Explicit soliton-black hole correspondence for static configurations

We construct an explicit map that transforms static, generalized sine-Gordon metrics to black hole type metrics. This, in particular, provides for a further description of the Cadoni correspondence (which extends the Gegenberg-Kunstatter correspondence) of soliton solutions and extremal black hole solutions in 2D dilaton gravity.Comment: Submitted to Phys Rev D, 7 pages, no figure

Bidirectional torque filter eliminates backlash

Two elastic springs connecting a hub and two spur gears absorb bidirectional step torque differentials and provide antibacklash characteristics between input and output shafts. This device is used in precise control systems

Bidirectional step torque filter with zero backlash characteristic Patent

Gearing system for eliminating backlash and filtering input torque fluctuations from high inertia loa

Development of the dry tape battery concept Quarterly report no. 4, 9 Mar. - 9 Jun. 1966

Aqueous and nonqueous electrolytic actions, and energy density measurements for dry tape batter

The administration of research. An interpretive summary of the Proceedings of the National Conference on the Administration of Research, 1947-1964

Research management and administration - summary of conference proceeding

Monitoring corn harvest progress from ERTS-1, southern Finney County, Kansas

The author has identified the following significant results. Comparison of ERTS-1 imagery of three dates reveals that corn harvesting is detectable by observing tonal change associated with the change from photosynthetically active plants to bare ground

Flux cancellation and the evolution of the eruptive filament of 2011 June 7

We investigate whether flux cancellation is responsible for the formation of a very massive filament resulting in the spectacular 2011 June 7 eruption. We analyse and quantify the amount of flux cancellation that occurs in NOAA AR 11226 and its two neighbouring ARs (11227 & 11233) using line-of-sight magnetograms from the Heliospheric Magnetic Imager. During a 3.6-day period building up to the filament eruption, 1.7 x 10^21 Mx, 21% of AR 11226's maximum magnetic flux, was cancelled along the polarity inversion line (PIL) where the filament formed. If the flux cancellation continued at the same rate up until the eruption then up to 2.8 x 10^21 Mx (34% of the AR flux) may have been built into the magnetic configuration that contains the filament plasma. The large flux cancellation rate is due to an unusual motion of the positive polarity sunspot, which splits, with the largest section moving rapidly towards the PIL. This motion compresses the negative polarity and leads to the formation of an orphan penumbra where one end of the filament is rooted. Dense plasma threads above the orphan penumbra build into the filament, extending its length, and presumably injecting material into it. We conclude that the exceptionally strong flux cancellation in AR 11226 played a significant role in the formation of its unusually massive filament. In addition, the presence and coherent evolution of bald patches in the vector magnetic field along the PIL suggests that the magnetic field configuration supporting the filament material is that of a flux rope.Comment: 18 pages, 7 figures. Submitted to ApJ in December 2015, accepted in June 201

Pixelated Lenses and H_0 from Time-delay QSOs

Observed time delays between images of a lensed QSO lead to the determination of the Hubble constant by Refsdal's method, provided the mass distribution in the lensing galaxy is reasonably well known. Since the two or four QSO images usually observed are woefully inadequate by themselves to provide a unique reconstruction of the galaxy mass, most previous reconstructions have been limited to simple parameterized models, which may lead to large systematic errors in the derived H_0 by failing to consider enough possibilities for the mass distribution of the lens. We use non-parametric modeling of galaxy lenses to better explore physically plausible but not overly constrained galaxy mass maps, all of which reproduce the lensing observables exactly, and derive the corresponding distribution of H_0's. Blind tests - where one of us simulated galaxy lenses, lensing observables, and a value for H_0, and the other applied our modeling technique to estimate H_0 indicate that our procedure is reliable. For four simulated lensed QSOs the distribution of inferred H_0 have an uncertainty of \simeq 10% at 90% confidence. Application to published observations of the two best constrained time-delay lenses, PG1115+080 and B1608+656, yields H_0=61 +/- 11 km/s/Mpc at 68% confidence and 61 +/- 18 km/s/Mpc at 90% confidence.Comment: 27 pages, including 17 figs, LaTeX; accepted to A

A Bayesian method for detecting stellar flares

We present a Bayesian-odds-ratio-based algorithm for detecting stellar flares in light curve data. We assume flares are described by a model in which there is a rapid rise with a half-Gaussian profile, followed by an exponential decay. Our signal model also contains a polynomial background model. This is required to fit underlying light curve variations that are expected in the data, which could otherwise partially mimic a flare. We characterise the false alarm probability and efficiency of this method and compare it with a simpler thresholding method based on that used in Walkowicz et al (2011). We find our method has a significant increase in detection efficiency for low signal-to-noise ratio (S/N) flares. For a conservative false alarm probability our method can detect 95% of flares with S/N less than ~20, as compared to S/N of ~25 for the simpler method. As an example we have applied our method to a selection of stars in Kepler Quarter 1 data. The method finds 687 flaring stars with a total of 1873 flares after vetos have been applied. For these flares we have characterised their durations and and signal-to-noise ratios.Comment: Accepted for MNRAS. The code used for the analysis can be found at https://github.com/BayesFlare/bayesflare/releases/tag/v1.0.

Research in and application of state variable feedback design of guidance control systems for aerospace vehicles Progress report

Weighted least squares parameter estimation, Kalman filter, and random search problems for aerospace guidance control system desig