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Physico-Chemical Features of the Kpassa Reservoir, Northern Benin, with Emphasis on Its Trophic State: A Preliminary Study

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Journal of Environmental Protection 2016年第13期7卷 2067-2080页

作者： Ousmane Touré Boukari Daouda Mama Youssouf Abou moctar limam bawa Laboratory of Applied Hydrology Department of Hydrology and Integrated Management of Water Resources National Institute of Water University of Abomey-Calavi Abomey-Calavi Benin Laboratory of Ecology and Aquatic Ecosystem Management Department of Zoology Faculty of Sciences and Technics University of Abomey-Calavi Abomey-Calavi Benin Laboratory of Water Chemistry Department of Chemistry Faculty of Sciences University of Lomé Lomé Togo

This work presents recent data on the physico-chemical properties and the trophic status of Kpassa reservoir at eighteen locations from August 2014 to February 2015. Seventeen physico-chemical parameters were measured and data obtained were statistically analyzed. The descriptive statistics showed their variations (minima-maxima) as follows: pH (4.65 - 7.30), temperature (25.1°C - 29.9°C), dissolved oxygen (1 - 5.79 mg/L), oxydability (0.32 - 10.88 mg O2/L), electrical conductivity (55 - 77 μS/cm𕒵), TDS (76 - 94 mg/L), turbidity (15.70 - 274.40 NTU), transparency (0.24 - 1.55 m), suspended matter (3 - 92 mg/L), total phosphorus (0.25 - 1.90 mg/L), orthophosphate (0.08 - 0.61 mg/L), nitrate (undetected 5.50 mg/L), nitrite (undetected 0.79 mg/L), ammonia (undetected 0.36 mg/L), chlorophyll a (7.20 - 2334.6 μg/L), silica (4.34 - 15.67 mg/L) and N/P ratio (0.08 - 42.62). These parameters were mainly influenced by agricultural activities and climatic conditions. The restriction or the removal of the use of chemical fertilizers in agricultural activities in Kpassa reservoir basin was recommended. The highest values of Pearson and Spearman correlations were observed across TDS and conductivity (0.967;0.951), turbidity and oxydability (0.924;0.665), turbidity and chlorophyll a (0.884;0.663), turbidity and suspended matter (0.982;0.793), suspended matter and transparency (𕒴.781;𕒴.819), suspended matter and nitrate (𕒴.813;𕒴.839), suspended matter and oxydability (0.919;0.602) and suspended matter and chlorophyll a (0.879;0.656). Carlson’s trophic state index (TSI) values varied between 36 and 66 showing that Kpassa reservoir was eutrophic in August and mesotrophic to oligotrophic during the other months of the sampling period. ANOVA and Kruskal-Wallis test indicated that there were no significant differences between sampling stations.

关键词： Physico-Chemical Features Trophic State Kpassa Reservoir Okpara River Benin

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Role of Natural and Anthropogenic Influence on the Salinization of Groundwater from Basement Aquifers in the Middle Part of Mono River Basin, Togo

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Journal of Environmental Protection 2020年第12期11卷 1030-1051页

作者： Kossitse Venyo Akpataku Masamaéya D. T. Gnazou Gbandi Djanéyé-Boundjou limam moctar bawa Serigne Faye Laboratory of Applied Hydrology and Environment Faculty of Science University of Lomé Lomé Togo Department of Geology Faculty of Sciences and Techniques Cheikh Anta Diop University Dakar Senegal Department of Chemistry Faculty of Sciences and Techniques University of Kara Kara Togo

