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Effect of Seasonal Variations on the Behavior of Flexible Pavements in Burkina Faso: Towards Alternating and Periodic Loading of Multi-Axle Heavy Goods Vehicles for Road Durability

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Journal of materials Science and Chemical Engineering 2024年第6期12卷 24-42页

作者： Kokoro Kobori Doua Allain Gnabahou Bouto Kossi Imbga laboratoire de Chimie Analytique de Physique Spatiale et Energtique Universit Norbert ZONGO Koudougou Burkina Faso laboratoire dEnergie Thermique Renouvelable Universit Joseph KI-ZERBO Ouagadougou Burkina Faso

Bituminous materials are heat-sensitive, and their mechanical properties vary with temperature. This variation in properties is not without consequences on the performance of flexible road structures under the repeated passage of multi-axles. This study determines the influence of seasonal variations on the rate of permanent deformation, the rut depth of flexible pavements and the effect of alternating loading of heavy goods vehicles following the temperature variations on the durability of roads. Thus, an ambient and pavement surface temperature measurement was carried out in 2022. The temperature profile at different layers of the modelled pavement, the evaluation of deformation rates and rutting depth were determined using several models. The results show that the permanent deformation and rutting rates are higher at the level of the bituminous concrete layer than at the level of the asphalt gravel layer because the stresses decrease from the surface to the depth of the pavement. On the other hand, the variations in these rates, permanent deformations and ruts between the hot and so-called cold periods are more pronounced in the bitumen gravel than in bituminous concrete, showing that gravel bitumen is more sensitive to temperature variations than bituminous concrete despite its higher rigidity. Of these results, we suggested a periodic and alternating loading of the different types of heavy goods vehicles. These loads consist of fully applying the WAEMU standards with a tolerance of 15% during periods of high and low temperatures. This regulation has increased 2 to 3 times in the durability of roadways depending on the type of heavy goods vehicle.

关键词： Pavement Rutting Permanent Deformation Multi-Axle Seasonal

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The algebra of symmetric tensors on smooth projective varieties In Memory of Professor Gang Xiao

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Science China mathematics 2024年

作者： Arnaud Beauville Jie Liu cnrS Laboratoire J.-A.Dieudonné Université C?te d'Azur Institute of mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences

In this paper, we discuss the C-algebra H0(X, S~·TX) for a smooth complex projective variety *** compute it in some simple examples, and give a sharp bound on its Krull dimension. Then we propose a conjectural charac...

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Fast synthesis of gold nanoparticles by cold atmospheric pressure plasma jet in the presence of Au^(+) ions and a capping agent

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Plasma Science and Technology 2024年第7期26卷 108-115页

作者： Tatiana HABIB José Mauricio A.CAIUT Bruno CAILLIER laboratoire Diagnostics des Plasmas Hors Equilibre(DPHE) Universitéde ToulouseINU ChampollionAlbi 81000France Department of Chemistry The Nanomaterials and Luminescent Systems GroupFaculty of PhilosophyScience and Letters at Ribeirão PretoUniversity of São PauloRibeirão Preto-SP 14040-901Brazil

Homogeneous gold nanoparticles were synthesized under atmospheric pressure using a nonthermal helium plasma jet in a single-step process.A current power supply was used to generate the plasma discharge rich in diverse reactive *** species induce rapid chemical reactions responsible for the reduction of the gold salts upon contact with the liquid *** this study,spherical and monodispersed gold nanoparticles were obtained within 5 min of plasma exposure using a solution containing gold(Ⅲ)chloride hydrate(HAuCl_(4))as a precursor and polyvinylpyrrolidone(PVP)as a capping agent to inhibit *** formation of these metal nanoparticles was initially perceptible through a visible change in the sample's color,transitioning from light yellow to a red/pink *** was subsequently corroborated by UVvis spectroscopy,which revealed an optical absorption in the 520-550 nm range for Au NPs,corresponding to the surface plasmon resonance(SPR)*** investigation into the impact of various parameters,including plasma discharge duration,precursor and capping agent concentrations,was carried out to optimize conditions for the formation of well-separated,spherical gold *** light scattering(DLS)was used to measure the size of these nanoparticles,transmission electron microscopy(TEM)was used to observe their morphology and X-ray diffraction(XRD)was also employed to determine their crystallographic *** results confirm that homogeneous spherical gold nanoparticles with an average diameter of 13 nm can be easily synthesized through a rapid,straightforward,and environmentally friendly approach utilizing a helium atmospheric pressure plasma.

