Miracle-dz/UniFAR-FTUs huggingface dataset:
Analysis of MHD equilibria by toroidal multipolar expansions

The use of fully toroidal co-ordinates permits the two-dimensional problem of the axisymmetric plasma toroidal equilibrium to be reduced to the one-dimensional problem of determining a limited number of its toroidal multipolar moments. This has allowed the creation of a fast semi-analytic predictive equilibrium code that can be used in both free and fixed boundary conditions for plasmas with circular or mildly noncircular cross-section. The concept of toroidal multipoles is also particularly suitable for the analysis of experimental data from magnetic probe measurements and clarifies the conditions under which the plasma thermal and electrical self-inductances βp and ℓi can be estimated separately. Finally, the interpretation of the magnetic equilibrium measurements in terms of toroidal multipoles can directly provide the boundary conditions for a fast equilibrium reconstruction code. Examples of the application of such a code to the JET magnetic measurements are reported.
Time-Series Observations of O Stars. III. IUE and HST Spectroscopy of zeta Ophiuchi and Implications for the ``Photospheric Connection''

Stellar-wind variability in the archetypal nonradially pulsating O star ζ Oph (O9.5 V) is discussed on the basis of new time-series IUE and HST spectroscopy and archival results. Time-variable discrete absorption components are first observed at high velocities (≥10 3 km s −1 ≃0.8v∞) and then migrate blueward; the recurrence time scale for the phenomenon is ∼20 hr. This is the first record of this type of variability in a luminosity-class V star and provides support for the previously inferred ubiquity of such behavior across the O-star regime. The accelerations are slower than predicted by steady state wind models and are unlikely to represent the time-averaged velocity law of the outflow
Vestibular Response to Sound: Single‐Unit Recording from the Vestibular Nerve in Fenestrated Deaf Mice (Df/Df)

Deaf mice of the Df/Df strain have degenerated cochleae but histologically‐normal vestibular structures. After fenestration of the horizontal semicircular canal, tones and clicks were delivered to the fenestrated ear through the external auditory canal, using a closed sound system. Single units of the vestibular nerve were picked up by tungsten microelectrodes. Single‐unit responses were obtained only in fenestrated animals and only for frequencies from 80 to 4200 cps. Threshold was best for 1500 cps, and was at 78 dB re 0.0002 dyn/cm2. Click responses were also obtained. Some units with spontaneous activity were driven by tone bursts; others were inhibited. Spontaneous activity was present in single units of nonfenestrated mice but was not altered by tones or clicks, and no units were driven by either type of sound stimulus. [Work supported by grants from the National Institute of Neurological Diseases and Blindness, National Institutes of Health, U. S. Department of Health, Education, and Welfare, and by the Alfred P. Sloan Foundation. ]
Nonlinear wavy phenomena into plasma: some cases of stabilization and control of chaotic behaviors

Abstract Stabilities, instabilities and turbulences have always appeared into a cylindrical magnetized argon plasma. These phenomena are caused by linear or nonlinear dynamics and are interpreted with the linear or nonlinear theory accordingly. In this paper, an experimental study accompanied by theoretical justification and based on the wave–wave interaction has been made; an azimuthally moved driving wave is enforced in a very simple way. The turbulence stabilization, the wave coupling, the instability synchronization and other wavy interactions, which are caused by using an external spatiotemporal electric signal, are presented. The research of the wavy subjects continuing in our laboratory aspires to comprehend the plasma chaotic behavior and take a step into suppressing the unstable inclination.
Sub-Laplacians with drift on Lie groups of polynomial volume growth

