Miracle-dz/UniFAR-FTUs huggingface dataset:
Effective room-temperature luminescence in annealed chromium-doped silicate optical fibers

The influence of annealing at 1000 °C on the absorption and luminescence spectra of chromium in aluminosilicate and gallium silicate fibers at temperatures of 77 and 300 K is investigated. The spectra of initially weak luminescence with a maximum at 1100 nm and a quantum yield of approximately 10-5 at 300 K shift to the 790–880-nm range in annealed fibers. After annealing the quantum yield increases by as much as 10%. The luminescence lifetime is found to be approximately 20 μs. The luminescence changes are explained by a rearrangement of the nearest environment and recharge of chromium ions (Cr4+ to Cr3+). The results obtained hold promise for the creation of tunable and ultrashort pulse fiber lasers.
The Regime Dependence of Degree Day Forecast Technique, Skill, and Value

Abstract An investigation into the manner in which forecasters adjust their reliance on particular pieces of forecast information as the large-scale flow pattern evolves into different regimes, and the relationship between those adjustments and forecast skill and value is presented. For the cold season months (December–February) of the period 1 January 1973 through 31 December 1992, a total of three regime types (identified through cluster analysis) comprising 63% of the days were identified. A framework for investigating the weighting of pieces of forecast information, based upon multiple regression techniques, was applied to National Weather Service (NWS) degree day forecasts (constructed from the 12–24-h minimum and 24–36-h maximum temperature forecasts) for this period. It was determined that substantial changes in the usage of Model Output Statistics (MOS) by NWS forecasters have occurred with the advent of the improved numerical model guidance represented by the Limited Fine Mesh (LFM) MOS, and that.
On the distribution of the integrated square of the Ornstein-Unlenbeck process

Using functional integral methods, the Laplace transform of the square of the Ornstein-Uhlenbeck process $X( t )$ integrated over $0\leqq t\leqq T$ is calculated. Via the complex inversion integral, the asymptotic behavior as $T \to \infty $ of the density and distribution functions, as well as these functions conditioned on the event $X( T ) = 0$, are studied. It is found that the approximation by an inverse Gaussian distribution, introduced earlier by Grenander, Pollak, and Slepian, is asymptotically correct (to within a constant factor) in the conditional case, but not in the unconditional case.
Analytical and numerical treatment of a complex model for Hele-Shaw moving boundary value problems with kinetic undercooling regularization

In this paper, a complex variable model for Hele-Shaw moving boundary problems with kinetic undercooling regularization is studied. This model consists of an abstract Cauchy–Kovalevsky problem and of a Riemann–Hilbert–Poincaré problem for holomorphic functions. The local existence of holomorphic solutions is shown. Some numerical results for this model complete the paper.
That BLUP is a Good Thing: The Estimation of Random Effects

In animal breeding, Best Linear Unbiased Prediction, or BLUP, is a technique for estimating genetic merits. In general, it is a method of estimating random effects. It can be used to derive the Kalman filter, the method of Kriging used for ore reserve estimation, credibility theory used to work out insurance premiums, and Hoadley's quality measurement plan used to estimate a quality index. It can be used for removing noise from images and for small-area estimation. This paper presents the theory of BLUP, some examples of its applica- tion and its relevance to the foundations of statistics. Understanding of procedures for estimating random effects should help people to understand some complicated and controversial issues about fixed and random effects models and also help to bridge the apparent gulf between the Bayesian and Classical schools of thought.
Uniform surface‐to‐line integral reduction of physical optics for curved surfaces by Keller‐type equivalent edge currents in MER: Behaviors of fields on reflection shadow boundary

The Modified Edge Representation (MER) is a procedure for defining the equivalent edge currents (EECs) to be used in the surface‐to‐line integral reduction for computing the physical optics radiation integrals in diffraction analysis. The physical optics surface integration is transformed into the line integration of MER‐EECs rigorously for the planar surfaces. It works with the remarkable accuracy even for the curved surface. In contrast to conventional EECs, those in MER are defined without ambiguity not only at the diffraction points but also at arbitrary ones along the periphery. One remarkable advantage is that the MER‐EECs, after integrated along periphery, provide uniform fields across the geometrical shadow boundaries though the EECs in the integrand consist of nonuniform Keller‐type diffraction coefficients. As the starting point of the applicability check of MER for the curved surfaces, this paper investigates the MER diffraction field behaviors on and near the reflection shadow boundary (RSB). First, the stabilities or the robustness of the numerical line integration are interpreted. Second, the dependence of the RSB field errors upon the curvature of the surfaces is investigated. They become smaller in higher frequency and are related with the aberration of the geometrical reflected ray; for the dipole wave illumination, the error is generally smaller and larger for the concave and convex surfaces, respectively. This surface shape dependence of MER errors in diffraction is quite analogous to those in predicting geometrical optics contributions, the latter of which is the complement of the former and was previously reported by the authors.
A SIMPLE CRITERION FOR ESTABLISHING AN UPPER LIMIT TO THE HARMONIC EXCITATION LEVEL OF THE DUFFING OSCILLATOR USING THE VOLTERRA SERIES

