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Generalized thermoelastic functionally graded spherically isotropic solid containing a spherical cavity under thermal shock

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Applied Mathematics and Mechanics(English Edition) 2008年第10期29卷 1263-1278页

作者： M.k.Ghosh M.kanoria Department of Mathematics Serampore CollegeSeramporeHooghly-712201India Department of Applied Mathematics University of Calcutta 92 A.P.C.RoadKolkata-700009India

This paper is concerned with the determination of thermoelastic displacement, stress and temperature in a functionally graded spherically isotropic infinite elastic medium having a spherical cavity, in the context of the linear theory of generalized thermoelasticity with two relaxation time parameters （Green and Lindsay theory）. The surface of cavity is stress-free and is subjected to a time-dependent thermal shock. The basic equations have been written in the form of a vector-matrix differential equation in the Laplace transform domain, which is then solved by an eigenvalue approach. Numerical inversion of the transforms is carried out using the Bellman method. Displacement, stress and temperature are computed and presented graphically. It is found that variation in the thermo-physical properties of a material strongly influences the response to loading. A comparative study with a corresponding homogeneous material is also made.

关键词： generalized thermoelasticity functionally graded material (FGM) Green-Lindsay theory vector-matrix differential equation Bellman method

Seismic behavior of concrete filled steel tubular arch structures

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Earthquake Engineering and Engineering Vibration 2005年第1期4卷 107-115页

作者：熊峰 Sashi k kunnath 刘浩吾 Dept. of Civil Engineering Sichuan University Chengdu 610065 ChinaProfessor Dept. of Civil and Environmental Engineering California University at Davis CA95616 USAProfessor Dept. of hydraulic Engineering Sichuan University Chengdu 610065 ChinaProfessor

Shaking table tests of a 1:10 scale arch model performed to investigate the seismic behavior and resistance of concrete filled steel tubular (CFT) arch structures are described in this paper. The El-Centro record and Shanghai artificial wave were adopted as the input excitation. The entire test process can be divided into three stages depending on the lateral brace configurations, i.e., fully (five) braced, two braces removed, and all braces removed. A total of 46 tests, starting from the elastic state to failure condition, have been conducted. The natural vibration frequencies, responses of acceleration, displacement and strain were measured. From the test results, it is demonstrated that the CFT arch structures are capable of resisting severe ground motions and that CFT arches offer a credible alternative to reinforced concrete arches, especially in regions of high seismic intensity.

关键词： concrete filled steel tube arch structures shaking table test seismic behavior lateral braces

Genotoxic Effects of PAH Containing Sludge Extracts in Chinese Hamster Ovary Cell Cultures

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Biomedical and Environmental Sciences 2003年第1期16卷 68-82页

作者： k.krISHNamUrTHI FONTDEVI T.CHAkrABArTI Environmental Biotechnology Division National Environmental Engineering Research InstituteNehru MargNagpur-440020IndiaEnvironmental Biotechnology DivisionNational Environmental Engineering Research InstituteNehru MargNagpur-440020IndiaEnvironmental Biotechnology DivisionNational Environmental Engineering Research InstituteNehru MargNagpur-440020India

Objective Many studies have been conducted in order to evaluate the genotoxicity of chemicals and waste materials, which utilized in vivo test protocols. The use of animals for routine toxicity testing is now questioned by a growing segment of society. Methods keeping the above fact in mind, we have conducted in the present study the genotoxicity evaluation of oily sludge samples generated from a petroleum refinery and petrochemical industry and ETP sludge from petroleum refinery using DNA damage, chromosomal aberration, p53 protein induction and apoptosis in short term in vitro mammalian Chinese Hamster Ovary cell cultures. results It is evident from the results that the oily sludge compounds derived from petroleum refinery and petrochemical industry could cause DNA damage, chromosomal aberration, p53 protein accumulation and apoptotic cell death on exposure to oily sludge extracts in the presence of metabolic activation system (S-9 mix), however, ETP sludge extract could not cause significant genotoxicity in comparison to oily sludge extract and negative control. Conclusion The effect may be attributed to polycyclic aromatic hydrocarbons present in the samples as evidenced from GC-MS.

