As a crucial human activity,dam construction can profoundly impact the surface hydrology patterns.The Three Gorges Reservoir(TGR),as one of the largest hydraulic engineering projects in the world,has gained continuous...As a crucial human activity,dam construction can profoundly impact the surface hydrology patterns.The Three Gorges Reservoir(TGR),as one of the largest hydraulic engineering projects in the world,has gained continuous attention for its eco-hydrological effects.However,further investigation is necessary to understand the runoff and social impacts of the TGR on the Upper Yangtze River.This study first employed a modified SWAT model to simulate runoff,compared scenarios with and without the TGR,and finally evaluated water supply and demand in the Upper Yangtze River.The results showed a significant increasing trend in the surface water area of the Upper Yangtze River from 2000-2020.The modified SWAT model performs well in simulating the runoff,with Nash-Sutcliffe Efficiency and Percent Bias improved by 0.04-0.30 and 2-31.90,respectively.Scenario simulation results revealed that the TGR reduced seasonal differences in runoff.During the flood season,the runoff volume at the Yichang Station in the scenario with the TGR is lower than in the scenario without the TGR,peaking at 4500 m3/s.Conversely,in the dry season,the runoff volume of the scenario with TGR is higher,with a maximum increase of 1500 m3/s.The region exhibiting the greatest runoff variations is the Yangtze River's main stem in the Three Gorges Reservoir region.Besides,the TGR notably alleviated the water supply-demand imbalance in Chongqing during the winter and spring seasons,with a maximum increase of 0.16 in the supplydemand index.This study can contribute significantly to understanding the natural and social impacts of the TGR from the perspective of hydrological and scenario simulation.展开更多
High-volume fraction silicon particle-reinforced aluminium matrix composites(Si/Al)are increasingly applied in aerospace,radar communications,and large-scale integrated circuits because of their superior thermal condu...High-volume fraction silicon particle-reinforced aluminium matrix composites(Si/Al)are increasingly applied in aerospace,radar communications,and large-scale integrated circuits because of their superior thermal conductivity,wear resistance,and low thermal expansion coefficient.However,the abrasive and adhesive wear caused by the hard silicon reinforcement and the ductile aluminium matrix leads to significant tool wear,decreased machining efficiency,and compromised surface quality.This study combines theoretical analysis and cutting experiments to investigate polycrystalline diamond(PCD)tool wear during milling of 70 vol%Si/Al composite.A key contribution of this work is the development of a tool wear model that incorporates reinforcement particle characteristics,treating them as ellipsoidal structures,which enhances the accuracy of predicting abrasive and adhesive wear mechanisms.The model is based on abrasive and adhesive wear mechanisms,and can analyze the interaction between silicon particles,aluminium matrix,and tool components,thus providing deeper insights into PCD tool wear processes.Experimental validation of the model shows a good agreement with the results,with a mean deviation of approximately 10%.The findings on the tool wear mechanism reveal that,as tool wear progresses,the proportion of abrasive wear increases from 40%in the running-in stage to 75%in the rapid wear stage,while adhesive wear decreases.The optimal machining parameters of 120 m·min^(–1) cutting speed(v_(c))and 0.04 mm·z^(–1) feed rate(f_(z)),result in tool life of 33 min and surface roughness(S_(a))of 2.2μm.The study uncovers the variation patterns of abrasive and adhesive wear during the tool wear process,and the proposed model offers a robust framework for predicting tool wear during the machining of high-volume fraction Si/Al composites.The research findings also offer key insights for optimizing tool selection and machining parameters,advancing both the theoretical understanding and practical application of PCD tool wear.展开更多
