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Analytical solution for laminar flow through leaky tube

1991年

作者： michael e.·索莱(m.e. Soule ) B.A.·威尔考克斯(Bruce A. Wilcox)

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Applied mathematics and mechanics(english edition) 2011年第1期32卷 69-74页

作者： m.GORJI m.ALIPANAH m.SHATeRI e.FARNAD Department of mechanical engineering Babol University of Technology Water and Westwater Company

The laminar flow through a leaky tube is investigated, and the momentum and conservation of energy equations are solved analytically. By using the Hagen-Poiseuille velocity profile and defining unknown functions for the axial and radial velocity compo- nents, the pressure and mass transfer equations are obtained, and their profiles are plotted according to different parameters. The results indicate that the axial velocity, the radial velocity, the mass transfer parameter, and the pressure in the tube decrease as the fluid moves along the tube.

关键词： leaky tube permeability mass transfer laminar flow analytical solution

Inflation in Non-de Sitter Background with Coherent States

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Communications in Theoretical Physics 2016年第3期65卷 308-314页

作者： e.Yusofi m.mohsenzadeh m.R.Tanhayi Department of Physics Ayatollah Amoli BranchIslamic Azad University Department of Physics Qom BranchIslamic Azad University Department of Physics Islamic Azad UniversityCentral Tehran Branch

We use the excited coherent states built over the initial non-de Sitter modes,to study the modification of spectra of primordial scalar ***-de Sitter modes are actually the asymptotic solution of the inflaton field equation[*** energy Phys.09（2014） 020].We build excited coherent states over the non-de Sitter modes and despite the Jack of interactions in the Lagrangian,we find a non-zero one-point *** is shown that the primordial non-Gaussianity resulting from.e.cited-de Sitter modes depend both of time and background *** is very tiny of order（≤10^-24）,at the Planck initial fixed time that confirmed by resent observations for single field inflation but it grows in the present ***,our results at the leading order are similar to what obtained with general initial states and in the dS limit leads to standard results[***.1202（2012） 005].We will show that the non-dS modes and its resulting spectrum are more usable for far past time limit.

关键词： inflation initial states planck time background space-time

Use of mesophilic and thermophilic bacteria for the improvement of copper extraction from a low-grade ore

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International Journal of minerals,metallurgy and materials 2011年第2期18卷 138-143页

作者： e.Darezereshki m.Schaffie m.Lotfalian S.A.Seiedbaghery m. Ranjbar Department of mineral Processing engineering Bahonar University energy and environmental engineering Research Center (eeRC) Bahonar University Department of Chemical engineering Bahonar University Industrial mining Research Center (ImRC) Bahonar University Hydrometallurgy Research Unit R & D Center Sarcheshmeh Copper Complex

Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.

关键词： bioleaching mesophilic bacteria thermopilic bacteria copper extraction agglomeration.

Variable fluid properties and thermal radiation effects on flow and heat transfer in micropolar fluid film past moving permeable infinite flat plate with slip velocity

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Applied mathematics and mechanics(english edition) 2012年第5期33卷 663-678页

作者： m.A.A.mAHmOUD S.e.WAHeeD Department of mathematics Faculty of ScienceBenha UniversityBenha 13518Egypt

This work deals with the influence of thermal radiation on the problem of the mixed convection thin film flow and heat transfer of a micropolar fluid past a moving infinite vertical porous flat plate with a slip velocity. The fluid viscosity and the thermal conductivity are assumed to be the functions of tem.e.ature. The equations governing the flow are solved numerically by the Chebyshev spectral method for some representative value of various parameters. In comparison with the previously published work, the excellent agreement is shown. The effects of various parameters on the velocity, the microrotation velocity, and the tem.e.ature profiles, as well as the skin-friction coefficient and the Nusselt num.e., are plotted and discussed.

