Miracle-dz/UniFAR-FTUs huggingface dataset:
Stress relaxation of free-standing aluminum beams for microelectromechanical systems applications

We investigated the uniaxial tension and stress relaxation properties of micron-scale Al beams for microelectromechanical systems applications in a piezoactuator-driven test apparatus. Pure aluminum and Al-1.5 at. % titanium free-standing beams were fabricated using micromachining procedures. In the tensile tests, we found the yield strength of the Al beams to be approximately 95 MPa. We also observed a significant strengthening effect in the alloyed samples, which had a yield strength approximately 85% higher than the pure Al samples. In stress relaxation tests, we observed a substantial load-drop (about 56% after 10 min) in the Al films, and we propose here that grain boundary sliding is responsible for this relaxation. By comparison, the relaxation of the Ti-alloyed samples was only 15%. We believe that this difference results from the Al3Ti precipitates that form at the Al grain boundaries in the alloy samples.
Convective-core Overshoot and Suppression of Oscillations: Constraints from Red Giants in NGC 6811

Using data from the NASA spacecraft Kepler, we study solar-like oscillations in red giant stars in the open cluster NGC 6811. We determine oscillation frequencies, frequency separations, period spacings of mixed modes, and mode visibilities for eight cluster giants. The oscillation parameters show that these stars are helium-core-burning red giants. The eight stars form two groups with very different oscillation power spectra; the four stars with the lowest Δν values display rich sets of mixed l = 1 modes, while this is not the case for the four stars with higher Δν. For the four stars with lowest Δν, we determine the asymptotic period spacing of the mixed modes, ΔP, which together with the masses we derive for all eight stars suggest that they belong to the so-called secondary clump. Based on the global oscillation parameters, we present initial theoretical stellar modeling that indicates that we can constrain convective-core overshoot on the main sequence and in the helium-burning phase for these ∼2 M⊙ stars. Finally, our results indicate less mode suppression than predicted by recent theories for magnetic suppression of certain oscillation modes in red giants.
Rapidly rotating, post-Newtonian neutron stars

Equilibrium models of rapidly rotating neutron stars supported by nonrelativistic, degenerate neutrons are examined in the Parametrized Post-Newtonian (PPN) framework. An energy variational principle is employed to analyze the effects of rapid rotation and relativistic gravity on the mass-density relation and maximum mass of neutron stars. The fractional increase in the mass of stable, equilibrium configurations due to rotation is smaller for neutron stars than for white dwarfs, a consequence of the destabilizing effects of post-Newtonian gravity. Currently viable conservative theories of gravity with high values of the PPN parameter . beta. can have significantly larger masses than predicted by general relativity. Also discussed qualitatively is the evolution of transient, rotating compact objects called ''fizzlers,'' which contract to form pulsars and black holes on secular (gravitational radiation) time scales. (AIP)
The non-linear fluid dynamics of a warped accretion disc

The dynamics of a viscous accretion disc subject to a slowly varying warp of large amplitude is considered. Attention is restricted to discs in which self-gravitation is negligible, and to the generic case in which the resonant wave propagation found in inviscid Keplerian discs does not occur. The equations of fluid dynamics are derived in a coordinate system that follows the principal warping motion of the disc. They are reduced using asymptotic methods for thin discs, and solved to extract the equation governing the warp. In general, this is a wave equation of parabolic type with non-linear dispersion and diffusion, which describes fully non-linear bending waves. This method generalizes the linear theory of Papaloizou & Pringle to allow for an arbitrary rotation law, and extends it into the non-linear domain, where it connects with a generalized version of the theory of Pringle. The astrophysical implications of this analysis are discussed briefly.
Scaled Brownian motion with renewal resetting.

