Five years ago,Chinese government vowed to bring its energy consumption down by 20%against unit gross domestic product(GDP) during 2006 - 2010,an ambitious but realistic target laid down in a clear-cut term in its 11t...Five years ago,Chinese government vowed to bring its energy consumption down by 20%against unit gross domestic product(GDP) during 2006 - 2010,an ambitious but realistic target laid down in a clear-cut term in its 11th Five-Year Plan for Economic and Social Development.It’s time to finish the goal, but how?展开更多
This paper investigates modified fixed-time synchronization(FxTS)of complex networks(CNs)with time-varying delays based on continuous and discontinuous controllers.First,for the sake of making the settling time(ST)of ...This paper investigates modified fixed-time synchronization(FxTS)of complex networks(CNs)with time-varying delays based on continuous and discontinuous controllers.First,for the sake of making the settling time(ST)of FxTS is independent of the initial values and parameters of the CNs,a modified fixed-time(FxT)stability theorem is proposed,where the ST is determined by an arbitrary positive number given in advance.Then,continuous controller and discontinuous controller are designed to realize the modified FxTS target of CNs.In addition,based on the designed controllers,CNs can achieve synchronization at any given time,or even earlier.And control strategies effectively solve the problem of ST related to the parameters of CNs.Finally,an appropriate simulation example is conducted to examine the effectiveness of the designed control strategies.展开更多
Inexpensive flocculant-modified iron tailings sand(ITS)were converted into effective flocculation materials for cyanobacteria blooms.After composite modification with polyaluminum chloride(PAC)and polyacrylamide(PAM),...Inexpensive flocculant-modified iron tailings sand(ITS)were converted into effective flocculation materials for cyanobacteria blooms.After composite modification with polyaluminum chloride(PAC)and polyacrylamide(PAM),the surface charge of ITS was altered from negative to positive,and surface adhesion was increased by~1.5 times.PAC/PAM-modified ITS(PP-ITS)had strong flocculating effects on cyanobacteria,facilitating their removal.When the dosage of PP-ITS was 150 mg/L and the ratio of flocculant to ITS was 1:20,the elimination rate of cyanobacteria was as high as 90%.The flocs formed were better than those with chitosan-modified clays(CS-CA)and PAC-modified ITS(PAC-ITS)in terms of settling velocity,size,and recovery ability.The positively charged groups in the flocculant,such as-NH_(2) and Al^(3+),are attracted to negatively charged ions on the surface of ITS,altering the surface charge.Additionally,hydrogen bonds could form between amide side groups,and surface adhesion was improved through molecular association.Coupled with the strong bridging and sweeping effects of the flocculant,the flocs generated by PP-ITS formed rapidly and were large and resilient.The use of PP-ITS could effectively treat cyanobacteria blooms as well as solve the problem of ore tailings disposal.These results are of practical importance for engineering strategies to control cyanobacteria blooms,though there are still some issues that need to be addressed,such as how cyanobacteria flocs are collected and utilized after settling.展开更多
Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic...Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic,cadmium,mercury,lead,and iron in the estuaries of three transboundary rivers(Comoé,Bia,and Tanoé)in West Africa.Thus,the analysis of metal-associated sedimentation particle samples collected in rainy,flood,and dry seasons was required.Sediment traps were used to calculate the metal fluxes associated with sedimentation particles towards the Atlantic Ocean.Finally,the carcinogenic and non-carcinogenic risks of ingestion and dermal contact associated with sedimentation particles were assessed.The results showed that the total concentrations of trace metals in particulate matter were higher than in the UCC(Upper Crust Continental),with the exception of lead.The highest fluxes of lead,mercury,iron and arsenic associated with sedimented particles were observed during flood periods in the estuary of the Comoé,Bia and Tanoérivers.Cadmium fluxes associated with sedimentation particles were highest in the rainy season in the Bia and Comoéestuaries and in the flood season in the Tanoéestuary.Pearson’s correlation analysis and the enrichment factor showed that the trace metals were derived from anthropogenic activities such as mining and farming.In addition,contamination indices showed that sediment particles in the estuaries of the three rivers were severely contaminated with mercury.However,the results of potential human health risks associated with trace metals show that there is no probability of exposure of the community to harmful and carcinogenic effects through ingestion and dermal absorption of sediment particles.It is essential to integrate the information from this study into policy-and decision-making processes for better management of transboundary river water resources in coastal countries,particularly the Côte d’Ivoire.展开更多
