水解酸化+接触氧化处理水产品加工废水

通过工艺对比,采用"水解酸化+接触氧化"工艺处理水产品加工废水,运行结果表明,出水COD为320.3 mg/L,BOD5为155.4 mg/L,去除率分别达到84.1%和84.6%,达到《污水综合排放标准》(GB8978-1996)三级排放标准及《污水排入城市下水道水质标准》CJ3082-1999标准要求。     

液氯消毒和紫外线消毒在实践中的应用比较

为了有效保护水体,防止传染性病原菌对人们的危害,降低水源的总大肠菌群数和粪大肠菌群数,对污水处理厂出水进行消毒是十分必要的,文章通过介绍液氯消毒和紫外线消毒,并针对这两种消毒方式在广州污水厂的应用实践的比较,提出对于污水处理厂出水消毒的建议。     

不同类型水生植物在人工湿地中的净化效果研究进展

人工湿地作为污水的深度处理系统,因其处理效果好、运行费用低等优势得到国内外广泛应用。文章介绍了人工瀑地的优越性与水生植物的作用原理,综述了挺水植物、浮水植物和沉水植物在国内外的净化效果研究实践,讨论了各类型水生植物在人工湿地建设中的适用性,指出目前的研究不足之处。     

草鱼腐败菌Pseudomonas putida和Shewanella putrefaciens互作对其致腐能力的影响

草鱼贮藏期间易由于微生物的生长繁殖发生腐败变质,一定程度上制约了其加工产业的发展。微生物互作是影响食品腐败的重要因素,为探究微生物互作在草鱼品质劣变中的作用,将Pseudomonas putida(P. putida)和Shewanella putrefaciens(S. putrefaciens)混合接种至草鱼鱼肉和精氨酸溶液中,通过测定鱼肉贮藏期间菌落总数、可溶性肽、游离氨和腐胺等指标的变化,以及精氨酸溶液中的腐胺产量,揭示草鱼腐败微生物P. putida和S. putrefaciens互作效应对这2种菌生长和致腐能力的影响。结果表明,P. putida具有较强的产嗜铁素能力,并通过竞争三价铁离子抑制了鱼肉中S. putrefaciens的生长。P. putida和S. putrefaciens互作升高了贮藏前11d鱼肉中游离氨和贮藏前8d鱼肉中腐胺的含量,但对鱼肉中可溶性肽的生成没有促进作用。贮藏11d后,由于S. putrefaciens的生长受到抑制,P. putida和S. putrefaciens没有通过互作效应促进游离氨和腐胺的产生。P. putida可以通过精氨酸脱亚胺酶途径为S. putrefaciens提供精氨酸降解产物,从而增强S. putrefaciens产腐胺的能力。整体来说,P. putida和S. putrefaciens在贮藏期(0～11d)内会通过代谢共栖等菌间互作效应增强致腐能力,并加速草鱼理化指标劣变。S. putrefaciens在草鱼腐败及2种微生物间的互作效应中起基础作用,今后在鱼肉贮藏保鲜技术开发中应注重对S. putrefaciens的控制研究。     

Direct characterisation of phenolic antioxidants in infusions from four Mapuche medicinal plants by liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS)

A simple, fast and direct method was developed for the qualitative analysis of phenolic constituents from infusions of Mapuche medicinal plants. Teas made of Linum chamissonis Schiede, Quinchamalium chilensis Mol., Adesmia emarginata Clos. and Escallonia illinita K. Presl. were analysed by high-performance liquid chromatography with diode array detector (HPLC-DAD) and electrospray mass spectrometry (ESI-MS). This technique allowed for the first time the tentative identification of 16 phenolic compounds in E. illinita, 27 in Q. chilensis, 10 in L. chamissonis and 19 in A. emarginata. The compounds were mainly phenolic acids, flavonoid glycosides, anthocyanins and tannins. The total phenolic and flavonoid content of the infusions was assessed as well as the free radical scavenging capacity measured by the bleaching of a solution of the 2,2-diphenyl-1-picrylhydrazyl (DPPH⁻) radical. From the four species, Q. chilensis exhibited the strongest antioxidant activity with highest total phenolic and flavonoid content.     

