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Effects of operating pressure on the key parameters of coal direct chemical looping combustion

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International Journal of Coal Science & Technology 2016年第1期3卷 20-27页

作者： Rahul Wadhwani Bikash Mohanty Department of Chemical Engineering Indian Institute ofTechnology Roorkee Roorkee India

Techno-economic development of chemical looping combustion (CLC) process has been one of the most pursued research areas of the present decade due to its ability to reduce carbon foot print during utilization of coal to generate energy. Based on a 2D computational fluid dynamics model, the present work provides a computational approach to study the effect of operating pressure—a key parameter in designing of CLC reactors, on optimum operating conditions. The effects of operating pressure have been examined in terms of reactors temperature, percentage of fuel conversion and purity of carbon dioxide in fuel reactor exhaust. The simulated results show qualitative agreement with the trends obtained by other investigators during experimental studies.

关键词：关键参数操作压力煤利用直接燃烧流体动力学模型最佳操作条件二氧化碳燃料转换

利用遥感和GIS技术调查滑坡灾害分区——以印度Arunachal Pradesh区Dikrong河流域为例

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水文地质工程地质技术方法动态 2010年第1期 4-16页

作者： Ashish Pandey 葛秀珍（翻译）何雪洲（校对） Water Resource Development and Management Department IIT 247 667 Roorkee India 不详

滑坡是造成损失和破坏最大的自然灾害之一，其诱因主要是地震和／或降雨。目前的研究中，用遥感技术和地理信息系统（GIS）调查Arunachal Pradesh区Dikrong河流域的滑坡灾害分区（LHZ）。用遥感技术和GIS生成了各种主题的地层即斜坡、... 详细信息

滑坡是造成损失和破坏最大的自然灾害之一，其诱因主要是地震和／或降雨。目前的研究中，用遥感技术和地理信息系统（GIS）调查Arunachal Pradesh区Dikrong河流域的滑坡灾害分区（LHZ）。用遥感技术和GIS生成了各种主题的地层即斜坡、影像．线性构造缓冲带、逆断层缓冲区、相对地势图、地质图，土地利用，土地覆盖图。根据各种成因因素（如来源于遥感数据和其他主题图）的相对重要性，将加权评分系统用于滑坡灾害分区LHZ。按照GIS信息，不同等级的主题层被赋给相应的评分值，然后每一个数据层就生成一个“属性图”。给主题层内的每一个等级赋一个序号从0．9的评分值，然后这些属性图的总和乘以相应的权重得出每个单元的滑坡风险指数（（LHI））。经重新调整采用的试错法的权重评级值。使用的LHI阀值是142、165、189和216。经过使用限幅（切断）运算，一幅处理过的LHZA图标出了5个区即：“非常低危险”、“低危险”、“中等程度危险”“高危险”和“非常高危险”。

关键词： GIS 滑坡地貌遥感坡角

Analyzing hydro abrasive erosion in Kaplan turbine:A case study from India

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Journal of Hydrodynamics 2016年第5期28卷 863-872页

作者： Anant Kr.RAI Arun KUMAR Alternate Hydro Energy Centre IIT Roorkee

Sediment flow through hydro turbine causes erosion of hydraulic components resulting in drop of turbine efficiency, parti- cularly in hydropower plants of the Himalayan region. The measurement of erosion and monitoring of sediment flow in turbine are major concerns in erosion study. Attempts have been made to study erosion mainly in Pelton and Francis turbines. In this study, a simple and effective method has been presented to measure erosion in a Kaplan turbine of a run-of-river scheme Chilla hydropower plant in foothills of Himalaya. Recent techniques were used to measure sediment parameters like concentration, size, shape and mineral content. A standard erosion model is applied to estimate the erosion in Kaplan turbine blade, runner chamber and draft tube cone. A calibration factor has been proposed to apply the erosion model for site specific conditions. It has been found that the outer trailing edges of the turbine blade and upper rtmner chamber are most erosion prone zones. Sediment analysis revealed that effective operation can reduce erosion in turbine components. The estimated erosion values from model are found to be consistent with measu- red values. Finally, suggestions for design improvements and effective operation of erosion affected hydropower plants are given.

