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.     

催化动力学光度法测定水中痕量亚硝酸根

根据盐酸介质中亚硝酸根对甲基红的溴酸钾氧化反应的催化作用,建立了测定水中痕量亚硝酸根的催化动力学光度法。实验结果表明,当盐酸溶液的加入量为1.0mL、溴酸钾溶液的加入量为0.2mL、甲基红溶液的加入量为3.5mL、加热时间为5min、加热温度为50℃时,方法的检出限为1.0×10-7g/L,线性范围为5.0×10-7~1.0×10-5g/L,回收率为97.8%~103.3%,相对标准偏差为1.8%~2.6%。该法已用于废水水样中亚硝酸根的测定,结果满意。     

用微电极测定曝气量对SBR系统中硝化作用的影响

为了研究曝气量对硝化作用的影响,实验采用3个相同的SBR装置,分别在曝气量为4、10和16 L/h的条件下处理人工污水,并采用自制的溶解氧、NO3-、NH4+和pH微电极测定了活性污泥絮体内部微元环境中相应基质的浓度。结果表明,曝气量为4 L/h时,活性污泥絮体内存在厌氧微区,NO3--N浓度减小了,发生了反硝化作用;而曝气量为10 L/h和16 L/h时,活性污泥絮体内发生的都是硝化反应,且NH4+-N浓度的减小量、NO3--N浓度的增大量都随着曝气量的增大而增大,pH随着曝气量的增大而减小。     

基于社会网络的高校不安全因素影响机制及安全管理研究

为了探索影响高校不安全的因素及影响机制,提升高校管理水平,采用文献分析和问卷调查的方法建立基于个体、环境和管理因素间的关系概念模型。运用社会网络分析（SNA）构建关系网络模型,分析其结构与节点特性等情况并提出相应建议。研究结果表明:利用社会网络分析方法分析高校不安全因素关系问题可信度高,不安全因素间存在一定的影响关系,影响力最大的因素为高校扩招;关键不安全因素包括安全排查不全面、高校安全监管与奖惩制度不合理等;关键不安全因素可构成连锁反应链,高校安全排查不全面,导致高校安保制度不健全,进而校园周边环境复杂化;不安全因素网络的桥节点包括高校安全监管与奖惩制度不合理等,桥节点可连接反应链形成不安全因素网络。研究结果能帮助高校针对关键不安全因素进行管理,从而减少事故的发生。     

煤矿安全生产的特性

近几年,从我国各类事故统计中分析,煤矿安全事故是仅次于事故“老大”的道路交通,煤矿安全形势非常严峻。我们仅以2006年为例,2006年我国煤矿事故死亡4746人。煤矿百万吨死亡率为2．041,达到了历史最好水平。全国煤矿共发生瓦斯事故327起,死亡1319人,