Miracle-dz/UniFAR-FTUs huggingface dataset:
An analytical method for vibration analysis of cylindrical shells coupled with annular plate under general elastic boundary and coupling conditions

A unified solution for coupled cylindrical shell and annular plate systems with general boundary and coupling conditions is presented in the study by using a modified Fourier-Ritz method. Under the framework, regardless of the boundary and continuity conditions, each displacement for the cylindrical shell and the annular plate is invariantly expressed as the modified Fourier series composed of the standard Fourier series and auxiliary functions. The introduction of the auxiliary functions can not only remove the potential discontinuities at the junction and the extremes of the combination but also accelerate the convergence of the series expansion. All the expansion coefficients are determined by the Rayleigh-Ritz method as the generalized coordinates. The arbitrary axial position of the annular plate coupling with the cylindrical shell considered in the theoretical formulation makes the present method more general. The theoretical model established by present method can be conveniently applied to cylindrical shell-circular plate combinations just by varying the inner radius of the annular plate. The convergence and accuracy of present method are tested and validated by a number of numerical examples for coupled annular plate-cylindrical shell structures with various boundary restraints and general elastic coupling conditions. The effects of the axial position of the annular plate and elastic coupling conditions on the vibration behavior of the coupled system are also investigated. The power of present method compared to conventional finite element method is demonstrated with less computation cost. Some new results are presented to provide useful information for future researchers.
A meshfree method for fully coupled analysis of flow and deformation in unsaturated porous media

A meshfree algorithm is proposed for the fully coupled analysis of flow and deformation in unsaturated poro‐elastic media. A brief description of the governing differential equations is presented followed by the spatial discretization of the governing equations using the Galerkin approach and the radial point interpolation method. Temporal discretization is achieved using a three‐point approximation technique with second order accuracy. Particular attention is given to the determination of constitutive coefficients and effective stress parameters of the medium taking into account hydraulic hysteresis. Application of the model to several experimental data is demonstrated. Good agreement is obtained between the numerical and experimental results in all cases highlighting the ability of the proposed model in capturing the volume change and suction dependency of the model parameters as well as the coupled behaviour of unsaturated porous media subject to hydraulic hysteresis. Copyright © 2012 John Wiley & Sons, Ltd.
A Continuous Time Approximation to the Unstable First-Order Autoregressive Process: The Case without an Intercept

We consider a first-order autoregression with i.i. d. errors and a fixed initial condition. The asymptotic distribution of the normalized least-squares estimator as the sampling interval converges to zero is shown to be the same as the exact distribution of the continuous-time estimator in an Ornstein-Uhlenbeck process. This asymptotic distribution permits explicit consideration of the effect of the initial condition. The appropriate moment-generating function is derived and used to tabulate the limiting distribution and probability density functions, the moments and some power functions. The adequacy of this asymptotic approximation is found to be excellent for values of the autoregressive parameter near one and any fixed initial condition. Copyright 1991 by The Econometric Society.
On growth-optimal tax rates and the issue of wealth inequalities

We consider a highly stylized, yet non trivial model of the economy, with a public and private sector coupled through a wealth tax and a redistribution policy. The model can be fully solved analytically, and allows one to address the question of optimal taxation and of wealth inequalities. We find that according to the assumption made on the relative performance of public and private sectors, three situations are possible. Not surprisingly, the optimal wealth tax rate is either 0% for a deeply dysfunctional government and/or highly productive private sector or 100% for a highly efficient public sector and/or debilitated/risk averse private investors. If the gap between the public/private performance is moderate, there is an optimal positive wealth tax rate maximizing economic growth, even—counter-intuitively—when the private sector generates more growth. The compromise between profitable private investments and taxation, however, leads to a residual level of inequalities. The mechanism leading to an optimal growth rate is akin to the well-known explore/exploit trade-off.
The luminosity of the Galactic Center