关键词： turbine sediment erosion measurement IEC 62364 hydropower

Mo^(6+)Modified(K_(0.5)Na_(0.5))NbO_3 Lead Free Ceramics:Structural,Electrical and Optical Properties

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Journal of Materials Science & Technology 2014年第5期30卷 459-465页

作者： Jyoti Rani Piyush Kumar Patel Nidhi Adhlakha Hemant Singh K.L.Yadav Satya Prakash Smart Materials Research Laboratory Department of PhysicsIndian Institute of Technology Roorkee Metallurgical and Materials Engineering Department Indian Institute of Technology Roorkee

Lead free polycrystalline ceramics （K0.5Na0.5）Nb（1-x）MoxO3 （x = 0, 0.02, 0.04, 0.06 and 0.08） have been synthesized via solid state reaction method. The formation of single phase perovskite structure up to 6 mol% of Mo^6＋ has been confirmed by X-ray diffraction pattern. Impedance spectroscopy reveals that bulk resistance decreases with increasing temperature, which indicates negative temperature coefficient of resistance （NTCR） behaviour of the compounds. The diffuse reflectance spectroscopy results indicate a red shift of the band gap energy of K0.5Na0.5NbO3 （KNN, from 4.28 to 3.61 eV） with increasing Mo^6＋ concentration due to structural modification. The photoluminescence spectra of doped samples are composed of two emission bands at room temperature. One emission band is near band edge ultraviolet （UV） emission （354 nm） and other is visible emission band （-397 nm） which may explore the possibility of these ceramics to be used in optical device applications.

关键词： Ceramics Characterization Dielectric constant Impedance spectroscopy Optical band gap

Influence of Sputtering Gas on Morphological and Optical Properties of Magnesium Films

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Journal of Materials Science & Technology 2011年第1期27卷 51-58页

作者： Yogendra K.Gautam Amit K.Chawla Vipin Chawla R.D.Agrawal Ramesh Chandra Department of Metallurgical and Materials Engineering Indian Institute of Technology Roorkee Nano Science Laboratory Institute Instrumentation CentreIndian Institute of Technology Roorkee

The influence of sputtering gas（He Ar） on the structural properties of Mg thin films has been *** optical property（reflectance） that results from the growth of films at varying substrate temperatures（Tsub） was also *** deposited films were characterized by using X-ray diffraction（XRD）,field emission scaning electron microscopy（FE-SEM）,atomic force microscopy（AFM） and UV-Vis-NIR *** smaller crystallite size and lower deposition rate were observed in the presence of Helium atmosphere compared to *** of the films shows 2D hexagonal geometry of grains in the deposition temperature range（Tsub≈50-150℃） in both the sputtering *** surface roughness of the polycrystalline films were found to increase with increase in the deposition temperature of both ambient *** reflectance of Mg films was measured in near infrared region and larger reflectance was observed from Mg films sputtered in He atmosphere compared to that in argon.

关键词： X-ray diffraction(XRD) Atomic force microscopy(AFM) Reflectance Mg films Microstructure

Seismic safety evaluation methodology for masonry building and retrofitting using splint and bandage technique with wire mesh

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Frontiers of Structural and Civil Engineering 2022年第4期16卷 478-505页

作者： Pravin Kumar Venkat Rao PADALU Yogendra SINGH Earthquake Engineering Research Center International Institute of Information Technology Hyderabad(IIIT-H)Telangana 500032India Department of Earthquake Engineering Indian Institute of Technology Roorkee(IITR)Uttarakhand 247667India

The paper presents a seismic safety assessment of unreinforced masonry(URM)building using two *** first approach uses the‘Pier Analysis’method,based on the concept of equivalent lateral stiffness,where in-plane and out-of-plane actions are considered *** second approach is developed with the program SAP2000,where the linear response is evaluated using continuum‘finite element modelling’(FEM).Both methods are compared to evaluate the safety of wall piers and the differences in the outcomes under combined gravitational and lateral seismic *** analysis results showed that few wall elements are unsafe in in-plane and out-of-plane *** is also observed that the pier analysis method is conservative compared to FEM,but can be used as a simplified and quick tool in design offices for safety assessment,with reasonable *** safeguard the URM wall piers under lateral loads,a retrofitting technique is adopted by providing vertical and horizontal belts called splints and bandages,respectively,using welded wire mesh(WWM)*** study using the‘Pier Analysis’shows that the lateral load capacity of unsafe URM piers can be enhanced up to 3.67 times and made safe using the applied retrofitting ***,the retrofitting design methodology and recommendations for application procedures to on-site URM buildings are discussed in detail.

