1,793 research outputs found
Mechanism and kinetics of aging in Inconel 718
Age hardening in Inconel 718 is investigated using Brinell hardness measurements. Formation of a precipitate causes an increase in hardness
Extreme Starlight Polarization in a Region with Highly Polarized Dust Emission
Galactic dust emission is polarized at unexpectedly high levels, as revealed
by Planck. The origin of the observed polarization fractions can
be identified by characterizing the properties of optical starlight
polarization in a region with maximally polarized dust emission. We measure the
R-band linear polarization of 22 stars in a region with a submillimeter
polarization fraction of . A subset of 6 stars is also measured in
the B, V and I bands to investigate the wavelength dependence of polarization.
We find that starlight is polarized at correspondingly high levels. Through
multiband polarimetry we find that the high polarization fractions are unlikely
to arise from unusual dust properties, such as enhanced grain alignment.
Instead, a favorable magnetic field geometry is the most likely explanation,
and is supported by observational probes of the magnetic field morphology. The
observed starlight polarization exceeds the classical upper limit of
%mag and is at least
as high as 13%mag that was inferred from a joint analysis of Planck
data, starlight polarization and reddening measurements. Thus, we confirm that
the intrinsic polarizing ability of dust grains at optical wavelengths has long
been underestimated.Comment: Accepted by A&AL, data to appear on CDS after publication. 6 page
Retrieval Guide: Kentucky Soils Data System
The Kentucky Soils Data System is an extensive data file of the physical properties and characteristics of soils as determined by field and laboratory testing. Site locations are available for most samples. Since Kentucky has been mapped geologically (scale 1:24,000), the bedrock at each of these sample locations can be determined, providing better opportunities for studying soil-bedrock (parent material) relationships. A complimentary report covers data input. This report is divided into two sections: data availability and data retrieval. The first section is designed to show the quantity and types of data available and how the data are distributed geographically. The second section consists of example problems showing how the data may be retrieved in the form of various lists or tables
Characterization of Alkali Metal Dispensers and Non-Evaporable Getter Pumps in Ultra-High Vacuum Systems for Cold Atomic Sensors
A glass ultrahigh vacuum chamber with rubidium alkali metal dispensers and
non-evaporable getter pumps has been developed and used to create a cold atomic
sample in a chamber that operates with only passive vacuum pumps. The ion-mass
spectrum of evaporated gases from the alkali metal dispenser has been recorded
as a function of dispenser current. The efficacy of the non-evaporable getter
pumps in promoting and maintaining vacuum has been characterized by observation
of the Rb vapor optical absorption on the D2 transition at 780 nm and vacuum
chamber pressure rate of rise tests. We have demonstrated a sample of
laser-cooled Rb atoms in this chamber when isolated and operating without
active vacuum pumps
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