To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’...To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’along the spiral trajectory,was proposed.From the kinematics analysis,it is found that the machining quality of micro-dimpled structures is highly dependent on the machining trajectory using spiral trajectory tool reciprocating motion.To reveal this causation,simulation modelling and experimental studies were carried out.A simulation model was developed to quantitatively and qualitatively investigate the influence of the trajectory discretization strategies(constant-angle and constant-arc length)and parameters(discrete angle,discrete arc length,and pitch)on surface texture and residual height of micro-dimpled structures.Subsequently,micro-dimpled structures were milled under different trajectory discretization strategies and parameters with spiral trajectory tool reciprocating motion.A comprehensive comparison between the milled results and simulation analysis was made based on geometry accuracy,surface morphology and surface roughness of milled dimples.Meanwhile,the errors and factors affecting the above three aspects were analyzed.The results demonstrate both the feasibility of the established simulation model and the machining capability of this machining way in milling high-quality micro-dimpled structures.Spiral trajectory tool reciprocating motion provides a new machining way for milling micro-dimpled structures and micro-dimpled functional surfaces.And an appropriate machining trajectory can be generated based on the optimized trajectory parameters,thus contributing to the improvement of machining quality and efficiency.展开更多
This article evaluates the transformative potential of large language models(LLMs)as patient education tools for managing inflammatory bowel disease.The discussion highlights their ability to deliver nuanced and perso...This article evaluates the transformative potential of large language models(LLMs)as patient education tools for managing inflammatory bowel disease.The discussion highlights their ability to deliver nuanced and personalized infor-mation,addressing limitations in traditional educational materials.Key consider-ations include the necessity for domain-specific fine-tuning to enhance accuracy,the adoption of robust evaluation metrics beyond readability,and the integration of LLMs with clinical decision support systems to improve real-time patient education.Ethical and accessibility challenges,such as algorithmic bias,data privacy,and digital literacy,are also examined.Recommendations emphasize the importance of interdisciplinary collaboration to optimize LLM integration,en-suring equitable access and improved patient outcomes.By advancing LLM technology,healthcare can empower patients with accurate and personalized information,enhancing engagement and disease management.展开更多
Modelling the hydrological balance in semi-arid zones is essential for effective water resource management,encompassing both surface water and groundwater.This study aims to model the monthly hydrological water cycle ...Modelling the hydrological balance in semi-arid zones is essential for effective water resource management,encompassing both surface water and groundwater.This study aims to model the monthly hydrological water cycle in the Wadi Mina upstream watershed(northwest Algeria)by applying the Soil and Water Assessment Tool(SWAT)hydrological model.SWAT modelling integrates spatial data such as the Digital Elevation Model(DEM),land use,soil types and various meteorological parameters including precipitation,maximum and minimum temperatures,relative humidity,solar radiation and wind speed.The SWAT model was calibrated and validated using data from January 2012 to December 2014,with a calibra-tion period from January 2012 to August 2013 and a validation period from September 2013 to December 2014.Sensitivity and parameter calibration were conducted using the SWAT-SA program,and model performance evaluation relied on comparing the observed discharge at the outlet of the basin with model-simulated discharge,assessed through statistical coefficients including Nash-Sutcliffe Efficiency(NSE),coefficient of determination(R2)and Percent Bias(PBAIS).Calibration results indicated favourable objec-tive function values(NSE=0.79,R2=0.93,PBAIS=-8.53%),although a slight decrease was observed during validation(NSE=0.69,R2=0.86,and PBAIS=-11.41%).The application of the SWAT model to the Wadi Mina upstream watershed highlighted its utility in simulating the spatial distribution of different components of the hydrological balance in this basin.The SWAT model revealed that approximately 71%of the precipitation in the basin evaporates,while only 29%contributes to surface runoff or infiltration into the soil.展开更多
Geometric error,mainly due to imperfect geometry and dimensions of machine components,is one of the major error sources of machine tools.Considering that geometric error has significant effects on the machining qualit...Geometric error,mainly due to imperfect geometry and dimensions of machine components,is one of the major error sources of machine tools.Considering that geometric error has significant effects on the machining quality of manufactured parts,it has been a popular topic for academic and industrial research for many years.A great deal of research work has been carried out since the 1970s for solving the problem and improving the machining accuracy.Researchers have studied how to measure,detect,model,identify,reduce,and compensate the geometric errors.This paper presents a thorough review of the latest research activities and gives an overview of the state of the art in understanding changes in machine tool performance due to geometric errors.Recent advances in measuring the geometrical errors of machine tools are summarized,and different kinds of error identification methods of translational axes and rotation axes are illustrated respectively.Besides,volumetric geometric error modeling,tracing,and compensation techniques for five-axis machine tools are emphatically introduced.Finally,research challenges in order to improve the volumetric accuracy of machine tools are also highlighted.展开更多
