Miracle-dz/UniFAR-FTUs huggingface dataset:
Vortices in high-temperature superconductors

With the high-temperature superconductors a qualitatively new regime in the phenomenology of type-II superconductivity can be accessed. The key elements governing the statistical mechanics and the dynamics of the vortex system are (dynamic) thermal and quantum fluctuations and (static) quenched disorder. The importance of these three sources of disorder can be quantified by the Ginzburg number $Gi=\frac{{(\frac{{T}_{c}}{{H}_{c}^{2}}\ensuremath{\varepsilon}{\ensuremath{\xi}}^{3})}^{2}}{2}$, the quantum resistance $Qu=(\frac{{e}^{2}}{\ensuremath{\hbar}})(\frac{{\ensuremath{\rho}}_{n}}{\ensuremath{\varepsilon}\ensuremath{\xi}})$, and the critical current-density ratio $\frac{{j}_{c}}{{j}_{o}}$, with ${j}_{c}$ and ${j}_{o}$ denoting the depinning and depairing current densities, respectively (${\ensuremath{\rho}}_{n}$ is the normal-state resistivity and ${\ensuremath{\varepsilon}}^{2}=\frac{m}{M}l1$ denotes the anisotropy parameter). The material parameters of the oxides conspire to produce a large Ginzburg number $\mathrm{Gi}\ensuremath{\sim}{10}^{\ensuremath{-}2}$ and a large quantum resistance $\mathrm{Qu}\ensuremath{\sim}{10}^{\ensuremath{-}1}$, values which are by orders of magnitude larger than in conventional superconductors, leading to interesting effects such as the melting of the vortex lattice, the creation of new vortex-liquid phases, and the appearance of macroscopic quantum phenomena. Introducing quenched disorder into the system turns the Abrikosov lattice into a vortex glass, whereas the vortex liquid remains a liquid. The terms "glass" and "liquid" are defined in a dynamic sense, with a sublinear response $\ensuremath{\rho}={\frac{\ensuremath{\partial}E}{\ensuremath{\partial}j}|}_{j\ensuremath{\rightarrow}0}$ characterizing the truly superconducting vortex glass and a finite resistivity $\ensuremath{\rho}(j\ensuremath{\rightarrow}0)g0$ being the signature of the liquid phase. The smallness of $\frac{{j}_{c}}{{j}_{o}}$ allows one to discuss the influence of quenched disorder in terms of the weak collective pinning theory. Supplementing the traditional theory of weak collective pinning to take into account thermal and quantum fluctuations, as well as the new scaling concepts for elastic media subject to a random potential, this modern version of the weak collective pinning theory consistently accounts for a large number of novel phenomena, such as the broad resistive transition, thermally assisted flux flow, giant and quantum creep, and the glassiness of the solid state. The strong layering of the oxides introduces additional new features into the thermodynamic phase diagram, such as a layer decoupling transition, and modifies the mechanism of pinning and creep in various ways. The presence of strong (correlated) disorder in the form of twin boundaries or columnar defects not only is technologically relevant but also provides the framework for the physical realization of novel thermodynamic phases such as the Bose glass. On a macroscopic scale the vortex system exhibits self-organized criticality, with both the spatial and the temporal scale accessible to experimental investigations.
Heuristics for multilevel lot-sizing with a bottleneck

In this paper we present a heuristic method, based on Lagrangian relaxation, for multilevel lot-sizing when there is a single bottleneck facility. A series of Lagrangian relaxations one for each item in the product structure is imbedded in a branch and bound procedure. The objective is to find a production schedule that fits within available capacity at minimum cost. The method has two solution phases, dual and primal. In the dual phase of the procedure, implied costs of setups and production are determined based on a tentative schedule. The primal phase is repeated with these new prices and we iterate to reach a good solution. The solution procedure is first tested on two special cases: uncapacitated multilevel lot-sizing and the capacitated, single-level multi-item lot sizing problem. The results show that the solution procedure can provide better solutions than some heuristics designed especially for those problems. Test results on the bottleneck problem indicate that good feasible solutions are found for problems too difficult to solve with exact methods.
An Effective Image Edge Detection Algorithm – Fuzzy Box-Counting

