Flame retardants in commercial products eventually make their way into the waste stream.Herein the presence of flame retardants in Norwegian landfills, incineration facilities and recycling sorting/defragmenting facil...Flame retardants in commercial products eventually make their way into the waste stream.Herein the presence of flame retardants in Norwegian landfills, incineration facilities and recycling sorting/defragmenting facilities is investigated. These facilities handled waste electrical and electronic equipment（WEEE）, vehicles, digestate, glass, combustibles, bottom ash and fly ash. The flame retardants considered included polybrominated diphenyl ethers（∑BDE-10） as well as dechlorane plus, polybrominated biphenyls, hexabromobenzene,pentabromotoluene and pentabromoethylbenzene（collectively referred to as ∑FR-7）. Plastic,WEEE and vehicles contained the largest amount of flame retardants（∑BDE-10： 45,000–210,000 μg/kg; ∑FR-7： 300–13,000 μg/kg）. It was hypothesized leachate and air concentrations from facilities that sort/defragment WEEE and vehicles would be the highest. This was supported for total air phase concentrations（∑BDE-10： 9000–195,000 pg/m^3 WEEE/vehicle facilities, 80–900 pg/m^3 in incineration/sorting and landfill sites）, but not for water leachate concentrations（e.g., ∑BDE-10： 15–3500 ng/L in WEEE/Vehicle facilities and 1–250 ng/L in landfill sites）. Landfill leachate exhibited similar concentrations as WEEE/vehicle sorting and defragmenting facility leachate. To better account for concentrations in leachates at the different facilities, waste-water partitioning coefficients, Kwastewere measured（for the first time to our knowledge for flame retardants）. WEEE and plastic waste had elevated Kwastecompared to other wastes, likely because flame retardants are directly added to these materials. The results of this study have implications for the development of strategies to reduce exposure and environmental emissions of flame retardants in waste and recycled products through improved waste management practices.展开更多
Nutrition plays an essential role in normal linear growth in children. Knowledge of the eating styles and dietary consumption of healthy short children from developed countries is scarce. The aim of this study was to ...Nutrition plays an essential role in normal linear growth in children. Knowledge of the eating styles and dietary consumption of healthy short children from developed countries is scarce. The aim of this study was to investigate the dietary patterns in idiopathic short stature （ISS） and relatively low weight children compared to children with normal stature and weight. This research is a case-control study of 86 pre-pubertal healthy children, mean age 5.9 ± 1.5 years. The study group comprised 43 ISS children; 43 age-matched children with normal stature and weight served as controls. Outcome measures included： dietary patterns and physical activity. The absolute daily average energy, protein and carbohydrate intake was significantly lower in the ISS children （P 〈 0.05）; after correcting for body surface area, no significant differences were found between groups. Intake of micronutrients calcium, iron, zinc, vitamin A and vitamin C, expressed as percentage from Recommended Dietary Allowance, was significantly lower in the ISS children （P 〈 0.05）, who had lower food responsiveness, higher satiety responsiveness, lesser enjoyment of food and were slower eaters （P 〈 0.001）. Physical activity was sedentary in both the ISS cases and controls. Our findings in healthy, pre-pubertal, relatively lean ISS children point to a distinct eating pattern with no alteration in physical activity. Understanding the differences in dietary intake and eating behaviors may be beneficial in the development of targeted nutritional intervention for lean ISS children.展开更多
The objective of this study is to seek solutions to reduce the impact of buildings on climate change and to promote the use of local bio-sourced or geo-sourced materials for sustainable construction. Different samples...The objective of this study is to seek solutions to reduce the impact of buildings on climate change and to promote the use of local bio-sourced or geo-sourced materials for sustainable construction. Different samples of raw earth from 3 sites were taken in the commune of Mlomp. Geotechnical tests showed that the raw earth samples from sites 2 and 3 have more clay fraction while site 1 contains more sand. The fact of integrating fibers from crushed palm leaves (Borassus aethiopum) (2%, 4% and 6%) into the 3 raw earth samples reduced the mechanical resistance to compression and traction of the 3 raw earths. The experimental results of thermal tests on samples of earth mixtures with crushed Palma leaf fibers show a decrease in thermal conductivity as well as thermal effusivity as the percentages increase (2%, 4% and 6%) of fibers in raw earth for the 3 sites. This shows that this renewable composite material can help improve the thermal insulation of building envelopes.展开更多
