Simulated seasonal variations in wet acid depositions over East Asia

The air quality modeling system Regional Atmospheric Modeling System-Community Multi-scale Air Quality (RAMS-CMAQ) was applied to analyze temporospatial variations in wet acid deposition over East Asia in 2005, and model results obtained on a monthly basis were evaluated against extensive observations, including precipitation amounts at 704 stations and SO4(2-), NO3-, and NH4+ concentrations in the atmosphere and rainwater at 18 EANET (the Acid Deposition Monitoring Network in East Asia) stations. The comparison shows that the modeling system can reasonably reproduce seasonal precipitation patterns, especially the extensive area of dry conditions in northeast China and north China and the major precipitation zones. For ambient concentrations and wet depositions, the simulated results are in reasonable agreement (within a factor of 2) with observations in most cases, and the major observed features are mostly well reproduced. The analysis of modeled wet deposition distributions indicates that East Asia experiences noticeable variations in its wet deposition patterns throughout the year. In winter, southern China and the coastal areas of the Japan Sea report higher S04(2-) and NO3- wet depositions. In spring, elevated SO4(2-) and NO3-wet depositions are found in northeastern China, southern China, and around the Yangtze River. In summer, a remarkable rise in precipitation in northeastern China, the valleys of the Huaihe and Yangtze rivers, Korea, and Japan leads to a noticeable increase in SO4(2-) and NO3- wet depositions, whereas in autumn, higher SO4(2-) and NO3-wet depositions are found around Sichuan Province. Meanwhile, due to the high emission of SO2, high wet depositions of SO4(2-) are found throughout the entire year in the area surrounding Sichuan Province. There is a tendency toward decreasing NO3- concentrations in rainwater from China through Korea to Japan in both observed and simulated results, which is a consequence of the influence of the continental outflow from Eurasia. The same tendency is not found for SO4(2-).     

错流涡旋式高效固液分离器内固液两相流的数值模拟

介绍设计制作的一种新型错流涡旋式高效固液分离装备,利用离散相模型对其进行数值模拟,得到此分离装置的三维液相流场分布、离散相砂粒的运行轨迹以及砂粒的去除效率,明确了其沉淀特征。其结论对于优化错流涡旋式高效固液分离器的设计具有参考价值。     

Exposure to metal mixtures and human health impacts in a contaminated area in Nanning, China

Cadmium and lead have been identified as very toxic metals, which are widely present in the environment due to natural and anthropogenic emissions. Many studies have shown that the food chain is the main pathway of cadmium and lead transfer from the environment to humans. It is well documented that many factors will affect their transfer through food chains. Previous investigations on heavy metals were mostly concentrated on one contaminant in isolation. However, in real environments, exposure to mixtures of metals is ubiquitous such that cadmium pollution is invariably being associated with lead and zinc, etc. This study focuses on the contamination and health effects of the metal mixtures. For this purpose, a dietary survey was taken for 3 groups in Nanning in October 2002. Samples of soils, plants (vegetables), urine and blood of humans were measured for Cd, Fe, Cu, Zn, Ca and Pb, in addition, the urinary indicators of renal dysfunction Albumin (ALB), N-acetyl-beta-D-glucosaminidase (NAG), Beta-2-microglobulin (beta2-MG) and Retinol-binding protein (RBP) in urine were also measured. Results showed that soil contamination with metal mixtures had caused significant renal dysfunction of the local residents living in the contaminated area, and the dose-response curve was somewhat altered by the mixed contamination of Cd and Pb as well as the intake of other minerals. The importance of mixtures of metal contamination and human health are also discussed in this paper.     

