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Stabilization of Clay Soil for the Durability of Structures: Case Study of the Soils of the Locality of Zalimé, Commune of Zogbodomey in the Republic of Benin

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Open Journal of Civil Engineering 2023年第1期13卷 103-112页

作者： Koffi Judicaël Agbelele ernesto Cabral houehanou Abalo P’Kla Isaac Ai Dossou Houngan Comlan Aristide Higher Normal School of Technical Education (ENSET) National University of Sciences Technologies Engineering and Mathematics (UNSTIM) Abomey Benin Laboroty of Energy and Applied Mechanics (LEMA) Polytechnic School of Abomey-Calavi (EPAC) Abomey-Calavi Benin National Higher Institute of Industrial Technology (INSTI) National University of Science Technology Engineering and Mathematics (UNSTIM) Abomey Benin Polytechnic School of Lomé University of Lomé (UL) Lomé Togo Verechaguine AK Civil Engineering School (ESGC-VAK) Gbegamey Benin

Structures erected on swelling clay soils are subjected to several stresses which are at the origin of the premature deterioration of the infrastructures. The soils being supports for the works, the improvement of their weak characteristics with cotton fibers will not only increase the bearing capacities of these soils and the resolution of the environmental problem, by eliminating the CO2 produced by the burning of the stems after harvest. The objective of this study is to contribute to the improvement of the characteristics by cotton stalk powder of the swelling clay soils used as the foundation of the infrastructures in order to guarantee their durability. Identification and mechanical parameterization tests were carried out on raw soil samples taken at 1.5 meters deep and on samples improved with cotton stalk powder at different levels (3%, 6% and 10%). The results from the physical tests reveal that the soil studied is very plastic silt. As for the mechanical tests, it appears that by adding 3% cotton stalk powder to dry density which goes from 1.435 t/m3 compared to the control sample with a dry density of 1.50 t/m3;which reflects an improvement in the compaction characteristics of the soil studied. The dry densities are 1.445 t/m3 and 1.29 t/m3 for the samples improved with 6% and 10% cotton stalk powder.

关键词： Improvement Swelling Clay Cotton Stalk Powder Silt Dry Density

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Experiments and 3D DEM of Triaxial Compression Tests under Special Consideration of Particle Stiffness

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Geomaterials 2018年第4期8卷 39-62页

作者： Marx Ferdinand Ahlinhan ernesto houehanou Marius Bocco Koube Valery Doko Quirin Alaye Nicholas Sungura Edmond Adjovi National University of Sciences Technologies Engineering and Mathematics (UNSTIM) Abomey Republic of Benin University of Abomey Calavi Abomey Calavi Republic of Benin Harbin institute of Technology Harbin China Deutsche Bahn Hannover Germany

Discrete element modelling is commonly used for particle-scale modelling of granular or particulate materials. Developing a DEM model requires the determination of a number of micro-structural parameters, including the particle contact stiffness and the particle-particle friction. These parameters cannot easily be measured in the laboratory or directly related to measurable, physical material parameters. Therefore, a calibration process is typically used to determine the values for use in simulations of physical systems. This paper focuses on how to define the particle stiffness for the discrete element modelling in order to perform realistic simulations of granular materials in the case of linear contact model. For that, laboratory tests and numerical discrete element modelling of triaxial compression tests have been carried out on two different non-cohesive soils i.e. poorly graded fine sand and gap graded coarse sand. The results of experimental tests are used to calibrate the numerical model. It is found that the numerical results are qualitatively and quantitatively in good agreement with the laboratory tests results. Moreover, the results show that the stress dependent of soil behaviour can be reproduced well by assigning the particle stiffness as a function of the particle size particularly for gap graded soil.

