Miracle-dz/UniFAR-FTUs huggingface dataset:
Impact of Satellite Observations on the Tropical Cyclone Track Forecasts of the Navy Operational Global Atmospheric Prediction System

Abstract The tropical cyclone (TC) track forecasts of the Navy Operational Global Atmospheric Prediction System (NOGAPS) were evaluated for a number of data assimilation experiments conducted using observational data from two periods: 4 July–31 October 2005 and 1 August–30 September 2006. The experiments were designed to illustrate the impact of different types of satellite observations on the NOGAPS TC track forecasts. The satellite observations assimilated in these experiments consisted of feature-track winds from geostationary and polar-orbiting satellites, Special Sensor Microwave Imager (SSM/I) total column precipitable water and wind speeds, Advanced Microwave Sounding Unit-A (AMSU-A) radiances, and Quick Scatterometer (QuikSCAT) and European Remote Sensing Satellite-2 (ERS-2) scatterometer winds. There were some differences between the results from basin to basin and from year to year, but the combined results for the 2005 and 2006 test periods for the North Pacific and Atlantic Ocean basins indica.
Ignition and instability of low-current DC vacuum arcs ignited by the opening of the electrodes

The ignition, lifetime, and instability of low-current DC vacuum arcs, which were ignited by the opening of the electrodes, were investigated experimentally. Copper electrodes were used and the arc current was less than 50 A. Waveforms of the voltage and current between the electrodes at the moment of arc ignition and during the arc continuation were measured. It was confirmed that, for the ignition of the arc, a voltage which was larger than a critical value should appear between the electrodes at the moment of the opening of the electrodes. The lifetime of the arc is short, less than 1 s in the present condition, and increases with an increase in arc current and output voltage of the current source. The arc voltage consists of a certain DC level, around 20 V, and an additive high-frequency component. The arc current consists of a certain DC level and a subtractive high-frequency component.
Triggered discharges with high arc voltages in a vacuum interrupter

Studies of nonsustained disruptive discharges (NSDDs), isolated cases of which can occur in vacuum interrupters, indicate lateral discharges between the cathode and shield, which can initiate a brief discharge between the contacts. To facilitate the study of such discharges, the sample discharges were triggered by a surface discharge induced by a spark gap, built into the side of the cathode, and observed with a high-speed film camera and image-converter camera. The tests showed a cathode spot after igniting. The emitted electrons first charge the shield negatively and then are directed toward the anode. The discharge burns at a high voltage, with current ranging from 10 to 100 A. After a period of up to 400 mu s, the current demand increases abruptly; an arc discharge occurs between the contacts and discharges the capacitances near the switch. The contact gap undergoes a rapid dielectric recovery, and the restored voltage is maintained. These types of discharge were also observed with NSDDs; thus it can be assumed that the triggered discharges studied correspond to the NSDD type. >
Electron acceleration in relativistic GRB shocks

The shock model of gamma-ray bursts (GRBs) has two free parameters: εB and εe. It has been shown that εB should range between few×10−3 and few×10−4. However, how to calculate the value of εe has remained an outstanding theoretical problem for over a decade. Here, we demonstrate that the Weibel theory inevitably predicts that . The GRB afterglow data fully agree with this theoretical prediction. Our result explains why the electrons are close to equipartition in GRBs. This εe–εB relation can potentially be used to reduce the number of free parameters in afterglow models.
The motion of a shock wave in a channel, with applications to cylindrical and spherical shock waves

A first-order relationship between changes in area and shock strength is derived for the case of a shock moving through a small area change in a channel. By integration of this relationship the area of the channel is obtained as a function of the shock strength in closed form. This result is interpreted as giving the average strength of a shock at a given time as it moves along a channel of arbitrary shape. By suitable choices of the shape of the channel, descriptions of converging cylindrical and spherical shocks are obtained. These descriptions are found to be in close agreement with the similarity solutions valid near the points of collapse of the shocks. The reason for such good agreement is examined.
On the parabolic equation method for water-wave propagation

A parabolic approximation to the reduced wave equation is investigated for the propagation of periodic surface waves in shoaling water. The approximation is derived from splitting the wave field into transmitted and reflected components. In the case of an area with straight and parallel bottom contour lines, the asymptotic form of the solution for high frequencies is compared with the geometrical optics approximation. Two numerical solution techniques are applied to the propagation of an incident plane wave over a circular shoal.
Some lotto numbers from an extension of turan's theorem

Turan's theorem implies that the minimum possible number of edges of a graph G on 2m points with maximum stable set of size two is m(m-1), and that this minimum is attained only when G is the union of two m-cliques. Here we show that when G has no more than m2-2 edges still the conclusion holds that G is the union of two cliques (butnotnecessarily of equal size). As a corol lary the lotto numbers L(n,3,3,2) are determined. (I.e., the minimum number of lotto forms of size three on has to complete in order to be sure of two correct answers when three numbers are drawn.)
Generation of coherent phonons in condensed media

