The study carried out on the waters of the Méné River led to an overall assessment of its water quality during the dry season and the rainy season. The analysis focused on eight (8) water samples taken from ...The study carried out on the waters of the Méné River led to an overall assessment of its water quality during the dry season and the rainy season. The analysis focused on eight (8) water samples taken from the river during a period of dry season (January-February) and a period of rainy season (June and September). The various physicochemical parameters were measured according to Afnor standardized methods. The readings of temperature, turbidity, pH and conductivity made it possible to account for the disturbances occurring in water quality. A temporal variation correlated with the seasons (dry or rainy) is noted. Turbidity depends on the concentration of suspended solids (SS) in the water and drained particles and therefore on the seasons. Just like the temperature, the conductivity changes with the season. The waters of the Méné River are generally acidic. The results obtained show that there is a low level of pollution by chlorides, phosphates, nitrites and nitrates. A slight pollution of the waters of Méné in organic matter (chemical oxygen demand values are less than 25 mg∙L−1 during dry season and 32.33 ± 4.73 mg∙L−1 during rainy season) was observed. The concentrations of metallic trace elements such as iron, manganese and aluminum indicate significant pollution of these waters by these elements. Overall, the waters of the Méné River are of satisfactory quality because all the physicochemical parameters analyzed have values below standards during the dry season as well as during the rainy season with the exception of COD and a few metallic trace elements.展开更多
Malaria, a febrile human disease transmitted by female anopheles whose ecology is linked to water, is a major public health problem in Côte d’Ivoire, more precisely in the Marahoué region located in the...Malaria, a febrile human disease transmitted by female anopheles whose ecology is linked to water, is a major public health problem in Côte d’Ivoire, more precisely in the Marahoué region located in the southwest of the country. In order to effectively control this disease, it is necessary to understand the etiology and the diffusion pattern of the vectors. This justifies this study, which proposes to determine the areas at risk of malaria transmission in order to carry out an effective fight against this disease in this region of Côte d’Ivoire. To achieve this, a combined approach of geographic information systems and multicriteria analysis was adopted. The analysis reveals that the south and northwest of the Marahoué region present a high risk for malaria transmission. This risk is linked to indicators such as climatic factors that cover 48.36% of the study area, environmental factors such as vegetation cover (NDVI), soil moisture (NDWI), altitude, hydrography (water point) and population that covers 55.29% of the area and land use. Also, the results indicated that 50.70% of the region has favorable conditions for malaria transmission. Overall, climatic and environmental indicators are the risk factors associated with the resurgence of malaria.展开更多
This study aims to characterize the climatic variability in the South-East of Ivory Coast and to show its impact on the supply of water resources. To do this, statistical and hydrological methods were applied to clima...This study aims to characterize the climatic variability in the South-East of Ivory Coast and to show its impact on the supply of water resources. To do this, statistical and hydrological methods were applied to climatic data collected at the Marc DELORME Research Station of the CNRA. The statistical trend tests on this data revealed a significant decrease in precipitation and an increase in temperature, insolation and evaporation. Statistical break methods indicate a rainfall break in 1982 which marks a modification of the rainfall regime thus translating a drop in rainfall of 15%, a recession in the frequency of rainy days in general and in particular in rainfall heights between 10 and 30 mm and greater than 50 mm. This break is accompanied by a shortening of the rainy seasons, with average rainfall durations ranging from 54 days (short rainy season) to 104 days (great rainy season). Despite the disturbances in the different seasons of the year, the monthly rainfall regimes in the area have not changed. The assessment of the effects of drought on water resources using the Standardized Precipitation and Evapotranspiration Index (SPEI) for three-time scales (1 month, 3 months and 12 months) indicates a severe drought ranging from 3% to 7% over the period 1961 to 2018. However, despite the presence of this severe drought, the intensity of the drought was found to be moderate on all time scales. The Thorrnthwaite method was used to highlight the impacts of this climatic variability on the region’s water resources. The average annual recharge estimated at 402 mm, has been reduced to 153 mm during a deficit period, a decrease of about 62%. The average annual runoff, which was 294 mm, fells to 257 mm, a decrease of about 13%. This recorded decrease in the water infiltrated after the rainfall break (1983-2018), explains the heterogeneous decrease in the depth of the water table.展开更多
