Miracle-dz/UniFAR-FTUs huggingface dataset:
Experimental study of unconfined surface wave discharges at atmospheric pressure by optical emission spectroscopy

A surface wave discharge (SWD) in argon at atmospheric pressure generated by a surfatron device was studied by optical emission spectroscopy (OES). Two distinct situations were investigated; (i) a discharge plasma in open air and (ii) a discharge plasma totally confined in a quartz tube. The electron density ne, electron temperature Te and gas temperature Tg were investigated as a function of applied power and gas flow rate. The self-absorbing method was used to estimate the population of the metastable state Ar(1s5). These physical quantities were determined through optical measurements along the plasma axis of symmetry. The profile of the electron density presented a maximum value under certain conditions, in contrast with typical electron density profiles of SWDs which are usually monotonically decreasing. A correlation between the electron density and the metastable state Ar(1s5) was found in one of these cases, suggesting that stepwise ionization from metastable states and non-local kinetics play an important role on the unexpected increase in ionization degree along the discharge.
Pressure boundary conditions for incompressible flow using unstructured meshes

Abstract This article presents a numerical method for computing incompressible flows with given pressure boundary conditions. Unstructured meshes composed of arbitrary polyhedra are considered in a cell-centered, co-located pressure-velocity formulation. The SIMPLE algorithm of Patankar and Spalding is extended to develop correction equations for boundary static pressure and boundary mass flux through an added-dissipation scheme. The procedure is validated against published benchmarks and shown to perform satisfactorily.
The effect of surface tension on the contraction coefficient of a jet

Two-dimensional free surface potential flow issued from an opening of a container is considered. The flow is assumed to be inviscid and incompressible. The mathematical problem, which is characterized by the nonlinear boundary condition on the free surface of an unknown equation, is solved via a series truncation. We computed solutions for all Weber numbers. Our problem is an extension of the work done by Ackerberg and Liu (1987 Phys. Fluids 30 289–96), the results confirm and extend their results.
A generalized inspection game

The paper addresses the problem of a patrol trying to stop smugglers who are attempting to ship a cargo of perishable contraband across a strait in one of M time units. The situation was modeled as a two-person zero-sum game of exhaustion by Thomas and Nisgav and this article extends their results. The game has many characteristics in common with the Inspection Game in Owen's book on Game Theory; this Inspection Game is generalized and the relations between the two games are discussed.
Nonlinear evolution equation for the stress-driven morphological instability

A flat surface of stressed solid is unstable to small perturbations. This morphological instability is called Asaro–Tiller–Grinfield instability. Nonlinear evolution of this instability will result in the formation of cusp singularities. This instability can be described by a continuum model with surface diffusion driven by a stress-dependent chemical potential. The stress and strain in the solid are coupled with surface morphology and an elasticity problem must be solved numerically. We derive a nonlinear approximation equation governing the evolution of this instability in which the stress-dependent chemical potential is expressed explicitly as a function of the surface morphology. Linear instability analysis using our equation shows the same results as the well-known Asaro–Tiller–Grinfeld instability result. Compared with the exact solution of the elasticity problem for cycloid surface obtained by Chiu and Gao, our nonlinear approximation has a much wider range of applicability than linear approximatio.
The effect of school resources on pupil attainment: a multilevel simultaneous equation modelling approach

Summary. Improving educational achievement in UK schools is a priority, and of particular concern is the low achievement of specific groups, such as those from lower socio‐economic backgrounds. An obvious question is whether we should be improving the outcomes of these pupils by spending more on their education. The literature on the effect of educational spending on the achievement of pupils has some methodological difficulties, in particular the endogeneity of school resource levels, and the intraschool correlations in pupils’ responses. We adopt a multi‐level simultaneous equation modelling approach to assess the effect of school resources on pupil attainment at age 14 years. The paper is the first to apply a simultaneous equation model to estimate the effect of school resources on pupils’ achievement, using the newly available national pupil database and pupil level annual school census.
Mental Imagery Scale: a new measurement tool to assess structural features of mental representations

