Miracle-dz/UniFAR-FTUs huggingface dataset:
Simulations of phase space distributions of storm time proton ring current

We use results of guiding-center simulations of ion transport to map phase space densities of the stormtime proton ring current. We model a storm as a sequence of substorm-associated enhancements in the convection electric field. Our pre-storm phase space distribution is an analytical solution to a steady-state transport model in which quiet-time radial diffusion balances charge exchange. This pre-storm phase space spectra at L∼2-4 reproduce many of the features found in observed quiet-time spectra. Using results from simulations of ion transport during model storms having main phases of 3, 6, and 12 hr, we map phase space distributions from the pre-storm distribution in accordance with Liouville's theorem. We find stormtime enhancements in the phase space densities at energies E∼30-160 keV for L∼2.5-4. These enhancements agree well with the observed stormtime ring current. For storms with shorter main phases (∼3 hr), the enhancements are caused mainly by the trapping of ions injected from open night side trajectories, and diffusive transport of higher-energy (≳ 160 keV) ions contributes little to the stormtime ring current. However, the stormtime ring current is augmented also by the diffusive transport of higher-energy ions (E≳ 160 keV) during storms having longer main phases (≳ 6 hr). In order to account for the increase in Dst associated with the formation of the stormtime ring current, we estimate the enhancement in particle-energy content that results from stormtime ion transport in the equatorial magnetosphere. We find that transport alone cannot account for the entire increase in |Dst| typical of a major storm. However, we can account for the entire increase in |Dst| by realistically increasing the stormtime outer boundary value of the phase space density relative to the quiet-time value. We compute the magnetic field produced by the ring current itself and find that radial profiles of the magnetic field depression resemble those obtained from observational data.
Spatial information of sound fields for room‐acoustics evaluation and diagnosis

Numerous subjective attributes of the listening experience in auditoria, particularly concert halls, can be described by the many available contemporary room‐acoustic indicators. Subjective response is also known to be influenced by the spatial distribution of sound energy. The spatial distribution is not only desirable to diagnose acoustical defects, but also to visualize and quantitatively appreciate the extent to which the various interior design features influence acoustic quality. The objective of the present work is to demonstrate the usefulness of spatial acoustic information for quality assessment and defect diagnosis within enclosures. A new measurement method based on transient sound intensity is employed for obtaining the spatial information and examples of applications are presented together with a discussion of the method’s potential.
Dynamics Inside Polymer Drops: From Dimple to Rayleigh Instability to Torus

The free boundary shape of a rising bubble or falli drop is a sensitive measure of the balance of the interior exterior fluid forces. When the drop phase is a dilute polym solution, a number of new instabilities occur. 1 Our experiments involve an aqueous solution of 0.2% Xanthan g ~polymer! in 80:20 glycerol/water falling through PDMS o ~viscosity of 10 Stokes ! The polymer drop is introduced a the top of an oil-filled column as a roughly spherical globu and its steady state shape is observed from 30–60 cm d the column. Typically, the drops can have Reynolds numb up to 2, and Deborah numbers up to 4. At a volume of 0 ml, the drop is spherical, while for volumes from 0.05–0. ml, the drop has an oblate spheroidal shape. Above a cri volume of 0.25 ml, a dimple is observed at the rear of drop ~Fig. 1! It is well known that a transition to dimpled drops occurs due to inertial effects. However, the deform tion we observe is not due to inertia, confirmed by t spherical shape of the same drop without the polymer. As volume of the drop is increased further, the dimple becom unstable, and is pulled down into the drop ~Fig. 2! This has FIG. 4. 6.2 ml.
On entry-flow effects in bifurcating, blocked or constricted tubes

For practically uniform entry conditions, the features of the steady laminar flow produced by a particular small distortion of the walls of a channel or pipe are shown to alter first from those of the corresponding external situation when the distortion is in an ‘adjustment zone’, sited a large distance O(R⅗l) from the inlet; R ([Gt ] 1) and l signify respectively a typical Reynolds number and length scale of the incompressible fluid motion. The planar channel flow there develops an extended triple-deck structure, with an unknown inviscid core motion bounded by two-tiered boundary layers near the walls. In three-dimensional pipe flow, where a similar structure occurs, the induced secondary motion has a jet-like nature close to the wall. The size and position of the indentation govern the flow properties within this adjustment regime and both can lead to large-scale effects being propagated. The most substantial effects occur if an indentation, interior blockage or bifurcation is sited just downstream of the adjustment stage in a channel. In a pipe, however, such a siting induces much less upstream influence, and instead the most significant long-scale disturbances are generated when the pipe is constricted asymmetrically over a small length. Vortex motion can then be provoked far beyond the constriction, the sense of rotation changing as the fluid moves further downstream, while upstream source-like secondary flow is found.
OBSERVATION OF HIGH-SPEED OUTFLOW ON PLUME-LIKE STRUCTURES OF THE QUIET SUN AND CORONAL HOLES WITH SOLAR DYNAMICS OBSERVATORY/ATMOSPHERIC IMAGING ASSEMBLY

Observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory reveal ubiquitous episodic outflows (jets) with an average speed around 120 km s−1 at temperatures often exceeding a million degree in plume-like structures, rooted in magnetized regions of the quiet solar atmosphere. These outflows are not restricted to the well-known plumes visible in polar coronal holes, but are also present in plume-like structures originating from equatorial coronal holes and quiet-Sun (QS) regions. Outflows are also visible in the “inter-plume” regions throughout the atmosphere. Furthermore, the structures traced out by these flows in both plume and inter-plume regions continually exhibit transverse (Alfvénic) motion. Our finding suggests that high-speed outflows originate mainly from the magnetic network of the QS and coronal holes (CHs), and that the plume flows observed are highlighted by the denser plasma contained therein. These outflows might be an efficient means to provide heated mass into the corona and serve as an important source of mass supply to the solar wind. We demonstrate that the QS plume flows can sometimes significantly contaminate the spectroscopic observations of the adjacent CHs—greatly affecting the Doppler shifts observed, thus potentially impacting significant investigations of such regions.
Composition of interstellar gas and dust

The composition of interstellar dust is normally inferred indirectly, from analyses of gas-phase abundances and an assumed total interstellar medium composition, providing data on the depletions of elements from the gas. Additional information comes from infrared observations of solid-state absorption bands (usually applicable only to dense clouds), from X-ray absorption and scattering measurements, and from the analysis of components of interplanetary dust particles. This review is focused on issues related to interstellar gas-phase abundances and depletions, and the question of appropriate reference abundance standards. The paper includes an overview of gas-phase abundance measurements, a summary of depletions as derived from the adoption of solar or stellar reference abundances, comments on the impact of depletion measures on the inferred dust composition, and a discussion of alternatives to the adoption of solar or stellar reference abundances. The paper concludes with a description of new instruments, soon to be in operation, that should help to resolve some of the issues.
Simple non-iterative calibration for triaxial accelerometers

For high precision measurements, accelerometers need recalibration between different measurement occasions. In this paper, we derive a simple calibration method for triaxial accelerometers with orthogonal axes. Just like previously proposed iterative methods, we compute the calibration parameters (biases and gains) from measurements of the Earth's gravity for six different unknown orientations of the accelerometer. However, our method is non-iterative, so there are no complicated convergence issues depending on input parameters, round-off errors, etc. The main advantages of our method are that from just the accelerometer output voltages, it gives a complete knowledge of whether it is possible, with any method, to recover the accelerometer biases and gains from the output voltages, and when this is possible, we have a simple explicit formula for computing them with a smaller number of arithmetic operations than in previous iterative approaches. Moreover, we show that such successful recovery is guaranteed if the six calibration measurements deviate with angles smaller than some upper bound from a natural setup with two horizontal axes. We provide an estimate from below of this upper bound that, for instance, allows 5° deviations in arbitrary directions for the Colibrys SF3000L accelerometers in our lab. Similar robustness is also confirmed for even larger angles in Monte Carlo simulations of both our basic method and two different least-squares error extensions of it for more than six measurements. These simulations compare the sensitivities to noise and cross-axis interference. For instance, for 0.5% cross-axis interference, the basic method with six measurements, each with two horizontal axes, gave higher accuracy than allowing 10° deviation from horizontality and compensating with more measurements and least-squares fitting.
Doing without [tense/lax] in English

In the phonological account of the vowel system of English, there has been controversy over whether or not the feature pair [tense/lax] is required as a distinctive feature, along with [long/short]. While several phonologists since Chomsky and Halle (1968) have made use of [tenseness] along with [length], others including Lass (1976) and Durand (2005) have either dismissed [tense/lax] as contentless or maintained that it is not required as part of the English vowel inventory. In this paper, we attempt to contribute to the position that [tense/lax] as a distinctive feature can be dispensed with at least in the phonological account of the English vowel system. We will also present an optimality-theoretic account of various surface realizations of English vowels. We will show that all surface vowel patterns of English can be derived without resorting to the feature [tense/lax]; thus some major constraints such as μμ↔tense and *V[lax]# posited by previous studies including Lee (2003) can be eliminated from the English vowel system for the sake of simplicity. (Dongduk Women`s University)
More on the volatility-trading volume relationship in emerging markets: The Chinese stock market

