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Validation of CFD-DeM model for iron ore reduction at particle level and parametric study

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Particuology 2020年第4期18卷 163-172页

作者： Dianyu e International Research Institute for Minerals Metallurgy and MaterialsJiangxi University of Science and TechnologyNanchang 330013China Department of Chemical engineering Monash UniversityClaytonVIC 3800Australia

Iron ore reduction is a primary unit operation in current metallurgy processes and dominates the energy consumption and greenhouse gas(GHG)emissions of the iron-making process,Therefore,even a slight improvement of the energy efficiency or GHG emissions of iron ore reduction would yield considerable benefits to the cost of pig iron and,more importantly,to mitigation of the associated carbon *** current study presents a discrete model that describes the iron ore reduction process for a single *** transient reaction progress can be predicted and is validated against experimental measurements under various operating conditions,including different reducing gases and *** effects of pressure,isothermality,gas composition,and flow rate on reduction are *** reduction rate increases significantly with increasing pressure until 5 atm,and the entire reduction process occurs more slowly under non-isothermal conditions than under isothermal *** work provides a solid foundation for the development of a comprehensive particulate system model that considers both heat and mass transfer.

关键词： Iron ore reduction Chemical reaction Blast furnace Discrete element method Computational fluid dynamics

Thermal conductivity of systems with a gap in the phonon spectrum

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Chinese Physics B 2018年第7期27卷 424-430页

作者： e Salamatov Udmurt Federal Research Center Ural Branch of the Russian Academy of Sciences

An original theoretical model for describing the low-temperature thermal conductivity in systems with a region of forbidden values （a gap） in the phonon spectrum is proposed. The model is based on new experimental results on the temperature dependence of the phonon diffusion coefficient in nanoceramics and dielectric glasses which showed a similar anomalous behavior of the diffusion coefficient in these systems that may be described under the assumption of a gap in the phonon spectrum. In this paper, the role of the gap in low-temperature behavior of the thermal conductivity, ~＇（T）, is analyzed. The plateau in the temperature dependence of the thermal conductivity is shown to correlate with the position and the width of the gap. The temperature dependence of thermal conductivity of such systems when changing the scat- tering parameters related to various mechanisms is studied. It is found that the umklapp process （U-processes） involving low-frequency short-wavelength phonons below the gap forms the behavior of the temperature dependence of thermal con- ductivity in the plateau region. A comparison of the calculated and experimental results shows considerable possibilities of the model in describing the low-temperature thermal conductivity in glass-like systems.

关键词： phononic band gap phonon diffusion coefficient thermal conductivity glassy crystals

Magnetophotothermal interaction in a rotating solid cylinder of semiconductor silicone material with time dependent heat flow

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Applied Mathematics and Mechanics(english edition) 2021年第1期42卷 39-52页

作者： A.e.ABOUeLReGAL Department of Mathematics College of Science and ArtsJouf UniversityAl-Qurayyat 77423Saudi Arabia Department of Mathematics Faculty of ScienceMansoura UniversityMansoura 35516Egypt

A mathematical model linking thermoelasticity to photothermal experiments is proposed with the consideration of the photothermal *** system equations for coupled plasma,heat conduction with phase-lags(PLs),and motion equations are introduced and solved by using the Laplace transform *** photothermal,thermal,and elastic waves in a rotating solid cylinder of semiconductor material are analyzed with the proposed *** cylinder surface is constrained and subjected to a time-dependent pulse heat *** sensitivity of the physical fields for the angular velocity,PLs,and thermal vibration parameters is *** addition,the effects of the effective parameters on the physical quantities are graphically illustrated and discussed in detail.

关键词： photothermal phase-lag(PL) solid cylinder rotation semiconductor carrier concentration

Size-dependent thermoelastic initially stressed micro-beam due to a varying temperature in the light of the modified couple stress theory

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Applied Mathematics and Mechanics(english edition) 2020年第12期41卷 1805-1820页

The bending of the euler-Bernoulli micro-beam has been extensively modeled based on the modified couple stress(MCS)*** many models have been incorporated into the literature,there is still room for introducing an improved model in this *** this work,we investigate the thermoelastic vibration of a micro-beam exposed to a varying temperature due to the application of the initial stress employing the MCS theory and generalized *** MCS theory is used to investigate the material length scale *** the Laplace transform,the temperature,deflection,displacement,flexure moment,and stress field variables of the micro-beam are *** effects of the temperature pulse and couple stress on the field distributions of the micro-beam are obtained numerically and graphically *** numerical results indicate that the temperature pulse and couple stress have a significant effect on all field variables.

