55 research outputs found

    A static investigation of the thrust vectoring system of the F/A-18 high-alpha research vehicle

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    A static (wind-off) test was conducted in the static test facility of the Langley 16-foot Transonic Tunnel to evaluate the vectoring capability and isolated nozzle performance of the proposed thrust vectoring system of the F/A-18 high alpha research vehicle (HARV). The thrust vectoring system consisted of three asymmetrically spaced vanes installed externally on a single test nozzle. Two nozzle configurations were tested: A maximum afterburner-power nozzle and a military-power nozzle. Vane size and vane actuation geometry were investigated, and an extensive matrix of vane deflection angles was tested. The nozzle pressure ratios ranged from two to six. The results indicate that the three vane system can successfully generate multiaxis (pitch and yaw) thrust vectoring. However, large resultant vector angles incurred large thrust losses. Resultant vector angles were always lower than the vane deflection angles. The maximum thrust vectoring angles achieved for the military-power nozzle were larger than the angles achieved for the maximum afterburner-power nozzle

    Multiaxis Thrust-Vectoring Characteristics of a Model Representative of the F-18 High-Alpha Research Vehicle at Angles of Attack From 0 deg to 70 deg

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    An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the multiaxis thrust-vectoring characteristics of the F-18 High-Alpha Research Vehicle (HARV). A wingtip supported, partially metric, 0.10-scale jet-effects model of an F-18 prototype aircraft was modified with hardware to simulate the thrust-vectoring control system of the HARV. Testing was conducted at free-stream Mach numbers ranging from 0.30 to 0.70, at angles of attack from O' to 70', and at nozzle pressure ratios from 1.0 to approximately 5.0. Results indicate that the thrust-vectoring control system of the HARV can successfully generate multiaxis thrust-vectoring forces and moments. During vectoring, resultant thrust vector angles were always less than the corresponding geometric vane deflection angle and were accompanied by large thrust losses. Significant external flow effects that were dependent on Mach number and angle of attack were noted during vectoring operation. Comparisons of the aerodynamic and propulsive control capabilities of the HARV configuration indicate that substantial gains in controllability are provided by the multiaxis thrust-vectoring control system

    The age of the Pentateuch

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    Prominent Plasmacytosis Following Intravenous Immunoglobulin Correlates with Clinical Improvement in Guillain-Barré Syndrome

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    BACKGROUND: High doses of pooled polyclonal IgG are commonly used to treat numerous autoimmune diseases. Their mode of action nevertheless remains only partially explained. At the same time, until now, no early biological marker has been able to predict their efficacy. METHODOLOGY/PRINCIPAL FINDINGS: In a first pilot retrospective analysis, we reviewed white blood cell counts and blood smears in consecutive patients with autoimmune disease (n = 202) and non-autoimmune disease (n = 104). Autoimmune patients received either intravenous immunoglobulin (IVIg, n = 103), plasma exchange (n = 78) or no specific treatment (n = 21). We then prospectively monitored consecutive autoimmune patients with IVIg injection (n = 67), or without any specific treatment (n = 10) using the same routine laboratory tests, as well as flow cytometry. Both retrospective and prospective analyses identified large plasma-cell mobilization exclusively in IVIg-treated autoimmune patients 7 days after initiation of treatment. The majority of IVIg-mobilized plasma cells were immature HLA-DR(high)/CD138(low)/CXCR4(low) plasma cells expressing intracellular immunoglobulin G which were neither IVIg- nor human IgG-specific. Importantly, we found a strong negative correlation between the absolute number of IVIg-mobilized plasma cells and time to improve neurological function in both retrospective and prospective studies of Guillain-Barré syndrome (GBS), (r = -0.52, p = 0.0031, n = 30, r = -0.47, p = 0.0028, n = 40, respectively). CONCLUSIONS/SIGNIFICANCE: IVIg promotes immature plasma-cell mobilization in patients with GBS, chronic inflammatory demyelinating polyneuropathy, myasthenia gravis and inflammatory myopathy. Prominent day 7 plasma-cell mobilization is a favourable prognostic marker in patients with GBS receiving IVIg treatment

    Journal clipping, A Life Worth While, by Dr. Francis Asbury, Alabama Christian Advocate, October 24, 1929

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    This is an item from the William Crawford Gorgas Papers. This collection includes material created by and written about Gorgas, as well as material created by Gorgas' family members. His diaries and journals illuminate his life and work for the U.S. Army as a surgeon and span the years he worked in Cuba and Panama. The collection includes official reports and other documents Gorgas wrote and collected, as well as articles and other publications written about Gorgas and his work in sanitation and disease prevention, particularly yellow fever. Correspondence, articles, and other items document the numerous awards and tributes Gorgas received during his life and memorials after his death in 1920. In addition to William Crawford Gorgas material, the collection includes other material belonging to Gorgas family members including Marie Gorgas and their daughter, Aileen Gorgas Wrightson. In 1924, his widow Marie Gorgas published William Crawford Gorgas: His Life and Work. This collection includes manuscripts, galley proofs, and published versions of her work

    The evolution of penology

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    Pruning Implement.

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    Patent for a new and improved pruning implement. This design consists in "the combination, with a staff, of the jaw-arms pivoted to the staff and provided with the upwardly-projecting and curved jaws, the collars fitted loosely on the staff, the rods connecting the said collars, and the link-arms pivoted to the collar and to the jaw-arms" (lines 11-17)

    Head injuries and their management

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