Edge detection plays an important role in computer vision and image processing. Fractal and Fuzzy theory show significant effect in the edge detection and have attracted much attention. Compared with traditional edge detection methods, this paper proposes a Fuzzy Box-counting Dimension Method (FBDM). This algorithm introduces the pre-judging mechanism to improve the speed of image segmentation, and the self-adaptive dimension threshold and the voting mechanism under multi-windows to improve the accuracy of the determination of edge points. Finally, closest principle is used to clear edge and reduce noise. Experimental results show FBDM can improve the precision of image edge detection effectively without pretreatment, and it has a very superior de-noising performance.
Lessons from the Regulation of E-scooters through the MDS Standard: Policy Lessons for Connected Vehicles

Connected vehicles generate new data streams that present promising opportunities for policymakers to monitor and learn from events and behavior. To explore what we can learn from how public entities leverage ubiquitous data streams for policy development and enforcement, we draw on a case study of the standard Mobility Data Specification (MDS) and its use by cities to regulate E-scooter operators. Our findings suggest that (1) the richness of real-time data changes the speed of policy revision, (2) data access enables moving some micro-decisions to the edge, and (3) policy will be formulated as fixed or flexible with different amendment rules.
VoRF: Volumetric Relightable Faces

Portrait viewpoint and illumination editing is an important problem with several applications in VR/AR, movies, and photography. Comprehensive knowledge of geometry and illumination is critical for obtaining photorealistic results. Current methods are unable to explicitly model in 3 D while handing both viewpoint and illumination editing from a single image. In this paper, we propose VoRF, a novel approach that can take even a single portrait image as input and relight human heads under novel illuminations that can be viewed from arbitrary viewpoints. VoRF represents a human head as a continuous volumetric field and learns a prior model of human heads using a coordinate-based MLP with individual latent spaces for identity and illumination. The prior model is learnt in an auto-decoder manner over a diverse class of head shapes and appearances, allowing VoRF to generalize to novel test identities from a single input image. Additionally, VoRF has a reflectance MLP that uses the intermediate features of the prior model for rendering One-Light-at-A-Time (OLAT) images under novel views. We synthesize novel illuminations by combining these OLAT images with target environment maps. Qualitative and quantitative evaluations demonstrate the effectiveness of VoRF for relighting and novel view synthesis, even when applied to unseen subjects under uncontrolled illuminations.
Finite-size effects in the electrical transport properties of single bismuth nanowires

Single bismuth nanowires with diameters ranging between 150nm and 1μm were fabricated by electrochemical deposition in single-pore membranes. Using three different parameter sets of temperature and voltage, three groups of wires, each with a different mean grain size, were created. By measuring the electrical resistance of each nanowire individually, resistance-versus-diameter data enable us to assort the Bi nanowires in three different groups characterized by three distinct mean specific electrical resistivities. Each of these three groups is also characterized by a common mean grain size predetermined by the correspondent set of deposition parameters. Thus the results demonstrate that the resistivity is determined mainly by electron scattering at grain boundaries. Resistance-versus-temperature curves display a nonmonotonic behavior. The calculated charge carrier mobility saturates at low temperatures and is one to two orders of magnitude smaller than in bulk material depending on wire diameter and cryst.
Identifying intrinsic variability in multivariate systems through linearized inverse methods

