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A Reliable and Accurate Calculation of Excitation Capacitance Value for an Induction Generator Based on Interval Computation Technique

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International Journal of Automation and computing 2011年第4期8卷 429-436页

作者： Rajesh Kumar Thakur Vivek Agarwal Paluri S. V. Nataraj Systems and Control Engineering Interdisciplinary Programme (IDP)Mumbai 400076 India Department of Electrical Engineering IIT-Bombay Powai Mumbai 400076 India

A squirrel cage induction generator （SCIG） offers many advantages for wind energy conversion systems but suffers from poor voltage regulation under varying operating conditions. The value of excitation capacitance （C exct ） is very crucial for the selfexcitation and voltage build-up as well as voltage regulation in SCIG. Precise calculation of the value of C exct is, therefore, of considerable practical importance. Most of the existing calculation methods make use of the steady-state model of the SCIG in conjunction with some numerical iterative method to determine the minimum value of C exct . But this results in over estimation, leading to poor transient dynamics. This paper presents a novel method, which can precisely calculate the value of C exct by taking into account the behavior of the magnetizing inductance during saturation. Interval analysis has been used to solve the equations. In the proposed method, a range of magnetizing inductance values in the saturation region are included in the calculation of C exct , required for the self-excitation of a 3-φ induction generator. Mathematical analysis to derive the basic equation and application of interval method is presented. The method also yields the magnetizing inductance value in the saturation region which corresponds to an optimum C exct（min） value. The proposed method is experimentally tested for a 1.1 kW induction generator and has shown improved results.

关键词： d-q model hull consistency induction generator interval analysis interval arithmetic optimization range of interval realpaver self-excitation transients.

Performance estimation of bi-directional turbines in wave energy plants

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Journal of Thermal Science 2007年第4期16卷 346-352页

作者： S.Anand V.Jayashankar S.Nagata K.Toyota M.Takao T.Setoguchi Department of Electrical Engineering IIT MadrasIndia IOES Saga UniversityJapan Department of Mechanical Engineering Matsue National College of TechnologyJapan Department of Mechanical Engineering Saga UniversityJapan

基于的波浪精力种的震荡的水列(OWC ) 为把灵魂力量变换成柄力量与双向汽轮机的几种类型被设计了。有连接指南翼和固定指南翼的推动汽轮机在印度波浪精力植物被测试了。这在有井鈥檚汽轮机的起始的试验以后。与有一个线性抑制特征的井... 详细信息

基于的波浪精力种的震荡的水列(OWC ) 为把灵魂力量变换成柄力量与双向汽轮机的几种类型被设计了。有连接指南翼和固定指南翼的推动汽轮机在印度波浪精力植物被测试了。这在有井鈥檚汽轮机的起始的试验以后。与有一个线性抑制特征的井鈥檚汽轮机相对照，推动汽轮机有非线性的抑制。这在全面精力变换有重要效果从向电线招手。优化波浪精力植物与在大量流动系数上的线性抑制和好效率要求一台汽轮机。这个工作描述如此的一个图案怎么能用固定指南翼推动汽轮机被做。印度波浪精力植物被用作案例研究。

关键词：双向涡轮压差流率冲力式涡轮机

Computerized geochemical modeling of burial diagenesis of the Eocene turbidite reservoir elements：Urucutuca Formation,Espirito Santo Basin,southeastern Brazil passive margin

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Journal of Palaeogeography 2018年第4期7卷 363-377页

作者： Marcos Antonio Klunk Sudipta Dasgupta Rommulo Vieira Conceicao Institute of Isotope Geology Federal University of Rio Grande do SulPorto AlegreBrazil Department of Earth Sciences Indian Institute of Technology (IIT) BombayMumbai India

