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Discriminated Dimensional Analysis Versus classical Dimensional Analysis and Applications to Heat Transfer and Fluid Dynamics

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chinese Journal of chemical Engineering 2007年第5期15卷 626-631页

作者： F. Alhama c.N. Madrid Department of Applied Physics Technical University of Cartagena Campus Muralla del Mar Cartagena 30203 Spain

In contrast to classical dimensional analysis, discriminated dimensional analysis assumes that spatial coordinates are dimensionally independent of each other and allows other types of geometrical quantity to be used in the dimensional basis, such as surfaces and angles. As a consequence, discriminated dimensional analysis leads to a lower number of dimensional groups, which makes the solution more precise. Besides, these discriminated groups have a clear physical meaning in terms of force and energy balances. The paper introduces this technique and provides dimensional equations for the main quantities and physical parameters of the heat transfer and fluid flow fields. Two applications are presented to demonstrate the efficiency of this method.

关键词： discriminated dimensional analysis heat transfer fluid dynamics dimensionless number

Pinless Friction Stir Spot Welding of Mg-3Al-1Zn Alloy with Zn Interlayer

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Journal of Materials Science & Technology 2016年第1期32卷 76-88页

作者： R.Z.Xu D.R.Ni Q.Yang c.Z.Liu Z.Y.Ma college of Materials Science and Engineering Shenyang Aerospace University Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

With the addition of a thin Zn interlayer, 2.4 mm thick Mg-3AI-1Zn alloy sheets were friction stir spot welded （FSSW） using a pinless tool with fiat, convex and concave shoulder shapes. The results showed that an alloying reaction took place between the Mg substrate and Zn interlayer during FSSW, forming a discontinuous intermetallics layer composed of dispersive （α-Mg ＋ MgZn） eutectic structure under- neath the shoulder and a Mg-Zn intermetallics bonding zone at the outside of the joints. This alloying reaction increased the bonded area and eliminated the hook defects, thereby producing sound FSSWjoints with a shallow keyhole without hook defects. The increase of plunge depth was beneficial to the Mg-Zn diffusion, thereby increasing the tensile-shear load of the joints. However, excessive plunge depths re- sulted in a decrease of the effective sheet thickness, reducing the strength of the joints. At a small plunge depth, the convex and concave shoulders were more beneficial to the interface reaction than the fiat shoul- der. The maximum joint load of 6.6 kN was achieved by using the concave shoulder at a plunge depth of 1.0 mm. A post-welding heat treatment promoted the dissolution of the discontinuous reaction layer in the joints; however, it led to the occurrence of void defects, influencing the bonding strength.

关键词： Friction stir spot welding Magnesium alloys Zn interlayer Hook defects

Time-Independent Finite Difference and Ghost cell Method to Study Sloshing Liquid in 2D and 3D Tanks with Internal Structures

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communications in computational Physics 2013年第3期13卷 780-800页

作者： c.H.Wu O.M.Faltinsen B.F.chen Department of Marine Environment and Engineering National Sun Yat-Sen UniversityKaohsiung 804Taiwan certre for Ships and Ocean Structures&Department of Marine Technology NTNUTrondheim 7491Norway

A finite difference scheme with ghost cell technique is used to study viscous fluid sloshing in 2D and 3D tanks with internal *** Navier-Stokes equations in a moving coordinate system are derived and they are mapped onto a time-independent and stretched *** staggered grid is used and the revised SIMPLEc iteration algorithm is *** developed numerical model is rigorously validated by extensive comparisons with reported analytical,numerical and experimental *** present numerical results were also validated through an experiment setup with a tank excited by an inclined horizontal excitation or a tank mounted by a vertical *** method is then applied to a number of problems including sloshing fluid in a 2D tank with a bottom-mounted baffle and in a 3D tank with a vertical *** phenomena of diagonal sloshing waves affected by a vertical plate are investigated in detail in this *** effects of internal structures on the resonant frequency of a tank with liquid are discussed and the present developed numerical method can successfully analyze the sloshing phenomenon in 2D or 3D tanks with internal structures.

关键词： Liquid sloshing baffle plate time-independent finite difference ghost cell

Effect of processing and accelerated storage on the volatile composition and sensory profile of a tomato soup

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Food Quality and Safety 2022年第2期6卷 341-352页

作者： Lena c.Strohla Krishnachandra S.Hidangmayum Sandra S.Waehrens Vibeke Orlien Mikael A.Petersen Department of Food Science University of Copenhagen1958 Frederiksberg CDenmark

The volatile and sensory profile of pasteurized(95℃,18 min)and sterilized(120℃,14 min)tomato soup and its changes at accelerated storage conditions(37℃and 42℃)were identified,characterized,and correlated by predictive *** led to more profound changes over storage compared to pasteurisation,showing enhanced levels of‘dark'odour,‘burnt'flavour,and‘complexity',while pasteurized soup had more pronounced‘green'odour,‘vegetables'flavour,‘harmony',and‘freshness'.Over time,‘dark'and‘burnt'significantly increased for sterilized soups,whereas‘green'decreased significantly only for sterilized soup stored at 42℃.The changes of‘dark',‘green',‘off-flavour,‘burnt',‘har mony',and‘freshness'were associated with formation of furans(furfural and 2-acetyl-5-methylfuran),and decline of unsaturated aldehydes like E-2-octenal and E,E-2,*** compounds were identified to represent potential shelf-life markers,yet more studies on their odour activity in the tomato soup matrix are necessary to understand their contribution to the sensory *** construction of partial least squares models allowed the prediction of‘green',‘off-flavour',‘burnt',and‘freshness'based on selected *** models will be important tools in the process of predicting the end of shelf life,but need to be supplemented with consumer acceptability levels.

