. It implements an information processing pipeline which consists of document preprocessing, topic extraction, automatic labeling of topics, and multi-label document classification. The preprocessing module allows importing of several kinds of documents and offers different document representations: binary, term frequency and term frequency inverse document frequency. The topic extraction module is implemented through a proprietary version of the Latent Dirichlet Allocation model. The optimal number of topics is selected through hierarchical clustering. The topic labeling module optimizes a set of similarity measures defined over the user supplied taxonomy. It is implemented through an algorithm over a topic tree. The document tagging module solves a multi-label classification problem through multi-net Naïve Bayes without the need to perform any learning tasks.
Topic Discovery in Web Collections via Graph Local Clustering
Authors: Villarreal Sara Elena Garza , Brena Ramón
Published: October 2011

An extensive review of existing literature on clustering and topic mining is given throughout the chapter as well.
Algorithms for 3D Map Segment Registration
Authors: Men Hao , Pochiraju Kishore
Published: October 2011

Many applications require dimensionally accurate and detailed maps of the environment. Mobile mapping devices with laser ranging devices can generate highly detailed and dimensionally accurate coordinate data in the form of point clouds. Point clouds represent scenes with numerous discrete coordinate samples obtained about a relative reference frame defined by the location and orientation of the sensor. Color information from the environment obtained from cameras can be mapped to the coordinates to generate color point clouds. Point clouds obtained from a single static vantage point are generally incomplete because neither coordinate nor color information exists in occluded areas. Changing the vantage point implies movement of the coordinate frame and the need for sensor position and orientation information. Merging multiple point cloud segments generated from different vantage points using features of the scene enables construction of 3D maps of large areas and filling in gaps left from occlusions. Map registration algorithms identify areas with common features in overlapping point clouds and determine optimal coordinate transformations that can register or merge one point cloud into another point cloud’s coordinate system. Algorithms can also match the attributes other than coordinates, such as optical reflection intensity and color properties, for more efficient common point identification. The extra attributes help resolve ambiguities, reduce the time, and increase precision for point cloud registration. This chapter describes a comprehensive parametric study on the performance of a specialized Iterative Closest Point (ICP) algorithm that uses color information. This Hue-assisted ICP algorithm, a variant developed by the authors, registers point clouds in a 4D (x, y, z, hue) space. A mobile robot with integrated 3D sensor generated color point cloud used for verification and performance measurement of various map registration techniques. The chapter also identifies various algorithms required to accomplish complete map generation using mobile robots.
High-Speed, High-Resolution 3D Imaging Using Projector Defocusing
Authors: Zhang Song , Gong Yuanzheng
Published: October 2011

With the advance of software and hardware, three-dimensional (3D) scene digitization becomes increasingly important. Over the years, numerous 3D imaging techniques have been developed. Among these techniques, the methods based on analyzing sinusoidal structured (fringe) patterns stand out due to their achievable speed and resolution. With the development of digital video display technologies, digital fringe projection techniques emerge as a mainstream for 3D imaging. However, developing such a system is not easy especially when an off-the-shelf projector is used. The major challenging problems are: (1) the projection system nonlinearity; (2) the precise synchronization requirement; and (3) the projection system speed limit. This chapter will present an alternative route for 3D imaging while reducing these problems. The fundamentals of the proposed technique will be introduced, the analytical and experimental results will be shown, and its advantages and limitations will be addressed.
Combining Focus Measures for Three Dimensional Shape Estimation Using Genetic Programming
Authors: Mahmood Muhammad Tariq , Choi Tae-Sun
Published: October 2011

Three-dimensional (3D) shape reconstruction is a fundamental problem in machine vision applications. Shape from focus (SFF) is one of the passive optical methods for 3D shape recovery, which uses degree of focus as a cue to estimate 3D shape. In this approach, usually a single focus measure operator is applied to measure the focus quality of each pixel in image sequence. However, the applicability of a single focus measure is limited to estimate accurately the depth map for diverse type of real objects. To address this problem, we introduce the development of optimal composite depth (OCD) function through genetic programming (GP) for accurate depth estimation. The OCD function is developed through optimally combining the primary information extracted using one (homogeneous features) or more focus measures (heterogeneous features). The genetically developed composite function is then used to compute the optimal depth map of objects. The performance of this function is investigated using both synthetic and real world image sequences. Experimental results demonstrate that the proposed estimator is more accurate than existing SFF methods. Further, it is found that heterogeneous function is more effective than homogeneous function.
“Scanning from Heating” and “Shape from Fluorescence”
Authors: Mériaudeau Fabrice , Rantoson R. , Eren G. , Sanchez-Sécades L. , Aubreton O. , Bajard A. , Fofi D. , Mohammed I. , Morel O. , Stolz C. , Truchetet F.
Published: October 2011

