Water decoupling charge blasting excels in rock breaking,relying on its uniform pressure transmission and low energy dissipation.The water decoupling coefficients can adjust the contributions of the stress wave and qu...Water decoupling charge blasting excels in rock breaking,relying on its uniform pressure transmission and low energy dissipation.The water decoupling coefficients can adjust the contributions of the stress wave and quasi-static pressure.However,the quantitative relationship between the two contributions is unclear,and it is difficult to provide reasonable theoretical support for the design of water decoupling blasting.In this study,a theoretical model of blasting fracturing partitioning is established.The mechanical mechanism and determination method of the optimal decoupling coefficient are obtained.The reliability is verified through model experiments and a field test.The results show that with the increasing of decoupling coefficient,the rock breaking ability of blasting dynamic action decreases,while quasi-static action increases and then decreases.The ability of quasi-static action to wedge into cracks changes due to the spatial adjustment of the blast hole and crushed zone.The quasi-static action plays a leading role in the fracturing range,determining an optimal decoupling coefficient.The optimal water decoupling coefficient is not a fixed value,which can be obtained by the proposed theoretical model.Compared with the theoretical results,the maximum error in the model experiment results is 8.03%,and the error in the field test result is 3.04%.展开更多
A regional multiple objective water resource and economic optimization model was developed using a quantitative method of systematic analysis. Input to the model includes indexes of economic structure and development,...A regional multiple objective water resource and economic optimization model was developed using a quantitative method of systematic analysis. Input to the model includes indexes of economic structure and development, water resource utilization, wastewater and pollutant discharge, and investment in wastewater treatment. The model, which consists of production structure and industrial structure optimization modules, was applied to the Guanzhong region in the middle reaches of the Huanghe (Yellow) River basin in China. By evaluating several alternative production and industrialization schemes, the modal indicate that water pollution will get worsen though wastewater treatment improves if the economy continues to develop at the planned speed without structural adjustment. However, the results also show that not only economic goals but also water resource protection and pollution control targets can be achieved under an alternative, recommended production and industrial structure. This example illustrates that economic development and environmental protection can be improved coordinately by the regional multiple objective water resource and economic optimization model. It provides an operable approach to the simultaneous sustained development of water resources and economic growth.展开更多
Since the 1990s, the Yellow River stream has been temporarily interrupted for several years, which affects the development of society, the economy and human life, limits the economic potential of the drainage areas, a...Since the 1990s, the Yellow River stream has been temporarily interrupted for several years, which affects the development of society, the economy and human life, limits the economic potential of the drainage areas, and especially causes great harm to regions on the lower reaches. Based on the analysis of the relationship between the development of society and economy and water scarcity, the author thinks it is necessary to optimize and adjust the industrial structure that has extravagantly consumed enormous amounts of water, and to develop ecological agriculture, industry and tourism which are balanced with the ecological environment. Finally, the author puts forward several pieces of advice and countermeasures about how to build the economic systems by which water can be used economically.展开更多
To investigate the attitude-switching mechanisms of existing jet slotters,which integrate drilling,punching and slotting operations,and to improve its fracture ability,we used the power bond diagram theory to analyse ...To investigate the attitude-switching mechanisms of existing jet slotters,which integrate drilling,punching and slotting operations,and to improve its fracture ability,we used the power bond diagram theory to analyse the dynamic flow pressure,and force of slotters.A mathematical model was developed for the dynamic characteristics of slotter systems.Furthermore,to study the effect of the main characteristic parameters on the ability of the nozzle to erode sandstone,multi-orthogonal experiments were carried out.And the optimised slots were applied in later practical operations.The research results show that the inlet fluid passed through the time-varying orifice to generate pressure differential thrust,which overcame the spring force,pushed the valve core to open the side nozzle,and closed the rear cavity channel thereby realising the switch of the slotter attitude.An optimal plan was established to balance the diameter,depth,and volume of punching,and a rock-breaking plan was developed for the slotter.Subsequently,the optimised water jet slotter was practically used in coal seam gas drainage.Compared with conventional dense drilling,water jet slotting technology significantly improves the ability,efficiency,and effect of increasing the permeability of the coal seam.展开更多
