铸造旧砂制备免烧砖及经济性分析

利用东风汽车公司十堰铸造基地排放的铸造旧砂制备了免烧免蒸砖,水泥加入量控制在3%以下,自然养护2 8d的抗压强度达到15MPa以上,符合蒸压灰砂国家标准(GB1194 5 - 1999)规定的优等品MU15级的要求。通过成本核算,铸造旧砂免烧砖标砖的生产成本能够控制在0 .10元块以下,具有较好的经济性。     

某通风除尘系统运行的数值分析

通过对某通风除尘系统的动态模拟分析 ,得到了该系统的真实风量 ,为排风量调节提供参考依据     

重庆市北碚区空气质量改善效果评估分析

基于2014—2020年重庆市中心城区北碚区环境监测数据及地面观测气象要素,分析了北碚区大气污染特征,利用KNN算法建立大气污染的评估模型,对空气质量改善效果进行评估。结果表明,重庆市中心城区北碚区的PM_2.5浓度逐年呈明显下降趋势,O₃浓度除夏季有一个弱的下降趋势外,其余3个季节和年平均值整体均呈上升趋势。全年以优良天气为主且呈增加趋势。O₃与气温、日照时间呈正相关,与相对湿度呈负相关性,PM_2.5与气温、降水及风速呈负相关。基于KNN算法对空气质量改善状况评估表明,减排对O₃污染平均贡献率在-4.7%左右,对PM_2.5污染平均贡献率为-52%,气象条件对O₃污染的平均贡献率在17%左右,对PM_2.5污染的平均贡献率在-7%左右。该大气污染评估模型能够有效地评估空气改善效果。     

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。     

合肥市不同下垫面降雨径流水质特征分析

通过对合肥市4种不同类型下垫面27场降雨径流和自然降雨水样中SS、COD、TN和TP水质指标的分析,探讨了草地、屋面、校内路面和校外道路降雨径流污染物历时变化规律及初期冲刷效应,比较了不同类型下垫面降雨径流和自然降雨水样中污染物浓度分布的差异,计算了场次降雨径流污染物的事件平均浓度.结果表明,不同下垫面降雨径流污染物浓度随时间变化的规律相似,且大多存在初期冲刷现象,一般在降雨初期污染物浓度较高,随着降雨历时的延长污染物浓度呈下降趋势,并趋于平稳;不同下垫面降雨径流和自然降雨水样中TN污染负荷较高,大气湿沉降对降雨径流中TN的贡献很大;校外道路降雨径流水样中SS、COD、TN和TP浓度的变化范围冬半年大于夏半年,不同下垫面条件对降雨径流中污染物EMC的影响存在差异.     

不同天气系统影响下广东省酸雨特征对比分析 ——气象场数值模拟

运用WRF模式对3种不同天气系统(冷锋,低压槽以及台风)造成的广东省酸雨个例进行数值模拟,结合实际测站资料对酸雨分布特征及影响酸雨过程的风场、湿度场以及温度场进行分析.结果表明个例中酸雨主要分布在珠江三角洲区域以及重工业区韶关.不同天气系统影响下的降水酸度略有不同,台风个例降水pH值最高(5.81),其后依次为低压槽降水(5.60)及冷锋降水(5.40). 冷锋降水个例中酸雨的分布及变化主要受风速,风向,相对湿度及逆温的影响,低压槽和台风降水个例中的酸雨分布及变化主要受降水量和风速的影响.风速和降水量的增加有利于缓解降水的酸度,而逆温层的存在及不同风向的辐合作用有利于降水酸度的增加.     

Isolation and identification of a bioflocculant-producing strain and optimisation of cultural conditions via a response surface model

A bioflocculant-producing strain named MY6-2 was isolated from a mixed activated sludge by a nitrogen-free medium. Based on 16S rDNA sequence, biochemical and morphological characteristics, the strain MY6-2 was identified as Bacillus mucilaginosus. The chemical analysis indicated that the flocculant MY6-2 was mainly composed of extracellular polysaccharide. The result of the composition of the medium showed that MY6-2 was able to generate bioflocculant in a nutrient-poor medium that consisted of 5?g?L^?1 sucrose and no nitrogen source. Response surface methodology (RSM) was used to optimise the fermentation condition of MY6-2 for maximum flocculating activity by using central composite design (CCD). Based on the result, the optimum conditions were as follows: 100?mL of broth in a 250?mL Erlenmeyer flask, initial pH 8.0 and inoculum concentration 10%, respectively. The highest flocculating rate of 90% was achieved under these conditions by adding 0.5?mL fermentation supernatant to 95?mL of Kaolin suspension.     

A compass for sustainable development

A response to the Nuffield Council on Bioethics Consultation from the Institute of Biology, the Association of Applied Biology, the British Crop Protection Council, the British Ecological Society, the British Electrophoresis Society, the British Grassland Society, and the Institute of Horticulture     

弱酸性条件下丙酸富集培养物的降解特性

为阐明厌氧生物处理系统中pH降低对丙酸降解的影响,考察了弱酸性条件下丙酸富集培养物的降解特征.在污泥接种量为0.22g MLVSS/L,初始丙酸浓度为1000mg/L条件下,对照组（pH7.0）的丙酸能够被该富集培养物快速降解,在接种第6d时,丙酸去除率达到了98.5%.当pH从7.0分别降低至6.5和6.0时,丙酸降解速度立即下降.但经过2~3d的适应后,丙酸降解速率恢复到对照的水平,并分别在培养至第8d和9d时其去除率达到了97%以上.当pH为5.5时,丙酸降解被完全抑制.在整个实验过程中,均未检测到氢气,而乙酸也只有在培养初期有过短暂的积累.该结果表明,在该丙酸富集培养物中,产甲烷菌对弱酸性环境具有更好的耐受性和适应性.     

Operating mechanism and set pair analysis model of a sustainable water resources system

There is no alternative to the world’s water resources, and their increasing scarcity is making it difficult to meet the world population’s water needs. This paper presents a sustainable water resources system (SWRS) and analyzes the operating mechanism that makes it possible to evaluate the status of such a system. A SWRS can be described as a complex coupling system that integrates water resources, social, economic and ecological systems into a whole. The SWRS’s operating mechanism is composed of dynamic, resistance and coordination components, and it interacts with and controls the system’s evolution process. The study introduces a new approach, set pair analysis theory, to measure the state of a SWRS, and an evaluation index system is established using the subsystems and operating mechanism of a SWRS. The evaluation index system is separated into three levels (goal level, criteria level and index level) and divides the index standard into five grades. An evaluation model of the SWRS based on set pair analysis theory is constructed, and an example of SWRS evaluation in Shanghai is presented. The connection degrees of the index in the three levels are calculated, and the connection degree of the goal index is calculated to be 0.342, which classifies the city’s SWRS condition as grade 2. The sustainable use of water resources in the region is determined to be at a relatively adequate level that meets the requirements of sustainable development.