基于MATLAB的作业场所风险评估

通过对石化企业等高危行业的危险状态或危险出现的概率、暴露于危险环境的频率以及伤害严重度等因素进行安全风险评价,得出整体的风险程度,然后利用MATLAB建立作业场所安全风险评价数学模型,并进行了程序计算,为以后企业作业场所的安全风险评估提供参考.     

基于Verhulst模型的新建隧道顶板下沉预测研究

隧道顶板下沉量预测对隧道安全施工十分重要.通过分析隧道下沉过程,指出其具有"S"型曲线特征,探讨了采用Verhulst模型进行隧道顶板下沉预测的适用性和可行性,并运用MATLAB软件开发相关程序,模拟遵赤高速公路中枢隧道YK39+134.6断面沉降过程,获得相应的预测方程.通过对比其预测结果、回归分析预测结果和实测值,发现该模型的顶板沉降预测值与实测值最接近,证实运用灰色Verhulst模型预测隧道顶板沉降量是合理、可行的.     

Natural and anthropogenic radionuclides in airborne particulate samples collected in Barcelona (Spain)

Results for naturally occurring ⁷Be, ²¹⁰Pb, ⁴⁰K, ²¹⁴Bi, ²¹⁴Pb, ²¹²Pb, ²²⁸Ac and ²⁰⁸Tl and anthropogenic ¹³⁷Cs in airborne particulate matter in the Barcelona area during the period from January 2001 to December 2005 are presented and discussed. The ²¹²Pb and ²⁰⁸Tl, ²¹⁴Bi and ²¹⁴Pb, ⁷Be and ²¹⁰Pb radionuclide levels showed a significant correlation with each other, with correlation coefficients of 0.99, 0.78 and 0.69, respectively, suggesting similar origin/behaviour of these radionuclides in the air. Caessium-137 and Potassium-40 were transported to the air as resuspended particle from the soil. The ⁷Be and ²¹⁰Pb concentrations showed similar seasonal variations, with a tendency for maximum concentrations during the summer months. An inverse relationship was observed between the ⁷Be, ²¹⁰Pb, ⁴⁰K and ¹³⁷Cs concentrations and weekly rainfall, indicating washout of atmospheric aerosols carrying these radionuclides.     

Temporal variation of Be concentrations in atmosphere for 8 y from 2000 at Yamagata,Japan: solar influence on the Be time series

We have been continuously observing the daily ⁷Be concentrations in surface air at Yamagata, Japan (38.25° N, 140.35° E) since 2000. The yearly profile of the ⁷Be concentration indicates the variation in galactic cosmic rays owing to solar modulation. Over 8 y, the ⁷Be concentration, cosmic neutrons, and number of sunspots varied by 37.4%, 12.2%, and 92.8%, respectively. The influence of precipitation on the ⁷Be variability was approximately 5%. Hence, the yearly ⁷Be concentration was mainly varied by the solar modulation of the ⁷Be production rates. Based on the production rates found in an EXPACS simulation, the observed variability indicates ⁷Be transport from high latitudes. The daily ⁷Be concentrations have two significant periodic components of 19 d and 36 d. The 36-d component implies a relationship between the sun's rotation and the vertical transport of air masses under quiet solar activity.     

Beryllium-7 atmospheric deposition and sediment inventories in the Neponset River estuary,Massachusetts, USA

Measured monthly atmospheric depositional fluxes of cosmogenically produced ⁷Be ranged from 1 to 67 mBq/cm² in Boston, Massachusetts between September 2000 and August 2007. These fluxes exhibited seasonality and supported a decay-corrected ⁷Be atmospheric depositional running inventory that ranged from 36 to 144 mBq/cm². Annual ⁷Be deposition exhibited an increasing trend that may reflect a general decrease in solar activity and a general increase in precipitation over the 7-year sampling period. To investigate short-term sediment dynamics and accumulation patterns in the Neponset River estuary, we collected six sediment cores in July 2006 and measured ⁷Be sediment inventories ranging from 48 to 546 mBq/cm² Comparisons of these sediment inventories with the ⁷Be running inventory from atmospheric deposition (101 mBq/cm²) at the time of core collection indicated a large degree of spatial heterogeneity in sediment accumulation patterns and its potential use as a tool for assessing the impacts of environmental restoration activities in estuarine environments.     

Effects of collector types in sampling of atmospheric depositional fluxes

The bulk gross alpha, gross beta and ⁷Be depositional fluxes were measured in Málaga (36.7°N, 4.5°W), a coastal Mediterranean station in the south of Spain for one whole year. In order to quantify the local variation of deposition rates, we have analysed the monthly results from two deposition collectors: a “pot “collector with a continuous water-covered surface and a “funnel” collector. In general, the alpha and beta depositional fluxes from the funnel collector were approximately two times lower than the pot collector. Whereas for the cosmogenic ⁷Be, the depositional flux of ⁷Be from funnel collector was also approximately two times lower than the pot collector. A good correlation of the depositional flux of ⁷Be has been obtained from both collectors.     