With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The...With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The areal differentiation of agricultural products virtual water is obvious. Comparison with the agricultural products virtual water from 1995 to 2007 in China shows an increase in the first ten vears and a little decrease in recent years. There has been a tendency of increase all the time in Northeast and Northwest. but a decrease after an increase firstly in other regions. The virtual water offood crops is the maximum which accounts for more than 70% in China. and that of vegetables is in a fast growth. The proportion of agricultural products virtual water to the total water resources in each region has a large difference, showing the imbalance of agricultural water in different regions, which accounts for 50%-90% in Northeast, and 125%-185% in North China. Under the guidance of virtual water strategy, based on the differences of resource endowment, each region should adjust agricultural structure, decide production by water, and select water suitable crops. In water-rich region, agricultural produets of high water consumption should be planted appropriately, which will make full use of the abundant local water resources. In water-shortage region the crop production of high water consumption and low efficiency should be depressed, and that of low water consumption and high efficiency should be supported and increased. It will achieve reasonable disposition of water resources, promote ecological restoration and environmental protection, as welt as ensure food security.展开更多
Two varieties of winter wheat,Bei Nong 2(B. N. 2)and Jing 411(J. 411),were selected for osmotic adjustment study. At wheat growing stages,from recovery period to mature period,leaf relative water content(LRWC) ,water ...Two varieties of winter wheat,Bei Nong 2(B. N. 2)and Jing 411(J. 411),were selected for osmotic adjustment study. At wheat growing stages,from recovery period to mature period,leaf relative water content(LRWC) ,water potential(LWP)and saturated osmotic potential (LSOP) were positively correlated to soil relative water content (SRWC) and decreased as SRWC descended at each growth stage,and the decreasing range exhibited B. N. 2【J. 411. The turgor pressure(TP)of both the varieties decreased less than LRWC and LWP. It was shown that both varieties had a osmotic adjustment ability(OAA) ,and the decreasing range presented B. N. 2【J. 411. Both the varieties had a TP tubercle in TP vs SRWC graph at heading and filling stages,and their OAA was the strongest at these two stages.展开更多
During gel treatments for fractures, the leak-off behavior of gelant has a great effect on the water shut-off performance of gel. Experiments were carried out using a polymer/chromium(Cr^(3+)) gel system to explore th...During gel treatments for fractures, the leak-off behavior of gelant has a great effect on the water shut-off performance of gel. Experiments were carried out using a polymer/chromium(Cr^(3+)) gel system to explore the leak-off behavior and the water shut-off performance of gel in fractured media. Results of the gelant leak-off study show that the gelant leak-off from fracture into matrix contributes to the formation of the gelant leak-off layer during the gelant injection. Moreover, because of the gradual formation of the gelant leak-off layer along fracture, the initial leak-off ratio of gelant is relatively high, but it declines and finally levels off with the increase of the injection volume. The polymer concentration of gelant has a great effect on the chromium output in fluids produced from fractures. With the increase of the polymer concentration, the chromium concentration first decreases and then increases, and the leak-off depth of gelant into matrix is gradually reduced. Results of the water shut-off study present that the decrease of the chromium concentration inside the fracture greatly reduces the water shut-off performance after the gel formation. Therefore, because of the relatively high degree of chromium leak-off, enough injection volume of gelant is essential to ensure the sufficient chromium concentration inside the fracture and to further achieve a favorable water shut-off performance. On the premise of gel strength assurance inside the fracture, the water shut-off performance of gel gradually declines with the extension of the distance from the fracture inlet, and different leak-off degrees of gelant along the fracture are responsible for this phenomenon. Therefore, a proper degree of gelant leak-off contributes to enhancing the water shut-off performance of gel for fractures.展开更多
Salinity is a major stress that adversely affects growth and productivity in plants. There are species that tolerate this stresswithin the genus Atriplex. Four species, A. lampa, A. crenatifolia, A. nummularia and A. ...Salinity is a major stress that adversely affects growth and productivity in plants. There are species that tolerate this stresswithin the genus Atriplex. Four species, A. lampa, A. crenatifolia, A. nummularia and A. argentina were compared for their ionaccumulation and water relations under saline conditions. A greenhouse study was conducted by irrigating the four species with NaCIsolutions at concentrations 0%, 1%, 2% and 4% starting when plants were six months old. Plants were harvested 45 d after startingthe salinity treatments and analyzed for their ion contents. In the four Atriplex species, Na^＋ and Cl^- contents in plants increased, whileCa^2＋ and Mg^2＋ decreased with the increase of salinity in the irrigation solution. The results suggested that A. argentina and A.nummularia were able to maintain a higher leaf relative water content （RWC） at low leaf water potential, which was associated witha greater capacity of osmotic adjustment. A. lampa showed lower ion accumulation and minor osmotic adjustment than the otherspecies. It can be concluded that the accumulation of ions favors the lower osmotic potential and contributes to osmotic adjustment inthese halophytes.展开更多
