Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic me...Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic method using High Resolution Mass Spectrometer (LC-HRMS) technique is proved to be suitable for simultaneous quantification of all ten identified impurities with required specificity, sensitivity, resolution, precision, accuracy, and other method characteristics as per ICH Guidelines. The acceptable limit of less than 2.9 μg/g was considered for evaluations, based on drug substance dosage and duration of treatment. The method stands most sensitive with a Limit of Detection of 0.35 μg/g, considering the challenge full acceptance criteria as per current regulatory standards.展开更多
Sediments play an important role in elemental cycling in the aquatic environment;it can be sensitive indicator for monitoring contaminants in aquatic environments. The heavy metal prominence, the amount and different ...Sediments play an important role in elemental cycling in the aquatic environment;it can be sensitive indicator for monitoring contaminants in aquatic environments. The heavy metal prominence, the amount and different forms of phosphorous present in the surface sediments of Kavvayi Wetland, which is in the south west coast of India was studied and reported in this paper. A total number of 10 surface sediment samples were taken from various regions of Kavvayi Lake and were subjected to heavy metal analysis and also phosphorous fractionation. Phosphorous forms in the sediment samples were determined by the modified sequential extraction procedure and among the inorganic phosphorous pool;Fe and Al bound phosphorous constituted the major portion while the Ca-bound phosphorous constituted the minor part only. Higher concentration of organic phosphorous was also detected in all the samples. The sediment samples were analyzed for heavy metals such as Fe, Mn, Cu, Pb, Cd, Ni, and Zn and the results showed comparatively higher concentration than the background values. The degree of contamination for each station was determined. Sediment pollution load index (PLI) values of the studied area ranged from 0.39 to 2.55 which indicated that the wetland sediments were polluted. Multivariate statistical techniques were applied to evaluate and characterize the analytical data. Spatial distribution maps of phosphorous fractions and heavy metals would help to identify the pollution sources and vulnerable sites.展开更多
Groundwater is an essential and vital component of our life support system. The deterioration in the groundwater quality due to geogenic and anthropogenic activities has drawn great attention as it is the major altern...Groundwater is an essential and vital component of our life support system. The deterioration in the groundwater quality due to geogenic and anthropogenic activities has drawn great attention as it is the major alternate source of domestic and drinking water supply. Groundwater and surface water samples collected from various locations in Guruvayur were analysed for selected physico-chemical and bacteriological parameters by adopting APHA standard methods. The results of the analysis indicated the chemical and bacteriological contamination due to the disposal of solid, organic and septic wastes in the surface water samples of Chakkamkandam, Palayur and Edappally which are the various locations in Gurauvayur. Also the groundwater samples of Guruvayur were contaminated. The study revealed that, the water samples examined were found to be above the permissible limits of Bureau of Indian Standards (BIS). The sewage inlets that open directly to the water body are the major source of pollutants. The monitoring of various water bodies indicates the importance of taking appropriate measures to treat the water resources before either discharged to wetlands or consumed by human beings. It is also recommended to continue the monitoring periodically to assess the pollution status of the area.展开更多
PM2.5 aerosols were sampled in urban Chengdu from April 2009 to January 2010, and their chemical compositions were characterized in detail for elements, water soluble inorganic ions, and carbonaceous matter. The annua...PM2.5 aerosols were sampled in urban Chengdu from April 2009 to January 2010, and their chemical compositions were characterized in detail for elements, water soluble inorganic ions, and carbonaceous matter. The annual average of PM2.5 was 165 μg m-3 , which is generally higher than measurements in other Chinese cities, suggesting serious particulate pollution issues in the city. Water soluble ions contributed 43.5% to the annual total PM2.5 mass, carbonaceous aerosols including elemental carbon and organic carbon contributed 32.0%, and trace elements contributed 13.8%. Distinct daily and seasonal variations were observed in the mass concentrations of PM2.5 and its components, reflecting the seasonal variations of different anthropogenic and natural sources. Weakly acidic to neutral particles were found for PM2.5 . Major sources of PM2.5 identified from source apportionment analysis included coal combustion, traffic exhaust, biomass burning, soil dust, and construction dust emissions. The low nitrate: sulfate ratio suggested that stationary emissions were more important than vehicle emissions. The reconstructed masses of ammonium sulfate, ammonium nitrate, particulate carbonaceous matter, and fine soil accounted for 79% of the total measured PM2.5 mass; they also accounted for 92% of the total measured particle scattering.展开更多
