室内舒适度评价影响因素的分析

在评价数学模型中引入相似数相似权法,并利用该模型对沈阳市某个装修后的住宅居室进行实例分析,结果表明冬季该居室室内舒适度影响因素贡献程度依次为湿度,苯,受体主观因子,氨,噪声,氡,温度,甲醛,细菌,其中起主导作用的因素是湿度,而且各个因素不是孤立的,它们是相互联系的。     

Distribution,enrichment mechanism and risk assessment for fluoride in groundwater: a case study of Mihe-Weihe River Basin,China

● High fluorine is mainly HCO₃·Cl-Na and HCO₃-Na type. ● F⁻ decreases with the increase of depth to water table. ● High fluoride is mainly affected by fluorine-containing minerals and weak alkaline. ● Fluorine pollution is mainly in the north near Laizhou Bay (wet season > dry season). ● Groundwater samples have a high F⁻ health risk (children > adults). Due to the unclear distribution characteristics and causes of fluoride in groundwater of Mihe-Weihe River Basin (China), there is a higher risk for the future development and utilization of groundwater. Therefore, based on the systematic sampling and analysis, the distribution features and enrichment mechanism for fluoride in groundwater were studied by the graphic method, hydrogeochemical modeling, the proportionality factor between conventional ions and factor analysis. The results show that the fluorine content in groundwater is generally on the high side, with a large area of medium-fluorine water (0.5–1.0 mg/L), and high-fluorine water is chiefly in the interfluvial lowlands and alluvial-marine plain, which mainly contains HCO₃·Cl-Na- and HCO₃-Na-type water. The vertical zonation characteristics of the fluorine content decrease with increasing depth to the water table. The high flouride groundwater during the wet season is chiefly controlled by the weathering and dissolution of fluorine-containing minerals, as well as the influence of rock weathering, evaporation and concentration. The weak alkaline environment that is rich in sodium and poor in calcium during the dry season is the main reason for the enrichment of fluorine. Finally, an integrated assessment model is established using rough set theory and an improved matter element extension model, and the level of groundwater pollution caused by fluoride in the Mihe-Weihe River Basin during the wet and dry seasons in the Shandong Peninsula is defined to show the necessity for local management measures to reduce the potential risks caused by groundwater quality.     

南通市深层地下水中氨氮的影响因素研究

运用相关性分析、因子分析及多元线性回归模型对南通市2020—2021年15个监测井第Ⅲ承压层地下水的监测数据进行分析,研究深层地下水中氨氮的主要影响因素。结果表明,氨氮的主要来源是地下水沉积物中有机质的矿化及一部分工业开采引入的氮污染,地下水的还原性环境是氨氮赋存的主要成因;地下水中As、Fe及总硬度含量的同时增加也能反映氨氮含量的提高;硝态氮（NO-3-N）与NH3-N在深层地下水中是竞争关系,当地下水环境处于还原性时,更易于NH3-N的富集。降低深层地下水中氨氮的主要方法是减少有机污染物输入及还原性废水的入渗。     

环境监测数据质量的影响因素与改进措施研究

提高环境监测数据公信力和权威性,可促进环境管理水平提升、加快推进生态文明建设,对打赢污染防治攻坚战、推动经济社会高质量发展都具有重要意义。本文通过环境监测分布点、采样质量、环境监测仪器、环境监测测试分析方法及环境监测工作人员等几方面因素分析对监测数据质量的影响,根据在实际工作中出现的情况,提出了相应的、有针对性的改进措施,主要从环境监测点位的确定应科学合理、加强实验材料及实验设备的管理、样品的采集与保存应规范明确、环境监测质量分析方法应充分合理及综合提高环境监测工作人员的综合素质等方面进行了阐述。     

Technological disaster factors

Major Hazard Installations (MHIs) deal with the hazardous substances which exceed the threshold quantity. Although MHIs are safe organizations, they cannot fail due to a single error. However, due to their high complexity, the designer and the operator make errors during the design, and operation of the plants. Consequently, the technical, operational and organizational errors may lead to a major accident. The world has seen many incidents due to the operation of the MHIs. Malaysia has experienced several technological disasters. Four investigation reports have been reviewed in detail. This paper reviews the causes of the technological disasters in general. This paper also summarizes the causes of the technological disasters in Malaysia. Finally the paper rearranges the technological disaster causes and errors.     

