Analysis of transient and steady-state processes in the series (resonant)inverter

This paper deals with analysis of the transient and steady-state processes in series (resonant) inverters. Sets of differential and difference equations governing the transient and steady state processes are obtained and solved. The solution is found in closed analytical form. Theoretical and experimental results, both for transient and steady-state conditions, are compared and satisfactory agreement shown.     

Some Volatile Components of Vitis Vinifera Variety White Riesling. 2. Organic Acids Extracted from Wine

SUMMARY— The acids of a table wine from Vitis vinifera var. White Riesling were recovered by basic extraction from a methylene chloride extract of the wine. The acids were identified by gas chromatographic retention times and by infrared spectroscopy, in most cases both on the free acids and on the methyl, ethyl or hexyl esters. The major acids identified in the wine are: acetic, n-butyric, n-caproic, n-caprylic, n-capric, 9-decenoic, succinic, and ethyl acid succinate. Acids present in smaller amounts are: formic, propionic, isobutyric, 2-methylbutyric, isovaleric, lactic, 2-hydroxyisocaproic, n-pelargonic, and malic.     

Percutaneous absorption of urea

The effect of several variables on the in vitro permeation of urea through hairless mouse skin has been studied in order to determine the causes of an increasing permeability phenomenon found in studies with a range of hydrophilic compounds.
The permeation of urea increased for a period of approximately 100 h after which a steady state permeation pattern was observed for approximately 25 h. Urea did not effect its own permeation in concentrations between 0.01 M and 1.67 M, and the same pattern of increasing permeation was followed in the presence of ( N -morpholine)propanesulphonic acid and tris(hydroxyme)amino-methane buffers, as in the presence of normal saline. Urea did not affect the permeation of tritiated water. Methanol and water exhibited the same pattern of increasing permeation as urea.
The continuously increasing permeation rate of urea up to 100 h is believed to be due to penetration and extensive association of water with the components of the stratum corneum, altering the ultra-structure of the stratum corneum and leading to the formation of large and extensive hydrophilic diffusion channels which do not exist in fresh, untreated skin. These presumed channels open the stratum corneum to facile permeation of highly polar substances such as urea. The physical events leading up to the ultra structural changes within the tissue at the microscopic level remain obscure and are the subject of ongoing research.
L'absorption percutanée de l'urée     

Some Volatile Components of Vitis Vinifera Variety White Riesling.

SUMMARY— Volatile components of the grape Vitis vinifera var. White Riesling were isolated by reduced pressure steam distillation followed by solvent extraction and fractionation by gas-liquid chromatography. Individual components were identified by a combination of the techniques of functional group analysis, gas-chromatographic relative retention times, and infrared spectroscopy. Major components are: ethanol, isobutanol, 2.methylbutanol, 3-methylbutanol, 2-hexenal, n-hexanol, trans-2-hexen-1-01, and 2.Dhenethanol. Alcohols oresent in relatively smaller amounts are: methanol, n-butanol, n-pen-tanol, n-heptanol, linaloöl, n-octanol, n-decanol, and benzyl alcohol. Acids constitute only a small part of the total volatiles of White Riesling, the maior acids being: acetic, n-caproic, 2-hexenoic, n-caprylic, n-pelargonic, and n-capric. Acids present in trace amounts are: propionic, isobutyric, n-butyric, 2-methylbutyric, isovaleric, isocaproic, n-heptanoic, n-undecanoic, succinic, and ethyl acid succinate. The only esters detected were trace quantities of ethyl acetate and isoamyl acetate.     

Some Volatile Components of Vitis Vinifera Variety White Riesling. 3. Neutral Components Extracted from Wine

SUMMARY— The neutral components of a table wine made from Vitis Vigzifern variety White Riesling were isolated by methylene chloride extraction. Free acids were removed by basic extraction leaving the neutrals in the methylene chloride solution. Individual components were separated by preparative scale gas chromatography and identification was accomplished through comparisons of relative retention times of knowns and unknowns on several different gas chromatographic columns and by infrared spectroscopy. The neutral essence consisted principally of alcohols; the maior ones: ethanol, n-propanol, isobutanol, 2-methylbutanol, 3-methyl butanol, n-hexanol, levo-2,3-butanediol, and 2-phenethanol. Present in smaller amounts were: 3-methylpentanol, 4-methyl-pentanol, meso-2,3-butanediol and linalool. The second most common class of substances in the essence was esters; the major ones: ethyl acetate, isoamyl acetate, ethyl n-caproate, ethyl n-caprylate, n-hexyl acetate, 1,3-propanediol monoacetate, and 2-phenethyl acetate. Present in smaller amounts were: n-propyl acetate, isobutyl acetate, 2-methylbutyl acetate, levo-2,3-butanediol monoacetate, ethyl lactate, ethyl 3-hy-droxybutyrate, ethyl 2.hydroxyisocaproate, ethyl n-caprate, ethyl 9.decenoate, diethyl succinate, diethyl malate, dimethyl phthalate, and diethyl phthalate. Components of functionality other than alcohols or esters were: y-butyrolactone, N-ethylacetamide, diethyl acetal, and acetaldehyde.