783 research outputs found

    Space storable thrustor investigation Final report

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    Design and performance of space storable liquid FLOX methane thrustor of refractory composite material

    Wide range operation of advanced low NOx combustors for supersonic high-altitude aircraft gas turbines

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    An initial rig program tested the Jet Induced Circulation (JIC) and Vortex Air Blast (VAB) systems in small can combustor configurations for NOx emissions at a simulated high altitude, supersonic cruise condition. The VAB combustor demonstrated the capability of meeting the NOx goal of 1.0 g NO2/kg fuel at the cruise condition. In addition, the program served to demonstrate the limited low-emissions range available from the lean, premixed combustor. A follow-on effort was concerned with the problem of operating these lean, premixed combustors with acceptable emissions at simulated engine idle conditions. Various techniques have been demonstrated that allow satisfactory operation on both the JIC and VAB combustors at idle with CO emissions below 20 g/kg fuel. The VAB combustor was limited by flashback/autoignition phenomena at the cruise conditions to a pressure of 8 atmospheres. The JIC combustor was operated up to the full design cruise pressure of 14 atmospheres without encountering an autoignition limitation although the NOx levels, in the 2-3 g NO2/kg fuel range, exceeded the program goal

    Union effectiveness: In Search of the Holy Grail

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    YesThis article revisits the concept of union effectiveness and proposes a conceptual model to inform its study and application. Previous conceptual and empirical work is examined to identify key strengths and weaknesses, and to relate the union effectiveness concept to union renewal and other key concepts. This leads to the proposal of a Goal-System framework that builds and improves on prior research

    Inflammatory status and cartilage regenerative potential of synovial fibroblasts from patients with osteoarthritis and chondropathy.

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    OBJECTIVES: To evaluate the inflammatory status and the cartilage regenerative potential of pathological synovial fibroblasts from patients with osteoarthritis (OA) compared with non-inflamed synovium (NS)-derived cells from patients with chondropathy. METHODS: The inflammatory cell phenotype was investigated based on the constitutive and inducible surface expression and secretion of various effector molecules using flow cytometry or ELISA assays. The capacity of cells to produce cartilage-like extracellular matrix was assessed using acid Alcian blue staining and type II collagen immunostaining after treatment with transforming growth factor beta1 (TGF-beta1). RESULTS: OA and NS fibroblasts consistently expressed CD29, CD44, CD49e, CD54, CD90 and CD106. Expression of high-affinity receptors for IL-4, IL-15, CXCL8 and CXCL12 was also detected but only intracellularly. All types of fibroblasts spontaneously released abundant amounts of CXCL12, CCL2, IL-6 and tissue inhibitor of metalloproteinase 1, while the production of IL-11, TGF-beta1, matrix metalloproteinase 1 (MMP-1) and MMP-9 was detected at moderate levels. Several other secreted factors remained undetectable. No statistically significant differences were noted between the two groups of fibroblasts. Treatment with the proinflammatory cytokine tumour necrosis factor alpha (TNF-alpha) up-regulated the same set of surface and secreted molecules, including CD54, CD106, membrane IL-15, CCL2 and CCL5. Under TGF-beta1 treatment and adipogenic culture conditions, both OA and NS fibroblasts displayed chondrogenic and adipocytic activities that were reduced in OA compared with NS cells. CONCLUSIONS: OA synovial fibroblasts did not display a distinct activated inflammatory phenotype compared with NS cells. However, they did differ in their reduced ability to produce cartilage-like matrix. This difference may be an additional important factor contributing to OA pathogenesis

    ¿Intento de una Congregación General de la Compañía de Jesús en el año 1545?

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    La promulgación de las Constituciones de la Compañía de Jesús en vida de S. Ignacio de Loyola

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    La "Determinación de la Compañía" del año 1540

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