Miracle-dz/UniFAR-FTUs huggingface dataset:
Superconducting and Normal State Properties of NiBi3.

The electrical resistivity, heat capacity, superconducting upper critical magnetic field and magnetic susceptibility of NiBi 3 have been measured for the polycrystal and needle crystal. The temperature dependence of the resistivity ρ( T ) above the superconducting transition temperature can be explained by the parallel resistor formula. From ρ( T ), using the sum of two Gruneisen-Bloch functions, we have obtained that the lower main value of the Debye temperature is 70 K and the higher one is 300 K. This is compatible with ω E ≡30.6 K and ω D ≡141 K obtained from the heat capacity using the hybrid Einstein-Debye model. We have compared the angular dependence of the critical magnetic field with that of the effective mass model and found an anisotropic mass ratio m ∥ b / m ⊥ b ≈0.17 for the needle (∥ b -axis) crystal. Almost the same value of 0.14 is also obtained from the analysis of ρ( T ).
The scenario of two-dimensional instabilities of the cylinder wake under electrohydrodynamic forcing: a linear stability analysis

We propose to study the stability properties of an air flow wake forced by a dielectric barrier discharge (DBD) actuator, which is a type of electrohydrodynamic (EHD) actuator. These actuators add momentum to the flow around a cylinder in regions close to the wall and, in our case, are symmetrically disposed near the boundary layer separation point. Since the forcing frequencies, typical of DBD, are much higher than the natural shedding frequency of the flow, we will be considering the forcing actuation as stationary. In the first part, the flow around a circular cylinder modified by EHD actuators will be experimentally studied by means of particle image velocimetry (PIV). In the second part, the EHD actuators have been numerically implemented as a boundary condition on the cylinder surface. Using this boundary condition, the computationally obtained base flow is then compared with the experimental one in order to relate the control parameters from both methodologies. After validating the obtained agreement, we study the Hopf bifurcation that appears once the flow starts the vortex shedding through experimental and computational approaches. For the base flow derived from experimentally obtained snapshots, we monitor the evolution of the velocity amplitude oscillations. As to the computationally obtained base flow, its stability is analyzed by solving a global eigenvalue problem obtained from the linearized Navier–Stokes equations. Finally, the critical parameters obtained from both approaches are compared.
A free lunch while designing experiments to estimate azimuthal anisotropy

Summary The No Free Lunch (NFL) theorems state that no single optimization algorithm is ideally suited for all objective functions and, conversely, that no single objective function is ideally suited for all optimization algorithms. We examine the influence of the NFL theorems on a statistical experimental design (SED) application by exploring several design objective functions and several optimization algorithms for designing optimal azimuthal surveys to constrain a model of azimuthal anisotropy. Surprisingly, it is shown that the quality of optimally designed surveys is generally independent of the criterion-algorithm pairing (though it does depend on the optimization algorithms themselves). We demonstrate the principle of diminishing returns in SED, namely that the value of optimizing designs decreases geometrically with survey size. This implies that SED is most effective for the design of compact, information-dense surveys.
Climatology of Environmental Parameters for Mesoscale Convections in Japan