The generation of coherent phonons by absorption of femtosecond laser pulses through interband transitions in different materials is summarized. Starting with layered III-VI semiconductors, where optical excitation is performed with amplified pulses, the generation mechanism via strong interband transitions is investigated. In Ge, stimulated resonant Raman scattering is found to be the decisive driving force. In GaAs, however, the ultrafast screening of surface space charge fields launches LO-phonons via electrostatic coupling. In the metallic state of high-temperature superconductors, the generation of highly symmetric A/sub g/ modes is assigned to displacive processes induced by a nonequilibrium electronic carrier distribution. In the superconducting state the amount of coherent displacement is strictly correlated to the number of optically broken superconducting pairs. In addition to the comparison of various generation processes, the dephasing of coherent phonons is addressed. >
Stochastic analysis of nonstationary subsurface solute transport: 1. Unconditional moments

This paper applies stochastic methods to the analysis and prediction of solute transport in heterogeneous saturated porous media. Partial differential equations for three unconditional ensemble moments (the concentration mean, concentration covariance, and velocity concentration cross covariance) are derived by applying perturbation techniques to the governing transport equation for a conservative solute. Concentration uncertainty is assumed to be the result of unmodeled small-scale fluctuations in a steady state velocity field. The moment expressions, which describe how each moment evolves over time and space, resemble the classic deterministic advection-dispersion equation and can be solved using similar methods. A solution procedure based on a Galerkin finite element algorithm is illustrated with a hypothetical two-dimensional example. For this example the required steady state velocity statistics are obtained from an infinite domain spectral solution of the stochastic groundwater flow equation. The perturbation solution is shown to reproduce the statistics obtained from a Monte Carlo simulation quite well for a natural log conductivity standard deviation of 0.5 and moderately well for a natural log conductivity standard deviation of 1.0. The computational effort required for a perturbation solution is significantly less than that required for a Monte Carlo solution of acceptable accuracy. Sensitivity analyses conducted with the perturbation approach provide qualitative confirmation of a number of results obtained by other investigators for more restrictive special cases.
A Comparison of Item Selection Rules at the Early Stages of Computerized Adaptive Testing

The effects of five item selection rules—Fisher information (FI), Fisher interval information (FII), Fisher information with a posterior distribution (FIP), Kullback-Leibler information (KL), and Kullback-Leibler information with a posterior distribution (KLP)—were compared with respect to the efficiency and precision of trait (Θ) estimation at the early stages of computerized adaptive testing (CAT). FII, FIP, KL, and KLP performed marginally better than FI at the early stages of CAT for Θ= -3 and -2. For tests longer than 10 items,there appeared to be no precision advantage for any of the selection rules.
Effects of the stimulus spectrum on temporal weighting of binaural differences

The influence, or "perceptual weight" of binaural information typically varies over the duration of a brief sound, as characterized by the temporal weighting function (TWF). Here, TWFs were measured for binaural lateralization of Gabor click trains (GCT) varying in carrier frequency from 1 to 8 kHz, and of broadband noise-burst trains (NBT) with repeated ("frozen") or newly-sampled ("fresh") noise across bursts. Interclick intervals (ICI) ranged 2-10 ms. On each of many trials, listeners judged the lateral position of a singly presented GCT or NBT. Lateral positions varied with the overall interaural time (ITD, ranging +/- 500 µs) and level (ILD, ranging +/-5 dB) differences applied to each stimulus. Additional random variation in ITD (+/- 100 µs) and ILD (+/- 2dB) was applied independently to each click within a train. TWFs were calculated by multiple linear regression of normalized position judgments onto the individual click ITD and ILD values, and indicated large ICI-dependent weights on the initial click, elevated weights near offset, and lower weights for interior clicks. Flatter TWFs were observed for "fresh" NBT stimuli than for GCT or "frozen" NBT stimuli. Results corroborate previous reports of temporal asymmetries in binaural processing of periodic stimuli across frequency. [Supported by R01 DC011548]
Uniform Limit Theory for Stationary Autoregression

Abstract. First order autoregression is shown to satisfy a limit theory which is uniform over stationary values of the autoregressive coefficient ρ = ρn ∈ [0, 1) provided (1 − ρn)n → ∞. This extends existing Gaussian limit theory by allowing for values of stationary ρ that include neighbourhoods of unity provided they are wider than O(n−1), even by a slowly varying factor. Rates of convergence depend on ρ and are at least but less than n. Only second moments are assumed, as in the case of stationary autoregression with fixed ρ.
Experimental study of three shock wave/turbulent boundary layer interactions

