40,283 research outputs found

    Sun angle calculator

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    A circular computer and system is disclosed for determining the sun angle relative to the horizon from any given place and at any time. The computer includes transparent, rotatably mounted discs on both sides of the circular disc member. Printed on one side of the circular disc member are outer and inner circular sets of indicia respectively representative of site longitude and Greenwich Mean Time. Printed on an associated one of the rotatable discs is a set of indicia representative of Solar Time. Printed on the other side of the circular disc member are parallel lines representative of latitude between diametral representations of North and South poles. Elliptical lines extending between the North and South poles are proportionally disposed on the surface to scale Solar Time in hours

    Killian-Jamieson diverticulum mimicking a suspicious thyroid lesion

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    Killian-Jamieson diverticulum represents a rare form of esophageal diverticulum originating on the anterolateral wall of the cervical esophagus. Despite its rarity, it is crucial to recognize this entity, with such specific imaging findings, to avoid unnecessary invasive procedures such as fine-needle aspiration or even surgery.info:eu-repo/semantics/publishedVersio

    Abundances of Na, Sc, Cr, Mn, Fe, Co, and Cu in chondrules, Na, Mn, and Cu in meteorites, and In in meteoritic and terrestrial matter Quarterly progress report, 1 Dec. 1965 - 28 Feb. 1966

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    Element abundance in chondrules and meteorites measured by instrumental neutron activation analysis, and indium behavior in chondrite

    High-speed T-38A landing gear extension loads

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    Testing of T-38A landing gear extension at high speed and high altitude is described. The mechanisms are shown together with peak hydraulic pressure data during landing gear deployment with active and inactive strut door flaps. Results of strain gage measurements of stress on various structural members are included

    Abundances of trace elements Na, Sc, Cr, Mn, Fe, Co, and Cu in chondrules and meteorites in IN meteorites and terrestrial matter and U in type I carbonaceous chondrites Quarterly progress report, 1 Mar. - 15 Jun. 1966

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    Abundances of sodium, scandium, chromium, iron, manganese, cobalt, copper, indium, and uranium in chondrules, chondrites, and meteorites determined by neutron activation analysi

    Harmonic equiangular tight frames comprised of regular simplices

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    An equiangular tight frame (ETF) is a sequence of unit-norm vectors in a Euclidean space whose coherence achieves equality in the Welch bound, and thus yields an optimal packing in a projective space. A regular simplex is a simple type of ETF in which the number of vectors is one more than the dimension of the underlying space. More sophisticated examples include harmonic ETFs which equate to difference sets in finite abelian groups. Recently, it was shown that some harmonic ETFs are comprised of regular simplices. In this paper, we continue the investigation into these special harmonic ETFs. We begin by characterizing when the subspaces that are spanned by the ETF's regular simplices form an equi-isoclinic tight fusion frame (EITFF), which is a type of optimal packing in a Grassmannian space. We shall see that every difference set that produces an EITFF in this way also yields a complex circulant conference matrix. Next, we consider a subclass of these difference sets that can be factored in terms of a smaller difference set and a relative difference set. It turns out that these relative difference sets lend themselves to a second, related and yet distinct, construction of complex circulant conference matrices. Finally, we provide explicit infinite families of ETFs to which this theory applies

    Research on elemental abundances in meteoritic and terrestrial matter Summary progress report, 1 Sep. 1964 - 31 Aug. 1965

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    Element abundances determined by instrumental neutron activation analysis technique in individual chondrules separated from certain chondritic meteorite

    Massive pericardial effusion caused by hypothyroidism.

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    Although mild pericardial effusion is a usual finding in patients with hypothyroidism, massive pericardial effusion or pericardial tamponade is rare and customarily related to severe hypothyroidism. The diagnosis of hypothyroidism should be considered in the differential of patients presenting with unexplained pericardial effusion, even when signs and symptoms of hypothyroidism are nonexistent.info:eu-repo/semantics/publishedVersio
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