Planning for water quality management is important for facilitating sustainable socio-economic development;however, the planning is also complicated by a variety of uncertainties and nonlinearities. In this study, an ...Planning for water quality management is important for facilitating sustainable socio-economic development;however, the planning is also complicated by a variety of uncertainties and nonlinearities. In this study, an interval-parameter fuzzy robust nonlinear programming (IFRNP) model was developed for water quality management to deal with such difficulties. The developed model incorporated interval nonlinear programming (INP) and fuzzy robust programming (FRP) methods within a general optimization framework. The developed IFRNP model not only could explicitly deal with uncertainties represented as discrete interval numbers and fuzzy membership functions, but also was able to deal with nonlinearities in the objective function.展开更多
In 2023,pivotal advancements in artificial intelligence(AI)have significantly experienced.With that in mind,traditional methodologies,notably the p-y approach,have struggled to accurately model the complex,nonlinear s...In 2023,pivotal advancements in artificial intelligence(AI)have significantly experienced.With that in mind,traditional methodologies,notably the p-y approach,have struggled to accurately model the complex,nonlinear soil-structure interactions of laterally loaded large-diameter drilled shafts.This study undertakes a rigorous evaluation of machine learning(ML)and deep learning(DL)techniques,offering a comprehensive review of their application in addressing this geotechnical challenge.A thorough review and comparative analysis have been carried out to investigate various AI models such as artificial neural networks(ANNs),relevance vector machines(RVMs),and least squares support vector machines(LSSVMs).It was found that despite ML approaches outperforming classic methods in predicting the lateral behavior of piles,their‘black box'nature and reliance only on a data-driven approach made their results showcase statistical robustness rather than clear geotechnical insights,a fact underscored by the mathematical equations derived from these studies.Furthermore,the research identified a gap in the availability of drilled shaft datasets,limiting the extendibility of current findings to large-diameter piles.An extensive dataset,compiled from a series of lateral loading tests on free-head drilled shaft with varying properties and geometries,was introduced to bridge this gap.The paper concluded with a direction for future research,proposes the integration of physics-informed neural networks(PINNs),combining data-driven models with fundamental geotechnical principles to improve both the interpretability and predictive accuracy of AI applications in geotechnical engineering,marking a novel contribution to the field.展开更多
Wet air oxidation(WAO), a liquid phase reaction between organic materials in water and oxygen, is one of the most economical and technologically viable advanced oxidation processes for wastewater treatment, particular...Wet air oxidation(WAO), a liquid phase reaction between organic materials in water and oxygen, is one of the most economical and technologically viable advanced oxidation processes for wastewater treatment, particularly toxic and high organic content wastewater. WAO is the liquid phase oxidation of organics or oxidizable inorganic components at elevated temperatures(125–320 °C) and pressures(0.5–20 MPa) using gaseous oxygen(or air) as oxidant. In the past two decades, the WAO process was widely studied and applied in the treatment of dye wastewater. Compared to conventional WAO, catalytic WAO processes have higher efficiency and use moderate reaction conditions. The catalysts included homogenous and heterogeneous types. The key points that need to be solved are recycling of homogenous catalysts and better stability of heterogeneous catalysts. In the present review, the technological processes are first introduced, then some research history and hotspots of WAO research are presented, and finally, its application in the treatment of dye wastewater in the past two decades is summarized to reveal the impressive changes in modes, trends, and conditions used. The application includes model pollutant studies and wastewater tests.展开更多
The dynamics of Cd scavenging from solutions by Fe/Mn oxides in natural surface coatings (NSCs) was investigated under laboratory conditions. Selective extraction methods were employed to estimate the contributions ...The dynamics of Cd scavenging from solutions by Fe/Mn oxides in natural surface coatings (NSCs) was investigated under laboratory conditions. Selective extraction methods were employed to estimate the contributions of Fe/Mn oxides, where hydroxylamine hydrochloride (0.01 mol/L NH2OH-HCl + 0.01 mol/L HNO3), sodium dithionite (0.4 mol/L Na2S2O4) and nitric acid (10% HNO3) were used as extraction reagents. The Cd scavenging was accomplished with developing periods of the NSCs (totally 21 data sets). The resulting process dynamics fitted well to the Elovich equation, demonstrating that the amount of Cd scavenged was proportional to the increments of Fe/Mn oxides that were accumulated in the NSCs. The amount of Cd bound to Fe oxides (MCdFe) and Mn oxides (MCdMn) could be quantified by solving two equations based on the properties of two extraction reagents. The amount of Cd scavenged by Fe/Mn oxides could also be estimated using MCdFe and MCdMn divided by the total amounts of Fe and Mn oxides in the NSCs, respectively. The results indicated that the Cd scavenging by Fe/Mn oxides was dominated by Fe oxides, with less roles attributed to Mn oxides. The estimated levels of Cd scavenging through Fe and Mn oxides agreed well with those predicted through additive-adsorption and linear-regression models.展开更多
