Miracle-dz/UniFAR-FTUs huggingface dataset:
Aerodynamic Impact of Vortex Generators on a Relaxed-Compression Low-Boom Inlet

The application of subsonic and supersonic vortex generators for flow control in an external compression, axisymmetric low-boom concept inlet was investigated experimentally and computationally. The low-boom inlet design is conceptually based on a previous scale model tested in the NASA 1×1 ft supersonic wind tunnel. It features a zero-angle cowl and relaxed isentropic compression centerbody spike, resulting in defocused oblique shocks and a weak terminating normal shock. A design of experiments computational methodology was used to select device size and location to determine the optimal choice of device geometry and placement, with the objective of reducing radial flow distortion for on-design conditions. The resulting test matrix of vortex generator geometry and placement was specified for model inlet testing conducted at the 8×6 ft supersonic wind tunnel at NASA Glenn Research Center in the Fall of 2010. Comparisons of Reynolds-averaged Navier–Stokes predictions with experimental data were subsequen.
An anticorrelation between barycentre offsets and velocity dispersion for highest overdensity subhaloes in cosmological simulations

In this paper, we use two hydrodynamic simulations to study the barycentre offsets $r_{{\rm off}}$ between the entire halo and the gas or dark matter subhalo with largest overdensity. We restrict our analysis to those halos with large rescaled offsets, i.e. $r_{{\rm off}}/r_{200}\gtrsim 0.05$. The halos which are less massive and at higher redshifts are more likely to have larger $r_{{\rm off}}/r_{200}$. The 3D velocity dispersion of the subhalos with largest overdensity is found to have a similar mass and redshift dependence as $r_{{\rm off}}/r_{200}$. We also find that the gas subhalos with maximum overdensity and larger gas velocity dispersion $\sigma_{v}^{\rm ICM,sub}/\sigma_{200}$ tend to have smaller barycentre offsets $r_{{\rm off}}/r_{200}$. Similar result is found for the highest overdensity dark matter subhalos but with less significance. This anti-correlation is more significant for the snapshot $z=0$ than $z=0.2$ and $0.5$. The underlying physical mechanism for this anti-correlation remains to be explored.
The Mode of Vibration of a Clarinet Reed

Theoretical explanations of the action of the vibrating clarinet reed have been based upon the assumption of the partial closing of the aperture under the reed. This assumption is not supported by experimental evidence. The motion of the reed was observed stroboscopically, with the tone produced by an artificial embouchure. The actual frequency of the reed has been determined and other details in the mode of vibration observed.
Quantum spiral spin-tensor magnetism

The characterization of quantum magnetism in a large spin ($\ensuremath{\ge}1$) system naturally involves both spin vectors and spin tensors. While certain types of spin-vector (e.g., ferromagnetic, spiral) and spin-tensor (e.g., nematic in frustrated lattices) orders have been investigated separately, the coexistence and correlation between them have not been well explored. Here, we propose a quantum spiral spin-tensor order on a spin-1 Heisenberg chain subject to a spiral spin-tensor Zeeman field, which can be experimentally realized using a Raman-dressed cold atom optical lattice. We develop a method to fully characterize quantum phases of such spiral tensor magnetism with the coexistence of spin-vector and spin-tensor orders as well as their correlations using eight geometric parameters. Our method provides a powerful tool for characterizing spin-1 quantum magnetism and opens an avenue for exploring magnetic orders and spin-tensor electronics and atomtronics in large-spin systems.
On non-commutative G2 structure

Using an algebraic orbifold method, we present non-commutative aspects of G2 structure of seven-dimensional real manifolds. We first develop and solve the non-commutativity parameter constraint equations defining G2 manifold algebras. We show that there are eight possible solutions for this extended structure, one of which corresponds to the commutative case. Then, we obtain a matrix representation solving such algebras using combinatorial arguments. An application to matrix model of M-theory is discussed.
CNO Abundances of BA-Type Supergiants

