Visual comparison

Many one-, two-, and three-dimensional systems have been developed over the years to order colors ia a systematic way and provide specimen colors for visual comparison. Coordination has now been achieved with computet programs between essentially all of these systems and the CIE systems described below and conversions can easily be made between them. 

In this work hybrid method is suggested to determine cationic surfactants in water. It is based on preconcentration of cationic surfactants in the some of ion associates with acidic dyes on the paper filter and measurement of color intensity by solid-phase specdophotomenic method or visual comparison. 

Much trade literature is of a high standard, particularly that of suppliers of the so-called engineering polymers . In many cases these manufacturers supply a range of such polymer types and they provide much useful comparative material. This may be in the form of descriptive material and tables of numerical data. Suitable choice of graphs and other diagrams can often give the reader a more immediately absorbed visual comparison. 

Colour (R) Legislation and controls Visual comparison ASTM methods... 

Ringelmann chart A method for the visual comparison of smoke from a chimney. The estimation is made by the comparison of the shade of smoke against shade cards. 

Light is measured in several ways. Until about 1960, most light measurements were obtained by visual comparison. A standard light source of known, but adjustable, brightness was compared by a trained... 

The US military specification (Ref 2) lists the following requirements for PIB (1) stability against depolymerization at 125°F (2) color -shall not be darker than a soln of Q.008g/ of K2Cr207/w by visual comparison and (3) chemical properties as shown in Table 1... 

After extraction of the neutral oil from the AOS sample, the neutral oil is made up volumetrically to at least a 10% solution in hexane. Of this solution 4 pi is spotted onto a silica gel TLC plate, together with terminal 5-sultone standard in the range 0.4-4 pg (equivalent to 0.1-1% sultone in the neutral oil). It is twice developed in a chamber saturated with 2-propyl ether. The solvent is completely evaporated and the spots visualized by vapor phase sulfuric acid charring using the technique described by Martin and Allen [139]. Humidity is not critical (10-30% is optimum) and activation of the plates has not been found necessary, but it might be required under conditions of high humidity. The level of sultone can be estimated by visual comparison with the standards or by the use of a densitomer. 

Below are the MATLAB statements that we may use for visual comparison of exponential decay with different time constants. In rough engineering calculations, a pole may already exhibit acceptable dominant behavior if other time constants are 1/3 or less. 

Methods for the instrumental measurement of whiteness are well established but visual comparison remains important, even in well-equipped laboratories. Some degree of quantification is achieved by the method of paired comparisons, in which a panel of observers is presented with pairs of FBA-treated samples and asked to decide, without undue delay, which is the brighter. The total of positive scores can be used as a measure of whiteness and the results presented graphically as shown in Figure 11.7. Although time-... 

Finally, both samples were analyzed using ATR-FTIR spectroscopy. The Si ATR crystal was brought into contact with the sample, and spectra recorded. Figure 51 compares the spectra. Based on the excellent match factor between the spectra of the two samples (99.8%) and visual comparison of these two spectra,... 

As a final test for comparing and contrasting mass spectra, an experienced and cautious investigator will always make a visual comparison. If there are a large number of data files, however, this process is tedious and time-consuming. Therefore, the new macros described below may be used to streamline the decisions about which putative peak matches require visual inspection of the actual mass spectra. 

Within 30min (the plate turns grey in strong light) any chlorinated paraffin in the sample is estimated by visual comparison between the sample and standard spot intensities. 

Calculations Calculate the content of cetylalcohol and of stearyl alcohol from the chromatogram thus obtained with solution (1) by normalization. Identify the peaks by visual comparison with the chromatograms obtained with solutions (2) and (3) respectively. 

Note For a rapid estimation of the isotopic patterns of chlorine and bromine the approximate isotope ratios Cl/ Cl = 3 1 and Br/ Br =1 1 yield good results. Visual comparison to calculated patterns is also well suited (Fig. 3.3). 

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