Indiscriminate disposal of solid waste in dumpsites located within urban areas has proved to be a problem to nearby residents in most developing cities of the world, Freetown is no exception. Open dumps have environme...Indiscriminate disposal of solid waste in dumpsites located within urban areas has proved to be a problem to nearby residents in most developing cities of the world, Freetown is no exception. Open dumps have environmental safeguards;they can pose major public health threats and environmental effects in urban cities. Therefore, this paper presents the findings of a research carried out in Freetown municipal area in Sierra Leone to determine the environmental and health impacts of solid waste disposal at Granville Brook dumpsite on the surrounding human settlements. Data were collected from three hundred and ninety eight nearby dumpsite household residents (less than fifty metres) and two hundred and thirty three far away household residents (more than fifty metres) through the use of structured self-administered questionnaires. Interviews and personal observations were also used to collect some of the data. Descriptive statistics involving tables, graphs and figures were used to present and analyze the data. Results show that both nearby residents and far away residents suffered from related diseases such as malaria, chest pains, diarrhea and cholera, due to the location of the dumpsite closer to their settlements. As a result, this study highlights the need for the Freetown City Council to properly manage and relocate the dumpsite to a safe distance from all human settlements, and provide resettlement and environmental education programmes for all persons living less than fifty metres away from the dumpsite as interim measures.展开更多
The Mesoproterozoic rifts are developed in the Ordos Basin located in the western margin of the North China Plate.Based on the latest 3D seismic data and previous research results,this study intends to discuss the zon...The Mesoproterozoic rifts are developed in the Ordos Basin located in the western margin of the North China Plate.Based on the latest 3D seismic data and previous research results,this study intends to discuss the zonal differential deformation characteristics and genetic mechanism of the Mesoproterozoic rifts in the Ordos Basin.NE-trending rifts are developed in the Mesoproterozoic in the south-central Ordos Basin,the main part of which are located near the western margin of the North China Plate.NNW-trending rifts are developed in the north of the basin,while NW-NNW rifts in the Mesoproterozoic in Hangjinqi area.The genetic mechanism of the Mesoproterozoic rifts is related to regional extensional stress field,plate boundary conditions and internal preexisting structures.The main extensional stress direction strikes NWW-SSE(120°)in the western margin of the North China Plate,based on the forward rift trend of the northern Mesoproterozoic.In Hangjinqi area,the reactivation of the existing NWtrending Wulansu fault and NW-NW-trending Daolao fault,results in dextral shear stress field.The boundary between the western margin of the North China Plate and its adjacent plates forms a nearly NS-trending preexisting basement tectonic belt,which intersects with the NWW-SSE(120°)extensional stress at an acute angle of 60°.Therefore,the western margin of the North China Plate is formed by oblique normal faults under oblique extension.Due to the long time span of Columbia Supercontinent breakup(1.8e1.6 Ga),the oblique rift in the south-central Ordos Basin is formed under the continuous oblique extension at the western margin of the North China Plate.展开更多
Rice is the main staple food of the vast majority of Sierra Leoneans, eaten on a daily basis by almost every household in the country. Rice is the most important food crop widely grown by farmers across the country. A...Rice is the main staple food of the vast majority of Sierra Leoneans, eaten on a daily basis by almost every household in the country. Rice is the most important food crop widely grown by farmers across the country. Although much attention is now focused on rice production through the small holder commercialization programme (SHCP), less attention has been given to investigating the constraints faced by rice producers in the country. Also, as food insecurity continues to be a major development problem across the country, thereby undermining people’s health, productivity, and often their very survival;this study contributes to efforts to overcome the development challenges posed by food insecurity necessarily begin with accurate assessment of influential factors that constrained the production of the staple food, rice. The main objective of this study is therefore to analysis the factors that influence rice production in the country, and specifically examine the relationship between rice production and the price of rice as sold in the domestic market. The study used a log linear model with the quantity of rice produced as the dependent variable and the price of domestic rice, quantity of rice imported and price of imported rice as explanatory. Findings indicated that, domestic rice is more expensive than imported rice per ton, and this underscores the argument that, rice importation is undermining domestic rice production as a viable income generating activity. Also, almost all the people in the capital city which hosts about 70% of the total population of country prefer eating imported rice, since it is free from stones and other impurities. However, In order to control price and still increase rice production, the government should be able to purchase the rice from the farmers and then sell this rice to private retailers.展开更多