3D surface acquisition is a subject which has been studied to a large extent. A significant number of techniques for acquiring shape have been proposed, and a wide range of commercial solutions are available. Nevertheless, today’s systems still have difficulties when digitizing objects with non-Lambertian surfaces in the visible light spectrum, as is the case of transparent, semi-transparent or highly reflective materials (e.g. glass, crystals, some plastics and shiny metals). In this chapter, some of the issues of traditional scanning systems are addressed by considering various approaches using the radioactive properties of materials, the polarization information of the reflected light as well as the generated fluorescence applied to the digitization of transparent object These approaches led to three recent techniques which can be referred as shape from polarization, shape from fluorescence as well as shape from heating (SFH). The two latest approaches will be exposed throughout this chapter.
3D Scanner, State of the Art
Authors: Bellocchio Francesco , Ferrari Stefano
Published: October 2011

The digital models of real objects are used today in many fields: medicine, archeology, and entertainment are some examples of areas in which these models are applied. Generally, the first step of the creation of a real object’s 3D model consists in capturing the geometrical information of the physical object. Real objects can be small as coins or big as buildings: the different requirements have brought to the development of a very variegated set of techniques for the acquisition of geometrical information of the object. The aim of this chapter is to present and explain the techniques the 3D scanners are based on and compare them in terms of accuracy, speed, and applicability, in order to understand advantages and disadvantages of the different approaches.
3D Imaging for Mapping and Inspection Applications in Outdoor Environments
Authors: Sukumar Sreenivas R. , Koschan Andreas F. , Abidi Mongi A.
Published: October 2011

This chapter is aimed at introducing the fundamentals of three-dimensional (3D) imaging to scientists, students, and practitioners while also documenting recent developments in the ability to rapidly digitize real-world environments. We begin with a survey of popular 3D sensing options and list factors that challenge 3D imaging in outdoor environments. The survey guides the reader towards the choice of a 3D sensor for his or her application of interest. Then, we describe 3D data acquisition strategies and integration methodologies for multi-view range data from laser scanners, multi-view image data from cameras mounted on a mobile platform and multi-sensor localization based 3D mapping. We explain the steps involved in creating 3D models from raw sensor data for each of these data acquisition strategies. Finally, we document research results obtained in the Imaging, Robotics and Intelligent Systems Laboratory at the University of Tennessee, Knoxville from 3D imaging prototypes developed for automated pavement runway inspection and urban mapping.
3D Laser Scanner Techniques
Authors: Farjas Mercedes , Martinez-Frias Jesús , Hierro Jose María
Published: October 2011

The use of 3D scanning systems for acquiring and analyzing the external shape features of arbitrary objects has different applications in different cultural, scientific, and technological fields. In this work, 3D laser scanning techniques are used, for the first time, to our knowledge, as a novel and non-destructive application for the morphological study of meteorite impact rocks. The subject of the study was a rock displaying impact textures and associated with the Karikkoselkä impact crater (Finland) (Lehtinen et al. 1996). This methodology permitted: (1) a computerized three-dimensional modelling to be carried out on the bulk impact-related rock; (2) other more specific characterizations to be performed, such as detailed topographic studies of its surface impact features; (3) some physical properties of the rock to be determined (volume); (4) the shatter cone impact texture to be completed with a realistic estimation of its convergence angle; and (5) a broad demonstration of the significance and effectiveness of 3D laser scanning techniques as a complementary tool for the study of this type of meteoritic impact-related rocks.
Subject Independent Facial Expression Recognition from 3D Face Models using Deformation Modeling
Authors: Srivastava Ruchir , Yan Shuicheng , Sim Terence , Ranganath Surendra
Published: October 2011

Most of the works on Facial Expression Recognition (FER) have worked on 2D images or videos. However, researchers are now increasingly utilizing 3D information for FER. As a contribution, this chapter zooms in on 3D based approaches while introducing FER. Prominent works are reviewed briefly, and some of the issues involved in 3D FER are discussed along with the future research directions. In most of the FER approaches, there is a need for having a neutral (expressionless) face of the subject which might not always be practical. This chapter also presents a novel technique of feature extraction which does not require any neutral face of the test subject. A proposition has been verified experimentally that motion of a set of landmark points on the face, in exhibiting a particular facial expression, is similar in different persons. The presented approach shows promising results using Support Vector Machine (SVM) as the classifier.
Review on Method for Testing Filling Capacity of Liquid Alloys and its Application
Authors: Tang Hui Ying , Shi De Quan , Zhao Yong Jun , Li Da Yong , Shi Xu Dong , Gao Zhi Wei
Published: October 2011

In this paper, several methods for testing the filling capacity including mechanical test method, vacuum test method, electrometric method, high-speed photography method and X-ray observation method were reviewed, and they can be divided into two classes, namely traditional test method and new test method based on computer. The principles and measurement process of theses methods were summarily described. Through further analysis and comparison, their merits and limitations were indicated respectively. Also, their applications in measuring filling capacity of liquid alloys were exemplified. Finally, it is thought that the development and application of computer technology will benefit to the accuracy improvement of filling capacity.
Antibacterial Activities of Kappa-Carrageenan Oligosaccharides
Authors: Wang Fei Fei , Yao Ziang , Wu Hai Ge , Zhang Sheng Xia , Zhu Nan Nan , Gai Xue
Published: October 2011