Mental imagery is a quasi-perceptual experience which resembles perceptual experience, but occurring without (appropriate) external stimuli. It is a form of mental representation and is often considered centrally involved in visuo-spatial reasoning and inventive and creative thought. Although imagery ability is assumed to be functionally independent of verbal systems, it is still considered to interact with verbal representations, enabling objects to be named and names to evoke images. In literature, most measurement tools for evaluating imagery capacity are self-report instruments focusing on differences in individuals. In the present work, we applied a Mental Imagery Scale (MIS) to mental images derived from verbal descriptions in order to assess the structural features of such mental representations. This is a key theme for those disciplines which need to turn objects and representations into words and vice versa, such as art or architectural didactics. To this aim, an MIS questionnaire was administered to 262 participants. The questionnaire, originally consisting of a 33-item 5-step Likert scale, was reduced to 28 items covering six areas: (1) Image Formation Speed, (2) Permanence/Stability, (3) Dimensions, (4) Level of Detail/Grain, (5) Distance and (6) Depth of Field or Perspective. Factor analysis confirmed our six-factor hypothesis underlying the 28 items.
Sign-Solvable Cone-Systems

Qualitative properties shared by the solutions to the family of linear equations of the form $$Ax=b, \quad (A\in C, b \in B),\eqno(1)$$ where C is a cone in ${\shadR}^{m\times n}$ and B is a cone in ${\shadR}^m$ are studied. In particular, the cones C and B for which the sign patterns of the solutions to (1) are independent of the choice of A ε C and b ε B are characterized.
2D properties of core turbulence on DIII-D and comparison to gyrokinetic simulations

Quantitative 2D characteristics of localized density fluctuations are presented over the range of 0.3<r/a<0.9 in L-mode plasmas on DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)]. Broadband density fluctuations increase in amplitude from n/n<0.5% in the deep core to n/n∼2.5% near the outer region. The observed Doppler-shift due to the E×B velocity matches well with the measured turbulence group and phase velocities (in toroidally rotating neutral beam heated plasmas). Turbulence decorrelation rates are found to be ∼200 kHz at the edge and to decrease toward the core (0.45<r/a<0.9) where they approach the E×B shearing rate (∼50 kHz). Radial and poloidal correlation lengths are found to scale with the ion gyroradius and exhibit an asymmetric poloidally elongated eddy structure. The ensemble-averaged turbulent eddy structure changes its tilt with respect to the radial-poloidal coordinates in the core, consistent with an E×B shear mechanism. The 2D spatial correlation and wavenumber spectra [S(kr,kθ)] are.
CW to QCW power scaling of high-power laser bars

We report on laser diode bars with wavelengths ranging from 793 to 1080 nm and optimized for high power and high temperature operation. For 808 nm bars output power values of 300 W at 300 A drive current and 200 μs pulse length have been recorded at a cooler temperature of 75°C. Extending our wavelength range to 1080nm we report on bars with >65% power conversion efficiency in CW operation and more than 500 W output power for a wide range of qCW modes. Finally, the properties of a 6-bar stack with 3 kW output power at 460 A drive current and 200 μs pulse width will be discussed.
Optimal reactive dispatch through interior point methods

An implementation of an interior point method to the optimal reactive dispatch problem is described. The interior point method used is based on the primal-dual algorithm and the numerical results in large scale networks (1832 and 3467 bus systems) have shown that this technique can be very effective to some optimal power flow applications. >
Measurements of calf liver ultrasonic differential and total scattering cross sections