Experiments were performed to investigate the supersonic flow of a turbulent boundary layer over a number of compression-corner models. Upstream of each corner, the free-stream Mach number was 2.9 and the incoming boundary layer was typical of a two-dimensional, zero-pressure-gradient, high-Reynolds-number flow. Three different corner angles were used, namely 8°, 16° and 20°, and at the highest angle the interaction was strong enough to cause separation. Each flow was investigated using normal and inclined hot wires, and measurements of the longitudinal mass-flux fluctuations and the mass-weighted turbulent shear stress are presented. The behaviour of the kinematic and Reynolds stresses, deduced from the mass-weighted quantities by applying Morkovin's ‘strong Reynolds analogy’, is also considered. In all three flow cases, the interaction dramatically amplifies the turbulent stresses, and the amplification increases with increasing turning angle. Different stress components are amplified by different amounts, however, and the structure parameter $-\overline{u^{\prime}v^{\prime}}/\overline{u^{\prime 2}}$ changes significantly through the interaction. Perhaps more importantly, the nature of these changes depends on the strength of the interaction. This result is rather unexpected, and it is believed to be due mainly to the unsteadiness of the shock system. It is suggested that the apparently random motion of the shock system affects the normal stresses more than the shearing stresses, and, since the unsteadiness increases with corner angle, the effect on the turbulence structure also becomes more pronounced.
Analysis of Interacting Nucleic Acids in Dilute Solutions

Motivated by the growing demand for analysis tools for diverse natural and engineered DNA and RNA systems, we develop a general theory and set of computational algorithms to perform thermodynamic analysis of dilute reactive solutions and then apply these techniques to interacting nucleic acids. The theory correctly accounts for the effects of indistinguishability in partition function calculations for complexes of interacting strands. With partition functions in hand, the unique complex concentrations corresponding to thermodynamic equilibrium are obtained by solving a convex programming problem. Partition function and concentration information can then be used to calculate equilibrium base-pairing observables corresponding to experimentally measurable properties. The underlying physics and mathematical formulation of these problems lead to an interesting blend of approaches, including ideas from graph theory, group theory, dynamic programming, combinatorics, convex optimization, and Lagrange duality. To make these analysis tools available to researchers worldwide, we present NUPACK, a web-based software suite for thermodynamic analysis of nucleic acids. Its efficacy is demonstrated in example calculations and the results are shown to be in agreement with experiment. Finally, the thermodynamic properties of a DNA-based triggered self-assembly device [1] are analyzed using NUPACK and extensions of its tools. The computational results complement experimental studies, exposing novel properties about the system and dictating further research.
Analysis of a Strip Monopole Mounted Near an Edge or a Vertex

The strip monopole model is used in the problem of a wire attached to an arbitrary conducting surface segmented with triangular patches. Some segmentation methods for the patches are described for the problem when the junction is near an edge or a vertex. Only a few triangular patches on the surface are segmented to get more equilateral triangles when the strip monopole is added on the surface. The advantages of applying these segmentation methods are illustrated with several representative examples, which show good versatility and efficiency for solving the problems of wire/surface junctions.
Adaptive Computational Methods for Parabolic Problems

We present a unied methodology for the computational solution of parabolic systems of differential equations with adaptive selection of discretization in space and time, based on a posteriori error estimates involving residuals of computed solutions and stability factors/weights, obtained by solving an associated linearized dual problem. We dene parabolicity as boundedness in time (up to logarithmic factors) of a certain strong stability factor measuring the -norm in timenspace of the time derivative of the dual solution with -normalized initial data.
Boundary layers of the incompressible fluids for a permeable wall

In this article, the aim is to study the incompressible Navier‐Stokes equations with a permeable wall and derive the complete asymptotic expansion with respect to the kinematic viscosity ν. More precisely, we derive the physically uniform (in time and space) estimates of the boundary layers and prove that the asymptotic expansion is reasonable in uniform norm. This improves the results already obtained by R. Temam and X. Wang (2000, ZAMM, Volume 80 Issue 11–12, Pages 835–843).
CHANGE-OVER DESIGNS WITH ERRORS FOLLOWING A FIRST ORDER AUTOREGRESSIVE PROCESS

Summary This paper deals with the problem of analysing the change over design in the context of a first order autoregressive process for the error terms. The method of maximum likelihood has been adopted for estimating treatment effects. The conditions derived for obtaining a balanced change over design show that a change over design balanced in the absence of autocorrelation is not necessarily balanced in the presence of autocorrelation. Also, it is observed that the autocorrelation co-efficient and the treatment effect when p≠0 can be tested as usual with the likelihood ratio test criterion.
Temperature Compensation of a Fiber Optic Strain Sensor Based on Brillouin Scattering

