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1.
INTRODUCTION: Numerous studies have documented an increased frequency of vehicular crashes, traffic citations, driving performance deficits, and driving-related cognitive impairments in teens and adults with attention deficit hyperactivity disorder. METHOD: The present study evaluated the effects of two single, acute doses of methylphenidate (10 and 20 mg) and a placebo on the driving performance of 53 adults with ADHD (mean age=37 years, range=18-65) using a virtual reality driving simulator, examiner and self-ratings of simulator performance, and a continuous performance test (CPT) to evaluate attention and inhibition. A double-blind, drug-placebo, within-subjects crossover design was used in which all participants were tested at baseline and then experienced all three drug conditions. RESULTS: A significant beneficial effect for the high dose of medication was observed on impulsiveness on CPT, variability of steering in the standard driving course, and driving speed during the obstacle course. A beneficial effect of the low dose of medication also was evident on turn signal use during the standard driving course. An apparent practice effect was noted on some of the simulator measures between the baseline and subsequent testing sessions that may have interacted with and thereby obscured drug effects on those measures. CONCLUSIONS: The results, when placed in the context of prior studies of stimulants on driving performance, continue to recommend their clinical use as one means of reducing the driving risks in ADHD teens and adults. IMPACT ON INDUSTRY: Given the significantly higher risk of adverse driving outcomes associated with ADHD, industry needs to better screen for ADHD among employees who drive as part of employment so as to improve safety and reduce costs. Use of stimulants to treat the adult ADHD driver may reduce safety risks. 相似文献
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ABSTRACTObjective: This study analyzed the influence of reference sensor inputs from anthropomorphic test devices (ATDs) versus postmortem human subjects (PMHSs) on simulations of frontal blunt impacts to the advanced combat helmet (ACH). Methods: A rigid-arm pendulum was used to generate frontal impacts to ACHs mounted on ATDs and PMHS. An appropriately sized ACH was selected according to standard fitting guidelines. The National Operating Committee on Standards for Athletic Equipment (NOCSAE) head was selected for ATD tests due to shape features that enabled a realistic helmet fit. A custom procedure was used to mount a reference sensor internally near the center of gravity (CG) of the PMHS. Reference sensor data from the head CG were used as inputs for the Simulated Injury Monitor (SIMon). Brain responses were assessed with the cumulative strain damage measure set at 10%, or CSDM(10). Results: Compared to ATD tests, PMHS tests produced 18.7% higher peak linear accelerations and 5.2% higher peak angular velocities. Average times to peak for linear accelerations were relatively similar between ATDs (5.5?ms) and PMHSs (5.8?ms). However, times to peak for angular velocities were higher by a factor of up to 3.4 for PMHSs compared to ATDs. Values for were also higher by a factor of up to 13.1 when PMHS inputs were used for SIMon. Conclusions: The preliminary findings of this work indicate that small differences in ATD versus PMHS head kinematics could lead to large differences in strain-derived brain injury metrics such as CSDM. 相似文献