In ultra-deep and large well sections,high collapse stresses and diminished annular return velocity present significant challenges to wellbore cleaning.With increasing depth,rising temperature and pressure constrain t...In ultra-deep and large well sections,high collapse stresses and diminished annular return velocity present significant challenges to wellbore cleaning.With increasing depth,rising temperature and pressure constrain the regulation of displacement and drilling fluid rheology,impairing the fluid’s capacity to transport cuttings effectively.A precise understanding of cuttings settlement behavior and terminal velocity is therefore essential for optimizing their removal.This study accounts for variations in wellbore temperature and pressure,incorporates non-spherical cuttings and wellbore diameter parameters,and develops accordingly a simplified model to predict terminal settlement velocity.Thecuttings carrying ratio is introduced as a metric for evaluatingwellbore cleanliness.Findings reveal that temperature and pressure fluctuations can alter terminal velocity by up to 3.4%.Cuttings shape plays a crucial role,with block-shaped cuttings requiring higher annular return velocity than flake-shaped ones at the same carrying ratio.As wellbore size increases,the minimum required carrying flow rate rises nonlinearly,though the rate of increase gradually declines.For a Φ444.5mmwellbore,a carrying ratio of at least 0.6 is recommended.Terminal velocity decreases with increasing consistency coefficient,particularly in high-viscosity regimes.The proposed carrying ratio offers a more accurate and practical assessment of wellbore cleanliness.展开更多
By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneousl...By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations （500, 100 and 50 mg/L, respectively） coagulated by polyaluminum chloride（PAC1） at the up-flow rates of 1 and 2 mm/s, respectively.展开更多
Criterion of differential settlement in subgrade is useful for keeping road in a good serving condition. The theory of traditional materials strength and their technologic economy are applied to analyze the additional...Criterion of differential settlement in subgrade is useful for keeping road in a good serving condition. The theory of traditional materials strength and their technologic economy are applied to analyze the additional bend stress of the pavement structure, the equivalent beam of elastic foundation and influence on the pavement structure of an uneven settlement. The allowable settling ratio of pavement index （ △i ） is got and is used to appraise the uneven settlement standard value in subgrade. The allowable settling ratio of pavement index is applied in an certain widening expressway project and △i ≤0.36 % is attained by the analyzing, calculating and adding a certain safe coefficient. This value was put into practice and is effective during the past two years.展开更多
A method of measuring the vortex beam topological charge(TC)is proposed based on a device that can directly extract the plane wave form from the vortex beam in which the different propagation angles of the plane waves...A method of measuring the vortex beam topological charge(TC)is proposed based on a device that can directly extract the plane wave form from the vortex beam in which the different propagation angles of the plane waves are uniquely related to the different TCs.Then the TC can be obtained by simply comparing the energy values perceived by two fixed sensors in the detection location with the help of twin omnidirectional energy absorbers(OEAs).Because the settled detection relies only on the simple quantitative value at two fixed positions,neither pattern recognition nor field analysis procedure is applied,thus allowing faster measurement.Some features of the methodology are investigated,and the numerical simulations verify the feasibility and robustness of the system.展开更多
Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fu...Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fungi.They were also examined for atlatoxin endotoxin, and potential to stimulate production of human interleukin 1β (IL-1β) and to consume complement.The concentrations of total microorganisms were consistently greater than 10~7 CFU/g and ranged from 10~7 to 10~9 CFU/g.In general, the level of microbial contamination was greater in the hay dust samples than in the rice dust samples, with bacteria being the most numerous microorganisms observed followed by molds, thermophilic actinomycetes, and yeasts.The predominant fungi were species of Aspergillus, Cladosporium, Penicillium.Trichosporon, and Cryplococcus.No significant levels of aflatoxin were observed and the isolates of A.flavus examined lack significant aflatoxigenic potential.The levels of microorganisms in these samples, the types of organisms found, and the inflammatory mediators such as endotoxin suggest that workers exposed to these dusts may be at risk for respiratory illness. 1990 Academic Press.Inc.展开更多
The SWAT model was used to predict total phosphorus (TP) loadings for a 1555-ha karst watershed—Chapel Branch Creek (CBC)—which drains to a lake via a reservoir-like embayment (R-E). The model was first tested for m...The SWAT model was used to predict total phosphorus (TP) loadings for a 1555-ha karst watershed—Chapel Branch Creek (CBC)—which drains to a lake via a reservoir-like embayment (R-E). The model was first tested for monthly streamflow predictions from tributaries draining three potential source areas as well as the downstream R-E, followed by TP loadings using data collected March 2007-October 2009. Source areas included 1) a golf course that received applied wastewater, 2) urban areas, highway, and some agricultural lands, and 3) a cave spring draining a second golf course along with agricultural and forested areas, including a substantial contribution of subsurface water via karst connectivity. SWAT predictions of mean monthly TP loadings at the first two source outlets were deemed reasonable. However, the predictions at the cave spring outlet were somewhat poorer, likely due to diffuse variable groundwater flow from an unknown drainage area larger than the actual surface watershed, for which monthly subsurface flow was represented as a point source during simulations. Further testing of the SWAT model to predict monthly TP loadings at the R-E, modeled as a completely mixed system, resulted in their over-predictions most of the months, except when high lake water levels occurred. The mean monthly and annual flows were calibrated to acceptable limits with the exception of flow over-prediction when lake levels were low and surface water from tributaries disappeared into karst connections. The discrepancy in TP load predictions was attributed primarily to the use of limited monthly TP data collected during baseflow in the embayment. However, for the 22-month period, over-prediction of mean monthly TP load (34.6 kg/mo) by 13% compared to measured load (30.6 kg/mo) in the embayment was deemed acceptable. Simulated results showed a 42% reduction in TP load due to settling in the embayment.展开更多
