非柔性连接石化储罐配管温差应力分析与对策

储罐配管在温差作用下产生热位移会导致管壁产生热应力，未采用柔性连接的配管由于热应力集中作用可能发生破漏。针对与石油化工储罐非柔性连接的配管的安全问题，应用ANSYS有限元分析软件模拟计算石化企业典型配管的热应力分布；根据不同类型配管的分析结果，提出了工程技术与管理方面的针对性安全措施。研究结果表明:温差效应对石化储罐配管热应力影响显著，随内外温差的增加，配管应力集中的区域增大，最大热应力值增大；补偿措施能够改善配管的柔性，降低配管应力；约束载荷限制配管热膨胀从而增大配管应力；三通管是多根配管接合的区域，这种复杂管道交汇处会形成明显应力集中。研究结果对于提高石油化工非柔性连接配管安全性有一定的指导意义。     

水生态环境质量评价体系研究

流域水生态环境质量评价体系是为流域环境管理提供基础数据,协助管理者开展流域保护措施的重要技术支持。该文深入剖析了发达国家典型水生态环境质量评价体系,归纳分析了其体系框架、构成特点、方法适用性和借鉴意义。结合前期研究基础,对评价体系的技术内容进行了完善和补充,明确了参照点位的选择原则,补充了评价方法选择的技术路线,提出了增设和实施不同监测计划的方案,最终提出生态环境质量评价技术体系框架。     

三峡库区消落带农用坡地磷素径流流失特征

消落带是三峡库区重要的生态交错带，但自发农用和无序开发可能会造成更多的氮磷流失，进而加剧三峡库区水体富营养化。通过对库区连续3 a的定位监测（2011~2013年），研究了三峡库区消落带农用坡地的磷素流失特征。结果表明：次降雨事件中常规施肥处理的地表径流、壤中流总磷平均浓度分别为0.848±0.153、0.140±0.006 mg/L，其中地表径流中磷的形态以颗粒态为主，壤中流以溶解态的生物可利用磷为主。常规施肥下，地表径流、壤中流磷素年均流失通量分别为0.236±0.004、0.100±0.003 kg·hm 2，地表径流、壤中流磷素流失通量分别占总流失通量的70.2%、29.8%，地表径流是坡地磷素流失的主要途径，但壤中流也是不可忽视的重要途径。与常规施肥处理相比，减量施肥处理地表径流、壤中流磷素流失量分别降低了45.3%、40.0%。建议采取减量施肥的方式，以降低营养盐负荷，保护水环境。     

The regulatory role of endogenous iron on greenhouse gas emissions under intensive nitrogen fertilization in subtropical soils of China

Environmental Science and Pollution Research - Anaerobic batch experiments were conducted to study the regulatory role of endogenous iron in greenhouse gas emissions under intensive nitrogen...     

Study of the adsorption of endocrine disruptor compounds on typical filter materials using a quartz crystal microbalance

Environmental Science and Pollution Research - Drinking water containing environmental endocrine disruptor compounds (EDCs) endangers human health, and researching the purification process of...     

Growth of Zostera japonica in different sediment habitats of the Yellow River estuary in China

Environmental Science and Pollution Research - The estuarine delta of the Yellow River is a region of strong land-ocean-human interactions that undergoes a unique evolutionary process. The delta is...     

天津市地表水体与沉积物中7种高关注酚类化合物的污染特征与生态风险分析

为探究地表水体与沉积物中酚类化合物的污染分布特征和生态风险,选择天津市3个水源地与6条主要河流,采集了26个地表水样与6个沉积物样品,利用固相萃取与超声萃取、高效液相色谱-串联质谱法(HPLC-MS/MS)测定了水样及沉积物中1-萘酚(1-naphthol)、壬基酚(nonylphenol, NP)、双酚A(bisphenol A, BPA)、2-苯基苯酚(biphenyl-2-ol)、3,4-二氯酚(3,4-dichlorophenol)、四溴双酚A(tetrabromobisphenol A, TBBPA)和对叔丁基苯酚(p-tert-butylphenol, PTBP)等7种高关注酚类化合物的浓度水平,并应用物种敏感性分布(species sensitivity distribution, SSD)法和熵值法(ecological risk quotient, RQ)评估7种酚类化合物水环境和沉积物的生态风险。结果表明,地表水样中7种酚类化合物均全部检出;其中壬基酚的检出浓度最高,其次为四溴双酚A、对叔丁基苯酚、1-萘酚、2-苯基苯酚、3,4-二氯酚和双酚A。沉积物中酚类化合物的污染分布规律与水样相似,除双酚A外的目标物全部检出。其中,壬基酚浓度比其他物质浓度高2个数量级。风险评估结果显示,壬基酚对水环境与沉积物存在不可接受的风险;而四溴双酚A、对叔丁基苯酚、1-萘酚、2-苯基苯酚、3,4-二氯酚和双酚A则对环境具有较低风险或者存在一定的风险。     