This study aimed to identify the role of natural and anthropogenic influence on geochemical processes controlling groundwater salinization in the middle portion of the Mono River basin, Togo. Multivariate statistical analysis, geochemical masse balance modeling, and conventional graphical methods were applied to the chemical dataset obtained from 110 groundwater samples collected during two campaigns (March-May 2011 and April 2014). The results showed that groundwater is predominantly fresh, acidic to circumneutral and mixed cations-HCO-3 water types. The proportion of ions (Na+, K+, Cl- and SO2-4) occurring ubiquitously in a saline environment increases substantially with TDS. Two factors, defined as natural and anthropogenic, account for 76.5% of the hydrochemical dataset variance. Based on the hierarchical cluster analysis, groundwater samples are classified into four clusters that corroborate the factor analysis results and illustrate different hydrochemical evolution stages along a topographically-driven groundwater flow path. The primary natural process contributing to cations and bicarbonate ions is the weathering of silicate minerals and possibly secondary carbonates by infiltrating water enriched with soil CO2 gas. Groundwater salinization indicators including Cl-, SO2-4 and NO-3, originate from potential sources such as human and animal wastes, agrochemicals, and deforestation. Thermodynamic equilibrium conditions ranged from saturation to oversaturation with respect to quartz, chalcedony, amorphous silica, calcite, dolomite, sepiolite, and talc. In con

关键词： Mono River Basin Groundwater Silicates Weathering Anthropogenic Contamination Salinization Togo

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Physicochemical and Microbiological Quality of Shallow Groundwater in Lomé, Togo

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Journal of Geoscience and Environment Protection 2020年第12期8卷 162-179页

作者： Kossitse Venyo Akpataku Masamaéya D. T. Gnazou Tse Yawo Agbefu Nomesi Phintè Nambo Komi Doni limam moctar bawa Gbandi Djaneye-Boundjou Laboratory of Applied Hydrology and Environment (Ex Laboratory of Water Chemistry) University of Lomé Lomé Togo Department of Chemistry Faculty of Sciences and Techniques University of Kara Kara Togo Agency of Water and Sanitation for Africa Office of Togo Lomé Togo

The present study aimed to assess the physicochemical and microbiological quality of shallow groundwater tapped by private boreholes for water sale in Togo’s most urbanized coastal areas. Ninety-six (96) groundwater samples were collected at the water sale points for chemical and microbiological analyses using standard methods. The results showed that groundwater is predominantly acidic with fresh and brackish water of Na-Cl type. High concentrations of dissolved inorganic nitrogen (NO3- , NH4+and NO2-) and permanganate indices indicating potential organic matter were found. Among the major ions, Na+ (46.9%), Cl- (51.0%) and NO3- (50.0%) present the highest percentages of unsuitable concentrations compared to WHO guidelines. These findings indicate the control of the natural impact of seawater and lagoon system and anthropogenic pollution from domestic and urban wastes on groundwater’s physicochemical quality. About 65% of groundwater samples did not comply with the drinking water guidelines for microbial indicators, including total mesophilic flora, thermotolerant coliforms, and sulfite-reducing anaerobes. The results showed the failure of sanitation and hygiene conditions around sampling points and fecal contamination from sewage, pit latrines, septic tanks, and refuse and waste disposal. The degradation of physicochemical quality is higher in the old and high-density built-up areas. Simultaneously, microbial contamination represents a high risk of contracting waterborne or hygiene-sanitation-related diseases in the whole study area. This study provides a global view of shallow groundwater’s physicochemical and microbiological quality in the study area. Limitations and suggestions for future research are d

关键词： Shallow Groundwater Saltwater Nitrate Fecal Contamination Lome-Togo

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Design of Dipoles for the RF Energy Harvesting System Dedicated to GSM Applications

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Energy and Power Engineering 2025年第1期17卷 1-12页

作者： Abdoul Karim Mbodji Mohamed El moctar Malang Kambaye Ousmane Dieme Department of Physics Applied of UFR-SAT University Gaston Berger Saint-Louis Senegal