Asthma and allergies are considered by many physicians as being triggered by different substances in the air that people breathe. The lung is the most common site of injury by airborne pollutants. Acute effects, howev...Asthma and allergies are considered by many physicians as being triggered by different substances in the air that people breathe. The lung is the most common site of injury by airborne pollutants. Acute effects, however, may also include non-respiratory signs and symptoms, which may depend upon toxicological characteristics of the substances and host-related factors. The studying of indoor air quality can provide a method for appropriate remedial action. Research suggests that SHD （Settled House Dust） may be a significant source for indoor exposure to different substances. This research study consisted of sampling dust from homes in different area codes. The dust samples were collected from August 2006 thru March 2007 and analyzed using GC/MS （Gas Chromatography/Mass Spectrometry）. The purpose of this research study will display how sampling household dust is a powerful tool for identifying chemicals that contribute to poor indoor air quality.展开更多
The new national technical standards innovation base has officially settled in Guangzhou.The inauguration ceremony and a themed seminar were celebrated on December11,2015.Addressing the meeting,SAC Vice-Administrator ...The new national technical standards innovation base has officially settled in Guangzhou.The inauguration ceremony and a themed seminar were celebrated on December11,2015.Addressing the meeting,SAC Vice-Administrator Yu Xinli said that,the innovation base as an attempt to promote the innovative development of standardization is of great significance to deepen the reform and create favorable environment for standardization development.展开更多
Indoor settled harmattan dusts at seven sampling stations from the University of Agriculture Makurdi were collected between November, 2014 to March, 2015 (five months) using the wipe sampling methodology. Gravimetric ...Indoor settled harmattan dusts at seven sampling stations from the University of Agriculture Makurdi were collected between November, 2014 to March, 2015 (five months) using the wipe sampling methodology. Gravimetric measurement of the dust samples from all the sample locations revealed that dust loading within the institution during the period of assessment ranges from 4.475 - 6.533 g/m2. Masses of indoor settled dust were expectedly higher along high traffic, untarred roads and construction sites as well as in older buildings than others during the period of this study. AAS analysis of the dust samples shows that heavy metal concentrations (mg/kg dry weight) throughout the sampling stations during the period of investigation range from 0.2372 - 0.7152 for Cu, 293.6 - 884.9 for Fe, 4.265 - 68.55 for Mn and 4.239 - 42.53 for Zn. The concentrations of all the metals investigated were found to be lower when compared with related values in literature and were within acceptable limits during the period of this study. Pearson correlation matrix also shows positive correlation between the possible metal pairs at 95% level of confidence, indicating a similar source which may be from anthropogenic activities within and outside the area.展开更多
In spring this year,the writershad an interview at JiangsuSuntory Ltd,a Sino-Japanesejoint venture modern foodstuffenterprise founded 11 yearsago with a joint investment ofUS＄25 million,producingmainly Prince Brand b...In spring this year,the writershad an interview at JiangsuSuntory Ltd,a Sino-Japanesejoint venture modern foodstuffenterprise founded 11 yearsago with a joint investment ofUS＄25 million,producingmainly Prince Brand beer andmalt as well as other serialproducts.展开更多
China,the big factory offering various commodities to companies and individuals all over the world,is attracting more and more merchants purchasing goods in various ways,through agents,on site,via modern communication...China,the big factory offering various commodities to companies and individuals all over the world,is attracting more and more merchants purchasing goods in various ways,through agents,on site,via modern communication,etc.One essential concern of these merchants is the quality of these commodities.How can the commodity quality be ensured?If there are展开更多
《大学英语》精读课本(李荫华主编)第四册第一单元的课文中,有这样一句话:By the time I arrived home,the boys had al-ready settled their accounts:$150 in labor costs,$40 for gaso-line,and a like amount for giftsboxes of can...《大学英语》精读课本(李荫华主编)第四册第一单元的课文中,有这样一句话:By the time I arrived home,the boys had al-ready settled their accounts:$150 in labor costs,$40 for gaso-line,and a like amount for giftsboxes of candy for saintly neighborswho had VoIunteered starion wagons and help in delivery and展开更多
文摘Five years ago,Chinese government vowed to bring its energy consumption down by 20%against unit gross domestic product(GDP) during 2006 - 2010,an ambitious but realistic target laid down in a clear-cut term in its 11th Five-Year Plan for Economic and Social Development.It’s time to finish the goal, but how?
