water. , Thus certain gases, such as carbon dioxide, hydrogen, and hydrogen sulfide, tend to saturate the surface layers of the water fairly readily, and the layers so formed are of considerable permanency and not easily dislodged. On the other hand, gases such as nitrous oxide, nitric oxide, and chlorine show no tendency to form such saturated surface layers and are absorbed at a correspondingly higher rate.Since in most cases the effect of dissolved gas on the density of the water is to increase it, we may form a picture of the process by assuming that the first action is to form a saturated layer which is heavier than the rest of the liquid and tends to sink. At the same time the surface tension and the viscosity of the liquid tend to maintain the surface in its original condition. Whether the layer will sink and at what rate is then determined by the relative magnitude of these opposing agencies, which also determine whether the layer will be stable or unstable-i. e., whether the rate of solution will be greatly affected by slight disturbances of the liquid or not.The effect of dissolved gas in the surface tension and viscosity of the liquid is of importance even when the liquid is used in a scrubbing tower, as it has been pointed out by Hurter6 and also by Donnan6 that these properties may affect the effective interface of the gas and liquid owing to their effect on the formation of drops, splashing, and the wetting of the packing material of the tower. The matter is therefore: of considerable importance and worthy of further study. DiscussionIn discussing the first halff'of Dr. Becker's paper, R. P. Russell pointed out the similarity between Dr. Becker's results with stirred solutions and the theory presented by Dr. Lewis. Since the atmospheric .gases are only slightly soluble, the absorption of these gases is determined by liquid diffusion. Although Dr. Becker had developed his equation with a different nomenclature and had finally expressed it in integrated form, the basic principle was the same in both treatments. In fact, the coefficient/, when multiplied by 60, was the same as Dr. Lewis' coefficient kLl the factor 60 being necessary to convert from minutes to hours.The results obtained when the liquid was free from agitation could not be interpreted so readily, since it was evident that stratification effects were pronounced. Such results could not be subject to the formula proposed by Dr. Lewis, which assumed uniformity of composition in the main bodies both of the liquid and of the gas. However, it was possible that the initial absorption rates tabulated by Dr. Becker would conform to the theory, provided the influence of stratification was unimportant at the start. Mr. Russell had therefore calculated absorption coefficients from these initial rates, assuming that the rate was controlled entirely by liquid film diffusion. He believed that it was permissible to neglect any gas film because Dr. Becker worked with pure gases.These calculations gave values of kL varying from 1.1 to 15-i. e., a 14-fold r...
Light fading of some typical sulfonated acid wool and direct cotton dyes has been assessed, visually against the blue standards, on cotton, wool, silk, and anodized aluminum, and spectrophotometrically in films of regenerated cellulose and gelatin, at various respective relative humidities of the surrounding atmosphere. Some tests were also made in which the films were exposed to light when sealed against entrance of air. The known, lower susceptibility of fading rate to relative humidity of dyes on wool compared with cotton is confirmed and shown to apply also to silk and gelatin. Fading of dyes on anodized aluminum, after sealing, is unaffected by any change in the humidity of the surrounding atmosphere. It is suggested that on cotton, increase in RH causes more rapid fading because of increased fiber swelling, which accelerates transport of oxygen to the excited dye molecule. The anodic film on aluminum does not swell and so is unaffected by change in RH. Though the swelling effect operates with proteins, it is less noticeable because fading thereon is only partly caused by oxidation; mainly it is due to reduction, hydrogen being abstracted from the substrate itself, and therefore fading is less dependent on oxygen transport into the fiber. This suggestion is consistent with the observation made in this work—that fading on cellulose is considerably retarded by completely sealing the dyed substrate against air, whereas fading on a typical protein (gelatin) is hardly affected at all.
The p-nitrophenol adsorption method has been used to determine the specific surface, and hence the particle size and aggregation number, of a high-lightfastness direct dye (C.I. Direct Green 26) in regenerated cellulose film. The particle size found at high concentrations is of the same order as that found for other dyes of this type, in cellulose film, by Weissbein and Coven, using electron microscopy. The aggregation number rises rapidly with rise in dye concentration in the film to a maximum of the order of 106 at shade depths above about two percent pure dye on film weight.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.