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Soliton excitations in a polariton condensate with defects

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Chinese Physics B 2018年第1期27卷 278-283页

作者： Abderahim Mahmoud Belounis Salem Kessal SNIRM laboratory Faculty of Physics Universite des Sciences et de la Technologie Houari Boumediene (USTHB)

To study soliton excitations in a polariton condensate with defects, we use the Gross-Pitaevskii equation and its hydrodynamic form. An extra term is added to take into account the non-equilibrium nature of the polariton condensate and the presence of defects. The reductive perturbation method transforms these hydrodynamic equations into a modified Korteweg-de Vries equation in the long wavelength limit. We linearize this equation and study the soliton linear excitations. We give an analytic expression of traveling excitations using the variation of constants method. In the more general form, we show numerically that the excitations are oscillations simultaneously hut in an opposite way. i.e., the amplitude and the width of the dark soliton oscillate

关键词： solitons polariton condensates reductive perturbation method

Analysis of a quasistatic contact problem with adhesion and nonlocal friction for viscoelastic materials

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Applied Mathematics and Mechanics(English Edition) 2010年第5期31卷 623-634页

作者： Arezki TOUZALINE laboratoire de Systèmes Dynamiques Facult de Mathmatiques Universit des Sciences et de la Technologie Houari Boumediene

A mathematical model is established to describe a contact problem between a deformable body and a foundation. The contact is bilateral and modelled with a nonlocal friction law, in which adhesion is taken into account. Evolution of the bonding field is described by a first-order differential equation. The materials behavior is modelled with a nonlinear viscoelastic constitutive law. A variational formulation of the mechanical problem is derived, and the existence and uniqueness of the weak solution can be proven if the coefficient of friction is sufficiently small. The proof is based on arguments of time-dependent variational inequalities, differential equations, and the Banach fixed-point theorem.

关键词： viscoelastic materials adhesion nonlocal friction fixed point weak solution

Oxidation of propane over substituted Keggin phosphomolybdate salts

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Journal of Natural Gas Chemistry 2009年第3期18卷 319-324页

作者： T.Mazari C.Roch.Marchal S.Hocine N.Salhi C.Rabia laboratoire de Chimie du Gaz Naturel Faculté de ChimieUniversité des Sciences et de la Technologie Houari Boumediéne ILV-UMR 8180 CNRS-université de Versailles-St Quentin-en-Yvelines Batiment Lavoisier45 avenue des Etats-Unis78035 Versailles CedexFrance

Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by Bet method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.

关键词： propane oxidation propene acrolein polyoxometalates phosphomolybdate

Unveiling the Residual Stresses,Local Micromechanical Properties and Crystallographic Texture in a Ti-6Al-4V Weld Joint

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Acta Metallurgica Sinica(English Letters) 2021年第7期34卷 997-1006页

作者： B.Mehdi R.Badji V.Ji B.Alili D.Bradai W.Bedjaoui F.deschaux-Beaume F.Brisset laboratoire de Physique des Matériaux Facul téde PhysiqueUniversitéDes Sciences Et de La Technologie Houari Boumediene16111 AlgerAlgérie Research Center in Industrial technologies CRTI P.O.Box64CheragaAlgeria ICMMO/SP2M UniversitéParis-Saclay LMGC University of MontpellierCNRSMontpellierFrance

In this work,the micromechanical properties,crystallographic texture,welding residual stresses and their evolution after plastic strain were investigated in a Ti-6Al-4V alloy tungsten inert gas weld *** was found that the welding process affected the Young modulus and microhardness values in bothαandβphases in the different regions of the weld *** highest microhardness and Young modulus values of a phase were recorded in the heat-affected zone,whereas the highest values of these characteristics for theβphase were found in the fusion zone(FZ).The change in the micro mechanical properties was accompanied by a change in the crystallographic texture components of the dominant a phase from(0001)and(11-20)components in the base material to(10-10)and(11-20)components in the *** introduction of tensile testing resulted in a continuous stress relaxation and improved the weld joint performances.

