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numerical analysis and centrifugal modeling of LnAPLs transport in subsurface system

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Progress in natural Science:Materials international 2006年第4期16卷 416-424页

作者： LO i.M.C. MEEGODA J.n. Department of Civil Engineering Hong Kong University of Science and Technology Hong Kong SARChina Department of Civil and Environmental Engineering new Jersey institute of Technology USA

The transport of non-aqueous phase liquids (nAPLs) in unsaturated soils and groundwater is an important research topic in geo-environmental engineering. in this paper, the mechanism of light nAPLs (LnAPLs) transport in subsurface system is briefly introduced, and the mass transport equations, fluid flow equations, and the constitutive model of relative permeability - saturation - capillary pressure are discussed. Then the numerical method is introduced to simulate the multiphase flow problems in porous media, and the tempospatial distribution of LnAPLs is obtained. Moreover, different boundary conditions are employed in numerical simulation to investigate its effect on transport behavior. To verify the numerical data, centrifugal tests are conducted to model the LnAPLs migration in unsaturated soils and groundwater. The calculation results are agreeable with the experimental findings of centrifugal modeling, which indicates that LnAPLs from leaking point move downwards due to gravity force, and form a high concentration zone above the capillary fringe, and then spread out laterally along the groundwater table. Some LnAPL enters groundwater system to further migrate. The combination of numerical simulation and centrifuge modeling can be a useful means to study the transport behavior of LnAPLs in subsurface system.

关键词： geo-environmental engineering subsurface contamination multiphase flow light non-aqueous phase liquids (LnAPLs) centrifugal modeling technique numerical simulation.

Dirac operator on the sphere with attached wires

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Chinese Physics B 2016年第4期25卷 335-338页

作者： E n Grishanov D A Eremin D A ivanov i Yu Popov Ogarev Mordovia State University Bolshevistskaya Str. 68 Saransk Russia iTMO University Kroverkskiy pr. 49 St. Petersburg 197101 Russia

An explicitly solvable model for tunnelling of relativistic spinless particles through a sphere is suggested. The model operator is constructed by an operator extensions theory method from the orthogonal sum of the Dirac operators on a semi- axis and on the sphere. The transmission coefficient is obtained. The dependence of the transmission coefficient on the particle energy has a resonant character. One observes pairs of the Breit-Wigner and the Fano resonances. it correlates with the corresponding results for a non-relativistic particle.

关键词： Dirac operator nanostructure tunnelling solvable model

Calculation of multicentre nuclear attraction integrals over Slater-type orbitals using unsymmetrical one-range addition theorems

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Chinese Physics B 2010年第4期19卷 180-184页

作者： israfil i.Guseinov n.Seckin Gorgun nimet Zaim Department of Physics Faculty of Arts and SciencesOnsekiz Mart UniversityC anakkaleTurkey Department of Physics Faculty of Arts and SciencesTrakya UniversityEdirneTurkey

Using the unsymmetrical one-range addition theorems introduced by one of the authors with the help of complete orthonormal sets of $／varPsi ^／alpha $-exponential type orbitals （$／alpha = 1,0, - 1, - 2,...）$, this paper presents the sets of series expansion relations for multicentre nuclear attraction integrals over Slater-type orbitals arising in Hartree--Fock--Roothaan equations for molecules. The final results are expressed through multicentre charge density expansion coefficients and basic integrals. The convergence of the series is tested by calculating concrete cases for arbitrary values of parameters of orbitals.

关键词： Slater-type orbitals nuclear attraction integrals Hartree-Fock Roothaan equations unsymmetrical one-range addition theorems

Dielectric tunability of magnetic properties in orthorhombic ferromagnetic monolayer CrSBr

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npj Computational Materials 2023年第1期9卷 1514-1523页

作者： Alexander n.Rudenko Malte Rösner Mikhail i.Katsnelson Radboud University Institute for Molecules and MaterialsHeijendaalseweg 1356525AJ NijmegenThe Netherlands

Monolayer CrSBr is a recently discovered semiconducting spin-3/2 ferromagnet with a Curie temperature of around 146 *** contrast to many other known 2D magnets,the orthorhombic lattice of CrSBr gives rise to spatial anisotropy of magnetic excitations within the 2D *** magnetic anisotropy and considerable magnetic dipolar interactions in CrSBr challenge its theoretical description in terms of spin ***,we employ a Green’s function formalism combined with first-principles calculations to study the magnetic properties of monolayer CrSBr in different regimes of surrounding dielectric *** the free-standing limit,the system is close to an easy-plane magnet,whose long-range ordering is partially *** the contrary,in the regime of large external screening,monolayer CrSBr behaves like an easy-axis ferromagnet with more stable magnetic *** findings suggest that anisotropic layered magnets form a potentially promising platform for studying the effects of substrate screening on magnetic ordering in 2D.

