4,261 research outputs found

    A full-scale fire program to evaluate new furnishings and textile materials developed by the National Aeronautics and Space Administration

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    A program of experimental fires was carried out to establish the advantages offered by new materials for improved fire safety. Four full-scale bedrooms, differing only in the materials used to furnish them, were built and burned to provide comparative data on the fire hazards produced. Cost and availability differences were not considered. The visual evidence provided by TV and photographic coverage of the four experimental room fires showed clearly that the rooms responded very differently to a common ignition condition. Resistance to the ignition and spread of fire was substantially improved in the rooms furnished completely or partially with the new materials

    The 'War on Poverty' after 40 Years: A Minskyan Assessment

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    Hyman Minsky is best known for his work in the area of financial economics, and especially for his financial instability hypothesis. In recent years, some authors have also recognized his advocacy of the “employer of last resort” as part of his “big government” intervention to help maintain stability. However, very little research has been undertaken regarding Minsky’s early involvement in the “War on Poverty.” This paper will trace the development of Minsky’s thinking on antipoverty policies to his support for welfare reform and federal job creation programsWar on Poverty, employer of last resort, anti-poverty programs, Hyman Minsky, unemployment, job creation, welfare, economic opportunity, Keynesian policy, demand stimulus, full employment, structuralist

    Single-Dirac-Cone topological surface states in TlBiSe2 class of Topological Insulators

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    We have investigated several strong spin-orbit coupling ternary chalcogenides related to the (Pb,Sn)Te series of compounds. Our first-principles calculations predict the low temperature rhombohedral ordered phase in TlBiTe2, TlBiSe2, and TlSbX2 (X=Te, Se, S) to be topologically Kane-Mele Z2 = -1 nontrivial. We identify the specific surface termination that realizes the single Dirac cone through first-principles surface state computations. This termination minimizes effects of dangling bonds making it favorable for photoemission (ARPES) experiments. Our analysis predicts that thin films of these materials would harbor novel 2D quantum spin Hall states, and support odd-parity topological superconductivity. For a related work also see arXiv:1003.2615v1. Experimental ARPES results will be published elsewhere.Comment: Accepted for publication in Phys. Rev. Lett. (2010). Submitted March 201

    Can Euroland survive?

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    Social unrest across Europe is growing as Euroland's economy collapses faster than the United States', the result of falling exports and a weaker fiscal response. The controversial title of this brief is based on a belief that the nature of the euro itself limits Euroland's fiscal policy space. The nations that have adopted the euro face market-imposed fiscal constraints on borrowing because they are not sovereign countries. Research Associate Stephanie A. Kelton and Senior Scholar L. Randall Wray foresee a real danger that these nations will be unable to prevent an accelerating slide toward depression that will threaten the existence of the European Union

    Early Form Based Morphological Decomposition in Tagalog: MEG Evidence from Reduplication, Infixation and Circumfixation

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    Neuro-and psycholinguistic experimentation supports the early decomposition of morphologically complex words within the ventral processing stream, which MEG has localized to the M170 response in the (left) visual word form area ( VWFA). Decomposition into an exhaustive parse of visual morpheme forms extends beyond words like farmer to those imitating complexity (e.g., brother; Lewis et al., 2011), and to “unique” stems occurring in only one word but following the syntax and semantics of their affix (e.g., vulnerable; Gwilliams & Marantz, 2018). Evidence comes primarily from suffixation; other morphological processes have been under-investigated. This study explores circumfixation, infixation, and reduplication in Tagalog. In addition to investigating whether these are parsed like suffixation, we address an outstanding question concerning semantically empty morphemes. Some words in Tagalog resemble English winter as decomposition is not supported (wint-er); these apparently reduplicated pseudoreduplicates lack the syntactic and semantic features of reduplicated forms. However, unlike winter, these words exhibit phonological behavior predicted only if they involve a reduplicating morpheme. If these are decomposed, this provides evidence that words are analyzed as complex, like English vulnerable, when the grammar demands it. In a lexical decision task with MEG, we find that VWFA activity correlates with stem:word transition probability for circumfixed, infixed, and reduplicated words. Furthermore, a Bayesian analysis suggests that pseudoreduplicates with reduplicate-like phonology are also decomposed; other pseudoreduplicates are not. These findings are consistent with an interpretation that decomposition is modulated by phonology in addition to syntax and semantics

