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Wave propagation responses of porous bi-directional functionally graded magneto-electro-elastic nanoshells via nonlocal strain gradient theory

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应用数学和力学:英文版 2023年第10期44卷 1821-1840页

作者： Xinte WANG Juan LIU Biao HU Bo ZHANG Huoming SHEN School of Mechanics and Aerospace Engineering Southwest Jiaotong UniversityChengdu 610031China School of Civil Engineering Guizhou University of Engineering ScienceBijie 551700Guizhou ProvinceChina

This study examines the wave propagation characteristics for a bi-directional functional grading of barium titanate(BaTiO_(3)) and cobalt ferrite(CoFe_(2)O_(4)) porous nanoshells,the porosity distribution of which is simulated by the honeycomb-shaped symmetrical and asymmetrical distribution functions.The nonlocal strain gradient theory(NSGT) and first-order shear deformation theory are used to determine the size effect and shear deformation,respectively.Nonlocal governing equations are derived for the nanoshells by Hamilton's principle.The resulting dimensionless differential equations are solved by means of an analytical solution of the combined exponential function after dimensionless treatment.Finally,extensive parametric surveys are conducted to investigate the influence of diverse parameters,such as dimensionless scale parameters,radiusto-thickness ratios,bi-directional functionally graded(FG) indices,porosity coefficients,and dimensionless electromagnetic potentials on the wave propagation characteristics.Based on the analysis results,the effect of the dimensionless scale parameters on the dispersion relationship is found to be related to the ratio of the scale parameters.The wave propagation characteristics of nanoshells in the presence of a magnetoelectric field depend on the bi-directional FG indices.

关键词： bi-directional functionally graded(FG) wave propagation dimensionless magneto-electro-elastic(MEE)nanoshell nonlocal strain gradient theory(NSGT) porosity

The Analysis of dimensionless Magnitudes in Economic Science

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Economics World 2018年第4期6卷 279-285页

作者： Odysseas Kopsidas University of Piraeus PiraeusGreece

An economy consists of the economic system of a country or other unit of human society.It includes labor,capital,natural resources,production,trade,distribution and consumption of goods and services in the area where human society is active.These factors give context,content,and determine the conditions and parameters with which the economy operates.When searching with data mining techniques to identify or find out dimensionless groups(DGs)in technical literature,it is possible to meet errors/faults/omissions concerning both,the form and the content of such groups.In the present study,a methodological framework has been developed in terms of a logical flow chart,including 11 activity stages and seven decision nodes,to acquire/process/store/retrieve knowledge for reconstruction and identification of these groups.Case Based Reasoning(CBR),especially modified to meet the needs of this work,has been used for tracing causality paths by similarity and making correction suggestions.Two case examples are presented to prove the functionality of the proposed methodology.Non-dimensional groups are used in engineering but can also be used in economic science.Through this analysis,we can calculate the scale of industrial processes from laboratory to pilot and then factory scale.Still through the study of non-dimensional groups,it is easy to calculate economies of scale embedded in the production process.Synergy savings and target economies cause economies of scale in a production process and reduce the cost of production per unit of output when production is increased.Non-dimensional groups can be a quantitative and measurable indicator for calculating and predicting economies of scale in an industrial unit.The same can happen in an economic unit providing services,that is,intangible products.

关键词： dimensional analysis knowledge acquisition dimensionless groups case based reasoning data mining Blake number modified Reynolds number adsorption sedimentation flocculation filtration scale up

Scalar transport by propagation of an internal solitary wave over a slope-shelf

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Journal of Hydrodynamics 2019年第2期31卷 317-325页

作者： Jin Xu Ling-ling Wang Hong-wu Tang Zhu Hai John James Reginald Williams State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hobai UniversityNanjing 210098China College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China School of Engineering and Materials Science Queen Mary University of LondonLondonUK

Internal solitary waves(ISWs)of depression are commonly found in the coastal environment and are believed to re-suspend sediments in coastal regions where the waves break.In this research,the direct numerical simulation is used to study the scalar transport induced by the ISWs of depression propagating over a slope-shelf topography.The scalar in this paper is considered to represent the concentrations of very fine suspended solids or pollutants.Vortices are observed from the numerical results at the bottom boundary layer on the slope during the ISW shoaling process,resulting in a scalar transport.All in cident ISWs of depression are observed to produce a waveform inversion on the shelf.The scalar transport from a slope to a shelf is the consequence of the combined vortices at the bottom boundary layer and the overturning of the ISWs of depression,and the latter was commonly ignored in previous studies.This study shows that the ISW-induced scalar transport consists of the following four stages:the slip transport,the wash transport,the vortex transport,and the secondary transport.A dimensionless time scales of the four stages are calculated,and the beginning times of the wash transport and the secondary transport are found to be uncorrelated with the slope gradients,taking values of 1.26,4,respectively.

关键词： Internal solitary waves slope-shelf scalar transport wave inversion dimensionless time scale

Trends on physical understanding of bioink printability

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Bio-Design and Manufacturing 2019年第1期2卷 50-54页

作者： Jun Yin Dengke Zhao Jingyi Liu The State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou 310028 China Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province School of Mechanical Engineering. Zhejiang University Hangzhou 310028. China

Recently, 3D bioprinting is developed as an emerging approach, increasingly applied to materials for healthcare;while, the precise placement of cells and materials, and the shape fidelity of forming constructs is of great importance for successful application of 3D bioprinting. Research efforts have been made to develop new bioinks as "raw materials" with better biocompatibility and biofunctionality, but the printability of bioinks is largely ignored and still needs to be carefully examined to enable robotic bioprinting. This article aims to introduce a recent published review (Appl. Phys. Rev. 2018, 5, 041304) on the evaluation of bioink printability by Huang's research group from University of Florida. Huang et al. comprehensively reviewed the bioink printability based on the physical point of view during inkjet printing, laser printing, and microextrusion, and a series of self-consistent time scales and dimensi on less quantities were utilized to physically understand and evaluate bioink printability. This article would be helpful to know the trends on physical understanding of bioink printability.

