@article{CserDonnerSchwarzetal.2002, author = {Cser, Adrienn and Donner, Reik Volker and Schwarz, Udo and Otto, Andreas H. and Geiger, M. and Feudel, Ulrike}, title = {Towards a better understanding of laser beam melt ablation using methods of statistical analysis}, isbn = {88-87030-44-8}, year = {2002}, abstract = {Laser beam melt ablation, as a contact free machining process, offers several advantages compared to conventional processing mechanisms. Although the idea behind it is rather simple, the process has a major limitation: with increasing ablation rate surface quality of the workpiece processed declines rapidly. The structures observed show a clear dependence of the line energy. In dependence of this parameter several regimes of the process have been separated. These are clearly distinguishable as well in the surfaces obtained as in the signals gained by the measurement of the process emissions which is the observed quantity chosen.}, language = {en} } @article{FeudelJansenKurthsetal.1997, author = {Feudel, Ulrike and Jansen, Wolfgang and Kurths, J{\"u}rgen and Schwarz, Udo and Voss, Henning U.}, title = {Solar variability : simple models and proxy data}, isbn = {4-274-90187-4}, year = {1997}, language = {en} } @article{BubeNetoDonneretal.2006, author = {Bube, Kevin and Neto, Camilo Rodrigues and Donner, Reik Volker and Schwarz, Udo and Feudel, Ulrike}, title = {Linear and nonlinear characterization of surfaces from a laser beam melt ablation process}, issn = {0022-3727}, doi = {10.1088/0022-3727/39/7/011}, year = {2006}, abstract = {We apply linear and nonlinear methods to study the properties of surfaces generated by a laser beam melt ablation process. As a result we present a characterization and ordering of the surfaces depending on the adjusted process parameters. Our findings give some insight into the performance of two widely applied multifractal analysis methods-the detrended fluctuation analysis and the wavelet transform modulus maxima method-on short real world data}, language = {en} } @article{CserDonnerSchwarzetal.2001, author = {Cser, Adrienn and Donner, Reik Volker and Schwarz, Udo and Feudel, Ulrike and Otto, Andreas H.}, title = {Statistical parameters of a control strategy of laser beam melt ablation}, year = {2001}, abstract = {Laser beam melt ablation - a contact-free machining process - offers several advantages compared to conventional processing mechanisms: there exists no tool wear and even extremely hard or brittle materials can be processed. During ablation the workpiece is molten by a CO2-laser beam, this melt is then driven out by the impulse of a process gas. The idea behind laser ablation is rather simple, but it has a major limitation in practical applications: with increasing ablation rates surface quality of the workpiece processed declines rapidly. At high ablation rates, depending on the process parameters different periodic-like structures can be observed on the ablated surface. These structures show a dependence on the line energy, which has been identified as a fundamental control parameter. In dependence on this parameter several regimes with different behaviours of the process have been separated. These regimes are distinguishable as well in the surfaces obtained as in the signals gained by the measurement of the process emissions. Further aim is to identify the different modes of the system and reach a deeper understanding of the dynamics of the molten material in order to understand the formation of these surface structures. With this it should be possible to influence the system in the direction of avoiding structure formation even at high ablation rates. Relying on the results on-line monitoring and control of the process should be studied.}, language = {en} } @article{JobstKnoblochLeitneretal.2006, author = {Jobst, Anne and Knobloch, Eberhard and Leitner, Ulrike and Mikosch, Regina and Pieper, Herbert and Schwarz, Ingo and Werner, Petra and Werther, Romy}, title = {Margot Faak zum 80. Geburtstag}, volume = {VII}, number = {13}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1617-5239}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-35594}, pages = {8 -- 9}, year = {2006}, language = {de} }