关键词： monolayer orthorhombic anisotropy

Thermogravimetric kinetic analysis of nannochloropsis oculata combustion in air atmosphere

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Frontiers in Energy 2015年第2期9卷 125-133页

作者： SUKARni SUDJiTO nurkholis HAMiDi i.n.G. WARDAnA Uun YAnUHAR Department of Mechanical Engineering Faculty of Engineering StateUniversity of Malang J1. Semarang 5 Malang 65145 East-JavaIndonesia Department of Mechanical Engineering Faculty of EngineeringUniversity of Brawijaya J1. Mayjen Haryono 167 Malang 65145East-Java Indonesia Biotechnology Laboratory Department of Water Resources Manage-ment Faculty of Fisheries and Marine Sciences University ofBrawijaya J1. Veteran Malang 65145 East-Java Indonesia

The thermal behavior of nannochloropsis oculata combustion in air atmosphere were investigated by performing experiments on STA PT1600 Thermal Analyzer at heating rates of 10℃/min, 40℃/min and 70℃/min and range of temperatures from room tempera- ture to 1200℃. The kinetic parameters were evaluated by using Kissinger and Ozawa methods. The result showed that nannochloropsis oculata combustion occurred in five stages. Started with initial devolatilization, the main thermal decomposition and combustion process, transition stage, the combustion of char and the last stage was the slow burning reaction of residual char. in line with increasing heating rate, the mass loss rate increased as well, but it delayed the thermal decomposition processes toward higher temperatures. The average activation energy at the main thermal decomposition stage and the stage of char combustion were approximately 251 kJ/mol and 178 kJ/mol, respectively.

关键词： nannochloropsis oculata combustion,kinetic parameters air atmosphere thermogravimetric

Synthesis,structure and magnetic properties of Sm_(1.2)Ho_(0.8)Fe_(17)Hx(X=0;4.4)

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Journal of Rare Earths 2021年第9期39卷 1089-1094页

作者： S.V.Veselova M.A.Paukov i.S.Tereshina V.n.Verbetsky K.V.Zakharov D.i.Gorbunov A.n.VasiPev Faculty of Physics M.V.Lomonosov Moscow State UniversityMoscow 119991Russia nuclear Fuel Cycle Department.Centrum Vyzkumu Rez Hlavni 130Husinec-Rez 25068.Czech Republic immanuel Kant Baltic Federal University Kaliningrad 236004Russia Faculty of Mathematics and Physics Charles UniversityPrague 12116Czech Republic Hochfeld-Magnetlabor Dresden(HLD-EMFL) Helmholtz-Zentrum Dresden-RossendorfDresden 07328Germany f National Research South Ural State UniversityChelyabinsk 454080Russia

intermetallic compounds based on rare-earth metals and iron are by far the most promising materials for permanent mag *** this work,the multicomponent compound Sm_(1.2)Ho_(0.8)Fe_(17)was prepared by in duction *** hydride Sm_(1.2)Ho_(0.8)Fe_(17)H_(4.4)with a high hydrogen content was obtained by direct hydrogenation of the intermetallic *** rhombohedral Th2Zn17-type of structure(space group R3^(-)m)is inhere nt to parent compound and hydride as *** effect of hydrogenation on the magneric properties of Sm_(1.2)Ho_(0.8)Fe_(17)was *** temperature of the hydride Sm_(1.2)Ho_(0.8)-Fe_(17)H_(4.4)is higher than that of parent compound by△Tc=138 *** hydrogen embedded in Sm_(1.2)Ho_(0.8)Fe_(17)crystal lattice in creases the saturation magnetization(σs)at T=300 K,but does not significantly affect%at T=4.2 *** ferrimagnetic structure is retained in magnetic fields up to 58 T in the parent compound,while,in the hydride,there is a spin-reorie ntatio n phase transitio n observed at 55 *** is found that the parameter of the in tersublattice exchange interaction decreases significantly in the hydride Sm_(1.2)Ho_(0.8)Fe_(17)Hg_(4.4)(and in the nitride Sm_(1.2)Ho_(0.8)Fe_(17)n_(2.4))which is associated with boosting of the unit-cell volume and distances between magnetic ions.

