Grid Fin Stabilization of the Orion Launch Abort Vehicle

Wind tunnel tests were conducted by Nielsen Engineering & Research (NEAR) and Rose Engineering & Research (REAR) in conjunction with the NASA Engineering & Safety Center (NESC) on a 6%-scale model of the Orion launch abort vehicle (LAV) configured with four grid fins mounted near the base of the vehicle. The objectives of these tests were to 1) quantify LAV stability augmentation provided by the grid fins from subsonic through supersonic Mach numbers, 2) assess the benefits of swept grid fins versus unswept grid fins on the LAV, 3) determine the effects of the LAV abort motors on grid fin aerodynamics, and 4) generate an aerodynamic database for use in the future application of grid fins to small length-to-diameter ratio vehicles similar to the LAV. The tests were conducted in NASA Ames Research Center's 11x11-foot transonic wind tunnel from Mach 0.5 through Mach 1.3 and in their 9x7-foot supersonic wind tunnel from Mach 1.6 through Mach 2.5. Force- and moment-coefficient data were collected for the complete vehicle and for each individual grid fin as a function of angle of attack and sideslip angle. Tests were conducted with both swept and unswept grid fins with the simulated abort motors (cold jets) off and on. The swept grid fins were designed with a 22.5deg aft sweep angle for both the frame and the internal lattice so that the frontal projection of the swept fins was the same as for the unswept fins. Data from these tests indicate that both unswept and swept grid fins provide significant improvements in pitch stability as compared to the baseline vehicle over the Mach number range investigated. The swept fins typically provide improved stability as compared to the unswept fins, but the performance gap diminished as Mach number was increased. The aerodynamic performance of the fins was not observed to degrade when the abort motors were turned on. Results from these tests indicate that grid fins can be a robust solution for stabilizing the Orion LAV over a wide range of operating conditions

Salvage surgery for squamous cell carcinoma of the head and neck in the era of immunotherapy: Is it time to clarify our guidelines?

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146561/1/cncr31717_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146561/2/cncr31717.pd

Selecting a comparison group for 5-year oral and pharyngeal cancer survivors: Two methods

BACKGROUND: To assess potential long-term consequences of cancer treatment, studies that include comparison groups are needed. These comparison groups should be selected in a way that allows the subtle long-range effects of cancer therapy to be detected and distinguishes them from the effects of aging and other risk factors. The purpose of this investigation was to test two methods of recruiting a comparison group for 5-year oral and pharyngeal cancer survivors (peer-nominated and listed sample) with emphasis on feasibility and the quality of the match. METHODS: Participants were drawn from a pool of 5-year survivors treated at a large Southeastern hospital. A peer-nominated sample was solicited from the survivors. A listed sample matched on sex, age, and zip code was purchased. Telephone interviews were conducted by a professional call center. RESULTS: The following represent our key findings: The quality of matching between survivors and listed sample was better than that between survivors and peer-nominated group in age and sex. The quality of matching between the two methods on other key variables did not differ except for education, with the peer method providing a better match for the survivors than the listed sample. The yield for the listed sample method was greater than for the peer-nominated method. The cost per completed interview was greater for the peer-nominated method than the listed sample. CONCLUSION: This study not only documents the methodological challenges in selecting a comparison group for studies examining the late effects of cancer treatment among older individuals but also documents challenges in matching groups that potentially have disproportionate levels of comorbidities and at-risk health behaviors

Earnings Surprises and the Options Market

Numerous articles over the past few decades have documented a consistent relationship between earnings surprises and subsequent stock price performance. [See, for example, Ball and Brown (1968), Rendleman, Jones, and Latane (1982), Foster, Olsen, and Shevlin (1984), and Bernard and Thomas (1989).] Specifically when firms announce quarterly earnings figures that are higher (lower) than market expectations, as proxied by either mechanical time-series models or commercially available analysts’ forecasts, the stock price performance following the announcement tends to be abnormally good (bad). This phenomenon is referred to as post-earnings-announcement drift or the standardized unexpected earnings effect, SUE for short

Earnings Surprises and the Options Market

Numerous articles over the past few decades have documented a consistent relationship between earnings surprises and subsequent stock price performance. [See, for example, Ball and Brown (1968), Rendleman, Jones, and Latane (1982), Foster, Olsen, and Shevlin (1984), and Bernard and Thomas (1989).] Specifically when firms announce quarterly earnings figures that are higher (lower) than market expectations, as proxied by either mechanical time-series models or commercially available analysts’ forecasts, the stock price performance following the announcement tends to be abnormally good (bad). This phenomenon is referred to as post-earnings-announcement drift or the standardized unexpected earnings effect, SUE for short

The Sky is Falling: Chemical Characterization and Corrosion Evaluation of Deposition Produced During the Static Testing of Solid Rocket Motors

Static tests of horizontally restrained rocket motors at the ATK facility in Promontory UT, USA result in the deposition of entrained soil and fuel combustion products, referred to as Test Fire Soil (TFS), over areas as large as 30–50 mile2 (80–130 km2) and at distances up to 10–12 miles (16–20 km) from the test site. Chloride is the main combustion product generated from the ammonium perchlorate–aluminum based composite propellant. Deposition sampling/characterization and a 6-month field corrosivity study using mild steel coupons were conducted in conjunction with the February 25th 2010 FSM-17 static test. The TFS deposition rates at the three study sites ranged from 1 to 5 g/min/m2. TFS contained significantly more chloride than the surface soil collected from the test site. The TFS collected during two subsequent tests had similarly elevated chloride, suggesting that the results obtained in this study are applicable to other tests assuming that the rocket fuel composition remains similar. The field-deployed coupons exposed to the TFS had higher corrosion rates (3.6–5.0 mpy) than paired non-exposed coupons (1.6–1.8 mpy). Corrosion rates for all coupon

When is radiation therapy in head and neck squamous cell carcinoma not indicated?

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Comparative effectiveness study of patient‐reported outcomes after proton therapy or intensity‐modulated radiotherapy for prostate cancer

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106701/1/cncr28536.pd