Miracle-dz/UniFAR-FTUs huggingface dataset:
Calibration of 3D scan trajectories for an industrial computed tomography setup with 6-DOF object manipulator system using a single sphere

In industrial x-ray computed tomography (CT), the application of more complex scan paths in comparison to the typical circular trajectory ( 360∘ rotation of the measurement object) can extend the potential of CT. One way to enable such 3D scan trajectories is to use a 6-degrees-of-freedom (DOF) object manipulator system. In our case, a hexapod is mounted on top of the rotary table of a commercial CT scanner. This allows for adaptive tilting of the measurement object during the scan. For high accuracy, the geometry calibration of such setups is typically done using the x-ray projections of a calibrated multi-sphere object. Contrary to this, here, we demonstrate a procedure that is based on only a single sphere and can therefore experimentally be implemented with low effort. Using the intrinsic geometry parameters of the CT device as prior information, the hexapod coordinate system with respect to the CT machine coordinate system is determined by means of a one-step optimization approach. The resulting parameters are used to calculate projection matrices that enable the volume reconstruction for 3D scan trajectories. The method is validated using simulated x-ray images and experimental investigations including dimensional measurements. For the used setup, geometric measurement results for 3D scan trajectories that are calibrated with the presented method show in sum increased errors compared to the circular scans. A limited pose accuracy of the manipulator system is discussed as a potential cause. The results nevertheless indicate that the presented method is generally feasible for dimensional CT measurements provided that the pose accuracy is sufficient. The calibration procedure can therefore be a low-cost and easier to implement alternative compared to trajectory calibration methods based on multi-sphere objects, but with a tendency towards lower measurement accuracy. The methodology can in principle be transferred to different setups with 6-DOF manipulator systems, e.g. C-arm CT devices with a robot arm.
The role of axisymmetric flow configuration in the estimation of the analogue surface gravity and related Hawking like temperature

We investigate the salient features of the acoustic geometry corresponding to the axially symmetric accretion of dissipationless inhomogeneous fluid onto a non-rotating astrophysical black hole under the influence of a generalized pseudo-Schwarzschild gravitational potential. For a few chosen flow configurations, we determine the location of the acoustic horizon and calculate analytically the corresponding analogue surface gravity κ and the associated analogue Hawking temperature TAH. We study the dependence of κ on various boundary conditions and geometry governing the dynamic and thermodynamic properties of the background flow.
Breakdown of the Thomas Fermi approximation for polarized Fermi gases

We use Bogoliubov de-Gennes theory to show that the commonly used Thomas-Fermi approximation (TFA) can fail in describing polarized unitary gases in anisotropic harmonic traps. We find a magnetized superfluid region inside the trap, with order parameter oscillations, even though there is no such stable bulk phase. This leads to magnetization profiles that deviate from contours of constant potential energy. We determine how this violation scales with trap anisotropy and number of particles, and show that we are able to account for important differences between the MIT and Rice experiments.
Dangerous Play in an Age of Technofinance: From the GameStop Hunger Games to the Capitol Hill Jamboree

