At present,the leakage rate of the water distribution network in China is still high,and the waste of water resources caused by water distribution network leakage is quite serious every year.Therefore,the location of ...At present,the leakage rate of the water distribution network in China is still high,and the waste of water resources caused by water distribution network leakage is quite serious every year.Therefore,the location of pipeline leakage is of great significance for saving water resources and reducing economic losses.Acoustic emission technology is the most widely used pipeline leak location technology.The traditional non-stationary random signal de-noising method mainly relies on the estimation of noise parameters,ignoring periodic noise and components unrelated to pipeline leakage.Aiming at the above problems,this paper proposes a leak location method for water supply pipelines based on a multivariate variational mode decomposition algorithm.This method combines the two parameters of the energy loss coefficient and the correlation coefficient between adjacent modes,and adaptively determines the decomposition mode number K according to the characteristics of the signal itself.According to the correlation coefficient,the effective component is selected to reconstruct the signal and the cross-correlation time delay is estimated to determine the location of the pipeline leakage point.The experimental results show that this method has higher accuracy than the cross-correlation method based on VMD and the cross-correlation method based on EMD,and the average relative positioning error is less than 2.2%.展开更多
The water-supplying capacity of two agricultural soils, red soil in Jiangxi Province and meadow soil in Henan Province, was assessed mainly using physical investigations. The reticulated mottting horizon in the red so...The water-supplying capacity of two agricultural soils, red soil in Jiangxi Province and meadow soil in Henan Province, was assessed mainly using physical investigations. The reticulated mottting horizon in the red soil was a horizon limiting roots distribution due to its high density and hardness in structure and low pH (pH 5.05). The resistance of the red soil to drought hazard was poor because of its low water-supply capacity and poor hydraulic conductivity. The meadow soil had superior profile infiltration to that of the red soil and great available water-storage capacity) which resulted in low run-off loss, especially in the wheat-growth season. It was difficult for water stored in the deep layers of the meadow soil to reach the surface due to the low unsaturated hydraulic conductivity of its clay-rich horizon in subsoil. However, water stored in deep layers was still available because the roots could extend to the deep layers due to the relatively low density in soil structure.展开更多
A 5--year experiment on water balance was conducted in a flat rainfed wheat field with an area of 66 m ×100 m in Fengqiu,Henan Province,China,Results of the experiment showed that the correlation between wheat y...A 5--year experiment on water balance was conducted in a flat rainfed wheat field with an area of 66 m ×100 m in Fengqiu,Henan Province,China,Results of the experiment showed that the correlation between wheat yield and water consumption was not significant ,but that between wheat yield and the ratio of Water supply to Penman evaporation was significant ,foolowing a parabolic curve.The water consumption process, as well as the growing season of wheat plant,could be diveded inot three peridos.The first(154 days) was vegetative growth period ,during which the water consumption,accounted for 35% of the total;the second (65 days)reproductive growth period ,uring which the water consumption occupied 57%,indicating the importance of water consumption in this period;and the third(5-9 days) maturation period,during,which water supply was not important to yield formation.According to the statistics of meteorological data over the years in this region,the hydrological conditions of the five seasons covered a probability range of 74.8%. the results(3.46-5.63 t ha^-1)indicated taht the productivity of the wheat field under rainfed conditions in this region had a dergee of confidence of 74.8%.展开更多
Soil water is a key factor limiting plant growth in water-limited regions. Without limit of soil water used by plants, soil degradation in the form of soil desiccation is easy to take place in the perennial forestland...Soil water is a key factor limiting plant growth in water-limited regions. Without limit of soil water used by plants, soil degradation in the form of soil desiccation is easy to take place in the perennial forestland and grassland with too higher density or productivity. Soil water resources use limit (SWRUL) is the lowest control limit of soil water resources which is used by plants in those regions. It can be defined as soil water storage within the maximum infiltration depth in which all of soil layers belong to dried soil layers. In this paper, after detailed discussion of characteristics of water resources and the relationship between soil water and plant growth in the Loess Plateau, the definition, quantitative method, and practical applications of SWRUL are introduced. Henceforth, we should strengthen the study of SWRUL and have a better understanding of soil water resources. All those are of great importance for designing effective restoration project and sustainable management of soil water resources in water- limited regions in the future.展开更多
The coupling relation exists in water and soil conser-vation and economic-social development. The article analyses the relation of soil and water conservation and economic-social development stages as well as the coup...The coupling relation exists in water and soil conser-vation and economic-social development. The article analyses the relation of soil and water conservation and economic-social development stages as well as the coupling analytical method. Then calculates the expecting income by dispersing Markov decision and calculates the correlation coefficient and the re-lationship degree. The article obtains the relationship of soil and water conservation investments and all kinds of incomes. Finally, it analyzes the important meaning in socio-economic development of water and soil conservation.展开更多