Clay minerals are widespread in natural systems and have been widely used for the removal of pollutants. In this study, natural expanded vermiculite was used in adsorption tests to remove ammonium nitrogen from landfi...Clay minerals are widespread in natural systems and have been widely used for the removal of pollutants. In this study, natural expanded vermiculite was used in adsorption tests to remove ammonium nitrogen from landfill leachate. The modification of vermiculite was carried out using NaOH and HCl, and for both modifications the best concentration was 0.1 mol/L. The results produced by XRD (X-ray diffraction) showed that Al replaced K after modification of the vermiculite using HCl and that Mg and Na replaced K after modification using NaOH. It was observed that the adsorption capacity increased as the percentage in mass of K diminished. The Langmuir is the isotherm that presents the best fit of the data, and the values of RL (the Langmuir coefficient) suggest that the adsorption is linear. The thermodynamic parameters indicate that the process is spontaneous and endothermic, that there is a high affinity between the adsorbate and the adsorbent, and that physical adsorption is prevalent.展开更多
Bench-scale treatments with three mixtures of Mg and P salts, including K3PO4+MgSO4, K2HPO4+MgSO4, and KH2PO4+MgSO4 as additives in a simulated food waste aerobic composting process, were conducted to test the magn...Bench-scale treatments with three mixtures of Mg and P salts, including K3PO4+MgSO4, K2HPO4+MgSO4, and KH2PO4+MgSO4 as additives in a simulated food waste aerobic composting process, were conducted to test the magnesium ammonium phosphate(MAP) formation, and the compost products were analyzed by X-ray diffraction(XRD), Scanning electron microscopy(SEM), and Energy dispersive X-ray spectroscopy(EDS) analyses. The comparison results between XRD, SEM, and EDS analyses of MAPs in the dried compost and synthesized MAPs confirm the formation of MAP crystals in the simulated food waste aerobic composting process. The analysis of the compost also indicates that the addition of all the three mixtures of Mg and P salts in the aerobic composting process can increase nitrogen conservation and decrease nitrogen loss because of the formation of MAPs. The mechanism of MAP formation was verified as the reaction of ammonium(NH4+) with magnesium(Mg^2+) and phosphate[HnPO4^(3-n) , n=0, 1, and 2).展开更多
Single particle characterization can provide information on the evolution of size distribution and chemical composition of pollution aerosol. The work described the use of Scanning Electron Microscopy (SEM) combined w...Single particle characterization can provide information on the evolution of size distribution and chemical composition of pollution aerosol. The work described the use of Scanning Electron Microscopy (SEM) combined with X-ray Dispersive Energy Spectrometry (EDS) to characterize inorganic atmospheric particles samples collected on PM10 filters from January 2013 to October 2013 from three zones within the city of Hermosillo, Sonora. Specimens were initially processed by separating the collected particles from the filters by means of submersing a 2 cm2 section of each filter into isopropilic alcohol within a test tube for 5 minutes. Then, an aliquot of the suspension was placed over a sample holder and into the SEM. The different elements found amongst individual particles were Al, Ba, Ca, Cl, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, S, Si, Ti and U. The predominant elements are Al (17.10 At%), Si (10.17 At%), Ba (5.90 At%), Fe (5.45 At%) and U (2.32 At%). The particles were classified into groups based on morphology and elemental composition: particles of aluminosilicate, salts of sodium chloride, sulfates, metal particles, barium and uranium. These particles morphology and chemical composition, illustrate an abundance of natural elements within the zone. However, some of the elements presented are directly related with human activities, and are of much interest from the public health and environmental perspectives.展开更多
Similarly to other Latin American countries, urban air quality is a major concern in Colombia. The purpose of the present study was to explore citizens’ perception on local air pollution, its causes and impacts. A qu...Similarly to other Latin American countries, urban air quality is a major concern in Colombia. The purpose of the present study was to explore citizens’ perception on local air pollution, its causes and impacts. A questionnaire was individually applied to a sample of 994 participants. Relationships between demographic features and the perception on air quality were analyzed using a logistic regression, its odds ratio (OR), and a Chi-square test. Eighty percent of the respondents perceive their local air quality as either bad or fair, 65% recognize particulate matter as the main local air pollutant, and 90% recognize negative impacts on people’s health as the main consequence of air pollution. In contrast to other studies where age and economic status are variables highly related with public perception on the level of atmospheric pollution, in this study only the size of the cities has a statistically significant relationship with the