ABSTRACT:In this paper we explore one dimension of the contemporary cultural politics that gives rise to reactionary formations and movements: the desire for a kind of dangerous play within a financialized world where most people feel trapped in a game they can’t win. We take up three interwoven phenomena from the recent past in the United States, though with implications beyond that context: (a) the GameStop stock-buying frenzy of early 202l, (b) the storming of the US Capitol building on January 6 of that year, and (c) the dramatic rise in popularity of the QAnon conspiracy fantasy that appeared in 2017 and gained significant influence since. By locating these complex participatory phenomena in the context of digitized financialization characterized by gamification, alienation and profound inequalities, we supplement efforts to understand today’s reactionary imagination. We argue that all three might be seen as, in part, forms of dangerous play that both emerge from, rebel against and also, contradictorily, help to reproduce or entrench dominant inequalities. Hence those who wish to counter these reactionary tendencies or propose more radical responses cannot limit themselves to critique; they must also contend with what animates these forms of alienated play. RÉSUMÉ:Nous explorons dans cet article une dimension de la culture politique contemporaine qui donne lieu à des formations et des mouvements réactionnaires : le désir pour une certaine forme de jeu dangereux, dans un monde financiarisé où la plupart des gens se sentent prisonniers d’une partie qu’ils et elles ne peuvent pas gagner. Les trois phénomènes interreliés que nous étudions sont choisis dans l’histoire récente des États-Unis, bien que leurs conséquences s’étendent au-delà : (a) les achats frénétiques d’actions de GameStop, au début de 2021, (b) l’assaut du Capitol, à Washington, le 6 janvier de cette même année, et (c) la spectaculaire augmentation en popularité de la fiction conspirationniste de QAnon, apparue en 2017 et dont l’influence, depuis, est devenue considérable. En situant ces phénomènes participatifs complexes dans le contexte de la financiarisation numérique caractérisée par la ludification, l’aliénation et de profondes inégalités, nous aidons à comprendre l’imaginaire réactionnaire d’aujourd’hui. Nous soutenons que ces trois évènements peuvent se comprendre, en partie, comme des formes de jeu dangereux – jeu qui nait des inégalités dominantes, qui se rebelle contre elles et qui, de manière contradictoire, contribue à leur reproduction ou leur consolidation. Par conséquent, si l’on entend contrer ces tendances réactionnaires ou leur opposer des réactions plus radicales, on ne saurait se contenter de critiquer ; il faut reconnaitre ce qui anime ces formes de jeu aliéné.
GROUND-BASED MULTIWAVELENGTH OBSERVATIONS OF COMET 103P/HARTLEY 2

The Jupiter-family comet 103P/Hartley 2 (103P) was the target of the NASA EPOXI mission. In support of this mission, we conducted observations from radio to submillimeter wavelengths of comet 103P in the three weeks preceding the spacecraft rendezvous on UT 2010 November 4.58. This time period included the passage at perihelion and the closest approach of the comet to the Earth. Here, we report detections of HCN, H2CO, CS, and OH and upper limits for HNC and DCN toward 103P using the Arizona Radio Observatory Kitt Peak 12 m telescope (ARO 12 m) and submillimeter telescope (SMT), the James Clerk Maxwell Telescope (JCMT), and the Green Bank Telescope (GBT). The water production rate, = (0.67–1.07) × 1028 s−1, was determined from the GBT OH data. From the average abundance ratios of HCN and H2CO relative to water (0.13 ± 0.03% and 0.14 ± 0.03%, respectively), we conclude that H2CO is depleted and HCN is normal with respect to typically observed cometary mixing ratios. However, the abundance ratio of HCN with water shows a large diversity with time. Using the JCMT data, we measured an upper limit for the DCN/HCN ratio <0.01. Consecutive observations of ortho-H2CO and para-H2CO on November 2 (from data obtained at the JCMT) allowed us to derive an ortho:para ratio (OPR) of ≈2.12 ± 0.59 (1σ), corresponding to Tspin > 8 K (2σ).
WIYN OPEN CLUSTER STUDY. XXXII. STELLAR RADIAL VELOCITIES IN THE OLD OPEN CLUSTER NGC 188

We present the results of our ongoing radial-velocity (RV) survey of the old (7 Gyr) open cluster NGC 188. Our WIYN 3.5 m data set spans a time baseline of 11 years, a magnitude range of 12 ⩽ V ⩽ 16.5 (1.18–0.94 M☉), and a 1° diameter region on the sky. With the addition of a Domain Astrophysical Observatory data set we extend our bright limit to V = 10.8 and, for some stars, extend our time baseline to 35 years. Our magnitude limits include solar-mass main-sequence stars, subgiants, giants, and blue stragglers (BSs), and our spatial coverage extends radially to 17 pc (∼13 core radii). For the WIYN data we present a detailed description of our data reduction process and a thorough analysis of our measurement precision of 0.4 km s−1 for narrow-lined stars. We have measured radial velocities for 1046 stars in the direction of NGC 188, and have calculated RV membership probabilities for stars with ⩾3 measurements, finding 473 to be likely cluster members. We detect 124 velocity-variable cluster members, all of which are likely to be dynamically hard-binary stars. Using our single member stars, we find an average cluster radial velocity of −42.36 ± 0.04 km s−1. We use our precise RV and proper-motion membership data to greatly reduce field-star contamination in our cleaned color–magnitude diagram, from which we identify six stars of note that lie far from a standard single-star isochrone. We present a detailed study of the spatial distribution of cluster-member populations, and find the binaries to be centrally concentrated, providing evidence for the presence of mass segregation in NGC 188. We observe the BSs to populate a bimodal spatial distribution that is not centrally concentrated, suggesting that we may be observing two populations of BSs in NGC 188, including a centrally concentrated distribution as well as a halo population. Finally, we find NGC 188 to have a global RV dispersion of 0.64 ± 0.04 km s−1, which may be inflated by up to 0.23 km s−1 from unresolved binaries. When corrected for unresolved binaries, the NGC 188 RV dispersion has a nearly isothermal radial distribution. We use this mean-corrected velocity dispersion to derive a virial mass of 2300 ± 460 M☉ .
Possible physical realizations of the Tolman VII solution

