低浓度甲苯在固定床活性炭上的吸附及其数值模拟

对气体中低浓度甲苯在固定床活性炭上的吸附作了系统研究,测定了甲苯－空气活性炭系统的吸附等温线以Φ２６０×１４０ｍｍ活性炭固定床的穿透曲线,并在低浓度范围建立了固定床活性炭吸附甲苯数学模型。计算结果与实验结合吻合良好,所建模型可用于预测其它条件下的穿透曲线。     

可再生能源资源评价体系与方法

本文根据可再生能源资源的特性以及与技术、市场之间的内在联系,构建了可再生能源的资源评价体系,分析了资源量、生产率、生产经济性及不确定性分析等各环节中的具体评价方法和指标框架,并提出了最小和最大经济获利开发量以度量资源生产的经济性潜力     

A respirometric method to measure mineralization of polymeric materials in a matured compost environment

A respirometric method was developed to measure the mineralization of polymeric materials in a matured compost environment. For the purpose of evaluating the method, results obtained for the mineralization of glucose and cellulose are presented. The matured compost, in addition to supplied nutrients, micronutrients, and an inoculum, serves as the matrix which supports the microbial activity. Recovery of the substrate carbon in the form of carbon dioxide from the glucose and cellulose added to test vessels was 68 and 70%, respectively. A statistical evaluation of the results obtained on substrate mineralization was carried out and showed acceptable reproducibility between replicate test vessels and test runs. The testing protocol developed has the following important characteristics: (1) the test reactors are maintained at 53 °C at a high solids loading (60% moisture), which has certain characteristics that are similar to a thermophilic compost environment; (2) the test matrix providing microbial activity is derived from readily available organic materials to facilitate reproducibility of the method in different laboratories; (3) the equipment required to perform this test is relatively inexpensive; and (4) the information obtained on polymer mineralization is vital to the study and development of biodegradable polymeric materials.Guest Editor: Dr. Graham Swift, Rohm & Haas.     

1991／1992年世界气象灾害评述

1991/1992年是厄尔尼诺年,也是全球自然灾害频发、重灾事件突出的异常年份。本文对发生在1991/1992年厄尔尼诺事件期间的全球主要气象灾害进行简介和评述。     

EFFECT OF WATERSHED SUBDIVISION ON SWAT FLOW,SEDIMENT, AND NUTRIENT PREDICTIONS1

ABSTRACT: The size, scale, and number of subwatersheds can affect a watershed modeling process and subsequent results. The objective of this study was to determine the appropriate level of subwatershed division for simulating flow, sediment, and nutrients over 30 years for four Iowa watersheds ranging in size from 2,000 to 18,000 km² with the Soil and Water Assessment Tool (SWAT) model. The results of the analysis indicated that variation in the total number of subwatersheds had very little effect on streamflow. However, the opposite result was found for sediment, nitrate, and inorganic P; the optimal threshold subwatershed sizes, relative to the total drainage area for each watershed, required to adequately predict these three indicators were found to be around 3, 2, and 5 percent, respectively. Decreasing the size of the subwatersheds below these threshold levels does not significantly affect the predicted levels of these environmental indicators. These threshold subwatershed sizes can be used to optimize input data preparation requirements for SWAT analyses of other watersheds, especially those within a similar size range. The fact that different thresholds emerged for the different indicators also indicates the need for SWAT users to assess which indicators should have the highest priority in their analyses.     

Impact of sample preparation on mineralogical analysis of zero-valent iron reactive barrier materials

Permeable reactive barriers (PRBs) of zero-valent iron (Fe(0)) are increasingly being used to remediate contaminated ground water. Corrosion of Fe(0) filings and the formation of precipitates can occur when the PRB material comes in contact with ground water and may reduce the lifespan and effectiveness of the barrier. At present, there are no routine procedures for preparing and analyzing the mineral precipitates from Fe(0) PRB material. These procedures are needed because mineralogical composition of corrosion products used to interpret the barrier processes can change with iron oxidation and sample preparation. The objectives of this study were (i) to investigate a method of preparing Fe(0) reactive barrier material for mineralogical analysis by X-ray diffraction (XRD), and (ii) to identify Fe mineral phases and rates of transformations induced by different mineralogical preparation techniques. Materials from an in situ Fe(0) PRB were collected by undisturbed coring and processed for XRD analysis after different times since sampling for three size fractions and by various drying treatments. We found that whole-sample preparation for analysis was necessary because mineral precipitates occurred within the PRB material in different size fractions of the samples. Green rusts quickly disappeared from acetone-dried samples and were not present in air-dried and oven-dried samples. Maghemite/magnetite content increased over time and in oven-dried samples, especially after heating to 105 degrees C. We conclude that care must be taken during sample preparation of Fe(0) PRB material, especially for detection of green rusts, to ensure accurate identification of minerals present within the barrier system.     

纳氏试剂光度法测定废水中氨氮的问题讨论

应用纳氏试剂比色法测定废水中的氨氮时,水样显色后稳定时间短,影响测定结果的准确性,针对这一问题进行了实验研究。实验中对主要影响因素Ｉ－和ＯＨ－的浓度变化进行了条件实验,结果表明选用所配的Ⅲ型纳氏试剂（ＫＩ含量为７．５ｇ）,可获得稳定的有色胶体,也可采用Ⅰ型纳氏试剂（ＫＩ含量为７．０ｇ）、在中和硼酸后再多加２ｍＬＮａＯＨ（１ｍｏｌ／Ｌ）,也可获得稳定的有色胶体。     

铁路安全管理与安全工程、安全文化

论述了铁路安全工作中的工程问题和文化问题，提出铁路安全基础建设工程应是加强铁路安全综合性研究与综合管理，建设铁路安全文化。     

A Multi-Channel Continuous Water Toxicity Monitoring System: Its Evaluation and Application to Water Discharged from a Power Plant

A multi-channel continuous water toxicity monitoring system was, after confirming the systems' performance, implemented to samples of water discharged from power plants to detect and classify their toxicity using several recombinant bioluminescent bacteria. Each channel of the system is composed of a series of two mini-bioreactors to enable a continuous operation, i.e., without system interruption due to highly toxic samples. A different recombinant bacterial strain was present in each channel: DPD2540 (fabA::lux CDABE), DPD2794 (recA::luxCDABE), and TV1061 (grpE::luxCDABE), which are induced by cell membrane-, DNA-, and protein-damaging agents, respectively. GC2 (lac::luxCDABE) is a constitutive strain, whose bioluminescence is reduced by an increase in cellular toxicity. Phenol and mitomycin C (MMC) were used for evaluating the system's performance to detect toxic chemicals. These samples were injected into the second mini-bioreactor according to a step or bell-curve manner. The field samples used in this study were obtained from the water discharged from two different power plants in Korea – from a nuclear power plant and a thermo-electronic power plant, and were injected into the second mini-bioreactor to initiate the toxicity test. Each channel showed specific bioluminescent (BL) response profiles due to the toxic compounds present in the water samples. Comparing the BL signals between the standard toxic chemical samples and discharged water samples, the equivalent toxicity of the field water could be estimated. Finally, it was proved that this novel continuous toxicity monitoring system can be used as an alternative tool for the quick monitoring and control of water quality, as well as aid in the setting up of a new monitoring strategy to protect the source of tap water and in the prevention of polluted water discharge.