Miracle-dz/UniFAR-FTUs huggingface dataset:
Coronal heating by magnetic reconnection in loops with zero net current

Context. The paper is concerned with heating of the solar corona by nanoflares: a superposition of small transient events in which stored magnetic energy is dissipated by magnetic reconnection. It is proposed that heating occurs in the nonlinear phase of an ideal kink instability, where magnetic reconnection leads to relaxation to a state of minimum magnetic energy. Aims. The aim is to investigate the nonlinear aspects of magnetic relaxation on a current loop with zero net axial current. The dynamical processes leading to the establishment of a relaxed state are explored. The efficiency of loop heating is investigated. Methods. A 3D magnetohydrodynamic numerical code is used to simulate the evolution of coronal loops which are initially in ideally unstable equilibrium. The initial states have zero net current. The results are interpreted by comparison both with linear stability analysis and with helicity-conserving relaxation theory. Results. The disturbance due to the unstable mode is strongly radially confined when the loop carries zero net current. Strong current sheets are still formed in the nonlinear phase with dissipation of magnetic energy by fast reconnection. The nonlinear development consists first of reconnection in a large scale current sheet, which forms near the quasi-resonant surface of the equilibrium field. Subsequently, the current sheet extends and then fragments, leading to multiple reconnections and effective relaxation to a constant α field. Conclusions. Magnetic reconnection is triggered in the nonlinear phase of kink instability in loops with zero net current. Initially, reconnection occurs in a single current sheet, which then fragments into multiple reconnection sites, allowing almost full relaxation to the minimum energy state. The loop is heated to high temperatures throughout its volume.
Pressure-induced structural transition and thermodynamic properties of NbN and effect of metallic bonding on its hardness

Using first-principles calculations, the elastic constants, thermodynamic properties and structural phase transition of NbN under high pressure are investigated by means of the pseudopotential plane-waves method, in addition to the effect of metallic bonding on its hardness. Three candidate structures are chosen to investigate NbN, namely, rocksalt (NaCl), NiAs and WC types. On the basis of the third-order Birch-Murnaghan equation of states, the transition pressure Pt (Pt=200.64 GPa) between the WC phase and the NaCl phase of NbN is predicted for the first time. Elastic constants, formation enthalpies, shear modulus, Young's modulus, and Poisson's ratio of NbN are derived. The calculated results are found to be in good agreement with the available experimental data and theoretical values. According to the quasi-harmonic Debye model, the Debye temperature under high pressure is derived from the average sound velocity. Moreover, the effect of metallic bonding on the hardness of NbN is investigated and the hardness shows a gradual decrease rather than increase under compression. This is a quantitative investigation on the structural and thermodynamic properties of NbN, and it still awaits experimental confirmation.
Standardless Analysis - Better but Still Risky

Today, many vendors have replaced “first principles” standardless analysis with standardless analysis based on “remote standards. ” Rather than relying on pure physics modeling, “remote standards” rely on standards collected on a canonical detector that are then adapted to match the performance characteristics of the detector in your laboratory. Rather than having to normalize every result to 100 % to compensate for poor knowledge of certain physical processes, some vendors actually can and do report the analytical total when there system has been suitably calibrated. While there are theoretical reasons why remote standards will never match the performance of true standards-based analysis, “remote standards” are a large step forward. However, not all vendors implement remote standards and no vendor documents sufficiently well what they actually do to turn our spectra into measures of composition. These shortcomings make us wonder to what extent a scientific endeavor can be based on black box software that has never been evaluated by an independent third-party to validate its reliability.
Solar Radiative Fluxes for Broken Cloud Fields above Reflecting Surfaces