BACKGROUND Type 1 diabetes(T1D)contributes to altered lipid profiles and increases the risk of cardiovascular disease(CVD).Youth with T1D may have additional CVD risk factors within the first decade of diagnosis.AIM T...BACKGROUND Type 1 diabetes(T1D)contributes to altered lipid profiles and increases the risk of cardiovascular disease(CVD).Youth with T1D may have additional CVD risk factors within the first decade of diagnosis.AIM To examine risk factors for dyslipidemia in young subjects with T1D.METHODS Longitudinal and cross-sectional retrospective study of 170 young subjects with T1D(86 males;baseline mean age 12.2±5.6 years and hemoglobin A1c 8.4%±1.4%)were followed in a single tertiary diabetes center for a median duration of 15 years.Predictors for outcomes of lipid profiles at last visit(total cholesterol[TC],triglycerides[TGs],low-density lipoprotein-cholesterol[LDL-c],and highdensity lipoprotein-cholesterol[HDL-c])were analyzed by stepwise linear regression models.RESULTS At baseline,79.5%of the patients had at least one additional CVD risk factor(borderline dyslipidemia/dyslipidemia[37.5%],pre-hypertension/hypertension[27.6%],and overweight/obesity[16.5%])and 41.6%had multiple(≥2)CVD risk factors.A positive family history of at least one CVD risk factor in a first-degree relative was reported in 54.1%of the cohort.Predictors of elevated TC:family history of CVD(β[SE]=23.1[8.3],P=0.006);of elevated LDL-c:baseline diastolic blood pressure(DBP)(β[SE]=11.4[4.7],P=0.003)and family history of CVD(β[SE]=20.7[6.8],P=0.017);of elevated TGs:baseline DBP(β[SE]=23.8[9.1],P=0.010)and family history of CVD(β[SE]=31.0[13.1],P=0.020);and of low HDL-c levels:baseline DBP(β[SE]=4.8[2.1],P=0.022]).CONCLUSION Our findings suggest that elevated lipid profiles are associated with DBP and a positive family history of CVD.It is of utmost importance to prevent and control modifiable risk factors such as these,as early as childhood,given that inadequate glycemic control and elevation in blood pressure intensify the risk of dyslipidemia.展开更多
Pile foundations are still the preferred foundation system for high-rise structures in earthquake-prone regions.Pile foundations have experienced failures in past earthquakes due to liquefaction.Research on pile found...Pile foundations are still the preferred foundation system for high-rise structures in earthquake-prone regions.Pile foundations have experienced failures in past earthquakes due to liquefaction.Research on pile foundations in liquefiable soils has primarily focused on the pile foundation behavior in two or three-layered soil profiles.However,in natural occurrence,it may occur in alternative layers of liquefiable and non-liquefiable soil.However,the experimental and/or numerical studies on the layered effect on pile foundations have not been widely addressed in the literature.Most of the design codes across the world do not explicitly mention the effect of sandwiched non-liquefiable soil layers on the pile response.In the present study,the behavior of an end-bearing pile in layered liquefiable and non-liquefiable soil deposit is studied numerically.This study found that the kinematic bending moment is higher and governs the design when the effect of the sandwiched non-liquefied layer is considered in the analysis as opposed to when its effect is ignored.Therefore,ignoring the effect of the sandwiched non-liquefied layer in a liquefiable soil deposit might be a nonconservative design approach.展开更多
Pendjari Biosphere Reserve(PBR),a primary component of the W-Arly-Pendjari transboundary biosphere reserve,represents the largest intact wild ecosystem and pristine biodiversity spot in West Africa.This savannah ecosy...Pendjari Biosphere Reserve(PBR),a primary component of the W-Arly-Pendjari transboundary biosphere reserve,represents the largest intact wild ecosystem and pristine biodiversity spot in West Africa.This savannah ecosystem has long been affected by fire,which is the main ecological driver for the annual rhythm of life in the reserve.Understanding the fire distribution patterns will help to improve its management plan in the region.This study explores the fire regime in the PRB during 2001–2021 in terms of burned area,seasonality,fire frequency,and mean fire return interval(MFRI)by analysing moderate resolution imaging spectroradiometer(MODIS)burned area product.Results indicated that the fire season in the PBR extends from October to May with a peak in early dry season(November–December).The last two fire seasons(2019–2020 and 2020–2021)recorded the highest areas burned in the PBR out of the twenty fire seasons studied.During the twenty years period,8.2%of the