基金Supported by the National Natural Science Foundation of China(62476082)。
文摘This paper investigates modified fixed-time synchronization(FxTS)of complex networks(CNs)with time-varying delays based on continuous and discontinuous controllers.First,for the sake of making the settling time(ST)of FxTS is independent of the initial values and parameters of the CNs,a modified fixed-time(FxT)stability theorem is proposed,where the ST is determined by an arbitrary positive number given in advance.Then,continuous controller and discontinuous controller are designed to realize the modified FxTS target of CNs.In addition,based on the designed controllers,CNs can achieve synchronization at any given time,or even earlier.And control strategies effectively solve the problem of ST related to the parameters of CNs.Finally,an appropriate simulation example is conducted to examine the effectiveness of the designed control strategies.
基金Supported by the National Key Research and Development Program of China(No.2022 YFC 3202700)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX 24_0904)。
文摘Inexpensive flocculant-modified iron tailings sand(ITS)were converted into effective flocculation materials for cyanobacteria blooms.After composite modification with polyaluminum chloride(PAC)and polyacrylamide(PAM),the surface charge of ITS was altered from negative to positive,and surface adhesion was increased by~1.5 times.PAC/PAM-modified ITS(PP-ITS)had strong flocculating effects on cyanobacteria,facilitating their removal.When the dosage of PP-ITS was 150 mg/L and the ratio of flocculant to ITS was 1:20,the elimination rate of cyanobacteria was as high as 90%.The flocs formed were better than those with chitosan-modified clays(CS-CA)and PAC-modified ITS(PAC-ITS)in terms of settling velocity,size,and recovery ability.The positively charged groups in the flocculant,such as-NH_(2) and Al^(3+),are attracted to negatively charged ions on the surface of ITS,altering the surface charge.Additionally,hydrogen bonds could form between amide side groups,and surface adhesion was improved through molecular association.Coupled with the strong bridging and sweeping effects of the flocculant,the flocs generated by PP-ITS formed rapidly and were large and resilient.The use of PP-ITS could effectively treat cyanobacteria blooms as well as solve the problem of ore tailings disposal.These results are of practical importance for engineering strategies to control cyanobacteria blooms,though there are still some issues that need to be addressed,such as how cyanobacteria flocs are collected and utilized after settling.
文摘Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic,cadmium,mercury,lead,and iron in the estuaries of three transboundary rivers(Comoé,Bia,and Tanoé)in West Africa.Thus,the analysis of metal-associated sedimentation particle samples collected in rainy,flood,and dry seasons was required.Sediment traps were used to calculate the metal fluxes associated with sedimentation particles towards the Atlantic Ocean.Finally,the carcinogenic and non-carcinogenic risks of ingestion and dermal contact associated with sedimentation particles were assessed.The results showed that the total concentrations of trace metals in particulate matter were higher than in the UCC(Upper Crust Continental),with the exception of lead.The highest fluxes of lead,mercury,iron and arsenic associated with sedimented particles were observed during flood periods in the estuary of the Comoé,Bia and Tanoérivers.Cadmium fluxes associated with sedimentation particles were highest in the rainy season in the Bia and Comoéestuaries and in the flood season in the Tanoéestuary.Pearson’s correlation analysis and the enrichment factor showed that the trace metals were derived from anthropogenic activities such as mining and farming.In addition,contamination indices showed that sediment particles in the estuaries of the three rivers were severely contaminated with mercury.However,the results of potential human health risks associated with trace metals show that there is no probability of exposure of the community to harmful and carcinogenic effects through ingestion and dermal absorption of sediment particles.It is essential to integrate the information from this study into policy-and decision-making processes for better management of transboundary river water resources in coastal countries,particularly the Côte d’Ivoire.