关键词： intermetallic compound Hydride Crystal structure Magnetization Magnetic phase transition Exchange interaction

impact of anisotropic slip on the stagnation-point flow past a stretching/shrinking surface of the Al2O3-Cu/H2O hybrid nanofluid

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Applied Mathematics and Mechanics(English Edition) 2020年第9期41卷 1401-1416页

作者： n.A.ZAinAL R.nAZAR K.nAGAnTHRAn i.POP Department of Mathematical Sciences Faculty of Science and TechnologyUniversiti Kebangsaan MalaysiaUKM Bangi 43600SelangorMalaysia Fakulti Teknologi Kejuruteraan Mekanikal dan Pembuatan Universiti Teknikal Malaysia MelakaDurian Tunggal 76100MelakaMalaysia Department of Mathematics Babes-Bolyai UniversityCluj-Napoca 400084Romania

The characteristics of heat transfer in the three-dimensional stagnationpoint flow past a stretching/shrinking surface of the Al2O3-Cu/H2O hybrid nanofluid with anisotropic slip are *** partial differential equations are converted into a system of ordinary differential equations by valid similarity *** simplified mathematical model is solved computationally by the bvp4c approach in the MATLAB operating *** solving method is capable of generating more than one solutions when suitable initial guesses are *** results are proven to have dual solutions,which consequently lead to the application of a stability analysis that verifies the achievability of the first *** findings reveal infinite values of the dual solutions at several measured parameters causing the non-appearance of the turning points and the critical *** skin friction increases with the addition of nanoparticles,while the escalation of the anisotropic slip effect causes a reduction in the heat transfer rate.

关键词： anisotropic slip three-dimensional flow stagnation-point hybrid nanofluid

Asymptotics for filtration of polydisperse suspension with small impurities

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Applied Mathematics and Mechanics(English Edition) 2021年第1期42卷 109-126页

作者： L.i.KUZMinA Y.V.OSiPOV T.n.GORBUnOVA Department of Applied Mathematics National Research University Higher School of EconomicsMoscow 101000Russia Department of Applied Mathematics Moscow State University of Civil Engineering(National Research University)Moscow 129337Russia

A model for deep bed filtration of a polydisperse suspension with small impurities in a porous medium is *** suspended particles move with the same velocity as the carrier water and get blocked in the pore throats due to the size-exclusion mechanism of particle retention.A solution of the model in the form of a traveling wave is *** global exact solution for a multiparticle filtration with one high concentration and several low concentrations of suspended particles is obtained in an explicit *** analytic solutions for a bidisperse suspension with large and small particles are *** profiles of the retained small particles change monotony with *** global asymptotics for the filtration of a polydisperse suspension with small kinetic rates is constructed in the whole filtration zone.

关键词： deep bed filtration suspension colloid porous medium particle size distribution analytical model

Slip effects on unsteady mixed convection of hybrid nanofluid flow near the stagnation point

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Applied Mathematics and Mechanics(English Edition) 2022年第4期43卷 547-556页

作者： n.A.ZAinAL R.nAZAR K.nAGAnTHRAn i.POP Department of Mathematical Sciences Faculty of Science and TechnologyUniversiti Kebangsaan MalaysiaBangi 43600Malaysia Fakulti Teknologi Kejuruteraan Mekanikal dan Pembuatan Universiti Teknikal Malaysia MelakaHang Tuah JayaDurian Tunggal 76100Malaysia institute of Mathematical Sciences Faculty of ScienceUniversiti MalayaKuala Lumpur 50603Malaysia Center for Data Analytics Consultancy and ServicesFaculty of ScienceUniversiti MalayaKuala Lumpur 50603Malaysia Department of Mathematics Babes-Bolyai UniversityR-400084 Cluj-NapocaRomania

The unsteady mixed convection of the Al_(2)O_(3)-Cu/H_(2)O hybrid nanofluid flow near the stagnation point past a vertical plate is *** bvp4c technique is used to solve the resulting ordinary differential *** combined effects of the velocity and thermal slip are *** effects of different relevant physical parameters are studied *** results show that the heat transfer rate is reduced when the volume fraction of the nanoparticles increases,while the unsteadiness parameter has an opposite effect in the opposing *** presence of the slip parameter is proven to increase the skin friction coefficient while reduce the local nusselt number in the buoyancy opposing flow.A contradictory result is observed in the buoyancy assisting ***,the heat transfer rate is reduced in the buoyancy of the assisting and opposing flows when the thermal slip effect is considered.

关键词： hybrid nanofluid mixed convection unsteady flow stagnation point