19,829 research outputs found
Analysis of nuclear waste disposal in space, phase 3. Volume 2: Technical report
The options, reference definitions and/or requirements currently envisioned for the total nuclear waste disposal in space mission are summarized. The waste form evaluation and selection process is documented along with the physical characteristics of the iron nickel-base cermet matrix chosen for disposal of commercial and defense wastes. Safety aspects of radioisotope thermal generators, the general purpose heat source, and the Lewis Research Center concept for space disposal are assessed as well as the on-pad catastrophic accident environments for the uprated space shuttle and the heavy lift launch vehicle. The radionuclides that contribute most to long-term risk of terrestrial disposal were determined and the effects of resuspension of fallout particles from an accidental release of waste material were studied. Health effects are considered. Payload breakup and rescue technology are discussed as well as expected requirements for licensing, supporting research and technology, and safety testing
Analysis of nuclear waste disposal in space, phase 3. Volume 1: Executive summary of technical report
The objectives, approach, assumptions, and limitations of a study of nuclear waste disposal in space are discussed with emphasis on the following: (1) payload characterization; (2) safety assessment; (3) health effects assessment; (4) long-term risk assessment; and (5) program planning support to NASA and DOE. Conclusions are presented for each task
Investigation of infrared phonon modes in multiferroic single-crystal FeTeOBr
Reflection and transmission as a function of temperature (5--300 K) have been
measured on single crystals of the multiferroic compound FeTeOBr
utilizing light spanning the far infrared to the visible portions of the
electromagnetic spectrum. The complex dielectric function and optical
properties were obtained via Kramers-Kronig analysis and by fits to a
Drude-Lortentz model. Analysis of the anisotropic excitation spectra via
Drude-Lorentz fitting and lattice dynamical calculations have lead to the
observation of all 52 IR-active modes predicted in the plane and 43 or the
53 modes predicted along the b axis of the monoclinic cell. Assignments to
groups (clusters) of phonons have been made and trends within them are
discussed in light of our calculated displacement patterns.Comment: 9 pages, 7 figure
Geoacoustic Inversion of Ship Radiated Noise in Shallow Water Using Data From a Single Hydrophone
The Centre for Maritime Research and Experimentation conducted a geoacoustic inverse experiment in the Mediterranean Sea in the summer of 2012. Among the objectives was to employ an autono- mous underwater vehicle to collect acoustic data to invert for properties of the seafloor. Inversion results for the compression wave speed in the bottom and the source spectrum of the R/V Alliance during a close approach to the bottom moored vehicle are presented. The estimated wave speed was 1529 m/s (r ¼ 10). The source spectrum of the Alliance was estimated across more than six octaves of frequency
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