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《现代隧道技术》2018,(6)
灯具的配光曲线和布灯方式影响着灯具利用系数,而灯具利用系数又影响灯具功率和路面照度,进而影响照明系统的功耗和路面照明效果。为此,文章建立了基于灯具配光曲线和布灯参数的隧道照明利用系数计算模型,选择了4种配光曲线,对每种配光曲线均采用中央布灯、拱顶侧偏布灯、对称布灯和交错布灯4种常用布灯方式进行优化和仿真,对隧道中间段的配光曲线和布灯方式的节能性和照明效果进行了研究。研究结果表明:对称布灯是最节能且照明效果最好的布灯方式;中央布灯方式的照明效果仅次于对称布灯方式;除了特殊形状的配光曲线,交错布灯方式功耗最大,照明效果最差;沿隧道横向的配光曲线是尖顶水滴状较好,适用于除交错以外的3种布灯方式;沿隧道纵向的配光曲线最好是对称蝶形分布曲线,适用于4种布灯方式;横向配光曲线是尖顶水滴状,纵向配光曲线是对称蝶形分布曲线时,适用于4种布灯方式,且都有较好的节能性和照明效果;对称倾斜式配光曲线,其倾斜配光剖面最好与隧道横向一致,适用于对称和拱顶侧偏两种布灯方式。 相似文献
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在公路隧道照明中,不当的灯具配置将会导致令人眼不适的眩光,良好的隧道照明系统设计不仅需要提供足够的路面亮度和合适的亮度均匀度,还应尽量降低灯具产生的眩光对驾驶员行车的影响程度,提高安全性和舒适性.为此,本文运用照明分析软件DIALux4.13对公路隧道照明系统的常用眩光指标——阈值增量TI进行相关数值模拟,选取两种对称配光曲线,在较高的灯具总光通量(9000 lm)一定时,探究并分析双车道(8~10 m布灯间距、灯具发光面法向角度25°)和三车道(6 m布灯间距、灯具发光面法向角度35°)下的各车道阈值增量TI.研究结果得出,所有工况均表现出较低甚至为0的阈值增量TI值,满足相关规范规定的不大于15%的要求,不会对驾驶过程中的人眼造成不舒适的眩光感受. 相似文献
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公路隧道照明中相比中间段基本照明而言,加强照明采用传统宽光曲线照明的性价比并不高,较长照射路径反而易造成过多的光通量损耗。为此,本文采用数值模拟的方法对隧道加强照明进行仿真,对比收光型和非收(宽)光型两种配光曲线的照明计算结果,分析收光曲线的照明效能并进一步优化配置。研究结论为:加强照明收光型配光曲线比非收光型配光曲线更节能,当路面平均照度要求为1 500 lx时,非收光曲线照明需求光通量高出收光曲线照明15.8%;收光曲线照明时路面照度总均匀度并不比非收光曲线照明低;对称型收光曲线拱顶单光带布设时,横向偏0.45 m时照明效果最佳。 相似文献
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《现代隧道技术》2017,(1)
驾驶员前方视野直接影响其对危险状况的预判和处理,侧壁属于驾驶员驾车经过公路隧道时前方视野感知域的重要组成部分,因此对行车安全具有一定的影响。文章首先采用分光辐射式亮度计对不同侧壁材料的照明参数进行测定。然后结合自主研发的公路隧道照明环境模拟和效果评价装置开展试验。通过室内模拟具有相同亮度指标的公路隧道照明环境,以反应时间评价视野感知域内三种侧壁涂料对驾驶者视觉功效的影响,从而探索公路隧道照明安全节能的新途径。试验结果表明:使用蓄光反光涂料的公路隧道侧壁可显著提高照明环境亮度;在同种LED灯照明条件下,使用反射率较高且反射光光谱中黄绿光成分较多的侧壁涂料有助于提高驾驶者的视觉功效,从而有利于公路隧道的行车安全和照明节能。 相似文献
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Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD). An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip. It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links. 相似文献
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This paper estimates the efficiencies and productivity changes of 12 international airports in the Asia-Pacific region based on data from 1998 to 2006. We apply stochastic frontier analysis (SFA) to compute efficiency estimates and use the Malmquist productivity index (MPI) to analyze productivity changes. We use the SFA model with a translog-type production function after testing the statistical hypotheses. According to the results of the SFA hypothesis tests, airports have experienced a technological regression; the deviations from the efficiency frontier are caused more by technical inefficiency than random noise. However, the inefficiency was found to decrease. The MPI reveals a declining trend resulting more from technological change than from efficiency change, with a decrease in inefficiency. Taken together, both the hypothesis tests and the MPI not only provide consistent conclusions, but also suggest that airports should concentrate on technological progress. 相似文献
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明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。 相似文献
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In India pedestrians usually cross the road at mid-block crosswalks due to ease of access to their destination or the development of adjacent land use types such as shopping, business areas, school and residential areas. The behaviour of pedestrian will change with respect to different land use type and this change in behaviour of pedestrian further reflects change in perceived level of service (LOS). So, it is important to evaluate the quality of service of such crossing facilities with respect to different land-use type under mixed traffic conditions. In this framework, pedestrian perceived LOS were collected with respect to different land-use type such as shopping, residential and business areas. The ordered probit (OP) model was developed by using NLOGIT software package, with number of vehicles encountered, road crossing difficulty as well as safety considered as primary factors along with pedestrian individual factors (gender and age), land-use type and roadway geometry. From the model results, it has been concluded that perceived safety, crossing difficulty, land-use condition, number of vehicles encountered, median width and number of lanes have significant effect on pedestrian perceived LOS at unprotected (un-signalized) mid-block crosswalks in mixed traffic scenario. The inferences of these results highlights the importance of land use planning in designing a new set of pedestrian access facilities for unprotected mid-block crosswalks under mixed traffic conditions. Also the study results would be useful for evaluating pedestrian accessibility taking into account different land-use type and planning required degree of segregation with vehicular movement at unprotected mid-block crosswalk locations. 相似文献
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管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一(各因素的分值范围都是0~100分),为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。 相似文献