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71.
72.
Spatial gradients and source apportionment of volatile organic compounds near roadways 总被引:1,自引:0,他引:1
David A. Olson Davyda M. Hammond Robert L. Seila Janet M. Burke Gary A. Norris 《Atmospheric environment (Oxford, England : 1994)》2009,43(35):5647-5653
Concentrations of 55 volatile organic compounds (VOCs) (C2–C12) are reported near a highway in Raleigh, NC. Thirty-minute samples were collected at eight locations, ranging from approximately 10–100 m perpendicular from the roadway. The highest concentrations of VOCs were generally measured closest to the roadway, and concentrations decreased exponentially with increasing distance from the roadway. The highest mean concentration for individual VOCs were for ethylene (3.10 ppbv) (mean concentration at x = 13 m), propane (2.27 ppbv), ethane (1.91 ppbv), isopentane (1.54 ppbv), toluene (0.95 ppbv), and n-butane (0.89 ppbv). Concentrations at the nearest roadway location (x = 13 m) were generally between 2.0 and 1.5 times those from the farthest roadway location (x = 92 m). The data were apportioned into four source categories using the EPA Chemical Mass Balance Model (CMB8.2): motor vehicle exhaust, compressed natural gas, propane gas, and evaporative gasoline. The majority of the VOCs resulted from motor vehicle exhaust (67 ± 12%) (% of total VOC at x = 13 m ± S.D.). Compressed natural gas, propane gas, and evaporative gasoline accounted for approximately 15%, 7% and 1% of the total VOC emissions, respectively, at x = 13 m. 相似文献
73.
Mana Sangkapichai 《Journal of Environmental Planning and Management》2009,52(1):79-96
This paper explores quantitatively Californians' interest in hybrid electric vehicles (HEV) based on a statewide phone survey conducted in July 2004 by the Public Policy Institute of California. The paper develops ordered choice models and factors that summarise beliefs about energy and the environment using principal component analysis. As expected, Californians concerned about the environment, energy efficiency, global warming and recent increases in the price of gasoline state a higher interest in hybrids; an even more important reason for considering hybrid electric vehicles, however, is the possibility of using high occupancy vehicle (HOV) lanes while driving alone, especially for people with potentially long commutes to work. The findings also suggest that beliefs about energy and the environment should be included in vehicle type choice models. 相似文献
74.
电焊熔珠对棉布和聚氨酯泡沫的引燃能力研究 总被引:1,自引:0,他引:1
研究了加载电压对电焊熔珠数目和粒径分布的影响,在模拟装置上实验了电焊对棉布、聚氨酯泡沫和纸张的引燃性能.结果表明,随着加载电压升高,电焊熔珠的数目逐渐减少,熔珠粒径逐渐增大,引燃能力逐渐增强.固体材料性质对电焊熔珠引燃能力也有很大影响,表面粗糙,易蓄热材料容易被点燃.电焊熔珠引燃棉布、聚氨酯泡沫和纸张的临界电压为37.5V、40V和45V. 相似文献
75.
Fayard GM 《Journal of Safety Research》2008,39(1):9-18
PROBLEM: Although parking facilities are a common feature of the landscape in the United States, little is known about their safety. METHOD: A dataset of parking lot fatalities for 1993-2002, created from the Census of Fatal Occupational Injury (CFOI) research file, was analyzed. RESULTS: The most common events in parking lots were contact with objects (15%), pedestrian fatalities (13%), homicides (36%), and suicides (11%). The perpetrators of parking lot fatalities, compared to all workplace homicides, were more likely to be known to the victim. CONCLUSION: The 206 work-related fatalities per year in parking lots present challenges to the safety community. Although much of the risk results from the usage of motor vehicles, violent acts are even more prominent. IMPACT ON INDUSTRY: Because homicides are most prevalent in parking lots, both administrative and environmental measures may lower the risk of homicide. Although difficult to assess, various elements of the design of parking facilities may have an influence on the occurrence of injuries. 相似文献
76.
Sandy beaches are the prime sites for human recreation and underpin many coastal economies and developments. In many coastal
areas worldwide, beach recreation relies on the use of off-road vehicles (ORVs) driven on the shore. Yet, the use of ORVs
is not universally embraced due to social conflicts with other beach user groups and putative environmental consequences of
vehicle traffic on sandy shores. Such ecological impacts of ORVs are, however, poorly understood for endobenthic invertebrates
of the intertidal zone seawards of the dunes. Consequently, this study quantified the degree to which assemblages of intertidal
beach invertebrates are affected by traffic. The study design comprised a series of temporally replicated spatial contrasts
between two reference sites (no ORVs) and two beaches with heavy ORV traffic (in excess of 250,000 vehicles per year) located
in South-East Queensland, Australia. Macrobenthic assemblages on ORV-impacted beaches had significantly fewer species at substantially
reduced densities, resulting in marked shifts in community composition and structure. These shifts were particularly strong
on the middle and upper shore where vehicle traffic was concentrated. Strong effects of ORVs were detectable in all seasons,
but increased towards the summer months as a result of heavier traffic volumes. This study provides clear evidence that ORVs
can have substantial impacts on sandy beach invertebrates that are manifested throughout the whole community. Demonstrating
such an ecological impact caused by a single type of human use poses a formidable challenge to management, which needs to
develop multi-faceted approaches to balance environmental, social, cultural, and economic arguments in the use of sandy shores,
including management of “beach traffic.” 相似文献
77.
在分析城市步行街及其周边存在人车混行、人员密度高、通行效率低、潜在的危险大的基础上,笔者用计算机模拟方法研究了沈阳市中街步行街的一个人车混行的交叉路口,实际勘察了十字路口道路格局、车流、人流状况,测量、估计通过路口的人数、流量,根据获得的数据,对不设置交通信号灯、设置信号灯、建设过街天桥或地下通道等几种情况进行模拟,得到各种情况下的通行效率,并对不同的过街方案的优缺点进行比较。最终选择过街方案需要综合考虑影响安全和效率的多种因素,包括地域、人流量、路口宽度、周边交通等因素,用较小的经济投入取得最大的通行效率。文中的模拟采用EXODUS软件。 相似文献
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