Development of a prefabricated treatment plant for diluted pig wastewater

In order to develop a prefabricated treatment and reuse plant for diluted pig wastewater, an entrapped-mixed-microbial-cell (EMMC) process was evaluated for its process performance and economic analysis. At the hydraulic retention time (HRT) of 30 hrs (loading rate of 1.0 g TCOD/L/d) and intermittent aeration of 1 hr of aeration and 1 hr of non-aeration, it was found that, by using the pretreatment of the ammonium crystallization, both the medium and large carriers were able to reduce TCOD, SCOD, and T-N by 83.51, 84.11, and 95.10%, respectively. The EMMC unit and lime post-treatment followed by ammonium crystallization can reduce BOD5, TCOD, SCOD, TSS, T-N, and T-P, respectively by 99.22, 93.85, 92.67, 97.73, 96.43, and 97.27%. The treated wastewater, after disinfection, is able to meet the requirements of the standards issued by the USEPA for reuse of food crops. The economic analysis indicates that based on the process performance of the EMMC unit, a prefabricated wastewater treatment plant for 2000 pigs has comparable net present worth (NPW) comparing intermittent aerated biological systems and less operation and maintenance and land requirement than conventional biological processes for removal carbon and nitrogen. A farm operation of more than 2000 pigs meets the unit cost of US$4.91/pig/yr. This will minimize the problems pertaining to technical factors or considerations that heavily influence planning, construction and operation of a pig wastewater treatment system.     

《安全科学技术基础》课程教材编写初探

论述了《安全科学技术基础》课程 ,在安全工程专业知识结构中 ,处于“学科平台”中的“平台”地位 ;笔者指出 ,编写一本适合安全工程本科专业使用的课程教材既有必要性 ,也有可行性 ;提出了“以安全为主线”、从“安全的角度和着眼点”作为该课程编写的原则 ;初步探讨了该课程应涵盖的内容 ,并从 12个方面就“安全科学哲学”、“安全系统科学”和“安全科学学”的内容进行了简要概述。     

Software,shareware and freeware: multiplex commitment to an electronic social exchange system

We observe the behavior of 37 authors of shared (i.e., non‐commercial) software for the Apple Newton in terms of multiplex commitment (committed to multiple related targets) and the helping behaviors directed at these multiple related targets. The behavior of these shared software authors show a pattern of commitment to related targets consistent with our expectations of multiplex commitment and relationships to two helping behaviors (the number of shared software programs produced, and the degree of sacrifice expected with that shared software). The related targets of commitment were the users of the software, other shared software authors, and the newsgroup that served as the electronic social exchange system, but not the FTP site that enabled the exchange or the Listserv that served as an additional electronic social exchange system. Copyright © 2002 John Wiley & Sons, Ltd.     

用安全学科理论指导安全工程本科专业的课程体系建设

以安全科学技术体系的观点 ,提出了与以往有所不同的安全专业科学技术体系的构架 ,论述了安全工程专业完整的知识结构 ,探讨了符合安全专业科学技术体系理论的安全工程本科专业的课程设置 ,以期对我国安全工程专业的高等教育教学改革起到抛砖引玉的作用     

关于整合管理体系的若干问题的思考

针对国内外出现的整合质量管理体系 (QMS)、环境管理体系 (EMS)与职业安全卫生体系(OSHMS)的现状 ,笔者分析了当前整合的困难与存在的问题 ,进而提出了相应的改进措施。     

油罐扬沸火灾及其安全防治对策

本文应用模拟实验研究方法,考察了扬沸过程的基本物理性状及其特点,在研究了扬沸形成规律的基础上,提出了两个新的安全防治对策:利用扬沸前兆噪声诊断、预报扬沸发生及应用循环冷却原理阻止扬沸形成。     

固相萃取-气相色谱法检测水中的邻苯二甲酸酯

利用固相萃取技术富集了水中4种邻苯二甲酸酯类（PAEs）化合物：邻苯二甲酸二甲酯（DMP）、邻苯二甲酸二乙酯（DEP）、邻苯二甲酸二丁酯（DBP）、邻苯二甲酸二（2-乙基己基）酯（DEHP）。借助均匀设计法及计算机回归建模优化技术对4种PAEs的固相萃取条件进行了设计与优化，得到的最佳固相萃取条件：洗脱剂配比（正己烷与丙酮的体积比）30：1，洗脱体积2mL，洗脱速率4mL／min，上样速率8mL／min。富集后的试样用带电子捕获器的毛细管气相色谱仪检测，方法的线性范围为1～1000μg／L（DMP，DEP），0．2—100μg／L（DBP，DEHP），线性回归方程的相关系数为0．9970～1．0000，检出限为0．02-0．4μg／L，4种PAEs的回收率为69％～117％，相对标准偏差为2．5％～9．5％。[关键词]     

Population growth of the blackmargined aphid on pecan in the field

Caged populations of Monellia caryella (Fitch) were observed to condition pecan leaves throughout the season resulting in the leaves being unsuitable for subsequent colonization. Aphid populations were greatest (peak of 70 aphids/leaf) and occurred for a longer period (25 days) compared to late season activity (peak of 37 aphids/leaf, lasting 11 days) before conditioning occurred in closed cages. Intrinsic rates of increase per day or per degree-day declined during the season. Population growth was best described using an exponential increase equation compared to a logistic equation. These results indicated that as pecan leaves aged they were a poorer substrate for M. caryella and more easily made unsuitable for subsequent colonization.     

Compartmental human respiratory tract modeling of airborne dust exposure from feeding in swine buildings

A simple size-dependent compartmental model was developed to describe airborne dust exposure dynamics for the human respiratory tract (HRT) in mechanically ventilated swine buildings. Transport mechanisms of airborne dust for HRT include respiration, gravitational settling, turbulent diffusive deposition, inertial impaction, interception deposition loss, and dust clearance. The dominant deposition mechanism in the lung regions was found to be the inertial impaction rate, in which the order of magnitude ranged from 10(-3) to 10(-1) sec(-1). Results demonstrate that the extrathoracic region has a higher airborne dust mass lung/indoor ratios (0.71-0.87) than do the bronchial regions (0.41-0.74), the bronchiolar region (0.12-0.61), and the alveolar-interstitial region (0.01-0.49). The predictions from the HRT model agreed favorably with the experimental deposition profiles in the nasal passage, pharynx, bronchial, bronchiolar, and alveolar-interstitial regions, whereas the rms errors of the total deposition fraction between predicted values and ICRP66 and Non-ICRP66 were 0.15 and 0.07, respectively. Simulation results show that breathing via the nose has both a higher deposition fraction and a higher exposure dose in the size ranges 0.01-10 microm than does breathing orally.     

基于风险的大型储罐检验周期制定

介绍了目前在用的几种大型储罐检验周期的制定方法,并对其特点进行了分析对比,重点介绍了运用基于风险的检验制定检验周期的方法。