Brillouin scattering-based fiber optic sensors are useful to measure strain or temperature in a distributed manner. Since the Brillouin frequency of an optical fiber depends on both the strain and temperature, it is very important to know whether the Brillouin frequency shift is caused by the strain change or temperature change. This article presents a temperature compensation technique of a Brillouin scattering-based fiber optic strain sensor. Both the changes of the Brillouin frequency and the Brillouin gain power is observed for the temperature compensation using a BOTDA sensor system. Experimental results showed that the temperature compensated strain values were highly consistent with actual strain values.
A study of two-dimensional flow past regular polygons via conformal mapping

In this paper we study two-dimensional flow around regular polygons with an arbitrary but even number of edges N and one apex pointing to the free stream, with comparison to circular-cylinder flow. Both inviscid flow and low-Reynolds-number viscous flow are addressed. For inviscid flow, we obtained the exact solution for pure potential flow through Schwarz–Christoffel transformation, with the emphasis on the role of edge number, N, on the flow details. We also studied the behaviour, stationary lines and stability of vortex pair and found new stationary lines compared to circular cylinder. For viscous flow we derived the equation of stream function in the mapped (circle) domain, based on which approximate expressions for the critical Reynolds numbers and Strouhal number, as functions of the edge number, are obtained. The Reynolds number is based on the diameter of the circumscribed circle. For the steady flow, the first critical Reynolds number is a monotonically decreasing function of N, while N → ∞ corresponds to that for circular cylinder. The bifurcation point is ahead of the bifurcation point for circular cylinder. For unsteady flow, the critical Reynolds number for vortex shedding and the Strouhal number are both monotonically decreasing functions of N.
THERMOPIEZOELECTRIC ANALYSIS OF A FUNCTIONALLY GRADED PIEZOELECTRIC MEDIUM

The thermopiezoelectrical behavior of a functionally graded piezoelectric medium (FGPM) is investigated in the present work. For the special case, the dynamic response of an FGPM rod excited by a moving heat source is studied. The material properties of the FGPM rod are assumed to vary exponentially through the length, except for specific heat and thermal relaxation time which are held constant for simplicity. The governing differential equations in terms of displacement, temperature, and electric potential are obtained in a general form that includes coupled and uncoupled thermoelasticity. The coupled formulation considers classical thermoelasticity as well as generalized thermoelasticity. Employing the Laplace transform and successive decoupling method, unknowns are given in the Laplace domain. Employing a numerical Laplace inversion method, the solutions are gained in the time domain. Numerical examples for the transient response of the FGPM rod are displayed to clarify the differences among the result.
On Variational Principles and Matrix Methods in Elastodynamics

Sirrnmary The equations of elastodynamics are conveniently derived from a variational principle and by considering an averaged Lagrangian for a harmonic field in a stratified elastic medium it is possible to obtain a set of coupled first order differential equations as the Hamilton’s canonical equations. These equations are precisely those which form the basis of the matrix methods commonly used for handling elastic wave propagation in layered media. The variational results are extended to deal with the more complicated ‘h4inor Matrix’ system of Gilbert & Backus which improves the numerical accuracy of the computations. The equivalent of Rayleigh’s principle is derived for this system and used to consider the effects of perturbations on surface wave dispersion.
The ring of reciprocal polynomials and rank varieties

Let p be a prime and let G be a finite p‐group. In a recent paper we introduced a commutative graded ℤ‐algebra RG (which classifies the so‐called convolutions on G). Now let K be an algebraically closed field of characteristic p and let M be a non‐zero finitely generated K[G]‐module. A general rank variety WG(M) is constructed quite explicitly as a determinantal subvariety of the variety of K‐valued points of the spectrum of RG. Further, it is shown that the quotient variety WG(M)/G is inseparably isogenous to the usual cohomological support variety VG(M).
Efficiency measurement using a motor–dynamo module

In this article, we describe a simple method which can be used to measure the efficiency of a low power dc motor, a motor-converted dynamo and a coupled motor–dynamo module as a function of the speed of rotation. The result can also be used to verify Faraday’s law of electromagnetic induction.
WARM OCCLUSIONS, COLD OCCLUSIONS, AND FORWARD-TILTING COLD FRONTS

The classical definitions of warm and cold occlusions are updated in light of recent observations and numerical modeling of occluded fronts within midlatitude cyclones. Mesoscale model simulations of occluded fronts show that they are first-order discontinuities in potential temperature, with broad zones of fairly uniform horizontal potential temperature gradient and static stability on either side of the frontal surface. Under this assumption, an analysis of the relationship between the slope of an occluded front and the potential temperature distribution on either side of it yields a “static stability rule,” namely, that an occluded front slopes over the statically more stable air, not the colder air. The static stability rule leads to modifications of the classical definitions of warm and cold occlusions, in which the term “colder air” is replaced by “statically more stable air. ” Examples are given of occluded fronts in which this distinction is important, and the static stability rule is used to exami.