漓江游船变更为柳江游船的可行性分析

漓江旅游客船变更为柳江旅游客船存在的技术问题是适用规范的不同,文章从船体结构、船舶稳性、船舶干舷、船舶设备等方面,分析了漓江旅游客船变更为柳江旅游客船的可行性。     

漓江旅游客船回转性研究

文章借助船舶回航试验报告的有关数据和试验评价,分析了舵要素对漓江游船操纵性的影响,并提出了增强漓江旅游客船回转性的设想,为类似水域条件的船舶操纵性设计提供依据。     

广西旅游客船乘客安全疏散研究

为了解决目前广西旅游客船的大规模人群疏散问题,文章基于人类行为心理学特点建立了危急情况下人群的运动模型,分析了广西旅游客船大规模人群疏散方案的可行性,并采用智能算法进行乘客逃生的模拟仿真实验,验证了智能算法能够很好地解决广西旅游客船大规模人群疏散问题。     

桂林港漓江旅游客船船舶污染物防治措施研究

文章以桂林港旅游客船船舶污染物为研究对象,通过对船舶污染物接收转运及处置现状分析,指出其中存在的问题,并提出加强防治船舶污染物的措施。     

漓江航标的变迁——从三角浮标到PE浮鼓

漓江的桂林至阳朔段航道长89．2km,是桂林市旅游的黄金水道,沿河两岸“山清、水秀、洞奇、石美”,还有“深潭、险滩、流泉、飞瀑”佳景,河道蜿蜒曲折,流经喀斯特蜂林谷地之间,山光水色交相辉映,素有“桂林山水甲天下”之美誉,是酋批国家4A级旅游景区和举世闻名的旅游胜地。     

我国水上高速客运发展特点的分析与展望

<正> 水上高速客运,以其特有的快速、方便和独到的适应能力,于80年代率先在珠江三角洲地区迅速发展,随即扩展至长江流域及长江三角洲地区,并在一些经济较发达地区开始取代传统的常规客船而成为水上客运的主力,发展势头强劲。当前水上高速客运使用的高速客船,汇集了当今科技发展的最新成果,在材料、工艺、设备、动力及自动化操控等方面均达到较高水准。因而在实际营     

双肢薄壁墩连续刚构桥抗撞性能研究

连续刚构桥常位于航道之上,其双肢薄壁墩截面尺寸较小,抗船撞能力可能会有不足。文章以实际工程为背景,研究了双肢薄壁墩连续刚构桥抗撞性能。在计算分析通航船舶、撞击参数、结构撞后响应及抗撞性能后发现,连续刚构桥具有较好的抗撞效果,只需设置简单的防撞击设施,就能对船舶和桥墩起到良好的保护作用,同时从桥型、结构和配筋上深层次地分析了抗撞性能好的成因。研究成果可为同类桥梁抗撞方面提供借鉴。     

一种骨架密实型沥青混合料AC-25组成设计研究

为提高广西湿热地区沥青混合料的抗车辙性能,文章根据矿质混合料的级配理论,针对粗集料颗粒的体积特征,提出一种均匀骨架密实抗车辙型沥青混合料组成设计,并采用粗集料间隙率VCA法评价该沥青混合料的骨架特征,同时对沥青混合料的体积参数等进行了研究.结果表明:(13.2～26.5)mm的粗集料用量相对较多,有利于粗集料之间形成防离析、均匀的骨架嵌挤密实结构.     

