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1.
The towed undulating vehicle (TUV), named SARAGO, was used for two fine-scale surveys between the Italian and the Sardinian coasts during the Astraea 2 cruise (6-7 and 26-27 September 1995), studying the deep chlorophyll maximum distribution. SARAGO sections identify a sub-surface doming with higher chlorophyll a and primary production concentrations in the upwelling area of a cyclonic gyre region, detected by sea-surface temperature images. In the first section, the cyclone presents a double doming, in density and salinity, with shallower and concentrated patches of chlorophyll a for about 2 miles. Twenty days later, the second section shows that the gyre changes shape and extension, showing a single doming with higher primary production and chlorophyll a concentrations, distributed over a large area of about 40 nautical miles. SARAGO allows analysis of this high-variability phenomenon (cyclonic gyre) and allows concentrated patches (2 nm) to be identified, thus proving the importance of TUVs in the study of mesoscale processes.  相似文献   
2.
Seat belt use habit has been investigated according to the education level of drivers. Copies of a questionnaire were distributed to 1000 participants of four different education levels. Factors such as seat belt usage habit, restricting factors and crash data have been investigated. Data have been analyzed with SPSS 15.0 software. Increased level of education leads to increased seat belt usage, lower numbers of crashes and crash severities. The factors restricting seat belt use are lack of habit, discomfort and short distance driving. The use of precaution signal and increases in comfort can increase seat belt usage. The primary and high school education on traffic safety and seat belt usage has been serving the purpose.  相似文献   
3.
填埋堆体表面形变监测是填埋场库容管理和堆体失稳等风险分析的核心,其时空高分辨率监测研究近年来引起广泛关注。基于航空摄影的地表测量技术具有采集速度快、时空分辨率高等优点,但在填埋场特殊环境下,面对高频填埋活动、显著的堆体变化以及防雨膜覆盖等干扰时,要同时满足高时空分辨率和耗时短的动态监测要求,无人机的最佳飞行参数设定亟待研究。为此,该研究模拟中等规模危险废物填埋场的规模和日填埋量,利用专业级无人机获取模拟区域图像,空三加密处理生成三维点云数据,利用Arcmap叠加分析多期监测数据,从点位坐标、重构尺度、重构体积、体积差分精度4个角度分析重构误差。结果表明:三维重构的坐标精度可以达到米级;重构尺度误差为2~3 cm,重构体积误差为0.16~0.17 m3,差分体积误差为0.16~0.17 m3;进一步研究发现,高度为25~55 m时,高度越高精度越低,相机倾角为[-53°,-60°]时,精度最高,旁向重叠率大于80%时,误差骤减且基本稳定。考虑到填埋场的填埋作业间隔、无人机续航能力等对飞行时间的约束,为获得最佳精度,建议无人机飞行高度为37 m、相机倾斜角度为[-53°,-60°]、旁向重叠率为80%。  相似文献   
4.
ABSTRACT: Two types of organizational systems provide most of the water service in the United States. The investor-owned firm operates on a profit basis generally subject to state commission regulation. The government-owned firm is generally confronted by local control. The comparative efficiency of private versus government firm provision of water services is essentially an empirical issue. Unit costs and other operating statistics are examined for water firms of each ownership form. The analysis shows that private firms tend to have higher operation costs than do government firms, possibly attributable to wage-salary differentials. The analysis also indicates that capital investment in large government firms may result in diseconomies. The analysis creates serious doubt as to whether efficient provision of water services can be better facilitated by large mergers of either ownership form.  相似文献   
5.
    
Objective: Road traffic suicides typically involve a passenger car driver crashing his or her vehicle into a heavy vehicle, because death is almost certain due to the large mass difference between these vehicles. For the same reason, heavy-vehicle drivers typically suffer minor injuries, if any, and have thus received little attention in the research literature. In this study, we focused on heavy-vehicle drivers who were involved as the second party in road suicides in Finland.

Methods: We analyzed 138 road suicides (2011–2016) involving a passenger car crashing into a heavy vehicle. We used in-depth road crash investigation data from the Finnish Crash Data Institute.

Results: The results showed that all but 2 crashes were head-on collisions. Almost 30% of truck drivers were injured, but only a few suffered serious injuries. More than a quarter reported sick leave following their crash. Injury insurance compensation to heavy-vehicle drivers was just above €9,000 on average. Material damage to heavy vehicles was significant, with average insurance compensation paid being €70,500. Three out of 4 truck drivers reported that drivers committing suicide acted abruptly and left them little opportunity for preventive action.

Conclusions: Suicides by crashing into heavy vehicles can have an impact on drivers’ well-being; however, it is difficult to see how heavy-vehicle drivers could avoid a suicide attempt involving their vehicle.  相似文献   

6.
    