High signal-to-noise 50- and 90-micron continuum maps of the central 5 x 4 arcmin of the Galaxy made from observations on the Kuiper Airborne Observatory are presented. Dust and luminosity distribution models which are consistent with the data are presented. These data are consistent with a flared disk of dust, centered on the position of Sgr A*, having a central cavity wth a radius of 1 pc. Strong evidence is found for a large amount of dust between the northern and eastern ionized arms located within the cavity. It is argued that this 'tongue' of dust is optically thick at UV and visible wavelengths. Both smooth and clumped dust distributions, consistent with the disk and central cavity, are considered. For the smooth distribution, the dust heating is found to be consistent with the data only for a central UV source of a few x 10 exp 6 solar luminosities.
The initial permeability of polycrystalline MnZn ferrites: The influence of domain and microstructure

The validity of nonmagnetic grain‐boundary (NMGB) models for the initial permeability of polycrystalline ferrites is examined. The domain size in a series of wet‐chemically prepared polycrystalline MnZn ferrites, in the demagnetized state, has been determined by neutron depolarization. A transition in the intragranular domain structure from mono‐ to two domain is observed at grain size D≊4 μm. An expression for this transition has been derived for a dense magnetic material. The grain size dependence of the initial permeability of the ferrites studied, particularly for monodomain grains, is consistent with the NMGB model. The grain‐boundary width and composition have been determined with a nanoprobe (1.5 nm resolution). Composition variations extend ≊10 nm into the grain. The findings suggest that, although the NMGB model considers ‘‘nonmagnetic’’ grain boundaries, in practice the grain boundary may be hard magnetic.
A Simple Microstrip Bandpass Filter with Analytical Design Theory and Sharp Skirt Selectivity

A simple coupled-line circuit configuration is proposed to design microstrip bandpass filter with sharp skirt selectivity in this paper. This novel circuit consists of two-section coupled lines with a common connected point. An equivalent odd-mode and even-mode analysis is applied to analyze transmission and reflection property, and the effective analytical scattering parameters' expressions are achieved. Design curves for this novel bandpass filter are given while six typical numerical examples are presented. The presented simulation results show that the reflection zeros in pass band and transmission zeros in stop band can be tuned by changing the even- and odd-mode characteristic impedances of these coupled lines. Finally, two microstrip bandpass filters with different transmission and reflection zeros are fabricated, measured and compared. The experimental results show excellent bandpass filtering property with sharpened rejection skirts and low insertion loss.
The Shape and Figure Rotation of the Dark Halo of NGC 2915

NGC 2915 is a blue compact dwarf galaxy with a very extended H I disk. This disk shows a short central bar and extended spiral arms, both reaching far beyond the optical component. We use Tremaine & Weinberg's method to measure the pattern speed of the bar and spiral arms from H I radio synthesis data. Our measurements yield a pattern speed Ωp = 0.21 ± 0.06 km s-1 arcsec-1 (8.0 ± 2.4 km s-1 kpc-1 for D = 5.3 kpc), in disagreement with the general view that corotation in barred disks lies just outside the end of the bar, but consistent with recent models of barred galaxies with dense dark matter halos. Our adopted bar semilength, rb ≈ 180″, puts corotation at more than 1.7rb. The existence of the pattern is also problematic. Because NGC 2915 is isolated, gravitational interactions cannot account for the structure observed in the H I disk. We also demonstrate that the low surface density observed in the disk and the location of the pseudorings make it unlikely that swing amplification or bar-driven spiral arms could explain the bar and spiral pattern. Based on the similarity of the dark matter and H I surface density profiles, we discuss the possibility of dark matter distributed in a disk and following closely the H I distribution. This disk then becomes gravitationally unstable and can naturally form a bar and spiral pattern. However, this explanation is difficult to reconcile with some properties of NGC 2915. We also consider the effect of a massive and extended triaxial dark matter halo with a rotating figure. The existence of such halos is supported by cold dark matter simulations showing strongly triaxial dark halos with slow figure rotation. The observed structure of the H I disk can then arise through forcing by the rotating triaxial figure. We associate the measured pattern speed in NGC 2915 with the figure rotation of its dark halo.
Regularity of BMO weak solutions to nonlinear parabolic systems via homotopy

