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LiToTac: An Interactive-Interface Software for Finite Element Analysis of Multiple Contact Dynamics

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Computer Modeling in Engineering & Sciences 2019年第1期118卷 111-137页

作者： Lei Peng Zhiqiang Feng Pierre Joli Christine Renaud School of mechanics and Engineering Southwest Jiaotong UniversityChengdu610031China laboratory of mechanics and energetics UniversitéParis-SaclayEvry91020France.

In order to investigate the mechanical behavior of systems with complex architecture and a large number of contacting bodies,a finite element software,named LiToTac,has been developed by using the object-oriented programming *** software,with an interactive graphical user interface,is able to handle highly non-linear problems including multiple contacts and large *** importantly,the contact detection based on a hybrid three-stages methodology can be performed automatically,which is more efficient than the common strategies of pre-defining contact zones in commercial FEM software like ANSYS,ABAQUS,*** addition,the contact solver in LiToTac is portable between dynamic and quasi-static codes and can accurately solve contact coupled with friction in a reduced *** numerical examples are carried out to illustrate the functionality and capacity of the software package.

关键词： Finite element software object-oriented programming automatic contact detection multiple contact dynamics.

Long-term experimental study on gravitational sedimentation of water aluminum oxide nanofluid at different volumetric concentrations

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International Journal of Sediment Research 2023年第3期38卷 303-315页

作者： Mario Misale Johan Augusto Bocanegra Annalisa Marchitto DIME-Department of mechanics Energetics Management and Transportation Thermal Engineering and Environmental Conditioning Division University of Genoa

The stability of nanofluids is critical in engineering applications. The sedimentation of the nanoparticles in the base fluid limits the stability of the nanofluid. By measuring the absorbance of a visible laser through water aluminum oxide nanofluids it is possible to observe the evolution of the sedimentation process. A simple experimental setup consisting of a thin closed test cavity（0.8 mm or 1.5 mm thickness）filled with nanofluid and a set of laser diodes-photodiodes pairs was used in the experiments to determine the absorbance and the local volumetric concentration. The evolution of the local volumetric concentration of the nanofluid was measured at 13 height positions along the test cavity. Five initial volumetric concentrations of aluminum oxide（Al2O3; 0.5%, 1.0%, 1.5%, 2.0%, 3.0% and 4.0%） were considered. Data and digital photos were acquired for a total time lapse of 260 days. The results were independent of the container thickness. The same general trend was consistent for all the initial volumetric concentrations, i.e., the sedimentation rate decreases in time. The time evolution of the volumetric concentration was compared with results from a modified Mason-Weaver model. The comparison was possible by setting a variable sedimentation velocity in the model, suggesting that the sedimentation is affected by the dynamics of nanoparticle clusters with diverse sizes produced by agglomeration.

关键词： Pure nanofluid Aluminum oxide Nanoscale alumina particles Colloid sedimentation Nanoparticle settling Mason–Weaver model

Radiative heat transfer and thermal characteristics of Fe-based oxides coated SiC and Alumina RPC structures as integrated solar thermochemical reactor

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Science China(Technological Sciences) 2018年第12期61卷 1788-1801页

作者： GUENE LOUGOU Bachirou SHUAI Yong PAN RuMing CHAFFA Gédéon AHOUANNOU Clément ZHANG Hao TAN HePing Key laboratory of Aerospace Thermophysics of Ministry of Industry and Information Technology Harbin Institute of Technology School of Energy Science and Engineering Harbin Institute of Technology laboratory of energetics and Applied mechanics (LEMA) Polytechnic College of Abomey-Calavi Abomey-Calavi University

This paper investigated radiative heat transfer and thermal characteristics of Fe-based oxides coated SiC and Alumina reticulated porous ceramic structures as integrated solar thermochemical ***-flux solar radiation absorption and axial temperature distribution in the ceramic foams reactor were analyzed by adopting surface-to-surface radiation model coupled to the P1approximation for radiation heat *** radiative heat transfer and thermal characteristics of different foam-type RPC structures,including SiC,CeO_2,FeAl_2O_4,NiFeAlO_4,Fe_3O_4/SiC,and NiFe_2O_4/SiC were *** mass flow rate and foam structural parameters,including the permeability,pore mean cell size,and extinction coefficients have significantly affected the axial temperature distribution,pressure drop,heat transfer,and fluid *** porous structure to the solar receiver could maximize the incorporation of redox powder in the reacting medium,lower the pressure drop,and enhance the thermal performance of the thermochemical reacting *** structure was the candidate materials in the case where more heat flux and high axial temperature distribution is ***,Fe-based oxide coated Al_2O_3structure could be considered regarding the heat transfer enhancement along with the catalyst activity of oxygen carriers for solar thermochemical reacting system performance.

