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protection and Control of Modern power Systems 2018年第1期3卷 79-92页

作者： p.k.Dash R.k.patnaik S.p.Mishra Siksha O Anusandhan University Khandagiri SquareBhubaneswarOdisha 751030India GMR Institute of Technology RajamAndhra Pradesh 532127India

With an aim to improve the transient stability of a DFIG wind farm penetrated multimachine power system(MpN),an adaptive fractional integral terminal sliding mode power control(AFITSMpC)strategy has been proposed for the unified power flow controller(UpFC),which is compensating the *** proposed AFITSMpC controls the dq-axis series injected voltage,which controls the admittance model(AM)of the *** a result the power output of the DFIG stabilizes which helps in maintaining the equilibrium between the electrical and mechanical power of the nearby *** the rotor angular deviation of the respective generators gets recovered,which significantly stabilizes the *** proposed AFITSMpC for the admittance model of the UpFC has been validated in a DFIG wind farm penetrated 2 area 4 machine power system in the MATLAB *** robustness and efficacy of the proposed control strategy of the UpFC,in contrast to the conventional pI control is vindicated under a number of intrinsic operating conditions,and the results analyzed are satisfactory.

关键词： Adaptive fractional integral terminal sliding mode power control Doubly fed induction generator Multimachine power network Unified power flow controller

A 4-quadrant Curvelet Transform for Denoising Digital Images

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International Journal of Automation and computing 2013年第3期10卷 217-226页

作者： p. k. parlewar k. M. Bhurchandi Department of Electronic and Communication Engineering Ramdeobaba College of Engineering and Management Department of Electronic Engineering Visvesvaraya National Institute of Technology

The conventional discrete wavelet transform （DWT） introduces artifacts during denoising of images containing smooth curves. Finite ridgelet transform （FRIT） solved this problem by mapping the curves in terms of small curved ridges. However, blind application of FRIT all over an image is computationally heavy. Finite curvelet transform （FCT） selectively applies FRIT only to the tiles containing small portions of a curve. In this work, a novel curvelet transform named as 4-quadrant finite curvelet transform （4QFCT） based on a new concept of 4-quadrant finite ridgelet transform （4QFRIT） has been proposed. An image is band pass filtered and the high frequency bands are divided into small non-overlapping square tiles. The 4QFRIT is applied to the tiles containing at least one curve element. Unlike FRIT, the 4QFRIT takes 4 sets of radon projections in all the 4 quadrants and then averages them in time and frequency domains after denoising. The proposed algorithm is extensively tested and benchmarked for denoising of images with Gaussian noise using mean squared error （MSE） and peak signal to noise ratio （pSNR）. The results confirm that 4QFCT yields consistently better denoising performance quantitatively and visually.

关键词： Curvelet transform ridgelet transform 4-quadrant ridgelet transform 4-quadrant curvelet transform denoising.

Impedance spectroscopy study of Na_(2)SmV_(5)O_(15) ceramics

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Journal of Advanced Ceramics 2014年第1期3卷 1-6页

作者： p.S.DAS p.k.CHAkRABORTY Banarji BEHERA N.k.MOHANTY R.N.p.CHOUDHARY Department of physics Midnapore CollegeMidnapore 721101India School of physics Sambalpur UniversityBurla 768019SambalpurOdishaIndia Department of physics ITERSiksha“O”Anusandhan UniversityBhubaneswar 751030OdishaIndia

The polycrystalline Na_(2)SmV_(5)O_(15)(NSV),a new member of the tungsten bronze(TB)family,was prepared by a mixed-oxide *** room-temperature X-ray diffraction(XRD)confirmed the formation of single phase compound with orthorhombic crystal *** scanning electron microscopy(SEM)analysis indicated that the compound has homogeneous micrograph with a uniform distribution of small grains over the entire surface of the *** analysis of impedance spectra of NSV in a low-temperature range(-100℃to 100℃)at different frequencies exhibited interesting electrical properties like the contribution of bulk effect in conduction *** study of imaginary part of the impedance at different temperatures showed existence of relaxation peak with its shift towards higher frequency on increasing *** suggested the presence of frequency and temperature dependent relaxation process in the *** loss peak spectra were found to abide by Arrhenius law with small activation energy of 0.12 *** temperature dependence of AC and DC electrical conductivity(σ_(AC) and σ_(DC))was also obtained.