perception on local air quality regarding the level of pollution(OR ≥ 1, confidence intervals > 1 and p-values < 0.05). While area sources such as mining and infrastructure construction are identified as the main sources of pollutant emissions in small towns (less than 50,000 inhabitants), in big cities, road traffic is identified as the main source contributor to atmospheric pollution. Opposite to data from official reports, and regardless of the size of the city, households are perceived as the place with greatest contribution to personal air pollution exposure. Results show that citizens are aware of the state of air quality and its health impact is a major concern. Such findings suggest people’s opinions can be used as provisional indicators in cities without data, as well as to monitor the results of local air quality management. As a complementary process, or at the same level of importance given to technical-based policy, citizen participation can contribute to a collective construction of urban air pollution control strategies.展开更多
Breakwaters can be used as artificial headlands in beach nourishment to mitigate coastal erosion. Longfengtou Beach, located on the southwest coast of Haitan Bay facing the Taiwan Strait on the northeast, suffers seve...Breakwaters can be used as artificial headlands in beach nourishment to mitigate coastal erosion. Longfengtou Beach, located on the southwest coast of Haitan Bay facing the Taiwan Strait on the northeast, suffers severe erosion, where the monsoon causes significant season hydrodynamic variations. Headland breakwaters are intended to be employed to mitigate coastal erosion. A 2D sediment transport model is established using MIKE21 based on current-wave coupling and calibrated by measured data. Summer and winter wave conditions are chosen as characteristic weak and strong waves respectively. The numerical results of suspended sediment concentration and seasonal morphological evolution are compared under the conditions with and without the headland breakwaters. Sediment transport in summer can be regarded as mainly determined by current field, while in winter wave effect is strong enough to change current field. The northern breakwater, nearly perpendicular to the ebb current direction, obstructs the currents and decreases velocity of the ebb currents, and confines the water carrying sediments within the protection area during the flood period. The southern breakwater also breaks the waves in advance and significantly reduces the hydrodynamic effects during the flood period and maintains high suspended sediment concentration in the protection area. In general, two headland breakwaters decrease the erosion near the beach and enlarge the deposition area, which play a significant role in prevention of sediment loss in nearshore area and mitigate coastal erosion.展开更多
A precise prediction of maximum scour depth around bridge foundations under ice covered condition is crucial for their safe design because underestimation may result in bridge failure and over-estimation will lead to ...A precise prediction of maximum scour depth around bridge foundations under ice covered condition is crucial for their safe design because underestimation may result in bridge failure and over-estimation will lead to unnecessary construction costs. Compared to pier scour depth predictions within an open channel, few studies have attempted to predict the extent of pier scour depth under ice-covered condition. The present work examines scour under ice by using a series of clear-water flume experiments employing two adjacent circular bridge piers in a uniform bed were exposed to open channel and both rough and smooth ice covered channels. The measured scour depths were compared to three commonly used bridge scour equations including Gao’s simplified equation, the HEC-18/Jones equation, and the Froehlich Design Equation. The present study has several advantages as it adds to the understanding of the physics of bridge pier scour under ice cover flow condition, it checks the validity and reliability of commonly used bridge pier equations, and it reveals whether they are valid for the case of scour under ice-covered flow conditions. In addition, it explains how accurately an equation developed for scour under open channel flow can predict scour around bridge piers under ice-covered flow condition.展开更多
The increase in anthropogenic activities occur along the upstream of Citarum River Basin (CRB) in Bandung regency had a negative impact to the water quality caused by the presence of human activity, it will be able ...The increase in anthropogenic activities occur along the upstream of Citarum River Basin (CRB) in Bandung regency had a negative impact to the water quality caused by the presence of human activity, it will be able to be a disruption to the ecosystem aquatic. The purpose of this study was to determine the relationship of the physical and chemical parameters of water and sediment to the presence of macrozoobenthos populations. Based on the result of Pearson Correlation Analysis (PCA), the parameters of COD, TOC and silt composition were the highest correlation to the macrozoobenthos population density, the value were 0.966, 0.865 and 0.576. Although PCA analysis is used to determine the relationship between the parameters of water, sediment and sediment particle distribution, the result showed that the water parameters were the mayor component affected the density of macrozoobenthos. While based on the composition of sediment, it is found that substrate as silt, clay and gravel and phosphate parameter affected the density of macrozoobenthos. The measurement of water quality also were calculated by Biotic Monitoring Working Party-Average Score Per Taxon (BMWP-ASPT) index showed that the quality were polluted condition, although by Pollution Index (IP) method showed as a light polluted category.展开更多