关键词： Ti-6Al-4 V Tungsten inert gas(TIG)weld Residual stress Local mechanical properties Crystallographic texture

Static and dynamic stability responses of multilayer functionally graded carbon nanotubes reinforced composite nanoplates via quasi 3D nonlocal strain gradient theory

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defence Technology（防务技术） 2022年第10期18卷 1778-1809页

作者： Ahmed Amine Daikh Mohamed Sid Ahmed houari Mohamed Ouejdi Belarbi Salwa A.Mohamed Mohamed A.Eltaher laboratoire D'etude des Structures et de Mecanique des Materiaux Departement de Genie CivilFacultedes Sciences et de La TechnologieUniversite Mustapha Stambouli B.P.305R.P.29000MascaraAlgeria laboratoire de Genie Energetique et Materiaux LGEMUniversite de BiskraB.P.145R.P07000BiskraAlgeria department of Engineering Mathematics Zagazig UniversityP.O.Box 44519ZagazigEgypt Faculty of Engineering Mechanical Engineering DepartmentKing Abdulaziz UniversityP.O.Box 80204JeddahSaudi Arabia Faculty of Engineering Mechanical Design and Production DepartmentZagazig UniversityP.O.Box 44519ZagazigEgypt

This manuscript presents the comprehensive study of thickness stretching effects on the free vibration,static stability and bending of multilayer functionally graded(FG)carbon nanotubes reinforced composite(CNTRC)*** nanoscale and microstructure influences are considered through a modified nonlocal strain gradient continuum *** on power-law functions,four different patterns of CNTs distribution are considered in this analysis,a uniform distribution UD,FG-V CNTRC,FG-X CNTRC,and FG-O CNTRC.A 3D kinematic shear deformation theory is proposed to include the stretching influence,which is neglected in classical ***'s principle is applied to derive the governing equations of motion and associated boundary *** solutions are developed based on Galerkin method to solve the governing equilibrium equations based on the generalized higher-order shear deformation theory and the nonlocal strain gradient theory and get the static bending,buckling loads,and natural frequencies of *** with previous works is presented.A detailed parametric analysis is carried out to highlight the impact of thickness stretching,length scale parameter(nonlocal),material scale parameter(gradient),CNTs distribution pattern,geometry of the plate,various boundary conditions and the total number of layers on the stresses,deformation,critical buckling loads and vibration *** new results are also reported in the current study,which will serve as a benchmark for future research.

关键词： 3D shear deformation theory Free vibration Buckling Bending Galerkin method Functionally graded nanotube Nonlocal strain gradient theory

degradation of direct azo dye by Cucurbita pepo free and immobilized peroxidase

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Journal of Environmental sciences 2013年第6期25卷 1235-1244页

作者： Nabila Boucherit Mahmoud Abouseoud Lydia Adour université Mouloud Mammeri laboratoire de Biomatériaux et de Phénomènes detransports Université Dr.Yahia Fares laboratoire de Biomatériaux et de Phénomènes de Transports Université Dr.Yahia Fares laboratoire de Génie de la Réaction Faculté de Génie Mécanique et Génie des ProcédésUniversité Houari Boumediene laboratoire des Biotechnologies Environnementales et Génie des Procédés

Enzymatic decolourization of the azo dye, Direct Yellow （DY 106） by Cucurbita pepo （courgette） peroxidase （CP） is a complex process, which is greatly affected by pH, temperature, enzyme activity and the concentrations of H202 and dye. Courgette peroxidase was extracted and its performance was evaluated by using the free-CP （FCP） and immobilized-CP （ICP） forms in the decolourization of DY106. Immobilization of peroxidase in calcium alginate beads was performed according to a strategy aiming to minimize enzyme leakage and keep its activity at a maximum value by optimizing sodium alginate content, enzyme loading and calcium chloride concentration. The initial conditions ~it which the highest DY106 decolourization yield was obtained were found at pH 2, temperature 20~C, H202 dose 1 mmol/L （FCP） and 100 mmol/L （ICP）. The highest decolourization rates were obtained for dye concentrations 50 mg/L （FCP） and 80 mg/L （ICP）. Under optimal conditions, the FCP was able to decolorize more than 87% of the dye within 2 min. While with ICP, the decolourization yield was 75% within 15 rain. The decolourization and removal of DY106 was proved by UV-Vis analysis. Fourier transform infrared （FF-IR） spectroscopy analysis was also performed on DY106 and enzymatic treatment precipitated byproduct.

