61,397 research outputs found
Atmospheric composition affects heat- and mass-transfer processes
For environmental control system functions sensitive to atmospheric composition, components are test-operated in helium-oxygen and nitrogen-oxygen mixtures, pure oxygen, and air. Transient heat- and mass-transfer tests are conducted for carbon dioxide adsorption on molecular sieve and for water vapor adsorption on silica gel
On the Evolution, Numbers, and Characteristics of Close-Binary Supersoft Sources
The ability to perform detailed evolutionary calculations is essential to the
development of a well-defined and testable binary model. Unfortunately,
traditional evolutionary calculations cannot be used to follow a significant
fraction of possible close-binary supersoft sources (CBSSs). It is therefore
important to examine the input physics carefully, to be sure that all relevant
and potentially important physical processes are included. In this paper we
continue a line of research begun last year, and explore the role that winds
are expected to play in the evolution of CBSSs. We find that at least a subset
of the systems that seemed to be candidates for common envelope evolution may
survive, if radiation emitted by white dwarf drives winds from the system. We
study the effects of winds on the binary evolution of CBSSs, and compute the
number and characteristics of CBSSs expected to be presently active in galaxies
such as our own or M31.Comment: 13 pages; figures included in 0.33 M postscript file; in Supersoft
X-ray Sources, ed. J. Greiner (Springer-Verlag: Berlin) (1996
Development of deployable structures for large space platform systems, volume 2
Ground test article design, deployable volumes concept development, habitat and hangar conceptual designs, and deployable volumes analyses are addressed
Development of deployable structures for large space platform systems. Volume 1: Executive summary
Candidate deployable linear platform system concepts suitable for development to technology readiness by 1986 are reviewed. The systems concepts were based on trades of alternate deployable/retractable structure concepts, integration of utilities, and interface approaches for docking and assembly of payloads and subsystems. The deployable volume studies involved generation of concepts for deployable volumes which could be used as unpressurized or pressurized hangars, habitats and interconnecting tunnels. Concept generation emphasized using flexible materials and deployable truss structure technology
Development of deployable structures for large space platform systems, part 1
Eight deployable platform design objectives were established: autodeploy/retract; fully integrated utilities; configuration variability; versatile payload and subsystem interfaces; structural and packing efficiency; 1986 technology readiness; minimum EVA/RMS; and Shuttle operational compatibility
Study to investigate the effects of ionizing radiation on transistor surfaces Third quarterly report, period ending, 31 Mar. 1966
Ionizing radiation effects on transistor surface
Profits and balance sheet developments at U.S. commercial banks in 1996
U.S. commercial banks had another very good year in 1996. Profits posted strong growth, preserving the high levels of return on equity and return on assets that have prevailed over the past four years. Helping to boost profits were continued strong growth of interest-earning assets, a slight widening of the net interest margin, significant gains in noninterest income, and continued containment of noninterest expenses. Return on assets edged up despite a slight increase in provisioning for loan and lease losses relative to assets. Delinquency and charge-off rates stayed low for business loans but climbed throughout the year for consumer loans.Bank assets ; Banks and banking
Localization transitions in non-Hermitian quantum mechanics
We study the localization transitions which arise in both one and two
dimensions when quantum mechanical particles described by a random
Schr\"odinger equation are subjected to a constant imaginary vector potential.
A path-integral formulation relates the transition to flux lines depinned from
columnar defects by a transverse magnetic field in superconductors. The theory
predicts that the transverse Meissner effect is accompanied by stretched
exponential relaxation of the field into the bulk and a diverging penetration
depth at the transition.Comment: 4 pages (latex) with 3 figures (epsf) embedded in the text using the
style file epsf.st
Firm Capabilities, Competition and Industrial Policies in a History-Friendly Model of the Computer Industry
In this paper, we explore some problems that industrial policy faces in industries characterized by dynamic increasing returns on the basis of a 'history friendly model' of the evolution of the computer industry. How does policy affect industry structure over the course of industry evolution? Is the timing of the intervention important? Do policy interventions have indirect and perhaps unintended consequences on different markets at different times? We focus on two sets of policies: antitrust and interventions aiming at supporting the entry of new forms in the industry. The results of our simulations show that, if strong dynamic increasing returns are operative, both through technological capabilities and through customer tendency to stick with a brand, there is little that antitrust and entry policy could have done to avert the rise of a dominant firm in mainframes. On the other hand, if the customer lock in effect had been smaller, either by chance or through policies that discouraged efforts of firms to lock in their customers, the situation might have been somewhat different. In the first place, even in the absence of antitrust or entry encouraging policies, market concentration would have been lower, albeit a dominant firm would emerge anyhow. Second, antitrust and entry encouraging policies would have been more effective in assuring that concentration would decrease. The leading firm would continue to dominate the market, but its relative power would be reduced. © Elsevier Science B.V
Long range order in the classical kagome antiferromagnet: effective Hamiltonian approach
Following Huse and Rutenberg [Phys. Rev. B 45, 7536 (1992)], I argue the
classical Heisenberg antiferromagnet on the kagom\'e lattice has long-range
spin order of the type (modulo gradual orientation
fluctuations of the spins' plane). I start from the effective quartic
Hamiltonian for the soft (out of plane) spin fluctuation modes, and treat as a
perturbation those terms which depend on the discrete coplanar state. Soft mode
correlations, which become the coefficients of a discrete effective
Hamiltonian, are estimated analytically.Comment: 4pp, no figures. Converted to PRB format, extensive revisions/some
reorderings to improve clarity; some cut
- …