基金partly supported by the National Natural Science Foundation of China(52304045)the Open Fund(PLN2023-40)of the National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)the Open Fund(2024-KFKT-08)of China National Petroleum Corporation Science and Technology Research Institute.
文摘In ultra-deep and large well sections,high collapse stresses and diminished annular return velocity present significant challenges to wellbore cleaning.With increasing depth,rising temperature and pressure constrain the regulation of displacement and drilling fluid rheology,impairing the fluid’s capacity to transport cuttings effectively.A precise understanding of cuttings settlement behavior and terminal velocity is therefore essential for optimizing their removal.This study accounts for variations in wellbore temperature and pressure,incorporates non-spherical cuttings and wellbore diameter parameters,and develops accordingly a simplified model to predict terminal settlement velocity.Thecuttings carrying ratio is introduced as a metric for evaluatingwellbore cleanliness.Findings reveal that temperature and pressure fluctuations can alter terminal velocity by up to 3.4%.Cuttings shape plays a crucial role,with block-shaped cuttings requiring higher annular return velocity than flake-shaped ones at the same carrying ratio.As wellbore size increases,the minimum required carrying flow rate rises nonlinearly,though the rate of increase gradually declines.For a Φ444.5mmwellbore,a carrying ratio of at least 0.6 is recommended.Terminal velocity decreases with increasing consistency coefficient,particularly in high-viscosity regimes.The proposed carrying ratio offers a more accurate and practical assessment of wellbore cleanliness.
基金The Hi-Tech Research and Development Program (863) of China (No. 2002AA601290 2003AA601010-03) and the NationalNatural Science Foundation of China (No. 50178067)
文摘By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations （500, 100 and 50 mg/L, respectively） coagulated by polyaluminum chloride（PAC1） at the up-flow rates of 1 and 2 mm/s, respectively.
基金Sponsored by Project of Ning Xia Hui Autonormous Region Communications Department2005
文摘Criterion of differential settlement in subgrade is useful for keeping road in a good serving condition. The theory of traditional materials strength and their technologic economy are applied to analyze the additional bend stress of the pavement structure, the equivalent beam of elastic foundation and influence on the pavement structure of an uneven settlement. The allowable settling ratio of pavement index （ △i ） is got and is used to appraise the uneven settlement standard value in subgrade. The allowable settling ratio of pavement index is applied in an certain widening expressway project and △i ≤0.36 % is attained by the analyzing, calculating and adding a certain safe coefficient. This value was put into practice and is effective during the past two years.
基金supported by the National Natural Science Foundation of China(Grant Nos.61975015,61575022,and 61421001)the Beijing Natural Science Foundation,China(Grant No.L191004).
文摘A method of measuring the vortex beam topological charge(TC)is proposed based on a device that can directly extract the plane wave form from the vortex beam in which the different propagation angles of the plane waves are uniquely related to the different TCs.Then the TC can be obtained by simply comparing the energy values perceived by two fixed sensors in the detection location with the help of twin omnidirectional energy absorbers(OEAs).Because the settled detection relies only on the simple quantitative value at two fixed positions,neither pattern recognition nor field analysis procedure is applied,thus allowing faster measurement.Some features of the methodology are investigated,and the numerical simulations verify the feasibility and robustness of the system.
文摘Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fungi.They were also examined for atlatoxin endotoxin, and potential to stimulate production of human interleukin 1β (IL-1β) and to consume complement.The concentrations of total microorganisms were consistently greater than 10~7 CFU/g and ranged from 10~7 to 10~9 CFU/g.In general, the level of microbial contamination was greater in the hay dust samples than in the rice dust samples, with bacteria being the most numerous microorganisms observed followed by molds, thermophilic actinomycetes, and yeasts.The predominant fungi were species of Aspergillus, Cladosporium, Penicillium.Trichosporon, and Cryplococcus.No significant levels of aflatoxin were observed and the isolates of A.flavus examined lack significant aflatoxigenic potential.The levels of microorganisms in these samples, the types of organisms found, and the inflammatory mediators such as endotoxin suggest that workers exposed to these dusts may be at risk for respiratory illness. 1990 Academic Press.Inc.