It is important to study the soluble organic N （SON） extracted during water-logged incubation for evaluating soil Nsupplying capacity. Soil initial SON and mineral N （Nmin）, cumulative soluble organic N and NH4＋-...It is important to study the soluble organic N （SON） extracted during water-logged incubation for evaluating soil Nsupplying capacity. Soil initial SON and mineral N （Nmin）, cumulative soluble organic N and NH4＋-N in leachates during water-logged incubation, mineralization potentials of both easily decomposable N （ND） and resistant N （NR）, and their relationships with N uptake by crop in pot experiment were investigated by using 10 kinds of farmland soils with widely different physical and chemical properties on the Loess Plateau, China, and the effects of SON on evaluating soil Nsupplying capacity were studied. The results showed that the average content of initial SON （23.9 mg kg^-1） of 10 soils was 28.8% of initial total soluble N and 2.4% of soil total N. The percentage of cumulative SON in leaching total soluble N （118.1 mg kg^-1 was 46.4%, higher than the percentage of initial SON （28.8%）, and almost close to the percentage of cumulative NH4^＋-N in the leachates. ND had close correlation with total N, and the correlation coefficients were 0.92 （P 〈 0.01, excluding SON in estimating ND） and 0.88 （P 〈 0.01, including SON in estimating ND）, respectively. N mineralization potential and mineralization rate constant were different with the soil types. ND of Los-Orthic Entisols and Ust-Sandiic Entisols were lower than that of Eum-Orthrosols. Mineralization rate constant for the fast decomposable N-fraction （kD） decreased and the mineralization rate constant of resistant materials （kR） increased when SON was taken into account. Cumulative NH4^＋-N was a better evaluation index of soil N-supplying capacity, and it is not only suitable for the first season crops but also for two successive season crops. Cumulative SON alone was not a satisfactory index for the potential of mineralizable N. But it would be more accurate for ND in revealing the potential mineralizable N when SON was taken into account. Cumulative TSN, to some extent, could also be taken as an index for the potential mineralizable N. Cumulative NH4＋-N, total soluble N, and ND were good indexes for estimating soil potential mineralizable N, especially for soils of two successive season crops. And cumulative total soluble N and ND in evaluating the permanence of soil N-supply is of greater significance when SON was included.展开更多
Humans spend 64% - 94% of their time indoors;therefore, indoor air quality is very important for potential exposure to volatile organic compounds (VOC). The source of VOC in the subsurface may come from accidental or ...Humans spend 64% - 94% of their time indoors;therefore, indoor air quality is very important for potential exposure to volatile organic compounds (VOC). The source of VOC in the subsurface may come from accidental or intentional releases, leaking landfills or leaking underground and above-ground storage tanks. Once these contaminants are present near or beneath buildings, they may move as a vapour through soil gas and enter the building. A large number of vapour intrusion (VI) algorithms have been published in peer-reviewed publications that link indoor VOC concentrations to the contamination of soils. These models typically include phase partitioning calculations of VOC based on Henry’s law to estimate the concentration of a particular contaminant in soil gas. This paper presents the results from a series of laboratory experiments concerning the use of the Henry’s Law constant for the calculation of toluene concentrations in equilibrium between ground water and soil air. A series of column experiments were conducted with various toluene concentrations in artificial (ground) water to contrast the predicted and observed (soil) air concentrations. The experiments which exclude soil material show a toluene fugacity behaviour roughly in line with Henry’s law whereas the experiments which include soil material result in equilibrium soil concentrations which were around one order-of-magnitude lower than was expected from a Henry Law-based estimation. It is concluded that for toluene inclusion of Henry’s Law in VI algorithms does not provide an adequate description of volatilisation in soils and may lead to an overestimation of health risk. Instead, a model based on a simple description of the relevant intermolecular interactions could be explored.展开更多
Pore water pressure has an important influence on mechanical properties of soil.The authors studied the characteristics of pore water pressure dissipating of mucky soil under consolidated-drained condition by using re...Pore water pressure has an important influence on mechanical properties of soil.The authors studied the characteristics of pore water pressure dissipating of mucky soil under consolidated-drained condition by using refitted triaxial instrument and analyzed the variation of pore pressure coefficient with consolidation pressure.The results show that the dissipating of pore water pressure behaves in different ways depends on different styles of loading.What is more,the pore water pressure coefficient of mucky soil is less than 1.As the compactness of soil increases and moisture content reduces,the value of B reduces.There is a staggered dissipating in the process of consolidation,in which it is a mutate point when U/P is 80%.It is helpful to establish the pore water pressure model and study the strength-deformation of soil in process of consolidation.展开更多
With the increasing researches on geotechnical properties of the diesel contaminated soil( DCS),the water content measured is indispensable part during the early period. In this study,the relative error of water conte...With the increasing researches on geotechnical properties of the diesel contaminated soil( DCS),the water content measured is indispensable part during the early period. In this study,the relative error of water content measurement using the traditional method is as high as 20. 78%,which is no longer suitable for contaminated soil. Through a series of tests to measure the loss coefficient of diesel in the drying time,the authors finally proposed a modified calculation formula for test samples. The results show that the maximum relative error calculated by using the modified formula is 0. 96%,far lower than that of traditional formula,which can provide accurate data for further study of diesel contaminated soil.展开更多
基金supported by the three funds:Industry-University-research Project of Anhui Jianzhu University HYB20210116National Key Research and Development Project of China No.2017YFC0704100(entitled New Generation Intelligent Building Platform Techniques)Research Project of Anhui Jianzhu University jy2021-c-017(Project Name:Research and Application ofWater Distribution Network Leakage Detection System Based on DMA Partition).