A growing number of industrial risk studies include probabilistic treatment of the numerous sources of uncertainties. In the uncertainty treatment framework considered in this article, the intrinsic input variability is modelled by a multivariate probability distribution, though only outputs of the physical model may be observed. The objective is to identify a probability distribution, the dispersion of which is independent of the sample size since intrinsic variability is at stake. In order to limit to a reasonable level, the number of (usually large CPU-consuming) physical model runs inside the inverse algorithms, and the linearized Gaussian framework is investigated within this article. First, a simple criterion is exhibited to ensure the identifiability of the model. Then, the inverse problem is re-interpreted as a statistical estimation problem with missing data structure. Hence, EM-type algorithms may be tested, and the expectation-conditional maximization either variant evidences advantages in overcoming the possible pathology of slow convergence which affects the standard EM algorithm. The estimation quality, as suggested through a ratio of epistemic uncertainty to intrinsic variability, proves to be closely linked to classical sensitivity indices. Numerical experiments on simulated and real data sets in nuclear thermal hydraulics highlight the good performances of these algorithms, provided an adequate parametrization with respect to identifiability.
Window Estimation of the Asymptotic Variance of Rank Estimators of Location.

Abstract : Estimates of location based on rank statistics and score functions are receiving considerable attention in studies of 'robust' statistics. When using such estimates, one frequently would also like to have an estimate of the variance of a Normal distribution to Studentize the mean. The paper proposes a window estimator for the principal part of the asymptotic variance. (Modified author abstract)
H-Bus: an experimental ATM-based optical premises network

An optical customer premises network (CPN), called H-Bus, designed to interface future broadband ISDN signals and distribute available bandwidth to terminal equipment connected to the CPN, is discussed. Key features of this network are the use of optical fiber as a transmission medium and a hybrid architecture, namely, a broadcast bus for the downstream (network interface to subscriber terminal) and a looped bus for the upstream (subscriber terminal to network interface) traffic. The physical layer of the network makes use of the synchronous optical network (SONET) transmission format. The user information is carried using the asynchronous transfer mode (ATM) technique. The reliability of H-Bus is improved through the use of a network component called an optical protection socket (OPS). This is an automatic optical bypass switch that protects the CPN in the case of individual node failures. To resolve any access contention on the upstream bus, a multipriority media access control protocol has been defined. Its performance is compared with that of protocols used in other high-speed local area networks. >
Collisional Excitation Transfer between Atoms in the Resonant Process

The excitation transfers through collision between hydrogen atoms and between other simple identical atoms are considered theoretically by an impact parameter method. A rotating atom approximation and a fixed atom approximation (concerned with the direction of electronic polarization) are applied to the problem. The cross-section for the transfer of the excitation (2 p 2 P ) of a hydrogen atom with thermal velocity (kinetic energy of 0.025 ev) to the other hydrogen atom in the ground state is estimated to be 3065 A 2 with the rotating atom approximation and 680 A 2 with the fixed atom approximation. In the case of helium atoms, the cross-section for the transfer of the excitation (2 p 1 P ) is also estimated to be 606.7 A 2 with thermal velocity.
Log-Shifted Gamma Approximation to Lognormal Sum Distributions

This paper proposes the log-shifted gamma (LSG) approximation to model the sum of M lognormally distributed random variables (RVs). The closed-form probability density function of the resulting LSG RV is presented, and its parameters are directly derived from those of the M individual lognormal RVs by using an iterative moment-matching technique without the need for curve fitting of computer-generated distributions. Simulation and analytical results on the cumulative distribution function (cdf) of the sum of M lognormal RVs in different conditions indicate that the proposed LSG approximation can provide better accuracy than other lognormal approximations over a wide cdf range, especially for large M and/or standard deviation.
M ODELLING AND SIMULATION OF A DHESION OF THE RAIL VEHICLE

 In the paper we consider the issue related to the phenomenon of wheel-to-rail adhesion. This issue concerns self- excited vibrations in the area of wheel-rail contact, caused by unstable friction. Such friction is characterized by decreasing values of the friction coefficient with increasing slipping velocity. The paper includes mathematical formulation of the problem and presents the method for solving it. In addition, a simulation of elementary vehicle driving was performed. During the simulation, self-excited vibrations arose during wheel slip caused by high driving torque. The paper presents graphs illustrating the tangential force and the slipping velocity during these vibrations.
Mössbauer spectra of ferrofluids characterized using a many state relaxation model for superparamagnets

