20,054 research outputs found
Eight-channel telephone telemetry system
Portable telemetry system uses conventional telephone link which eliminates mailing or messenger service between physician and analyst. Transmitter is used by physician; receiver is used by analyst. Each unit is inductively coupled to its respective telephone set, transmitter converting EEG into audio frequency and receiver converting this frequency back to EEG
An analysis of Jupiter data from the RAE-1 satellite
The analysis of Radio Astronomy Explorer Satellite data are presented. Radio bursts from Jupiter are reported in the frequency range 4700 KHz to 45 KHz. Strong correlations with lo were found at 4700, 3930, and 2200 KHz, while an equally strong Europa effect was observed at 1300, 900, and 700 KHz. Histograms indicating the relative probability and the successful identification of Jupiter activity were plotted, using automatic computer and visual search techniques
Prediction of boundary-layer characteristics of an oscillating airfoil
The evolution of unsteady boundary layers on oscillating airfoils is investigated by solving the governing equations by the Characteristic Box scheme. The difficulties associated with computing the first profile on a given time line, and the velocity profiles with partial flow reversal are solved. A sample calculation is performed for an external velocity distribution typical of those found near the leading edge of thin airfoils. The viability of the calculation procedure is demonstrated
Calculation of boundary layers near the stagnation point of an oscillating airfoil
The results of an investigation of boundary layers close to the stagnation point of an oscillating airfoil are reported. Two procedures for generating initial conditions, the characteristics box scheme and a quasi-static approach, were investigated, and the quasi-static approach was shown to be appropriate provided the initial region was far from any flow separation. With initial conditions generated in this way, the unsteady boundary layer equations were solved for the flow in the leading edge region of a NACA 0012 airfoil oscillating from 0 to 5 deg. Results were obtained for both laminar and turbulent flow, and, in the latter case, the effect of transition was assessed by specifying its occurrence at different locations. The results demonstrate the validity of the numerical scheme and suggest that the procedures should be applied to calculation of the entire flow around oscillating airfoils
Analysis procedures and subjective flight results of a simulator validation and cue fidelity experiment
A joint experiment to investigate simulator validation and cue fidelity was conducted by the Dryden Flight Research Facility of NASA Ames Research Center (Ames-Dryden) and NASA Langley Research Center. The primary objective was to validate the use of a closed-loop pilot-vehicle mathematical model as an analytical tool for optimizing the tradeoff between simulator fidelity requirements and simulator cost. The validation process includes comparing model predictions with simulation and flight test results to evaluate various hypotheses for differences in motion and visual cues and information transfer. A group of five pilots flew air-to-air tracking maneuvers in the Langley differential maneuvering simulator and visual motion simulator and in an F-14 aircraft at Ames-Dryden. The simulators used motion and visual cueing devices including a g-seat, a helmet loader, wide field-of-view horizon, and a motion base platform
Nano-Engineering Defect Structures on Graphene
We present a new way of nano-engineering graphene using defect domains. These
regions have ring structures that depart from the usual honeycomb lattice,
though each carbon atom still has three nearest neighbors. A set of stable
domain structures is identified using density functional theory (DFT),
including blisters, ridges, ribbons, and metacrystals. All such structures are
made solely out of carbon; the smallest encompasses just 16 atoms. Blisters,
ridges and metacrystals rise up out of the sheet, while ribbons remain flat. In
the vicinity of vacancies, the reaction barriers to formation are sufficiently
low that such defects could be synthesized through the thermally activated
restructuring of coalesced adatoms.Comment: 4 pages, 5 figure
Fractional charge excitations in fermionic ladders
The system of interacting spinless fermions hopping on a two-leg ladder in
the presence of an external magnetic field is shown to possess a long range
order: the bond density wave or the staggered flux phase. In both cases the
elementary excitations are kinks and carry one half the charge of an
electron.Comment: 4 pages, 3 figure
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