Review of hydrogenation

A brief review of hydrogenation as applied to hardening of vegetable oils, conversion of glycerides or other esters of fatty acids into alcohols of high molecular weights, reduction of carbon monoxide to hydrocarbons or to alcohols, and hydrogenolysis of petroleum. Some mention is made also of the types of catalysts as well as the operating conditions employed in each instance. In addition, a short outline of various methods for the commercial production of hydrogen, and also its purification, is included.     

Determination of air content in dry shortenings

A method of test is described for the determination of dry shortening air content. Liquid mediums are prepared which have identical specific gravity to that of the shortening which is under test. Simple calculation of specific gravity data gives the air content. A distinct advantage to the method lies in the fact that air content can be determined for any shortening sample size.     

Die Selbsterregung von Schwingungen

Zusammenfassung Das Problem der Selbsterregung von Schwingungen wird in vollster Allgemeinheit von der rechnerischen Seite in Angriff genommen. An Hand der Differentialgleichungen für die Rückkopplung und für den Induktionsgenerator wird eine bestimmte Klasse von Differentialgleichungen — die Hillsche — als für die Selbsterregung in Frage kommend abgegrenzt. Es wird an Hand der Arbeiten von A. Erdelyi ein Bericht über den Stand der mathematischen Theorie gegeben.Die anschauliche Ausdeutung der mathematischen Ergebnisse ergibt: Wesentlich für eine Selbsterregung ist eine Kompensation der DÄmpfung (Rückkopplung, Selbststeuerung, fallende Kennlinie). Die Kompensation erfolgt durch die Einwirkung der Schwankungen von charakteristischen Parametern des Kreises (L, R, C); die van der Polsche Theorie wird erweitert und modifiziert. Ist der Einflu\ der Schwankungen schwach, so erfolgt eine Modulation (Amplituden, Phasen-Frequenzmodulation). Ist der Einflu\ stark, so kann unter genau bestimmten UmstÄnden eine Mitnahme eintreten. Die Mitnahme wird von einer zusÄtzlichen Frequenzmodulation verzerrt. Der Resonanzfall der Mitnahme ist schlie\lich die Selbsterregung, für die die zusÄtzliche Frequenzmodulation verschwindet. Hat die Parameterschwankung starke Oberschwingungen, so kann eine Mitnahme oder Selbsterregung in diesen Oberwellen stattfinden.Der Kern der quantitativen Formulierung bildet ein StabilitÄtskriterium, welches Frequenzen und Amplitude der entstehenden Schwingung in ein festes VerhÄltnis setzt. Die StabilitÄt einer Schwingung kann genau errechnet werden.     

EFFECT OF GLASS COLOR ON SETTING RATES IN MANUFACTURE OF GLASS BOTTLES *

It has been observed in the manufacture of bottles of the same size and shape from various colored glasses, such as emerald green and amber and the so-called flint bottle glass, that higher machine speeds are usually obtained in the case of the colored glasses. A laboratory test has been devised to measure the cooling rates of several colored and colorless glasses throughout their respective working ranges, which gives results paralleling the speeds obtained in actual bottle manufacture.     

THE EFFECT OF DIFFERENT BODIES ON SOME WETTING AND FLOW CHARACTERISTICS OF GLAZES *

Variations in the fluid properties of glazes produced by different bodies were studied, and several methods for testing the wetting ability of the glazes were compared. An angle-of-contact method was found best for measuring the ability of glazes to wet bodies. It was found that different bodies had varying effects on the fluid properties of a glaze. The maturing temperatures of a glaze are not fixed for a given glaze but may vary as much as four cones on different bodies, if wetting ability is considered in determining this temperature.     

Changing trends in detergents

In the enormously large and varied field of cleaning agents, a review of the changing trends in the field once held chiefly by soaps. and a few chemicals, is of interest. The author has summarized the general theory and ways of preparing many of the new detergents and has indicated the direction of future research to provide many more products which will serve as agents along side of, or as substitutes for many of the old ones.