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  • Articles: DFG German National Licenses  (3)
  • 2005-2009
  • 1995-1999  (3)
  • 1945-1949
  • Alkaloids  (1)
  • Commercial steel  (1)
  • Modelling  (1)
Source
  • Articles: DFG German National Licenses  (3)
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Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Deep surface transformation and cladding of net shape commercial steel parts by simultaneous multiple pulsed laser radiation (1999)
    Springer
    Materials research innovations 3 (1999), S. 24-29 
    Details
    ISSN: 1433-075X
    Keywords: Key words Surface transformation ; Commercial steel ; Multiple pulsed laser radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  A key innovation in materials processing of pre-formed metal parts is reported herein. The ”QQC Process” involves the judicious selection of exposure parameters to three pulsed lasers (excimer, Nd-YAG and CO2) simultaneously for treatment of the work piece. Pre-formed commercial steel parts are hardened and/or toughened, and/or clad with TiC improving performance by at least one order of magnitude. Two examples are detailed: a punch for aluminum can production and a fuel injector nozzle. In the latter case it has been shown that some tens of microns of the metal are transformed to a noncrystalline phase, in the middle of the workpiece.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100190050121
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Assessment of sheet-metal bending requirements using neural networks (1996)
    Springer
    Neural computing & applications 4 (1996), S. 35-43 
    Details
    ISSN: 1433-3058
    Keywords: Automation ; Bending ; Forming ; Modelling ; Neural networks ; Sheet-metal ; Springback system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The springback behaviour of a sheet-metal is dependent on the properties of the metal and the bending conditions, namely the thickness of the sheet-metal, geometry of the tooling and the amount of force used for bending. Sheet-metal component manufacturing often requires near zero springback angle to obtain the correct shape of the product. An attempt has been made to model the non-linear relation between properties of the metal, the springback angle, geometry of the tooling and the bending force applied. Multilayer perceptron neural networks with a backpropagation learning algorithm were used to model the bending process. One set of data from bending experiments in a laboratory environment was used to train the networks. The networks were tested with the remaining set of experimental results. Then, the neural networks were used to predict the forces required for a number of bending experiments to achieve a zero springback angle. Validation of the neural network predictions was performed by trying to apply the predicted amounts of bending force in the physical experiments. The springback angles achieved were within ±1 degree, which is an acceptable range for the work. The research clearly demonstrates the applicability of neural networks to modelling the sheet-metal bending process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01413868
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Further Alkaloids Common to Ants and Frogs: Decahydroquinolines and a Quinolizidine (1999)
    Springer
    Journal of chemical ecology 25 (1999), S. 1179-1193 
    Details
    ISSN: 1573-1561
    Keywords: Alkaloids ; mass spectrometry ; infrared spectroscopy ; amphibians ; ants ; decahydroquinolines ; quinolizidines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three alkaloids—two minor decahydroquinolines (DHQs) and a major quinolizidine—were detected in an extract of a Brazilian myrmicine ant (Solenopsis (Diplorhoptrum) sp. picea group). One DHQ (3) was identical to a known frog-skin alkaloid, cis-195A (cis-5-methyl-2-propyldecahydroquinoline), while the second DHQ, an isomer of 3, designated 195J, was assigned a tentative cis-2-methyl-5-propyldecahydroquinoline structure (2) based on mass and infrared spectra. The third alkaloid proved identical to the frog-skin alkaloid 195C, for which a structure had not been previously proposed. Mass and infrared spectral analysis, including chemical ionization tandem mass spectrometry, indicated a 4-methyl-6-propylquinolizidine structure (1) for 195C. The four possible diastereomers were synthesized and the (6Z,10E)-4-methyl-6-propylquinolizidine diastereomer (1b) was identical to the natural alkaloid. Skin extracts of a population of a Madagascan mantelline frog contained, among other alkaloids, minor amounts of the same alkaloid triad 1–3 with 1 again predominating. The common occurrence of alkaloids 1–3 in both ant and frog supports the hypothesis that ants are a likely dietary source for sequestered frog-skin alkaloids and brings to six, the alkaloid classes common to ant and frog.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020898229304
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    Paper (German National Licenses)
    Fulltext
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