关键词： gold nanoparticles non-thermal plasma jet helium DBD

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Evolution of the 128-cm^(-1) Raman phonon mode with temperature in Ba(Fe_(1-x)Co_x)_2As_2(x=0.065 and 0.2)

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Chinese Physics B 2015年第2期24卷 399-402页

作者：杨彦兴 Gallais Yann 方之颢石兢熊锐 School of Physics and Technology Wuhan University laboratoire matériaux et Phénomenes Quantiques(umr 7162 cnrS) Université Paris Diderot-Paris 7

We report electronic Raman scattering measurements on Ba（Fei1-xCox）2As2（x = 0.065 and 0.2） single crystals with Raman shifts from 9 cm^-1 up to 600 cm^-1 in the symmetry of Blg with respect to 1 Fe unit *** the crystals are cooled down,the evident quasielastic peaks of Raman spectra occur only in the crystal with x = 0.065,which is due to the contribution of orbital ordering between xz and yz Fe 3d orbitals,as we reported in another ***,we analyze the Eg phonon at 128 cm^-1,which has the same function form of its Raman tensors as those of xz and yz Fe 3d orbitals in these two crystals *** their electronic continuums,no anomalies are found in the Eg phonons of these two samples,which simply follows the expressions corresponding to the anharmonic phonon decay into acoustic phonons with the same frequencies and opposite *** results indicate that the structural and magnetic phase transition might be completely suppressed by chemical doping and there is not any indication of coupling between charge nematicity and Eg phonon mode from our experimental results,which is consistent with the results in our previous work.

关键词： Raman scattering iron-based superconductor phonon mode

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Assessment of micro-scale heat exchangers efficiency using lattice Boltzmann method and design of experiments

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Energy and Built Environment 2024年第6期5卷 840-852页

作者： Mokhtar Ferhi Sameh Abidi Ridha Djebali Fateh Mebarek-Oudina UR22ES12:Modeling Optimization and Augmented Engineering ISLAIBUniversity of JendoubaBéja 9000Tunisia Higher Institute of Humanities of Jendouba University of JendoubaTunisia Department of Management Information Systems College of Business AdministrationQassim UniversityAl-RassAl-QassimSaudi Arabia Department of Physics Faculty of SciencesUniversity of 20 août 1955-SkikdaB.P 26 Road El-HadaiekSkikda 21000Algeria laboratoire des matériaux et Génie Energétique(LMGE) University of 20 août 1955-SkikdaSkikda 21000Algeria

The study is focused on the use of nanofluids in a micro-open tall cavity,which is a type of micro heat exchanger(MHE).The cavity is heated from the bottom sidewall in a sinusoidal pattern,and the effects of four input parameters(Ra,Ha,Kn,and Vf)on heat transfer and irreversibility are investigated using numerical simulations based on Lattice Boltzmann Method(LBM).The findings of the study suggest that the local heat transfer on the bottom sidewall is strongly influenced by Ra and Ha,while the surface distribution of entropy generation is mainly dependent on *** study also shows that the optimization of the magnitude and wavelength of the sinusoidal temperature can improve both local heat transfer and surface distribution of entropy *** results of the study provide valuable insights into the design of micro heat exchangers and suggest that the optimization of micro-porous geometries using DOE could lead to increased energy *** study contributes to our understanding of the complex interactions between input parameters in micro heat exchangers and highlights the importance of considering multiple parameters in the design process.

