Dielectric properties (dielectric constant ~-' and dielectric loss E') were compared to conventional methods of analysis (viscosity, refractive index, iodine value, peroxide value and free fatty adds) for evaluating the frying quality of a blend of cottonseed and sunflower oils. The apparent relaxation time, T, the activation energy H and the entropy change S for dielectric relAxAtion of the heated oil samples were calculated. Results indicate that dielectric constant and dielectric loss are useful tools for predicting deterioration occurring during heating of the oil.
By the application of a modified form of Onsager's equation to dilute solutions of glycerol in isopropyl alcohol and isobutyl alcohol, and conversely to dilute solutions of each of the latter two alcohols in glycerol, it is found that the apparent solution moments of these alcohols, at the condition of infinite dilution, are 2.68, 1.61, and 1.66 D respectively over the temperature range 30 to 50 OC.
Unbleached kraft bagasse pulp was subjected to beating in Jokro beater for different time intervals. Beating caused minor chemical changes mainly a slight increase of DP, crystallinity and resistivity to acid hydrolysis. Fiber fractionation by weight and by number indicated that the most pronounced action of beating is the cutting of the long fibers and fibers of medium length causing an increase in the quantity of short fibers. The tear factor started to decrease very early in the beating cycle, while the other mechanical properties increased by beating but with different rates.Bewertung von ägyptischem ungebleichten Bagasse-Kraft-Zellstoff. Teil I: Wirkung der Mahlung auf die chemischen und mechanischen Eigenschaften
ZusammenfassungUngebleichter Bagasse-Kraft-Zellstoff wurde in der Jokro-Mühle verschieden lange gemahlen. Durch die Mahlung werden die chemischen Eigenschaften kaum verändert, jedoch steigt der DP leicht an, ebenso die Kristallinität und die Resistenz gegen Säurehydrolyse. Gewichtsmäßige und zahlenmäßige Faserfraktionierung zeigen, daß die langen und mittellangen Fasern gekürzt werden, so daß die kurzen Fasern zunehmen. Schon im frühen Stadium der Mahlung nimmt die Fortreißfestigkeit ab, während die anderen mechanischen Eigenschaften sich durch den Mahlprozeß verbessern.
IntroductionBeating refers to über Separation, über cutting and also fibrillation of fibers. The effect of beating is of fundamental importance in determining the paper making qualities of a given pulp. Generally, beating is primarily a mechanical process resulting in physical changes in fibrous structure and colloidal nature of the pulp (Casey 1960).Gurr an et al. (1930) found that in the case of Sulfate pulp, the i % alkali solubility was increased f rom 4.5 to 5.8% on beating for 6 hours, but this, too they attributed to a slight increase in reactive surface. Kress and Bialkowsky (1931) found that alpha cellulose content, copper number, and alkali solubility all remain practically constant during the beating of an unbleached Mitscherlich sulfite pulp, whereas the cupperammonium viscosity decreases and the ease of hydrolysis of the fibers in acid increases. The increase in hydrolysis number and decrease in cupperammonium viscosity are probably physical rather than chemical effect resulting from an increase in surface activity.Goldsmith and Higgins (1954) studied the effect of fiber length on the mechanical properties of paper. A well beaten eucalypt kraft pulp was fractionated to 4 fractions. A rapid fall of folding endurance was noted in going from the finest to the coarsest fraction. The fine fraction evidently act äs bonding materials. Al-
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