Hydrological modeling plays a crucial role in efficiently managing water resources and understanding the hydrologic behavior of watersheds. This study aims to simulate daily streamflow in the Godavari River Basin in M...Hydrological modeling plays a crucial role in efficiently managing water resources and understanding the hydrologic behavior of watersheds. This study aims to simulate daily streamflow in the Godavari River Basin in Maharashtra using the Soil and Water Assessment Tool (SWAT). SWAT is a process-based hydrological model used to predict water balance components, sediment levels, and nutrient contamination. In this research, we used integrated remote sensing and GIS data, including Digital Elevation Models (DEM), land use and land cover (LULC) maps, soil maps, and observed precipitation and temperature data, as input for developing the SWAT model to assess surface runoff in this large river basin. The Godavari River Basin under study was divided into 25 sub-basins, comprising 151 hydrological response units categorized by unique land cover, soil, and slope characteristics using the SWAT model. The model was calibrated and validated against observed runoff data for two time periods: 2003-2006 and 2007-2010 respectively. Model performance was assessed using the Nash-Sutcliffe efficiency (NSE) and the coefficient of determination (R2). The results show the effectiveness of the SWAT2012 model, with R2 value of 0.84 during calibration and 0.86 during validation. NSE values also ranged from 0.84 during calibration to 0.85 during validation. These findings enhance our understanding of surface runoff dynamics in the Godavari River Basin under study and highlight the suit-ability of the SWAT model for this region.展开更多
On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine tools.Laser tool setters play a crucial role in precisely me...On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine tools.Laser tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and diameter.As a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before use.However,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring rod.To address this issue,this study proposes a novel calibration method.Initially,the calibration mechanism of the laser beam axis is established.Based on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is established.Then,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during calibration.Furthermore,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate system.Finally,the accuracy of the calibration method is verified through simulation experiments and calibration tests.This method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool measurements.This research significantly improves the efficient production performance of smart machine tools.展开更多
The changes in land use in the last 30 years in the territory of agro-forest watershed of Lake Buyo resulted in significant sediment into the lake. Sediments are a preferred means of transportation for certain polluta...The changes in land use in the last 30 years in the territory of agro-forest watershed of Lake Buyo resulted in significant sediment into the lake. Sediments are a preferred means of transportation for certain pollutants, like phosphorus in excess. By mapping the source areas of erosion, the authors can determine the risk areas and help to prioritize interventions in the territory. This mapping is done using the SWAT （soil and water assessment tool） model. Several types of data, including topography, land use, soil and climate data are needed to run the model. In this paper, all different steps are presented, from the designing of HRU （hydrological response units）, basic units to run the SWAT model until the simulations. The establishment of HRU has three main stages： space discretization, land use and soil data integration and HRU distribution： （1） space discretization which consist in extracting the limits and the water network of the watershed from the DEM （digital elevation model） and in subdividing them into sub-basins; （2） land use and soil data integration： it consists in digitizing the physical maps of land use and of soils under Mapinfo 7.5 and in keeping them in ＂shape＂ format; （3） HRU distribution： it leads to subdivide the sub-watersheds in small units that combine a single soil type and one type of land use. It appears from this study to obtain 23 sub-watersheds and 71 HRU. Once the HRU designed, it is necessary to integrate climate data, data on physico-chemical characteristics of soils and agricultural practices, before starting the simulations. This will allow the model to assess the risk of sedimentation and eutrophication of the lake using the MUSLE （modified universal soil loss equation） and phosphorus cycle.展开更多