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Objective: Pedestrians are the most vulnerable road users due to the lack of mass, speed, and protection compared to other types of road users. Adverse weather conditions may reduce road friction and visibility and thus increase crash risk. There is limited evidence and considerable discrepancy with regard to impacts of weather conditions on injury severity in the literature. This article investigated factors affecting pedestrian injury severity level under different weather conditions based on a publicly available accident database in Great Britain. Method: Accident data from Great Britain that are publicly available through the STATS19 database were analyzed. Factors associated with pedestrian, driver, and environment were investigated using a novel approach that combines a classification and regression tree with random forest approach. Results: Significant severity predictors under fine weather conditions from the models included speed limits, pedestrian age, light conditions, and vehicle maneuver. Under adverse weather conditions, the significant predictors were pedestrian age, vehicle maneuver, and speed limit. Conclusions: Elderly pedestrians are associated with higher pedestrian injury severities. Higher speed limits increase pedestrian injury severity. Based on the research findings, recommendations are provided to improve pedestrian safety. 相似文献
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The real burden of occupational diseases, specifically work-related musculoskeletal disorders (MSDs), and its impact on workers’ productivity is not known. The situation is critical in developing countries where only cases that cause workers’ disability are recorded. In this study, the incidence of MSDs in Colombia was estimated by using the age and gender specific double incidence rate of repetitive strain injuries diseases in Finland for 2002. The results showed that the estimated number of MSDs recorded in Colombia during 2005 was 23,477 cases at the rate of 11.6 cases per 10,000 workers. The estimated total cost of these MSD cases relative to workers’ productivity was US $171.7 million, representing around 0.2% of Colombia’s Gross Domestic Product for 2005. The systematic appraisal of the incidence of MSDs and their associated cost on workers’ productivity are necessary in developing countries to reduce the costly impact on productivity and to increase workers’ well-being. 相似文献
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为避免作业人员肌肉疲劳累积,预防工作相关肌肉骨骼系统疾患(WMSDs),提出一种基于肌力降幅(FD)-主观疲劳评分(RPE)的肌肉疲劳评价模型。首先设计并开展模拟拉车作业试验,招募10名大学男生参与测试,测量不同时刻右手最大剩余肌力,并记录基于Borg CR-10量表的RPE值;然后归一化处理各时刻FD,建立不同姿势、不同负荷下的3个拉力作业上肢肌肉疲劳评价模型,并结合试验条件分析不同模型之间的差异。研究表明:RPE与FD间有线性关系,RPE-FD关系可能具有姿势属性;所建模型合理,可用于评价拉力作业人员工作过程肌肉疲劳,并可为施力作业过程肌肉疲劳监测与作业任务分析提供依据和手段。 相似文献
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制备了聚乙烯醇/氧化石墨插层纳米复合材料,并用X-射线衍射仪和高分辨电镜对其结构进行了表征.X-射线衍射仪和高分辨电镜的试验结果表明,氧化石墨和聚乙烯醇插层氧化石墨的层间距分别为0.89 nm和1.4nm.该纳米复合材料的热分析和热失重图说明,氧化石墨的加入有利于提高聚乙烯醇/氧化石墨纳米复合材料的玻璃化转变温度和氧化温度,同时也降低了其热释放速率. 相似文献
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为全面了解人工物料搬运(MMH)中拉力作业肌肉疲劳研究现状,深入分析作业过程肌肉疲劳特征,预防肌肉骨骼系统疾患(MSDs),在检索国内外MMH拉力作业肌肉疲劳研究相关成果的基础上,总结5种基本研究方法,并将MMH拉力作业按照工作任务类型和研究对象进行分类,综述其研究所采用的方法及研究结论。最后,评述拉力作业肌肉疲劳现有研究结果,并结合其他作业任务的肌肉疲劳研究成果,展望5个拉力作业肌肉疲劳的研究方向。结果表明:现有拉力作业肌肉疲劳研究主要包括静态作业研究和动态作业研究2个方面,且由静态作业研究向动态作业研究转变;同时采用几种研究方法以全面揭示作业过程肌肉疲劳问题;动态以及间歇作业肌肉疲劳特征、发展规律和预测建模方面的研究较少,是今后的主要研究方向。 相似文献
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采用TMBR+NF/RO组合工艺对湖北省宜昌市某垃圾卫生填埋场渗滤液进行处理,介绍了组合工艺的流程、特点、设备规格、技术参数。TMBR系统对可生化降解COD处理后,COD平均质量浓度为822 mg/L,平均去除率为95.8%,对NH_3-N平均去除率为94.9%;经过NF/RO出水的COD平均值为45 mg/L,NH_3-N均小于25mg/L,达到《生活垃圾填埋场污染控制标准》(GB 16889—2008)的排放标准。组合工艺处理成本为29.5元/m3。 相似文献
