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Geomaterials 2023年第3期13卷 51-60页

作者： Mohamadou Moustapha Thiam Adama Dione Moumar Dieye Diakher Hélène Madioune Diodio Diouf ecole nationale supérieure des Mines et de la Géologie Cheikh Anta Diop University Dakar Senegal Département de Géologie Cheikh Anta Diop University Dakar Senegal

Limestones of different facies in the Senegal basin are most commonly used as aggregates, regardless of their petrographic properties. These differences may influence their behaviour. The aim of this paper is to study the stratigraphy and characterise the limestones of the Bandia and Popenguine quarries. Sampling and geochemical and geotechnical characterisation were carried out on these limestones. The results show the presence of several very different facies in the Paleocene formation. The geochemical study shows that the Bandia limestones (Bd2) have the highest CaCO3 percentages (98.54%) and the highest SiO2 percentages were recorded in the Popenguine limestones (Pop2). The study also gives Mde values of 22.38 and LA of 22, which are acceptable for use in road construction. It is important to carry out a complete study in order to select the right materials for optimal use.

关键词： Stratigraphy Paleocene Geochemical Limestone Bandia Popenguine

Can earthen architectural heritage save us?

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Built Heritage 2021年第3期5卷 99-109页

作者： Sebastien Moriset Bakonirina Rakotomamonjy David Gandreau Centre international de la construction en terre Ecole Nationale Supérieure d’architecture de GrenobleCRAterreCS 12636‑38036 GRENOBLECedex 2France

Contemporary architecture seems to turn its back on the past in terms of the raw materials taken from the environ‑ment,their transformation into building components and the way they are assembled to create *** global challenge of preserving the environment forces us to rethink the way we produce architecture *** this challenge,the past shows us possible ways to fll the gap between tradition and ***,we need to understand what motivates people to abandon ancestral materials and knowledge for materials that they cannot manufacture or use *** this transformation to industrial materials and forms irreversible?Is there nothing we can learn from our rich past?How can we revive endogenous knowledge to produce environmentally wise archi‑tecture?These are the questions that the authors,who have been working on the revival of earthen heritage for over 20 years,wish to answer.

关键词： Learning from the past Endogenous knowledge Earthen architecture Sustainable architecture

Calculation and application of partition coefficients of light hydrocarbons in oil-based mud system

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Petroleum Exploration and development 2022年第4期49卷 906-918页

作者： BEN ABDALLAH Bacem Rabie AHMADI Riadh LYNEN Frederic REKHISS Farhat Laboratoire LR3E.ecole nationale d’Ingénieurs de Sfax Rte Soukra km 3SfaxTunisia Separation Science Group Department of Organic and Macromolecular ChemistryGhent UniversityKrijgslaan 281-S4B-9000 GhentBelgium

To find out the relationship between the oil-based mud,the formation fluid and the extracted gas,we use a thermodynamic approach based on static headspace gas chromatography technique to calculate the partition coefficients of 47 kinds of light hydrocarbons compounds between nC5 and nC8 in two kinds of oil-based mud-air systems,and reconstruct the original formation fluid composition under thermodynamic *** oil-based drilling mud has little effect on the formation fluid compositions in the range of nC5-nC8(less than 1%for low-toxicity oil-based mud and less than 10%for oil-based mud).For most light hydrocarbon compositions,the partition coefficients obtained by vapor phase calibration and the direct quantitative methods have errors of less than 10%,and the partition coefficients obtained by direct quantitative method are more *** reconstructed compositions of the two kinds of crude oil have match degrees of 91%and 89%with their real compositions,proving the feasibility and accuracy of reconstructing the composition of original formation fluid by using partition coefficients of light hydrocarbon compositions between nC5 and nC8.