关键词： unreinforced masonry seismic in-plane and out-of-plane forces pier analysis finite element modelling splint and bandage technique with wire mesh

GIS Based Spatial Data Analysis for Landslide Susceptibility Mapping

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Journal of Mountain Science 2008年第1期5卷 52-62页

作者： S.Sarkar Scientist D.P.Kanungo A.K.Patra Pushpendra Kumar Central Building Research Institute Roorkee-247667India Scientist Central Building Research InstituteRoorkee-247667India Research Fellow Central Building Research InstituteRoorkee-247667India

Landslide susceptibility map delineates the potential zones for landslides occurrence. The paper presents a statistical approach through spatial data analysis in GIS for landslide susceptibility mapping in parts of Sikkim Himalaya. Six important causative factors for landslide occurrences were selected and corresponding thematic data layers were prepared in GIS. Topographic maps,satellite image,field data and published maps constitute the input data for thematic layer preparation. Numerical weights for different categories of these factors were determined based on a statistical approach and the weighted thematic layers were integrated in GIS environment to generate the landslide susceptibility map of the area. The landslide susceptibility map classifies the area into five different landslide susceptible zones i.e.,very high,high,moderate,low and very low. This map was validated using the existing landslide distribution in the area.

关键词：地理信息系统山崩磁化系数分析方法

Triaxial strength behaviour of rockmass satisfying Modified Mohr-Coulomb and Generalized Hoek-Brown criteria

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International Journal of Mining Science and Technology 2018年第6期28卷 901-915页

作者： Saurav Rukhaiyar Narendra Kumar Samadhiya Department of Civil Engineering Indian Institute of Technology Roorkee

The triaxial strength of twenty rockmass types was predicted using two non-linear triaxial strength criteria for rockmass i.e. Modified Mohr-Coulomb(MMC) criterion and Generalized Hoek-Brown(GHB)criterion. Four different rockmass classification systems were used for the calculation of MMC criterion parameters while only GSI classification system has been used for calculation of GHB parameters. The representative value of the uniaxial compressive strength and elastic modulus of rockmass have been estimated using probabilistic approach. A hypothetical case of an unsupported tunnel has been analyzed considering both MMC and GHB criteria. The analysis was done using the convergence-confinement method with two different approaches. The first approach predicts the tunnel response using GHB criterion directly. The second approach predicts the tunnel response using equivalent Mohr-Coulomb parameters obtained by linearization of triaxial data points obtained from MMC and GHB criteria. The tunnel response has been estimated in terms of radius of plastic zone, tunnel convergence and tunnel convergence strain. For very poor rockmasses the tunnel response predicted by MMC criterion is less than that predicted by GHB criterion. For poor and fair rockmass, the tunnel response estimated considering both the criteria are comparable except for few cases. Squeezing condition in rockmass has been also evaluated.

关键词： Triaxial strength Modified Mohr-Coulomb criterion Generalised Hoek-Brown criterion Convergence-confinement method

Influence of Sputtering Pressure on the Structure and Mechanical Properties of Nanocomposite Ti-Si-N Thin Films

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Journal of Materials Science & Technology 2010年第8期26卷 673-678页

作者： Vipin Chawla R.Jayaganthan Ramesh Chandra Department of Metallurgical and Materials Engineering & Centre of Nanotechnology Indian Institute of Technology Roorkee Nano Science Laboratory Institute Instrumentation CentreIndian Institute of Technology Roorkee

Nanocomposite Ti-Si-N thin films have been deposited on Si （100） substrate by direct current/radio frequency （DC/RF） magnetron sputtering. The effect of varying deposition parameters on the structure and mechanical properties of Ti-Si-N films has been investigated by characterization techniques such as X-ray dif- fraction （XRD）, field emission scanning electron microscopy （FE-SEM）, atomic force microscopy （AFM） and nanoindentation, respectively. XRD analysis of the thin films exhibit all （111）, （200） and （220） peaks initially with varying sputtering pressure, but （111） peak dominates at higher sputtering pressure. The crystallite size calculated from XRD peaks shows that it increases with increasing sputtering pressure. Microstructural analy- sis reveals that the dense blurred grains transform into uniform grains in the films and shows porosity with increasing sputtering pressure. The surface roughness of the Ti-Si-N films increases with varying sputtering pressure. The hardness and Youngrs modulus values of Ti-Si-N films are 33.7 and 278.6 GPa, respectively, with 0.7 Pa sputtering pressure but it decreases with further increase in sputtering pressure due to an increase in porosity of the films.

关键词： Ti-Si-N films Nanoindentation Microstructural characterization