Κ-carrageenan oligosaccharides were prepared by enzymatic degradation. The inhibiting activities of the prepared κ-carrageenan oligosaccharides against Escherichia coli (E.coli ), Staphylococcus aureus (S.aureus), Saccharomyces cerevisiae (S.cere), Penicillium citrinum (P.citr) and Mucor.sp were determined and compared by measuring the inhibitory zone diameter. The results indicate that all tested κ-carrageenan oligosaccharides have inhibiting activity against the five bacteria, but the inhibiting activities against Saccharomyces cerevisiae is higher than against any other four bacteria. The inhibiting concentration (MIC) of κ-carrageenan oligosaccharides are 1mg/ml, 5mg/ml, 20mg/ml, and antibacterial activity of κ-carrageenan oligosaccharides was inversely affected by concentration, with the highest activity at the concentration of 5mg/ml.
An Acetic-Acid Type Climax Community and its Changes Aroused by COD/SO42- Ratio in an Acidogenic Sulfate-Reducing Reactor
Authors: Bao Hong Xu , Ma Xi Ping , Wang Jian , Jing Kui , Chen Zhi Hui , Wang Ai Jie
Published: October 2011

The objective of this study is to investigate the microbial community and its characteristics changes aroused by the ratios of COD/SO42- in the acidogenic-phase reactor of two-phase anaerobic process. A continuous-flow lab-scale test was conducted in an acidogenic sulfate-reducing reactor with molasses wastewater as sole organic carbon source and sodium sulfate as the electron acceptor. The experimental results showed that Acetic-acid Type Microbial Metabolism resulted in the formation of An Acetic-acid Type Climax Community. The change of the COD/SO42- ratio caused an ecological succession from a stable climax community at moderate and high COD/SO42- ratios to a sub-stable climax community at a lower COD/SO42- ratio. But Acetic-acid Type Microbial Metabolism kept unchanged during this course, which indicated the stability of Acetic-acid Type Climax Community. The Acetic-acid Type Microbial Metabolism and Acetic-acid Type Climax Community were of typical characteristics in the acidogenic sulfate-reducing reactor.
Research on Simulation and Optimization of Facility Layout in Flexible Manufacturing Workshop
Authors: Huang Dong Mei , Zhang Guo Jun , Shi Song Xin
Published: October 2011

The Facility layout of flexible manufacturing workshop is designed under process principle, which is suitable for medium and small batch production．However, large WIP is produced under this facility layout model, and the material transport is relatively disorderly, the production cost is caused very high. Aiming on the problem, the facility layout with variety of materials is researched, and the mathematical model of lowest logistics cost is established with the total logistics cost as the objective function. Finally, according to the workshop equipment layout optimization process, the simulation mode in unit is established with the computer simulation software eM-Plant, and the logistics cost is optimized and compared with the initial result.
Effects of Gibberellins Treatment on Storage Quality and Nutrition Components of Loquat
Authors: Bai Wei Dong , Zhao Wen Hong , Lu Zhou Min , Cao Xue Dan , Zhang Zhong Liang
Published: October 2011

In order to study the effects of Gibberellins (GA3) treatment on fresh-keeping effect and storage quality, provide theoretical foundation for loquat production, the loquat fruit grown in Guangdong Province were separated in groups and dipped in different concentrations (10, 50, 100 μmol/L) of GA3 solution respectively for 20 min, and then stored at a chamber with temperature of 3±0.5°C, relative humidity of 65~80%. The rotten index, flesh hardness, weight-loss ratio, contents of total soluble solids, soluble sugar, titrable acidity and vitamin C were measured periodically. The results show that by GA3 treatment ,the rotten index and flesh firmness of loquat fruit decrease significantly, and storage time of loquat lengthen effectively. It also indicate the content of titrable acidity can be greatly reserved to some extent by 10 μmol/L GA3 treatment, and the loss of vitamin C content drop highly, generating better flavor and quality of loquat fruit.
Transcriptional Distribution in Various Organs and Transcriptional Response to Abiotic Stress for Trehalose Metabolism Genes in Arabidopsis Thaliana
Authors: Song Yan Zhai , Liu Shuang , Wen Mei , Huang Wei , Song Xiang Li , Guo Bei
Published: October 2011

Trehalose (α-D-glucopyranosyl-1,1-α-D-glucopyranoside) is a non-reducing disaccharide. It is currently thought that just trace level of trehalose was detected in plants, and that trehalose metabolic pathway was significantly related to stress tolerance. In this study, we report that expression levels of three genes with regard to trehalose metabolic pathway were measured in Arabidopsis thaliana, including AtTPS1, AtTPPA and AtTRE1. As a result, transcriptional levels of these genes are the highest in floral organ, and the expression of AtTRE1 is much more than AtTPS1 and AtTPPA. Additionally, we present transcriptional response analyses in drought and heat stresses, which have shown the changes of these genes expression from tolerance in early stress to senescence in later stress.
Deriving Plastic Constitutive Equations of the Material in Complex Stress State by Means of Simple Test Results
Authors: Feng Xiao Jiu , Liang Li Fu
Published: October 2011