Massive BA-type supergiants are among the visually brightest stars in galaxies with active star formation. As such they are versatile tools for studies of stellar and galactochemical evolution. Moreover, they can act as distance indicators for the calibration of the cosmological distance scale. In the present work abundance patterns of the light elements helium, carbon, nitrogen and oxygen are investigated in several Galactic BA-type supergiants in the mass range between 8 and 18 M_sun. Based on high-resolution and high-S/N Echelle spectra obtained with FOCES on the Calar Alto 2.2m telescope, model atmosphere analyses are performed using state-of-the-art non-LTE spectrum synthesis. Stellar parameters and chemical abundances are determined with high accuracy. This gives tight observational constraints on the evolutionary status of the stars. Objects evolving from the main sequence to the red supergiant stage and those on a blue loop can be distinguished by their mixing signature (pure rotational vs. first dredge-up). The most sensitive tracer of nuclear processed matter, the N/C ratio, indicates a higher mixing efficiency than predicted by current evolution models of rotating stars with mass-loss.
Catching Attention in Fiber Optics Class

Following a brief review on the history and the current development of fiber optics, the significance of teaching fiber optics for science and non-science major college students is addressed. Several experimental demonstrations designed to aid the teaching and learning process in fiber optics lectures are presented. Sample laboratory projects are also proposed to help the students to understand the physical principles of fiber optics.
Compton Edge probing basic physics at Jefferson Laboratory: light speed isotropy and Lorentz invariance

We propose to study of the light speed isotropy and Lorentz invariance at Jefferson Laboratory by means of the measurements of the Compton Edge using of the Hall A/C existing experimental setup. Methodologically the same experiment has already been successfully elaborated at GRAAL experiment at the European Synchrotron Radiation Facility in Grenoble with 6 GeV electron beam. This Proposal states two goals expected to be reached at Jefferson Laboratory, both on Lorentz invariance: (a) the one-way light speed isotropy testing accuracy, following from conservative evaluations at numerical simulations, to about an order of magnitude better than was GRAAL's; (b) the dependence of the light speed on the velocity of the apparatus (Kennedy-Thorndike measurement) will be traced to an accuracy about 3 orders of magnitudes better than the available limits.
Peering Through the Dust. II. XMM-Newton Observations of Two Additional FIRST-2MASS Red Quasars

We obtained XMM-Newton observations of two highly luminous dust-reddened quasars, F2M1113+1244 and F2M1656+3821, that appear to be in the early, transitional phase predicted by merger-driven models of quasar/galaxy co-evolution. These sources have been well studied at optical through mid-infrared wavelengths and are growing relatively rapidly, with Eddington ratios . Their black hole masses are relatively small compared to their host galaxies, placing them below the relation. We find that for both sources, an absorbed power-law model with 1%–3% of the intrinsic continuum scattered or leaked back into the line of sight best fits their X-ray spectra. We measure the absorbing column density (NH) and constrain the dust-to-gas ratios in these systems, finding that they lie well below the Galactic value. This, combined with the presence of broad emission lines in their optical and near-infrared spectra, suggests that the dust absorption occurs far from the nucleus and in the host galaxy, while the X-rays are mostly absorbed in the nuclear, dust-free region within the sublimation radius. We also compare the quasars’ absorption-corrected, rest-frame X-ray luminosities (2–10 keV) to their rest-frame infrared luminosities (6 μm) and find that red quasars, similar to other populations of luminous obscured quasars, are either underluminous in X-rays or overluminous in the infrared.
Fibre Bragg grating sensors in polymer optical fibres

This review paper summarizes the current state of research into polymer optical fibre grating sensors. The properties of polymers are explored to identify situations where polymers offer potential advantages over more conventional silica fibre sensing technology. Photosensitivity is discussed and the sensitivities of polymer fibre gratings to strain, temperature and water are described. Finally, applications are reported which utilize the unique properties of polymer fibres.
Competing phases and topological excitations of spin-1 pyrochlore antiferromagnets

