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Results for “misalignment”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

KELT-9 b’s Asymmetric TESS Transit Caused by Rapid Stellar Rotation and Spin–Orbit Misalignment

KELT-9 b is an ultra-hot Jupiter transiting a rapidly rotating, oblate early-A-type star in a polar orbit. We model the effect of rapid stellar rotation on KELT-9 b’s transit light curve using photometry from the Transiting Exoplanet Survey Satellite to constrain the planet’s true spin–orbit angle and to explore how KELT-9 b may be influenced by stellar gravity darkening. We constrain the host star’s equatorial radius to be 1.089 ± 0.017 times as large as its polar radius and its local surface brightness to vary by ∼38% between its hot poles and cooler equator. We model the stellar oblateness and surface brightness gradient and find that it causes the transit light curve to lack the usual symmetry around the time of minimum light. We take advantage of the light-curve asymmetry to constrain KELT-9 b’s true spin–orbit angle (87{sup ∘}{sub −11{sup ∘+10{sup {sup ∘}}}}), agreeing with Gaudi et al. that KELT-9 b is in a nearly polar orbit. We also apply a gravity-darkening correction to the spectral energy distribution model from Gaudi et al. and find that accounting for rapid rotation gives a better fit to available spectroscopy and yields a more reliable estimate for the star’s polar effective temperature.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1966

Fastener provides for bolt misalignment and quick release of flange

Fastener enables two large flanges to be bolted together without close alignment between the bolt and bolt-hole diameters, and provides for a quick release of one of the flanges under emergency conditions. It contains a nut that is retained by a square head in a recess in one side of the removable flange and by a collar and snap ring on the other side of the flange.

England, C.↗
NASA NTRS1970

Experimental investigation and analysis of two sources of nozzle-thrust misalignment

Asymmetry of nozzle's throat produces oscillatory type net side-force axial profile. Using mean values of localized static pressure and Mach number, scaling laws for flat-plate supersonic flow over protrusion are applied to nozzle expansion cone irregularities to give approximate indication of perturbed-pressure profiles and induced side forces.

Dowdy, M. W.↗
NASA NTRS1973

Synthesis of parameters of a machine set, according to amplitudes of vibration, in the case of coaxial misalignment of shafts

Dynamic synthesis of the coupling parameters permits the building of coaxially aligned connected machines with very small disturbing forces. Considered is the case of two machines connected by a flexible coupling; one machine is installed on shock absorbers with four degrees of freedom. A movement leveling synthesis considers the coaxial nonalignment parameters for the shaft arrangement and determines the optimum coupling rigidity at which the vibration amplitude is at a minimum.

Rondomanskas, M. S.↗
NASA NTRS1979

Misalignment in the radio jets of NGC 6251

The compact nuclear source in NGC 6251 has been observed with VLBI techniques at 2.8 and 13 cm. The source is asymmetric with a bright optically thick core and an optically thin jet. The jet has a small but significant difference in position angle from the outer jet.

Cohen, M. H.↗
NASA NTRS1981

Effects of misalignment on mechanical behavior of metals in creep

Creep tests were conducted by means of a closed loop servocontrolled materials test system. The strain history prior to creep is carefully monitored. Tests were performed for aluminum alloy 6061-O at 150 C and were monitored by a PDP 11/04 minicomputer at a preset constant plastic strain rate prehistory. The results show that the plastic strain rate prior to creep plays a significant role in creep behavior. The endochronic theory of viscoplasticity was applied to describe the observed creep curves. Intrinsic time and strain rate sensitivity function concepts are employed and modified according to the present observation.

Wu, H. C.↗