Thermodynamics of solid solutions with ordering tendencies

This paper describes a new procedure for the calculation of phase diagrams for quasibinary systems that show ordering phenomena near special stoichiometric compositions. The diagrams are calculated from excess Gibbs energy functions that are modulated in the solid state at the specified stoichiometric compositions by distribution functions of the Gauss type. These ‘Gaussian’ terms consider the contribution of the composition and temperature depending ordering energy to the excess Gibbs energy of the solid solution.

As the solid state is described in this way by a single continuous Gibbs function, the thermodynamic factor for interdiffusion in such quasibinary systems can also be derived as a single continuous function yielding negative values inside the miscibility gaps of the phase diagram.     

Maßnahmen zur Verbesserung der Richtigkeit von Stahlanalysen mit Automaten

Das Verhältnis der Vergleichbarkeit zwischen den Laboratorien zu der Wiederholbarkeit innerhalb der Laboratorien bei der Erstellung von analytischen Informationen läßt auf systematische Unterschiede zwischen den Laboratorien schließen. Die so konstatierte unterschiedlich gute Beschreibung der Realität soll durch Erzeugen analytischer Informationen größtmöglicher Richtigkeit verbessert werden. Das wird erreicht durch Referenz; das ist eine definierte Atomzahl des Analyten, die nach einer Voranalyse durch Rekonstitution der Probenportion in Form einer festen oder flüssigen Lösung den gleichen physikalischen und chemischen Bedingungen ausgesetzt wird wie die Analysenprobe. Es werden der Produktion angepaßte sekundäre Referenzproben erzeugt für die Eichkontrolle der Analysengeräte nach mehreren Methoden. Dabei soll schließlich durch minimalen Aufwand eine maximale Übertragung des Vertrauens in die Referenz auf den Analyten in der Analysenprobe gesichert werden.     

Results of radioisotope measurements at the NSF-University of Arizona tandem accelerator mass spectrometer facility

In this paper we will describe the operation of the University of Arizona tandem accelerator mass spectrometer (TAMS) facility, present results of some measurements performed to demonstrate the reliability of its performance, and describe several experiments which have been completed on samples of archaeologic and geophysical interest.     

Human CLAPS2 encoding AP17, a small chain of the clathrin-associated protein complex: cDNA cloning and chromosomal assignment to 19q13.2-->q13.3

We have cloned the cDNA for the human homolog of the rat AP17 gene, a small chain of the clathrin-associated protein complex AP-2. The cDNA is highly conserved between rat and human. Human AP17, gene symbol CLAPS2 (clathrin-associated/assembly/adaptor protein, small 3, 17 kDa), was assigned to chromosome region 19q13.2-->q13.3.     

The politics and policy of energy system transformation—explaining the German diffusion of renewable energy technology

To arrest climate change, a transition to a low-carbon economy must take place quite rapidly, within a century at most. Thus, the rate of diffusion of new technologies such as those for the generation of electricity from renewable energy sources becomes a central issue. This article explores the reasons for the particularly rapid spread of two such technologies in Germany, wind turbines and solar cells. We trace this diffusion to the nature of the policy instruments employed and to the political process which led to the adoption of these instruments. The analysis demonstrates how the regulatory framework is formed in a ‘battle over institutions’ where the German parliament, informed and supported by an advocacy coalition of growing strength, backed support policies for renewables sourced electricity against often reluctant governments and the opposition from nuclear and coal interests. It also demonstrates that this major political and environmental achievement carries a modest price if we consider total costs to society, i.e. including both subsidies to coal and the negative external economies of coal.     

Properties of ketimine/acetoacetate coated aluminum substrates

Based on ketimine/acetoacetate coating technology, a new two-component high solids primer for aerospace use has been developed. The objective was to formulate a chromate-free primer that may be applied to all relevant aluminum surfaces, particularly after chromate-free pretreatment. During development, interesting indications of good adhesion and good corrosion resistance were found. For confirmation and in order to optimize the primer, research was focused on the interfacial performance of the coatings on typical aerospace substrates. In this paper, therefore, the nature of the substrates, including their pretreatments, is discussed with initial emphasis on the nitric acid pickling pretreatment, used in place of chromate pretreatments with their desirable properties. Although aging in relevant electrolytes of such pretreated aluminum leads to an increase of the thin oxide layer by further hydration normally influencing negatively interfacial performances, cross cut adhesion values of the primer, or the primer/topcoat, before and after aging in several electrolytes, were good on clad as well as on non-clad material. This was confirmed by microscopic morphology assessment during similar aging processes of the coating/substrate systems. The hydration of the nitric acid pickled layer was not found in the presence of primer, with or without topcoat. Using electron energy loss spectroscopy, indications of a distinct chemical bond between the primer and the nitric acid pickled aluminum were revealed. Electrochemical impedance measurements, determining film resistances of the various coated panels, also showed good responses when the primer was pigmented with a selected chromate-free inhibitor. Finally, in line with the previous indications and due to the special interfacial performance, in the presence of chromate-free pretreated substrates, filiform corrosion resistance with chromate alternative pigmentation approaches that of chromated primers.