检索结果-南通市图书馆

A computational study of a capsule lateral migration in microchannel flow

在线全文

学校读者我要写书评

暂无评论

Acta mechanica Sinica 2013年第4期29卷 513-525页

作者： m.Navidbakhsh m.Rezazadeh Department of mechanical Engineering Iran University of Science and Technology

A numerical method is used to model a capsule migration in a microchannel with small Reynolds number Re = 0.01. The capsule is modeled as a liquid drop sur- rounded by a neo-Hookean elastic membrane. The numer- ical model combines immersed boundary with lattice Boltz- mann method （IB-LBm）. The LBm is used to simulate fixed Cartesian grid while the IBm is utilized to implement the fluid-structure interaction by a set of Lagrangian moving grids for the membrane. The effect of shear elasticity and bending stiffness are both considered. The results show the significance of elastic modulus and initial lateral position on deformation and morphological properties of a circular cap- sule. The wall effect becomes stronger as the capsule ini- tial position gets closer to the channel wall. As the elastic modulus of membrane increases, the capsule undergoes less pronounced deformation and velocity in direction x is de- creased, thus, the capsule motion is slower than the back- ground flow. The best agreement between the present model and experiments for migration velocity takes place for the capsule with normal to moderate membrane elastic modulus. The results are in good agreement with experiment study of Coupier et al. and previous numerical studies. Therefore, the IB-LBm can be employed to make prediction in vitro and in vivo studies of capsule deformation.

关键词： Capsule. Lateral migration. Lattice Boltzmann.Immersed boundary ~ Deformation ~ Initial position

Health monitoring of time-varying stochastic structures by latent components and fuzzy expert system

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2008年第1期7卷 91-106页

作者： m. m. Ettefagh m. H. Sadeghi Vibration and modal Analysis Laboratory Department of Mechanical Engineering University of Tabriz Tabriz 51666 Iran

In this paper, a novel parametric model-based decomposition method is proposed for structural health monitoring of time-varying structures. For this purpose, the advanced Functional-Series Time-dependent Auto Regressive moving Average （FS-TARmA） technique is used to estimate the parameters and innovation variance used in the parametric signal decomposition scheme. Additionally, a unique feature extraction and reduction method based on the decomposed signals, known as Latent Components （LCs）, is proposed. To evaluate the efficiency of the proposed method, numerical simulation and an experimental study in the laboratory were conducted on a time-varying structure, where various types of damage were introduced. The Fuzzy Expert System （FES） was used as a classification toot to demonstrate that the proposed method successfully identifies different structural conditions when compared with other methods based on non-reduced and ordinary feature extraction.

关键词： parametric modeling signal decomposition feature extraction/reduction fuzzy classification

Leaching of complex sulphide concentrate in acidic cupric chloride solutions

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2007年第2期17卷 423-428页

作者： m.TCHOUmOU m.ROYNETTE Faculty of Science Marien Ngouabi University Laboratory of Applied Electrochemistry EHICS Louis Pasteur University

The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena >sphalerite>chalcopyrite.

关键词：酸性氯化铜溶液复合硫化物精矿浸出溶出速度

Column leaching of lanthanides from Abu Tartur phosphate ore with kinetic study

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2010年第4期28卷 576-580页

作者： A.T. Kandil m.m. Aly E.m. moussa A.m. Kamel m.m. Gouda m.N. Kouraim Chemistry Department Faculty of Science Helwan University Nuclear materials Authority P.O. Box 530 El Maadi Cairo Egypt

The dynamic leaching of lanthanides from a west desert phosphate ore, Egypt (Abu Tartur) by hydrochloric acid, nitric acid and sulfuric acid solutions was investigated in this study as a function of acid concentration, flow rate and the presence of some additives such as boric acid. Also the kinetics of leaching of lanthanides was investigated as a function of temperature. It was found that the leaching process could be described by a shrinking-core model, with activation energy about 5.9, 13.8 and 21.9 kJ/...

关键词： column leaching lanthanides Abu Tartur hydrochloric acid nitric acid sulfuric acid kinetics rare earths

microstructural evolution during ultra-rapid annealing of severely deformed low-carbon steel: strain, temperature, and heating rate effects

在线全文

学校读者我要写书评

暂无评论

International Journal of minerals,metallurgy and materials 2016年第7期23卷 779-792页

作者： m.A.mostafaei m.Kazeminezhad Department of materials Science and Engineering Sharif University of Technology

An interaction between ferrite recrystallization and austenite transformation in low-carbon steel occurs when recrystallization is delayed until the intercritical temperature range by employing high heating rate. The kinetics of recrystallization and transformation is affected by high heating rate and such an interaction. In this study, different levels of strain are applied to low-carbon steel using a severe plastic deformation method. Then, ultra-rapid annealing is performed at different heating rates of 200–1100°C/s and peak temperatures of near critical temperature. Five regimes are proposed to investigate the effects of heating rate, strain, and temperature on the interaction between recrystallization and transformation. The microstructural evolution of severely deformed low-carbon steel after ultra-rapid annealing is investigated based on the proposed regimes. Regarding the intensity and start temperature of the interaction, different microstructures consisting of ferrite and pearlite/martensite are formed. It is found that when the interaction is strong, the microstructure is refined because of the high kinetics of transformation and recrystallization. moreover, strain shifts an interaction zone to a relatively higher heating rate. Therefore, severely deformed steel should be heated at relatively higher heating rates for it to undergo a strong interaction.

