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Strength evolution and deformation behaviour of cemented paste backfill at early ages： Effect of curing stress, filling strategy and drainage

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International Journal of Mining Science and Technology 2016年第5期26卷 809-817页

作者： Ghirian Alireza fall Mamadou Department of Civil Engineering University of Ottawa 161 Louis Pasteur Ottawa K1N 6N5 ON Canada

In this study, a pressure cell apparatus is developed to investigate the early age evolution of the strength and deformation behaviour of cemented paste backfill(CPB) when subjected to various loading conditions under different curing scenarios. The different curing scenarios that are simulated include:(1)drained and undrained conditions,(2) different filling rates,(3) different filling sequences, and(4) different curing stresses. The findings show that drainage, curing stress, curing time and filling rate influence the mechanical and deformation behaviours of CPB materials. The coupled effects of consolidation, drainage and suction contribute to the strength development of drained CPB subjected to curing stress. On the other hand, particle rearrangement caused by the applied pressure and suction development due to self-desiccation plays a significant role in the strength gain of undrained CPB cured under ***, curing stress induces slightly faster rate of cement hydration, which can contribute to strength acquisition.

关键词： Cemented paste backfill Tailings Pore pressure Curing under stress Plug fill Cement

Chemically induced changes in the geotechnical response of cementing paste backfill in shaking table test

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第3期13卷 513-528页

作者： Imad Alainachi Mamadou fall Department of Civil Engineering University of OttawaOttawaOntarioK1N 6N5Canada

Cemented paste backfill(CPB)is extensively used for underground mine support and/or tailings ***,CPB behavior under cyclic loadings might be affected by the chemistry of its porewater,which often contains sulphate *** today,no studies have addressed the effect of sulphate on the response of CPB to cyclic loadings by using shaking table *** study presents new findings of assessing the effect of the sulphate in the pore water of CPB on its geotechnical response to cyclic loading by using shaking *** mixtures were prepared(with and without sulphate),poured into a flexible laminar shear box,cured to 4 h,and then exposed to cyclic loading using one-dimensional(1D)shaking *** parameters(*** water pressure,settlement,lateral deformation,acceleration,electrical conductivity,effective stress,and liquefaction susceptibility)were monitored or determined before,during,and after *** results indicate that the sulphate-bearing CPB cured to 4 h can be prone to liquefaction under the studied ***,sulphate-free CPB samples are resistant to *** results are expected to contribute to a better understanding of the effect of water chemistry on the cyclic behavior of CPB,consequently enhancing the cost-effective design of CPB structures.

关键词： Cemented paste backfill(CPB) Liquefaction Shaking table Tailings Mine Sulphate

A column study of the hydro-mechanical behavior of mature fine tailings under atmospheric drying

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International Journal of Mining Science and Technology 2017年第2期27卷 203-209页

作者： Anis Roshani Mamadou fall Kevin Kennedy Department of Civil Engineering University of OttawaOttawa KIN 6N5Canada

In this paper, the hydro-mechanical behavior and physical properties of mature fine tailings(MFT) under atmospheric drying are investigated through a column study. In the study, evaporation takes place in the development of suction in the upper parts of the column and increasing suction leads to higher strength in the tailings. After 5 days, the suction in the first lift is around 17 k Pa in the upper part of the *** a second lift is added, the first lift initially loses strength but over a 30 days' period, the strength is recovered to its prior value and suction in the second lift reaches 500 k Pa. The vane shear strength values show a substantial increase in the strength of the MFT after 30 days under atmospheric drying and drainage. The 90% strength found in the column exceeds the threshold(5 k Pa). The hydraulic-mechanical properties of the deposited tailings are closely coupled due to several mechanisms, such as evaporation,drainage, self-consolidation, suction and crack development. The findings of this study will provide a better understanding of the placement behavior of multiple lifts of MFT and thus contribute to reclamation design standards and reduce the use of dedicated disposal areas.

关键词： Tailings Oil sand Environment Drying Multi-lift deposition

Swelling ability and behaviour of bentonite-based materials for deep repository engineered barrier systems:Influence of physical,chemical and thermal factors

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第3期14卷 689-702页

作者： Mohammed Alzamel Mamadou fall Sada Haruna Department of Civil Engineering University of OttawaOttawaOntarioK1N 6N5Canada