Alarm management practices in natural gas processing plants

In industrial data sets, groups of variables often move together. Monitoring all these variables may result in many nuisance alarms. However, it is possible to take advantage of redundant information to design and reduce the size of alarm sets. The present work reports the application of an alarm management protocol based on alarm priorization to three large Natural Gas Processing Plants, during a three year period, and also investigates the use of different correlation analyses techniques as tools to assist in the further reduction of the number of alarms. The results show that the adopted practices enable the reduction of alarms.     

Long-term hygrothermal performance of nuclear reactor concrete containments – Laboratory evaluations of measurement setup,in situ sampling,and moisture flux calculations

A measurement setup for in situ sampling of internal relative humidity and temperature in concrete structures was developed. The setup was used to evaluate the moisture conditions and to determine whether drying of the concrete components within a nuclear reactor containment contributes to the moisture conditions. The measurement setup was tested for accuracy and thereafter installed in Swedish nuclear reactor containments for in situ monitoring. Results from the measurements confirmed that the setup is suitable, especially for long-term measurements at depths of 50 mm or more. Complementary moisture transport calculations showed that the moisture flux from the concrete to the interior of the reactor containment have a noticeable effect on the environmental conditions in the containments. The calculations of the moisture condition in the concrete show that 15–30% of the evaporable water in the concrete has been dried out during the 30 years of operation.     

Viscosity virtual sensor to control combustion in fossil fuel power plants

Thermo-electrical power plants utilize fossil fuel oil to transform the calorific power of fuel into electric power. An optimal combustion in the boiler requires the fuel oil to be in its best conditions. One of fuel's most important properties to consider is viscosity. Viscosity has influence on the optimal combustion between fuel and air. Hardware viscosity meters for fuel oils are expensive and unreliable to operate in power plant conditions. Chemical laboratory measures viscosity accurately with special apparatus, but they cannot be used in a real time process. This paper describes the development of a virtual sensor that estimates fuel oil viscosity in the combustion process of a power plant. A virtual sensor or soft sensor is a computer program that estimates the value of a certain variable based on related measurements and a model of the process where the variable participates. In this project, a probabilistic model is constructed using automatic learning algorithms with historical data and experts' advice. The learning and validation experiments are described and discussed. The virtual sensor is installed in the Tuxpan Power Plant in Veracruz, Mexico.     

Optical properties of dense zirconium and tantalum diborides for solar thermal absorbers

Ultra-high temperature ceramics (UHTCs) are interesting materials for a large variety of applications under extreme conditions. This paper reports on the production and extensive characterization of highly dense, pure zirconium and tantalum diborides, with particular interest to their potential utilization in the thermal solar energy field. Monolithic bulk samples are produced by Spark Plasma Sintering starting from elemental reactants or using metal diboride powders previously synthesized by Self-propagating High-temperature Synthesis (SHS). Microstructural and optical properties of products obtained by the two processing methods have been comparatively evaluated. We found that pure diborides show a good spectral selectivity, which is an appealing characteristic for solar absorber applications. No, or very small, differences in the optical properties have been evidenced when the two investigated processes adopted for the fabrication of dense TaB₂ and ZrB₂, respectively, are compared.     

阳江核电站液态流出物对阳江海域环境影响的计算模拟

本文针对阳江核电站50 km核应急计划区的阳江海域,采用切比雪夫谱方法计算了阳江海域的潮流速度和潮位值,进而采用粒子随机行走模型,模拟计算了阳江核电站正常工况下,液态流出物10 h连续排放后,阳江海域内核素氚的浓度分布。计算结果表明,核素迁移扩散24 d后到达海陵岛附近海域,此时有氚分布的区域常规相对浓度值低于0.005,活度浓度值低于0.70 Bq/L,该值与海陵岛海水氚的监测活度浓度(＜0.97 Bq/L)量级上相符。此结果表明,阳江核电站液态流出物中的核素氚对阳江海域环境无明显影响。