Texture and grain structure evolution during annealing and their effects on tensile strength and anisotropy were studied using XRD,DSC,SEM,EBSD and TEM.The results indicate that elevated rolling temperatures reduce th...Texture and grain structure evolution during annealing and their effects on tensile strength and anisotropy were studied using XRD,DSC,SEM,EBSD and TEM.The results indicate that elevated rolling temperatures reduce the f(g)_(max(Copper))/f(g)_(max(Brass))ratio,increase S-Brass fine bands,and promote S-dispersoid precipitation,leading to finer recrystallized grains.Dominant recrystallization textures transform from Goss+P to Goss and then to Goss+Cube with increasing rolling temperature.Annealing at 350℃shows four tensile strength response stages:fast softening I,rapid strengthening II,slow strengthening III,and slow softening IV.The transition from Stages I to II is driven by the formation of strong Goss and P textures,and Stage IV is linked to enhanced Cube texture.Plates with Goss+Cube textures and fine equiaxed grains exhibit the lowest YS/UTS ratio and minimal anisotropy.展开更多
目的探究MR 3D CUBE与常规磁共振成像(MRI)在膝关节前交叉韧带损伤中的应用价值。方法选取2022年1月至2024年4月本院收治的136例膝关节前交叉韧带损伤患者,根据患者损伤程度分为Ⅰ级、Ⅱ级和Ⅲ级;患者均进行MR 3D CUBE与常规MRI检查;Ka...目的探究MR 3D CUBE与常规磁共振成像(MRI)在膝关节前交叉韧带损伤中的应用价值。方法选取2022年1月至2024年4月本院收治的136例膝关节前交叉韧带损伤患者,根据患者损伤程度分为Ⅰ级、Ⅱ级和Ⅲ级;患者均进行MR 3D CUBE与常规MRI检查;Kappa检验分析MR 3D CUBE、常规MRI与关节镜诊断的一致性;以关节镜检查结果为金标准,采用四格表分析MR 3D CUBE与常规MRI对膝关节前交叉韧带不同损伤分级的诊断价值;膝关节前交叉韧带损伤治疗效果的影响因素采用Logistic回归分析。结果MR 3D CUBE、常规MRI与关节镜诊断的一致性较好(Kappa=0.664、0.832,P<0.05)。MR 3D CUBE在诊断膝关节前交叉韧带损伤Ⅰ级时准确度为91.91%,Ⅱ级时准确度为91.18%,Ⅲ级时准确度为94.85%;常规MRI在诊断膝关节前交叉韧带损伤Ⅰ级时准确度为85.29%,Ⅱ级时准确度为83.09%,Ⅲ级时准确度为87.50%,MR 3D CUBE在诊断膝关节前交叉韧带损伤Ⅲ级时准确度显著高于常规MRI(P<0.05)。不良组和良好组病程和既往损伤比较有差异(P<0.05)。多因素Logistic回归分析得知,病程和既往损伤是影响膝关节前交叉韧带损伤患者治疗效果的危险因素(P<0.05)。结论MR 3D CUBE与常规MRI均能诊断膝关节前交叉韧带损伤,但MR 3D CUBE诊断效能高于常规MRI,可在临床应用。展开更多
Key technologies that make productivity increase are revealed through analyzing the best practices and production data in major shale basins of North America.Trends of the key technologies and optimization designs for...Key technologies that make productivity increase are revealed through analyzing the best practices and production data in major shale basins of North America.Trends of the key technologies and optimization designs for shale oil and gas development are summarized and analyzed based on drilling and completion operations and well data.These technologies mainly include:(1)Optimizing well design and hydraulic fracturing design,including reducing cluster spacing,increasing proppant and fracturing fluid volumes,optimizing horizontal well lateral length and fracture stage length.The most effective method is to reduce cluster spacing to an optimized length.The second most effective method is to optimally increase proppant volumes.(2)Placing horizontal wells in the sweet spots and drilling the wells parallel or close to the minimum horizontal stress direction.(3)Using cube development with optimized well spacing to maximize resource recovery and reduce well interferences.Plus,in-situ stress impacts on hydraulic fracture propagation and hydrocarbon production are addressed.Determination of formation breakdown pressure is studied by considering the impacts of in-situ stresses,drilling and perforation directions.Whether or not the hydraulic fracturing can generate orthogonal fracture networks is also discussed.The key technologies and optimization design parameters proposed in this paper can be applied to guide new well placement,drilling and completion designs,and hydraulic fracture operations to increase productivity.展开更多