Abstract A statistical bidirectional method for including the effects of underlying reflecting surfaces in Monte Carlo simulations of atmospheric photon transport is presented. It is illustrated for the idealized Lambertian surface and a general particulate surface. It is shown that the simple Lambertian surface should be an adequate approximation (to mildly anisotropic surfaces) for calculation of overall fluxes for broken cloud fields. The problem of incorporating multiple internal reflections of solar radiation between cloud and surface is reviewed, and cloud field reflectances to upwelling radiation rk as a function of the number of internal reflections k are calculated. Unlike plane-parallel and regular arrays of cloud, all rk are generally not equal for more realistic scaling cloud fields. Strictly speaking, this prohibits use of the familiar geometric sum formulas for flux calculation in a multiple reflecting system. Fortunately, though fortuitously, the geometric sum formulas can be used in such c.
Sewer sediment production and transport modelling: A literature review

This literature review presents the state-of-the-art concerning sediment sewer transport modelling. After a description of solid particles found in domestic sewage and in storm water, the different steps taken into account in models are described: build-up over the catchment, washoff by rainfall, transfer through gully pots, transport, deposition and erosion in sewer pipes. For each step, several modelling approaches are presented with their basic equations. The paper ends with a short presentation of some models, and with some remarks about the comparison between models and field experimental data.
On the evolution of quasars in clusters and central cluster galaxies

Les quasars radio-silencieux sont generalement trouves dans les groupes et amas de galaxies, et entoures d'un gaz intra-ams dense et refroidissant. Il est montre que le refroidissement Compton de ce gaz par le rayonnement des quasars peut produire une source d'energie auto-alimentee pour les objets les plus puissants.
A Domain Decomposition Method for the Solution of Large Electromagnetic Scattering Problems

A domain decomposition method (DDM) is presented for the solution of electromagnetic scattering problems by inhomogeneous 3-D bodies. The computational domain is partitioned into concentric subdomains on the interfaces of which Robin-type transmission conditions are prescribed. On the outer boundary terminating the computational domain, the radiation condition is taken into account by prescribing either an integral equation (IE) or an absorbing boundary condition. In the former case, the DDM decouples the inner problems, that correspond to the solution of Maxwell's equations inside each subdomain, from the outer problem solved by employing the IE. The convergence of the DDM algorithm to the solutions of the original problems is demonstrated when the dielectric permittivity and magnetic permeability tensors characterizing the inhomogeneous medium are those of passive materials.
GaS and InSe equations of state from single crystal diffraction

We have performed single crystal angle dispersive X‐ray diffraction at high pressure in order to investigate the GaS and InSe equations of state. We situate the transition from β‐GaS to GaS‐II at 2.7 ± 0.3 GPa. In the InSe experiment we locate the beginning of the phase transition at 7.6 ± 0.6 GPa. The equations of state of β‐GaS (V 0 = 43.27 ± 0.06 Å3, B = 37 ± 2 GPa, B ′ = 5.2), GaS‐II (V 0 = 42.4 ± 0.2 Å3, B = 50 ± 3 GPa and B ′ = 4.3 ± 0.3) and γ‐InSe (V 0 = 58.4 ± 0.2 Å3, B = 24 ± 3 GPa and B ′ = 8.6 ± 0.8) are discussed and compared with the results of an ab‐initio calculation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strong Cross-Barrier Flow under Stable Conditions Producing Intense Winter Orographic Precipitation: A Case Study over the Subtropical Central Andes

Abstract The most intense orographic precipitation event over the subtropical central Andes (36°–30°S) during winter 2005 was examined using observational data and a regional model simulation. The Eta-Programa Regional de Meteorologia (PRM) model forecast was evaluated and used to explore the airflow structure that generated this heavy precipitation event, with a focus on orographic influences. Even though the model did not realistically reproduce any near-surface variables, nor the precipitation shadow in the leeside lowlands, its reliable forecast of heavy precipitation over the windward side and the wind fields suggests that it can be used as a valuable forecasting tool for such events in the region. The synoptic flow of the 26–29 August 2005 storm responded to a well-defined dipole from low to upper levels with anomalous low (high) geopotential heights at midlatitudes (subtropical) latitudes located off the southeast Pacific coast, resulting in a large meridional geopotential height gradient that drov.
Global Attractivity Results for Nonlinear Delay Differential Equations

