道路运输行业安全监管现状分析及对策研究

结合道路运输行业安全监管现状,从道路运输行业安全监管职责和内容、监管方式、安全检查方面对道路运输行业安全监管存在的问题进行分析,并有针对性的提出了相应的建议和对策。     

双块式轨枕外形质量快速检测系统研制及应用

SK?2型双块式混凝土轨枕是高速铁路无砟轨道结构中的重要预制件,单一生产厂日均产量达到800~1400根,但目前的人工检测方式无法满足双块式轨枕的出厂检验要求。本文提出的双块式轨枕外形质量快速检测系统可满足TB/T 3397—2015《CRTS双块式无砟轨道混凝土轨枕》的出厂检验要求,与双块式轨枕生产线相匹配,大大提高了检测效率,实现了双块式轨枕全参数、自动化、智能化检测。检测数据自动上传至生产管理平台,可对双块式轨枕生产质量进行跟踪管理。     

The problem of cold starts: A closer look at mobile source emissions levels

While the phenomenon of excess vehicle emissions from cold-start conditions is well known, the magnitude and duration of this phenomenon is often unclear due to the complex chemical processes involved and uncertainty in the literature on this subject. This paper synthesizes key findings regarding the influence of ambient and engine temperatures on light-duty vehicle (LDV) emissions. Existing literature, as well as analytical tools like the U.S. Environmental Protection Agency’s Motor Vehicle Emission Simulator (MOVES), indicate that while total vehicle emissions have dropped significantly in recent years, those associated with cold starts can still constitute up to 80% for some pollutant species. Starting emissions are consistently found to make up a high proportion of total transportation-related methane (CH₄), nitrous oxide (N₂O), and volatile organic compounds (VOCs). After 3–4 min of vehicle operation, both the engine coolant and the catalytic converter have generally warmed, and emissions are significantly lower. This effect lasts roughly 45 min after the engine is shut off, though the cooling rate depends greatly on the emission species and ambient temperature. Electrically (pre-)heated catalysts, using the bigger batteries available on hybrid drivetrains and plug-in vehicles, may be the most cost-effective technology to bring down a sizable share of mobile source emissions. Trip chaining (to keep engines warm) and shifting to non-motorized modes for shorter trips, where the cold start can dominate emissions, are also valuable tactics.     

Including congestion effects in urban road traffic CO2 emissions modelling: Do Local Government Authorities have the right options?

Tailpipe emissions from vehicles on urban road networks have damaging impacts, with the problem exacerbated by the common occurrence of congestion. This article focuses on carbon dioxide because it is the largest constituent of road traffic greenhouse gas emissions. Local Government Authorities (LGAs) are typically responsible for facilitating mitigation of these emissions, and critical to this task is the ability to assess the impact of transport interventions on road traffic emissions for a whole network.This article presents a contemporary review of literature concerning road traffic data and its use by LGAs in emissions models (EMs). Emphasis on the practicalities of using data readily available to LGAs to estimate network level emissions and inform effective policy is a relatively new research area, and this article summarises achievements so far. Results of the literature review indicate that readily available data are aggregated at traffic level rather than disaggregated at individual vehicle level. Hence, a hypothesis is put forward that optimal EM complexity is one using traffic variables as inputs, allowing LGAs to capture the influence of congestion whilst avoiding the complexity of detailed EMs that estimate emissions at vehicle level.Existing methodologies for estimating network emissions based on traffic variables typically have limitations. Conclusions are that LGAs do not necessarily have the right options, and that more research in this domain is required, both to quantify accuracy and to further develop EMs that explicitly include congestion, whilst remaining within LGA resource constraints.     

挤密砂桩施工远程自动监控系统设计

为了提高砂桩成桩质量和施工效率,研制一套砂桩施工自动化监控系统并进行现场应用,包括砂桩沉管行程自动监控系统、桩机电流监控系统以及远程监控系统。实测结果表明:行程监控系统可精确记录沉管下沉、上提和反插距离;电流监控系统可实时反映沉桩电流变化,通过行程和电流监控结果对比,电流监控可反映沉桩地层变化和反插效果;行程和电流数据可通过远程监控实时显示和记录。该套系统的研制可实现砂桩成桩精细化管理、解放现场监管人力,提高施工效率。     

Did Chinese cities that implemented driving restrictions see reductions in PM10?

Imposing driving restrictions is becoming increasingly popular as a policy intended to control urban air pollution. Existing studies on this topic offer highly mixed observations, and each study tends to focus on only one city. In this paper, we used 11 Chinese cities with driving restrictions as the treatment group, and compared them to other cities that did not implement the policy. Based on a propensity score matching and difference-in-difference analysis, we found no evidence of a decrease in PM10 concentrations in cities after they implemented driving restrictions. This finding may be attributed to an increase in the number of cars in these cities after implementing driving restrictions, but we also found no evidence of an improvement in air quality for a given number of cars after implementation of the policies.     

Simulating the air quality impacts of traffic calming schemes in a dense urban neighborhood

In this study, the effects of isolated traffic calming measures and area-wide calming schemes on air quality in a dense neighborhood were estimated using a combination of microscopic traffic simulation, emission, and dispersion modeling. Results indicated that traffic calming measures did not have as large an effect on nitrogen dioxide (NO₂) concentrations as the effect observed on nitrogen oxide (NO_x) emissions. Changes in emissions resulted in highly disproportional changes in pollutant levels due to daily meteorological conditions, road geometry and orientation with respect to the wind. Average NO₂ levels increased between 0.1% and 10% with respect to the base-case while changes in NO_x emissions varied between 5% and 160%. Moreover, higher wind speeds decreased NO₂ concentrations on both sides of the roadway. Among the traffic calming measures, speed bumps produced the highest increases in NO₂ levels.     

高等级公路监理工程项目管理综述

监理是一个项目管理的系统工程,有着严格的制度和程序,有助于有效控制工程的进度、质量和费用,实时监测发现施工过程中的问题,第一时间进行反馈,保证路面施工质量,对后续路面开放运营的质量具有明显作用.     

高速公路沥青路面施工质量控制分析

无接缝、平整、行车舒适、噪音低以及振动小、易于养护等优点,使沥青混凝土路面成为我国国内公路面层普遍采用的一种比较好的结构形式。但是如果施工中不能按照施工工艺严格的进行施工质量控制,则很容易导致路面的一系列质量问题,这不仅影响使用功能,还影响影响其社会效益。     

关于大学生心理健康教育课程的几点思考

大学生心理健康教育课程教学的目的是培养学生健康的心理和良好的心理素质,使其在思想认识、知识和技能三个层面学有所获。课程教学应遵循理论与实践相结合、教师讲授与学生体验相结合,通过课堂讲授、小组讨论与典型案例分析、心理素质训练与拓展等体验式教育方法进行教学;采用理论效果评估与实际操作效果评估相结合的方式对课程效果进行评估。