南非HS抑爆系统性能的试验研究

为了验证南非HS抑爆系统的安全性能,对HS系统进行基本性能试验和系统的整机抑爆效果试验。该系统的喷洒滞后时间、成雾时间、有效雾面持续时间和喷洒率4个基本参数的性能进行了测量和计算。在HS系统的整机抑爆效果试验中,进行4次不同的试验。试验结果表明,HS系统能迅速地产生具有足够的面积和持续时间的喷雾屏障,有效地抑止瓦斯和煤尘的燃烧与爆炸。HS系统具有较好的安全性能和较为广阔的应用前景。     

北武夷地区前寒武系变质岩地球化学特征

通过对北武夷地区前寒武系变质岩的岩石化学、稀土元素及微量元素等综合研究 ,从中元古代铁沙街岩组、周潭岩组到晚震旦世至早寒武世万源组、洪山组、外管坑组 ,SiO2 、K2 O、K2 O/Na2 O等具有逐渐增大的趋势 ,而TiO2 、Al2 O3 、FeO、MgO、Na2 O及SiO2 /Al2 O3 则逐渐减小 ;ΣLREE/ΣHREE增加 ,而ΣREE总体具减小趋势 ;Sc、Ba、Rb、Cu、Cr等微量元素含量增大 ,而Ni、Th、U、Ta、Nb、Ga、Zr、Hf、V、Zn、Co等则减少。本文利用地球化学参数判别本区前寒武系岩石形成构造环境为被动大陆边缘。     

深圳市大气中全氟化合物的残留特征

为探究深圳市大气中全氟化合物(perfluorinated compounds,PFCs)的残留特征,基于负载XAD-4的PUF膜被动采样器采集了2014年11月1日至2015年1月31日深圳市12个位点的大气样品,分析了大气中7种挥发性PFCs和15种离子型PFCs的含量及分布特征.结果表明,深圳市大气中ΣPFCs平均浓度为79.0 pg·m-3(23.7~157 pg·m-3),以挥发性PFCs为主.8∶2氟调聚醇(fluorotelomer alcohol,FTOH)、6∶2 FTOH和全氟戊酸(perfluoropentanoic acid,PFPe A)、全氟辛酸(perfluorooctane acid,PFOA)分别是挥发性和离子型PFCs的主要组分.深圳市大气中挥发性和离子型PFCs的空间分布相同,均呈西北高东南低的态势.此外,6∶2 FTOHs、8∶2 FTOHs、PFPe A、PFHx A和PFOA与PM_(2.5)、PM_(10)呈正相关(P0.05,P0.01),而与PM_(10)的相关性更显著.     

不同休息方式对缓解监控作业疲劳的作用研究

为探讨消极休息与积极休息对缓解监控作业疲劳的作用,在分析监控作业特点基础上,利用计算机语言编程模拟监控作业,设计两个主实验分别从主观评价及生理心理指标测量等方面对被试者在采用不同方式休息前后的疲劳指标进行测量,并对数据进行差异性分析。实验数据分析结果表明:日常工作和生活中大家较多采用的消极休息方式能够在有限时间内较好缓解监控作业疲劳,以小强度运动为主的积极休息方式也能够较好地起到缓解监控作业疲劳的效果。但经过同样时间、同样强度的监控作业后,在相同短的休息时间内,采用积极休息方式比采用消极休息方式对于缓解监控作业疲劳更有效。     

Field Evaluation of the PAS III Passive Alcohol Sensor

Passive alcohol sensors (PAS) are screening devices designed to sample nonintrusively the ambient air around a driver's mouth to determine the presence of alcohol. Studies have shown that PAS devices can aid police officers in the identification of unpaired drivers, particularly at sobriety checkpoints. Data from a 1996 nationwide survey, in which 5,392 drivers were evaluated for alcohol using both the PAS III (a passive sensor housed in a flashlight) and evidential breath test devices, have allowed the determination of appropriate criteria at various blood alcohol concentrations (BAC) for detecting impaired drivers in the field. Using the appropriate criteria, the PAS III can identify about 75% of the drivers with BACs at or above 0.10%, and 70% at or above 0.08%. This is a vast improvement over the 40-50% detection rate currently achieved by police officers at checkpoints not using sensors. Using the PAS III few drivers would be identified inappropriately. At the criterion recommended for detecting BACs at or above 0.08%, about 14% of drivers with BACs of 0.02-0.05% would be incorrectly identified as having a higher BAC. Field studies have shown that when police officers rely on observation alone about 20% of drivers with low BACs are detained for further evaluation. More widespread use of passive sensors by police officers would aid in the detection of drinking drivers. Sensors also could provide an additional deterrent to the general public if they believe that when stopped by the police after drinking they will be detained for further evaluation.     

POCIS采样技术应用于九龙江流域水环境中雌激素的检测

极性有机物一体化采样器(POCIS)作为富集水体中有机物的新型采样技术,可以反映目标物在被测水体中的时间权重浓度,因此在环境监测中是对主动采样方式的重要补充.本研究采用POCIS进行了4种固醇类雌激素化合物(雌酮、雌二醇、雌三醇及雌炔醇)的富集动力学,以及温度和目标物浓度对POCIS富集雌激素影响的实验室模拟研究.结果表明,POCIS对目标化合物的富集放置时间7 d内呈现显著的线性关系(r2≥0.988 1,P<0.001).温度对目标物在POCIS上富集的影响比较显著(RSD>12%),随着温度的升高,目标化合物在POCIS上的采样速率减小.而目标物浓度对POCIS富集没有显著的影响(RSD<5%).将所建立的POCIS采样装置应用于九龙江流域的现场环境中,发现利用POCIS估算出的目标物时间权重浓度与主动采样测定的浓度具有显著的相关性(r2=0.720 9,P<0.001),验证了POCIS在实际环境中的可应用性.     

