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Numerical Modeling of the Solidification Phase Change in a Pipe and Evaluation of the Effect of Boundary Conditions

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Journal of Thermal Science 2010年第5期19卷 419-424页

作者： A.Jalali A.f.Najafi Department of Energy Engineering Power and Water University of Technology

A numerical solution to a two-dimensional model of flow and transient heat transfer involving solidification in a pipe has been *** the temperature of pipe wall is below the freezing point of fluid,phase change of flowing fluid and the influence of different boundary condition,such as pipe wall temperature,initial temperature and inlet velocity has been taken into *** it has been investigated to elicit proper non-dimensional numbers to show the solidification proceeding *** comparing the two acceptable inlet conditions,show distinctions between velocity inlet and pressure inlet boundary condition in such problems,which affect the whole freezing process.

关键词： Phase change Solidification Heat transfer

Projective representation of D_(6)group in twisted bilayer graphene

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Chinese Physics B 2021年第7期30卷 1-4页

作者： Noah f.Q.Yuan Department of Physics Massachusetts Institute of TechnologyCambridgeMassachusetts 02139USA

Within the framework of continuum model,we study the projective representation of emergent D_(6)point group in twisted bilayer *** then construct tight-binding models of the lowest bands without and with external elec... 详细信息

关键词： twisted bilayer graphene tight-binding model projective representation

Impacts of wastewater sludge amendments in restoring nitrogen cycle in p-nitrophenol contaminated soil

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Journal of Environmental Sciences 2011年第4期23卷 616-623页

作者： f. Olcay Topac Sagban Department of Environmental Engineering Uludag University

The possible impacts on nitrogen-cycle in a p-nitrophenol （PNP） polluted soil and the effectiveness of wastewater sludge amendments in restoring nitrification potential and urease activity were evaluated by an incubation study. The results indicated that PNP at 250 mg/kg soil inhibited urease activity, nitrification potential, arginine ammonification rate and heterotrophic bacteria counts to some extents. After exposure to PNP, the nitrification potential of the tested soil was dramatically reduced to zero over a period of 30 days. Based on the findings, nitrification potential was postulated as a simple biochemical indicator for PNP pollution in soils. Nitrogen-cycling processes in soils responded positively to the applications of wastewater sludges. A sludge application rate of 200 tons/ha was sufficient for successful biostimulation of these nitrogen processes. The microbial activities in sludge-amended, heavy PNP-polluted soils seemed to recover after 30–45 days, indicating the effectiveness of sludge as a useful soil amendment.

关键词： p-nitrophenol wastewater sludge soil pollution nitrogen-cycle biostimulation

Antibacterial and anti-parasitic activities of Terfezia claveryi methanolic extract against some common pathogenic agents of infectious diarrhea

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Asian Pacific Journal of Tropical Biomedicine 2022年第5期12卷 216-222页

作者： Sultan f Alnomasy Department of Medical Laboratories Sciences College of Applied Medical SciencesShaqra UniversityAl-Quwayiyah 19257Saudi Arabia

Objective:To assess the antidiarrheal effects of Terfezia claveryi methanolic extract against Escherichia coli,Salmonella typhimurium,Shigella flexneri,and Giardia ***:Antibacterial effects of the Terfezia claveryi methanolic extract were carried out by determining the minimum inhibitory concentration(MIC)and minimum bactericidal concentration through micro broth dilution ***,reactive oxygen species production and protein leakage were *** evaluate the in vitro anti-giardial effects of Terfezia claveryi methanolic extract,Giardia lamblia WB(ATCC®30957)trophozoites were treated with various concentrations of Terfezia claveryi methanolic extract for 10-360 *** addition,the plasma membrane permeability of trophozoites treated with Terfezia claveryi methanolic extract was *** cytotoxicity effects of Terfezia claveryi methanolic extract against normal(HEK293T)and cancer(MCf-7)cells were also assessed using the MTT ***:The MIC and minimum bactericidal concentration of Terfezia claveryi methanolic extract against bacterial strains were in the range of 0.52-1.04 and 1.04-2.08 mg/mL,*** results revealed that reactive oxygen species production and protein leakage were significantly increased after the bacteria were treated with the Terfezia claveryi methanolic extract,especially at 1/3 and 1/2 MICs(Pfurthermore,Terfezia claveryi methanolic extract decreased the viability of Giardia lamblia trophozoites in a dose-dependent *** claveryi methanolic extract at 1,2,and 4 mg/mL resulted in 100%mortality in Giardia lamblia trophozoites after 360,240,and 120 min,***,Terfezia claveryi methanolic extract altered the permeability of plasma membrane of Giardia lamblia trophozoites by increasing the *** assay revealed that the 50%cytotoxic concentrations values for HEK293T and MCf-7 cells were 4.32 mg/mL and 6.40 mg/mL,respectively,indicating that Terfezia clavery

关键词： Terfezia claveryi Shigellosis Giardiasis Herbal medicines Infectious diarrhea Cellular mechanisms Cytotoxicity Microbiology

An Extended Model for Coexistence of Superconductivity and Paramagnetism in High-T_c Superconductors

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Communications in Theoretical Physics 2008年第6期49卷 1631-1634页

作者： f.Inanir Department of Physics Rize UniversityRize53100Turkey

In the present work, the total magnetization in superconducting state is separated into critical state and paramagnetic components in terms of an H（x）-dependent magnetic flux density. Utilizing this model, we reproduce successfully M-H curves measured by Sandu et al. [Phys. Rev. B 74 （2006） 184511] and Sandu et al. [J. Supercond. Incorp. Novel Magn. 17 （2004） 701] for different forms of Jc.