关键词： micropolar fluid thin film slip velocity variable fluid properties thermalradiation Chebyshev spectral method

melting heat transfer effects on stagnation point flow of micropolar fluid saturated in porous medium with internal heat generation(absorption)

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Applied mathematics and mechanics(english edition) 2014年第8期35卷 979-992页

作者： m.A.A.mAHmOUD S.e.WAHeeD Department of mathematics Faculty of ScienceBenha University 13518BenhaEgypt Department of mathematics and Statistic Faculty of ScienceTaif University 21974TaifKingdom of Saudi Arabia

The effect of melting heat transfer on the two dimensional boundary layer flow of a micropolar fluid near a stagnation point em.e.ded in a porous medium in the presence of internal heat generation/absorption is investigated. The governing non-linear partial differential equations describing the problem are reduced to a system of non-linear ordinary differential equations using similarity transformations solved numerically using the Chebyshev spectral method. Numerical results for velocity, angular velocity and tem.e.ature profiles are shown graphically and discussed for different values of the inverse Darcy num.e., the heat generation/absorption parameter, and the melting parameter. The effects of the pertinent parameters on the local skin-friction coefficient, the wall couple stress, and the local Nusselt num.e. are tabulated and discussed. The results show that the inverse Darcy num.e. has the effect of enhancing both velocity and tem.e.ature and suppressing angular velocity. It is also found that the local skin-friction coefficient decreases, while the local Nusselt num.e. increases as the melting parameter increases.

关键词： melting effect stagnation point micropolar fluid porous medium heat generation (absorption)

Point of Zero Salt effect: Relationships with Clay mineralogy of Representative Soils of the So Paulo State, Brazil

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Pedosphere 2005年第5期15卷 545-553页

作者： m. e. ALVeS A. LAVOReNTI Departamento de Física e Informática Institute de Física de So Carlos-IFSC/USP So Carlos (SP) 13560-970(Brazil). Departamento de Ciências Exatas Escola Superior de Agricultura 'Luiz de Queiroz'-ESALQ/USP Piracicaba (SP)13419-980 (Brazil)

The point of zero salt effect （PZSe） is the soil pH value at which the magnitude of the variable surface charges is not changed due to variations in the ionic concentration of the soil solution. This property influences not only electrochemical phenomena occurring at the solid-solution interface but also the flocculation degree of the soil particles. In this study we investigated the relationships between the clay mineralogy and the PZSe values of representative soils of the Sāo Paulo State, Brazil. The results confirmed the usefulness of the difference between the soil pH values measured in 1 mol L^-1 KCl （pHKCl） and in water （pHH2O）（2 pHKCl-pHH2O） for estimating the PZSe of tropical soils, except for the ones rich in exchangeable Al; furthermore, the ApH index （pHKC1 - pHH2O） was highly correlated with the difference between the PZSe and pHH2O values, reiterating the △pH utility for estimating both the signal and the magnitude of the net surface charge of tropical soils. Finally, correlation and multiple regression analyses showed that the PZSe value of weathered non-allophanic tropical soils tends to increase and to equal the soil pH due to the weathering-induced kaolinite destabilization and concomitant Fe- and Al-oxide accumulation.

关键词： electrochemical properties iron oxides kaolinite tropical soils weathered soils

Photoconductive devices for terahertz pulsed spectroscopy:a review[Invited]

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Photonics Research 2016年第3期4卷 36-42页

作者： e.Castro-Camus m.Alfaro Centro de Investigaciones en Optica A.C. Departamento de matematicas y Fisica Centro de Ciencias BasicasUniversidad Autonoma de Aguascalientes

Photoconductive switches were the key components that allowed the generation and detection of coherent broadband electromagnetic pulses at terahertz frequencies, opening the possibility for performing spectroscopy and,therefore, measuring complex dielectric properties of materials in this band, which was mostly unexplored. In this paper, we present a brief introduction to the operation principles of these devices. Subsequently, we present a review of the current state-of-the-art in this field and discuss the challenges to be faced in future development of these devices.

