Swashplate feedback control for tilt-rotor aircraft

Changes in angle of attack in system were sensed indirectly by gages which responded to strains induced in wing structure. Output signals were amplified, filtered, and used to activate swashplate actuators. System provided significant reduction in blade loads and desirable changes in hub forces and moments

The Fate of Binaries in the Galactic Center: The Mundane and the Exotic

The Galactic Center (GC) is dominated by the gravity of a super-massive black hole (SMBH), Sagittarius A$^*$, and is suspected to contain a sizable population of binary stars. Such binaries form hierarchical triples with the SMBH, undergoing Eccentric Kozai-Lidov (EKL) evolution, which can lead to high eccentricity excitations for the binary companions' mutual orbit. This effect can lead to stellar collisions or Roche-lobe crossings, as well as orbital shrinking due to tidal dissipation. In this work we investigate the dynamical and stellar evolution of such binary systems, especially with regards to the binaries' post-main-sequence evolution. We find that the majority of binaries (~75%) is eventually separated into single stars, while the remaining binaries (~25%) undergo phases of common-envelope evolution and/or stellar mergers. These objects can produce a number of different exotic outcomes, including rejuvenated stars, G2-like infrared-excess objects, stripped giant stars, Type Ia supernovae (SNe), cataclysmic variables (CVs), symbiotic binaries (SBs), or compact object binaries. We estimate that, within a sphere of 250 Mpc radius, about 7.5 to 15 Type Ia SNe per year should occur in galactic nuclei due to this mechanism, potentially detectable by ZTF and ASAS-SN. Likewise we estimate that, within a sphere of 1 Gpc$^3$ volume, about 10 to 20 compact object binaries form per year that could become gravitational wave sources. Based on results of EKL-driven compact object binary mergers in galactic nuclei by Hoang at al. (2018), this compact object binary formation rate translates to about 15 to 30 events per year detectable by Advanced LIGO.Comment: 8 pages, 3 figures, accepted by Ap

Policy Insights From the EMF 32 Study on U.S. Carbon Tax Scenarios

The Stanford Energy Modeling Forum exercise 32 (EMF 32) used 11 different models to assess emissions, energy, and economic outcomes from a plausible range of economy-wide carbon price policies to reduce carbon dioxide (CO2) emissions in the United States. Here we discuss the most policy-relevant results of the study, mindful of the strengths and weaknesses of current models. Across all models, carbon prices lead to significant reduc- tions in CO2 emissions and conventional pollutants, with the vast majority of the reductions occurring in the electricity sector. Importantly, emissions reductions do not significantly depend on the rebate or tax cut used to return revenues to the economy. Expected economic costs, as modeled by either GDP or welfare, are modest, but vary across models. These costs are offset by benefits from avoided climate damages and health benefits from reductions in conventional air pollution. Using revenues to reduce preexisting capital or labor taxes reduces costs in most models relative to lump-sum rebates, but the size of the cost reductions varies significantly. Devoting at least some revenue to household rebates can significantly reduce adverse impacts on low income households. Carbon prices at $25/ton or even lower levels cause significant shifts away from coal as an energy source with responses of other energy sources highly dependent upon technology cost assumptions. Beyond 2030, we conclude that model uncertainties are too large to make quantitative results useful for near-term policy design. We close by describing recommendations for policymakers on interacting with model results in the future

The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth

We have obtained the first detection of spectral absorption lines in one of the high-velocity stars in the vicinity of the Galaxy's central supermassive black hole. Both Brgamma (2.1661 micron) and He I (2.1126 micron) are seen in absorption in S0-2 with equivalent widths (2.8+-0.3 Ang & 1.7+-0.4 Ang) and an inferred stellar rotational velocity (220+-40 km/s) that are consistent with that of an O8-B0 dwarf, which suggests that it is a massive (~15 Msun), young (<10 Myr) main sequence star. This presents a major challenge to star formation theories, given the strong tidal forces that prevail over all distances reached by S0-2 in its current orbit (130 - 1900 AU) and the difficulty in migrating this star inward during its lifetime from further out where tidal forces should no longer preclude star formation. The radial velocity measurements (-510+-40 km/s) and our reported proper motions for S0-2 strongly constrain its orbit, providing a direct measure of the black hole mass of 4.1(+-0.6)x10^6(Ro/8kpc)^3 Msun. The Keplerian orbit parameters have uncertainities that are reduced by a factor of 2-3 compared to previously reported values and include, for the first time, an independent solution for the dynamical center; this location, while consistent with the nominal infrared position of Sgr A*, is localized to a factor of 5 more precisely (+-2 milli-arcsec). Furthermore, the ambiguity in the inclination of the orbit is resolved with the addition of the radial velocity measurement, indicating that the star is behind the black hole at the time of closest approach and counter-revolving against the Galaxy. With further radial velocity measurements in the next few years, the orbit of S0-2 will provide the most robust estimate of the distance to the Galactic Center.Comment: 14 pages, Latex, Accepted for Publication in ApJ Letter

Dilatonic AdS-Kerr Solution to AdS/CFT Correspondence

We consider the $AdS_5$ solution deformed by a non-constant dilaton interpolating between the standard AdS (UV region) and flat boundary background (IR region). We show that this dilatonic solution can be generalized to the case of a non-flat boundaries provided that the metric of the boundaries satisfies the vacuum Einstein field equations. As an example, we describe the case when the four-dimensional boundaries represent the Kerr space-time.Comment: Latex, 8 pages, v.2: a reference added; v.3: a reference added, and two misprints are improved, v.4: final published version, minor corrections, final part is extended and references adde

Mobility deficit – Rehabilitate, an opportunity for functionality

There are many pathological conditions that cause mobility deficits and that ultimately influence someone’s autonomy.Aims: to evaluate patients with mobility deficits functional status; to implement a Rehabilitation Nursing intervention plan; to monitor health gains through mobility deficits rehabilitation.Conclusion: Early intervention and the implementation of a nursing rehabilitation intervention plan results in health gains (direct or indirect), decreases the risk of developing Pressure Ulcers (PU) and the risk of developing a situation of immobility that affects patients’ autonomy and quality of life