This study was conducted to measure the impact of a municipal solid waste landfill on groundwater quality around Njelianparamba, a solid waste dumping site in Kozhikode district, Kerala state, India. One of the major ...This study was conducted to measure the impact of a municipal solid waste landfill on groundwater quality around Njelianparamba, a solid waste dumping site in Kozhikode district, Kerala state, India. One of the major problems associated with dumping of municipal solid waste landfill is the release of leachate and its impact on surrounding groundwater. In this study, physico-chemical and bacteriological parameters of groundwater samples collected from the region surrounding the leachate area during the pre- and post-monsoon seasons were analysed. The majority of the groundwater samples contained contaminants at a level beyond the permissible limit set by the Bureau of Indian Standards for drinking water quality. The Geographic Information System software of the Environmental Systems Research Institute, (USA) ArcMap 10.1 was used to prepare spatial distribution maps of different parameters and Leachate Pollution Index and Water Quality Index in the study area were applied to assess the overall quality of groundwater. Characterisation of leachate and groundwater samples revealed that, water in the domestic wells has been deteriorated in response to the percolation of leachate. Additionally spatial and correlation analysis revealed that contamination was present maximum within 300 m radius around the landfill site.展开更多
Traffic-related pollutants adversely affect air quality, especially in regions near major roadways. The vehicleinduced turbulence(VIT) is a significant factor that controls the initial dilution, dispersion, and ultima...Traffic-related pollutants adversely affect air quality, especially in regions near major roadways. The vehicleinduced turbulence(VIT) is a significant factor that controls the initial dilution, dispersion, and ultimately the chemical and physical fate of pollutants by altering the conditions in the microenvironment. This study used a computational fluid dynamics(CFD) software FLUENT to model the vehicle-induced turbulence(VIT) generated on roadways, with a focus on impact of vehicle-vehicle interactions, traffic density and vehicle composition on turbulent kinetic energy(TKE). We show, for the first time, that the overall TKE from multiple vehicles traveling in series can be estimated by superimposing the TKE of each vehicle, without considering the distance between them while the distance is greater than one vehicle length. This finding is particularly significant since it enables a new approach to VIT simulations where the overall TKE is calculated as a function of number of vehicles. We found that the interactions between vehicles traveling next to each other in adjacent lanes are insignificant,regardless the directions of the traffic flow. Consequently, simulations of different traffic scenarios can be substantially simplified by treating two-way traffic as one-way traffic, with less than 5% difference in the overall volume-averaged TKE. We also developed equations that allow the estimation of the overall volume-averaged TKE as a function of the number and the type of vehicles.展开更多
To investigate aerosol optical properties in the Beijing metropolitan area,aerosol absorption coefficient(Ab) ,scattering coefficient(Sc) ,and fine particulate matter(PM2.5) were measured in the Beijing urban area fro...To investigate aerosol optical properties in the Beijing metropolitan area,aerosol absorption coefficient(Ab) ,scattering coefficient(Sc) ,and fine particulate matter(PM2.5) were measured in the Beijing urban area from 20 May to 30 August 2009.The average Ab,Sc,single scattering albedo(SSA) ,and PM2.5 concentration were 58.0±39.5 M m-1,343.5±353.7 M m-1,0.80±0.10 and 63.6±50.0-g m-3,respectively,during the observation period.Ab,Sc,and SSA all showed single peak diurnal variations,with their maximum values being measured at 0500,1000,and 1300 local time,respectively.Ab and Sc had a strong positive correlation with PM2.5,and Ab,Sc,and PM2.5 all had positive correlations with relative humidity and negative correlations with wind speed.展开更多
