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Effect of wall temperature modulation on the heat transfer characteristics of droplet-train flow inside a rectangular microchannel

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Chinese Journal of Chemical Engineering 2020年第3期28卷 685-697页

作者： vivekanand s.v.B.,raju v.r.k. Department of Mechanical Engineering National Institute of TechnologyWarangalTelangana 506004India

The numerical studies of water–oil two-phase slug flow inside a two-dimensional vertical microchannel subjected to modulated wall temperature boundary conditions have been discussed in the present *** researchers have contributed their efforts in exploring the characteristics of Taylor flows inside microchannel under constant wall heat flux or isothermal wall ***,there is no study available in the literature which discusses the impact of modulated thermal wall boundary conditions on the heat transfer behavior of slug flows inside ***,to bridge this gap,an effort has been made to understand the heat transfer characteristics of the flow under sinusoidal wall temperature ***,a single phase flow and heat transfer study was performed in microchannels,and the results of the fully developed velocity profile and heat transfer rate were validated with benchmark analytical *** an optimal selection of the combination of sinusoidal thermal wall boundary conditions has been made for the two-phase slug flow ***,the effects of amplitude(0 bεb 0.03)and frequency(0 bωb 750πrad·s-1)of the sinusoidal wall temperature profile on the heat transfer have been studied using the optimal combination of the wall boundary *** results of the numerical study using modulated temperature conditions on channel walls showed a significant improvement in the heat transfer over liquid-only flow by approximately 50%as well as over two-phase flow without wall temperature *** non-dimensional temperature contours obtained for different cases of temperature modulation clearly explain the root cause of such improvement in the heat ***,the results based on the hydrodynamics of the flow have also been reported in terms of variation of droplet shapes and film *** influence of Capillary number on the film thickness as well as heat transfer rates has also been *** addition,the measured fil

关键词： Heat transfer Microchannel Modulation surface tension Taylor flow

Getting physical with medical education:Exercise based virtual anatomy review classes for medical students

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World Journal of Methodology 2025年第1期15卷 20-25页

作者： Nadeesha r samarasinghe Taniya s Nagpal Michele L Barbeau Charys M Martin Division of General surgery Faculty of MedicineUniversity of British ColumbiaVancouver V6T 1Z3BCCanada Faculty of kinesiology Sport and RecreationUniversity of AlbertaEdmonton T6G 2R3ABCanada Anatomy and Cell Biology University of Western OntarioLondon N6A 3K7ONCanada Department of Anatomy and Cell Biology Schulich School of Medicine and DentistryThe University of Western OntarioLondon N6A 3K7ONCanada

The benefits of regular physical activity are well ***,few studies have examined the effectiveness of integrating physical activity(PA)into curricula within a post-secondary *** investigate the incorporation of PA into medical curriculum,we developed a series of optional exercise-based review sessions designed to reinforce musculoskeletal(Msk)anatomy course *** synchronous sessions were co-taught by a group fitness instructor and an anatomy *** fitness instructor would lead students through both strength and yoga style exercises,while the anatomy instructor asked questions about relevant anatomical structures related to course material previously *** the sessions,participants were asked to evaluate the classes on their self-reported exam preparedness in improving Msk anatomy knowledge,PA levels,and mental *** participants completed surveys;a majority agreed that the classes increased understanding of Msk concepts(90.0%)and activity levels(97.7%).Many(70.0%)felt that the classes helped reduce *** majority of respondents(90.0%)agreed that the classes contributed to increased feelings of social ***,medical students saw benefit in PA based interventions to supplement Msk course *** with increasing activity levels and promoting health behaviours,integrating PA into medical curriculum may improve comprehension of learning material,alleviate stress and foster social connectivity among medical students.

关键词： Medical education Musculoskeletal Anatomy Exercise Online learning

Application of response surface Methodolody to Prediction of Dilution in Plasma Transferred Arc Hardfacing of stainless steel on Carbon steel

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Journal of Iron and steel research International 2009年第1期16卷 44-53页

作者： v Balasubramanian A k Lakshminarayanan r varahamoorthy s Babu Centre for Materials Joining and research (CEMAJOr) Department of Manufacturing EngineeringAnnamalai UniversityAnnamalai Nagar 608002Tamil NaduIndia

The application of response surface methodology was highlighted to predict and optimize the percentage of dilution of iron-based hardfaced surface produced by the PTA （plasma tratisferred arc welding） process. The experiments were conducted based on five-factor five-level central composite rotatable design with full replication technique and a mathematical model was developed using response surface methodology. Furthermore, the response surface methodology was also used to optimize the process parameters that yielded the lowest percentage of dilution.

