Identification results of water quality model parameter directly affect the accuracy of water quality numerical simulation. To overcome the difficulty of parameter identification caused by the measurement’s uncertain...Identification results of water quality model parameter directly affect the accuracy of water quality numerical simulation. To overcome the difficulty of parameter identification caused by the measurement’s uncertainty, a new method which is the coupling of Finite Difference Method and Markov Chain Monte Carlo is developed to identify the parameters of water quality model in this paper. Taking a certain long distance open channel as an example, the effects to the results of parameters identification with different noise are discussed under steady and un-steady non-uniform flow scenarios. And also this proposed method is compared with finite difference method and Nelder Mead Simplex. The results show that it can give better results by the new method. It has good noise resistance and provides a new way to identify water quality model parameters.展开更多
Nha Trang Bay is famous not only because of its beauty, but also of the biodiversity values, especially coral reefs. Thus, the sea water quality monitoring systems are necessary for effective and available managements...Nha Trang Bay is famous not only because of its beauty, but also of the biodiversity values, especially coral reefs. Thus, the sea water quality monitoring systems are necessary for effective and available managements to protect the ecosystems and for sustainable development. There have been several monitoring systems here but they have been done separately and unconnectedly. This research was done to take an overview and access the status and changes of water quality from 2007-2014. The data obtained rainy seasons over the years showed a quite good environment here. The environment changes were also monitored and there were some changes between seasons and over years, decreasing, increasing, or unobvious trends. However, the difference was not so much; and there was not the sign of environmental degradation in the bay from 2007 to 2014. Besides, the stoichiometric nutrients limitations were initially assessed. Since Si ratios here were always higher compared to N and P, there was not increased potential for non-diatom algal blooms. Together with the recorded nutrients concentration data, it can be said that there was no evidence of eutrophication in the bay. Although there was partial contamination of some parameters at few moments, the sea water quality of Nha Trang bay was still in a good condition （according to Vietnamese and ASEAN criteria）.展开更多
It is attractive and encouraging to develop new fluorescent carbon dots(CDs)with excellent optical properties and promising applications prospects.Herein,highly-efficient green emissive CDs(m-CDs)with a high quantum y...It is attractive and encouraging to develop new fluorescent carbon dots(CDs)with excellent optical properties and promising applications prospects.Herein,highly-efficient green emissive CDs(m-CDs)with a high quantum yield(QY)of 71.7%in water are prepared through a facile solvothermal method.Interestingly,the m-CDs exhibit excellent fluorescence stability in the pH range of 1–9.However,the fluorescence intensity of the m-CDs is almost completely quenched as the pH is increased from 9 to 10.The mechanism of the unique pH-responsive behavior is discussed in detail and a plausible mechanism is proposed.Owing to the unique pH-responsive behavior,the m-CDs are used as a on-off fluorescent probe for water quality identification.By combining the reversible pH-ultrasensitive optical properties of the m-CDs in the pH range of 9–10 with the glucose oxidase-mimicking(GOx-mimicking)ability of Au nanoparticles(AuNPs),glucose can be quantitatively detected.Finally,two environment-friendly starch-based solid-state fluorescence materials(powder and film)are developed through green preparation routes.展开更多
It is very common to design water supply system to adjust runoff. Thus it will not meet the practical needs if only the hydrologic drought in natural basin is studied. In practice the natural water balance and water d...It is very common to design water supply system to adjust runoff. Thus it will not meet the practical needs if only the hydrologic drought in natural basin is studied. In practice the natural water balance and water deficits must be researched, i. e. . the adjusting effects of the water supply sys- tem such as a reservoir should be considered, and the drought event be distinguished according to the special system. The problem of drought identification under adjusted runoff was investigated in this study. By considering water transfer during different periods, a method to distinguish hydrologic drought for the water supply system was developed, and a standard drought severity index SWDSI was proposed. The method has been applied in Pan Jiakou water supply system in China. From 1953 to 1997,a total of 14 hydrologic droughts were identified in the water supply system, among which there were 3 severe droughts, 6 moderate droughts and 5 light droughts. The results are in good agreement with the historic drought records.展开更多
Relining is a trenchless technology of recoating the inside walls of damaged water pipes using composite materials. In the Safe Pipe project, co-financed by Regione Lombardia, alternative polymeric materials for relin...Relining is a trenchless technology of recoating the inside walls of damaged water pipes using composite materials. In the Safe Pipe project, co-financed by Regione Lombardia, alternative polymeric materials for relining the drinking water distribution system of the city of Milan have been developed. Relining polymers have been evaluated for their toxicity. The identification of product impurities was performed by HPLC/HRMS and GC/MS analysis and safety evaluation was conducted applying toxicity data, when available, or applying QSAR models. Results showed low level of toxic substances in polymerized resins and in water samples in a migration/leaching test performed in a field experiment.展开更多