Using a many-state relaxation formalism and combining it with an accurate expression for the relaxation time of single-domain ferromagnetic particles and a log-normal size distribution we are able to fit Mossbauer spectra which span temperatures from where a pure hyperfine field distribution is present to where a single broad line occurs due to high relaxation rates. With this model, we have fitted the Mossbauer spectra of two Fe3O4 ferrofluids, from 12 to 180 K. Fits to the ferrofluid with a mean particle size of 4.5 nm yield an anisotropy energy (K) of 3.0±0.1×104 J/m3 with the onset of magnetic relaxation at 30±5 K while data for a mean particle size of 6.0 nm give K=2.4±0.2×104 J/m3 with magnetic relaxation starting at 55±5 K. These blocking temperatures agree with those extrapolated from frequency dependent χac data.
Gesture and Part-of-Speech Alignment in Dialogues

This paper studies the relation between language and gesture in interaction by investigating the temporal alignment of gestures and the words they co-occur with in a corpus of taskbased dialogues. Specifically, we examine the relationship of different semiotic gesture types (their quantity and duration) with the syntactic categories assigned to the words that coincide with the gesture. We observe that different types of gesture-word alignment present different distributions, as well as different associations depending on the gesture type.
Effect of M-QAM Modulation Technique for a Converged Network Infrastructure Radio over Fiber ( RoF )

The objective of the research is to analyze, at the simulation level, the effect of the M -Quadrature Amplitude Modulation ( M-QAM ) technique, in the downlink, for a converged Radio over Fiber ( RoF ) network infrastructure, implementing the Ortho-gonal Frequency Division Multiplexing (OFDM) technique and the Passive Optical Network architecture, with 10 Gbps capacity ( XG-PON ). The evaluation of the effect of the M-QAM modulation technique was done through a pre-established simulation methodology and using the optsim software for the network model and tests. In the results of the research, the increase of the order of M-QAM modulation for a converged OFDM-RoF network infrastructure allows to represent more bits per symbol, however, it requires a higher transmission power. The conclusion derives in the possibility of developing a robust converged OFDM-RoF network infrastructure of XG-PON type, implementing the M-QAM technique, since it efficiently uses the available bandwidth.
Effect of slickwater-alternate-slurry injection on proppant transport at ﬁ eld scales: A hybrid approach combining experiments and deep learning

Proppant transport in underground fractures plays a key role in mitigating sand screen-out and enhancing the stimulated production for hydraulic fracturing. The effects of ﬁ eld pumping schedules, however, are not fully studied. We investigate the effect of slickwater-alternate-slurry injection on proppant transport at ﬁ eld-practical scales. A new hybrid approach is proposed to directly connect experimental studies with ﬁ eld operations, which consists of observation experiments, calculations, and deep learning (DL) work ﬂ ow. The experiments reveal that the alternate injection induces the unexpected proppant ridge. The modi ﬁ ed calculations (considering the ridge height) are proposed to extract features for training the DL algorithm. The work ﬂ ow predicts the downhole pressure (mainly governed by proppant injection) for error analyses. Approximately 20.2% of the error is eliminated by considering the proppant ridge, thus demonstrating its effect on proppant injection. The predictions are signi ﬁ cantly improved in early and late periods of fracturing operations when the fracture is initially created and highly ﬁ lled. The sensitivity analysis suggests that the pump rate may dominate the ridge height compared with other hydraulic parameters. The study of proppant ridge complements the mechanisms of proppant transport, which is essential for controlling fracturing pressure and boosting the proppant injection. © 2021 Published by Elsevier Ltd.
Cesium and potassium plasma experiments

