3,942 research outputs found
State-of-the-art survey of dissimilar metal joining by solid state welding
State-of-the-art of dissimilar metal joining by solid state diffusion bonding and roll and press welding, emphasizing stainless steel and aluminum allo
High pressure compressor component performance report
A compressor optimization study defined a 10 stage configuration with a 22.6:1 pressure ratio, an adiabatic efficiency goal of 86.1%, and a polytropic efficiency of 90.6%; the corrected airflow is 53.5 kg/s. Subsequent component testing included three full scale tests: a six stage rig test, a 10 stage rig test, and another 10 stage rig test completed in the second quarter of 1982. Information from these tests is used to select the configuration for a core engine test and an integrated core/low spool test. The test results will also provide data base for the flight propulsion system. The results of the test series with both aerodynamic and mechanical performance of each compressor build are presented. The second 10 stage compressor adiabatic efficiency was 0.848 at a cruise operating point versus a test goal of 0.846
Design of a large span-distributed load flying-wing cargo airplane with laminar flow control
A design study was conducted to add laminar flow control to a previously design span-distributed load airplane while maintaining constant range and payload. With laminar flow control applied to 100 percent of the wing and vertical tail chords, the empty weight increased by 4.2 percent, the drag decreased by 27.4 percent, the required engine thrust decreased by 14.8 percent, and the fuel consumption decreased by 21.8 percent. When laminar flow control was applied to a lesser extent of the chord (approximately 80 percent), the empty weight increased by 3.4 percent, the drag decreased by 20.0 percent, the required engine thrust decreased by 13.0 percent, and the fuel consumption decreased by 16.2 percent. In both cases the required take-off gross weight of the aircraft was less than the original turbulent aircraft
Preliminary design characteristics of a subsonic business jet concept employing laminar flow control
Aircraft configurations were developed with laminar flow control (LFC) and without LFC. The LFC configuration had approximately eleven percent less parasite drag and a seven percent increase in the maximum lift-to drag ratio. Although these aerodynamic advantages were partially offset by the additional weight of the LFC system, the LFC aircraft burned from six to eight percent less fuel for comparable missions. For the trans-atlantic design mission with the gross weight fixed, the LFC configuration would carry a greater payload for ten percent fuel per passenger mile
Preliminary design characteristics of a subsonic business jet concept employing an aspect ratio 25 strut braced wing
The advantages of replacing the conventional wing on a transatlantic business jet with a larger, strut braced wing of aspect ratio 25 were evaluated. The lifting struts reduce both the induced drag and structural weight of the heavier, high aspect ratio wing. Compared to the conventional airplane, the strut braced wing design offers significantly higher lift to drag ratios achieved at higher lift coefficients and, consequently, a combination of lower speeds and higher altitudes. The strut braced wing airplane provides fuel savings with an attendant increase in construction costs
One-nucleon transfer reactions and the optical potential
We provide a summary of new developments in the area of direct reaction
theory with a particular focus on one-nucleon transfer reactions. We provide a
status of the methods available for describing (d,p) reactions. We discuss the
effects of nonlocality in the optical potential in transfer reactions. The
results of a purely phenomenological potential and the optical potential
obtained from the dispersive optical model are compared; both point toward the
importance of including nonlocality in transfer reactions explicitly. Given the
large ambiguities associated with optical potentials, we discuss some new
developments toward the quantification of this uncertainty. We conclude with
some general comments and a brief account of new advances that are in the
pipeline.Comment: 7 pages, 5 figures, proceedings for the 14th International Conference
on Nuclear Reaction Mechanisms, Varenna, June 201
UNIAXIAL AND BIAXIAL CREEP-RUPTURE OF TYPE 316 STAINLESS STEEL AFTER FAST REACTOR IRRADIATION.
PKS 1830-211: A Possible Compound Gravitational Lens
Measurements of the properties of gravitational lenses have the power to tell
us what sort of universe we live in. The brightest known radio Einstein
ring/gravitational lens PKS 1830-211 (Jauncey et al., 1991), whilst obscured by
our Galaxy at optical wavelengths, has recently been shown to contain
absorption at the millimetre waveband at a redshift of 0.89 (Wiklind and
Combes, 1996a). We report the detection of a new absorption feature, most
likely due to neutral hydrogen in a second redshift system at z = 0.19.
Follow-up VLBI observations have spatially resolved the absorption and reveal
it to cover the NE compact component and part of the lower surface brightness
ring. This new information, together with existing evidence of the unusual VLBI
radio structure and difficulties in modeling the lensing system, points to the
existence of a second lensing galaxy along our line of sight and implies that
PKS 1830-211 may be a compound gravitational lens.Comment: 8 pages, 2 figures, LaTeX (aasms4.sty). Accepted for publication in
ApJ Letters. Preprint also available at
http://kerr.phys.utas.edu.au/preprints
A Compact Extreme Scattering Event Cloud Towards AO 0235+164
We present observations of a rare, rapid, high amplitude Extreme Scattering
Event toward the compact BL-Lac AO 0235+164 at 6.65 GHz. The ESE cloud is
compact; we estimate its diameter between 0.09 and 0.9 AU, and is at a distance
of less than 3.6 kpc. Limits on the angular extent of the ESE cloud imply a
minimum cloud electron density of ~ 4 x 10^3 cm^-3. Based on the amplitude and
timescale of the ESE observed here, we suggest that at least one of the
transients reported by Bower et al. (2007) may be attributed to ESEs.Comment: 11 pages, 2 figure
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