钢筋混凝土梁裂缝宽度的有限元分析

文章根据所做试验情况,对钢筋混凝土梁的裂缝宽度进行了有限元模拟.有限元分析结果与试验结果吻合良好.说明有限元分析在某种程度上可以代替试验对钢筋混凝土梁裂缝宽度进行研究分析.     

水体中氨氮测定方法的比较——纳氏试剂光度法、靛酚蓝比色法

纳氏试剂光度法是氨氮的经典测定方法,但该方法的灵敏度不高。靛酚蓝比色法对氨氮具有特殊的敏感性和相关性,具有较高的准确度、精确度和敏感度。同时用两种方法对水样进行了测定,结果显示无显著性差异,但是靛酚蓝比色法较为方便,准确,易于操作,极大地减轻了分析人员的劳动强度,具有积极的现实意义。     

嘉兴市环境库兹涅茨曲线特征分析

环境库兹涅茨曲线(EKC)暗含了对经济增长和环境之间的发展战略。运用EKC理论模型,对嘉兴市工业"三废"排放量与人均GDP之间关系进行分析,发现工业废水、工业废气、工业固体废弃物排放量与人均GDP之间的关系分别为N型、倒U型左侧上升阶段、倒U型左侧接近拐点,表明嘉兴市经济增长还处在加重环境负担的阶段,还未实现环境与经济的协调发展。引起工业废水、工业废气排放量居高不下的原因分别是嘉兴市产业结构特点和能源结构特点。建议优化产业结构,调整能源结构,推进循环经济发展,争取早日跨越环境库兹涅茨曲线拐点,实现环境经济的协调发展。     

上海市电子废物处理企业的环境管理实践

电子产品和家用电器的更新换代使得废弃电子电器成为城市新的污染源,危害着城市环境和人体健康。本文介绍了电子废弃物的定义、环境危害、回收利用价值及增长趋势,重点阐述了上海市废旧家电拆解企业的现状,并针对企业具体情况提出相应的管理对策。依法加强电子废物的环境管理,对促进循环经济的发展具有重要意义。     

剪切失效型钢筋混凝土柱滞回模型参数识别与经验预测∗

在我国中低抗震设防烈度地区的既有钢筋混凝土结构中,有很大一部分既有钢筋混凝土柱在地震作用下容易发生剪切破坏,失去竖向承载力,导致既有建筑发生倒塌,造成严重的经济损失和人员伤亡。一个简单、高效的滞回模型对剪切失效型既有钢筋混凝土柱的抗震性能评估具有重要意义。首先提出了一个简化的七参数折线型滞回模型,然后基于SERIES数据库中的剪切失效型钢筋混凝土柱试验结果,采用微分进化算法,对七参数折线型滞回模型进行了参数识别。最后,采用经验回归分析方法,提出了七参数折线型滞回模型中关键参数的经验预测方程。结果表明:给定设计参数,提出的七参数折线型滞回模型可以方便、快速地预测剪切失效型钢筋混凝土柱的恢复力-位移关系,便于工程应用。     

Characterization of the e ective cellulose degrading strain CTL-6

An e cient cellulose degrading bacteria exists in the thermophilic wheat straw-degrading community, WDC2. However, this strain cannot be isolated and cultured using conventional separation techniques under strict anaerobic conditions. We successfully isolated a strain of e ective cellulose degrading bacteria CTL-6 using a wash, heat shock, and solid-liquid alternating process. Analysis of its properties revealed that, although the community containing the strain CTL-6 grew under aerobic conditions, the purified strain CTL-6 only grew under anaerobic culture conditions. The strain CTL-6 had a striking capability of degrading cellulose (80.9% weight loss after 9 days of culture). The highest e ciency value of the endocellulase (CMCase activity) was 0.404 mol/(min mL), cellulose degradation e ciency by CTL-6 was remarkably high at 50–65°C with the highest degradation e ciency observed at 60°C. The 16S rRNA gene sequence analysis indicated that the closest relative to strain CTL-6 belonged to the genus Clostridium thermocellum. Strain CTL-6 was capable of utilizing cellulose, cellobiose, and glucose. Strain CTL-6 also grew with Sorbitol as the sole carbon source, whereas C. thermocellum is unable to do so.     

Denitrification of coking wastewater with micro-electrolysis

The denitrification for the coking wastewater was conducted by means of original battery principle with Fe-C micro-electrolysis. Fe-C serves as positive and negative electrodes, by which N0₂^?-N and TN were reduced to nitrogen, and then the purpose of denitrifieation for coking wastewater was realized. The influences of pH value, carbon particle size, Fe/C ratio (mass ratio), reaction time and coagulation pH value on removal rate of N0₂^?-N and TN were investigated. Coking wastewater originated from Jiamusi Coal Chemistry Engineering Company. The optimum conditions of treatment were as follows: the initial pH was 3.0, the dosage of Fe 73.5 g/L, reaction time 70 min, mass ratio of Fe/C ratio 1.0:1.3, coagulation pH 9.0 and sedimentation time 40 min. Under those conditions, nitrogen removal efficiencies of N0₂^?-N and TN were beyond 50% and 45%, respectively.     

Macroscale and microscale analysis of Anammox in anaerobic rotating biological contactor

Inoculated with conventional anaerobic activated sludge, the Anammox process was successfully developed in an anaerobic rotating biological contactor (AnRBC) fed with a low ratio of C/N synthetic wastewater. Operated in a single point feed mode, the AnRBC removed 92.1% (n = 126) of the influent N at the highest surface load of 12 g/(m².day). The biomass increased by 25% and 17.1 g/(m².day) of maximum N removal surface load was achieved by elevating flow rate with another feed point. Fluorescence in situ hybridization and polymerase chain reaction analysis indicated that the Anammox genus Candidatus Kuenenia stuttgartiensis dominated the community. Both Anammox and denitrifying activity were detected in biofilm by the application of microelectrodes. In the outer layer of the biofilm (0-2500 μupm), nitrite and ammonium consumed simultaneously in a ratio of 1.12/1, revealing the occurrence of Anammox. In the inner layer (> 2500 μupm), a decrease of nitrate was caused by denitrification in the absence of nitrite and ammonium.     

硫磺安全仓储关键技术

介绍了硫磺火灾爆炸机理,并对硫磺仓储系统的危险性进行了分析。结合相关实验数据,提出了仓库设计、工艺运行、事故预防中的安全措施,以保证硫磺散装系统能够安全、长周期平稳运行。     

川东北地区天然气勘探清洁生产技术措施分析

对川东北地区天然气勘探过程中的几项清洁生产技术措施进行了初步的分析,确定在取得良好的经济效益的同时,实现勘探过程中废弃物"减量化、无害化、资源化"的清洁生产目标,降低了勘探过程中的环境风险,同时也产生了良好的社会效益。