By conducting simple tension and torsion tests to material, constitutive equations of one dimension are obtained. Plastic theories of continuum mechanics are used for analyzing deformation behavior of the material after yielding. Here, material is presumed to have isotropic hardening characteristic. By using Mises loading function and the associative flow rule, the derivations are made to extend the constitutive equations of one dimension in the simple tension and torsion tests to that of multi-dimension and obtain the plastic constitutive equations of the material in complex stress state , respectively.
Crack Behavior of Fe-Based Coating by Plasma Cladding
Authors: Liu Jun Bo , Wang Li Mei , Huang Bao Xin
Published: October 2011

On the base of orthogonal comparison tests, influences of many kinds of factors on plasma cladding crack sensibility were studied. The results indicate that substrate and its surface state, processing parameter and components of plasma cladding coating have great effects on crack sensibility of plasma cladding coating. Through changing these factors, it is possible to reduce cracks and expand ranges of applications of this technology.
Study on Emission Control of CNG Engine Based on D-S Evidence Theory
Authors: Li Xi Qin , Cai Su Yan , Liu Bing , He Xue Qun
Published: October 2011

To reduce emissions, CNG engines are commonly equipped with three-way catalytic converters. However when the engines run at transient conditions, the air fuel ratio can not be precisely controlled at theoretical value by traditional means, so the catalytic converters can not achieve their desired effect. This paper presents a new method for CNG engines to control air fuel ratio at transient conditions. The moments which intake and exhaust valves open are used as the trigger signals for ECU to collect the test data simultaneously. The dynamic information of CNG engine is detected by multiple sensors; the nonlinear coupling relationship between air fuel ratio of CNG engine and the operating conditions are established through information fusion and neural network control. The requirement of real time control for air fuel ratio is achieved, so the emissions of CNG engines are reduced further.
Generic Object Detection Based on Boosting Embedded with Bag-of-Words
Authors: Qiu Xue Na , Liu Shi Rong , Song Jia Tao
Published: October 2011

This paper studies generic object detection. In the view of complexity and diversity of generic object, it proposes Boosting generic object detection method with bag-of-words. Boosting method has good detection efficiency, but it has some fault detections due to the diversity and complexity of the object. While Bag-of-words method has some advantages, such as local patch features, simplicity and robustness, and it has good classification performance of complex object. The proposed method applies Bag-of-words to remove the fault detection and to improve the tracking results of Boosting, and thus it achieves high generic object detection accuracy.
A Novel Fault Diagnosis for Rolling Element Bearings Based on Continuous Wavelet Transform and Hidden Markov Model
Authors: Zhang Rui Ge , Tan Yong Hong
Published: October 2011

This paper presents a novel approach to detect the fault categories for rolling element bearings based on the continuous wavelet transform and hidden Markov models. With the Morlet wavelet transform, the effective fault information is extracted from the time-frequency domain of the vibration signals. Then, the wavelet coefficients are divided into multi-segments, and the infinity-norms of each segment is applied as the features to construct the observation vector of the hidden Markov models. Finally, the experimental results on bearing faults identification and isolation are illustrated.
Research on the Integrated Development System of NGW Planetary Gear Transmission
Authors: Wu Jing Bing , Shu Lun , Wang Xie
Published: October 2011

Using VB, Matlab and 3D CAD software Solidworks to develop integration development system of NGW planetary gear transmission. There are two big function modules in this system, optimal design and parametric modeling. By Using the hybrid programming method of VB and Matlab , permeated the optimal design into the process of design, realized optimimal calculation of the main parameters of gear parts; and the automation of 3d modeling realized by using VB, The second time developing tool of Solidworks. Which Greatly increase the R&d efficiency of product and the market competitiveness of enterprises.
Studies on Mega-Pixel Cell Phone Lenses Based on Aspheric Optics
Authors: Zhu Yong Jian , Chen Feng Jun , Yin Shao Hui
Published: October 2011

According to the principle of optical design, two kinds of 2 Mega-pixel cell phone camera lenses are proposed. One is made up of three plastic (3P) lenses; the other is made up of two plastic lenses and one glass (2P1G) lens. The shapes of all lenses are aspheric. By comparison, the overall length of 2P1G lens is much less than that of 3P lens. Furthermore, in FOV the former is 5 degrees larger than the latter. At the same time, in distortion of the maximum field angle, the former is much less. The other aberrations of 2P1G lens are almost same to those of 3P lens. Therefore, in cell phone camera lens design, it’s recommended to adopt one aspheric glass lens to improve the performance and compactness though the cost will become a little higher due to the introduction of aspheric glass lens. However, the cost of aspheric glass lens could be reduced tremendously by a new cost-effective manufacturing method  compression molding technology.
Study on the Performances and Interfacial Structure of Magnesium Hydroxide Whiskers/ABS Composites
Authors: Jiang Yu Zhi , Zhang Li Li , Li Yan Bo
Published: October 2011

