56,256 research outputs found
The NASA digital VGH program, early results
Data from airline digital flight data recorders provides relevant statistical data for estimating fatigue life consumption of the current airliner fleet and for design criteria updating for future designs. The data indicates real operating effects due to the autopilot, i.e., gust response frequency peak increase by 2 or 3 times, and the existence of the low frequency low amplitude limit cycle motion in altitude hold. The extension of more data types for ground operations is considered. Onboard processing of simple data types is also considered
Sensitivity of Nonrenormalizable Trajectories to the Bare Scale
Working in scalar field theory, we consider RG trajectories which correspond
to nonrenormalizable theories, in the Wilsonian sense. An interesting question
to ask of such trajectories is, given some fixed starting point in parameter
space, how the effective action at the effective scale, Lambda, changes as the
bare scale (and hence the duration of the flow down to Lambda) is changed. When
the effective action satisfies Polchinski's version of the Exact
Renormalization Group equation, we prove, directly from the path integral, that
the dependence of the effective action on the bare scale, keeping the
interaction part of the bare action fixed, is given by an equation of the same
form as the Polchinski equation but with a kernel of the opposite sign. We then
investigate whether similar equations exist for various generalizations of the
Polchinski equation. Using nonperturbative, diagrammatic arguments we find that
an action can always be constructed which satisfies the Polchinski-like
equation under variation of the bare scale. For the family of flow equations in
which the field is renormalized, but the blocking functional is the simplest
allowed, this action is essentially identified with the effective action at
Lambda = 0. This does not seem to hold for more elaborate generalizations.Comment: v1: 23 pages, 5 figures, v2: intro extended, refs added, published in
jphy
Flow field for an underexpanded, supersonic nozzle exhausting into an expansive launch tube
Static pressure distributions along the launcher wall and pitot pressure measurements from the annular region between the rocket and the launcher were made as an underexpanded supersonic nozzle exhausted into an expansive launch tube. The flow remained supersonic along the entire length of the launcher for all nozzle locations studied
Thermionic performance of a variable-gap cesium diminiode with a 110-single-crystal-tungsten emitter and a polycrystalline-niobium collector
Results from tests of the first variable-gap diminiode at an initial interelectrode spacing of 0.23 millimeter indicate sharply defined, relatively low ultimate power points. This characteristic supports the value of the diminiode as a well-controlled tool for thermionic-conversion research and development
The Near-Infrared Broad Emission Line Region of Active Galactic Nuclei -- I. The Observations
We present high quality (high signal-to-noise ratio and moderate spectral
resolution) near-infrared (near-IR) spectroscopic observations of 23 well-known
broad-emission line active galactic nuclei (AGN). Additionally, we obtained
simultaneous (within two months) optical spectroscopy of similar quality. The
near-IR broad emission line spectrum of AGN is dominated by permitted
transitions of hydrogen, helium, oxygen, and calcium, and by the rich spectrum
of singly-ionized iron. In this paper we present the spectra, line
identifications and measurements, and address briefly some of the important
issues regarding the physics of AGN broad emission line regions. In particular,
we investigate the excitation mechanism of neutral oxygen and confront for the
first time theoretical predictions of the near-IR iron emission spectrum with
observations.Comment: 45 pages, 17 figures, accepted by ApJ
Development of a solid electrolyte carbon dioxide and water reduction system for oxygen recovery
A 1/4-man solid electrolyte oxygen regeneration system, consisting of an electrolyzer, a carbon deposition reactor, and palladium membranes for separating hydrogen, was operated continuously in a 180-day test. Oxygen recovery from the carbon dioxide-water feed was 95%. One percent of the oxygen was lost to vacuum with the hydrogen off-gas. In a space cabin, the remaining 4% would have been recycled to the cabin and recovered. None of the electrolysis cells used in the 180-day test failed. Electrolysis power rose 20% during the test; the average power was 283.5 watts/man. Crew time was limited to 18 min/day of which 12 min/day was used for removing carbon. The success achieved in operating the system can be attributed to an extensive component development program, which is described. Stability of operation, ease of control, and flexibility in feed composition were demonstrated by the life test
Research on gravitational mass sensors Quarterly progress report no. 1, 15 Oct. 1964 - 14 Jan. 1965
Lunar orbiter and deep space probe gravitational sensor for determining mass distribution of moon and asteroid
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