Schmelzmetallurgische Beurteilung von nichteisen- metallh?ltigen Schlacken

The behaviour of different materials at increasing temperatures, especially the melting, is determinable by various methods. The information from technical literature, thermodynamical calculations by FactSage and practical measurements by a heating microscope are compared for the system Cr₂O₃?CFeO_x?CZnO, which is essential for EAF dusts. The results display that the technical literature provides only restricted information for inconvenient systems. The practical measurements are otherwise device-related limited by the maximum tolerable operating temperature (1700 °C). However, the obtained data exhibit the best reference to the industrial praxis. Finally, thermodynamical calculations are possible for any temperature. However, there are often no optimised thermodynamical data bases available for rather complex systems so that simplifications and assumptions are required. This possibly leads to increasing inaccuracy of the obtained results.     

Toxizitätsreduktion durch (Grundwasser-) Sanierung?

The usage of an automatized and continuously (on-line) working biomonitor for the surveillance of groundwater remediation is presented and the data are compared to different discontinuous acute biotests. The use of an on-line biomonitor at the SAFIRA groundwater remediation testsite showed to be superior to the discontinuous tests. The long-time surveillance of two different remediation techniques revealed a decrease in remediation efficiency of one technique while the other technique -using activated carbon- did not show any reduction in efficiency. The validation of these results with other acute biotests (algae, fishembryo, daphnia and genotoxicity) indicated a complex groundwater contamination which can not be explained by the quantitatively main contaminant monochlorobenzene. It is suggested to use ecotoxicological biotests and knowledge in parallel to the conventional chemical analysis before a remediation strategy is designed. All anthropogenic contaminations (toxic or unwanted) should be identified beforehand such that the developed remediation techniques would be more target-oriented.     

Sanierungsforschung in regional kontaminierten Aquiferen (SAFIRA) – 1. Information zum Forschungsschwerpunkt am Standort Bitterfeld

The SAFIRA-project (remediation research in regionally contaminated aquifers) focuses on innovative in situ remediation technologies to treat complex groundwater contamination. For this purpose, a model site located in Bitterfeld, Germany, was selected. The site is heavily contaminated with aliphatic and aromatic chlorinated hydrocarbons. The goal of the project is to develop, test and optimize new technologies of reactive barriers under controlled in situ conditions in a pilot plant. In order to create the necessary basis for this model project, the hydrogeological and hydrogeochemical conditions at the selected field site were investigated and various technologies for the design of the in situ pilot plant were examinated. Small-scale laboratory studies and tests in a mobile test unit (scale 1 m) were carried out in order to test the technologies prior to their application in the field. The technologies now tested in the reactive columns at the pilot plant include physico-chemical, microbial and combined techniques.     

New sealing concept for planar solid oxide fuel cells

A key element in developing high-performance planar solid oxide fuel-cell stacks is the hermetic seal between the metal and ceramic components. Two methods of sealing are commonly used: (a) rigid joining and (b) compressive sealing. Each method has its own set of advantages and design constraints. An alternative approach is currently under development that appears to combine some of the advantages of the other two techniques, including hermeticity, mechanical integrity, and minimization of interfacial stresses in the joint substrate materials, particularly the ceramic cell. The new sealing concept relies on a plastically deformable metal seal; one that offers a quasi-dynamic mechanical response in that it is adherent to both sealing surfaces, i.e., non-sliding, but readily yields or deforms under thermally generated stresses. In this way, it mitigates the development of stresses in the adjacent ceramic and metal components even when a significant difference in thermal expansion exists between the two materials. The pre-experimental design of the seal, initial proof-of-principle results on small test specimens, and finite-element analyses aimed at scaling the seal to prototypical sizes and geometries are described herein. This paper was presented at the ASM Materials Solutions Conference & Show held October 18–21, 2004 in Columbus, OH.     

Gezielte Manipulation von Mikropartikeln in einem Plasma. Manipulation of micro‐disperse particles in a process plasma

An optimal treatment (surface modification, coating) of micro‐disperse materials (powder, granulate, fibres etc.) by a process plasma requires the understanding of plasma‐particle interaction. For this purpose, related experimental investigations in a novel set‐up PULVA‐INP will be presented.     

Long chain alkanesulfonates and 1-hydroxy-2-alkanesulfonates: Structure and property relations

Even chain sodium alkanesulfonates from the Strecker reaction, odd chain sodium alkanesulfonates from the alkaline decarboxylation of α-sulfo acids, and sodium 1-hydroxy-2-alkanesulfonates from the reduction of esters of α-sulfo acids were compared with respect to Krafft point, critical micelle concentration, detergency and foam height. Sodium alkanesulfonates and crude fusion products from the α-sulfo acids (mixtures of alkanesulfonates of one less carbon atom with a lesser amount of a soap of two less carbon atoms) are more soluble and have better detergent and foaming properties. Sodium 1-hydroxy-2-alkanesulfonates resemble monosodium salts of α-sulfo acids. Alkanesulfonic acids and 1-hydroxy-2-alkane-sulfonic acids obtained from the sodium salts by ion exchange have lower Krafft points and are more readily soluble. The critical micelle concentrations of 1-hydroxy-2-alkanesulfonic acids and α-sulfo acids are nearly the same and about equal to those of alkanesulfonic acids of one less carbon atom. Presented at the AOCS meeting in Toronto, Canada, 1962. A laboratory of the E. Utiliz. Res. & Dev. Div., ARS, U.S.D.A.     

Characterization of metal (Fe,Co, Ni,Cu) and fluorine codoped barium strontium titanate thick-films for microwave applications

The influence of codoping of Fe, Co, Ni, Cu as acceptors and F as donor on the dielectric properties of screen-printed Ba_0.6Sr_0.4TiO₃ ceramic thick-films has been investigated. The undoped and codoped Ba_0.6Sr_0.4TiO₃ powders were synthesized through a sol-gel route. The thermal gravimetric analysis revealed the difference of the thermal decomposition behaviour between the undoped and codoped precursors. The ceramic powders were characterized with x-ray diffraction, scanning electron microscopy and BET measurements. Larger crystallite sizes of the codoped powders were observed. The densification behaviour of the powders was recorded by dilatometry and indicated that codoping influences the sintering mechanism. The permittivity, dielectric loss and tunability of the undoped and codoped thick-films were characterized with coplanar waveguide structures up to 30 GHz.     

Textures on Rank‐1 Lattices

Storing textures on orthogonal tensor product lattices is predominant in computer graphics, although it is known that their sampling efficiency is not optimal. In two dimensions, the hexagonal lattice provides the maximum sampling efficiency. However, handling these lattices is difficult, because they are not able to tile an arbitrary rectangular region and have an irrational basis. By storing textures on rank‐1 lattices, we resolve both problems: Rank‐1 lattices can closely approximate hexagonal lattices, while all coordinates of the lattice points remain integer. At identical memory footprint texture quality is improved as compared to traditional orthogonal tensor product lattices due to the higher sampling efficiency. We introduce the basic theory of rank‐1 lattice textures and present an algorithmic framework which easily can be integrated into existing off‐line and real‐time rendering systems.