Removal of copper ions and dissolved phenol from water using micellar-enhanced ultrafiltration with mixed surfactants

A laboratory study was conducted to evaluate the effects of composition and concentration of mixed anionic/nonionic surfactants on the efficiency of a micellar-enhanced ultrafiltration (MEUF) operation in removing metal ions/organic solutes from aqueous solutions. Based on the analysis of surface tensions and micelle sizes, it was found that for mixed sodium dodecylsulfate (SDS)/Triton X-100 surfactants, the critical micelle concentration (cmc) was significantly lower than that of SDS and mixed micelles formed. The mixed surfactant system was then applied in a cross-flow mode of MEUF, in which the concentration polarization can be neglected, to remove Cu2+ from aqueous solutions. With a surfactant concentration of 10 mM, the Cu2+ rejection was negligible by using pure Triton X-100 and increased with increasing SDS mole fraction with a value as high as 85%, which suggests that the rejection of Cu2+ was due to the electrostatic attraction between Cu2+ and SDS. Furthermore, pronounced Cu2+ rejection was obtained for a 5 mM SDS solution, which was attributable to a decrease in the cmc of SDS by the existence of Cu2+. When the MEUF technique was applied to remove Cu2+ and phenol simultaneously from aqueous solutions, the Cu2+ rejection was slightly enhanced in the presence of phenol. However, the rejection of phenol was comparatively low, approximately 27%, which may be caused by its relatively hydrophilic characteristic.     

开发基于GIS的城市防震减灾信息系统 --组件对象模型的应用

应用GIS建立城市防震成灾信息系统是一条减轻城市地震灾害的有效途径,而现有的城市防震减灾信息系统中防震减灾专业模型与GIS功能结合不够紧密,因此加强对地震灾害智能计算的研究十分重要。文章分析了城市防震成灾信息系统常用的二次开发方法,阐述了组件对象模型(COM)技术及其在系统开发中的应用方法,论述了应用COM技术开发系统的界面与功能等。     

废钻井液固化实验研究

利用经实验筛选的固化剂配方对废钻井液进行了固化处理的室内配方研究。结果表明,经该固化剂配方处理后的固结材料在水中浸泡5d后的浸出液在色度、化学需氧量、pH值、石油类、悬浮物含量和重金属含量等指标方面可达到国家《污水综合排放标准》(GB8978-1996)中的二级标准。     

企业资源管理拓展问题评述

企业资源管理问题是关系到提升企业核心价值和保持企业持续竞争优势的重要问题，企业资源管理的拓展是企业管理理论和实践的共同需要。在文献综述的基础上，从企业广义资源环境划分、企业资源管理范畴拓展、企业资源形式和属性等几个不同角度，对企业资源管理拓展问题进行了讨论和分析。     

轴心受压钢筋混凝土柱等效火灾荷载的计算

迄今为止，国内外有关计算构件耐火极限的方法，是钢筋混凝土构件与防火研究的主要内容。而在结构设计中，由于直接考虑的是荷载作用，为此提出了一个新概念——等效火灾荷载，将火灾对结构的影响直接考虑成荷载作用。在确定了混凝土柱的截面温度场后，利用一种简化计算方法计算出钢筋混凝土柱的等效火灾荷载，进而计算出钢筋混凝土柱的耐火极限。在火灾中，作为结构最基本的构件柱可能受到单面或多面的火作用，这里仅介绍轴心受压钢筋混凝土柱等效火灾荷载的计算。     

US/Fenton试剂协同处理焦化废水的研究

采用US (超声波)协同Fenton试剂氧化法处理焦化废水,考察了H2O2投加量、Fe2 投加量、废水的pH、反应时间和超声波功率对处理效果的影响,确定了最佳工艺条件.结果表明,在H2O2投加量7.0 g/L;Fe2 投加量500 mg/L;pH=3.0; 反应时间 40 min; 超声波功率 600 W 的条件下,COD、NH3-N、CN-和色度的去除率分别达95.8%、71.3%、69.5%和75.2%,出水COD降至41.0 mg/L.在相同条件下,US/Fenton试剂协同法的处理效率比单独Fenton试剂氧化法的处理效率提高了约20%,且反应时间显著缩短.     

The fragmentation patterns of maternal plasma cell-free DNA and its applications in non-invasive prenatal testing

The discovery of cell-free DNA (cfDNA) in maternal plasma has opened up new promises for the development of non-invasive prenatal testing (NIPT). Application of cfDNA in NIPT of fetus diseases and abnormalities is restricted by the low amount of fetal DNA molecules in maternal plasma. Fetus-derived cfDNA in maternal plasma are shorter than maternal DNA, thus leveraging the maternal and fetus-derived cfDNA molecules size difference has become a novel and more accurate method for NIPT. However, multiple biological properties such as size distribution of plasma DNA, proportion of fetal-derived DNA and methylation levels in maternal plasma across different gestational ages still remain largely unknown. Further insights into the size distribution and fragmentation pattern of circulating plasma cfDNA will shed light on the origin and fragmentation mechanisms of cfDNA during physiological and pathological processes in prenatal diseases and enhance our ability to take the advantage of plasma cfDNA as a molecular diagnostic tool. In the review, we start by summarizing the research techniques for the determination of the fragmentation profiles of cfDNA in maternal plasma. We then summarize the main progress and findings in size profiles of maternal plasma cfDNA and cffDNA. Finally, we discuss the potential diagnostic applications of plasma cfDNA size profiling.     

Regulating the hydrolysis of organic wastes by micro-aeration and effluent recirculation

In this study, the effects of micro-aeration and liquid recirculation on the hydrolysis of vegetable and flower wastes during two-phase solid–liquid anaerobic digestion were assessed. To accomplish this, we evaluated the hydrolysis of five batches of waste that were treated under the following conditions: anaerobic, insufficient micro-aeration (aeration for 5 min every 24 h), and sufficient micro-aeration (aeration for 5 min every 12, 4 and 1 h). Hydrolysis was found to depend on the level of micro-aeration. Specifically, insufficient micro-aeration led to unstable and decreased performance. Conversely, sufficient micro-aeration promoted the hydrolysis of easily biodegradable carbohydrates and proteins, but the microbial activity was later impaired by liquid recirculation using methanogenic effluent. The hydrolysis efficiency under anaerobic conditions was comparable to the efficiency observed under sufficient micro-aeration, while the cumulative TOC of the anaerobic batch was 1.4–2.4 times higher than that of the micro-aerated batches. In addition, liquid recirculation did not have a negative effect on the development of microbial activity under anaerobic conditions, which resulted in the lignocelluloses having a higher hydrolysis efficiency.