2,127 research outputs found

    Static internal performance of single-expansion-ramp nozzles with thrust-vectoring capability up to 60 deg

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    An investigation has been conducted at static conditions (wind off) in the static-test facility of the Langley 16-Foot Transonic Tunnel. The effects of geometric thrust-vector angle, sidewall containment, ramp curvature, lower-flap lip angle, and ramp length on the internal performance of nonaxisymmetric single-expansion-ramp nozzles were investigated. Geometric thrust-vector angle was varied from -20 deg. to 60 deg., and nozzle pressure ratio was varied from 1.0 (jet off) to approximately 10.0

    Dr William Parker (1766-1838)

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    Dr. William Parker was born in the colony of Georgia in 1766 and achieved prominence as a physician and community leader. He was one of the original members of the Georgia Medical Society, which was established in Savannah in 1804. Additionally, he was a member of Christ Church and on the Board of Trustees for Beth­esda Orphanage. In 1804 he married the widow Louisa Guerard Mc Allister who was originally from Prince William\u27s Parish in South Carolina, Dr. Parker was a descendant of Henry Parker, the second pres­ident of the colony of Georgia and one of the first settlers of the Isle of Hope. Henry Parker and his wife, Ann, arrived in Savannah in August 1733 with General James Oglethorpe. While visiting his country home on the Isle of Hope, Dr. Parker was paralyzed by a stroke and died two years later in 1838, at his residence on Bryan Street in Savannah.https://digitalcommons.georgiasouthern.edu/sav-bios-lane/1158/thumbnail.jp

    Operating Characteristics of the Multiple Critical Venturi System and Secondary Calibration Nozzles Used for Weight-Flow Measurements in the Langley 16-Foot Transonic Tunnel

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    An investigation has been conducted in the Langley 16 Foot Transonic Tunnel to determine the weight flow measurement characteristics of a multiple critical Venturi system and the nozzle discharge coefficient characteristics of a series of convergent calibration nozzles. The effects on model discharge coefficient of nozzle throat area, model choke plate open area, nozzle pressure ratio, jet total temperature, and number and combination of operating Venturis were investigated. Tests were conducted at static conditions (tunnel wind off) at nozzle pressure ratios from 1.3 to 7.0

    Extent and Mechanism of Footwall Shear Adjacent to the Ruby\u27s Inn Thrust Fault, Southern Utah

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    The Ruby’s Inn Thrust, located in the Bryce Canyon region, is an uncharacteristic demonstration of a south-directed shortening episode located near the predominately east-directed contractional structures of the Sevier Orogeny. The Paleocene to Eocene Claron Formation in the footwall of the Ruby’s Inn Thrust contains conjugate shear structures and vertical fault planes with slickensides and slickenlines, indicating complex multidirectional shearing. We determined the north-south extent of a broad shear zone along a traverse immediately west of Bryce Canyon National Park, and shearing intensifies slowly from the main thrust at the northern end of our traverse to a maximum intensity at 13 kilometers south of the thrust, where it then gradually diminishes until an abrupt end approximately 29 kilometers south of the thrust. No evidence of conjugate shear structures in the hanging wall of the thrust was observed. The footwall outcrops adjacent to the thrust and at the southern portion of the traverse contained the structures, but they were more difficult to visually recognize, whereas the structures within the outcrops of the central region were obvious. The conjugate shear structures crosscut bedding and vary from small scale (a few centimeters) to large scale (tens of meters) throughout each outcrop, and are best observed parallel to their east-west strike. The conjugate shear structures contain distinct structural planar surfaces that include very well developed slickensides and slickenlines. This research supports the idea that the deformation structures were a significant contributor in the formation of hoodoos found in the Claron Formation

    Evaluation of rations used in performance testing of bulls and steers

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    Cover title.Includes bibliographical references

    Variability of Luminous Stars in the Large Magellanic Cloud Using 10 Years of ASAS Data

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    Motivated by the detection of a recent outburst of the massive luminous blue variable LMC-R71, which reached an absolute magnitude M_V = -9.3 mag, we undertook a systematic study of the optical variability of 1268 massive stars in the Large Magellanic Cloud, using a recent catalog by Bonanos et al. (2009) as the input. The ASAS All Star Catalog (Pojmanski 2002) provided well-sampled light curves of these bright stars spanning 10 years. Combining the two catalogs resulted in 599 matches, on which we performed a variability search. We identified 117 variable stars, 38 of which were not known before, despite their brightness and large amplitude of variation. We found 13 periodic stars that we classify as eclipsing binary (EB) stars, eight of which are newly discovered bright, massive eclipsing binaries composed of OB type stars. The remaining 104 variables are either semi- or non-periodic, the majority (85) being red supergiants. Most (26) of the newly discovered variables in this category are also red supergiants with only three B and four O stars.Comment: 23 pages, 10 figures and 3 tables; published in A

    TOPEX/Poseidon orbit maintenance for the first five years

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    The TOPEX/Poseidon orbit maintenance strategy was changed following launch to include the effects of observed unmodeled, and hence anomalous, along-track accelerations. The anomalous force causes the semi-major axis, a, to either increase (called "boost") or decrease ("deboost" or "decay") depending on the satellite attitude and solar array pitch angle offset. Although this force is the most uncertain parameter in ground track prediction, it has been used as a passive technique for orbit maintenance, thereby reducing the number of propulsive maneuvers, enhancing maneuver spacing, and to place maneuvers at convenient times. This passive technique was first demonstrated in May 1993. The TOPEX/Poseidon orbit has been uniquely maintained using both passive (non-propulsive) and active (propulsive) maneuvers. Furthermore, the orbit has been maintained using only the passive technique since the ninth orbit maintenance maneuver on January 15, 1996. Only nine orbit maintenance maneuvers have been required to maintain the ground track, including verification site over flights, since achieving the operational orbit on September 21, 1992 (mission requirement: 95% within +/- l km). During this period, a has varied within 7,714,429 +/- 7 m, while the inclination i periodically fluctuated in the range 66.0408 deg. +/- 0.0040 deg. The frozen orbit (required e < 0.001 and omega approximately equals to 90 deg.) has been maintained without any dedicated eccentricity maneuvers. The frozen eccentricity vector has completed two periodic cycles and it is currently tracing its third cycle (period approximately equals 26.7 months)

    Tracking system analytic calibration activities for the Mariner Mars 1971 mission

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    Data covering various planning aspects of Mariner Mars 1971 mission are summarized. Data cover calibrating procedures for tracking stations, radio signal propagation in the troposphere, effects of charged particles on radio transmission, orbit calculation, and data smoothing
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