Industrial effluents discharged into surface water body present a high percent of pollution in Ghanaian streams and rivers. The current study assessed the effects of industrial effluent on the quality of Onukpawahe st...Industrial effluents discharged into surface water body present a high percent of pollution in Ghanaian streams and rivers. The current study assessed the effects of industrial effluent on the quality of Onukpawahe stream which receives industrial effluents from the Tema Metropolis. Effluent samples were collected from six （6） selected industries and the water samples were collected from sixteen （16） different locations on the Onukpawahe stream. Various physico-chemical parameters such as BOD, TDS, Conductivity, COD, pH, TSS, Turbidity, Temperature, Colour, Sulphate, Phosphate, Ammonia and Nitrate were analysed during the current investigation. The average values of all the physico-chemical parameters （except pH and DO） were all above the EPA sector specific effluent guidelines. It was established in the study that the industries have polluted the stream and have grievously compromised the quality of the Onukpawahe stream. The surface water and industrial effluent must be monitored by the authorities in order to prevent further degradation of the river quality.展开更多
The Yongding New River is essential for the water supplies of Tianjin.To date,there is no comprehensive report that assesses the year-round water quality of the Yongding New River Main stream.Moreover,little attention...The Yongding New River is essential for the water supplies of Tianjin.To date,there is no comprehensive report that assesses the year-round water quality of the Yongding New River Main stream.Moreover,little attention has been given to determining a combined weight for improving the traditional comprehensive water quality identification index(ICWQII)by the game theory.Seven water quality parameters were investigated monthly along the main stream of the Yongding New River from May 2018 to April 2019.Organic contaminants and nitrogen pollution were mainly caused by point sources pollution,and the total phosphorus mainly by non-point source pollution.Dramatic spatio-temporal variations of water quality parameters were jointly caused by different pollutant sources and hydrometeorological factors.In terms of this study,an improved comprehensive water quality identification index(ICWQII)based on entropy weight or variation coefficient and traditional CWQII underestimated the water qualities,and an ICWQII based on the superstandard multiple method overvalued the assessments.By contrast,water qualities assessments done with an ICWQII based on the game theory matched perfectly with the practical situation.The ICWQII based on game theory proposed in this study takes into account not only the degree of disorder and variation of water quality data,but also the influence of standard-exceeded pollution indicators,whose results are relatively reasonable.All findings and the ICWQII based on game theory can provide scientific support for decisions related to the water environment management of the Yongding New River and other waters.展开更多
文摘Identification results of water quality model parameter directly affect the accuracy of water quality numerical simulation. To overcome the difficulty of parameter identification caused by the measurement’s uncertainty, a new method which is the coupling of Finite Difference Method and Markov Chain Monte Carlo is developed to identify the parameters of water quality model in this paper. Taking a certain long distance open channel as an example, the effects to the results of parameters identification with different noise are discussed under steady and un-steady non-uniform flow scenarios. And also this proposed method is compared with finite difference method and Nelder Mead Simplex. The results show that it can give better results by the new method. It has good noise resistance and provides a new way to identify water quality model parameters.
文摘Nha Trang Bay is famous not only because of its beauty, but also of the biodiversity values, especially coral reefs. Thus, the sea water quality monitoring systems are necessary for effective and available managements to protect the ecosystems and for sustainable development. There have been several monitoring systems here but they have been done separately and unconnectedly. This research was done to take an overview and access the status and changes of water quality from 2007-2014. The data obtained rainy seasons over the years showed a quite good environment here. The environment changes were also monitored and there were some changes between seasons and over years, decreasing, increasing, or unobvious trends. However, the difference was not so much; and there was not the sign of environmental degradation in the bay from 2007 to 2014. Besides, the stoichiometric nutrients limitations were initially assessed. Since Si ratios here were always higher compared to N and P, there was not increased potential for non-diatom algal blooms. Together with the recorded nutrients concentration data, it can be said that there was no evidence of eutrophication in the bay. Although there was partial contamination of some parameters at few moments, the sea water quality of Nha Trang bay was still in a good condition （according to Vietnamese and ASEAN criteria）.
基金supported by the National Natural Science Foundation of China(Nos.21375123,21675151,and 21721003)the Ministry of Science and Technology of China(No.2016YFA0203203).
