检索结果-南通市图书馆

Asian Pacific Journal of Tropical Biomedicine 2017年第4期7卷 347-351页

作者： rokhaya fall Saliou Ngom Dienaba Sall Mbacke Sembène Abdoulaye Samb Laboratory of Natural Products Department of ChemistryFaculty of Science and TechnologyCheikh Anta Diop University Center for the Development of Horticulture Senegalese Institute of Agricultural Research Laboratory of Entomology Department of Animal BiologyFaculty of Science and TechnologyCheikh Anta Diop University

Objective: To isolate and identify the compounds in the essential oils from the leaves of Callistemon viminalis(D.R.) and Melaleuca leucadendron(Linn.) collected in Dakar,***: The essential oils from the leaves of these two myrtaceaes were extracted by steam distillation and analyzed by gas chromatograph and gas chromatography–mass ***: A total of 34 constituents were identified in the oil of Callistemon viminalis and the major compounds were 1.8-cineole(58.12%), limonene(9.72%), a-terpineol(9.56%),geranial(6.02%), d-elemene(3.53%), myrcene(2.96%) and a-pinene(2.49%).For the essential oil of Melaleuca leucadendron, 43 constituents were identified, and 1.8-cineole(28.87%), epiglobulol(23.06%), a-pinene(12.22%), limonene(11.65%) and a-terpineol(7.06%) were major ***: Considering properties of the identified major compounds, essential oils of both studied myrtaceae could be used in the medicine field including the food, pharmaceutical and cosmetic industry.

关键词： Callistemon viminalis Melaleuca leucadendron Essential oil Chemical composition

Larvicidal activity of Neem oil and three plant essential oils from Senegal against Chrysodeixis chalcites(Esper, 1789)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2018年第1期8卷 67-72页

作者： Saliou Ngom Raimundo Cabrera Perez Ma Anta Mbow rokhaya fall Saliou Niassy Andreea Cosoveanu Serigne Mbacké Diop El Hadji Barka Ndiaye Moussoukhoye Diop Georges Lognay Institut Sénégalais de Recherches Agricoles Unidad de Fitopatologia Facultad de Biología Universidad de la Laguna Département de chimie Faculté des Sciences et Techniques Université Cheikh Anta Diop de Dakar Development University of Pretoria Gembloux Agro-Bio Tech Université de Liège Chimie Analytique Department Agro Bio Tech

Objective: To evaluate the insecticide, larvicidal and repellent activity of the essential oils from Callistemon viminalis, Melaleuca leucadendron, and Hyptis suaveolens against Chrysodeixis chalcites and to compare it with neem oil(Azadirachta indica). Methods: The essential oils of the leaves of these aromatiques plants were extracted by steam distillation and contacts tests were carried out. Results: Essential oils in ethanol from Callistemon viminalis showed a higher biological activity than the neem with 100% larval mortality at the concentration of 2 μg/m L for 6 h, 100% and 90% in ethanol from Melaleuca leucadendron and Hyptis suaveolens, respectively at the concentration of 4 μg/m L for 24 h. By inhalation, the essential oils from Melaleuca leucadendron and of Hyptis suaveolens were more effective with mortality rates of larvae 100% and 50% respectively at 2 μg/L air applied after 24 h. Nevertheless, the neem has shown to be a repulsive plant and anti-nutritional plant. A significant difference in the percentages of consumption between leaves treated with neem oil and the control samples was observed(Newman-Keuls test) except for Melaleuca leucadendron. Conclusions: The results of the study highlight remarkable biocide, properties of tested extracts, which provides important opportunities for the development of biopesticides.

关键词： Plant extracts Chemical constituents Insecticidal activity Chrysodeixis

COVID-19 and the Tipping of Households Into Poverty in Senegal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Relations and Diplomacy 2021年第7期9卷 289-305页

作者： rokhaya Cissé Soufianou Moussa Abdou Salam fall UniversitéCheikh Anta de Dakar DakarSenegal

Based on household data from the"Jàngandoo"education quality barometer collected from March to July 2019 and on the"COVID-19 and family"survey conducted in December 2020,this article compares the vulnerabilities faced by households before the pandemic and in the post-pandemic *** analysis variations in household living conditions and in their financial,food,health and educational vulnerabilities of Dakar,Diourbel,Tambacounda and Ziguinchor in *** benefit of social protection in the same regions was also *** appears that COVID-19 is a major shock that has led to a decline in household living conditions from several angles affecting human *** southern and eastern regions(Ziguinchor and Tambacounda)were more affected,while the regions of Dakar and Diourbel were less exposed to the consequences of the *** among regions persist,and COVID-19 has accentuated *** addition to health interventions,the actions that should be undertaken are in the area of developing autonomous territorial poles to break the dependence on other geographical areas.

关键词： COVID-19 Vulnerabilities Households Living Arrangements Senegal

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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