There has been lack of work efforts on how to optimize cementing and completing parameters in order to prevent casing failure induced by formation slippage in pertroleum industry scope.Once the weak plane fails,the fo...There has been lack of work efforts on how to optimize cementing and completing parameters in order to prevent casing failure induced by formation slippage in pertroleum industry scope.Once the weak plane fails,the formation will become easily undertaken slippage across a large area along its interface.The plenty of horizontal planes of weakness in reservoir formations,as reported for a number of oilfields,can easily undertaken slippage once it fails.To address the problem,three-dimensional finite element models were established by taking into considerations the elastoplastic mechanical characteristics of both the casing and the near-wellbore rock.Two types of casing impairment scenarios were considered:Casing collapse(that causes tubing stuck in the well)and complete casing shear-off.In this study,the critical slip displacement of casing shear damage under both cemented and un-cemented conditions was calculated,and the critical displacement of casing with various wall thicknesses and steel grades was compared.A new cementing practice for the Daqing oilfield was then proposed by optimizing casing parameters according to API standards,and a new research method was also put forward by proposing new casing materials to effectively mitigate casing failure caused by formation slippage for the future.Modeling results indicate that the stress and deformation associated with casing in the un-cemented condition is more diffused and the critical slippage displacement is larger than that in the cemented condition.Therefore,the un-cemented condition is more effective in preventing casing shear failure and easier for casing repair,for the case of casing damage caused by formation shear slippage.Casing elongation is the key parameter of casing shear failure in the un-cemented condition.Lower grade casing exhibits a larger critical slippage displacement because of its higher elongation capacity under stress.Casing with lower grade and smaller thickness provides more advantages in preventing casing damage in formations abundant with horizontal weak layers.If the elongation of casing can be largely improved,the critical displacement value can be increased by 21.40%.Higher grade and thicker casing is adapted for mitigate casing failure caused by formation slippage.展开更多
The jacket structure and transition piece comprise the supporting structure of a bottom-fixed offshore wind turbine(OWT)connected to the steel tower,which determines the overall structural dynamic performance of the e...The jacket structure and transition piece comprise the supporting structure of a bottom-fixed offshore wind turbine(OWT)connected to the steel tower,which determines the overall structural dynamic performance of the entire OWT.Ideally,optimal performance can be realized by effectively coordinating two components,notwithstanding their separate design processes.In pursuit of this objective,this paper proposes a concurrent design methodology for the jacket structure and transition piece by exploiting topology optimization(TO).The TO for a three-legged jacket foundation is formulated by minimizing static compliance.In contrast to conventional TO,two separated volume fractions are imposed upon the structural design domain of the jacket structure and transition piece to ensure continuity.A 5 MW(megawatt)OWT supported by a four-legged or three-legged jacket substructure is under investigation.The external loads are derived from various design load cases that are acquired using the commercial software platform DNV Bladed(Det Norske Veritas).Through a comparative analysis of the fundamental frequency and maximum nodal deformation,it was found that the optimized solution demonstrates a reduced weight and superior stiffness.The findings demonstrate the present concurrent design approach using TO can yield significant benefits by reducing the overall design cycle and enhancing the feasibility of the final design.展开更多
The traditional teaching methods of one-way cultivation of students can no longer meet the requirements of talent cultivation at this stage.The issue of how to promote students from passive acceptance to the independe...The traditional teaching methods of one-way cultivation of students can no longer meet the requirements of talent cultivation at this stage.The issue of how to promote students from passive acceptance to the independent cognitive understanding stage(i.e.deep learning)has become the focus of geography teaching.Therefore,under the guidance of deep learning theory,this paper takes the“landforms”knowledge unit of the Humanistic Education Edition as an example,improves the classroom teaching means through the unit teaching mode,reconstructs the“landforms”teaching unit,and explores the specific teaching of high school geography unit based on deep learning.This study provides a good example and guidelines for high school geography teaching and learning.展开更多