Abstract The aim of this paper is to give sufficient conditions for global attractivity of the zero solution of the nonlinear delay differential equationx′(t) = −p(t)f(x(t − τ)). An example which guarantees that our 3 2 stability condition is the best possible is also given.
Notes on the appropriateness of “bred modes” for generating initial perturbations used in ensemble prediction

Papers by Szunyogh and co-workers and Iyengar and co-workers, among others, claim that‘‘bred growing vectors’’ (BGVs) are appropriate for generating initial perturbations for applicationto ensemble weather prediction. The theoretical bases for this claim are purported relationshipsbetween the bred vectors and what are called local Lyapunov vectors (LLVs). Severalstatements in these papers are inaccurate, however, regarding: the properties of LLVs in contrastto those of singular vectors; the relationship between LLVs and BGVs; the relationship betweenBGVs and analysis errors; the relationship between singular vectors and dynamic imbalances;and the adequacy of very low-resolution models to characterize singular vectors of models usedfor numerical weather prediction. These inaccuracies and their implications for the use of BGVsin ensemble weather prediction are discussed here. DOI: 10.1034/j.1600-0870.1999. t01-3-00007.x
Measurement of coefficients for the back-scattering of 0.5-30 keV positrons from metallic surfaces

First measurements of the back-scattering coefficients for mono-energetic positrons of energies in the range 0.5-30 keV incident normally on Al, Cu, Ag and W samples are reported. The measured coefficients, which exhibit a small increase with energy in this energy range, and generally about 50% lower than reported values for electrons. Comparisons are made between the present results and earlier measurements at beta spectrum energies, and with recent Monte Carlo calculations.
Reply to ‘Comment on “On the dipole, velocity and acceleration forms in high-order harmonic generation from a single atom or molecule”’

We consider high-order harmonic generation from a single atom or molecule and show that the generated harmonic field is proportional to the dipole velocity. We derive this result by solving Maxwell's wave equation for an infinitely thin gas. Hence, the dipole velocity form is the one that relates directly to the harmonic field, and it should be used as a reference when performing calculations with the dipole or acceleration forms.
The Pólya–Szegö matrices in asymptotic models of dilute composites

The Pólya–Szegö dipole tensors are employed for the analysis of plane elasticity problems in non-homogeneous media. Classes of equivalence for defects (cavities and rigid inclusions) are specified for the Laplacian operator and elasticity equations: composite materials with defects of the same class have the same effective elastic moduli. Explicit asymptotic formulae for effective compliance matrices of dilute composites are presented.
Modulation of the two-photon absorption by electric fields in HgCdTe photodiode

We demonstrate the tunability of the two-photon absorption (TPA) coefficient by adjusting the electric field in a HgCdTe (MCT) photodiode with cutoff wavelength of 5. 2μm. The TPA coefficient was measured by using a picosecond pulsed laser with wavelength of 7. 92μm. An enhancement of the TPA coefficient occurs in the space charge region of the MCT pn junction, which can be attributed to the Franz–Keldysh effect induced by the built-in electric field. By applying a reverse bias to intensify the built-in field, the TPA coefficient is found to be further enhanced by a factor of 18.9. This electric field dependence of the TPA coefficient has been fairly interpreted by the pn junction model with the Franz–Keldysh effect included.
From Costly Signals and Competitive Niches to Reciprocity, Memes, and Memory Traces: Evolutionary Psychology and Strategic Communication

ABSTRACT This article gives an overview of the contributions in the special issue of the International Journal of Strategic Communication on evolutionary psychology and strategic communication. Forward-looking, it argues that recent advances in artificial intelligence (AI) have made it imperative for our discipline to come to grips with a biologized view of the human mind as an information-processing system that evolved to solve specific adaptive problems. Backward-looking, it tries to explain why evolutionary psychology, which offers such as perspective, has met with so much resistance in the social sciences.
Effects of shock impingement on the heat transfer around blunt bodies.

