基于生理指标的建筑工人攀登作业疲劳实验研究

为研究攀登作业建筑工人生理疲劳状态的评测指标,提出1种基于生理指标的建筑工人攀登作业疲劳测度实验方法。首先,设计实验测量建筑工人的心率、皮肤温度、舒张压、收缩压4项生理指标,结合Brog’s RPE主观疲劳程度量表研究建筑工人生理疲劳的变化;其次,提取上述4项指标的平均值和标准差作为生理指标特征值,利用静息状态下生理指标特征值和疲劳状态下生理指标特征值进行方差分析、球形检验、T检验筛选出与疲劳相关的特征值;最后,利用支持向量机构建疲劳检测模型。研究结果表明：上述8项生理指标特征值与攀登作业工人疲劳具有显著相关性,疲劳检测模型的准确率为96.875%,研究结果可对攀登作业人员疲劳评估和疲劳预警具有实践性意义。     

Factors affecting the growth rates of ammonium and nitrite oxidizing bacteria

The maximum specific growth rates of both ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) were investigated under varying aerobic solids retention time (SRT_a) and in the presence/absence of anoxic (alternating) conditions. Two bench SBRs, reactor R1 and R2, were run in parallel for 150 d. Reactor R1 was operated in aerobic conditions while R2 operated in alternating anoxic/aerobic conditions. The feed (synthetic wastewater), temperature, hydraulic retention time and mixing were identical in both reactors. The SRT_a in both reactors was, sequentially, set at four values: 5, 4, 3 and 2 d.Kinetic tests with the biomasses from both reactors were carried out to estimate the maximum specific growth rates (μ_max) at each tested SRT_a and decay rates, in both aerobic and anoxic conditions. The kinetic parameters of nitrifier were estimated through the calibration of a two step nitrification-denitrification activated sludge model.The results point to a slightly higher μ_max,AOB and μ_max,NOB in alternating conditions, while both μ_max,AOB and μ_max,NOB were shown not to vary in the tested range of SRT_a (from 2 to 5 d) at 20 °C. They were relatively high when compared to literature data: 1.05 d⁻¹ < μ_max,AOB < 1.4 d⁻¹ and 0.91 d⁻¹ < μ_max,NOB < 1.31 d⁻¹. The decay coefficients of both AOB and NOB were much higher in aerobic (from 0.22 d⁻¹ to 0.28 d⁻¹) than in anoxic (0.04 d⁻¹ to 0.16 d⁻¹) conditions both in R1 and R2, which explained the higher nitrification rates observed in the alternating reactor.     

The effects of aging time on the fraction distribution and bioavailability of PAH

Understanding the effects of aging time on the fraction distribution and bioavailability of PAH, such as phenanthrene (PHE) and pyrene (PYR), has considerable benefits for risk assessment, food security and remediation strategies for contaminated soil. The results of the present study show that the proportion of the desorbed PHE decreased from ca. 82% at day 0 to ca. 65% at day 150. In addition, non-desorbed PHE increased from ca. 18% at day 0 to ca. 31% at day 150, whereas the changes of desorbed and non-desorbed PYR showed no significant trend during this aging period. The proportion of desorbed PYR was lower than that of PHE, whereas the opposite occurred with the non-desorbed fraction. After 150 d of aging, the proportion of bound residues (PHE and PYR) increased significantly with the cultivating time from ca. 0.2% to ca. 4.7% and ca. 0.1% to ca. 1.2% for PHE and PYR, respectively. In addition, the bioavailability of PAH (PHE and PYR) to earthworms was also assessed over 0-150 d. The results showed that the uptake rate and bioconcentration factor (BCF) of pollutants by earthworms displayed the following biphasic character: a rapid decrease over the first 15 d followed by a slow decrease over the next 135 d. Moreover, the earthworm uptake rate of PHE was greater than that of PYR throughout the incubation period, indicating that PHE has a higher bioavailability than PYR. In addition, the positive correlation between the uptake rate of earthworms and PAH extractability suggested that a three-step extraction is a reliable approach to predict PHE bioavailability in soil. However, a limit was observed for PYR.     

Teaching older drivers to navigate GPS technology

Background and objectives: New technologies are being implemented in motor vehicles. One key technology is the electronic navigation system (ENS) that assists the driver in wayfinding, or actually guides the vehicle in higher level automation vehicles. It is unclear how older adults interact with ENSs and the best approach to train older adults to use the devices. The objectives of this study were to explore how older drivers interacted with an ENS while driving on live roadways and how various training approaches impacted older drivers’ ability to accurately enter destinations into the ENS. Research design and methods: In Experiment 1, 80 older drivers navigated unfamiliar routes using an ENS or paper directions and completed a series of ENS destination entry tasks. In Experiment 2, 60 older drivers completed one of three training conditions (ENS video only, ENS video with hands-on training, placebo) to examine the impacts of training on destination entry performance. Results and discussion: Driving performance was aided by the use of the ENS, but many older drivers had difficulty entering destinations into the device (Experiment 1). The combined video with hands-on ENS training resulted in the best overall destination entry performance (Experiment 2). Practical applications: The results suggest older drivers may experience problems entering destinations into ENSs, but training can improve performance. These performance issues may be especially important as more vehicle features require interaction with computer systems to select destinations or other automation related features. Further research is needed to determine how to prepare the next generation of older drivers who will interact with technologies aimed at increasing mobility.     