reserve burned every 10–11 months and 11.5%burned annually.The largest part of the reserve burned every one to two years(63.1%),while 8.3%burned every two to four years,5.8%burned every four to ten years,and 1.9%burned every ten to twenty years.Only 1.3%of the entire area did not fire during the whole study period.Fire returned to a particular site every 1.39 a and the annual percentage of area burned in the PBR was 71.9%.The MFRI(MFRI<2.00 a)was low in grasslands,shrub savannah,tree savannah,woodland savannah,and rock vegetation.Fire regime must be maintained to preserve the integrity of the PBR.In this context,we suggest applying early fire in tree and woodland savannahs to lower grass height,and late dry season fires every two to three years in shrub savannah to limit the expansion of shrubs and bushes.We propose a laissez-faire system in areas in woodland savannah where the fire frequency is sufficient to allow tree growth.Our findings highlight the utility of remote sensing in defining the geographical and temporal patterns of fire in the PBR and could help to manage this important fire prone area.展开更多
This document deals with the thermal characterization of a building with a layer of straw above the high floor. In the current environmental context, in Senegal, buildings are the biggest consumers of energy. This is ...This document deals with the thermal characterization of a building with a layer of straw above the high floor. In the current environmental context, in Senegal, buildings are the biggest consumers of energy. This is due to the construction materials used. Almost of buildings in Senegal used concrete (cement + aggregates) as based material construction. Due to this, the buildings require air conditioning or artificial ventilation to ensure minimum comfort. In face of this situation, it becomes useful to propose methods for reducing this high energy consumption. In this work, we propose to add a layer of straw above the high floor of a building in Matam city (North Senegal). In this case, we designed and modeled one building of single room in which the walls are in briks and a concrete slab. A bale of straw is layered on this slab in order to determine its influence on the energy consumption of the building. This study shows that the straw has a strong influence on the energy consumption of a building and the slab + straw building is more energy efficient than the bare slab building.展开更多
In this article, we present the study of a double-pass air insulated by crushed millet stem mixed with gum arabic. The study is carried out based on mathematical models obtained by writing energy conservation laws in ...In this article, we present the study of a double-pass air insulated by crushed millet stem mixed with gum arabic. The study is carried out based on mathematical models obtained by writing energy conservation laws in the various components of the system, which made it possible to determine the evolution of the air temperature as a function of the length of the absorber and to make a comparison with the experimental results. After comparing the results obtained with those found in the literature, the influence of some physical and geometrical parameters on the performance of the solar thermal collector is presented.展开更多
The aim of this study was to assess the runoff amount from a catchment characterized by diverse land uses by using the Soil Conservation Service Curve Number(SCS-CN) method based on Curve Number(CN) defined for domina...The aim of this study was to assess the runoff amount from a catchment characterized by diverse land uses by using the Soil Conservation Service Curve Number(SCS-CN) method based on Curve Number(CN) defined for dominant homogeneous elementary sub-regions.The calculations employed the SCS-CN method,involving the division of the catchment in two homogeneous parts and determining the runoff amount.The obtained results were compared with the results provided by three other CN determination methods,i.e.the Hawkins function,the kinetics equation,and a complementary error function peak.The catchment is located in a mountain dominated by forest land cover.Empirical CN-Precipitation(CN_(emp)-P) data pairs were analyzed using the mentioned methods,and the highest quality score was achieved from model 1.The results suggest that dividing a catchment into two homogeneous areas and determining their separate CN parameters,used later on to calculate the runoff by means of the presented approach,could be an alternative to the standard methods.The described method is relatively easy,and as it does not require an adoption of numerous parameters,and it can be employed for designing hydraulic facilities.展开更多