气液混合脉冲放电体系中偶氮染料的脱色效果

为了深入探究水包气式气液混合脉冲放电体系中各参数对有机物降解效果的影响,建立了多针一板电极形式的气液混合脉冲放电等离子体体系,以典型的偶氮染料——酸性橙Ⅱ（A07）为目标物,考察该体系中影响染料脱色效果的关键因素。研究结果表明,气液混合脉冲放电体系中与脉冲电源输入功率有关的因素（脉冲电压峰值和脉冲频率）对A07脱色效果影响明显。随着脉冲电压峰值和脉冲频率的增加,A07溶液的脱色效率和相应的准一级降解动力学常数增加。在较高的脉冲电压峰值（30kV）和脉冲频率（75Hz）条件下,10mg／LA07溶液的脱色效率和准一级降解动力学常数分别达到r92．7％和3．50×10～／min。同时,研究证明酸性溶液条件较利于染料脱色。     

The effect of air mass origin on the ambient concentrations of Be and Pb in Islamabad, Pakistan

Concentration of radionuclides ²¹⁰Pb and ⁷Be, having half lives of 22.3 years and 53.29 days, respectively, in the surface air samples of Islamabad (33.38° N, 73.10° E and Altitude ∼536 m asl.) are measured. The non-destructive technique of gamma-spectrometry, with a high purity germanium HPGe detector, was employed for the analysis of all samples. The annual average concentrations of ²¹⁰Pb and ⁷Be in the surface air samples were determined as 0.284 ± 0.15 and 3.171 ± 1.14 mBq m⁻³, respectively. Our results have shown a seasonal variation of the concentration of ⁷Be in air samples with high values for the spring season. High concentrations for ²¹⁰Pb are obtained when air masses originate from plain areas of Pothohar region, located in the South-West, West and North West of Islamabad. Our values of concentrations show a nice agreement with the relevant reported results.     

Fluorinated alkyl compounds including long chain carboxylic acids in wild bird livers from Japan

A wide range of fluorinated alkyl compounds (FACs) has been reported in wildlife in various locations in the world. However, such information regarding Japanese wildlife is rarely found. In the present study, we investigated the occurrence of 21 FACs, including perfluorinated alkyl sulfonates (PFASs), perfluorinated carboxylates (PFCAs), and fluorotelomer acids, in the livers of 10 wild bird species from two regions in northern Japan. To avoid interferences, FACs were quantified by a recently developed method using acetonitrile and solid-phase extraction followed by an ion exchange HPLC column separation. Apart from perfluorooctane sulfonate (PFOS), which was found at the highest levels of all the compounds detected, several long chain perfluorinated carboxylates (PFCAs) from C8 to C16, particularly perfluorotetradecanoic acid (PFTeDA) and perfluorohexadecanoic acid (PFHxDA), were detected for the first time. Additionally, 7:3 FTCA, a fluorotelomer acid, was also detected in most swan livers from Miyagi prefecture and all the birds from Tochigi prefecture. However, none of the sulfonamides and unsaturated telomer acids were detected in any species. Swans seem to be the least exposed wild birds to FACs among the investigated birds, signifying that feeding habits may reflect FAC accumulation in wild birds. The highest total concentration of detected FACs was 405 ng g⁻¹ wet wt., which was found in a Japanese sparrowhawk, indicating that the top predatory wild birds can accumulate several long chain carboxylic acids. However, the current FAC concentrations found in livers may suggest that these compounds alone would not cause a severe toxic effect in these species.     

Assessment of pollution along the Northern Iberian shelf by the combined use of chemical and biochemical markers in two representative fish species

Muscle concentrations of organochlorinated compounds as well as biliary levels of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APEs) were determined in two different fish species, the four-spotted megrim (Lepidorhombus boscii) and the pouting (Trisopterus luscus) collected along the Northern Iberian coast. Additionally, a set of biochemical markers namely, 7-ethoxyresorufin O-deethylase (EROD), UDP-glucuronosyltransferase (UGT) and catalase (CAT) were measured in liver subcellular fractions. Chemical analysis indicated geographical differences in pollutant loads that were further reinforced by biomarker responses. Thus, EROD activity showed a good correlation with the amount of PCBs bioaccumulated in muscle tissue of both fish species. Elevated UGT activity was observed in those individuals highly exposed to APEs and 1-naphthol. The study reinforces the need to select representative sentinel species from different habitats for biomonitoring purposes and provides further support for the use of biomarkers in assessing the health of coastal areas.