An integrated methodology to manage risk factors of aging urban oil and gas pipelines

Aging urban oil and gas pipelines have a high failure probability due to their structural degradation and external interference. The operational safety of the aging urban oil and gas pipeline is challenged by different hazards. This paper proposes a novel methodology by integrating an index-based risk evaluation system and fuzzy TOPSIS model for risk management of aging urban oil and gas pipelines, and it is carried out by evaluating the priority of hazards affecting pipeline safety. Firstly, the hazard factors of aging urban oil and gas pipelines are identified to establish an index-based risk evaluation system. Subsequently, the fuzzy TOPSIS model is employed to evaluate the importance of these hazard factors and to decide which factors should be managed with priority. This work measures the importance of a hazard factor from three aspects, i.e. occurrence (O), severity (S) and detectability (D), and the weights of these three parameters are determined by a combination weight method. Eventually, the proposed methodology is tested by an industrial case to illustrate its effectiveness, and some safety strategies to reduce the operational risk of the pipeline are presented. The proposed methodology is a useful tool to implement more efficient risk management of aging urban oil and gas pipelines.     

Guidance to improve the effectiveness of process safety management systems in operating facilities

The Process Safety Management (PSM) systems at the operating facilities in the Oil & Gas and in Chemical manufacturing industries have matured over the years and have become, at most facilities, very robust and sophisticated. These programs are administrated by Process Safety (PS) teams at both the corporate business units and plant levels and have been effective in reducing the number and severity of PS events across the industries over the past 25 years or so. Incidents however are occurring at a regular interval and in recent times several noteworthy PS events have occurred in the United States which have brought into question the effectiveness of the PSM programs at play. These facilities have been applying their PSM programs with the expectation that the number and severity of PS events would decrease over time. The expected result has not been realized, especially in context to those facilities that have undergone the recent incidents. Current paper reviews a few publicly available PS performance reports of Oil & Gas and Chemical manufacturing industries. The authors identified a few factors at play that have led to these PS events based on their experience, literature review, and incident investigation reports. Most of the factors are intertwined with multiple PSM elements and it requires a holistic approach to address them. Each of the factors is described and the path forward is proposed to improve the effectiveness of PSM programs.     

基于社会网络分析的建筑工人不安全行为传播路径研究

为提升建筑施工安全管理水平,基于群体视角分析班组中建筑工人间不安全行为传播路径特点,运用社会网络分析理论构建建筑施工班组成员间不安全行为网络传播模型。以1个钢筋工班组为例,通过问卷调查获得样本数据,对得到的网络模型中网络密度、网络中心势、凝聚力、中心性、核心 边缘结构以及凝聚子群等指标进行量化分析。研究结果表明:建筑工人构成的不安全行为传播网络密度较高,凝聚力较强,不安全行为传播明显;技术工人作为行为领袖处于网络核心位置上,人缘较好的工人处于次级核心位置,班组长以及新工人处于班组边缘位置;不安全行为经由核心处中间人传播到其他工人;班组中存在明显的子群结构。     

某地区铁路职工高尿酸血症检出情况及影响因素分析

为了解某地区铁路职工高尿酸血症的检出情况及影响因素,以2019年该地区铁路职工21 578名体检人员为研究对象,分析该人群中高尿酸血症的检出情况,研究年龄、性别、体质指数(BMI)、血压、血脂、空腹血糖、尿pH对高尿酸血症的影响.结果表明,高尿酸血症总检出率为22.4％,其中男性检出率(24.4％)高于女性;＜30岁和...     

Commercial trials evaluating the novel use of ethyl formate for in-transit fumigation of shipping containers

Sediment samples from 25 sites in 17 rivers of the Pantanal (Brazil) were analyzed with the objective of evaluating pesticide contamination in sediments. Samples were extracted with an acetone, ethylacetate, and water mixture 2:2:1 (v/v/v). The extract was purified by flash chromatography with aluminum oxide and florisil. A multiresidue gas chromatography-mass spectrometry method was applied to monitor 23 pesticides of different chemical classes (organochlorine, organophosphorus, triazines, anilides and pyrethroids) with some of their degradation products. Compounds identified in sediment samples included λ -cyhalothrin (1.0 to 5.0 μ g kg^{? 1}), p,p′-DDT (3.6 μ g kg^{? 1}), deltamethrin (20.0 μ g kg^{? 1}) and permethrin (1.0 to 7.0 μ g kg^{? 1}).