Since the 'Introduction' to the main text gives an account of the way in which the problems treated in the following pages originated, this 'Preface' may be limited to an acknowledgement of the support the work has received. It started during the pe riod when I was professor of aero- and hydrodynamics at the Technical University in Delft, Netherlands, and many discussions with colleagues ha ve in: fluenced its devel opment. Oftheir names I mention here only that ofH. A. Kramers. Papers No. 1-13 ofthe list given at the end ofthe text were written during that period. Severa ofthese were attempts to explore ideas which later had to be abandoned, but gradually a line of thought emerged which promised more definite results. This line began to come to the foreground in pa per No. 3 (1939}, while a preliminary formulation ofthe results was given in paper No. 12 (1954}. At that time, however, there still was missing a practica method for manipulating a certain distribution function of central interest. A six months stay at the Hydrodynamics Laboratories ofthe California Institute of Technology, Pasadena, California (1950-1951}, was supported by a Contract with the Department of the Air F orce, N o. AF 33(038}-17207. A course of lectures was given during this period, which were published in typescript under the title 'On Turbulent Fluid Motion', as Report No. E-34. 1, July 1951, of the Hydrodynamics Laboratory."

This volume presents an overview of recent developments in the thermal management of electronic systems. This is increasingly recognized as an important factor in current design methodology. The topics covered include thermal management in general, thermally induced failure, numerical and experimental analysis of systems at various packaging levels, channels and electronic components, measurement techniques, liquid cooling, thermal characterization, thermal stress and die attach defects. This text is suitable for research and development engineers and scientists whose work involves the design and manufacture of electronic systems.

Since the 'Introduction' to the main text gives an account of the way in which the problems treated in the following pages originated, this 'Preface' may be limited to an acknowledgement of the support the work has received. It started during the pe riod when I was professor of aero- and hydrodynamics at the Technical University in Delft, Netherlands, and many discussions with colleagues ha ve in: fluenced its devel opment. Oftheir names I mention here only that ofH. A. Kramers. Papers No. 1-13 ofthe list given at the end ofthe text were written during that period. Severa ofthese were attempts to explore ideas which later had to be abandoned, but gradually a line of thought emerged which promised more definite results. This line began to come to the foreground in pa per No. 3 (1939}, while a preliminary formulation ofthe results was given in paper No. 12 (1954}. At that time, however, there still was missing a practica method for manipulating a certain distribution function of central interest. A six months stay at the Hydrodynamics Laboratories ofthe California Institute of Technology, Pasadena, California (1950-1951}, was supported by a Contract with the Department of the Air F orce, N o. AF 33(038}-17207. A course of lectures was given during this period, which were published in typescript under the title 'On Turbulent Fluid Motion', as Report No. E-34. 1, July 1951, of the Hydrodynamics Laboratory."

Die Hydro- und Aerodynamik hat in den letzten Jahrzehnten eine Entwicklung angenommen, welche insbesondere dadurch gekenn zeichnet ist, dass die uberzeugung von der Brauchbarkeit der mathe matischen Methoden zur Klarung physikalisch und technisch wichtiger Probleme stark gehoben wurde. Es wurde dies einerseits dadurch erreicht, dass man die an und fur sich bekannte Lehre von der Be wegung idealer Flussigkeiten, die Lehre von Wirbeln und Wirhel bewegungen im einzelnen auf die praktischen Aufgaben anzuwenden versuchte, andererseits aber den Versuch unternahm, in das schwierige und undankbare Gebiet der reibenden Flussigkeiten mit feineren mathematischen Methoden einzudringen. Wahrend der Jahre des grossen Krieges hat das Interesse an flugtechnischen Problemen die Aufmerksamkeit in allen Landern in erhohtem Masse auf die Fortschritte der theoretischen Aero- und Hydromechanik gelenkt, ohne dass die Vertreter dieser Disziplinen Gelegenheit gehabt hatten, sich auszusprechen und ihre Ergebnisse zu vergleichen. Aus diesem Grunde fassten die Unterzeichneten den Gedanken, eine Art zwangloser Zusammenkunft der Vertreter der Hydro- und Aeromechanik anzuregen. Die Zusammenkunft kam im September 1922 in Innsbruck zustande. Die Beitrage - erganzt mit einigen spater eingelaufenen Mitteilungen von einigen Herren, die verhindert waren, an der Zusammenkunft teilzunehmen - sind in dem vorliegenden Bande niedergelegt."