The Lobo watershed is an agricultural area where the use of fertilizers by farmers is intensive, causing eutrophication problems that deteriorate the quality of drinking water distributed to the population. Since the ...The Lobo watershed is an agricultural area where the use of fertilizers by farmers is intensive, causing eutrophication problems that deteriorate the quality of drinking water distributed to the population. Since the phenomenon of eutrophication is directly linked to runoff, it is essential to model the flow in order to better control the transfer of nutrients responsible for eutrophication. It is within this framework that this study was conducted. The objective of this study is to assess the ability of the semi-distributed SWAT (Soil and Water Assessment Tool) model to simulate runoff in the Lobo watershed. The methodology adopted was based on the use of the QSWAT graphical interface to manipulate and execute the main functions of the SWAT model from QGIS tools. The hydrological modeling was carried out with the QSWAT interface for SWAT 2012. The results showed good performance for the flow calibration (1982-1984) with the evaluation criteria R<sup>2</sup>, NSE and PBIAS respectively of 0.64, 0.64 and 3.1. In the validation period (1984-1987), the model also showed good performance in the streamflow simulation for R<sup>2</sup> and NSE of 0.84 and 0.76 respectively as values. However, for the PBAIS criterion, the result was less good but still remains satisfactory with a value of 19.6. It emerges from this study that the SWAT model is suitable for simulating water transfer and can therefore be used to study the transfer of pollutants in the fight against eutrophication in the Lobo watershed.展开更多
针对高寒脆弱河流水环境容量受水文-生物地球化学耦合过程制约,缺乏量化研究的问题,以洮河部分河段为研究对象,基于SWAT(Soil and Water Assessment Tool)模型模拟流域径流特征,结合WASP(Water Analysis Simulation Program)模型分析河...针对高寒脆弱河流水环境容量受水文-生物地球化学耦合过程制约,缺乏量化研究的问题,以洮河部分河段为研究对象,基于SWAT(Soil and Water Assessment Tool)模型模拟流域径流特征,结合WASP(Water Analysis Simulation Program)模型分析河流水环境指标构建SWAT-WASP耦合水质模型,建立水环境容量定量计算框架,定量评估青藏高原东北缘高寒流域水环境容量时空分布特征.模型模拟结果与实测数据具有良好的一致性,在水流量、径流深等方面相关系数均达到0.6以上;Ⅰ类水质标准下BOD、TP和DO的年水环境容量分别为157.6、2.067和221.8t,而TN需放宽至Ⅳ类标准,年水环境容量为50.38t;对于BOD、TP和DO的水环境容量,空间维度显示上游为下游的9.9%~10.3%,时间维度显示1月(枯水期)为7月(丰水期)的10.1%~34.2%,分别凸显了高寒脆弱流域水动力条件和季节性水文驱动的主导作用,明确高寒脆弱流域可持续发展阈值;以TN为优先管控限制因子,提出时空协同分配策略,为高寒脆弱型水源区适应性水质管理提供科学依据.展开更多
基金supported by the National Natural Science Foundation of China(Nos.41975044,42371354,41801021,42101385)Open Fund of Hubei Luojia Laboratory(No.2201000043)the Fundamental Research Funds for National Universities,China University of Geosciences,Wuhan。
文摘As a crucial human activity,dam construction can profoundly impact the surface hydrology patterns.The Three Gorges Reservoir(TGR),as one of the largest hydraulic engineering projects in the world,has gained continuous attention for its eco-hydrological effects.However,further investigation is necessary to understand the runoff and social impacts of the TGR on the Upper Yangtze River.This study first employed a modified SWAT model to simulate runoff,compared scenarios with and without the TGR,and finally evaluated water supply and demand in the Upper Yangtze River.The results showed a significant increasing trend in the surface water area of the Upper Yangtze River from 2000-2020.The modified SWAT model performs well in simulating the runoff,with Nash-Sutcliffe Efficiency and Percent Bias improved by 0.04-0.30 and 2-31.90,respectively.Scenario simulation results revealed that the TGR reduced seasonal differences in runoff.During the flood season,the runoff volume at the Yichang Station in the scenario with the TGR is lower than in the scenario without the TGR,peaking at 4500 m3/s.Conversely,in the dry season,the runoff volume of the scenario with TGR is higher,with a maximum increase of 1500 m3/s.The region exhibiting the greatest runoff variations is the Yangtze River's main stem in the Three Gorges Reservoir region.Besides,the TGR notably alleviated the water supply-demand imbalance in Chongqing during the winter and spring seasons,with a maximum increase of 0.16 in the supplydemand index.This study can contribute significantly to understanding the natural and social impacts of the TGR from the perspective of hydrological and scenario simulation.