关键词： MHD Slip flow regime Micro heat exchanger Design of experiments Optimization

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A digital twin model-based approach to cost optimization of residential community microgrids

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Global Energy Interconnection 2024年第1期7卷 82-93页

作者： Mariem Dellaly Sondes Skander-Mustapha Ilhem Slama-Belkhodja Université de Tunis El Manar Ecole Nationale d’Ingénieurs de TunisLR11ES15 Laboratoire de Systèmes Electriques1002TunisTunisie Université de Carthage Ecole Nationale d’Architecture et d’UrbanismeLaboratoire de Systèmes Electriques1002TunisTunisie

This paper presents a peer-to-peer community cost optimization approach based on a single-prosumer energy management *** objective is to optimize energy costs for prosumers in the community by enhancing the consumption *** study was conducted along two main *** first axis focuses on designing a digital twin for a residential community microgrid *** phase involves data collection,cleaning,exploration,and ***,it includes replicating the functionality of the real platform and validating the *** second axis involves the development of a novel approach that incorporates two distinct prosumer behaviors within the same community microgrid,while maintaining the concept of peer-to-peer energy *** without storage utilize their individual PV systems to fulfill their energy requirements and inject excess energy into a local ***,a single prosumer with a storage system actively engages in energy exchange to maximize the community’s *** is achieved by optimizing battery usage using a cost optimization *** proposed solution is validated using the developed digital twin.

关键词： Energy management system(EMS) Cost optimization Digital twin Photovoltaic systems Microgrid

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Lateral ring compression test applied to a small caliber steel jacket:Identification of a constitutive model

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Defence Technology（防务技术） 2024年第6期36卷 133-148页

作者： Yann Coget Yael Demarty Christophe Czarnota Anthony Bracq Jean-Sebastien Brest Alexis Rusinek French-German Research Institute of Saint-Louis 5 Rue Du General Cassagnou68300 Saint-LouisFrance laboratoire d'Etude des Microstructures et de Mecanique des materiaux(LEM3) CNRSUniversite de LorraineArts&Metiers ParisTechF-57000 MetzFrance

The evolution of threats and scenarios requires continuous performance improvements of ballistic protections for armed *** a modeling point of view,it is necessary to use sufficiently precise material behavior models to accurately describe the phenomena observed during the impact of a projectile on a protective *** this context,the goal of this paper is to characterize the behavior of a small caliber steel jacket by combining experimental and numerical *** experimental method is based on the lateral compression of ring specimens directly machined from the thin and small *** speeds and temperatures are considered in a quasi-static regime in order to reveal the strain rate and temperature dependencies of the tested *** Finite Element Updating Method(FEMU)is *** results are coupled with an inverse optimization method and a finite element numerical model in order to determine the parameters of a constitutive model representative of the jacket *** of the present model are verified against experimental results and a parametric study as well as a discussion on the identified material parameters are *** results indicate that the strain hardening parameter can be neglected and the behavior of the thin steel jacket can be described by a modeling without strain hardening sensitivity.

关键词： Full metal jacket ammunition Lateral ring compression Inverse identification Numerical simulation

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Comparative Study between Dielectric Properties and Compaction Parameters: Case Study on Three Laterite Quarries

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Open Journal of Geology 2024年第8期14卷 746-759页

作者： Cheikh Diallo Diene Sabou Sarr Abdoulaye Cissé Mapathé Ndiaye laboratoire de Gophysique UFR Sciences de lIngnieur University Iba Der Thiam Thies Senegal laboratoire de Modlisation et de Mcanique des Sols UFR Sciences de lIngnieur University Iba Der Thiam Thies Senegal

This work studies the variability of the relationship between relative permittivity and compaction parameters as a function of certain geotechnical properties for different laterite types. This study allows to purpose the dielectric permittivity as a third compaction parameter allowing to obtain a non destructive control méthod. Preliminary studies on Diack laterite had shown a good correlation. Additional investigations are carried out to verify the possibility of generalizing this correlation to three new laterite careers: Ngoudiane, Yéba and Fandene. To proceed, particle size analysis, Atterberg limits, specific weight tests and compaction according to the modified Proctor test were performed on laterite samples. Using the radar method, experimental permittivities are determined for laterite samples by the point method of propagation times and confirmed by the diffraction hyperbole method. The geotechnical and radar data obtained allowed correlations between permittivity and water content on the one hand and between permittivity and dry density on the other. The results show that the maximum dry density as a function of permittivity corresponds with the optimum Proctor, which confirms the results previously obtained on Diack laterite.