Marine Radar Oil-Spill Monitoring through Local Adaptive Thresholding

Marine oil spills affect the environment, economy, and quality of life for coastal inhabitants. This article presents a method of X-band marine radar oil-spill identification by considering the marine radar images of the 2010 Dalian 7-16 accident. The Prewitt operator was improved and a linear interpolation was proposed to suppress co-channel interferences. In addition, a model of a gray-intensity-correcting matrix is proposed to smooth a whole image, thus displaying the oil film more intuitively. Furthermore, a contrast-limited adaptive histogram equalization method was used to increase the contrast inside and outside the oil film. Moreover, the local adaptive thresholding method was improved to segment the oil spills. The results show that the proposed method is an improvement on similar previous approaches for this task when employing X-band marine radar images. The proposed method can provide technical and theoretical bases for emergency response, damage assessment, and liability identification of oil spills.     

从粉煤灰中回收氧化铝

简要介绍了国外从粉煤灰中回收氧化铝的几种方法，着重研究了煅烧／稀酸过滤法影响氧化铝回收率的各种因素。     

社会组织参与区域合作治理进化博弈模型

社会多元化与公民社会的快速发展,促使社会组织参与社会治理和应急响应的诉求与能力日益加强,驱动着政府职能变革和区域治理方式创新。区域合作治理过程中,治理主体依据情景态势调整策略,影响其他主体的治理收益和策略选择,形成复杂的动态博弈关系。本文把握政府与社会组织的动态博弈行为特征,确定区域合作治理的博弈支付矩阵与复制动态方程,构建区域政府与社会组织合作治理进化博弈模型。分析得出5个可能的均衡点,通过雅可比矩阵分析均衡点的稳定性,可知政府与社会组织合作治理进化博弈的长期稳定策略集为{(合作,合作),(不合作,不合作)}。模型结果分析表明,合作收益直接影响着博弈稳定策略的进化方向,收益大于成本是政府与社会组织选择合作策略的必要条件,任一方的合作收益小于成本,选择独立行动是双方的占优策略,最终的策略选择与政府和社会组织合作所获取的超额收益、支付成本及合作水平密切相关。合作超额收益增加或合作水平提升时,博弈系统向(合作,合作)演化的概率加大;合作成本增加时,博弈系统向(不合作,不合作)演化的概率加大。制度规范不健全、组织信任缺失、社会组织力量薄弱等因素影响进化均衡结果,社会组织创新发展氛围尚未形成、自组织性和自律性内生动力不足,是制约社会组织参与合作治理的关键问题。基于此,提出社会组织参与区域合作治理的协调机制及培育机制,具体策略包括:明确权责关系、畅通参与渠道、创新合作形式,以及优化管理制度、让渡成长空间和树立社会公信。     

Chemical content and source apportionment of 36 heavy metal analysis and health risk assessment in aerosol of Beijing

The concentration levels of 36 airborne heavy metals and atmospheric radioactivity in total suspended particulate (TSP) samples were measured to investigate the chemical characteristics, potential sources of aerosols, and health risk in Beijing, China, from September 2016 to September 2017. The TSP concentrations varied from 6.93 to 469.18 μg/m³, with a median of 133.97 μg/m³. The order for the mean concentrations of heavy metals, known as hazardous air pollutants (HAPs), was as follows: Mn > Pb > As > Cr > Ni > Se > Cd > Co > Sb > Hg > Be; Non-Designated HAPs Metals: Ca > Fe > Mg > Al > K > Na > Zn > P > Ba > Ti > Cu > Sr > B > Sn > I > V > Rb > Ce > Mo > Cs > Th > Ag > U > Pt. The median concentration of As was higher than China air quality standard (6 ng/m³). The gross α and β concentration levels in aerosols were (1.84?±?1.59) mBg/m³ and (1.15?±?0.85) mBg/m³, respectively. The enrichment factor values of Cu, Ba, B, Ce, Tl, Cs, Pb, As, Cd, Sb, Hg, Fe, Zn, Sn, I, Mo, and Ag were higher than 10, which indicated enriched results from anthropogenic sources. Pb, As, and Cd are considered to originate from multiple sources; fireworks released Ba during China spring festival; Fe, Ce, and Cs may come from stable emissions such as industrial gases. The health risks from anthropogenic metals via inhalation, ingestion, and dermal pathway were estimated on the basis of health quotient as well as the results indicated that children faced the higher risk than adults during the research period. For adults, the health risk posed by heavy metals in atmospheric particles was below the acceptable level.