Curriculum ideology and politics is the key to carry out the mission of educating people in colleges and universities in the new era.On the problem of integrating the linear algebra course into the ideological and pol...Curriculum ideology and politics is the key to carry out the mission of educating people in colleges and universities in the new era.On the problem of integrating the linear algebra course into the ideological and political education,it was expounded from four aspects:the necessity of integrating the course ideology and politics into the teaching of linear algebra,exploring curriculum ideological and political elements,the case design of integrating the course ideology and politics teaching,and the expected effect of integrating linear algebra courses into ideological and political education in the curriculum,in order to have the reference and help function to the educator.展开更多
In higher engineering education,professional courses and ideological and political theory courses go in the same direction,which is an important task of the current professional curriculum construction.This paper intr...In higher engineering education,professional courses and ideological and political theory courses go in the same direction,which is an important task of the current professional curriculum construction.This paper introduces the key and difficult problems in the teaching content of the course Engineering Valuation in the Department of Engineering Management and Real Estate of Jiangxi Normal University.Based on the characteristics of simulation information technology such as BIM and VR and the differences of ideological and political elements,it updates and improves the cases of courses for ideological and political education,gives full play to the synergistic effect,and realizes the"triple"talent training goal of knowledge,ability and literacy.展开更多
Since the idea of“Curriculum-Based Ideological and Political Education”was formally proposed in 2016,it has rapidly become a research hotspot in education reform.Although a large number of relevant studies have focu...Since the idea of“Curriculum-Based Ideological and Political Education”was formally proposed in 2016,it has rapidly become a research hotspot in education reform.Although a large number of relevant studies have focused on the effective paths to curriculum-based ideological and political education in specific courses,there are few studies on how to integrate ideological and political education contents into particular courses under specific educational concepts and by particular teaching methods.Thus,this paper will explore how to improve the teaching effectiveness of curriculumbased ideological and political education in College English course with the OBE concept as the driving force and the case teaching method as the means.Finally,a few thoughts on the application of case teaching method in College English course are offered.展开更多
Introduction Climate change is intensifying extreme heat events,positioning heat-related illness as an escalating public health threat.However,multiprovincial,individual-level evidence quantifying the association betw...Introduction Climate change is intensifying extreme heat events,positioning heat-related illness as an escalating public health threat.However,multiprovincial,individual-level evidence quantifying the association between elevated temperatures and heatrelated illness in China remains limited.Methods This multi-provincial study employed a time-stratified case-crossover design.Individual heatrelated illness case data(2013–2022)were obtained from the Heat-related Illness Report System,which collects reports from local healthcare facilities and CDCs across 11 provincial-level administrative divisions(PLADs).We evaluated associations between daily mean and maximum temperatures and heatrelated illness risk across multiple lag periods(lag0 to lag07),with lag01 designated a priori as the primary exposure window.Effect estimates are presented as relative risks(RR)and percentage changes in RR per 1℃ temperature increase.Subgroup analyses examined potential effect modification by sex,age,heat-related illness subtype,heat intensity,and geographic location.Results Between 2013 and 2022,53,061 heatrelated illness cases were recorded across study areas,with annual counts rising throughout the decade and reaching a peak of 14,025 in 2022.Although mild cases predominated each year(maximum 83.0%in 2015),the proportion of severe cases exhibited a concerning gradual increase.Regarding temperature associations,each 1℃ increase in daily mean temperature corresponded to a 21.03%(95%CI:20.59,21.47)elevation in the RR of heat-related illness.Daily maximum temperature demonstrated a comparable pattern,though risk estimates were marginally lower.Conclusion This study demonstrates a clear upward trend in heat-related illness incidence linked to climate change and confirms that elevated temperatures significantly increase disease risk.The escalating health burden necessitates urgent development and implementation of targeted heat-health action plans to protect vulnerable populations.展开更多
基金This work was financially supported by the Science Foundation Project in Heilongjiang Province of China(No.QC2018047).