文摘It is attractive and encouraging to develop new fluorescent carbon dots(CDs)with excellent optical properties and promising applications prospects.Herein,highly-efficient green emissive CDs(m-CDs)with a high quantum yield(QY)of 71.7%in water are prepared through a facile solvothermal method.Interestingly,the m-CDs exhibit excellent fluorescence stability in the pH range of 1–9.However,the fluorescence intensity of the m-CDs is almost completely quenched as the pH is increased from 9 to 10.The mechanism of the unique pH-responsive behavior is discussed in detail and a plausible mechanism is proposed.Owing to the unique pH-responsive behavior,the m-CDs are used as a on-off fluorescent probe for water quality identification.By combining the reversible pH-ultrasensitive optical properties of the m-CDs in the pH range of 9–10 with the glucose oxidase-mimicking(GOx-mimicking)ability of Au nanoparticles(AuNPs),glucose can be quantitatively detected.Finally,two environment-friendly starch-based solid-state fluorescence materials(powder and film)are developed through green preparation routes.
基金Supported by National Natural Science Foundation of China ( No. 50579049) and Doctoral Special Foundationof China (No. 20040056060).
文摘It is very common to design water supply system to adjust runoff. Thus it will not meet the practical needs if only the hydrologic drought in natural basin is studied. In practice the natural water balance and water deficits must be researched, i. e. . the adjusting effects of the water supply sys- tem such as a reservoir should be considered, and the drought event be distinguished according to the special system. The problem of drought identification under adjusted runoff was investigated in this study. By considering water transfer during different periods, a method to distinguish hydrologic drought for the water supply system was developed, and a standard drought severity index SWDSI was proposed. The method has been applied in Pan Jiakou water supply system in China. From 1953 to 1997,a total of 14 hydrologic droughts were identified in the water supply system, among which there were 3 severe droughts, 6 moderate droughts and 5 light droughts. The results are in good agreement with the historic drought records.
文摘Relining is a trenchless technology of recoating the inside walls of damaged water pipes using composite materials. In the Safe Pipe project, co-financed by Regione Lombardia, alternative polymeric materials for relining the drinking water distribution system of the city of Milan have been developed. Relining polymers have been evaluated for their toxicity. The identification of product impurities was performed by HPLC/HRMS and GC/MS analysis and safety evaluation was conducted applying toxicity data, when available, or applying QSAR models. Results showed low level of toxic substances in polymerized resins and in water samples in a migration/leaching test performed in a field experiment.
文摘Industrial effluents discharged into surface water body present a high percent of pollution in Ghanaian streams and rivers. The current study assessed the effects of industrial effluent on the quality of Onukpawahe stream which receives industrial effluents from the Tema Metropolis. Effluent samples were collected from six （6） selected industries and the water samples were collected from sixteen （16） different locations on the Onukpawahe stream. Various physico-chemical parameters such as BOD, TDS, Conductivity, COD, pH, TSS, Turbidity, Temperature, Colour, Sulphate, Phosphate, Ammonia and Nitrate were analysed during the current investigation. The average values of all the physico-chemical parameters （except pH and DO） were all above the EPA sector specific effluent guidelines. It was established in the study that the industries have polluted the stream and have grievously compromised the quality of the Onukpawahe stream. The surface water and industrial effluent must be monitored by the authorities in order to prevent further degradation of the river quality.
基金supported by the National Natural Science Foundation of China(No.41807386)Tianjin Financial Budget Project of 2018。
文摘The Yongding New River is essential for the water supplies of Tianjin.To date,there is no comprehensive report that assesses the year-round water quality of the Yongding New River Main stream.Moreover,little attention has been given to determining a combined weight for improving the traditional comprehensive water quality identification index(ICWQII)by the game theory.Seven water quality parameters were investigated monthly along the main stream of the Yongding New River from May 2018 to April 2019.Organic contaminants and nitrogen pollution were mainly caused by point sources pollution,and the total phosphorus mainly by non-point source pollution.Dramatic spatio-temporal variations of water quality parameters were jointly caused by different pollutant sources and hydrometeorological factors.In terms of this study,an improved comprehensive water quality identification index(ICWQII)based on entropy weight or variation coefficient and traditional CWQII underestimated the water qualities,and an ICWQII based on the superstandard multiple method overvalued the assessments.By contrast,water qualities assessments done with an ICWQII based on the game theory matched perfectly with the practical situation.The ICWQII based on game theory proposed in this study takes into account not only the degree of disorder and variation of water quality data,but also the influence of standard-exceeded pollution indicators,whose results are relatively reasonable.All findings and the ICWQII based on game theory can provide scientific support for decisions related to the water environment management of the Yongding New River and other waters.
