混凝土结构可靠度的Monte Carlo模拟

简介了靠度与安全系数的区别；以混凝土结构为例，介绍了用Monte Carlo模拟来计算结构可靠度的方法。     

Indirect effect of nutrient accumulation intensified toxicity risk of metals in sediments from urban river network

The levels of metals in sediments of urban river ecosystems are crucial for aquatic environmental health and pollution assessment. Yet little is known about the interaction of nutrients with metals for environmental risks under contamination accumulation. Here, we combined hierarchical cluster, correlation, and principal component analysis with structural equation model (SEM) to investigate the pollution level, source, toxicity risk, and interaction associated with metals and nutrients in the sediments of a river network in a city area of East China. The results showed that the pollution associated with metals in sediments was rated as moderate degree of contamination load and medium-high toxicity risk in the middle and downstream of urban rivers based on contamination factor, pollution load index, and environmental toxicity quotient. The concentration of mercury (Hg) and zinc (Zn) showed a significant correlation with toxic risks, which had more contribution to toxicity than other metals in the study area. Organic nitrogen and organic pollution index showed heavily polluted sediments in south of the study area. Though correlation analysis indicated that nutrients and metals had different input zones from anthropogenic sources in the urban river network, SEM suggested that nutrient accumulation indirectly intensified toxicity risk of metals by 13.6% in sediments. Therefore, we suggested the combined consideration of metal toxicity risk with nutrient accumulation, which may provide a comprehensive understanding to identify sediment pollution.

Toxicity rate of metals in sediments from urban river network indirectly intensified by nutrients accumulation

     

非均相催化湿式氧化法活性炭再生

使用浸渍法制备的CuO Al2 O3催化剂对吸附苯酚饱和的活性炭进行非均相催化湿式氧化再生研究 ,考察了反应温度、反应时间、催化剂投加量、反应氧分压、投炭量、蒸馏水量对非均相催化湿式氧化再生活性炭的影响结果 ,同时在该实验中得到非均相CuO Al2 O3催化湿式氧化再生活性炭的最佳条件。对催化剂进行了X衍射分析 ,并通过对催化剂的稳定性进行实验 ,得出该催化剂在进行催化湿式氧化再生活性炭的过程中具有较好的稳定性     

城市固体废物好氧生物反应器填埋方式的实验研究

MSW（城市固体废物）生物反应器型填埋是一种较新颖的方法.在系统分析现有填埋方法优缺点的基础上,对其加以改进,将强制通风好氧和渗滤液循环2种方式有机地结合在一起,构建了MSW好氧生物反应器.考察了NH3、CH4、CO2、pH和温度等因素,并监测分析了渗滤液中的COD、BOD5、Zn^2＋、NH4^＋和NO3^-等指标,旨在研究其中垃圾的降解及渗滤液中COD、BOD5、Zn^2＋、NH4^＋和NO3^-的去除情况,探讨该生物反应器对垃圾和渗滤液相关参数的作用机理.结果表明,该反应器对渗滤液中COD、BOD5、NO3^-的去除率分别达到96.34%、94.58%和99.9%,对其中的Zn^2＋也有较好的脱除效果.     

Ozonation of Cationic Red X-GRL in aqueous solution: degradation and mechanism

Ozonation of the azo dye Cationic Red X-GRL was investigated in a bubble column reactor at varying operating parameters such as oxygen flow rate, temperature, initial Cationic Red X-GRL concentration, and pH. The conversion of dye increased with the increasing of pH and oxygen flow rate. As the reaction rate constant and the volumetric mass transfer coefficient increase while the ozone equilibrium concentration decreases with the temperature, there is a minimum conversion of dye at 25 degrees C. The increasing of initial dye concentration leads to a decreasing conversion of dye while the ozonation rate increases. The formation of intermediates and the variation of pH, TOC, and nitrate ion during ozonation were investigated by the use of some analytical instruments such as GC/MS, GC, and IC. The intermediates of weak organic acids lower the pH value of the solution. The probable degradation mechanism of the Cationic Red X-GRL in aqueous solution was deliberated with the aid of Molecular Orbital calculations. The N(12)-C(13) site in Cationic Red X-GRL, instead of the N(6)-N(7) site, is found to be the principal site for ozone cycloaddition in the degradation processes. During the degradation process, among the six nitrogen atoms of Cationic Red X-GRL, one is transferred into a nitrate ion, one is converted into an amine compound, and the remaining four are transformed into two molecules of nitrogen.     