关键词： DNA damage Chromosomal aberration p53 protein induction Apoptosis Genotoxicity Polycyclic aromatic hydrocarbons (PAHs) Gas chromatograph mass spectrometer (GC-MS)

Properties of Cast Hiduminium/Corundum Particulate Composites

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Journal of Materials Science & Technology 1995年第3期11卷 171-175页

作者： k.H. W. Seah(Dept. of Mechanical Engineering, National University of Singapore, 10 kent ridge Crescent, Singapore 0511)r.S.kulk.r. and S.C.Sharma (Dept. of Mechanical Engineering, r.V.College of Engineering, Mysore road, Bangalore-560-059, k.r.ataka, Ind National Univ of Singapore Singapore Singapore

This paper reports some results obtained in an investigation to see how increasing the corundum dispersoid content from o% to 7% in a matrix of hiduminium alloy affects the tensile and compressive strengths, the hardness and the casting characteristics of the composite. The results show that as the corundum content is increased, ultimate tensile strength (UTS)- compressive strength and hardness increase remarkably, whereas fluidity of the molten composite during casting drops significantly. It was found that just a minute amount of corundum is sufficient to cause a fairly large change in the mechanical properties and the fluidity of the molten *** drop in castability is one of the reasons why adding corundum beyond 7 percent is not recommended. If other factors are kept constant, the fluidity is seen to slightly improve if the pouring temperature of the molten metal were increased from 670 to 710℃

关键词： Cast Properties of Cast Hiduminium/Corundum Particulate Composites ASM

Micro-Structure, Ac Conductivity and Spectroscopic Studies of Cupric Sulphate Doped PVA/PVP Polymer Composites

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Advances in Materials Physics and Chemistry 2015年第10期5卷 408-418页

作者： k. Hemalatha H. Somashek.r.ppa r. Somashekar Department of Physics Yuvaraja’s College University of Mysore Mysore India Department of Studies in Material Sciences University of Mysore Mysore India

A series of polyvinyl alcohol/polyvinyl pyrrolidone polymer composite films doped with different amount of cupric sulphate (CuSO4) were prepared by means of solution casting technique. These films were characterized by X-ray diffraction (XrD), Fourier transform infrared spectroscopy (FT-Ir), Ultraviolet-Visible absorbance spectroscopy (UV-Vis) and Ac conductivity measurement studies. XrD patterns of these films recorded at room temperature show the increase in amorphousity of the matrix with the increase in the concentration of CuSO4 in polymer composites. Microstructural parameters were computed using an in-house program employing XrD data. recorded FT-Ir spectra give information about the stretching and bending of the characteristic absorption bands in these films. The variation in the transmittance has been studied with the help of recorded UV-Vis spectra and hence the optical band gap present in the samples is also calculated. The measured Ac conductivity shows how the conductivity varies in these films with the presence of different amount of CuSO4 in these films.

关键词： Crystallanity X-ray Diffraction amorphous Microstructural Parameters Ac Conductivity

Alpine Taxa Exhibit Differing responses to Climate Warming in the Snowy Mountains of Australia

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Journal of Mountain Science 2010年第2期7卷 167-175页

作者： k.GrEEN National Parks and Wildlife Service Snowy Mountains RegionPO Box 2228Jindabyne NSW 2627Australia

The phenologies of plants and animals in snow-covered landscapes are expected to accelerate with global ***,there are few studies that have examined a range of unrelated taxa in alpine environments to determine whether there is commonality in the proximate causes,synchrony in timing,or the direction of any *** for five alpine animal species and two alpine plant species,chosen primarily for their visibility,were examined to determine their temporal response to regional climate *** the 30-year period studied,they showed an array of different phenological *** flowering appeared linked to date of snow melt,whereas animal responses *** having accelerated phenologies,two migratory bird species exhibited contrary changes;one to low-altitude warming regardless of snow conditions in the alpine zone (flame robin) and the other to state of the snowpack.r.gardless of low-altitude temperatures (richard's pipit).By contrast,the migratory bogong moth arrived significantly later over the years with no apparent explanatory climatic *** bogong moths are not responding to earlier snow melt,insectivorous predators on the ground *** could lead to a serious mismatch in timing at different trophic levels,putting pressure on endangered *** of locally wintering insect species,March flies and Macleay's swallowtails,were not significantly related to measured climatic parameters over the study period.A consequence of the disparate responses to climate warming recorded here is the questionable value of 'indicator species' to examine the impact of climate warming on alpine ecosystems.