The computerized geochemical modeling, a useful tool to understand the diagenetic processes influencing the quality of hydrocarbon reservoirs, is performed by using different modules of computer codes based on the thermodynamic and chemical kinetic principles and their associated parameters. As observed in the reservoir lithofacies deposited from the marine sediment-gravity flows, a case study of diagenesis is presented here from the Espírito Santo Basin in southeastern Brazil. The study uses the Geochemist＇s Workbench（GWB～（TM））, PHREEQC～（TM） and TOUGHREACT～（TM） computation packages. The comparison of performances of these packages demonstrates the convergence of results from the software-based geochemical modeling with the petrographic observation of dissolution, albitization, kaolinization, and the precipitation of calcite and dolomite. Moreover, with limited data points, e.g., the sedimentary petrographic data acquired from limited number of boreholes, the computer simulation establishes itself to be a powerful quantitative method estimating the degree and type of diagenetic alteration of turbidite reservoir bodies in contact with a source of saline-water influx associated with salt ***, using the limited petrographic data points, the geochemical computer-simulation method can even be utilized and extrapolated for areas where similar geological context is interpreted but no borehole data are available. Hence, porosity of turbidite reservoir lithofacies can be predicted in relation to the spatial distribution of dissolution, kaolinization, and albitization of feldspars and authigenic carbonate precipitation.

关键词： Sandstone diagenesis Computerized diagenetic modeling Turbidite reservoir GWB PHREEQC TOUGHREACT

Turned Trochoidal Disturbance on a Liquid Jet Surface

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Chinese Journal of Mechanical Engineering 2014年第4期27卷 846-852页

作者： SADIK Shalom KIRZHNER Felix KRAMARENKO Denis Department of Mechanical Engineering ORT Braude College Division of Environmental Water and Agricultural Engineering Faculty of Civil and Environmental EngineeringTechnion-IIT Haifa 32000 Israel Biotechnology Engineering ORT Braude College

This paper shows that a turned trochoidal function disturbance may lead to peripheral drops production. The resulting model is used to describe that a turned trochoidal disturbance leads to peripheral drops production on the liquid jet surface without the necessity for superimposed disturbances. The trochoid is a non-unique parametric function. Only non-unique parametric functions disturbances may lead to peripheral drops production. The trochoidal function disturbance is decomposed to Fourier series. Every Fourier element receives an amplification factor in accordance to the Rayleigh inviscid jet model. Peripheral drops are received on the jet surface. The paper shows that all trochoidal disturbance functions, prolate cycloid, cycloid and curtate cycloid have a capability of peripheral drops producing. A limited capability of peripheral drops production is introduced for the trochoidal curtate cycloid. Produced drops size are reduced for increasing the jet velocity and wave number. Smaller drops are also received by transition from the prolate cycloid to curtate cycloid disturbance.

关键词： drops liquid jet trochoidal function

Embeddings of Almost Hermitian Manifold in Almost Hyper Hermitian Manifold and Complex (Hypercomplex) Numbers in Riemannian Geometry

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Applied Mathematics 2014年第16期5卷 2464-2475页

作者： Alexander A Ermolitski iit-BSUIR Minsk Belarus

Tubular neighborhoods play an important role in differential topology. We have applied these constructions to geometry of almost Hermitian manifolds. At first, we consider deformations of tensor structures on a normal tubular neighborhood of a submanifold in a Riemannian manifold. Further, an almost hyper Hermitian structure has been constructed on the tangent bundle TM with help of the Riemannian connection of an almost Hermitian structure on a manifold M then, we consider an embedding of the almost Hermitian manifold M in the corresponding normal tubular neighborhood of the null section in the tangent bundle TM equipped with the deformed almost hyper Hermitian structure of the special form. As a result, we have obtained that any Riemannian manifold M of dimension n can be embedded as a totally geodesic submanifold in a Kaehlerian manifold of dimension 2n (Theorem 6) and in a hyper Kaehlerian manifold of dimension 4n (Theorem 7). Such embeddings are “good” from the point of view of Riemannian geometry. They allow solving problems of Riemannian geometry by methods of Kaehlerian geometry (see Section 5 as an example). We can find similar situation in mathematical analysis (real and complex).