文摘There has been lack of work efforts on how to optimize cementing and completing parameters in order to prevent casing failure induced by formation slippage in pertroleum industry scope.Once the weak plane fails,the formation will become easily undertaken slippage across a large area along its interface.The plenty of horizontal planes of weakness in reservoir formations,as reported for a number of oilfields,can easily undertaken slippage once it fails.To address the problem,three-dimensional finite element models were established by taking into considerations the elastoplastic mechanical characteristics of both the casing and the near-wellbore rock.Two types of casing impairment scenarios were considered:Casing collapse(that causes tubing stuck in the well)and complete casing shear-off.In this study,the critical slip displacement of casing shear damage under both cemented and un-cemented conditions was calculated,and the critical displacement of casing with various wall thicknesses and steel grades was compared.A new cementing practice for the Daqing oilfield was then proposed by optimizing casing parameters according to API standards,and a new research method was also put forward by proposing new casing materials to effectively mitigate casing failure caused by formation slippage for the future.Modeling results indicate that the stress and deformation associated with casing in the un-cemented condition is more diffused and the critical slippage displacement is larger than that in the cemented condition.Therefore,the un-cemented condition is more effective in preventing casing shear failure and easier for casing repair,for the case of casing damage caused by formation shear slippage.Casing elongation is the key parameter of casing shear failure in the un-cemented condition.Lower grade casing exhibits a larger critical slippage displacement because of its higher elongation capacity under stress.Casing with lower grade and smaller thickness provides more advantages in preventing casing damage in formations abundant with horizontal weak layers.If the elongation of casing can be largely improved,the critical displacement value can be increased by 21.40%.Higher grade and thicker casing is adapted for mitigate casing failure caused by formation slippage.
基金supports were received from the National Key Research and Development Program of China(2024YFE0208600)New Energy Joint Laboratory of China Southern Power Grid Corporation(GDXNY2024KF03)+2 种基金the National Natural Science Foundation of China(Grant No.U24B2090)National Key R&D Program(No.2022YFB4201300)Science and Technology Project of Huaneng Group(HNKJ24-H78).
文摘The jacket structure and transition piece comprise the supporting structure of a bottom-fixed offshore wind turbine(OWT)connected to the steel tower,which determines the overall structural dynamic performance of the entire OWT.Ideally,optimal performance can be realized by effectively coordinating two components,notwithstanding their separate design processes.In pursuit of this objective,this paper proposes a concurrent design methodology for the jacket structure and transition piece by exploiting topology optimization(TO).The TO for a three-legged jacket foundation is formulated by minimizing static compliance.In contrast to conventional TO,two separated volume fractions are imposed upon the structural design domain of the jacket structure and transition piece to ensure continuity.A 5 MW(megawatt)OWT supported by a four-legged or three-legged jacket substructure is under investigation.The external loads are derived from various design load cases that are acquired using the commercial software platform DNV Bladed(Det Norske Veritas).Through a comparative analysis of the fundamental frequency and maximum nodal deformation,it was found that the optimized solution demonstrates a reduced weight and superior stiffness.The findings demonstrate the present concurrent design approach using TO can yield significant benefits by reducing the overall design cycle and enhancing the feasibility of the final design.
文摘The traditional teaching methods of one-way cultivation of students can no longer meet the requirements of talent cultivation at this stage.The issue of how to promote students from passive acceptance to the independent cognitive understanding stage(i.e.deep learning)has become the focus of geography teaching.Therefore,under the guidance of deep learning theory,this paper takes the“landforms”knowledge unit of the Humanistic Education Edition as an example,improves the classroom teaching means through the unit teaching mode,reconstructs the“landforms”teaching unit,and explores the specific teaching of high school geography unit based on deep learning.This study provides a good example and guidelines for high school geography teaching and learning.