Rice is the main food for over 95 percent of the Sierra Leonean populace. It accounts for the largest portion of the agricultural GDP of the country. On the contrary, its cultivation has been shrinking over the past d...Rice is the main food for over 95 percent of the Sierra Leonean populace. It accounts for the largest portion of the agricultural GDP of the country. On the contrary, its cultivation has been shrinking over the past decades. Consequently, importation now becomes the main source of supplying the grain for local needs since its cultivation or production could no longer meet domestic request. The deterioration in the local cultivation of rice has had severe socio-economic implications such as higher consumer prices and balance of payment burden. Therefore, the main objective of this study is to evaluate the effect of price and other related nonprice policy intervention on rice cultivation in the country. The tools utilized for analyzing the problem comprise, a coefficient of protection analysis as well as a supply response analysis by means of a time series regression (for the period 1980-2011). Major limitations established negatively affecting rice output are price disincentives to cultivators, public expenditure and fertilizer consumption. From the above findings, rice cultivators should be accorded the necessary incentives to keep them more effective in the rice cultivation career. The food policy approach that had over the years depended on huge importation of rice should be reviewed in favor of domestic cultivation. Increasing local cultivation through a meaningful protection of cultivators can independently reduce the price of rice to the advantage of the final consumers. This study also recommends that public funds should be redirected away from rice import toward investments in its domestic cultivation.展开更多
The generation of solid waste has become an increasing environmental and public health problem, especially in developing countries. These problems associated with the generation of solid waste are part of social chang...The generation of solid waste has become an increasing environmental and public health problem, especially in developing countries. These problems associated with the generation of solid waste are part of social changes where households play an important role. Invariably, these social changes influence the size, structure and characteristics of given households. This paper presents the findings of a study carried out in Freetown municipal area in Sierra Leone to assess socioeconomic factors affecting household solid waste generation and composition in Freetown, Sierra Leone. Structured questionnaires were administered with respect to these socioeconomic factors in four (4) selected constituencies of the city. These are the most populated constituencies that generated 70% of the total quantity of solid waste in the city. Therefore, they are suitable samples of the study area. The rate of waste generation was determined by using door- to-door approach in five (5) selected households from each constituency through sorting and weighing of solid wastes respectively. The dependent variables were solid waste generation and composition, and the independent variables were family size, education, income levels among others. The data obtained were subjected to statistical analysis to determine relationships between independent variables and dependent variables through correlation. The results showed that the solid waste generation and composition in Freetown was significantly affected by average family size, employment status, monthly income, and number of room(s) occupied by households. In general, the paper adequately suggests new insights concerning the role of socioeconomic factors in affecting the generation and composition of household solid waste.展开更多
In-situ stress is a critical factor influencing the permeability of coal reservoirs and the production capacity of coalbed methane(CBM)wells.Accurate prediction of in-situ stress and investigation of its influence on ...In-situ stress is a critical factor influencing the permeability of coal reservoirs and the production capacity of coalbed methane(CBM)wells.Accurate prediction of in-situ stress and investigation of its influence on coal reservoir permeability and production capacity are significant for CBM development.This study investigated the CBM development zone in the Zhengzhuang area of the Qinshui Basin.According to the low mechanical strength of coal reservoirs,this study derived a calculation model of the in-situ stress of coal reservoirs based on the multi-loop hydraulic fracturing method and analyzed the impacts of initial fractures on the calculated results.Moreover,by combining the data such as the in-situ stress,permeability,and drainage and recovery data of CBM wells,this study revealed the spatial distribution patterns of the current in-situ stress of the coal reservoirs and discussed the impacts of the insitu stress on the permeability and production capacity.The results are as follows.(1)Under given fracturing pressure,longer initial fractures are associated with higher calculated maximum horizontal principal stress values.Therefore,ignoring the effects of the initial fractures will cause the calculated values of the in-situ stress to be less than the actual values.(2)As the burial depth increases,the fracturing pressure,closure pressure,and the maximum and minimum horizontal principal stress of the coal reservoirs in the Zhengzhuang area constantly increase.The average gradients of the maximum and minimum horizontal principal stress are 3.17 MPa/100 m and 2.05 MPa/100 m,respectively.(3)Coal reservoir permeability is significantly controlled by the magnitude and state of the current in-situ stress.The coal reservoir permeability decreases exponentially with an increase in the effective principal stress.Moreover,a low lateral pressure coefficient(less than 1)is associated with minor horizontal compressive effects and high coal reservoir permeability.(4)Under similar conditions,such as resource endowments,CBM well capacity is higher in primary structural coal regions with moderate paleotectonic stress modification,low current in-situ stress,and lateral pressure coefficient of less than 1.展开更多