The Tolman VII solution (an exact static spherically symmetric perfect fluid solution) to the Einstein equations is reexamined, and a closed form equation of state (EOS) is deduced for the first time. This EOS allows further analysis leading to a viable model for compact stars to be obtained. Explicit application of causality conditions places further constraints on the model, and recent measurements of masses and radii of neutron stars prove to be within the predictions of the model. It is found that the adiabatic index ${\gamma} \geq 2$, and self-bound crust solutions are not excluded. The solution is also shown to obey known stability criteria. It is argued that this solution provides realistic limits on models of compact stars.
Chemical evolution of Local Group dwarf galaxies in a cosmological context - I. A new modelling approach and its application to the Sculptor dwarf spheroidal galaxy

We present a new approach for chemical evolution modelling, specifically designed to investigate the chemical properties of dwarf galaxies in a full co smological framework. In particular, we focus on the Sculptor dwarf spheroidal galaxy, for which a wealth of observational data exists, as a test bed for our model. We select four candid ate Sculptor-like galaxies from the satellite galaxy catalogue generated by implementation of a version of the Munich semianalytic model for galaxy formation on the level 2 Aquarius dark matter simulations and use the mass assembly and star formation histories predicted fo r these four systems as an input for the chemical evolution code. We follow explicitly the evolution of several chemical elements, both in the cold gas out of which the stars form and in the hot medium residing in the halo. We take into account in detail the lifetimes of star s of different initial masses, the distribution of the delay times for type Ia supernova explos ions and the dependency of the stellar yields from the initial metallicity of the stars. We allow large fractions of metals to be deposited into the hot phase, either directly as stars die or through reheated gas flows powered by supernova explosions. We find that, in order to reproduce b oth the observed metallicity distribution function and the observed abundance ratios of long-lived stars of Sculptor, large fractions of the reheated metals must never re-enter region s of active star formation. With this prescription, all the four analogues to the Sculptor dwarf s pheroidal galaxy extracted from the simulated satellites catalogue on the basis of luminosi ty and stellar population ages are found to reasonably match the detailed chemical properties of real Sculptor stars. However, all model galaxies do severely underestimate the fraction o f very metal-poor stars observed in Sculptor. Our analysis thus sets further constraints on t he semi-analytical models and, at large, on possible metal enrichment scenarios for the Sculp tor dwarf spheroidal galaxy.
THE OUTER LIMITS OF THE M31 SYSTEM: KINEMATICS OF THE DWARF GALAXY SATELLITES AND XXVIII & AND XXIX

We present Keck/DEIMOS spectroscopy of resolved stars in the M31 satellites And XXVIII and And XXIX. We show that these are likely self-bound galaxies based on 18 and 24 members in And XXVIII and And XXIX, respectively. And XXVIII has a systemic velocity of −331.1 ± 1.8 km s−1 and a velocity dispersion of 4.9 ± 1.6 km s−1, implying a mass-to-light ratio (within r1/2) of ∼44 ± 41. And XXIX has a systemic velocity of −194.4 ± 1.5 km s−1 and velocity dispersion of 5.7 ± 1.2 km s−1, implying a mass-to-light ratio (within r1/2) of ∼124 ± 72. The internal kinematics and implied masses of And XXVIII and And XXIX are similar to those of dwarf spheroidals (dSphs) of comparable luminosities, implying that these objects are dark-matter-dominated dwarf galaxies. Despite the large projected distances from their host (380 and 188 kpc), the kinematics of these dSph suggest that they are bound M31 satellites.
Depth of C(X)-modules

