10,514 research outputs found

    Arc mapping

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    Establishing a compartment fire's area of origin when it has been burning at post-flashover conditions is a difficult process. Burn patterns traditionally used by fire investigators following post-flashover fires can be erroneous. This paper details research that explored the reliability of using the electrical wiring in a building to establish the origin of a fire. Forty two fully furnished experimental compartment fires using repetitive room configurations were used in the research and the resultant artefacts analysed with various types of microscopy. The analysis of the three-dimensional data indicated that there is a high probability that arcing damage observed on electrical conductors occurred in close proximity to the fire's area of origin. The series of experimental fires with repeated scenarios validated the reliability of using the arc fault mapping methodology during the investigation of fire scenes

    Pairwise Well-Formed Modes and Transformations

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    One of the most significant attitudinal shifts in the history of music occurred in the Renaissance, when an emerging triadic consciousness moved musicians towards a new scalar formation that placed major thirds on a par with perfect fifths. In this paper we revisit the confrontation between the two idealized scalar and modal conceptions, that of the ancient and medieval world and that of the early modern world, associated especially with Zarlino. We do this at an abstract level, in the language of algebraic combinatorics on words. In scale theory the juxtaposition is between well-formed and pairwise well-formed scales and modes, expressed in terms of Christoffel words or standard words and their conjugates, and the special Sturmian morphisms that generate them. Pairwise well-formed scales are encoded by words over a three-letter alphabet, and in our generalization we introduce special positive automorphisms of F3F3, the free group over three letters.Comment: 12 pages, 3 figures, paper presented at the MCM2017 at UNAM in Mexico City on June 27, 2017, keywords: pairwise well-formed scales and modes, well-formed scales and modes, well-formed words, Christoffel words, standard words, central words, algebraic combinatorics on words, special Sturmian morphism

    Spitzer/IRS investigation of MIPSGAL 24 microns compact bubbles

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    The MIPSGAL 24 μ\mum Galactic Plane Survey has revealed more than 400 compact-extended objects. Less than 15% of these MIPSGAL bubbles (MBs) are known and identified as evolved stars. We present Spitzer observations of 4 MBs obtained with the InfraRed Spectrograph to determine the origin of the mid-IR emission. We model the mid-IR gas lines and the dust emission to infer physical conditions within the MBs and consequently their nature. Two MBs show a dust-poor spectrum dominated by highly ionized gas lines of [\ion{O}{4}], [\ion{Ne}{3}], [\ion{Ne}{5}], [\ion{S}{3}] and [\ion{S}{4}]. We identify them as planetary nebulae with a density of a few 103 cm3^3\ \rm{cm^{-3}} and a central white dwarf of 200,000\gtrsim 200,000 K. The mid-IR emission of the two other MBs is dominated by a dust continuum and lower-excitation lines. Both of them show a central source in the near-IR (2MASS and IRAC) broadband images. The first dust-rich MB matches a Wolf-Rayet star of 60,000\sim 60,000 K at 7.5 kpc with dust components of 170\sim170 and 1750\sim1750 K. Its mass is about $10^{-3}\ \rm{M_\odot}anditsmasslossisabout and its mass loss is about 10^{-6}\ \rm{M_\odot/yr}. The second dust-rich MB has recently been suggested as a Be/B[e]/LBV candidate. The gas lines of [\ion{Fe}{2}] as well as hot continuum components (\sim300and and \sim1250K)arisefromtheinsideoftheMBwhileitsoutershellemitsacolderdustcomponent( K) arise from the inside of the MB while its outer shell emits a colder dust component (\sim75K).ThedistancetotheMBremainshighlyuncertain.Itsmassisabout K). The distance to the MB remains highly uncertain. Its mass is about 10^{-3}\ \rm{M_\odot}anditsmasslossisabout and its mass loss is about 10^{-5}\ \rm{M_\odot/yr}$.Comment: accepted for publication in Ap

    GreenCare for Children -- Measuring Environmental Hazards in the Childcare Industry

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    Presents findings from a two-year survey administered to a random sampling of childcare providers. Developed and interpreted by a diverse team of industry, technical, and educational experts

    Suppression of spin-torque in current perpendicular to the plane spin-valves by addition of Dy cap layers

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    We demonstrate that the addition of Dy capping layers in current perpendicular to the plane giant magneto-resistive spin-valves can increase the critical current density beyond which spin-torque induced instabilities are observed by about a factor of three. Current densities as high as 5e7 A/cm2 are measured provided that the electron current flows from the free to the reference layer. While Dy capped samples exhibit nonmagnetic 1/f noise, it is sufficiently small to be unimportant for read head operation at practical data rates.Comment: 13 pages (manuscript form), with 5 figures. Submitted for publicatio

    Planning for Post-War Construction

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    The AASHO Highway Research Project

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