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Institution

DECHEMA

NonprofitFrankfurt am Main, Germany
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.
Topics: Corrosion, Oxide, Coating, Alloy, Catalysis


Papers
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Journal ArticleDOI
TL;DR: In this paper, a flow-robot system with Zn-ZSM-5 was used to convert ethane into aromatic hydrocarbons using nitrogen and hydrogen as carrier gases.
Abstract: Ethane was converted into aromatic hydrocarbons on H-ZSM-5 and Zn-ZSM-5 at 773 K in a flow reactor system using nitrogen and hydrogen as carrier gases. Residence time was varied by changing catalyst weights to obtain information about primary and secondary reaction steps. On H-ZSM-5 ethane conversion proceeds via formation of ethene and subsequent oligomerization. Oligomers undergo fast isomerization, cracking and cyclization leading to a broad spectrum of aromatics. Methane is a secondary product. Dehydrogenation reactions proceed irreversibly. Introduction of zinc species significantly enhances the aromatization activity of H-ZSM-5 on the one hand and causes a change of reaction mechanism on the other. Oligomerization of olefinic intermediates can take place at zinc sites. In nitrogen, aromatization of C 6 olefins is faster than isomerization and cracking of these oligomers. Dehydrogenation steps proceed reversibly. On using hydrogen as the carrier gas over Zn-ZSM-5, the conversion of ethane as well as the formation of aromatics decrease. Furthermore, aromatics richer in hydrogen (especially C 8 aromatics) are then formed preferentially.

14 citations

Patent
30 May 1980
TL;DR: In this paper, the authors describe an equipment for testing materials for the effects of stress corrosion cracking, which includes more than two tensioning units, each consisting of a base plate, two guide bars, an upper and a lower crossbeam, a locking system for the guide of the lower cross-beam and a connecting flange between the crossbeam and threaded bar.
Abstract: Equipment for testing materials for the effects of stress corrosion cracking, which includes more than two tensioning units, each consisting of a base plate, two guide bars, an upper and a lower cross-beam, a locking system for the guide of the lower cross-beam and a connecting flange between the cross-beam and a threaded bar for causing elongation of a test sample. The power drive supply block drives the threaded bar. A motor power unit is included in the power drive supply block and vertically-slippable gearing is inserted between the motor gearing and the block. The motor power unit consists of two stepping motors driving sun gears. The sun gears drive planetary gears which, by means of an arm, drive the drive shaft operatively associated with the threaded bar. In particular, the invention relates to equipment with six tensioning units comprising an automatic limit switch-off means and a lift system in the power drive supply block for separating the drive gears from the rest of the system. The angular speed of the stepping motors can be controlled by an electrically generated stepping frequency, the control unit, if desired, consisting of a microprocessor and a memory.

14 citations

Journal ArticleDOI
TL;DR: The use of an Ar/CH 2 F 2 -plasma for the F-PI 3 into small coupons led to a positive effect which was as good as the beamline implantation of elemental fluorine gas into samples of the same geometry as mentioned in this paper.
Abstract: Titanium aluminides are promising light weight materials for several high-temperature applications, e.g., in aero engines but due to their insufficient oxidation resistance at temperatures above roughly 800°C they cannot be used yet despite of their good mechanical high-temperature properties. The oxidation behavior of TiAl-alloys can be improved significantly by adding small amounts of fluorine into the subsurface zone of the components (microalloying). One possibility to apply fluorine to the surface of complex TiAl-components is the PI 3 -technique (plasma-immersion-ion-implantation). The use of an Ar/CH 2 F 2 -plasma for the F-PI 3 into small coupons led to a positive effect which was as good as the beamline implantation of elemental fluorine gas into samples of the same geometry. Turbine blades, as examples for real TiAl-components, were implanted with an optimum set of parameters. Post-exposure investigations like scanning electron microscopy revealed a thin protective alumina scale on the surface of the implanted samples in contrast to a thick mixed oxide scale (TiO 2 / A1 2 O 3 ) growing on untreated samples during high-temperature oxidation in air. The high-temperature oxidation resistance of several TiAl-alloys was improved by plasma-immersion-ion-implantation of fluorine. Small coupons showed a much lesser oxidation during high-temperature exposure after fluorine treatment than untreated samples. The performance of turbine blades for the low pressure compressor of a new generation of jet engines was also improved. Fluorine treated samples are covered with a thin, protective alumina scale after high-temperature exposure in air instead of a fast growing, nonprotective mixed oxide (TiP 2 /A1 2 O 3 ) scale which is found on untreated samples.

14 citations

Journal ArticleDOI
TL;DR: With the ospCSTR augmented by enzyme dosing, this work reports an economical process for a chemo-enzymatic epoxidation of sensitive terpenes like e.g., α-pinene.

14 citations

Journal ArticleDOI
TL;DR: This study is a first hint that a flavin-based EET might also take place in solventogenic Clostridia and highlights the importance of further investigation of flavin production and their involvement in EET mechanisms in different species.

14 citations


Authors

Showing all 760 results

NameH-indexPapersCitations
Wolf B. Frommer10534530918
Michael W. Anderson10180863603
João Rocha93152149472
Martin Muhler7760625850
Michael Hunger6029511370
Ivars Neretnieks442247159
Michael Schütze403436311
Jens Schrader381294239
Roland Dittmeyer312063762
Lei Li291984003
Dirk Holtmann291073033
Lasse Greiner26741994
Klaus-Michael Mangold23571590
A. Rahmel23591967
Gerhard Kreysa22781305
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
20227
202145
202053
201949
201844