基层环境监察工作的现状及措施

基层环境监察工作是环境保护工作的重要环节。本文针对基层环境监察工作的现状和存在的主要问题进行了简要分析,根据部分地区基层环境监察部门的成功经验,并就如何提高基层环境监察水平提出了一些具体措施和方法,对从事环境监察的人员有着一定的参考价值和借鉴意义。     

Seasonal,diurnal and nocturnal variations of carbonyl compounds in the semi-urban environment of Orléans,France

Atmospheric carbonyls were measured at a semi-urban site in Orléans, France, from October 2010to July2011. Formaldehyde, acetaldehyde and acetone were found to be the most abundant carbonyls, with average concentrations of 3.1, 1.0, 2.0 ppb, respectively in summer, 2.3, 0.7, 2.2 ppb, respectively in autumn, 2.2, 1.0, 2.1 ppb, respectively in spring,and 1.5, 0.7, 1.1 ppb, respectively in winter. Photo-oxidation of volatile organic compounds(VOCs) was found to make a remarkable contribution to atmospheric carbonyls in the semi-urban site based on the distinct seasonal and diurnal variations of the carbonyls, as well as the significantly positive correlations between the carbonyls and ozone. The significantly negative correlations between NO x and O_3 as well as the carbonyls and the positive correlations between wind speed and O_3 as well as the carbonyls implied that the carbonyls and O_3 at the semi-urban site were probably formed during air mass transport from neighboring cities.     

Practical aspects of occupational EMF exposure assessment

Electromagnetic fields exposure assessment methodology is briefly presented. The basic problems defined for the practical use of electromagnetic fields measurements and numerical calculations carried out for workers exposure assessment in real occupational situations are discussed. The examples of data from real workplace are presented, focusing: spatial distribution of electromagnetic fields affecting worker’s body, complex characteristics of the frequency content, workers activities/moving in the workplace, field impedance, etc. The situation when the use of calculations is required is discussed. The basic requirements for workers exposure assessment protocols are presented. The possible range of the use of internal and external measures of exposure level is also discussed.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Temperature dependence of the absolute rate constant for the reaction of ozone with dimethyl sulfide

Absolute rate constants for the reaction of ozone with dimethyl sulfide (DMS) were measured in a 200-L Teflon chamber over the temperature range of 283-353 K. Measurements were carried out using DMS in large excess over ozone of 10 to 1 or greater. Over the indicated temperature range,the data could be fit to the simple Arrhenius expression as KDMS = (9.96±3.61)×10-11exp(-(7309.7±1098.2)/T)cm3/(molecule·s). A compared investigation of the reaction between ozone and ethene had a kc2H4 value of(1.35±0.11)×10-18 cm3/(molecule·s) at room temperature.     

Geometrical characteristics of externally venting flames: Assessment of fire engineering design correlations using medium-scale compartment-façade fire tests

In a fully developed under-ventilated compartment fire, flames may spill out of external openings (e.g. windows); Externally Venting Flames (EVF) pose a significant risk of fire spreading to adjacent floors or buildings. The main aim of this work is to comparatively assess a range of fire engineering design correlations used to describe the external dimensions of the EVF envelope. The predictive accuracy of each correlation is evaluated through comparison with experimental data obtained in a medium-scale compartment-façade fire facility, using typical fire loads suggested in the Eurocode. A series of fire tests is performed, employing a ¼ scale model of the ISO 9705 room, equipped with an additional extended façade. An “expendable” fuel source (n-hexane) is utilized to effectively simulate realistic building fire conditions. An extensive sensor network is used to monitor the dynamic behaviour of a broad range of important EVF physical parameters and a dedicated image processing tool is developed to allow estimation of the EVF envelope main dimensions (e.g. height, width, projection). Digital camera imaging is used to determine the main geometrical characteristics of the EVF envelope. Comparison of fire engineering design correlation predictions with experimental data reveals that correlations for the estimation of EVF height err on the safe side in under-ventilated fire conditions; decreasing the fire load results in under-prediction of EVF height and projection. It is shown that EVF projection and width strongly depend on both excess heat release rate and height. In addition, the necessity to derive appropriate criteria for the identification of the EVF projection is demonstrated. The obtained extensive set of experimental data, covering three different fire load levels, can be also used to validate numerical simulation tools or evaluate the accuracy of other available fire design correlations.     

氮氧化物的污染控制对策

详细地介绍了日本针对不同的排放源－－固定源和流动源－－所采取的氮氧化物污染控制对策。对固定源，在实施全国统一的排放标准的基础上，对于一些工厂相对集中、污染问题严重的地区实施总量控制，同时积极促进技术革新以及降低氮氧化物的排放；对流动源所采取的措施有，确定不同车型汽车排放尾气递减的短期目标和长期目标，实施汽车氮氧化物法，积极推进低公害车的普及。通过采取上述措施，在日本，固定源排放的氮氧化物得到了较好     

Measurements of human exposure from emerging wireless technologies

The rapid development of wireless technologies leads to increased human exposure to electromagnetic fields from new devices. Most of these technologies communicate in short to medium range. Communication devices, such as mobile phones (GSM, UMTS, LTE) and wireless computer networks (WLAN, HSDPA, WIMAX) usually work at distances up to some 10 km. Other techniques like Bluetooth, RFID, and wireless USB work at distances up to a few meters. RFID systems can use several frequency bands from low frequencies up to microwaves. The other technologies are mainly using microwave frequencies. Most of these technologies have a rather low-output power, typically <1 W average power, except for fixed transmitters like base stations. This means that the exposure from distant sources is low. If the devices are kept close to the body, the local exposure can be in the range of the levels in the ICNIRP recommendation; this is the case, for example, for mobile phones and WLAN transmitters in laptops. For distant sources, there exist several measurement techniques such as spectrum analysers, measurement receivers, and broadband meters. For sources used close to the body, the local SAR levels have to be determined. For this purpose, instruments measuring the local electric field inside body phantoms have been developed. An alternative to measurements is numerical simulations. If one has knowledge of the signal characteristics of the different technologies then it is possible to find a suitable measurement technique to assess the human exposure.     

投影角度受限制的超声波CT温度测量

本研究在投影角度受限制的情况下利用超声波CT完成三维温度测量。新CT再构成算法的主要特征如下：在考虑到投影数据之间的相关性的同时、在傅里叶变换基础之上利用外插手法来补全不完整的投影数据。我们运用计算机模拟计算以及建立实验系统对上述算地的可靠性进行检验。根据计算机模拟计算和实验的结果,我们认为本研究所提出的CT算法可以有效地处理受投影角度限制的投影数据。     

受限透视角度下超声波CT温度场诊断技术

超声波CT一种热测量方法,具有不接触、对温度场不干扰的优点。本文发展一种新的超声波CT再现方法,用于解决受限透视角度所产生的信息量不足的问题。新的超声波CT再现算法建立在逆矩阵变换的基础上,它不同于通常的采用SL过滤器的所谓FBPCT再现方式。论文中描述了三种CT迭代再现算法,用计算机模拟结果和三维温度场测量实验数据验证了再现算法的可靠性。同时根据计算和实验结果,建议在受限的透视角度情况下,迭代方法采用修正的正则最小二乘法CGM是合适的。