4,078 research outputs found
Low-speed wind-tunnel investigation of a large scale advanced arrow-wing supersonic transport configuration with engines mounted above wing for upper-surface blowing
Tests have been conducted in a full scale tunnel to determine the low speed aerodynamic characteristics of a large scale advanced arrow wing supersonic transport configuration with engines mounted above the wing for upper surface blowing. Tests were made over an angle of attack range of -10 deg to 32 deg, sideslip angles of + or - 5 deg, and a Reynolds number range of 3,530,000 to 7,330,000. Configuration variables included trailing edge flap deflection, engine jet nozzle angle, engine thrust coefficient, engine out operation, and asymmetrical trailing edge boundary layer control for providing roll trim. Downwash measurements at the tail were obtained for different thrust coefficients, tail heights, and at two fuselage stations
Low-speed wind-tunnel investigation of a large-scale advanced arrow wing supersonic transport configuration with engines mounted above the wing for upper-surface blowing
The Langley full scale tunnel was used to investigate the low speed stability and control of an advanced arrow wing supersonic transport with engines mounted above the wing for upper-surface blowing. Tests were made over an angle of attack range of -10 to 32 deg, slideslip angles of + or -5 deg and a Reynolds number ranging from 3.53 million to 7.33 million (referenced to mean aerodynamic chord of the wing). Configuration variables included trailing-edge flap deflection, engine jet nozzle angle, engine thrust coefficient, engine out operation, and asymmetrical trailing-edge BLC for providing roll trim. Downwash measurements at the tail were obtained for different thrust coefficients, tail heights, and at two fuselage stations
Spin period change and the magnetic fields of neutron stars in Be X-ray binaries in the Small Magellanic Cloud
We report on the long-term average spin period, rate of change of spin period
and X-ray luminosity during outbursts for 42 Be X-ray binary systems in the
Small Magellanic Cloud. We also collect and calculate parameters of each system
and use these data to determine that all systems contain a neutron star which
is accreting via a disc, rather than a wind, and that if these neutron stars
are near spin equilibrium, then over half of them, including all with spin
periods over about 100 s, have magnetic fields over the quantum critical level
of 4.4x10^13 G. If these neutron stars are not close to spin equilibrium, then
their magnetic fields are inferred to be much lower, of the order of 10^6-10^10
G, comparable to the fields of neutron stars in low-mass X-ray binaries. Both
results are unexpected and have implications for the rate of magnetic field
decay and the isolated neutron star population.Comment: 22 pages, 50 figures; to appear in MNRA
The binary period and outburst behaviour of the SMC X-ray binary pulsar system SXP504
A probable binary period has been detected in the optical counterpart to the
X-ray source CXOU J005455.6-724510 = RX J0054.9-7245 = AXJ0054.8-7244 = SXP504
in the Small Magellanic Cloud. This source was detected by Chandra on 04 Jul
2002 and subsequently observed by XMM-Newton on 18 Dec 2003. The source is
coincident with an Optical Gravitational Lensing (OGLE) object in the
lightcurves of which several optical outburst peaks are visible at ~ 268 day
intervals. Timing analysis shows a period of 268.6 +/- 0.1 days at > 99%
significance. Archival Rossi X-ray Timing Explorer (RXTE) data for the 504s
pulse-period has revealed detections which correspond closely with predicted or
actual peaks in the optical data. The relationship between this orbital period
and the pulse period of 504s is within the normal variance found in the Corbet
diagram.Comment: Accepted by MNRAS. 1 LATEX page. 4 figure
X-ray observations of AM Herculis from OSO-8
The white dwarf binary system AM Herculis (2A1815+500) was observed in X-rays at both low energies (E less 10 keV) and higher energies. The exact shape of the spectrum, particularly at the higher energies, has yet to be determined. Results from the high energy scintillation spectrometer on OSO-8 are presented. These are combined with results published elsewhere obtained concurrently with the proportional counter on the same satellite, thereby giving for the first time coincident observations of AM Her over the range 2 to 250 keV
Overview of the Langley subsonic research effort on SCR configuration
Recent advances achieved in the subsonic aerodynamics of low aspect ratio, highly swept wing designs are summarized. The most significant of these advances was the development of leading edge deflection concepts which effectively reduce leading edge flow separation. The improved flow attachment results in substantial improvements in low speed performance, significant delay of longitudinal pitch up, increased trailing edge flap effectiveness, and increased lateral control capability. Various additional theoretical and/or experimental studies are considered which, in conjunction with the leading edge deflection studies, form the basis for future subsonic research effort
Ectopic Origin of a Coronary Artery from the Aorta. Sudden Death in 3 of 23 Patients.
Ectopic origin of a coronary artery from the aorta is uncommon. In the last decade, its importance as a possible cause of sudden death has been documented. Initially, only the left coronary artery was implicated. Lately, the ectopically arising right coronary artery has also been shown to be involved in cases of sudden death. We reviewed the pathologic anatomy in 23 cases of ectopic origin of a coronary artery from the aorta. In three of these cases, death could be attributed to ectopic origin of a coronary artery. In one case the left coronary artery arose from the right aortic sinus, and in two cases the right coronary artery arose from the left aortic sinus. In one of these, a scar of healed myocardial infarction was present in the inferior wall of the left ventricle. The possible mechanism for sudden death in these cases is reviewed and emphasis placed on the theory that the acute angle at which the ectopic artery leaves the aorta results in a flap-like mechanism at the arterial ostium. Ostial stenosis by the flap could be a significant factor in causing myocardial ischemia in some patients and also in sudden death
Effects of upper-surface blowing and thrust vectoring on low speed aerodynamic characteristics of a large-scale supersonic transport model
Tests were conducted in a full scale tunnel to determine the low speed aerodynamic characteristics of a large scale arrow wing supersonic transport configured with engines mounted above the wing for upper surface blowing and conventional lower surface engines having provisions for thrust vectoring. Tests were conducted over an angle of attack range of -10 deg to 34 deg and for Reynolds numbers (based on the mean aerodynamic chord) of 5.17 x 1 million and 3.89 x 1 million. A limited number of tests were also conducted for the upper surface engine configuration in the high lift condition at an angle of sideslip of 10 deg in order to evaluate lateral directional characteristics and with the right engine inoperative in order to evaluate the engine out condition
The 78.4 day period of Cygnus XR-1
A search for a 78.4 day modulation in the high energy X-ray flux observed with OSO-8 and in the U-band optical polarization is reported. It is suggested that if such a modulation does exist, it is more likely to be related to the rotation of the free modes of oscillation of the primary than to the existence of a third body in the system
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