نتایج جستجو برای: particulate sample filters
تعداد نتایج: 475951 فیلتر نتایج به سال:
The insoluble particulate matter deposited on ice sheets provide key information to reconstruct past climate. low concentration of some matter, such as terrigenous particles and microfossils, challenges the efficiency recovery representativeness results. Here we present a new optimized method extract, quantify classify targeted matter. Particle rates particle distribution were investigated usin...
Epidemiologic reports by C.A. Pope III et. al. demonstrated that in the Utah Valley, closure of an open-hearth steel mill over the winter of 1987 was associated with reductions in respiratory disease and related hospital admissions in valley residents. To better examine the relationship between plant-associated changes in ambient particulate matter (PM) and respiratory health effects, we obtain...
BACKGROUND Cigarettes are being marketed with filters that differ in composition and design. The filters have different toxicant trapping efficiencies, and smoking stains reflect variations in smoking behavior. Presented herein are the results of a structured literature review that was done to identify cigarette filter-based assays that may serve as proxies for mouth-level exposure and assessin...
A recursive weighted median (RWM) filter structure admitting negative weights is introduced. Much like the sample median is analogous to the sample mean, the proposed class of RWM filters is analogous to the class of infinite impulse response (IIR) linear filters. RWM filters provide advantages over linear IIR filters, offering near perfect “stopband” characteristics and robustness against nois...
A new method for determination of pyrethroids, pyrethrins, and piperonyl butoxide (PBO) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was developed for surface water samples. The method is based on sampling 100 L of ambient surface water with a solid phase extraction (SPE) technique that uses both wound glass fiber filters for collecting the particulate-ass...
Background: The built environment of the International Space Station (ISS) is a highly specialized space in terms of both physical characteristics and habitation requirements. It is unique with respect to conditions of microgravity, exposure to space radiation, and increased carbon dioxide concentrations. Additionally, astronauts inhabit a large proportion of this environment. The microbial com...
Particulate organic matter for lipid analyses was collected from specific water depths by in situ filtration of large volumes (,1,000 l) of water through 292-mm diameter precombusted (at 450 8C) glass fibre filters (GFF; nominal pore size 0.7 mm) with in situ pumps. Because filtration through 0.7-mm pore-size filters could lead to an undersampling of anammox cells, the calculated ladderane lipi...
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