4 research outputs found
Applications of CFD and visualization techniques
In this paper, three applications are presented to illustrate current techniques for flow calculation and visualization. The first two applications use a commercial computational fluid dynamics (CFD) code, FLUENT, performed on a Cray Y-MP. The results are animated with the aid of data visualization software, apE. The third application simulates a particulate deposition pattern using techniques inspired by developments in nonlinear dynamical systems. These computations were performed on personal computers
Leptonic and Semileptonic Decays of Charm and Bottom Hadrons
We review the experimental measurements and theoretical descriptions of
leptonic and semileptonic decays of particles containing a single heavy quark,
either charm or bottom. Measurements of bottom semileptonic decays are used to
determine the magnitudes of two fundamental parameters of the standard model,
the Cabibbo-Kobayashi-Maskawa matrix elements and . These
parameters are connected with the physics of quark flavor and mass, and they
have important implications for the breakdown of CP symmetry. To extract
precise values of and from measurements, however,
requires a good understanding of the decay dynamics. Measurements of both charm
and bottom decay distributions provide information on the interactions
governing these processes. The underlying weak transition in each case is
relatively simple, but the strong interactions that bind the quarks into
hadrons introduce complications. We also discuss new theoretical approaches,
especially heavy-quark effective theory and lattice QCD, which are providing
insights and predictions now being tested by experiment. An international
effort at many laboratories will rapidly advance knowledge of this physics
during the next decade.Comment: This review article will be published in Reviews of Modern Physics in
the fall, 1995. This file contains only the abstract and the table of
contents. The full 168-page document including 47 figures is available at
http://charm.physics.ucsb.edu/papers/slrevtex.p
The Spread of Exotic Plant Species at Mount St. Helens: The Roles of a Road, Disturbance Type, and Post-disturbance Management
Mount St. Helens and the surrounding landscape were dramatically altered during and after the 18 May 1980 eruption, creating large expanses of disturbed land that could be susceptible to exotic plant invasion. We studied spatial patterns of exotic plant richness and abundance along a road and pedestrian trail that traverse a volcanic disturbance gradient with varying management prescriptions. In blast areas, exotic plant richness and abundance increased near the road, demonstrating the role that both roads and canopy cover play in the dispersal and establishment of exotic species. However, the overall richness and abundance of exotic plants were relatively low, and the pyroclastic-flow zone vegetation was dominated by native plants