Compacted bentonite-sand(B/S)mixtures have been used as a barrier material in engineered barrier systems(EBSs)of deep geological repositories(DGR)to store nuclear *** study investigates the individual and combined effects of different chemical compositions of deep groundwaters(chemical factor)at potential repository sites in Canada(the Trenton and Guelph regions in Ontario),heat generated in DGRs(thermal factor),dry densities and mass ratios of bentonite and sand mixtures(physical factors)on the swelling behavior and ability of bentonite-based *** this study,swelling tests are conducted on B/S mixtures with different B/S mix ratios(20/80 to 70/30),compacted at different dry densities(ρd=1.6-2 g/cm^(3)),saturated with different types of water(distilled water and simulated deep groundwater of Trenton and Guelph)and exposed to different temperatures(20℃-80℃).Moreover,scanning electron microscopy(SEM)analyses,mercury intrusion porosimetry(MIP)tests and X-ray diffractometry(XRD)analyses are carried out to evaluate the morphological,microstructural and mineralogical characteristics of the B/S *** test results indicate that the swelling potential of the B/S mixtures is significantly affected by these physical and chemical factors as well as the combined effects of the chemical and thermal factors.A significant decrease in the swelling capacity is observed when the B/S materials are exposed to the aforementioned groundwaters.A large decrease in the swelling capacity is observed for higher bentonite content in the ***,higher temperatures intensify the chemically-induced reduction of the swelling capacity of the B/S barrier *** decrease in the swelling capacity is caused by the chemical and/or microstructural changes of the *** results from this research will help engineers to design and build EBSs for DGRs with similar groundwater and thermal conditions.

关键词： Deep geological repository Engineered barrier Bentonite-sand materials Nuclear waste Swelling capacity Swelling strain

A multiphysics-viscoplastic cap model for simulating blast response of cemented tailings backfill

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第3期9卷 169-182页

作者： Gongda Lu Mamadou fall Liang Cui Civil Engineering Department University of Ottawa Ottawa ON Canada

Although a large number of previous researches have significantly contributed to the understanding of the quasi-static mechanical behavior of cemented tailings backfill,an evolutive porous medium used in underground mine cavities,very few efforts have been made to improve the knowledge on its response under sudden dynamic loading during the curing *** fact,there is a great need for such information given that cemented backfill structures are often subjected to blast loadings due to mine *** this study,a coupled thermo-hydro-mechanical-chemical(THMC)-viscoplastic cap model is developed to describe the behavior of cementing mine backfill material under blast loading.A THMC model for cemented backfill is adopted to evaluate its behavior and evolution of its properties in curing processes with coupled thermal,hydraulic,mechanical and chemical ***,the model is coupled to a Perzyna type of viscoplastic model with a modified smooth surface cap envelope and a variable bulk modulus,in order to reasonably capture the nonlinear and rate-dependent behaviors of the cemented tailings backfill under blast *** of the parameters required for the variable-modulus viscoplastic cap model were obtained by applying the THMC model to reproducing evolution of cemented paste backfill(CPB)properties in the curing ***,the behavior of hydrating cemented backfill under high-rate impacts can be evaluated under any curing time of *** validation results of the proposed model indicate a good agreement between the experimental and the simulated *** authors believe that the proposed model will contribute to a better understanding of the performance of hydrating cemented backfill under blasting,and also to practical risk management of backfill structures associated with such a dynamic condition.

关键词： Thermo-hydro-mechanical-chemical (THMC) coupling Multiphysics processes Tailings Paste backfill Cap model Blast

Development of novel Gemini-cholesterol analogues for retinoid-related orphan receptors

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Organic Chemistry Frontiers 2022年第6期9卷 1522-1530页

作者： Uxía Gómez-Bouzó Alioune fall Judit Osz Yagamare fall ORCID logo Natacha Rochel Hugo Santalla Departamento de Química Orgánica Facultade de QuímicaUniversity of VigoCampus Lagoas de Marcosende36310 VigoSpain Department of Integrative Structural Biology IGBMC-CNRS UMR7104-Inserm U9641rue Laurent Fries67400 IllkirchFrance

Retinoic-acid-related Orphan Receptors (RORs) regulate the maintenance of the circadian rhythm and immune response among others and are involved in increasing numbers of pathologies including autoimmune diseases, cancer and neurological disorders leading to huge interest in the development of ROR ligands. Here, we describe the synthesis of six novel Gemini cholesterol analogues and the binding mode of one of them to RORγ.

