Results 31 to 40 of about 18,303 (165)
Unpacking Welfare Deservingness Theory: Evidence From the Perceived Deservingness of Gig Workers
Policy Studies Journal, EarlyView.ABSTRACT The theory of welfare deservingness provides valuable insights into the social legitimacy of welfare programs and the principles underlying policy design. In examining the question of who deserves what and why, established deservingness criteria emphasize that individuals demonstrating motivation to work (“reciprocity”) are typically perceived
Juhyun Bae
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2018 选取几何法及撑杆控制面积法确定环索预应力比,选取支座径向位移相等准则及网壳顶点竖向位移相等准则确定环索预应力幅值,将它们进行交叉组合构成4个环索预应力设计方案。另外还选取刚性索法及改进刚性索法作为环索预应力设计方案。以2008年北京奥运会羽毛球馆屋盖弦支穹顶结构为背景建立了算例结构模型。以结构重量为目标函数,考虑构件的长细比约束、强度应力约束、稳定应力约束和结构位移约束,考虑12个设计荷载工况。基于上述6个环索预应力设计方案,采用ANSYS编程语言分别编制结构优化设计程序,以确定最优的环索预应力设计方案。
刘树堂, 黄卫林
doaj
疲劳荷载特性对8.8级M24高强度螺栓疲劳裂纹扩展机理影响探析
Jianzhu Gangjiegou Jinzhan, 2023 为研究常幅疲劳荷载特性对高强度螺栓疲劳裂纹扩展的影响，针对钢结构端板连接用8.8级M24高强度螺栓在不同应力比/应力幅作用下常幅疲劳试验所得到的24个试件断口形貌进行定量分析，并采用ABAQUS软件数值模拟高强度螺栓应力集中情况，探讨含初始裂纹高强度螺栓裂纹尖端应力强度因子与荷载特性、预制裂纹形状之间的关系。结果表明：在轴向受拉疲劳荷载作用下，螺母与螺栓啮合第1圈螺纹处为疲劳断裂最不利位置；试件断口稳定扩展区面积与应力比/应力幅呈负相关，快速扩展区面积与应力比/应力幅呈正相关 ...
樊丽轩 +4 more
doaj
Pseudo static test for pre-cast segmental bridge columns with dry joints [PDF]
, 2011 为了比较节段拼装桥墩与整体现浇桥墩之间抗震性能的差异,以是否存在预应力钢筋、不同施工方法、预应力筋的位置和粘结状态、是否存在耗能钢筋等为试验参数,设计了一个包含五种不同构造类型混凝土桥墩的试验方案。采用拟静力试验方法比较分析了这五种不同构造类型混凝土桥墩的破坏形态、易损部位、荷载位移滞回曲线、节段拼装桥墩接缝的开展、拟静力残余位移、曲率分布、耗能能力、粘滞阻尼比等,得到了三种节段拼装桥墩、整体现浇钢筋混凝土桥墩和预应力混凝土桥墩之间拟静力行为的异同。试验结果表明 ...
林铁良, 葛继平, 高婧
core
Compliance in Regulatory Gray Areas: The Case of the Organic Seed Standard
Policy Studies Journal, EarlyView.ABSTRACT Adaptive regulations, designed to balance flexibility with accountability, can embed provisions that unintentionally leave room for firms to shirk on their responsibilities by exploiting flexibility. We call these provisions “regulatory gray areas,” and ask: how should we understand (non‐)compliance in adaptive regulatory settings?
Liza Wood +3 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2016 针对预应力钢柱基底含摩擦型消能装置的耐震性能进行研究,探讨初始钢绞线预应力与消能装置的影响。通过钢绞线施拉预应力接合钢柱与基础,用来提供钢柱自复位能力;消能装置采用摩擦型消能,提供柱构件与基础接合的滞回消能能力,因此柱构件在受震后拥有自复位与无残余变形特性。研究参数包含初始预应力大小、摩擦消能面积与摩擦型消能装置的位置。通过理论推导建立预应力与消能装置在钢柱与基础接合的性能模式,进而设计试件进行试验来验证其性能。试验结果表明,柱与基础接合面有开启与闭合的现象;提高摩擦型消能装置螺栓的预应力量 ...
陈诚直 +3 more
doaj
, 2007 以北京城市轻轨线某预应力混凝土高架桥连续箱梁的实桥应变观测试验为基础,利用实验数据进行回归分析,阐述了梁体时效变形的发展规律及其对轻轨道路二期施工的影响.实验结果表明:以应变发展规律得出的时效变形系数在数值上能够很好地估算梁体的后期变形增量,合理安排二期施工时间,在该高架桥预应力筋张拉2~3个月后安装桥上轨道设施,梁体后期变形相对增量最大值约为3~4 mm左右,可完全满足钢轨扣件调节量要求 ...
姚谦峰 +3 more
core
A novel approach for applying active surface pre-stress on surrounding rocks of roadways by backfilling behind surface support [PDF]
In response to the poor active support effect of the surface protection components in soft coal roadway and the continuous expansion of the broken range of local exposed surrounding rock, which leads to the failure of anchor rod and cables, a mesh ...
Fuqiang GAO +4 more
core +1 more source
Jellyfish blooms restructure plankton dynamics and trophic linkages in coastal waters
Functional Ecology, Volume 40, Issue 5, Page 1443-1460, May 2026.Read the free Plain Language Summary for this article on the Journal blog. Abstract Jellyfish blooms are increasing globally in frequency and intensity, introducing complex ecological interactions, yet the mechanisms by which they alter ecosystem structure remain poorly characterized due to a lack of sustained field observations.
Pengpeng Wang +4 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan横向全宽预应力预制桥面板与分块预制桥面板相比，整体性更好，施工更快捷，在装配式组合梁桥中具有较好的应用前景。负弯矩作用下预制桥面板的湿接缝连接是受力的关键部位，为此对负弯矩作用下的全宽预应力预制桥面板组合梁的力学性能进行研究，明确了横向预应力筋数量、预应力筋布置方式、剪力连接程度、接缝处材料对结构破坏模式、开裂荷载、抗弯承载力、荷载-位移曲线等力学特性的影响规律，揭示了预制板接缝处的应力分布规律；针对完全剪力连接的预制桥面板组合梁，提出了负弯矩作用下挠度计算的改进有效惯性矩叠加法 ...
陈娟 +4 more
doaj +2 more sources