Unsaturated creep tests and empirical models for sliding zone soils of Qianjiangping landslide in the Three Gorges

Creep of sliding zone soils may cause significant displacement in large-scale landslides in the Three Gorges reservoir area.To investigate the effects of water on the soil creep behavior of the Qianjiangping landslide,a series of unsaturated triaxial creep tests on the sliding zone soils were performed.Based on the analyses of testing results,a new stress intensity incorporating matric suction was defined and an unsaturated Singh-Mitchell creep model was developed.Predicted results are in good agreement with the experimental results,which indicates that the established unsaturated model can reasonably simulate the effects of water on the soil creep behavior of the landslide.Finally,relationships between matric suction and the parameters of the model were analyzed.This study provides a calculation model and parameters for the evaluation of long-term stability of landslides under the influence of water.     

高原隧道工程机械尾气排放现场测试研究

高原隧道工程机械尾气排放CO和烟雾的现场测试对隧道通风系统设计及隧道施工所需的挖掘机、装载机和自卸汽车数量的匹配有重要的工程价值。以西格线中国铁路第一长隧——关角隧道为依托,进行了多种挖掘机、装载机和自卸汽车CO与烟雾尾气排放的现场测试,测试结果为铁路、公路隧道施工规范中海拔高度修正系数在3600～3800m的范围内取值提供依据和参考,对我国在高原地区修建隧道有一定的参考作用。     

Experimental Investigation of an Office Fire with a Partially Impaired Sprinkler System

In this work, an actual office fire with a partially impaired automatic sprinkler system was investigated. As per regulations, there were four sprinklers in this model office. In the research conducted here, the first three sprinklers were actuated without water supply, while the last sprinkler was supplied with water at the required operating pressure for a period of 30 min. The fire source, a burning plastic trash can filled with 0.5 kg of paper, burned the adjacent chair, desk, desktop computer, and then reached the interior wooden furniture. The results show that the single remaining sprinkler effectively controlled the fire spread for 30 min. The partially impaired sprinkler system does not completely extinguish the fire, but extends the available time for evacuation. Continuing the discharge from sprinklers is preferable since the heat release from the fire increased after water flow was terminated.     

大城市中心区步行街区交通组织研究

本文针对我国大城市中心区步行街区建设情况及其引发的交通矛盾,在分析步行街区交通特征的基础上,提出解决步行街区交通组织基本策略,从内部交通网络、内部与周围道路交通衔接、静态交通等方面提出了步行街区的交通组织对策,并从步行街区的布局、道路规划、出入口规划设计等方面探讨了步行街区的交通规划与设计,最后结合福州市三坊七巷步行街区交通组织进行实例分析。     

Influence of fire ignition locations on the actuation of smoke detectors and wet-type sprinklers in a furnished office

Experiments were conducted in a full-scale model office equipped with movable and fixed fire loads to explore the influence of ignition source (movable fire load(s)) conditions on smoke detector and sprinkler actuation. The interior plan dimension is 5.7 m × 4.7 m and the net ceiling height is 3.3 m. Both northeast and southeast wings have a 2.1 m × 0.9 m single door to be opened. Seven fire scenarios (seven different ignited fire load configurations) under natural ventilation were investigated experimentally. The results show that the amount of fire load at the initial stage in a room fire does not markedly affect smoke generation and does not significantly impact the actuation time of the smoke detectors. When the fire source is located near a corner, the plume corner effect greatly increases; smoke detectors and sprinklers can activate quickly and effectively actuate the fire suppression. When the fire source is located in the room's center, given the uncertainty regarding smoke detector and sprinkler actuation, it may not be possible to control the fire spread.     

A simple method for differentiating direct and indirect exposure to exhaled contaminants in mechanically ventilated rooms

Many airborne infectious diseases can be transmitted via exhaled contaminants transported in the air. Direct exposure occurs when the exhaled jet from the infected person directly enters the breathing zone of the target person. Indirect exposure occurs when the contaminants disperse in the room and are inhaled by the target person. This paper presents a simple method for differentiating the direct and indirect exposure to exhaled contaminants in mechanically ventilated rooms. Experimental data for 191 cases were collected from the literature. After analyzing the data, a simple method was developed to differentiate direct and indirect exposure in mixing and displacement ventilated rooms. The proposed method correctly differentiated direct and indirect exposure for 120 out of the 133 mixing ventilation cases and 47 out of the 58 displacement ventilation cases. Therefore, the proposed method is suitable for use at the early design stage to quickly assess whether there will be direct exposure to exhaled contaminants in a mechanically ventilated room.     

基于无人机的倾斜摄影平台开发

利用无人机采集倾斜摄影数据,改变了传统的测绘作业方式,大幅度提升了作业效率。基于开发出适合小型无人机专用的倾斜摄影平台的目的,利用多台小型相机,通过对摄影平台结构、相机拍照控制、相机数据传输等多个关键技术的研究,开发出了一种轻量级的五拼相机,极大地拓展了倾斜摄影数据采集的手段,提高了数据采集的效率。     

Relative survival of Bacillus subtilis spores loaded on filtering facepiece respirators after five decontamination methods

This study determines the relative survival (RS) of Bacillus subtilis spores loaded on an N95 filtering facepiece respirator (FFR) after decontamination by five methods under worst‐case conditions. Relative survival was obtained by testing after decontamination and after storing the FFRs at 37°C and 95% relative humidity for 24 hours. The decontamination methods involved ethanol, bleach, ultraviolet irradiation (UVA 365 nm, UVC 254 nm), an autoclave, and a traditional electric rice cooker (TERC) that was made in Taiwan. Without decontamination, 59 ± 8% of the loaded spores survived for 24 hours. When 70% ethanol was added to the N95 FFR at a packing density of 0.23, the RS was 73 ± 5% initially and decayed to 22 ± 8% in 24 hours. Relative survival remained above 20% after 20 minutes of UVA irradiation. The other four decontamination measures achieved 99%‐100% biocidal efficacy, as measured immediately after the methods were applied to the test FFRs. Relative survival is a useful parameter for measuring sterilization or degree of disinfection. Bleach, UVC, an autoclave, and a TERC provide better biocidal efficacy than ethanol and UVA. Not only a higher filter quality but also a lower value of RS produced the most decontaminated FFR.     

对一种电梯门安全回路短接装置的分析

1 电梯检验中发现一种门安全回路短接装置 2012年11月13日,江门市特检院按照企业报检要求对某单位新装的8台电梯进行验收检验。在检验过程中发现,现场的某型号小机房电梯的机房控制柜中设置有对门安全回路进行短接的电气装置（如图1所示）。