基金supported by the National Natural Science Foundation of China(Grant No.52075255)the Jiangsu Provincial Science and Technology Plan(Grant No.BZ2023005).
文摘High-volume fraction silicon particle-reinforced aluminium matrix composites(Si/Al)are increasingly applied in aerospace,radar communications,and large-scale integrated circuits because of their superior thermal conductivity,wear resistance,and low thermal expansion coefficient.However,the abrasive and adhesive wear caused by the hard silicon reinforcement and the ductile aluminium matrix leads to significant tool wear,decreased machining efficiency,and compromised surface quality.This study combines theoretical analysis and cutting experiments to investigate polycrystalline diamond(PCD)tool wear during milling of 70 vol%Si/Al composite.A key contribution of this work is the development of a tool wear model that incorporates reinforcement particle characteristics,treating them as ellipsoidal structures,which enhances the accuracy of predicting abrasive and adhesive wear mechanisms.The model is based on abrasive and adhesive wear mechanisms,and can analyze the interaction between silicon particles,aluminium matrix,and tool components,thus providing deeper insights into PCD tool wear processes.Experimental validation of the model shows a good agreement with the results,with a mean deviation of approximately 10%.The findings on the tool wear mechanism reveal that,as tool wear progresses,the proportion of abrasive wear increases from 40%in the running-in stage to 75%in the rapid wear stage,while adhesive wear decreases.The optimal machining parameters of 120 m·min^(–1) cutting speed(v_(c))and 0.04 mm·z^(–1) feed rate(f_(z)),result in tool life of 33 min and surface roughness(S_(a))of 2.2μm.The study uncovers the variation patterns of abrasive and adhesive wear during the tool wear process,and the proposed model offers a robust framework for predicting tool wear during the machining of high-volume fraction Si/Al composites.The research findings also offer key insights for optimizing tool selection and machining parameters,advancing both the theoretical understanding and practical application of PCD tool wear.
基金co-supported the National Natural Science Foundation of China(No.52235010)the Heilongjiang Postdoctoral Fund(No.LBH-Z22136)the New Era Longjiang Excellent Master and Doctoral Dissertation Fund(No.LJYXL2022-057).
文摘To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’along the spiral trajectory,was proposed.From the kinematics analysis,it is found that the machining quality of micro-dimpled structures is highly dependent on the machining trajectory using spiral trajectory tool reciprocating motion.To reveal this causation,simulation modelling and experimental studies were carried out.A simulation model was developed to quantitatively and qualitatively investigate the influence of the trajectory discretization strategies(constant-angle and constant-arc length)and parameters(discrete angle,discrete arc length,and pitch)on surface texture and residual height of micro-dimpled structures.Subsequently,micro-dimpled structures were milled under different trajectory discretization strategies and parameters with spiral trajectory tool reciprocating motion.A comprehensive comparison between the milled results and simulation analysis was made based on geometry accuracy,surface morphology and surface roughness of milled dimples.Meanwhile,the errors and factors affecting the above three aspects were analyzed.The results demonstrate both the feasibility of the established simulation model and the machining capability of this machining way in milling high-quality micro-dimpled structures.Spiral trajectory tool reciprocating motion provides a new machining way for milling micro-dimpled structures and micro-dimpled functional surfaces.And an appropriate machining trajectory can be generated based on the optimized trajectory parameters,thus contributing to the improvement of machining quality and efficiency.
文摘This article evaluates the transformative potential of large language models(LLMs)as patient education tools for managing inflammatory bowel disease.The discussion highlights their ability to deliver nuanced and personalized infor-mation,addressing limitations in traditional educational materials.Key consider-ations include the necessity for domain-specific fine-tuning to enhance accuracy,the adoption of robust evaluation metrics beyond readability,and the integration of LLMs with clinical decision support systems to improve real-time patient education.Ethical and accessibility challenges,such as algorithmic bias,data privacy,and digital literacy,are also examined.Recommendations emphasize the importance of interdisciplinary collaboration to optimize LLM integration,en-suring equitable access and improved patient outcomes.By advancing LLM technology,healthcare can empower patients with accurate and personalized information,enhancing engagement and disease management.