for all φ ∈ C c (Q,R). Here, we write dz = dxdt and W 1,0 2 (Q,R ) is the set of vector-valued functions whose spatial weak derivatives are in L(Q). It is now a classical result (see [10, 16]) for the scalar case (m = 1) that bounded weak solutions to (1.1) are Hölder continuous and if A,F are sufficiently smooth, then bounded weak solutions are classical. On the other hand, in the case of systems of equations (i.e. m > 1), one cannot generally expect bounded weak solutions of (1.1) to be Hölder continuous everywhere (see counterexamples, e.g., in [5]). Partial regularity theory for (1.1), when A is linear in Du, was considered in [2, 3], where it was shown that bounded weak solutions are Hölder continuous on a full measure subset of Q and the Hausdörff dimension of their singular sets could be estimated. In a recent work, see [11, 14], we introduced the so-called linear A-heat approximation technique to investigate partial and everywhere regularity for degenerate parabolic systems. However, as pointed out in [1], it is crucial to establish everywhere Hölder continuity for bounded weak solutions for systems and to control their Hölder norms in order to discuss further important questions in applications (e.g.; see [18]) such as global existence and dynamics of the solutions. Works in these directions were reported in [6, 7, 8, 12, 17, 20] for systems satisfying
Measurements of polarimetric sensitivity to temperature in birefringent holey fibres

We measured spectral dependence of the polarimetric sensitivity to temperature in three birefringent holey fibres with different geometries. Our results show that thermal properties of the birefringent photonic crystal fibres depend very much on the air hole arrangement. Using the procedure which allows us to determine the sign of temperature sensitivity, we demonstrated that one of the investigated fibres is insensitive to temperature at a certain wavelength. We also measured the temperature sensitivities for the fibres with and without polymer coating and showed that the coating changes significantly the fibre response to temperature. Furthermore, we demonstrated experimentally that the spectral dependence of the polarimetric sensitivity to temperature in birefringent holey fibres obeys a scaling law.
Déformations de connexions localement plates

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The First Flare Observation with a New Solar Microwave Spectrometer Working in 35–40 GHz

The microwave spectrum contains valuable information about solar flares. Yet, the present spectral coverage is far from complete and broad data gaps exist above 20 GHz. Here we report the first flare (the X2.2 flare on 2022 April 20) observation of the newly built Chashan Broadband Solar millimeter spectrometer (CBS) working from 35 to 40 GHz. We use the CBS data of the new Moon to calibrate, and the simultaneous NoRP data at 35 GHz to cross-calibrate. The impulsive stage has three local peaks with the middle one being the strongest and the maximum flux density reaches ∼9300 solar flux unit at 35–40 GHz. The spectral index of the CBS data (α C) for the major peak is mostly positive, indicating the gyrosynchrotron turnover frequency (ν t ) goes beyond 35–40 GHz. The frequency ν t is smaller yet still larger than 20 GHz for most of the other two peaks according to the spectral fittings with NoRP-CBS data. The CBS index manifests the general rapid-hardening-then-softening trend for each peak and gradual hardening during the decay stage, agreeing with the fitted optically thin spectral index (α tn) for ν t < 35 GHz. In addition, the obtained turnover frequency (ν t ) during the whole impulsive stage correlates well with the corresponding intensity (I t ) according to a power-law dependence ( It∝νt4.8 ) with a correlation coefficient of 0.82. This agrees with earlier studies on flares with low turnover frequency (≤17 GHz), yet it is being reported for the first time for events with a high turnover frequency (≥20 GHz).
Implications of gradient flow on the static force