In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied...In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied increasingly in the water network, and in order to reflect the network operational condition more accurately, a new water network macroscopic model is developed by taking the auto-control adjusting valve opening state into consideration. Then for highly correlated or collinear independent variables in the model, the partial least squares (PLS) regression method provides a model solution which can distinguish between the system information and the noisy data. Finally, a hypothetical water network is introduced for validating the model. The simulation results show that the relative error is less than 5.2%, indicating that the model is efficient and feasible, and has better generalization performance.展开更多
Water markets even though not perfect and require a lot of effort to establish are considered as a robust tool to address water management issues around the world. However, the existing literature does not provide an ...Water markets even though not perfect and require a lot of effort to establish are considered as a robust tool to address water management issues around the world. However, the existing literature does not provide an optimal water resource management policy. To create a perfect water market, the government needs to identify the potential number of suppliers/producers and consumers of water against various extraction/supply/production rates of water, i.e., to identify a supply and a demand curve for number of suppliers/producers of water against each production rate in economy. This article presents a theory which is practically applicable for an optimal dynamical water resource management policy (JEL H20, H23, H27).展开更多
Metal-organic frameworks(MOFs)have been developed as an ideal platform for exploration of the relationship between intrinsic structure and catalytic activity,but the limited catalytic activity and stability has hamper...Metal-organic frameworks(MOFs)have been developed as an ideal platform for exploration of the relationship between intrinsic structure and catalytic activity,but the limited catalytic activity and stability has hampered their practical use in water splitting.Herein,we develop a bond length adjustment strategy for optimizing naphthalene-based MOFs that synthesized by acid etching Co-naphthalenedicarboxylic acid-based MOFs(donated as AE-CoNDA)to serve as efficient catalyst for water splitting.AE-CoNDA exhibits a low overpotential of 260 mV to reach 10 mA cm^(−2)and a small Tafel slope of 62 mV dec^(−1)with excellent stability over 100 h.After integrated AE-CoNDA onto BiVO_(4),photocurrent density of 4.3 mA cm^(−2)is achieved at 1.23 V.Experimental investigations demonstrate that the stretched Co-O bond length was found to optimize the orbitals hybridization of Co 3d and O 2p,which accounts for the fast kinetics and high activity.Theoretical calculations reveal that the stretched Co-O bond length strengthens the adsorption of oxygen-contained intermediates at the Co active sites for highly efficient water splitting.展开更多
基金funded by the National Natural Science Foundation of China(No.42372331)the Henan Excellent Youth Science Fund Project(No.242300421145)the Colleges and Universities Youth and Innovation Science and Technology Support Plan of Shandong Province(No.2021KJ024).
文摘Water decoupling charge blasting excels in rock breaking,relying on its uniform pressure transmission and low energy dissipation.The water decoupling coefficients can adjust the contributions of the stress wave and quasi-static pressure.However,the quantitative relationship between the two contributions is unclear,and it is difficult to provide reasonable theoretical support for the design of water decoupling blasting.In this study,a theoretical model of blasting fracturing partitioning is established.The mechanical mechanism and determination method of the optimal decoupling coefficient are obtained.The reliability is verified through model experiments and a field test.The results show that with the increasing of decoupling coefficient,the rock breaking ability of blasting dynamic action decreases,while quasi-static action increases and then decreases.The ability of quasi-static action to wedge into cracks changes due to the spatial adjustment of the blast hole and crushed zone.The quasi-static action plays a leading role in the fracturing range,determining an optimal decoupling coefficient.The optimal water decoupling coefficient is not a fixed value,which can be obtained by the proposed theoretical model.Compared with the theoretical results,the maximum error in the model experiment results is 8.03%,and the error in the field test result is 3.04%.
文摘A regional multiple objective water resource and economic optimization model was developed using a quantitative method of systematic analysis. Input to the model includes indexes of economic structure and development, water resource utilization, wastewater and pollutant discharge, and investment in wastewater treatment. The model, which consists of production structure and industrial structure optimization modules, was applied to the Guanzhong region in the middle reaches of the Huanghe (Yellow) River basin in China. By evaluating several alternative production and industrialization schemes, the modal indicate that water pollution will get worsen though wastewater treatment improves if the economy continues to develop at the planned speed without structural adjustment. However, the results also show that not only economic goals but also water resource protection and pollution control targets can be achieved under an alternative, recommended production and industrial structure. This example illustrates that economic development and environmental protection can be improved coordinately by the regional multiple objective water resource and economic optimization model. It provides an operable approach to the simultaneous sustained development of water resources and economic growth.