文摘Curriculum ideology and politics is the key to carry out the mission of educating people in colleges and universities in the new era.On the problem of integrating the linear algebra course into the ideological and political education,it was expounded from four aspects:the necessity of integrating the course ideology and politics into the teaching of linear algebra,exploring curriculum ideological and political elements,the case design of integrating the course ideology and politics teaching,and the expected effect of integrating linear algebra courses into ideological and political education in the curriculum,in order to have the reference and help function to the educator.
基金The Teaching Reform Project in Jiangxi Province-the Application of BIM Simulation Information Technology in the Teaching of Engineering Valuation Course Group(JXJG-19-2-48)Jiangxi Educational Planning Project-Research on the Realization of Synergistic Effect of BIM and MOOC in Higher Engineering Education(16YB014).
文摘In higher engineering education,professional courses and ideological and political theory courses go in the same direction,which is an important task of the current professional curriculum construction.This paper introduces the key and difficult problems in the teaching content of the course Engineering Valuation in the Department of Engineering Management and Real Estate of Jiangxi Normal University.Based on the characteristics of simulation information technology such as BIM and VR and the differences of ideological and political elements,it updates and improves the cases of courses for ideological and political education,gives full play to the synergistic effect,and realizes the"triple"talent training goal of knowledge,ability and literacy.
基金A general project granted by NingBo Education Science Planning in 2020——A Research on the Application of Case Teaching Method in“curriculum-based Ideological and political education”in College English Course under the Idea of OBE(No.:2020ygh033).
文摘Since the idea of“Curriculum-Based Ideological and Political Education”was formally proposed in 2016,it has rapidly become a research hotspot in education reform.Although a large number of relevant studies have focused on the effective paths to curriculum-based ideological and political education in specific courses,there are few studies on how to integrate ideological and political education contents into particular courses under specific educational concepts and by particular teaching methods.Thus,this paper will explore how to improve the teaching effectiveness of curriculumbased ideological and political education in College English course with the OBE concept as the driving force and the case teaching method as the means.Finally,a few thoughts on the application of case teaching method in College English course are offered.
基金Supported by the Major Project of Guangzhou National Laboratory(No.GZNL2024A01025)the National Natural Science Foundation of China(Grant No.52272340).
文摘Introduction Climate change is intensifying extreme heat events,positioning heat-related illness as an escalating public health threat.However,multiprovincial,individual-level evidence quantifying the association between elevated temperatures and heatrelated illness in China remains limited.Methods This multi-provincial study employed a time-stratified case-crossover design.Individual heatrelated illness case data(2013–2022)were obtained from the Heat-related Illness Report System,which collects reports from local healthcare facilities and CDCs across 11 provincial-level administrative divisions(PLADs).We evaluated associations between daily mean and maximum temperatures and heatrelated illness risk across multiple lag periods(lag0 to lag07),with lag01 designated a priori as the primary exposure window.Effect estimates are presented as relative risks(RR)and percentage changes in RR per 1℃ temperature increase.Subgroup analyses examined potential effect modification by sex,age,heat-related illness subtype,heat intensity,and geographic location.Results Between 2013 and 2022,53,061 heatrelated illness cases were recorded across study areas,with annual counts rising throughout the decade and reaching a peak of 14,025 in 2022.Although mild cases predominated each year(maximum 83.0%in 2015),the proportion of severe cases exhibited a concerning gradual increase.Regarding temperature associations,each 1℃ increase in daily mean temperature corresponded to a 21.03%(95%CI:20.59,21.47)elevation in the RR of heat-related illness.Daily maximum temperature demonstrated a comparable pattern,though risk estimates were marginally lower.Conclusion This study demonstrates a clear upward trend in heat-related illness incidence linked to climate change and confirms that elevated temperatures significantly increase disease risk.The escalating health burden necessitates urgent development and implementation of targeted heat-health action plans to protect vulnerable populations.