Abstract It is shown that the depth of every module over C(X), the ring of all real valued continuous functions on a topological space X, is at most 1. This result is proved for modules over rings of a much more general class than the rings of continuous functions. It also turns out that many facts in the literature concerning the depths of C(X), their sub-algebras, and ideals are consequences of this main result. Some known results are generalized and some applications are given.
Lifetime of the A(v ' = 0) state and Franck-Condon factor of the A-X(0-0) transition of CaF measured by the saturation of laser-induced fluorescence

We describe a method for determining the radiative decay properties of a molecule by studying the saturation of laser-induced fluorescence and the associated power broadening of spectral lines. The fluorescence saturates because the molecules decay to states that are not resonant with the laser. The amplitudes and widths of two hyperfine components of a spectral line are measured over a range of laser intensities and the results compared to a model of the laser-molecule interaction. Using this method we measure the lifetime of the $A({v}^{\ensuremath{'}}=0)$ state of CaF to be $\ensuremath{\tau}=19.2\ifmmode\pm\else\textpm\fi{}0.7\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$, and the Franck-Condon factor for the transition to the $X(v=0)$ state to be $Z={0.987}_{\ensuremath{-}0.019}^{+0.013}$. In addition, our analysis provides a measure of the hyperfine interval in the lowest-lying state of $A({v}^{\ensuremath{'}}=0)$, ${\ensuremath{\Delta}}_{e}=4.8\ifmmode\pm\else\textpm\fi{}1.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$.
Experimental results and analysis from the 11 T Nb3Sn DS dipole

FNAL and CERN are developing a 5.5-m-long twin-aperture Nb3Sn dipole suitable for installation in the LHC. A 2-m-long single-aperture demonstrator dipole with 60 mm bore, a nominal field of 11 T at the LHC nominal current of 11.85 kA and 20% margin has been developed and tested. This paper presents the results of quench protection analysis and protection heater study for the Nb3Sn demonstrator dipole. Extrapolations of the results for long magnet and operation in LHC are also presented.
SPECTROSCOPY OF BRIGHT QUEST RR LYRAE STARS: VELOCITY SUBSTRUCTURES TOWARD VIRGO

Using a sample of 43 bright (V < 16.1, distance <13 kpc) RR Lyrae stars (RRLS) from the QUasar Equatorial Survey with spectroscopic radial velocities and metallicities, we find that several separate halo substructures contribute to the Virgo overdensity (VOD). While there is little evidence of a halo substructure in the spatial distribution of these stars, their distribution in radial velocity reveals two moving groups. These results are reinforced when the sample is combined with a sample of blue horizontal branch stars that were identified in the Sloan Digital Sky Survey, and the combined sample provides evidence for one additional moving group. These groups correspond to peaks in the radial velocity distribution of a sample of F-type main-sequence stars that was recently observed in the same direction by the Sloan Extension for Galactic Understanding and Exploration (SEGUE), although in one case the RRLS and F star groups may not lie at the same distance. One of the new substructures has a very narrow range in metallicity, which is more consistent with it being the debris from a destroyed globular cluster than from a dwarf galaxy. A small concentration of stars have radial velocities that are similar to the Virgo Stellar Stream that was identified previously in a fainter sample of RRLS. Our results suggest that this feature extends to distances as short as ∼12 kpc, compared to its previous detection at ∼19 kpc. None of the new groups and only one star in the sample have velocities that are consistent with membership in the leading tidal stream from the Sagittarius dwarf spheroidal galaxy, which some authors have suggested is the origin of the VOD.
On the interaction between embedded planets and the corotation region of protoplanetary discs

Disc material in the corotation region librates with respect to low-mass planets on horseshoe trajectories. The exchange of angular momentum associated with this libration gives rise to the non-linear corotation torque (the horseshoe drag). For the first project described herein, we ran a suite of high-resolution 2D hydrodynamic simulations of low-mass (5 Earth mass) planets, at eccentricities 0 ≤ e < 0.3, embedded in both viscous protoplanetary discs with entropy relaxation and inviscid discs without. The attenuation of the corotation torque was obtained from these simulations and found to be well-fitted by an exponential decay with a characteristic ‘e-folding eccentricity’ that scales linearly with disc scale height. These results were tested with different disc scale heights between 0.03 and 0.1 and with a 10 Earth mass planet. In the second project in this thesis we sought to extend on these results by examining the case of an embedded 5 Earth mass planet in three dimensional discs. We found that our scaling relation held in this new case, confirming that it is possible to use 2D simulations with a softening parameter to capture the behaviour of the corotation torque. We investigated the time-averaged horseshoe width as a function of altitude and found that the corotation region extends from the midplane to around three scale heights, changing most near the midplane for eccentric planets. The final project looked at 3D radiative discs, under the influence of stellar irradiation, with more massive embedded planets capable of triggering gap formation. We use the pluto code to simulate a Jupiter mass planet at 5 AU in a protoplanetary disc. We describe our progress in understanding the process of gap formation in a case study of this class of hitherto undescribed disc.
UNDERSTANDING THE UNUSUAL X-RAY EMISSION PROPERTIES OF THE MASSIVE, CLOSE BINARY WR 20a: A HIGH ENERGY WINDOW INTO THE STELLAR WIND INITIATION REGION