Abstract High order frequency response functions, based on the Volterra series, are employed to represent the input-output characteristics of the Duffing oscillator subject to sinusoidal excitation. From these a series representation of a first order frequency response function of the non-linear system is obtained and used to derive a simple criterion which provides an estimate of the magnitude of the input sine-wave above which the predicted response begins to diverge. The criterion results in a small overestimate of the magnitude of the input force excitation at the undamped natural frequency condition. Although the derived criterion strictly applies only to the Duffing oscillator, the procedure can be applied generally and is extended to a two-degree-of-freedom system with a non-linear cubic stiffness producing a similar criterion to that of the single degree-of-freedom system.
Penetrative turbulent convection into a rotating two-layer fluid

Turbulent convection into stratified two-layer fluid systems in the presence of rotation has been investigated in a cylindrical laboratory tank. For a wide range of conditions the vertical stability of the flow depends only on the Richardson number Ri = g′h0/(B0R)2/3 (here, g′ = gδ ρi/ρ0 is the jump in the reduced gravity across the density interface, δ ρi is the jump in density itself, h0 is the depth of the top layer, B0 is the surface buoyancy flux and R is the radius of the source). We have found that for values of Ri greater than a critical value of Ric ≈ 11, the convective flow did not penetrate through the density interface, regardless of the values of the convective Rossby number Ro* = (B0/f3h02)1/2 of the flow (here f is the Coriolis parameter). In this case after the convective layer interacted with the density interface the mixed fluid, of intermediate density, propagated radially along the interface in the form of an intrusion. Later, if Ro* was less than approximately 5, mesoscale vortices with mean diameter D ≈ 8(RoR)2/3 and maximum swirl velocity v ≈ (B0R)1/3 were generated at the edge of this propagating front (here RoR = (B0/f3R2)1/2 is the Rossby number based on R). When Ri was less than 11, the convective flow eventually penetrated through the density interface and into the bottom layer. This occurred through the formation of discrete ‘convective holes’ beneath the source. At large values of Ro*, and at early times, one turbulent plume penetrated into the bottom layer from each hole. Later the initial holes coalesced to create one large lesion beneath the source.
Optical tomography system using switch mode fan beam projection: modeling techniques

This research concentrates on the implementation of 16 pairs of optical sensors in a process tomography system. The working principle is based on the switch and measure principle in electrical capacitance tomography (ECT), but uses fan beam shaped projection from light emitters. The fast settling time of optical sensors and wide coverage of an optical beam forms the interest to be implemented in a tomography system. At the initial stage, modeling has been carried out to predict the output from 16 pairs of optical sensors implemented with the switching principle. The 16 pairs of optical sensors consist of 16 3-mm PIN photodiodes and 16 3-mm LEDs. The idea is applied with the assumption that the emission angle of the source is large enough to illuminate all the receivers and the emission power is uniform along the projection. The linear back projection algorithm is used to predict the result from the modeling. The results for concentration profiles and reconstructed images of the original objects show significant agreement for further research.
Anisotropic dynamics and sub-grid energy transfer in wall-turbulence

Purpose of the present work is the analysis of the generalized Kolmogorov equation applied to the direct numerical simulation data of a turbulent channel flow. The multi-dimensional description of the anisotropic behavior of turbulent energy production, transport, and dissipation is shown to be relevant for the understanding and modeling of the wall-turbulent physics with special care to the phenomenon of reverse energy flux. These results are proven instrumental also for the correct computation of wall-turbulence when a large eddy simulation approach is considered. The capability of a filtered velocity field to correctly reproduce the wall-turbulent dynamics at different ranges of scales and wall-distances as a function of the filter length will be assessed via filtered direct numerical simulation (DNS) and large eddy simulation data. The possibility of new modeling approaches is also highlighted.
SIGNATURE ASYMPTOTIQUE D'UN CHAMP DE VECTEURS EN DIMENSION 3

Consider a volume preserving vector field defined in some compact domain of 3space and tangent to its boundary. A long piece of orbit can be made into a knot by connecting its endpoints by some arc whose length is less than the diameter of the domain. In this paper, we study the behaviour of the signatures of these knots as the lengths of the pieces of orbits go to infinity. We relate this “asymptotic signature”to the “asymptotic Hopf invariant”that has been studied by Arnold.
A broad-band dual-polarized microstrip patch antenna with aperture coupling

