散装煤炭船舶火灾的发生与预防

煤炭在船舶运输中的自燃过程是一个复杂的物理、化学反应过程。在这个过程中,煤炭的品级、水分、内表面积和缝隙、通风方式、杂质等因素起着重要作用。论文通过讨论以上过程,总结出在船舶生产运输实践中,控制煤炭自燃的方法,希望能对运输企业有所帮助。     

强割裂海底区有效反射系数的频率特性研究

海底是海洋的反射边界,它有若干与海面相似的特性。但是,由于海底的不同成分和多层的结构,其作用更加复杂,显著地影响声波的传播。声波在海底反射时造成能量损失,同时也造成影区的声场,能量损失会限制其传播距离。研究了强割裂海底区有效反射系数的频率特性,并运用Matlab软件进行了实验仿真。     

有限深度均匀水流中圆柱横向阻力影响特性

为解决规则圆柱桩群阻力计算问题,以指导涉及规则圆柱桩群的物理模型试验和数值模拟计算等工作,在归纳总结已有研究成果的基础上,通过先进的数显式测力设备和较为准确的悬浮测力法,对有限深度均匀水流中多圆柱横向等间距不同方式的排列桩群进行了阻力测试研究,得出了有限深度均匀水流中圆柱横向阻力影响特性规律,并归纳总结出了圆柱横向阻力影响系数的经验公式。通过大量的测试试验数据证实了这些研究规律的准确性、有效性及实用性,对工程实践具有参考价值。     

粤东海域的波浪特性分析

根据粤东海域的波浪观测资料,分析该海域的波浪特性.     

斜交预应力箱梁钢绞线形状特性及其影响

斜交预应力箱梁位于腹板的钢绞线是三维曲线,若简化为平面曲线进行计算,将使下料长度和竖向弯起角与实际有不可忽略的误差,并影响张拉伸长量的计算结果,故有必要结合工程实例对其进行详细介绍。     

沙漠公路交通安全特性

为了对沙漠公路交通安全现状、事故特征和成因进行分析,广泛收集了塔克拉玛干沙漠公路通车以来的交通事故统计数据,并深入实地进行了调研。研究表明沙漠公路交通事故次数春秋高于冬季,午间、傍晚和夜间相对较高;交通事故自北向南逐渐减少,然而事故的严重程度却是由北向南逐渐增加;影响道路交通安全的天气现象主要有沙漠高温和风沙天气,人是导致交通事故的主要因素,主体是汽车驾驶员;道路交通环境极易导致超速和违规;公路沿线绿化工程在一定程度上影响行车安全;沙漠公路上仍然缺乏必要的安全保障设施和应急反应机制。     

The overall effects of road works on global warming gas emissions

Road characteristics influence the amount of pollution generated by traffic. They govern the rolling resistance, which includes: the viscoelastic behaviour of the pavement structure, surface texture, and profile unevenness. Road works are performed on a periodic basis to maintain these characteristics at proper levels of service (e.g. safety, comfort, and noise). While such works produce additional pollution (due to congestion around worksites or extra fuel consumption along the detour route), they still result in less pollution over the long term. This article assesses the balance between an increase in gas emissions during road works and the reduction in emissions from traffic once the works are completed. It is demonstrated that when road works are introduced to correct longitudinal profiles, rather than texture, the emissions benefit is substantial.     

纯粉煤灰路堤土工离心模型试验研究

文章通过土工离心模型试验,研究了不同干密度和含水量对纯粉煤灰路堤变形特征的影响规律;同时也研究了不同边坡坡度对路堤变形的影响。试验结果表明,纯粉煤灰路堤具有自重轻、沉降小和稳定性能高的特点。     

Passenger travel characteristics and bus operational states: a study based on IC card and GPS data in Yinchuan,China

ABSTRACT

In recent years, public transport has been developing rapidly and producing large amounts of traffic data. Emerging big data-mining techniques enable the application of these data in a variety of ways. This study uses bus intelligent card (IC card) data and global positioning system (GPS) data to estimate passenger boarding and alighting stations. First, an estimation model for boarding stations is introduced to determine passenger boarding stations. Then, the authors propose an innovative uplink and downlink information identification model (UDI) to generate information for estimating alighting stations. Subsequently, the estimation model for the alighting stations is introduced. In addition, a transfer station identification model is also developed to determine transfer stations. These models are applied to Yinchuan, China to analyze passenger flow characteristics and bus operations. The authors obtain passenger flows based on stations (stops), bus lines, and traffic analysis zones (TAZ) during weekdays and weekends. Moreover, average bus operational speeds are obtained. These findings can be used in bus network planning and optimization as well as bus operation scheduling.     

乙醇HCCI燃烧特性试验研究

文中对一台双缸四冲程自然吸气直喷柴油机上进行了乙醇的HCCI的试验,试验分析了过量空气系数和进气温度对乙醇均质压燃燃烧特性的影响。研究结果表明:发动机缸压和压力升高率峰值随着进气温度的上升而增加,并且峰值压力也会提前;过量空气系数的增大,缸压和压力升高率减小。与较小的过量空气系数相比,峰值压力的出现明显推迟。过量空气系数对压力升高率的影响较小,但对放热率的影响相当大。