大型气相化学动力学软件包CHEMKIN及其在燃烧中的应用

燃烧化学反应动力学是计算燃烧学中的重要内容之一。本文介绍了处理气相化学动力学的大型软件包ＣＨＥＭＫＩＮ的结构和不同版本的特点,并描述了它在燃烧问题中的应用。最后通过一个算例对Ｈ２／Ｏ２／Ｎ２均相绝热等压燃烧体系进行了处理和计算,以具体说明该软件包的应用效果。     

考虑移动医院的因灾受损血液供应链网络重构

为快速恢复因灾受损的血液供应链的救援能力,针对血液这一重要医疗物资,研究考虑移动医院的应急供应链重构。设计包含移动医院和临时献血点选址、血液外调与自采和血液与伤员转运的混合整数规划模型,并以红细胞为例,将模型应用于我国龙门山地震带的灾害救治案例中。结果表明:重构的供应链能够综合运用移动医院等资源,快速恢复血液救援能力,最大程度缓解灾害影响。即便是在灾情最严重的情况下,缺血量可减少12.95%。管理者在进行人道主义应急救援决策时,应综合考虑移动医院等医疗资源的有效利用。     

Maintenance-related major accidents: Classification of causes and case study

The potential for major accidents is inherent in most industries that handle or store hazardous substances, for e.g. the hydrocarbon and chemical process industries. Several major accidents have been experienced over the past three decades. Flixborough Disaster (1974), Seveso Disaster (1976), Alexander Kielland Disaster (1980), Bhopal Gas Tragedy (1984), Sandoz Chemical Spill (1986), Piper Alpha Disaster (1988), Philips 66 Disaster (1989), Esso Longford Gas Explosion (1998), Texas City Refinery Explosion (2005), and most recently the Macondo Blowout (2010) are a few examples of accidents with devastating consequences.Causes are being exposed over time, but in recent years maintenance influence tends to be given less attention. However, given that some major accidents are maintenance-related, we intend to concentrate on classifying them to give a better insight into the underlying and contributing causes.High degree of technological and organizational complexity are attributes of these industries, and in order to control the risk, it is common to deploy multiple and independent safety barriers whose integrity cannot be maintained without adequate level of maintenance. However, maintenance may have a negative effect on barrier performance if the execution is incorrect, insufficient, delayed, or excessive. Maintenance can also be the triggering event.The objectives of this article are: (1) To investigate how maintenance impacts the occurrence of major accidents, and (2) To develop classification schemes for causes of maintenance-related major accidents.The paper builds primarily on model-based and empirical approaches, the latter being applied to reports on accident investigation and analysis. Based on this, the Work and Accident Process (WAP) classification scheme was proposed in the paper.     

水热条件下绿矾稳定垃圾焚烧飞灰的研究

研究了饱和温度为200 ℃的水热条件下绿矾对垃圾焚烧飞灰中重金属的稳定效果,并与常温常压下的稳定效果进行了对比.研究结果表明,高温水热条件有利于Pb特别是Cr(Ⅵ)的稳定,对Cd的稳定无明显影响,同时绿矾的用量大为降低,降低了药剂的成本.     

Removal of AOX, total nitrogen and chlorinated lignin from bleached Kraft mill effluents by UV oxidation in the presence of hydrogen peroxide utilizing TiO2 as photocatalyst

Background, aim, and scope  The pulp and paper industry is the sixth largest polluter discharging a variety of gaseous, liquid, and solid wastes into the environment. Effluents from bleached Kraft mill effluents (BKME) are polluting waters to a great extent These effluents cause considerable damage to the receiving waters if discharged untreated since they have high levels of biological oxygen demand (BOD), chemical oxygen demand (COD), chlorinated compounds (measured as AOX), suspended solids (mainly fibers), fatty acids, tannins, resin acids, lignin and its derivatives, sulfur and sulfur compounds, etc. This study aimed to remove adsorbed organic halogen (AOX), total nitrogen, and lignin-degrading products in the wastewater (4,500 m³/h) from the paper mill in the pulp and paper industry, which is discharged to sea from a plant located in western Turkey. Materials and methods  The photocatalytic degradation of AOX, total nitrogen, and chlorinated lignin in BKME have been investigated in different parameters, such as time, H₂O₂ and TiO₂ concentration. In addition, for investigating the effect of chlorine on the removal of lignin, pure lignin solution was prepared in equal amounts to chlorinated lignin degradation products found in BKME. The same experiments were conducted for this solution. Experiments were carried out in photocatalytic reactor made of Pyrex glass. The mercury lamp was used as a radiation source. All irradiation was carried out under constant stirring. The existence of dissolved O₂ is an important factor which increases the photocatalytic degradation. Hence, we used an air pump for the aeration of the wastewater solutions. The temperature of the wastewater was controlled and adjusted to 25°C by thermostat pump in conjunction with a cooler. At the end of all experiments, AOX, total nitrogen and lignin concentrations were analyzed according to standard methods. All experiments were performed in duplicate and average values were used. Results and discussion  When the effect of H₂O₂ and time were investigated, it was observed that the AOX concentration increased from 3.0 to 11.0 mg/L by only UV. However, when H₂O₂ was added, AOX concentration decreased from approximately 3.0 to 0.0 mg/L. The optimal conditions for the removal of AOX appear to be an initial H₂O₂ concentration of 20.0 mL/L and reaction time of 50 min. In addition, at the same experiment conditions, it was seen that the total nitrogen concentration decreased from 23.0 to 15.0 mg/L by only UV and by increasing H₂O₂ concentration, the concentration of 20.0 mL/L H₂O₂ appears to be optimal (9.0 mg/L). The AOX, total nitrogen and lignin degradation products and pure lignin go through a minimum when the concentration of H₂O₂ and TiO₂ increases at constant pH and UV intensity. The kinetics for the degradation of AOX, total nitrogen and lignin degradation products followed a pseudo-first order law with respect to the products, and the degradation rates (min⁻¹) for the UV/TiO₂/H₂O₂ system were higher than that of the corresponding values for the UV/H₂O₂ system. Conclusions  The AOX, total nitrogen and lignin concentration go through a minimum when the concentration of H₂O₂ and TiO₂ increases at constant pH and UV intensity. It was found that the UV/TiO₂/H₂O₂ system has proved capable of the degradation of total nitrogen as well as chlorinated and degraded lignin in BKME. Recommendations and perspectives  The photocatalytic process can be considered a suitable alternative for the remove of some compounds from the BKME. Nevertheless, further studies should be carried out to confirm the practical feasibility of BKME. Another result obtained from the study is that pre-purification carried out with UV/TiO₂/H₂O₂ photocatalytic process may constitute an important step for further purification processes such as adsorption, membrane processes, etc.     