关键词： Radar Laterite Moisture Content Dry Density Permittivity Geotechnical Properties

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Effect of Thermal Cycles on Creep Behavior of Bituminous Binder in Hot Regions

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Journal of Civil Engineering and Architecture 2024年第7期18卷 334-339页

作者： Bachir Glaoui Mahdjoub Bendjima M'hamed Merbouh Martin Van de Ven laboratoire de la Fiabilité des matériaux et Structures en Régions Sahariennes(FIMAS) Université de Béchar B.P.417Béchar08000Algérie Laboratory of Road and Railway Engineering TU DelftP.O.Box 50482600 GA DelftThe Netherlands

This research is devoted to the study of creep behavior of asphalt binder in hot *** binder was subjected to thermal cycles due to the variation of temperature from day to *** cycles produce a heating-cooling *** evaluate the effect of climate change in laboratory,the DSR(dynamic shear rheometer)was used,and the results found with the nine samples were *** thermal cycles led to aging and therefore hardening of the ***,a rheological model was proposed that can represent the curves obtained experimentally,where it is able to describe the creep behavior of binders tested.A new model is proposed that correlates well with the experimental curves,which is called A+2 K.

关键词： Bitumen temperature heating/cooling DSR BBR model

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Evaluation of Water Losses by Evaporation in the Nakanbe Basin

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Atmospheric and Climate Sciences 2024年第1期14卷 29-41页

作者： Bayala Alfred Kabre Sayouba Yonli Hamma Fabien Chesneau Xavier Thierry Sikoudouin Maurice Ky Zeghmati Belkacem Kieno P. Florent Kam Sié Unité de Formation et de Recherche en Sciences Exactes et Appliquées (UFR/SEA) Laboratoire d’Energies Thermiques Renouvelables (LETRE) Université Joseph KI-ZERBO Ouagadougou Burkina Faso Unité de Formation et de recherche en Science Exactes et Appliquées Centre Universitaire de Kaya (CU-K) Perpignan France laboratoire de Modélisation Pluridisciplinaire et Simulation Université de Perpignan Via Domitia Perpignan France Unité de Formation et de Recherche en Sciences Exactes et Appliquées (UFR/SEA) Laboratoire de Matériaux et Environnement Uni-versité Joseph KI-ZERBO Ouagadougou Burkina Faso laboratoire de Physique et Chimie de l’ Environnement (LPCE) Université Joseph KI-ZERBO Ouagadougou Burkina Faso

A numerical approach to heat and mass transfer in a large water reservoir is presented. This water reservoir is likened to a parallelepiped reservoir whose vertical and lower walls are adiabatic and impermeable. The equations that govern natural convection in water are solved by the finite volume method and Thomas’salgorithm. The adequacy between the velocity and pressure fields is ensured by the SIMPLE algorithm. We are going to evaluate the water losses by evaporation from three dams in the Nakanbé basin in Burkina Faso for a period of thirty years, that is to say from January 1, 1991, to March 15, 2020. The three dams have a rate of evaporation greater than 40% of the volume of water stored. Indeed the rate of evaporation in each dam increases with the water filling rate in the reservoir: we have observed the following results for each dam in the Nakanbé basin;for the date of 02/27/1988 to 03/13/2020., the Loumbila dam received a total volume of stored water of 22.02 Mm3 and 10.57 Mm3 as the total volume of water evaporated at the same date. At the Ouaga dam (2 + 3), it stored a water volume of 4.06 Mm3 and evaporated 2.03 Mm3 of its storage volume from 01/01/1988 to 05/07/2016. Finally, with regard to the Bagré dam, it stored 745.16 Mm3 of water and 365.13 Mm3 as the volume of water evaporated from 01/01/1993 to 03/31/2020.

关键词： Numerical Study Evaporation Meteorological Data Natural Convection Basins Dams

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