关键词： low-carbon steel annealing microstructural evolution recrystallization phase transformation plastic deformation

The stability of a shearing viscous star with an electromagnetic field

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2013年第5期22卷 175-181页

作者： m. Sharif m. Azama Department of mathematics University of the Punjab Quaid-e-Azam Campus Lahore-54590 Pakistan Division of Science and Technology University of Education Township Campus Lahore-54590 Pakistan

We analyze the role of the electromagnetic field for the stability of a shearing viscous star with spherical symmetry. matching conditions are given for the interior and the exterior metrics. We use a perturbation scheme to construct the collapse equation. The range of instability is explored in Newtonian and post Newtonian （pN） limits. We conclude that the electromagnetic field diminishes the effects of the shearing viscosity in the instability range and makes the system more unstable in both Newtonian and post Newtonian approximations.

关键词： gravitational collapse electromagnetic field instability

Phase diagrams and magnetic properties of the mixed spin-1 and spin-3/2 Ising ferromagnetic thin film: monte Carlo treatment

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第2期28卷 414-419页

作者： B Boughazi m Boughrara m Kerouad Laboratoire Physique des matériaux et modélisation des Systémes(LP2mS) UnitéAssociée au CNRST-URAC:08Faculty of SciencesUniversity Moulay Ismail

Phase diagrams and magnetic properties of the mixed spin-1 and spin-3/2 Ising film with different single-ion anisotropies are investigated, by the use of monte Carlo simulation based on heat bath algorithms. The effects of the crystal-fields and the surface coupling on the phase diagrams are investigated in detail and the obtained phase diagrams are presented. Depending on the Hamiltonian parameters, the system exhibits both second-and first-order phase transitions besides tricritical point, triple point, and isolated critical end point.

关键词： monte Carlo simulation thin film phase diagrams magnetic properties

Thomson effect with hyperbolic two-temperature on magneto-thermo-visco-elasticity

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2021年第9期42卷 1311-1326页

作者： A.m.ALHARBI m.I.A.OTHmAN H.m.ATEF Department of mathematics College of ScienceTaif UniveristyTaif 21944Saudi Arabia Department of mathematics Faculty of ScienceZagazig UniversityZagazig 44519Egypt Department of mathematics Faculty of ScienceDamanhur UniversityDamanhur 22511Egypt

The study considers a homogeneous isotropic thermo-visco-elastic solid with hyperbolic two-temperature to cope up with its two-dimensional(2 D)*** heat conduction equation is influenced by the Thomson ***-Shulman’s theory is used to modify the basic governing equations.A method called"normal mode analysis"is utilized to attain the magnetic field,stress,conductive and thermodynamic temperature,and displacement ***,a number of numerical calculations are performed and discussed to understand the impact of hyperbolic two-temperatures,Thomson parameter,and viscosity on the material mentioned above.

关键词： thermo-visco-elasticity magnetic field hyperbolic two-temperature Lord-Shulman’s theory Thomson coefficient normal mode analysis

Fatigue crack propagation in a helicopter component subjected to impact damage

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第2期17卷 416-428页

作者： m.Fossati m.Pagani m.Giglio A.manes Politecnico di milano Dipartimento di Meccanicavia la Masa 1MilanoItaly

Damage tolerant methodology is increasingly used in aeronautical components,especially due the fact that the Aviation Regulation requires such an assessment in case an accidental damage *** present,there is a strong and actual interest in applying such procedures to helicopter components that are subjected to high frequency cyclic *** this paper,an investigation on a damaged transmission shaft for a tail rotor transmission of an actual helicopter has been carried out focusing on the fatigue crack propagation.A complete sequence of experimental tests was performed in order to create an actual ballistic damage and to subsequently check the damage tolerant *** shaft was damaged by oblique ballistic impact and was subsequently subjected to torsional fatigue *** the fatigue cycles several cracks propagated from the ballistic *** of these steps(impact and fatigue loading)were also simulated by a complex modelling approach based on Finite Element models and fracture mechanics *** comparison between the experimental and numerical results shows a good agreement but it underlines the need for a very refined modelling technique capable to replicate all the features associated with the damage in order to reliably simulate the subsequent propagation phase.

关键词： Ballistic impact Damage Fatigue Crack propagation