关键词： Grain Size Dependent Stiffness Experiment Discrete Element Modelling Triaxial Compression Test Non-Cohesive Soils Materials

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Evaluation and Mastery of the Risks of Swelling of Clayey Soils of the Kho Depression in the South-Benin

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材料科学与工程（中英文A版） 2018年第4期8卷 166-172页

作者： Gérard L. Gbaguidi Aisse ernesto C. houehanou Yvette Tankpinou Kiki Koffi J. Agbelele Abalo P. Kla Gérard Degan Laboratory of Materials and Structures (LAMS) Cotonou Benin Laboratory of Energetics and Mechanics Applied (LEMA) (EPAC) UAC Abomey-Calavi Benin National University of Sciences Technologies Engineering and Mathematics (UNSTIM) Abomey Benin National School of Engineers (ENSI) University of Lome (UL) BP 1515 Lome Togo

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From single to combinatorial therapies in spinal cord injuries for structural and functional restoration

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Neural Regeneration Research 2025年第3期20卷 660-670页

作者： ernesto Doncel-Pérez Gabriel Guízar-Sahagún Israel Grijalva-Otero Hospital Nacional de Parapléjicos de Toledo Servicio de Salud de Castilla La Mancha(SESCAM)ToledoSpain Medical Research Unit for Neurological Diseases UMAE Hospital de EspecialidadesCentro Médico Nacional Siglo XXIIMSSCiudad de MéxicoMéxico

Spinal cord injury results in paralysis, sensory disturbances, sphincter dysfunction, and multiple systemic secondary conditions, most arising from autonomic dysregulation. All this produces profound negative psychosocial implications for affected people, their families, and their communities;the financial costs can be challenging for their families and health institutions. Treatments aimed at restoring the spinal cord after spinal cord injury, which have been tested in animal models or clinical trials, generally seek to counteract one or more of the secondary mechanisms of injury to limit the extent of the initial damage. Most published works on structural/functional restoration in acute and chronic spinal cord injury stages use a single type of treatment: a drug or trophic factor, transplant of a cell type, and implantation of a biomaterial. Despite the significant benefits reported in animal models, when translating these successful therapeutic strategies to humans, the result in clinical trials has been considered of little relevance because the improvement, when present, is usually insufficient. Until now, most studies designed to promote neuroprotection or regeneration at different stages after spinal cord injury have used single treatments. Considering the occurrence of various secondary mechanisms of injury in the acute and sub-acute phases of spinal cord injury, it is reasonable to speculate that more than one therapeutic agent could be required to promote structural and functional restoration of the damaged spinal cord. Treatments that combine several therapeutic agents, targeting different mechanisms of injury, which, when used as a single therapy, have shown some benefits, allow us to assume that they will have synergistic beneficial effects. Thus, this narrative review article aims to summarize current trends in the use of strategies that combine therapeutic agents administered simultaneously or sequentially, seeking structural and functional restoratio

关键词： neural regeneration neuroprotection spinal cord injury repair spinal cord injury treatments structural restoration of spinal cord injury

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Self-Organized Growth of Complex Nanotube Patterns on Crystal Surfaces

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Nano Research 2009年第10期2卷 743-754页

作者： ernesto Joselevich Department of Materials and Interfaces Weizmann Institute of ScienceRehovot 76100Israel

The organization of carbon nanotubes into well-dened straight or curved geometries and arrays on surfaces is a critical prerequisite for their integration into nanocircuits and a variety of functional *** review the recent development of a new approach to carbon nanotube organization based on self-organized growth directed by well-defined crystal surfaces,or“nanotube epitaxy”.We identify three different modes of surface-directed growth,namely by atomic rows,atomic steps,and *** emphasis is given here to the combinations of such surface-directed growth with external forces-like those exerted by an electriceld or gas o-wfor the creation of well-de-ned complex geometries,including crossbar architectures,serpentines,and coils.

关键词： Nanotubes self-organization surface science nanostructures nanofabrication self-assembly

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Study of geometric parameters for the design of short intakes with fan modelling

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Chinese Journal of Aeronautics 2022年第11期35卷 18-32页

作者： Andrea MAGRINI ernesto BENINI Dipartimento di Ingegneria Industriale Universitá degli Studi di PadovaPadova 35131Italy