关键词： solar thermochemical reactor reticulated porous ceramics heat transfer and fluid flow pore mean cell size permeability and pressure drop

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Control of Cold Atoms by Slow Waves in a Hollow Fibre

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Chinese Physics Letters 2001年第2期18卷 169-171页

作者： LI Dai-Jun LIU Xia-Ji HUANG Hu LI Shi-Qun WANG Yu-Zhu Department of Physics Tsinghua UniversityBeijing 100084 laboratory for Laser energetics University of RochesterRochesterNY 14623-1299 Shanghai Institute of Optics and Fine mechanics Chinese Academy of SciencesShanghai 201800

We propose that a slowly-moving standing wave can be used to manipulate the motion of an atomic wave packet in a hollow optical fibre.A cloud of cold atoms can follow the motion of such a slow *** evolution of an initial Gaussian atomic wave packet in the moving standing wave is calculated by numerically solving the Schrödinger *** calculation shows that by using a sufficiently strong field and by adjusting the velocity of the standing wave pattern,the motion of the atomic cloud can be controlled in a hollow fibre.

关键词： equation wave wave

Elaboration of a Road Material Based on Clayey Soil and Crushed Sand

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Fluid Dynamics & Materials Processing 2022年第6期18卷 1595-1605页

作者： H.G.R.Sekloka C.P.Yabi R.Cloots M.Gibigaye Group of Research in Energy and Environment from Materials(GREENMAT) LiègeBelgium laboratory of energetics and Applied mechanics(LEMA) CotonouBenin laboratory of Tests and Studies in Civil Engineering(L2EGC) AbomeyBenin

To contribute to the enhancement of unconventional local materials used for road construction,this study characterizes a crushed sand 0/5,a clayey soil and the litho-stabilized material without and with hydraulic binder and determines their use in accordance with some reference specifications(CEBTP 1984).It is shown that the different components are not usable alone in pavement ***,the plasticity index obtained for the clayey soil is 21%,a value higher than the imposed *** addition,the grading of the 0/5 crushed sand does not fit into the range proposed by CEBTP.A combination of these two(02)components is therefore considered to obtain a suitable material usable for the *** new material does not enter any class of the CEBTP lateritic *** order to be used in base layer,a treatment with hydraulic binder is carried out with the intention to improve its mechanical *** optimal dosage of hydraulic binder to achieve the desired mechanical performance is obtained by studying the evolution of the mechanical characteristics of the *** this treatment,the Bearing Ratio index of the mix increases from 37 to 223 for the optimal dosage and the dry compaction density decreases from 2.11 to 2.06 g/cm3 while the optimal water content increases from 9%to 10.1%.

关键词： Clayey sand crushed sand hydraulic binder road base

Analysis of CO_2 utilization into synthesis gas based on solar thermochemical CH_4-reforming

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Journal of Energy Chemistry 2019年第1期28卷 61-72页

作者： Bachirou Guene Lougou Yong Shuai Gédéon Chaffa Huang Xing Heping Tan Huibin Du School of Energy Science and Engineering Harbin Institute of Technology Key laboratory of Aerospace Thermophysics of MIIT Harbin Institute of Technology laboratory of energetics and Applied mechanics (LEMA) Polytechnic College of Abomey-Calavi Abomey-Calavi University College of Metallurgy and Energy North China University of Science and Technology College of Management and Economics Tianjin University

In this study, the solar thermochemical reactor performance for CO_2 utilization into synthesis gas(H_2+ CO) based on CH_4 reforming process was investigated in the context of carbon capture and utilization(CCU) technologies. The P1 radiation heat transfer model is adopted to establish the heat and mass transfer model coupled with thermochemical reaction kinetics. The reactor thermal behavior with direct heat transfer between gaseous reactant and products evolution and the effects of different structural parameters were evaluated. It was found that the reactor has the potential to utilize by ～60% of CO_2 captured with 40% of CH_4 co-fed into syngas(72.9% of H_2 and 27.1% of CO) at 741.31 k W/mof incident radiation heat flux. However, the solar irradiance heat flux and temperature distribution were found to significantly affect the reactant species conversion efficiency and syngas production. The chemical reaction is mainly driven by the thermal energy and higher species conversion into syngas was observed when the temperature distribution at the inner cavity of the reactor was more uniform. Designed a solar thermochemical reactor able to volumetric store concentrated irradiance could highly improve CCU technologies for producing energy-rich chemicals. Besides, the mixture gas inlet velocity, operating pressure and CO_2/CH_4 feeding ratio were crucial to determining the efficiency of CO_2 utilization to solar fuels. Catalytic CO_2-reforming of CH_4 to chemical energy is a promising strategy for an efficient utilization of CO_2 as a renewable carbon source.