Fecal indicator bacteria, such as total coliforms and E. coli, are a challenge to control in urban and rural stormwater runoff. To assess the challenges of improving bacterial water quality standards in surface waters...Fecal indicator bacteria, such as total coliforms and E. coli, are a challenge to control in urban and rural stormwater runoff. To assess the challenges of improving bacterial water quality standards in surface waters, microcosm experiments were conducted to assess how decay rates of total coliforms and E. coli are affected by sediments and associated organic matter. Samples were collected at a lake embayment to create laboratory microcosms consisting of different combinations of unsterilized and sterilized water and sediment. Calculated first-order decay rate constants ranged from 0.021 to 0.047 h-1 for total coliforms and 0.017 and 0.037 h-1 for E. coli, depending on how each microcosm was prepared. It is evident that sediment in contact with the water column decreases bacteria decay rate, showing that care should be taken when designing stormwater treatment measures. In addition, high organic carbon content in the sediment temporarily increased bacteria concentrations in the water column. The results demonstrate that stormwater treatment measures, such as extended detention basins and constructed wetlands, must hold water for several days to allow for reduction of bacterial concentrations to acceptable levels. In addition, to troubleshoot detention basins and constructed wetlands for causes of high effluent bacterial concentrations, analyses of sediment, organic carbon, and water column depth should be conducted.展开更多
Overpopulation globally is an addressed issue impacting human lives, marine lives, and the surrounding ecosystem;it is adding pressure on the available resources that should be optimized to suit the needs. Yet with im...Overpopulation globally is an addressed issue impacting human lives, marine lives, and the surrounding ecosystem;it is adding pressure on the available resources that should be optimized to suit the needs. Yet with improper management of resources and monitoring of daily activities, the environment will be further negatively impacted. With overpopulation higher urbanization rates are noticed with the demand of seeking better health facilities, better education, better jobs and better well-being;this progression is driving more demand into the infrastructure sector to be able to accommodate the growth rates. Hence, the need to having sustainable communities aiming at optimizing the resources used, working towards more feasible, environmentally friendly and cost-effective communities with a better occupant’s experience is in action. Sustainable development goals (SDG) are vital goals developed by the United Nations Development Program (UNDP) in 2015 to address and guide through 17 interconnected global goals serving the previously mentioned trend. Out of the 17 goals, Sustainable Cities and Communities (goal #11) and Good Health and Well-Being (goal #3) are the focus of this paper directed towards holding a comparative analysis between the community scale commonly known and mostly used rating system Leadership of Energy and Environmental Design (LEED-Cities and Communities) (USA) versus similar rating systems like Tarsheed-Communities (Egypt) and Estidama-Pearl (UAE) rating systems meeting sustainable development goal #11. Conjointly, another complimenting comparative review of the occupant’s health and wellbeing rating systems, such as Fitwel (USA) and Well (USA) are studied under sustainable development goal #3;however, they are focused on a building scale assessment. Living Community Challenge (LCC, USA) rating system linking community rating system with health & wellbeing credits was first issued in 2006, yet is it not cost effective neither easy to apply acting as a primary step while being affordable, accessible, and easy to implement. The objective of this paper is to highlight the pros and gaps under both categories of studies of community rating system and occupants’ health & wellbeing rating systems based on scientific content and commercial acceptance and do-ability. This comparison is done via comparing credits and sections within each rating system type;this will support in addressing the focal points needed for an integrated rating system between both categories that will serve in meeting SDG Sustainable Cities and Communities (goal #11) and Good Health and Well-Being (goal #3).展开更多
文摘Planning for water quality management is important for facilitating sustainable socio-economic development;however, the planning is also complicated by a variety of uncertainties and nonlinearities. In this study, an interval-parameter fuzzy robust nonlinear programming (IFRNP) model was developed for water quality management to deal with such difficulties. The developed model incorporated interval nonlinear programming (INP) and fuzzy robust programming (FRP) methods within a general optimization framework. The developed IFRNP model not only could explicitly deal with uncertainties represented as discrete interval numbers and fuzzy membership functions, but also was able to deal with nonlinearities in the objective function.
