Flash point is a primary property used to determine the fire and explosion hazards of a liquid. New group contribution-based models were presented for estimation of the flash point of alkanes by the use of multiple li...Flash point is a primary property used to determine the fire and explosion hazards of a liquid. New group contribution-based models were presented for estimation of the flash point of alkanes by the use of multiple linear regression(MLR)and artificial neural network(ANN). This simple linear model shows a low average relative deviation(AARD) of 2.8% for a data set including 50(40 for training set and 10 for validation set) flash points. Furthermore, the predictive ability of the model was evaluated using LOO cross validation. The results demonstrate ANN model is clearly superior both in fitness and in prediction performance.ANN model has only the average absolute deviation of 2.9 K and the average relative deviation of 0.72%.展开更多
Direct membrane filtration(DMF)is a popular option for raw sewage pre-concentration for the subsequent organic resource recovery.It undergoes rapid and severe fouling.To achieve a fundamental understanding of the cont...Direct membrane filtration(DMF)is a popular option for raw sewage pre-concentration for the subsequent organic resource recovery.It undergoes rapid and severe fouling.To achieve a fundamental understanding of the contributions of key foulants to DMF,principal component analysis(PCA)using Fourier transform infrared spectroscopy(FTIR)was applied to identify three stages of DMF.Variance partitioning analysis(VPA)and partial least squares(PLS)were used to quantitatively determine the contributions of key foulants.Humic acid(HA)achieved the highest intersection contribution(40.5%)to the total variance of the increase in resistance.Meanwhile,HA and protein(PN)explained 20.1%in the middle stage of DMF.The overall marginal effect of HA accounted for 42.5%of the variance,in conjunction with an overall individual effect of 11.0%(which was the highest in the initial stage:15.1%).The variable importance in projection(VIP)of impact on the resistance increase of DMF were 1.16(PN),0.99(HA),and 0.82(polysaccharides,PS).HA&PN with a VIP value approaching or larger than one significantly influenced the resistance increase in DMF.Meanwhile,the VIP of impact on blocking model alteration were 1.03(PS),1.01(PN),and 0.96(HA).HA,PS,and PN were regarded as vital factors in the fouling mode alteration.PS drives the fouling mode in the initial stage,whereas HA&PN and PN play dominant roles in the middle and final stages.Measures targeting HA and PN removal can be adapted for the efficient and cost-effective fouling control of raw sewage DMF.展开更多
From 1956 to 2016,Hai River Basin suffered the most severe surface water resource attenuation among the 10 first-class river basins in China.Based on the surface water circulation process,and evolving characteristics ...From 1956 to 2016,Hai River Basin suffered the most severe surface water resource attenuation among the 10 first-class river basins in China.Based on the surface water circulation process,and evolving characteristics of precipitation and underlying surface in Hai River Basin,this study attributed the causes of surface water resource attenuation to six primary impact factors,analyzed each factor's quantitative contribution,and revealed four patterns of surface water resource attenuation in Hai River Basin.The pattern of the dominant factor:comparing the 1980–2000 period with the 1956–1979period,the variation of precipitation is the dominant factor of which contribution is 7 billion m^(3),accounting for 59%of total11.7 billion m^(3);comparing the 2001–2016 period with the 1956–1979 period,the increasing of vegetation cover in mountainous area is the dominant factor of which contribution is 2.78 billion m3,accounting for 51%of total 4.9 billion m^(3).The pattern of spatial distributions:comparing the 2001–2016 period with the 1956–1979 period,mountainous areas were more affected by increasing vegetation cover which for example contributed 42%in Luan River Basin mountainous;the plains were more impacted by farmland ridge interception which for example contributed 51%in Beisi River Basin plains.The pattern of attenuation trend:comparing the 2001–2016 period with the 1980–2000 period,surface water resources in mountainous areas continued to decline,owing to the increasing water consumption of large-scale vegetation restoration,while the influence of the underlying surface changes on surface water resources in plains areas tended to remain stable.The pattern of reversible change:among factors led to surface water resource attenuation,the human activity,including vegetation cover increase,farmland ridge interception,and urbanization expansion,contributed 36%of the attenuation,which resulted in the variation of precipitation-runoff relation.This study improved the traditional attribution classification model of climate change and human activity and analyzed the causes and contributions of water resource attenuation in Hai River Basin based on the water circulation process,which can provide scientific support for the development of water resource management in the basin.展开更多
Polymethyl methacrylate（PMMA） plate luminescent solar concentrators with a bottom-mounted（BM-LSCs）photovoltaic（PV） cell are fabricated by using a mixture of Lumogen Red 305 and Yellow 083 fluorescent dyes and a ...Polymethyl methacrylate（PMMA） plate luminescent solar concentrators with a bottom-mounted（BM-LSCs）photovoltaic（PV） cell are fabricated by using a mixture of Lumogen Red 305 and Yellow 083 fluorescent dyes and a commercial monocrystalline silicon cell. The fabricated LSC with dye concentrations of 40 ppm has the highest power gain of 1.50, which is the highest value reported for the dye-doped PMMA plate LSCs. The power gain of the LSC comes from three parts： the waveguide light, the transmitted light, and the reflected light from a white reflector, and their contributions are analyzed quantitatively. The results suggest that the BM-LSCs have great potential for future low-cost PV devices in building integrated PV applications.展开更多
基金Projects(21376031,21075011)supported by the National Natural Science Foundation of ChinaProject(2012GK3058)supported by the Foundation of Hunan Provincial Science and Technology Department,China+2 种基金Project supported by the Postdoctoral Science Foundation of Central South University,ChinaProject(2014CL01)supported by the Foundation of Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,ChinaProject supported by the Innovation Experiment Program for University Students of Changsha University of Science and Technology,China
文摘Flash point is a primary property used to determine the fire and explosion hazards of a liquid. New group contribution-based models were presented for estimation of the flash point of alkanes by the use of multiple linear regression(MLR)and artificial neural network(ANN). This simple linear model shows a low average relative deviation(AARD) of 2.8% for a data set including 50(40 for training set and 10 for validation set) flash points. Furthermore, the predictive ability of the model was evaluated using LOO cross validation. The results demonstrate ANN model is clearly superior both in fitness and in prediction performance.ANN model has only the average absolute deviation of 2.9 K and the average relative deviation of 0.72%.