This research was conducted in the framework of the feasibility study related to FOCUSED-Benin project, the 5</span><sup><span style="font-family:Verdana;">th</span></sup><sp...This research was conducted in the framework of the feasibility study related to FOCUSED-Benin project, the 5</span><sup><span style="font-family:Verdana;">th</span></sup><span style="font-family:Verdana;"> work package of the YES-PV NIG BEN project financed by the German Government through its Ministry of Research and High Education (BMBF). The FOCUSED Benin project’s major objective is to protect the environment through the utilization of solar energy for drying</span><span style="color:red;"> </span><span style="font-family:Verdana;">agricultural products and table salt harvesting. Salt is important in human daily life. It is used for conservation of food, softening water, industrial processes, road de-icing, food seasoning, etc. Seawater evaporation, salt mining, and salt brine are the major sources of salt production worldwide. However, in West Africa, particularly in Benin Republic, table salt is produced using methods that negatively impact the ecology of the mangrove. This study aimed at investigating the current status of salt production in Benin Republic, its impact on the mangrove and its related health issues. Field visits, meeting with associations of women salt producers in the co</span><span style="font-family:Verdana;">astal region of the country, allowed to quantify the number of women associations dealing with salt production, their difficulties, and the impacts on the m</span><span style="font-family:Verdana;">angrove. Salt is a seasonal activity and is produced from January to May. One kilogram salt production, along with health issues reported by salt producers, requires approximately 1</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">kg of firewood obtained by cutting down mangrove. Salt price varies from 250CFA </span><a name="_Hlk67640154"></a><span style="font-family:Verdana;">(€0.38) to 400FCFA (€0.61) per kg depending on the season. The women salt producers are not aware of the ecological consequences of mangrove destruction. Sources of firewood are becoming increasingly scarce and prices prohibitive. Sensitization is not efficient. An alternative method of harvesting salt by solar drying and new ideas for implementing this activity in a participatory approach w</span></span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> discussed with the different associations of salt producers.展开更多
Bananas and plantains production is an important income source for millions of small farmers. The increased demand for bananas and plantains on national and international market would justify its value chain developme...Bananas and plantains production is an important income source for millions of small farmers. The increased demand for bananas and plantains on national and international market would justify its value chain development. However, its value chain faces several constraints, of which production and marketing turn out to be the most important. This study aimed at determining and analyzing the constraints related to Bananas and Plantains value chain and showing the gaps between agroecological and agricultural practices used by farmers in southern Benin. Characterization was carried out on the seed production systems, agricultural practices, bananas and plantains production, fruit availability and commercialization constraints with farmers using individual and focus groups surveys. Bananas and plantains seedlings production and acquisition varied according to production areas. Their seedlings self-production was widespread in production areas and 26 cultivars have been identified as major. The availability of these cultivars varied across time and production areas. There were significant negative effects of agricultural practices on major banana pest’s presence. Bananas and plantains production was limited by 12 factors, from which banana plants fall related to the wind, lack of financial support to irrigate banana fields, climate changes, no availability of cultivable lands and low rainfall are revealed to be the most important. Regarding commercialization constraints, low sale prices and difficult access to markets were the most important. Better knowledge of bananas and plantains production systems would help to develop sustainable organic farming strategies to reduce the constraints identified.展开更多