In this communication, a dual-polarized aperture-coupled microstrip patch antenna with a broad-bandwidth high-isolation low cross-polarization levels, and low-backward radiation levels is designed and its features are presented. For broad bandwidth and easy integration with active circuits, it uses the aperture-coupled stacked patches. The corner feeding of square microstrip patches is applied and the coupling aperture is the H-shaped aperture. The theoretical analysis is based on the finite-difference time-domain (FDTD) method. A dual-polarized antenna is designed, fabricated, and measured. The measured return loss exhibits an impedance bandwidth of over 24.4% and the isolation is better than 30 dB over the bandwidth. The cross-polarization levels in both E and H planes are better than -23 dB. The front-to-back ratio of the antenna radiation pattern is better than 22 dB. Both theoretical and experimental results for S parameters and radiation patterns are presented and discussed.
On the stability of vertical double-diffusive interfaces. Part 3. Cylindrical interface

This is the final part of a three-part study of the stability of vertically oriented double-diffusive interfaces having an imposed vertical stable temperature gradient. In this study, flow is forced within a fluid of infinite extent by a prescribed excess of compositionally buoyant material within a circular cylindrical interface. Compositional diffusivity is ignored while thermal diffusivity and viscosity are finite. The instability of the interface is determined by quantifying the exponential growth rate of a harmonic deflection of infinitesimal amplitude. Attention is focused on the zonal wavenumber of the fastest growing mode. The interface is found to be unstable for some wavenumber for all values of the Prandtl number and interface radius. The zonal wavenumber of the fastest growing mode increases roughly linearly with interface radius, except for small values of the Prandtl number (<0.065). For small and moderate values of the radius, the preferred mode is either axisymmetric or has zonal wavenumber of 1, representing a helical instability. The growth rate of the fastest-growing mode is largest for interfaces having radii of from 2 to 3 salt-finger lengths.
Erratum: “Stellar Halo Parameters from 4588 Subdwarfs” (ApJ, 583, 765 [2003])

Using a reduced proper motion discriminator, I obtain a sample of 4588 subdwarfs from the Revised NLTT Catalog of Salim & Gould. The ample statistics and low contamination permit much more precise determinations of halo parameters than has previously been possible. The stellar halo is not moving with respect to the Local Standard of Rest (LSR) in either the vertical or radial direction, up to uncertainties of 2 km/s. This indicates that either the LSR is on a circular orbit or the Sun happens to lie very close to an extremum of the LSR's elliptical orbit. Similarly, tentative detections of vertical proper motion of Sgr A* relative to the LSR are either incorrect or they reflect real physical motion of the central black hole relative to the Galactic potential. The correlation coefficients of the halo velocity ellipsoid, which would reflect any possible misalignment between its principal axes and the cardinal directions of the Galaxy, vanish to within 2%. The halo subdwarf luminosity function peaks at M_V ~ 10.5 with a full width half maximum of about 2.5 mag.
Impacts of vortex intensity and outer winds on tropical cyclone size

The present study seeks to understand how the initial vortex intensity and outer winds influence tropical cyclone (TC) size, which is defined as the azimuthally averaged radius of the 10 m 17 m s−1 wind from the TC centre (R17), using a full baroclinic model in a quiescent f‐plane environment. The initial vortex intensity is found to influence the size growth rate in the developing phase of the vortex life cycle. However, when the vortex comes to the mature and/or decaying phase of the vortex life cycle, the initial vortex intensity (ranging between 20 and 40 m s−1 in this study) does not strongly affect TC size. On the other hand, vortex intensification or re‐intensification resulting from inner‐core dynamics is apparently favourable for size growth in most instances. In addition, the lower‐tropospheric outer winds of a vortex (i.e. winds beyond R17; e.g. the environmental flows around the TC) are found to be an important factor governing size change. The outer winds closer to R17 are more effective and can influence the vortex size at an earlier stage, especially if the winds are strong.
Diffusive-dispersive travelling waves and kinetic relations. II A hyperbolic–elliptic model of phase-transition dynamics

We deal here with a mixed (hyperbolic-elliptic) system of two conservation laws modelling phase-transition dynamics in solids undergoing phase transformations. These equations include nonlinear viscosity and capillarity terms. We establish general results concerning the existence, uniqueness and asymptotic properties of the corresponding travelling wave solutions. In particular, we determine their behaviour in the limits of dominant diffusion, dominant dispersion or asymptotically small or large shock strength. As the viscosity and capillarity parameters tend to zero, the travelling waves converge to propagating discontinuities, which are either classical shock waves or supersonic phase boundaries satisfying the Lax and Liu entropy criteria, or else are undercompressive subsonic phase boundaries. The latter are uniquely characterized by the so-called kinetic function, whose properties are investigated in detail here.
Topics in associated J/{psi}+c+c production at modern colliders

