Thriving on challenge stressors? Exploring time pressure and learning demands as antecedents of thriving at work

In the conceptualization of thriving at work, it is emphasized that employees' learning and vitality are two equally important components of thriving and that thriving is facilitated by contextual features and available resources. In this study, we examined the effects of two challenge stressors (time pressure and learning demands) on thriving at work. Based on the literature on challenge and hindrance stressors, we proposed that challenge stressors positively affect learning and negatively affect vitality. To uncover underlying mechanisms, we measured challenge appraisal and hindrance appraisal of work situations in a diary study. A sample of 124 knowledge workers responded to three daily surveys (before the lunch break, during the afternoon, and at the end of the workday) for a period of five workdays. Results indicate that the indirect effects of learning demands and time pressure on learning are mediated by challenge appraisal, whereas indirect effects of learning demands on vitality are mediated by hindrance appraisal. Overall, our study shows that challenge stressors have a positive total effect on learning but no total effect on vitality. These differential relationships call for a finer distinction between the two components of thriving at work in future research. Copyright © 2016 The Authors Journal of Organizational Behavior Published by John Wiley & Sons Ltd.     

被保护层双重卸压特性研究

为探索复合煤层群保护层开采时在双重卸压条件下被保护层的不同卸压特性,采用物理相似模拟试验和计算机数值模拟来研究其双重卸压规律。对比分析被保护层的膨胀率和卸压率后发现:在双重卸压条件下,被保护层的膨胀变形呈现"M"形态,膨胀率在不同时空下表现出叠加特性;另外,煤岩体的弹性势能因受首采保护层的影响而释放,被保护层卸压率表现出卸压区域边缘不连续而卸压程度和范围均增加的特点。最后,现场测试计算得到被保护层的透气性系数,其变化规律证实双重卸压效果明显。     

模拟高低空交变环境下30CrMnSiNi2A钢力学性能研究

目的研究30CrMnSiNi2A钢制腔体的力学性能影响及演化规律。方法借助高低温低气压试验和中性盐雾试验交替进行,模拟高低空交替变化的腐蚀环境。通过比较静力拉伸试验和疲劳试验的结果,进一步揭示预腐蚀对静力拉伸性能和疲劳性能的影响。结果经过预腐蚀处理,30CrMnSiNi2A钢制腔体的力学抗拉强度下降了0.73%,规定塑延伸强度上升了0.04%,断后伸长率下降了0.95%。疲劳寿命数据与对数疲劳寿命数据均符合正态分布,未发生明显变化。结论高低空交变环境下,腔体内部会发生一定程度的腐蚀,但由于腐蚀程度较小,对30CrMnSiNi2A钢力学性能影响不大。     

海洋水下滑翔机浮力调节系统的设计与实验

目的提高海洋滑翔机浮力调节系统的可靠性,进一步降低系统功耗,设计气压与液压结合的低功耗浮力调节系统。方法基于理论分析确定系统的体积控制量,设计气压调节模块以保证高压油泵的正常工作与回油的顺利进行。利用有限元方法分析承压管路的可靠性,通过实验测试,验证浮力系统的响应性能。结果浮力系统的排油效率随着外压的增大而减小,2MPa的压力会使出油率降低3%左右,同时功耗增加50%左右。在大气压力环境下,依靠系统内负压,400 s即可完成回油600 mL,完成上浮到下潜的转换。结论设计的浮力调节系统的气压调节装置能以较低的功耗保障主泵的正常工作,同时保障回油过程的通畅,满足海洋滑翔机对浮力调节的要求,可以应用于一般海洋深度的水下滑翔机。     

混凝土高温爆裂性能影响因素及预防措施综述

对混凝土高温爆裂成因进行总结,综述高温下混凝土内部蒸汽压力的测试手段、降低混凝土内部蒸汽压力方法、提高混凝土在高温中的抗高温爆裂性能的方法,以及总结了升温速率对混凝土高温爆裂的影响,并提出了几种预防混凝土高温爆裂的措施,为混凝土高温爆裂研究提供依据。     

湿式旋流弦切除尘器性能实验研究

旋流弦切除尘器作为一种新型湿式除尘器,具有良好的特性。本文在所建立的实验系统上,按湿式除尘性能测试的相关规范,研究了除尘风速、弦切速度与除尘器效率和压力损失间的关系。实验结果显示:在液气比为定值时(0.05 L/m~3),在实验风速范围内,除尘效率存在极值;压力损失符合流体力学的局部阻力规律,并拟合出了除尘器的局部阻力系数。     

Lessons learned from a supercritical pressure BLEVE in Nihon Dempa Kogyo Crystal Inc.

On December 7, 2009, a 50-foot-tall high-pressure vessel ruptured in the Nihon Dempa Kogyo Crystal, Inc. facility in Belvidere, Illinois. Several projectiles rapidly traveled outward from the facility, killing a truck driver 650 feet away and injuring an employee in another building 435 feet away. This paper summarizes the lessons learned from this incident both on causal and consequential aspects. Stress corrosion cracking was identified as the failure mechanism by the U.S. Chemical Safety and Hazard Investigation Board. After analyzing the operating conditions and the aftermath, this incident has been identified as a Boiling Liquid Expanding Vapor Explosion (BLEVE) under a supercritical pressure. A consequence analysis of the incident is performed where overpressure and fragment distance are calculated, together with safety distance estimation. Additionally, other safety-related problems, such as safety culture, management inside the corporation, and communication between this facility and the government are discussed.     

炼油火炬系统水封罐设计压力研究

水封罐作为炼油火炬系统防止回火爆炸的重要安全设施,其设计应能保证在发生回火爆炸事故时不被破坏。采用数值模拟技术,利用FLACS工具,建立水封罐三维模型,模拟计算水封罐内的典型气体爆炸,据此提出水封罐的设计压力。结果表明:烃类气体(如甲烷、丙烷)在水封罐密闭空间内发生爆炸产生的压力为气体初始压力(绝压)的7~8倍,氢气爆炸产生的压力为气体初始压力(绝压)的10~12倍。对于炼油火炬系统,建议富氢气体排放系统的水封罐设计压力不低于1.0MPa(绝压),一般烃类火炬气排放系统的水封罐设计压力不低于0.7MPa(绝压)。     

足底压力测量技术在鞋靴设计中的应用及进展

足底压力测量技术是用来研究穿鞋状态下足-鞋界面压力分布的必要手段,对生物力学和临床医学等的相关理论和技术都有着重要的作用,也为指导人们健康穿鞋与科学制鞋带来了科学理论依据。本文概要地介绍足底压力测量技术发展历史及其在鞋靴设计领域中的应用方向。