39,157 research outputs found
Offshore Space Center (offshore launch site)
Any activity requiring the development of the HLLV can benefit by operations from an offshore space center (OSC) since operating near the equator provides a twenty percent increase in payload in an ecliptic plan orbit. Some OSC concepts considered include a moored floating (semisubmersible) design, a stationary design supported by fixed piles, and a combination of these two. The facility supports: a 15,000 foot long, 300 foot wide runway, designed to accommodate a two staged winged launch vehicle, with a one million pound payload capacity to low earth orbit; an industrial area for HLLV maintenance; an airport terminal, control and operation center, and observation tower; liquid hydrogen and liquid oxygen production and storage, and fuel storage platforms; a power generation station, docks with an unloading area; two separate launch sites; and living accommodations for 10,000 people. Potential sites include the Paramount Seamount in the Pacific Ocean off the north coast of South America. Cost estimates are considered
Effect of rod gap spacing on a suction panel for laminar flow and noise control in supersonic wind tunnels
Results are presented of a coordinated experimental and theoretical study of a sound shield concept which aims to provide a means of noise reduction in the test section of supersonic wind tunnels at high Reynolds numbers. The model used consists of a planar array of circular rods aligned with the flow, with adjustable gaps between them for boundary layer removal by suction, i.e., laminar flow control. One of the basic requirements of the present sound shield concept is to achieve sonic cross flow through the gaps in order to prevent lee-side flow disturbances from penetrating back into the shielded region. Tests were conducted at Mach 6 over a local unit Reynolds number range from about 1.2 x 10 to the 6th power to 13.5 x 10 to the 6th power per foot. Measurements of heat transfer, static pressure, and sound levels were made to establish the transition characteristics of the boundary layer on the rod array and the sound shielding effectiveness
Flexible drive allows blind machining and welding in hard-to-reach areas
Flexible power and control unit performs welding and machining operations in confined areas. A machine/weld head is connected to the unit by a flexible transmission shaft, and a locking- indexing collar is incorporated onto the head to allow it to be placed and held in position
Instrument accurately measures small temperature changes on test surface
Calorimeter apparatus accurately measures very small temperature rises on a test surface subjected to aerodynamic heating. A continuous thin sheet of a sensing material is attached to a base support plate through which a series of holes of known diameter have been drilled for attaching thermocouples to the material
Heat sensing instrument Patent
Heat sensing instrument, using thermocouple junction connected under heavy conducting materia
Solitary Waves in Optical Fibers Governed by Higher Order Dispersion
An exact solitary wave solution is presented for the nonlinear Schrodinger
equation governing the propagation of pulses in optical fibers including the
effects of second, third and fourth order dispersion. The stability of this
soliton-like solution with sech2 shape is proven by the sign-definiteness of
the operator and an integral of the Sobolev type. The main criteria governing
the existence of such stable localized pulses propagating in optical fibers are
also formulated. A unique feature of these soliton-like optical pulses
propagating in a fiber with higher order dispersion is that their parameters
satisfy efficient scaling relations. The main soliton solution term given by
perturbation theory is also presented when absorption or gain is included in
the nonlinear Schrodinger equation. We anticipate that this type of stable
localized pulses could find practical applications in communications,
slow-light devices and ultrafast lasers.Comment: 4 pages 3 Figure
- …