Solar energy is a very abundant renewable energy source during the day. The solar energy received in a given point of the Earth is function of the time, the season and the latitude of the point. It has been proven tha...Solar energy is a very abundant renewable energy source during the day. The solar energy received in a given point of the Earth is function of the time, the season and the latitude of the point. It has been proven that the solar energy received in one day by our planet is thirty times higher than the annual global energy consumption. Africa is one of the sunniest continents of the world. Nowadays, solar energy is attracting particular attention in the implementation of the energy policies. This renewable source is a key solution to world energy problems, especially in the context of global warming. Niger is identified as among the sunniest zones of the World. Knowledge of solar potential is one of the crucial parameters to master for energy applications. In this study, continuous measurements (at intervals of 5 minutes over 24 hours) of solar radiation have been carried out on the site of the National Center of Solar Energy of Niamey. These measurements were taken using the pyranometers, allowed us to collect the values of the daily global sunshine on a horizontal plane and on an inclined plane of the years 2015 and 2016. The treatment and the exploitation of these data allowed us to determine the daily and monthly duration of sunshine, then the impact of the clouds and dust on the solar radiation, to evaluate the solar potential of the site and determine the variations of this solar potential as a function of time. The results showed that the solar potential was very favorable for many solar applications.展开更多
基金Funding was provided by the Research Council of Norway(WASTEFFECT,Grant 221440/E40additional support from FANTOM,Grant 231736/F20)Funding from European Union's Horizon 2020 Marie Sklodowska-Curie grant agreement No 734522(INTERWASTE)is also acknowledged
文摘Flame retardants in commercial products eventually make their way into the waste stream.Herein the presence of flame retardants in Norwegian landfills, incineration facilities and recycling sorting/defragmenting facilities is investigated. These facilities handled waste electrical and electronic equipment（WEEE）, vehicles, digestate, glass, combustibles, bottom ash and fly ash. The flame retardants considered included polybrominated diphenyl ethers（∑BDE-10） as well as dechlorane plus, polybrominated biphenyls, hexabromobenzene,pentabromotoluene and pentabromoethylbenzene（collectively referred to as ∑FR-7）. Plastic,WEEE and vehicles contained the largest amount of flame retardants（∑BDE-10： 45,000–210,000 μg/kg; ∑FR-7： 300–13,000 μg/kg）. It was hypothesized leachate and air concentrations from facilities that sort/defragment WEEE and vehicles would be the highest. This was supported for total air phase concentrations（∑BDE-10： 9000–195,000 pg/m^3 WEEE/vehicle facilities, 80–900 pg/m^3 in incineration/sorting and landfill sites）, but not for water leachate concentrations（e.g., ∑BDE-10： 15–3500 ng/L in WEEE/Vehicle facilities and 1–250 ng/L in landfill sites）. Landfill leachate exhibited similar concentrations as WEEE/vehicle sorting and defragmenting facility leachate. To better account for concentrations in leachates at the different facilities, waste-water partitioning coefficients, Kwastewere measured（for the first time to our knowledge for flame retardants）. WEEE and plastic waste had elevated Kwastecompared to other wastes, likely because flame retardants are directly added to these materials. The results of this study have implications for the development of strategies to reduce exposure and environmental emissions of flame retardants in waste and recycled products through improved waste management practices.
文摘Nutrition plays an essential role in normal linear growth in children. Knowledge of the eating styles and dietary consumption of healthy short children from developed countries is scarce. The aim of this study was to investigate the dietary patterns in idiopathic short stature （ISS） and relatively low weight children compared to children with normal stature and weight. This research is a case-control study of 86 pre-pubertal healthy children, mean age 5.9 ± 1.5 years. The study group comprised 43 ISS children; 43 age-matched children with normal stature and weight served as controls. Outcome measures included： dietary patterns and physical activity. The absolute daily average energy, protein and carbohydrate intake was significantly lower in the ISS children （P 〈 0.05）; after correcting for body surface area, no significant differences were found between groups. Intake of micronutrients calcium, iron, zinc, vitamin A and vitamin C, expressed as percentage from Recommended Dietary Allowance, was significantly lower in the ISS children （P 〈 0.05）, who had lower food responsiveness, higher satiety responsiveness, lesser enjoyment of food and were slower eaters （P 〈 0.001）. Physical activity was sedentary in both the ISS cases and controls. Our findings in healthy, pre-pubertal, relatively lean ISS children point to a distinct eating pattern with no alteration in physical activity. Understanding the differences in dietary intake and eating behaviors may be beneficial in the development of targeted nutritional intervention for lean ISS children.
