8,522 research outputs found
An investigation of the optimization of parameters affecting the implementation of fourier transform spectroscopy at 20-500 micron from the C-141 airborne infrared observatory
A program for 20-500 micron spectroscopy from the NASA flying C141 infrared observatory is being carried out with a Michelson interferometer. The parameters affecting the performance of the instrument are studied and an optimal configuration for high performance on the C-141 aircraft is recommended. As each parameter is discussed the relative merits of the two modes of mirror motion (rapid scan or step and integrate) are presented
Regulating the Sharing Economy
In this introductory essay, we explore definitions of the ‘sharing economy’, a concept indicating both social (relational, communitarian) and economic (allocative, profit-seeking) aspects which appear to be in tension. We suggest combining the social and economic logics of the sharing economy to focus on the central features of network enabled, aggregated membership in a pool of offers and demands (for goods, services, creative expressions). This definition of the sharing economy distinguishes it from other related peer-to-peer and collaborative forms of production. Understanding the social and economic motivations for and implications of participating in the sharing economy is important to its regulation. Each of the papers in this special issue contributes to knowledge by linking the social and economic aspects of sharing economy practices to regulatory norms and mechanisms. We conclude this essay by suggesting future research to further clarify and render intelligible the sharing economy, not as a contradiction in terms but as an empirically observable realm of socio-economic activity
Memory Enhancement by a Semantically Unrelated Emotional Arousal Source Induced After Learning
It has been well established that moderate physiological or emotional arousal modulates memory. However, there is some controversy about whether the source of arousal must be semantically related to the information to be remembered. To test this idea, 35 healthy young adult participants learned a list of common nouns and afterward viewed a semantically unrelated, neutral or emotionally arousing videotape. The tape was shown after learning to prevent arousal effects on encoding or attention, instead influencing memory consolidation. Heart rate increase was significantly greater in the arousal group, and negative affect was significantly less reported in the non-arousal group after the video. The arousal group remembered significantly more words than the non-arousal group at both 30 min and 24 h delays, despite comparable group memory performance prior to the arousal manipulation. These results demonstrate that emotional arousal, even from an unrelated source, is capable of modulating memory consolidation. Potential reasons for contradictory findings in some previous studies, such as the timing of “delayed” memory tests, are discussed
Hypersonic test facility Patent
Hypersonic test facility for studying ablation in models under high pressure and high temperatur
Investigation of the properties of fiber metal acoustical materials
Fiber metal acoustic material development and testing for jet aircraft noise attenuatio
Capturing an Evolving Nebular Environment: A Petrographic and Geochemical Study of a Type A, B & C CAI
Calcium, Aluminum-rich Inclusions (CAIs) were the first formed solids in our Solar System, with mineral assemblages reflecting the first phases predicted to condense out of a hot nebular gas of Solar composition. Geochemical, textural and crystallographic information in CAIs can be used to constrain the temperature, pressure, and composition (e.g., oxygen fugacity) of the gaseous reservoir(s) from which they formed, as well as any secondary (nebular and parent body) processes they underwent. Coordinated geochemical and textural analyses provide information on nebular conditions (i.e., astrophysical environments and dynamics of nebular gas reservoirs) in which these CAIs formed. In order to better understand the evolution of nebular reservoirs at the time of CAI formation, we analyzed a Type A, B and C CAI using Electron Probe Micro-Analyzer (EPMA) and Electron BackScatter Diffraction (EBSD) at NASA Johnson Space Center (JSC)
Ferromagnetism in the Mott insulator Ba2NaOsO6
Results are presented of single crystal structural, thermodynamic, and
reflectivity measurements of the double-perovskite Ba2NaOsO6. These
characterize the material as a 5d^1 ferromagnetic Mott insulator with an
ordered moment of ~0.2 Bohr magnetons per formula unit and TC = 6.8(3) K. The
magnetic entropy associated with this phase transition is close to Rln2,
indicating that the quartet groundstate anticipated from consideration of the
crystal structure is split, consistent with a scenario in which the
ferromagnetism is associated with orbital ordering.Comment: 5 pages, 5 figures, added reference
A neutron scattering study of the interplay between structure and magnetism in Ba(FeCo)As
Single crystal neutron diffraction is used to investigate the magnetic and
structural phase diagram of the electron doped superconductor
Ba(FeCo)As. Heat capacity and resistivity measurements have
demonstrated that Co doping this system splits the combined antiferromagnetic
and structural transition present in BaFeAs into two distinct
transitions. For =0.025, we find that the upper transition is between the
high-temperature tetragonal and low-temperature orthorhombic structures with
( K) and the antiferromagnetic transition occurs at
K. We find that doping rapidly suppresses the
antiferromagnetism, with antiferromagnetic order disappearing at . However, there is a region of co-existence of antiferromagnetism and
superconductivity. The effect of the antiferromagnetic transition can be seen
in the temperature dependence of the structural Bragg peaks from both neutron
scattering and x-ray diffraction. We infer from this that there is strong
coupling between the antiferromagnetism and the crystal lattice
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