Introduction and statement of the results The control distance and the local Harnack inequality The proof of the Harnack inequality from Varopoulos's theorem and propositions 1.6. 3 and 1.6. 4 Holder continuity Nilpotent Lie groups Sub-Laplacians on nilpotent Lie groups A function which grows linearly Proof of propositions 1.6. 3 and 1.6. 4 in the case of nilpotent Lie groups Proof of the Gaussian estimate in the case of nilpotent Lie groups Polynomials on nilpotent Lie groups A Taylor formula for the heat functions on nilpotent Lie groups Harnack inequalities for the derivatives of the heat functions on nilpotent Lie groups Harmonic functions of polynomial growth on nilpotent Lie groups Proof of the Berry-Esseen estimate in the case of nilpotent Lie groups The nil-shadow of a simply connected solvable Lie group Connected Lie groups of polynomial volume growth Proof of propositions 1.6. 3 and 1.6. 4 in the general case Proof of the Gaussian estimate in the general case A Berry-Esseen estimate for the heat kernels on connected Lie groups of polynomial volume growth Polynomials on connected Lie groups of polynomial growth A Taylor formula for the heat functions on connected Lie groups of polynomial volume growth Harnack inequalities for the derivatives of the heat functions Harmonic functions of polynomial growth Berry-Esseen type of estimates for the derivatives of the heat kernel Riesz transforms Bibliography.
One-dimensional explicit finite-volume model for sediment transport

A 1D finite-volume model has been established to simulate the nonequilibrium transport of nonuniform sediment with transient flows, such as dam-break flow and overtopping flow, over movable beds. The effects of sediment transport and bed change on the flow are considered in the flow continuity and momentum equations. An explicit algorithm is adopted to solve the governing equations. The model has been tested preliminarily in several experimental cases, including an experiment on wedge development due to sediment overloading under transcritical flow conditions, an experiment on dam surface erosion due to overtopping flow, and two experiments on dam-break flow over movable beds. The model performs quite well in the cases of wedge development and overtopping flow, but significantly under-predicts the bed erosion due to dam-break flow. A modification has thus been made by considering the effects of sediment concentration on sediment settling and entrainment in the case of dam-break flow over movable beds. The present model has been compared with the traditional movable-bed “clear-water” model that ignores the effects of sediment on the flow. It has been found that the present model provides more reasonable predictions, and the “clear-water” model has larger errors when sediment transport is stronger and may even fail in the case of dam-break flow.
Singular perturbations and a free boundary problem in the modeling of field-effect transistors

The drift-diffusion equations of semiconductor physics, modeling the behavior of buried-channel field-effect transistors, are analyzed using formal perturbation techniques. For large aspect ratio devices, the potential distribution is essentially one-dimensional under the gate and has a boundary layer structure near the source and drain. By extending the results of Ward, Odeh, and Cohen [SIAM J. Appl. Math., 4 (1990), pp. 1099–1125], where a different class of devices was treated, the potential under the gate is resolved in the limit of large doping densities for various values of the gate voltage and implant depth. Using the asymptotic potential, the mobile charge, which is needed for the derivation of the long-channel current-voltage relations, is found using standard techniques in the asymptotic evaluation of integrals. The results of Ward, Odeh, and Cohen are also extended to analyze the potential distribution in the fully two-dimensional regions near the source and drain in equilibrium. In the limit .
The numerical solution of eigenvalue problems

1. P. Brock & F. J. Murray, "The use of exponential sums in step by step integration," MTAC v. 6, 1952, pp. 63-78. MR 13, 873. 2. W. Gautschi, "Numerical integration of*ordinary differential equations based on trigonometric polynomials," Numer Math., v. 3, 1961, pp. 381-397. MR 86 *1647. 3. E. Remes, "Sur le calcul effectif des polynômes d'approximation de Tchebycheff," C. R. Acad. Sei. Paris, v. 199, 1934, pp. 337-340. 4. H. Maehly, "Methods for fitting rational approximations," Parts II & III, J. Assoc. Comput. Mach. , v. 10,1963, pp. 257-277. MR 28 «707. 5. J. Stoer, "A direct method for Chebyshev approximation by rational functions," J. Assoc. Comput. Mach. , v. 11,1964, pp. 59-69. 6. P. Wynn, "Über einen Interpolations-Algorithmus und gewisse andere Formeln, die in der Theorie der Interpolation durch rationale Funktionen bestehen," Numer. Math., v. 2, 1960, pp. 151-182. MR 23 *B1636. 7. Z. Kopal, "Operational methods in numerical analysis based on rational approximation," Proceedings of a Symposium on Numerical Approximation (1958), R. E. Langer (Ed.), Publication No. 1, Mathematics Research Center, Univ. of Wisconsin, Univ. of Wisconsin Press, Madison, 1959, pp. 25-43. 8. J. D. Lambert & A. R. Mitchell, "On the solution of y' •= f(x, y) by a class of high accuracy difference formulae of low order," Z. Angew. Math. Phys., v. 13, 1962, pp. 223-232. MR 25 *3610.
A mechanism for the barotropic equilibration of baroclinic waves