隧道反粘式防水板性能试验研究

针对隧道复合式衬砌中光面防水板易出现局部破损窜水、不利于后期渗漏整治等问题,文章通过进行反粘式防水板性能试验,研究了其抗剥离、反复剥离-粘接、防窜水等性能,并对其铺挂和焊接方式进行了探讨。结果表明,反粘式防水板的自粘胶具有自愈性,其抗污能力强,能与后浇混凝土多次剥离和粘接,抗剥离强度随混凝土强度增长而提高;采用钉子或热熔垫片固定反粘式防水板,其承载力均远大于单位面积防水板的自重,能有效固定而不受后续施工影响,爬焊机焊接或直接粘接工艺均可用于防水板的搭接;足尺模拟和实际工程加压注水试验中,水压最高可达1.3 MPa,检测钉子固定部位芯样无窜水痕迹,说明反粘式防水板与二次衬砌混凝土粘结良好,防窜水性能优异,便于开展后期隧道病害整治工作。     

宜万线岩溶隧道的设计

宜万铁路大部分隧道穿越灰岩地带,岩溶极为发育.文章着重介绍宜万线岩溶隧道的设计,包括超前地质预测预报,岩溶突水、突泥的预注浆设计,抗高水压的加强复合式衬砌结构设计,防排水设计以及跨越岩溶洞穴的预设计等.     

Experimental study of the impact of structural geometry and wind direction on vehicle emissions in urban environment

Vehicle emissions inside an urban environment are investigated using a wind-tunnel under neutral atmospheric conditions. The urban environment was formed as street canyon model. The diffusion flow field in the boundary layer inside the street canyon was examined at different locations of varying geometry of the street and wind directions in the downwind distance of the leeward side of the street canyon model. The results show that the vertical velocity increases as the aspect ratio increases and with wind direction increases from θ = 90°. The pollutant concentration increases as the aspect ratio decreases. The pollutant concentration decreases as the wind direction increases from θ = 90°. The pollutant concentration distributions indicate that the variability of the structure, geometry and wind direction inside the street canyon are important parameters for estimating air quality in the urban street canyon.     

Simulations of pollutant dispersion at toll plazas using three-dimensional CFD models

Toll plazas are particularly susceptible to build-ups of vehicle-emitted pollutants because vehicles pass through in low gear. To look at this, three-dimensional computational fluid dynamics simulations of pollutant dispersion are used on the standard k − ε turbulence model. The effects of wind speed, wind direction and topography on pollutant dispersion were discussed. The Wuzhuang toll plaza on the Hefei-Nanjing expressway is considered, and the effects of the retaining walls along both sides of the plaza on pollutant dispersion is analysed. There are greater pollutant concentrations near the tollbooths as the angle between the direction of the wind and traffic increases implying that retaining walls impede dispersion. The slope of the walls has little influence on the variations in pollutant concentration.     

Estimating the environmental costs of port related emissions: The case of Kaohsiung

This study estimates the emission costs of ships and trucks in the Port of Kaohsiung, Taiwan, focusing mainly on particular matter and volatile organic compounds. By calculating annual ship and truck emissions we find that the major contributors are tankers, container ships and bulk ships and trucks. Using a bottom-up methodology, the combined environmental costs of ships and trucks are estimated to be over $123 million per year.     

Spatial variation of roadside C2–C6 hydrocarbon concentrations during low wind speeds: A note

This Note describes an investigation of spatial variations in the ambient concentrations of hydrocarbons in the vicinity of a suburban motorway during five consecutive weekday morning peak periods of unusually warm and calm conditions. Background-corrected downwind concentrations representing the influence of the motorway source were found to be strongly dependant on wind speed and direction. The ambient ethene-to-acetylene concentration ratio was greatest close to the roadside and the effect of wind speed on the ratio had different average profiles for main wind directions due to different rates of dispersal. Higher values were obtained using background-corrected concentrations.     