关键词： Volatile composition sensory profile accelerated storage tomato soup shelf life prediction partial least dquares regression

Symmetry-aware recursive image similarity exploration for materials microscopy

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npj computational Materials 2021年第1期7卷 1508-1521页

作者： Tri N.M.Nguyen Yichen Guo Shuyu Qin Kylie S.Frew Ruijuan Xu Joshua c.Agar Department of Materials Science and Engineering Lehigh UniversityBethlehemPA 18015USA Department of computer Science and Engineering Lehigh UniversityBethlehemPA 18015USA Department of Mechanical Engineering Lehigh UniversityBethlehemPA 18015USA Department of Applied Physics Stanford UniversityStanfordCA 94305USA

In pursuit of scientific discovery,vast collections of unstructured structural and functional images are acquired;however,only an infinitesimally small fraction of this data is rigorously analyzed,with an even smaller fraction ever being *** method to accelerate scientific discovery is to extract more insight from costly scientific experiments already ***,data from scientific experiments tend only to be accessible by the originator who knows the experiments and ***,there are no robust methods to search unstructured databases of images to deduce correlations and ***,we develop a machine learning approach to create image similarity projections to search unstructured image *** improve these projections,we develop and train a model to include symmetry-aware *** an exemplar,we use a set of 25,133 piezoresponse force microscopy images collected on diverse materials systems over five *** demonstrate how this tool can be used for interactive recursive image searching and exploration,highlighting structural similarities at various length *** tool justifies continued investment in federated scientific databases with standardized metadata schemas where the combination of filtering and recursive interactive searching can uncover synthesis-structure-property *** provide a customizable open-source package(https://***/m3-learning/Recursive_Symmetry_Aware_Materials_Microstructure_Explorer)of this interactive tool for researchers to use with their data.

关键词： interactive image similarity

A Quantitative Analysis of Mn Segregation at Partitioned Ferrite/Austenite Interface in a Fe-c-Mn-Si Alloy

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Journal of Materials Science & Technology 2009年第3期25卷 383-388页

作者： H. Guo S.W. Yang c.J.Shang X.M. Wang X.L. He Department of Materials Physics and chemistry University of Science and Technology Beijing Beijing 100083 China

Mn segregation at austenite/ferrite interface is studied in a Fe-c-Mn-Si alloy held at 656℃. Mn is partitioned during the growth of ferrite and as a result, a Mn pile-up exists in front of interface on the matrix side. An approach to evaluate Mn segregation quantitatively is developed by combining STEM raster window scanning and simulation of the interaction of the electron beam with the sample to subtract the contribution of Mn pile-up and obtain pure Mn segregation value. The evaluated maximum Mn interfacial segregation is in the order of a half-monolayer.

关键词： Interfacial segregation Phase transformation STEM Beam broadening

Effect of Icosahedral Phase on crystallographic Texture and Mechanical Anisotropy of Mg–4%Li Based Alloys

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Journal of Materials Science & Technology 2017年第5期33卷 475-480页

作者： c.Q.Li D.K.Xu S.Yu L.Y.Sheng E.H.Han School of Materials Science and Engineering Northeastern University cAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering Shenyang Aerospace University Shenzhen Institute Peking University Shenzhen Key Lab Human Tissue Regenerate & Repair

Through investigating and comparing the microstructure and mechanical properties of the as-extruded Mg alloys Mg-4%Li and Mg-4%Li-6%Zn-l.2%Y （in wt%）, it demonstrates that although the formation of I-phase （Mg3Zn6Y, icosahedral structure） could weaken the crystallographic texture and improve the me- chanical strength, the mechanical anisotropy in terms of strength remains in Mg-4%Li-6%Zn-1.2%Y alloy. Failure analysis indicates that for the Mg-4%Li alloy, the fracture surfaces of the tensile samples tested along transverse direction （TD） contain a large number of plastic dimples, whereas the fracture surface exhibits quasi-cleavage characteristic when tensile samples were tested along extrusion direction （ED）. For the Mg-4%Li-6%Zn-I.2%Y alloy, typical ductile fracture surfaces can be observed in both ＂TD＂ and ＂ED＂ samples. Moreover, due to the zonal distribution of broken l-phase particles, the fracture surface of ＂TD＂ samples is characterized by the typical ＂woody fracture＂.

关键词： Mg-Li alloy Texture Mechanical anisotropy Fracture

Nanostructured steels for advanced structural applications

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Materials Futures 2022年第1期1卷 97-100页

作者： H J Kong T Yang T L Zhang B X cao c T Liu Department of Mechanical Engineering Department of Material Science and EngineeringHong Kong Institute for Advanced StudyCity University of Hong KongHong KongPeople’s Republic of China

This vision summarizes the recent advancement of nanostructured steels foradvanced structural applications, foresees possible challenges and pinpoints futuredirections as well as opportunities in this new era of indus... 详细信息

关键词： nanostructured steels extreme environments advanced manufacturing shape memory

On a class of Solitary Wave Solutions of Atmospheric Nonlinear Equations

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Advances in Atmospheric Sciences 1991年第3期8卷 357-362页

作者： R. Dhar c. Guha-Roy D. K. Sinha Permanent address: S. A. Jaipuria college 10 Raja Nabakrishna Street Calcutta-700005 INDIADepartment of Mathematics Jadavpur University Calcutta-700032 IndiaCentre for atmospheric Sciences University of Calcutta 92 A. P. C. Road Calcutta-700009 INDIA

In this paper, an attempt is made to study some interesting results of the coupled nonlinear equations in the atmosphere. By introducing a phase angle function ζ, it is shown that the atmospheric equations in the pre... 详细信息

关键词： On a class of Solitary Wave Solutions of Atmospheric Nonlinear Equations