文摘Modelling the hydrological balance in semi-arid zones is essential for effective water resource management,encompassing both surface water and groundwater.This study aims to model the monthly hydrological water cycle in the Wadi Mina upstream watershed(northwest Algeria)by applying the Soil and Water Assessment Tool(SWAT)hydrological model.SWAT modelling integrates spatial data such as the Digital Elevation Model(DEM),land use,soil types and various meteorological parameters including precipitation,maximum and minimum temperatures,relative humidity,solar radiation and wind speed.The SWAT model was calibrated and validated using data from January 2012 to December 2014,with a calibra-tion period from January 2012 to August 2013 and a validation period from September 2013 to December 2014.Sensitivity and parameter calibration were conducted using the SWAT-SA program,and model performance evaluation relied on comparing the observed discharge at the outlet of the basin with model-simulated discharge,assessed through statistical coefficients including Nash-Sutcliffe Efficiency(NSE),coefficient of determination(R2)and Percent Bias(PBAIS).Calibration results indicated favourable objec-tive function values(NSE=0.79,R2=0.93,PBAIS=-8.53%),although a slight decrease was observed during validation(NSE=0.69,R2=0.86,and PBAIS=-11.41%).The application of the SWAT model to the Wadi Mina upstream watershed highlighted its utility in simulating the spatial distribution of different components of the hydrological balance in this basin.The SWAT model revealed that approximately 71%of the precipitation in the basin evaporates,while only 29%contributes to surface runoff or infiltration into the soil.
基金supported by the National Natural Science Foundation of China(Nos.52005413,52022082)Natural Science Basic Research Plan in Shaanxi Province of China(No.2021JM-054)the Fundamental Research Funds for the Central Universities(No.D5000220135)。
文摘Geometric error,mainly due to imperfect geometry and dimensions of machine components,is one of the major error sources of machine tools.Considering that geometric error has significant effects on the machining quality of manufactured parts,it has been a popular topic for academic and industrial research for many years.A great deal of research work has been carried out since the 1970s for solving the problem and improving the machining accuracy.Researchers have studied how to measure,detect,model,identify,reduce,and compensate the geometric errors.This paper presents a thorough review of the latest research activities and gives an overview of the state of the art in understanding changes in machine tool performance due to geometric errors.Recent advances in measuring the geometrical errors of machine tools are summarized,and different kinds of error identification methods of translational axes and rotation axes are illustrated respectively.Besides,volumetric geometric error modeling,tracing,and compensation techniques for five-axis machine tools are emphatically introduced.Finally,research challenges in order to improve the volumetric accuracy of machine tools are also highlighted.
文摘Hydrological modeling plays a crucial role in efficiently managing water resources and understanding the hydrologic behavior of watersheds. This study aims to simulate daily streamflow in the Godavari River Basin in Maharashtra using the Soil and Water Assessment Tool (SWAT). SWAT is a process-based hydrological model used to predict water balance components, sediment levels, and nutrient contamination. In this research, we used integrated remote sensing and GIS data, including Digital Elevation Models (DEM), land use and land cover (LULC) maps, soil maps, and observed precipitation and temperature data, as input for developing the SWAT model to assess surface runoff in this large river basin. The Godavari River Basin under study was divided into 25 sub-basins, comprising 151 hydrological response units categorized by unique land cover, soil, and slope characteristics using the SWAT model. The model was calibrated and validated against observed runoff data for two time periods: 2003-2006 and 2007-2010 respectively. Model performance was assessed using the Nash-Sutcliffe efficiency (NSE) and the coefficient of determination (R2). The results show the effectiveness of the SWAT2012 model, with R2 value of 0.84 during calibration and 0.86 during validation. NSE values also ranged from 0.84 during calibration to 0.85 during validation. These findings enhance our understanding of surface runoff dynamics in the Godavari River Basin under study and highlight the suit-ability of the SWAT model for this region.