基金supported by the National Natural Science Foundation of China(No.51608298)the Open Research Fund Program of Cultivation Project of Double First-Class Disciplines of Environmental Science and Engineering,Beijing Technology&Business University(BTBU,ESE2022YB07)the Graduate Research and Practice Projects of Minzu University of China.We would like to thank Editage for English language editing。
文摘Direct membrane filtration(DMF)is a popular option for raw sewage pre-concentration for the subsequent organic resource recovery.It undergoes rapid and severe fouling.To achieve a fundamental understanding of the contributions of key foulants to DMF,principal component analysis(PCA)using Fourier transform infrared spectroscopy(FTIR)was applied to identify three stages of DMF.Variance partitioning analysis(VPA)and partial least squares(PLS)were used to quantitatively determine the contributions of key foulants.Humic acid(HA)achieved the highest intersection contribution(40.5%)to the total variance of the increase in resistance.Meanwhile,HA and protein(PN)explained 20.1%in the middle stage of DMF.The overall marginal effect of HA accounted for 42.5%of the variance,in conjunction with an overall individual effect of 11.0%(which was the highest in the initial stage:15.1%).The variable importance in projection(VIP)of impact on the resistance increase of DMF were 1.16(PN),0.99(HA),and 0.82(polysaccharides,PS).HA&PN with a VIP value approaching or larger than one significantly influenced the resistance increase in DMF.Meanwhile,the VIP of impact on blocking model alteration were 1.03(PS),1.01(PN),and 0.96(HA).HA,PS,and PN were regarded as vital factors in the fouling mode alteration.PS drives the fouling mode in the initial stage,whereas HA&PN and PN play dominant roles in the middle and final stages.Measures targeting HA and PN removal can be adapted for the efficient and cost-effective fouling control of raw sewage DMF.
基金supported by the National Key Research and Development Program(Grant No.2021YFC3200204)the National Natural Science Foundation of China(Grant Nos.52025093&52061125101)。
文摘From 1956 to 2016,Hai River Basin suffered the most severe surface water resource attenuation among the 10 first-class river basins in China.Based on the surface water circulation process,and evolving characteristics of precipitation and underlying surface in Hai River Basin,this study attributed the causes of surface water resource attenuation to six primary impact factors,analyzed each factor's quantitative contribution,and revealed four patterns of surface water resource attenuation in Hai River Basin.The pattern of the dominant factor:comparing the 1980–2000 period with the 1956–1979period,the variation of precipitation is the dominant factor of which contribution is 7 billion m^(3),accounting for 59%of total11.7 billion m^(3);comparing the 2001–2016 period with the 1956–1979 period,the increasing of vegetation cover in mountainous area is the dominant factor of which contribution is 2.78 billion m3,accounting for 51%of total 4.9 billion m^(3).The pattern of spatial distributions:comparing the 2001–2016 period with the 1956–1979 period,mountainous areas were more affected by increasing vegetation cover which for example contributed 42%in Luan River Basin mountainous;the plains were more impacted by farmland ridge interception which for example contributed 51%in Beisi River Basin plains.The pattern of attenuation trend:comparing the 2001–2016 period with the 1980–2000 period,surface water resources in mountainous areas continued to decline,owing to the increasing water consumption of large-scale vegetation restoration,while the influence of the underlying surface changes on surface water resources in plains areas tended to remain stable.The pattern of reversible change:among factors led to surface water resource attenuation,the human activity,including vegetation cover increase,farmland ridge interception,and urbanization expansion,contributed 36%of the attenuation,which resulted in the variation of precipitation-runoff relation.This study improved the traditional attribution classification model of climate change and human activity and analyzed the causes and contributions of water resource attenuation in Hai River Basin based on the water circulation process,which can provide scientific support for the development of water resource management in the basin.
基金supported by the National Nature Science Foundation of China(No.U1632273)the Chinese Academy of Sciences(No.CX3430000001)
文摘Polymethyl methacrylate（PMMA） plate luminescent solar concentrators with a bottom-mounted（BM-LSCs）photovoltaic（PV） cell are fabricated by using a mixture of Lumogen Red 305 and Yellow 083 fluorescent dyes and a commercial monocrystalline silicon cell. The fabricated LSC with dye concentrations of 40 ppm has the highest power gain of 1.50, which is the highest value reported for the dye-doped PMMA plate LSCs. The power gain of the LSC comes from three parts： the waveguide light, the transmitted light, and the reflected light from a white reflector, and their contributions are analyzed quantitatively. The results suggest that the BM-LSCs have great potential for future low-cost PV devices in building integrated PV applications.
