‘Fragile Superconductivity’: A Kinetic Glass Transition in the Vortex Matter of the High-temperature Superconductor YBa2 Cu3O7-δ

Using high-resolution thermal expansion and magnetization measurements, we provide experimental evidence for a kinetic glass transition in the vortex matter of YBa₂Cu₃O_7-δ with some disorder. This transition, which represents the true superconducting transition in a magnetic field, exhibits many of the features of the usual glass transition found in supercooled structural liquids such as window glass. We demonstrate, using both kinetic and thermodynamic criteria, that this vortex matter is the most fragile system known to date, which we argue makes it possible to investigate the behavior very close to the Kauzmann temperature. Vortex matter, we suggest, may be a model system to study glassy behavior in general, which is expected to lead to a better understanding of the strong-fragile behavior in structural glasses.     

Organometallic Conjugated Polymer Networks

Despite the diverse research activities focused on the chemistry, material science and physics of conjugated polymers, the feature of conjugated cross-links, which can provide electronic communication between chains, has received little attention. This situation may reflect the challenge to introduce such cross-links and retain adequate processability. On the basis of selected recent examples, the present review attempts to give a concise overview of the synthesis, processing and electronic properties of the important class of organometallic networks, which are formed through coordination bonds between ligand sites comprised in the organic semiconductor and metallic cross-links. These metallopolymers are also intractable but are often readily accessible via either ligand-exchange reactions or, alternatively, the polymerization of pre-fabricated metal–ligand complexes. If the electronic potentials of the cross-links are tailored to match those of the linear segments, these moieties allow for adequate electronic coupling. An erratum to this article can be found at     

In vitro microbial metabolism of fumonisin B1

There is a lack of information on the effect of swine caecal microbiota on fumonisin metabolism. In this in vitro study, the biotransformation of fumonisin B₁ (FB₁) by the gut microbiota of adult, healthy pigs was examined. Suspensions of caecal contents and McDougall buffer solution were incubated anaerobically with pure FB₁ for 0, 12, 24, 48 and 72 h. After 48 h, the conversion of FB₁ to partially hydrolysed FB₁ (46%) was nearly equal to the percentage ratio of FB₁, while by 72 h it was 49%. In vitro, the conversion of fumonisin B₁ to aminopentol was less than 1%. The results show that the caecal microbiota are capable of transforming fumonisin B₁ to the above metabolites. Further studies on FB₁ metabolism in the small intestine are clearly justified.     

A pragmatic type concept for Prolog supporting polymorphism, subtyping, and meta-programming

Approaches to typing logic programs often exclude various features of Standard Prolog. The system “Typical for annotated Prolog” (TaP) is a pragmatic approach to type checking programs written in Prolog without restricting the scope of the language. TaP checks Prolog programs that are extended with type declarations that support parametric polymorphism and subtyping. The purpose of this paper is to present an approach that extends Typical by meta-types for handling Prolog meta-programming techniques.     

Die neue Hauptverwaltung der THS in Gelsenkirchen – Umnutzung einer Zeche zu einem modernen Verwaltungsgebäude

The new main office of the THS in Gelsenkirchen – conversation (revitalization) of an old mine into an office building. Many industrial buildings of the heavy industry are no longer in use. Many are dismantled and the sites are used in a different way. Some of them are worth preserving for the future such as the filter building of the mine “Nordstern” in Gelsenkirchen, which was designed by the architects Schupp and Kremmer This article describes the conversion of the multi-storied building of the mine into an office building. Special emphasis is placed on the connection between the distinctive technical features of the existing building and the chosen solutions for the conversion.     

Optimization and Biomass Utilization in Heavy Metal Recycling

Environmental legislation, limited resources as well as high metal prices force the metallurgical industry more and more to make use of secondary materials. For this, also residues from metal production are nowadays considered as a possible resource. Due to their often complex structure and the presence of a multi-metal-system, efficient recycling of such materials is not easy to realize and suffers from various problems. The Christian Doppler Laboratory for Optimization and Biomass Utilization in Heavy Metal Recycling together with its partner companies Befesa R&D, voestalpine Stahl Linz, RHI, and Aurubis investigate alternative strategies and optimization possibilities for the considered residues. The achievements of three years’ activity in the major fields of the CDL, characterization of the complex input materials, upgrade of the product quality of recycling processes, utilization of biomass in the form of charcoal for use as a reducing agent and simultaneous recovery of valuable metals are described in the paper.