1,783 research outputs found

    Mechanism and kinetics of aging in Inconel 718

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    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

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    Galactic dust emission is polarized at unexpectedly high levels, as revealed by Planck. The origin of the observed ≃20%\simeq 20\% 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 ≃20\simeq 20%. 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 [pV/E(B−V)]max=9\left[p_V/E\left(B-V\right)\right]_{\rm max} = 9%mag−1^{-1} and is at least as high as 13%mag−1^{-1} 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

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    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

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    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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