Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, fiv...Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961– 1990) and future (2011–2100) under SRES B2 scenario. The results showed the mean annual rainstorm days over the basin by the near-term, mid-term and long-term would increase from 3.9 days to 4.7, 4.9 and 5.1 days, and the mean annual maximum 3-day precipitation from 122 mm to 143, 146 and 149 mm, respectively. The flood hazard of the basin would become more severe, especially in the middle and lower reaches. Flood hazard grade 5 by the nearterm, mid-term and long-term would extend from 10.99% to 25.46, 28.14 and 29.75%, respectively.展开更多
The rapid rise of modern industry is the source of unchecked effluents containing many pernicious heavy metals (e.g.,cadmium).To rehabilitate the ecology,food resources,and health of humans and animals,various convent...The rapid rise of modern industry is the source of unchecked effluents containing many pernicious heavy metals (e.g.,cadmium).To rehabilitate the ecology,food resources,and health of humans and animals,various conventional methodologies are being used in wastewater treatment facilities for the abatement of cadmium.Nonetheless,the development of advanced,economical,and efficient adsorbents is needed because of the many shortcomings of conventional methods (e.g.,high cost,intensive operation,and inefficiency).Recent advancements in materials science and chemistry have introduced the use of nanomaterials,which possess very high specific surface areas and multiple functionalities,for the removal of specific targets such as cadmium.This review explores the recent developments and trends in nanomaterial adsorption technology for the mitigation of cadmium.The paper further surveys the present obstacles and future opportunities for the advancement of nanomaterial-based technologies in the area of water treatment.展开更多
Advances in metal-organic frameworks （lVIOFs） resulted in significant contributions to diverse applications such as carbon capture, gas storage, heat transformation and separation along with emerging applications to...Advances in metal-organic frameworks （lVIOFs） resulted in significant contributions to diverse applications such as carbon capture, gas storage, heat transformation and separation along with emerging applications toward catalysis, medical imaging, drug deliver~ and sensing. The unique in situ and ex situ structural features of MOFs can be tailored by conceptual selection of the organic （e.g., ligand） and inorganic （e.g., metal） components. Here, we provide a comprehensive review on the synthesis and characterization of MOFs, particularly with respect to controlling their size and morphology. A better understanding of the specific size and morphological parameters of MOFs will help initiate a new era for their real-world applications. Most importantly, this assessment will help develop novel synthesis methods for MOFs and their hybrid/porous materials counterparts with considerably improved properties in targeted applications.展开更多
Despite the improvement in sensing technologies, detection of small and highly reactive molecules like formaldehyde remains a highly challenging area of research. Applications of nanomaterials/nanostructures and their...Despite the improvement in sensing technologies, detection of small and highly reactive molecules like formaldehyde remains a highly challenging area of research. Applications of nanomaterials/nanostructures and their composites have increased as effective sensing platforms (e.g., reaction time, sensitivity, and selectivity) for the detection of aqueous or gaseous formaldehyde based on diverse sensing principles. In this review, the basic aspects of important nanomaterial-based sensing systems (e.g., electrochemical, electrical, biological, and mass variation sensors) were evaluated in relation to performance, cost, and practicality of sensing gas phase formaldehyde. Accordingly, existing knowledge gaps in such applications were assessed in various respects along with suitable recommendations for building a new roadmap for the expansion of chemical sensing technology of gas phase formaldehyde.展开更多
Nitrous oxide （N2O） emission has been reported to be enhanced during denitrification when internally-stored compounds are used as carbon sources. However, negligible N2O emissions have been detected in the few studi...Nitrous oxide （N2O） emission has been reported to be enhanced during denitrification when internally-stored compounds are used as carbon sources. However, negligible N2O emissions have been detected in the few studies where polyhydroxyalkanoates （PHA） were specifically used. This study investigated and compared the potential enhancement of N2O production, based on utilization of an internally-stored polymer and external carbon （acetate） by a denitrifying phosphorus removal culture. Results indicated that at relatively low chemical oxygen demand-to-nitrogen （COD/N） ratios, more nitrite was reduced to N2O in the presence of an external carbon source as compared to an internal carbon source （PHA）. At relatively higher COD/N ratios, similar N2O reduction rates were obtained in all cases regardless of the type of carbon source available. N2O reduction rates were, however, generally higher in the presence of an internal carbon source. Results from the study imply that when the presence of an external carbon source is not sufficient to support denitrification, it is likely competitively utilized by different metabolic pathways of denitrifying polyphosphate accumulating organisms （DPAOs） and other ordinary denitfifiers. This study also reveals that the consumption of PHA is potentially the rate-limiting step for N2O reduction during denitrification.展开更多
基金supported by the National Technology R&D Program (Grant nos. 2006BAD20B05 and 2008BAK50B06)
文摘Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961– 1990) and future (2011–2100) under SRES B2 scenario. The results showed the mean annual rainstorm days over the basin by the near-term, mid-term and long-term would increase from 3.9 days to 4.7, 4.9 and 5.1 days, and the mean annual maximum 3-day precipitation from 122 mm to 143, 146 and 149 mm, respectively. The flood hazard of the basin would become more severe, especially in the middle and lower reaches. Flood hazard grade 5 by the nearterm, mid-term and long-term would extend from 10.99% to 25.46, 28.14 and 29.75%, respectively.