基金Project(202203021212308)supported by the Fundamental Research Program of Shanxi Province,ChinaProject(HZKY20220508)supported by the Ministry of Education’s“Chunhui Plan”Cooperative Scientific Research Project,China+5 种基金Project(KF-22-16)supported by the Open Fund from the Key Lab of Eco-restoration of Regional Contaminated Environment(Shenyang University)Ministry of Education,ChinaProject(20222020)supported by the Doctoral Foundation of Taiyuan University of Science and Technology,ChinaProject(2022L297)supported by the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province,ChinaProject supported by the Startup Funds of San Diego State University,USAProject(202304051001016)supported by the Special Fund for Science and Technology Innovation Teams of Shanxi Province,China。
基金supported by Prince Sultan University(Grant No.PSU-CE-TECH-135,2023).
文摘In 2023,pivotal advancements in artificial intelligence(AI)have significantly experienced.With that in mind,traditional methodologies,notably the p-y approach,have struggled to accurately model the complex,nonlinear soil-structure interactions of laterally loaded large-diameter drilled shafts.This study undertakes a rigorous evaluation of machine learning(ML)and deep learning(DL)techniques,offering a comprehensive review of their application in addressing this geotechnical challenge.A thorough review and comparative analysis have been carried out to investigate various AI models such as artificial neural networks(ANNs),relevance vector machines(RVMs),and least squares support vector machines(LSSVMs).It was found that despite ML approaches outperforming classic methods in predicting the lateral behavior of piles,their‘black box'nature and reliance only on a data-driven approach made their results showcase statistical robustness rather than clear geotechnical insights,a fact underscored by the mathematical equations derived from these studies.Furthermore,the research identified a gap in the availability of drilled shaft datasets,limiting the extendibility of current findings to large-diameter piles.An extensive dataset,compiled from a series of lateral loading tests on free-head drilled shaft with varying properties and geometries,was introduced to bridge this gap.The paper concluded with a direction for future research,proposes the integration of physics-informed neural networks(PINNs),combining data-driven models with fundamental geotechnical principles to improve both the interpretability and predictive accuracy of AI applications in geotechnical engineering,marking a novel contribution to the field.
基金supported by Technological Educational Institute of Kavala(President:A.Ch.Mitropoulos)
文摘Wet air oxidation(WAO), a liquid phase reaction between organic materials in water and oxygen, is one of the most economical and technologically viable advanced oxidation processes for wastewater treatment, particularly toxic and high organic content wastewater. WAO is the liquid phase oxidation of organics or oxidizable inorganic components at elevated temperatures(125–320 °C) and pressures(0.5–20 MPa) using gaseous oxygen(or air) as oxidant. In the past two decades, the WAO process was widely studied and applied in the treatment of dye wastewater. Compared to conventional WAO, catalytic WAO processes have higher efficiency and use moderate reaction conditions. The catalysts included homogenous and heterogeneous types. The key points that need to be solved are recycling of homogenous catalysts and better stability of heterogeneous catalysts. In the present review, the technological processes are first introduced, then some research history and hotspots of WAO research are presented, and finally, its application in the treatment of dye wastewater in the past two decades is summarized to reveal the impressive changes in modes, trends, and conditions used. The application includes model pollutant studies and wastewater tests.
