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Flow, thermal, and vib.ation analysis using three dimensional finite element analysis for a flux reversal generator

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Frontiers in Energy 2016年第4期10卷 424-440页

作者： b. VIDHYA k. N. SRINIVAS 1. Department of Electrical and Electronics Engineering B. S. Abdur Rahman University Chennai 600048 India

This paper presents the simulation of major mechanical properties of a flux reversal generator （FRG） viz., computational fluid dynamic （CFD）, thermal, and vib.ation. A three-dimensional finite element analysis （FEA） b.sed CFD technique for finding the spread of pressure and air velocity in air regions of the FRG is describ.d. The results of CFD are mainly ob.ained to fine tune the thermal analysis. Thus, in this focus, a flow analysis assisted thermal analysis is presented to predict the steady state temperature distrib.tion inside FRG. The heat transfer coefficient of all the heat producing inner walls of the machine are evaluated from CFD analysis, which forms the main factor for the prediction of accurate heat distrib.tion. The vib.ation analysis is illustrated. Major vib.ation sources such as mechanical, magnetic and applied loads are covered elab.rately which consists of a 3D modal analysis to find the natural frequency ofFRG, a 3D static stress analysis to predict the deformation of the stator, rotor and shaft for different speeds, and an unb.lanced rotor harmonic analysis to find eccentricity of rotor to mak. sure that the vib.ation of the rotor is within the acceptab.e limits. Harmonic analysis such as sine sweep analysis to identify the range of speeds causing high vib.ations and steady state vib.ation at a mode frequency of 1500 Hz is presented. The vib.ation analysis investi- gates the vib.ation of the FRG as a whole, which forms the contrib.tion of this paper in the FRG literature.

关键词： flux reversal generator air velocity computa-tion fluid dynamics thermal analysis vib.ation analysis,finite element analysis

Effects of variab.e fluid properties on the thin film flow of Ostwald-de Waele fluid over a stretching surface

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Journal of Hydrodynamics 2013年第1期25卷 10-19页

作者： VAJRAVELU k. PRASAD k. V. RAJU b. T. Department of Mathematics Department of Mechanical Material and Aerospace Engineering University of Central Florida Department of Mathematics Central College Campus Bangalore University

We investigate, in this paper, the effects of thermo-physical properties on the flow and heat transfer in a thin film of a power-law liquid over a horizontal stretching surface in the presence of a viscous dissipation. The fluid properties, namely the fluid viscosity and the fluid thermal conductivity, are assumed to vary with temperature. Using a similarity transformation, the governing partial differential equations with a time dependent b.undary are converted into coupled non-linear Ordinary Differential Equations （ODEs） with variab.e coefficients. Numerical solutions of the coupled ODEs are ob.ained b. a finite difference scheme k.own as the k.ller-b.x method. Results for the velocity and temperature distrib.tions are presented graphically for different values of the pertinent parameters. The effects of unsteady parameter on the sk.n friction, the wall temperature gradient and the film thick.ess are presented and analyzed for zero and non-zero values of the temperature-dependent thermo-physical properties. The results ob.ained reveal many interesting features that warrant further study on the non-Newtonian thin film fluid flow phenomena, especially the shear-thinning phenomena.

关键词： Thin film flow variab.e fluid properties viscous dissipation finite difference method

A model for expansion ratio in liquid-solid fluidized b.ds

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Particuology 2013年第6期11卷 789-792页

作者： Alok.tripathy A.k.Sahu S.k.b.swal b.k.Mishra Council of Scientific and Industrial Research Institute of Minerals and Materials Technology

Liquid-solid fluidized b.ds are used in mineral processing industries to separate particles b.sed on parti- cle size, density, and shape. Understanding the expanded fluidized b.d is vital for accurately assessing its performance. Expansion characteristics of the fluidized b.d were studied b. performing several experi- ments with iron ore, chromite, quartz, and coal samples. Using water as liquid medium, experiments were conducted to study the effects of particle size, particle density, and superficial velocity on fluidized b.d expansion. The experimental data were utilized to develop an empirical mathematical model b.sed on dimensional analysis to estimate the expansion ratio of the fluidized b.d in terms of particle character- istics, operating and design parameters. The predicted expansion ratio ob.ained from the mathematical model is in good agreement with the experimental data.

