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Thermal comfort of Frail People under dynamic and non-uniform thermal environments using a thermal manikin with thermoregulatory control:An experimental study

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Energy and Built Environment 2023年第4期4卷 477-491页

作者： Zoubayre El akili youcef bouzidi Abdelatif Merabtine Guillaume Polidori Julien Kauffmann Interdisciplinary research on Society-Technology-Environment interactions.University of Technology of Troyes TroyesFrance EPF School of Engineering.Rosières-Prés-Troyes France MATIM Faculty of Exact and Natural Sciences.University of Reims Champagne Ardenne.ReimsFrance

The thermal comfort of frail people has to be considered carefully,mainly because of the high thermal sensitivity of this population and the negative influences that unsatisfactory thermal conditions have on their *** existing thermal comfort works have been conducted under steady-state,uniform thermal environments,with far fewer being performed in dynamic and non-uniform thermal environments,and even less for frail *** study aimed at assessing the thermal responses of frail people under transient and non-uniform thermal environments,using a thermal manikin and a climatic test *** responses were investigated and discussed in both *** analysis of variance showed a significant difference in thermal comfort and thermal sensation between females and males over time,under hot *** cold exposure,results showed a significant difference in thermal sensation between females and males over time,but no significant difference was observed in term of thermal *** revealed also significant differences in the dynamic thermal sensation between the sexes under cold exposure,while results confirmed that there is no significant difference in the dynamic thermal sensation between sexes under hot exposure.

关键词： Building Energy conservation Thermal comfort Thermal sensation Thermal manikin

A Model of Grid Service Capacity

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Journal of Computer Science & Technology 2007年第4期22卷 505-514页

作者： youcef Derbal School of Information Technology Management Ryerson University350 Victoria StreetTorontoONM5B 2K3Canada

Computational grids （CGs） are large scale networks of geographically distributed aggregates of resource clusters that may be contributed by distinct organizations for the provision of computing services such as model simulation, compute cycle and data mining. Traditionally, the decision-making strategies underlying the grid management mechanisms rely on the physical view of the grid resource model. This entails the need for complex multi-dimensional search strategies and a considerable level of resource state information exchange between the grid management domains. In this paper we argue that with the adoption of service oriented grid architectures, a logical service-oriented view of the resource model provides a more appropriate level of abstraction to express the grid capacity to handle incoming service requests. In this respect, we propose a quantification model of the aggregated service capacity of the hosting environment that is updated based on the monitored state of the various environmental resources required by the hosted services. A comparative experimental validation of the model shows its performance towards enabling an adequate exploitation of provisioned services.

关键词： computational grids service provision resource model service capacity

Sequential extraction of Cs and Sr from Ain Oussera soils around Es-Salam research reactor facility

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Journal of Environmental Sciences 2015年第10期27卷 163-172页

作者： Abdelkader bouzidi Abderrahmane Ararem Djillali Imessaoudene Benalia Yabrir Centre de Recherche Nucléaire de Birine 17200 Ain OusseraAlgeria Laboratory of Exploration and Valorization of Steppic Ecosystems University of Djelfa

Four types of undisturbed soil in Ain Oussera region around the Es-Salam reactor facility,located in the south of Algiers, Algeria, at about 200 km, were artificially contaminated for one year with stable CsCl and SrCl2 in order to simulate an accidental release of these elements. This study was performed using sequential extraction procedure based on Shultz method and containing six fractions. The selectivity of the extraction protocol was confirmed by analyzing some elements（Ca, C, Fe, Mn, Si and Al） designed as indicators of the targeted phases. The obtained results showed an acceptable reproducibility, in view of the coefficients of variation that were in most cases less than 15%. The results revealed a clear proportional correlation between the extracted Cs and Sr in fractions for each soil and some of soils physicochemical properties. Organic matter appears to play an important role in the soil retention, particularly for Cs where the extracted percentage exceeds to 30% in whole soils. In contrast, strontium expresses a remarkable affinity for the fraction bound to carbonates. The obtained data also indicate that the availability of Cs in the four soils is less important compared to Sr availability. This is illustrated by the higher value of extracted Sr in the easily extractible phase, including the water-soluble and the exchangeable fraction.