关键词： thermoelectricity micro-beam initial stress temperature pulse modified couple stress(MCS)theory

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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Neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer M.Colón-Mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose M.Santiago Samuel e.Ocasio Rivera Dina P.Bracho-Rincon Luis H.Pagan Rivera Jorge D.Miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA National Institutes of Health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of Neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain eAAT-1/GLAST eAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

Collapse assessment of steel moment frames using endurance time method

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earthquake engineering and engineering Vibration 2015年第2期14卷 347-360页

作者： e.Rahimi H.e.estekanchi Department of Civil engineering Sharif University of Technology (SUT)

In endurance time(eT) method structures are subjected to a set of predesigned intensifying excitations. These excitations are produced in a way that their response spectrum, while complying with a specifi ed spectrum, intensifi es with time so they can be used approximately to simulate the average effects of several ground motions scaled to different intensities. In this paper applicability of the eT method for evaluating collapse potential of buildings is investigated. A set of four steel moment frames is used for collapse assessment. The process of using eT method in collapse evaluation is explained and the results are compared with incremental dynamic analysis(IDA) results. It is shown that although the computational effort using the eT method is much less than the IDA analysis, the results of both methods are consistent. Finally collapse fragility curves using eT and IDA methods are produced and it is shown that the probabilities of collapse in different hazard levels are also consistent.

关键词： endurance time method collapse analysis incrementa

INVeRSe PROBLeMS FOR A GeNeRAL MULTI-CONNeCTeD BOUNDeD DRUM WITH APPLICATIONS IN PHYSICS

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Acta Mathematica Scientia 2003年第1期23卷 104-116页

作者： e.M.e.Zayed Mathematics Department Faculty of Science Zagazig University Zagazig Egypt

This paper studies the influence of a finite container on an ideal *** trace of the heat kernel (t) =exp, where are the eigenvalues of the negative Laplacian -in Rn(n = 2 or 3), is studied for a general multi-connected bounded drum ft which is surrounded by simply connected bounded domains Ωi with smooth boundaries Ωi(i = 1,… ,m) where the Dirichlet, Neumann and Robin boundary conditions on Ωi(i = 1,…,m) are considered. Some geometrical properties of Ω are determined. The thermodynamic quantities for an ideal gas enclosed in Ω are examined by using the asymptotic expansions of (t) for short-time t. It is shown that the ideal gas can not feel the shape of its container Ω, although it can feel some geometrical properties of it.

关键词： Inverse problem heat kernel eigenvalues an ideal gas multi-connected bounded domain

The Asymptotics of the Two-Dimensional Wave equation for a General Multi-Connected Vibrating Membrane with Piecewise Smooth Robin Boundary Conditions

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Acta Mathematica Sinica,english Series 2004年第2期20卷 209-222页

作者： e.M.e.ZAYeD Department of Mathematics Faculty of ScienceZagazig UniversityZagazigEgypt

The asymptotic expansion for small |t| of the trace of the wave kernel , where and are the eigenvalues of the negative Laplacian in the (x 2,x 2)-plane, is studied for a multi-connected vibrating membrane ? in R 2 surrounded by simply connected bounded domains ? j with smooth boundaries ?? j (j = 1, ..., n), where a finite number of piecewise smooth Robin boundary conditions on the piecewise smooth components Γ i (i = 1+k j?1, ..., k j ) of the boundaries ?? j are considered, such that and k 0 = 0. The basic problem is to extract information on the geometry of ? using the wave equation approach. Some geometric quantities of ? (e. g. the area of ?, the total lengths of its boundary, the curvature of its boundary, the number of the holes of ?, etc.) are determined from the asymptotic expansion of the trace of the wave kernel for small |t|.

关键词： Inverse problem Wave kernel eigenvalues Robin boundary conditions Vibrating membrane Hearing the shape of a drum

The 3D Inverse Problem of the Wave equation for a General Multi-connected Vibrating Membrane with a Finite Number of Piecewise Smooth Boundary Conditions

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Acta Mathematica Sinica,english Series 2005年第4期21卷 733-752页

作者： e.M.e.ZAYeD Mathematics Department Faculty of ScienceZagazig UniversityZagazig.Egypt

The trace of the wave kernel μ（t） =∑ω=1^∞ exp（-iteω^1/2）, where {eω}ω^∞=1 are the eigenvalues of the negative Laplacian -△↓2 = -∑k^3=1 （δ/δxk）^2 in the （x^1, x^2, x^3）-space, is studied for a variety of bounded domains, where -∞ 〈 t 〈 ∞ and i= √-1. The dependence of μ （t） on the connectivity of bounded domains and the Dirichlet, Neumann and Robin boundary conditions are analyzed. Particular attention is given for a multi-connected vibrating membrane Ω in Ra surrounded by simply connected bounded domains Ω j with smooth bounding surfaces S j （j = 1,……, n）, where a finite number of piecewise smooth Dirichlet, Neumann and Robin boundary conditions on the piecewise smooth components Si^＊（i = 1 ＋ kj-1,……, kj） of the bounding surfaces S j are considered, such that S j = Ui-1＋kj-1^kj Si^＊, where k0=0. The basic problem is to extract information on the geometry Ω by using the wave equation approach from a complete knowledge of its eigenvalues. Some geometrical quantities of Ω （e.g. the volume, the surface area, the mean curvuture and the Gaussian curvature） are determined from the asymptotic expansion ofexpansion of μ（t） for small │t│.

关键词： Inverse problem Wave kernal eigenvalues Greens function Multi-connected vibrating membrane Negative Laplacian Heat kernel