10000m~3真空球罐安全施工技术应用

要实现10000m3真空球罐安全抽真空到10 Pa的目标,须保证10 000 m3真空球罐对曲率精度和密封性的特别要求。真空球罐安装过程中,通过各项技术措施在施工关键工序上的应用,成功实现了抽真空目标并有效保证了大型真空球罐的安全性。     

新型透明黏土制配及其物理力学特性研究

基于人工合成透明土材料和PIV技术的可视化模型试验方法是重要的岩土工程测试手段之一,然而,目前已有透明土材料中针对模拟天然黏土的材料仍相对较少。提出以Carbopol~ Ultrez10聚合物(简称U10)、NaOH粉末和纯净水为原材料,碳纳米材料掺入作为示踪粒子制成散斑场,制配一种新型透明黏土材料的技术方案与操作方法。基于调制传递函数(MTF)方法,对新型透明黏土材料的光学透明性进行量化分析,并与已有透明土材料的光学透明性进行对比分析,验证其优越性。基于微型十字板剪切试验、压缩固结试验、渗透试验及热传导试验等室内试验方法,对新型透明黏土材料的物理力学特性进行系统研究,探讨其模拟天然黏土的可行性。研究结果表明:新型透明黏土材料的光学透明厚度可达25～40 cm,较目前已有常规透明土材料的光学透明厚度提高约2～3倍;新型材料表现为中低灵敏性黏土、强度随时间明显增加,强度、压缩固结特性与天然淤泥(尤其是海相淤泥)或泥炭土的性质相近,渗透系数为2×10~(-7)～7×10~(-7)cm/s,热传导系数为0.62～0.71 W·M~(-1)·K~(-1)。     

Numerical study on PM10 collection efficiency in a wire-cylinder electrostatic precipitator under multi-field coupling

The PM10 collection efficiency of a wire-cylinder electrostatic precipitator (ESP) was studied by means of a developed mathematical model, including the multi-field coupling between the gas flow field, the particle dynamic field and the electric field, and applying the Deutsch–Anderson Equation. The diffusion charging mechanism was considered due to the diameter range of PM10. The investigated variables were the applied potential, the gas velocity and the particle distribution. Numerical results indicate that the diffusion charging has significant influence on PM10 removal performance and the effect is more obvious with the decreasing diameter, and that the PM10 collection efficiency increases with the increasing applied potential and the increment of collection efficiency is more significant at lower voltage. Moreover, as the gas velocity at inlet decreases, collection efficiency of PM10 will increase. Finally, the overall efficiency increases with increasing the mean diameter of particle distribution. The research results can provide theoretical and technical references for the design of novel ESP aiming at economy and environment protection.     

Urban development and particulate air pollution in Coimbatore city,India

Haphazard urbanization and unprecedented vehicular growth that exacerbate air quality are prevalent features in India. Coimbatore, an important industrial city ranking 15th in terms of principal urban agglomerations of India, was classified as a moderately polluted area in National Ambient Air Quality Monitoring survey in 1997. The current study (March 1999–February 2001) was undertaken to assess suspended particulate matter (SPM) in urban and suburban Coimbatore. It was found that in the Coimbatore atmosphere SPM with a diameter of less than 10 µm (respirable fraction, RSPM or PM₁₀) and those with a diameter above 10 µm, the non‐respirable (NRSPM) fraction, ranged between 30–149 µg/m³ and 24.4–460 µg/m³ respectively. The study infers that urban areas, especially those with frequent vehicular traffic and traffic congestion, had comparatively high RSPM exceeding the Indian prescribed standards (60 µg/m³). Emission inventory estimated for current vehicle strength showed that about 840 000 kg of particulate matter was emitted during 2001. Wind speed negatively correlated with RSPM, while it was positively correlated with NRSPM. Temperature had a negative correlation with RSPM values.     

Predicting chaotic time series of PM10 concentration using artificial neural network

Respirable particulate matter (PM10) concentration at one residential site in Delhi, India was predicted using the neural network approach. The concepts of chaotic systems theory were utilized to build the neural network model. The embedding dimension was estimated to provide the inputs to the neural network. The model evaluation results indicated the importance of noise reduction before selecting the embedding dimension of the time series. The selection of a proper embedding dimension is considered to be essential for obtaining reliable predictions. The model’s performance shows the capability of neural networks in modelling the chaotic time series.     

浅析10 kV配网供电可靠性

本文仅从一般的角度分析了提高10 kV 配网供电可靠性的几项措施。在实践的管理活动中,还需要管理人员结合当地的实际情况,探索出适应具体情况的管理方式,以保障配网的供电质量及可靠性,继而带来良好的经济效益及社会效益。     

西安市某办公建筑室内外颗粒物浓度变化特征分析

本文通过建立质量平衡方程对西安市某办公建筑室内颗粒物浓度进行了理论分析,并对该建筑室内外PM10和PM2.5的质量浓度进行了实时监测。结合线性回归方程、室内外监测浓度线性拟合曲线及室内浓度随时间的指数拟合曲线,对该普通办公房间室内颗粒排放源及室内颗粒浓度变化特征进行了研究。结果表明,该建筑室内PM10的平均发尘为7.93～12.48 mg/h,室内PM2.5的平均发尘为2.89～4.08 mg/h;室内PM10和PM2.5呈现指数变化且随时间呈下降趋势。     

基于PSCAD的10kV配电线路接地装置冲击特性研究

在考虑接地电阻火花效应的基础上,采用逐次渐进的算法,得出了模型元件参数,在PSCAD仿真软件中建立10 kV配电线路常用的接地装置仿真模型,对在不同雷电流幅值、不同接地装置尺寸、不同土壤电阻率以及埋设深度下该装置冲击接地电阻的冲击特性进行了仿真,分析常见10 kV配电线路的接地装置冲击特性,为10 kV配电线路的接地装置设计提供了理论数据依据,具有一定的工程应用价值。     

10 kV 变配电所高压系统设计中 MOA 避雷器的选型

分析民用10 kV 变配电系统中的过电压保护,对无间隙氧化锌避雷器的保护原理、设置原则、参数选择进行阐述。以10 kV 小电阻接地系统与经消弧线圈接地系统的避雷器选择为例,阐述避雷器参数的选型。     

五星级酒店中的供配电及照明系统设计

五星级酒店对于供配电及照明系统的要求相当高,这就需要有稳固的电气系统作为支撑。本文通过实际案例(某市级五星级酒店)介绍10/0.4kV变、配电系统、低压配电系统、电气照明系统和应急电源(柴油发电机、EPS、UPS)的设计要点及各系统的构成特点。