Bildung und Koaleszenz von Blasen und Tropfen

Formation and coalescence of bubbles and droplets. Generation and coalescence of bubbles and droplets are essential requirements for technical reactions and exchange processes. The paper deals with the dispersion of gases and liquids with the aid of single orifices and of sieve plates in liquids of various viscosities under gravity and centrifugal conditions and furthermore with the mechanical foam separation and with the coalescence of drops on inclined plates. The paper summarizes results from the literature as well as from the Sonderforschungsbereich (SFB) 153 at the Technical University of Munich.     

Struktur und eigenschaften von mehrphasenkunststoffen. Deformations- und bruchverhalten von polycarbonat/ABS-mischungen

PC/ABS-blends have gained growing importance as engineering plastics in numerous different application sectors by the realization of interesting property combinations. These blends are in use for a longer time, but the literature about the basic physical aspects is not very comprehensive. The here presented work examines the influence of sample composition on phase behavior, on yielding and notched impact behavior. Sample composition is changed by mixing different amounts of PC, SAN and grafted rubber (polybutadiene rubber grafted with SAN). The yielding and impact behavior is discussed in connection with the deformation mechanisms. A subsequent paper will deal with the deformation morphology of these blends.     

Nebenwirkungen von Salben- und Creme-Grundlagen und deren Konservierungsmitteln

Side-Effects of Ointment- and Creme-Bases and Their Preserving Agents Out of 130 patients with chronic venous insufficiency of the lower leg 27% were sensitive towards esters of hydroxybenzoic acid, 14.5% towards sorbic acid, and 12% towards Unguentum Lanette. A large number of patients were allergic towards hexachlorophene. It was difficult to explain the positive reaction towards cetyl pyridiniumchloride and hexyl resorcin. It is worth mentioning the positive tests which 16 patients showed towards a few recent emulsifiers, such as Span® 80, Span® 60 and Tween® 40. Emphasis is made on complete declaration of the ingredients of pharmaceutical and cosmetic preparations.     

Druckstandfestigkeit und Betriebseigenschaften von Doppelwellendichtungen

The strength and operating properties of wave‐ring gaskets are analyzed. A cylindrical shell of constant mean thickness is introduced to simulate the gasket. It is assumed that the shell is simply supported at the inner surface of the seat. The influence of certain geometric, material and assembly parameters on the strength and leak‐tightness of the closure is investigated. The results are illustrated by a numerical example. For the assumed material of the gasket and several fixed data the other parameters of the closure are examined. The region of admissible solutions for the gasket parameters such as dimensions, applied assembly clearance and pressure is determined.     

Erfassung und Vermarktung von Schlachttierfetten

Marketing of Animal Fats. A great decrease in the use of animal fats for human nutrition has occurred since many years. Therefore other markets had to be found, which led to large volume of export. Domestic use of animal fats is predominantly for technical purposes. Consequently, no new economical methods were developed for separating high- and low-melting fractions. In the field of animal nutrition, the prejudices are disappearing since several years, and increasing amounts of animal fats are being used. Since animal fats are subjected to the same regulations that govern the treatment of meat, in Germany the refining of animal fats is fundamentally prohibited with few exceptions. In all other countries of European Community refining is permitted. Such discrepancies should be eliminated within the scope of harmonization efforts that are being made in the new food legislation of the European Community.     

Schmelzsalzwirkung von Na-Trimetaphosphat und Na-Tetrametaphosphat

Melting-Salt-Action of Na-Trimetaphosphate and Na-Tetrametaphosphate With Na-tetrametaphosphate as melting agent a homogeneous processed cheese was obtained, with Na-trimetaphosphate not. Hydrolysis of both cyclic phosphates under melting process conditions could be excluded. The differences in the melting behaviour are therefore interpreted by the different Ca-binding capacity which is low in Na-trimetaphosphate whereas Na-tetrametaphosphate has a figure within the range of the usual melting salts.     

Konstitution und Eigenschaften von Tensiden

Constitution and Properties of Surfactants From the information available in the literature and author's own investigations, general rules regarding the optimum structure of anionic and non-ionic surfactants are derived. Especially, linear, branched and cyclic hydrocarbon rests with hydrophilic groups in various positions are considered. Furthermore, the change in properties of surfactants by the introduction of etheric oxygen in the alkyl rest is demonstrated.     

Steuerung und Regelung von Dampfstrahlverdichtern

Operation and Control of Steam Ejectors On the basis of typical characteristics of steam ejectors the various possibilities for regulating the vacuum are discussed. It is shown that economy in steam consumption can be achieved by OZ-regulation, the savings being proportional to the fluctuating steam pressure and/or counter pressure.     

Synthese und Strukturermittlung von Sulfamoyl-guanidinen

Synthesis and Structure Elucidation of Sulfamoyl Guanidines A series of sulfamoyl guanidines 2a--hyphen;p and 4 was synthesized by addition of sulfurylchloride to dialkylcyanoamides and subsequent aminolysis of the N,N-dialkyl-N′-chlorosulfonyl-chloroformamidines with primary or secondary amines. Advantageously, the aminolysis can be performed with trimethylsilylamines as amine component by continuous withdrawing of the formed trimethylchlorosilane. Phase transfer catalyzed methylation led to a specific alkylation of the sulfamoyl group to form the 2-(aryl-methyl-sulfamoyl)-guanidines ( 5a--hyphen;5g, 5h ). All compounds were characterized by m.s.-, i.r.-, ¹H-n.m.r.- and ¹³C-n.m.r.-spectra. I.r. and ¹H-n.m.r. data show the existence of an intramolecular hydrogen bonding between the guanidine NH group and the SO₂ group.     

Synthese und charakterisierung von butadien-divinylbenzol-copolymeren

The copolymerization of butadiene with a technical divinylbenzene fraction was investigated to study the modification of cis-1,4 polybutadiene. Beside the Ziegler-Natta-catalyst nickeloctanoate/bortrifluoride/aluminiumtriethyl, another catalytic system consisting of nickeloctanoate/titaniumtetrachloride/aluminiumtriethyl was used, which allows to polymerize more divinylbenzene because of its higher activity toward vinylaromates. With the help of spectroscopical, pyrolysis-gaschromatographical and thermoanalytical methods one can obtain relations between glass-, crystallization- and melting temperature and the microstructure of the polymer. It can be shown that not only the divinylbenzene but also the trans-1,4- and the 1,2-vinyl units are statistically distributed in the polymer. By this, beside the pyrolysis-gaschromatography, particularly the differential scanning calorimetry is a useful tool to characterize the structure of partially crosslinked polymers obtained from polymerization of technical fractions.     

Konfiguration und Thermochromie von Benzoinhydrazon-Derivaten

Configuration and Thermochromic Properties of Benzoine Hydrazone Derivatives Z-Benzoine aroylhydrazones ( 2a – d ), E-benzoinephenylether phenylhydrazone ( 4 ) and E-benzoinephenylether p-chlorobenzoylhydrazone ( 5 ), respectively, are produced by acid-catalyzed reaction of benzoine and corresponding hydrazone derivatives. The configuration of these new compounds are proved by their u.v.-spectra and n.m.r.-spectra data. In comparison to the Z-isomers, the E-isomers possess a hypsochromically shifted electron transition. In the n.m.r.-spectra the Z-isomers can be detected by a downfield N–H-signal. Only the aroylhydrazones 2 have thermochromic properties in methanolic solutions, based on a geometrical E/Z-isomerization. The kinetic and thermodynamic data of this reaction agree with an inversion mechanism.