Climatological monthly statistics of parameters that are widely used to characterize the environment for mesoscale convective systems in Japan is studied by using twice-daily (09 and 21 JST: Japan Standard Time) routine rawinsonde data from 18 stations of the Japan Meteorological Agency for the period between 1990 and 1999. The environmental parameters examined include CAPE (Convective Available Potential Energy), CIN (Convective Inhibition), precipitable water, SSI (Showalter Stability Index), and bulk Richardson number. The monthly medians of these parameters have the following characteristics: 1) Large values of CAPE generally occur in summer. Maximum of median CAPE is larger in the southwest than in the northeast of the Japan islands, and the month of the largest CAPE comes earlier in the southwest than it does in the northeast. At a majority of the stations, the medians of CAPE start to increase rapidly from June and remain large until September. 2) Minimum of SSI is generally found during the summer. SSI tends to be smaller for larger CAPE. The frequency that SSI becomes less than or equal to -2 K at 21 JST is significantly higher than that at 09 JST at all stations. In terms of the frequency that SSI becomes less than or equal to -2 K or 0 K, Tateno at 21 JST in August is found to be most unstable among the stations examined. 3) Most of the stations have large CIN in winter and small CIN in summer (July and August), indicating that convection may be triggered by a weaker forcing in summer. 4) Precipitable water shows a smooth seasonal variation with one peak during summer. Precipitable water at night (21 JST) is slightly higher than that at morning (09 JST) at most of the stations all the year round. 5) The largest Bulk Richardson number occurs during summer when CAPE is larger and vertical wind shear is smaller.
Atlas of two-dimensional irreversible conservative Lagrangian mechanical systems with a second quadratic integral

This paper aims at the most comprehensive and systematic construction and tabulation of mechanical systems that admit a second invariant, quadratic in velocities, other than the Hamiltonian. The configuration space is in general a two-dimensional Riemannian or pseudo-Riemannian manifold and the determination of its geometry is a part of the process of solution. Forces acting on the system include a part derived from a scalar potential and a part derived from a vector potential, associated with terms linear in velocities in the Lagrangian function of the system. The last caused time irreversibility of the system. We constructed 41 multiparameter integrable systems of the type described in the title, mostly on Riemannian manifolds. They are mostly new and cover all previously known systems as special cases, corresponding to special values of the parameters. Those include all known cases of motion of a particle in the plane and all known cases in the dynamics of rigid body. In the last field we introduce a n.
Is Parsimony Always Desirable? Identifying the Correct Model for a Longitudinal Panel Data Set

Abstract Marsh and Hau (1996) based the assertion that parsimony is not always desirable when assessing model fit on a particular counterexample drawn from Marsh's previous research. This counterexample is neither general nor valid enough to support such a thesis. More specifically, the counterexample signals an oversight of extant, stochastic models justifying correlated uniquenesses, namely, moving-average and autoregressive moving-average models. Such models provide theoretically plausible motives for a priori specification of error correlations. In fact, when uniquenesses are correlated, stochastic models other than the conventional simplex and quasi-simplex models must be tested before positive identification of the process is possible (Sivo, 1997). In short, exchanging the mechanistic penalties for model complexity for the mechanistic specification of untenable measurement-error covariances offers no solution. Parsimony has not been dismissed based on the argument Marsh and Hau presented concerning .
Detection of the Methyl Radical on Neptune

We report the first detection of the methyl radical (CH3) in the upper atmosphere of Neptune. Observations with the Short-Wavelength Spectrometer of the Infrared Space Observatory (ISO) satellite at a resolving power of 2200 revealed several emission features from the ν2 Q-branch of CH3 around 16.50 μm. The column density of methyl radicals above the 0.2 mbar level is 1.6+1.2−0.9 × 1013 molecules cm-2. Results are compared with predictions of photochemical models. The CH3 abundance is mostly sensitive to the eddy mixing profile and to the poorly known methyl recombination rate at low pressure. Using Slagle et al.'s expression for this rate, the present observations imply an eddy mixing coefficient at the methane homopause in the range of 2-9 × 106 cm2 s-1. Recombination rates higher than used in current photochemical models would lead to larger eddy mixing coefficients.
Global Existence and Gradient Estimates for the Quasilinear Parabolic Equations of m-Laplacian Type with a Nonlinear Convection Term

Abstract In this paper, we derive precise estimates for ∇ u ( t ) including smoothing effects near t =0 and decay as t →∞ as well as global existence of the solutions u ( t ) to the initial-boundary value problem in a bounded domain in R n for the quasilinear parabolic equation of the m Laplacian type with a nonlinear convection term b ( u ) ∇ u . For the initial data u 0 we only assume u 0 ∈ L q ( Ω ), 1⩽ q
Water waves generated by instantaneous disturbances at the bed of a sloping beach

