Effect of strata properties and panel widths on chock performance

The selection of optimum chock (support) capacity is very crucial for a successful longwall mining. The selection of chock capacity depends on the site-specific geotechnical parameters, constraints and longwall panel geometry, which are generally not known in detail in priority. Hence, based on the field and laboratory data, various possible combinations should be analyzed to cater for the unforeseeable mining conditions. This paper discusses the use of numerical model for selecting an appropriate chock capacity based on the site-specific geological and geotechnical information and longwall panel geometry. The fracture mechanisms of immediate and main roofs are also discussed for various panel widths and support capacities. For the models considered, the chock convergence is predicted to increase by about 33% due to the increase in face width from 100 to 260 m. Similarly, the massive roof strata are found to yield higher chock convergence compared to bedded strata.     

密斯之范思沃斯住宅阅读体会

经过长达五年的拉锯战，建筑师和业主协议关系终于不那末愉快地画上句号；5年对于一件不足200m^2的单层建筑来说，它所倾注建筑师极端个性的艺术才华和精力，是漫长的；她用无声的建筑语言诉说着他“少即是多”，“上帝存在于细节中”的警世名言和传递着划时代的生活理念。摈弃众多纷纭建筑界评论，现实对建筑师的反馈依然是那末丰厚，成就了建筑师，也成就了建筑界的奇葩一支。     

A coupled photocatalytic-biological process for degradation of 1-amino-8-naphthol-3, 6-disulfonic acid (H-acid)

 There has been growing emphasis on the development of coupled treatment systems (e.g., advanced oxidation–biological) for treating poorly biodegradable wastewater. An attempt has been made in the present study to couple photocatalytic (TiO₂/UV) pretreatment with conventional activated sludge process to achieve improvement in the biodegradation of H-acid. The combination of titanium dioxide and UV light has been known to generate strong oxidants that degrade several organic pollutants into carbon dioxide via the formation of some intermediates. The intermediates formed may undergo biodegradation readily. Accordingly, photodegradation experiments were carried out initially at an optimized TiO₂ dose and the minimum pretreatment time required for transforming H-acid was identified. For this purpose, UV–vis spectrophotometry and high-performance liquid chromatography (HPLC) were extensively used. Subsequently, it was attempted to biodegrade untreated and pretreated H-acid using activated sludge from the textile industry acclimatized to H-acid. It was found that photocatalytic pretreatment of H-acid for 30 min, during which period approximately 8–10% chemical oxygen demand (COD) removal occurred, can be coupled to second-stage biological treatment for achieving enhanced biodegradation of H-acid.     

长江沿岸中小城市的规划对策

近年来,长江沿岸中小城市经济规划发展已经逐渐受到人们关注,这些城市大多拥有景观、文化等方面的特点,同时也面临一些问题。针对长江沿岸中小城市的自身特点和发展机遇,本文将从空间规划、交通组织、景观设计、岸线利用、防洪等几个方面探索长江沿岸中小城市的规划对策。近年来,随着长江三角洲经济圈的飞速发展,人们的注意力开始越来越多地集中到长江流域,而经济较发达的长江三角洲只是很小的一部分,除此之外的广大区域其实是由许多经济实力普遍不强的中小城市组成,因此,沿江中小城市的经济腾飞是促进整个长江流域经济全面发展的基础。在一…     

贵州省100个示范小城镇对外交通联络研究

小城镇作为城乡之间的中转站和联系的纽带,在区域经济发展中发挥着十分重要的作用。为贯彻落实贵州省委、省政府提出的重点扶持100个示范小城镇建设的精神,必须不断提高小城镇的交通可达性,促进小城镇经济社会的跨越发展。     

Monitoring of particulate pollution —an inexpensive technique

Air quality monitoring has become a very important task. Conventional methods for monitoring particulate matter are tedious and require considerable effort and manpower. This paper provides the results of investigations in developing an inexpensive technique to monitor air pollution due to particulate matter. Three plants (i) Pedilanthus tithymaloides, (ii) Pedilanthus varigatum and (iii) Nephrolepis exaltata are selected for the study.

From the investigations, it is found that the inexpensive technique is very useful in developiong and under developed countries. It is also established that certain types of plants are quite effective in arresting particulate matter.     

New correlations for estimation of monthly average daily solar radiation on a horizontal surface using meteorological data

This study deals with the estimation of monthly average daily global solar radiation incident on a horizontal surface at a location using meteorological data for different cities of Andhra Pradesh state. The regression equations of two types of models are developed for various locations of the state having varied climatic regions using measured meteorological parameters obtained from different measuring stations. Parameters such as the latitude and height of the location, maximum and minimum temperature and relative humidity are considered to develop linear and quadratic regression equations to estimate the monthly average daily global radiation. The estimated values are compared with measured data and with other theoretical models in terms of mean percent errors calculated using recognised statistical criteria of MBE, MABE, MPE and RMSE. The proposed quadratic model performs better than the proposed linear models and shows good agreement with the long-term pyranometer data of various locations with a deviation of less than 10%. In comparison with other theoretical models presented so far, the suggested models are expected to perform with a higher degree of accuracy.     

浅谈火力发电厂主厂房钢结构设计研究

根据我国最新的电力发展议案,国内的火力发电站都应该进行全面地改造,特别是一些生产用电和工业用电的大省。因此,整体钢结构的设计是必不可少的要素。本文主要从火电站主厂房钢结构的设计出发,研究了设计的方向和当中会出现的问题。     

铁路沿线住宅小区声环境影响评估及防治对策

该文通过安徽省淮南市铁路沿线两个地块噪声环境的现场实测,分析铁路噪声的特性、空间分布、传播途径及规律及铁路噪声的影响,为保证住宅小区的声环境质量,对拟建住宅小区的声环境进行评估、预测模拟,提出该沿线两个地块住宅小区建设中应采取的防治对策及措施。     

PBBs, PBDEs, and PCBs in foods collected from e-waste disassembly sites and daily intake by local residents

This study was conducted to estimate the total daily dietary intakes (TDIs) of three PHAHs subfamilies for residents living around the large e-waste disassembly sites in the Zhejiang province of China. A total of 191 food samples (including seven food groups and drinking water) were obtained from the disassembly sites and the control site in April, 2007. The levels of three PHAHs were measured by GC-MS. The estimated TDIs of PBBs (385.5 ng day^− 1), PBDEs (195.9 ng day^− 1), and PCBs (12,372.9 ng day^− 1) in the disassembly sites were approximately 2-3 times higher than those in the control site, which suggested that these PHAHs from e-waste might have entered into the food chain. Rice appeared to be the food group showing the highest contribution to the individual dietary intakes of these PHAHs. The estimated TDIs were also compared with those results reported recently in the literature and their respective reference doses by WHO (or Health Canada). By and large, although the estimated TDIs for the PHAHs under study were lower than their respective reference doses, they were obviously higher than those observed in other places listed in the literature, thus suggesting that residents living around the disassembly sites have been exposed to higher levels of PHAHs than those places, and might thus be at greater health risk.