Kristallin-flüssige 1,3,4-Thiadiazole. II [1]. 1,3,4-Thiadiazole mit Cyclohexanstrukturfragmenten

Liquid Crystalline 1,3,4-Thiadiazoles. II. 1,3,4-Thiadiazoles with Cyclohexanefragments Preparation and liquid crystalline properties of disubstituted 1,3,4-thiadiazoles (1 and 2) are described. The mesomorphic behaviour of the title compounds is compared with their benzoate analogues. The dielectric anisotropy of these compounds is negative.     

Halbkornmethode zur Bestimmung des Amylosegehalts in Gerste

A Half-kernel Method for Determination of the Amylose Content of Barley. A method, which can determine the amylose content of a single kernel, is of importance for the use of amylose mutants in plant breeding. In this paper a potentiometric titration for the determination of the amylose content of a matured half kernel of barley is described and the evalution of the titration-curves is discussed. This method allows to differentiate between various barley lines and varieties in genotypes which differ in amylose content.     

Untersuchungen zur Amylosebestimmung in proteinreichen Stärkerohstoffen,insbesondere Erbsen

Investigations on the Amylose Determination in High Protein Starch Source Materials, Especially Peas. The proposed utilization of amylose rich starches requires different methods of amylose determination. In addition to laboratory methods also simple tests are important to that. Because the discussed legume starches are hardly investigated, first of all the suitability of the amperometric iodine titration had to be checked. Then a more easier work was described. In the case of routine analyses a modified test procedure was compared with the method of iodine titration.     

环锭纺的发展潜力

目前存在3个关键因素导致环锭纺产量无法进一步提高。介绍了一些有利于未来环锭纺技术进一步发展的基本情况。详细分析了环锭纺工序中的能耗问题,这是性能能否提高的基础。环锭纺产量的提高,不仅是技术上是否可行的问题,更重要的是能够获得良好的经济效益。     

Bücherschau

Ohne Zusammenfassung VDI     

Modeling of thermal hydraulic instabilities in single heated channel loop during startup transients

A thermal hydraulics computer code was developed to simulate the geysering instability in a natural circulation system starting from subcooled conditions and to assess the impact of the system pressure and channel inlet subcooling on the inception of instability. The formulation of thermal hydraulics is inherently general and accounts for both single-phase liquid flow and nonhomogeneous, nonequilibrium two-phase flow. The computer code is based on momentum integral method where the current practice of basing fluid properties on the system averaged pressure has been relaxed and the local properties are based on local pressures estimated using the shape of steady-state pressure distribution, thereby, improving the predictions while preserving the computation speed, one of the important strength of the integral methods. This is an important modeling feature since the local vapor generation rate depends on local saturation temperature The methodology has been validated with the experiments conducted to investigate the instabilities in a low pressure natural circulation loop at low powers and high inlet subcoolings. The numerical simulations predicted periodic channel flow reversal, which is one of the feature of condensation-induced geysering. Basing local properties on local pressures instead of system average pressure led to decrease in the discrepancy in the prediction of the positive side amplitude from 40% to 6% and in the frequency from −15% to 5%. In addition, it was observed that the start-up instability can be avoided by increasing system pressure or by decreasing channel inlet subcooling. This study showed that the integral method coupled with local pressure variation for the vapor generation model is suitable to predict startup or geysering transients.