文摘The objective of this study is to seek solutions to reduce the impact of buildings on climate change and to promote the use of local bio-sourced or geo-sourced materials for sustainable construction. Different samples of raw earth from 3 sites were taken in the commune of Mlomp. Geotechnical tests showed that the raw earth samples from sites 2 and 3 have more clay fraction while site 1 contains more sand. The fact of integrating fibers from crushed palm leaves (Borassus aethiopum) (2%, 4% and 6%) into the 3 raw earth samples reduced the mechanical resistance to compression and traction of the 3 raw earths. The experimental results of thermal tests on samples of earth mixtures with crushed Palma leaf fibers show a decrease in thermal conductivity as well as thermal effusivity as the percentages increase (2%, 4% and 6%) of fibers in raw earth for the 3 sites. This shows that this renewable composite material can help improve the thermal insulation of building envelopes.
基金The study was reviewed and approved by the Institutional Review Board at Rabin Medical Center,approval No.0075-17-RMC.
文摘BACKGROUND Type 1 diabetes(T1D)contributes to altered lipid profiles and increases the risk of cardiovascular disease(CVD).Youth with T1D may have additional CVD risk factors within the first decade of diagnosis.AIM To examine risk factors for dyslipidemia in young subjects with T1D.METHODS Longitudinal and cross-sectional retrospective study of 170 young subjects with T1D(86 males;baseline mean age 12.2±5.6 years and hemoglobin A1c 8.4%±1.4%)were followed in a single tertiary diabetes center for a median duration of 15 years.Predictors for outcomes of lipid profiles at last visit(total cholesterol[TC],triglycerides[TGs],low-density lipoprotein-cholesterol[LDL-c],and highdensity lipoprotein-cholesterol[HDL-c])were analyzed by stepwise linear regression models.RESULTS At baseline,79.5%of the patients had at least one additional CVD risk factor(borderline dyslipidemia/dyslipidemia[37.5%],pre-hypertension/hypertension[27.6%],and overweight/obesity[16.5%])and 41.6%had multiple(≥2)CVD risk factors.A positive family history of at least one CVD risk factor in a first-degree relative was reported in 54.1%of the cohort.Predictors of elevated TC:family history of CVD(β[SE]=23.1[8.3],P=0.006);of elevated LDL-c:baseline diastolic blood pressure(DBP)(β[SE]=11.4[4.7],P=0.003)and family history of CVD(β[SE]=20.7[6.8],P=0.017);of elevated TGs:baseline DBP(β[SE]=23.8[9.1],P=0.010)and family history of CVD(β[SE]=31.0[13.1],P=0.020);and of low HDL-c levels:baseline DBP(β[SE]=4.8[2.1],P=0.022]).CONCLUSION Our findings suggest that elevated lipid profiles are associated with DBP and a positive family history of CVD.It is of utmost importance to prevent and control modifiable risk factors such as these,as early as childhood,given that inadequate glycemic control and elevation in blood pressure intensify the risk of dyslipidemia.
基金The Ministry of Education,Government of India,for the financial assistance provided during the research work。
文摘Pile foundations are still the preferred foundation system for high-rise structures in earthquake-prone regions.Pile foundations have experienced failures in past earthquakes due to liquefaction.Research on pile foundations in liquefiable soils has primarily focused on the pile foundation behavior in two or three-layered soil profiles.However,in natural occurrence,it may occur in alternative layers of liquefiable and non-liquefiable soil.However,the experimental and/or numerical studies on the layered effect on pile foundations have not been widely addressed in the literature.Most of the design codes across the world do not explicitly mention the effect of sandwiched non-liquefiable soil layers on the pile response.In the present study,the behavior of an end-bearing pile in layered liquefiable and non-liquefiable soil deposit is studied numerically.This study found that the kinematic bending moment is higher and governs the design when the effect of the sandwiched non-liquefied layer is considered in the analysis as opposed to when its effect is ignored.Therefore,ignoring the effect of the sandwiched non-liquefied layer in a liquefiable soil deposit might be a nonconservative design approach.
基金partly supported by the Royal Belgian Institute of Natural Sciences (RBINS) under the CEBios Program in Benin.