关键词： oil-based mud drilling mud gas light hydrocarbon compositions partition coefficients reservoir fluid

Integration of automatic voltage regulator and power system stabilizer: small-signal stability in DFIG-based wind farms

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Journal of Modern Power Systems and Clean Energy 2019年第5期7卷 1115-1128页

作者： Sirine ESSALLAH Adel BOUALLEGUE Adel KHEDHER universite de Sousse Ecole Nationale d’Ingenieurs de SousseLATIS-Laboratory of Advanced Technology and Intelligent Systems4023 SousseTunisia

The increasing penetration of wind farms in the energy sector directly affects the dynamic behavior of the power *** increasing use of wind energy in the power system worsens its stability and inherently influences the firmness of a small *** investigate these effects,one of the synchronous generators(SGs)of the grid is considered defective and is replaced by a doubly fed induction generator(DFIG)-based wind farm of the same *** small-signal stability of a power system is usually evaluated via eigenvalue analysis where local-area and inter-area oscillatory modes for the New England test system are *** controls,such as automatic voltage regulator(AVR)and power system stabilizer(PSS),are added to attenuate the generated *** this study,the impact of wind energy on the small-signal stability of the power system is *** combinations of AVR and PSS types are considered to mitigate the undesirable alterations.A comparative study is performed based on numerical simulations to choose the best combination of AVR and PSS *** obtained results prove that the proposed combination yields good results in terms of stability enhancement both under normal operating conditions and in DFIG-based wind farms.

关键词： Power system stability Power transmission system Transient analysis Voltage regulation

Thermal Activation of Asymetrical Composites for Vibration Control

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Modern Mechanical Engineering 2013年第3期3卷 1-8页

作者： Axel Imbert Gildas L’Hostis David Rigel Rigel Fabrice Laurent Bernard Durand Centre Technique des Industrie Mécanique Centre Recherche Matériaux Textiles Mulhouse France fabrice.laurent@uha.fr Laboratoire de Physiques et Mécanique Ecole Nationale d’Ingénieur de Sud Alsace Mulhouse France Laboratoire de Physiques et Mécanique Ecole Nationale d’Ingénieur de Sud Alsace Mulhouse France Laboratoire de Physiques et Mécanique Ecole Nationale d’Ingénieur de Sud Alsace Mulhouse France Centre Technique des Industrie Mécanique Centre Recherche Matériaux Textiles Mulhouse France

The CBCM (Controlled Behaviour Composite Material) is a thermal active composite, which has been developed for morphing applications. The thermal activation is made by a source of heating generated within the composite structure. The coupling between the induced thermal field and the thermomechanical properties of the various components of the composite structure leads to the change of the structure shape. The heat source is generated by Joule effect, Carbon yarns inserted in the composite, are connected to a power supply. The application field of CBCM technology is the domain of shape modification and active assembly. The objective of this work is to illustrate the capabilities of CBCM in the domain of vibration control. We will study several reference plates with different constitution. The influences of these different constitutions, of the CBCM effect and the loss of stiffness for the matrix will be highlighted, for two boundary conditions, free/free and embedded/embedded.

关键词： Composite Material Vibration Control Smart Materials Active Structure

Mechanical Characterisation of Interface for Steel/Polymer Composite Using Pull-out Test: Shear-Lag and Frictional Analysis

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Journal of Materials Science & Technology 2006年第4期22卷 552-558页

作者： Mohamed KHARRAT Maher DAMMAK Amine CHARFI Institut Préparatoire aux Etudes d'Ingénieurs de Sfax Tunisia Laboratoire des Systèmes ElectromécaniquesEcole Nationale d'Ingénieurs de SfaxTunisia Laboratoire des Systèmes Electromécaniques Ecole Nationale d'Ingénieurs de SfaxTunisia

Fibre-matrix interface is known to have contribution to the mechanical performance of fibre-reinforced composite by its potential for load transfer between the fibre and the matrix. Such load transfer is of great importance in dentistry when a post is used for fixing a ceramic crown on the tooth. In this study, a pull-out test was carried out to analyse the interfacial properties of a steel fibre embedded in a polyester and epoxy matrices. It was found that the fibre-matrix interface is debonded on the whole embedded length when the fibre stress reached the debonding stress. Then, the fibre stress fell down to the initial extraction stress required to pulling out the debonded fibre from the matrix. Both debonding stress and initial extraction stress initiated a linear increase with the implantation length after the debonding stress reached horizontal asymptotes. To analyse the fibre-matrix load transfer before debonding, an analytical shear-lag model was adopted to in this test conditions. Fitting the experimental results with the analytical model provided the interfacial shear strength. By considering the Coulomb friction at the fibre-matrix interface during the fibre extraction process, an analytical model which considers Poisson＇s effects on both fibre and matrix, was developed. In this model, knowledge of the initial extraction stress of the fibre provides the residual normal stress at the fibre-matrix interface.

