Color, defined

Elastic recovery Uniform coloration Defined splicing 1 5 PETP... 

HPLC is often reported to be the technique of best choice for the quantification of food colorants. According to European Directive 94/36/EC, the quantities of synthetic colorants to be added to foods are restricted and thus reliable methods for their quantification must be established. Approved colorants, defined by E-coded numbers (Table 6.6.2), are permitted for non-alcoholic beverages, confectionery products, and even for caviar (dying fish roe). For example, a specific HPLC chromatographic method for the quantization of 14 synthetic food colorants belonging to azo dye, triphenyhnethane, or quinophthalone classes (E 102,104, 110, 122,123, 124, 127, 128, 129, 131, 132, 133, 142, 151) was reported to check their contents in caviar. ... 

Figure 8.6 shows the projection of 1346 compounds from Johnson Johnson on the VolSurf metabolic stability model. The projected compounds are color-coded according to their percentage experimental metabolic stability (%MS) the red color defines compounds with %MS > 95, while the blue color defines compounds with %MS < 40. The figure shows that the great majority of projected compounds with %MS > 95 are predicted to be of medium or high stability for the metabolic activity of the CYP3A4, while compounds with low %MS < 40 are predicted to be unstable. The presence of outliers may be explained by the fact that the experimental %MS of the test set compounds is obtained from the activity of all CYP family enzymes (2C9, 3A4, 2D6 etc.), while the model uses only 3A4 mediated information. 

The purity criteria specifications for colorants approved for use in Europe are laid down in European Directive 95/45/EC. Each colorant defined by an EEC number has a monograph listing the required... 

Table 1 also includes the values of the durability parameter, Vl/2, and the colorability, defined as the apparent molar extinction coefficient EapP = DB//[A], along with the thermal bleaching rate constants k and after the first and nth flash, respectively. It may be noted that k generally increases with the number of flashes. 

Munsell, A. H., Book of Color Defining, Explaining, and Illustrating the Fundamental Char-... 

Note that the usual vertex coloring is a fractional coloring defined by / I G) 0,1, where the maximal monochromatic independent sets map to 1, and all other sets map to 0. The weight of this fractional coloring is equal to the number of colors hence we have Xf(G) < x(G). 

Nearly every chemical manufacturiag operation requites the use of separation processes to recover and purify the desired product. In most circumstances, the efficiency of the separation process has a significant impact on both the quality and the cost of the product (1). Liquid-phase adsorption has long been used for the removal of contaminants present at low concentrations in process streams. In most cases, the objective is to remove a specific feed component alternatively, the contaminants are not well defined, and the objective is the improvement of feed quality defined by color, taste, odor, and storage stability (2-5) (see Wastes, industrial Water, industrial watertreati nt). 

Most hydrocarbon resins are composed of a mixture of monomers and are rather difficult to hiUy characterize on a molecular level. The characteristics of resins are typically defined by physical properties such as softening point, color, molecular weight, melt viscosity, and solubiHty parameter. These properties predict performance characteristics and are essential in designing resins for specific appHcations. Actual characterization techniques used to define the broad molecular properties of hydrocarbon resins are Fourier transform infrared spectroscopy (ftir), nuclear magnetic resonance spectroscopy (nmr), and differential scanning calorimetry (dsc). 

This same experimental approach can be used to determine the appHcabiUty of the aDAS—AP to a competitive assay for DAS. As shown in Eigure 6, increasing amounts of free DAS were used to define the 50% inhibition level (ID q) of DAS for binding of two aDAS—AP conjugates to immobilized DAS. This approach was also used to determine the sensitivity of an EIA, as well as the specificity of the assay, as shown in Table 2. Increasing amounts of trichothecene mycotoxins closely related to DAS were added to microtiter plate wells containing a constant amount of prereacted DAS—aDAS—AP. After 30 min, excess toxin and any free toxin—aDAS—AP were washed out, and substrate was added. Quantification of the color produced was directly related to the abihty of the added toxin to displace aDAS—AP from the immobilized DAS, which is an indication that the aDAS also has an avidity for that toxin. 

Fig. 6. A portion of the CIE color diagram where X and Y define the color. The shaded area shows the range of color of fluorescent lamps using calcium...

ASTM D883 defines a filler as "...a relatively inert material added to a plastic to modify its strength, permanence, working properties, or other quaHties or to lower costs." EiHers (qv) that modify the properties and characteristics of epoxies are employed in epoxy resins for a variety of reasons. Then principal functions are to control viscosity, reduce shrinkage and the coefficient of thermal expansion, effect a cost reduction, and color the epoxy resins. 

Olfactory receptors have been a subject of great interest (9). Much that has been postulated was done by analogy to the sense of sight in which there are a limited number of receptor types and, as a consequence, only three primary colors. Thus attempts have been made to recognize primary odors that can combine to produce all of the odors that can be perceived. Evidence for this includes rough correlations of odors with chemical stmctural types and the existence in some individuals having specific anosmias. Cross-adaptation studies, in which exposure to one odorant temporarily reduces the perception of a chemically related one, also fit into this hypothetical framework. Implicit in this theory is the idea that there is a small number of well-defined odor receptors, so that eventually the shape and charge distribution of a specific receptor can be learned and the kinds of molecular stmctures for a specified odor can be deduced. 

Experienced color matchers can achieve a good color match by trial and error without using any instmmentation. In some cases, however, this technique can be a lengthy process, and should the desired match be outside the color space defined by the available color standards, the technician might spend too much time just to determine that the match is not possible. To get the most cost-effective match using a low metamerism in the shortest possible time, the use of a computet color matching system is preferable. 

Lightfastness is measured by exposing pigmented film to an artificial or natural, eg, Florida exposure, light for a predetermined time. It is a relative term where the color of a sample exposed to a known light source is compared to its original color values. To make it meaningful, aH conditions of the exposure have to be weH defined. 

Dyes, on the other hand, ate colored substances which ate soluble or go into solution during the appHcation process and impart color by selective absorption of light. In contrast to dyes, whose coloristic properties ate almost exclusively defined by their chemical stmcture, the properties of pigments also depend on the physical characteristics of its particles. 

Blt-M ppedImages. A bit map is a grid pattern composed of tiny cells or picture elements called pixels. Each pixel has two attributes a location and a value or set of values. Location is defined as the address of the cell in a Cartesian, ie, x andjy coordinate, system. Value is defined as the color of the pixel in a specified color system. Geometric quaUties of images are a function of the location attribute, ie, the finer the grid pattern, the more precisely can the geometric quaUties be controlled. Color quaUties are a function of the value attribute, ie, the more bytes of computer memory assigned to describe each pixel, the more precisely can the color quaUties be controlled. 

There are several systems that define the quality and uniformity of natural mbber. One system of grading natural mbber is based on form and visual observation of color and cleanliness. This is known as the International Natural Rubber Specification. The principal types and grades are as follows. There are five other types of mbber classified by this system and many other grades not Hsted here. 

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