关键词： Thermochemical reactor CO2 utilization Radiation flux and temperature distribution CH4-reforming Syngas

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Comparative study of energetic potential from anaerobic digestion and direct combustion of date palm wastes

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Clean Energy 2023年第4期7卷 747-754页

作者： Nabila Lahboubi Omar Kerrou Brahim Sarh Toufik Boushaki Veronica Belandria Yasser El Khattabi Hassan El Bari laboratory of Electronic Systems Information ProcessingMechanics and EnergeticsFaculty of Sciences KenitraUniversity Ibn Tofail KenitraKenitraMorocco Institute of Combustion AerothermalReactivity and Environment(ICARE)-CNRS UPR302145071 Orléans Cedex 2France

This work aims to evaluate the technical and environmental feasibility of converting date palm waste from a Moroccan oasis into *** this study,two different scenarios were *** first proposed scenario is the valorization of the date palm substrates using direct combustion(thermochemical conversion)to produce *** second proposed scenario is the valorization of the substrates using combined anaerobic digestion of the substrate and direct combustion of the *** this study,two different date palm wastes are:empty fruit bunch(EFB)and palm leaflet(PL).The experimental lower heating values of the digestates studied are 12.93 and 12.71 MJ/kg,*** results show that using Scenario 1,the estimated output energies for the EFB and PL waste were 1.13 and 1.17 MWh,*** Scenario 2,the EFB and PL output energies were 1.27 and 1.39 MWh,*** study revealed that the combined process is possible as an alternative way to produce ***,combining anaerobic digestion and direct combustion of lignocellulosic waste can contribute to reducing greenhouse gas emissions.

关键词： biomass date palm waste energy direct combustion anaerobic digestion digestate

Use of Additive Based on Non-Timber Forest Products for the Ecological Stabilization of Raw Earth:Case of the Parkia Biglobosa Nut and Vitellaria Paradoxa

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Journal of Renewable Materials 2023年第12期11卷 4143-4160页

作者： Bio Chéïssou Koto Tamou Jean-Michel Mechling Crespin Prudence Yabi Gildas EdjrossèF.Godonou Edmond Codjo Adjovi Mohamed Gibigaye AndréLecomte Nicolas Brosse L2EGC-laboratory of Studies and Tests in Civil Engineering University of SciencesTechnologyEngineeringand MathematicsAbomeyBenin IJL-Jean Lamour Institute University of LorraineNancyFrance LEMA-laboratory of energetics and Applied mechanics University of Abomey-CalaviAbomey-CalaviBenin LERMAB-Study and Research laboratory on Wood Material University of LorraineNancyFrance

The housing sector today uses elaborate materials such as cement,iron,sand,often prohibitively expensive and whose production generates a strong environmental impact(scarcity of resources,transport,greenhouse gas greenhouse,etc.).In order to meet the challenges of sustainable development,earth construction is experiencing a resurgence of interest these *** its many advantages,raw earth material has drawbacks,in particular its low mechanical resistance and its loss of geometric characteristics in the face of water,which slow down its *** part of this study,the mechanical characteristics and durability of raw earth were improved by using residual water from the processing of Parkia Biglobosa(nere)and Vitellaria Paradoxa(shea)nuts in order to optimize its use for the construction of modern *** this end,the decoctions resulting from the artisanal transformation of the nut of the Parkia Biglobosa into African mustard and of the Vitellaria Paradoxa into shea butter were added to the raw earth according to volume proportions of 25%,50%,75%and 100%of the aqueous solution to obtain the projected ***,mechanical characterization and durability tests were carried out on the composites *** results revealed that the decoctions of Vitellaria Paradoxa and Parkia Biglobosa improve the compressive strength of the material by up to 90%and 260%,***,these decoctions improved the resistance to water penetration of the 100%additive composite by 1.5 times for Vitellaria Paradoxa and 5 times for Parkia *** study shows that it is possible to use decoctions as raw earth stabilizers to build modern,ecological buildings at lower energy ***,more in-depth studies on surface wettability and long-term durability are planned to better characterize the geomaterial.

关键词： Raw earth organic additive adobe Vitellaria Paradoxa Parkia Biglobosa durability

Novel power capture optimization based sensorless maximum power point tracking strategy and internal model controller for wind turbines systems driven SCIG

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Frontiers in Energy 2019年第4期13卷 742-756页

作者： Ali EL YAAKOUBI Kamal ATTARI Adel ASSELMAN Abdelouahed DJEBLI Optic and Photonic Tcam Faculty of SciencesAbdelmalek Essaaidi UniversityTetouan 93002Morocco energetics Fluid Mechanics and Materials LaboratoryAbdelmalek Essaadi UniversityTetouan 93002Morocco

Under the trends to using renewable energy sources as alternatives to the traditional ones,it is important to contribute to the fast growing development of these sources by using powerful soft computing *** this context,this paper introduces a novel structure to optimize and control the energy produced from a variable speed wind turbine which is based on a squirrel cage induction generator(SCIG)and connected to the *** optimization strategy of the harvested power from the wind is realized by a maximum power point tracking(MPPT)algorithm based on fuzzy logic,and the control strategy of the generator is implemented by means of an internal model(IM)*** IM controllers are incorporated in the vector control technique,as an alternative to the proportional integral(PI)controller,to implement the proposed optimization *** MPPT in conjunction with the IM controller is proposed as an alternative to the traditional tip speed ratio(TSR)technique,to avoid any disturbance such as wind speed measurement and wind turbine(WT)characteristic *** on the simulation results of a six KW-WECS model in Matlab/Simulink,the presented control system topology is reliable and keeps the system operation around the desired response.

关键词： power optimization wind energy conversion system maximum power point tracking(MPPT) fuzzy logic internal model(IM)controller