基金The National Basic Research Program (973) of China (No. 2004CB3418501)
文摘The dynamics of Cd scavenging from solutions by Fe/Mn oxides in natural surface coatings (NSCs) was investigated under laboratory conditions. Selective extraction methods were employed to estimate the contributions of Fe/Mn oxides, where hydroxylamine hydrochloride (0.01 mol/L NH2OH-HCl + 0.01 mol/L HNO3), sodium dithionite (0.4 mol/L Na2S2O4) and nitric acid (10% HNO3) were used as extraction reagents. The Cd scavenging was accomplished with developing periods of the NSCs (totally 21 data sets). The resulting process dynamics fitted well to the Elovich equation, demonstrating that the amount of Cd scavenged was proportional to the increments of Fe/Mn oxides that were accumulated in the NSCs. The amount of Cd bound to Fe oxides (MCdFe) and Mn oxides (MCdMn) could be quantified by solving two equations based on the properties of two extraction reagents. The amount of Cd scavenged by Fe/Mn oxides could also be estimated using MCdFe and MCdMn divided by the total amounts of Fe and Mn oxides in the NSCs, respectively. The results indicated that the Cd scavenging by Fe/Mn oxides was dominated by Fe oxides, with less roles attributed to Mn oxides. The estimated levels of Cd scavenging through Fe and Mn oxides agreed well with those predicted through additive-adsorption and linear-regression models.
文摘Clay minerals are widespread in natural systems and have been widely used for the removal of pollutants. In this study, natural expanded vermiculite was used in adsorption tests to remove ammonium nitrogen from landfill leachate. The modification of vermiculite was carried out using NaOH and HCl, and for both modifications the best concentration was 0.1 mol/L. The results produced by XRD (X-ray diffraction) showed that Al replaced K after modification of the vermiculite using HCl and that Mg and Na replaced K after modification using NaOH. It was observed that the adsorption capacity increased as the percentage in mass of K diminished. The Langmuir is the isotherm that presents the best fit of the data, and the values of RL (the Langmuir coefficient) suggest that the adsorption is linear. The thermodynamic parameters indicate that the process is spontaneous and endothermic, that there is a high affinity between the adsorbate and the adsorbent, and that physical adsorption is prevalent.
基金Supported by the Scholarship from China Scholarship Council(No.22822053)
文摘Bench-scale treatments with three mixtures of Mg and P salts, including K3PO4+MgSO4, K2HPO4+MgSO4, and KH2PO4+MgSO4 as additives in a simulated food waste aerobic composting process, were conducted to test the magnesium ammonium phosphate(MAP) formation, and the compost products were analyzed by X-ray diffraction(XRD), Scanning electron microscopy(SEM), and Energy dispersive X-ray spectroscopy(EDS) analyses. The comparison results between XRD, SEM, and EDS analyses of MAPs in the dried compost and synthesized MAPs confirm the formation of MAP crystals in the simulated food waste aerobic composting process. The analysis of the compost also indicates that the addition of all the three mixtures of Mg and P salts in the aerobic composting process can increase nitrogen conservation and decrease nitrogen loss because of the formation of MAPs. The mechanism of MAP formation was verified as the reaction of ammonium(NH4+) with magnesium(Mg^2+) and phosphate[HnPO4^(3-n) , n=0, 1, and 2).
文摘Single particle characterization can provide information on the evolution of size distribution and chemical composition of pollution aerosol. The work described the use of Scanning Electron Microscopy (SEM) combined with X-ray Dispersive Energy Spectrometry (EDS) to characterize inorganic atmospheric particles samples collected on PM10 filters from January 2013 to October 2013 from three zones within the city of Hermosillo, Sonora. Specimens were initially processed by separating the collected particles from the filters by means of submersing a 2 cm2 section of each filter into isopropilic alcohol within a test tube for 5 minutes. Then, an aliquot of the suspension was placed over a sample holder and into the SEM. The different elements found amongst individual particles were Al, Ba, Ca, Cl, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, S, Si, Ti and U. The predominant elements are Al (17.10 At%), Si (10.17 At%), Ba (5.90 At%), Fe (5.45 At%) and U (2.32 At%). The particles were classified into groups based on morphology and elemental composition: particles of aluminosilicate, salts of sodium chloride, sulfates, metal particles, barium and uranium. These particles morphology and chemical composition, illustrate an abundance of natural elements within the zone. However, some of the elements presented are directly related with human activities, and are of much interest from the public health and environmental perspectives.