The flow over a short intake is characterised by a strong interaction with the fan, that can only be captured when the rotor blades are modelled in the numerical simulations. In this paper, we use a coupled methodology to derive indications about relevant geometric variables affecting the high-incidence operation of an ultra-high bypass ratio turbofan intake with a length-to-diameter ratio of 0.35. By reproducing the effect of the fan through a body force model, we carry out a parametric study of the influence of the contraction ratio and the scarf angle at take-off conditions for a grid of 28 different three-dimensional shapes. The analysis of the selected performance metrics distributions at three angles of attack of 16., 24., and 28. reveals that a contraction ratio higher than 1.20 is needed to avoid separation at high incidence. While for an attached inlet the best performance is found with a moderate scarf angle, in presence of a developed separation the distortion level reduces as the scarf decreases up to negative values. We discuss the correspondence between the distortion indexes and the flow field, highlighting the origin of the detachment for the different geometries, according to the operating condition, and analysing the fan operation in the most distorted case. Finally, we assess the influence of modelling the rotor in the simulations, showing that its suppression effect on the separation at a given incidence depends on the intake geometric features.

关键词： Body force method Coupled methods Fan/intake interaction Nacelle aerodynamics Short intake UHBPR

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The plasma membrane calcium pump in the hearing process:physiology and pathology

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Science China(Life Sciences) 2011年第8期54卷 686-690页

作者： ernesto CARAFOLI Venetian Institute of Molecular Medicine University of Padova

Mammalian cells express four different plasma membrane Ca2+ *** of them(PMCA1 and PMCA4) are expressed ubiquitously,and are considered housekeeping ***(PMCA2 and PMCA4) have tissue restricted *** are abundantly expressed in the brain and in nervous tissue-derived cell *** primary transcripts of all PMCAs undergo alternative splicing,generating a large number of additional *** occurs at site A,in the N-terminal moiety of the pump,and at site C,within the C-terminal calmodulin binding domain:The pumps are canonical targets of calmodulin *** site C insertion leads to a truncation of the pump about 50 residues short of the original *** of the pumps(PMCA2) has special properties:It displays high activity even in the absence of the natural activator calmodulin,and has a particularly complex pattern of alternative splicing at both sites A and C.A variant of the PMCA2 pump containing an insert at site A and truncated C-terminally is the resident isoform of the pump in the stereocilia of hair cells of the inner *** exports Ca2+to the endolymph that bathes the stereocilia less efficiently than the full length,non-inserted PMCA2 *** proper functioning of hair cells demands the precise maintenance of the Ca2+balance between hair cells and the endolymph. Disturbances in the balance affect the process of mechano-electrical transduction,which depends on the ability of the stereo-ciliar bundle to deflect in response to sound *** tip links that organize the bundle are formed by the Ca2+binding pro-tein cadherin 23 and by protocadherin 15:Disturbances of the Ca2+binding by cadherin 23 and/or of the ability of the PMCA2 variant of the stereocilia to export Ca2+to the endolymph generate hearing loss *** phenotypes have now been described in mice and *** some cases they are linked to mutations of both cadherin 23 and the PMCA2 pump,but in other cases they may be generated by mutati

关键词： calcium ATPases PMCA2 hereditary deafness calmodulin hair cells

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Assessing the Environmental Impact of Extensive Beef Production in Grazing Lands of Argentina

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Phyton-International Journal of Experimental Botany 2024年第8期93卷 1943-1962页

作者： ernesto Viglizzo Florencia Ricard Instituto de Ciencias de la Tierra y Ambientales de La Pampa Consejo Nacional de Investigaciones Científicas y TécnicasSanta Rosa6300La PampaArgentina Universidad Austral Rosario2000Santa FeArgentina Secretaría de Ambiente y Cambio Climático del Gobierno de La Pampa Santa Rosa6300La PampaArgentina Facultad de Ciencias Exactas y Naturales Universidad Nacional de La PampaSanta Rosa6300La PampaArgentina