Nowadays, we are witnessing an era marked by the autonomy of wireless devices and sensor networks without the aid of batteries. RF energy harvesting therefore becomes a promising alternative for battery dependence. This work presents the design of an RF energy harvesting system consisting mainly of a rectenna (antenna and rectification circuit) and an adaptation circuit. First of all, we designed two dipole type antennas. One operates in the GSM 900 MHz band and the other in the GSM 1800 MHz band. The performances of the proposed antennas are provided by the ANSYS HFSS software. Secondly, we proposed two rectification circuits in order to obtain conversion efficiencies at 0 dBm of 64% for the system operating at the frequency of 900 MHz and 37% for the system at the frequency of 1800 MHz RF-DC. The rectifiers used are based on Schottky diodes. For maximum transfer of power between the antenna and the rectification circuit, L-type matching circuits have been proposed. This rectifier offers DC voltage values of 806 mV for the circuit at the frequency of 900 MHz and 616 mV for the circuit at the frequency of 1800 MHz. The adaptation circuits are obtained by carrying out simulations on the ADS (Advanced Design System) software.

关键词： Rectenna Antenna RF-DC Conversion Schottky Diode Efficiency RF Energy Harvesting

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Critical Perturbation Results for a Mixed Boundary Value Problem

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Chinese Annals of Mathematics,Series B 2025年第1期 25-50页

作者： Azeb ALGHANEMI Hichem CHTIOUI moctar MOHAMEDEN Department of Mathematics King Abdulaziz University Sfax University Faculty of Sciences of Sfax

Abstract Let K be a given positive function on a bounded domain?of R~n,n≥*** authors consider a nonlinear variational problem of the form:■ u in?with mixed Dirichlet-Neumann boundary *** is a non-compact variational problem,in the sense that the associated energy functional J fails to satisfy the Palais-Smale *** generates concentration and blow-up *** studying the behaviors of non-precompact flow lines of a decreasing pseudogradient of J,they characterize the points where blow-up phenomena occur,the so-called critical points at *** a characterization combined with tools of Morse theory,algebraic topology and dynamical system,allow them to prove critical perturbation results under geometrical hypothesis on the boundary part in which the Neumann condition is prescribed.

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Management of Congenital Disorders in a Resource-Limited Country: Organizational Model of a Specialized Working Group within a Perinatal Network

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Open Journal of Obstetrics and Gynecology 2025年第1期15卷 10-20页

作者： Mame Diarra Ndiaye Lissoune Cisse Daouda Ndour Yaye Joor Dieng Hélène Chami Mamadou Mour Traore Maguette Mbaye Pape moctar Faye Dalal Jamm National Hospital Center Dakar Senegal Cheikh Anta Diop University of Dakar Dakar Senegal Pikine National Hospital Center Dakar Senegal Albert Royer Childrens Hospital Dakar Senegal

Objective: To evaluate the organizational model of a perinatal network and its relevance in a resource-limited country. Methodology: This was a mixed prospective qualitative and quantitative study conducted over a 2-year period, from January 1, 2022, to December 31, 2023. This study took place in Senegal, a country with limited resources and a weakness of hyperspecialized medical technical resources. There was no policy for the management of fetal malformations. The qualitative part was carried out through overt participant observation. The human resources and the organization of the perinatal network were described. For the quantitative part, all fetuses managed during the study period were included. The studied parameters related to neonatal care and outcomes. Qualitative variables were described using dispersion parameters, and quantitative variables were described using proportions. Results: The perinatal network includes several specialists across six hospitals. Of these hospitals, only one provided emergency pediatric surgery. The network included highly specialized human resources in prenatal diagnosis, congenital heart defects, pediatric surgery, anesthesia, and other medical specialties in perinatology. Advanced ultrasound was centralized by an obstetrician. The team decided on the follow-up methods, timing, and mode of delivery. The newborn was immediately transferred to the appropriate specialty. Over the 2-year period, 201 fetuses were managed. The rate of cesarean delivery was 76.3%. Neonatal mortality was 51.4%. Discussion: Centralizing care improves the quality of prenatal diagnosis and management of congenital defects. Mortality remains high when emergency surgery is not well available. This mortality is also due to the lack of a single center offering all perinatal care and so, the transfer of newborns. The cesarean rate increases due to underlying conditions and organizational factors. Conclusion: Public policies should prioritize the centralizatio