关键词： As Ga THz Photoconductive devices for terahertz pulsed spectroscopy:a review[Invited

Spontaneous emission Originating from Atomic BeC Interacting with a Single-mode Quantized Field

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Communications in Theoretical Physics 2018年第6期69卷 711-721页

作者： e.Ghasemian m.K.Tavassoly Atomic and molecular Group Faculty of Physics Yazd University

In this paper we present a general theoretical model for the interaction between a num.e. of two-level atoms constituting Bose-einstein condensate （BeG） and a single-mode quantized field. In addition to the usual interacting terms, we take into account interatom as well as higher-order atom-field interactions. To simplify the Hamiltonian of system, after using the Bogoliubov approximation we proceed to calculate the transformed operators of atoms and field. Then, to quantify the spontaneous emission, we get analytical expressions for the expectation value of Jz as the atomic population inversion （API）, in the cases of num.e. and coherent states for the atomic subsystem. Our results show that the above-mentioned model interaction leads to the appearance of collapse-revival phenomenon in API. In more detail, the revival time may be tuned by adjusting the interatom interaction constant. Also, the damping process lowers the amplitude of API, but does not change the CR times for weak damping. moreover, increasing the damping may decrease the num.e. of CRs in a given interval of time such that no revival occurs. Briefly, it may be concluded that in the resonant case the revival times are insensitive to the change of the higher-order atom-field interaction constant and are affected only by the interatom interactions. Finally, we express that, how we can find a practical procedure to measure the quantum states of atoms in BeG.

关键词： Bose-einstein condensate atom-field interaction spontaneous emission atomic population inversion collapse-revival phenomenon

Beyond p-y method:A review of artificial intelligence approaches for predicting lateral capacity of drilled shafts in clayey soils

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Journal of Rock mechanics and Geotechnical engineering 2024年第9期16卷 3812-3840页

作者： m.e.Al-Atroush A.e.Aboelela ezz el-Din Hemdan Civil and environmental engineering Program Engineering Management DepartmentCollege of EngineeringPrince Sultan UniversityRiyadhSaudi Arabia Department of Structural engineering Faculty of EngineeringAin Shams UniversityCairoEgypt Structure and materials Research Lab Prince Sultan UniversityRiyadhSaudi Arabia Computer Science and engineering Department Faculty of Electronic EngineeringMenoufia UniversityMenoufiaEgypt

In 2023,pivotal advancements in artificial intelligence(AI)have significantly *** that in mind,traditional methodologies,notably the p-y approach,have struggled to accurately model the complex,nonlinear soil-structure interactions of laterally loaded large-diameter drilled *** study undertakes a rigorous evaluation of machine learning(mL)and deep learning(DL)techniques,offering a comprehensive review of their application in addressing this geotechnical challenge.A thorough review and comparative analysis have been carried out to investigate various AI models such as artificial neural networks(ANNs),relevance vector machines(RVms),and least squares support vector machines(LSSVms).It was found that despite mL approaches outperforming classic methods in predicting the lateral behavior of piles,their‘black box'nature and reliance only on a data-driven approach made their results showcase statistical robustness rather than clear geotechnical insights,a fact underscored by the mathematical equations derived from these ***,the research identified a gap in the availability of drilled shaft datasets,limiting the extendibility of current findings to large-diameter *** extensive dataset,compiled from a series of lateral loading tests on free-head drilled shaft with varying properties and geometries,was introduced to bridge this *** paper concluded with a direction for future research,proposes the integration of physics-informed neural networks(PINNs),combining data-driven models with fundamental geotechnical principles to improve both the interpretability and predictive accuracy of AI applications in geotechnical engineering,marking a novel contribution to the field.

关键词： Laterally loaded drilled shaft load transfer and failure mechanisms Physics-informed neural networks(PINNs) P-y curves Artificial intelligence(AI) Dataset