Because of environmental constraints,beef cattle was for more than a century the only viable farming option in the extensive semiarid and subhumid lands of Argentina and the main source of nutrients for humans as ***,a growing concern and criticism have risen today about its possible negative impact on the climate and the *** worries tend to affect current public opinions,national policies,and international *** on 40 beef cattle farms scattered across different semiarid and subhumid regions of Argentina,here we evaluated the impact of extensive cattle production on carbon,water,and nutrient ***-Cycle Assessment(LCA)and Land-Based Assessment(LBA)were the two approaches we used here to compare the environmental impact of beef *** the environmental footprint(EF)resulting from LCA expresses the impact per unit of food,the environmental balance(EB),derived from LBA,aims at quantifying the impact per unit of *** such,the EB considers both negative and positive impacts on the farm as an integrated *** standardized procedures,we evaluated EF and EB up to the farm gate,leaving aside delocalized post-farm impacts such as those of processing,packaging,and transportation that occur beyond the farm *** agreement with previous evidence,our results show that the EF tends to decrease as per-head production *** coefficients and statistical significance were the following for carbon(R=−0.574;p<0.01),water(R=−0.561;p<0.01),and N(R=−0.704;p<0.01)and Phosphorus(P)pollution(R=−0.802;p<0.01)*** the contrary,the EB seems to be highly sensitive,and as per-hectare beef production *** were the following for carbon emissions(CE:R=0.955;p<0.01),water consumption(WC:R=0.822;p<0.01),nitrogen excretion(NE:R=0.948;p<0.01)and phosphorus excretion(PE:R=0.945;p<0.01).What our results suggest is that the notion of EF is useful to evaluate the environmental impact in intensive beef

关键词： Beef production extensive cattle raising grazing conditions environmental impact assessment

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Probabilistic estimate of rock mass static and dynamic demands for underground excavation stabilisation

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第3期11卷 481-493页

作者： ernesto Villaescusa Alan Thompson Christopher Windsor Western Australia School of Mines Curtin UniversityLocked Bag 30KalgoorlieWA 6433Australia Alan Thompson Geotechnology Pty Ltd. 40B Windich StreetEsperanceWA 6450Australia

Excavation damage under high in situ stress depends largely upon the potential block size associated with any violent *** size and shape of the dynamic instability are largely controlled by the location,orientation and extent of the pre-existing geological discontinuities.A new methodology is presented in which the rock mass demand can be expressed in terms of the mass in tonnes of unstable rock that is ejected per unit area of the excavation surface where failure occurs.A probabilistic approach has been implemented to estimate the potential rock mass instabilities and their associated static and dynamic *** new methodology considers that the strain energy released by the rock mass during violent stress-driven failure is largely converted into kinetic energy of ejection for *** estimated dynamic demand has been favourably compared with observations of rock mass damage in a number of underground excavations.

关键词： Geological structures Probabilistic design Underground excavations High stresses Dynamic and static demands Deep mining

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Aldynoglia cells and modulation of RhoGTPase activity as useful tools for spinal cord injury repair

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Neural Regeneration Research 2016年第7期11卷 1043-1045页

作者： ernesto Doncel-Perez Manuel Nieto-Sampedro Grupo de Quimica Neuro-Regenerativa Hospital Nacional de Paraplejicos Servicio de Salud de Castilla La Mancha (SESCAM) Toledo Spain Grupo de Plasticidad Neural Instituto Cajal CSIC Madrid Spain

A combined approach in spinal cord injury （SCI） therapy is the modulation of the cellular and molecular processes involved in glial scarring. Aldaynoglial cells are neural cell precursors with a high capacity to differentiate into neurons, promote axonal growth, wrapping and myelination of resident neurons. These important characteristics of aldaynoglia can be combined with specific inhibition of the RhoGTPase activity in astroglia and microglia that cause reduction of glial proliferation, retraction of glial cell processes and myelin production by oligodendrocytes. Previously we used experimental central nervous system （CNS） injury models, like spinal cord contusion and striatal lacunar infarction and observed that administration of RhoGTPase glycolipid inhibitor or aldaynoglial cells, respectively, produced a significant gain of functional recovery in treated animals. The combined therapy with neuro-regenerative properties strategy is highly desirable to treat SCI for functional potentiation of neurons and oligodendrocytes, resulting in better locomotor recovery. Here we suggest that treatment of spinal lesions with aldaynoglia from new rospheres plus local administration of a RhoGTPase inhibitor could have an additive effect and promote recovery from SCI.

关键词： glial scar astrocyte microglia neurospheres aldaynoglia axonal growth myelination glycosideinhibitor

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