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为了解间歇静态拉力作业中人员肌肉疲劳发展特征及其与连续静态拉力作业肌肉疲劳发展的差异,减少肌肉疲劳累积,降低罹患工作相关肌肉骨骼疾患(WMSDs)风险,设计并开展间歇静态拉力作业试验,招募8名大学男生参与试验,测量不同工休比下不同时刻的肌力( F),并记录主观疲劳评分(RPE),然后运用统计学方法分析 F和RPE。研究表明:间歇静态拉力作业不同工休比下 F曲线走向基本一致,作业结束时刻 F值和RPE值均未见统计学显著性差异;组内不同时刻相同部位以及相同部位不同时刻的一些RPE存在显著差异;间歇静态和连续静态拉力作业肌肉疲劳发展存在显著差异,间歇作业中肌肉疲劳累积显著低于连续作业,可考虑采用本文所研究工休比进行拉力作业工作安排,需人力完成的静态作业宜采用间歇静态施力以减缓肌肉疲劳累积。 相似文献
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为进一步提高膨胀型阻燃剂(IFR)对聚甲醛(POM)的阻燃效果,首先将硼酸锌(ZB)与常用IFR(聚磷酸铵-三聚氰胺-季戊四醇)共混制得ZB-IFR复配膨胀阻燃体系的样品,采用熔融共混法制备ZB-IFR/POM复合阻燃材料;然后利用极限氧指数(LOI)测定仪、垂直燃烧(UL-94)测试法、热重分析(TGA)法、扫描电镜(SEM)、锥形量热仪(CONE)及热重-红外(TG-IR)仪等研究ZB-IFR对POM的协效阻燃作用。结果表明:当ZB含量为1%时,所得1.0ZB-IFR/POM的LOI可达55%,UL-94等级为V-0级;其受热膨胀后所得残炭量高,炭层结构致密稳定,且在燃烧过程中的热释放速率(HRR)、质量损失及烟气释放量均最小,火灾性能指数(FPI)相对最高;除此,不含ZB的IFR/POM在受热分解过程中比1.0ZB-IFR/POM放出更多的CO 2,说明ZB的加入能有效地抑制复合阻燃材料的充分燃烧,显示出良好的协效阻燃作用。 相似文献
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为预防手工搬运工人因疲劳引发的职业性肌肉骨骼损伤(WMSDs),综合考虑生产效率和人因工程2个因素,提出考虑搬运时间和能量消耗的双目标模型;采用IGRIP/ERGO和Matlab软件,设计交互式仿真平台;以某汽车刹车片制造公司的手工搬运作业(MMH)为例,应用上述模型进行模拟仿真,得出最优解。结果表明:投入材料数量和生产工序均对能量消耗和作业时间有显著影响,并且能耗和时间的变化率负相关;该模型兼顾生产效率和人因工程2个因素,能够得出最优作业方案;交互式仿真平台有助于控制并预防现代工业生产中的WMSDs风险,使工作环境和作业设计达到人因工程要求。 相似文献
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ObjectiveThe objective of this study was to evaluate repeated patient handling injuries following a multi-factor ergonomic intervention program among health care workers. MethodsThis was a quasi-experimental study which had an intervention group and a non-randomized control group. Data were collected from six hospitals in Saskatchewan, Canada from September 1, 2001 to December 1, 2006. ResultsA total of 1,480 individuals who had a previous injury were eligible for the study. Medium and small size hospitals in the intervention group had significantly fewer repeated injuries than in the control group. Multivariate analysis showed that the intervention group had 38.1% lower odds of having repeated injury compared to the control group, after adjusting for hospital size. ConclusionsThe work-related repeated injury after a multi-factor intervention program was reduced. The synergistic relationships between components of multi-factor intervention and applicability of injury prevention programs to different settings need to be further explored. Impact on IndustryImplementing a multi-factor program with the right equipment and training can lower the risk of injury among health care workers. 相似文献
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针对事故树分析法(FTA)在风险评价中的局限性,在可控飞行撞地(CFIT)事故树的基础上,建立贝叶斯网络(BN).运用推理运算对贝叶斯网络进行定量分析,通过分析计算数据,寻找主要事故致因,并提出对应的改进措施.再将改进措施引入到贝叶斯网络中,评价相关措施的有效性.结果表明,改进措施后,高度设置错误的后验概率最大,将成为预防CFIT的工作重点.最后指出贝叶斯网络方法是对传统的基于故障树分析的风险评价方法的有益改进. 相似文献
14.
Blowout Preventer (BOP) has maintained its function as a safety barrier and the last line of defence against oil and gas spills since its development in the early 1900s. However, as drilling and exploration activities move further offshore, challenges pertaining to reliable operation of the subsea BOP systems continue to be a source of concern for stakeholders in the industry. In spite of recent advancements in reliability analysis of safety instrumented systems (SISs), the research on reliability assessment of BOP is still lacking in some regards. There are gaps in the literature with respect to the incorporation of preventive maintenance (PM) strategies as well as dynamic operating conditions into BOP reliability analysis. To address these gaps, this paper develops an advanced analysis