Most works on pyrochlore magnets deal with the interacting spin-1/2 local moments. We here study the spin-one local moments on the pyrochlore lattice, and propose a generic interacting spin model on a pyrochlore lattice. Our spin model includes the antiferromagnetic Heisenberg interaction, the Dzyaloshinskii-Moriya interaction and the single-ion spin anisotropy. We develop a flavor wave theory and combine with a mean-field approach to study the global phase diagram of this model and establish the relation between different phases in the phase diagram. We find the regime of the quantum paramagnetic phase where a degenerate line of the magnetic excitations emerges in the momentum space. We further predict the critical properties of the transition out of the quantum paramagnet to the proximate orders. The presence of quantum order by disorder in the parts of the ordered phases is then suggested. We point out the existence of degenerate and topological excitations in various phases. We discuss the relevance with fluoride pyrochlore material NaCaNi$_2$F$_7$ and explain the role of the spin-orbit coupling and the magnetic structures of the Ru-based pyrochlore A$_2$Ru$_2$O$_7$ and the Mo-based pyrochlore A$_2$Mo$_2$O$_7$.
Broad-lined Supernova 2016coi with a Helium Envelope

We present the early-phase spectra and the light curves of the broad-lined (BL) supernova (SN) 2016coi from t = 7 to 67 days after the estimated explosion date. This SN was initially reported as a BL Type SN Ic (SN Ic-BL). However, we found that spectra up to t = 12 days exhibited the He i λ5876, λ6678, and λ7065 absorption lines. We show that the smoothed and blueshifted spectra of normal SNe Ib are remarkably similar to the observed spectrum of SN 2016coi. The line velocities of SN 2016coi were similar to those of SNe Ic-BL and significantly faster than those of SNe Ib. Analyses of the line velocity and light curve suggest that the kinetic energy and the total ejecta mass of SN 2016coi are similar to those of SNe Ic-BL. Together with BL SNe 2009bb and 2012ap, for which the detection of He i was also reported, these SNe could be transitional objects between SNe Ic-BL and SNe Ib, and be classified as BL Type “Ib” SNe (SNe “Ib”-BL). Our work demonstrates the diversity of the outermost layer in BL SNe, which should be related to the variety of the evolutionary paths.
Shark: introducing an open source, free, and flexible semi-analytic model of galaxy formation

We present a new, open source, free semi-analytic model (SAM) of galaxy formation, Shark, designed to be highly flexible and modular, allowing easy exploration of different physical processes and ways of modelling them. We introduce the philosophy behind Shark and provide an overview of the physical processes included in the model. Shark is written in C++11 and has been parallelized with OpenMP. In the released version (v1.1), we implement several different models for gas cooling, active galactic nuclei, stellar and photo-ionisation feedback, and star formation (SF). We demonstrate the basic performance of Shark using the Planck15 cosmology SURFS simulations, by comparing against a large set of observations, including: the stellar mass function (SMF) and stellar-halo mass relation at z=0-4; the cosmic evolution of the star formation rate density (SFRD), stellar mass, atomic and molecular hydrogen; local gas scaling relations; and structural galaxy properties, finding excellent agreement. Significant improvements over previous SAMs are seen in the mass-size relation for disks/bulges, the gas-stellar mass and stellar mass-metallicity relations. To illustrate the power of Shark in exploring the systematic effects of the galaxy formation modelling, we quantify how the scatter of the SF main sequence and the gas scaling relations changes with the adopted SF law, and the effect of the starbursts H$_2$ depletion timescale on the SFRD and $\Omega_{\rm H_2}$. We compare Shark with other SAMs and the hydrodynamical simulation EAGLE, and find that SAMs have a much higher halo baryon fractions due to large amounts of intra-halo gas, which in the case of EAGLE is in the intergalactic medium.
Beam shaping algorithm with optimization parameters

In this article, we present a general mode-conversion algorithm allowing to build an optical system composed of an alternation of phase masks and free propagations. The originality of our approach lies in the introduction of free parameters that can be used to perform an optimization regarding some properties of interest. Here, we apply this algorithm to overlap balancing, for the conversion of an important number of modes with limited phase resources. Moreover, we discuss about the convergence and the limitations of such an algorithm, notably concerning the loss of unitarity that tends to occur in a practical implementation.
Super-resolution imaging within reach