Infrastructure construction in seasonally frozen regions,covering 23%of total land,faces challenges from freeze-thaw(F-T)induced damages.Expansive soils,as an important problematic soil undergo major hydromechanical p...Infrastructure construction in seasonally frozen regions,covering 23%of total land,faces challenges from freeze-thaw(F-T)induced damages.Expansive soils,as an important problematic soil undergo major hydromechanical properties changes influenced by F-T cycles.Sand-bentonite mixtures are extensively used for constructing earthen hydraulic barriers in cold regions.This study investigates the influence of F-T cycles on multi-directional strains and anisotropic hydraulic conductivity of different sand-bentonite mixtures prepared at optimum water content and experienced three distinct saturation levels.Results indicate that saturation level and bentonite content significantly influence volumetric strain under F-T cycles.The simultaneous effect of ice lens formation,expanding micro-voids,and suction generated by freezing processes cause different volumetric behaviors at varying saturation degrees.The dry specimen exhibits no strain under F-T cycles,while optimum and saturated specimens experienced final volumetric strains of 1.02%and 3.03%,respectively.Notably,during freezing,the specimen at optimumwater content shrank,while the saturated specimen expanded.Increasing bentonite content from 40%to 70%developed freezing-induced shrinkage,from 1.73%to 4.72%,with higher thaw strain attributed to increased specimen plasticity.Also,dimensional variations revealed the cross-anisotropic nature of specimens,highlighting direct influence of water content on the shrinkage ratio.F-T cycles also increased hydraulic conductivity along both orthogonal directions by two orders of magnitude,while the anisotropy ratio decreased by about 3 after 9 F-T cycles,indicating altered pore structures.F-T cycles induce reduced swelling potential and compressibility over subsequent cycles.Microstructural observations also confirmed the F-T effects on the enhancement of porosity.展开更多
This study seeks to establish a novel,semi-automatic system that utilizes Industry 4.0 principles to effectively determine both acceptable and rejectable concrete cubes with regard to their failure modes,significantly...This study seeks to establish a novel,semi-automatic system that utilizes Industry 4.0 principles to effectively determine both acceptable and rejectable concrete cubes with regard to their failure modes,significantly contributing to the dependability of concrete quality evaluations.The study utilizes image processing and machine learning(ML)methods,namely object detectionmodels such as YOLOv8 and Convolutional Neural Networks(CNNs),to evaluate images of concrete cubes.These models are trained and validated on an extensive database of annotated images from real-world and laboratory conditions.Preliminary results indicate a good performance in the classification of concrete cube failure modes.The proposed system accurately identifies cracks,determines the severity of damage to structures,indicating the potential to minimize human errors and discrepancies that might occur through the current techniques to detect the failure mode of concrete cubes.Thedeveloped systemcould significantly improve the reliability of concrete cube assessments,reduce resource wastage,and contribute to more sustainable construction practices.By minimizing material costs and errors,this innovation supports the construction industry’s move towards sustainability.展开更多
The method for optimizing the hydraulic fracturing parameters of the cube development infill well pad was proposed,aiming at the well pattern characteristic of“multi-layer and multi-period”of the infill wells in Sic...The method for optimizing the hydraulic fracturing parameters of the cube development infill well pad was proposed,aiming at the well pattern characteristic of“multi-layer and multi-period”of the infill wells in Sichuan Basin.The fracture propagation and inter-well interference model were established based on the evolution of 4D in-situ stress,and the evolution characteristics of stress and the mechanism of interference between wells were analyzed.The research shows that the increase in horizontal stress difference and the existence of natural fractures/faults are the main reasons for inter-well interference.Inter-well interference is likely to occur near the fracture zones and between the infill wells and parent wells that have been in production for a long time.When