文摘Similarly to other Latin American countries, urban air quality is a major concern in Colombia. The purpose of the present study was to explore citizens’ perception on local air pollution, its causes and impacts. A questionnaire was individually applied to a sample of 994 participants. Relationships between demographic features and the perception on air quality were analyzed using a logistic regression, its odds ratio (OR), and a Chi-square test. Eighty percent of the respondents perceive their local air quality as either bad or fair, 65% recognize particulate matter as the main local air pollutant, and 90% recognize negative impacts on people’s health as the main consequence of air pollution. In contrast to other studies where age and economic status are variables highly related with public perception on the level of atmospheric pollution, in this study only the size of the cities has a statistically significant relationship with the perception on local air quality regarding the level of pollution(OR ≥ 1, confidence intervals > 1 and p-values < 0.05). While area sources such as mining and infrastructure construction are identified as the main sources of pollutant emissions in small towns (less than 50,000 inhabitants), in big cities, road traffic is identified as the main source contributor to atmospheric pollution. Opposite to data from official reports, and regardless of the size of the city, households are perceived as the place with greatest contribution to personal air pollution exposure. Results show that citizens are aware of the state of air quality and its health impact is a major concern. Such findings suggest people’s opinions can be used as provisional indicators in cities without data, as well as to monitor the results of local air quality management. As a complementary process, or at the same level of importance given to technical-based policy, citizen participation can contribute to a collective construction of urban air pollution control strategies.
基金project supported by the Third Institute of Oceanography,State Oceanic Administrationpartly supported by the National Natural Science Foundation of China(No.41776098)
文摘Breakwaters can be used as artificial headlands in beach nourishment to mitigate coastal erosion. Longfengtou Beach, located on the southwest coast of Haitan Bay facing the Taiwan Strait on the northeast, suffers severe erosion, where the monsoon causes significant season hydrodynamic variations. Headland breakwaters are intended to be employed to mitigate coastal erosion. A 2D sediment transport model is established using MIKE21 based on current-wave coupling and calibrated by measured data. Summer and winter wave conditions are chosen as characteristic weak and strong waves respectively. The numerical results of suspended sediment concentration and seasonal morphological evolution are compared under the conditions with and without the headland breakwaters. Sediment transport in summer can be regarded as mainly determined by current field, while in winter wave effect is strong enough to change current field. The northern breakwater, nearly perpendicular to the ebb current direction, obstructs the currents and decreases velocity of the ebb currents, and confines the water carrying sediments within the protection area during the flood period. The southern breakwater also breaks the waves in advance and significantly reduces the hydrodynamic effects during the flood period and maintains high suspended sediment concentration in the protection area. In general, two headland breakwaters decrease the erosion near the beach and enlarge the deposition area, which play a significant role in prevention of sediment loss in nearshore area and mitigate coastal erosion.
文摘A precise prediction of maximum scour depth around bridge foundations under ice covered condition is crucial for their safe design because underestimation may result in bridge failure and over-estimation will lead to unnecessary construction costs. Compared to pier scour depth predictions within an open channel, few studies have attempted to predict the extent of pier scour depth under ice-covered condition. The present work examines scour under ice by using a series of clear-water flume experiments employing two adjacent circular bridge piers in a uniform bed were exposed to open channel and both rough and smooth ice covered channels. The measured scour depths were compared to three commonly used bridge scour equations including Gao’s simplified equation, the HEC-18/Jones equation, and the Froehlich Design Equation. The present study has several advantages as it adds to the understanding of the physics of bridge pier scour under ice cover flow condition, it checks the validity and reliability of commonly used bridge pier equations, and it reveals whether they are valid for the case of scour under ice-covered flow conditions. In addition, it explains how accurately an equation developed for scour under open channel flow can predict scour around bridge piers under ice-covered flow condition.
