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91.
Polaroid Corporation is committed to a policy of respect for the environment. Each division is charged with responsibility to achieve environmental goals for compliance, toxic use and waste reduction, and community outreach. This article shows how a major manufacturing division is now striving to meet new compliance demands by combining strategic planning and Total Quality techniques.  相似文献   
92.
93.
From June 2013 to March 2015, in total 41 passive sampler deployments of 2 wk duration each were conducted at 17 sites in South Philadelphia, PA, with results for benzene discussed here. Complementary time-resolved measurements with lower cost prototype fenceline sensors and an open-path ultraviolet differential optical absorption spectrometer were also conducted. Minimum passive sampler benzene concentrations for each sampling period ranged from 0.08 ppbv to 0.65 ppbv, with a mean of 0.25 ppbv, and were negatively correlated with ambient temperature (–0.01 ppbv/°C, R2 = 0.68). Co-deployed duplicate passive sampler pairs (N = 609) demonstrated good precision with an average and maximum percent difference of 1.5% and 34%, respectively. A group of passive samplers located within 50 m of a refinery fenceline had a study mean benzene concentration of 1.22 ppbv, whereas a group of samplers located in communities >1 km distant from facilities had a mean of 0.29 ppbv. The difference in the means of these groups was statistically significant at the 95% confidence level (p < 0.001). A decreasing gradient in benzene concentrations moving away from the facilities was observed, as was a significant period-to-period variation. The highest recorded 2-wk average benzene concentration for the fenceline group was 3.11 ppbv. During this period, time-resolved data from the prototype sensors and the open-path spectrometer detected a benzene signal from the west on one day in particular, with the highest 5-min path-averaged benzene concentration measured at 24 ppbv.

Implications: Using a variation of EPA’s passive sampler refinery fenceline monitoring method, coupled with time-resolved measurements, a multiyear study in South Philadelphia informed benzene concentrations near facilities and in communities. The combination of measurement strategies can assist facilities in identification and mitigation of emissions from fugitive sources and improve information on air quality complex air sheds.  相似文献   