We investigate an intermittent stochastic process in which the diffusive motion with time-dependent diffusion coefficient D(t)∼t^{α-1} with α>0 (scaled Brownian motion) is stochastically reset to its initial position, and starts anew. In the present work we discuss the situation in which the memory on the value of the diffusion coefficient at a resetting time is erased, so that the whole process is a fully renewal one. The situation when the resetting of the coordinate does not affect the diffusion coefficient's time dependence is considered in the other work of this series [A. S. Bodrova et al., Phys. Rev. E 100, 012119 (2019)10.1103/PhysRevE.100. 012119]. We show that the properties of the probability densities in such processes (erasing or retaining the memory on the diffusion coefficient) are vastly different. In addition we discuss the first-passage properties of the scaled Brownian motion with renewal resetting and consider the dependence of the efficiency of search on the parameters of the process.
The Ultraviolet Luminosity Function of GALEX Galaxies at Photometric Redshifts between 0.07 and 0.25

We present measurements of the UV galaxy luminosity function and the evolution of luminosity density from Galaxy Evolution Explorer (GALEX) observations matched to the Sloan Digital Sky Survey (SDSS). We analyze galaxies in the Medium Imaging Survey overlapping the SDSS First Data Release, with a total coverage of 44 deg2. Using the combined GALEX + SDSS photometry, we compute photometric redshifts and study the luminosity function in three redshift shells between z = 0.07 and 0.25. The Schechter function fits indicate that the faint-end slope α is consistent with -1.1 at all redshifts, but the characteristic UV luminosity M* brightens by 0.2 mag from z = 0.07 to 0.25. In the lowest redshift bin, early- and late-type galaxies are studied separately, and we confirm that red galaxies tend to be brighter and have a shallower slope α than blue ones. The derived luminosity densities are consistent with other GALEX results based on a local spectroscopic sample from the Two-Degree Field, and the evolution follows the trend reported by deeper studies.
Reorganization of a 2D disordered granular medium due to a small local cyclic perturbation

We measure experimentally the rearrangements due to a small localized cyclic displacement applied to a packing of rigid grains under gravity in a 2D geometry. We analyze the evolution of the response to this perturbation by considering the individual particle displacement and the coarse grained displacement field, as well as the mean packing fraction and coordination number. We find that the displacement response is rather long ranged, and evolves considerably with the number of cycles. We show that a small difference in the preparation method (induced by tapping the container) leads to a significant modification in the response though the packing fraction changes are minute. Not only the initial response but also its further evolution change with preparation, demonstrating that the system still retains a memory of the initial preparation after many cycles. Nevertheless, after a sufficient number of cycles, the displacement response for both preparation methods converges to a nearly radial field with a 1/r decay from the perturbation source. The observed differences between the preparation methods seem to be related to the changes in the coordination number (which is more sensitive to the evolution of the packing than the packing fraction). Specifically, it may be understood as an effect of the breaking of local arches, which affects the lateral transmission of forces.
Mass, angular momentum and thermodynamics in four-dimensional Kerr-AdS black holes

In this paper, the connection between the Lorentz-covariant counterterms that regularize the four-dimensional AdS gravity action and topological invariants is explored. It is shown that demanding the spacetime to have a negative constant curvature in the asymptotic region permits the explicit construction of such series of boundary terms. The orthonormal frame is adapted to appropriately describe the boundary geometry and, as a result, the boundary term can be expressed as a functional of the boundary metric, extrinsic curvature and intrinsic curvature. This choice also allows to write down the background-independent Noether charges associated to asymptotic symmetries in standard tensorial formalism. The absence of the Gibbons-Hawking term is a consequence of an action principle based on a boundary condition different than Dirichlet on the metric. This argument makes plausible the idea of regarding this approach as an alternative regularization scheme for AdS gravity in all even dimensions, different than the standard counterterms prescription. As an illustration of the finiteness of the charges and the euclidean action in this framework, the conserved quantities and black hole entropy for four-dimensional Kerr-AdS are computed.
Core Radio and Optical Emission in the Nuclei of Nearby FR I Radio Galaxies