文摘Indiscriminate disposal of solid waste in dumpsites located within urban areas has proved to be a problem to nearby residents in most developing cities of the world, Freetown is no exception. Open dumps have environmental safeguards;they can pose major public health threats and environmental effects in urban cities. Therefore, this paper presents the findings of a research carried out in Freetown municipal area in Sierra Leone to determine the environmental and health impacts of solid waste disposal at Granville Brook dumpsite on the surrounding human settlements. Data were collected from three hundred and ninety eight nearby dumpsite household residents (less than fifty metres) and two hundred and thirty three far away household residents (more than fifty metres) through the use of structured self-administered questionnaires. Interviews and personal observations were also used to collect some of the data. Descriptive statistics involving tables, graphs and figures were used to present and analyze the data. Results show that both nearby residents and far away residents suffered from related diseases such as malaria, chest pains, diarrhea and cholera, due to the location of the dumpsite closer to their settlements. As a result, this study highlights the need for the Freetown City Council to properly manage and relocate the dumpsite to a safe distance from all human settlements, and provide resettlement and environmental education programmes for all persons living less than fifty metres away from the dumpsite as interim measures.
文摘The Mesoproterozoic rifts are developed in the Ordos Basin located in the western margin of the North China Plate.Based on the latest 3D seismic data and previous research results,this study intends to discuss the zonal differential deformation characteristics and genetic mechanism of the Mesoproterozoic rifts in the Ordos Basin.NE-trending rifts are developed in the Mesoproterozoic in the south-central Ordos Basin,the main part of which are located near the western margin of the North China Plate.NNW-trending rifts are developed in the north of the basin,while NW-NNW rifts in the Mesoproterozoic in Hangjinqi area.The genetic mechanism of the Mesoproterozoic rifts is related to regional extensional stress field,plate boundary conditions and internal preexisting structures.The main extensional stress direction strikes NWW-SSE(120°)in the western margin of the North China Plate,based on the forward rift trend of the northern Mesoproterozoic.In Hangjinqi area,the reactivation of the existing NWtrending Wulansu fault and NW-NW-trending Daolao fault,results in dextral shear stress field.The boundary between the western margin of the North China Plate and its adjacent plates forms a nearly NS-trending preexisting basement tectonic belt,which intersects with the NWW-SSE(120°)extensional stress at an acute angle of 60°.Therefore,the western margin of the North China Plate is formed by oblique normal faults under oblique extension.Due to the long time span of Columbia Supercontinent breakup(1.8e1.6 Ga),the oblique rift in the south-central Ordos Basin is formed under the continuous oblique extension at the western margin of the North China Plate.
文摘Rice is the main staple food of the vast majority of Sierra Leoneans, eaten on a daily basis by almost every household in the country. Rice is the most important food crop widely grown by farmers across the country. Although much attention is now focused on rice production through the small holder commercialization programme (SHCP), less attention has been given to investigating the constraints faced by rice producers in the country. Also, as food insecurity continues to be a major development problem across the country, thereby undermining people’s health, productivity, and often their very survival;this study contributes to efforts to overcome the development challenges posed by food insecurity necessarily begin with accurate assessment of influential factors that constrained the production of the staple food, rice. The main objective of this study is therefore to analysis the factors that influence rice production in the country, and specifically examine the relationship between rice production and the price of rice as sold in the domestic market. The study used a log linear model with the quantity of rice produced as the dependent variable and the price of domestic rice, quantity of rice imported and price of imported rice as explanatory. Findings indicated that, domestic rice is more expensive than imported rice per ton, and this underscores the argument that, rice importation is undermining domestic rice production as a viable income generating activity. Also, almost all the people in the capital city which hosts about 70% of the total population of country prefer eating imported rice, since it is free from stones and other impurities. However, In order to control price and still increase rice production, the government should be able to purchase the rice from the farmers and then sell this rice to private retailers.
