Particulate and semivolatile associated aliphatic hydrocarbon exhaust emission from heavy duty diesel vehicles

The exhaust emissions from two heavy duty diesel vehicles running on eight different fuel compositions were investigated regarding their content of high molecular weight (≥ C₁₂) aliphatic/ olefinic hydrocarbons. It was concluded that the emitted amount of semi‐volatile associated aliphatic hydrocarbons (range C₁₂‐C₂₂) depend on the fuel used in the engines and that these emissions mainly consisted of uncombusted fuel components. It was also found that uncombusted engine lubrication oil was the main constituent of the emitted particulate associated aliphatic hydrocarbons (C₁₇‐C₄₀). These constituted between 58% and 95% of the total emissions of the high molecular weight aliphatic compounds. Emission factors for the total of high molecular aliphatic hydrocarbons (C₁₂‐C₄₀) were demonstrated to be in the range of 15–100 mg/km. Some individual aliphatic hydrocarbons with cocarcinogenic effects were identified and quantified in both particulate and semi‐volatile phases of the exhaust. Multivariate data analysis was used to investigate the relationship between fuel parameters and emission of semi‐volatile aliphatic emission.     

Effects of a diesel oxidation catalyst on gaseous pollutants and fine particles from an engine operating on diesel and biodiesel

The effects of a diesel oxidation catalytic (DOC) converter on diesel engine emissions were investigated on a diesel bench at various loads for two steady-state speeds using diesel fuel and B20. The DOC was very effective in hydrocarbon (HC) and CO oxidation. Approximately 90%–95% reduction in CO and 36%–70% reduction in HC were realized using the DOC. Special attention was focused on the effects of the DOC on elemental carbon (EC) and organic carbon (OC) fractions in fine particles (PM_2.5) emitted from the diesel engine. The carbonaceous compositions of PM_2.5 were analyzed by the method of thermal/optical reflectance (TOR). The results showed that total carbon (TC), OC and EC emissions for PM_2.5 from diesel fuel were generally reduced by the DOC. For diesel fuel, TC emissions decreased 22%–32% after the DOC depending on operating modes. The decrease in TC was attributed to 35%–97% decrease in OC and 3%–65% decrease in EC emissions. At low load, a significant increase in the OC/EC ratio of PM_2.5 was observed after the DOC. The effect of the DOC on the carbonaceous compositions in PM_2.5 from B20 showed different trends compared to diesel fuel. At low load, a slight increase in EC emissions and a significant decrease in OC/EC ratio of PM_2.5 after DOC were observed for B20.     

Combined use of earthworm (Alma millsoni) and bacterium (Bacillus sp.) improved the bioremediation of spent engine oil contaminated soil

This study was carried out to assess the effectiveness of the combined use of earthworm (Alma millsoni) and bacterium (Bacillus sp.) in the bioremediation of spent engine oil (SEO) contaminated soils. A. millisoni were collected from the Botanical Garden of University of Ibadan, Nigeria. The stock culture of hydrocarbonoclastic Bacillus sp. was used for the bioremediation study. A set-up of eight pots containing 1000?g soil sample and 20?g of cow dung were mixed with 100, 75, 50 and 0?mL SEO respectively. Each of the set up was subjected to bioremediation agents; A. millisoni alone, Bacillus sp alone, A. millisoni and Bacillus sp, no treatment (control) in duplicate. Treatment of 100?ml SEO contaminated soil with combined A. millisoni and Bacillus sp resulted in significantly (P? bacterium > vermi-remediating agents. Earthworms exposed to 100?mLSEO-contaminated soil had higher CAT, SOD, and GPx activities compared to the control. Findings indicated that A. millisoni with Bacillus sp. can synergistically improve bioremediation of SEO contaminated soils.     

机械化学法修复柴油污染土壤的效率、产物及影响

针对常规污染土壤修复处理方法存在有毒降解产物、容易产生二次污染等问题,本研究采用行星球磨仪研究了机械化学法（MC）对柴油污染土壤的修复效能,利用GC/MS对柴油烃组分的降解产物进行分析,并采用SEM、XRD、BET、FTIR和TGA等方法对不同处理条件下的土壤样品进行表征.结果表明,MC处理在0.5~4.0 h内对土壤中总石油烃（TPH）的去除率可达95%以上.随着初始TPH浓度和球土质量比的升高,TPH去除率随之提高.采用MC处理后柴油组分降解难度顺序如下：烷烃<烯烃<环烷烃<芳香族化合物.在球磨处理4 h后,未检出有毒有害残留物质.球磨后土壤粒径变小,表面变粗糙,粘土矿物中的硅氧四面体暴露在土壤表面,矿物结构的结晶度逐渐降低,晶体结构逐渐破裂或变形,可在土壤表面形成富电子区域或促使土壤具有更高的反应活性,这是机械化学法高效降解柴油的主要机制.其次,土壤有机质的主要官能团受到破坏,纳米级孔隙容量降低,从而降低了土壤组分的吸附能力,增加了柴油的有效性,也有助于柴油的解吸和机械化学降解.此外,随着球磨时间的增加,土壤有机碳（SOC）含量先增加后下降,但均高于处理前.可见,MC处理可以快速彻底降解土壤中的柴油,且有利于增加土壤有机碳含量,对于石油烃污染土壤修复具有较好的应用潜力.     

