Release characteristics of mercury in chemical looping combustion of bituminous coal

This study evaluated the release characteristics of mercury from bituminous coal in chemical looping combustion (CLC) using Australian iron ore as the oxygen carrier in a fixed bed reactor. The effects of several parameters, such as temperature in the fuel reactor (FR) and air reactor (AR), gasification medium in the FR, and reaction atmosphere in the AR, on mercury release characteristics, were investigated. The mercury speciation and release amount in the FR and AR under different conditions were further explored. The results indicate that most of the mercury in coal was released in the FR, while the rest of it was released in the AR. Hg⁰ was found to be the major species in the released mercury. The results also indicate that a higher temperature in the FR led to an increase in the total mercury release amount and a decrease in Hg⁰ proportion. However, a higher temperature in the AR resulted in a decrease in the total mercury release amount and Hg⁰ proportion. The increase in the H₂O/CO₂ ratio of gasification mediums in the FR was beneficial for the increase in the total mercury release amount and Hg⁰ proportion. A higher O₂ concentration in reaction atmosphere in AR had a negligible effect on the total mercury release amount, but a positive effect on Hg⁰ oxidization.     

Distribution of polychlorinated naphthalenes (PCNs) in the whole blood of typical meat animals

The concentrations and distribution of polychlorinated naphthalenes(PCNs) in the whole blood of eight typical terrestrial meat animals(chicken, duck, rabbit, pig, cattle, sheep,horse and donkey) consumed daily in our life were investigated. The total concentrations(on a liquid volume basis) of PCNs were in a range from 305 to 987 pg/L. Donkey blood contained the highest PCN concentrations. Mono-CNs were the dominant homolog group,accounting for 38%–71% PCNs. Apart from the mono-CNs and tri-CNs homolog groups, two hepta-CNs(mean: 9.5%) contributed most, followed by tetra-CNs(mean: 6.5%). The congeners CN1, 5/7, 24/14, 27/30, 52/60, 66/67, and 73 were the most abundant congeners or congener groups. The highest toxicity equivalencies(TEQs) were observed in cattle blood(117.4 fg TEQ/L) then chicken blood(117.1 fg TEQ/L). CN73 contributed 65% to total TEQs,followed by CN70(20%) and CN66/67(14%). The dietary intakes of PCNs were also estimated.Chicken meat, which forms the second largest component of meat product consumption in China, contributed most to the total TEQs(61%), followed by beef(27%) and pork(5.9%). The consumption of chicken might pose the highest risk from exposure to PCNs than other types of meat to populations who prefer to eat chicken meat.     

Sediment-water distribution of perfluorooctane sulfonate (PFOS) in Yangtze River Estuary

Analysis of Perfluorooctane sulfonate (PFOS) distribution in water and sediment in Yangtze River Estuary showed that the estuary was a sink for PFOS. Salinity was an important parameter in controlling the sediment-water interactions and the fate or transport of PFOS in the aquatic environment. As the salinity (S‰) increased from 0.18 to 3.31, the distribution coefficient (K_d) between sediment and water linearly increased from 0.76 to 4.70 L g⁻¹. The study suggests that PFOS may be carried with the river water and transported for long distances before it reaches to the sea and largely scavenged to the sediment in the estuaries due to the dramatic change in salinity.     

The effect of fluorescent tracers on droplet spectrum,viscosity, and density of pesticide formulations

The most important factor affecting efficacy and drift of pesticide applications is the droplet spectrum. To measure pesticide drift, researchers utilize fluorescent tracers to rapidly quantify spray deposition. Although fluorescent tracers have been used for more than 50 years, no experiments have been performed on the effect they have on the properties of pesticide formulations (density and viscosity) or droplet spectrum, which affect the drift of pesticides. Therefore, we examined the effect of an oil- and water-based tracer on the volume median diameter (VMD), viscosity, and density of oil- and water-based pesticide formulations. In addition, we experimentally fit and demonstrate the utility of using distributions to characterize pesticide droplet spectra. The addition of tracers to both water- and oil-based formulations did not significantly alter the VMD, viscosity, and density. Lognormal distributions provided the best fit for the water- and oil-based formulations with and without tracer. Our results demonstrated that the addition of oil- and water-based tracers do not significantly alter pesticide formulations properties and droplet spectrum, and most likely do not alter the movement of pesticide droplets in the environment.     