Selective extraction of trace mercury and cadmium from drinking water sources.

In this paper, a new alternative method, i.e., selective extraction by weakly basic anion exchange resin, has been developed for the removal of trace cadmium and mercury ions from drinking water sources. The mechanism of heavy metal removal is based on selective extraction as the results of LEWIS-base-acid interactions. Transfer of trace mercury species from liquid to resin phase coincides well with the performance of film diffusion. The results demonstrated that the presence of chlorine has a negligible influence on the removal of mercury. However, humic acids can strongly bind mercury by the formation of complex compounds and therefore become the obstacle in the diffusion progress. At neutral or base pH, the resin material exhibits the favorable uptake of heavy metals. In filter experiments, the studied resin material offers favorable properties in the selective extraction of trace mercury and cadmium.     

A real-time optimization method for economic and effective operation of electrostatic precipitators

ABSTRACT

Electrostatic precipitators (ESP) have been considered as the main particulate matter (PM) removal facility in the energy industry. This paper presents a real-time optimization method for a one-chamber industrial ESP in an ultra-low emission power plant with an intelligent optimization system (IOS). The IOS seeks to optimize the energy consumption of ESP subject to the outlet concentration requirement in real-time. A coordination control logic is designed to regulate the optimized operation set points with varying operation conditions. The operation optimized by the IOS is compared with the operations under PID (proportion-integral-derivative) and manual control. The results show that the IOS improves the emission compliance rate from 95% of manual control to 100% and the medium concentration is tuned to be 46.6% closer to the emission target. Furthermore, a good balance between emission and energy consumption is achieved, with 35.50% energy conservation for the same emission upper limit of 30 mg/m³. These results prove that the IOS significantly contributes to the efficient operation and economic PM removal by ESP for the energy industry.     

随身自动空气净化处理器的研究

随身自动空气净化器,采用了活性炭、光催化技术相结合的空气过滤装置.空气污染传感器与单片机组成空气质量监测电路,当空气污染超标时,产生语音提示,液晶屏显示空气质量的等级,自动(或手动)控制引风机工作,供给个人清新无污染的空气.     

Photocatalytic reactions of pyrene at TiO2/water interfaces

The photocatalytic oxidation of pyrene preadsorbed on TiO2 is examined in aqueous suspension under UV irradiation. Chemical oxygen demand measurements, UV-VIS spectrophotometer, infrared spectrometer and GC-MS analytical techniques were used to monitor the formed intermediates. During the oxidation processes, the ring-open reaction, hydroxylation and ketolysis occurred to produce some intermediate products (4-oxapyrene-5-one, 1,6- or 1,8-pyrenediones, 4,5-phenanthrenedialdehyde, cyclopenta[def]phenanthrene). Some factors affecting the photodegradation rate were also studied. The results were different from other studies: The pH of the dispersion, ratio of Py/TiO2:water had little effect on the photooxidation rate of pyrene catalyzed by TiO2, while the surface coverage, addition of Fe3+ affected it greatly.     

Removal of alachlor from water by catalyzed ozonation in the presence of Fe2+, Mn2+, and humic substances

The effects of Fe(II), Mn(III) and humic substances on the catalyzed ozonation of alachlor, an endocrine disruptor were investigated. Results revealed that small amounts of Fe(II), Mn(II), and humic substances could enhance the ozonation of alachlor, but larger amounts of them would retard the oxidation. These results were successfully identified by an electron paramagnetic resonance (EPR) spectroscopy spin-trapping method that could quantify hydroxyl radicals. The production of hydroxyl radicals was obviously increased with the increasing of Fe(II) concentration, which contributed to enhance ozonation at low concentrations. But the excess Fe(II) consumed some of the radicals when it was added at a higher concentration (1.5 mg/L). However, no obvious radicals were observed when a different amount of Mn(II) was used, and the catalytic ozonation of alachlor by Mn(II) mainly followed the mechanism of "active sites created on the surface of MnO2." The radical pathway was followed when alachlor was ozonated with different concentrations of humic substances because of its radical initiating, promoting, and inhibiting effects.