An extraneous shock impinging on a blunt body in hypersonic flow is observed to alter the flow around the body and increase the local heat-transfer rate near the impingement point. A novel, quasi-static technique is developed to study this phenomenon. A hemispherical, glass model, equipped with platinum thin-film thermometers, is injected into a hypersonic tunnel through a slot in a variable-incidence flat plate. Analog networks provide graphs of the heat-transfer rates at various points on the model as a function of the model's position relative to the extraneous shock. Peaks in local heat-transfer rates up to 10 times the local, unperturbed, freestream values are recorded as the model traverses the shock. The peak heating is severest on the side of the model nearest the plate and increases with increasing shock strength, occurring over a narrow region where a shear layer or jet, originating at the intersection of the bow shock and the impinging shock, meets the model surface. A physical model is set up which predicts variations in shock interference patterns, in surface pressure distributions, and in the intensity and extent of the peak heating in accordance with experiment. Nomenclature M = Mach number P = pressure normalized with respect to freestream pressure q = heat-transfer rate, cal-cm~2-sec~1 r = radius of hemisphere, mm t = time, sec T = temperature, °C U = velocity normalized with respect to freestream velocity V = injection speed, m-sec"1 x = distance along surface measured from stagnation point, mm
When a lattice homomorphism is a Riesz homomorphism

Let E and F be uniformly complete vector lattices with disjoint complete systems (ui )i ∈I and (vi )i ∈I of projection elements of E and F respectively. In this paper we prove that if T is a lattice homomorphism from E into F with T (λui ) = λvi for each λ ∈ ℝ and i ∈ I then T is linear. This generalizes the main results of [4] and [5]. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tearing mode in the cylindrical tokamak

Detailed computational results are presented on the stability and radial distribution of linear tearing modes in cylindrical tokamaks of various radial profiles. In the case of a skin‐current profile, a “double tearing mode”, with two points of discontinuity in the radial magnetic field perturbation is found. An analytical method is also derived for comparison of the stability of different radial profiles. It is further shown that the tearing mode can be driven by finite electron viscosity, as well as by the usual finite resistivity mechanism.
Engineering students’ conceptions of the derivative and some implications for their mathematical education

This paper explores Mechanical Engineering students’ conceptions of and preferences for conceptions of the derivative, and their views on mathematics. Data comes from pre-, post- and delayed post-tests, a preference test, interviews with students and an analysis of calculus courses. Data from Mathematics students is used to make comparisons with Mechanical Engineering students. The results show that Mechanical Engineering students’ conceptions of and preferences for the derivative develop in the direction of the rate of change aspects while those of Mathematics students develop in the direction of tangent aspects, and that Mechanical Engineering students view mathematics as a tool and want the application aspects in their course. Students’ developing conceptions, preferences and views with regard to teaching and departmental affiliation are considered and educational implications are suggested for the mathematical education of engineering students.
Characterization of nanoparticles by scanning electron microscopy in transmission mode

A conventional scanning electron microscope operated in transmission mode (TSEM) was used for imaging silica, gold and latex nanoparticles. Particles were applied to conventional transmission electron microscope (TEM) grids with different supporting films. A semiconductor detector capable of accomplishing both bright-field and dark-field imaging was used to record transmitted electrons. Particle diameter was determined from the images by comparing measured data with the results of corresponding Monte Carlo simulations which took into account particle and instrument properties. Measured and simulated line profiles agreed well; the method is sensitive to changes in diameter in the nano- and sub-nanometre range. It is concluded that TSEM imaging is a promising tool for dimensional characterization of nanoparticles. Necessary extensions to the technique in order to achieve traceable measurements are discussed.
SUPERSYMMETRY BETWEEN PHASE-EQUIVALENT COUPLED-CHANNEL POTENTIALS

With supersymmetric quantum mechanics, a coupled-channel potential is determined which is phase equivalent to a given one, and whose bound spectrum is identical except for one arbitrary bound state which is removed. The bound state is suppressed by a first supersymmetric transformation and the original scattering matrix is recovered with a second transformation. The resulting potential presents an r{sup {minus}2} singularity at the origin in some channels. The method is applied to the removal of the nonphysical state of the deep {sup 3}S{sub 1}-{sup 3}D{sub 1} neutron-proton Moscow potential and transforms it into a shallow potential with a repulsive core. {copyright} {ital 1997} {ital The American Physical Society}
The generalized group technology concept