关键词： Fibre Matrix Interface Pull-out Shear-lag debonding Friction

3D random Voronoi grain-based models for simulation of brittle rock damage and fabric-guided micro-fracturing

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Journal of Rock Mechanics and Geotechnical Engineering 2014年第6期6卷 506-521页

作者： E.Ghazvinian M.S.Diederichs R.Quey Geo Engineering Centre Queen's UniversityKingston ON Canada ecole nationale supérieure des Mines de Saint-Etienne CNRS UMR 5307 France

A grain-based distinct element model featuring three-dimensional （3D） Voronoi tessellations （randompoly-crystals） is proposed for simulation of crack damage development in brittle rocks. The grainboundaries in poly-crystal structure produced by Voronoi tessellations can represent flaws in intact rockand allow for numerical replication of crack damage progression through initiation and propagation ofmicro-fractures along grain boundaries. The Voronoi modelling scheme has been used widely in the pastfor brittle fracture simulation of rock materials. However the difficulty of generating 3D Voronoi modelshas limited its application to two-dimensional （2D） codes. The proposed approach is implemented inNeper, an open-source engine for generation of 3D Voronoi grains, to generate block geometry files thatcan be read directly into 3deC. A series of Unconfined Compressive Strength （UCS） tests are simulated in3deC to verify the proposed methodology for 3D simulation of brittle fractures and to investigate therelationship between each micro-parameter and the model＇s macro-response. The possibility of numericalreplication of the classical U-shape strength curve for anisotropic rocks is also investigated innumerical UCS tests by using complex-shaped （elongated） grains that are cemented to one another alongtheir adjoining sides. A micro-parameter calibration procedure is established for 3D Voronoi models foraccurate replication of the mechanical behaviour of isotropic and anisotropic （containing a fabric） rocks. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

关键词： Numerical modelling 3D Voronoi tessellation Discrete element method Grain-based model Crack damage thresholds Fabric-guided micro-fracturing Anisotropy

Regional gradient observability for semilinear hyperbolic systems： HUM approach

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Control Theory and Technology 2018年第1期16卷 72-80页

作者： Adil KHAZARI Ali BOUTOULOUT Imad EL HARRAKI Sidi Mohamed Ben Abdellah university Ecole Nationale de Commerce et de gestion Fez Morocco TSI Team MACS Laboratory Faculty of Sciences Moulay Ismail University Meknes Morocco ecole nationale superieure des mines de Rabat Rabat Morocco

The paper aims to extend the notion of regional observability of the gradient to the semilinear hyperbolic case, in order to reconstruct the gradient of the initial conditions in a subregion w of the domain evolution Ω. We start with an asymptotically linear system, the approach is based on an extension of the Hilbert uniqueness method （HUM） and Schauder＇s fixed point theorem. The analysis leads to an algorithm which is successfully numerically implemented and illustrated with examples and simulations.

关键词： Distributed systems fixed point regional gradient observability regional reconstruction semilinear hyperbolic systems

Layer-controlled nonlinear terahertz valleytronics in two-dimensional semimetal and semiconductor PtSe_(2)