In this paper we analyze the relation between radio, optical continuum and Hα+[N II] emission from the cores of a sample of 21 nearby Fanaroff and Riley type I galaxies as observed with the VLBA and HST. The emission arises inside the inner tens of parsecs of the galaxies. Core radio emission is observed in 19/20 galaxies, optical core continuum emission is detected in 12/21 galaxies and Hα+[N II] core emission is detected in 20/21 galaxies. We confirm the recently detected linear correlation between radio and optical core emission in FR I galaxies and show that both core emissions also correlate with central Hα+[N II] emission. The tight correlations between radio, optical, and Hα+[N II] core emission constrain the bulk Lorentz factor to γ ∼ 2–5 and γ ≲ 2 for a continuous jet and a jet consisting of discrete blobs, respectively, assuming jet-viewing angles in the range 30°–90°. Radio and optical core emissions are likely to be synchrotron radiation from the inner jet, possibly with a significant contribution from emission by an accretion disk and/or flow. Elliptical galaxies with LINER nuclei without large-scale radio jets seem to follow the core emission correlations found in FR I galaxies. This suggests that the central engines could be very similar for the two classes of active galactic nuclei.
The Evolving Radio Photospheres of Long-period Variable Stars

Observations with the Karl G. Jansky Very Large Array at 46 GHz (λ ≈ 7 mm) have been used to measure the size and shape of the radio photospheres of four long-period variable stars: R Leonis (R Leo), IRC+10216 (CW Leonis), χ Cygni (χ Cyg), and W Hydrae (W Hya). The shapes of the stars range from nearly round to ellipticities of ∼0.15. Comparisons with observations taken several years earlier show that the photospheric parameters (mean diameter, shape, and/or flux density) of each of the stars have changed over time. Evidence for brightness asymmetries and nonuniformities across the radio surfaces is also seen in the visibility domain and in images obtained using a sparse-modeling image reconstruction technique. These trends may be explained as manifestations of large-scale irregular convective flows on the stellar surface, although effects from nonradial pulsations cannot be excluded. Our data also allow a new evaluation of the proper motion of IRC+10216. Our measurement is in agreement with previous values obtained from radio-wavelength measurements, and we find no evidence of statistically significant astrometric perturbations from a binary companion.
d- and p-Wave superconductivity mediated by spin fluctuations in two- and three-dimensional single-band repulsive Hubbard model

We have systematically studied superconducting instabilities in the repulsive Hubbard model for d -wave and p -wave pairing in various 2D and 3D lattices. Using fluctuation exchange approximation, we consider 3D face centered cubic lattice, 3D body centered cubic lattice, 3D simple cubic lattice, 2D square lattice and 2D triangular lattice, where either strong ferro- or antiferromagnetic spin fluctuations are present. We show that (i) d -wave instability mediated by antiferromagnetic spin fluctuations is stronger than p -wave instability mediated by ferromagnetic spin fluctuations both in 2D and 3D, and (ii) d -wave instability in 2D is much stronger than that in 3D. These amount that the “best" situation is the antiferromagnetic-fluctuation mediated in 2D as far as the single-band Hubbard model on ordinary lattices are concerned.
Expectation values of twist fields and universal entanglement saturation of the free massive boson

The evaluation of vacuum expectation values (VEVs) in massive integrable quantum field theory (QFT) is a nontrivial renormalization-group ‘connection problem’—relating large and short distance asymptotics—and is in general unsolved. This is particularly relevant in the context of entanglement entropy, where VEVs of branch-point twist fields give universal saturation predictions. We propose a new method to compute VEVs of twist fields associated to continuous symmetries in QFT. The method is based on a differential equation in the continuous symmetry parameter, and gives VEVs as infinite form-factor series which truncate at two-particle level in free QFT. We verify the method by studying U(1) twist fields in free models, which are simply related to the branch-point twist fields. We provide the first exact formulae for the VEVs of such fields in the massive uncompactified free boson model, checking against an independent calculation based on angular quantization. We show that logarithmic terms, overlooked in the original work of Callan and Wilczek (1994 Phys. Lett. B 333 55–61), appear both in the massless and in the massive situations. This implies that, in agreement with numerical form-factor observations by Bianchini and Castro-Alvaredo (2016 Nucl. Phys. B 913 879–911), the standard power-law short-distance behavior is corrected by a logarithmic factor. We discuss how this gives universal formulae for the saturation of entanglement entropy of a single interval in near-critical harmonic chains, including loglog corrections.
Momentum Flux by Lines of Cumulonimbus over the Tropical Oceans