关键词： Congenital Disorders Perinatal Network Resource-Limited Country Antenatal Diagnosis Care Centralization

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An experimental investigation of transient cavitation control on a hydrofoil using hemispherical vortex generators

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Journal of Hydrodynamics 2021年第6期33卷 1139-1147页

作者： Ebrahim Kadivar Takaho Ochiai Yuka Iga Ould el moctar Ship Technology Ocean Engineering and Transport SystemsUniversity of Duisburg-EssenDuisburgGermany Institute of Fluid Scienece Tohoku UniversitySendaiJapan

Unsteady cavitation causes noise,damage,and performance decline in the marine engineering and fluid machinery ***,finding a method to control the cavitation and its destructive effects is important for the industrial *** this work,we proposed a passive method to control the unsteady behavior of transient cavitation at the medium Reynolds *** this aim,we performed an experimental study using a high-speed camera to analyze the effects of hemispherical vortex generators(VGs)on the cavitation dynamics around a hydrofoil *** addition,the pressure pulsations induced by the collapse of the cavity structures in the wake region of the hydrofoil were captured with a pressure transducer mounted on the wall downstream of the *** results showed that the instability behaviors of the cavity structures on the hydrofoil were mitigated using the proposed cavitation passive control *** addition,the pressure pulsations in the wake region of the hydrofoil were reduced *** can be concluded that the suppression of cavitation instabilities can improve the operating life and reliability of the marine and hydraulic systems.

关键词： Hydrodynamic cavitation cavitation passive control hemispherical vortex generators pressure pulsations high speed observation

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Study of Ground Deformation Caused by Underground Tunneling with Physical Model Test

Study of Ground Deformation Caused by Underground Tunneling ...

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作者： SANA moctar 绍兴文理学院

学位级别：硕士

隧道施工期间的地面变形主要是由施工产生的地层损失所引起的。本文首先利用Peck公式研究了双隧道施工过程中的地层变形,然后引入了物理模型试验,以模拟排水法在隧道施工过程中引起的地层损失。目的是模拟隧道施工过程中因地层损失引起... 详细信息

隧道施工期间的地面变形主要是由施工产生的地层损失所引起的。本文首先利用Peck公式研究了双隧道施工过程中的地层变形,然后引入了物理模型试验,以模拟排水法在隧道施工过程中引起的地层损失。目的是模拟隧道施工过程中因地层损失引起的地层沉降,探讨不同地层损失率下的变形规律。在第一部分中,从第一条隧道开挖过程中现场采集的监测数据中,采用Peck公式通过对称法获得第二条隧道的变形曲线。最后,使用叠加法获得最终曲线。对获得的各种曲线的分析表明,叠加法会出现较大的变形,其峰值位于隧道的中心。该方法适用性较好,可预测双隧道施工期间的变形。此外,为了更好地理解我们的研究,实验过程如下:首先建立物理模型,为其配备隧道模型,位移传感器,然后使用干燥的石英砂填充模型箱,最后通过排水法模拟隧道沉降过程。在模拟结束时获得的结果表明,影响地层沉降的直接因素都与地层的损失有关,此外,地层的表面和内部的沉降随地层损失的增加而增加。地层沉降槽的曲线呈正态分布,地层损失引起的地表下陷槽范围约为3d,地层内部沉降槽的宽度随深度的增加而减小。此外,定义了地层沉降槽的体积传递率,即地层沉降槽的体积与地层损失的比值,发现地层沉降槽的体积传递率与地层深度成反比,与地层损失率成正比。在地铁隧道施工中,地面变形是不希望发生的,也是不可避免的影响。因此,最好的选择是研究现象,以便更好地理解问题。对该物理模型的研究非常有启发性,因为它可以很好地理解地层损失的概念,定义不同变形速率下的地面变形并推导几种变形规律以预测隧道施工期间的沉降。

