Stress corrosion cracking in ancient silver

Abstract

Six cases of ancient silver embrittlement by corrosion are discussed with respect to evidence for stress corrosion cracking. Both intergranular and transgranular cracking can occur, depending on whether there is retained cold-work in the silver. The severity of cracking is influenced by a combination of factors, including the amount of cold-work in the silver and the burial environment. The burial environment is important for two reasons. Firstly, the soil weight can induce high stresses, particularly in hollow, thin-walled, and incompletely filled-in artefacts. Secondly, grave burials can result in more aggressive soil environments owing to high salinity from body decomposition.     

Stress in international work: Stressors and coping strategies of RNGO international directors

This study examines how international directors in religiously-affiliated nongovernmental organizations (RNGOs) cope with workplace stress. Interviews were conducted with directors from eight RNGOs who oversee programs in seven international regions. Findings reveal they experience three major stressors: difficulties communicating with others abroad, lack of funds, and dealing with constant travel. Overall, directors encounter these unique stressors due to the international demands of RNGO work, including international travel, fundraising for international programs, and intercultural communication. Moreover, they cope with stressors by striving for physical/mental health, pursuing/providing education, putting family first, seeking support, facilitating stakeholder communication, and planning ahead. Directors rely on problem-centered and emotion-centered coping, but they also describe the beneficial outcomes of avoidance-centered coping. Since only a few directors use prayer as a coping strategy, RNGOs must recognize that employees rely on secular and spiritual coping when developing organizational practices and programs related to stress management.     

残余应力及其本质探讨

残余应力是各种加工工艺产生的一种现象,是能量储存不均匀造成的,是材料内部不均匀塑性变形的结果,其本质是晶格畸变,而晶格畸变很大程度上是由位错引起的。根据等直纯弯曲梁建立了残余应力的力学模型,探讨了残余应力调整的方法。     

2003年2月24日新疆巴楚—伽师Ms6.8地震的静态库仑应力触发作用

2003年2月24日新疆巴楚—伽师发生Ms6.8地震,截止到2004年6月30日发生了7次Mw5以上的中强余震,序列的余震丰富、强度大。本文求算了Ms6.8主震及其序列中主震和中强余震共同在后续中强余震（7次Mw5.0以上余震）破裂面上产生的静态库仑破裂应力变化情况。考虑到震中定位的误差,分几种情况分别讨论了此次Ms6.8主震及其中强余震产生的库仑破裂应力变化情况,并定量分析了Ms6.8地震序列静态库仑破裂应力变化与断层类型的关系及其静态应力触发模型作用的延迟时间和空间范围。认为采用哈佛大学矩心矩张量目录的震源机制解、矩心深度和新疆震中定位结果较合理,由此得到的7次中强余震均发生在库仑破裂应力增加的区域。综合分析表明,巴楚—伽师Ms6.8主震对后续中强余震具有一定的触发作用,而中强余震之间的触发作用不显著。但由于目前震源定位精度的限制,不能肯定序列中7次中强余震是完全受Ms6.8主震触发而发生的。     

非晶材料磁滞损耗弛豫的唯象研究

将应力场与磁场进行类比,导出了非晶磁介质磁滞损耗驰豫的新的规律.     

电针应力点加夹脊穴治疗下腰伤病46例

分析脊柱生理弯曲解剖结构,结合下腰伤痛多发生在腰骶部的临床表现,提出主穴应力点位于腰骸部劳损组织。作者认为,引起下腰伤痛的病变组织,正好位于应力点。针刺夹脊穴腰段疼痛区,兴奋脊神经后支,血行痛止,以治其标。电针应力点,以针代刀,松解劳损组织,松则不痛,以治其本。介绍电针应力点加夹脊穴治疗下腰伤痛46例,有效率为89％。     

体育活动作为考试应激的应付方法研究

选择特定的考试应激情境，使用心境状态量表（POMS）和锻炼感觉量表（EFI），通过实验比较的方法，目的为研究体育活动作为应付方法降低考试应激的效果，实验结果表明，参与体育活动能够有效地降低考试后产生的应激反应，改善心境状态；体育活动时心境状态的改善与运动愉快感的产生之间存在显著意义的相关关系。     

Dealing with the Demands: Strategies Healthcare Communication Professionals Use to Cope with Workplace Stress

This study examines how healthcare communication professionals (HCPs) cope with workplace stress while working in an inherently stressful industry. In-depth, semi-structured interviews were conducted with 17 HCPs (14 females, 3 males) from seven nonprofit and for-profit hospitals in the midwestern and eastern regions of the United States. Communication positions held by participants included marketing, media/community relations, public information, public relations, corporate communication, and social media. Interviews revealed HCPs use four strategies to cope with workplace stress: prioritizing, seeking colleague support, keeping perspective, and being active. HCPs primarily relied on employee-centered coping strategies, even though all sources of stress were organizationally-based (i.e., workload, lack of resources, client confidentiality). The majority of HCPs emphasized the benefits of using problem-centered (i.e., prioritizing) and emotion-centered (i.e., seeking colleague support) coping strategies. Although mentioned less often, HCPs utilized more avoidance-centered coping strategies (i.e., keeping perspective, being active). More importantly, they highlighted the benefits of using avoidance-centered strategies to help them mentally and physically disengage from workplace stress. Hospital administration should reassess if, and how, they help HCPs effectively cope with workplace stress (i.e., outlets, programs, professional development opportunities) in order to improve the well-being of HCPs and increase the likelihood of organizational success.     

Copper(II) hydroxide on artefacts: Corrosion,conservation, colourants

Copper(II) hydroxide (as the rarely occurring mineral spertiniite) is formed under alkaline, oxidising conditions. It has been observed as a naturally occurring corrosion product of brass in sea water. But most occurrences on copper alloys are due to conservation treatments using basic solutions (sodium hydroxide or ammonia) or to intentional patination. Classical brass centrepieces (c. 1800), ‘cleaned’ with ammonia solution, developed a blue spertiniite patina in gaps, where evaporation was hindered. Additional to the danger of stress corrosion cracking this is another reason now outlawing this treatment. Copper pigment layers will transform to copper hydroxide when exposed to bases. The treatment of basic copper salts with bases has been used intentionally in the production of Bremen blue and similar pigments which can be composed of copper hydroxide as well.     

Mindfulness meditation for future early childhood teachers in Japan

To prevent future burnout and turnover among early childhood education students, mindfulness training may hold promise as a measure. A lab-based pilot and classroom-based feasibility study was designed to investigate an effective way to introduce mindfulness meditation. Results suggested that two types of audio-guided mindfulness meditation, a sitting meditation and a compassion meditation reduced stress level, and that the compassion meditation was perceived as more comfortable than the sitting meditation. As a tentative conclusion, the compassion meditation may be introduced first before the sitting meditation. Additional studies should examine the effects of longer-term meditation practice on teaching career development.