Zur Stabilität Stationärer Elektrischer Zweipolzustände

In connection with the work of U. F. Franck on the stability of electrode conditions equivalent circuits are presented for dipoles, the characteristics of which can be described by capacity and inductivity effects. Equations are derived for the variation of current and potential with time. From these equations conclusions can be made regarding the stability of the system and the occurrence of periodic phenomena. The latter are possible only if the dipole has duplicate storage properties.

The results obtained are checked with known electrical circuits and applied to experimental data taken from the literature pertaining to electrodes with surface layers.

Résumé

Analyse du rôle de la formation de dipoles stationnaires dans la stabilité des électordes, compte tenu des effets capacitifs et inductifs dûs au passage du courant. Dans les cas d'accumulation simple et d'accumulation double de ces dipoles, les lois de variation horaires de l'intensité et de la tension, après ouverture ou fermeture du circuit, peuvent être établies. Des critères de stabilité, dont on précise les modalités d'applications, en sont déduits.     

Anionen-grenzflächenaktive Stoffe aus Aminosäuren und Glycidäthern

Anionic Interfacially Active Agents from Amino Acids and Glycid Ethers After referring to the preparation of interfacially active agents by using amino carboxylic acids, especially sarkosine, experiments on the reaction of alkylene oxides as well as glycid ethers with amino carboxylic acids are described. Saturation concentrations, critical micelle concentrations and corresponding surface tensions (dyn/cm) of the aqueous solutions (0° d. H.) at 20° C are given for the adducts from glycine or sarkosine with octylene-1,2-oxide and n-octyl- or lauryl glycid ether.     

Fouling von Wärmeübertragungsflächen

Fouling of heat transfer surfaces . Fouling of heat transfer surfaces in industry causes considerable costs. Overcoming fouling is therefore essential for technical and economic reasons. Solution of the problems requires a better understanding of the physical, chemical and biological processes causing fouling. It is shown, that the prediction of the fouling behaviour of heat transfer equipment based on existing mathematical models is not jet satisfactory. This article presents a new physical model describing particulate and precipitation fouling based on the assumption of a deposition and a removal process. Experiments to prove the results of the theoretical considerations were carried out using an aqueous CaSO₄ solution. The test unit which is also suitable for in-situ measurements is described in detail. Measured and predicted asymptotic fouling factors agree with acceptable accuracy.