Physiological signal analysis for fatigue level of experienced and inexperienced drivers

Objective: We studied the changes in driving fatigue levels of experienced and inexperienced drivers at 3 periods of the day: 9:00 a.m.–12:00 p.m., 12:00 p.m.–2:00 p.m., and 4:00 p.m.–6:00 p.m.

Methods: Thirty drivers were involved in 120-min real-car driving, and sleepiness ratings (Stanford Sleepiness Scale, SSS; Hoddes et al. 1973 Hoddes E, Zarcone V, Smythe H, Phillips R, Dement WC. Quantification of sleepiness: a new approach. Psychophysiology. 1973;10:431–436.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), electroencephalogram (EEG) signals, and heart rates (HRs) were recorded. Together with principal component analysis, the relationship between EEG signals and HR was explored and used to determine a comprehensive indicator of driving fatigue. Then the comprehensive indicator was assessed via paired t test.

Results: Experienced and inexperienced drivers behaved significantly differently in terms of subjective fatigue during preliminary trials. At the beginning of trials and after termination, subjective fatigue level was aggravated with prolonged continuous driving. Moreover, we discussed the changing rules of EEG signals and HR and found that with prolonged time, the ratios of δ and β waves significantly declined, whereas that of the θ wave significantly rose. The ratio of (α + θ)/β significantly rose both before trials and after termination, but HR dropped significantly. However, one-factor analysis of variance shows that driving experience significantly affects the θ wave, (α + θ)/β ratio, and HR.

Conclusions: We found that in a monotonous road environment, fatigue symptoms occurred in inexperienced drivers and experienced drivers after about 60 and 80 min of continuous driving, respectively. Therefore, as for drivers with different experiences, restriction on continuous driving time would avoid fatigued driving and thereby eliminate traffic accidents. We find that the comprehensive indicator changes significantly with fatigue level. The integration of different indicators improves the recognition accuracy of different driving fatigue levels.     

热解温度对生物炭强化镉污染土壤治理的影响

为了探究污泥生物炭对Cd污染土壤的钝化修复效果,采用人工模拟Cd污染土壤进行盆栽实验,并探究了生物炭对Cd污染土壤pH、有机碳、Cd含量及价态、玉米株高、富集系数及生物转化系数的影响。结果表明:热解温度为800℃时制备的生物炭的修复效果优于300℃时制备的生物炭,且生物炭的最佳剂量为9.0 g/kg。施用800℃下制备的生物炭时,土壤中Cd含量也增加至7.9 mg/kg,较热解温度300℃增加约1.0 mg/kg。污泥生物炭显著降低了土壤中酸可提取态及还原态Cd的含量,升高了氧化态及残渣态Cd含量。当热解温度为800℃时,酸可提取态和还原态Cd含量分别降低至0.68,0.45 mg/kg,氧化态及残渣态Cd含量分别升高至0.76,1.72 mg/kg,从而降低了土壤中可生物利用Cd的含量。此外,生物炭能够降低Cd的生物富集系数及转化系数。     

Environmental impact and health risk assessment of volatile organic compound emissions during different seasons in Beijing

Volatile organic compounds (VOCs) are major contributors to air pollution. Based on the emission characteristics of 99 VOCs that daily measured at 10 am in winter from 15 December 2015 to 17 January 2016 and in summer from 21 July to 25 August 2016 in Beijing, the environmental impact and health risk of VOC were assessed. In the winter polluted days, the secondary organic aerosol formation potential (SOAP) of VOC (199.70 ± 15.05 μg/m³) was significantly higher than that on other days. And aromatics were the primary contributor (98.03%) to the SOAP during the observation period. Additionally, the result of the ozone formation potential (OFP) showed that ethylene contributed the most to OFP in winter (26.00% and 27.64% on the normal and polluted days). In summer, however, acetaldehyde was the primary contributor to OFP (22.00% and 21.61% on the normal and polluted days). Simultaneously, study showed that hazard ratios and lifetime cancer risk values of acrolein, chloroform, benzene, 1,2-dichloroethane, acetaldehyde and 1,3-butadiene exceeded the thresholds established by USEPA, thereby presenting a health risk to the residents. Besides, the ratio of toluene-to-benzene indicated that vehicle exhausts were the main source of VOC pollution in Beijing. The ratio of m-/p-xylene-to-ethylbenzene demonstrated that there were more prominent atmospheric photochemical reactions in summer than that in winter. Finally, according to the potential source contribution function (PSCF) results, compared with local pollution sources, the spread of pollution from long-distance VOCs had a greater impact on Beijing.     

洪家渡、东风电站在梯级开发中的环境经济发展影响

乌江是长江上游四大支流之一,水量丰富,流量均衡,平均比降大,是我国水能资源的一个“富矿”地区。从６０年代末开始,国家在流域内规划建设１１个梯级电站,其中的洪家渡、东风电站是乌江干流梯级开发中的龙头电站,其环境经济状况及成效将对其他库站产生较大的影响。为此,本文重点从其环境经济发展方面作有关的相关效应评述。     

水合二氧化锰界面特性及其除污染效能

研究了水合二氧化锰(δMnO2)的界面特性及其吸附性能.考察了δMnO2的比表面积、粒径分布、表面官能团及ζ电位;探讨了δMnO2对水中亚砷酸盐及腐殖酸的吸附去除效能.结果表明:δMnO2的比表面积为117.4m2·g-1,体积平均粒径为0.11μm;δMnO2表面具有丰富的表面羟基(Mn-OH);随着pH值由1.9升高至10.7,δMnO2的ζ电位由 22.7mV降低至53.5mV,其零电荷点在pH3.0附近.δMnO2对亚砷酸盐(As(III))及腐殖酸(HA)均表现出优良的吸附去除效能,其单位δMnO2质量的最大吸附量分别为137μgAs(III)·mg-1δMnO2和1.01mgTOC·mg-1δMnO2.亚砷酸盐与腐殖酸共存时,腐殖酸的存在使得亚砷酸盐的去除率下降10%—28%;而亚砷酸盐对腐殖酸的去除无明显影响.     