文摘Since the 1990s, the Yellow River stream has been temporarily interrupted for several years, which affects the development of society, the economy and human life, limits the economic potential of the drainage areas, and especially causes great harm to regions on the lower reaches. Based on the analysis of the relationship between the development of society and economy and water scarcity, the author thinks it is necessary to optimize and adjust the industrial structure that has extravagantly consumed enormous amounts of water, and to develop ecological agriculture, industry and tourism which are balanced with the ecological environment. Finally, the author puts forward several pieces of advice and countermeasures about how to build the economic systems by which water can be used economically.
基金supported by the National Natural Science Foundation Outstanding Youth Fund(No.51625401)the Chongqing Natural Science Foundation(No.cstc2018jcyjAX0542)the Program for Changjiang Scholars and Innovative Research Team in Chongqing University(No.IRT17R112).
文摘To investigate the attitude-switching mechanisms of existing jet slotters,which integrate drilling,punching and slotting operations,and to improve its fracture ability,we used the power bond diagram theory to analyse the dynamic flow pressure,and force of slotters.A mathematical model was developed for the dynamic characteristics of slotter systems.Furthermore,to study the effect of the main characteristic parameters on the ability of the nozzle to erode sandstone,multi-orthogonal experiments were carried out.And the optimised slots were applied in later practical operations.The research results show that the inlet fluid passed through the time-varying orifice to generate pressure differential thrust,which overcame the spring force,pushed the valve core to open the side nozzle,and closed the rear cavity channel thereby realising the switch of the slotter attitude.An optimal plan was established to balance the diameter,depth,and volume of punching,and a rock-breaking plan was developed for the slotter.Subsequently,the optimised water jet slotter was practically used in coal seam gas drainage.Compared with conventional dense drilling,water jet slotting technology significantly improves the ability,efficiency,and effect of increasing the permeability of the coal seam.
基金supported by National Natural Science Foundation of China (Grant No. 40471034)Social Sciences Project of Educational Commission of Jilin Province
文摘With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The areal differentiation of agricultural products virtual water is obvious. Comparison with the agricultural products virtual water from 1995 to 2007 in China shows an increase in the first ten vears and a little decrease in recent years. There has been a tendency of increase all the time in Northeast and Northwest. but a decrease after an increase firstly in other regions. The virtual water offood crops is the maximum which accounts for more than 70% in China. and that of vegetables is in a fast growth. The proportion of agricultural products virtual water to the total water resources in each region has a large difference, showing the imbalance of agricultural water in different regions, which accounts for 50%-90% in Northeast, and 125%-185% in North China. Under the guidance of virtual water strategy, based on the differences of resource endowment, each region should adjust agricultural structure, decide production by water, and select water suitable crops. In water-rich region, agricultural produets of high water consumption should be planted appropriately, which will make full use of the abundant local water resources. In water-shortage region the crop production of high water consumption and low efficiency should be depressed, and that of low water consumption and high efficiency should be supported and increased. It will achieve reasonable disposition of water resources, promote ecological restoration and environmental protection, as welt as ensure food security.
文摘Two varieties of winter wheat,Bei Nong 2(B. N. 2)and Jing 411(J. 411),were selected for osmotic adjustment study. At wheat growing stages,from recovery period to mature period,leaf relative water content(LRWC) ,water potential(LWP)and saturated osmotic potential (LSOP) were positively correlated to soil relative water content (SRWC) and decreased as SRWC descended at each growth stage,and the decreasing range exhibited B. N. 2【J. 411. The turgor pressure(TP)of both the varieties decreased less than LRWC and LWP. It was shown that both varieties had a osmotic adjustment ability(OAA) ,and the decreasing range presented B. N. 2【J. 411. Both the varieties had a TP tubercle in TP vs SRWC graph at heading and filling stages,and their OAA was the strongest at these two stages.