Abstract The barotropic instability of finite amplitude waves is suggested as a mechanism for explaining the equilibration of a baroclinic wave growing in a meridionally independent vertical shear flow. A quasigeostrophic two-layer channel model on an f-plane is used to give evidence for this hypothesis. Three solutions with different flow symmetries are adopted for the analysis. Numerical simulations reveal that the flow symmetry of the initial small amplitude perturbation can have a large impact on wave structure evolution and energetics. The flow symmetry of the first solution forces the wave to excite symmetric life cycles with baroclinic growth and baroclinic decay. The flow symmetries of the other solutions enable the wave to undergo an asymmetric life cycle with baroclinic growth followed by a barotropic decay that occurs when the fundamental wave has a sufficiently large aspect ratio. Accordingly, a linear-stability analysis of a steady barotropic wave reveals an increasing destabilization with in.
Cosmic ray intensity during the passage of coronal mass ejections

Coronal Mass Ejections are vast structures of plasma and magnetic fields that are expelled from the sun into the heliosphere. This material is detected by remote sensing and in-situ spacecraft observations. The present study deals with the influence of four types of CMEs namely Asymmetric ’Full’ Halo CMEs, Partial Halo CMEs, Asymmetric and Complex ’Full’ Halo CMEs and ’Full’ Halo CMEs on cosmic ray neutron monitor intensity. The data of ground based neutron monitor of Moscow and CME events observed with instruments onboard and Wind spacecraft have been used in the present analysis. The method of superposed epoch (Chree) analysis has been used to the arrival times of these CMEs. It is noteworthy that the frequency of occurrence of Asymmetric ’Full’ Halo CMEs is significantly high, whereas frequency of occurrence of Asymmetric and Complex ’Full’ Halo CMEs is low compared to other CMEs. Significant enhancement in cosmic ray intensity is observed after 4 days of the onset of asymmetric full halo and 6 days after the onset of full halo CMEs. The fluctuations in cosmic ray intensity are more prior to the onset of both types of the CMEs. However, during Partial Halo CMEs the cosmic ray intensity peaks, 8- 9 days prior to the onset of CMEs and depressed 3 days prior to the onset of CMEs, whereas in case of asymmetric and complex full CMEs, the intensity depressed 2 days prior to the onset of CMEs and enhanced 2 days after the onset of CMEs. The deviations in cosmic ray intensity are more pronounced in case for asymmetric and complex full halo CMEs compared to other CMEs.
Experiments on speed-enhanced neutron yield from a small plasma focus

In order to operate a plasma focus at high axial sheath velocities, the geometry of the inner electrode (anode) of a 3 kJ Mather-type device was modified. Double-stage stepped-anode configurations were tested with the speed-enhanced region sufficiently long for a significant increase in speed but not long enough to allow the development of force-field flow-field separation at the end of the axial phase. Peak axial speeds up to 15 cm μs−1 were achieved. The neutron and soft X-ray productions were found to be sheath-velocity-dependent. A new scaling law for the non-beam component of the neutron yield is proposed.
Orbital evolution by dynamical tides in solar type stars. Application to binary stars and planetary orbits

