5,018 research outputs found
Spatial Arrangement of Decollements as a Control On The Development of Thrust Faults
I used two-dimensional finite element models to explore different configurations of weak layers in undeformed sedimentary sequences to investigate the occurence of three characteristic types of thrust configurations: ramp-flat; imbricate; and duplex. Two low-friction weak layers in the models were initially horizontal, were separated vertically by 1 km, and were arranged in three different relative positions to each other. When the models were deformed and these weak layers interacted to produce one of the three types of thrust faults as a function of their initial configurations. When the tips of weak layers were separated by a large gap, the models produced imbricate thrusts. When the two weak layers overlapped for a large distance, duplexes formed in the overlapped zone. When the gap or overlap was small, the two weak layers linked up to form a ramp-flat geometry. These results suggest that thrust geometry is highly sensitive to the initial arrangement ofdecollements
Nanomechanical optical fiber with embedded electrodes actuated by joule heating
Nanomechanical optical fibers with metal electrodes embedded in the jacket were fabricated by a multi-material co-draw technique. At the center of the fibers, two glass cores suspended by thin membranes and surrounded by air form a directional coupler that is highly temperature-dependent. We demonstrate optical switching between the two fiber cores by Joule heating of the electrodes with as little as 0.4 W electrical power, thereby demonstrating an electrically actuated all-fiber microelectromechanical system (MEMS). Simulations show that the main mechanism for optical switching is the transverse thermal expansion of the fiber structure
Image Acquisition Rate Control Based on Object State Information in Physical and Image Coordinates
A Luminous X-ray Flare From The Nucleus of The Dormant Bulgeless Spiral Galaxy NGC 247
NGC 247 is a nearby late-type bulgeless spiral galaxy that contains an
inactive nucleus. We report a serendipitous discovery of an X-ray flare from
the galaxy center with a luminosity up to 2*10^39 erg/s in the 0.3-10 keV band
with XMM-Newton. A Chandra observation confirms that the new X-ray source is
spatially coincident with the galaxy nucleus. The XMM-Newton data revealed a
hard power-law spectrum with a spectral break near 3-4 keV, no pulsations on
timescales longer than 150 ms, and a flat power spectrum consistent with
Poisson noise from 1 mHz to nearly 10 Hz. Follow-up observations with Swift
detected a second flux peak followed by a luminosity drop by factor of almost
20. The spectral and temporal behaviors of the nuclear source are well
consistent with the scenario that the flare was due to an outburst of a
low-mass X-ray binary that contains a stellar-mass black hole emitting near its
Eddington limit at the peak. However, it cannot be ruled out that the sudden
brightening in the nucleus was due to accretion onto a possible low-mass
nuclear black hole, fed by a tidally disrupted star or a gas cloud; the MAXI
observations limit the peak luminosity of the flare to less than ~10^43 erg/s,
suggesting that it is either a low mass black hole or an inefficient tidal
disruption event (TDE).Comment: accepted for publication in Ap
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