Marahoué watershed, located in the Center West of Côte d’Ivoire, has experienced significant population growth in recent decades. And a major economic boom linked to intense agricultural activity and th...Marahoué watershed, located in the Center West of Côte d’Ivoire, has experienced significant population growth in recent decades. And a major economic boom linked to intense agricultural activity and the presence of certain industries. This population growth is also accompanied by seasonal water shortages. Hence it needs to better manage the basin’s groundwater, which is a permanent resource and more resistant than surface water to climatic hazards. The objective of this study is therefore to propose a conceptual model of hydrogeological flow for the sustainable exploitation of groundwater resources in the Marahoué watershed. The establishment of the conceptual model was carried out in two stages. The first step consisted in defining the stratigraphic units. For this purpose, three units have been defined. These are the layer of alterite, the useful fissured horizon and the sound basement. The thickness of the layer of alterite varies from 0 to 80 m with an average of 26 m. As for the useful fissured horizon, its thickness is between 43 and 46.5 with an average of 45 m. In addition, the roof of the basement presents a slightly uneven morphology with a North-West, South-East dip and the altitudes are between 150 and 390 m. The second step corresponds to the phase of determining the hydrodynamic parameters. During this phase, the crack porosity, the transmissivity, the conductivity, the storage coefficient, the hydrological balance and the piezometric map were determined. Indeed, these parameters (the crack porosity, the transmissivity, the conductivity and the storage coefficient) confirm not only the heterogeneity of the medium but that the cracked horizon is sufficiently porous to be assimilated to an equivalent continuous medium during the simulation.展开更多
In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evalu...In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evaluated.It is shown,that Pr^(3+)ions can substitute Ce^(4+)ones in the support lattice,thereby introducing a high population of oxygen vacancies,which act as active sites for CO_(2) chemisorption.Pr doping can also act to reduce the crystallite size of metallic Ni,thus promoting the active metal dispersion.Catalytic performance evaluation evidences the promoting effect of low Pr loadings(5 at%and 10 at%)towards a higher catalytic activity and lower CO_(2) activation energy.On the other hand,higher Pr contents negate the positive effects on the catalytic activity by decreasing the oxygen vacancy population,thereby creating a volcano-type trend towards an optimum amount of aliovalent substitution.展开更多
Climate change continues to pose a threat to the sustainability of water resources while, water need is increasing. In spite of the efforts made by the state authorities to build water infrastructure, a large majority...Climate change continues to pose a threat to the sustainability of water resources while, water need is increasing. In spite of the efforts made by the state authorities to build water infrastructure, a large majority of the population is not having access to drinking water. In this study, Water Evaluation and Planning (WEAP) model was used to model the current situation of water supply and demands, to create scenarios for future water demands and supply. The results show that, in contrast to the livestock sector, which has a zero DNS, huge deficits are observed in reference scenario. These unsatisfied demands (DNS) are dominated by deficits in rice irrigation. The analysis of the evolution of demand according to the growth scenarios has shown that the deficits already observed in the reference scenario will reach 100.45 × 10<sup>6</sup> m<sup>3</sup> in 2040. To mitigate the effects of such deficits, water management optimization measures have been proposed. Strengthening the water supply to urban centers from the creation of dams could considerably reduce the observed deficits. These results are an important decision support tool for sustainable water resource management in the Lobo watershed. However, these strategies to improve access to water depend on the government’s political will on water and economic opportunities.展开更多
本研究的主要目的是基于该区域现有的实时宽频带台站,研究地震预警系统(earthquake early warning system,EEWS)对潜在破坏性地震发出警告的可行性。研究区位于伊比利亚半岛(Iberian Peninsula)西南部的圣维森特角(Cape San Vicente,SV...本研究的主要目的是基于该区域现有的实时宽频带台站,研究地震预警系统(earthquake early warning system,EEWS)对潜在破坏性地震发出警告的可行性。研究区位于伊比利亚半岛(Iberian Peninsula)西南部的圣维森特角(Cape San Vicente,SV)和加的斯湾(Gulf of Cádiz,GC)。该区域历史地震有1755年里斯本(Lisbon)M_w8.5地震和1969年圣维森特角Mw7.8地震。本研究阐明了基于美国地质调查局(U.S. Geological Survey,USGS)的Earthworm工具,及由西班牙加泰罗尼亚地质制图研究所(Institut Cartogràfici Geològicde Catalunya,ICGC)进一步研究出的地震预警系统的设计、配置和产出结果。系统的主要功能是实时数据采集、处理(利用预先估算的峰值位移Pd和P波信号的卓越周期τc进行P波拾取、地震事件监测、地震震源定位和震级估算)、数据归档和地震预警发布。系统在完成一些模拟实验并获得最佳配置后进行运行。在运行的第一年内,该区域发生了一次有感地震。与国家地理研究所(Instituto Geográfico Nacional,IGN)地震目录相比较,定位和震级结果都相当好。对于大部分区域的预警时间都能达到几十秒,对于葡萄牙和西班牙南部沿海大部分区域来说,足以减轻由GC和SV地震所带来的损害。此系统的初步结果表明,该系统能可靠地、有效地用于伊比利亚西南部地区的可能性。展开更多
