@phdthesis{Frohwerk2010,
  author    = {Frohwerk, Sascha},
  title     = {Asymmetrien in der Neuen {\"O}konomischen Geographie},
  series = {Potsdamer Schriften zur Raumwirtschaft},
  journal   = {Potsdamer Schriften zur Raumwirtschaft},
  number    = {3},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-089-2},
  issn      = {2190-8702},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-49158},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xii, 213},
  year      = {2010},
  abstract  = {Die Neue {\"O}konomische Geographie (NEG) erkl{\"a}rt Agglomerationen aus einem mikro{\"o}konomischen Totalmodell heraus. Zur Vereinfachung werden verschiedene Symmetrieannahmen get{\"a}tigt. So wird davon ausgegangen, dass die betrachteten Regionen die gleiche Gr{\"o}ße haben, die Ausgabenanteile f{\"u}r verschiedene G{\"u}tergruppen identisch sind und die Transportkosten f{\"u}r alle Industrieprodukte die selben sind. Eine Folge dieser Annahmen ist es, dass zwar erkl{\"a}rt werden kann, unter welchen Bedingungen es zur Agglomerationsbildung kommt, nicht aber wo dies geschieht. In dieser Arbeit werden drei Standardmodelle der NEG um verschiedene Asymmetrien erweitert und die Ver{\"a}nderung der Ergebnisse im Vergleich zum jeweiligen Basismodell dargestellt. Dabei wird neben der Theorie auf die Methoden der Simulation eingegangen, die sich grunds{\"a}tzlich auf andere Modelle {\"u}bertragen lassen. Darauf aufbauend wird eine asymmetrische Modellvariante auf die wirtschaftliche Entwicklung Deutschlands angewandt. So l{\"a}sst sich das Ausbleiben eines fl{\"a}chendeckenden Aufschwungs in den neuen L{\"a}ndern, die starken Wanderungsbewegungen in die alten L{\"a}nder und das dauerhafte Lohnsatzgef{\"a}lle in einem Totalmodell erkl{\"a}ren.},
  language  = {de}
}
@phdthesis{Albers2006,
  author    = {Albers, Nicole},
  title     = {On the relevance of adhesion : applications to Saturn's rings},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-10848},
  school      = {Universit{\"a}t Potsdam},
  year      = {2006},
  abstract  = {Since their discovery in 1610 by Galileo Galilei, Saturn's rings continue to fascinate both experts and amateurs. Countless numbers of icy grains in almost Keplerian orbits reveal a wealth of structures such as ringlets, voids and gaps, wakes and waves, and many more. Grains are found to increase in size with increasing radial distance to Saturn. Recently discovered "propeller" structures in the Cassini spacecraft data, provide evidence for the existence of embedded moonlets. In the wake of these findings, the discussion resumes about origin and evolution of planetary rings, and growth processes in tidal environments. In this thesis, a contact model for binary adhesive, viscoelastic collisions is developed that accounts for agglomeration as well as restitution. Collisional outcomes are crucially determined by the impact speed and masses of the collision partners and yield a maximal impact velocity at which agglomeration still occurs. Based on the latter, a self-consistent kinetic concept is proposed. The model considers all possible collisional outcomes as there are coagulation, restitution, and fragmentation. Emphasizing the evolution of the mass spectrum and furthermore concentrating on coagulation alone, a coagulation equation, including a restricted sticking probability is derived. The otherwise phenomenological Smoluchowski equation is reproduced from basic principles and denotes a limit case to the derived coagulation equation. Qualitative and quantitative analysis of the relevance of adhesion to force-free granular gases and to those under the influence of Keplerian shear is investigated. Capture probability, agglomerate stability, and the mass spectrum evolution are investigated in the context of adhesive interactions. A size dependent radial limit distance from the central planet is obtained refining the Roche criterion. Furthermore, capture probability in the presence of adhesion is generally different compared to the case of pure gravitational capture. In contrast to a Smoluchowski-type evolution of the mass spectrum, numerical simulations of the obtained coagulation equation revealed, that a transition from smaller grains to larger bodies cannot occur via a collisional cascade alone. For parameters used in this study, effective growth ceases at an average size of centimeters.},
  subject      = {Saturn<Planet>},
  language  = {en}
}