基于声纳渗流技术的地铁联络通道涌水探测应用研究

针对复杂水文地质条件的地铁区间隧道联络通道涌水风险,引入声纳渗流技术探测联络通道区域内地下渗流场特征,采用三维流速矢量声纳测量仪分别进行洞内无损探测和地表井孔测量,综合判断探测区域内的渗流场分布规律。研究结果表明:声纳渗流技术可以在水文地质勘察和涌水渗漏治理中应用,快速准确地测量渗水路径、补给来源以及流速、流向、流量、渗透系数等量化指标,以此建立地下渗流场三维可视化云图,科学指导工程降水设计、涌水渗漏处理,并能验证注浆堵漏处理效果,提前防控暗挖隧道涌水渗漏风险,可为类似工程的安全风险管控提供借鉴和参考。     

环境监测现场工作流程解析

在监测准备过程中,按照明确监测内容,收集现场资料,制定监测方案,监测人员落实及培训,监测仪器材料准备;在现场监测过程中,按照到达监测现场安顿,现场监测前评估,开始监测采样,监测资料数据收集,样品保存与运输;在监测结束过程中,按照监测结束评估,监测现场恢复,样品及资料交接,返回前最后检查,监测设备交接,进行监测总结等现场监测的基本过程,对环境监测中现场工作流程进行了解释和分析.     

浅层小尺度隐伏断层地表勘探的正演模拟及应用

采用二维声波方程有限差分法对浅层小尺度隐伏断层地质模型的地震波场响应进行数值模拟,分别从震源位于断层下降盘顶、断层上升盘顶及断层顶三个不同位置进行正演模拟,对地震波场在断层模型中的传播规律及其地震记录变化特征进行了详细分析。结果表明多个单炮记录的变化对比不仅可以对断层进行快速有效的判断,而且为分析断层几何类型、估计断裂带范围与宽度等方面提供重要的依据。同时将模拟结果应用到实际生产中,取得了较好的应用效果。该方法能有效辅助实际野外工作中对断层的判断,为合理设计观测系统及采集参数设置提供指导,对提高浅层地震勘探现场工作效率和精度具有重要作用。     

Residue levels of fenitrothion and aminocarb in the air samples collected from experimental spray blocks in New Brunswick in 1982

Abstract

Fenitrothion and aminocarb formulations were aerially sprayed over mixed coniferous forests near Fredericton and Bathurst, New Brunswick, Canada. Insecticide concentrations inside the spray blocks were measured at intervals of time by trapping the airborne toxicants in a fritted‐glass bubbler containing dimethylformamide (DMF). The residues in DMF were analysed by gas chromatography. Concentrations of the insecticides in the air sampled decreased rapidly with time from peak levels of 1997 ng/m³ (fenitrothion) and 1201 ng/m³ (aminocarb). Concentrations of the two insecticides in the air samplers were dependent upon the nature of the chemicals, type of formulation used, spray timings and other environmental factors.     

Inherently Safer Design for low-temperature process during depressurization: An industrial case study

The exploitation of a low-quality gas field with high CO₂ concentration is more viable through liquid CO₂ produced from cryogenic distillation technology. Despite the bright potential of the technology, there are deficiencies in handling high concentration of CO₂ at low temperature and high pressure during the blowdown condition. This study focuses on the CO₂ blowdown at a cryogenic pilot plant designed to manage high concentrations of CO₂ in the feed gas, high pressures, and low temperatures. A comprehensive design review and risk assessment using Inherent Safer Design (ISD) indexes were carried out in this study. The ISD was performed to identify the current risk level, and the critical parameters that may cause solid CO₂ formation in the piping or equipment as well as to identify mitigation measures to avoid the temperature to drop below the CO₂ freezing point during blowdown. The present findings confirmed that the initial pressure and temperature, as well as CO₂ concentration are key parameters towards significant impact on blowdown conditions. Therefore, the reduction of the feed gas pressure from 80 bar to 70 bars has minimized the Joule Thomson (JT) effect during blowdown and avoided the CO₂ solid formation in the system. Moreover, the relocation of the blowdown valve at the downstream heater resulted in a higher final temperature above the CO₂ freezing point. The ISD indexes confirmed that the cryogenic facilities are inherently safer during blowdown with the mitigation measures adopted.     