In a context of climate change and declining water resources, knowledge of low flow is essential. Present study deals with the spatial and temporal evolution of the streams low flow in Sassandra river. In the study, 1...In a context of climate change and declining water resources, knowledge of low flow is essential. Present study deals with the spatial and temporal evolution of the streams low flow in Sassandra river. In the study, 12 stations of the Sassandra sub-basins (Sassandra, N’zo, Lobo, and Davo) were selected according to the availability and quality of long-term data. Annual, monthly and daily low flow data from twelve hydrological stations of the Sassandra watershed were used and cover the period from 1970 to 2015. The methodology used is concerned with extracting the low flow data and analyzing and evaluating the trends (Mann-Kendall) and change-point (cumulate sum) of low flow data. Statistical tests are applied to the mean and variance of the low-flow series. The results of the statistical tests show more trends and change points on the mean than on the variance. Significant trends show an increase in low flow waters. The significant change point detected by the cumulative sums test generally occurs between 1990-2007. In addition, tributaries are more affected by significant trends and change point detection than Sassandra river.展开更多
The Lobo watershed is highly anthropogenic since it has become the main production area for cocoa and coffee in C?te d’Ivoire. It therefore seems important to quantify soil loss by water erosion in this region. The W...The Lobo watershed is highly anthropogenic since it has become the main production area for cocoa and coffee in C?te d’Ivoire. It therefore seems important to quantify soil loss by water erosion in this region. The Wischmeier modeling was used to model the main factors involved in erosive phenomena. Crosscutting of thematic maps and the application of the USLE formulas made possible to evaluate the erosion rate at the watershed scale in 1986 and 2014. Although soil is susceptible to erosion and erosivity is increased, the results indicate a growth in soil loss estimated at 90.12%. Some agroforestry efforts are still possible to help reducing those soil losses.展开更多
During the NERIES Project, an accelerometric database containing European digital information was developed. Besides event and station metadata, ground motion parameters, computed in a homogeneous manner, were assemb...During the NERIES Project, an accelerometric database containing European digital information was developed. Besides event and station metadata, ground motion parameters, computed in a homogeneous manner, were assembled： PGA, PGV, AI, TD, CAV, H1 and PSV（f,5%） （19,961 components, 2629 events, 547 stations）. Merging small and moderate magnitude events produced a unique database capable of providing important information such as： （i） Correlations between several ground motion parameters follow analogous trends as in previous worldwide datasets, with slight corrections. （ii） Although PGA attenuations with distance show great uncertainties, four recent GMPEs recommended for Europe fit quite well the central 50% data interval for the distance range 10 〈 R 〈 200 kin; outside these distances, they do not fit. （iii） Soil amplification ratios indicate that weak motion （low magnitudes and larger distances） shows larger amplification than strong motion （short distances and large magnitudes） as represented in UBC97 for the USA, but not in EC8 for Europe. （iv） Average spectral shapes are smaller than in the EC8. （v） Differences in amplification factors for PGA, PGV and HI for EC8 soil classes B and C, and differences in spectral shapes for these soil classes, indicate that EC8, Type 2 S-coefficient should be frequency dependent, as in UBC97.展开更多
文摘The study carried out on the waters of the Méné River led to an overall assessment of its water quality during the dry season and the rainy season. The analysis focused on eight (8) water samples taken from the river during a period of dry season (January-February) and a period of rainy season (June and September). The various physicochemical parameters were measured according to Afnor standardized methods. The readings of temperature, turbidity, pH and conductivity made it possible to account for the disturbances occurring in water quality. A temporal variation correlated with the seasons (dry or rainy) is noted. Turbidity depends on the concentration of suspended solids (SS) in the water and drained particles and therefore on the seasons. Just like the temperature, the conductivity changes with the season. The waters of the Méné River are generally acidic. The results obtained show that there is a low level of pollution by chlorides, phosphates, nitrites and nitrates. A slight pollution of the waters of Méné in organic matter (chemical oxygen demand values are less than 25 mg∙L−1 during dry season and 32.33 ± 4.73 mg∙L−1 during rainy season) was observed. The concentrations of metallic trace elements such as iron, manganese and aluminum indicate significant pollution of these waters by these elements. Overall, the waters of the Méné River are of satisfactory quality because all the physicochemical parameters analyzed have values below standards during the dry season as well as during the rainy season with the exception of COD and a few metallic trace elements.
