Work and rest in the long-distance road transport industry in Australia

To date management of fatigue in professional drivers has largely focused on strategies that limit the amount of time spent on the job. These approaches have, however, not taken into account the well-documented effect of time of day. Consequently, the likely impact of the pattern and timing of work and rest has received little attention. The results revealed that the group of drivers who did the shortest trips and worked the shortest weekly hours were the lowest reporters of fatigue, although longer hours were not always associated with the highest reporting of fatigue. In contrast, the shortest working hours were associated with earliest onset of fatigue. For all drivers, the influence of circadian rhythms was evident in the occurrence of fatigue, with better management of the problem evident among drivers who were able to arrange the timing of rest to more closely coincide with periods of fatigue. Thus, time of day appeared to be a more important influence in determining effective rest than did period of work. These findings raise questions about the validity of the assumption underlying work hour regulations for long-distance drivers which, currently, are universally based on duration of work.     

试析现代主义艺术“审美疲惫”生成原因——从现代主义艺术作品的大众审美谈起

在国内大众对现代主义艺术进行审美时,常会发生"审美疲惫"心理现象.而这就与显现于审美过程中的审美震撼力是否能够转化为艺术魅力有关.因此有必要对现代主义艺术作品的艺术特性与审美大众的期待心理的互联互动历程进行分析,以探究"审美疲惫"的发生过程.     

Signed likelihood ratio tests in the Birnbaum-Saunders regression model

The Birnbaum-Saunders regression model is becoming increasingly popular in lifetime analyses and reliability studies. In this model, the signed likelihood ratio statistic provides the basis for testing inference and construction of confidence limits for a single parameter of interest. We focus on the small sample case, where the standard normal distribution gives a poor approximation to the true distribution of the statistic. We derive three adjusted signed likelihood ratio statistics that lead to very accurate inference even for very small samples. Two empirical applications are presented.     

12-h workdays: current knowledge and future directions

Work schedules other than those based on the traditional 8-h workday duration have become much more common in recent years. Many such schedules compress the work week into three or four longer workdays and include an increased number of days off. In particular, rosters based on 12-h workdays have gained in popularity, and such rosters have been the focus of considerable research. The literature on 12-h workdays is, however, full of inconsistencies. Not surprisingly, there is considerable evidence from some of these studies that 12-h shifts tend to cause more fatigue than 8-h shifts. This extra fatigue may be associated with lower work efficiency, and with more errors and accidents. There is also strong evidence that workers prefer 12-h shifts due to some perceived advantages. The present paper reviews and examines these studies and their findings and discusses some possible reasons for the apparent contradictions in reported findings. Directions for decision makers and future research are suggested.     

An adaptive estimatcr frequently used in material fatigue testing

Small sample sizes in material fatigue tests give rise to an adaptive estimator of the 100(1-P)% normal percentile, which is the 100P% survival load. The mean squared relative efficiency of the best invariant estimator of normal percentiles to the adaptive estimator is dependent upon the unknown parameters only through the coefficient of variation. The adaptive estimator is shown to be more locally efficient than tl-:ebest invariant estimator over a subset of the parameter space. However, in the extreme values of P the coverage probabilities of the adaptive estimator provide little more protection than a traditional point estimator over the range of preference based on mean squared relative efficiency.     

The impact of rest breaks upon accident risk,fatigue and performance: A review

This review's primary objective is to identify research examining the impact of rest breaks uponaccident risk in industrial settings. In the absence of much directly relevant research, the focus isbroadened to consider the impact of rest breaks upon performance and fatige, as well asepidemioogical evidence, in both transport and non-transport settings. Relevant studies are identifiedfrom a range of electronic sources. In general, regular rest breaks can be an effective means ofmaintaining performance, managing fatigue and controlling the accumulation of risk over prolongedtask perfonmance. While two-hourly breaks are common in many industrial settings, the scheduling ofadditional micro-breaks can be beneficial under at least some circumstances. While some evidencesupports allowing workers to take rest breaks that coincide with periods of heightened fatigue,workers sometims fail to take adequate breaks when they are needed. There is little hard evidenceconcerning the optimun length of rest breaks (other than for heavy physical work), or to support thecontention that increased rest-breaks can off-set the negative inpact of extending shift durations, or tosuggest that rest breaks counteract the neptive impacts of circadian variations in alertness, unless theyinvolve taking a nap or caffeine. The scarcity of epidemiological evidence in this area highlights theneed for more research.     

基于COSMOSWORKS悬臂主轴的力学性能分析研究

采用Solidworks Cosmosworks有限元方法，对掘进机悬臂主轴进行静态分析、校核强度并进行疲劳寿命分析。与传统的零件强度校核方法比较，有限元方法更准确、更符合实际，得到的分析结果可以为产品的设计、改进提供参考，也可以为掘进机的动态性能分析打下基础。     

疲劳强度设计在机械零件中的应用

疲劳强度在机械零件设计中的应用不同于静强度设计，由于设计时计入了应力集中、表面状态、尺寸及加载方式等影响因素，故更加符合动态实际情况．本文阐述了正确选择影响零件疲劳极限主要系数的途径，介绍了疲劳强度设计在机械零件中的几种计算方法及应用。     

Small-Sample Corrections for Score Tests in Birnbaum–Saunders Regressions

In this article, we deal with the issue of performing accurate small-sample inference in the Birnbaum–Saunders regression model, which can be useful for modeling lifetime or reliability data. We derive a Bartlett-type correction for the score test and numerically compare the corrected test with the usual score test and some other competitors.     

An Empirical Investigation of the Envelope Theory

Abstract

The Envelope Theory stipulates that, if perceived and expended energy levels are kept relatively at the same levels, people with Chronic Fatigue Syndrome (CFS) will slowly gain strength and energy. Based on this theory, an intervention was developed that provided feedback to participants with CFS about discrepancies in perceived versus expended energy levels. As part of this intervention, a buddy was provided to help with household tasks in order to reduce excessive energy expenditures. Post-test results revealed a decrease in participants' fatigue severity ratings, and positive changes were recorded for five CFS somatic symptoms. Participants also reported increases in optimism regarding recovery, positive re-interpretation and growth, and information seeking behavior. The implications of these findings are discussed.