文摘The rapid rise of modern industry is the source of unchecked effluents containing many pernicious heavy metals (e.g.,cadmium).To rehabilitate the ecology,food resources,and health of humans and animals,various conventional methodologies are being used in wastewater treatment facilities for the abatement of cadmium.Nonetheless,the development of advanced,economical,and efficient adsorbents is needed because of the many shortcomings of conventional methods (e.g.,high cost,intensive operation,and inefficiency).Recent advancements in materials science and chemistry have introduced the use of nanomaterials,which possess very high specific surface areas and multiple functionalities,for the removal of specific targets such as cadmium.This review explores the recent developments and trends in nanomaterial adsorption technology for the mitigation of cadmium.The paper further surveys the present obstacles and future opportunities for the advancement of nanomaterial-based technologies in the area of water treatment.
文摘Advances in metal-organic frameworks （lVIOFs） resulted in significant contributions to diverse applications such as carbon capture, gas storage, heat transformation and separation along with emerging applications toward catalysis, medical imaging, drug deliver~ and sensing. The unique in situ and ex situ structural features of MOFs can be tailored by conceptual selection of the organic （e.g., ligand） and inorganic （e.g., metal） components. Here, we provide a comprehensive review on the synthesis and characterization of MOFs, particularly with respect to controlling their size and morphology. A better understanding of the specific size and morphological parameters of MOFs will help initiate a new era for their real-world applications. Most importantly, this assessment will help develop novel synthesis methods for MOFs and their hybrid/porous materials counterparts with considerably improved properties in targeted applications.
文摘Despite the improvement in sensing technologies, detection of small and highly reactive molecules like formaldehyde remains a highly challenging area of research. Applications of nanomaterials/nanostructures and their composites have increased as effective sensing platforms (e.g., reaction time, sensitivity, and selectivity) for the detection of aqueous or gaseous formaldehyde based on diverse sensing principles. In this review, the basic aspects of important nanomaterial-based sensing systems (e.g., electrochemical, electrical, biological, and mass variation sensors) were evaluated in relation to performance, cost, and practicality of sensing gas phase formaldehyde. Accordingly, existing knowledge gaps in such applications were assessed in various respects along with suitable recommendations for building a new roadmap for the expansion of chemical sensing technology of gas phase formaldehyde.
文摘Nitrous oxide （N2O） emission has been reported to be enhanced during denitrification when internally-stored compounds are used as carbon sources. However, negligible N2O emissions have been detected in the few studies where polyhydroxyalkanoates （PHA） were specifically used. This study investigated and compared the potential enhancement of N2O production, based on utilization of an internally-stored polymer and external carbon （acetate） by a denitrifying phosphorus removal culture. Results indicated that at relatively low chemical oxygen demand-to-nitrogen （COD/N） ratios, more nitrite was reduced to N2O in the presence of an external carbon source as compared to an internal carbon source （PHA）. At relatively higher COD/N ratios, similar N2O reduction rates were obtained in all cases regardless of the type of carbon source available. N2O reduction rates were, however, generally higher in the presence of an internal carbon source. Results from the study imply that when the presence of an external carbon source is not sufficient to support denitrification, it is likely competitively utilized by different metabolic pathways of denitrifying polyphosphate accumulating organisms （DPAOs） and other ordinary denitfifiers. This study also reveals that the consumption of PHA is potentially the rate-limiting step for N2O reduction during denitrification.