We use gradient flow to compute the static force based on a Wilson loop with a chromoelectric field insertion. The result can be compared on one hand to the static force from the numerical derivative of the lattice static energy, and on the other hand to the perturbative calculation, allowing a precise extraction of the $\Lambda_0$ parameter. This study may open the way to gradient flow calculations of correlators of chromoelectric and chromomagnetic fields, which typically arise in the nonrelativistic effective field theory factorization.
Analyzing Riemann's hypothesis

In this paper we perform a detailed analysis of Riemann's hypothesis, dealing with the zeros of the analytically-extended zeta function. We use the functional equation $\zeta(s) = 2^{s}\pi^{s-1}\sin{(\displaystyle \pi s/2)}\Gamma(1-s)\zeta(1-s)$ for complex numbers $s$ such that $0<{\rm Re(s)}<1$ and the reduction to the absurd method where we use an analytical study based on a complex function and its modulus as a real function of two real variables in combination with a deep numerical analysis to show that the real part of the non-trivial zeros of the Riemann zeta function is equal to $1/2$ to the best of our resources. This is done in two steps. Firstly, we show what would happen if we assumed that the real part of $s$ has a value between $0$ and $1$ but different from $1/2$ arriving at a possible contradiction for the zeros. Secondly assuming that there is no real value $y$ such that $\zeta\left(1/2 +yi \right)=0$ by applying the rules of logic to negate a quantifier and the corresponding Morgan's law we also arrive to a plausible contradiction. Finally, we analyze what conditions should be satisfied by $y \in \mathbb R$ such that $\zeta(\displaystyle 1/2 +yi)=0$. While these results are valid to the best of our numerical calculations, we do not observe and foresee any tendency for a change. Our findings open the way towards assessing the validity of Riemman's hypothesis from a fresh and new mathematical perspective.
Universal thermodynamic bounds on symmetry breaking in biochemical systems

Living systems are maintained out-of-equilibrium by external driving forces. At stationarity, they exhibit emergent selection phenomena that break equilibrium symmetries and originate from the expansion of the accessible chemical space due to non-equilibrium conditions. Here, we use the matrix-tree theorem to derive universal thermodynamic bounds on these symmetry-breaking features in biochemical systems. Our bounds are independent of the kinetics and hold for both closed and open reaction networks. We also extend our results to master equations in the chemical space. Using our framework, we recover the thermodynamic constraints in kinetic proofreading. Finally, we show that the contrast of reaction-diffusion patterns can be bounded only by the non-equilibrium driving force. Our results provide a general framework for understanding the role of non-equilibrium conditions in shaping the steady-state properties of biochemical systems.
Sensing microscopic noise events by frequent quantum measurements

We propose and experimentally demonstrate a general method allowing us to unravel microscopic noise events that affect a continuous quantum variable. Such unraveling is achieved by frequent measurements of a discrete variable coupled to the continuous one. The experimental realization involves photons traversing a noisy channel. There, their polarization, whose coupling to the photons spatial wavepacket is subjected to stochastic noise, is frequently measured in the quantum Zeno regime. The measurements not only preserve the polarization state, but also enable the recording of the full noise statistics from the spatially-resolved detection of the photons emerging from the channel. This method proves the possibility of employing photons as quantum noise sensors and robust carriers of information.
Parametric post-processing of dual-resolution precipitation forecasts

Recently, all major weather centres issue ensemble forecasts, which differ both in ensemble size and spatial resolution – even while covering the same domain. These parameters directly determine both the forecast skill of the prediction and the computation cost. In the last few years, the plans of upgrading the configuration of the Integrated Forecast System of the European Centre for Medium-Range Weather Forecasts (ECMWF) from a single forecast with 9 km resolution and a 51-member ensemble with 18 km resolution induced an extensive study of the forecast skill of both raw and post-processed dual-resolution predictions comprising ensemble members of different horizontal resolutions. We investigate the predictive performance of the censored shifted gamma (CSG) ensemble model output statistic (EMOS) approach for statistical post-processing with the help of dual-resolution 24h precipitation accumulation ensemble forecasts over Europe with various forecast horizons. We consider the operational 50-member ECMWF ensemble as high-resolution and extend it with a low-resolution (29-km grid) 200-member experimental forecast. The investigated dual-resolution combinations consist of subsets of these two forecast ensembles with equal computational cost, which is equivalent to the cost of the operational ensemble. Our case study verifies that, compared with the rawensemble combinations, EMOSpost-processing results in a significant improvement in forecast skill and that skill is statistically indistinguishable between any of the analysed mixtures of dual-resolution combinations. Furthermore, the semilocally trained CSG EMOS provides an efficient alternative to the state-of-the-art quantile mapping without requiring additional historical data.
The cyclotomic numbers of order seven

