Variation sources

Chemical considered Media considered Spatial variation Source code availability Model availability Dynamic or steady-state Availability for sensitivity and uncertainty analyses... 

Mann U. and Stein R. (1997) Organic facies variations, source rock potential, and sea level changes in Cretaceous black shales of the Quebrada Ocal, upper Magdalena Valley, Columbia. Am. Assoc. Petrol. Geol. Bull. 81(4), 556-576. 

High-throughput experimentation has been applied for the evaluation of the responses of different-size CdSe nanocrystals incorporated in a variety of rationally selected polymer matrices. Automation of these experiments not only speeds up the screening process of candidate sensing materials, but also importantly reduces or eliminates variation sources that otherwise affect response of the sensing materials if measurements are done manually. 

Scheme 5 Decision tree for the disposition of particle size variation. Source Courtesy of Pharmquest Corporation, Mountain View, California, U.S.A.

Massoia bark essential oil, raw material to make Massoia lactone, which suffered from considerable quality variations. Sourcing a reliable supplier required numerous analyses and laboratory distillations of different barks. 

The ILD thickness variation sources can be categorized into wafer-level, die-level, die and wafer interaction, and residual terms. The wafer-level variation is often caused by process perturbation and drifts in equipment and consumables, and is relatively invariant of pattern density and other layout effects. On the other hand, the die-level variation is attributed to... 

New combinatorial schemes are needed where various reaction variables can be altered simultaneously and where important cooperative effects can be carefully probed to provide better understanding of variation sources. New performance models must be developed that can relate intrinsic and performance properties and can provide transfer functions of scalability of performance of chemical reactors from nano- to macroscale. Advances in... 

FIGURE 4 Flow control creates virtual surfaces to provide classic nozzle functionality without mechanical variation. Source 2002 by Lockheed Martin. Published with permission. 

Simulation results comparing conventional and proposed models to experimental results with parameter variations. Source Kim, S. H., W. Choi, K. B. Lee et al. 2011. IEEE Transactions on... 

Often a number of physical, chemical, and biological processes have to be considered as they may markedly affect water quality and its spatial variations. Sources of heterogeneity within a body of water that need careful consideration in selecting sampling sites are as follows ... 

A general rule for developing a calibration database is to include all the sources of variation that you expect to encounter during routine analysis. Often, two sources of variation are not well represented in the Product Library file (nomenclature used by NIR Systems). One is variation in temperature, both of the sample and of the instrument. Temperature affects OH bonding, causing a shift in the composite absorption peak for water. This shift is affected by starch content. The other source of variation is instrument differences that remain after instrament standardization. This is less important if several standardized instruments were used to scan samples for the Product Library. Variation sources such as these can be incorporated into the calibration after the database is developed by creating a repeatability (REP) file. A REP file contain spectra of one or more sealed samples scanned under different conditions. 

Antignac J-P, Cariou R, Maume D et al (2008) Exposure assessment of fetus and newborn to brominated flame retardants in France preliminary data. Mol Nutr Food Res 52 258-265 Asante KA, Adu-Kumi S, Nakahiro K et al (2011) Human exposure to PCBs, PBDEs and HBCDs in Ghana Temporal variation, sources of exposure and estimation of daily intakes by infants. Environ Int 37(5) 921-928... 

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