GEDO IMS系统在有砟铁路精测中的应用

由于有砟铁路的精测工作效率与精度要求极高,常规人工测量手段精度低,轨道几何状态测量仪的测量速度慢,无法满足有砟铁路的捣固进度.本文介绍了GEDO IMS系统的工作原理,并重点对其应用于有砟铁路的精测效率和精度,以及联合大机捣固作业作全面测试.     

哈尔滨市地铁1号线某站应急监测及数据分析

地铁在运行过程中,隧道难免出现沉降,为了确保地铁安全运行,本文对哈尔滨市地铁1号线某站进行了应急监测及数据详细分析,监测数据表明,在观测期间,轨道各监测点沉降平均值相对车站结构呈下降趋势,监测的轨道沉降相对稳定。     

福建主要港口外轮压舱水生物的分布及其潜在入侵威胁

根据2006～2007年间采自福建省4个主要港口12艘外轮(包括8条集装箱船和4条散货船)的压舱水样品,研究压舱水生物的分布特点,结果表明进入该水域的外来船舶压舱水生物物种丰富度和个体丰度高,共发现浮游植物7门86属240种(包括60种赤潮生物)和浮游动物5门30属52种;经3种网目(20,77,和160μm)筛网收集的不同粒径生物的平均丰度分别为:动物38858.3 ind./m~3(粒径77～160μm)和782.3 ind./m~3(粒径>160μm);植物3625.0 cells./ dm~3(粒径20～77μm)和134.1 cells./dm~3(粒径77～160μm).压舱水生物的分布及生存状态与水样的盐度及水龄相关.初步评估外来压舱水生物排放对福建沿海的潜在入侵风险.     

Organic biomarkers in the twilight zone—Time series and settling velocity sediment traps during MedFlux

The transfer of material through the twilight zone of the ocean is controlled by sinking particles that contain organic matter (OM) and mineral ballast. During the MedFlux field program in the northwestern Mediterranean Sea in 2003, sinking particulate matter was collected in time series (TS) and settling velocity (SV) traps and analyzed for amino acids, lipids, and pigments (along with ballast minerals) [Lee, C., Armstrong, R.A., Wakeham, S.G., Peterson, M.L., Miquel, J.C., Cochran, J.K., Fowler, S.W., Hirschberg, D., Beck, A. Xue, J., 2009b. Particulate matter fluxes in time series and settling velocity sediment traps in the northwestern Mediterranean Sea. Deep-Sea Research II, this volume [doi:10.1016/j.dsr2.2008.12.003]]. The goal was to identify how organic chemical compositions of sinking particles varied as a function of their in-situ settling velocity. The TS record was used to define the biogeochemical character and temporal pattern in flux during the period of SV trap deployment. Temporal variations in organic and mineral compositions are consistent with particle biogeochemistry being driven by the seasonal succession of phytoplankton. Spring diatom bloom conditions led to a high flux of rapidly sinking aggregates and zooplankton fecal matter; summer oligotrophy followed and was characterized by a higher proportion of slowly sinking phytoplankton cells. Bacterial degradation is particularly important during the low-flux summer period. Settling velocity traps show that a large proportion of particulate organic matter sinks at 200–500 m d⁻¹. Organic compositions of this fast-sinking material mirrors that of fecal pellets and aggregated material that sinks as the spring bloom terminates. More-slowly sinking OM bears a stronger signature of bacterial degradation than do the faster-sinking particles. The observation that compositions of SV-sorted fractions are different implies that the particle field is compositionally heterogeneous over a range of settling velocities. Thus physical and biological exchange between fast-sinking and slow-sinking particles as they pass down the water column must be incomplete.     

Coarse Estuary Mouth Ballast Gravel Deposits: A Sourcing Case History

Pebbles and cobbles along the channel margin of the Tayport-Tentsmuir tidal flats rest on eroded surfaces of layered sands. Their origin and source have been hitherto unexplained, although they are evidently relatively local. The compositional assemblage of the well-rounded clasts is compared with those of pebbles in the tills and fluvio-glacial deposits of Fife and Tayside, in the River Earn and in the River Tay at Perth. The closest similarity is with the latter site. It is suggested that the material was transported to Tayport as ballast for lighters prior to trans-shipping of cargoes for Perth from larger vessels moored off Tayport. A sloop or brig of 100 tons would have carried about 20 tons of ballast. Trading by one vessel per week over a time period of a century could have accounted for the transport of 100000 tons of the material concerned. Removal of the ballast by barge from Tayport enabled the building of Lucky Scalp island. Attempts to improve the underfoot conditions for salmon fishing are believed to have been responsible for the spreading of ballast along the outer margin of the tidal flats.     

四川省的一种潜在优势石材资源--铁路道碴用岩石

全国铁路大提速,现有铁路设施急需改造,新建铁路也将按照新的速度标准进行设计和施工。因此,铁路道碴必须按新的质量标准进行更换。市场需求迫切,容量空间巨大,我省此类石材资源具有量大、质优、区位分布合理等优势,应重视和加强铁路道碴石材资源的勘查评价,为四川铁路的全面提速,提供坚实的物质基础。     

桶形基础平台海上沉放安装

桶形基础平台是世界上一种最新型的海洋平台，可广泛应用于海上油气田开发。为满足我国际油气田开发中卫星平台的结构和功能要求，桶形基础平台采用新的压载沉放方法安装，具有更高的效率和经济性。沉放过程中桶形基础平台受到水流和波浪的作用，结合模型试验对平台运动进行数值模拟分析，以了解在整个沉放过程中相应参数的变化趋势。根据桶形基础平台的特征，制定联台沉放方案，并通过压载实现平台的沉放控制。     

中国东南沿海港口外轮压舱水生物的调查

随机选取东南沿海港口的17艘外来船舶(含8条集装箱船和9条散货船)作为监测对象,进行压舱水浮游植物及动物的物种鉴定和丰度测定,并对监测数据进行统计学分析.检出分属于7个浮游植物门类和5个动物门类的309种外来压舱水生物(包括60种赤潮生物).外轮压舱水生物的分布及生存状态与水样的水龄和盐度相关.船舶压舱水排放是大家熟知...     

Treating ballast water with hydroxyl radical on introduced organisms

1 INTRODUCTION The introduction of invasive marine species into new environments by ship’s ballast water, by attaching to ships’ hulls or via other vectors has been recognized as one of the four major threats to the world’s oceans by Global Environment…     

Discrete element modeling of dynamic behaviors of railway ballast under cyclic loading with dilated polyhedra

The dynamic behaviors of railway ballast under cyclic loading are simulated with discrete element method (DEM). Dilated polyhedra are constructed based on the Minkowski sum operator in order to resemble the irregular shapes of ballast particles. The polyhedral particle generation, contact detection between particles and contact laws are presented. Ballast box tests with periodic lateral boundaries are conducted to simulate the dynamics of the sleeper and ballast particles. The settlement and effective stiffness of ballast bed are investigated under cyclic loadings with five distinct frequencies. The settlement of ballast bed is significant in the first several cycles and increases with the number of cycles gradually. The higher frequency loading generates larger displacement in the same simulation time. The effective stiffness of ballast bed increases gradually. To study the effect of particles' sharpness, dilated polyhedra with different dilating radii and spherical particles are also developed. Simulation results show the sharper the ballast particles are, the smaller the produced settlement. Copyright © 2016 John Wiley & Sons, Ltd.