关键词： superconductivity paramagnetism high-Tc superconductor critical-state model

Nonlinear continuous bi-inductance electrical line with dissipative elements:Dynamics of the low frequency modulated waves

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Chinese Physics B 2020年第4期29卷 179-189页

作者： S M Ngounou f B Pelap Unite de Recherche de Mecanique et de Modelisation des Systèmes Physiques(UR-2 MSP) Faculte des SciencesUniversite de DschangBP 69 DschangCameroun Unite de Recherche de Matiere Condensee d'Electronique et de Traitement du Signal(UR-MACETS) Faculte des SciencesUniversite de DschangBP 67 DschangCameroun

The dynamics of modulated waves in a nonlinear bi-inductance transmission line with dissipative elements are *** show the existence of two frequency modes and carry out intensive investigations on the low frequency *** to the multiple scales method,the behavior of these waves is investigated and the dissipative effects are *** appears that the dissipation coefficient increases with the carrier wave *** the continuous approximation,we derive that the propagation of these waves is governed by the complex Ginzburg-Landau equation instead of the Korteweg-de-Vries equation as previously *** studies of the dynamics of plane waves in the line reveal the existence of three additional regions in the dispersion curve where the modulational phenomenon is *** the low frequency mode,we demonstrate that the network allows the propagation of dark and bright *** findings are in perfect agreement with the analytical predictions.

关键词： dissipative bi-inductance network low frequency mode continuous approximation complex Ginzburg-Landau equation

Effect of electrical discharge in water on concentration of nitrate solution

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Chinese Physics B 2017年第2期26卷 305-312页

作者： f Sohbatzadeh H Bagheri R Safari Department of Atomic and Molecular Physics Faculty of Basic Sciences University of Mazandaran Babolsar lra

In this work, the effect of electrical discharge on nitrate concentration is considered in aqueous solution. The atmospheric pressure plasma was produced by a high-voltage power supply at 27 k Hz using pin-to-pin configuration. Air, argon,and argon/methane mixture were used to study the working gas effect. UV-VIS spectroscopy and ion chromatography were used to analyze the effect of the electrical discharge on nitrate concentration in deionized water. Optical emission spectroscopy（OES） was applied to diagnose active species inside and on the surface of the deionized water solution. The results of the present work showed that the atmospheric pressure electric discharge with air increases nitrate concentration while it remains constant using argon and argon/methane electrical discharges. It was also revealed that in the presence of air, the electrical discharge reduces p H, acidifying the solution and increasing solution conductivity due to production of extra nitrate ions. On the other hand, argon electrical discharge increases p H and conductivity due to production of OHion in water.

关键词： electric discharge nitrate solution optical spectroscopy

Photocurrent improvement of an ultra-thin silicon solar cell using the localized surface plasmonic effect of clustering nanoparticles

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Chinese Physics B 2020年第6期29卷 532-537页

作者： f Sobhani H Heidarzadeh H Bahador Department of Electrical and Computer Engineering University of Mohaghegh ArdabiliArdabilIran

The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar *** we simulate spherical,conical,pyramidal,and cylindrical nanoparticles in a form of a cluster at the rear side of a thin silicon cell,using the finite difference time domain(fDTD)*** calculating the optical absorption and hence the photocurrent,it is shown that the clustering of nanoparticles significantly improves *** photocurrent enhancement is the result of the plasmonic effects of clustering the *** comparison,first a cell with a single nanoparticle at the rear side is *** four smaller nanoparticles are put around it to make a *** photocurrents of 20.478 mA/cm2,23.186 mA/cm2,21.427 mA/cm2,and 21.243 mA/cm2 are obtained for the cells using clustering conical,spherical,pyramidal,cylindrical NPs at the backside,*** values are 13.987 mA/cm2,16.901 mA/cm2,16.507 mA/cm2,17.926 mA/cm2 for the cell with one conical,spherical,pyramidal,cylindrical NPs at the backside,***,clustering can significantly improve the ***,the distribution of the electric field and the generation rate for the proposed structures are calculated.

关键词： clustering nanoparticles plasmonic solar cell localized surface plasmon resonance photocurrent finite difference time domain(fDTD)method light management

Dynamics of high-frequency modulated waves in a nonlinear dissipative continuous bi-inductance network

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Chinese Physics B 2021年第6期30卷 193-205页

作者： S M Ngounou f B Pelap Unitéde Recherche de Mécanique et de Modélisation des Systèmes Physiques(UR-2 MSP) Facultédes SciencesUniversitéde DschangBP 69 DschangCameroun Unitéde Recherche de Matière Condensée d'Electronique et de Traitement du Signal(UR-MACETS) Facultédes SciencesUniversitéde DschangBP 67 DschangCameroun

This paper presents intensive investigation of dynamics of high frequency nonlinear modulated excitations in a damped bimodal lattice. The effects of the dissipation are considered through a linear dissipation coefficient whose evolution in terms of the carrier wave frequency is checked. There appears that the dissipation coefficient increases with the carrier wave frequency. In the linear limit and for high frequency waves, study of the asymptotic behavior of plane waves reveals the existence of two additional regions in the dispersion curve where the modulational phenomenon is observed compared to the lossless line. Based on the multiple scales method exploited in the continuum approximation using an appropriate decoupling ansatz for the voltage of the two different cells, it appears that the motion of modulated waves is described by a dissipative complex Ginzburg–Landau equation instead of a Korteweg–de Vries equation. We also show that this amplitude wave equation admits envelope and hole solitons in the high frequency mode. from basic sources, we design a programmable electronic generator of complex signals with desired characteristics, which delivers signals exploited as input waves for all our numerical simulations. These simulations are performed in the LTspice software that uses realistic components and give the results that corroborate perfectly our analytical predictions.

关键词： dissipative bi-inductance network high-frequency mode continuous approximation dissipative complex Ginzburg–Landau equation programmable electronic generator LT-Pspice observations