method using stochastic Petri nets (SPN) to estimate the reliability of subsea BOP systems subject to condition-based maintenance (CBM) with different failure modes. The BOP system is divided into five subsystems which are connected in series with each other and categorised into degrading and binary units. The performance of the BOP system in terms of availability, reliability and mean-time-between failures (MTBF) is obtained and analysed. A sensitivity analysis is also performed to evaluate the effect of fault coverage factor and redundancy design on system performance. The results show that both the fault coverage factor and redundancy have significant impact on the BOP's reliability, availability and MTBF. 相似文献
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Runaway reactions by organic peroxides have occurred throughout the world. In this study, we used 1,1,-Di(tert-butylperoxy) cyclohexane (CH) 70 mass% as the main material, which was extensively employed as initiator for styrene in polymerization. Fire extinguishers are the first fire-fighting apparatus when fires occur. If a fire extinguisher has sat idle for a long time, which would cause the extinguishing agent to damp, it cannot achieve the desired effect and be properly handled at the start of the accident, thereby causing more casualties and property losses. CH 70 mass% was employed to mixed with monoammonium phosphate (MAP) for understanding the phenomenon by applying differential scanning calorimetry (DSC). Safety parameters also were carried out for more deeply understanding the basic characteristics for preventing an accident from occurring, in terms of applying CH 70 mass% as the initiator in the manufacturing process. 相似文献
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为降低强降雨导致建设工程安全事故发生率,有效解决该类安全事故人因分析复杂问题,提出新的安全事故人因分析模型方法。基于人为因素分析与分类系统(HFACS),建立包括 6层 24个因素的建设工程强降雨事故(CPHRA)框架模型(HC);联用遗传算法(GA)优化连续关联规则挖掘算法(CARMA)(GC)分析人为致因关联,绘制事故人为致因链;选取150起强降雨导致建设工程事故典型案例进行模型验证与应用分析。结果表明:优化后的人因分析HC-GC模型具有更优的性能与效率;在事故人因链中,政府安全主管部门监督不足与企业安全文化缺失是深层次因素,现场违规监管与现场安全管理漏洞是主要连接因素,技能水平低与失误违章会进一步强化事故负反馈,事故上报与响应不及时是强降雨导致建设工程事故扩大蔓延最直接原因。 相似文献
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为缓解非机动车用户违规骑行引发的道路交通安全问题,基于扩展计划行为理论(Ex-TPB),引入6个扩展潜变量,构建以违规骑行意向(VRI)为中介变量的非机动车用户事故倾向性(AP)结构方程模型(SEM);通过问卷调查采集变量数据,从社会心理学角度研究影响非机动车用户VRI和AP的心理因素。结果表明:该模型能解释违规骑行意向82.6%的变异,以及事故倾向性75.8%的变异;道德规范对违规骑行意向有显著负向影响,示范性规范、知觉行为控制、从众倾向、态度对违规骑行意向有显著正向影响,相应的影响程度依次减小;道德规范、示范性规范、知觉行为控制、态度不仅会直接影响事故倾向性,也通过违规骑行意向间接影响事故倾向性,且中介效应显著;从众倾向对事故倾向性的直接影响不显著,主要通过违规骑行意向间接影响事故倾向性。 相似文献
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为有效预防城市有轨电车相撞事故的发生,系统研究有轨电车相撞事故机制。针对有轨电车运行特点,利用刺激(S)-内部响应(O)-输出(R)模型将有轨电车司机处理危险过程分为感知、判断、操作3个阶段;分析每个阶段因差错引起的相撞事故演化过程,得出有轨电车相撞事故形成的3条途径;在有轨电车相撞事故物理模型的基础上,建立不同相撞事故形成途径下的有轨电车相撞事故模型。结果表明:任何一个阶段出现差错均会引起有轨电车相撞事故的发生,且感知差错引发相撞事故的可能性最大,判断差错引发相撞事故的可能性次之,操作差错引发相撞事故的可能性最小。 相似文献
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为减少因驾驶疲劳导致的交通安全事故,提出基于脑电(EEG)信号模糊熵(FE)的驾驶疲劳检测方法。开展在驾驶仿真模拟试验,采集28名被试模拟正常驾驶和疲劳驾驶的EEG信号;基于2种驾驶状态的EEG信号计算出FE值;运用随机森林(RF)、支持向量机(SVM)、决策树(DT)和K近邻(KNN)等4种分类器检测驾驶疲劳状态;利用多种性能指标及被试工作特征曲线(ROC)对驾驶疲劳检测结果进行分析比较。结果表明:基于疲劳驾驶状态下的EEG信号的FE值明显高于较正常驾驶状态下的值;4种分类器均可有效检测驾驶疲劳,其中K近邻的平均准确率达97.4%;基于EEG信号模糊熵的驾驶疲劳检测方法具有较好的鲁棒性和稳定性。 相似文献
20.
为规避偶氮二异丁酸二甲酯(AIBME)的潜在热危险,使用差示扫描量热仪(DSC)研究其热分解过程,并利用Kissinger法初步计算活化能;通过热安全软件(TSS)进行数据拟合,得到AIBME的活化能及相关动力学参数,与Kissinger法所得活化能进行比较;利用所得动力学参数建立热动力学模型,推算AIBME的自加速分解温度(SADT)和最大反应速率到达时间(TMRad)。研究结果表明:TSS进行分步式热分解分析所得AIBME的活化能比Kissinger法所得活化能更准确,所得第一阶段分解所需活化能为88.44 kJ/mol,第二阶段为113.87 kJ/mol;AIBME的SADT为30 ℃,在常温下可分解,故在生产、运输和储存过程中应加强温度的监控。 相似文献
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