被动采集大气颗粒物样品的粒径分布特征

在可同时采集气态与颗粒态大气污染物的被动采样装置中放置涂有薄层凡士林的载玻片,用于采集大气悬浮颗粒物,利用粒度粒形仪分析样品粒径分布特征,并深入探讨风速以及采样罐外壁添加300目滤网(孔径50μm)对样品粒径分布的影响.结果表明,在室内静风与室外相对封闭的条件下,添加滤网可有效阻止50μm的粗颗粒组分进入采样罐;而在室外有风的条件下,添加滤网后仍有粗颗粒进入采样罐中,但进入概率与风速大小之间无关.观察粒径10μm以下颗粒的分布曲线,室内静风条件下得到的分布曲线与主动采样得到的结果极为类似.而在有风条件下,3～5μm的颗粒组分比重有所减少,6～9μm颗粒组分比重明显增加.上述问题在被动采样器的使用中需予以考虑,结合样点具体情况判断是否添加滤网.     

硅胶腕带被动采集多环芳烃的可行性分析

多环芳烃（polycyclic aromatic hydrocarbons,PAHs）对人体危害巨大,目前关于人体暴露于大气环境PAHs研究主要以主动采样方式开展。硅胶腕带作为一种新的大气被动采样装置,具有体积小、价格低、耐磨耐热、无毒无味等优点,适合人体环境暴露监测。国际上研究刚起步,尚未建立完善的腕带被动采样与主动采样技术之间的定量关系。本研究于2019年秋冬季和2021年冬季在西安市城区,同时开展硅胶腕带被动采样与大气主动采样对低分子量（MW＜203 g·mol^?1）PAHs的对比实验,力求建立两者的联系。2019年和2021年西安冬季大气中低分子量PAHs浓度分别为(52.81±14.76) ng·m^?3和(134.59±39.48) ng·m^?3,与前人研究相当。相对应的腕带浓度为(183.07±40.43) ng·d^?1和(524.99±150.32) ng·d^?1。Pearson相关分析发现：萘、苊烯、1-甲基萘、2-甲基萘、荧蒽以及总PAHs的主、被动采样之间显著相关（P＜0.05）,相关系数均大于0.4,证明硅胶腕带被动采样方法适用于低分子量PAHs的人体暴露监测。     

Assessment of ambient air quality in Eskişehir, Turkey

This paper presents an assessment of air quality of the city Eskişehir, located 230 km southwest to the capital of Turkey. Only five of the major air pollutants, most studied worldwide and available for the region, were considered for the assessment. Available sulphur dioxide (SO₂), particulate matter (PM), nitrogen dioxide (NO₂), ozone (O₃), and non-methane volatile organic carbons (NMVOCs) data from local emission inventory studies provided relative source contributions of the selected pollutants to the region.The contributions of these typical pollution parameters, selected for characterizing such an urban atmosphere, were compared with the data established for other cities in the nation and world countries. Additionally, regional ambient SO₂ and PM concentrations, determined by semi-automatic monitoring at two sites, were gathered from the National Ambient Air Monitoring Network (NAAMN). Regional data for ambient NO₂ (as a precursor of ozone as VOCs) and ozone concentrations, through the application of the passive sampling method, were provided by the still ongoing local air quality monitoring studies conducted at six different sites, as representatives of either the traffic-dense-, or coal/natural gas burning residential-, or industrial/rural-localities of the city. Passively sampled ozone data at a single rural site were also verified with the data from a continuous automatic ozone monitoring system located at that site. Effects of variations in seasonal-activities, newly established railway system, and switching to natural gas usage on the temporal changes of air quality were all considered for the assessment. Based on the comparisons with the national [AQCR (Air Quality Control Regulation). Ministry of Environment (MOE), Ankara. Official Newspaper 19269; 1986.] and a number of international [WHO (World Health Organization). Guidelines for Air Quality. Geneva; 2000. Downloaded in January 2006, website: http://www.who.int/peh/; EU (European Union). Council Directive 1999/30/EC relating to limit values for sulfur dioxide, nitrogen dioxide and lead in ambient air. Of J Eur Communities L 163: 14–30; 29.6.1999; EU (European Union). Council Directive 2002/3/EC relating to ozone in ambient air. Of J Eur Communities. L 67: 14–30; 9.3.2002.; USEPA (U.S. Environmental Protection Agency). National Ambient Air Quality Standards (NAAQS). Downloaded in January 2006, website: http://www.epa.gov/ttn/naaqs/] ambient air standards, among all the pollutants studied, only the annual average SO₂ concentration was found to exceed one specific limit value (EU limit for protection of the ecosystem). A part of the data (VOC/NO_x ratio), for determining the effects of photochemical interactions, indicated that VOC-limited regime was prevailing throughout the city.     

Solar tracking system – a review

The generation of power from the reduction of fossil fuels is the biggest challenge for the next half century. The idea of converting solar energy into electrical energy using photovoltaic panels holds its place in the front row compared to other renewable sources. But the continuous change in the relative angle of the sun with reference to the earth reduces the watts delivered by solar panel. In this context solar tracking system is the best alternative to increase the efficiency of the photovoltaic panel. Solar trackers move the payload towards the sun throughout the day. In this paper different types of tracking systems are reviewed and their pros and cons are discussed in detail. The results presented in this review confirm that the azimuth and altitude dual axis tracking system is more efficient compared to other tracking systems. However in cost and flexibility point of view single axis tracking system is more feasible than dual axis tracking system.