15,640 research outputs found

    Legal Aspects of Low-Rent Housing in New York

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    Environmental test planning, selection and standardization aids available

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    Requirements for instrumentation, equipment, and methods to be used in conducting environmental tests on components intended for use by a wide variety of technical personnel of different educational backgrounds, experience, and interests is announced

    Investigation of electrochemistry of high energy compounds in organic electrolytes Third progress report, Nov. 1, 1965 - Apr. 30, 1966

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    Electrochemical properties, and chemical reactions between cyclic esters and certain metal

    Investigation of electrochemistry of high energy compounds in organic electrolytes, May 1 - October 31, 1965

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    High energy compounds in organic electrolytes - electrochemical and chemical properties of cyclic esters, gamma butyrolactone, gamma valerolactone, and propylene carbonat

    Study of aerodynamic technology for single-cruise-engine VSTOL fighter/attack aircraft, phase 1

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    A conceptual design and analysis on a single engine VSTOL fighter/attack aircraft is completed. The aircraft combines a NASA/deHavilland ejector with vectored thrust and is capable of accomplishing the mission and point performance of type Specification 169, and a flight demonstrator could be built with an existing F101/DFE engine. The aerodynamic, aero/propulsive, and propulsive uncertainties are identified, and a wind tunnel program is proposed to address those uncertainties associated with wing borne flight

    Velocity Evolution and the Intrinsic Color of Type Ia Supernovae

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    To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, based primarily on data from the CfA Supernova Program, we examine how the velocity evolution and line strengths of Si II 6355 and Ca II H&K are related to the B-V color at peak brightness. We find that the maximum-light velocity of Si II 6355 and Ca II H&K and the maximum-light pseudo-equivalent width of Si II 6355 are correlated with intrinsic color, with intrinsic color having a linear relation with the Si II 6355 measurements. Ca II H&K does not have a linear relation with intrinsic color, but lower-velocity SNe tend to be intrinsically bluer. Combining the spectroscopic measurements does not improve intrinsic color inference. The intrinsic color scatter is larger for higher-velocity SNe Ia --- even after removing a linear trend with velocity --- indicating that lower-velocity SNe Ia are more "standard crayons." Employing information derived from SN Ia spectra has the potential to improve the measurements of extragalactic distances and the cosmological properties inferred from them.Comment: 23 pages, 21 figures, accepted by ApJ; data presented in the paper can be obtained at https://www.cfa.harvard.edu/~rfoley/data
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