Investigation of fusion welded butt joints in structural steels

In the present paper research work is presented combining material related research, weld fabrication related research and research in the field of numerical analysis of welded joint performance. Elements belonging to this extensive combination are mechanical testing, fracture mechanics testing of small scale and full thickness specimens, component testing including engineering defect assessment and numerical modelling using finite element method. Examples are given for each of the above mentioned elements.     

A new method of measuring and presenting the membrane fouling potential

The silt density index (SDI) and modified fouling index (MFI) characterisation methods are well known for the evaluation of membrane fouling potential of dispersed particulate matter (suspended solids, colloids) in a feed. The SDI and MFI methods, however, reduce the overall and very complex fouling phenomena into a one number value, on which the interpretation of the fouling potential of the feed is based. Considering such a one number characteristic, a significant amount of information from the fouling measurement (data) is lost. In this paper a concept is introduced in order to preserve such information and supplement the existing indexes. The proposed method measures, processes and presents data in a specific format. To illustrate the concept, some results are shown from measurements on three types of feed. Future systematic research will also include the measurement on some model feeds with, for example, well characterised dispersions for comparison purposes. However, based on the contents of this paper, a discussion on the method could be initiated.     

Motionless mixers for the design of multitubular polymerization reactors

Experimental investigations of thermal bulk polymerization of styrene in pilot plants of different sizes have been performed. Each pilot plant is composed of a tubular recycle reactor, connected in series with a tubular reactor, both completely filled with Sulzer motionless mixers. Kinetic, reactor and viscosity models have been verified in a wide range of styrene conversions (up to 96%) temperatures (up to 210 °C) and polystyrene molar masses (up to 360 000). Scale-up studies were carried out which confirmed that multitubular reactors of special design can be applied for industrial polymerization process.     

Reprocessing of thermally oxidized aluminum arsenide (AlAs) in epitaxial multilayers without delamination

Annealing or processing of AlAs that has been subjected to a wet thermal oxidation process can result in severe delamination of material at the oxidation front. This paper reports a procedure for preventing this delamination and presents a possible cause for the delamination.     

Effect of Castration and hormonal supplementation on cholesterol cholelithiasis in the male hamster

This study examined the effect of castration and dietary hormonal supplementation on cholesterol cholelithiasis in male hamsters. Animals fed a standard lithogenic diet developed cholesterol gallstones (17%) after 6 wk, while castrated hamsters did not form any stones. Addition of a synthetic androgen, methyltestosterone, to the lithogenic diet induced cholelithiasis in castrated animals (50%). The biles of normal and castrated-hormone supplemented hamsters had cholesterol saturation indices of 1.0 and 1.1, respectively, while the bile of the castrated animals remained unsaturated (0.6). The ratio of cholic acid/chenodeoxycholic acid in bile increased after castration, but returned to normal levels following hormonal supplementation. Biliary cholesterol carriers were separated by ultracentrifugation. Animals in the stone-forming groups (normal and castrated-hormone treated) had a significant proportion of their biliary cholesterol in vesicles (44 and 46%, respectively); castrated hamsters had less cholesterol in vesicle form (9%). The molar ratio of cholesterol/phospholipid in vesicles was reduced after castration (0.93 vs. 0.42) and increased by hormonal supplementation (1.89). In conclusion, when compared to normal male hamsters fed a standard lithogenic diet, castration reduced the cholesterol saturation of bile, lowered the vesicular/micellar ratio in bile, and inhibited cholesterol cholelithiasis. Dietary androgen supplementation increased the lithogenicity of bile, resulting in stone formation in castrated animals.     

Zum Magnesiumabbrand in Eisenschmelzen

Erläuterung der Problematik des Magnesiumabbrands beim Bereithalten magnesiumbehandelter Gußeisen-Schmelzen. Diskussion von Messungen des zeitlichen Verlaufs des Magnesiumabbrandes. Theoretische Überlegungen zur Deutung der Messungen durch Verdampfung, geschwindigkeitsbestimmenden Transport zur Tiegelwand oder einen geschwindigkeitsbestimmenden Vorgang 1. Ordnung in der Tiegelwand. Schlußfolgerungen für die Praxis.     

Zur Wirkung von Pimaricin auf Schimmelpilze und deren Aflatoxinbildung bei K?sen

Zusammenfassung Voraussetzung für die Anwendbarkeit des Pimaricins ist dessen Hitzestabilität (bis ungefähr 80° C) und die geringe Eindringtiefe (knapp 2,6 mm), so daß es für die konservierende Wirkung auf der Oberfläche der Käse für längere Zeit zur Verfügung steht. An 13 verschiedenen aflatoxinbildenden Schimmelpilzen wurde die Hemmung auf die Mycelentwicklung und damit auf die Aflatoxinbildung festgestellt, wobei die einzelnen Schimmelpilze unterschiedlich gehemmt werden. Bei Käsen war die Wirkung nicht eindeutig, da die native Oberfläche, der Käse (Rinde) nach Pimaricinbehandlung 8 Wochen vor dem Verschimmeln geschützt blieb, während daraus hergestellte Scheiben, in Pimaricinlösung getaucht, alsbald verschimmelten. Die Aflatoxinbildung selbst wird nur unterdrückt, wenn auch das Wachstum der Schimmelpilze unterbunden wird. Die Käse müssen daher möglichst frühzeitig behandelt werden, ehe es zu einer stärkeren Entwicklung der Schimmelpilze kommt. Die Aflatoxinproduktion setzt zwar erst bei einer nicht vollständigen Unterdrückung ein; es muß mit einer, wenn auch verminderten Aflatoxinbildung gerechnet werden.

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Effect of pimaricin on moulds and their aflatoxin formation in cheese

Summary The prior condition for the application of Pimaricin is its heat stability (up to 80° C) and the low penetration (around 2.6 mm), so that it is available for the effect on the cheese surface for a long period. With 13 different aflatoxin forming moulds, the inhibition on the mycel development and thereby on the aflatoxin formation was tested; the different strains were inhibited to various degrees. The effect on cheese was not definite, because the native cheese surface remained free of mould for 8 weeks after Pimaricin treatment, whereas cheese slices dipped into Pimaricin solution were covered with moulds very soon. The aflatoxin formation itself is only inhibited, if the growth of the moulds is inhibited. Therefore the cheeses have to be treated very early before strong growth of the moulds has started. The aflatoxin formation, however only starts at a certain growth period of the moulds, but at a not completed inhibition, a reduced aflatoxin formation has to be taken into consideration.

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Auszug aus: Erwin Zierer Zur Verhinderung der Aflatoxinbildung auf Käsen durch Pimaricin. Dissertation Techn. Universität München 1974.

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34. Mitt. Zur Aflatoxinbildung in Milch und Milchprodukten.