输油管道冻胀安全性温度场有限元分析

冻土区输油管道在投产运行过程中,由于管道沿线受到冻融影响引起的管线变形破坏现象比较普遍。已建的中俄原油管线由漠河进入中国,经过我国北方多年冻土区和季节冻土区直至大庆。输油管道在寒区运行过程中与周围土体发生了热交换,使原自然土层热交换体系改变,进而对运行的管线造成不利的影响如冻胀和融沉。本文对此进行研究为管道安全运行提供参考依据。     

基于无线局域网(WLAN)的油田安全监控系统研究

针对油田监控对象具有点多、面广、跨区域的特点,指出对油田进行无线监控的必要性,并对6种常见的无线通信手段的特点进行比较;根据油田安全监控的业务需求,提出基于WLAN技术的油田安全监控系统硬件结构和软件功能设计方案;并结合工程实施案例介绍系统中无线设备的选型、安装和防雷接地等方面的工程问题。该研究成果实现油田的安全监控预警,减少或避免事故发生的可能性,有利于提高油田安全管理的科学性,具有实用推广价值。     

Six Common Mistakes in Conservation Priority Setting

A vast number of prioritization schemes have been developed to help conservation navigate tough decisions about the allocation of finite resources. However, the application of quantitative approaches to setting priorities in conservation frequently includes mistakes that can undermine their authors’ intention to be more rigorous and scientific in the way priorities are established and resources allocated. Drawing on well‐established principles of decision science, we highlight 6 mistakes commonly associated with setting priorities for conservation: not acknowledging conservation plans are prioritizations; trying to solve an ill‐defined problem; not prioritizing actions; arbitrariness; hidden value judgments; and not acknowledging risk of failure. We explain these mistakes and offer a path to help conservation planners avoid making the same mistakes in future prioritizations. Seis Errores Comunes en la Definición de Prioridades de Conservación     

Carrousel氧化沟的三维流场模拟与分析

利用CFD的Fluent软件，采用标准的三维K—ε紊流模型，对桂林市七里店污水处理厂1#氧化沟的流场进行了数值模拟，对导流墙和推进器附近的流速进行了计算分析。结果表明，氧化沟下层流速较低，局部区域流速低于0．2m／s。为了防止污泥沉降，应进一步降低推进器位置。能量损失分析表明，卡罗塞氧化沟能量损失主要来源于沿程摩擦损失和局部损失。可通过增加墙体光滑度、降低入口高度以及增加导流墙的曲率半径等措施减少能量损失，改善现有氧化沟的水力特征。     

Temperature profile across the combustion zone propagating through an iron particle cloud

Knowledge of the mechanism of combustion zone propagation during dust explosion is of great importance to prevent damage caused by accidental dust explosions. In this study, the temperature profile across the combustion zone propagating through an iron particle cloud is measured experimentally by a thermocouple to elucidate the propagation mechanism. The measured temperature starts to increase slowly at a position about 5 mm ahead of the leading edge of the combustion zone, increases quickly at a position about 3 mm ahead of the leading edge, reaches a maximum value near the end of the combustion zone, and then decreases. As the iron particle concentration increases, the maximum temperature increases at lower concentration, takes a maximum value, and then decreases at higher concentration. The relation between the propagation velocity of the combustion zone and the maximum temperature is also examined. It is found that the propagation velocity has a linear relationship with the maximum temperature. This result suggests that the conductive heat transfer is dominant in the propagation process of the combustion zone through an iron particle cloud.