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Evaluation of the Living Conditions and Health Perceptions of Waste Electrical and Electronic Equipment Handlers in the Informal Sector in Dakar

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Occupational Diseases and Environmental Medicine 2024年第2期12卷 115-129页

作者： Robert Faomowe Foko Awa Ndong Marius Kedote Fatoumata Bah Absa Lam Cheikh Diop Aminata Toure Mathilde Cabral mamadou fall Laboratoire de Toxicologie et d’ Hydrologie Facult&#233 de M&#233decine Pharmacie et Odontostomalogie Universit&#233 Cheikh Anta Diop de Dakar Dakar S&#233n&#233gal Unité Mixte de Recherche d&#8217Exploration et de Diagnostic Unit&#233 de Formation et de Recherche des Sciences de la Sant&#233 Universit&#233 Iba Der Thiam de Thi&#232s Thi&#232s S&#233n&#233gal Institut Ré gional de Sant&#233 Publique Universit&#233 d&#8217Abomey-Calavi Ouidah B&#233nin

Electrical and electronic devices are becoming an increasingly important part of our society. In Africa, and in Senegal in particular, the handling and management of electronic and electrical equipment (EEE) that has reached the end of its life is mainly informal. This professional environment is characterized by the disintegration of the sector and the social heterogeneity that can be found there. The objective of this study is to assess the standard of living of electrical and electronic equipment waste handlers in the Dakar region, as well as their perception of their health. A survey was used to obtain information on sociodemographic background, living arrangements, perception of health status, and good practices to be implemented in case of work-related health problems. Life style, perception of general health and health problems were ranged as excellent, very good, good, average and poor. Informal recyclers in the Dakar region lived mainly in rooms and buildings as tenants (49.1%), or in family homes (48.4%) before starting this activity, and 51.2% continue to live in rooms and buildings as tenants compared to 41.4% who still live in a family home. The perception of health status ranged from poor to excellent, and 4.9% believe that they are limited in work due to a disability or health problem. Informal work is a heterogeneous phenomenon that makes research and policymaking particularly complex. There are several external factors within informal WEEE re-cyclers that can cause health problems or functional disability. However, the living conditions and the perception they have of their state of health are contradictory to the working conditions and the social environment to which they belong. A biomedical approach would consolidate these achievements by confirming or invalidating them.

关键词： E-Waste Informal Work Living Arrangements Health Perception Occupational Exposure

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Long-Term Impact of Acute Retinoic Acid Supplementation at the Young Age on Testicular Architecture of Wistar Albino Rats

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Advances in Reproductive Sciences 2024年第1期12卷 1-13页

作者： Mama Sy Racha Kamenda Ibondou Fatoumata Bah Robert Foko Ndiaga Diop Mame Vénus Abdoulaye Séga Cheikh Diop mamadou fall Oumar Faye Laboratory of Histology Embryology and Cytogenetics Faculty of Medecine Cheikh Anta Diop University Dakar Senegal

Introduction: Inappropriate and excess vitamin supplementation, particularly for vitamin A, is increasingly recognized as a public health problem in developed countries. On the other hand, blind supplementation of vitamin A, for children in developing countries is a subject of controversy in the literature. The crucial role of vitamin A in the process of spermatogenesis in adult rodents is well established, but only a few publications are consecrated to the long-term effect of vitamin A intake at a young age on testicular development and differentiation. Objectives: Our study aimed to evaluate the long-term effects of acute supplementation at an early age, in the post-natal period, on spermatogenesis and testicular trophicity at adult age. Material and Methods: Young Wistar Albinos rats of 22 days received an acute high dose of supplementation of vitamin A (retinyl palmitate). The control group, group 1, received only extra virgin olive oil, Group 2 a dose of 7000 IU/kg of retinyl palmitate, group 3, 14,000 IU/kg, and Group 4 a dose of 28,000 IU/kg. At 10 weeks of age, the testes’ testosterone levels were measured by ELISA. For histological assessment, sections were stained with Hematoxylin eosin, and the Johnsen score was used to evaluate spermatogenesis in the seminiferous tubules. Results: The average testicular weights of rats were significantly lower in group 4 (p < 0.05), and so was the testosterone level in the testis compared to the control group (p .01). Most of the seminiferous tubules were concerned by an arrest of spermatogenesis and the Johnsen score was decreased with a mean score of 5.96 ± 1.60 (p .001) in that Group. In Group 3, Johnsen’s score was significantly better than the one obtained with the control. Conclusion: We observed a negative effect in the long term with a high acute dose of supplementation of retinyl palmitate at a young age, on testicular development and differentiation. Despite a return to normal diet after that supplementation, d

关键词： Vitamin A Retinyl Palmitate Spermatogenesis Testis-Wistar Albino Rats

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Respiratory Flow Rates of Metal Welders Compared to a Population Not Exposed to Metal Welding Dust

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Open Journal of Respiratory Diseases 2024年第2期14卷 51-59页

作者： Robert Faomowe Foko Abdou Khadir Sow Awa Ba Mor Diaw Fatoumata Bah Mame Saloum Coly Absa Lam Cheikh Diop Aminata Toure Abdoulaye Ba Abdoulaye Samb Arame Mbengue Mathilde Cabral mamadou fall Laboratory of Toxicology and Hydrology Faculty of Medicine Pharmacy and Odontostomatology Cheikh Anta Diop University of Dakar Dakar-Fann Senegal Laboratory of Physiology and Functional Exploration Faculty of Medicine Pharmacy and Odontostomatology Cheikh Anta Diop University of Dakar Dakar-Fann Senegal Laboratory of Physiology and Functional Exploration Alioune DIOP University of Bambey Bambey Senegal Laboratory of Physiology UFR of Health Sciences Functional Exploration Department Thies Regional Hospital Center Thies Senegal

Background: The welding trade includes many industrial activities in both the formal and informal sectors. Workers in this professional environment do not have access to individual and collective means of protection adapted to the activity, which exposes them to the dust emitted during their activity and therefore contributes to increasing the risk of developing respiratory disorders in this population. Objective: Our study aimed to evaluate the ventilatory function of metal welders in the city of Dakar. Method: This was a comparative study based on the analysis of the spirometric parameters of metal welders working in the city of Dakar (Senegal) with those of a control group of the same kind, selected from the general population. Measurements of forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and maximum mid expiratory flow (MMEF) were measured. Results: A total of 75 men between the ages of 19 and 61 were recruited and divided into two groups (43 controls and 32 welders). The welding population had more frequent distal and central obstructions and pulmonary restriction compared to the control group. The metals most commonly used by welders were aluminum for welders who had an obstruction, while for those who had a restriction, iron was the most used metal. Signs of metal fever were frequently found in welders, especially those with ventilatory disorders. Conclusion: The prevalence of respiratory disorders observed is close to that observed in industrial environments, where exposure levels are the highest. The lack of personal protective equipment could also be a significant risk factor in the development of these disorders.

关键词： Welder Occupational Exposure Spirometric Disorder Metal Fever Dakar

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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

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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

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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

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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：力学行为大气干燥细尾矿干燥条件水力电梯配置强度值常压干燥

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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

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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

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Design and Implementation of Data Sovereignty and Interoperability for Data Exchange in Logistics through Data Space

Design and Implementation of Data Sovereignty and Interopera...

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作者： DialIo mamadou AIpha 临沂大学

学位级别：硕士

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