Color loss calculation

Absorbance was measured at 25 nm intervals from 325 nm to 500 nm. These values were converted to absorptivity (L g-1 cm-1) and the area under the curve was integrated from 350 nm to 500 nm using software by PolyMath Control Data ( 1984). This value was compared to corresponding values obtained with the starting material (lignin or HPL), and the color loss was calculated from... 

Similar calculations were done using seven individual wavelengths between 350 and 500 nm (i.e., at 25 nm intervals) and, using the sum of the absorp-tivities at the 7 wavelengths, color loss was computed from... 

Pipet a 10-mL sample into a 100-mL cassia flask fitted with a stopper, and add 50 mL of a freshly prepared 30 in 100 solution of sodium sulfite. Add 2 drops of phenolphthalein TS, and neutralize with 50% (by volume) acetic acid solution. Heat the mixture in a boiling water bath, and shake the flask repeatedly, neutralizing the mixture from time to time by the addition of a few drops of the 50% acetic acid solution, stoppering the flask to prevent loss of volatile material. After no coloration appears upon the addition of a few more drops of phenolphthalein TS and heating for 15 min, cool to room temperature. When the liquids have separated completely, add sufficient sodium sulfite solution to raise the lower level of the oily layer within the graduated portion of the neck of the flask. Calculate the percentage, by volume, of the aldehyde or ketone by the equation... 

Fig. 3 Heat generated and removed at the inlet of a monolith combustor vs. temperature, calculated from Eqs. (3) and (4) for the conditions presented in Table 1. The straight lines represent the heat transfer curves in the absence of radiation losses. When the inlet gas temperature is 280 C, Eq. (5) is satisfied for three values of 297 C, 371 C, and 1326 C. As the temperature of the inlet gas is increased, the two lower intersection points approach each other and eventually both points merge at = 335 C when the inlet gas temperature is 292°C. This is referred to as the catalytic ignition or light-off temperature. A further increase in the inlet gas temperature results in a situation where there is only one intersection point. (View this art in color at www.dekker.com.)...

The determination of density (specific gravity) (ASTM D-287, ASTM D-891, ASTM D-941,ASTM D-1217, ASTM D-1298,ASTM D-1555, ASTM D-1657, ASTM D-2935, ASTM D-4052, ASTM D-5002, IP 160, IP 235, IP 365) provides a check on the uniformity of the gasoline, and it permits calculation of the weight per gallon. The temperature at which the determination is carried out and for which the calculations are to be made should also be known (ASTM D-1086). However, the methods are subject to vapor pressure constraints and are used with appropriate precautions to prevent vapor loss during sample handling and density measurement. In addition, some test methods should not be appUed if the samples are so dark in color that the absence of air bubbles in the sample cell cannot be established with certainty. The presence of such bubbles can have serious consequences for the reUabiUty of the test data. 

---