The magnesium hydroxide (MH) whiskers / ABS composites were prepared by melt-extrusion with modified whiskers as filler. The mechanical performances, including the tensile strength, elongation at break and elastic modulus, were tested by electronic universal testing machine. The results showed that with the increasing of the whisker dosage, the tensile strength and elongation at break reduced gradually, and the elastic modulus get maximum when it is 25%.The morphology on fracture of composites was analyzed by SEM. The conclusions are the whiskers of surface modifications can be evenly distributed in the composites and bond partly with ABS. that it is necessary to enhance the combine strength of interface on excellence performances of composites.
A Time Petri Net Representation for Scientific Research Project Management
Authors: Ren Bing Qun , Guo Jun , Zhong Wei Zhou
Published: October 2011

An efficient and convenience model of business process plays a crucial role in scientific project management. Existing Petri net models lack the ability to cope with the time constrain of the business process. Thus the time factor was introduced to Petri net in this paper. The formal definitions of time Petri net were presented in details. The techniques to model the business process of scientific project management system with the time Petri net were discussed as well. A time Petri net model for an instance of scientific project management system was setup and study. The research results indicate the time Petri net is an efficient method to represent the scientific project management system.
A New Efficient Secure Multi-Party Computation
Authors: Tang Yong Long
Published: October 2011

In an existed multi-party computation protocol, any verifier must be a participant. A new secure multi-party computation among t participants and a verifier was proposed, in which the verifier no belong to participants can learn the final output. Our protocol is more practicable in some important situations, for example, in an electronic bidding, where an arbiter is only a verifier but is usually not a participant.
Optimization Methods of Loading Path for Tube Hydroforming
Authors: Tao Zhi Hua , Yang Lian Fa , Mao Xian Chang
Published: October 2011

Tube hydroforming (THF) is an efficient and economical technology of tube cool-plastic forming process. Loading path is one of the most efficacious factors which affect the THF process and quality of hydroforming parts. The forming failures, such as bursting, buckling and wrinkling, can be avoided by using suitable loading path in the THF process. Furthermore, an optimal loading path is beneficial to improve the uniformity of wall thickness and formability of material. In this paper, the importance of loading path to THF process is briefly discussed; typical optimization methods of loading path are enumerated and classified; characteristics and insufficiencies of these methods are pointed out. Main problems and trends of development in optimization methods are summarized.
Improve Lower Leg Impact Performance Considering Pedestrian Protection
Authors: Chen Jin Hua , Huang Xiang Dong
Published: October 2011

To improve the lower leg impact performance of the vehicle bumper in the collision of vehicle to pedestrian, the finite element (FE) model of a vehicle front structure was developed, and correlated with the test results. The lower legform impactor FE model was used to investigate the performance of the vehicle bumper at different structure conditions. It was finally determined that vehicle to lower legform impact performance can be improved by reducing the energy absorbing foam stiffness and modifying the bumper bracket structure to enlarge the collapse space.
Effect of Synthesis Condition on the Solubility of Surface-Modified Calcium Borate Nanoparticles
Authors: Xu Xiao Hong , Xue Qun Ji , Li Jiu Sheng , Hao Li Feng
Published: October 2011

To find a kind nanoparticles can be used as additive in lubricants, oil-soluble calcium borate nanoparticles were prepared in the present of Na2B4O7.10H2O, CaCl2, and oleic acid as modifier by in-situ method, and the effects of different reaction conditions on the coil-solubility of the nanoparticles were investigated. The results indicate that the surface of calcium borate was altered from hydrophilicity to hydrophobicity after the modification with oleic acid, and so the nanoparticles possess high solubility in mineral base oils. Moreover, TT-IR confirms that the bond of oleic acid onto the surface of calcium borate nanoparticles exists.
First Principles Study on the TiN/BN/TiN Interface
Authors: Wang Bao Jun , Xie Fei , Jia Ke Jun
Published: October 2011

To obtain a understanding of the deform mechanism and ideal strength in superhard nanocomposites nc-TiN/a-BN. we studied, using the first-principles calculation method, the geometrical stucture, the electronic density and the tensile stress-strain response of a theoretical interfacial system TiN/BN/TiN, which consists of two TiN slabs and one sandwiched BN monolayer. The calculated results show that Friedel oscillations weaken the Ti-N interplanar bonds next to the interface, where decohesion happens. A comparison with the TiN/SiN/TiN interface was done, showing that the orientation has the huger influence on the tensile strength of TiN/BN/TiN interface.
Determining New Baselines of Wear Material in Diesel Engines, Using Oil Analysis Results
Authors: Sayyah Ali , Sayyah Moones , Ramezani Saeed
Published: October 2011