关键词： analogues synthesis numbers

Geotechnical characterization of peat-based landfill cover materials

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Journal of Rock Mechanics and Geotechnical Engineering 2016年第5期8卷 596-604页

作者： Afshin Khoshand Mamadou fall Faculty of Engineering K.N.Toosi University of Technology Department of Civil Engineering University of Ottawa

Natural methane （CH4） oxidation that is carried out through the use of landfill covers （biocovers） is a promising method for reducing CH4 emissions from landfills. Previous studies on peat-based landfill covers have mainly focused on their biochemical properties （e.g. CH4 oxidation capacity）. However, the utilization of peat as a cover material also requires a solid understanding of its geotechnical properties （thermal, hydraulic, and mechanical）, which are critical to the performance of any biocover. Therefore, the objective of this context is to investigate and assess the geotechnical properties of peat-based cover materials （peat, peat–sand mixture）, including compaction, consolidation, and hydraulic and thermal conductivities. The studied materials show high compressibility to the increase of vertical stress, with compression index （Cc） values ranging from 0.16 to 0.358. The compressibility is a function of sand content such that the peat–sand mixture （1：3） has the lowest Cc value. Both the thermal and hydraulic conductivities are functions of moisture content, dry density, and sand content. The hydraulic conductivity varies from 1.74 × 10^-9 m/s to 7.35 × 10^-9 m/s, and increases with the increase in sand content. The thermal conductivity of the studied samples varies between 0.54 W/（m K） and 1.41 W/（m K） and it increases with the increases in moisture and sand contents. Increases in sand content generally increase the mechanical behavior of peat-based covers; however, they also cause relatively high hydraulic and thermal conductivities which are not favored properties for biocovers.

关键词： Landfill Geotechnical engineering Landfill cover Peat Compaction Compressibility Hydraulic and thermal conductivity

FunHoP:Enhanced Visualization and Analysis of Functionally Homologous Proteins in Complex Metabolic Networks

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Genomics, Proteomics & Bioinformatics 2021年第5期19卷 848-859页

作者： Kjersti rise May-Britt Tessem Finn Drablos Morten B.Rye Department of Clinical and Molecular Medicine NTNU-Norwegian University of Science and TechnologyTrondheim NO-7491Norway Department of Circulation and Medical Imaging NTNU-Norwegian University of Science and TechnologyTrondheim NO-7491Norway Clinic of Surgery St.Olavs HospitalTrondheim University HospitalTrondheim NO-7491Norway

Cytoscape is often used for visualization and analysis of metabolic *** example,based on KEGG data,a reader for KEGG Markup Language(KGML)is used to load files into ***,although multiple genes can be responsible for the same reaction,the KGMLreader KEGGScape only presents the first listed gene in a network node for a given *** can lead to incorrect interpretations of the *** new method,FunHoP,shows all possible genes in each node,making the pathways more *** collapses all genes in a node into one measurement using read counts from *** that activity for an enzymatic reaction mainly depends upon the gene with the highest number of reads,and weighting the reads on gene length and ratio,a new expression value is calculated for the node as a *** expression at node level is then applied to the *** prostate cancer as model,we integrate RNA-seq data from two patient cohorts with metabolism data from *** we show that FunHoP gives more consistent pathways that are easier to interpret *** and documentation for running FunHoP can be found at https://***/kjerstirise/FunHoP.

关键词： Homologous proteins Metabolic network Pathway visualization and analysis RNA-seq KEGG Cytoscape

Quality Improvement Project in Dairy Industry for the National Direction of Nutrition in Senegal:LABS Case

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Quality Improvement Project in Dairy Industry for the Nation...

作者： Marieme Amith fall 山东大学

学位级别：硕士

The turn of the millennium marked the advent of market globalization and financial *** are increasingly open to a global competition where factors contributing to competitiveness such as quality,performance and on-time delivery play a key *** and stakeholders around the world are demanding that the product or service for which they have paid meets their specifications,meets their expectations;and that it operates as *** is then seen as the ability to meet consumer expectations at a cost and price,both "acceptable" to the project or company,and to the customer but everything starts with a good project quality management *** ensure an annual per capita consumption of 40 liters of milk,Senegal spends nearly CFAF 53 billion to import dairy *** actions undertaken to develop the local dairy sector have not yet produced the expected *** are the problem Dairies,which the number has significantly increased since 2000,process quantities of local milk under artisanal conditions that do not always meet hygiene and sanitation *** improvement of the quality because of the poor quality of the local manufacturer became urgent to face competitiveness and face to the actual situation of the *** 1s project quality often neglected?Well,it’s hard to manage things we don’t understand but not *** quality seems to be an esoteric concept to many project *** subject has a real interest for us,as we found the necessity to contribute to the resolution of the *** study will enable the local manufacturer to understand the strategic element of better quality;its importance through the industry and also in the management of their future *** well to understand the importance of a strong quality management as the key of success not only for the industry but mostly affect the performance of their future project in *** other words,to demonstrate that the absence of a quality ma

关键词：乳品企业质量改进营养品质