文摘Rice is the main food for over 95 percent of the Sierra Leonean populace. It accounts for the largest portion of the agricultural GDP of the country. On the contrary, its cultivation has been shrinking over the past decades. Consequently, importation now becomes the main source of supplying the grain for local needs since its cultivation or production could no longer meet domestic request. The deterioration in the local cultivation of rice has had severe socio-economic implications such as higher consumer prices and balance of payment burden. Therefore, the main objective of this study is to evaluate the effect of price and other related nonprice policy intervention on rice cultivation in the country. The tools utilized for analyzing the problem comprise, a coefficient of protection analysis as well as a supply response analysis by means of a time series regression (for the period 1980-2011). Major limitations established negatively affecting rice output are price disincentives to cultivators, public expenditure and fertilizer consumption. From the above findings, rice cultivators should be accorded the necessary incentives to keep them more effective in the rice cultivation career. The food policy approach that had over the years depended on huge importation of rice should be reviewed in favor of domestic cultivation. Increasing local cultivation through a meaningful protection of cultivators can independently reduce the price of rice to the advantage of the final consumers. This study also recommends that public funds should be redirected away from rice import toward investments in its domestic cultivation.
文摘The generation of solid waste has become an increasing environmental and public health problem, especially in developing countries. These problems associated with the generation of solid waste are part of social changes where households play an important role. Invariably, these social changes influence the size, structure and characteristics of given households. This paper presents the findings of a study carried out in Freetown municipal area in Sierra Leone to assess socioeconomic factors affecting household solid waste generation and composition in Freetown, Sierra Leone. Structured questionnaires were administered with respect to these socioeconomic factors in four (4) selected constituencies of the city. These are the most populated constituencies that generated 70% of the total quantity of solid waste in the city. Therefore, they are suitable samples of the study area. The rate of waste generation was determined by using door- to-door approach in five (5) selected households from each constituency through sorting and weighing of solid wastes respectively. The dependent variables were solid waste generation and composition, and the independent variables were family size, education, income levels among others. The data obtained were subjected to statistical analysis to determine relationships between independent variables and dependent variables through correlation. The results showed that the solid waste generation and composition in Freetown was significantly affected by average family size, employment status, monthly income, and number of room(s) occupied by households. In general, the paper adequately suggests new insights concerning the role of socioeconomic factors in affecting the generation and composition of household solid waste.
基金sponsored by the National Natural Science Foundation of China(42002181)projecta public bidding project of 2020 Shanxi Provincial Science and Technology Program(20201101002-03).
文摘In-situ stress is a critical factor influencing the permeability of coal reservoirs and the production capacity of coalbed methane(CBM)wells.Accurate prediction of in-situ stress and investigation of its influence on coal reservoir permeability and production capacity are significant for CBM development.This study investigated the CBM development zone in the Zhengzhuang area of the Qinshui Basin.According to the low mechanical strength of coal reservoirs,this study derived a calculation model of the in-situ stress of coal reservoirs based on the multi-loop hydraulic fracturing method and analyzed the impacts of initial fractures on the calculated results.Moreover,by combining the data such as the in-situ stress,permeability,and drainage and recovery data of CBM wells,this study revealed the spatial distribution patterns of the current in-situ stress of the coal reservoirs and discussed the impacts of the insitu stress on the permeability and production capacity.The results are as follows.(1)Under given fracturing pressure,longer initial fractures are associated with higher calculated maximum horizontal principal stress values.Therefore,ignoring the effects of the initial fractures will cause the calculated values of the in-situ stress to be less than the actual values.(2)As the burial depth increases,the fracturing pressure,closure pressure,and the maximum and minimum horizontal principal stress of the coal reservoirs in the Zhengzhuang area constantly increase.The average gradients of the maximum and minimum horizontal principal stress are 3.17 MPa/100 m and 2.05 MPa/100 m,respectively.(3)Coal reservoir permeability is significantly controlled by the magnitude and state of the current in-situ stress.The coal reservoir permeability decreases exponentially with an increase in the effective principal stress.Moreover,a low lateral pressure coefficient(less than 1)is associated with minor horizontal compressive effects and high coal reservoir permeability.(4)Under similar conditions,such as resource endowments,CBM well capacity is higher in primary structural coal regions with moderate paleotectonic stress modification,low current in-situ stress,and lateral pressure coefficient of less than 1.