Biofiltration and disinfection codetermine the bacterial antibiotic resistome in drinking water: A review and meta-analysis

• Published data was used to analyze the fate of ARGs in water treatment. • Biomass removal leads to the reduction in absolute abundance of ARGs. • Mechanism that filter biofilm maintain ARB/ARGs was summarized. • Potential BAR risks caused by biofiltration and chlorination were proposed. The bacterial antibiotic resistome (BAR) is one of the most serious contemporary medical challenges. The BAR problem in drinking water is receiving growing attention. In this study, we focused on the distribution, changes, and health risks of the BAR throughout the drinking water treatment system. We extracted the antibiotic resistance gene (ARG) data from recent publications and analyzed ARG profiles based on diversity, absolute abundance, and relative abundance. The absolute abundance of ARG was found to decrease with water treatment processes and was positively correlated with the abundance of 16S rRNA (r² = 0.963, p<0.001), indicating that the reduction of ARG concentration was accompanied by decreasing biomass. Among treatment processes, biofiltration and chlorination were discovered to play important roles in shaping the bacterial antibiotic resistome. Chlorination exhibited positive effects in controlling the diversity of ARG, while biofiltration, especially granular activated carbon filtration, increased the diversity of ARG. Both biofiltration and chlorination altered the structure of the resistome by affecting relative ARG abundance. In addition, we analyzed the mechanism behind the impact of biofiltration and chlorination on the bacterial antibiotic resistome. By intercepting influent ARG-carrying bacteria, biofilters can enrich various ARGs and maintain ARGs in biofilm. Chlorination further selects bacteria co-resistant to chlorine and antibiotics. Finally, we proposed the BAR health risks caused by biofiltration and chlorination in water treatment. To reduce potential BAR risk in drinking water, membrane filtration technology and water boiling are recommended at the point of use.     

玛纳斯河流域荒漠草地沙化遥感监测研究

以1989—2016年玛纳斯河流域TM/OLI遥感影像为数据源,利用混合像元分解技术,计算玛纳斯河流域草地总覆盖度和裸沙面积。在此基础上通过监测年与基期年的比较,计算草地覆盖度相对基期年的减少率和裸沙面积相对基期年的增加率两个监测指标,依据《天然草地退化、沙化、盐渍化的分级指标》(GB 19377—2003),对计算出的两个指标分别进行沙化等级评定和赋值,将两种评定结果相综合来监测草地沙化。结果表明,玛纳斯河流域近30年来荒漠草地沙漠化总体呈现先增加后降低的趋势。分析表明,玛纳斯河流域草地沙化是人为和自然因素双重作用的结果。     

Quantification of nitrogen in the liquid fraction and in vitro assessment of lysine bioavailability in the solid fraction of soybean meal hydrolysates

Soybean meal (SBM) is a product generated from the manufacture of soybean oil and has the potential for use as a source of fermentable sugars for ethanol production or as a protein source for animal feeds. Knowing the levels of nitrogen available from ammonium is a necessary element of the ethanolic fermentation process while identifying the levels of essential amino acids such as lysine is important in determining usage as a feed source. As such the purpose of this study was to quantify total nitrogen and ammonium in the liquid fraction of hydrolyzed SBM and to evaluate total and bioavailable lysine in the solid fraction of the hydrolyzed SBM. The effects of acid concentration, cellulase and β-glucosidase on total and ammonium nitrogen were studied with analysis indicating that higher acid concentrations increased nitrogen compounds with ammonium concentrations ranging from 0.20 to 1.24 g L^?1 while enzymatic treatments did not significantly increase nitrogen levels. Total and bioavailable lysine was quantified by use of an auxotrophic gfpmut3 E.coli whole-cell bioassay organism incapable of lysine biosynthesis. Acid and enzymatic treatments were applied with lysine bioavailability increasing from a base of 82% for untreated SBM to up to 97%. Our results demonstrated that SBM has the potential to serve in ethanolic fermentation and as an optimal source essential amino acid lysine.