The Greater Philadelphia Philosophy Consortium was launched in the early eighties. It began during a particularly lean period in the American economy. But its success is linked as much to the need to be in touch with the rapidly changing currents of the philosophical climate as with the need to insure an adequately stocked professional community in the Philadelphia area faced, perhaps permanently, with the threat of increasing attrition. The member schools of the Consortium now include Bryn Mawr College, the University of Pennsylvania, Temple University, and Villanova University, that is, the schools of the area that offer advanced degrees in philosophy. The philosophy faculties of these schools form the core of the Consortium, which offers graduate students the instructional and library facilities of each member school. The Consortium is also supported by the associated faculties of other regional schools that do not offer advanced degrees - notably, those at Drexel University, Haverford College, La Salle University, and Swarthmore College - both philosophers and members of other departments as well as interested and professionally qualified persons from the entire region. The affiliated and core professionals now number several hundreds, and the Consortium's various ventures have been received most enthusiastically by the academic community. At this moment, the Consortium is planning its fifth year of what it calls the Conferences on the Philosophy of the Human Studies.

19th Canadian Fracture Conference, Ottawa, Ontario, May 29-31, 1989

The understanding of time dependent crack propagation processes occupies a central place in the study of fracture. It also encompasses a wide range of conditions: failure under sustained loading in a corrosive environment, fracture under cyclic loading in non-degrading and in corrosive environment, and rupture at high temperature. This list covers probably 90% of the failures that occur in engineering practice. The process of time dependent fracture is controlled by the physics of atomic interaction changes; it is strongly influenced by the micro structure; and affected by the interaction of the material with the mechanical (load, displacement), the thermal (temperature), and the chemical or radiation environment. To be able to control crack propagation the development of testing methods and the understanding of the industrial environment is essential. The conference was organized in this context. A call was issued for contributions to the following topics. THERMAL ACTIVATION. Theoretical papers dealing with the modification of fracture mechanics to accommodate thermally activated processes. TIME DEPENDENT MICRO-PROCESSES. Presentations covering both the theoretical and observational aspects of creep and fatigue damage in materials whose microstructures may exert a significant influence on crack growth. INDUSTRIAL APPLICATIONS. Submissions describing the practical application of fracture mechanics and damage tolerance analysis to the determination of useful operating lives. x ENVIRONMENTAL EFFECTS. Papers dealing with engineering materials and/or components exposed to aggressive environments, with and without temperature effects. The response was gratifying. Leading experts responded; the organizers of the conference are grateful for the large number of excellent contributions."

Over the past few years, we have made numerous presentations, delivered several series of lectures, and participated in many discussions on the processes of time-dependent crack growth. We felt that the understanding of these processes had reached a degree of maturity: the basic physical principles were established and their application to engineering practice was now feasible. We concluded that the best way to organize this knowledge was to write it up in a single, coherent system. Martinus Nijhoff kindly encouraged us and generously offered their collaboration. Hence, this book. The physical process of time-dependent subcritical crack growth is rigorously defined by statistical mechanics. If well presented, the principles can be readily understood by practitioners of fracture research and design engineers. We present the physical processes of crack growth in terms of atomic interactions that assume only a working knowledge of the standard engineering materials course contents. From this, we develop a framework that is valid for any type of material, be it metallic, polymeric, ceramic, glass or mineral - indeed, any solid. We also assume an elementary exposure to fracture mechanics. An appendix is provided that outlines those aspects of fracture mechanics that are needed for an introduction to fracture kinetics analyses; it also provides a common ground for concepts and terminology (see Appendix A). We proceed through theory to applications that are of interest in research, development and design, as well as in test and operating engineering practice.

19th Canadian Fracture Conference, Ottawa, Ontario, May 29-31, 1989

The Greater Philadelphia Philosophy Consortium was launched in the early eighties. It began during a particularly lean period in the American economy. But its success is linked as much to the need to be in touch with the rapidly changing currents of the philosophical climate as with the need to insure an adequately stocked professional community in the Philadelphia area faced, perhaps permanently, with the threat of increasing attrition. The member schools of the Consortium now include Bryn Mawr College, the University of Pennsylvania, Temple University, and Villanova University, that is, the schools of the area that offer advanced degrees in philosophy. The philosophy faculties of these schools form the core of the Consortium, which offers graduate students the instructional and library facilities of each member school. The Consortium is also supported by the associated faculties of other regional schools that do not offer advanced degrees - notably, those at Drexel University, Haverford College, La Salle University, and Swarthmore College - both philosophers and members of other departments as well as interested and professionally qualified persons from the entire region. The affiliated and core professionals now number several hundreds, and the Consortium's various ventures have been received most enthusiastically by the academic community. At this moment, the Consortium is planning its fifth year of what it calls the Conferences on the Philosophy of the Human Studies.