关键词： Ain Oussera soils CsCl SrCl2 Sequential extraction Selectivity

On the Controllability of an Advection-diffusion Equation with Respect to the Diffusion Parameter:Asymptotic Analysis and Numerical Simulations

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Acta Mathematicae Applicatae Sinica 2019年第1期35卷 54-110页

作者： youcef AMIRAT Arnaud MNCH Laboratoire de Mathématiques Blaise Pascal Université Clermont Auvergne UMR CNRS 6620 Campus universitaire des Cézeaux

The advection-diffusion equation y_t~ε-εy_(xx)~ε+ M y_x~ε= 0,(x, t) ∈(0, 1) ×(0, T) is null controllable for any strictly positive values of the diffusion coefficient ε and of the controllability time T. We discuss here the behavior of the cost of control when the coefficient ε goes to zero, according to the values of T. It is actually known that this cost is uniformly bounded with respect to ε if T is greater than a minimal time T_M, with T_M in the interval [1, 2×3^(1/2)]/M for M > 0 and in the interval [2×2^(1/2), 2(1 +3^(1/2))]/|M | for M < 0. The exact value of TM is however *** investigate in this work the determination of the minimal time T_M employing two distincts but complementary approaches. In a first one, we numerically estimate the cost of controllability, reformulated as the solution of a generalized eigenvalue problem for the underlying control operator, with respect to the parameter T and ε. This allows notably to exhibit the structure of initial data leading to large costs of control. At the practical level, this evaluation requires the non trivial and challenging approximation of null controls for the advection-diffusion equation. In the second approach, we perform an asymptotic analysis, with respect to the parameter ε, of the optimality system associated to the control of minimal L^2-norm. The matched asymptotic expansion method is used to describe the multiple boundary layers.

关键词： numerical approximation space-time variational formulation asymptotic analysis boundary layers null controllability

Effect of Agitator’s Types on the Hydrodynamic Flow in an Agitated Tank

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Chinese Journal of Mechanical Engineering 2020年第2期33卷 122-139页

作者： Mohammed Foukrach Mohamed Bouzit Houari Ameur youcef Kamla Mechanical Faculty of Engineering University of Sciences and Technology of Oran Mohamed Boudhief(USTO-MB)1505 El M’naouarOranAlgeria Institute of Science and Technology University Center of Naama(Ctr Univ Naama)BP 6645000 NaamaAlgeria Faculty of Technology University Hassiba Ben Bouali of Chlef(UHBC)Ouled FaresChlefAlgeria

The aim of this paper is to study the effect of agitator’s types on the turbulent flows in stirred tanks without and with *** hydrodynamics behavior induced by four different agitator’s types:a Rushton turbine(RT),a circular blade turbine(CBT),a diverging triangular blade turbine(DTBT)and converging triangular blade turbine(CTBT)are numerically predicted by solving the Navier-Stokes equations and RNGκ–εturbulent *** simulations are carried out using the Multi Reference Frame(MRF)*** numerical results showed good agreement with *** find that the agitator CTBT gives an important profit on the power consumption per report/ratio the others and DTBT give a good reduction of the vortex size of the impeller angles.

关键词： Mixing Baffled tanks Agitators Reynolds number Turbulent flow

Non linear modeling of three-dimensional reinforced and fiber concrete structures

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Frontiers of Structural and Civil Engineering 2018年第4期12卷 439-453页

作者： Fatiha IGUETOULENE youcef BOUAFIA Mohand Said KACHI University Mouloud Mammeri of Tizi-Ouzou 15000Algeria

Under the effect of the ascending loading, the behavior of reinforced concrete structures is rather non linear. Research in industry and science aims to extend forward the use of non-linear calculation of fiber concrete for structural parts such as columns, veils and pious, as the fiber concrete is more ductile behavior then the classical concrete behavior. The formulation of the element has been established for modeling the nonlinear behavior of elastic structures in three dimensions, based on the displacement method. For the behavior of concrete and fiber concrete compressive and tensile strength (stress-strain) the uniaxial formulation is used. For steel bi-linear relationship is used. The approach is based on the discretization of the cross section trapezoidal tables. Forming the stiffness matrix of the section, the integral of the surface is calculated as the sum of the integrals on each of the cutting trapezoids. To integrate on the trapeze we have adopted the type of Simpson integration scheme.