94.
The Australian Air Quality Forecasting System (AAQFS) is one of several newly emerging, high-resolution, numerical air quality forecasting systems. The system is briefly described. A public education application of the air quality impact of motor vehicle usage is explored by computing the concentration and dosage of particulate matter less than 10 microm in aerodynamic diameter (PM10) for a commuter traveling to work between Geelong and Melbourne, Victoria, Australia, under "business-as-usual" and "green" scenarios. This application could be routinely incorporated into systems like AAQFS. Two methodologies for calculating the dosage are described: one for operational use and one for more detailed applications. The Clean Air Research Programme-Personal Exposure Study in Melbourne provides support for this operational methodology. The more detailed methodology is illustrated using a system for predicting concentrations due to near-road emissions of PM10 and applied in Sydney.  相似文献   
95.
被称为安全识别设备“苦力”的卡片打印机现在已经步入了一个新的发展阶段。在用户需求的驱使下,卡片打印机的应用已经超越了传统的安全范畴,其打印速度更快,设备更加智能,操作方式更加简便,而与之相伴的却是单位价格的逐年下降。 以得克萨斯州的一家娱乐公园为例,如果某人需要马上购买一张该园的出入卡,而且想在购买之日就开始使用,那么就可以用卡片打印机来完成这  相似文献   
96.
Fundamental trade-offs generating the worldwide leaf economics spectrum   总被引:5,自引:0,他引:5  
Recent work has identified a worldwide "economic" spectrum of correlated leaf traits that affects global patterns of nutrient cycling and primary productivity and that is used to calibrate vegetation-climate models. The correlation patterns are displayed by species from the arctic to the tropics and are largely independent of growth form or phylogeny. This generality suggests that unidentified fundamental constraints control the return of photosynthates on investments of nutrients and dry mass in leaves. Using novel graph theoretic methods and structural equation modeling, we show that the relationships among these variables can best be explained by assuming (1) a necessary trade-off between allocation to structural tissues versus liquid phase processes and (2) an evolutionary tradeoff between leaf photosynthetic rates, construction costs, and leaf longevity.  相似文献   
97.
Emission rates of ammonia, acid gases, inorganic aerosols, methane, and size fractionated particulate matter were measured from a commercial broiler facility. This paper discusses the statistically influential parameters on numerous pollutants’ emission from a broiler chicken facility and generates emission correlations to fill data gaps and develop averaged emission factors.Live mass of the birds was commonly a significant variable to each pollutant’s emission. Some variables significantly impacted the pollutants’ emissions, such as litter moisture content, but were measured discretely and cannot be used for filling in data gaps.House parameter correlations were, therefore, developed using parameters measured at the facility, such as indoor temperature, relative humidity, and the live mass of the birds, and relied on the mutual behaviour of discretely measured explanatory parameters and continuously monitored confounding variables. The live mass and the difference in the indoor temperature and the house set-point temperature were the most significant variables in each pollutant’s correlation.The correlations predicted each pollutants emission to within 20% (total mass basis) over most broiler production cycles. Their validation on independent datasets also successfully estimated the flocks’ emissions to within 3%.Emission factors (EFs) were developed for methane, ammonia, and size fractionated particulate matter using measured data and correlated emissions to fill in data gaps. PM10 (particulate matter ≤10 microns) EFs were estimated to be 4.6 and 5.9 g d?1 [Animal Unit, AU]?1 for five and six week production cycles, respectively. PM2.5 (PM ≤ 2.5 microns) EFs were 0.8 and 1.4 g d?1 AU?1 for five and six week cycles, respectively. Ammonia and methane emission factors were estimated at 120.8 and 197.0 g d?1 AU?1, respectively for a five week production cycle.  相似文献   
98.
Meunier L  Koch I  Reimer KJ 《Chemosphere》2011,84(10):1378-1385
Dissolution kinetics of arsenic from soils and tailings were studied under simulated gastrointestinal conditions to determine the effects of residence time, pH and soil composition on the bioaccessibility of arsenic. The samples were sieved to four particle size fractions from bulk to <45 μm, and included arsenic minerals, soils and tailings with total arsenic concentrations ranging from 19 to 420 00 mg kg−1. The bioaccessible arsenic concentrations varied from 2.8 to 10 000 mg kg−1, and the highest concentrations were associated with the smallest particle size fractions. Kinetic parameters were determined for each sample extracted under gastric conditions (pH = 1.8) followed by intestinal conditions (pH = 7.0). Under gastric pH conditions, dissolution appeared to be diffusion-controlled and followed an exponential curve, whereas a logarithmic or linear model was used to describe the mixed dissolution mechanisms observed under intestinal conditions. Nine of the 13 samples tested reached a steady state bioaccessible arsenic concentration within the 5-h physiologically-based extraction test (PBET). However the bioaccessible arsenic concentrations in four tailings samples increased significantly (= 0.034) between the 5-h and the extended 24-h extraction under intestinal conditions. Since arsenic absorption may occur along the entire digestive tract, assessments based on the standard 5-h PBET extraction may not adequately estimate the risks associated with arsenic absorption in such cases. The slow dissolution kinetics associated with secondary arsenic minerals in some tailings samples may require extending the PBET extractions to longer periods, or extrapolating using the proposed kinetic models, to reach steady state concentrations in simulated gastrointestinal fluids.  相似文献   
99.
Arsenic-contaminated soils may pose a risk to human health. Redevelopment of contaminated sites may involve amending soils with organic matter, which potentially increases arsenic bioaccessibility. The effects of ageing on arsenic-contaminated soils mixed with peat moss were evaluated in a simulated ageing period representing two years, during which arsenic bioaccessibility was periodically measured. Significant increases (p = 0.032) in bioaccessibility were observed for 15 of 31 samples tested, particularly in comparison with samples originally containing >30% bioaccessible arsenic in soils naturally rich in organic matter (>25%). Samples where percent arsenic bioaccessibility was unchanged with age were generally poor in organic matter (average 7.7%) and contained both arsenopyrite and pentavalent arsenic forms that remained unaffected by the organic matter amendments. Results suggest that the addition of organic matter may lead to increases in arsenic bioaccessibility, which warrants caution in the evaluation of risks associated with redevelopment of arsenic-contaminated land.  相似文献   
100.
In Memoriam     
ABSTRACT

A feasibility study of polychlorinated biphenyl (PCB) removal from contaminated soils using microwave-generated steam (MGS) was performed. Initial experimental results show that MGS effectively removed PCBs from contaminated soil with an overall removal efficiency of greater than 98% at a steam-to-soil mass ratio of 3:1. Removal efficiency was found to be dependent upon the amount of steam employed, expressed as a mass ratio of steam applied to soil mass. Evaporation was identified as a major mechanism in removing PCBs from the soil. Rapid expansion and evaporation of pore water by microwave dielectric heating accelerated evaporation rates of PCB molecules. Increased solubility of PCBs into the heated aqueous phase is also hypothesized. Together these effects increase mass-transfer rates, thus enhancing removal of PCBs from the soil.  相似文献   
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