Oil analysis technique is used as predictive and proactive tools to identify the wear modes of rubbing parts and to diagnose the faults in machinery. In this paper, the wear behavior of diesel engines, especially on oil analysis, is studied based on condition data. In terms of analyzing historical data, descriptive statistics is used as data mining tools to find the relationship between condition factors of the machine and its final status. The equipments have been monitored in two different environments which are: plantation-forestry, and general construction. Based on this relationship a specific baseline is achieved for selected sets of equipment in their specific conditions. A striking result is that the new baseline for each material is different significantly in each condition, which shows that for each condition making a specific baseline is essential.
A Computational Investigation of Thermal Effects on Resin Coating Flows in an Optical Fiber Drawing System
Authors: Kim Kyoung Jin , Kwak Ho Sang , Choi Jin Su
Published: October 2011

In manufacturing optical fibers, there has been intense research efforts of continually increasing fiber drawing speed to improve productivity. However, higher speed fiber drawing poses new challenge in many areas of optical fiber manufacturing. In this paper, thermal effects on coating resin flow in an unpressurized coating applicator are studied numerically. Present simulation results found that higher fiber drawing speed leads to severe viscous heating in coating resin flow and significant increase of resin temperature, which in turn leads to substantial viscosity decrease. These thermal effects profoundly alter the resin flow patterns and velocity profiles in the coating die and they should be considered in controlling the final coating thickness.
Research and Analysis of a Laser-Type High Temperature Pressure Sensor Based on SiC Diaphragm
Authors: Hu Yan Qing , Hu Guo Qing , Yi Shao Xiang , Zhang Jian Wei
Published: October 2011

In the field of high temperature sensing applications, Silicon carbide (SiC) is a superior material due to its excellent mechanical, thermal and chemical properties. Laser triangulation is a technology of non-contact, rapidity, and high accuracy. Its characteristic of non-contact can realize the high temperature non-resistance components’ isolation from the high temperature components of the sensor effectively, so as to achieve measurement under high temperature. Meanwhile, its measurement accuracy can be further improved effectively by using the principle of lens imaging of magnification and constant focus, combining with the high-resolution photodetector. This paper first applied it to the measurement of pressure under high temperature, and proposed a laser-type high temperature pressure sensor using SiC diaphragm as the pressure-sensitive diaphragm. The sensor measured the center deflection of the circular SiC diaphragm caused by pressure and temperature using the laser triangulation, then created the corresponding relationship between the pressure, temperature and deflection according to the thermoelasticity theory. The paper first established the mathematical model of the high accuracy laser triangulation. Afterward did the thermomechanical finite element analysis of the SiC diaphragm using ANSYS. The research and analysis demonstrate that this technical scheme of measurement of pressure under high temperature is effective and feasible, and provide a forceful and important basis for the design and realization of the sensor.
Experimental Study of Relationship between Wave Interfacial Instabilities and Mechanical Strength of Three-Layer Polymer Structure
Authors: Ranjbaran Mohammad M.
Published: October 2011

In this research, an experimental apparatus has been developed for observing interfacial stability and deformation of multilayer pressure driven channel flows. The interface instability of the co-extrusion flow of polyethylene and polypropylene is studied experimentally in a slit geometry. This is done by introducing disturbances of controlled wave length and amplitude on three-layer symmetric (A-B-A) polymer melts as well as performing a series of extrudate mechanical testing. In this study variations of the mechanical properties as well as wave interlocking have been related to the conformation of the interfacial waves (IW). By investigating the growing (IW) and tensile stress of extrudate samples a relationship between interfacial instability (II) and mechanical properties of polypropylene (PP) and high density polyethylene (HDPE) has been established. It has been shown that instabilities are associated with IW, and it turns out that IW amplitude is known as a mechanism for controlling the strength of three layer polymer products. It is shown that the mechanism of interfacial strength is related to interfacial instabilities as well as the interfacial strength. By considering that the instability is controlled by its dominant mode. It is shown that there is ability to forecast the quality of final products in co-extrusion process.
Computer Simulations of Galvanic Corrosion Behaviour of Zinc –Aluminium Based Composites Reinforced with Red Mud by Potentiodynamic Polarization Techniques Leading to Corrosion Control
Authors: Jayaprakash H.V. , Veeraiah M.K. , Krupakara P.V. , Gireesha C.
Published: October 2011

The present investigation aims to evaluate the corrosion control properties of metal matrix composites in comparison with matrix alloy using different concentration of Sodium chloride solutions and potentiodynamic polarization techniques. Matrix alloy used in ZA-27 and the reinforcement used was red mud particulates of size 50-80 microns. Composites are prepared by liquid melt metallurgy technique using vortex method. Red mud particulates reinforced varying from two to six percent by weight in steps of two percent under dry conditions. Specimens are prepared according to ASTM standards. Both composites and corresponding base alloys were subjected to identical test conditions to understand the influence of the reinforcement on alloy corrosion behaviour and effective corrosion control. Composites became less prone to corrosion and pit formation than the matrix alloy, which may be due to chemically inert red mud particles present in the metal matrix composites. On the other hand the test also reveals that corrosion resistance of both alloy and composites in crease with increase in normality of the sodium chloride solution, which may be due to increasing concentration of hydrogen ions in the solution. Corrosion of alloys can be effectively controlled by converting them in to composites by the addition of inert materials like silica particulates. If any automobile parts like bearing are made using these composites corrosion control properties can be tailored so that they can be used effectively in wide area of application.
Fatigue Life Assessment of Fastened Composite (FRP and CRP) Plates: A Comparative Study
Authors: Pandey K.N. , Tembhurne Yogesh K.
Published: October 2011

