检索结果-南通市图书馆

Tailored optical propulsion forces for controlled transport of resonant gold nanoparticles and associated thermal convective fluid flows

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2020年第1期9卷 256-266页

作者： Jose A.Rodrigo Mercedes Angulo Tatiana Alieva Facultad de Ciencias Fisicas Ciudad Universitaria s/nUniversidad Complutense de Madrid28040 MadridSpain

Noble metal nanoparticles illuminated at their plasmonic resonance wavelength turn into heat *** phenomenon has prompted the development of numerous applications in science and *** optical manipulation of such resonant nanoparticles could certainly extend the functionality and potential applications of optothermal *** this article,we experimentally demonstrate optical transport of single and multiple resonant nanoparticles(colloidal gold spheres of radius 200 nm)directed by tailored transverse phase-gradient forces propelling them around a 2D optical *** show how the phase-gradient force can be designed to efficiently change the speed of the *** have found that multiple hot nanoparticles assemble in the form of a quasi-stable group whose motion around the laser trap is also controlled by such optical propulsion *** assembly experiences a significant increase in the local temperature,which creates an optothermal convective fluid flow dragging tracer particles into the ***,the created assembly is a moving heat source controlled by the propulsion force,enabling indirect control of fluid flows as a micro-optofluidic *** existence of these flows,probably caused by the temperature-induced Marangoni effect at the liquid water/superheated water interface,is confirmed by tracking free tracer particles migrating towards the *** propose a straightforward method to control the assembly size,and therefore its temperature,by using a nonuniform optical propelling force that induces the splitting or merging of the group of *** envision further development of microscale optofluidic tools based on these achievements.

关键词： thermal fluid transport

Heat transfer and entropy generation analysis of non-Newtonian fluid flow through vertical microchannel with convective boundary condition

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2019年第9期40卷 1285-1300页

作者： M. MADHU N. S. SHASHIKUMAR B. MAHANTHESH B. J. GIREESHA N. KISHAN Department of Studies and Research in Mathematics Kuvempu University Shankaraghatta 577451 India Department of Mathematics Christ Deemed to be University Bangalore 560029 India Department of Mathematics Osmania University Telangana 500007 India

The entropy generation and heat transfer characteristics of magnetohydrodynamic (MHD) third-grade fluid flow through a vertical porous microchannel with a convective boundary condition are analyzed. Entropy generation due to flow of MHD non-Newtonian third-grade fluid within a microchannel and temperature-dependent viscosity is studied using the entropy generation rate and Vogel's model. The equations describing flow and heat transport along with boundary conditions are first made dimensionless using proper non-dimensional transformations and then solved numerically via the finite element method (FEM). An appropriate comparison is made with the previously published results in the literature as a limiting case of the considered problem. The comparison confirms excellent agreement. The effects of the Grashof number, the Hartmann number, the Biot number, the exponential space-and thermal-dependent heat source (ESHS/THS) parameters, and the viscous dissipation parameter on the temperature and velocity are studied and presented graphically. The entropy generation and the Bejan number are also calculated. From the comprehensive parametric study, it is recognized that the production of entropy can be improved with convective heating and viscous dissipation aspects. It is also found that the ESHS aspect dominates the THS aspect.

关键词： microchannel entropy generation Bejan number third-grade fluid magnetic field

THEORY FOR STEP AND PULSE METHOD OF SUPERCRITICAL fluid CHROMATOGRAPHY

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 1996年第4期4卷 54-62页

作者：赵锁奇王仁安杨光华石油大学（北京）重质油加工国家重点实验室北京 102200 石油大学（北京）重质油加工国家重点实验室北京

1 INTRODUCTIONSupercritical fluid chromatography(SFC),employing supercritical fluid as mobilephase,originated in the 1960’s [1-4].Since 1980’s extensive research work has beenperformed on SFC,chiefly for analytical purposes [5,6].SFC was then adopted for thedetermination of thermodynamic properties such as partial molar volume,and partialmolar enthalpy of solutes in both mobile phase and stationary phase and the solutedistribution coefficient between two phases [7- 11].Partial molar properties can be de-

关键词： supercritical fluid chromatography fugacity step and pulse finite concentration retention time

Unsteady three-dimensional MHD flow of the micropolar fluid over an oscillatory disk with Cattaneo-Christov double diffusion

