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91.
为了研究动态推进过程中工作面推进距离对采空区煤自燃分布特征的影响,采取及时有效的煤自燃防治措施,以13210综放面为工程背景,基于采空区渗透率分布公式和传热传质控制方程,建立采空区煤自燃数值解算模型。利用COMSOL软件模拟了工作面不同推进距离下以流速和氧体积分数为划分指标的采空区氧化带范围和高温区域的变化规律,分析了高温区域与氧化带的叠加效应。通过现场实测与模拟结果比对,验证了模拟的准确性。研究结果表明:采空区渗透率随着工作面推进距离的增加而不断变化,近工作面端渗透率变化不大,而中深部采空区的渗透率不断减小;采空区氧化带分布随工作面推进距离的增加呈现阶段性变化特征,推进初期氧化带范围不断变化,推进后期氧化带范围趋于稳定;采空区氧化带分布与高温区域重叠深度随工作面推进不断增加,最终稳定于工作面后方60~70 m范围内。 相似文献
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针对活性污泥法处理乳品工业废水过程中产生大量活性污泥的现状,研究不同温度、pH和沉降时间对活性污泥沉降的影响,旨在阐明活性污泥沉降性能的最佳条件,最大限度降低活性污泥在污水处理系统中所占的体积。试验结果表明当污泥沉降时间为120 m in时,pH6.0,35℃条件下污泥沉降体积为54%;pH7.0,45℃条件下污泥沉降比为54%;pH8.0,45℃污泥沉降体积比为55%;pH9.0,55℃条件下污泥沉降体积为52%;pH 10.0,5℃、15℃、25℃、35℃、45℃和55℃条件下污泥沉降体积比相近,均在60%以上。结合乳品废水处理的实际情况,pH6.0~9.0,温度35℃~55℃,污泥沉降时间为120 m in,污泥沉降效果较好,体积比可达到52%~54%。 相似文献
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作为洞庭湖一级支流,澧水对洞庭湖乃至长江水系鱼类资源的维持或补充有着重要作用。为了了解澧水的鱼类资源现状,于2010年4月~2011年12月,对湖南境内澧水水系鱼类资源进行调查。共采集鉴定鱼类95种(包括1种湖南鱼类新纪录,4种外来种),隶属于8目19科59属。种类组成以鲤科鱼类为主,占5053%。多样性分析表明,澧水不同江段鱼类群落多样性处于较好或丰富状态,在空间分布上,鱼类物种数按上、中、下游依次增加,多样性指数也呈上升趋势且差异显著(P<005)。相似性及聚类分析表明,澧水鱼类群落可分为3个类群,即:上、中、下游类群;上游与中游类群为中等相似,与下游类群为中等不相似,中游与下游类群相似性总体小于与上游类群相似性。澧水鱼类在洄游、摄食、栖息习性等生态类型上呈现多样化特征。调查江段渔获物组成虽存在差异,但主要以鲤、鲫、翘嘴鲌、蒙古鲌、鲇、黄颡鱼、[XCz1.tif;%85%85,JZ]、银鮈、中华花鳅、子陵吻鰕虎鱼等湖泊定居性或山溪流水性[JP3]鱼类为主,“四大家鱼”等洄游性鱼类所占比例极低,鱼类小型化现象明显,原因分析主要与水工建设和过度捕捞有关。[ 相似文献
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环境类高等职业教育具有鲜明的非行业背景和人才需求领域广泛而应用岗位相对集中的特殊性。在对国内部分环境类高职院校和环境类高职专业就产学研用合作机制及运行模式实地调研的基础上,对现存的环境类高职院校产学研用合作模式进行了深入分析,提出了"依托政府,实施‘双轨并行’工学结合"的产学研用合作机制与运行模式。 相似文献
98.
Hailong Li Øivind Wilhelmsen Yuexia Lv Weilong Wang Jinyue Yan 《International Journal of Greenhouse Gas Control》2011,5(5):1119-1139
Accurate experimental data on the thermo-physical properties of CO2-mixtures are pre-requisites for development of more accurate models and hence, more precise design of CO2 capture and storage (CCS) processes. A literature survey was conducted on both the available experimental data and the theoretical models associated with the transport properties of CO2-mixtures within the operation windows of CCS. Gaps were identified between the available knowledge and requirements of the system design and operation. For the experimental gas-phase measurements, there are no available data about any transport properties of CO2/H2S, CO2/COS and CO2/NH3; and except for CO2/H2O(/NaCl) and CO2/amine/H2O mixtures, there are no available measurements regarding the transport properties of any liquid-phase mixtures. In the prediction of gas-phase viscosities using Chapman–Enskog theory, deviations are typically <2% at atmospheric pressure and moderate temperatures. The deviations increase with increasing temperatures and pressures. Using both the Rigorous Kinetic Theory (RKT) and empirical models in the prediction of gas-phase thermal conductivities, typical deviations are 2.2–9%. Comparison of popular empirical models for estimation of gas-phase diffusion coefficients with newer experimental data for CO2/H2O shows deviations of up to 20%. For many mixtures relevant for CCS, the diffusion coefficient models based on the RKT show predictions within the experimental uncertainty. Typical reported deviations of the CO2/H2O system using empirical models are below 3% for the viscosity and the thermal conductivity and between 5 and 20% for the diffusion coefficients. The research community knows little about the effect of other impurities in liquid CO2 than water, and this is an important area to focus in future work. 相似文献
99.
Once contaminate the drinking water source, antibiotic resistance genes (ARGs) will propagate in drinking water systems and pose a serious risk to human health. Therefore, the drinking water treatment processes (DWTPs) are critical to manage the risks posed by ARGs. This study summarizes the prevalence of ARGs in raw water sources and treated drinking water worldwide. In addition, the removal efficiency of ARGs and related mechanisms by different DWTPs are reviewed. Abiotic and biotic factors that affect ARGs elimination are also discussed. The data on presence of ARGs in drinking water help come to the conclusion that ARGs pollution is prevalent and deserves a high priority. Generally, DWTPs indeed achieve ARGs removal, but some biological treatment processes such as biological activated carbon filtration may promote antibiotic resistance due to the enrichment of ARGs in the biofilm. The finding that disinfection and membrane filtration are superior to other DWTPs adds weight to the advice that DWTPs should adopt multiple disinfection barriers, as well as keep sufficient chlorine residuals to inhibit re-growth of ARGs during subsequent distribution. Mechanistically, DWTPs obtain direct and inderect ARGs reduction through DNA damage and interception of host bacterias of ARGs. Thus, escaping of intracellular ARGs to extracellular environment, induced by DWTPs, should be advoided. This review provides the theoretical support for developping efficient reduction technologies of ARGs. Future study should focus on ARGs controlling in terms of transmissibility or persistence through DWTPs due to their biological related nature and ubiquitous presence of biofilm in the treatment unit. 相似文献
100.
Kong Hui Du Chuan-ming Lv Ning-ning Yu Yao-hui 《Journal of Material Cycles and Waste Management》2022,24(1):259-267
Journal of Material Cycles and Waste Management - Dephosphorization slag is primarily composed of CaO–SiO2–FeO–P2O5 slag system. As it contains abundant valuable components,... 相似文献