文摘Pendjari Biosphere Reserve(PBR),a primary component of the W-Arly-Pendjari transboundary biosphere reserve,represents the largest intact wild ecosystem and pristine biodiversity spot in West Africa.This savannah ecosystem has long been affected by fire,which is the main ecological driver for the annual rhythm of life in the reserve.Understanding the fire distribution patterns will help to improve its management plan in the region.This study explores the fire regime in the PRB during 2001–2021 in terms of burned area,seasonality,fire frequency,and mean fire return interval(MFRI)by analysing moderate resolution imaging spectroradiometer(MODIS)burned area product.Results indicated that the fire season in the PBR extends from October to May with a peak in early dry season(November–December).The last two fire seasons(2019–2020 and 2020–2021)recorded the highest areas burned in the PBR out of the twenty fire seasons studied.During the twenty years period,8.2%of the reserve burned every 10–11 months and 11.5%burned annually.The largest part of the reserve burned every one to two years(63.1%),while 8.3%burned every two to four years,5.8%burned every four to ten years,and 1.9%burned every ten to twenty years.Only 1.3%of the entire area did not fire during the whole study period.Fire returned to a particular site every 1.39 a and the annual percentage of area burned in the PBR was 71.9%.The MFRI(MFRI<2.00 a)was low in grasslands,shrub savannah,tree savannah,woodland savannah,and rock vegetation.Fire regime must be maintained to preserve the integrity of the PBR.In this context,we suggest applying early fire in tree and woodland savannahs to lower grass height,and late dry season fires every two to three years in shrub savannah to limit the expansion of shrubs and bushes.We propose a laissez-faire system in areas in woodland savannah where the fire frequency is sufficient to allow tree growth.Our findings highlight the utility of remote sensing in defining the geographical and temporal patterns of fire in the PBR and could help to manage this important fire prone area.
文摘This document deals with the thermal characterization of a building with a layer of straw above the high floor. In the current environmental context, in Senegal, buildings are the biggest consumers of energy. This is due to the construction materials used. Almost of buildings in Senegal used concrete (cement + aggregates) as based material construction. Due to this, the buildings require air conditioning or artificial ventilation to ensure minimum comfort. In face of this situation, it becomes useful to propose methods for reducing this high energy consumption. In this work, we propose to add a layer of straw above the high floor of a building in Matam city (North Senegal). In this case, we designed and modeled one building of single room in which the walls are in briks and a concrete slab. A bale of straw is layered on this slab in order to determine its influence on the energy consumption of the building. This study shows that the straw has a strong influence on the energy consumption of a building and the slab + straw building is more energy efficient than the bare slab building.
文摘In this article, we present the study of a double-pass air insulated by crushed millet stem mixed with gum arabic. The study is carried out based on mathematical models obtained by writing energy conservation laws in the various components of the system, which made it possible to determine the evolution of the air temperature as a function of the length of the absorber and to make a comparison with the experimental results. After comparing the results obtained with those found in the literature, the influence of some physical and geometrical parameters on the performance of the solar thermal collector is presented.
基金Dean of the Faculty of Environmental Engineering and Land Surveying, University of Agriculture in Krakow, for financial support
文摘The aim of this study was to assess the runoff amount from a catchment characterized by diverse land uses by using the Soil Conservation Service Curve Number(SCS-CN) method based on Curve Number(CN) defined for dominant homogeneous elementary sub-regions.The calculations employed the SCS-CN method,involving the division of the catchment in two homogeneous parts and determining the runoff amount.The obtained results were compared with the results provided by three other CN determination methods,i.e.the Hawkins function,the kinetics equation,and a complementary error function peak.The catchment is located in a mountain dominated by forest land cover.Empirical CN-Precipitation(CN_(emp)-P) data pairs were analyzed using the mentioned methods,and the highest quality score was achieved from model 1.The results suggest that dividing a catchment into two homogeneous areas and determining their separate CN parameters,used later on to calculate the runoff by means of the presented approach,could be an alternative to the standard methods.The described method is relatively easy,and as it does not require an adoption of numerous parameters,and it can be employed for designing hydraulic facilities.