关键词： Cucurbita pepo peroxidase immobilization decolourization azo dye

Oxidation of propane over ammonium-transition metal mixed keggin phosphomolybdate salts

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Journal of Natural Gas Chemistry 2010年第1期19卷 54-60页

作者： T. Mazari C. Roch. Marchal S. Hocine N. Salhi C. Rabia laboratoire de Chimie du Gaz Naturel Faculte' de Chimie Universite' des Sciences et de la Technologie Houari Boumedie`ne USTHB BP32 El-Alia Bab-Ezzouar Alger Alge'rie ILV-UMR 8180 CNRS Universite' de Versailles -St Quentin-en-Yvelines Ba?timent Lavoisier 45 avenue des Etats-Unis 78035 Versailles Cedex France

Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature range between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9℃/min. They were characterized by Bet method, XRD, UV-Vis and IR techniques. The catalysts were found to be active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9℃/min. FePMo12 was found to be a more active catalyst for propene （17.2% yield） with minimal over deep oxidation （0.3% yield in COx）.

关键词： phosphomolybdate ammonium keggin propane oxidation propene acrolein

Analytical fits to the synchrotron functions

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Research in Astronomy and Astrophysics 2013年第6期13卷 680-686页

作者： Mourad Fouka Saad Ouichaoui Research Center in Astronomy Astrophysics and GeophysicsB. P. 63 Algiers ObservatoryBouzaréah Algiers Algeria université des sciences et de la technologie houari Boumediène (USTHB) Faculté dePhysique Laboratoire SNIRMB.P. 32 El-Alia 16111 Bab Ezzouar Algiers Algeria

Accurate fitting formulae to the synchrotron function, F（x）, and its com- plementary function, G（x）, are performed and presented. The corresponding relative errors are less than 0.26% and 0.035% for F（x） and G（x）, respectively. To this end we have, first, fitted the modified Bessel functions, Ks/3（x） and K2/3（x）. For all the fitted functions, the general fit expression is the same, and is based on the well known asymptotic forms for low and large values of z for each function. It consists of multi- plying each asymptotic form by a function that tends to unity or zero for low and large values of z. Simple formulae are suggested in this paper, depending on adjustable parameters. The latter have been determined by adopting the Levenberg-Marquardt algorithm. The proposed formulae should be of great utility and simplicity for com- puting spectral powers and the degree of polarization for synchrotron radiation, both for laboratory and astrophysical applications.

关键词： radiation processes: non thermal -- methods: analytical

Rh/ZnO-Al_2O_3催化剂用于巴豆醛选择性加氢(英文)

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催化学报 2011年第7期32卷 1185-1190页

作者： Mouna AOUN Aicha BENAMAR Mohamed CHATER Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques(C.R.A.P.C) laboratoire d'etude Physico-Chimique des Matériaux et Application à l'Environnement Faculté de ChimieUniversité des Sciences et de la Technologie

Gas phase hydrogenation of crotonaldehyde was performed over 1 wt% Rh/ZnO-Al2O3 catalysts with various Zn/Rh atomic ratios. Monometallic Rh/Al2O3 was also prepared for comparison. The samples were prepared by the successive impregnation of Al2O3 with chlo-ride precursors of zinc and rhodium. The solids have been characterized by H2 chemisorption,temperature-programmed reduction,scanning electron microscopy,and cyclohexane dehydrogenation. Their catalytic behaviour in the gas phase crotonaldehyde hydrogenation reaction after reduction treatment in flowing hydrogen at 723 K was investigated. The relationship between catalytic activity,selectivity for crotyl alcohol,and physicochemical properties of the catalysts was examined. Results obtained showed that the presence of Zn clearly promotes the hydrogenation of the carbonyl bond. The catalyst with Zn/Rh atomic ratio of 5 displayed good catalytic stability and the highest selectivity for crotyl alcohol(70%) along with alloy formation.

关键词： rhodium-based catalyst crotonaldehyde hydrogenation zinc oxide selectivity