Factors affecting laboratory evaluation

Ernst, W. 1979. Factors affecting the evaluation of chemicals in laboratory experiments using marine organisms. Ecotoxicol. Environ. Saf. 3 90.98. 

Most of the available information on settling concerns small laboratory units. In practice, settling basins and thickeners are of large size and are kept in continuous operation. Comings (1940) presented an excellent practical discussion of these and other factors affecting their operation. However, it remained for Kammermeyer (1941) to evaluate the importance of these factors quantitatively. 

EPA. 1996. Sources and factors affecting indoor emission from engineered wood products Summary and evaluation of current literature. Research Triangle Park, NC U.S. Environmental Protection Agency, National Risk Management Research Laboratory, Office of Research and Development. PB96-183876, EPA-600/R-96-067. 

It is evident that attention paid in the laboratory to the factors affecting particle size distribution will save on capital investments made for separation equipment and downstream process equipment. Specific cake resistance (a) can be determined in the laboratory over the life of a batch, to evaluate if time in the vessel and surrounding piping system is degrading the product s particle size to the point it impedes filtration, washing and subsequent drying. 

Kinetic studies may be used to evaluate the factors affecting the efficiency of removing trace organic pesticides from water by chemical oxidants. The rates of oxidative reactions and the optimum conditions under which the reactions occur are determined in the laboratory before applying them to pilot plant or field studies. Kinetic data also compares the efficiencies of different oxidants with the economy of different treatment processes. 

In SSF, several parameters such as particle size, moisture content, incubation time, initial pH, and the amount of nitrogen sources have been shown to be important factors affecting the fungal growth and chitosan production (Nwe and Stevens 2004). An important aspect related to the production of chitosan in SSF has been use of different kinds of laboratory model bioreactors including Erlenmeyer flasks, rotary drum bioreactors, roux bottles, trays, and glass columns to evaluate... 

Durihg recent years a considerable amount of re-.search has been undertaken to understand what in the makeup of a polymer affects the processability. In the late 1980s, the Rubber Manufacturers Association in the United States undertook a research project with the Department of Polymer Engineering at the University of Akron to evaluate the laboratory equipment available using specially made butadiene-acrylonitrile polymers with different acrylonitrile levels, molecular weights, and molecular weight distributions. The results from the study confirmed that, from the processing variables viewpoint, the major factors are frequency (shear rate), temperature (temperature), and deformation (strain). 

Table 20.4 presents the partition and transformation processes known to occur in the near-surface environment along with the special factors that should be considered when evaluating data in the context of the deep-well environment. Geochemical processes affecting hazardous wastes in deep-well environments have been studied much less than those occurring in near-surface environments (such as soils and shallow aquifers). Consequently, laboratory data and field studies for a particular substance may be available for near-surface conditions, but not for deep-well conditions. 

In addition to the retest values associated with the OOS sample, samples from lots or batches analyzed along with the aberrant sample (i.e., within the same analytical run) should also be evaluated since they may have been affected by the same errant factor that produced the OOS result. The fact that an accompanying sample passed specification while another failed may be only a result of serendipity. One practice employed by several industrial laboratories is to retest samples that bracketed (surrounded) the OOS sample in the original analytical run. Although the initial results from these... 

An atlas of NMR spectra (the OCAD version 7 from April 2004 contained 1391 NMR spectra) of the OCAD has been compiled with the assistance of dedicated laboratories worldwide. The efforts of the laboratories and the OPCW have yielded a useful high-quality NMR spectral database. The only factor limiting its usefulness could be the difference of the instruments (in magnetic field strength and resonance frequency) that were used, because the resonance frequency may affect the spectrum appearance, in particular, in NMR. However, this is not considered to be a serious problem because many of the spectra were recorded on 300-400-MHz instruments whose spectra do not differ much from those recorded at 200 or 500 MHz. The difference between the two extremes may be larger. The OPCW requires that all spectra to be included in the OCAD be evaluated and validated. 

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