In the framework of perturbative QCD and nonrelativistic bound state formalism, we calculate the production of J/{psi} mesons associated with open-charm particles at HERA and Tevatron conditions. We show that the contribution from J/{psi}+c+c channel becomes comparable with that of J/{psi} sole production at high J/{psi} transverse momenta (approximately, at p{sub {psi},T}>10 GeV). We investigate the J/{psi} polarization effects and kinematic correlations between J/{psi} mesons and the accompanying open-charmed mesons. We show that the correlations are sensitive to the initial k{sub t} of the colliding partons, and so, can be considered as an additional test discriminating the collinear parton model and the k{sub t}-factorization approach.
Influence of amylose content on the viscous behavior of low hydrated molten starches

Starches with various amylose contents (0%–70%) were processed on a twin‐screw extruder equipped with a special slit die rheometer. Relationships between thermomechanical treatment and starch macromolecular degradation are defined, and flow curves are discussed in order to determine the role of moisture content, product temperature, and mechanical energy on melt viscosity. The viscous behavior is described by a power‐law expression. Viscosity is more sensitive to moisture content and macromolecular degradation at lower amylose contents. Using multiple regression analysis, expressions for the different starches are proposed to describe the influence on the viscosity of amylopectin, which is the macromolecular component with short chain branching. The main differences observed when decreasing the amylose content are a lower viscosity and less pronounced shear thinning. These effects are interpreted in terms of entanglements.
In situ measurement of size and density of submicron aerosol particles

The density of nanometer sized particles of different materials (Pd, Ag, Co, Carbon, oil droplets and oil burner exhaust) suspended in a carrier gas is determined in situ as function of particle radius via the measurement of particle mobility and inertia using a differential mobility analyzer and a low pressure impactor. From the density and size of agglomerated particles, information on the structure of the agglomerates can be obtained; in particular a fractal‐like dimension can be determined. Whereas the densities of carbon particles and of particles in oil burner exhaust have the expected values, the densities of the metal particles are too low compared to the bulk values. The results for the fractal‐like dimensions of the agglomerates can be explained by assuming a mixture between monomer‐cluster and cluster‐cluster agglomeration in the free‐molecular regime. The fractal‐like dimension of ferromagnetic Cobalt agglomerates provides evidence that particles consisting of magnetic materials tend to form c.
State forecasting in electric power systems

The state vector of a power system varies with time owing to the dynamic nature of system loads. Therefore, it is necessary to establish a dynamic model for the time evolution of the state vector. The dynamic state estimation approach consists of predicting the state vector based on past estimations, followed by a filtering process performed when a new set of measurements is available. This paper presents a new algorithm for forecasting and filtering the state vector, using exponential smoothing and least-squares estimation techniques. The proposed algorithm is compared with another one based on standard Kalman filtering theory. Numerical results showing the performance for both dynamic estimators under different operational conditions are presented and discussed. Detection and identification of multiple bad data are also included. The new dynamic estimator exploiting state forecasting is extremely useful to real-time monitoring of power systems.
Experiments on rapidly rotating turbulent flows

A novel laboratory experiment for investigating statistically steady rotating turbulence is presented. Turbulence is produced nonintrusively by means of electromagnetic forcing. Depending on the rotation rate the Taylor-based Reynolds number is found to be in the range of 90≲Reλ≲240. Relevant properties of the turbulence, both with and without rotation, have been quantified with stereoscopic particle image velocimetry (SPIV). This method enables instantaneous measurement of all three velocity components in horizontal planes at a distance H from the bottom. The root-mean-square turbulent velocity decreases inversely proportional to H in the nonrotating experiments and is approximately constant when background rotation is applied. The integral length scale shows a weak H-dependence in the nonrotating experiments which is presumably due to the spatial extent of the forcing. Based on the behavior of the principal invariants of the Reynolds stress anisotropy tensor, the rotating turbulence has been characteriz.
Electromagnetic scattering by a uniaxially anisotropic sphere

The problem of electromagnetic scattering by a uniaxially anisotropic sphere is studied for both dielectric and absorbing cases. The fields of the TM ro ř wave inside a uniaxial sphere can be derived to be expressed in series of Bessel functions, as in the isotropic case, but with the order of function determined by the anisotropic ratio (AR = eθ/er). For the TE to ř wave, the uniaxial medium can be treated as an isotropic material characterised by eθ only, which is the permittivity parallel to the boundary surface of the medium. Wave propagation is not affected by the f directed permittivity. The effects of uniaxial anisotropy on the radar cross section (RCS) are also considered. It is found that the uniaxial anisotropy greatly influences the scattering behaviour of a spherical dielectric object. For an absorbing sphere, however, the uniaxial anisotropy no longer plays a significant role as in a dielectric sphere, and the dependance of the RCS on uniaxial anisotropy is found to be predictable. Details of theoretical treatment and numerical results are presented.