文摘Malaria, a febrile human disease transmitted by female anopheles whose ecology is linked to water, is a major public health problem in Côte d’Ivoire, more precisely in the Marahoué region located in the southwest of the country. In order to effectively control this disease, it is necessary to understand the etiology and the diffusion pattern of the vectors. This justifies this study, which proposes to determine the areas at risk of malaria transmission in order to carry out an effective fight against this disease in this region of Côte d’Ivoire. To achieve this, a combined approach of geographic information systems and multicriteria analysis was adopted. The analysis reveals that the south and northwest of the Marahoué region present a high risk for malaria transmission. This risk is linked to indicators such as climatic factors that cover 48.36% of the study area, environmental factors such as vegetation cover (NDVI), soil moisture (NDWI), altitude, hydrography (water point) and population that covers 55.29% of the area and land use. Also, the results indicated that 50.70% of the region has favorable conditions for malaria transmission. Overall, climatic and environmental indicators are the risk factors associated with the resurgence of malaria.
文摘This study aims to characterize the climatic variability in the South-East of Ivory Coast and to show its impact on the supply of water resources. To do this, statistical and hydrological methods were applied to climatic data collected at the Marc DELORME Research Station of the CNRA. The statistical trend tests on this data revealed a significant decrease in precipitation and an increase in temperature, insolation and evaporation. Statistical break methods indicate a rainfall break in 1982 which marks a modification of the rainfall regime thus translating a drop in rainfall of 15%, a recession in the frequency of rainy days in general and in particular in rainfall heights between 10 and 30 mm and greater than 50 mm. This break is accompanied by a shortening of the rainy seasons, with average rainfall durations ranging from 54 days (short rainy season) to 104 days (great rainy season). Despite the disturbances in the different seasons of the year, the monthly rainfall regimes in the area have not changed. The assessment of the effects of drought on water resources using the Standardized Precipitation and Evapotranspiration Index (SPEI) for three-time scales (1 month, 3 months and 12 months) indicates a severe drought ranging from 3% to 7% over the period 1961 to 2018. However, despite the presence of this severe drought, the intensity of the drought was found to be moderate on all time scales. The Thorrnthwaite method was used to highlight the impacts of this climatic variability on the region’s water resources. The average annual recharge estimated at 402 mm, has been reduced to 153 mm during a deficit period, a decrease of about 62%. The average annual runoff, which was 294 mm, fells to 257 mm, a decrease of about 13%. This recorded decrease in the water infiltrated after the rainfall break (1983-2018), explains the heterogeneous decrease in the depth of the water table.
文摘Marahoué watershed, located in the Center West of Côte d’Ivoire, has experienced significant population growth in recent decades. And a major economic boom linked to intense agricultural activity and the presence of certain industries. This population growth is also accompanied by seasonal water shortages. Hence it needs to better manage the basin’s groundwater, which is a permanent resource and more resistant than surface water to climatic hazards. The objective of this study is therefore to propose a conceptual model of hydrogeological flow for the sustainable exploitation of groundwater resources in the Marahoué watershed. The establishment of the conceptual model was carried out in two stages. The first step consisted in defining the stratigraphic units. For this purpose, three units have been defined. These are the layer of alterite, the useful fissured horizon and the sound basement. The thickness of the layer of alterite varies from 0 to 80 m with an average of 26 m. As for the useful fissured horizon, its thickness is between 43 and 46.5 with an average of 45 m. In addition, the roof of the basement presents a slightly uneven morphology with a North-West, South-East dip and the altitudes are between 150 and 390 m. The second step corresponds to the phase of determining the hydrodynamic parameters. During this phase, the crack porosity, the transmissivity, the conductivity, the storage coefficient, the hydrological balance and the piezometric map were determined. Indeed, these parameters (the crack porosity, the transmissivity, the conductivity and the storage coefficient) confirm not only the heterogeneity of the medium but that the cracked horizon is sufficiently porous to be assimilated to an equivalent continuous medium during the simulation.
