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SOAR (Support Office for Aerogeophysical Research) Annual Report 1994/1995
The Support Office for Aerogeophysical Research (SOAR) was a facility of the National Science Foundation's Office of Polar Programs whose mission is to make airborne geophysical observations available to the broad research community of geology, glaciology and other sciences. The central office of the SOAR facility is located in Austin, Texas within the University of Texas Institute for Geophysics. Other institutions with significant responsibilities are the Lamont Doherty Earth Observatory of Columbia University and the Geophysics Branch of the U.S . Geological Survey. This report summarizes the goals and accomplishments of the SOAR facility during 1994/1995 and plans for the next year.National Science Foundation's Office of Polar ProgramsInstitute for Geophysic
Cosmic Chemical Evolution with an Early Population of Intermediate Mass Stars
We explore the consequences of an early population of intermediate mass stars
in the 2 - 8 M\odot range on cosmic chemical evolution. We discuss the
implications of this population as it pertains to several cosmological and
astrophysical observables. For example, some very metal-poor galactic stars
show large enhancements of carbon, typical of the C-rich ejecta of low-mass
stars but not of supernovae; moreover, halo star carbon and oxygen abundances
show wide scatter, which imply a wide range of star-formation and
nucleosynthetic histories contributed to the first generations of stars. Also,
recent analyses of the 4He abundance in metal-poor extragalactic H II regions
suggest an elevated abundance Yp \simeq 0.256 by mass, higher than the
predicted result from big bang nucleosynthesis assuming the baryon density
determined by WMAP, Yp = 0.249. Although there are large uncertainties in the
observational determination of 4He, this offset may suggest a prompt initial
enrichment of 4He in early metal-poor structures. We also discuss the effect of
intermediate mass stars on global cosmic evolution, the reionization of the
Universe, the density of white dwarfs, as well as SNII and SNIa rates at high
redshift. We also comment on the early astration of D and 7Li. We conclude that
if intermediate mass stars are to be associated with Population III stars,
their relevance is limited (primarily from observed abundance patterns) to low
mass structures involving a limited fraction of the total baryon content of the
Universe.Comment: Submitted to MNRA
Gauge drivers for the generalized harmonic Einstein equations
The generalized harmonic representation of Einstein's equations is manifestly hyperbolic for a large class of gauge conditions. Unfortunately most of the useful gauges developed over the past several decades by the numerical relativity community are incompatible with the hyperbolicity of the equations in this form. This paper presents a new method of imposing gauge conditions that preserves hyperbolicity for a much wider class of conditions, including as special cases many of the standard ones used in numerical relativity: e.g., K freezing, Gamma freezing, Bona-Massó slicing, conformal Gamma drivers, etc. Analytical and numerical results are presented which test the stability and the effectiveness of this new gauge-driver evolution system
TQM in a test environment
In response to the changing aerospace economic climate, Martin Marietta Astronautics Group (MMAG) has adopted a Total Quality Management (TQM) philosophy to maintain a competitive edge. TQM emphasizes continuous improvement of processes, motivation to improve from within, cross-functional involvement, people empowerment, customer satisfaction, and modern process control techniques. The four major initiatives of TQM are Product Excellence, Manufacturing Resource Planning (MRP II), People Empowerment, and Subcontract Management. The Defense Space and Communications (DS&C) Test Lab's definition and implementation of the MRP II and people empowerment initiatives within TQM are discussed. The application of MRP II to environmental test planning and operations processes required a new and innovative approach. In an 18 month span, the test labs implemented MRP II and people empowerment and achieved a Class 'A' operational status. This resulted in numerous benefits, both tangible and intangible, including significant cost savings and improved quality of life. A detailed description of the implementation process and results are addressed
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