This paper empirically investigates the characteristics in terms of volatility and trading volume relationships of the Chinese stock markets, and specifically of the stocks comprising the SSE180 index. Our results show that, contrary to previous evidence, both volatility and trading volume appear to be multi-fractal and highly intermittent, suggesting a common long-run behaviour in addition to the common short-term behaviour underlined by former studies. Moreover, the trading volume seems to have no explanatory power for volatility persistence when introduced in the conditional variance equation. Finally, the sign of the trading volume coefficients is mainly negative, hence showing a negative correlation between the two variables.
Simulations of density profiles, pellet fuelling and density control in ITER

The paper presents the results of 1.5-dimensional simulations of density profiles and pellet fuelling for the ITER baseline scenario performed with the ASTRA and JETTO transport codes by the ITER Scenario Modelling working group within the European Task Force on Integrated Tokamak Modelling. The first part of the paper describes the physics of the problem and how it is implemented in the different codes available to the working group. The second part presents the results of the simulations. Results obtained with the GLF23 physics based transport model and a simplified description of the pellet particle source are described alongside results obtained with the simpler Bohm/gyro-Bohm semi-empirical transport model and a more sophisticated pellet ablation/deposition code providing a completely self-consistent description of the pellet source. A parametric study has been performed to assess the effect of varying parameters independently, the values of which in ITER are either uncertain or not easily controllable (such as particle diffusivity, edge stability, wall recycling and boundary conditions), on the target plasma density, temperature, Q and pellet frequency required to achieve a certain degree of density control. To this end the edge particle diffusivity was increased by a factor of three, the pedestal normalized critical pressure gradient for ballooning stability was decreased by 20%, the boundary conditions on density and temperature were modified by 30–40% and the wall recycling particle source was increased from zero to 20% of the particle outflux. The results show that variations in the order of 15% for density and temperature, 40% for Q and 100% for the pellet frequency can be expected. Open problems and modelling needs are also discussed in the paper.
Scaling of the correlations among segment directions of a self-repelling polymer chain

Segment directions in a self-repelling polymer chain are expected to show nontrivial universal long-range correlations. We verify this hypothesis to two-loop order of renormalized perturbation theory and we calculate the scaling function using the -expansion to order 2. The result is well confirmed by simulations of the Domb-Joyce model on a simple cubic lattice. Furthermore, it explains previous simulation results. Our results have consequences for the interpretation of the persistence length in screened polyelectrolytes.
A transputer‐based measuring system for decentralized signal processing, applied to two‐phase flow

An innovative concept for decentralized processing of the signals of multiple sensors is presented. The basic idea is to connect every sensor via an analog‐to‐digital converter with a high‐performance microprocessor, a transputer, that exclusively collects and processes its signal. The transputers are linked to a powerful network. Exemplarily, a measuring system based on this concept was used for the determination of local parameters of liquid–gas two‐phase flows (e.g., local void fraction and bubble frequency). Up to six fiber‐optical probes were utilized simultaneously to demonstrate the efficiency of the system. The signal processing under that special application may include on‐line evaluation of flow parameters and on‐line correction of errors of measurement due to sensor‐induced effects. The concept of the new system, however, is basically independent of the number and type of sensors, as well as of the method of signal processing. The transputer‐based measuring system thus provides a flexible, effi.
Investigation of low loss Z-type hexaferrites for antenna applications

Z-type hexaferrites in series (Ba0.5Sr0.5)3Co2Fe24O41 + xWO3 (where x = 0.0, 0.1, 0.2, 0.3, and 0.4 wt. %) were prepared by a conventional ceramic technique. The addition of WO3 has been used to enhance sintering density and magneto-dielectric properties of low loss Co2Z ferrites. A second phase of BaWO4 can be found in the XRD patterns. The replacements of hexagonal phase by high valence W6+ ions improved sintering and accelerated density of the ferrites, which resulted in the increase of real permeability. Due to the formation of Fe2+, excessive WO3 resulted in undesired high permittivity and dielectric loss tangent. Comparatively, a ferrite sample with 0.2 wt. % WO3 gave the best performances in terms of density, microstructure, magneto-dielectric property, and loss tangent. Since loss tangent was kept low with the frequency ranging from 10 to 300 MHz, such magneto-dielectric material could be used in this frequency range for antenna applications.
Drag heating of gas in rich superclusters

Clusters moving through an intrasupercluster gas of density ∼10 −6 cm −3 experience strong gravitational drag. The associated heating probably raises the gas temperature up to ∼ 5 × 10 7 K. If the gas is detectable at all, it should be searched for in the few-keV region
A numerical study of a rotationally degenerate hyperbolic system. Part II. The Cauchy problem

