把污染预防纳入化工过程和产品的研究开发与设计中

介绍了污染预防的概念以及在化工过程和产品的研究开发和设计中考虑污染预防的基本方法。并给出了一些简单实例予以说明。     

化学品安全技术说明书管理探究

我国化学品安全技术说明书制度在实施过程中还存在较多问题,为了更好地促进我国化学品管理,本文针对我国化学品安全技术说明书管理中的常见问题进行讨论与分析,提出管理建议,指出应提供安全技术说明书的化学品范围应分为合规管理与更高社会责任要求;安全技术说明书原则上应由生产企业编制,进口化学品在特殊情况下也可由进口企业组织编制;安全技术说明书在使用时应结合具体使用条件进行使用安全性评估等。     

水相中苯酚光催化降解的全额光子效率

为定量评价光催化反应器的性能,利用主辐射波长为207 nm的KrBr*准分子灯降解水相中的苯酚,测定了光解和光催化降解2种体系中苯酚和TOC去除率,并计算了苯酚降解的ξ_g(全额光子效率),探讨了其影响因素. 结果表明:①延长反应时间、加入适量催化剂、降低初始c(苯酚)能提高苯酚和TOC去除率. 采用动力学模型对苯酚的降解进行拟合,表明光解和光催化降解体系中苯酚的降解均符合准一级动力学模型. ②加入催化剂和提高初始c(苯酚)均可以获得较高的ξ_g,而光源的辐射功率与ξ_g没有线性相关性;在辐射功率为0.76 W、初始c(苯酚)为1.10 mmol/L、催化剂投加量(以ρ计)为0.8 g/L的条件下,ξ_g为5.56%. ③采用高效液相色谱对光催化降解体系中生成的中间产物的变化规律进行研究发现,4种中间产物表现为c(对苯二酚)＞c(邻苯二酚)＞c(对苯醌)＞c(间苯二酚);通过建立苯酚及中间产物的拟一级降解动力学模型,证实苯酚光催化降解历程为苯酚→芳香烃中间产物→最终产物.      

两种抗生素菌渣热解及燃烧特性对比研究

以华北某药厂链霉素、庆大霉素菌渣为原料,研究其资源化途径。通过工业和元素分析可知,两种菌渣C,O质量分数较高,H,N,S质量分数较低;链霉素菌渣中灰分和挥发分含量高于庆大霉素菌渣,而固定碳含量低于庆大霉素菌渣。通过热解实验可知,随热解温度升高,热解气产量增加,可凝结相和焦炭产量降低。热解气中H_2含量最高,庆大霉素菌渣热解时体积分数最高可达到57.6%,其次依次为CO_2,CO,CH_4等。两种热解气属于中热值气体,其低热值在10~15 MJ/m~3之间。链霉素和庆大霉素菌渣及其热解焦炭的热值分别为16.144,24.589,11.460,14.382 MJ/kg。     

基于层次分析法和布氏矩阵的产品绿色评价研究

针对当前多数产品评价中缺少对环保因素考虑的现状,构建由环境、资源、能源和经济指标组成的产品绿色评价指标体系,提出基于层次分析法和布氏矩阵的产品绿色评价方法.运用层次分析法确定绿色评价指标的权重,运用布氏矩阵对产品设计方案进行综合绿色评价,评选出环保性能最优的产品方案,进而节约资源,降低能耗,减少环境污染.并通过车载冰箱绿色评价实例验证了该方法的实用性和有效性.     

船用板式换热器可靠寿命预计方法研究

目的对于新型船用板式换热器进行可靠寿命预计,考虑到相似产品使用期间会获得定量的信息,提出一种利用相似产品信息进行产品可靠性预计的方法。方法相似产品的相似度由专家根据经验分析给出,其后根据继承因子直接对相似产品的可靠度进行折合。对板式换热器与相似产品的性能数据进行对比分析,利用模糊数学中贴近度的概念,计算得到两产品之间的折算系数。结果结合相似产品的实际使用数据,通过对流速、换热系数和其他相似因素的比较,得到产品对于相似产品的折算系数为0.286,从而进一步确定该板式换热器折算后的试验时间,利用无故障定时截尾寿命评估方法对该产品的可靠性进行粗略估计。结论该方法对利用相似产品进行寿命评估提供了一种新思路,从产品的性能特征出发,在一定程度上优化了专家评估相似度的主观因素。     

The capital gains from trade are not enough: evidence from the environmental accounts of Venezuela and Mexico

In principle, a country cannot endure negative genuine savings for long periods of time without experiencing declining consumption. Nevertheless, theoreticians envisage two alternatives to explain how an exporter of non-renewable natural resources could experience permanent negative genuine savings and still ensure sustainability. The first one alleges that the capital gains arising from the expected improvement in the terms of trade would suffice to compensate for the negative savings of the resource exporter. The second alternative points at technological change as a way to avoid economic collapse. This paper uses the data of Venezuela and Mexico to empirically test the first of these two hypotheses. The results presented here prove that the terms of trade do not suffice to compensate the depletion of oil reserves in these two open economies.     