关键词： solid-state reaction microstructure impedance conductivity

Vibration of an infinite inhomogeneous transversely isotropic viscoelastic medium with cylindrical hole

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Applied Mathematics and Mechanics(English Edition) 2008年第3期29卷 367-378页

作者： D.p.Acharya Indrajit Roy p.k.Biswas 109/3 Kailash Roy Chowdhury RoadBarrackporeKolkata 700120WBIndia Brahmapara SimuraliNadia 741248WBIndia Department of Mathematics Kanchrapara CollegeKanchraparaWBIndia

This paper investigates the influences of higher order viscoelasticity and the inhomogeneities of the transversely isotropic elastic parameters on the disturbances in an infinite medium, caused by the presence of a transient radial force or twist on the surface of a cylindrical hole with circular cross section. Following Voigt＇s model for higher order viscoelasticity, the nonvanishing stress components valid for a transversely isotropic and higher order viscoelastic solid medium have been deduced in terms of radial displacement component. Considering the power law variation of elastic and viscoelastic parameters, the stress equation of motion has been developed. Solving this equation under suitable boundary conditions, due to transient forces and twists, radial displacement and relevant stress components have been determined in terms of modified Bessel functions. The problem for the presence of transient radial force has been numerically analysed. Modulations of displacement and stresses due to different order of viscoelasticity and inhomogeneity have been graphically depicted. The numerical study of the disturbance caused by the presence of twist on the surface may be similarly done but is not pursued in this paper.

关键词： higher order viscoelasticity inhomogeneity and transversely isotropy transient force and twist radial displacement stress components modified Bessel functions

Viscous and Ohmic heating effects in doubly stratified free convective flow over vertical plate with radiation and chemical reaction

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Applied Mathematics and Mechanics(English Edition) 2013年第2期34卷 139-152页

作者： p.GANESAN R.k.SUGANTHI p.LOGANATHAN Department of Mathematics Anna University Chennai

An analysis is carried out to study the combined effects of viscous and Ohmic heating in the transient, free convective flow of a viscous, incompressible, and doubly stratified fluid past an isothermal vertical plate with radiation and chemical reactions. The governing boundary layer equations are solved numerically by an implicit finite difference scheme of the Crank-Nicolson type. The influence of different parameters on the velocity, the temperature, the concentration, the skin friction, the Nusselt number, and the Sherwood number is discussed with graphical illustrations. It is observed that an increase in either the thermal stratification or the mass stratification parameter decreases the velocity. An increase in the thermal stratification increases the concentration and decreases the temperature while an opposite effect is observed for an increase in the mass stratification. An augmentation in viscous and Ohmic heating increases the velocity and temperature while decreases the concentration. The results are found to be in good agreement with the existing solutions in literature.

关键词： thermal stratification mass stratification Ohmic dissipation viscousdissipation chemical reaction radiation

Solvent effects on hydrogen bonding between primary alcohols and esters

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Journal of Zhejiang University-Science A(Applied physics & Engineering) 2006年第11期7卷 1928-1931页

作者： DHARMALINGAM k. RAMACHANDRAN k. SIVAGURUNATHAN p. Department of physics Annamalai University Annamalai Nagar 608002 Tamilnadu India

The interaction by hydrogen bond formation of some primary alcohols （ l-heptanol, l-octanol and l-decanol） with esters （methyl methacrylate, ethyl methacrylate and butyl methacrylate） was investigated in non-polar solvents viz., n-heptane, CC14 and benzene by means of FTIR spectroscopy. Formation constants and free energy changes of complex formation were determined. The dependence of the equilibrium constants and free energy changes of complex formation on the alkyl chain length of both the alcohols and esters are discussed. The solvent interaction between the solute and solvent. effect on the hydrogen bond formation is discussed in terms of specific

关键词： FTIR spectroscopy primary alcohols Esters Hydrogen bonding Solvent effect

Single Crystal Metal Oxide Nanowires as Bio-Chem Sensing probes

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稀有金属材料与工程 2006年第A3期35卷 295-298页

作者： p.Gouma A.Bishop k.k.Iyer Dept of Materials Science & Engineering State University of New YorkStony BrookNY11794-2275USA

Single crystal MoO_3 nanowires were produced using the electrospinning *** resolution transmission electron microscopy (HRTEM) revealed that the 1-D nanostructures are 10nm in diameter,on the order of 1μm～2μm in length, and have an orthorhombic *** has been demonstrated that a nano-network of MoO_3 nanowires exhibits higher sensitivity and an n-type response to NH_3 as compared to the response of a traditional sol-gel *** structure,crystallinity, and sensoric nature of these single-step processed nanowires are discussed.

