Verhalten des Stahles X 6 CrNi 18 11 unter kombinierter Kriech- und Wechselbeanspruchung bei 823 K

Experimentelle Untersuchung des Kriech- und Wechseldehnverhaltens des austenitischen Stahles X 6 CrNi 18 11 (Werkstoffnummer 1.4948) bei Beanspruchung durch Kriechen und Ermüden. Auswertung der Ergebnisse unter Anwendung der linearen Schadensregel. Vergleich mit Auslegungskriterien nach dem ASME BPVC.     

Monohydroperoxides of linoleic acid in endoplasmic lipids of rats exposed to tetrachloromethane

An accurate method for the quantitative determination of hydroperoxy and hydroxy fatty acids in liver microsomes is presented which involves the use of¹⁸O-labeled internal standards. The method is employed for the determination of hydroperoxides in rat liver microsomes after aerobic incubation with Fe²⁺/ADP and in microsomes from animals exposed to 75 mg tetrachloromethane/kg body weight. The amounts found after artificial microsomal “lipid peroxidation” are almost two orders of magnitude larger than those in microsomes from tetrachloromethaneexposed animals.     

Controlling Copper Conversion via Optical Spectroscopy

Using optical spectroscopy to study the metallurgical conditions in a cop-per converter, the critical end-point of the slag-blowing stage has been inves-tigated and a correlation established between the optical emission proper-ties of the converter flame and the Cu content of the white metal. Several practical implications for enhanced control of the converter process were also identified.     

Polystyrene-supported acid catalysis

The present state of polymer-supported acid catalysis is considered. Models describing the catalytic action of gel-like and macroporous resin catalysts are presented. By chemical modification of poly (styrene-co-divinylbenzene) matrices, e.g. different ways of sulphonation, nitration, chlorination, fluorination and sulphoalkylation, the activity/selectivity and thermal stability of sulphonic acid resin catalysts can be improved. The synthesis of polymer-supported Lewis acids is described. By comparison to AlCl₃ higher catalytic activities are obtained with the use of AlBr₃.     

Characterization of the acidity of faujasite- and pentasil-zeolites by calorimetric measurements of the ammonia chemisorption

Using the methods of calorimetric and isosteric measurements of the ammonia adsorption, it is found that the lower limit of the heat of chemisorption in H-Y- and H-ZSM-5-zeolites is 60 kJ/mol. Dealumination of the Y- and ZSM-5-zeolites changes the total number of the acid sites as well as the strength and the strength distribution of the Brönsted sites. Within a margin of error of ± 10 %, there is a coincidence of the number of measured and calculated Brönsted sites (from the Al-content of the frame-work) in H-Y- zeolites.     

Occurrence of Ti3+ and Fe2+ in Mullite

Electron paramagnetic studies showed that Ti³⁺ and Fe²⁺ occur in mullites taken from a refractory material which was fused-cast under a reducing atmosphere. Exposure of the mullite samples to temperatures >1600°C caused oxidation of Ti³⁺ and Fe²⁺ to Ti⁴⁺ and Fe³⁺, respectively.