Difficulties with the lognormal model in mean estimation and testing

A frequent assumption in environmental risk assessment is that the underlying distribution of an analyte concentration is lognormal. However, the distribution of a random variable whose log has a t-distribution has infinite mean. Because of the proximity of the standard normal and t-distribution, this suggests that a distribution such as the gamma or truncated normal, with smaller right tail probabilities, might make a better statistical model for mean estimation than the lognormal. In order to assess the effect of departures from lognormality on lognormal-based statistics, we simulated complete lognormal, truncated normal, and gamma data for various sample sizes and coefficients of variation. In these cases, departures from lognormality were not easily detected with the Shapiro-Wilk test. Various lognormal-based estimates and tests were compared with alternate methods based on the ordinary sample mean and standard error. The examples were also considered in the presence of random left censoring with the mean and standard error of the product limit estimate replacing the ordinary sample mean and standard error. The results suggest that in the estimation of or tests about a mean, if the assumption of lognormality is at all suspect, then lognormal-based approaches may not be as good as the alternative methods.     

哈密地区环境中氡及其子体浓度所致居民剂量评价

用双滤膜法和Ｔｈｏｍａｓ三段法测定了哈密地区环境空气中氡及其子体浓度．结果表明，室内氡及其子体浓度平均值分别为２８．ＯＢｑ·ｍ－３和７．５×１０－８Ｊ·ｍ－３，室外氡及其子体浓度平均值分别为１０．７Ｂｑ·ｍ－３和３．１×１０－３Ｊ·ｍ－３．氡及其子体所致居民人均有效剂量当量为１．０３ｍＳｖ·ａ－１，集体有效剂量当量为４．２×１０２ｍａｎ·Ｓｖ．     

Assessment of Antifouling Effectiveness of two Natural Product Antifoulants by Attachment Study with Freshwater Bacteria (7 pp)

- Goal, Scope, Background. The traditional solution for keeping unwanted organisms from attaching to submerged surfaces is to apply anti-fouling coatings. The most common antifoulant was tributyltin (TBT). TBT systems were highly effective but were also toxic to non-target organisms. The use of the TBT based coatings will be completely banned by January 1, 2008. Therefore, there is an urgent need to seek out suitable non-toxic alternatives. Methods The aim of this work was to evaluate the effectiveness of capsaicin and zosteric acid as natural product antifoulants (NPAs) in deterring bacterial attachment. Two fresh water bacteria systems Pseudomonas putida (Pp) and bacteria isolated from Lake Erie (LE) were used to assess the attachment when the NPAs dispersed in the water. Effectiveness was ascertained based on the decrease in microbial attachment, limited toxicity, and minimum alteration of the coatings properties. Results and Discussion A significant inhibition of bacteria attachment was achieved when aqueous capsaicin concentration was increased from 0 to 40 mg/L. For instance, after 14 days the LE system depicted 93.5% and 98.5% less biofilm coverage for 20 mg/L and 40 mg/L capsaicin, respectively when compared to systems without NPA. Biofilm coverage was reduced by 92.5% and 98.2%, respectively with 50 mg/L and 500 mg/L zosteric acid. Conclusions Both capsaicin and zosteric acid was effective at preventing bacteria attachment. As the NPA aqueous concentration increased, biofilm formation decreased. Evaluating changes in aqueous pH, conductivity, dissolved oxygen, aqueous microbial population and biofilm formation suggested that the primary antifoulant mechanism of these two NPAs was to block the bacteria's active sites versus posing a lethal level. Recommendation and Perspective From the attachment study, zosteric acid appeared to be more effective in preventing bacterial attachment when the NPAs were dispersed in the aqueous environment. For practical applications, the antifoulant needs to be incorporated into a coating and have a slow release rate. Thus the ability to successfully incorporate zosteric acid into a coating, without deterring bacterial attachment, needs to be investigated.