communication channels are formed between the infill wells and parent wells,it can increase the productivity of parent wells in the short term.However,it will have a delayed negative impact on the long-term sustained production of both infill wells and parent wells.The change trend of in-situ stress caused by parent well production is basically consistent with the decline trend of pore pressure.The lateral disturbance range of in-situ stress is initially the same as the fracture length and reaches 1.5 to 1.6 times that length after 2.5 years.The key to avoiding inter-well interference is to optimize the fracturing parameters.By adopting the M-shaped well pattern,the optimal well spacing for the infill wells is 300 m,the cluster spacing is 10 m,and the liquid volume per stage is 1800 m^(3).展开更多
基金financial support from the National Key Research and Development Program of China(No.2016YFB0300900)the National Key Fundamental Research Project of China(No.2012CB619506-3)the National Natural Science Foundation of China(No.51171209)。
文摘Texture and grain structure evolution during annealing and their effects on tensile strength and anisotropy were studied using XRD,DSC,SEM,EBSD and TEM.The results indicate that elevated rolling temperatures reduce the f(g)_(max(Copper))/f(g)_(max(Brass))ratio,increase S-Brass fine bands,and promote S-dispersoid precipitation,leading to finer recrystallized grains.Dominant recrystallization textures transform from Goss+P to Goss and then to Goss+Cube with increasing rolling temperature.Annealing at 350℃shows four tensile strength response stages:fast softening I,rapid strengthening II,slow strengthening III,and slow softening IV.The transition from Stages I to II is driven by the formation of strong Goss and P textures,and Stage IV is linked to enhanced Cube texture.Plates with Goss+Cube textures and fine equiaxed grains exhibit the lowest YS/UTS ratio and minimal anisotropy.
文摘目的探究MR 3D CUBE与常规磁共振成像(MRI)在膝关节前交叉韧带损伤中的应用价值。方法选取2022年1月至2024年4月本院收治的136例膝关节前交叉韧带损伤患者,根据患者损伤程度分为Ⅰ级、Ⅱ级和Ⅲ级;患者均进行MR 3D CUBE与常规MRI检查;Kappa检验分析MR 3D CUBE、常规MRI与关节镜诊断的一致性;以关节镜检查结果为金标准,采用四格表分析MR 3D CUBE与常规MRI对膝关节前交叉韧带不同损伤分级的诊断价值;膝关节前交叉韧带损伤治疗效果的影响因素采用Logistic回归分析。结果MR 3D CUBE、常规MRI与关节镜诊断的一致性较好(Kappa=0.664、0.832,P<0.05)。MR 3D CUBE在诊断膝关节前交叉韧带损伤Ⅰ级时准确度为91.91%,Ⅱ级时准确度为91.18%,Ⅲ级时准确度为94.85%;常规MRI在诊断膝关节前交叉韧带损伤Ⅰ级时准确度为85.29%,Ⅱ级时准确度为83.09%,Ⅲ级时准确度为87.50%,MR 3D CUBE在诊断膝关节前交叉韧带损伤Ⅲ级时准确度显著高于常规MRI(P<0.05)。不良组和良好组病程和既往损伤比较有差异(P<0.05)。多因素Logistic回归分析得知,病程和既往损伤是影响膝关节前交叉韧带损伤患者治疗效果的危险因素(P<0.05)。结论MR 3D CUBE与常规MRI均能诊断膝关节前交叉韧带损伤,但MR 3D CUBE诊断效能高于常规MRI,可在临床应用。
文摘Key technologies that make productivity increase are revealed through analyzing the best practices and production data in major shale basins of North America.Trends of the key technologies and optimization designs for shale oil and gas development are summarized and analyzed based on drilling and completion operations and well data.These technologies mainly include:(1)Optimizing well design and hydraulic fracturing design,including reducing cluster spacing,increasing proppant and fracturing fluid volumes,optimizing horizontal well lateral length and fracture stage length.The most effective method is to reduce cluster spacing to an optimized length.The second most effective method is to optimally increase proppant volumes.(2)Placing horizontal wells in the sweet spots and drilling the wells parallel or close to the minimum horizontal stress direction.(3)Using cube development with optimized well spacing to maximize resource recovery and reduce well interferences.Plus,in-situ stress impacts on hydraulic fracture propagation and hydrocarbon production are addressed.Determination of formation breakdown pressure is studied by considering the impacts of in-situ stresses,drilling and perforation directions.Whether or not the hydraulic fracturing can generate orthogonal fracture networks is also discussed.The key technologies and optimization design parameters proposed in this paper can be applied to guide new well placement,drilling and completion designs,and hydraulic fracture operations to increase productivity.
