Miracle-dz/UniFAR-FTUs huggingface dataset:
TEMPERATURE AND MOISTURE DISTRIBUTIONS IN A MOIST SPHERICAL CAPILLARY-POROUS BODY : A NEW APPROACH

A novel technique, which is a combination of the Laplace transform and matrix calculus, is employed to obtain the exact solutions of the linearized Luikov system of coupled heat and moisture transport equations in a spherical capillary porous body addressed to specified initial and boundary conditions. It is shown that under certain restrictions, in the case of convective-type boundary conditions, the transcendental equation yields a countable number of complex conjugate roots. Here, a new computational scheme is employed, which evaluates real as well as a countable number of pairs of complex conjugate roots. A set of benchmark results is generated for the Luikov drying model, and in a way better than the alternative solutions proposed by Lobo et al. [19] for linear problems. Copyright © 1999 John Wiley & Sons, Ltd.
Age of immersion as a predictor of foreign accent

This study examined the relationship between Age of Immersion (AOI) and the Degree of Phonological Accent (DPA) that native‐English‐speaking judges perceived in the speech of Mandarin speakers who learned English as a second language. AOI and speech samples of variable length and linguistic context (single words, sentences, a short paragraph, and a self‐generated picture narration) were collected from the target group (n=32, AOI=3–16) and from native speaker controls (n=4, AOI=0). These were judged by a native speaker panel (n=14) using a continuous scale, along with measurements of confidence. Judging was broken over 3 separate visits. A set of similar samples and speakers was repeated at the onset and termination of the main rating task of each visit to ensure reliability. No single AOI was found for a ‘‘Critical Period’’ (CP). Instead, DPA was found to increase in a highly linear manner with AOI. In general, ratings of DPA began to increase at about AOI=5, maxing out as early as AOI=7, although near‐native ratings were given to some speakers whose AOI was greater than 5, especially in the case of female speakers. Thus DPA can be linearly predicted with AOI, though individual speakers are fairly variable after AOI=5.
Accuracy of Wind Fields Observed by a Bistatic Doppler Radar Network

The accuracy of wind vectors derived from bistatic dual-Doppler synthesis was investigated. The investigation was based on mathematical examinations and observation data analyses in both convective and stratiform cases. Accurate wind vectors were calculated within a range of 40 8, b , 1508, where b was the bistatic scatter angle. The accuracy is mainly governed by b as the first principle, while sidelobe contamination and the sensitivity of the low-gain bistatic antenna are practically the main obstacles in retrieving accurate wind fields in convective and stratiform echoes, respectively. The sidelobe contamination around strong convective echoes with large gradients of reflectivity can be eliminated by comparing the measured bistatic reflectivity and a clean bistatic radar reflectivity, which is derived from the measured transmitting radar reflectivity and a bistatic radar equation. The radar equation includes the bistatic resolution volume and a bistatic antenna pattern estimated by the longtime observation of stratiform echoes. The equation also leads to the distribution of minimum detectable reflectivity of the bistatic receiver. The multiple bistatic radar observation in stratiform echoes produced three kinds of horizontal wind vectors, which were almost coincident with each other, in the overdetermined region. The composite wind fields are calculated by a simple variational method.
LONG-TERM DYNAMICS OF THE COUPLED SUSPENSION BRIDGE SYSTEM

In this paper we study the long-term dynamics of a nonlinear suspension bridge system. The road bed and the main cable are modeled as a nonlinear beam and a vibrating string, respectively, and their coupling is carried out by one-sided springs. First, we scrutinize the set of stationary solutions, which turns out to be nontrivial when the axial load exceeds some critical value. Then, we prove the existence of a bounded global attractor of optimal regularity and we give its characterization in terms of the steady states of the problem.
On the stability of vertical double-diffusive interfaces. Part 1. A single plane interface

This is the first part of a three-part study of the stability of vertically oriented double-diffusive interfaces having an imposed vertical stable temperature gradient. Flow is forced by a prescribed jump of composition across the interfaces. Compositional diffusivity is ignored, while thermal diffusivity and viscosity are finite. In this first part, basic-state solutions are presented and discussed for three configurations: a single plane interface, two parallel interfaces and a circular cylindrical interface. The stability of a single plane interface is then analysed. It is shown that the presence of the compositional jump gives rise to a new type of three-dimensional instability which occurs for any non-zero forcing. This is in contrast to the thermally driven flow adjacent to a rigid wall, which is unstable only for a finite value of the forcing and results in the growth of a two-dimensional perturbation. The timescale for growth of the new instability is given by \[ \tau = \left[\frac{\nu \rho}{(\Delta \rho)_c}\right]^2\frac{\alpha}{\kappa g}\frac{{\rm d}T}{{\rm d}z}, \] where (Δρ)C is the prescribed jump in composition and dT/dz is the imposed temperature gradient. The influence of thermal diffusion is to enhance instability, while viscosity is stabilizing for nearly all wavenumbers. The interface is unstable for all finite wavenumbers if the Prandtl number is less than 1.472, while regions of stability in the wavenumber plane develop for small horizontal wavenumber and moderate vertical wavenumber for larger values of the Prandtl number. The neutral stability curves are investigated and the maximum growth rate of instability is identified for the whole range of values of the Prandtl number and its properties are elucidated by comparison with previous studies of flows near heated vertical walls.
Mitigating CCD radiation damage with charge injection: first flight results from Suzaku