卡源故障下悬挂链式辐照室火灾危险性研究

为了分析悬挂链式辐照室的火灾危险性,采用实验测定得出室内典型辐照物品的点着温度,通过设置3组火灾场景模拟得到卡源故障下各火灾场景辐照室内温度变化曲线。结果表明:各火灾场景卡源初期1 h,温度上升速度较快。随着时间的增长,室内温度不断上升,但上升速率逐渐放缓。在火灾场景A,B,C等3组条件下卡源故障分别发生9,4,2.4 d后,室内局部温度能达到210℃,室内辐照物品有可能被引燃。     

An Observation Method for Analyzing Operators’ Routine Activity in Computerized Control Rooms

An activity analysis method was developed for studying the structure and dynamics of control room operators’ activity during normal operation based on directly observable elements of the operators’ behavior. The method assesses current activity along three dimensions in each 5-min period of the shift. Intensity characterizes arousal level, direction shows whether the activity is directed predominantly at the process control task, at something else, or miscellaneous. Motivation reflects if the activity is driven by intrinsic or extrinsic motivation. A case study is presented, in which 3 morning, 3 afternoon, and 3 night shifts of a Nuclear Power Plant operator crew are involved. The obtained results gave a deeper understanding of the operators’ activity and also revealed an “arousal compensation” tendency.     

加拿大海盆与楚科奇海柱状沉积物中硫酸盐还原菌的分布状况

对取自北极楚科奇海及加拿大海盆的10个沉积物岩芯分别在4℃、25℃培养温度下进行硫酸盐还原菌(SRB)分析,结合首次北极科考海洋沉积物SRB的研究成果,探讨了研究区SRB的分布特点.研究结果表明,4℃与25℃温度培养的SRB含量均为0～2.4 ×106个·g-1(湿样);4℃时SRB的检出率与平均含量分别为45.5%和2.06×104个·g-1(湿样),25℃培养条件下分别为73.7%和4.70×104个·g-1(湿样);柱状沉积物中SRB的检出率、含量范围、平均含量都明显高于表层沉积物中SRB的相关指标;岩芯中SRB含量分布与采样点的纬度、深度有一定关系,但这种关系不如表层沉积物中SRB分布表现的那么明显;4℃培养时,各层位SRB含量的平均值范围为51～1.2×106个·g-1(湿样),25℃时为2.04×102～2.47×105个·g-1(湿样);在所研究的深度范围内,4℃时培养SRB的垂直变化较为明显,而25℃时SRB的垂直变化相对缓和;根据4℃、25℃2个不同培养温度时SRB的检出率、含量对比看,似乎25℃时更有利于某些SRB的繁衍.     

Combination of biodiesel-ethanol-diesel fuel blend and SCR catalyst assembly to reduce emissions from a heavy-duty diesel engine

In this study, the efforts to reduce NOx and particulate matter （PM） emissions from a diesel engine using both ethanol-selective catalytic reduction （SCR） of NOx over an Ag/Al2O3 catalyst and a biodiesel-ethanol-diesel fuel blend （BE-diesel） on an engine bench test are discussed. Compared with diesel fuel, use of BE-diesel increased PM emissions by 14% due to the increase in the soluble organic fraction （SOF） of PM, but it greatly reduced the Bosch smoke number by 60%-80% according to the results from 13-mode test of European Stationary Cycle （ESC） test. The SCR catalyst was effective in NOx reduction by ethanol, and the NOx conversion was approximately 73%. Total hydrocarbons （THC） and CO emissions increased significantly during the SCR of NOx process. Two diesel oxidation catalyst （DOC） assemblies were used after Ag/Al2O3 converter to remove CO and HC. Different oxidation catalyst showed opposite effect on PM emission. The PM composition analysis revealed that the net effect of oxidation catalyst on total PM was an integrative effect on SOF reduction and sulfate formation of PM. The engine bench test results indicated that the combination of BE-diesel and a SCR catalyst assembly could provide benefits for NOx and PM emissions control even without using diesel particle filters （DPFs）.     

城市污水厂初沉池的设置方式及运行效果

跟据初沉池在城市污水厂长期的实际运行数据,分析了初沉池去除污水中的悬浮物、有机物、降低能耗、降低水质波动对生化系统的冲击等方面所起的作用,设置初沉池还有利于提高生化系统污泥的活性成份（MLVSS／MLSS）、增强出水效果;同时探讨了初沉池在城市污水处理中的设置方式,通过设置超越管线,在冬、夏季水质波动较大,保持生化系统进水有机负荷的稳定,提出了优化初沉池的处理效果的运行方式。     

关于环境监测队伍组成结构的调查分析

对环境监测站人员年龄结构、岗位结构、学历结构、职称结构等的调查分析结果显示,为满足当前工作要求,监测站人员编制亟待增加、优胜劣汰的技术培训应成为制度。