2,454 research outputs found
Gas cavity reactor simulation experiment final report
Gaseous cavitation reactor simulation experiment using uranium fluoride fue
Cavity reactor critical experiment, volume 4 (waves and control methods)
Fuel wave formation and control in coaxial flowing gas cavity reactor for space nuclear propulsio
Flowing gas, non-nuclear experiments on the gas core reactor
Flow tests were conducted on models of the gas core (cavity) reactor. Variations in cavity wall and injection configurations were aimed at establishing flow patterns that give a maximum of the nuclear criticality eigenvalue. Correlation with the nuclear effect was made using multigroup diffusion theory normalized by previous benchmark critical experiments. Air was used to simulate the hydrogen propellant in the flow tests, and smoked air, argon, or freon to simulate the central nuclear fuel gas. All tests were run in the down-firing direction so that gravitational effects simulated the acceleration effect of a rocket. Results show that acceptable flow patterns with high volume fraction for the simulated nuclear fuel gas and high flow rate ratios of propellant to fuel can be obtained. Using a point injector for the fuel, good flow patterns are obtained by directing the outer gas at high velocity along the cavity wall, using louvered or oblique-angle-honeycomb injection schemes
Feasibility study of full-reactor gas core demonstration test
Separate studies of nuclear criticality, flow patterns, and thermodynamics for the gas core reactor concept have all given positive indications of its feasibility. However, before serious design for a full scale gas core application can be made, feasibility must be shown for operation with full interaction of the nuclear, thermal, and hydraulic effects. A minimum sized, and hence minimum expense, test arrangement is considered for a full gas core configuration. It is shown that the hydrogen coolant scattering effects dominate the nuclear considerations at elevated temperatures. A cavity diameter of somewhat larger than 4 ft (122 cm) will be needed if temperatures high enough to vaporize uranium are to be achieved
What Fraction of the Young Clusters in the Antennae Galaxies are "Missing"?
A reexamination of the correspondence between 6 cm radio continuum sources
and young star clusters in the Antennae galaxies indicates that 85 % of the
strong thermal sources have optical counterparts, once the optical image is
shifted 1.2 arcsec to the southwest. A sample of 37 radio-optical matches are
studied in detail showing correlations between radio properties and a variety
of optical characteristics. There is a strong correlation between the radio
flux and the intrinsic optical brightness. In particular, the brightest radio
source is also the intrinsically brightest optical cluster (WS80). It is also
the most extincted cluster in the sample, the strongest CO source and the
strongest 15 micron source . Furthermore, the brightest ten radio sources are
all amongst the youngest clusters with ages in the range 0 - 4 Myr and
extinctions from A_V = 0.5 to 7.6 mag (with a median value of 2.6 mag). Only a
few of the very red clusters originally discovered by Whitmore & Schweizer are
radio sources, contrary to earlier suggestions. Finally, a new hybrid method of
determining cluster ages has been developed using both UBVI colors and H_alpha
equivalent widths to break the age-reddening degeneracy.Comment: 51 pages, 13 postscript figures, LaTex. To appear in the Astronomical
Journal, 124, 2002, Septembe
Cavity Reactor Engineering Mockup Critical Experiment
Critical mass of uranium 235 for stainless steel lined cavities in nuclear research and test reactors with heavy water reflecto
Primordial magnetic fields and nonlinear electrodynamics
The creation of large scale magnetic fields is studied in an inflationary
universe where electrodynamics is assumed to be nonlinear. After inflation ends
electrodynamics becomes linear and thus the description of reheating and the
subsequent radiation dominated stage are unaltered. The nonlinear regime of
electrodynamics is described by lagrangians having a power law dependence on
one of the invariants of the electromagnetic field. It is found that there is a
range of parameters for which primordial magnetic fields of cosmologically
interesting strengths can be created.Comment: 21 pages, 3 figure
Can be gravitational waves markers for an extra-dimension?
The main issue of the present letter is to fix specific features (which turn
out being independent of extradimension size) of gravitational waves generated
before a dimensional compactification process. Valuable is the possibility to
detect our prediction from gravitational wave experiment without high energy
laboratory investigation. In particular we show how gravitational waves can
bring information on the number of Universe dimensions. Within the framework of
Kaluza-Klein hypotheses, a different morphology arises between waves generated
before than the compactification process settled down and ordinary
4-dimensional waves. In the former case the scalar and tensor degrees of
freedom can not be resolved. As a consequence if were detected gravitational
waves having the feature here predicted (anomalous polarization amplitudes),
then they would be reliable markers for the existence of an extra dimension.Comment: 5 pages, two figure, to appear on Int. Journ. Mod. Phys.
The Geoff Egan Memorial Lecture 2011. Artefacts, art and artifice: reconsidering iconographic sources for archaeological objects in early modern Europe
A first systematic analysis of historic domestic material culture depicted in contemporaneous Western painting and prints, c.1400-1800. Drawing on an extensive data set, the paper proposes to methodologies and hermeneutics for historical analysis and archaeological correspondence
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