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2019年第10期40卷 1471-1486页

作者： A.RAUF S.A.SHEHZAD Z.ABBAS T.HAYAT Department of Mathematics COMSATS University Islamabad Sahiwal 57000 Pakistan Department of Mathematics The Islamia University of Bahawalpur Bahawalpur 63100 Pakistan Department of Mathematics Quiad-i-Azam University Islamabad 44000 Pakistan

Cattaneo-Christov heat and mass flux models are considered rather than Fourier and Fick laws due to the presence of thermal and concentration transport hyperbolic phenomena. The generalized form of the Navier-Stokes model is considered in hydromagnetic flow. Three-dimensional (3D) unsteady fluid motion is generated by the periodic oscillations of a rotating disk. Similarity transformations are used to obtain the normalized fluid flow model. The successive over relaxation (SOR) method with finite difference schemes are accomplished for the numerical solution of the obtained partial differential non-linear system. The flow features of the velocity, microrotation, temperature, and concentration fields are discussed in pictorial forms for various physical flow parameters. The couple stresses and heat and mass transfer rates for different physical quantities are explained via tabular forms. For better insight of the physical fluid model, 3D fluid phenomena and two-dimensional (2D) contours are also plotted. The results show that the micropolar fluids contain microstructure having non-symmetric stress tensor and are useful in lubrication theory. Moreover, the thermal and concentration waves in Cattaneo-Christov models have a significance role in the laser heating and enhancement in thermal conductivity.

关键词： three-dimensional (3D) flow micropolar fluid magnetohydrodynamics (MHD) Cattaneo-Christov theory oscillatory disk

Computational fluid dynamics simulation of a novel bioreactor forsophorolipid production

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2017年第6期25卷 732-740页

作者： Xiaoqiang Jia Lin Qi Yaguang Zhang Xue Yang Hongna Wang Fanglong Zhao Wenyu Lu Department of Biochemical Engineering School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China Key Laboratory of Systems Bioengineering (Tianjin University) Ministry of Education Tianjin 300072 China Synthetic Biology Platform Collaborative Innovation Center of Chemical Science and Engineering (Tiarljin) Tianjin 300072 China

This paper describes three-dimensional computational fluid dynamics(CFD) simulations of gas–liquid flow in a novel laboratory-scale bioreactor contained dual ventilation-pipe and double sieve-plate bioreactor(DVDSB)used for sophorolipid(SL) production. To evaluate the role of hydrodynamics in reactor design, the comparisons between conventional fed-batch fermenter and DVDSB on the hydrodynamic behavior are predicted by the CFD methods. Important hydrodynamic parameters of the gas–liquid two-phase system such as the liquid phase velocity field, turbulent kinetic energy and volume-averaged overall and time-averaged local gas holdups were simulated and analyzed in detail. The numerical results were also validated by experimental measurements of overall gas holdups. The yield of sophorolipids was significantly improved to 484 g·L^(-1)with a 320 h fermentation period in the new reactor.

关键词： Bioreactors Gas hold-up Computational fluid dynamics (CFD)Hydrodynamics Sophorolipid production

Synthesis of the fluid machinery network in a circulating water system

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第3期27卷 587-597页

作者： Wei Gao Xiao Feng School of Chemical Engineering and Technology Xi'an Jiaotong University

Energy consumption of the fluid machinery network in a circulating water system takes up a large part of energy consumption in the process industry, so optimization on the network will enhance the economic and environmental performance of the industry. In this paper, a synthesis approach is proposed to obtain the optimal network structure. The effective height curves are used as tools to perform energy analysis, so that the potential placement of water turbines and auxiliary pumps can be determined with energy benefit. Then economic optimization is carried out, by the mathematical model with the total cost as the objective function, to identify the branches for water turbines and auxiliary pumps with economic benefit. In this way, the optimal fluid machinery network structure can be obtained. The results of case study indicate that the proposed synthesis approach to optimize the fluid machinery network will obtain more remarkable benefits on economy, compared to optimizing only the water turbine network or pump network. The results under different flowrates of circulating water reveal that using a water turbine to recover power or adding an auxiliary pump to save energy in branches are only suitable to the flowrate in a certain range.

