建筑工程施工质量与安全监督

随着我国国民经济的不断发展,建筑行业也发展的十分迅速,在总体的项目建设中占的比例也是最大的,其迅速的发展也带动了结构和功能的显著提升。如何有效控制施工质量,已成为施工管理中的重中之重,同时也对社会的经济发展有着积极的作用。     

浅谈土建项目中的混凝土施工技术

从土建工程的质量与进度来讲,混凝土施工技术的合理应用对其具有决定性的影响。因此,应对混凝土施工技术的应用予以高度地关注。文章分析了其技术,探讨了其应用及控制措施。     

两种黏性土的基质吸力试验对比分析

利用压力板仪器对高液限红黏土和含砂次生黏土进行基质吸力测定试验,通过对比分析及曲线数值拟合,研究了红黏土基质吸力与含水率之间的关系,得出红黏土的土水特征曲线的一些规律。试验证明高液限红黏土比含砂次生黏土采用压力板仪获取的土水特征曲线拟合度更高,保水性更好,含水率变化范围更大,曲线拟合符合指数分布,通过数值模拟得出红黏土路基的含水率动态变化真实可靠。     

大型张弦门墙钢结构综合施工技术

某大型张弦门墙钢结构,因受其结构特性及现场施工条件的制约,使得单一的施工方案均无法满足其施工需求.通过分析论证,采用地面整体水平拼装、结构胎架滑移运输及大型吊机分块吊装的综合施工方案,结构整体安装完成后实际柱顶最大水平误差3 mm,垂直误差2 mm,柱脚对口最大误差为2.5 mm,两侧套筒最大对口误差为2 mm,门墙钢结构跨中最大挠度为10 mm,结构安装精度达到预期效果.     

Characteristics of an atrazine degrading bacterium and the construction of a microbial agent for effective atrazine degradation

A bacterial strain, YQJ‐6, capable of highly degrading atrazine was isolated from soil. Strain YQJ‐6 was identified as Bacillus atrophaeus based on 16S rRNA and the analysis of morphology as well as physiological and biochemical characteristics. The optimal pH value and temperature for strain YQJ‐6 to grow and degrade atrazine were 7.0–7.5 and 30–40°C, respectively. The degradation rate of atrazine (50 mg/L) by strain YQJ‐6 reached approximately 99.2% in 7 days. Strain YQJ‐6 also had a high tolerance to atrazine and could tolerate at least 1000 mg/L atrazine. In addition, strain YQJ‐6 was successfully made into a microbial agent that is easy to commercialize and can be used to treat atrazine residues in soil. The microbial agent containing the strain YQJ‐6 achieved good experimental results. It is believed that strain YQJ‐6 can be used to control atrazine pollution.     

Environmental and individual exposure to secondhand aerosol of electronic cigarettes in confined spaces: Results from the TackSHS Project†

Secondhand electronic cigarette (e-cigarette) aerosol (SHA) might impair indoor air quality and expose bystanders. This study aims to investigate exposure to SHA in controlled conditions of enclosed settings simulating real-world scenario. An experiment was performed in a car and in a room, in which SHA was generated during a 30-minute ad libitum use of an e-cigarette. The experiment was replicated on five consecutive days in each setting. We measured PM_2.5, airborne nicotine concentrations, and biomarkers of exposure to SHA, such as nicotine metabolites, tobacco-specific nitrosamines, propylene glycol, and glycerol in bystanders’ saliva samples before, during, and after the exposure period. Self-reported health symptoms related to exposure to SHA were also recorded. The results showed that the highest median PM_2.5 concentration was recorded during the exposure period, being 21 µg/m³ in the room setting and 16 µg/m³ in the car setting—about twofold increase compared to the baseline. Most concentrations of the airborne nicotine and all biomarkers were below the limit of quantification in both settings. Bystanders in both settings experienced some short-term irritation symptoms, expressed as dry throat, nose, eyes, and phlegm. In conclusion, short-term use of an e-cigarette in confined spaces increased indoor PM_2.5 level and caused some irritation symptoms in bystanders.     

Respiratory bioaerosol deposition from a cough and recovery of viable viruses on nearby seats in a cabin environment

Respiratory bioaerosol deposition in public transport cabins is critical for risk analysis and control of contact transmission. In this work, we built a two-row four-seat setup and an air duct system to simulate a cabin environment. A thermal manikin on the rear left-hand seat was taken as the infected passenger (IP) and “coughed” three times through a cough generator. The deposited viruses and droplets on nearby seats were measured by a cultivation method and microscope, respectively. The effects of seat backrest and overhead gasper jet were studied. Results showed that the number of deposited virus on the front seat was one order of magnitude higher than that on other seats which only contained droplets smaller than 10 µm in diameter. When the backrest was 15 cm higher than the cough, the deposited number of viruses was reduced to 5% of that with the backrest at the same height with the cough. The gasper jet above the IP with a velocity of 1.5 m/s can reduce the deposited viruses to 4% of that with gasper off. It indicates that both the gasper jet and backrest can work as mitigation measures to block the cough jet and protect the nearby passengers.     

存量发展背景下深圳市国土空间规划的探索和思考

《深圳国土空间规划(2020—2035)》(简称"深圳2035")的编制,是在我国迈向"两个一百年"奋斗目标的新征程和经济特区成立40周年的重要时代背景和关键历史节点上开展的,承担着建设粤港澳大湾区和中国特色社会主义先行示范区的重大历史使命,必须落实生态文明与绿色发展理念,坚持目标导向、问题导向和实施导向相结合的原则,...     

某储煤场51m跨度钢栈桥方案优选

结合51m跨度钢栈桥的结构设计,对其结构形式、杆件截面选择及水平支撑布置等内容进行方案比对,并寻求到最优的结构方案。同时也分析了大跨度栈桥设计中的注意事项,供类似工程借鉴。     

圆塔形锚垫板二级台阶对其承载力影响的试验研究

圆塔形锚垫板采用多级台阶的结构形式进行分散传递锚固力,进而提高锚垫板的承载能力。该文以OVM.M15-9D、OVM.M15-12D锚垫板为例,通过改变其结构形式,即去除末端二级台阶,采用ANSYS有限元分析和荷载传递试验的方法,对比研究了其对锚垫板承载能力的影响,并分析了多级台阶在锚下混凝土中的传力形式。