In this paper a numerical method is proposed for obtaining stable solutions to the initial-value problem for the pair of conservation laws \[ (0.1)\qquad U_t + \left( {\left| U \right|^2 U} \right)_x = 0 \] where $U \in \mathbb{R}^2 $. These equations constitute a standard model describing small amplitude plane wave solutions to rotationally invariant partial differential equation (PDE) systems arising in continuum mechanics. In particular, viscous regularization of (0.1) by $\epsilon U_{xx} $ is not uniform as $\epsilon \to 0$. Therefore finite difference schemes, which include numerical dissipation of this type, fail to approximate certain dynamically stable weak solutions of the inviscid system (0.1). Our proposal is to extend the system and solve the three conservation laws \[ \begin{gathered} r_t + \left( {r^3 } \right)_x = 0,\hfill \\ (0.2)\qquad U_t + \left( {r^2 U} \right)_x = 0 \hfill \\ \end{gathered}\] with data $(r^0 ,U^0 )$ satisfying $r^0 = |U^0 |$. The solutions $(r_\epsilon ,U_\epsilon )$ o.
Tailored domain wall charges by individually set in-plane magnetic domains for magnetic field landscape design

A method, a material system, and the physics for tailoring artificial magnetic field landscapes on micron and submicron length scales over a topographically flat surface in remanence are presented. KeV-He+ ion bombardment induced magnetic patterning was used for the creation of in-plane magnetized domains in Exchange Bias layer systems. This technology sets defined magnetic domain wall charges between the in-plane magnetic domains by individually set domain properties (magnitude and direction of anisotropy parameters) on both sides of the domain wall. The magnetic surface charge distribution was analyzed by magnetic force microscopy and compared to micromagnetic simulations.
Non-linear interactions in a viscous heat-conducting compressible gas

The linearized equations of motion show that in a viscous heat-conducting compressible medium three modes of fluctuations exist, each one of which is a familiar type of disturbance. The vorticity mode occurs in an incompressible turbulent flow, the entropy mode is familiar as temperature fluctuations in low speed turbulent heat transfer problems, and the sound mode is the subject of conventional acoustics. A consistent higher order perturbation theory is presented with the only restrictions being that the Prandtl number is 3/4 and the viscosity and heat conductivity are monotinic functions of the temperature alone. The theory is based on expansion of the disturbance fields in powers of an amplitude parameter α. The non-linearity of the full Navier-Stokes equations can be interpreted as interaction between the three basic modes; in order to help physical insight the interactions are classed as ‘mass-like’, ‘force-like’, and ‘heat-like’ effects. Besides the amplitude parameter α there is another subsidiary non-dimensional parameter ε which indicates the relative importance of viscosity and heat conduction effects as compared to the inertial effects, ε is proportional to the ratio of the molecular mean free path and the characteristic length of the flow pattern (Knudsen number). The main contribution of the paper is the outline of a consistent successive approximation for an arbitrary order in α and the presentation of explicit formulae for the second order (bilateral) interactions. A special case of rather general significance is treated in more detail. This is when all three basic modes have intensities and length scales of the same orders of magnitude and in addition to α the parameter ε is also small; the second-order interactions are then relatively few and easily identifiable and are shown in table 1. The present analysis also sheds some light on the ‘zero order’ approximation which treats the vorticity and entropy disturbances as a ‘frozen pattern’ and the sound field as propagating nondissipative waves. The interpretation of hot-wire measurements relies heavily on these simplified models and the present paper lends some support to these current hot-wire practices.
Experimental Studies of the Production of Converging Cylindrical Shock Waves

AN improved experimental technique for the production of cylindrical converging shock waves is presented. This is accomplished with an annular shock tube fitted with an axisymmetric area contraction which redirects an annular incident shock into a cylindrical implosion chamber. The contraction profile is designed in accordance with Whitham's ray-shock theory, and a three-element profile is found to provide the best overall performance on the basis of twodimensional tests. Experiments with a three-element conical contraction demonstrate that highly symmetrical cylindrical implosions may be achieved by this method, and that the cylindrical shock amplification is well predicted by the Chester-Chisnell-Whitham (CCW) area Mach No. rule.
A numerical simulation of hydrodynamic forces of ground-effect problem using Lagrange's equation of motion

SUMMARY On the basis of the potential flow theory, Lagrange’s equation of motion is used to study the unsteady ground-effect problem. The forces and moments acting on the moving body are solved in terms of the derivatives of added masses in which the generalized Taylor’s formulae are applied. The singular integral equations used to solve the surface source intensities and their derivatives are regularized by the Gauss flux theorem and are therefore amenable to the direct use of the Gaussian quadrature formula. In illustration, the condition of a prolate spheroid moving in the fore-and-aft direction at constant speed past a flat ground with a protrusion is considered. The hydrodynamic forces and moments acting on the moving spheroid are investigated systematically by varying the size of the protrusion and the cruising height of the spheroid. © 1998 John Wiley & Sons, Ltd.