基金support of this work by the project“Development of new innovative low carbon energy technologies to improve excellence in the Region of Western Macedonia”(MIS 5047197)which is implemented under the Action“Reinforcement of the Research and Innovation Infrastructure”funded by the Operational Program“Competitiveness,Entrepreneurship and Innovation”(NSRF 2014-2020)co-financed by Greece and the European Union(European Regional Development Fund)。
文摘In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evaluated.It is shown,that Pr^(3+)ions can substitute Ce^(4+)ones in the support lattice,thereby introducing a high population of oxygen vacancies,which act as active sites for CO_(2) chemisorption.Pr doping can also act to reduce the crystallite size of metallic Ni,thus promoting the active metal dispersion.Catalytic performance evaluation evidences the promoting effect of low Pr loadings(5 at%and 10 at%)towards a higher catalytic activity and lower CO_(2) activation energy.On the other hand,higher Pr contents negate the positive effects on the catalytic activity by decreasing the oxygen vacancy population,thereby creating a volcano-type trend towards an optimum amount of aliovalent substitution.
文摘Climate change continues to pose a threat to the sustainability of water resources while, water need is increasing. In spite of the efforts made by the state authorities to build water infrastructure, a large majority of the population is not having access to drinking water. In this study, Water Evaluation and Planning (WEAP) model was used to model the current situation of water supply and demands, to create scenarios for future water demands and supply. The results show that, in contrast to the livestock sector, which has a zero DNS, huge deficits are observed in reference scenario. These unsatisfied demands (DNS) are dominated by deficits in rice irrigation. The analysis of the evolution of demand according to the growth scenarios has shown that the deficits already observed in the reference scenario will reach 100.45 × 10<sup>6</sup> m<sup>3</sup> in 2040. To mitigate the effects of such deficits, water management optimization measures have been proposed. Strengthening the water supply to urban centers from the creation of dams could considerably reduce the observed deficits. These results are an important decision support tool for sustainable water resource management in the Lobo watershed. However, these strategies to improve access to water depend on the government’s political will on water and economic opportunities.
文摘In a context of climate change and declining water resources, knowledge of low flow is essential. Present study deals with the spatial and temporal evolution of the streams low flow in Sassandra river. In the study, 12 stations of the Sassandra sub-basins (Sassandra, N’zo, Lobo, and Davo) were selected according to the availability and quality of long-term data. Annual, monthly and daily low flow data from twelve hydrological stations of the Sassandra watershed were used and cover the period from 1970 to 2015. The methodology used is concerned with extracting the low flow data and analyzing and evaluating the trends (Mann-Kendall) and change-point (cumulate sum) of low flow data. Statistical tests are applied to the mean and variance of the low-flow series. The results of the statistical tests show more trends and change points on the mean than on the variance. Significant trends show an increase in low flow waters. The significant change point detected by the cumulative sums test generally occurs between 1990-2007. In addition, tributaries are more affected by significant trends and change point detection than Sassandra river.
文摘The Lobo watershed is highly anthropogenic since it has become the main production area for cocoa and coffee in C?te d’Ivoire. It therefore seems important to quantify soil loss by water erosion in this region. The Wischmeier modeling was used to model the main factors involved in erosive phenomena. Crosscutting of thematic maps and the application of the USLE formulas made possible to evaluate the erosion rate at the watershed scale in 1986 and 2014. Although soil is susceptible to erosion and erosivity is increased, the results indicate a growth in soil loss estimated at 90.12%. Some agroforestry efforts are still possible to help reducing those soil losses.
文摘During the NERIES Project, an accelerometric database containing European digital information was developed. Besides event and station metadata, ground motion parameters, computed in a homogeneous manner, were assembled： PGA, PGV, AI, TD, CAV, H1 and PSV（f,5%） （19,961 components, 2629 events, 547 stations）. Merging small and moderate magnitude events produced a unique database capable of providing important information such as： （i） Correlations between several ground motion parameters follow analogous trends as in previous worldwide datasets, with slight corrections. （ii） Although PGA attenuations with distance show great uncertainties, four recent GMPEs recommended for Europe fit quite well the central 50% data interval for the distance range 10 〈 R 〈 200 kin; outside these distances, they do not fit. （iii） Soil amplification ratios indicate that weak motion （low magnitudes and larger distances） shows larger amplification than strong motion （short distances and large magnitudes） as represented in UBC97 for the USA, but not in EC8 for Europe. （iv） Average spectral shapes are smaller than in the EC8. （v） Differences in amplification factors for PGA, PGV and HI for EC8 soil classes B and C, and differences in spectral shapes for these soil classes, indicate that EC8, Type 2 S-coefficient should be frequency dependent, as in UBC97.
