Gewinnung von Euphorbiaöl unter besonderer Berücksichtigung der Abpreßbedingungen

Extraction of Euphorbia lathyris Oil by Pressing The seed of Euphorbia lathyris (caper spurge) seems to be interesting with respect to its high oil content (ca. 50% with more than 80% oleic acid). Like most other oilseeds considered to be “Renewable Raw Materials” Euphorbia lathyris is also cultivated in low quantities and, therefore, the oil of these seeds has to be extracted in small plants. When optimizing the pressing process of small plants the pre-treatment of seed and the oil processing have to be taken into consideration. With regard to the oil yield and the solids in the oil it is convenient to preheat the seed. The solids in the oil can be removed by sedimentation and filtration. An oil pressing plant is presented, which is built up according to a conception of the DIL and being equipped with a control unit for continuous operation.     

Einfluss der Plattendicke auf die Kontaktzeit beim elastischen Stoßvorgang

Using a free fall apparatus, the coefficient of restitution and the contact time of steel spheres at impact on thin gold‐coated glass plates were measured experimentally. The influence of the impact velocity, the particle size, and the plate thickness has been investigated. The measurements were evaluated using the Zener model. However, since the model merely considers energy dissipation due to elastic flexural waves and ignores additional energy dissipation by friction and viscous damping, the experimental values remain slightly below the theoretical Zener curve.     

Zur stromausbeute und kinetik elektrochemischer reaktionen bei hohen stromdichten unter stationären bedingungen

The investigation of the kinetics of electrochemical reactions at high current densities (20?300 A cm^?2) and high streaming velocities of the electrolyte, is difficult. Large ohmic drops occur which make the exact measurement of potential impossible. A method is reported for multiple electrodes in which the kinetic parameters are deduced, without measuring current-voltage curves, from the dependence of the current efficiency on total current density. The basis of the theory is discussed for a model system of two parallel Tafel type reactions. The anodic dissolution of iron with simultaneous oxygen evolution in KNO₃ and NaClO₃ solutions has been investigated experimentally.     

Hormonwirkungen auf die Haut unter besonderer Berücksichtigung der Steroid-Hormone

Action of Hormone on Human Skin with Special Consideration of the Steroid Hormones The action of various hormones on skin is outlined. Alterations of the skin due to such actions can also be caused by other medicaments. Parenteral or oral application of glucocorticoids lead to typical alterations of the skin, depending on the dose and duration of the treatment. If applied externally, the counteractions on the entire system are generally negligible, however, considerable local disorders, such as atrophy and striae can occur. The significance of the metabolism of androgens in the skin is discussed. The gestagens and the oestrogens, especially in the form of the “pill”, can cause typical pathogenetic alterations whose nature is yet unknown. Such actions can be reduced if the biological value of the anticonceptives in relation to “hormone-type” of the woman is taken into account.     

Zur kinetik der anodischen eisenauflösung bei hohen stromdichten unter stationären bedingungen

During the transpassive electrochemical dissolution of iron in nitrate solutions there appear oxide layers, of which the outward view changes with the current density. The oxide layers mainly consist of Fe₃O₄. The dissolution of iron at high current densities occurs through this layer. From measurements of the current efficiency kinetic parameters are deduced. According this, the reaction charge number is +2 and the reaction order +1 concerning nitrate ions. The Tafel slopes in nitrate solutions are 40 mV and in chlorate solutions 30 mV. Active, passive and transpassive dissolutions of iron are compared with each other and characteristic differences are pointed out. In the transpassive region there exists no closed oxide layer of γ-Fe₂O₃, which responds for passivity. For this reason the high rate of dissolution and the reaction charge number of +2 may be explained.     

Der Einfluß von Antioxidantien auf die Wirkung von UV-Absorbern in verschiedenen Lacksystemen

Influence of Antioxidants on the Action of UV-Absorbers in Various Coating Systems Antioxidants on the basis of amines are undesirable as components of complex UV-absorbers due to their low stability in light. The stability of phenolic antioxidants is largely dependent on the structure of their substituents. Bis-(3,5-ditert.-butyl-4-hydroxy-benzyl)-derivatives of malonic esters, cyanoacetic esters and phosphonoacetic esters possess a good stability in heat and light and they exhibit a certain UV stabilizing action even when used alone. The author investigated the influence of these phenols on the action of UV-absorbers in various coating systems. It could be established in general that although the above phenols improved the action of UV-absorbers, however, they could not even partially substitute the latter without diminishing their action.     

Genetische Einflüsse auf die Talgdrüsensekretion unter besonderer Berücksichtigung der Atopien

Genetic Influence on the Sebaceous Gland Function with Special Consideration of Atopy Twin studies have demonstrated genetic control of sebum production. Probably many separate genes are involved. Xerosis of the skin due to reduced sebum production is an important phenotypic marker of the atopic individual. However, the genetics of sebaceous gland function in atopy cannot be separatedly regarded as yet. Different possible mechanisms of the genetic influence on sebum production are discussed.     

Zum Einfluß des Polymermolekulargewichts auf das Phasenverhalten von Gas-Polymer-Systemen unter Hochdruck

The phase behaviour of gas-polymer-systems, which is important in the polymerization of gaseous monomers and in the separation of the polymers formed, was studied at a constnat temperature of 130°C and at pressures of 100–2000 bar. Dissolving polyethylenes of different average molecular weights in compressed ethylene, it was found, that the solubility of the polymer is decreased with increasing molecular weight of the polymer. The maximum in pressure of the phase-boundary curves increases and is shifted towards lower polymer concentrations. The analysis of the samples from the gas and the liquid phase showed that the average molecular weight as well as the molecular weight distribution of the polymer is different in the two phase and differs also from the polymer in the homogeneous mixture. The results were compared with the data of other authors. Furthermore it was tried to show with other systems.     

Über die Veränderung einiger Qualitätsmerkmale bei verschiedenen Ölleinsorten unter kontrollierten Klimabedingungen

Alteration of Several Quality Characteristics of Different Varieties of Linseed under Controlled Climatic Conditions In a phytotron experiment, 9 varieties of linseed from different countries were grown from flowering till ripening under 2 different day lengths (12^h and 19^h), 2 different temperatures (15°C and 23°C) as well as 2 different humidities (85% and 50%). Using these plant materials, the influence of climatic factors, such as photoperiod, temperature and humidity, on several important quality characteristics of linseed were studied with the aim to explain the differences observed in a world-wide field study¹. The crude fat content was generally increased at lower temperatures, however, several varieties behaved oppositely, yielding a higher oil content at higher temperatures. Also with regard to crude protein content, several interactions were found between the varieties and the climatic factors, so that no distinct negative correlation was obtained between crude fat content and crude protein content. These interactions, which were also observed in other quality criteria as well as in field experiments, hardly permit the exact prediction of the quality of linseed of various provenances if the variety is not known.     

Einfluß von Carboxymethylcellulose auf das Verhalten von Tonsuspensionen unter besonderer Berücksichtigung des Tiefbohrsektors

The function of drilling fluid includes the removal of the cuttings from the bore hole, the supporting of the hole wall, the cooling of the bit, and the maintenance of the hydrostatic equality with the formation pressure. The clay suspension preferred to employ these purposes possess adequate flow limits and gel strengths, the water retensivity however is insufficient. With the addition of carboxymethylcellulose the dispersion of clay in water and the water retensivity are improved. In the present publication, the influence of carboxymethylcellulose in clay-water and sodiumchlorid-saturated clay-water suspension on the rheological properties and the water retensivity are investigated.