Abstract Examination of aircraft and rawinsonde data gathered in nine tropical mesoscale convective line cases indicates that all but two lines systematically increased front-to-rear momentum at heights greater than about 4 km, and rear-to-front momentum at lower levels, where “front” is defined as the direction toward which the line is moving. The convective lines were characterized by a leading 10–20 km wide band of convective clouds, and a trailing region of stratiform cloudiness. Most wore “propagating” lines, moving into the wind at all levels. Consistent with mixing-length theory, the vertical transport of the horizontal wind component parallel to the lines was down the vertical gradient of the component, resulting in a decrease of its vertical shear. Smaller, more random cloud groups and the upper portions of a convective line with isolated towers transported both components of horizontal momentum downgradient. Normalization of the vertical flux of horizontal momentum normal to the line (u′¯w′¯) su.
The B-spline R-matrix method for atomic processes: application to atomic structure, electron collisions and photoionization

The basic ideas of the B-spline R-matrix (BSR) approach are reviewed, and the use of the method is illustrated with a variety of applications to atomic structure, electron–atom collisions and photo-induced processes. Special emphasis is placed on complex, open-shell targets, for which the method has proven very successful in reproducing, for example, a wealth of near-threshold resonance structures. Recent extensions to a fully relativistic framework and intermediate energies have allowed for an accurate treatment of heavy targets as well as a fully nonperturbative scheme for electron-impact ionization. Finally, field-free BSR Hamiltonian and electric dipole matrices can be employed in the time-dependent treatment of intense short-pulse laser–atom interactions.
Transition and Turbulence Phenomena in Supersonic Wakes of Wedges

At supersonic speeds the wake of a blunt body may be divided into an inner viscous wake stemming from the body boundary layers and an outer “inviscid” wake produced by the bow shock. In such wakes, as in the wake of a cylinder, at low Reynolds numbers the onset of transition occurs thousands of diameters downstream of the body in the outer, shock-induced wake. As the Reynolds number is increased, transition occurs in the inner wake. For the same Mach number and at high Reynolds numbers transition on the wake of a wedge occurs further downstream than in the case of a cylinder, but the slender body transition curve crosses the blunt body transition curve. The question arises, where does transition occur in slender body wakes as the Reynolds number is decreased further? What effect does the much weaker outer shock-induced wake have on transition and, is the outer wake unstable enough to become turbulent?
Pulsar wind nebulae created by fast-moving pulsars

We review multiwavelength properties of pulsar wind nebulae created by supersonically moving pulsars and the effects of pulsar motion on the pulsar wind nebulae morphologies and the ambient medium. Supersonic pulsar wind nebulae are characterized by bow-shaped shocks around the pulsar and/or cometary tails filled with the shocked pulsar wind. In the past several years significant advances in supersonic pulsar wind nebula studies have been made in deep observations with the Chandra and XMM-Newton X-ray observatories and the Hubble Space Telescope. In particular, these observations have revealed very diverse supersonic pulsar wind nebula morphologies in the pulsar vicinity, different spectral behaviours of long pulsar tails, the presence of puzzling outflows misaligned with the pulsar velocity and far-UV bow shocks. Here we review the current observational status focusing on recent developments and their implications.
Microphysical properties of tropical anvil cirrus observed during ACTIVE: a statistical analysis

The effect of cirrus cloud on radiative transfer depends on its microphysical properties. The water content and number concentrations of ice particles in tropical anvil cirrus measured during the ACTIVE (Aerosol and Chemical Transport in Tropical Convection) field campaign (from November 2005 to February 2006 in Darwin area, Australia) are analyzed. Some advanced particle probes are utilized during this campaign, including Cloud Imaging Probe (CIP) and Cloud Particle Imager (CPI). A statistical analysis of the fifteen cases (only the slow phase of anvil cirrus with the height ranging from 9.7 to 14.9 km and temperature ranging from -70.4°C to -30.0°C, are considered) shows that the typical value of ice water content (IWC) is 10-2 g m-3, and the number concentrations of ice particles measured by CIP (>100μm) and CPI (>5μm), are 101 and 102 L-1, respectively. The changes in median of IWC in anvil cirri with temperature (or altitude) are examined and compared among different phases of Australian monsoon.
Advanced scenarios for ITER operation