     

Microbial abundance and community in subsurface flow constructed wetland microcosms: role of plant presence

In this research, the role of plants in improving microorganism growth conditions in subsurface flow constructed wetland (CW) microcosms was determined. In particular, microbial abundance and community were investigated during summer and winter in Phragmites australis-planted CW microcosms (PA) and unplanted CW microcosms (control, CT). Results revealed that the removal efficiencies of pollutants and microbial community structure varied in winter with variable microbial abundance. During summer, PA comprised more dominant phyla (e.g., Proteobacteria, Actinobacteria, and Bacteroidetes), whereas CT contained more Cyanobacteria and photosynthetic bacteria. During winter, the abundance of Proteobacteria was >40 % in PA but dramatically decreased in CT. Moreover, Cyanobacteria and photosynthetic bacterial dominance in CT decreased. In both seasons, bacteria were more abundant in root surfaces than in sand. Plant presence positively affected microbial abundance and community. The potential removal ability of CT, in which Cyanobacteria and photosynthetic bacteria were abundant during summer, was more significantly affected by temperature reduction than that of PA with plant presence.     

Wetting properties and performance test of modified rigid collector in wet electrostatic precipitators

The fine particles are considered a significant pollution problem. The wet electrostatic precipitators (ESPs) have advantages of efficient collection of the fine particles with lower pressure drop and eliminating reentrainment. The wetting properties of the collector surfaces have significantly important effect on wet ESPs’ stable and secure operation. The modified rigid collector (MRC) was modified by coating specific vinyl ester resin composites and loose glass fiber cloth over the conventional carbon steel in a certain way. The rigid collector surfaces before and after modification had been characterized by scanning electron microscopy (SEM) and interface tensiometer. The effect of operating temperatures on the wetting properties of the rigid collector surfaces before and after modification was investigated. The temperature range was 40~90 °C, and the wetting properties contained liquid holdup, surface flow rate, film rate, average film thickness, and critical saturation time. The modified rigid collector surface exhibited excellent wetting properties at the operating temperatures. The fine particles collection performance compared among the MRC, the conventional rigid collector (CRC), and the flexible collector (FC) in the wet ESPs was investigated. The effects of the applied voltage, the water film, corona power, and the specific collecting area on the fine particles collection were evaluated. The modified rigid collector provided high fine particles collection effect with lower energy and water consumption.

Implications: To improve the submicron particles collection efficiency and decrease energy and water consumption, the formation of uniform water film over the collector surfaces has been widely studied. The modified rigid collector was modified by coating specific vinyl ester resin composites and loose glass fiber cloth (ERGF) over the conventional carbon steel (CCS) in a certain way. The modified rigid collector surface exhibited excellent wetting properties. The wet ESPs by the modified rigid collector exhibited significantly higher particles collection efficiency than by the conventional rigid collector.     

Titanium dioxide nanoparticles relieve biochemical dysfunctions of fifth-instar larvae of silkworms following exposure to phoxim insecticide

Phoxim insecticide is widely used in agriculture, which is toxic to insect pests and nontarget organisms. The phoxim poisoning is hard to prevent for silkworms. TiO₂ NPs have been widely applied in whitening, brightening foods, toothpaste or sunscreens, and orally-administered drugs. However, whether TiO₂ NPs can increase resistance of silkworm to phoxim poisoning has not been reported. The results demonstrated that added TiO₂ NPs significantly decreased reduction of protein, glucose and pyruvate contents, lactate dehydrogenase, succinate dehydrogenase and malate dehydrogenase activities, and attenuated increases of free amino acids, urea, uric acid and lactate levels, activities of protease, alanine aminotransferase and aspartate aminotransferase in the hemolymph of silkworms caused by phoxim exposure. From the present study, it is clearly evident that added TiO₂ NPs may relieve toxic impacts of phoxim insecticide on silkworm metabolism, which in turn may result in an increase in silk yield.