The two-dimensional problem of the generation of water waves due to instantaneous disturbances prescribed at the bed of a beach sloping at an arbitrary angle is studied here. It is formulated in terms of an initial-boundary-value problem for the velocity potential describing the motion in the fluid region assuming the linear theory. Using the Laplace transform in time and the Mellin transform in distance, the problem is reduced to solving a difference equation whose method of solution is of considerable importance in the literature. The form of the free surface is obtained in terms of a multiple infinite integral that is evaluated by the method of steepest-descent. For some prescribed forms of the disturbance at the bed of the beach, the free surface is depicted in a number of figures for different beach angles. It is observed that as the beach angle decreases, the maximum wave height increases, which is plausible.
Large-time behaviour of solutions to non-linear wave equations: higher-order asymptotics

The Cauchy problems for the Korteweg–de Vries–Burgers equation and the Benjamin–Bona– Mahony–Burgers equation are studied. Using subtle estimates of solutions to the linearized equations, the higher-order terms of the asymptotic expansion as of solutions are derived. Copyright © 1999 John Wiley & Sons, Ltd.
Model reduction via balanced realizations: an extension and frequency weighting techniques

Two model-reduction methods for discrete systems related to balanced realizations are described. The first is a technique which utilizes the least controllable and observable subsystem in deriving a balanced discrete reduced-order model. For this technique as L/sup infinity / norm bound on the reduction error is given. The second method is a frequency-weighting technique for discrete- and continuous-time systems where the input-normal or output-normal realizations are modified to include a simple frequency weighting. For this technique, L/sup infinity / norm bounds on the weighted reduction errors are obtained. >
Beam array scattering by a right-angled impedance wedge

The dramatic increase in the use of cellular mobile communications requires an understanding of the signal propagation mechanism. A uniform asymptotic solution for high frequency beam scattering has been described previously (Cheung et al.). The calculation here is extended to an array of complex sources to simulate an aperture distribution tilted away from or directly incident on the edge of an impedance right angle wedge. The solution is uniform across incident and reflection shadow boundaries. The surface wave field contribution is apparent for H-polarization with the surface impedance chosen. The numerical results show interesting polarization dependent differences in the scattering patterns for local beam arrays with their beam axes directed away from the edge of the wedge. Inductive surface reactances characteristic of urban building surfaces show evidence of surface waves for H-polarization but, as expected, not for E-polarization.
Modulated Langmuir waves: Observations from Freja and SCIFER

Modulated Langmuir waves were commonly observed using the HF waveform-capture instruments on the Freja satellite and SCIFER sounding rocket in the terrestrial auroral zone. The modulation frequency of the Langmuir waves during several hundred events was estimated, and found to extend routinely to several tens of kilohertz. Using the linear dispersion relation for oblique Langmuir waves in the ƒpe < ƒce domain, these modulation band widths were found to correspond to interactions between waves at significantly larger angles to each other, and to B0, than typically treated in theoretical analyses of Langmuir wave modulations. A model of the modulation based on scattering via electrostatic whistler/lower hybrid waves is proposed as a viable explanation of the broad modulation bandwidth.
Residual homogenization for seismic forward and inverse problems in layered media

An elastic wavefield propagating in an inhomogeneous elastic medium is only sensitive in an effective way to inhomogeneities much smaller than its minimum wavelength. The corresponding effective medium, or homogenized medium, can be computed thanks to the non-periodic homogenization technique. In the seismic imaging context, limiting ourselves to layered media , we numerically show that a tomographic elastic model which results of the inversion of limited frequency band seismic data is an homogenized model. Moreover, we show that this homogenized model is the same as the model that can be computed with the non-periodic homogenization technique. We first introduce the notion of residual homogenization, which is computing the effective properties of the difference between a reference model and a 'real' model. This is necessary because most imaging technique parametrizations use a reference model that often contains small scales, such as elastic discontinuities. We then use a full-waveform inversion method to numerically show that the result of the inversion is indeed the homogenized residual model. The full-waveform inversion method used here has been specifically developed for that purpose. It is based on the iterative Gauss–Newton least-square non-linear optimization technique, using full normal mode coupling to compute the partial Hessian and gradient. The parametrization has been designed according to the residual ho-mogenized parameters allowing to build a real multiscale inversion with progressive frequency band enrichment along the Gauss–Newton iterations.
Separation in cointegrated systems and persistent-transitory decompositions