关键词： plasma transferred arc hardfacing dilution response surface methodology

Energy conditions of the f(T,B) gravity dark energy model with the validity of thermodynamics

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Communications in Theoretical Physics 2020年第8期72卷 109-118页

作者： s H shekh v r Chirde P k sahoo Department of Mathematics S.P.M.Science and Gilani Arts and Commerce CollegeGhatanjiYavatmalMaharashtra-445301India Department of Mathematics G.S.G.MahavidyalayaUmarkhed-445206India Department of Mathematics Birla Institute of Technology and Science-PilaniHyderabad CampusHyderabad-500078India

In this article, the analysis of Tsallis holographic dark energy(which turns into holographic dark energy for a particular choice of positive non-additivity parameter δ) in modified f(T, B) gravity with the validity of thermodynamics and energy conditions for a homogeneous and isotropic FLrW Universe has been studied. The enlightenment of the field equation towards f(T,B)=αT^m+βB^n, made possible by the fact that the model is purely accelerating,corresponds to q=-0.54(Mamon and Das 2017 Eur. Phys.J.C 77 49). The generalized second law of thermodynamics is valid not only for the same temperature inside the horizon, but also for the apparent horizon for a change in temperature. The essential inspiration driving this article is to exhibit the applicability that the holographic dark energy achieved from standard Tsallis holographic dark energy and the components acquired from f(T, B) gravity are identical for the specific bounty of constants. The analysis of energy conditions confirms that the weak energy condition and the null energy condition are fulfilled throughout the expansion, while violation of the strong energy condition validates the accelerated expansion of the *** the expansion, the model becomes a quintessence dominated model. The dominant energy condition is not observed initially when the model is filled with genuine baryonic matter,whereas it appears when the model is in the quintessence dominated era.

关键词： Tsallis holographic dark energy f(T B)gravity energy conditions thermodynamics

Improving the Economic values of the recycled Plastics Using Nanotechnology Associated studies

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Journal of Materials science & Technology 2014年第9期30卷 854-859页

作者： W.s.khan r.Asmatulu s.Davuluri v.k.Dandin Department of Mechanical Engineering Wichita State University 1845 FairmountWichita KS 67260-0133 USA

recycled polystyrene （Ps） cups were chopped up and separately incorporated with multiwall carbon nanotubes （MWCNTs） and NiZn ferrite （Ni0.6Zn0.4Fe2O4） nanoparticles prior to electrospinning under different conditions. These nanoscale inclusions were initially dispersed well in dimethylformamide （DMF）, and then known amounts of the recycled Ps pieces were added to the dispersions prior to 30 min of sonication followed by 4 h of high-speed agitation at 750 r/min. The thermal, dielectric, surface hydrophobic, and magnetic properties of the resultant nanocomposite fibers were determined by thermal comparative, capacitance bridge, vibrating sample magnetometer （vsM）, and goniometer techniques, respectively. Test results confirmed that the physical properties of recycled nanofibers were significantly increased as a function of the inclusion concentrations, which may be because of their excellent properties. The consumption of polymeric products as well as their waste materials has dramatically grown worldwide. Although plastic recycling, reprocessing, and reusing rates are growing, the physical properties and economic value of recycled plastics are significantly low. Consequently, this work provides a detailed explanation of how to improve recycled plastics, making them into highly valued new nanoproducts for various industrial applications, including filtration, textile, transportation, construction, and energy.

关键词： recycled polystyrene NiZn ferrite Multiwall carbon nanotubes (MWCNTs) Electrospinning Nanocomposite fibers Physical properties

Investigation of Cast Copper structure

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Journal of Harbin Institute of Technology(New series) 2014年第5期21卷 107-111页

作者： r k Mysik s v Brusnitsyn A v sulitsin Ural Federal University

In this paper,the results of exploration macrostructure and microstructure of continuous cast copper bars are shown. Quantitative parameters of copper cast bars depending on the speed of continuous casting are rated. It is fixed that independent of speed of casting the macrocrystalline columnar structure consisting of four zones is formed. By means of raster electron microscopy,the microstructure of cast copper is studied. It is determined that the accumulations of eutectic Cu-Cu2O in the form of lines and gas pores by size from 2 to 35 microns at the boundaries grain are observed. With the use of the transmission electron microscope,specific dislocation configuration on cast copper sub-boundary grains is determined. It indicates to high-temperature strain of cupper in the course of cast bar solidification. The important finding can be used for the design technology of copper continuous casting and plastic working of cast bars.

关键词： copper macrostructure microstructure electronic microscopy hardness cast bar continuous casting defects.