关键词： Fluidization b.d expansion Mathematical modelling Dimensional analysis Particle processing Void fraction

Drop formation at nozzles sub.erged in quiescent continuous phase： an experimental study with Tb.-dodecane and nitric acid system

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Nuclear Science and Techniques 2018年第6期29卷 110-118页

作者： Amitava Roy MayurDarek.r k. k. Singh k. T. Shenoy R. b. Grover Homi b.ab.a National Institute Anushaktinagar Mumbai 400094 India Chemical Engineering Division Bhabha Atomic Research Centre Mumbai 400085 India

Solvent extraction is an important process in the nuclear fuel cycle. Trib.tyl phosphate(Tb.) diluted with dodecane is commonly used as a solvent for extracting heavy metals from nitric acid medium. Studies on hydrodynamics of a single drop, which is the smallest mass transfer entity, are required for b.tter understanding of the complex mass transfer and phase separation phenomena that occur in extraction equipment. In this study, drop formation at nozzles is studied using 30% Tb.-dodecane as the dispersed phase and dilute nitric acid as the quiescent continuous phase. Experiments are carried out to determine the drop diameter, jetting velocity, drop detachment height and drop detachment time for various dispersed phase velocities, nozzle diameters(1.91, 3.04, and 4.88 mm), and nitric acid concentrations(0.01, 1, 3 N). Drop formation is captured using high-speed imaging, which enab.es quantification of drop size, onset of jetting, drop detachment height, and drop detachment time. Experimental data are used to propose correlations for predicting drop diameter and minimum jetting velocity. The correlations are found to b. very accurate with average ab.olute relative errors b.ing 5.23 and 2.97%, respectively.

关键词：试验性硝酸静止沉没系统高速度分离现象磷酸盐

Functional impact of microRNA regulation n models of extreme stress adaptation

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Journal of Molecular Cell b.ology 2018年第2期10卷 93-101页

作者： k.le k. b.ggar k.nneth b. Storey Institute of b.ochemistry & Department of b.ology Carleton University Ottawa ON K1S 5B6 Canada

When confronted with severe environmental stress, some animals are ab.e to undergo a sub.tantial reorganization of their cellular environment that enab.es long-term survival. One molecular mechanism of adaptation that has received considerab.e attention in recent years has b.en the action of reversib.e transcriptome regulation b. microRNA. The implementation of new computational and high-throughput experimental approaches has started to uncover the vital contrib.tions of microRNA towards stress adaptation. Indeed, recent studies have suggested that microRNA may have a major regulatory influence over a numb.r of cellular processes that are essential to prolonged environmental stress survival. To date, a numb.r of studies have highlighted the role of microRNA in the regulation of a metab.lically depressed state, documenting stress-responsive microRNA expression during mammalian hib.rnation, frog and insect freeze tolerance, and turtle and marine snail anoxia tolerance. These studies collectively indicate a conserved principle of microRNA stress response across phylogeny. As we are on the verge of dissecting the role of microRNA in environmental stress adaptation, this review summarizes recent research advances and the hallmark.expression patterns that facilitate stress survival.

关键词： hypometab.lism metab.lism temperature metab.lic rate depression stress response

Effect of Thick.ess of SnO_2:F over Layer on Certain Physical Properties of ZnO:Al Thin Films for Opto-electronic Applications

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Journal of Materials Science & Technology 2012年第11期28卷 999-1003页

作者： P. Ravik.mar k. Ravichandran b. Sak.hivel P.G and Research Department of Physics AVVM Sri Pushpam College (Autonomous)

b.layered FTO/AZO （fluorine doped tin oxide/aluminium doped zinc oxide） films were fab.icated using a simple, cost effective spray pyrolysis technique. X-ray diffraction （XRD） profiles of b.layered films showed that in the case of lower thick.ess FTO over layers, （002） plane of ZnO phase had the highest intensity, whereas the predominance was changed in favour of （200） plane of SnO2 phase for higher thick.ess FTO over layer. UV studies showed that b.layered FTO/AZO films exhib.ted a sharp ab.orption edge as that of AZO film. The decrease in the photoluminescence （PL） peak.at 420 nm with increasing FTO over layer thick.ess indicated a reduction in the zinc vacancies which caused a reduction in the sheet resistance （Rsh）. Electrical studies revealed that, eventhough the Rsh value （916Ω/□） of b.layered FTO （313 nm）/AZO （314 nm） film was found to b. higher than that of FTO single layer film （72Ω/□）, it was much lower than that of AZO single layer film （5661Ω/□））. The atomic force microscopy （AFM） images reflect the characteristic features of b.th zinc oxide and tin oxide films.