The notion of separation in cointegrated systems helps identifying possible sub-system structures that may reduce the complexity of larger systems by yielding a more parsimonious representation of the time series. In this paper the authors demonstrate that although the subsystem cointegration analysis in such systems can be conducted in case of both completely and partially separated systems, the dual approach, i.e. calculation of the common stochastic trends, may turn out to yield properties of the trends that differ depending upon the type of separation under consideration. In particular, they demonstrate how persistent-transitory (P-T) decompositions and long- and short-memory factorizations of a multivariate time series will interact across systems when considering the presence (or absence) of different types of separation. Generalizations to non-linear error correction models are briefly discussed. Copyright 1997 by Blackwell Publishing Ltd
Interlayer bonding energy of layered minerals: Implication for the relationship with friction coefficient

The frictional strength of layered minerals is an important component of fault slip physics. A low‐friction coefficient of these minerals has been attributed to the interlayer bonding energy (ILBE) of their weak interlayer bonding. The ILBE used for discussing the friction coefficient is based on a simple electrostatic calculation; however, the values should be revisited by precise calculations based on quantum mechanics. In this study, the ILBEs of layered minerals were calculated by using the density functional theory (DFT) method with van der Waals correction. The ILBEs calculated by the simple electrostatic method for hydrogen‐bonding minerals such as kaolinite, lizardite, gibbsite, and brucite strongly overestimated the reliable energies calculated by the DFT method. This result should be ascribed to the inaccurate approximation of the point charges at the basal plane. A linear relationship between the experimentally measured friction coefficients of layered minerals and the ILBEs determined by the simple method was not confirmed by using the reliable ILBEs calculated by our DFT method. The results, however, do not remove the possibility of a relationship between interlayer bonding energy and the friction coefficient because the latter, used for comparing the former, was obtained through experiments conducted under various conditions.
Discovery of a Tidal Extension of the Sagittarius Dwarf Spheroidal Galaxy

We report the discovery of stars associated with the Sagittarius dwarf spheroidal galaxy (Sgr) located nearly 10° from the center of the main body of the galaxy, far beyond the outer boundary defined by the star counts of Ibata and coworkers. The newly discovered stars in Sgr include three RR Lyrae stars found serendipitously behind the Galactic globular cluster M55, red horizontal branch stars, and main-sequence stars identified both in the M55 field and in another field located away from this cluster but still about 10° from Sgr. The photometric properties of all of these stars are perfectly consistent with the previously determined distance, metallicity, and age of the Sgr galaxy. Our results indicate that Sgr is much larger than previously believed and that the stellar distribution in the outer parts of the galaxy is probably quite clumpy. We discuss the implications of our findings on the total luminosity and mass of Sgr and on the characteristics of its most recent past perigalacticon passages.
The nonlinear Rashba effect in Hg0.77Cd0.23Te inversion layers probed by weak antilocalization analysis

The Rashba spin-orbit interaction of the two-dimensional electron gas with high mobility in the inversion layer of p-type Hg0.77Cd0. 23Te is investigated by magnetotransport measurements. Both the Rashba spin splitting and Rashba coefficient are extracted by analysis of the weak anti-localization effect using the Golub model. It is found that both the splitting and coefficient increase with increasing electron density (∼3.0–6.0 × 1015 m−2), i.e., with the gate voltage. A self-consistent Schrodinger-Poisson calculation is performed and suggests that the nonlinear Rashba effect caused by the weakening of interband coupling, especially at high electron density, dominates this system.
Non-contact vibration measurement based on an extrinsic Fabry–Perot interferometer implemented using arrays of single-mode fibres