Although several optical techniques have been developed to overcome the resolution limit in microscopy, the optical imaging of subwavelength features is still a real challenge (difficulty to build, or risks of phototoxicity). Microsphere-assisted microscopy has recently made super-resolution imaging accessible to scientists. An easy-to-implement optical setup to perform full-field and contactless super-resolution measurements using transparent microspheres is presented. We show that this rather simple imaging system (in comparison with the usual optical nanoscopes) makes it possible to achieve a lateral resolution of 200 nm in air and, thus, to visualize nanostructured media and biological elements.
Emergence of theGaiaphase space spirals from bending waves

We discuss the physical mechanism by which pure vertical bending waves in a stellar disc evolve to form phase space spirals similar to those discovered by Antoja et al. ( arXiv:1804.10196) in Gaia Data Release 2. These spirals were found by projecting Solar Neighbourhood stars onto the $z-v_z$ plane. Faint spirals appear in the number density of stars projected onto the $z-v_z$ plane, which can be explained by a simple model for phase wrapping. More prominent spirals are seen when bins across the $z-v_z$ plane are coloured by median $v_R$ or $v_\phi$. We use both toy model and fully self-consistent simulations to show that the spirals develop naturally from vertical bending oscillations of a stellar disc. The underlying physics follows from the observation that the vertical energy of a star (essentially, its "radius" in the $z-v_z$ plane) correlates with its angular momentum or, alternatively, guiding radius. Moreover, at fixed physical radius, the guiding radius determines the azimuthal velocity. Together, these properties imply the link between in-plane and vertical motion that lead directly to the Gaia spirals. We show that the cubic $R-z$ coupling term in the effective potential is crucial for understanding the morphology of the spirals. This suggests that phase space spirals might be a powerful probe of the Galactic potential. In addition, we argue that self-gravity is necessary to properly model the evolution of the bending waves and their attendant phase space spirals.
Conformational switching of chiral colloidal rafts regulates raft–raft attractions and repulsions

Significance We describe hierarchical assemblages of colloidal rods that mimic some of the complexity and reconfigurability of biological structures. We show that chiral rod-like inclusions dissolved in an achiral colloidal membrane assemble into rafts, which are adaptable finite-sized liquid droplets that exhibit 2 distinct chiral states of opposite handedness. Interconverting between these 2 states switches the membrane-mediated raft interactions between long-ranged repulsions and attractions. Rafts with switchable interactions assemble into analogs of electrostatic complexation observed in charged particulate matter. Our results demonstrate a robust pathway for self-assembly of reconfigurable colloidal superstructures that does not depend on tuning the shape and interactions of the elemental units, but rather on the complexity of the emergent membrane-mediated interactions. Membrane-mediated particle interactions depend both on the properties of the particles themselves and the membrane environment in which they are suspended. Experiments have shown that chiral rod-like inclusions dissolved in a colloidal membrane of opposite handedness assemble into colloidal rafts, which are finite-sized reconfigurable droplets consisting of a large but precisely defined number of rods. We systematically tune the chirality of the background membrane and find that, in the achiral limit, colloidal rafts acquire complex structural properties and interactions. In particular, rafts can switch between 2 chiral states of opposite handedness, which alters the nature of the membrane-mediated raft–raft interactions. Rafts with the same chirality have long-ranged repulsions, while those with opposite chirality acquire attractions with a well-defined minimum. Both attractive and repulsive interactions are qualitatively explained by a continuum model that accounts for the coupling between the membrane thickness and the local tilt of the constituent rods. These switchable interactions enable assembly of colloidal rafts into intricate higher-order architectures, including stable tetrameric clusters and “ionic crystallites” of counter-twisting domains organized on a binary square lattice. Furthermore, the properties of individual rafts, such as their sizes, are controlled by their complexation with other rafts. The emergence of these complex behaviors can be rationalized purely in terms of generic couplings between compositional and orientational order of fluids of rod-like elements. Thus, the uncovered principles might have relevance for conventional lipid bilayers, in which the assembly of higher-order structures is also mediated by complex membrane-mediated interactions.
Gauging of equations method. II. Electromagnetic currents of three identical particles