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InfoMat 2023年第11期5卷 49-63页

作者： Minoosh Hemmat Sabrine Ayari Martin Micica Hadrien Vergnet Shasha Guo Mehdi Arfaoui Xuechao Yu Daniel Vala Adrien Wright Kamil Postava Juliette Mangeney Francesca Carosella Sihem Jaziri Qi Jie Wang Zheng Liu Jérôme Tignon Robson Ferreira Emmanuel Baudin Sukhdeep Dhillon Laboratoire de Physique de l'ecole normale supérieure ENSUniversitéPSLCNRSSorbonne UniversitéUniversitéde Paris-CitéParisFrance School of Materials Science and Engineering Nanyang Technological UniversitySingaporeSingapore Laboratoire de Physique de la Matière Condensée Département de PhysiqueFacultédes Sciences de TunisUniversitéTunis El ManarCampus UniversitaireTunisTunisia Key Laboratory of Multifunctional Nanomaterials and Smart Systems Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhouJiangsuthe People's Republic of China IT4Innovations National Supercomputing CenterVSB—Technical University of OstravaOstrava-PorubaCzech Republic Faculty of Materials Science and Technology VSB—Technical University of OstravaOstrava-PorubaCzech Republic School of Electrical and Electronic Engineering&School of Physical and Mathematical Sciences The Photonics InstituteNanyang Technological UniversitySingaporeSingapore

Platinum diselenide(PtSe_(2))is a promising two-dimensional(2D)material for the terahertz(THz)range as,unlike other transition metal dichalcogenides(TMDs),its bandgap can be uniquely tuned from a semiconductor in the nearinfrared to a semimetal with the number of atomic *** gives the material unique THz photonic properties that can be ***,we demonstrate that a controlled THz nonlinearity—tuned from monolayer to bulk PtSe_(2)—can be realized in wafer size polycrystalline PtSe_(2)through the generation of ultrafast photocurrents and the engineering of the bandstructure *** is combined with the PtSe_(2)layer interaction with the substrate for a broken material centrosymmetry,permitting a second order ***,we show layer dependent circular dichroism,where the sign of the ultrafast currents and hence the phase of the emitted THz pulse can be controlled through the excitation of different bandstructure *** particular,we show that a semimetal has a strong dichroism that is absent in the monolayer and few layer semiconducting *** microscopic origins of this TMD bandstructure engineering are highlighted through detailed DFT simulations,and shows the circular dichroism can be controlled when PtSe_(2)becomes a semimetal and when the K-valleys can be *** well as showing that PtSe_(2)is a promising material for THz generation through layer controlled optical nonlinearities,this work opens up a new class of circular dichroism materials beyond the monolayer limit that has been the case of traditional TMDs,and impacting a range of domains from THz valleytronics,THz spintronics to harmonic generation.

关键词： 2D transition metal dichalcogenides Dirac semimetal optical nonlinearities terahertz valleytronics

Identification of Glass Powders and Sands from the Crushing of Glass Waste from the City of Loméin Togo

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Open Journal of Civil Engineering 2022年第3期12卷 451-462页

作者： Apedjinou Dodji Kplolanyo Samah Essoavama Ouro-Djobo Amey Kossi Bollanigni Gbafa Kodjovi Senanou É quipe de Recherche en Mécanique (ERM) Ecole Nationale Supérieure d’Ingénieurs de l’Université de Lomé Lomé Togo Centre Régional de Formation pour l’Entretien Routier (Togo) (CERFER) Lomé Togo Equipe de Recherche et Développement de l’Institut FORMATEC Lomé Togo

The sustainability of a city depends on the effective and efficient management of its solid waste. Waste recycling channels mainly process glass bottles for direct reuse. Some of these sectors carry out the crushing and grinding of end-of-life glass waste for use in civil engineering without the identification in terms of building materials being clearly established. The present study therefore aims to determine the physical and chemical characteristics of glass powders and sands resulting from the crushing and grinding of glass waste from Grand Lomé in Togo in order to consider their granular potential. Samples of sand and glass powder from the crushing and grinding of white, brown and green glass were subjected to characterization tests in the laboratory followed by analysis of the granular parameters and their modeling by Weibull’s law. The results show that the powder and the glass sand contain a high proportion of silica (SiO2) ranging from 69.11% to 70.18% and a low proportion of alumina (Al2O3) (less than 0.07) and iron (Fe2O3) (lower to 1.09). These three materials have tight and male graded grain sizes (Cu Cc omogeneous (k density (2 dab depth study will be made to determine a suitable formula.

关键词： Glass Waste Granular Parameters Weibull’s Law Construction Materials