Ultrasonic scattering from calf liver has been measured and normalized to obtain the average differential scattering cross section per unit volume σsd (ν) over scattering angles ν ranging in magnitude from 25 ° to 165 ° and frequencies between 3 and 7 MHz. The results indicate that, at each of the measured frequencies, calf liver is a weak scatterer with nearly one‐half of the total scattered power directed between 25 ° and 45 °. The value of σsd (165 °) , which is not expected to differ much from σsd (180 °) , the backscattering coefficient, was found to be approximately 3.7 × 10−6f1.4 mm−1Ω−1, with f in MHz and Ω in steradians. By integrating σsd over all the measured scattering angles to find the total scattering cross section σst , the contribution of scattering loss to attenuation was found to be approximately 2% over the measured frequencies. Analysis of the shape of σsd suggests that the correlation length of the liver was on the order of 1 mm. To assess the accuracy of the normalization meth.
Cohesion Versus Structural Equivalence as a Basis for Network Subgroups

Two basic approaches to network analysis are compared in terms of the network subgroups each produces. The relational approach, developing from traditional sociometry, focuses on relations between actors (individuals, groups, or corporations) and aggregates actors connected by cohesive bonds into "cliques. " The positional approach focuses on the pattern of relations in which an actor is involved and aggregates actors with similar patterns, i.e., "structurally equivalent" actors, into jointly occupied positions. There are several questions that can be posed for a specific project that might lead an individual to analyze subgroups in terms of cohesion versus structural equivalence. Here, considering a series of such questions, I conclude that subgroups based on structural equivalence are to be preferred to those based on cohesion. Cliques can be analyzed as a special type of jointly occupied network position. Illustration is provided by data on the elite experts in methodological and mathematical sociology circa 1975.
Rotational friction of single-wall carbon nanotubes in liquid suspension

The hydrodynamics of single-wall carbon nanotubes rotated in liquid suspension by an external electric field was experimentally investigated with laser polarimetry and compared with theoretical predictions. The measured rates of change of the nematic order parameter were largely consistent with theoretical predictions based on classical, no-slip hydrodynamics. This implies that, despite the nanotubes’ diameter approaching the size of the solvent molecules and the reduced resistance previously reported for internal flow through carbon nanotubes, classical continuum hydrodynamics holds approximately for external flow about individual single-wall carbon nanotubes in liquids.
High-resolution X-ray spectroscopic evidence of nonequilibrium conditions in the Cygnus Loop

High-resolution spectroscopic X-ray observations of a portion of the Cygnus Loop made with the Focal Plane Crystal Spectrometer aboard the Einstein Observatory are reported. Emission lines for O VII, O VIII, and Ne IX are measured, and upper limits are set to other transitions in O VII and O VIII. The detected emission line fluxes are consistent with emission from an equilibrium plasma with an electron temperature of about 3 x 10 to the 6th K, a value similar to that obtained by numerous previous observers. The absence of any O VII forbidden line emission strongly suggests that the emitting plasma is not in collisional ionization equilibrium. This is shown to be the case using several line diagnostics formed from the observed emission lines and a simple model describing the X-ray emission from an ionizing nonequilibrium plasma.
System identification using Laguerre models

The traditional approach of expanding transfer functions and noise models in the delay operator to obtain linear-in-the-parameters predictor models leads to approximations of very high order in cases of rapid sampling and/or dispersion in time constants. By using prior information about the time constants of the system more appropriate expansions, related to Laguerre networks, are introduced and analyzed. It is shown that the model order can be reduced, compared to ARX (FIR, AR) modeling, by using Laguerre models. Furthermore, the numerical accuracy of the corresponding linear regression estimation problem is improved by a suitable choice of the Laguerre parameter. Consistency (error bounds), persistence of excitation conditions. and asymptotic statistical properties are investigated. This analysis is based on the result that the covariance matrix of the regression vector of a Laguerre model has a Toeplitz structure. >
Development and performance test of the analysis software for the CRIB active target