文摘The increase in anthropogenic activities occur along the upstream of Citarum River Basin (CRB) in Bandung regency had a negative impact to the water quality caused by the presence of human activity, it will be able to be a disruption to the ecosystem aquatic. The purpose of this study was to determine the relationship of the physical and chemical parameters of water and sediment to the presence of macrozoobenthos populations. Based on the result of Pearson Correlation Analysis (PCA), the parameters of COD, TOC and silt composition were the highest correlation to the macrozoobenthos population density, the value were 0.966, 0.865 and 0.576. Although PCA analysis is used to determine the relationship between the parameters of water, sediment and sediment particle distribution, the result showed that the water parameters were the mayor component affected the density of macrozoobenthos. While based on the composition of sediment, it is found that substrate as silt, clay and gravel and phosphate parameter affected the density of macrozoobenthos. The measurement of water quality also were calculated by Biotic Monitoring Working Party-Average Score Per Taxon (BMWP-ASPT) index showed that the quality were polluted condition, although by Pollution Index (IP) method showed as a light polluted category.
文摘Fecal indicator bacteria, such as total coliforms and E. coli, are a challenge to control in urban and rural stormwater runoff. To assess the challenges of improving bacterial water quality standards in surface waters, microcosm experiments were conducted to assess how decay rates of total coliforms and E. coli are affected by sediments and associated organic matter. Samples were collected at a lake embayment to create laboratory microcosms consisting of different combinations of unsterilized and sterilized water and sediment. Calculated first-order decay rate constants ranged from 0.021 to 0.047 h-1 for total coliforms and 0.017 and 0.037 h-1 for E. coli, depending on how each microcosm was prepared. It is evident that sediment in contact with the water column decreases bacteria decay rate, showing that care should be taken when designing stormwater treatment measures. In addition, high organic carbon content in the sediment temporarily increased bacteria concentrations in the water column. The results demonstrate that stormwater treatment measures, such as extended detention basins and constructed wetlands, must hold water for several days to allow for reduction of bacterial concentrations to acceptable levels. In addition, to troubleshoot detention basins and constructed wetlands for causes of high effluent bacterial concentrations, analyses of sediment, organic carbon, and water column depth should be conducted.
文摘Overpopulation globally is an addressed issue impacting human lives, marine lives, and the surrounding ecosystem;it is adding pressure on the available resources that should be optimized to suit the needs. Yet with improper management of resources and monitoring of daily activities, the environment will be further negatively impacted. With overpopulation higher urbanization rates are noticed with the demand of seeking better health facilities, better education, better jobs and better well-being;this progression is driving more demand into the infrastructure sector to be able to accommodate the growth rates. Hence, the need to having sustainable communities aiming at optimizing the resources used, working towards more feasible, environmentally friendly and cost-effective communities with a better occupant’s experience is in action. Sustainable development goals (SDG) are vital goals developed by the United Nations Development Program (UNDP) in 2015 to address and guide through 17 interconnected global goals serving the previously mentioned trend. Out of the 17 goals, Sustainable Cities and Communities (goal #11) and Good Health and Well-Being (goal #3) are the focus of this paper directed towards holding a comparative analysis between the community scale commonly known and mostly used rating system Leadership of Energy and Environmental Design (LEED-Cities and Communities) (USA) versus similar rating systems like Tarsheed-Communities (Egypt) and Estidama-Pearl (UAE) rating systems meeting sustainable development goal #11. Conjointly, another complimenting comparative review of the occupant’s health and wellbeing rating systems, such as Fitwel (USA) and Well (USA) are studied under sustainable development goal #3;however, they are focused on a building scale assessment. Living Community Challenge (LCC, USA) rating system linking community rating system with health & wellbeing credits was first issued in 2006, yet is it not cost effective neither easy to apply acting as a primary step while being affordable, accessible, and easy to implement. The objective of this paper is to highlight the pros and gaps under both categories of studies of community rating system and occupants’ health & wellbeing rating systems based on scientific content and commercial acceptance and do-ability. This comparison is done via comparing credits and sections within each rating system type;this will support in addressing the focal points needed for an integrated rating system between both categories that will serve in meeting SDG Sustainable Cities and Communities (goal #11) and Good Health and Well-Being (goal #3).