Introduction: This study performed a path analysis to uncover the behavioral pathways (from contributing factors, pre-crash actions to injury severities) in bicycle-motor vehicle crashes. Method: The analysis investigated more than 7,000 bicycle-motor vehicle crashes in North Carolina between 2007 and 2014. Pre-crash actions discussed in this study are actions of cyclists and motorists prior to the event of a crash, including “bicyclist failed to yield,” “motorist failed to yield,” “bicyclist overtaking motorist,” and “motorist overtaking bicyclist.” Results: Model results show significant correlates of pre-crash actions and bicyclist injury severity. For example, young bicyclists (18 years old or younger) are 23.5% more likely to fail to yield to motor traffic prior to the event of a crash than elder bicyclists. The “bicyclist failed to yield” action is associated with increased bicyclist injury severity than other actions, as this behavior is associated with an increase of 5.88 percentage points in probability of a bicyclist being at least evidently injured. The path analysis can highlight contributing factors related to risky pre-crash actions that lead to severe injuries. For example, bicyclists traveling on regular vehicle travel lanes are found to be more likely to involve the “bicyclist failed to yield” action, which resulted in a total 44.38% (7.04% direct effect + 37.34% indirect effect) higher likelihood of evident or severe injuries. The path analysis can also identify factors (e.g., intersection) that are not directly but indirectly correlated with injury severity through pre-crash actions. Practical Applications: This study offers a methodological framework to quantify the behavioral pathways in bicycle-motor vehicle crashes. The findings are useful for cycling safety improvements from the perspective of bicyclist behavior, such as the educational program for cyclists.  相似文献   
7.
为降低行人在与运动型多功能车(SUV)碰撞事故中的损伤程度,从国家车辆事故深度调查体系(NAIS)中选取一例典型的事故案例,运用Madymo建立事故碰撞模型,并验证其有效性,在此基础上进行仿真试验,研究SUV车辆低速情况下,5%女性假人、50%和95%男性假人在前倾、下蹲、站立等3种应急姿态下的损伤情况。结果表明:前倾是很危险的应急姿态;下蹲和站立姿态对中等和高大身材行人是良好的自我保护措施;小身材行人在3种应急姿态下与SUV碰撞易受致命伤。  相似文献   
8.
为了解电池热失控引起的电动汽车自燃事故起因,降低事故发生率,统计梳理2020年新能源汽车起火事故概况,并基于动力电池失效机制和车辆运行数据,提出一种融合事故阶段安全参数关联分析、事故现场调查和全生命周期数据一致性分析的事故多维分析方法,采用该方法深入剖析一起电动汽车起火事故。研究结果表明:事故多维分析方法可通过探究事故车辆的损毁情况和运行数据的变化特征,分析从故障到事故的演变过程,溯源事故原因。  相似文献   
9.
通过车载实验,怠速法检测、简易工况法检测数据评价分析等方法,研究了重庆市在用CNG车辆排放情况,比较了CNG车与同类型汽油、柴油车尾气污染物排放情况。研究发现,目前CNG在用车并非绝对的环保汽车,其中在NOx的排放上,CNG车排放高于同类型汽油、柴油车0.03—14倍;在CO、THC的排放上,不同测试工况下CNG汽车表...  相似文献   
10.
Objectives: Nationally, animal–motor vehicle crashes (AVCs) account for 4.4% of all types of motor vehicle crashes (MVCs). AVCs are a safety risk for drivers and animals and many National Park Service (NPS) units (e.g., national park, national monument, or national parkway) have known AVC risk factors, including rural locations and substantial animal densities. We sought to describe conditions and circumstances involving AVCs to guide traffic and wildlife management for prevention of AVCs in select NPS units.

Methods: We conducted an analysis using NPS law enforcement MVC data. An MVC is a collision involving an in-transit motor vehicle that occurred or began on a public roadway. An AVC is characterized as a collision between a motor vehicle and an animal. A non-AVC is a crash between a motor vehicle and any object other than an animal or noncollision event (e.g., rollover crash). The final data for analysis included 54,068 records from 51 NPS units during 1990–2013. Counts and proportions were calculated for categorical variables and medians and ranges were calculated for continuous variables. We used Pearson’s chi-square to compare circumstances of AVCs and non-AVCs. Data were compiled at the park regional level; NPS parks are assigned to 1 of 7 regions based on the park’s location.

Results: AVCs accounted for 10.4% (5,643 of 54,068) of all MVCs from 51 NPS units. The Northeast (2,021 of 5,643; 35.8%) and Intermountain (1,180 of 5,643; 20.9%) regions had the largest percentage of the total AVC burden. November was the peak month for AVCs across all regions (881 of 5,643; 15.6%); however, seasonality varied by park geographic regions. The highest counts of AVCs were reported during fall for the National Capital, Northeast/Southeast, and Northeast regions; winter for the Southeast region; and summer for Intermountain and Pacific West regions.

Conclusions: AVCs represent a public health and wildlife safety concern for NPS units. AVCs in select NPS units were approximately 2-fold higher than the national percentage for AVCs. The peak season for AVCs varied by NPS region. Knowledge of region-specific seasonality patterns for AVCs can help NPS staff develop mitigation strategies for use primarily during peak AVC months. Improving AVC data collection might provide NPS with a more complete understanding of risk factors and seasonal trends for specific NPS units. By collecting information concerning the animal species hit, park managers can better understand the impacts of AVC to wildlife population health.  相似文献   

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