Untersuchung des Passivierungsmechanismus von Eisen in Phosphatelektrolyten an erosiv beanspruchten Oberflächen

Investigation into the passivation mechanism of iron in phosphate electrolytes on surfaces exposed to erosive attack On iron electrodes in neutral phosphate electrolytes by continuous solid particle impingement a reaction layer is formed within the transition potential region under anodic polarization. XPS and AES investigations show that the reaction layer formed under impingement will be replaced by an oxide layer during the transition into the passive state under simultaneous decrease of the layer thickness. The active/passive transition in phosphate electrolytes may be attached to the equilibrium potential of the reaction . According to this thermodynamic interpretation of both the active/passive transition and the passive/active transition, respectively on iron in presence of phosphate ions may be described as the Fe(II)/Fe(III)-redox reaction with two solid phases, the iron(II)-phosphate phase and the iron(III)-oxide phase. The increase of the interfacial dynamic processes at the solid/liquid interface causes in consequence of the solid particle impingement that thermodynamic laws govern the course of reactions.     

The evaluation of cell nuclei staining parameters regarding the reproducibility of fluorescence measurements.

The present methodological study is an attempt to optimize the staining parameters for a quantitative DNA determination of fluorescent cells. The application of pure dyes and a precise control of the staining procedure are preliminary conditions which have to be fulfilled, because the reproducibility of measurements is in this connection the most important criterion for a quantitative DNA related analysis of cell population. Chicken erythrocytes and isolated nuclei were applied as biological test objects. The staining procedure with acridine derivatives (acriflavine, proflavine, rivanol) was performed in accordance with the fluorescence-Feulgen reaction. The influence of staining parameters, such as (1) pH and (2) dye concentration of the staining solution, were evaluated regarding the spectral behaviour, the total fluorescence intensity, and the reproducibility of results.     

Effect of wind and temperature on concentrations of Pb in urban air. I. Example of a location situated under the direct influence of intense traffic

A simple mathematical relationship has been established between the Pb concentrations in the ambient air in the vicinity of a heavy-traffic road and some meteorological parameters (wind speed and direction, temperature). The application of this relationship permits the interpretation of the variations in concentrations with respect to the time of day and period of the year.     

Harderian gland exudates in the male Meriones unguiculatus regulate female proceptive behavior, aggression, and investigation.

Replicated an earlier finding by the present authors (see record 1986-08500-001) that female proceptive behaviors toward Harderianectomized males are diminished. In the present study, it was shown that estrous females directed fewer proceptive acts toward males lacking Harderian glands. In addition, it was found that females were more defensively aggressive toward Harderianectomized males and preferred to spend more time in the vicinity of intact males. It is speculated that Harderian spread allows the female to assess the reproductive competence of the male. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ventral scent marking in Meriones unguiculatus may contribute to thermoregulation.

Conducted 3 experiments with adult male gerbils to demonstrate that ventral scent marking can act to transfer body heat to the object marked. Exp I, with 16 Ss, showed that surgical removal of the ventral gland pad in 8 Ss reduced the amount of heat transferred by 50%, even though intact and glandless Ss did not differ in the average frequency of scent marking. Exp II, with the same 16 Ss used in Exp I, demonstrated that the difference in heat transfer due to the presence or absence of the scent pad was not due to differential pressure applied to the substrate during marking. Exp III, with 14 Ss, showed that the pattern of ventral hair spread that occurred as an S moved over an object was different between intact and glandless Ss but that this difference did not account for the difference in heat transfer. It is suggested that heat transfer to the environment with ventral scent marking may increase thermoregulatory competence and also may function to volatilize sebum used in chemocommunication. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Zur Elektrodenkinetik von Reinst – Eisen im Phosphatelektrolyten bei Feststoffeinschlag (Simulation von Erosionskorrosion)

Electrode kinetics of high purity iron in phosphate electrolytes under solid particle impact (Simulation of erosion corrosion) Erosion-corrosion of high purity iron was simulated by means of a vibration cell in a neutral phosphate electrolyte. The investigations were carried out to explain the initiation processes of this type of corrosion. The results confirm the general conception of the central role of reaction layer destruction in erosion-corrosion processes. Under these conditions a qualitative change in reaction layer formation occur. By solid impact the layers are destroyed locally and so conditions of pit nucleation exist. The destruction of the layers depends on the action of shear forces resulting from tensile or compressive strains.     

Das Zeitstandverhalten von Feinblei

The creep behaviour of sheet lead . The exact dimensioning of building components subject to deformation through creep is becoming an increasingly important factor in modern engineering. A search of the literature for the mechanical properties of sheet lead shows that differing statements are made on the mechanical behaviour of lead (1–3). Above all, it is repeatedly found that the strength properties over long periods are derived from short-term trials and that characteristic values such a expansion rate and creep rate are given, which have been determined from such trails. In order that definite information can be given on the strength properties of lead and its alloys used for technical purposes, genuine creep trails over long periods are necessary.     

Das Zeitstandverhalten des Stahles X 10 NiCrAlTi 32 20 bei hohen Temperaturen und langen Zeiten

Creep Behaviour of Steel × 10 NiCrATi 32 20 at Elevated Temperatures and Over Long Periods. The demands made on the quality of materials for chemical plants are continually increasing. Not only has there been a changeover to large units and an increase in the pressures and temperatures employed, but for technical and financial reasons the properties of the materials must be optimally utilized. In components subjected to the highest stresses due to pressure and temperature, the service life has to be calculated with the aid of creep strength characteristics. On the basis of the austenitic material × 10NiCrAlTi 32 20 an attempt is made, with the aid of creep strength characteristics, which have been determined in our own long-time test, to make a statement regarding the structural states existing at defined times and to draw conclusions for the use of this material.     

Der Einfluß von Niob auf die Zeitstandfestigkeit von Schleudergußlegierungen mit 25% Chrom und 20% Nickel

The Influence of Niobium on the Creep Rupture Strength of Centrifugally Cast Alloys Containing 25% Chromium and 20% Nickel . The material most frequently used in chemical furnace construction is G-X 40 CrNiSi 25 20 steel. Because of the change to larger units and the increase in operating pressure and temperature it is often no longer possible to obtain sufficiently long on-stream times with this alloy. The development consequently turned to new alloy variants which held out promise of an improved creep rupture strength, with undiminished resistance to corrosion. By adding niobium to alloys containing 25% chromium and 20% nickel it is possible to improve the thermal stability of centrifugal castings. The creep rupture strength data of two niobium-containing melts of this type of steel were determined experimentally. The creep rupture strength characteristics of the CrNi-containing centrifugally cast alloys with and without niobium was compared by platting the scatter jointly on one chart.