关键词： single crystal nanowires electrospinning HRTEM sensor

Effect of promoters on dynamics of gas-solid fluidized bed——Statistical and ANN approaches

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China particuology 2007年第6期5卷 401-407页

作者： Y.k. Mohanty k.C. Biswal G.k. Roy B.p. Mohanty Department of Chemical Engineering GIET Gunupur 765 022 Rayagada Orissa India Department of Chemical Engineering NIT Rourkela 769008 Orissa India

In this study, a bubbling fluidized bed column, 99 mm in inside diameter and 960 mm in height, was used to investigate the effect of rod and disc promoters on fluctuation and expansion ratios. Factorial design （statistical approach） and artificial neural network （ANN） models were developed to predict the fluctuation and expansion ratios in this gas-solid fluidized bed with varying gas flow rates, bed heights, particle sizes and densities. The fluctuation and expansion predicted using these statistical and ANN models, for beds with and without promoters, were found to agree well with corresponding experiments. The statistical model was found to be superior to the ANN model due to its ability to take into account both individual and interactive effects. The rod promoters were found to be more effective in reducing bed fluctuation, and in increasing bed expansion at high gas mass velocities.

关键词： Gas-solid fluidized bed Fluctuation ratio Expansion ratio promoter Factorial design Artificial neural network

Effect of dysprosium substitution on structural and dielectric properties of BiFeO_3-pbTiO_3 multiferroic composites

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Journal of Rare Earths 2015年第6期33卷 639-646页

作者： N.k.Mohanty A.k.Behera S.k.Satpathy Banarji Behera p.Nayak Materials Research Laboratory School of Physics Sambalpur University

0.5BiDyxFe1-xO3-0.5pbTiOa（0.5BDxF1-x-0.5pT）（x=0.00, 0.05, 0.10, 0.15, 0.20） multiferroic composites were pre- pared by conventional solid state reaction method. Structural characterization was performed by X-ray diffraction and the mate- rials showed tetragonal structure at room temperature. Surface morphology of the composites was studied by a scanning electron microscope （SEM）. Frequency and temperature dependence of dielectric constant （er） and dielectric loss （tan~） of 0.5BDxF1_x- 0.5pT were measured in a wide range of frequency （100 Hz to 1 MHz） and temperature （25 to 400 ~C）. The analysis of the study showed that the er and tang decreased with increasing frequency in the given range for all the samples which could be explained through the occurrence of dipole relaxation process. The effect of substitution of rare earth element dysprosium （Dy） showed increase in er in all the samples prepared for different concentrations from 0.00 to 0.20. An explanation for high value of er for Dy modified 0.5BiFeO3-0.5pbTiO3 （0.5BF-0.5pT） compared to Gd modified 0.5BF-0.5pT was provided. The variation of AC conductivity with inverse temperature found to obey the Arrhenius equation and the composites showed negative temperature coefficient of resistance （NTCR） behavior. The activation energy was found to be in the range from 0.25 to 0.40 eV for all the studied samples.

关键词： X-ray diffraction dielectric constant tangent loss activation energy rare earths

Influence of coal properties on coal conversion processes-coal carbonization,carbon fiber production,gasification and liquefaction technologies:a review

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International Journal of Coal Science & Technology 2021年第5期8卷 817-843页

作者： k.p.keboletse F.Ntuli O.p.Oladijo Department of Chemical Materials and Metallurgical EngineeringBotswana International University of Science and TechnologyPalapyeBotswana

Coal due to its relatively large quantities and wide distribution worldwide has generated renewed interest in research and development with the aim of establishing coal conversion technologies that are technically reliable,envi-ronmentally and economically *** has proved to be a prominent energy source in emerging markets with increasing energy demand by accounting for the largest increase in the demand of energy amongst all other energy ***-thermore,with its higher mesophase content,coal tar is an appropriate raw material for precursors in the production of carbon ***,whenever a material is put to use,it is important to be able to associate its properties to the behavioral characteristics during a conversion process so as to have a basis for opting for the material in a given process or adjusting the operating conditions in order to optimize the material ***,as with any other material,it is important to be able to relate the properties of coal to its utilization.A review was carried out on the influence of coal properties on four main utilization technologies:gasification,carbonization,liquefaction and carbon fibre *** several properties rank,type,mineral matter content,distribution of trace elements,structural composition and pore structure were found to be most influential on the behavior of coal during conversion processes.

关键词： Coal properties Carbonization Liquefaction Gasification Carbon fibre