基金The financial support provided by the Research Grant Office at Sharif University Technology(Grant Nos.G4010902 and QB020105)is gratefully acknowledged.
文摘Infrastructure construction in seasonally frozen regions,covering 23%of total land,faces challenges from freeze-thaw(F-T)induced damages.Expansive soils,as an important problematic soil undergo major hydromechanical properties changes influenced by F-T cycles.Sand-bentonite mixtures are extensively used for constructing earthen hydraulic barriers in cold regions.This study investigates the influence of F-T cycles on multi-directional strains and anisotropic hydraulic conductivity of different sand-bentonite mixtures prepared at optimum water content and experienced three distinct saturation levels.Results indicate that saturation level and bentonite content significantly influence volumetric strain under F-T cycles.The simultaneous effect of ice lens formation,expanding micro-voids,and suction generated by freezing processes cause different volumetric behaviors at varying saturation degrees.The dry specimen exhibits no strain under F-T cycles,while optimum and saturated specimens experienced final volumetric strains of 1.02%and 3.03%,respectively.Notably,during freezing,the specimen at optimumwater content shrank,while the saturated specimen expanded.Increasing bentonite content from 40%to 70%developed freezing-induced shrinkage,from 1.73%to 4.72%,with higher thaw strain attributed to increased specimen plasticity.Also,dimensional variations revealed the cross-anisotropic nature of specimens,highlighting direct influence of water content on the shrinkage ratio.F-T cycles also increased hydraulic conductivity along both orthogonal directions by two orders of magnitude,while the anisotropy ratio decreased by about 3 after 9 F-T cycles,indicating altered pore structures.F-T cycles induce reduced swelling potential and compressibility over subsequent cycles.Microstructural observations also confirmed the F-T effects on the enhancement of porosity.
文摘This study seeks to establish a novel,semi-automatic system that utilizes Industry 4.0 principles to effectively determine both acceptable and rejectable concrete cubes with regard to their failure modes,significantly contributing to the dependability of concrete quality evaluations.The study utilizes image processing and machine learning(ML)methods,namely object detectionmodels such as YOLOv8 and Convolutional Neural Networks(CNNs),to evaluate images of concrete cubes.These models are trained and validated on an extensive database of annotated images from real-world and laboratory conditions.Preliminary results indicate a good performance in the classification of concrete cube failure modes.The proposed system accurately identifies cracks,determines the severity of damage to structures,indicating the potential to minimize human errors and discrepancies that might occur through the current techniques to detect the failure mode of concrete cubes.Thedeveloped systemcould significantly improve the reliability of concrete cube assessments,reduce resource wastage,and contribute to more sustainable construction practices.By minimizing material costs and errors,this innovation supports the construction industry’s move towards sustainability.
基金Supported by the General Program of the NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA(52374004)National Key Research and Development Program(2023YFF06141022023YFE0110900)。
文摘The method for optimizing the hydraulic fracturing parameters of the cube development infill well pad was proposed,aiming at the well pattern characteristic of“multi-layer and multi-period”of the infill wells in Sichuan Basin.The fracture propagation and inter-well interference model were established based on the evolution of 4D in-situ stress,and the evolution characteristics of stress and the mechanism of interference between wells were analyzed.The research shows that the increase in horizontal stress difference and the existence of natural fractures/faults are the main reasons for inter-well interference.Inter-well interference is likely to occur near the fracture zones and between the infill wells and parent wells that have been in production for a long time.When communication channels are formed between the infill wells and parent wells,it can increase the productivity of parent wells in the short term.However,it will have a delayed negative impact on the long-term sustained production of both infill wells and parent wells.The change trend of in-situ stress caused by parent well production is basically consistent with the decline trend of pore pressure.The lateral disturbance range of in-situ stress is initially the same as the fracture length and reaches 1.5 to 1.6 times that length after 2.5 years.The key to avoiding inter-well interference is to optimize the fracturing parameters.By adopting the M-shaped well pattern,the optimal well spacing for the infill wells is 300 m,the cluster spacing is 10 m,and the liquid volume per stage is 1800 m^(3).
