2,396 research outputs found
Research rocket test RR-1 (Black Brant VC) and RR-2 (Aerobee 170A): Investigations of the stability of bubbles in plain and fiber-reinforced metal and solidified in a near-zero-g environment
The results of the first two of a series of research rocket flights are presented. The objectives of these flights were (1) to learn about the capabilities of these rockets, (2) to learn how to interface the payloads and rockets, and (3) to process some of the composite casting demonstration capsules intended originally for Apollo 15. The capsules contained experiments for investigating the stability of gas bubbles in plain and fiber-reinforced metal melted and solidified in a near-zero-g (0.0119g) environment. The characteristics of the two research rockets, an Aerobee 170A and a Black Brant VC, used to obtain the periods of near-zero-g and the temperature control unit used for processing the contents of the two experiment capsules are discussed
Nondestructive assessment of penetration of electron-beam welds
Empirical method correlates penetration of an electron-beam weld with external measurements of the weld. Empirical polygon accurately confirms full-penetration welds while a second, larger polygon provides for penetration of welds near the tip
Perspectives on Professional Learning at the University of Tennessee Institute of Agriculture
Professional learning in higher education is changing from a workshop approach to long-term interactive learning. According to the Western Governor’s University (2017), this new form of professional development known as “professional learning” incorporates collaboration among educators to improve their teaching and development at work. The University of Tennessee (UT), Herbert College of Agriculture (Herbert) is incorporating new approaches to improve employee professional learning. To explore this learning environment two methods of professional learning were investigated including peer mentoring and faculty development in teaching higher order thinking. The Tennessee Extension Peer Mentoring Program was established to orient and mentor new extension agents at UT (Tennessee Mentoring Toolkit, 2015). The first study in this thesis contains a comprehensive literature review for this new program on employee confidence, competence, and job satisfaction. The review suggests that mentoring is beneficial to new employee orientation and has been found to increase employee confidence, competence, and job satisfaction. The second study in this thesis is a literature review and analysis of focus group data from faculty interviews. A team of Herbert researchers is seeking to create an environment of higher-order learning in accordance with the best management practices of the National Collegiate Honors Council. Herbert faculty participated in focus groups to identify strengths of the current program and to determine future needs to implement higher-ordered learning into curricula. The results suggested that faculty perceived problem solving as the greatest strength of the college and identified the need to improve students’ abilities in critical evaluation. The students’ fear of failure was identified as an impediment to teaching higher order thinking. Faculty realized a need to teach higher order thinking that builds upon each year in college and emphasizes a curricula wide approach. The faculty reported a need for professional development in teaching critical thinking and student assessment, preferably in a hands-on workshop with a group discussion format
QED \otimes QCD Threshold Corrections at the LHC
We use the theory of YFS resummation to compute the size of the expected
resummed soft radiative threshold effects in precision studies of heavy
particle production at the LHC, where accuracies of 1 percent are desired in
some processes. We find that the soft QED threshold effects are at the level of
0.3 percent whereas the soft QCD threshold effects enter at the level of 20
percent and hence both must be controlled to be on the conservative side to
achieve such goals.Comment: 8 pages, no figures; improved text; improved refs. and tex
The Virtual Correction to Bremsstrahlung in High-Energy e+ e- Annihilation: Comparison of Exact Results
We have compared the virtual corrections to single hard bremsstrahlung as
calculated by S. Jadach, M. Melles, B.F.L. Ward and S.A. Yost to several other
expressions. The most recent of these comparisons is to the leptonic tensor
calculated by J.H. Kuhn and G. Rodrigo for radiative return. Agreement is found
to within a part in 10^5 or better, as a fraction of the Born cross section,
for most of the range of photon energies. The massless limits have been shown
to agree analytically to NLL order.Comment: 7 pages, 2 figures. Presented by S.A. Yost at ICHEP 2004,
International Conference on High Energy Physics, Beijing, August 16-22, 200
Space shuttle orbit maneuvering engine reusable thrust chamber program
Tests were conducted on the regenerative cooled thrust chamber of the space shuttle orbit maneuvering engine. The conditions for the tests and the durations obtained are presented. The tests demonstrated thrust chamber operation over the nominal ranges of chamber pressure mixture ratio. Variations in auxiliary film coolant flowrate were also demonstrated. High pressure tests were conducted to demonstrate the thrust chamber operation at conditions approaching the design chamber pressure for the derivative space tug application
X ray sensitive area detection device
A radiation sensitive area detection device is disclosed which comprises a phosphor-containing film capable of receiving and storing an image formed by a pattern of incoming x rays, UV, or other radiation falling on the film. The device is capable of fluorescing in response to stimulation by a light source in a manner directly proportional to the stored radiation pattern. The device includes: (1) a light source capable of projecting light or other appropriate electromagnetic wave on the film so as to cause it to fluoresce; (2) a means to focus the fluoresced light coming from the phosphor-containing film after light stimulation; and (3) at least one charged coupled detector or other detecting element capable of receiving and digitizing the pattern of fluoresced light coming from the phosphor-containing film. The device will be able to generate superior x ray images of high resolution from a crystal or other sample and will be particularly advantageous in that instantaneous near-real-time images of rapidly deteriorating samples can be obtained. Furthermore, the device can be made compact and sturdy, thus capable of carrying out x ray or other radiation imaging under a variety of conditions, including those experienced in space
Preburner of Staged Combustion Rocket Engine
A regeneratively cooled LOX/hydrogen staged combustion assembly system with a 400:1 expansion area ratio nozzle utilizing an 89,000 Newton (20,000 pound) thrust regeneratively cooled thrust chamber and 175:1 tubular nozzle was analyzed, assembled, and tested. The components for this assembly include two spark/torch oxygen-hydrogen igniters, two servo-controlled LOX valves, a preburner injector, a preburner combustor, a main propellant injector, a regeneratively cooled combustion chamber, a regeneratively cooled tubular nozzle with an expansion area ratio of 175:1, an uncooled heavy-wall steel nozzle with an expansion area ratio of 400:1, and interconnecting ducting. The analytical effort was performed to optimize the thermal and structural characteristics of each of the new components and the ducting, and to reverify the capabilities of the previously fabricated components. The testing effort provided a demonstration of the preburner/combustor chamber operation, chamber combustion efficiency and stability, and chamber and nozzle heat transfer
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