Fecal coliforms, caffeine and carbamazepine in stormwater collection systems in a large urban area

Water samples from streams, brooks and storm sewer outfall pipes that collect storm waters across the Island of Montréal were analyzed for caffeine, carbamazepine and fecal coliforms. All samples contained various concentrations of these tracers, indicating a widespread sanitary contamination in urban environments. Fecal coliforms and caffeine levels ranged over several orders of magnitude with a modest correlation between caffeine and fecal coliforms (R² value of 0.558). An arbitrary threshold of 400 ng caffeine L⁻¹ allows us to identify samples with an elevated fecal contamination, as defined by more than 200 colony-forming units per 100 mL (cfu 100 mL⁻¹) of fecal coliforms. Low caffeine levels were sporadically related to high fecal coliform counts. Lower levels of caffeine and fecal coliforms were observed in the brooks while the larger streams and storm water discharge points contained over ten times more. The carbamazepine data showed little or no apparent correlation to caffeine. These data suggest that this storm water collection system, located in a highly urbanized urban environment, is widely contaminated by domestic sewers as indicated by the ubiquitous presence of fecal contaminants as well as caffeine and carbamazepine. Caffeine concentrations were relatively well correlated to fecal coliforms, and could potentially be used as a chemical indicator of the level of contamination by sanitary sources. The carbamazepine data was not significantly correlated to fecal coliforms and of little use in this dataset.     

淮北市叶菜类蔬菜中硝酸盐含量的调查

通过对淮北市近郊几个大的蔬菜生产基地叶菜类蔬菜中硝酸盐含量的分析,发现淮北市叶菜类蔬菜中硝酸盐含量普遍很高,且有超标状况存在。究其因,主要是化肥的过量使用,使蔬菜中的硝态氮不能及时还原,累积于体内。     

Intergovernmental relationships after disaster: state and local government learning during flood recovery in Colorado

ABSTRACT

When communities experience disaster, emergency response and recovery are led internally, based on local-level policy decisions and priorities. Decisions about how or whether to rebuild are made by local governments. Higher governmental authorities such as states and provinces may institute their own disaster recovery processes and policies in addition to or in competition with local governments. Greater intergovernmental engagement could increase resources and knowledge, which would yield higher levels of learning and result in superior disaster recovery policy outcomes. The role of higher authorities, then, can have important implications for policy processes and outcomes. The learning literature includes a dearth of studies that analyze the relationships between state and local governments during disaster recovery. We move the learning literature forward by analyzing intergovernmental relationships during disaster recovery. We find that learning within local governments is associated with higher levels of resource flows from state agencies as well as more collaborative intergovernmental relationships. We also find that state governments can improve processes for disaster recovery assistance and bring together disaster-affected local governments to promote learning during the recovery process. While this study focused on relationships constrained by U.S. federal dynamics, the lessons are useful to other multilevel governance systems.     

白龙港污水处理厂处理工艺比较分析

在对上海污水治理二期工程白龙港排放口水质进行监测分机和模拟处理试验的基础上，根据不同的排放标准，对白龙港污水处理厂处理工艺分别提出了不同方案并作了技术、经济比较分机。提出如果执行《污水综台排放标准》，可以采用化学法 悬浮粒子接触氧化法处理工艺；如果执行《城镇污水处理厂污染物排放标准》，可以采用A／0生物法处理工艺。     

炼油化工废水处理技术进展

评述了国内外在炼油化工废水处理的活性污泥技术改进、微生物处理与物化处理组合技术、难降解废水无害化处理技术以及污水回用技术方面的新进展。