DECHEMA

About: DECHEMA is a nonprofit organization based out in Frankfurt am Main, Germany. It is known for research contribution in the topics: Corrosion & Oxide. The organization has 756 authors who have published 1307 publications receiving 25693 citations.

The halogen effect for improving the oxidation resistance of TiAl-alloys

Abstract: Alloys based on TiAl intermetallics are potential candidates for high temperature applications in e.g. aero engines or automotive engines because of their low specific weight and good high temperature strength. To improve their oxidation resistance at temperatures up to 1000°C the halogen effect offers an innovative and cost-effective way. The addition of small amounts of halogens into the surface leads to the preferential formation of gaseous aluminium halides which are oxidised to aluminium oxide during their outward migration forming a dense, protective and slowly growing alumina scale on the surface. In this paper two methods were used to apply halogens to the surface, ion implantation (F and Cl) and a liquid phase process (F). Ion beam analysis with detection limits in the ppm-range was applied to quantify the needed amount of halogens to achieve the halogen effect. Thermocyclic oxidation experiments at 900°C were performed in laboratory air and wet air. Depth concentration profiles of fluori...

Light-Accelerated Biocatalytic Oxidation Reactions

Abstract: The influence of (visible) light on the performance of laccase mediator systems (LMS) was investigated. As a model reaction, LMS-mediated nicotinamide adenine dinucleotide (NAD+) regeneration to promote alcohol dehydrogenase catalyzed oxidation reactions was examined.

A simplified process design for P450 driven hydroxylation based on surface displayed enzymes.

Abstract: New production routes for fine and bulk chemicals are important to establish further sustainable processes in industry. Besides the identification of new biocatalysts and new production routes the optimization of existing processes in regard to an improved utilization of the catalysts are needed. In this paper we describe the successful expression of P450BM3 on the surface of E. coli cells with the Autodisplay system. The successful hydroxylation of palmitic acid by using surface-displayed P450BM3 was shown. Besides optimization of surface protein expression, several cofactor regeneration systems were compared and evaluated. Afterwards, the development of a suitable process for the biocatalytic hydroxylation of fatty acids based on the re-use of the catalysts after a simple centrifugation was investigated. It was shown that the catalyst can be used for several times without any loss in activity. By using surface-displayed P450s in combination with an enzymatic cofactor regeneration system a total turnover number of up to 54,700 could be reached, to the knowledge of the authors the highest value reported for a P450 monooxygenase to date. Further optimizations of the described reaction system can have an enormous impact on the process design for more sustainable bioprocesses. Biotechnol. Bioeng. 2016;113: 1225-1233. © 2015 Wiley Periodicals, Inc.

Environmental impacts of nanomaterials: providing comprehensive information on exposure, transport and ecotoxicity - the project DaNa2.0

Abstract: Background Assessing the impact of new technologies or newly developed substances on our environment is a challenge, even more so if the applied test methods - both toxicological and analytical - are often found to be inadequate and need amendments or even new developments as it is in the case of nanotechnology. This is illustrated by numerous publications in the field of nano-ecotoxicology which although they have been investigating the impact of a number of nanomaterials on several organisms almost never allow for explicit statements on potential hazards of these nanomaterials. This fact not only hampers the knowledge communication to all non-scientists (e.g. consumers) but it also complicates the transfer of the obtained results for other scientists.