关键词： Bioink 3D bioprinting Printability Timescale dimensionless numbers Phase diagram

Estimation of J—R Curves for Small-Sized COEC Specimens and Its Application Considering Crack-Tip Cons tr aints

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Acta Mechanica Solida Sinica 2019年第3期32卷 261-276页

作者： G.W.He C.Bao L.X.Cai Y.J.Wu Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 China

The normalization method has been employed to estimate the J-resistance (J—R) curves for C-shaped outside edge-notched compression (COEC) specimens of SA-508 steel. The COEC specimens present the lowest J—R curves in comparison with other three types of specimens. Based on the J—Q—M met hod, the constraint parame ter Q determined at the mid-plane in the through-thickness direction of the specimen is used to approximately quantify the threedimensional crack-tip constraint for COEC specimens. Combining with the previous experiments on J—R curves, the constraint-coirected J—R curves for SA-508 steel specimens are given, which may be used to predict the fracture toughness of actual cracked components in structural integrity assessment.

关键词： Ductile fracture toughness COEC specimen dimensionless load separation principle Normalization method Crack-tip constraint J-Q-M method

Experimental study on pressure and temperature distributions for low mass flux steam jet in subcooled water

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Science China(Technological Sciences) 2009年第6期52卷 1493-1501页

作者： JunJie Yan XinZhuang Wu DaoTong Chong State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

A low mass flux steam jet in subcooled water was experimentally investigated.The transition of flow pattern from stable jet to condensation oscillation was observed at relatively high water temperature.The axial total pressures,the axial and radial temperature distributions were measured in the jet region.The results indicated that the pressure and temperature distributions were mainly influenced by the water temperature.The correlations corrected with water temperature were given to predict the dimen-sionless axial pressure peak distance and axial temperature distributions in the jet region,the results showed a good agreement between the predictions and experiments.Moreover,the self-similarity property of the radial temperature was obtained,which agreed well with Gauss distribution.In present work,all the dimensionless properties were mainly dependent on the water temperature but weakly on the nozzle size under a certain steam mass flux.

关键词： dimensionless self-similarity steam jet condensation temperature distribution total pressure

Study on Flow Characteristics of a Turbulent Boundary Layer and Vortex Structure of High Pressure Guide Vanes in SCO_2 Turbines

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Journal of Thermal Science 2019年第3期28卷 571-584页

作者： HAN Wanlong WANG Yueming FENG Zhenping LI Hongzhi YAO Mingyu ZHANG Yifan R&D Center Xi'an Thermal Power Research Institute Co. Ltd. School of Energy and Power Engineering Xi'an Jiaotong University

In order to further understand the aerothermodynamic performance and flow loss mechanism of SCO_2 turbines, RANS equations and an SST Turbulence Model were chosen for a numerical study on the secondary flow and vortex structure of cascades using the commercial software CFX. The dimensionless vorticity analysis method was used to study the flow characteristics of the logarithmic layer and viscous sublayer in high pressure guide vane cascades. The new vortex structure and formation mechanism of the vortices were given and analyzed. Simulation results indicated that during the motion of the boundary layer in the cascades, the logarithmic layer and viscous sublayer obtain the different rotational direction vorticity, respectively. The endwall logarithmic layer and pressure side leg of the horseshoe votex gradually develop into the passage vortex, with the endwall viscous sublayer gradually developing into the corner viscous sublayer vortex II and the endwall viscous sublayer vortex I. The endwall viscous sublayer that rolled by the passage vortex is encountered with the upstream-side and radial boundary layer of the vane at the suction separation line, forming the suction separation line vortex beside the passage vortex. A pair of radial transition vortices are formed between the wake and the main stream.

关键词： SCO2 turbine vortex structure dimensionless vorticity logarithmic layer viscous sublayer secondary flow

NON-SYMMETRICAL PROBLEM OF CIRCULAR THIN PLATES

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Chinese Science Bulletin 1989年第1期34卷 83-85页

作者：王新志王林祥徐鉴 Fundamental Course Department Gansu University of Technology Lanzhou

The general dimensionless equations of large deflection of circular thin plates

关键词： circular dimensionless deflection shells restricted 二甲 expand letter slide 公名

A MATHEMATICAL MODEL FOR OXYGEN TRANSFER IN FLAT PLATE MEMBRANE OXYGENATOR

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Chinese Journal of Chemical Engineering 1989年第2期 147-161页

作者：姜志恒唐寅南包锦明江体乾 Dept. of Chem. Eng. Shandong Polytechnic College East China Institute of Chemical Technology Shanghai

Mass transfer in a flat plate membrane oxygenator was studied and a convective mass transfer modelfor instantaeous reversible oxygenation of Cassonian fluid was presented. Numerical solution of the model canbe obtaine... 详细信息

关键词： reversible Newtonian convective oxygenation unsteady inlet cylinder dimensionless Membrane slightly