关键词： numerical modeling column and beam nonlinear analysis fibers pious reinforcement 3D formulation response load-deflection

The productivity of two serial chemostats

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生物数学学报:英文版 2023年第6期16卷 57-111页

作者： Manel Dali-youcef Tewfik Sari MISTEA L'institut Agro Montpellier INRAEUniversite Montpellier2 Place Pierra Viala F-34060 Montpellier Cedec 2France ITAP L'Institut Agro MontpellierINRAE UniversitéMontpellier361 rue Jean-Francois Breton BP 5095F-34196 Montpellier Cedea 5France

This paper considers the production of biomass of two interconnected chemostats in series with biomass mortality and a growth kinetic of the biomass described by an increasing function.A comparison is made with the productivity of a single chemostat with the same mortality rate and with volume equal to the sum of the volumes of the two *** determine the operating conditions under which the productivity of the serial configuration is greater than the productivity of the single ***,the differences and similarities in the results corresponding to the case with mortality and the one without mortality,are *** mortality leads to surprising results where the productivity of a steady state where the bacteria are washed out in the first chemostat is greater than the one where the bacteria are present in both chemostats.

关键词： Chemostat gradostat mortality bifurcations global stability operating diagram biomass productivity

Attenuation of Rayleigh Surface Waves in a Porous Material

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Chinese Physics Letters 2012年第4期29卷 123-125页

作者： DEBBOUB Salima BOUMAIZA youcef BOUDOUR Amar TAHRAOUI Tarek Laboratory of Materials Elaboration and Analysis Department of PhysicsFaculty of SciencesUniversity of AnnabaP.O.BOX 1223000 AnnabaAlgeria

Using acoustic microscopy at higher frequency,we show the velocity evolutions of surface acoustic waves,in particular Rayleigh waves that depend on porosity for a mesoporous silicon *** velocities are obtained from different V(z) curves,which are determined experimentally at a frequency of *** analysis of V(z) data yields attenuation that is directly dependent on *** the other hand,αN attenuation has been modeled and allows us to investigate its influence on the velocity VR of the propagation for Rayleigh waves.

关键词： layer porosity Porous

Nonlinear analysis and reliability of metallic truss structures

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Frontiers of Structural and Civil Engineering 2018年第4期12卷 577-593页

作者： Karim BENYAHI youcef BOUAFIA Salma BARBOURA Mohand Said KACHI LaMoMs Laboratory University Mouloud Mammeri of Tizi-Ouzou15000Tizi-OuzouAlgeria C.N.R.S.LSPM-UPR 3407Laboratory Paris13UniversityParisFrance

The present study goes into the search for the safety domain of civil engineering structures. The objective is to show how a reliability-evaluation brought by a mechanical sizing can be obtained. For that purpose, it is necessary to have a mechanical model and a reliability model representing correctly the behavior of this type of structure. It is a question on one hand, to propose a formulation for the nonlinear calculation (mechanical nonlinearity) of the spatial structures in trusses, and on the other hand, to propose or to adapt a formulation and a modeling of the reliability. The principle of Hasofer-Lind can be applied, in first approach, for the reliability index estimation, scenarios and the probability of failure. The made check concerned metallic in truss structures. Finally, some structures are calculated using the method adapted by Hasofer-Lind to validate the probability approach of the reliability analysis.

关键词： modeling nonlinearity mechanical truss probability reliability response surface probability of failure