The CCD detectors in the X-ray Imaging Spectrometers (XIS) aboard Suzaku have been equipped with a precision charge injection capability. The purposes of this capability are to measure and reduce the detector degradation caused by charged particle radiation encountered on-orbit. Here we report the first results from routine operation of the XIS charge injection function. After 12 months' exposure of the XIS to the on-orbit charged particle environment, charge injection already provided measurable improvements in detector performance: the observed width of the 5.9 keV line from the onboard calibration source was reduced from 205 eV to less than 145 eV. The rate of degradation is also significantly smaller with charge injection, so its benefit will increase as the mission progresses. Measured at 5.9 keV, the radiation-induced rate of gain degradation is reduced by a factor of 4.3 ± 0.1 in the front-illuminated sensors when injecting charge greater than 6 keV equivalent per pixel. The corresponding rate of degradation in spectral resolution is reduced by a factor 6.5 ± 0.3. Injection of a smaller quantity of injected charge in the back-illuminated XIS sensor produces commensurately smaller improvement factors. Excellent uniformity of the injected charge pattern is essential to the effectiveness of charge injection in the XIS.
The study strategies of small liberal arts college students before and after COVID-19

Research has clearly demonstrated that some study strategies (for example, self-testing and spaced studying) are effective, yet students often report studying ineffectively. Our focus with the current study is to update and extend the current literature on how college students study. We surveyed 484 introductory psychology students at a small liberal arts college—a different type of school from prior studies. Our survey built on an existing study strategies questionnaire used to assess a variety of student study behaviors and beliefs. Additionally, we asked new questions about multitasking and study scheduling. Overall, we found that the current sample reported studying in similar ways to what past research suggested; students used both effective and ineffective strategies, some of which correlated with grade point average (GPA). However, some differences emerged. For example, our students were more likely to report learning how to study from a teacher. Additionally, a majority of students believed that multitasking was ineffective, yet most reported multitasking while studying. Finally, an important, but exploratory, analysis demonstrated that study strategies were similar before and after COVID-19 forced classroom changes. We highlight the need for future research on study strategies to recruit participants from more diverse institutions.
Evaluation of arterial blood flow heterogeneity via an image-based computational model

A computational model of blood flow through the human pulmonary arterial tree has been developed to investigate the relative influence of branching structure and gravity on blood flow distribution in the human lung. A geometric model of the largest arterial vessels and definitions of the lobar boundaries were first derived using multi-detector row x-ray computed tomography (MDCT) scans from the Lung Atlas. Further accompanying arterial vessels were generated from the MDCT vessel end points into the lobar volumes using a volume filling branching algorithm. A reduced form of the Navier-Stokes equations were solved within the geometric model to simulate pressure, velocity and vessel radius throughout the network. Blood flow results in the anatomically-based model, with and without gravity, and in a symmetric arterial model were compared in order to investigate their relative contributions to blood flow heterogeneity. Results showed a persistent blood flow gradient and flow heterogeneity in the absence of gravitational forces in the anatomically-based model. Results revealed that the asymmetric branching structure of the model was largely responsible for producing this heterogeneity. Analysis of average results in different slice thicknesses illustrated a clear flow gradient due to gravity in 'lower-resolution’ data (thicker slices), but on examination of higher resolution data a trend was less obvious. Results suggest that while gravity does influence flow distribution, the influence of the tree branching structure is also a dominant factor. These results are consistent with high-resolution experimental studies that have demonstrated gravity to be only a minor determinant of blood flow distribution.
Coupling in amplitude variation with offset and the Wiggins approximation

ABSTRACTLinear amplitude-variation-with-offset (AVO) approximations, which experience a reduction in accuracy as elastic parameter contrasts become large, may be adjusted with second- and higher-order corrections. Corrective terms can be expressed in many ways, but they only serve a meaningful purpose if they provide the same qualitative interpretability as did the linearization. Some aspects of nonlinear AVO can be understood, quantitatively and qualitatively, in terms of coupling — the interdependence of elastic parameter contrasts amongst themselves in their determination of reflection strengths. Coupling, for instance, explains the weak but nonnegligible dependence of the converted wave reflection coefficient on the lower half-space P-wave velocity. This fact can be exposed by expanding the solutions of the Zoeppritz equations in a particular hierarchy of series. Also explainable through this approach is the mathematical importance of what is sometimes referred to as the “Wiggins approximation,” under.
Choosing between per-genotype, per-allele, and trend approaches for initial detection of gene–disease association