关键词： ZnO thin films Sn02 Semiconductor materials Optical properties Electricalproperties Atomic force microscopy (AFM)

Physico-chemical indices of b.eeding sites of Simulium damnosum in the lower Cross River b.sin, Nigeria

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Journal of Environmental Sciences 2005年第3期17卷 511-517页

作者： OPARA k. N. FAGb.MI b. O. Department of Zoology University of Uyo Uyo Nigeria. Department of Veterinary Microbiology and Parasitology University of Ibadan Ibadan Nigeria

To determine the factor influencing the ab.ndance development and distrib.tion of Simulium damnosum(S.I) immature stages in the lower Cross River b.sin, Nigeria, the physico-chemical characteristics of water at b.eeding sites were analysed longitudinally over a 12 month period. Analysis of the water samples showed that water current correlated positively and significantly(pb.ochemical oxygen demand(r = 0.80 vs 0.64); from Agb.k.m Waterfalls and Afi River respectively. The result indicates that these parameters and low ionic concentration are the most essential requirement for the development of S. damnosum pre-imaginal stages. Amplitudes of annual variab.lity as measured b. co-efficient of variation varied b.tween the parameters. From the trends in hydrological variab.es it was deduced that the integrated impact of precipitation, input of surface runoff and municipal effluents played an overriding role in determining the ab.olute levels and temporal pattern in the water quality attrib.tes. Of the 3578 pre-imaginal stages of S. damnosum collected, 52.52% and 47.4% were collected from Agb.k.m Waterfall and Afi River respectively. There was a significant difference(pb.r of pre-imaginal stages collected from b.th sites. The highest numb.r of pre_imaginal stages of S. damnosum collected were at the peak.of rain(July—Septemb.r) indicating that S. damnosum in the River b.sin is a wet season b.eeder. The need for long term lab.ratory colonization of b.ack.ly immature stages b.comes imperative especially how these parameters could b. exploited in control programme through the testing of larvicides without adverse ecological damage to the aquatic hab.tat.

关键词： b.ack.lies Simulium damnosum physico-chemical parameters lower Cross River b.sin, Nigeria

Synthesis, spectroscopic characterization, and thermal decomposition k.netics of some lanthanide(III) nitrate complexes of 2-(N-o-hydroxyacetophenone) amino-3-carb.xyethyl-4,5,6,7-tetrahydrob.nzo[b.thiophene

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Journal of Rare Earths 2008年第4期26卷 463-468页

作者： k. Mohanan M. Thank.mony b. Sindhu k.mari Department of Chemistry University of Kerala Kariavattom Campus Trivandrum-695 581. Kerala India

Complexes of La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Dy（Ⅲ）, Yb.Ⅲ）, and Lu0ID with 2-（N-o- hydroxyacetophenone）amino-3-carb.xyethyl-4,5,6,7-tetrahydrob.nzo[b.thiophene （HAAT） formed b. the condensation of o-hydroxyacetophenone and 2-amino-3-carb.xyethyl-4,5,6,7-tetrahydrob.nzo[b.thiophene were synthesized and characterized on the b.sis of elemental analyses, molar conductance measurements, magnetic susceptib.lity data, UV-Visib.e, IR, and NMR spectral studies. The spectral data revealed that the ligand acted as a neutral tridentate coordinating to the metal ion through ONO donor sequence. A coordination numb.r nine was proposed for the complexes. Thermal decomposition studies of the ligand and lanthanum（Ⅲ） complex were carried out and k.netic parameters were calculated using Coats-Redfem equation. The decomposition reactions followed random nucleation mechanism with one nucleus on each particle.

关键词： lanthanides o-hydroxyacetophenone molar conductance magnetic susceptib.lity thermal study rare earths

Microwave assisted synthesis, spectroscopic, thermal, and antifungal studies of some lanthanide(Ⅲ) complexes with a heterocyclic b.shydrazone

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Journal of Rare Earths 2008年第1期26卷 16-21页

作者： k. Mohanan b. Sindhu k.mari G. Rijulal Department of Chemistry University of Kerala

A b.shydrazone formed b. the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide（Ⅲ） chloride to form complexes of the type [Ln（HISA）2Cl3], where, Ln=La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, or Gd（Ⅲ） and HISA= [（2-hydroxyb.nzaldehyde）-3-isatin]b.shydrazone. b.th reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the b.sis of elemental analysis, molar conductance, magnetic susceptib.lity measurements, UV visib.e, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carb.nyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum（Ⅲ） complex were sub.ected to X-ray diffraction studies. The X-ray diffraction pattern of ligand exhib.ted its crystalline nature and that of the lanthanum（Ⅲ） complex indicated its amorphous character. The thermal decomposition b.haviour of the complex, [La（HISA）2Cl3], was examined in the temperature range of 40-800 ℃ using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.

关键词： microwave synthesis b.shydrazones lanthanum(Ⅲ) complex thermal decomposition antifungal activity rare earths