关键词：地层损失室内模型试验排液法沉降槽体

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Paleoarchean bedrock lithologies across the Makhonjwa Mountains of South Africa and Swaziland linked to geochemical,magnetic and tectonic data reveal early plate tectonic genes flanking subduction margins

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Geoscience Frontiers 2018年第3期9卷 603-665页

作者： Maarten de Wit Harald Furnes Scott MacLennan moctar Doucouré Blair Schoene Ute Weckmann Uma Martinez Sam Bowring AEON-ESSRI (Africa Earth Observatory Network-Earth Stewardship Science Research Institute) Nelson Mandela University Department of Earth Science & Centre for Geobiology University of Bergen Department of Geosciences Princeton University Department of Geosciences Nelson Mandela University Department Geophysics GFZ-German Research Centre for GeosciencesHelmholtz Centre GISCAPETOWN Earth Atmosphere and Planetary SciencesMassachusetts Institute of Technology

The Makhonjwa Mountains, traditionally referred to as the Barberton Greenstone Belt, retain an iconic Paleoarchean archive against which numerical models of early earth geodynamics can be tested. We present new geologic and structural maps, geochemical plots, geo- and thermo-chronology, and geophysical data from seven silicic, mafic to ultramafic complexes separated by major shear systems across the southern Makhonjwa Mountains. All reveal signs of modern oceanic back-arc crust and subductionrelated processes. We compare the rates of processes determined from this data and balance these against plate tectonic and plume related models. Robust rates of both horizontal and vertical tectonic processes derived from the Makhonjwa Mountain complexes are similar, well within an order of magnitude, to those encountered across modern oceanic and orogenic terrains flanking Western Pacific-like subduction zones. We conclude that plate tectonics and linked plate-boundary processes were well established by 3.2-3.6 Ga. Our work provides new constraints for modellers with rates of a 'basket' of processes against which to test Paleoarchean geodynamic models over a time period close to the length of the Phanerozoic.

关键词： Paleoarchean Barberton Greenstone Belt Onverwacht Suite Geologic bedrock and structural maps Geochemistry and geophysics Plate tectonics

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Assessing the impacts of climate change on water resources of a West African trans-boundary river basin and its environmental consequences (Senegal River Basin)

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Research in Cold and Arid Regions 2013年第1期5卷 140-156页

作者： Cheikh Bécaye Gaye moctar Diaw Raymond Malou Department of Geology Faculty of Sciences and Techniques University Cheikh Anta Diop BOX: 5005 Dakar Senegal

The Senegal River Basin （SRB） is a shared watershed in West Africa which includes regions （the upper basin, valley, and delta）, characterized by distinct environmental conditions. An important feature of the Senegal River flow volume historically was its in- ter-annual irregularity, which caused a major water resource constrain. This situation has been accentuated during the long-term drought （1969-1984） in the Sahel zone which highlights the vulnerability of food-producing systems to climate change and variability. SRB is undergoing fundamental environmental, hydrologic, and socioeconomic traxisitions and represents a good illustration of sensi- tivity to climatic variations and opportunities for adaptation. This paper aims to study water resources systems under stress from cfi- mate variability and change in the Senegal River Basin. The results show （1） through the compilation of available data, information and knowledge （sedimentological, climatical, geological, environmental, archeological, etc.）, the chronological consequences of cli- mate change during the past millennium in West Africa, and also （2） an analysis of the recent impacts and vulnerability to climate change in the SRB and finally （3） the adaptation strategies in the SRB in order to identify and resolve problems associated with this water scarcity and to address the potential for guaranteed agricultural production in this narrow geographic area.

关键词： Senegal River Basin water resources climate change consequences adaptation

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