In thermonuclear fusion research using magnetic confinement, the tokamak is the leading candidate for achieving the conditions required for a reactor. An international experiment, ITER, is proposed as the next essential and critical step on the path to demonstrating the scientific and technological feasibility of fusion energy. ITER is to produce and study plasmas dominated by self-heating. This would give unique opportunities to explore, in reactor relevant conditions, the physics of α-particle heating, plasma turbulence and turbulent transport, stability limits to the plasma pressure and exhaust of power and particles. Important new results obtained in experiments, theory and modelling, enable an improved understanding of the physical processes occurring in tokamak plasmas and give enhanced confidence that ITER will achieve its goals. In particular, progress has been made in research to raise the performance of tokamaks, aimed to extend the discharge pulse length towards steady-state operation (advanced scenarios). Standard tokamak discharges have a current density increasing monotonically towards the centre of the plasma. Advanced scenarios, on the other hand, use a modified current density profile. Different advanced scenarios range from (i) plasmas that sustain a central region with a flat current density profile (zero magnetic shear), capable of operating stationary at high plasma pressure, to (ii) discharges with an off-axis maximum of the current density profile (reversed magnetic shear in the core), able to form internal transport barriers, to increase the confinement of the plasma. The physics of advanced tokamak discharges is described, together with an overview of recent results from different tokamak experiments. International collaboration between experiments aims to provide a better understanding, control and optimization of these plasmas. The ability to explore advanced scenarios in ITER is very desirable, in order to verify the results obtained in experiments today and to demonstrate the potential to significantly increase the economic attractiveness of the tokamak.
BVRcIc OBSERVATIONS AND ANALYSES OF THE DWARF DETACHED BINARY V1043 CASSIOPEIA AND A COMMENT ON PRECONTACT W UMa'S

Complete Bessel BVRcIc light curves of V1043 Cassiopeia [2MASS J00371195+5301324, Mis V1292, USNO−A2.0 1425−00875743, α(2000) = 00h37m11. ˢ95, δ(2000) = +53°01′32. ″5] are analyzed. The system is a member of the small group of pre-contact W UMa binaries (PCWBs). Its light curve has the appearance of an Algol (EA) light curve, however it is made up of dwarf solar type components in a detached mode with a period of only 0.6616 days. The analysis includes a period study, an improved ephemeris, a mass ratio search, and a simultaneous BVRcIc Wilson–Devinney solution. We document about 20 other PCWBs given in the literature. Several have RS CVn-like properties.
Photospheric Emission from Variable Engine Gamma-Ray Burst Simulations

By coupling radiation transfer calculations to hydrodynamic simulations, there have been major advancements in understanding the long gamma-ray burst (LGRB) prompt emission. Building upon these achievements, we present an analysis of photospheric emission acquired by using the Monte Carlo Radiation Transfer (MCRaT) code on hydrodynamic simulations with variable jet profiles. MCRaT propagates and Compton-scatters individual photons that have been injected into the collimated outflow in order to produce synthetic light curves and spectra. These light curves and spectra allow us to compare our results to LGRB observational data. We find excellent agreement between our fitted time-resolved β parameters and those that are observed. Additionally, our simulations show that photospheric emission, under certain conditions, is able to create the observationally expected Band α parameter. Finally, we show that the simulations are consistent with the Golenetskii correlation but exhibit some strain with the Amati and Yonetoku correlations.
Calibration strategy and optics for ARGOS at the LBT

Effective calibration procedures play an important role for the efficiency and performance of astronomical instrumentation. We report on the calibration scheme for ARGOS, the Laser Guide Star (LGS) facility at the LBT. An artificial light source is used to feign the real laser beacons and perform extensive testing of the system, independent of the time of day and weather conditions, thereby greatly enhancing the time available for engineering. Fibre optics and computer generated holograms (CGHs) are used to generate the necessary wavefront. We present the optomechanical design, and discuss the expected accuracy, as well as tolerances in assembly and alignment.