The gauging of equations method, introduced in the preceding paper, is applied to the four-dimensional integral equations describing the strong interactions of three identical relativistic particles. In this way we obtain gauge-invariant expressions for all possible electromagnetic transition currents of the identical three-particle system. In the three-nucleon system with no isospin violation, for example, our expressions describe the electromagnetic form factors of ${}^{3}\mathrm{H},$ $p\stackrel{\ensuremath{\rightarrow}}{d}\mathrm{pd}\ensuremath{\gamma},$ ${\ensuremath{\gamma}}^{3}\mathrm{He}\ensuremath{\rightarrow}pd,$ ${\ensuremath{\gamma}}^{3}\mathrm{He}\ensuremath{\rightarrow}ppn,$ etc. A feature of our approach is that gauge invariance is achieved through the coupling of the photon to all possible places in the (nonperturbative) strong interaction model. Moreover, once the proper identical particle symmetry is incorporated into the integral equations describing the strong interactions, the gauging procedure automatically provides electromagnetic transition currents with the proper symmetry. In this way the gauging of equations method results in a unified description of strong and electromagnetic interaction of strongly interacting systems.
Bulk Mass-Flux Perturbation Formulation for a Unified Approach of Deep Convection at High Resolution

AbstractParameterizing deep convection at model resolutions of a few kilometers or less requires diverging from several simplifying assumptions valid at coarser resolutions. The separation or complementarity between the deep-convection scheme and the model cloud scheme must be addressed properly to prevent a double counting of some phenomena, account for evolution in time, and keep consistent results while approaching resolutions where deep convection can be treated explicitly (without parameterization). In this paper, the author formulates and tests a perturbation approach of the bulk mass-flux representation of deep convective updrafts and downdrafts. The subgrid deep-convection scheme represents only the effect of the unresolved part of the real updrafts, complementing an explicit part associated with the mean gridbox vertical velocity. Special attention is paid to the ordering and interactions of the moist parameterizations, the formulation of the closure and of the triggering, and the accounting of t.
Comparison of kernel-based methods for spectral signature detection and classification of hyperspectral images

The aim of this paper is to assess and compare the performance of two kernel-based classification methods based on two different approaches. On one hand the Support Vector Machine (SVM), which in the last years has shown excellent results for hard classification of hyperspectral data; on the other hand a detection method called Kernel Orthogonal Subspace Projection KOSP, proposed in a recent paper.1 To this aim, the widely used "Indian Pine" Aviris dataset is adopted, and a common "test protocol" has been considered: both methods have been tested adopting the one-vs-rest strategy, i.e. by performing the detection of each spectral signature (representing one of the N classes) and by considering the spectral signatures of the remaining N - 1 classes as background. The same dimensionality of the training set is also considered in both approaches.
Energy Stable Interior Penalty Discontinuous Galerkin Finite Element Method for Cahn–Hilliard Equation

Abstract An energy stable conservative method is developed for the Cahn–Hilliard (CH) equation with the degenerate mobility. The CH equation is discretized in space with the mass conserving symmetric interior penalty discontinuous Galerkin (SIPG) method. The resulting semi-discrete nonlinear system of ordinary differential equations are solved in time by the unconditionally energy stable average vector field (AVF) method. We prove that the AVF method preserves the energy decreasing property of the fully discretized CH equation. Numerical results for the quartic double-well and the logarithmic potential functions with constant and degenerate mobility confirm the theoretical convergence rates, accuracy and the performance of the proposed approach.
Disorder in Diluted Spin Systems

The influence of substitutional disorder on the magnetic properties of diluted Heisenberg spin systems is studied with regard to the magnetic stability of ferromagnetic diluted semiconductors (DMS). The equation of motion for the magnon Green's function within Tyablikov approximation is solved numerically for finite systems. The resulting spectral density is then used to estimate the magnetization and Curie temperature of an infinite system. This method is suitable for any form of a ferromagnetic exchange interaction. Besides different lattices and spin magnitude $S$, exchange interactions of different range are examined. The results show that, for short-range interaction, no magnetic order exists below the critical percolation concentration, whereas a linear dependence of the Curie temperature on the concentration of spins is found for ferromagnetic long-range interaction.