Experimental investigation of gas explosion in single vessel and connected vessels

Gas explosion in connected vessels usually leads to high pressure and high rate of pressure increase which the vessels and pipes can not tolerate. Severe human casualties and property losses may occur due to the variation characteristics of gas explosion pressure in connected vessels. To determine gas explosion strength, an experimental testing system for methane and air mixture explosion in a single vessel, in a single vessel connected a pipe and in connected vessels has been set up. The experiment apparatus consisted of two spherical vessels of 350 mm and 600 mm in diameter, three connecting pipes of 89 mm in diameter and 6 m in length. First, the results of gas explosion pressure in a single vessel and connected vessels were compared and analyzed. And then the development of gas explosion, its changing characteristics and relevant influencing factors were analyzed. When gas explosion occurs in a single vessel, the maximum explosion pressure and pressure growth rate with ignition at the center of a spherical vessel are higher than those with ignition on the inner-wall of the vessel. In conclusion, besides ignition source on the inner wall, the ignition source at the center of the vessels must be avoided to reduce the damage level. When the gas mixture is ignited in the large vessel, the maximum explosion pressure and explosion pressure rising rate in the small vessel raise. And the maximum explosion pressure and pressure rising rate in connected vessels are higher than those in the single containment vessel. So whenever possible, some isolation techniques, such as fast-acting valves, rotary valves, etc., might be applied to reduce explosion strength in the integrated system. However, when the gas mixture is ignited in the small vessel, the maximum explosion pressures in the large vessel and in the small vessel both decrease. Moreover, the explosion pressure is lower than that in the single vessel. When gas explosion happens in a single vessel connected to a pipe, the maximum explosion pressure occurs at the end of the pipe if the gas mixture is ignited in the spherical vessel. Therefore, installing a pipe into the system can reduce the maximum explosion pressure, but it also causes the explosion pressure growth rate to increase.     

Microbial aerosol particles in four seasons of sanitary landfill site: Molecular approaches, traceability and risk assessment

Landfill sites are regarded as prominent sources of bioaerosols for the surrounding atmosphere. The present study focused on the emission of airborne bacteria and fungi in four seasons of a sanitary landfill site. The main species found in bioaerosols were assayed using high-throughput sequencing. The SourceTracker method was utilized to identify the sources of the bioaerosols present at the boundary of the landfill site. Furthermore, the health consequences of the exposure to bioaerosols were evaluated based on the average daily dose rates. Results showed that the concentrations of airborne bacteria in the operation area (OPA) and the leakage treatment area (LTA) were in the range of (4684 ± 477)–(10883 ± 1395) CFU/m³ and (3179 ± 453)–(9051 ± 738) CFU/m³, respectively. The average emission levels of fungal aerosols were 4026 CFU/m³ for OPA and 1295 CFU/m³ for LTA. The landfill site received the maximum bioaerosol load during summer and the minimum during winter. Approximately 41.39%– 86.24% of the airborne bacteria had a particle size of 1.1 to 4.7 µm, whereas 48.27%– 66.45% of the airborne fungi had a particle size of more than 4.7 µm. Bacillus sp., Brevibacillus sp., and Paenibacillus sp. were abundant in the bacterial population, whereas Penicillium sp. and Aspergillus sp. dominated the fungal population. Bioaerosols released from the working area and treatment of leachate were the two main sources that emerged in the surrounding air of the landfill site boundary. The exposure risks during summer and autumn were higher than those in spring and winter.     

港口起尘影响因素分析及粉尘污染控制措施与建议

介绍了港口粉尘污染类型,港口粉尘污染包括静态污染和动态污染,容易产生粉尘污染的常见固体散货码头有煤炭码头、矿石码头和水泥码头等,对煤炭、矿石等固体散货码头的起尘影响因素进行了分析,不同货物的种类和粒径、含水率、风力及储存方式等均对港口起尘产生影响,从码头和堆场装卸过程、港口物料输送过程、堆场和港区内道路等角度分别介绍了粉尘污染控制措施,对前沿的防尘方式,如防风网和筒仓的抑尘机理及在国内外的应用情况进行了介绍,并从港口选址、平面布置、管理、监测和科研等角度对港口污染防治提出建议。     

总磷总氮在线水质分析仪实际水样测量影响因素分析

总磷总氮在线水质分析仪实际水样测量结果与实验室国标方法测量结果存在着差异,本文分析了影响总磷总氮在线水质分析仪测量结果的因素。     

Removal of dicofol from water by immobilized cellulase and its reaction kinetics

Researches on the removal of dicofol catalyzed by immobilized cellulase were conducted. Factors, such as acidity, temperature, enzyme activity, and initial concentration of dicofol, which could influence the removal were studied. The optimal pH for dicofol removal by immobilized cellulase was approximately 4–7, broader than that for free enzymes. The removal efficiencies for immobilized and free cellulase both decreased with increasing initial concentration of dicofol. The K_m for immobilized cellulase was slightly lower than that of free cellulase, suggesting that substrate affinity may be enhanced by immobilization. The optimum temperatures for immobilized and free cellulase were 45 °C and 50 °C. The removal reaction for immobilized cellulase was found to be a first-order reaction. The activation energy was 64.3 kJ mol⁻¹. The continuous oxidation of dicofol carried out in the static system of immobilized cellulase showed that the removal efficiency of immobilized cellulase remained after six cycles of operation. Thus, the catalytic efficiency of cellulase was improved greatly. As evidenced by infrared and gas chromatography–mass spectrometry data, the mechanism of reaction might involve an attack by the OH free radical of cellulase at a weak location of the dicofol molecule, resulting in the removal of three chlorine atoms from dicofol, thus oxygenizing dicofol and producing 4,4′-dichloro-dibenzophenone.