There are a number of approaches to detect candidate gene–disease associations including: (i) ‘per-genotype’, which looks for any difference across the genotype groups without making any assumptions about the direction of the effect or the genetic model; (ii) ‘per-allele’, which assumes an additive genetic model, i.e. an effect for each allele copy; and (iii) linear trend, which looks for an incremental effect across the genotype groups. We simulated a number of gene–disease associations, varying odds ratios, allele frequency, genetic model, and deviation from Hardy–Weinberg equilibrium (HWE) and tested the performance of each of the three methods to detect the associations, where performance was judged by looking at critical values, power, coverage, bias, and root mean square error. Results indicate that the per-allele method is very susceptible to false positives and false negatives when deviations from HWE occur. The linear trend test appears to have the best power under most simulated scenarios, but can sometimes be biased and have poor coverage. These results indicate that of these strategies a linear trend test may be best for initially testing an association, and the per-genotype approach may be best for estimating the magnitude of the association.
Spatio-temporal characteristics of self-pulse in hollow cathode discharge

The characteristics of self-pulse in hollow cathode discharge at low pressure have been investigated. The voltage-current (V-I) curves, the influence of ballast resistor on the self-pulses, and the evolution of current and voltage are measured. Both the axial and radial spatio-temporal discharge images of self-pulse are recorded. The results show that there exists the hysteresis effect in the present hollow cathode discharge. The high value of ballast resistors is favourable for the observation of self-pulses. The process of the self-pulse can be divided into three stages from the temporal discharge images, i.e., the pre-discharge, the transition from mainly axial electric field to mainly radial electric field, and the decaying process. The self-pulse is suggested to originate from the mode transition of the discharge in essence.
A comparative study of subgrid scale models in homogeneous isotropic turbulence

Recently, a number of studies have indicated that Large Eddy Simulation (LES) models are fairly insensitive to the adopted Subgrid Scale (SGS) models. In order to study this and to gain further insight into LES, simulations of forced and decaying homogeneous isotropic turbulence have been performed for Taylor Re numbers between 35 and 248 using various SGS models, representative of the contemporary state of the art. The predictive capability of the LES concept is analyzed by comparison with DNS data and with results obtained from a theoretical model of the energy spectrum. The resolved flow is examined by visualizing the morphology and by analyzing the distribution of resolved enstrophy, rate of strain, stretching, SGS kinetic energy, and viscosity. Furthermore, the correlation between eigenvalues of the resolved rate of strain tensor and the vorticity is investigated. Although the gross features of the flow appear independent of the SGS model, pronounced differences between the models become apparent whe.
M supergiants in the Milky Way and the Magellanic Clouds Colors, spectral types, and luminosities

On presente une nouvelle photometrie BVRI pour 116 candidates supergeantes rouges dans le Petit Nuage de Magellan et 11 supergeantes rouges lumineuses dans le Grand Nuage de Magellan. On presente egalement une nouvelle photometrie IR de 65 candidates supergeantes rouges dans le PNM et 96 dans le GNM. On donne la confirmation spectroscopique pour 65 des candidates du PNM. Les donnees obtenues sont combinees avec des donnees photometriques et spectroscopiques obtenues precedemment par Humphreys
Character contractibility of Banach algebras and homological properties of Banach modules

Abstract Let A be a Banach algebra and let φ be a nonzero character on A . We give some necessary and sufficient conditions for the left φ -contractibility of A as well as several hereditary properties. We also study relations between homological properties of some Banach left A -modules, the left φ-contractibility and the right φ-amenability of A . Finally, we characterize the left character contractibility of various Banach algebras related to locally compact groups.
Honest Exploration of Intractable Probability Distributions via Markov Chain Monte Carlo