Composite materials are now a day most frequently used materials in aerospace structures. Mechanically fastened joints are usually used there for joining process due to number of advantages over other conventional joints. These joints are easy to assemble and dissemble and are cheaper. However, they create stress concentration near the hole, leading to source of nucleation and subsequent propagation of cracks under cyclic loading. They also increase weight of the system tat may nullify the advantages we get from composite materials. The present work intent to find fatigue life of two composite laminates usually employed in spacecraft structures. The composites studies are fiberglass reinforced Plastic (FRP) and Carbon Reinforced Plastic (CRP). After preparing the composites, moisture, tension and fatigue tests were conducted on both composites. To know the behavior under damped condition, absorption tests were conducted. Fatigue tests were done both under as plate and butt joint conditions. It was found that in bolted joint condition, both CRP and FRP plates fails in net tension at minimum load but for maximum load they fail in shear.
Computational Investigation of Delamination in HAT-Section Laminated Composite Components
Authors: Soltani Hamid , Shakib S.M.Mohseni , Asadi M. , Ramezani M.K.
Published: October 2011

This paper aims at developing the numerical of delamination in laminated composite structures. Formation of initial delamination and growth of existing delamination in HAT-Section laminated made of plies of unidirectional carbon fiber reinforced epoxy resin is investigated computationally. Tsai-Hill failure method is employed to predict delamination initiation while delamination propagation is analyzed using linear elastic fracture mechanics (LEFM).The techniques based on LEFM that have been utilized successfully within the framework of the finite element method (FEM) for the simulation of delamination growth, the virtual crack closer technique (VCCT). Finally this paper proposes future work for precise prediction of delamination of unidirectional carbon fiber reinforced epoxy resin HAT-Section specimens.
Synthesis and Enhanced Proton Conduction in a 20 mol% Ytterbium Doped Barium Zirconate Ceramic Using Zn as Sintering Aid
Authors: Rahman Seikh M.H. , Ahmed Istaq , Eriksson Sten G.
Published: October 2011

20% Ytterbium (III)-doped perovskite structured barium zirconate, BaZrO3, was prepared by two different synthesis routes: solid state and sol-gel routes. 2 % Zinc (II) was added as an acceptor dopant at the Zr (IV) site according to stoichiometry. It was also added as 2 % excess of the formula. The purpose of this study is to see how zinc (II) acts as a sintering aid in view of synthesis route, densification and conductivity of the material. A dense ceramic (90% of theoretical density) was achieved by the sol-gel method when stoichiometry was adjusted. Phase purity of the samples was checked by X-ray powder diffraction (XRD). Thermogravimetric analysis (TGA) and Impedance spectroscopy (IS) was used to characterize hydration and electrical conductivity respectively.The data shows that the addition of stoichiometric amounts of Zn2+ via sol-gel synthesis route promotes not only densification but also water incorporation and conductivity in comparison with the solid state route, keeping the same final sintering temperature of 1500°C. For example, pre-hydrated BaZr0.78Zn0.02Yb0.2O3-δ, prepared via the sol-gel method shows total conductivity (σtot) value of 3.14*10-5 and 3.8*10-3Scm-1, whereas for the solid state route, σtot values are 1.74*10-5 and 8.87*10-4Scm-1 under dry Ar (heating cycle) at 300° C and 600° C, respectively.
Bending Analysis of Composite Sandwich Plates with Flexible Core Using 3D Finite Element Method
Authors: Kheirikhah Mohammad Mahdi , Khalili Seyyed Mohammad Reza
Published: October 2011

Sandwich plates have been extensively used in many engineering applications such as automotive and aerospace. In the present paper, an accurate finite element model is presented for bending analysis of soft-core rectangular sandwich plates. The sandwich plate is composed of three layers: top and bottom skins and core layer. The core is assumed as a soft orthotropic material and skins are assumed generally unequal laminated composites. Finite element model of the problem has been constructed in the ANSYS 11.0 standard code area. Continuity conditions of transverse shear stresses at the interfaces are satisfied as well as the conditions of zero transverse shear stresses on the upper and lower surfaces of plate. Also transverse flexibility and transverse normal strain and stress of core are considered. The effect of geometrical parameters of the sandwich plate are studied. Comparison of the present results with those of plate theories confirms the accuracy of the proposed model.
The Effect of Nanotube Specifications on Multi-Scale Modeling of Nanocomposites
Authors: Khalili Seyyed Mohammad Reza , Haghbin A.
Published: October 2011