    Charge collective modes in an incommensurately modulated cuprate

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    We report the first measurement of collective charge modes of insulating Sr14Cu24O41 using inelastic resonant x-ray scattering over the complete Brillouin zone. Our results show that the intense excitation modes at the charge gap edge predominantly originate from the ladder-containing planar substructures. The observed ladder modes (E vs. Q) are found to be dispersive for momentum transfers along the "legs" but nearly localized along the "rungs". Dispersion and peakwidth characteristics are similar to the charge spectrum of 1D Mott insulators, and we show that our results can be understood in the strong coupling limit (U >> t_{ladder}> t_{chain}). The observed behavior is in marked contrast to the charge spectrum seen in most two dimensional cuprates. Quite generally, our results also show that momentum-tunability of inelastic scattering can be used to resolve mode contributions in multi-component incommensurate systems.Comment: 4+ pages, 5 figure

    A Full-Scale Fire Program to Evaluate New Furnishings and Textile Materials Developed by the National Aeronautics and Space Administration

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    The plans for the present series of full-scale experimental fires were initiated at the suggestion of NASA following the presentation of a film and discussion illustrating Battelle-Columbus' recent work in fire research. That film showed bedroom-type fires carried out as a part of a program to determine the influence of the cyclic characteristics of real fires under limited ventilation on the burning and pyrolysis properties of the room furnishings. A new series of fires was suggested by NASA designed to show the performance of new fire resistant and fire retardant materials by providing comparative fire and smoldering environmental conditions. More recently, the goal for the new series of fires was written in a meeting with NASA personnel and others at Battelle on May 3 and 4, 1972. The goal was as follows: To establish the need for special materials of improved fire safety in domiciliary settings of public concern, and to assess, in a professionally acceptable manner, the potential of materials arising from the new space-age technology for this purpose. It was anticipated that some new materials arising from the space-age technology and not yet available through conventional commercial channels might provide significant improvements in fire safety if the best of the commercially available materials showed important shortcomings in this area. It was the intent of this program to assess the benefits that could accrue from the use of these new materials. Fire safety is a matter requiring the evaluation of a number of factors. For example, fire resistance and fire spread, visibility during the fire, toxicity of evolved gases, and the fire-fighting problem that is created must be evaluated before the relative hazard can be assessed. The plan of the program provided for sampling and instrumentation to evaluate these factors, consistent with the goal of technological utilization that has been specified. Arrangements were made with the Columbus Fire Department to use an existing six-story concrete building', designed and used as a fire training tower, as the site for the experimental fires. The visual evidence provided by TV and photographic coverage of the four experimental room fires showed clearly that the rooms responded very differently to a common ignition condition. In particular: (1) The Typical room, furnished from conventional retail sources, ignited easily and burned rapidly so that after 8 minutes the contents of the room were nearly destroyed. (2) The Improved room, furnished with materials selected as being among the best commercially available, showed substantial improvement over the Typical room in that there was slower fire spread. However, the relatively complete destruction of the room contents that resulted, and the large amounts of smoke, made it clear that substantial further improvements were needed. This fire was stopped after 29 minutes. (3) The Space-age room, furnished completely with new materials that were not yet commercially available, did not ignite under the common ignition condition and soon demonstrated the substantial improvement in fire resistance available for those components close to the ignition source. A second and larger ignition arrangement showed that this room can burn, but the difficulty with which this was brought about confirmed the improved fire resistance available with use of these materials. (4) The Mixed room ensemble, furnished with 'materials identical to the Typical room except for the substitution of the bed from the Space-age room, illustrated the improvement in control of fire spread available by careful placement of fire materials in the important paths of fire development of an otherwise ordinary room. The most significant hazards at early times in each fire were due to the rapid rise in heat flux and the abrupt obscuration of vision by smoke. The most consistent toxicity hazard was due to CO and its importance would depend on the ability of the occupant to survive the initial heat and smoke menace which characterized each fire room. Other gases and vapors were shown to reach hazardous levels in certain fire rooms and, again, their significance to an occupant, would relate to the times in which such hazards occurred, and probably to the synergistic nature of the hazard arising from mixtures of such gases. Fire retardant items in the room are caused to pyrolyze by the heat of burning from other items in the room and so contribute to combustible and toxic vapor accumulations, even though they may not have entered into the burning process. This effect of a mixture of combustible materials to produce burning and pyrolysis not characteristic of any one item individually we have chosen to call the "ensemble effect". Further full-scale fire trials may be expected to show the significant changes that control the burning and pyrolytic processes and in that event a programmed fire chamber should be developed to yield realistic laboratory results

    Chemically gated electronic structure of a superconducting doped topological insulator system

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    Angle resolved photoemission spectroscopy is used to observe changes in the electronic structure of bulk-doped topological insulator Cux_xBi2_2Se3_3 as additional copper atoms are deposited onto the cleaved crystal surface. Carrier density and surface-normal electrical field strength near the crystal surface are estimated to consider the effect of chemical surface gating on atypical superconducting properties associated with topological insulator order, such as the dynamics of theoretically predicted Majorana Fermion vortices
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