We review experiments performed on cesium and potassium thermal plasmas produced by thermal ionization of neutral atoms on tungsten and tantalum surfaces. A brief description of typical cesium or potassium thermal-plasma devices is given in section 2 of the paper. Section 3 deals with actual experiments, and the material is divided as follows: a. Experiments on plasma diffusion across a magnetic field. In these experiments it is found that when no current is passed through the plasma, diffusion proceeds according to the predictions of the “classical” theory (D⊥ ≈ 1/B2). The magnitudes of the diffusion coefficients are also in agreement with the results of classical theory based on ion-electron collisions. b. Excitation and propagation of low-frequency waves. Three different experiments are described. The first deals with ion waves excited by passage of a small current along the magnetic lines over a very small part of the plasma cross section. The frequency of the oscillations is generally slightly in excess of the ion cyclotron frequency, and the waves are electrostatic ion waves propagating almost at a right angle to the magnetic lines. The second experiment deals with ion waves propagating in the azimuthal direction across the magnetic lines and the radial density gradients of the plasma column. The phase velocity of these waves has the same magnitude as the ion macroscopic velocity of the zero-order motion. The third experiment deals with excitation, propagation along the magnetic lines and damping of ion acoustic waves. The phase velocity and the damping of the waves have been measured. In particular, the wave attenuation appears to be explainable only in terms of collisionless (Landau) damping. c. Spectroscopy experiments. We give a brief description of a spectroscopic determination of the recombination coefficient in cesium. d. Beam-plasma interaction. We discuss the effect of this interaction on the amplification of a microwave signal applied as a modulation to an electron beam that passes through a 2.2-cm length of cesium plasma. Section 4 contains a few considerations about experiments that appear feasible with alkali-metal plasma devices, some of which are under way. In particular, the production of a cesium plasma in a stellarator geometry is considered.
MAPPING THE DIFFUSE ULTRAVIOLET SKY WITH THE GALAXY EVOLUTION EXPLORER

We present a map of the diffuse ultraviolet cosmic background in two wavelength bands (FUV: 1530 Å and NUV: 2310 Å) over almost 75% of the sky using archival data from the Galaxy Evolution Explorer (GALEX) mission. Most of the diffuse flux is due to dust-scattered starlight and follows a cosecant law with slopes of 545 photons cm−2 s−1 sr−1 Å−1 and 433 photons cm−2 s−1 sr−1 Å−1 in the FUV and NUV bands, respectively. There is a strong correlation with the 100 μm Infrared Astronomy Satellite (IRAS) flux with an average UV/IR ratio of 300 photons cm−2 s−1 sr−1 Å−1 (MJy sr−1)−1 in the FUV band and that of 220 photons cm−2 s−1 sr−1 Å−1 (MJy sr−1)−1 in the NUV band but with significant variations over the sky. In addition to the large-scale distribution of the diffuse light, we note a number of individual features including bright spots around the hot stars Spica and Achernar.
An improved approach to power losses in magnetic laminations under nonsinusoidal induction waveform

It is shown that it is possible to accurately predict power losses in ferromagnetic laminations under nonsinusoidal magnetic flux by specifically considering the dependence of hysteresis, classical, and excess loss components (P/sub h/, P/sub c/, and P/sub e/, respectively) on the magnetic induction derivative B. Basically, it is assumed, through generalization of experimental and theoretical results under sinusoidal induction, that P/sub h/ is proportional to the average value of the instantaneous induction derivative, P/sub c/ is proportional to the average value of the square of the instantaneous induction derivative, and P/sub e/ is proportional to the average value of the instantaneous induction derivative to the three-halves power. An analytical expression for total power losses under distorted flux is consequently worked out. Experiments are reported concerning grain-oriented, nonoriented, and amorphous laminations, with distortion introduced by a variable amount of the third harmonic flux component. >