Two important questions that must be answered whenever a Markov chain Monte Carlo (MCMC) algorithm is used are (Q1) What is an appropriate burn-in? and (Q2) How long should the sampling continue after burn-in? Developing rigorous answers to these questions presently requires a detailed study of the convergence properties of the underlying Markov chain. Consequently, in most practical applications of MCMC, exact answers to (Q1) and (Q2) are not sought. The goal of this paper is to demystify the analysis that leads to honest answers to (Q1) and (Q2). The authors hope that this article will serve as a bridge between those developing Markov chain theory and practitioners using MCMC to solve practical problems. The ability to address (Q1) and (Q2) formally comes from establishing a drift condition and an associated minorization condition, which together imply that the underlying Markov chain is geometrically ergodic. In this article, we explain exactly what drift and minorization are as well as how and why these conditions can be used to form rigorous answers to (Q1) and (Q2). The basic ideas are as follows. The results of Rosenthal (1995) and Roberts and Tweedie (1999) allow one to use drift and minorization conditions to construct a formula giving an analytic upper bound on the distance to stationarity. A rigorous answer to (Q1) can be calculated using this formula. The desired characteristics of the target distribution are typically estimated using ergodic averages. Geometric ergodicity of the underlying Markov chain implies that there are central limit theorems available for ergodic averages (Chan and Geyer 1994). The regenerative simulation technique (Mykland, Tierney and Yu, 1995; Robert, 1995) can be used to get a consistent estimate of the variance of the asymptotic normal distribution. Hence, an asymptotic standard error can be calculated, which provides an answer to (Q2) in the sense that an appropriate time to stop sampling can be determined. The methods are illustrated using a Gibbs sampler for a Bayesian version of the one-way random effects model and a data set concerning styrene exposure.
Inference on Structural Parameters In Instrumental Variables Regression With Weak Instruments

The authors consider the problem of making asymptotically valid inference on structural parameters in instrumental variables regression with weak instruments. Using local-to-zero asymptotics, they derive the asymptotic distributions of likelihood ratio (LR) and Lagrange multiplier (LM) type statistics for testing simple hypotheses on structural parameters based on maximum likelihood and generalized methods of moments estimation methods. In contrast to the nonstandard limiting behavior of Wald statistics, the limiting distributions of certain LR and LM statistics are bounded by a chi-square distribution with degrees of freedom given by the number of instruments.
Estimation in multi-path change-point problems

The current literature deals with the change-point problem only in the context of the obser¬vation of a single sequence. In this paper, inference will be based on the observation of TV sequences of random variables, each sequence containing one change-point. This extension allows the effective use of bootstrap and empirical Bayes methods, both of which are not feasible in the single-path context. Two classes of these “multi-path” change-point problems are considered. If the change-point is assumed to occur at the the same position in each sequence, then the terminology “fixed-tau multi-path change-point” will be used. In other cases, one may expect the change-point to occur at random positions in each sequence, according to some distribution, a “random-tau multi-path change-point” problem. Examples and simulations are given.
A model for large deformation of an ellipsoidal droplet with interfacial tension

A model is developed to predict the transient shape evolution of an ellipsoidal Newtonian droplet with interfacial tension, suspended in another Newtonian fluid with a different viscosity. Using the Eshelby equivalent inclusion theory [Eshelby (1957)], this model adds an approximate interfacial tension term to the exact deformation model of Wetzel and Tucker (2001) for droplets with zero interfacial tension. The model can predict large deformations and rotations of the ellipsoid, it allows any value of viscosity ratio, and it admits arbitrary far-field flows. The model does not incorporate breakup or coalescence. At viscosity ratios less than 0.1, the model blends the Eshelby model (for compact shapes) with a classical slender-body model (for thread-like shapes), providing a smooth transition between these two limits. The model accurately matches many experimental results from the literature, including steady shapes in simple shear, transient shapes during shear reversal, widening in simple shear, relaxat.
Surface Waves in Functionally Gradient Piezoelectric Plates

The hybrid numerical method, which has been proposed by the present authors for wave propagation analysis in anisotropic laminated plates, is extended for functionally gradient piezoelectric material (FGPM) plates. The properties of the plate changes continuously in the thickness direction. Characteristics of waves in the plates, and responses of the plates in the time and frequency domain are considered. A technique for calculating responses in the frequency domain is presented. Energy velocities, mode shapes of the waves in an FGPM plate, and the responses of the plate excited by mechanical loads and electrodes are computed. It is found that waves of lower modes in the FGPM plates for large wave numbers appear as surface waves and that a strong surface wave is excited on the softer surface of the FGPM plate. These surface waves can be expected to be used in surface acoustic wave devices.
Lipschitz stability for a hyperbolic inverse problem by finite local boundary data

In this article we consider the inverse problem of determining the potential q in a wave equation in a bounded smooth domain Ω in from a finite number of data of the hyperbolic Dirichlet to Neumann map and we prove the Lipschitz stability in determining q. Our main result is stated as follows. Let T> diam Ω and Γ0⊂∂Ω. For any k-dimensional space X in L ∞(Ω), there exist 2k-functions f 1, …, f 2k on (0,T)×∂Ω such that , provided that q1, q2∈X are uniformly bounded in a suitable Sobolev space. Here Λq is the Dirichlet to Neumann map for the coefficient q(x).