Software for genuinely event-by-event analysis and event reconstruction of data obtained by using an active target has been developed in the graphical user interface under the CERN ROOT framework. The primary motivation for developing the software was to provide physicists who perform experiments using an active target a more user-friendly environment for the purpose of investigating the performance of detection systems and obtaining ideas about physics from a large amount of experimental data. To test the performance of the software, we analyzed experimental data from a 16N radioactive ion beam experiment for α-decay measurements. As a result of the analysis, we observed the Bragg curve and measured the range of the 16N RI beam in the detector. Data were calibrated against the calculation after comparing the Bragg curve to the one obtained from an energy loss calculation in P-10 gas. We present a detailed description of the analysis software and its test results.
Kinetics of coupled map lattices

A simple example of coupled map lattices generated by expanding maps of the unit interval with some kind of diffusion coupling is considered. It has been stated that this system has an unique invariant mixing measure with absolutely continuous finite-dimensional projections. Here the author proves that probability measures from some natural class weakly converge to this measure under the actions of dynamics. The main idea of the proof is the symbolic representation of his system by two-dimensional lattice model of statistical mechanics. It provides the possibility of applying results from random field theory.
THE SOLUTION OF LINEAR DIFFERENCE MODELS UNDER RATIONAL EXPECTATIONS

IN HIS SURVEY ON RATIONAL EXPECTATIONS, R. Shiller indicates that the difficulty of obtaining explicit solutions for linear difference models under rational expectations may have hindered their use [14, p. 27]. The present paper attempts to remedy that problem by giving the explicit solution for an important subclass of the model Shiller refers to as the general linear difference model. Section 1 presents the form of the model for which the solution is derived and shows how particular models can be put in this form. Section 2 gives the solution together with the conditions for existence and uniqueness. 1. THE MODEL The model is given by (la), (lb), and (1c) as follows:
Numerical simulation of thermomechanical behaviours of shape memory alloys via a non‐linear mesh‐free Galerkin formulation

A new computational approach is developed based on the mesh‐free method for the numerical simulation of shape memory alloys. A thermomechanical constitutive model is used to describe the complex material response. The incremental displacement‐based mesh‐free formulation is constructed in a total Lagrangian description by employing the moving least square shape function and rate form of the shape memory alloy constitutive model in the variational equations. This mesh‐free formulation is not only applicable to large deformation problems, but also accounts for both stress and thermally induced phase transformation. Moreover, the newly developed mesh‐free codes can deal with complex loading paths and multiple temperature cycles in numerical simulation. The performance of the proposed mesh‐free scheme for the simulation of shape memory alloys is demonstrated in several numerical examples. Copyright © 2005 John Wiley & Sons, Ltd.
AXIAL FATIGUE OF MULTILAYERED STRANDS

Previously reported orthotropic sheet theory is used for obtaining estimates of interwire/interlayer contact stresses throughout realistic pretensioned multilayered structural strands. These data are used in conjunction with axial fatigue data on single wires to develop a theoretical model that predicts axial fatigue life of strands (under constant amplitude cyclic loading) from first principles. The theoretical interlayer slippage over the individual points of contact between cross-laid layers is addressed, which takes interwire friction into account. The match between the theoretical predictions and experimental fatigue data is very encouraging. Numerical examples suggest that cable axial fatigue life depends on the type of strand construction. The level of mean axial load appears to have a modest effect on the cable stress range versus fatigue life (S-N) curves. For a given wire material, the endurance limit is found to increase with increasing level of mean axial load, becoming practically constant for mean axial loads greater than 40% of the cable maximum breaking load. Different types of cable construction are found to possess significantly different levels of endurance limit.
Solving a stochastic facility location/fleet management problem with logic-based Benders' decomposition

This article addresses a stochastic facility location and vehicle assignment problem in which customers are served by full return trips. The problem consists of simultaneously locating a set of facilities, determining the vehicle fleet size at each facility, and allocating customers to facilities and vehicles in the presence of random travel times. Such travel times can arise, for example, due to daily traffic patterns or weather-related disturbances. These various travel time conditions are considered as different scenarios with known probabilities. A stochastic programming with bounded penalties model is presented for the problem. In order to solve the problem, integer programming and two-level and three-level logic-based Benders’ decomposition models are proposed. Computational experiments demonstrate that the Benders’ models were able to substantially outperform the integer programming model in terms of both finding and verifying the optimal solution.
Relative Cross Sections for Electron‐Impact Dissociation of SF6 into SFx (x = 1−3) Neutral Radicals

