西成客专房家湾隧道白云岩岩溶治理研究

房家湾隧道砂质白云岩节理裂隙发育,沿节理裂隙岩溶发育且情况复杂、隐蔽,围岩稳定性差,隧道结构安全及运营安全风险较大.针对存在的较大安全风险隐患,为保证隧道施工和运营安全,通过超前地质预报、综合补充勘察技术探查岩溶发育情况.采用综合预加固措施提高围岩自承能力,在地表沟谷铺砌封堵地表水下渗,动态优化隧道衬砌结构、防排水系统...     

振动减速带的速度控制效果研究

车速是影响道路交通安全的一个重要因素,提高速度控制技术的功效,对于改善道路安全性具有重要的意义。文章通过对振动减速带的车辆速度进行观测和分析,评价了速度控制设施的减速效果。     

Dynamic optimization of ship energy efficiency considering time-varying environmental factors

Nowadays, optimization of ship energy efficiency attracts increasing attention in order to meet the requirement for energy conservation and emission reduction. Ship operation energy efficiency is significantly influenced by environmental factors such as wind speed and direction, water speed and depth. Owing to inherent time-variety and uncertainty associated with these various factors, it is very difficult to determine optimal sailing speeds accurately for different legs of the whole route using traditional static optimization methods, especially when the weather conditions change frequently over the length of a ship route. Therefore, in this paper, a novel dynamic optimization method adopting the model predictive control (MPC) strategy is proposed to optimize ship energy efficiency accounting for these time-varying environmental factors. Firstly, the dynamic optimization model of ship energy efficiency considering time-varying environmental factors and the nonlinear system model of ship energy efficiency are established. On this basis, the control algorithm and controller for the dynamic optimization of ship energy efficiency (DOSEE) are designed. Finally, a case study is carried out to demonstrate the validity of this optimization method. The results indicate that the optimal sailing speeds at different time steps could be determined through the dynamic optimization method. This method can improve ship energy efficiency and reduce CO₂ emissions effectively.     

Contrasting the direct use of data from traffic radars and video-cameras with traffic simulation in the estimation of road emissions and PM hotspot analysis

This study investigates the effect of traffic volume and speed data on the simulation of vehicle emissions and hotspot analysis. Data from a microwave radar and video cameras were first used directly for emission modelling. They were then used as input to a traffic simulation model whereby vehicle drive cycles were extracted to estimate emissions. To reach this objective, hourly traffic data were collected from three periods including morning peak (6–9 am), midday (11–2 pm), and afternoon peak (3–6 pm) on a weekday (June 23, 2016) along a high-volume corridor in Toronto, Canada. Traffic volumes were detected by a single radar and two video cameras operated by the Southern Ontario Centre for Atmospheric Aerosol Research. Traffic volume and composition derived from the radar had lower accuracy than the video camera data and the radar performance varied by lane exhibiting poorer performance in the remote lanes. Radar speeds collected at a single point on the corridor had higher variability than simulated traffic speeds, and average speeds were closer after model calibration. Traffic emissions of nitrogen oxides (NOx) and particulate matter (PM₁₀ and PM_2.5) were estimated using radar data as well as using simulated traffic based on various speed aggregation methods. Our results illustrate the range of emission estimates (NO_x: 4.0–27.0 g; PM₁₀: 0.3–4.8 g; PM_2.5: 0.2–1.3 g) for the corridor. The estimates based on radar speeds were at least three times lower than emissions derived from simulated vehicle trajectories. Finally, the PM₁₀ and PM_2.5 near-road concentrations derived from emissions based on simulated speeds were two or three times higher than concentrations based on emissions derived using radar data. Our findings are relevant for project-level emission inventories and PM hot-spot analysis; caution must be exercised when using raw radar data for emission modeling purposes.     