Contamination of drinking water due to fluoride is a severe health hazard problem. Excess of fluoride (>1.5 mg/l) in drinking water is harmful to human health. Various treatment technologies for removing fluoride f...Contamination of drinking water due to fluoride is a severe health hazard problem. Excess of fluoride (>1.5 mg/l) in drinking water is harmful to human health. Various treatment technologies for removing fluoride from groundwater have been investigated. The present study showed that Vetiveria zizanioides, a herbal plant of Kerala—commonly known as Vetiver is an effective adsorbent for the removal of fluoride from aqueous solution. Phosphoric acid activated Vetiver root showed good adsorption capacity than the fresh powdered Vetiver root. Batch sorptive defluoridation was conducted under variable experimental conditions such as pH, agitation time, dose of adsorbent and particle size. Maximum defluoridation was achieved at pH 6;there is a greater possibility of columbic interaction between fluoride ion and adsorbent surface at this pH. The percentage of fluoride removal in- creases with adsorbent dose and time at a given initial solute concentration. The surface and sorption characteristics were analyzed using SEM techniques. Freundlich as well as Langmuir isotherm were plotted and kinetic constants were determined.展开更多
Using the observed data from 184 stations over the Yunnan-Guizhou Plateau (YGP) from 1961 to 2005,the long-term trends in sunshine duration,cloud amount,dry visibility (Vd),dry extinction,and water vapor over the YGP ...Using the observed data from 184 stations over the Yunnan-Guizhou Plateau (YGP) from 1961 to 2005,the long-term trends in sunshine duration,cloud amount,dry visibility (Vd),dry extinction,and water vapor over the YGP are analyzed.The results show that 85% of the stations recorded shortening annual sunshine duration,with the decrease rates between -12.2 and -173.7 h/10yr.Results of Mann-Kendall tests indicate that,among the stations with decreasing sunshine duration,63.7% of them experienced an abrupt change that started in the 1970s and peaked in the 1980s.This decreasing trend has reversed in the early years of the 21st century.The cloud cover and water vapor content in the mid and lower levels over the YGP had no obvious changes during the study period.The annual averages of Vd declined from 34 km in the 1960s to 27 km at present.The annual mean dry extinction coefficient trended upward,from 0.176 to 0.190,on the YGP from 1980 to 2005.Analyses of cloud cover,water vapor,atmos-pheric visibility,and dry extinction coefficient revealed that emitted tropospheric aerosols (including air pollutants) resulting from increased energy consumption over the YGP could be a major factor influencing the reductions of sunshine duration and atmospheric visibility.展开更多
Increasing use on mountain summits has both social and ecological implications.High numbers of visitors climbing mountain summits can be a safety issue,particularly in areas where terrain or elevation leads to queuein...Increasing use on mountain summits has both social and ecological implications.High numbers of visitors climbing mountain summits can be a safety issue,particularly in areas where terrain or elevation leads to queueing that may cause time delays.Estimating visitor use levels at site specific locations en route to summits is needed to understand the potential benefits and impacts of visitor use in these locations.However,it can be difficult to obtain reliable and robust data to estimate use and develop statistical relationships because of the remote and harsh climates on mountain summits,as well as the financial and personnel requirements involved to collect the data in remote locations.In 2015,data were collected on the higher stretches of the Keyhole Route on Longs Peak in Rocky Mountain National Park,USA(RMNP)to better understand use levels near the summit and to explore potential statistical relationships to trailhead use data that are relatively easy to collect.Strong statistical relationships from robust regression analyses were found between trailhead use counts and daily and hourly use totals on the"Homestretch"which is a final section of the Keyhole Route.Additionally,a strong statistical relationship was found between total daily use and maximum hourly use on the Homestretch.The results suggest that trailhead counts are an accurate and reliable means from which to estimate use levels on upper portions of the Keyhole route.Moreover,this research demonstrates the usefulness of an approach using proxy variables to estimate visitor use along remote peaks where data collection can be difficult.These types of data can elucidate various options and decisions for park management teams who are charged with deciding if and how to manage high use areas.展开更多