文摘At present,the leakage rate of the water distribution network in China is still high,and the waste of water resources caused by water distribution network leakage is quite serious every year.Therefore,the location of pipeline leakage is of great significance for saving water resources and reducing economic losses.Acoustic emission technology is the most widely used pipeline leak location technology.The traditional non-stationary random signal de-noising method mainly relies on the estimation of noise parameters,ignoring periodic noise and components unrelated to pipeline leakage.Aiming at the above problems,this paper proposes a leak location method for water supply pipelines based on a multivariate variational mode decomposition algorithm.This method combines the two parameters of the energy loss coefficient and the correlation coefficient between adjacent modes,and adaptively determines the decomposition mode number K according to the characteristics of the signal itself.According to the correlation coefficient,the effective component is selected to reconstruct the signal and the cross-correlation time delay is estimated to determine the location of the pipeline leakage point.The experimental results show that this method has higher accuracy than the cross-correlation method based on VMD and the cross-correlation method based on EMD,and the average relative positioning error is less than 2.2%.
文摘The water-supplying capacity of two agricultural soils, red soil in Jiangxi Province and meadow soil in Henan Province, was assessed mainly using physical investigations. The reticulated mottting horizon in the red soil was a horizon limiting roots distribution due to its high density and hardness in structure and low pH (pH 5.05). The resistance of the red soil to drought hazard was poor because of its low water-supply capacity and poor hydraulic conductivity. The meadow soil had superior profile infiltration to that of the red soil and great available water-storage capacity) which resulted in low run-off loss, especially in the wheat-growth season. It was difficult for water stored in the deep layers of the meadow soil to reach the surface due to the low unsaturated hydraulic conductivity of its clay-rich horizon in subsoil. However, water stored in deep layers was still available because the roots could extend to the deep layers due to the relatively low density in soil structure.
文摘A 5--year experiment on water balance was conducted in a flat rainfed wheat field with an area of 66 m ×100 m in Fengqiu,Henan Province,China,Results of the experiment showed that the correlation between wheat yield and water consumption was not significant ,but that between wheat yield and the ratio of Water supply to Penman evaporation was significant ,foolowing a parabolic curve.The water consumption process, as well as the growing season of wheat plant,could be diveded inot three peridos.The first(154 days) was vegetative growth period ,during which the water consumption,accounted for 35% of the total;the second (65 days)reproductive growth period ,uring which the water consumption occupied 57%,indicating the importance of water consumption in this period;and the third(5-9 days) maturation period,during,which water supply was not important to yield formation.According to the statistics of meteorological data over the years in this region,the hydrological conditions of the five seasons covered a probability range of 74.8%. the results(3.46-5.63 t ha^-1)indicated taht the productivity of the wheat field under rainfed conditions in this region had a dergee of confidence of 74.8%.
文摘Soil water is a key factor limiting plant growth in water-limited regions. Without limit of soil water used by plants, soil degradation in the form of soil desiccation is easy to take place in the perennial forestland and grassland with too higher density or productivity. Soil water resources use limit (SWRUL) is the lowest control limit of soil water resources which is used by plants in those regions. It can be defined as soil water storage within the maximum infiltration depth in which all of soil layers belong to dried soil layers. In this paper, after detailed discussion of characteristics of water resources and the relationship between soil water and plant growth in the Loess Plateau, the definition, quantitative method, and practical applications of SWRUL are introduced. Henceforth, we should strengthen the study of SWRUL and have a better understanding of soil water resources. All those are of great importance for designing effective restoration project and sustainable management of soil water resources in water- limited regions in the future.
文摘The coupling relation exists in water and soil conser-vation and economic-social development. The article analyses the relation of soil and water conservation and economic-social development stages as well as the coupling analytical method. Then calculates the expecting income by dispersing Markov decision and calculates the correlation coefficient and the re-lationship degree. The article obtains the relationship of soil and water conservation investments and all kinds of incomes. Finally, it analyzes the important meaning in socio-economic development of water and soil conservation.