The problem of explaining the X-ray emission properties of the massive, close binary WR 20a is discussed. Located near the cluster core of Westerlund 2, WR 20a is composed of two nearly identical Wolf–Rayet stars of 82 and 83 solar masses orbiting with a period of only 3.7 days. Although Chandra observations were taken during the secondary optical eclipse, the X-ray light curve shows no signs of a flux decrement. In fact, WR 20a appears slightly more X-ray luminous and softer during the optical eclipse, opposite to what has been observed in other binary systems. To aid in our interpretation of the data, we compare with the results of hydrodynamical simulations using the adaptive mesh refinement code Mezcal which includes radiative cooling and a radiative acceleration force term. It is shown that the X-ray emission can be successfully explained in models where the wind–wind collision interface in this system occurs while the outflowing material is still being accelerated. Consequently, WR 20a serves as a critical test-case for how radiatively driven stellar winds are initiated and how they interact. Our models not only procure a robust description of current Chandra data, which cover the orbital phases between 0.3 and 0.6, but also provide detailed predictions over the entire orbit.
Dielectric Properties of (Ba1-xCex)TiO3

Ce substitution for the Ba site shifted the Curie point to a lower temperature than typical substitution with elements such as Zr and Sr. The substitution of Ce for the Ba sites up to 2.0 mol% exhibited a typical donor-doped behavior, the material being fine grained and of depressed dielectric constant at the Curie point. The specimens doped with more than 2.0 mol% CeO2 had relatively high dielectric constant at the Curie point. The increase in dielectric constant at the Curie point seems to be correlated with the grain size. Dielectric properties and microstructure development of highly Ce-doped BaTiO3 are discussed in terms of defects in the cation sublattice.
EVIDENCE OF MULTIPLE SLOW ACOUSTIC OSCILLATIONS IN THE STELLAR FLARING LOOPS OF PROXIMA CENTAURI

We present the first observational evidence of multiple slow acoustic oscillations in the post-flaring loops of the corona of Proxima Centauri using XMM-Newton observations. We find the signature of periodic oscillations localized in the decay phase of the flare in its soft (0.3–10.0 keV) X-ray emissions. Using the standard wavelet tool, we find multiple periodicities of 1261 s and 687 s. These bursty oscillations persist for durations of 90 minutes and 50 minutes, respectively, for more than three cycles. The intensity oscillations with a period of 1261 s may be the signature of the fundamental mode of slow magnetoacoustic waves with a phase speed of 119 km s−1 in a loop of length 7.5 × 109 cm, which is initially heated, producing the flare peak temperature of 33 MK and later cooled down in the decay phase and maintained at an average temperature of 7.2 MK. The other period of 687 s may be associated with the first overtone of slow magnetoacoustic oscillations in the flaring loop. The fundamental mode oscillations show dissipation with a damping time of 47 minutes. The period ratio P1/P2 is found to be 1.83, indicating that such oscillations are most likely excited in longitudinal density stratified stellar loops. We estimate the density scale height of the stellar loop system as ∼23 Mm, which is smaller than the hydrostatic scale height of the hot loop system, and implies the existence of non-equilibrium conditions.
Quantum Darwinism and non-Markovian dissipative dynamics from quantum phases of the spin-1/2 X X model

F.G. and R.Z. acknowledge funding from MINECO, the EU Commission, and FEDER under Grants No. FIS2014-60343-P (NOMAQ), H2020 FET-Proactive project QuPRoCS, and COST Action MP1209. F.G. acknowledges support from the UIB postdoctoral program. G.L. G. acknowledges funding from Compagnia di San Paolo and UIB visiting researchers program.