Availability of clean water and adequate sanitation facilities are of prime importance for limiting diarrheal diseases. We examined the spatial information on the groundwater quality and sanitation facilities of a vil...Availability of clean water and adequate sanitation facilities are of prime importance for limiting diarrheal diseases. We examined the spatial information on the groundwater quality and sanitation facilities of a village in southern India using Geographic Information System (GIS) tools. Place of residence, position of wells and latrines were mapped and well water samples were tested for microbial contamination (Total Coliform Counts (TCC), Fecal Coliform Counts (FCC) and Fecal Streptococcal Counts (FSC)). A well structured questionnaire was administered to 50 residents of the selected areas to elicit information on water collection, handling and storage. The location and distances of wells from latrines were determined using the Global Positioning System (GPS) device and a tape rule respectively. Data on 170 cases of various water-borne diseases were collected from primary health centers in the study area. Groundwater in the village was found to be microbiologically unfit for consumption. Analysis using direct observations supplemented by GIS maps revealed poor planning, design of the wells and improper siting of wells from latrines which were found to be the possible reasons of groundwater contamination. There was a significant difference in TCC between covered and uncovered wells (p < 0.01) but no significant differences were observed in the FCC, FSC and well covering. The mean distance (6.44 ± 2.37 m) of wells from the latrines in the study area was below the limit (15.24 m or 50 ft) set by United State Environmental Protection Agency (USEPA). TCC and FCC increased with a decrease in distance between the wells and latrines with a significance (p < 0.01). A moderate negative correlation (r = -0.593, r = -0.470) was ensued between the distance from latrine and coliform count. This study accentuates the need to set standards for the siting of wells from latrines and need for treatment.展开更多
In reactor physics tests, it is important to monitor sub-criticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear r...In reactor physics tests, it is important to monitor sub-criticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear reactor. This technique is successfully applied at sufficiently high power level or to a core without an external neutron source where the neutron source term in point reactor kinetics equations may be neglected. For operation at low power levels or in the sub-critical domain, the increase in the fluctuation of the neutron signal may cause difficulties in the evaluation of reactivity and the effect of direct emission from the external neutron source may not be neglected. Therefore, contribution of the neutron source must be taken into account and this implies knowledge of a quantity proportional to the source strength, which calls the source term and then it should be determined. The research work has been conducted to measure reactivity with source term using a dedicated reactivity measurement system by the Least Square Inverse Kinetics Method (LSIKM). Application to a simulator of HANARO research reactor, Korea Atomic Energy Research Institute (KAERI), with known source strength and reactivity worth has showed consistent and satisfactory agreement.展开更多
文摘Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic method using High Resolution Mass Spectrometer (LC-HRMS) technique is proved to be suitable for simultaneous quantification of all ten identified impurities with required specificity, sensitivity, resolution, precision, accuracy, and other method characteristics as per ICH Guidelines. The acceptable limit of less than 2.9 μg/g was considered for evaluations, based on drug substance dosage and duration of treatment. The method stands most sensitive with a Limit of Detection of 0.35 μg/g, considering the challenge full acceptance criteria as per current regulatory standards.
文摘Sediments play an important role in elemental cycling in the aquatic environment;it can be sensitive indicator for monitoring contaminants in aquatic environments. The heavy metal prominence, the amount and different forms of phosphorous present in the surface sediments of Kavvayi Wetland, which is in the south west coast of India was studied and reported in this paper. A total number of 10 surface sediment samples were taken from various regions of Kavvayi Lake and were subjected to heavy metal analysis and also phosphorous fractionation. Phosphorous forms in the sediment samples were determined by the modified sequential extraction procedure and among the inorganic phosphorous pool;Fe and Al bound phosphorous constituted the major portion while the Ca-bound phosphorous constituted the minor part only. Higher concentration of organic phosphorous was also detected in all the samples. The sediment samples were analyzed for heavy metals such as Fe, Mn, Cu, Pb, Cd, Ni, and Zn and the results showed comparatively higher concentration than the background values. The degree of contamination for each station was determined. Sediment pollution load index (PLI) values of the studied area ranged from 0.39 to 2.55 which indicated that the wetland sediments were polluted. Multivariate statistical techniques were applied to evaluate and characterize the analytical data. Spatial distribution maps of phosphorous fractions and heavy metals would help to identify the pollution sources and vulnerable sites.
