水污染已成为当前急需解决的难题,传统方法和手段已不能满足监管应用的需求。结合设计和实现一个水文监管系统的实际项目,阐述系统的基本构架和实现方式。利用Java EE 7和Web Socket协议实现了全双工通信,很好地满足了水文信息实时监测...水污染已成为当前急需解决的难题,传统方法和手段已不能满足监管应用的需求。结合设计和实现一个水文监管系统的实际项目,阐述系统的基本构架和实现方式。利用Java EE 7和Web Socket协议实现了全双工通信,很好地满足了水文信息实时监测、管理、分析和查询需求。实际应用表明,该系统不仅能减少网络通信阻塞和计算资源浪费,同时也提升了分布式系统数据实时交互和访问的性能。展开更多
This study examines the temperature field distribution characteristics and temperature effects during the prefabrication of composite box girders with corrugated steel webs(CBGCSWs),aiming to provide practical recomme...This study examines the temperature field distribution characteristics and temperature effects during the prefabrication of composite box girders with corrugated steel webs(CBGCSWs),aiming to provide practical recommendations for controlling temperature-induced cracking and technical guidance for concrete mix proportions and placement processes.Based on field measurement data,a three-dimensional finite element model was developed to simulate the temperature effects at critical locations during the prefabrication phase.By varying the concrete mix proportions,initial casting temperature,and ambient temperature,the study elucidates the variation patterns of the temperature field during precast placement.The results show that the temperature rise caused by hydration heat increases with higher cement and fly ash content,whereas reducing cement and using minimal fly ash effectively lower the hydration temperature.However,the influence of fly ash on prestress losses should be carefully evaluated during the design phase.Higher initial casting temperatures accelerate hydration rates,leading to a rapid temperature rise.Significant differences between the initial casting and ambient temperatures result in larger residual temperature stresses.Based on concrete mix proportions,curing conditions,and ambient temperatures,three recommended casting temperature ranges were identified:5℃–10℃,10℃–25℃,and 25℃–30℃.Variations in the average ambient temperature affect the peak temperature of the hydration reaction and indirectly influence the final temperature distribution of the concrete structure.Optimizing the demolding time and applying geotextiles and water curing effectively reduces the peak temperature,maximum internal-to-surface temperature gradients,and surface tensile stresses,thereby mitigating the risk of temperature-induced cracking.展开更多
文摘水污染已成为当前急需解决的难题,传统方法和手段已不能满足监管应用的需求。结合设计和实现一个水文监管系统的实际项目,阐述系统的基本构架和实现方式。利用Java EE 7和Web Socket协议实现了全双工通信,很好地满足了水文信息实时监测、管理、分析和查询需求。实际应用表明,该系统不仅能减少网络通信阻塞和计算资源浪费,同时也提升了分布式系统数据实时交互和访问的性能。
基金supported by the National Natural Science Foundation of China(U22A20598,52279113)Key Research and Development Special Program of Henan Province(241111322500)Support Plan for University Science and Technology Innovation Team of Henan Province(24IRTSTHN009).
文摘This study examines the temperature field distribution characteristics and temperature effects during the prefabrication of composite box girders with corrugated steel webs(CBGCSWs),aiming to provide practical recommendations for controlling temperature-induced cracking and technical guidance for concrete mix proportions and placement processes.Based on field measurement data,a three-dimensional finite element model was developed to simulate the temperature effects at critical locations during the prefabrication phase.By varying the concrete mix proportions,initial casting temperature,and ambient temperature,the study elucidates the variation patterns of the temperature field during precast placement.The results show that the temperature rise caused by hydration heat increases with higher cement and fly ash content,whereas reducing cement and using minimal fly ash effectively lower the hydration temperature.However,the influence of fly ash on prestress losses should be carefully evaluated during the design phase.Higher initial casting temperatures accelerate hydration rates,leading to a rapid temperature rise.Significant differences between the initial casting and ambient temperatures result in larger residual temperature stresses.Based on concrete mix proportions,curing conditions,and ambient temperatures,three recommended casting temperature ranges were identified:5℃–10℃,10℃–25℃,and 25℃–30℃.Variations in the average ambient temperature affect the peak temperature of the hydration reaction and indirectly influence the final temperature distribution of the concrete structure.Optimizing the demolding time and applying geotextiles and water curing effectively reduces the peak temperature,maximum internal-to-surface temperature gradients,and surface tensile stresses,thereby mitigating the risk of temperature-induced cracking.
