In the past few years, a considerable number of immigrants have established their own businesses. In doing so, they have contributed in many ways to the economic development of American and European metropolitan areas. Some businesses have been incorporated into the mainstream, while others have stayed on the economic fringes and got engaged in the informal economy. The starting point of this book is that a proper understanding of these businesses is served by focusing on the embeddedness of immigrant businesses in their economic, politico institutional and social environments from a multi disciplinary perspective rather than confining the attention to ethnic cultural or economic sociological aspects only.

This special volume contains several articles written in honour of Professor IngolfTeipel on the occasion of his 65th birthday. Professor Teipel was born on March 15th, 1933 in Wissen/Sieg. He started his school career in Betzdorf/Sieg. From 1943 to 1951 he went to the Gymnasium in Betzdorf, where he obtained his school-leaving exam after only 8 years. In 1951 Professor Teipel started his studies in Mechanical Engineering at the Technical University of Aachen and got his diploma at the Aerodynamic Institute in 1956. Then Professor Teipel decided to join the research group of the Institute of Theoretical Gasdynamics at the Deutsche Versuchsanstalt fiir Luft und Raumfahrt (DVL), the famous institute of Professor Oswatitsch, where he spent about 13 years until 1968. At the Technical University of Aachen he finished his dissertation devoted to spherical-symmetric shock waves and he obtained his doctorate in Mechanical Engineering in 1960. Some years later he went as a guest scientist to the Aerospace Laboratories of Dayton, Ohio, USA. In 1965 Professor Teipel fmished his habilitation work with a paper on unsteady transonic pressure forces at the Technical University of Aachen, where he recieved the venia legendi in fluid mechanics. In this year, Professor Teipel was given the freedom of the state Tennessee, USA."

Substantial progress has been made in the field of fluid mechanics under compensated gravity effects (microgravity). The main task of this disciplinehas evolved tremendously. Starting out with the aim of providing assistance in describing flow problems in other microgravity sciences, microgravityfluid mechanics has itself now become acknowledge as a powerful means of research. The IUTAM Symposium on Microgravity Fluid Mechanics has pro- vided the long-awaited forum for scientists from 15 coun- tries to discuss and concretize the "state-of-the-art" in this discipline. The main themes treated are: Interface Phe- nomena, Convective Processes; Marangoni effects, Solidifica- tion, Combustion, Physico-Chemical Processes, Multiphase Phenomena, Residual Acceleration effects, Fluid Handling and Non-Newtonian Flows.

Die Peristaltik zahlt zu dem jUngsten Zweig des Gesamtkomplexes der Durch- stromung physiologischer GefaBe. Sowohl in der Biomechanik als auch in der Physiologie sind diesbezUglich umfangreiche Untersuchungen innerhalb der letzten fUnfzehn Jahre durchgefUhrt worden. Insbesondere wurde versucht, eine peristaltische Stromung im Experiment und als mathematisch- physika- lisches Modell nachzubilden. Speziell in letzter Zeit sind umfangreiche experimentelle und zahlreiche theoretische Arbeiten veroffentlicht worden, wobei es auBerst schwierig und aufwendig ist, das Problem in voller All- gemeinheit zu erfassen. Deshalb mUssen in den meisten Fallen Vereinfachungen getroffen werden, urn den Aufwand fUr die experimentellen und theoretischen Untersuchungen nicht zu groB werden zu lassen. Bisher scheint noch keine Veroffentlichung bekannt zu sein, die den Themen- kreis Peristaltik in Ubersichtlicher Form darste11t. Mit diesem Buch soll versucht werden, diese LUcke zu sch1ieBen. Es 5011 eine Obersicht vermit- teln bezUg1ich 1. der Beschreibung des Phanomens Peristaltik 2. des Auftretens der Peristaltik in der Physiologie 3. der experimente11en Untersuchungen in der Physiologie 4. der Nachbildung einer perista1tischen Stromung im Experiment 5. der theoretischen Mode11e zur Peristaltik 6. der Grundgleichungen derStromungs- und Elastomechanik 7. der Losungsmethoden der entsprechenden Gleichungen. In einem umfangreichen Literaturverzeichnis sind entsprechende Arbeiten, bzw. Aufsatze Uber die oben aufgefUhrten Punkte zu finden. Die einzelnen Kapite1 sind absichtlich re1ativ kurz geha1ten, da auf die entsprechende VI Literatur verwiesen werden kann. Die vorliegende Arbeit entstand am Institut fUr Mechanik (Prof. Dr.-lng.