关键词： Riemannian Manifolds Almost Hermitian and Almost Hyper Hermitian Structures Tangent Bundle

Estimating statistics of sky brightness using radio interferometric observations

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维普期刊数据库

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Research in Astronomy and Astrophysics 2019年第4期19卷 119-136页

作者： Prasun Dutta Meera Nandakumar Department of Physics IIT (BHU) Varanasi

Radio interferometers are used to construct high resolution images of the sky at radio frequencies and are the key instruments for accessing the statistical properties of the evolution of neutral hydrogen over cosmic time. Here we use simulated observations of the model sky to assess the efficacy of different estimators of the large-scale structure and power spectrum of the sky brightness distribution. We find that while the large-scale distribution can be reasonably estimated using the reconstructed image from interferometric data, estimates of the power spectrum of the intensity fluctuations calculated from the image are generally biased. This bias is found to be more pronounced for diffuse emission. The visibility based power spectrum estimator, however, gives an unbiased estimate of the true power spectrum. This work demonstrates that for an observation with diffuse emission the reconstructed image can be used to estimate the large-scale distribution of the intensity, while to estimate the power spectrum, visibility based methods should be *** the upcoming experiments aimed at measuring the evolution of the power spectrum of the neutral hydrogen distribution, this is a very important result.

关键词： instrumentation:interferometers methods:data analysis techniques:interferometric

Foraminiferal biostratigraphy of lignite mines of Kutch,India:Age of lignite and fossil vertebrates

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Journal of Palaeogeography 2014年第1期3卷 90-98页

作者： Pratul Kumar Saraswati Sonal Khanolkar Dalta Surya Narayana Raju Suryendu Dutta Santanu Banerjee Department of Earth Sciences IIT Bombay M. S. R. Residency Pragati Marg

The lignite deposits of Kutch, India are stratigraphically referred to the Naredi Formation and considered to be Early Eocene in age. The biostratigraphy of the older mine at Panandhro and a newly opened mine at Matanomadh has constrained the upper age limit of lignite to the early Bartonian. Its lower age may extend to the late Lutetian. Temporally the formation of lignite corresponds to the warming event of the Middle Eocene and suggests a humid climate at the onset of the warming. The previous palynological studies have already suggested dominance of tropical angiospermic pollen. A diverse assemblage of fossil whales and other vertebrates, many of them supposedly the oldest representatives, were reported from Panandhro mine. These were initially assigned to the Early Eocene and later to the Lute? tian age. The present biostratigraphic study revises their age to the Early Bartonian.

关键词： Eocene vertebrates Kutch India lignite biostratigraphy

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双通线加热的热力学及实验分析(英文)

Journal of Marine Science and Application 2011年第2期10卷 190-198页

作者： Pankaj Biswas N. R. Mandal O. P. Sha M. M. Mahapatra Department of Mechanical Engineering iit Department of Ocean Engineering & Naval Architecture iit

The present investigation deals with process analysis of oxy-acetylene flame assisted double pass line heating for varying plate thickness. oxy-acetylene flame as the heat source for multi pass line heating to achieve 3-D bending of plates with varying thicknesses was studied. The oxy-acetylene flame was modeled as the moving heat source in the FEM analysis. The transient thermal histories were predicted taking into account the temperature dependent thermo-mechanical properties. A comparative study between single pass and double pass line heating residual deformation was also carried out. The temperature distribution and residual deformations predicted by the numerical model developed in the present work compared fairly well with those of the experimental ones.

关键词：热机械性能实验分析加热板双通乙炔火焰移动热源有限元分析火焰模型

Change Detection of Desert Sand Dunes: A Remote Sensing Approach

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Advances in Remote Sensing 2014年第1期3卷 10-22页

作者： Surender Varma Vatsal Shah Biplab Banerjee Krishna Mohan Buddhiraju Center of Studies in Resources Engineering IIT Bombay Mumbai India ElectricalEnginering IIT Bombay Mumbai India

Deserts are one of the major landforms on the Earth. While deserts occupy about one-fifth of Earth’s land surface, they have been studied to a much lesser extent. All over the world, desert landforms are expanding ever rapidly and more and more human settlements are finding place in desert regions for habitation. Thus, quantifying and monitoring dunes becomes more relevant from a managerial perspective. Analyzing desert areas using satellite imagery is a challenging task due to weak textural differences and nearly homogeneous spectral responses in most parts of the terrain. In this paper, a post-clustering methodology for change detection of desert sand dunes is proposed. Features based on Radon spectrum are used to cluster dunes of various orientations. These clustered boundaries are used to detect if there are any changes occurring in the dune regions. In the experiments, remote sensing data covering various dune regions of the world are observed for possible changes in dune orientations. In all the cases, it is seen that there are no major changes in desert dune orientations since three decades.

关键词： Change Detection Desert Land Forms Monitoring Sand Dunes