This paper presents a novel non-contact vibration-monitoring technique based on transient measurements from a Fabry–Perot interferometric displacement sensor implemented using single-mode fibre. Two different extrinsic sensor configurations are demonstrated using one-fibre and two-fibre arrays of 4/125 µm single-mode fibre butted with a gradient-index lens. The design concept, mathematical modelling and results are demonstrated. The sensor configurations exploit fringe discrimination over multiple orders. A working range up to 14 µm is demonstrated for the measurement of vibration amplitude at 1 kHz excitation using the one-fibre configuration. Similar tests using the two-fibre configuration indicated a displacement measurement up to 65 µm and vibration measurement up to 7 µm at 2.5 kHz. The two-fibre configuration is also assessed in conjunction with an absolute scheme for the measurement of vibration using dual-wavelength signal processing. In this scheme, two wavelength signals are captured from the sensing interferometer to provide unambiguous measurement of vibration direction.
Direct numerical simulations of turbulent thermal boundary layers subjected to adverse streamwise pressure gradients

An innovative method for prescribing turbulent thermal inflow information in spatially developing boundary layers under streamwise pressure gradients is introduced for attached flows. The approach is tested and validated in a suite of Direct Numerical Simulations (DNS) of thermal boundary layers for zero (ZPG) and adverse (APG) pressure gradients with momentum thickness Reynolds numbers (Reθ) up to 3000. The turbulent thermal data are generated based on the dynamic multi-scale approach proposed by Araya et al. [“A dynamic multi-scale approach for turbulent inflow boundary conditions in spatially evolving flows,” J. Fluid Mech. 670, 581–605 (2011)], which is extended to include thermal field simulations in the present article. The approach is based on the original rescaling-recycling method developed by Lund, Wu, and Squires [“Generation of turbulent inflow data for spatially developing boundary layer simulations,” J. Comput. Phys. 140, 233–258 (1998)] for ZPG flows. Isothermal walls are considered for the.
A morphological survey of bar, lens, and ring components in galaxies Secular evolution in galaxy structure

A morphological survey of barred galaxies is made to investigate the frequency of occurrence, nature, and size distributions of bars, lenses, inner and outer rings, and global spiral structure. The 121 brightest available barred galaxies are examined on Sky Survey copy plates, and on deeper and larger-scale plates, with the following main results.1. Lenses and inner rings are components of major importance in barred galaxies, occurring, respectively, in 54% of SBO--SBa, and 76% of SBab--SBc galaxies. Few early-type galaxies have rings; almost no late-type ones have lenses.2. There is an intimate connection between bars and lenses: in 17 of 20 galaxies with both components, the bar exactly fills the lens in one dimension.3. We suggest that lenses originate as bars, through an unknown process which makes some bars evolve away to a nearly axisymmetric state. Several properties of the proposed process are deduced. We emphasize the possible importance of internal processes of secular evolution in galaxy structure.4. Several galaxies, notably NGC 3945, seem to have strongly triaxial bulge components.5. Inner rings are round. Lenses tend to be slightly triaxial, flattened ellipsoids, with a preferred equatorial axis ratio of approx.0. 9 +- 0.05. Most outer rings are prolate, the shortest dimension beingmore » the one filled by the bar.6. The sizes of bars, rings, and lenses are well correlated with the absolute magnitude of the galaxy, such that the mean surface brightness is constant for each morphological type. The form of the correlation M/sub B/+5 log D= constant is such that these diameters cannot be used as distance indicators. We show that the galaxy mass determines the bar size uniquely.7. Spiral structure in SB galaxies is distorted to resemble inner and outer rings, showing that the arms feel the potential of the bar. Also, of 61 survey galaxies with spiral structure, 55 have global patterns usually interpreted as density waves. « less