关键词： Bogong moth Climate change Migration Mismatch Phenology

Development of the Documentation and Appraisal review Tool for systematic reviews

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World Journal of Meta-Analysis 2015年第3期3卷 142-150页

作者： rebecca L Diekemper Belinda k Ireland Liana r Merz american College of Chest Physicians CHEST Glenview IL 60026 United States The Evidence Doc Pacific MO 63069 United States Center for Clinical Excellence BJC Health Care Saint Louis MO 63108 United States

AIM:To develop a tool to more explicitly assess and document the quality of systematic ***:We developed the Documentation and Appraisal review Tool(DArT)using epidemiologic principles of study design and the following resources:the modified Overview Quality Assessment Questionnaire(modified OQAQ),Assessment of Multiple Systematic reviews(amSTAr),the Cochrane Handbook,and the standards promoted by the Agency for Healthcare research and Quality,and the Institutes of Medicine(IOM).We designed the DArT tool to include the following:more detail to provide guidance and improve standardization of use,an approach to assess quality of systematic reviews addressing a variety of research designs,and additional space for recording notes to facilitate *** underwent multiple rounds of testing with methodologists of varying levels of training and *** on the results of six phases of pilot testing,we revised DArT to improve performance,clarity and *** testing also included comparisons between DArT,and the two most commonly used tools to evaluate the quality of systematic reviews,the modified OQAQ and ***:Compared to amSTAr and modified OQAQ,DArT includes two unique questions and several questions covered by modified OQAQ or amSTAr but not *** OQAQ and DArT had the highest reporting *** amSTAr questions were unclear and elicited inconsistent *** reviewer rationale was most difficult using the modified OQAQ tool,and easiest using *** allowsfor documentation of reviewer rationale,facilitating reconciliation between reviewers and documentation for future *** also provides a comprehensive,systematic approach for reviewers with limited experience with systematic review methodology,to critically analyze systematic *** addition,DArT is the only one of the three tools to explicitly include quality review for biases specific to observational *** is now more widely

关键词： Quality assessment tool Methodology Healthcare research Systematic review Meta-analysis Guidelines

硅橡胶/SiC复合材料非线性电阻及电荷输运特性

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中国电机工程学报 2016年第24期36卷 6647-6653页

作者：杨卓然李忠磊李进杜伯学天津大学电气与自动化工程学院天津市南开区300072

为探索非线性电阻率对Sir/SiC复合材料空间电荷及表面电荷特性的影响,对不同SiC颗粒含量的Sir/SiC复合材料在不同电压下的电阻率以及空间电荷与表面电位进行了测量,分析Sir/SiC复合材料在不同电压下电阻率的变化规律以及电阻率对Sir/Si... 详细信息

为探索非线性电阻率对Sir/SiC复合材料空间电荷及表面电荷特性的影响,对不同SiC颗粒含量的Sir/SiC复合材料在不同电压下的电阻率以及空间电荷与表面电位进行了测量,分析Sir/SiC复合材料在不同电压下电阻率的变化规律以及电阻率对Sir/SiC复合材料电荷积累与消散特性的影响。研究结果表明:当SiC颗粒含量(质量分数)低于10%时,Sir/SiC复合材料的电阻率没有明显的非线性;当SiC颗粒含量高于30%时,Sir/SiC复合材料的电阻率随着电场强度的升高,呈现非线性的变化,并且电场阈值随SiC颗粒含量的增加而降低。在空间电荷极化过程中,较低的电阻率抑制了Sir/SiC复合材料空间电荷的积累;同时在空间电荷去极化过程中,较低的电阻率明显加速了Sir/SiC复合材料空间电荷的消散。此外,较低的电阻率同样对表面电荷消散表现出明显的加速作用。该文初步探究了Sir/SiC复合材料非线性电阻率和电荷特性的变化规律,为直流电缆附件非线性电阻率材料的应用提供了参考。

关键词：直流电缆附件硅橡胶碳化硅颗粒非线性电阻率空间电荷表面电位衰减

Hybrid Active Contour Mammographic Mass Segmentation and Classification

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Computer Systems Science & Engineering 2022年第3期40卷 823-834页

作者： k.Yuvaraj U.S.ragupathy Department of Electronics and Instrumentation Engineering Kongu Engineering College PerunduraiErode638060India

This research implements a novel segmentation of mammographic *** methods are proposed,namely,segmentation of mass based on iterative active contour,automatic region growing,and fully automatic mask selectionbased active contour *** the first method,iterative threshold is performed for manual cropped preprocessed image,and active contour is applied *** overcome manual cropping in the second method,an automatic seed selection followed by region growing is *** that the result is only a few images owing to over segmentation,the third method uses a fully automatic active *** of the segmentation techniques are compared with the manual markup by experts,specifically by taking the difference in their mean ***,the difference in the mean value of the third method is 1.0853,which indicates the closeness of the ***,the proposed method is compared with the existing fuzzy C means and level set *** automatic mass segmentation based on active contour technique results in segmentation with high *** using adaptive neuro fuzzy inference system,classification is done and results in a sensitivity of 94.73%,accuracy of 93.93%,and Mathew’s correlation coefficient(MCC)of 0.876.

关键词： Feature optimization hybrid active contour segmentation mass classification mass feature extraction medical image analysis