2,246 research outputs found
Investigation of natural environment by space means. Geobotany, Geomorphology, soil sciences, agricultural lands, landscape study
Reports given by Soviet specialists at a meeting of Socialist countries on remote sensing of the earth using aerospace methods are presented
The Effect of Symmetry Lowering on the Dielectric Response of
We use first-principles density functional theory calculations to investigate
the dielectric response of BaZrO perovskite. A previous study [Arkbarzadeh
{\em et al.} Phys. Rev. B {\bf 72}, 205104 (2005)] reported a disagreement
between experimental and theoretical low temperature dielectric constant
for the high symmetry BaZrO structure. We show that a fully
relaxed 40-atom BaZrO structure exhibits O octahedral tilting, and
that agrees with experiment. The change in from
high-symmetry to low-symmetry structure is due to increased phonon frequencies
as well as decreased mode effective charges.Comment: 4 pages, 2 figure
Degradation and reuse of radiative thermal protection system materials for the space shuttle
Three silicide coated columbium alloys and two cobalt alloys were subjected to identical simulated reentry profiling exposures in both static (controlled vacuum leak) and dynamic (hypersonic plasma shear) environments. Primary emphasis in the columbium alloy evaluation was on the Cb752 and C129Y alloys with a lesser amount on FS85. Commercial silicide coatings of the R512E and VH109 formulations were used. The coated specimens were intentionally defected to provide the types of coating flaws that are expected in service. Temperatures were profiled up to peak temperatures of either 2350 F or 2500 F for 15 minutes in each cycle
Variability in high-mass X-ray binaries
Strongly magnetized, accreting neutron stars show periodic and aperiodic
variability over a wide range of time scales. By obtaining spectral and timing
information on these different time scales, we can have a closer look into the
physics of accretion close to the neutron star and the properties of the
accreted material. One of the most prominent time scales is the strong
pulsation, i.e., the rotation period of the neutron star itself. Over one
rotation, our view of the accretion column and the X-ray producing region
changes significantly. This allows us to sample different physical conditions
within the column but at the same time requires that we have
viewing-angle-resolved models to properly describe them. In wind-fed high-mass
X-ray binaries, the main source of aperiodic variability is the clumpy stellar
wind, which leads to changes in the accretion rate (i.e., luminosity) as well
as absorption column. This variability allows us to study the behavior of the
accretion column as a function of luminosity, as well as to investigate the
structure and physical properties of the wind, which we can compare to winds in
isolated stars.Comment: 6 pages, 4 figures, accepted for publication in Astronomische
Nachrichten (proceedings of the XMM-Newton Workshop 2019
Targeted drug delivery of near IR fluorescent doxorubicin-conjugated poly(ethylene glycol) bisphosphonate nanoparticles for diagnosis and therapy of primary and metastatic bone cancer in a mouse model
Using {\sc top-c} for Commodity Parallel Computing in Cosmic Ray Physics Simulations
{\sc top-c} (Task Oriented Parallel C) is a freely available package for
parallel computing. It is designed to be easy to learn and to have good
tolerance for the high latencies that are common in commodity networks of
computers. It has been successfully used in a wide range of examples, providing
linear speedup with the number of computers. A brief overview of {\sc top-c} is
provided, along with recent experience with cosmic ray physics simulations.Comment: Talk to be presented at the XI International Symposium on Very High
Energy Cosmic Ray Interaction
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