Use of waste ash from palm oil industry in concrete

Palm oil fuel ash (POFA), a by-product from the palm oil industry, is disposed of as waste in landfills. In this study, POFA was utilized as a pozzolan in concrete. The original size POFA (termed OP) was ground until the median particle sizes were 15.9 microm (termed MP) and 7.4 microm (termed SP). Portland cement Type I was replaced by OP, MP, and SP of 10%, 20%, 30%, and 40% by weight of binder. The properties of concrete, such as setting time, compressive strength, and expansion due to magnesium sulfate attack were investigated. The results revealed that the use of POFA in concretes caused delay in both initial and final setting times, depending on the fineness and degree of replacement of POFA. The compressive strength of concrete containing OP was much lower than that of Portland cement Type I concrete. Thus, OP is not suitable to be used as a pozzolanic material in concrete. However, the replacement of Portland cement Type I by 10% of MP and 20% of SP gave the compressive strengths of concrete at 90 days higher than that of concrete made from Portland cement Type I. After being immersed in 5% of magnesium sulfate solution for 364 days, the concrete bar mixed with 30% of SP had the same expansion level as that of the concrete bar made from Portland cement Type V. The above results suggest that ground POFA is an excellent pozzolanic material and can be used as a cement replacement in concrete. It is recommended that the optimum replacement levels of Portland cement Type I by MP and SP are 20% and 30%, respectively.     

Polychlorinated dibenzo-p-dioxins/furans and polychlorinated biphenyls in fresh fishes from Qiantangjiang River, China

Muscles of two species of fish collected in Qiangtangjiang River were analyzed for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). Average concentrations of total PCDD/Fs in Crucian carp and White Amur bream were 1.14-7.88 pg g(-1)ww and 1.02-8.18 pg g(-1)ww respectively. Corresponding values for PCBs were 469.36-10972 pg g(-1)ww and 364.79-4948.0 pg g(-1)ww. Average total WHO-TEQ of Crucian carp and White Amur bream from five areas ranged from 0.25 to 2.33 pg g(-1)ww and 0.30 to 1.70 pg g(-1)ww. The contamination level was compared with other studies and risk assessment was discussed.     

生活垃圾可持续化填埋

通过对中国填埋场现状分析,提出了"可持续填理"的概念.认为生活垃圾填埋场将从单纯的最终处置场所演变为填埋与中转相结合的场所.填埋场的可持续发展也将从两方面得到体现:一为垃圾降解过程及其副产品处理中以能量形式得到利用,另一方面为稳定化后的垃圾及填埋场本身空间得到再一次的利用.     

安全员素质养成杂谈

事故发生的成因非常复杂,一方面它与人的动态心理活动和行为有关,另一方面与各种物态的安全状况和企业管理总体水平相关.无论是生产组织、经营状况、工资分配、现场环境、设备及工机具配备和使用,还是企业文化建设、家庭矛盾、个人思想情绪、社会政治和经济形势动荡等,都会或多或少地影响安全生产.可见安全管理是一门涉及面极广的综合管理,必须通过渗透和强制的方法,用法律法规和安全管理的理念、原则、方法、手段去监管和影响各项管理活动,用安全操作标准去严格规范作业者的行为.     

中国交通事故与太阳黑子周期关系浅析

近年来,随着经济和交通运输业的发展,交通事故也越来越多。交通事故固然与人类的活动密切相关,但同时也受到太阳活动的影响。根据1955-2008年50多年间的太阳黑子数和中国交通事故的有关资料,用动态变化和相关系数r比较等方法对二者之间的关系进行了分析研究。结果表明:中国交通事故的发生及死亡人数与太阳黑子活动的11年周期和22年周期之间存在明显的相关关系。     

曝气池容积计算方法分析

文中对曝气池容积的计算方法———BOD5污泥负荷率法与污泥龄法进行了分析。这两种方法实质上是属于同一个公式 ,只是考虑的角度不同而引入的两个不同概念。如能将考虑的角度有机地结合 ,将使曝气池容积的设计计算更趋合理。     

莠去津对土壤过氧化氢酶活性的影响研究

研究了除草剂莠去津对土壤过氧化氢酶活性的影响。试验结果表明,莠去津浓度不同对土壤过氧化氢酶活性影响会不同,随着浓度的升高,对过氧化氢酶活性激活作用有所增强,莠去津对离体过氧化氢酶有一定的激活;336nm处的相对荧光强度不断减弱,酶分子的构象发生了变化．过氧化氢酶分子渐趋紧密。莠去津对过氧化氢酶荧光的猝灭作用主要是由于静态猝灭引起的。     

Assessing the GHG mitigation effect of the National VI Emissions Standard for light duty vehicles in China

Environmental Science and Pollution Research - Assessing the mitigation effect on greenhouse gas (GHG) reduction of the National VI Emissions Standard bears great significance in enhanced actions...     

气固再循环半干法烧结机烟气脱硫工艺中几个问题的探讨

阐述了烧结机烟气脱硫的必要性,分析了采用的主要脱硫工艺及特点,介绍了气固再循环半干法脱硫工艺(GSCA)及其技术特点。结合邯钢的运行实际,分析了该工艺存在的问题,提出了解决的办法,为该工艺的稳定高效运行提供了参考。     

Microplastic contamination in freshwater: first observation in Lake Ulansuhai,Yellow River Basin,China

Environmental Chemistry Letters - Microplastic pollution has been widely studied in the marine environment, but is much less explored in terrestrial waters, notably in China. Therefore, we studied...