文摘On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine tools.Laser tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and diameter.As a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before use.However,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring rod.To address this issue,this study proposes a novel calibration method.Initially,the calibration mechanism of the laser beam axis is established.Based on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is established.Then,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during calibration.Furthermore,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate system.Finally,the accuracy of the calibration method is verified through simulation experiments and calibration tests.This method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool measurements.This research significantly improves the efficient production performance of smart machine tools.
文摘The changes in land use in the last 30 years in the territory of agro-forest watershed of Lake Buyo resulted in significant sediment into the lake. Sediments are a preferred means of transportation for certain pollutants, like phosphorus in excess. By mapping the source areas of erosion, the authors can determine the risk areas and help to prioritize interventions in the territory. This mapping is done using the SWAT （soil and water assessment tool） model. Several types of data, including topography, land use, soil and climate data are needed to run the model. In this paper, all different steps are presented, from the designing of HRU （hydrological response units）, basic units to run the SWAT model until the simulations. The establishment of HRU has three main stages： space discretization, land use and soil data integration and HRU distribution： （1） space discretization which consist in extracting the limits and the water network of the watershed from the DEM （digital elevation model） and in subdividing them into sub-basins; （2） land use and soil data integration： it consists in digitizing the physical maps of land use and of soils under Mapinfo 7.5 and in keeping them in ＂shape＂ format; （3） HRU distribution： it leads to subdivide the sub-watersheds in small units that combine a single soil type and one type of land use. It appears from this study to obtain 23 sub-watersheds and 71 HRU. Once the HRU designed, it is necessary to integrate climate data, data on physico-chemical characteristics of soils and agricultural practices, before starting the simulations. This will allow the model to assess the risk of sedimentation and eutrophication of the lake using the MUSLE （modified universal soil loss equation） and phosphorus cycle.
文摘The Lobo watershed is an agricultural area where the use of fertilizers by farmers is intensive, causing eutrophication problems that deteriorate the quality of drinking water distributed to the population. Since the phenomenon of eutrophication is directly linked to runoff, it is essential to model the flow in order to better control the transfer of nutrients responsible for eutrophication. It is within this framework that this study was conducted. The objective of this study is to assess the ability of the semi-distributed SWAT (Soil and Water Assessment Tool) model to simulate runoff in the Lobo watershed. The methodology adopted was based on the use of the QSWAT graphical interface to manipulate and execute the main functions of the SWAT model from QGIS tools. The hydrological modeling was carried out with the QSWAT interface for SWAT 2012. The results showed good performance for the flow calibration (1982-1984) with the evaluation criteria R<sup>2</sup>, NSE and PBIAS respectively of 0.64, 0.64 and 3.1. In the validation period (1984-1987), the model also showed good performance in the streamflow simulation for R<sup>2</sup> and NSE of 0.84 and 0.76 respectively as values. However, for the PBAIS criterion, the result was less good but still remains satisfactory with a value of 19.6. It emerges from this study that the SWAT model is suitable for simulating water transfer and can therefore be used to study the transfer of pollutants in the fight against eutrophication in the Lobo watershed.
文摘针对高寒脆弱河流水环境容量受水文-生物地球化学耦合过程制约,缺乏量化研究的问题,以洮河部分河段为研究对象,基于SWAT(Soil and Water Assessment Tool)模型模拟流域径流特征,结合WASP(Water Analysis Simulation Program)模型分析河流水环境指标构建SWAT-WASP耦合水质模型,建立水环境容量定量计算框架,定量评估青藏高原东北缘高寒流域水环境容量时空分布特征.模型模拟结果与实测数据具有良好的一致性,在水流量、径流深等方面相关系数均达到0.6以上;Ⅰ类水质标准下BOD、TP和DO的年水环境容量分别为157.6、2.067和221.8t,而TN需放宽至Ⅳ类标准,年水环境容量为50.38t;对于BOD、TP和DO的水环境容量,空间维度显示上游为下游的9.9%~10.3%,时间维度显示1月(枯水期)为7月(丰水期)的10.1%~34.2%,分别凸显了高寒脆弱流域水动力条件和季节性水文驱动的主导作用,明确高寒脆弱流域可持续发展阈值;以TN为优先管控限制因子,提出时空协同分配策略,为高寒脆弱型水源区适应性水质管理提供科学依据.