In this paper two classes of clustering models are considered: (1) matrix, and (2) integer programming. The relationship between the matrix model, the p-median model and the classical group technology concept is discussed. A generalized group technology concept, based on generation for one part of a number of different process plans, is proposed. This new concept improves the quality of process (part) families and machine cells. A corresponding integer programming model is formulated. The models discussed are illustrated with numerical examples.
Comparison between kinetic-ballooning-mode-driven turbulence and ion-temperature-gradient-driven turbulence

Electromagnetic turbulence driven by kinetic ballooning modes (KBMs) in high-β plasma is investigated based on the local gyrokinetic model. Analysis of turbulent fluxes, norms, and phases of fluctuations shows that KBM turbulence gives narrower spectra and smaller phase factors than those in ion-temperature-gradient (ITG)-driven turbulence. This leads to the smaller transport fluxes in KBM turbulence than those in ITG turbulence even when they have similar linear growth rates. From the analysis of the entropy balance relation, it is found that the entropy transfer from ions to electrons through the field-particle interactions mainly drives electron perturbations, which creates radial twisted modes by rapid parallel motions of electrons in a sheared magnetic geometry. The nonlinear coupling between the dominant unstable mode and its twisted modes is important for the saturation of KBM turbulence, in contrast to the importance of zonal flow shearing in ITG turbulence. The coupling depends on the flux-tube domain with the one-poloidal-turn parallel length and on the torus periodicity constraint.
A comprehensive study of the $\delta$ Scuti star AN Lyncis

We present new time-series CCD photometry on the δ Scuti star AN Lyn. Analyses based on all the available data show that the amplitude of the main frequency increased from 1994 to 2000 at a rate of 0.006 mmag yr - 1 . Considering all the existing amplitudes, the amplitude variations seem sinusoidal since 1980. In both periods of 1980-1983 and 1994-2001 with data available the amplitudes increased linearly with time. The amplitudes in the earlier 1980s were higher and they increased at a higher rate than those in 1994-2001. Amplitude variations of the other frequencies are also present from season to season. The light variation of AN Lyn can be explained currently by amplitude variability plus multiperiodic pulsation. However, no conclusion can be drawn regarding change of periods and new oscillation contents. The two independent frequencies f 1 = 10.1756 cycle d - 1 and f 2 = 18.1310 cycle d - 1 are confirmed and are suggested to be the solution of the light variation of AN Lyn. The mixture of radial and nonradial modes of the two frequencies most likely characterize the pulsation of the star.
Theory of electroluminescence intensity and insights into recombination in thin film solar cells

Equations describing the electroluminescence (EL) intensity as a function of material properties are derived for thin film solar cells and experimentally validated using Cu(In,Ga)Se2 solar cells. EL intensity at constant voltage is controlled by the electronic properties of the neutral bulk even when the diode current is controlled by recombination in the space charge region. Using a combination of techniques, it is found that recombination in the quasineutral bulk does not correlate with recombination in the space charge region. Differences between EL measurements on thin film cells and crystalline silicon cells are discussed including the effects of secondary barriers.
Acceleration of soliton by nonlinear Landau damping of dust-helical waves

The problem of nonlinear Landau damping of helicon waves in dusty plasma in particular emphasis to the acceleration of soliton is presented here. This in the framework of a collisionless, anisotropic homogeneous dusty plasma in one dimension, can be well described by two coupled dynamical equations of the generalized Zakharov type, with one extra nonlocal term coming from Landau damping. Nonlinear-nonlocal term gives rise to essential contributions relative to the local term. Then under different conditions, kinetic nonlinear Schrodinger equation is constructed and nonlinear decrement is obtained for two cases. It is noticed that the time dependant term in the ponderomotive force plays a significant role for this kind of damping. Additionally, it is shown that nonlinear Landau damping leads to the amplitude modulation of dust helicon waves, further modulational instability, and maximal growth rate is obtained when the group velocity of the helicon wave reaches the dust-acoustic speed. It is demonstrated t.