The energy dependence of the partial cross sections of electron-impact dissociation of SF 6 into the neutral radicals SF, SF 2 and SF 3 is measured from the threshold to 200 eV. This measurement is accomplished by appearance mass spectrometry in a dual electron beam device. The dissociation products SF 4 and SF 5 are below the detection limit of the present system. The threshold energies for neutral dissociation into SF 3 , SF 2 and SF are measured to be 16.0, 19.5 and 22.0 eV respectively. The surface loss probability of each radical and the electron-impact nitrogen dissociation are examined to evaluate the relative dissociation cross section. However, the absolute cross section cannot be assigned for lack of the ionization cross sections for the SF x radicals.
HELICON-WAVE PROPAGATION IN A LABORATORY PLASMA.

Measurements have been made of the propagation of axially symmetric helicon waves in the afterglow of a pulsed plasma. The experimental values for the dispersion relation approach the theoretical values calculated for a cylindrical plasma column with zero under Bessel function radial density distribution, after time intervals several times longer than the radial diffusion time.
Classical Noise. V. Noise in Self-Sustained Oscillators

A spectrally pure self-sustained oscillator, described by a positive- and negative-impedance series circuit $Z={Z}_{n}+{Z}_{p}$ such that $Z{e}^{i\ensuremath{\omega}t}={e}^{i\ensuremath{\omega}t}Z(\ensuremath{\omega}, D)$, yields a single frequency output depending nonlinearly on a parameter $D$ related to an instantaneous or recent-time-averaged power. The oscillator operates at a point $D={D}_{0}$ at which gains and losses cancel, ${R}_{p}+{R}_{n}\ensuremath{\equiv}R({\ensuremath{\omega}}_{0}, {D}_{0})=0$, and at a frequency ${\ensuremath{\omega}}_{0}$ determined by ${X}_{p}+{X}_{n}\ensuremath{\equiv}X({\ensuremath{\omega}}_{0}, {D}_{0})=0$. Since $R=0$, the oscillator linewidth vanishes in the absence of noise. We endow the resistances ${R}_{p}$ and ${R}_{n}$ with Langevin noise sources. Amplitude fluctuations produce a broad additive background. The oscillator is unstable against phase fluctuations, which broaden the signal into finite width. A quasilinear treatment, well above threshold, demonstrates that the phase executes a Brownian motion. If $\frac{\ensuremath{\partial}R}{\ensuremath{\partial}\ensuremath{\omega}}\ensuremath{\ne}0$ or $\frac{\ensuremath{\partial}X}{\ensuremath{\partial}D}\ensuremath{\ne}0$ at the operating point, phase and amplitude fluctuations are coupled. Nevertheless, we succeed in calculating the linewidth and proving that it is independent of the rate at which power (or $D$) relaxes. A comparison is made with the "linear" treatment of oscillators as amplified noise. A reduced random process is set up, valid for time intervals obeying ${\ensuremath{\omega}}_{0}\ensuremath{\Delta}t\ensuremath{\gg}1$. Although the phase of the oscillator involves a nonlinear, nonstationary action on the Gaussian input noise, it is shown that well above threshold, for the reduced process, the phase is again properly described as a Gaussian variable subject to the expected Brownian-motion diffusion. For all well-designed oscillators, even near threshold, we establish that the reduced random process is that of a rotating-wave van der Pol oscillator. A comparison is made between quasilinear solutions of the rotating-wave van der Pol oscillator and exact solutions of the Fokker-Planck equation computed in the next paper, VI, in this series. For intensity fluctuations it is demonstrated that quasilinear methods are quantitatively valid away from the threshold region and qualitatively valid near threshold, provided that the quasilinear approximation is made in the correct variable.