MODELLING DIRECTIONAL SOLIDIFICATION Semi-annual Progress Report 1 March 1986 to 28 February 1987

摘要

This grant is a continuation of Contract NAS8-34891. The overall objective of this program is to develop an improved understanding of phenomena of importance to directional solidification, to enable explanation and prediction of differences in behavior between solidification on Earth and in space. Currently emphasis is on determining the influence of convection and freezing rate fluctuations on compositional homogeneity and crystalline perfection.nThis is a combined second and third semi-annual report, i.e. an annual report. Below is a summary of progress made this last year. Details follow.nSignificant personnel changes have occurred since the first semi-annual report one year ago. Lorraine Ruggiano resigned shortly after the last report was written to take employment in industry. In June a new student, Ross Gray, was recruited to replace her. Greg Neugebauer successfully defended his M.S. thesis on April 18, 1986 and passed his Ph.D. qualifying examination on August 15, 1986. The research proposition for his Ph.D. qualifying exam is included here as Appendix F. In January of this year a new Ph.D. student, Mohsen Banan, joined us after completing his M.S. in physics under Professor Lai at the A & M University of Alabama.