The theoretical study of the efficiency of diffusion deposition of nanoaerosols in the extended range of the Peclet numbers

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Particuology 2023年第6期77卷 47-55页

作者： r.F.Mardanov s.k.Zaripov v.F.sharafutdinov N.I.Lobachevskii Institute of Mathematics and Mechanics Kazan(Volga Region)Federal UniversityKremlevskaya ul.18KazanTatarstan420008Russia

The efficiencies of the diffusion deposition of nanoaerosols for a single fiber for the models of aerosol filter and wire mesh screen are studied numerically in the extended range of the Peclet number *** rectangular periodic cell model for fluid flow and convective-diffusive transport of small aerosol particles is *** of the previous theoretical and experimental studies of single fiber diffusion deposition efficiency were for the case of Pe>*** array with uniform square or chess grid of fibers and of a row of circular cylindrical fibers are considered as the filter and wire mesh screen *** flow and particles transport equations are solved numerically using the Boundary Element *** obtained numerical data are used to derive the approximate formulas for the deposition efficiency in the entire range of the Peclet number for the various porosities of the filter medium or distances between fibers in a wire mesh *** derived dependencies take into account nonlinearity of the deposition efficiency at the low Peclet *** obtained analytical dependencies compare well with the numerical and experimental data.

关键词： Arrayof fibers row of fibers Periodic cell model Convection-diffusion equation single fiber efficiency

Modeling parameters for predicting the fire-induced progressive collapse in steel framed buildings

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resilient Cities and structures 2023年第3期2卷 129-144页

作者： s.venkatachari v.k.r.kodur Department of Civil Engineering National Institute of Technology PuducherryKaraikalIndia Department of Civil and Environmental Engineering Michigan State University3546 Engineering BuildingEast LansingMIUSA

Fire is one of the extreme loading events that a building may experience during its service life and can have severe consequences on the safety of its occupants,first responders,and the *** framed buildings under severe fires can experience high levels of instability at a local or global level,which in turn can lead to the partial or progressive collapse of the ***,in current practice,fire resistance of structures is obtained without due consideration to a number of critical factors,and this is mainly due to the high level of complexity in undertaking advanced analysis of structures under fire *** paper presents a parametric study on a ten-story braced steel framed building subjected to fire exposure wherein six different parameters are evaluated:fire severity,fire spread,load paths,temperature-induced creep,local instability,and analysis *** from validated finite element models are utilized to evaluate the influence of the different parameters and recommend critical parameters to be incorporated in the *** show that the susceptibility of fire-induced progressive collapse significantly depends on the severity of the fire exposure scenario,including fire intensity,fire spread,and extent of ***,accounting for the full effects of transient creep in fire-induced progressive collapse analysis is needed to obtain conservative failure times under severe to very intense fire ***,results from the parametric study infer that the sectional classification of a steel section based on local instability can alter under fire exposure and this effect is more critical in steel columns located in the higher stories of the building;a nonslender column at ambient conditions can transform to a slender section at elevated *** can induce temperature-induced local instability in the column and lead to an early onset of instability at member and structural levels.

关键词： Design fire Fire spread High-temperature creep Local instability Load path system level analysis Progressive collapse

Effect of Dy-substitution on structural and magnetic properties of Mn-Zn ferrite nanoparticles

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Journal of rare Earths 2018年第1期36卷 86-94页

作者： k.v.Zipare s.s.Bandgar G.s.shahane Department of Electronics DBF Dayanand College of Arts and Science

This paper describes the structural and magnetic properties of Dy-substituted Mn-Zn ferrite nano- particles. Mn-Zn-Dy ferrite nanopafficles of the composition ***204 （x- 0.05, 0.1, 0.15 and 0.2） were synthesized by a facile chemical co-precipitation method. The samples were characterized through X-ray diffraction （XrD）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIr）, vibrating sample magnetometer （vsM） and Curie temperature. The XrD patterns confirm the synthesis of single crystalline phase of Mn-Zn-Dy ferrite nanoparticles. Lattice parameter increases with increase in Dy-substitution which confirms the replacement of Fe3＋ ions by Dy3＋ ions. Crystallite size is of the order of 6-8 nm for all these samples. The particle sizes observed from TEM analysis are in good agreement with the XrD values. The magnetic measurements show super- paramagnetic nature of the samples. The saturation magnetization decreases with increase in Dy- concentration and can be correlated to modifications in the A-B exchange interactions as a result of the structural modifications due to Dy-substitution. The Curie temperature for ***204 nano- particles is 124 ℃ and decreases up to 84 ℃with the increase in the Dy-concentration. The decrease in Curie temperature can be attributed to the weakening of the superexchange interaction between A-site and B-site as a result of Dy-substitution. The low value of Curie temperature and higher value of ther- momagnetic coefficient kT shown by these samples makes them suitable for the preparation of tem- perature sensitive ferrofiuid for heat transfer applications.

关键词： Mn-Zn-Dy ferritesstructural characterizationMagnetic propertiesCurie temperaturerare earths