Cumulative sampling

Cumulative sampling A system in which the sample is accumulated over the time, either by being taken continuously or tor periods at regular intervals to a given single sample. Its composition is regarded as representative of the whole of its accumulation. 

The most common methods for trapping pesticide vapors from air use adsorbents. Common air sampling adsorbents include charcoal (derived from petroleum or coconut) and synthetic polymeric materials, such as cross-linked polystyrene and open-cell polyurethane foam. Charcoal has been used for the cumulative sampling of volatile... 

Lot Size or Batch Size Code Letter Sample Size Cumul. Sample Size Critical Defects AQL 0.0% Major Defects AQL 1.0% Minor Defects AQL 2.5% ... 

Notes Acc. = acceptance number Rej. = rejection number Cumul. = cumulative sample. 

Frommberger R. 1990. Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in cumulative samples of human milk from Baden-Wuerttemberg, FRG. Chemosphere 20 333-342. 

US Army (1996b). Cumulative Sample Analysis Data Report, HD Ton Container Survey Results. March... 

DOA NC-131 Project, planned stations over entire U.S. cumulative sampling and analysis for each ecological studies. 

Lot size Sample Sample size Cumulative sample size <— AQL (normal inspection) —> ... 

It is advisable to perform the sampling as a weight-dependent rather than as a time-dependent operation. In the former case the sampler is controlled direct by a belt weigher. The cumulative sample is homogenized in a special mixer after a certain quantity (tonnage) of material has been collected. With both methods suitable belt conveyors and automatic counting equipment are required. The samplers can be adjusted to take any desired quantity. 

Cumulative samples from automatic sampling stations may be affected by systematic errors. The only way to detect such errors is by taking random samples at the same time as the cumulative samples. The random samples are split, prepared... 

Air pollution sampling methods may be classified in three categories based on the temporal patterns of the sampling process automated continuous sampling, cumulative sampling, and grab sampling. 

Cumulative samplers can be used to greatest advantage in determination of spatial variations in pollutant concentration their low cost and small size relative to automated air monitoring devices makes it practical to deploy samplers at multiple locations simultaneously throughout a study area. Cumulative sampling is also the only feasible method currently available to make quantitative measurements of personal exposure to most air contaminants at typical ambient concentrations in the general urban environment. 

Spicer et al. (6) collected 16 consecutive 3-hour cumulative samples of VOCs, trace elements, and particle-bound organics on three different occasions over a period of four weeks at each of six sampling locations in different sections of Columbus, Ohio. The sampling sites included a downtown commercial location and several residential areas with varying proximity to major roads, highways, and business areas. Analysis of variance performed on the sampling results indicated that variability between sampling locations was... 

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