新疆阿拉尔垦区大气降尘中重金属时空分布特征

连续12个月对新疆阿拉尔垦区9个样点的3个不同高度处所采集的大气降尘中的重金属含量进行分析,结果表明:所测大气降尘中的5种重金属元素以铁的含量最高,铬的含量最低,其中铜、铁、锰及锌的含量均在4月份达到最大值,并且与降尘量之间有较好的线性关系。在不同的空间范围内,大气降尘中的重金属含量存在显著差异,其中铜、铁、锰的含量均随着高度的上升而呈现递增的趋势;铬的含量随高度的递增呈现递减趋势。     

Reduction of water usage in industry by using the MINLP coordinates technique

Natural resources are limited, so we need to handle them carefully. Wastewater also belongs as a significant natural resource. The re-usage of wastewater is to save fresh water and for the preparation of raw materials or/and utilities. The wastewater re-usage distribution can be optimised using mixed-integer nonlinear programming (MINLP), as a tool in combinations using the coordinates technique. The main goal of this MINLP coordinates technique was: i) wastewater and condensate, as produced during different industrial processes, could be collected for: utilities for steam-generation, and the preparations of raw materials; ii) wastewater and condensate could be collected within the main reservoir; iii) distributions from the main reservoir could be used with including different alternatives, which can reduce pollution, based on the re-usage of wastewater. Alternatives included in the optimization model represent potential solutions, which need to be evaluated on appropriate way.The MINLP coordinates technique for wastewater re-usage distribution was tested on existing formalin and methanol industrial processes, thus allowing the saving of water and generated by 280 kEUR/a profit.     

Distribution of chlorpyrifos in rice paddy environment and its potential dietary risk

Chlorpyrifos is one of the most extensively used insecticides in China. The distribution and residues of chlorpyrifos in a paddy environment were characterized under field and laboratory conditions. The half-lives of chlorpyrifos in the two conditions were 0.9–3.8 days (field) and 2.8–10.3 days (laboratory), respectively. The initial distribution of chlorpyrifos followed the increasing order of water < straw < soil, and soil was characterized as the major absorber. The ultimate residues in rice grain were below the maximum residue limit (MRL) with a harvest interval of 14 days. The chronic exposure for chlorpyrifos was rather low compared to the acceptable daily intake (ADI = 0.01 mg/kg bw) due to rice consumption. The chronic exposure risk from chlorpyrifos in rice grain was 5.90% and 1.30% ADI from field and laboratory results respectively. Concerning the acute dietary exposure, intake estimated for the highest chlorpyrifos level did not exceed the acute reference dose (ARfD = 0.1 mg/kg bw). The estimated short-term intakes (ESTIs) were 0.78% and 0.25% of the ARfD for chlorpyrifos. The results showed that the use of chlorpyrifos in rice paddies was fairly safe for consumption of rice grain by consumers.     

基于MATLAB的城市表层土壤重金属污染空间分布的研究

为全面了解某城市表层土壤重金属污染的空间分布特征,对城市表层土壤中重金属元素As、Cd、Cr、Cu、Hg、Ni、Pb、Zn进行采样分析,采用域法识别特异值进行数据处理。通过Matlab软件,利用克里格法进行空间插值,绘出各重金属浓度与各坐标投影的一维空间分布图,并绘出全城等高地形图,再以数字大小标注样本点的污染浓度,拟合各元素浓度与海拔、平面坐标之间的关系模型,将重金属空间分布特征定量化、模型化。     

陕西省地质灾害简编年表（1950—1992年）

本文扼要记述了陕西1950～1992年重大地质(崩塌、滑坡、泥石流)灾害及发生年代、地点、灾情,为本区国土整治、区域开发提供了基础资料。     

综放采空区防灭火注氮数值模拟与参数确定

用有限元数值方法 ,求解了综放开采采空区注氮情况下的漏风渗流方程和氧浓度渗流耗散方程 ;结合计算机图形技术 ,直观展示了注氮前后采空区流场、流态和氧浓度分布动态变化 ;模拟了在不同注氮量下注氮控制区边界的变化过程 ,得到控制区边界位置与注氮流量呈负指数关系 ;重点探讨了用数值模拟方法确定合理注氮参数 (注氮流量、注氮位置和注氮时间 )的新方法。