文摘Groundwater is an essential and vital component of our life support system. The deterioration in the groundwater quality due to geogenic and anthropogenic activities has drawn great attention as it is the major alternate source of domestic and drinking water supply. Groundwater and surface water samples collected from various locations in Guruvayur were analysed for selected physico-chemical and bacteriological parameters by adopting APHA standard methods. The results of the analysis indicated the chemical and bacteriological contamination due to the disposal of solid, organic and septic wastes in the surface water samples of Chakkamkandam, Palayur and Edappally which are the various locations in Gurauvayur. Also the groundwater samples of Guruvayur were contaminated. The study revealed that, the water samples examined were found to be above the permissible limits of Bureau of Indian Standards (BIS). The sewage inlets that open directly to the water body are the major source of pollutants. The monitoring of various water bodies indicates the importance of taking appropriate measures to treat the water resources before either discharged to wetlands or consumed by human beings. It is also recommended to continue the monitoring periodically to assess the pollution status of the area.
基金supported by the Special Scientific Research Funds for Environment Protection Commonweal Section of China (Grant Nos. 201009001)the National Basic Research Program of China (Grant No. 2010CB428503)+4 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. IAP09320)the National Natural Science Foundation of China (Grant Nos. 41075096 and 40975076)the Research and Development Special Fund for Public Welfare Industry (Meteorology) of the China Meteorological Administration (Grant No. GYHY201006047)the Ministry of Science and Technology of China (Grant No. 2010DFA22770)the Innovation Method Fund of China (Grant No. 2008IM020500)
文摘PM2.5 aerosols were sampled in urban Chengdu from April 2009 to January 2010, and their chemical compositions were characterized in detail for elements, water soluble inorganic ions, and carbonaceous matter. The annual average of PM2.5 was 165 μg m-3 , which is generally higher than measurements in other Chinese cities, suggesting serious particulate pollution issues in the city. Water soluble ions contributed 43.5% to the annual total PM2.5 mass, carbonaceous aerosols including elemental carbon and organic carbon contributed 32.0%, and trace elements contributed 13.8%. Distinct daily and seasonal variations were observed in the mass concentrations of PM2.5 and its components, reflecting the seasonal variations of different anthropogenic and natural sources. Weakly acidic to neutral particles were found for PM2.5 . Major sources of PM2.5 identified from source apportionment analysis included coal combustion, traffic exhaust, biomass burning, soil dust, and construction dust emissions. The low nitrate: sulfate ratio suggested that stationary emissions were more important than vehicle emissions. The reconstructed masses of ammonium sulfate, ammonium nitrate, particulate carbonaceous matter, and fine soil accounted for 79% of the total measured PM2.5 mass; they also accounted for 92% of the total measured particle scattering.
文摘This study was conducted to measure the impact of a municipal solid waste landfill on groundwater quality around Njelianparamba, a solid waste dumping site in Kozhikode district, Kerala state, India. One of the major problems associated with dumping of municipal solid waste landfill is the release of leachate and its impact on surrounding groundwater. In this study, physico-chemical and bacteriological parameters of groundwater samples collected from the region surrounding the leachate area during the pre- and post-monsoon seasons were analysed. The majority of the groundwater samples contained contaminants at a level beyond the permissible limit set by the Bureau of Indian Standards for drinking water quality. The Geographic Information System software of the Environmental Systems Research Institute, (USA) ArcMap 10.1 was used to prepare spatial distribution maps of different parameters and Leachate Pollution Index and Water Quality Index in the study area were applied to assess the overall quality of groundwater. Characterisation of leachate and groundwater samples revealed that, water in the domestic wells has been deteriorated in response to the percolation of leachate. Additionally spatial and correlation analysis revealed that contamination was present maximum within 300 m radius around the landfill site.