The effect of diameter, chirality and volume fraction of SWCNTs on the tensile behavior of nanocomposites is studied. Multi-scale material modeling is applied to assemble different RVEs composed of various SWCNTs embedded in polymer. Nanotubes are modeled in continuum mechanics, based on their atomic structures as space frame structures. Beam elements in this structure are defined based on carbon bonds characteristics in molecular mechanics. Polymer portion of the RVE is modeled as a linear elastic continuum material, with lower accuracy regarding to the multi-scale modeling technique. Attained stress-strain curves obtained from modeled nanocomposites revealed that using Armchair SWCNTs in RVEs makes nanocomposites tougher rather than Zigzags. Also, diameter of CNT has an inverse effect on the curves level. Moreover, the effect of diameter is more obvious at higher volume fraction of CNTs.
Simulation BeSe Nanowires in Two Phasese Zinc-Blende and Wurtzite Using Density Functional Theory
Authors: Alimohammadi Mina , Mokhtari Ali
Published: October 2011

In this work, we are reporting on the simulation of the beryllium selenide (BeSe) nanowires (NWs) by computational package Q-Espresso / PWSCF according to the ab-initio calculations. Structural and electronic properties, including cohesive energy and Density Of State (DOS) BeSe NWs in two phases on the zinc–blende (ZB) and wurtzite (WZ), using density functional theory based on pseudo-potential approximation and generalized gradient approximation (GGA) up to 20 angstrom in diameter has been calculated. Due to dangling bonds (DBs) in the side surface NWs, cohesive energy is obtained less than the amount of this energy in bulk state of this compound, but with increasing diameter of NWs, the amount of this energy will approach to the bulk state. Comparison of cohesive energy with beryllium selenide NWs in two phases, we find these NWs in WZ phase is more stable and have good compatibility for this result with other results in NWs of similar compounds. The value of energy gap in these NWs on various diameters is obtained less than the amount of the bulk state. It is observed that by increasing the diameter of NWs, the cohesive energy approaches to its value in bulk state.
Effect of Quenching Media and Ageing Time on Al6061-Beryl Composites
Authors: Reddappa H.N. , Niranjan H.B. , Suresh K.R. , Satyanarayana Kestur Gundappa
Published: October 2011

— Aluminum alloy based metal matrix composites are becoming very popular because of their outstanding properties such as high strength to weight ratio, excellent mechanical properties and improved wear properties. From literature survey it was observed that very limited report available on Aluminum alloy-beryl composites, particularly on the effect of beryl content, quenching media and heat treatment on the mechanical and wear properties of Aluminum-beryl composites. Accordingly, the aims of the present study are (i) preparation of Al6061-beryl particles by liquid metallurgy method (stir cast) with possible standardization of the beryl addition to liquid Aluminum alloy, (ii) Study the effect of different quenching media and the beryl content (2-12 wt. %) on the mechanical and wear properties of these composites in both as cast and heat treated conditions. Heat treatment procedure of solutionising at temperature of 5300C for 1hour and quenching in different media (air, water and ice) followed by natural and artificial ageing for different times was adopted. It was observed that the addition of beryl particles to Al6061 alloy improves its hardness, tensile strength and wear resistance with increasing beryl content while the heat treatment had significantly improved these properties compared to that of base alloy and as cast composites.
Investigation into the Electromagnetic Interference Shielding Effectiveness of Silicon Rubber Filled with Carbon Fiber
Authors: Hu Yong Jun , Zhang Hai Yan , Xiao Xiao Ting , Li Feng , Cheng Xiao Ling , Hu Guang Hui
Published: October 2011

In this paper, the silicone rubber composed of carbon fibers was prepared. The influence of different concentration of carbon fibers on the conductivity, electromagnetic shielding interference effectiveness property of the silicone rubber was discussed from the point of view of condition of carbon fiber and silicone rubber. The results showed that there existed the extreme conductivity and shielding effectiveness (SE) across the tested frequency range from 2.6 GHz to 3.95 GHz of silicone rubber composites filled with carbon fibers. When the content of the carbon fibbers was 50 parts per hundred of rubber (phr), the SE values of composites were typically above 63 dB and close to the extremum. The compact packing structure of carbon fibers does not play an important role in improved the conductivity of composite. The SE of the composite depends on the conductivity of composite.
The Effect of Preheated Crude Palm Oil on Performance and Emission Characteristics of a Compression Ignition Engine
Authors: Deepanraj B. , Raman L. Anantha , Santhoshkumar A. , Santhanakrishnan S.
Published: October 2011

Fossil fuel resources are decreasing daily and attracted researchers to focus on alternative fuels. Biofuels (renewable fuels) are attracting attention worldwide as blending components or direct replacements for petroleum based fuel in vehicle engines. Moreover, Biofuel will also provide rich biomass and nutrients to the soil. This paper presents the results of performance and emission analysis carried out in a naturally aspirated unmodified diesel engine fuelled with preheated crude palm oil (PCPO) and its blends with diesel. It was observed that preheated CPO reduces exhaust emissions such as CO and HC as compared to ordinary diesel (OD). This is mainly attributed to the fact that preheating of crude palm oil reduces its viscosity to the level of ordinary diesel fuel, which improves the fuel spray and atomization characteristics and produces better combustion.