湖南主要农田土壤中氮的形态

本试验采集了湖南省八种主要母质发育的２３个农田土壤耕层样本，其中水田土壤１６个，旱地土壤７个．将土壤氮分为七级．即交换性ＮＨ４＋十ＮＯ３－，水解性ＮＨ４＋，氨基糖氮，可溶性碱稳定态氮，酸溶性腐殖质态氮，固定态ＮＨ４＋，难溶性腐殖质态氮。分析结果表明，土壤中交换性ＮＨ４＋十ＮＯ３－的含量为２２．０土９．０ｍｇ／ｋｇ，占全氮的１．７土０．７％；水解性ＮＨ４＋为３２４．４土１０９．５ｍｇ／ｋｇ，占全氮的２３．９±５．６％；氨基糖氮为１１８．９土４３．０ｍｇ／ｋｇ，占全氮的９．１土３．２％；可溶性碱稳定态氮为４９７．１土２０５．８ｍｇ／ｋｇ，占全氮的３６．２土８．３％；酸溶性腐殖质态氮为２９．２土１０．２ｍｇ／ｋｇ，占全氮的１３土０．８％；固定态ＮＨ４＋为４７．２土２４．３ｍｇ／ｋｇ，占全氮的３．６±１．７％；难溶性腐殖质态氮为３４１．３土２７０．８ｍｇ／ｋｇ，占全氮的２２．２土１１．６％。     

海口市绿地对空气含菌量影响的生态效应

采用平皿自然沉降方法,选择海口市区主要交通干道、公园、居民区的主要不同类型的绿地,测定空气微生物的含量。绿地、对照地的平均含菌量分别5 203.4 CFU/m37、182.7 CFU/m3。对其进行t-检验,表明绿地能够减少空气含菌数量。此外,绿地的覆盖率、植物种类也是影响绿地降低气挟菌数量效应的重要因素。     

Alkanes and hopanes for pollution source apportionment in coking plant soils

Polluted soils of former coking plants are characterized by multiple organic contributions, e.g. coal tar, coal, coke, soot, and natural organic matter, that can either be sources of polycyclic aromatic hydrocarbons (PAHs) or act as sorption surfaces for pollutants. The contamination level is usually based on the quantification of 16 PAHs but it does not provide any information on PAH sources. We studied the aliphatic fractions of 25 soil samples from a former coking plant site by microscopy and gas chromatography-mass spectrometry (GC-MS). The microscopic investigation allowed to identify four main organic contributions: coal tar, coal, coke, and natural organic matter. These isolated sources were analyzed and considered as reference materials. Although the PAH distributions were very similar in the 25 contaminated soils, alkanes and hopanes distributions were representative from various contributions characterizing the relative enrichment in coal, coal tars, or natural organic matter. Two principal component analyses based on n-alkanes and hopanes showed that three molecular indices, the carbon preference index, the low molecular weight/high molecular weight n-alkanes ratio, and the 18α(H)-22,29,30-trisnorhopane/(18α(H)-22,29,30-trisnorhopane+17α(H)-22,29,30-trisnorhopane) ratio allow to classify polluted soils according to various organic contributions.     

Serum PCDD/F concentration distribution in residents living in the vicinity of an incinerator and its association with predicted ambient dioxin exposure

The aim of this study was to evaluate the serum polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentration distribution in residents living in the vicinity of an incinerator and its association with annual ambient dioxin exposure predicted by an atmospheric dispersion model. A municipal waste incinerator in Northern Taiwan was chosen for this study. This incinerator had been in operation for 6 years at the time of this study. Using the incinerator site as the center, based on the simulated ambient annual average PCDD/F concentrations. Ninety-five volunteers, all live within a radius of 5 km from the incinerator for at least 5 years, who had no occupational exposure potential, were selected based on the population distribution in each district. The average serum PCDD/F concentration for these subjects living within four zones was about 14 pg I-TEQ/g lipid. The serum distribution levels of people of the four study zones, however, were not consistent with the predicted ambient levels. Results also suggest that ambient exposure might not be the most important contributor to serum concentrations when compared to other exposure sources, such as dietary intake.     

活性炭纤维净化印刷过程产生的VOCs废气

介绍了应用局部排气的方法,收集印刷过程的挥发性有机化合物(VOCs)废气,应用活性炭纤维(ACF)吸附脱附有机废气回收净化装置,进行印刷厂VOCs废气的回收与治理,详细描述了印刷车间VOCs废气的收集与处理工艺过程及其效果.测试结果表明,应用此工艺和设备可以有效地进行印刷过程大风量的VOCs废气的回收和治理.