基金financial support from Environment Canada and the Government of Ontario (72021622) for a scholarship to YK
文摘Traffic-related pollutants adversely affect air quality, especially in regions near major roadways. The vehicleinduced turbulence(VIT) is a significant factor that controls the initial dilution, dispersion, and ultimately the chemical and physical fate of pollutants by altering the conditions in the microenvironment. This study used a computational fluid dynamics(CFD) software FLUENT to model the vehicle-induced turbulence(VIT) generated on roadways, with a focus on impact of vehicle-vehicle interactions, traffic density and vehicle composition on turbulent kinetic energy(TKE). We show, for the first time, that the overall TKE from multiple vehicles traveling in series can be estimated by superimposing the TKE of each vehicle, without considering the distance between them while the distance is greater than one vehicle length. This finding is particularly significant since it enables a new approach to VIT simulations where the overall TKE is calculated as a function of number of vehicles. We found that the interactions between vehicles traveling next to each other in adjacent lanes are insignificant,regardless the directions of the traffic flow. Consequently, simulations of different traffic scenarios can be substantially simplified by treating two-way traffic as one-way traffic, with less than 5% difference in the overall volume-averaged TKE. We also developed equations that allow the estimation of the overall volume-averaged TKE as a function of the number and the type of vehicles.
基金supported by the Pilot Project of the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX2-YW-Q11-03)the Research and Development Special Fund for Public Welfare Industry(Meteorology) of the China Meteorological Administration(Grant No. GYHY201006047)+2 种基金the Special Scientific Research Funds for Environment Protection Commonweal Section(Grant No.200809143)the Innovation Method Fund of China(Grant No.2008IM020500)the Ministry of Science and Technology of China(Grant No. 2010DFA22770)
文摘To investigate aerosol optical properties in the Beijing metropolitan area,aerosol absorption coefficient(Ab) ,scattering coefficient(Sc) ,and fine particulate matter(PM2.5) were measured in the Beijing urban area from 20 May to 30 August 2009.The average Ab,Sc,single scattering albedo(SSA) ,and PM2.5 concentration were 58.0±39.5 M m-1,343.5±353.7 M m-1,0.80±0.10 and 63.6±50.0-g m-3,respectively,during the observation period.Ab,Sc,and SSA all showed single peak diurnal variations,with their maximum values being measured at 0500,1000,and 1300 local time,respectively.Ab and Sc had a strong positive correlation with PM2.5,and Ab,Sc,and PM2.5 all had positive correlations with relative humidity and negative correlations with wind speed.
文摘Contamination of drinking water due to fluoride is a severe health hazard problem. Excess of fluoride (>1.5 mg/l) in drinking water is harmful to human health. Various treatment technologies for removing fluoride from groundwater have been investigated. The present study showed that Vetiveria zizanioides, a herbal plant of Kerala—commonly known as Vetiver is an effective adsorbent for the removal of fluoride from aqueous solution. Phosphoric acid activated Vetiver root showed good adsorption capacity than the fresh powdered Vetiver root. Batch sorptive defluoridation was conducted under variable experimental conditions such as pH, agitation time, dose of adsorbent and particle size. Maximum defluoridation was achieved at pH 6;there is a greater possibility of columbic interaction between fluoride ion and adsorbent surface at this pH. The percentage of fluoride removal in- creases with adsorbent dose and time at a given initial solute concentration. The surface and sorption characteristics were analyzed using SEM techniques. Freundlich as well as Langmuir isotherm were plotted and kinetic constants were determined.
基金funded by the National Natural Science Foundation of China (NSFC) (Grant No. 40965009)the Guizhou Provincial Meteorological Bureau Key Laboratory Programme (No. KF200906)
文摘Using the observed data from 184 stations over the Yunnan-Guizhou Plateau (YGP) from 1961 to 2005,the long-term trends in sunshine duration,cloud amount,dry visibility (Vd),dry extinction,and water vapor over the YGP are analyzed.The results show that 85% of the stations recorded shortening annual sunshine duration,with the decrease rates between -12.2 and -173.7 h/10yr.Results of Mann-Kendall tests indicate that,among the stations with decreasing sunshine duration,63.7% of them experienced an abrupt change that started in the 1970s and peaked in the 1980s.This decreasing trend has reversed in the early years of the 21st century.The cloud cover and water vapor content in the mid and lower levels over the YGP had no obvious changes during the study period.The annual averages of Vd declined from 34 km in the 1960s to 27 km at present.The annual mean dry extinction coefficient trended upward,from 0.176 to 0.190,on the YGP from 1980 to 2005.Analyses of cloud cover,water vapor,atmos-pheric visibility,and dry extinction coefficient revealed that emitted tropospheric aerosols (including air pollutants) resulting from increased energy consumption over the YGP could be a major factor influencing the reductions of sunshine duration and atmospheric visibility.