基金Project(51404280)supported by the National Natural Science Foundation of ChinaProject(2014D-5006-0203)supported by the Petro China Innovation Foundation,China
文摘During gel treatments for fractures, the leak-off behavior of gelant has a great effect on the water shut-off performance of gel. Experiments were carried out using a polymer/chromium(Cr^(3+)) gel system to explore the leak-off behavior and the water shut-off performance of gel in fractured media. Results of the gelant leak-off study show that the gelant leak-off from fracture into matrix contributes to the formation of the gelant leak-off layer during the gelant injection. Moreover, because of the gradual formation of the gelant leak-off layer along fracture, the initial leak-off ratio of gelant is relatively high, but it declines and finally levels off with the increase of the injection volume. The polymer concentration of gelant has a great effect on the chromium output in fluids produced from fractures. With the increase of the polymer concentration, the chromium concentration first decreases and then increases, and the leak-off depth of gelant into matrix is gradually reduced. Results of the water shut-off study present that the decrease of the chromium concentration inside the fracture greatly reduces the water shut-off performance after the gel formation. Therefore, because of the relatively high degree of chromium leak-off, enough injection volume of gelant is essential to ensure the sufficient chromium concentration inside the fracture and to further achieve a favorable water shut-off performance. On the premise of gel strength assurance inside the fracture, the water shut-off performance of gel gradually declines with the extension of the distance from the fracture inlet, and different leak-off degrees of gelant along the fracture are responsible for this phenomenon. Therefore, a proper degree of gelant leak-off contributes to enhancing the water shut-off performance of gel for fractures.
文摘Salinity is a major stress that adversely affects growth and productivity in plants. There are species that tolerate this stresswithin the genus Atriplex. Four species, A. lampa, A. crenatifolia, A. nummularia and A. argentina were compared for their ionaccumulation and water relations under saline conditions. A greenhouse study was conducted by irrigating the four species with NaCIsolutions at concentrations 0%, 1%, 2% and 4% starting when plants were six months old. Plants were harvested 45 d after startingthe salinity treatments and analyzed for their ion contents. In the four Atriplex species, Na^＋ and Cl^- contents in plants increased, whileCa^2＋ and Mg^2＋ decreased with the increase of salinity in the irrigation solution. The results suggested that A. argentina and A.nummularia were able to maintain a higher leaf relative water content （RWC） at low leaf water potential, which was associated witha greater capacity of osmotic adjustment. A. lampa showed lower ion accumulation and minor osmotic adjustment than the otherspecies. It can be concluded that the accumulation of ions favors the lower osmotic potential and contributes to osmotic adjustment inthese halophytes.
基金Supported by Tianjin Natural Science Foundation( No. 003611611).
文摘In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied increasingly in the water network, and in order to reflect the network operational condition more accurately, a new water network macroscopic model is developed by taking the auto-control adjusting valve opening state into consideration. Then for highly correlated or collinear independent variables in the model, the partial least squares (PLS) regression method provides a model solution which can distinguish between the system information and the noisy data. Finally, a hypothetical water network is introduced for validating the model. The simulation results show that the relative error is less than 5.2%, indicating that the model is efficient and feasible, and has better generalization performance.
文摘Water markets even though not perfect and require a lot of effort to establish are considered as a robust tool to address water management issues around the world. However, the existing literature does not provide an optimal water resource management policy. To create a perfect water market, the government needs to identify the potential number of suppliers/producers and consumers of water against various extraction/supply/production rates of water, i.e., to identify a supply and a demand curve for number of suppliers/producers of water against each production rate in economy. This article presents a theory which is practically applicable for an optimal dynamical water resource management policy (JEL H20, H23, H27).
基金supported by the National Key Research and Development Program of China (2022YFB4002100)the development project of Zhejiang Province's "Jianbing" and "Lingyan" (2023C01226)+4 种基金the National Natural Science Foundation of China (22278364, U22A20432, 22238008, 22211530045, and 22178308)the Fundamental Research Funds for the Central Universities (226-2022-00044 and 226-2022-00055)the Science Foundation of Donghai Laboratory (DH-2022ZY0009)the Startup Foundation for Hundred-Talent Program of Zhejiang UniversityScientific Research Fund of Zhejiang Provincial Education Department.
文摘Metal-organic frameworks(MOFs)have been developed as an ideal platform for exploration of the relationship between intrinsic structure and catalytic activity,but the limited catalytic activity and stability has hampered their practical use in water splitting.Herein,we develop a bond length adjustment strategy for optimizing naphthalene-based MOFs that synthesized by acid etching Co-naphthalenedicarboxylic acid-based MOFs(donated as AE-CoNDA)to serve as efficient catalyst for water splitting.AE-CoNDA exhibits a low overpotential of 260 mV to reach 10 mA cm^(−2)and a small Tafel slope of 62 mV dec^(−1)with excellent stability over 100 h.After integrated AE-CoNDA onto BiVO_(4),photocurrent density of 4.3 mA cm^(−2)is achieved at 1.23 V.Experimental investigations demonstrate that the stretched Co-O bond length was found to optimize the orbitals hybridization of Co 3d and O 2p,which accounts for the fast kinetics and high activity.Theoretical calculations reveal that the stretched Co-O bond length strengthens the adsorption of oxygen-contained intermediates at the Co active sites for highly efficient water splitting.
