CO2 ocean sequestration by moving ships

Ocean sequestration of the CO₂ captured from fossil-fuel burning is a possible option to mitigate the increase in CO₂ concentration in the atmosphere. It can isolate huge amounts of CO₂ from the atmosphere for a long time at relatively low cost, if it is acceptable from the viewpoint of the environmental impact on the ocean. The concept of CO₂ dispersion in the ocean depths by ships is a promising method for efficient dilution. That is, liquefied CO₂ is delivered to the site and injected into the ocean at depths of 1000–2500 m with a suspended pipe towed by a slowly moving ship. In addition to the horizontal movement of the release point, the vertical journey of CO₂ droplets until they disappear by dissolution is effective for the dilution of CO₂ in seawater. In this paper, the possibility of the generation of relatively large-sized droplets from a moving nozzle is investigated experimentally. In addition, the terminal velocity of CO₂ droplets in deep-sea circumstances is measured in a large high-pressure tank to investigate the influence of the hydrate film formed on the surface of the droplet. Finally, it is shown by simulation that an initial dilution ratio of one to some ten thousandths is possible on a realistic engineering scale in the moving ship type of CO₂ ocean sequestration. Received: August 7, 2001 / Accepted: September 13, 2001     

广州地铁3号线VCC故障情况下的行车组织方案

介绍了基于环线通信,由VCC（车辆控制中心）系统控制的移动闭塞信号设计思想,分析该思想下的追踪原理,并着重以广州地铁3号线为现有条件,重点阐述了VCC故障情况下的行车组织方案,并分析了此种情况下的线路通过能力。     

CBTC系统混跑模式中的移动授权计算

对CBTC系统混跑模式中CBTC列车移动授权的计算原则和计算方式进行了深入研究,并以4种典型的混跑场景为例,阐述了每种场景中的移动授权延伸过程及相应的安全操作规则。     

地铁正线信号机的显示方案分析

对国内地铁正线轨旁信号机的显示方案进行了总结和分析,探讨了信号机的机构设置及显示原则,并提出了统一信号机机构设置原则及显示含义的建议。     

津滨轻轨东海路站折返间隔优化分析

描述了天津津滨轻轨东海路站站后折返问题,分析了折返间隔较大产生的原因,提出了缩短折返间隔的方法及解决办法,并对优化后的折返间隔进行了进一步分析,估算了优化后的折返间隔。     

SelTrac移动闭塞系统VCC I/O输出错误故障原因浅析

以广州市轨道交通3号线及机场线为现有条件,详细介绍了SelTrac系统中的VCC输入输出的数据信息流程,并对VCC I/O输出错误的故障原因进行了具体分析。     

北京局新建调度指挥中心搬迁方案的研究

北京铁路局新建调度指挥中心,既有TDCS/CTC系统将全部搬迁到新调度指挥中心。从运输生产角度出发,根据既有TDCS/CTC系统设备情况,对搬迁方案的原则、方案和实施步骤进行研究,以降低搬迁实施对铁路运输生产影响的风险。     

移动平均法在公交运行时间预测中的应用

运用概率论与数理统计中的移动平均法,本文对公交车运行时间问题进行了研究。利用移动平均法的基本原理和检验方法,结合采集到的长春市公交306路的运行时间数据进行了实证研究,结果表明该方法可以用于公交车运行时间的预测。     

基于移动网格技术的微型客车会车外流场仿真研究

本文采用计算流体力学CFD软件,对微型面包车与大型客车相会进行了会车多工况仿真计算,给出了处于会车特征位置的小车侧面压力值及压力场分布图,为我国实现汽车外形自主研发提供方法借鉴。     

H-adaptive Navier–Stokes simulations of free-surface flows around moving bodies

This article deals with Navier–Stokes simulations of multiphase flows around moving bodies coupled with an adaptive mesh refinement strategy. The numerical framework is considered first: the Navier–Stokes solver, the methodologies for handling multiphase flows and moving bodies, the remeshing techniques, and the adaptive procedure are explained and detailed. Then an application involving hydrodynamic impacts is presented in detail and studied to highlight the relevance of the whole global approach. Of particular interest is the accurate computation of pressure peaks arising during impacts.