Zur Gültigkeit des Prinzips des quasistationären Zustandes

On the Validity of Steady State Principle Considering the simple case reduced concentrations were calculated by solving the exact differential rate equation by assuming a steady state and by assuming an „equilibrium”︁ between A₁ and A₂. In a broad field of reduced rate constants K_i/k₁ the range in which these assumptions are valid within ±5% was determined for different values of time.     

Sicherheitstechnische Überlegungen des Anlagenbauers und des Betreibers

Safety considerations of plant constructors and operators . Regular reviews of safety at predetermined intervals and with due regard to actual issues are proven means of ensuring the necessary high level of safety of chemical plants. Practical procedure and correlation with the design schedule of plants at a large chemical company are described.     

Theorie des Ultraschallabbaus auf der Grundlage des Perlschnurmolekül-Modells

The progress of ultrasonic degradation of polymers in solution can be described theoretically by the aid of the model of pearlstring molecules. According to this molecular model macromolecules are built up like a pearl necklace of so-called tertiary structural units. There is correlation between molecular weight of structural units to be obtained by measuring electron micrographs and limiting molecular weight after ultrasonic degradation. Experimental results suggest that molecules resembling a string of pearls are broken at the chain between its spherical units. Two imaginable ways of degradation mechanism are discussed: fragmentary and stepless depolymerization. In the first case the chain is broken between its structural units in several steps; in the second case the pearlstring molecule is broken to all its units in one step. Mathematical consideration has provided an equation for the stepless mechanism. By the aid of this equation the complete progress of depolymerization can be calculated if the limiting molecular weight after ultrasonic degradation is known. On the other hand the limiting molecular weight may be calculated if the beginning of degradation is known. Stepless and fragmentary degradation can be distinguished by comparing the experimentally determined depolymerization with the calculated one.     

Etude des propriétés des films préparés par evaporation des solutions d'un polymére dans différents solvants

Films of a plasticized random terpolymer were prepared by evaporation of solutions in several solvents. The glass transition temperatures of the films were determined and were found to follow the Fox's equation. Their tensile modulus, measured just below the glass transition temperature, was found to depend on the residual solvent content of the films.     

Einige neue Erkenntnisse zur Frage des Energiebedarfs und des Wärmeüberganges in Kratzkühlen

Some Recent Findings on Energy Requirement and Heat Transfer in Scraped Surface Hat Exchangers Scraped surface heat exchangers are widely used, especially in the food industry. In the past years, our knowledge on the physical relationship which are party based on theoretical considerations, could be extended. Certain rules could be derived from these findings, by which under certain conditions, the technical properties can be calculated in advance. Layout of equipment and their adaptation to definite working conditions were thus facilitated.     

Corrections des réponses des détecteurs placés à la sortie d'un CPG

Gel permeation chromatography only fitted with a refractometer is not sufficient for characterization of polymers. In the present study a combination of three detectors, a refractometer, a viscometer, and an IR-spectrophotometer is estimated to be necessary for analyzing polymers showing chemical and molecular heterogeneities. Unfortunately, using the crude results of these detectors for calculations leads to errors, the origins of which are identified and corrected.     

Die Bestimmung des Rauchpunktes II Einflüsse auf die Höhe des Rauchpunktes

Determination of Smoke Point II: Factors Affecting Smoke Point Investigations on the action of free fatty acids on the smoke point of fats showed a linear relationship between chain length and smoke point depression. Monoglycerides lower the smoke point very little, n-alkanals show no action. After a study of important parameters related to experiment and apparatus it was possible to optimize the smoke point determination using a new apparatus and significantly improve the method as compared to existing methods.     

Fettbegleitstoffe des Sanddornöls

Fat Accompanying Components of the Oil of Sea Buckthorn The water steam distillate mainly contains esters of ethanol and of isoamylalcohol with fatty acids and benzoic acid as well as benzaldehyde and benzylalcohol. The composition of the shell waxes and the unsaponifiable of flesh oil and seed oil were determined. The unsaponifiable of the flesh oil consists of long chain epoxides, alcohols, sterols and triterpenes. The main component of the unsaponifiable of the seed oil is phytol.