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Veröffentlichungen am Institut für Mathematik seit 1990

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Boeck, Thomas; Terzijska, Dzulia; Eichfelder, Gabriele;
Maximum electromagnetic drag configurations for a translating conducting cylinder with distant magnetic dipoles. - In: Journal of engineering mathematics - Dordrecht [u.a.] : Springer Science + Business Media B.V, ISSN 1573-2703, Bd. 108 (2018), 1, S. 123-141

We report a semianalytic and numerical investigation of the maximal induced Lorentz force on an electrically conducting cylinder in translation along its axis that is caused by the presence of multiple distant magnetic dipoles. The problem is motivated by Lorentz force velocimetry, where induction creates a drag force on a magnet system placed next to a conducting flow. The magnetic field should maximize this drag force, which is usually quite small. Our approach is based on a long-wave theory developed for a single distant magnetic dipole. We determine the optimal orientations of the dipole moments providing the strongest Lorentz force for different dipole configurations using numerical optimization methods. Different constraints are considered for dipoles arranged on a concentric circle in a plane perpendicular to the cylinder axis. In this case, the quadratic form for the force in terms of the dipole moments can be obtained analytically, and it resembles the expression of the energy in a classical spin model. When all dipoles are equal and their positions on the circle are not constrained, the maximal force results when all dipoles are gathered in one point with all dipole moments pointing in radial direction. When the dipoles are equal and have equidistant spacing on the circle, we find that the optimal orientations of the dipole moments approach a limiting distribution. It differs from the so-called Halbach distribution that provides a uniform magnetic field in the cross section of the cylinder. The corresponding force is about 10% larger than that for the Halbach distribution but 60% smaller than for the unconstrained dipole positions. With the so-called spherical constraint for a classical spin model, the maximal force can be found from the eigenvalues of the coefficient matrix. It is typically 10% larger than the maximal force for equal dipoles because the constraint is weaker. We also study equal and evenly spaced dipoles along one or two lines parallel to the cylinder axis. The patterns of optimal magnetic moment orientations are fairly similar for different dipole numbers when the inter-dipole distance is within a certain interval. This behavior can be explained by reference to the magnetic field distribution of a single distant dipole on the cylinder axis.



https://doi.org/10.1007/s10665-017-9916-8
Dietrich, Thomas; Krug, Silvia; Hotz, Thomas; Zimmermann, Armin;
Towards energy consumption prediction with safety margins for multicopter systems. - In: Proceedings of the 11th EAI International Conference on Performance Evaluation Methodologies and Tools : VALUETOOLS 2017 : 5-7 December 2017, Venice, Italy. - New York, NY, USA : ACM, ISBN 978-1-4503-6346-4, (2017), S. 227-228
Fast abstract

https://doi.org/10.1145/3150928.3150964
Glock, Matthias; Hotz, Thomas;
Constructing universal, non-asymptotic confidence sets for intrinsic means on the circle. - In: Geometric science of information : third International Conference, GSI 2017, Paris, France, November 7-9, 2017 : proceedings. - Cham : Springer International Publishing, ISBN 978-3-319-68445-1, (2017), S. 477-485

https://doi.org/10.1007/978-3-319-68445-1_56
Müller, Matthias A.; Worthmann, Karl;
On quadratic stage costs for mobile robots in model predictive control. - In: Proceedings in applied mathematics and mechanics : PAMM. - Weinheim [u.a.] : Wiley-VCH, ISSN 1617-7061, Bd. 17 (2017), 1, S. 825-826

https://doi.org/10.1002/pamm.201710380
Bergmann, Jean Pierre; Bielenin, Martin; Herzog, Roland A.; Hildebrand, Jörg; Riedel, Ilka; Schricker, Klaus; Trunk, Carsten; Worthmann, Karl;
Prevention of solidification cracking during pulsed laser beam welding. - In: Proceedings in applied mathematics and mechanics : PAMM. - Weinheim [u.a.] : Wiley-VCH, ISSN 1617-7061, Bd. 17 (2017), 1, S. 405-406

https://doi.org/10.1002/pamm.201710172
Berger, Thomas; Gernandt, Hannes; Trunk, Carsten; Winkler, Henrik; Wojtylak, Michał;
A new bound for the distance to singularity of a regular matrix pencil. - In: Proceedings in applied mathematics and mechanics : PAMM. - Weinheim [u.a.] : Wiley-VCH, ISSN 1617-7061, Bd. 17 (2017), 1, S. 863-864

https://doi.org/10.1002/pamm.201710399
Gernandt, Hannes; Krauße, Dominik; Sommer, Ralf; Trunk, Carsten;
A new method for network redesign via rank one updates. - In: Proceedings in applied mathematics and mechanics : PAMM. - Weinheim [u.a.] : Wiley-VCH, ISSN 1617-7061, Bd. 17 (2017), 1, S. 857-858

https://doi.org/10.1002/pamm.201710396
Behrndt, Jussi; Gsell, Bernhard; Schmitz, Philipp; Trunk, Carsten;
An estimate on the non-real spectrum of a singular indefinite Sturm-Liouville operator. - In: Proceedings in applied mathematics and mechanics : PAMM. - Weinheim [u.a.] : Wiley-VCH, ISSN 1617-7061, Bd. 17 (2017), 1, S. 859-860

https://doi.org/10.1002/pamm.201710397
Kubek, Mario M.; Böhme, Thomas; Unger, Herwig;
Spreading activation: a fast calculation method for text centroids. - In: Proceedings of 2017 the 3rd International Conference on Communication and Information Processing : ICCIP 2017, Tokyo, Japan, November 24-26, 2017. - New York, New York : The Association for Computing Machinery, ISBN 978-1-4503-5365-6, (2017), S. 24-27

https://doi.org/10.1145/3162957.3163014
Derkach, Vladimir; Trunk, Carsten;
Coupling of definitizable operators in Kre&bovko;in spaces. - In: Nanosistemy: fizika, chimija, matematika - Sankt-Peterburg, ISSN 22208054, Bd. 8 (2017), 2, S. 166-179

https://doi.org/10.17586/2220-8054-2017-8-2-166-179