基金National Natural Science Foundation of China （90502006）.
文摘It is important to study the soluble organic N （SON） extracted during water-logged incubation for evaluating soil Nsupplying capacity. Soil initial SON and mineral N （Nmin）, cumulative soluble organic N and NH4＋-N in leachates during water-logged incubation, mineralization potentials of both easily decomposable N （ND） and resistant N （NR）, and their relationships with N uptake by crop in pot experiment were investigated by using 10 kinds of farmland soils with widely different physical and chemical properties on the Loess Plateau, China, and the effects of SON on evaluating soil Nsupplying capacity were studied. The results showed that the average content of initial SON （23.9 mg kg^-1） of 10 soils was 28.8% of initial total soluble N and 2.4% of soil total N. The percentage of cumulative SON in leaching total soluble N （118.1 mg kg^-1 was 46.4%, higher than the percentage of initial SON （28.8%）, and almost close to the percentage of cumulative NH4^＋-N in the leachates. ND had close correlation with total N, and the correlation coefficients were 0.92 （P 〈 0.01, excluding SON in estimating ND） and 0.88 （P 〈 0.01, including SON in estimating ND）, respectively. N mineralization potential and mineralization rate constant were different with the soil types. ND of Los-Orthic Entisols and Ust-Sandiic Entisols were lower than that of Eum-Orthrosols. Mineralization rate constant for the fast decomposable N-fraction （kD） decreased and the mineralization rate constant of resistant materials （kR） increased when SON was taken into account. Cumulative NH4^＋-N was a better evaluation index of soil N-supplying capacity, and it is not only suitable for the first season crops but also for two successive season crops. Cumulative SON alone was not a satisfactory index for the potential of mineralizable N. But it would be more accurate for ND in revealing the potential mineralizable N when SON was taken into account. Cumulative TSN, to some extent, could also be taken as an index for the potential mineralizable N. Cumulative NH4＋-N, total soluble N, and ND were good indexes for estimating soil potential mineralizable N, especially for soils of two successive season crops. And cumulative total soluble N and ND in evaluating the permanence of soil N-supply is of greater significance when SON was included.
文摘Humans spend 64% - 94% of their time indoors;therefore, indoor air quality is very important for potential exposure to volatile organic compounds (VOC). The source of VOC in the subsurface may come from accidental or intentional releases, leaking landfills or leaking underground and above-ground storage tanks. Once these contaminants are present near or beneath buildings, they may move as a vapour through soil gas and enter the building. A large number of vapour intrusion (VI) algorithms have been published in peer-reviewed publications that link indoor VOC concentrations to the contamination of soils. These models typically include phase partitioning calculations of VOC based on Henry’s law to estimate the concentration of a particular contaminant in soil gas. This paper presents the results from a series of laboratory experiments concerning the use of the Henry’s Law constant for the calculation of toluene concentrations in equilibrium between ground water and soil air. A series of column experiments were conducted with various toluene concentrations in artificial (ground) water to contrast the predicted and observed (soil) air concentrations. The experiments which exclude soil material show a toluene fugacity behaviour roughly in line with Henry’s law whereas the experiments which include soil material result in equilibrium soil concentrations which were around one order-of-magnitude lower than was expected from a Henry Law-based estimation. It is concluded that for toluene inclusion of Henry’s Law in VI algorithms does not provide an adequate description of volatilisation in soils and may lead to an overestimation of health risk. Instead, a model based on a simple description of the relevant intermolecular interactions could be explored.
文摘Pore water pressure has an important influence on mechanical properties of soil.The authors studied the characteristics of pore water pressure dissipating of mucky soil under consolidated-drained condition by using refitted triaxial instrument and analyzed the variation of pore pressure coefficient with consolidation pressure.The results show that the dissipating of pore water pressure behaves in different ways depends on different styles of loading.What is more,the pore water pressure coefficient of mucky soil is less than 1.As the compactness of soil increases and moisture content reduces,the value of B reduces.There is a staggered dissipating in the process of consolidation,in which it is a mutate point when U/P is 80%.It is helpful to establish the pore water pressure model and study the strength-deformation of soil in process of consolidation.
文摘With the increasing researches on geotechnical properties of the diesel contaminated soil( DCS),the water content measured is indispensable part during the early period. In this study,the relative error of water content measurement using the traditional method is as high as 20. 78%,which is no longer suitable for contaminated soil. Through a series of tests to measure the loss coefficient of diesel in the drying time,the authors finally proposed a modified calculation formula for test samples. The results show that the maximum relative error calculated by using the modified formula is 0. 96%,far lower than that of traditional formula,which can provide accurate data for further study of diesel contaminated soil.