关键词： fluid machinery network Synthesis approach Flowrate range Network structure

Structural parameter optimization for novel internal-loop iron–carbon micro-electrolysis reactors using computational fluid dynamics

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第4期27卷 737-744页

作者： Lei Zhang Mengyu Wu Yanhe Han Meili Liu Junfeng Niu Department of Environmental Engineering Beijing Institute of Petrochemical Technology Beijing 102617 China Research Center for Eco-Environmental Engineering Dongguan University of Technology Dongguan 523808 China

It is generally recognized that internal-loop reactors are well-developed mass and heat-transfer multiphase flow reactors. However, the internal flow field in the internal-loop reactor is influenced by the structure parameter of the reactor, which has a great effect on the reaction efficiency. In this study, the computational fluid dynamics simulation method was used to determine the influence of reactor structure on flow field, and a volume-offluid model was employed to simulate the gas–liquid, two-phase flow of the internal-loop micro-electrolysis reactor. Hydrodynamic factors were optimized when the height-to-diameter ratio was 4:1, diameter ratio was9:1, draft-tube axial height was 90 mm. Three-dimensional simulations for the water distributor were carried out, and the results suggested that the optimal conditions are as follows: the number of water distribution pipes was four, and an inhomogeneous water distribution was used. According to the results of the simulation,the suitable structure can be used to achieve good fluid mechanical properties, such as the good liquid circulation velocity and gas holdup, which provides a good theoretical foundation for the application of the reactor.

关键词： Iron–carbon micro-electrolysis Internal cycling Computational fluid dynamics Structure design

Superparamagnetic CoFe2O4@Au with High Specific Absorption Rate and Intrinsic Loss Power for Magnetic fluid Hyperthermia Applications

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2019年第6期32卷 719-725页

作者： Sandip Sabale Vidhya Jadhav Shubhangi Mane-Gavade Xiao-Ying Yu Earth and Biological Sciences Directorate PNNLRichland.WA 99352USA Department of Chemistry Jaysingpur College JaysingpurShivaji UniversityKolhapurMS 416101India

CoFe2O4 nanoparticles(NPs)and surface modified with gold(Au)have been synthesized by a thermal decomposition *** obtained NPs and formation of CoFe2O4@Au core–shell(CS)were confirmed by characterizing their structural and optical properties using X-ray powder diffraction(XRD)patterns,Fourier transform infrared spectroscopy,Raman spectroscopy,UV–Visible and photoluminescence *** and compositional studies were carried out using high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy,while the magnetic properties were determined using alternating gradient magnetometer and Mossbauer to define the magneto-structural effects of shell formation on the core *** heating properties of CoFe2O4 and CoFe2O4@Au CS magnetic nanoparticles(MNPs)have been investigated and correlated with magneto-structural *** absorption rate and intrinsic loss power were calculated for these MNPs within the human tolerable range of frequency and amplitude,suggesting their potential in magnetic fluid hyperthermia therapy for possible cancer treatment.

关键词： CoFe2O4@Au Superparamagnetic Specific absorption rate(SAR) Intrinsic loss power(ILP) Magnetic fluid hyperthermia

Vortical structures and wakes of a sphere in homogeneous and density stratified fluid

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2021年第2期33卷 207-215页

作者： Liu-shuai Cao Feng-lai Huang Cheng Liu De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil Engi-neeringShanghai Jiao Tong UniversityShanghai 200240China Ocean College Zhejiang UniversityZhoushan 316021China

Vortical structures and wakes of bluff bodies in homogenous and stratified environment are common and important in ocean *** on the Boussinesq approximation,a thermocline model is proposed to deal with the variable density stratified fluid,and implemented in the commercial software Simcenter STAR-CCM+*** improved delayed detached eddy simulation(IDDES)modeling method is adopted to resolve the coherent vortical structures and turbulent wakes precisely and *** conditions consisting of one homogenous and three stratified fluid cases with different density gradient past a sphere at Reynolds number 3700 are *** show that density stratification has a great impact on the vortical structures,the vertical motion is suppressed and internal waves will be induced and propagated,which is very different with that of homogenous *** the stratification strength increases,the vortical structures are gradually flattened,the asymmetry and anisotropy between vertical and horizontal motions are enhanced.

关键词： Vortical structures wakes sphere homogenous stratified fluid