The cyclotomic numbers of order seven are given in terms of the solutions of a certain system of three quadratic diophantine equations. This is analogous to L. E. Dickson's evaluation of the cyclotomic numbers of order five, and is a convenient approach for applications to the theory of power residues.
A source of entangled photons based on a cavity-enhanced and strain-tuned GaAs quantum dot

A quantum-light source that delivers photons with a high brightness and a high degree of entanglement is fundamental for the development of efficient entanglement-based quantum-key distribution systems. Among all possible candidates, epitaxial quantum dots are currently emerging as one of the brightest sources of highly entangled photons. However, the optimization of both brightness and entanglement currently requires different technologies that are difficult to combine in a scalable manner. In this work, we overcome this challenge by developing a novel device consisting of a quantum dot embedded in a circular Bragg resonator, in turn, integrated onto a micromachined piezoelectric actuator. The resonator engineers the light-matter interaction to empower extraction efficiencies up to 0.69(4). Simultaneously, the actuator manipulates strain fields that tune the quantum dot for the generation of entangled photons with fidelities up to 0.96(1). This hybrid technology has the potential to overcome the limitations of the key rates that plague current approaches to entanglement-based quantum key distribution and entanglement-based quantum networks. Introduction
Detection of Solar Filaments Using Suncharts from Kodaikanal Solar Observatory Archive Employing a Clustering Approach

With over 100 yr of solar observations, the Kodaikanal Solar Observatory (KoSO) is a one-of-a-kind solar data repository in the world. Among its many data catalogs, the “suncharts” at KoSO are of particular interest. These suncharts (1904–2020) are colored drawings of different solar features, such as sunspots, plages, filaments, and prominences, made on papers with a Stonyhurst latitude–longitude grid etched on them. In this paper, we analyze this unique data by first digitizing each sunchart using an industry-standard scanner and saving those digital images in a high-resolution “. tif” format. We then examine cycle 19 and cycle 20 data (two of the strongest cycles of the last century) with the aim of detecting filaments. To this end, we employed the “K-means clustering” method, and obtained different filament parameters such as position, tilt angle, length, and area. Our results show that filament length (and area) increases with latitude and the poleward migration is clearly dominated by a particular tilt sign. Lastly, we cross verified our findings with results from KoSO digitized photographic plate database for the overlapping time period and obtained a good agreement between them. This work, acting as a proof-of-the-concept, will kickstart new efforts to effectively use the entire hand-drawn series of multifeature, full-disk solar data and enable researchers to extract new sciences, such as the generation of pseudomagnetograms for the last 100 yr.
Distributed Random Block-Coordinate descent methods for ill-posed composite convex optimisation problems

We develop a novel randomised block coordinate descent primal-dual algorithm for a class of non-smooth ill-posed convex programs. Lying in the midway between the celebrated Chambolle-Pock primal-dual algorithm and Tseng’s accelerated proximal gradient method, we establish global convergence of the last iterate as well optimal O (1 /k ) and O (1 /k 2 ) complexity rates in the convex and strongly convex case, respectively, k being the iteration count. Motivated by distributed and data-driven control of power systems, we test the performance of our method on a second-order cone relaxation of an AC-OPF problem. Distributed control is achieved via the distributed locational marginal prices (DLMPs), which are obtained dual variables in our optimisation framework.