基金supported by the Rocky Mountain National Park, cooperative agreement number P15AC00895 with Utah State Universitthe Utah State Agricultural Experiment Stationthe Institute for Outdoor Recreation and Tourism for funding support
文摘Increasing use on mountain summits has both social and ecological implications.High numbers of visitors climbing mountain summits can be a safety issue,particularly in areas where terrain or elevation leads to queueing that may cause time delays.Estimating visitor use levels at site specific locations en route to summits is needed to understand the potential benefits and impacts of visitor use in these locations.However,it can be difficult to obtain reliable and robust data to estimate use and develop statistical relationships because of the remote and harsh climates on mountain summits,as well as the financial and personnel requirements involved to collect the data in remote locations.In 2015,data were collected on the higher stretches of the Keyhole Route on Longs Peak in Rocky Mountain National Park,USA(RMNP)to better understand use levels near the summit and to explore potential statistical relationships to trailhead use data that are relatively easy to collect.Strong statistical relationships from robust regression analyses were found between trailhead use counts and daily and hourly use totals on the"Homestretch"which is a final section of the Keyhole Route.Additionally,a strong statistical relationship was found between total daily use and maximum hourly use on the Homestretch.The results suggest that trailhead counts are an accurate and reliable means from which to estimate use levels on upper portions of the Keyhole route.Moreover,this research demonstrates the usefulness of an approach using proxy variables to estimate visitor use along remote peaks where data collection can be difficult.These types of data can elucidate various options and decisions for park management teams who are charged with deciding if and how to manage high use areas.
文摘Availability of clean water and adequate sanitation facilities are of prime importance for limiting diarrheal diseases. We examined the spatial information on the groundwater quality and sanitation facilities of a village in southern India using Geographic Information System (GIS) tools. Place of residence, position of wells and latrines were mapped and well water samples were tested for microbial contamination (Total Coliform Counts (TCC), Fecal Coliform Counts (FCC) and Fecal Streptococcal Counts (FSC)). A well structured questionnaire was administered to 50 residents of the selected areas to elicit information on water collection, handling and storage. The location and distances of wells from latrines were determined using the Global Positioning System (GPS) device and a tape rule respectively. Data on 170 cases of various water-borne diseases were collected from primary health centers in the study area. Groundwater in the village was found to be microbiologically unfit for consumption. Analysis using direct observations supplemented by GIS maps revealed poor planning, design of the wells and improper siting of wells from latrines which were found to be the possible reasons of groundwater contamination. There was a significant difference in TCC between covered and uncovered wells (p < 0.01) but no significant differences were observed in the FCC, FSC and well covering. The mean distance (6.44 ± 2.37 m) of wells from the latrines in the study area was below the limit (15.24 m or 50 ft) set by United State Environmental Protection Agency (USEPA). TCC and FCC increased with a decrease in distance between the wells and latrines with a significance (p < 0.01). A moderate negative correlation (r = -0.593, r = -0.470) was ensued between the distance from latrine and coliform count. This study accentuates the need to set standards for the siting of wells from latrines and need for treatment.
文摘In reactor physics tests, it is important to monitor sub-criticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear reactor. This technique is successfully applied at sufficiently high power level or to a core without an external neutron source where the neutron source term in point reactor kinetics equations may be neglected. For operation at low power levels or in the sub-critical domain, the increase in the fluctuation of the neutron signal may cause difficulties in the evaluation of reactivity and the effect of direct emission from the external neutron source may not be neglected. Therefore, contribution of the neutron source must be taken into account and this implies knowledge of a quantity proportional to the source strength, which calls the source term and then it should be determined. The research work has been conducted to measure reactivity with source term using a dedicated reactivity measurement system by the Least Square Inverse Kinetics Method (LSIKM). Application to a simulator of HANARO research reactor, Korea Atomic Energy Research Institute (KAERI), with known source strength and reactivity worth has showed consistent and satisfactory agreement.