高墩大跨连续刚构桥非线性稳定计算分析

文章以赫章特大桥为工程背景,以压溃准则为失稳判定准则,利用有限元ANSYS结构分析软件,对采用均布力和集中力两种不同加载方式时的高墩大跨连续刚构桥进行非线性稳定计算。计算结果表明：（1）采用集中力加载方式的计算结果更符合实际情况;（2）失稳模态与风荷载的作用方向有关;（3）结构塑性区域与施加的荷载方式和所施加的风荷载有关。     

东山湾水域夜间通航风险控制与环境改善研究

本文通过对古雷港区东山湾水域夜间航行各项致险因素的研究,提出了规范船舶交通流方面、完善助航标志配布方面、夜间灯光环境方面、港池通航条件方面等各项通航条件的优化措施,并以此为依据提出有序开展夜航和全面开通船舶夜航的建议:对夜间船舶通航风险采取分级分类管控,对夜间重载进出港船舶应采取比空载船舶更加严格的管理和要求,同时,建议东山湾水域夜间污染防治能力和人员救助能力应能够适应全面放开夜航后的需要。     

The impact of weather conditions on bikeshare trips in Washington,DC

Bicycle usage can be affected by colder weather, precipitation, and excessive heat. The research presented here analyzes the effect of weather on the use of the Washington, DC, bikeshare system, exploiting a dataset of all trips made on the system. Hourly weather data, including temperature, rainfall, snow, wind, fog, and humidity levels are linked to hourly usage data. Statistical models linking both number of users and duration of use are estimated. Further, we evaluate trips from bikeshare stations within one quarter mile of Metro (subway) stations at times when Metro is operating. This allows us to determine whether Metro serves as a back-up option when weather conditions are unfavorable for bicycling. Results show that cold temperatures, rain, and high humidity levels reduce both the likelihood of using bikeshare and the duration of trips. Trips taken from bikeshare stations proximate to Metro stations are affected more by rain than trips not proximate to Metro stations and less likely when it is dark. This information is useful for understanding bicycling behavior and also for those planning bikeshare systems in other cities.     

Atmospheric dispersion modeling near a roadway under calm meteorological conditions

Atmospheric pollutant dispersion near sources is typically simulated by Gaussian models because of their efficient compromise between reasonable accuracy and manageable computational time. However, the standard Gaussian dispersion formula applies downwind of a source under advective conditions with a well-defined wind direction and cannot calculate air pollutant concentrations under calm conditions with fluctuating wind direction and/or upwind of the emission source. Attempts have been made to address atmospheric dispersion under such conditions. This work evaluates the performance of standard and modified Gaussian plume models using measurements of NO₂, PM₁₀, PM_2.5, five inorganic ions and seven metals conducted near a freeway in Grenoble, France, during 11–27 September 2011. The formulation for calm conditions significantly improves model performance. However, it appears that atmospheric dispersion due to vehicle-induced turbulence is still underestimated. Furthermore, model performance is poor for particulate species unless road dust resuspension by traffic is explicitly taken into account.     

Economic benefits of introducing LNG-fuelled ships for imported flour in South Korea

As the concerns about air pollution have steadily increased, the perception that ships are the source of pollutants and toxic emissions is also expanding. Thus, the International Maritime Organization (IMO) is tightening maritime regulations to reduce air pollution from ships. Currently, the government and related industries are trying to replace heavy fuel oil with liquefied natural gas (LNG) to counter future IMO regulations. Since the use of LNG is expected to increase costs, it is necessary to estimate the social benefits to determine the legitimacy of the replacement. The purpose of this study is to analyse the public’s willingness to pay (WTP) for products imported in LNG-fuelled ships using the contingent valuation method. Flour, the most of which is currently imported in South Korea, is chosen as the subject of empirical analysis. As a result, the mean additional WTP was KRW 571 (USD 0.51) per kg. This value corresponds to about 36% of the existing flour price. Therefore, South Korean households are willing to pay a considerable premium on the flour imported via LNG-fuelled ships. These results can serve as useful bases for future LNG bunkering-related policies.     

Analysis of the operational energy efficiency for inland river ships

This paper looks at the energy consumption and green house gas emissions of inland river shipping, and compares them with the performance of seagoing ships. The analysis is based on a case study of container shipping on the Yangtze River, China. Data were collected under both calm water and real navigation conditions, and energy efficiency operation indices under these conditions are calculated and analyzed. We find that the navigation environment can influence significantly the operational energy efficiency of inland river ships.