文摘The SWAT model was used to predict total phosphorus (TP) loadings for a 1555-ha karst watershed—Chapel Branch Creek (CBC)—which drains to a lake via a reservoir-like embayment (R-E). The model was first tested for monthly streamflow predictions from tributaries draining three potential source areas as well as the downstream R-E, followed by TP loadings using data collected March 2007-October 2009. Source areas included 1) a golf course that received applied wastewater, 2) urban areas, highway, and some agricultural lands, and 3) a cave spring draining a second golf course along with agricultural and forested areas, including a substantial contribution of subsurface water via karst connectivity. SWAT predictions of mean monthly TP loadings at the first two source outlets were deemed reasonable. However, the predictions at the cave spring outlet were somewhat poorer, likely due to diffuse variable groundwater flow from an unknown drainage area larger than the actual surface watershed, for which monthly subsurface flow was represented as a point source during simulations. Further testing of the SWAT model to predict monthly TP loadings at the R-E, modeled as a completely mixed system, resulted in their over-predictions most of the months, except when high lake water levels occurred. The mean monthly and annual flows were calibrated to acceptable limits with the exception of flow over-prediction when lake levels were low and surface water from tributaries disappeared into karst connections. The discrepancy in TP load predictions was attributed primarily to the use of limited monthly TP data collected during baseflow in the embayment. However, for the 22-month period, over-prediction of mean monthly TP load (34.6 kg/mo) by 13% compared to measured load (30.6 kg/mo) in the embayment was deemed acceptable. Simulated results showed a 42% reduction in TP load due to settling in the embayment.
文摘Asthma and allergies are considered by many physicians as being triggered by different substances in the air that people breathe. The lung is the most common site of injury by airborne pollutants. Acute effects, however, may also include non-respiratory signs and symptoms, which may depend upon toxicological characteristics of the substances and host-related factors. The studying of indoor air quality can provide a method for appropriate remedial action. Research suggests that SHD （Settled House Dust） may be a significant source for indoor exposure to different substances. This research study consisted of sampling dust from homes in different area codes. The dust samples were collected from August 2006 thru March 2007 and analyzed using GC/MS （Gas Chromatography/Mass Spectrometry）. The purpose of this research study will display how sampling household dust is a powerful tool for identifying chemicals that contribute to poor indoor air quality.
文摘The new national technical standards innovation base has officially settled in Guangzhou.The inauguration ceremony and a themed seminar were celebrated on December11,2015.Addressing the meeting,SAC Vice-Administrator Yu Xinli said that,the innovation base as an attempt to promote the innovative development of standardization is of great significance to deepen the reform and create favorable environment for standardization development.
文摘Indoor settled harmattan dusts at seven sampling stations from the University of Agriculture Makurdi were collected between November, 2014 to March, 2015 (five months) using the wipe sampling methodology. Gravimetric measurement of the dust samples from all the sample locations revealed that dust loading within the institution during the period of assessment ranges from 4.475 - 6.533 g/m2. Masses of indoor settled dust were expectedly higher along high traffic, untarred roads and construction sites as well as in older buildings than others during the period of this study. AAS analysis of the dust samples shows that heavy metal concentrations (mg/kg dry weight) throughout the sampling stations during the period of investigation range from 0.2372 - 0.7152 for Cu, 293.6 - 884.9 for Fe, 4.265 - 68.55 for Mn and 4.239 - 42.53 for Zn. The concentrations of all the metals investigated were found to be lower when compared with related values in literature and were within acceptable limits during the period of this study. Pearson correlation matrix also shows positive correlation between the possible metal pairs at 95% level of confidence, indicating a similar source which may be from anthropogenic activities within and outside the area.
文摘In spring this year,the writershad an interview at JiangsuSuntory Ltd,a Sino-Japanesejoint venture modern foodstuffenterprise founded 11 yearsago with a joint investment ofUS＄25 million,producingmainly Prince Brand beer andmalt as well as other serialproducts.
文摘China,the big factory offering various commodities to companies and individuals all over the world,is attracting more and more merchants purchasing goods in various ways,through agents,on site,via modern communication,etc.One essential concern of these merchants is the quality of these commodities.How can the commodity quality be ensured?If there are
文摘《大学英语》精读课本(李荫华主编)第四册第一单元的课文中,有这样一句话:By the time I arrived home,the boys had al-ready settled their accounts:$150 in labor costs,$40 for gaso-line,and a like amount for giftsboxes of candy for saintly neighborswho had VoIunteered starion wagons and help in delivery and