文摘This research was conducted in the framework of the feasibility study related to FOCUSED-Benin project, the 5</span><sup><span style="font-family:Verdana;">th</span></sup><span style="font-family:Verdana;"> work package of the YES-PV NIG BEN project financed by the German Government through its Ministry of Research and High Education (BMBF). The FOCUSED Benin project’s major objective is to protect the environment through the utilization of solar energy for drying</span><span style="color:red;"> </span><span style="font-family:Verdana;">agricultural products and table salt harvesting. Salt is important in human daily life. It is used for conservation of food, softening water, industrial processes, road de-icing, food seasoning, etc. Seawater evaporation, salt mining, and salt brine are the major sources of salt production worldwide. However, in West Africa, particularly in Benin Republic, table salt is produced using methods that negatively impact the ecology of the mangrove. This study aimed at investigating the current status of salt production in Benin Republic, its impact on the mangrove and its related health issues. Field visits, meeting with associations of women salt producers in the co</span><span style="font-family:Verdana;">astal region of the country, allowed to quantify the number of women associations dealing with salt production, their difficulties, and the impacts on the m</span><span style="font-family:Verdana;">angrove. Salt is a seasonal activity and is produced from January to May. One kilogram salt production, along with health issues reported by salt producers, requires approximately 1</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">kg of firewood obtained by cutting down mangrove. Salt price varies from 250CFA </span><a name="_Hlk67640154"></a><span style="font-family:Verdana;">(€0.38) to 400FCFA (€0.61) per kg depending on the season. The women salt producers are not aware of the ecological consequences of mangrove destruction. Sources of firewood are becoming increasingly scarce and prices prohibitive. Sensitization is not efficient. An alternative method of harvesting salt by solar drying and new ideas for implementing this activity in a participatory approach w</span></span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> discussed with the different associations of salt producers.
文摘Bananas and plantains production is an important income source for millions of small farmers. The increased demand for bananas and plantains on national and international market would justify its value chain development. However, its value chain faces several constraints, of which production and marketing turn out to be the most important. This study aimed at determining and analyzing the constraints related to Bananas and Plantains value chain and showing the gaps between agroecological and agricultural practices used by farmers in southern Benin. Characterization was carried out on the seed production systems, agricultural practices, bananas and plantains production, fruit availability and commercialization constraints with farmers using individual and focus groups surveys. Bananas and plantains seedlings production and acquisition varied according to production areas. Their seedlings self-production was widespread in production areas and 26 cultivars have been identified as major. The availability of these cultivars varied across time and production areas. There were significant negative effects of agricultural practices on major banana pest’s presence. Bananas and plantains production was limited by 12 factors, from which banana plants fall related to the wind, lack of financial support to irrigate banana fields, climate changes, no availability of cultivable lands and low rainfall are revealed to be the most important. Regarding commercialization constraints, low sale prices and difficult access to markets were the most important. Better knowledge of bananas and plantains production systems would help to develop sustainable organic farming strategies to reduce the constraints identified.
文摘Solar energy is a very abundant renewable energy source during the day. The solar energy received in a given point of the Earth is function of the time, the season and the latitude of the point. It has been proven that the solar energy received in one day by our planet is thirty times higher than the annual global energy consumption. Africa is one of the sunniest continents of the world. Nowadays, solar energy is attracting particular attention in the implementation of the energy policies. This renewable source is a key solution to world energy problems, especially in the context of global warming. Niger is identified as among the sunniest zones of the World. Knowledge of solar potential is one of the crucial parameters to master for energy applications. In this study, continuous measurements (at intervals of 5 minutes over 24 hours) of solar radiation have been carried out on the site of the National Center of Solar Energy of Niamey. These measurements were taken using the pyranometers, allowed us to collect the values of the daily global sunshine on a horizontal plane and on an inclined plane of the years 2015 and 2016. The treatment and the exploitation of these data allowed us to determine the daily and monthly duration of sunshine, then the impact of the clouds and dust on the solar radiation, to evaluate the solar potential of the site and determine the variations of this solar potential as a function of time. The results showed that the solar potential was very favorable for many solar applications.