Explaining shipping company participation in voluntary vessel emission reduction programs

Ports are under increasing pressures to increase sustainability and reduce the local and global emissions impacts associated with their operations. Due to limits on their jurisdictional authority, ports may design effective voluntary programs and appropriately motivate participation from global shipping companies that visit their ports. This paper investigates the success of the Vessel Speed Reduction Program at the Ports of Los Angeles and Long Beach and uses qualitative methods to analyze the factors that contributed to the success of the program at reducing local air quality pollutants. In particular, why did individual private firms participate in a non-required, voluntary effort? This research found that external pressures such as community concerns about emissions and regulatory threats are important to motivating voluntary behavior and may even be more important than financial incentives. Furthermore, simplicity of program design, clear goals and presence of a monitoring mechanism are important in influencing participation. These findings broaden our understanding of the business strategy behind slow steaming and its applicability as an operational practice as much work to date is focused on how fuel prices and financial incentives influence the choice for shipping companies to slow their speeds. While the VSR program led to significant emission reductions, an additional lesson for voluntary programs is the need for them to evolve and strive for continuous improvement.     

大型油船航速估算方法

对现有的船舶航速估算方法分析比较，提出了大型油船的航速估算方法。其中有效功率估算是根据上海船研所肥大船系试验图谱和实船试验资料经分析、修正得出，与荷兰Ｈｏｌｔｒｏｐ法、大连造船厂法比较，本文方法均方差最小，估算值与试验值最接近；自航因子估算以ＳＳＰＡ大油轮系列自航试验资料为基础，用上海船研所大量肥大船模型自航试验数据修正得出。     

磁悬浮列车定位测速及数据传输方法研究

分析了磁悬浮列车信号通信系统的特点，由于磁悬浮列车无法使用轨道电路，着重分析了微波和轨间电缆在定位测速及数据传输中的各种应用方法，给出了估算公式，比较了各种方法的优缺点。在以上分析的基础上，结合我国磁悬浮列车的发展情况，提出了适合我国现阶段的定位测速及数据传输的方案，并介绍了相关试验结果。     

Reducing speed and fuel transfer of the Green Flag Incentive Program in Kaohsiung Port Taiwan

This research applied the Green Flag Program to assess the benefits of reducing speed and fuel transfer for large merchant vessels (bulk and container) entering Kaohsiung Port. This study adopts an activity-based model to calculate fuel consumption and emissions, as well as setting up two scenarios, (1) decrease vessel speed to 12 knots 20 nm away from port; and (2) decrease vessel speed to 12 knots and transfer fuel 20 nm away from port, which based on the Green Flag Program in Long Beach, in the U.S. The findings are (1) In scenario one, the container and bulk vessels saw reductions in CO₂ emissions of about 41% and 14%, respectively. In scenario two, container and bulk vessels had reductions of about 48% and 43% in SO₂ emissions, respectively. (2) Large vessels are more environmentally friendly than small vessels. (3) Using the CATCH model to assess the effectiveness of the two scenarios, it was found that container vessels benefited from both reducing speed and fuel transfer, while bulk carriers only did so from the former.     

沪宁城际铁路下蜀黏土路堑边坡设计研究

在系统总结宁镇丘陵地区长江高阶地下蜀黏土的野外分布特征、物理力学性质的基础上,分析评价下蜀黏土具有弱膨胀性、水理性差等不良工程特性。以沪宁城际铁路路基工点设计为例,详细介绍下蜀黏土路堑边坡需根据工点工程地质和水文地质条件、边坡高度,结合当地气候特点,采用绿色植物防护和工程防护相结合的原则进行处理,以及重点地段采取特殊支挡防护的设计方案,提出下蜀黏土路堑边坡勘察设计需重点关注的问题。     

Reducing emissions through speed optimization in supply vessel operations

This paper examines how optimizing sailing speeds can reduce supply vessels emissions in the upstream supply chain to offshore installations. We introduce several speed optimization strategies to be used in construction of periodic vessel schedules. The strategies consider vessel waiting times before the start of service at installations and at supply base. Tests carried out on real instances from Statoil’s activities on the Norwegian continental shelf indicate that a 25% emissions and fuel cost reductions can be achieved without fleet size increase.