28,034 research outputs found
Summary refurbishment cost study of the thermal protection system of a space shuttle vehicle
Analysis of costs to refurbish thermal protection system for space shuttle
Testing conformal mapping with kitchen aluminum foil
We report an experimental verification of conformal mapping with kitchen
aluminum foil. This experiment can be reproduced in any laboratory by
undergraduate students and it is therefore an ideal experiment to introduce the
concept of conformal mapping. The original problem was the distribution of the
electric potential in a very long plate. The correct theoretical prediction was
recently derived by A. Czarnecki (Can. J. Phys. 92, 1297 (2014))
Using LANDSAT digital data for estimating green biomass
The author has identified the following significant results. Relationships between the quantity of mixed prairie rangeland vegetation and LANDSAT MSS response were studied during four growing seasons at test sites throughout the United States Great Plans region. A LANDSAT derived parameter, the normalized difference was developed from theoretical considerations fro statistical estimation of the amount and seasonal condition of rangeland vegetation. This parameter was tested for application to local assessment of green forage biomass and regional monitoring of range feed conditions and drought. Results show that for grasslands in the Great Plains with near continuous vegetative cover and free of heavy brush and forbs, the LANDSAT digital data can provide a useful estimate of the quantity of green forage biomass (within 250 kg/ha), and at least five levels of pasture and range feed conditions can be adequately mapped for extended regions
Comparison of classical and second quantized description of the dynamic Stark shift
We compare the derivation of the dynamic Stark shift of hydrogenic energy
levels in a classical framework with an adiabatically damped laser-atom
interaction, which is equivalent to the Gell-Mann-Low-Sucher formula, and a
treatment based on time-independent perturbation theory, with a
second-quantized laser-atom dipole interaction Hamiltonian. Our analysis
applies to a laser that excites a two-photon transition in atomic hydrogen or
in a hydrogenlike ion with low nuclear charge number. Our comparisons serve to
demonstrate why the dynamic Stark shift may be interpreted as a stimulated
radiative correction and illustrates connections between the two derivations.
The simplest of the derivations is the fully quantized approach. The classical
and the second-quantized treatment are shown to be equivalent in the limit of
large photon numbers.Comment: 5 page
Refurbishment cost study of the thermal protection system of a space shuttle vehicle. Phase 2: Supplement
The labor costs and techniques associated with the maintenance of a bonded-on ablator thermal protection system (TPS) concept, suitable for Space Shuttle application are examined. The baseline approach to TPS attachment involves bonding reusable surface insulation (RSI) and/or ablators to the structural skin of the vehicle. The RSI and/or ablators in the form of either flat or contoured panels can be bonded to the skin of the primary structure directly or by way of an intermediate silicone foam rubber pad. The use of foam rubber pads permits the use of buckling skins and protruding heat rivets on the primary structure, minimizing structural weight and fabrication costs. In the case of the RSI, the foam rubber pad serves as a required strain isolator. For purpose of comparison, test data were obtained for an installation with and without the use of a strain isolator. The refurbishment aspects of a bonded-on RSI concept (without a strain isolator) were examined experimentally along with several externally removable panel concepts employing both ablator and RSI TPS. The various concepts are compared
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