43,963 research outputs found
Studies of the effects of gravitational and inertial forces on cardiovascular and respiratory dynamics
The current status and application are described of the biplane video roentgen densitometry, videometry and video digitization systems. These techniques were developed, and continue to be developed for studies of the effects of gravitational and inertial forces on cardiovascular and respiratory dynamics in intact animals and man. Progress is reported in the field of lung dynamics and three-dimensional reconstruction of the dynamic thoracic contents from roentgen video images. It is anticipated that these data will provide added insight into the role of shape and internal spatial relationships (which is altered particularly by acceleration and position of the body) of these organs as an indication of their functional status
Thermal Properties of a Simulated Lunar Material in Air and in Vacuum
Thermal properties of simulated lunar material in air and in vacuu
Reverse engineering a spectrum: using fluorescent spectra of molecular hydrogen to recreate the missing Lyman-α line of pre-main sequence stars
The hydrogen Lyman-α (Lyα) line, a major source of ionization of metals in the circumstellar disks of pre-main sequence (PMS) stars, is usually not observed due to absorption by interstellar and circumstellar hydrogen. We have developed a technique to reconstruct the intrinsic Lyα line using the observed emission in the H2 B-X lines that are fluoresced by Lyα. We describe this technique and the subsequent analysis of the ultraviolet (UV) spectra of the TW Hya, RU Lupi and other PMS stars. We find that the reconstructed Lyα lines are indeed far brighter than any other feature in the UV spectra of these stars and therefore play an important role in the ionization and heating of the outer layers of circumstellar disks
Project management in the Apollo program Interim report
Project management in Apollo progra
Photoionisation and Heating of a Supernova Driven, Turbulent, Interstellar Medium
The Diffuse Ionised Gas (DIG) in galaxies traces photoionisation feedback
from massive stars. Through three dimensional photoionisation simulations, we
study the propagation of ionising photons, photoionisation heating and the
resulting distribution of ionised and neutral gas within snapshots of
magnetohydrodynamic simulations of a supernova driven turbulent interstellar
medium. We also investigate the impact of non-photoionisation heating on
observed optical emission line ratios. Inclusion of a heating term which scales
less steeply with electron density than photoionisation is required to produce
diagnostic emission line ratios similar to those observed with the Wisconsin
H{\alpha} Mapper. Once such heating terms have been included, we are also able
to produce temperatures similar to those inferred from observations of the DIG,
with temperatures increasing to above 15000 K at heights |z| > 1 kpc. We find
that ionising photons travel through low density regions close to the midplane
of the simulations, while travelling through diffuse low density regions at
large heights. The majority of photons travel small distances (< 100pc);
however some travel kiloparsecs and ionise the DIG.Comment: 10 pages, 13 figures, accepted to MNRA
Use of glow discharge in fluidized beds
Static charges and agglomerization of particles in a fluidized bed systems are minimized by maintaining in at least part of the bed a radio frequency glow discharge. This approach is eminently suitable for processes in which the conventional charge removing agents, i.e., moisture or conductive particle coatings, cannot be used. The technique is applied here to the disproportionation of calcium peroxide diperoxyhydrate to yield calcium superoxide, an exceptionally water and heat sensitive reaction
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