We study the tidal evolution of eccentric binary systems consisting of a solar type main sequence star accompanied by either another solar type star, or by a planet with a mass similar to Jupiter's mass. The tidal dissipation which takes place in the solar type star(s) is calculated in the framework of dynamical tides, and resonant interaction with the g-mode and quasi-toroidal oscillation eigenmodes of the stellar component(s) is included in the orbital calculations. It appears that in a system of two solar type stars intervals during which harmonic components of the perturbing tidal potential become locked onto resonances with stellar oscillation modes appear ubiquitously, signicantly enhancing the eciency of the tidal coupling. In our calculations stellar binaries become circularized during the main sequence lifetime for orbital periods up to about 10 days, or 16 days in the case of very slow stellar rotation. Ecient resonance locking causes signicant tidal decay in weakly eccentric planetary binaries with orbital periods up to approximately 5 days in case the solar type star is a slow rotator, and very large increase of the orbital period and eccentricity in case the star is rotating rapidly. The dynamical tide with inclusion of the eects of close resonances with the stellar oscillation modes provides considerably more ecient tidal coupling than the equilibrium tide with viscous damping of turbulent eddies.
Atomic distribution in In x Ga 1-x N single quantum wells studied by extended x-ray absorption fine structure

The anisotropy of the local structure around In atoms in high quality In{sub x}Ga{sub 1-x}N (x=0.145,0.20,0.275) single quantum wells (SQWs) was investigated by fluorescence extended x-ray absorption fine structure measurements using linearly polarized x ray whose electric field was set to be both horizontal and vertical to the SQWs. The interatomic distance was isotropic for the nearest In-N, whereas for the second nearest In-Ga and In-In, the interatomic distance for out-of-plane atoms was longer than that for in-plane atoms. From the analyses of the coordination number for In-In and In-Ga, the In atom distribution in the In{sub 0.275}Ga{sub 0.725}N SQW was found to be statistically random in both directions. On the other hand, In atoms in the In{sub 0.20}Ga{sub 0.80}N SQW, corresponding to green light-emitting diodes (LEDs), were randomly distributed in the horizontal direction but aggregated in the vertical direction. Correlation was suggested between the vertical aggregation and the higher efficiency of InGaN-based blue to green LEDs.
Impact of SST on Precipitation and Snowfall on the Sea of Japan Side in the Winter Monsoon Season: Timescale Dependency

We investigated the impact of the sea surface temperature (SST) over the Sea of Japan on precipitation and snowfall on the Sea of Japan side of Honshu, Japan, using precipitation and snowfall data from Automated Meteorological Data Acquisition System (AMeDAS) stations, records of sea level pressure from meteorological stations, wind fields from the Japanese 25-year reanalysis (JRA25) dataset, and multiple SST datasets. We examined the data on various timescales from daily to monthly because SST over the Sea of Japan also varies on timescales shorter than a month. The results showed that the impact of SST over the Sea of Japan on precipitation on the Sea of Japan side was strongly timescale-dependent. On the shorter intraseasonal timescales of several days to a few weeks, SST had a clear impact on precipitation, while the impact was indistinct when the 15-day and monthly averaged precipitation and SST values were used. On the other hand, cold surges over the Sea of Japan primarily accounted for the amount of precipitation on the Sea of Japan side. The timing and strength of cold surges controlled precipitation on all timescales. We clearly found the impact of cold surges on SST on 15-day mean values, compared with the pentad mean values. To understand detailed impacts of SST on precipitation, including airsea interaction processes over the Sea of Japan, synoptic and shorter intraseasonal timescales should be examined in addition to seasonal or interannual timescales.
A sufficient condition for nonvanishing of determinants

In this note we derive sufficient conditions for a diagonally dominant reducible matrix to be nonsingular. 1. Throughout this note we are concerned with A=(aij), an nxn matrix which is diagonally dominant and where J = (i c N |laii laijl } 0 j=l;j:oi where N= {1, 2, * , n}. If J=N, A is strictly diagonally dominant and then the Gersgorin circle theorem implies that the determinant of A does not vanish [1, p. 106]. If A is irreducible, Taussky [5] has shown that A is nonsingular. In this note, we prove the following theorem. THEOREM. Let the matrix A be such thatfor each i 0 J there is a sequence of nonzero elements of A of the form ajil, ai12, i2 *, air; with j . J Then A is nonsingular. 2. We need the following lemma and results to prove the Theorem. LEMMA 1. Let A satisfy the conditions of the theorem. Then for any nonempty subset L of N such that L nrJ= 0, there is a nonzero element a with i E L andj 0 L. PROOF. Let L be a nonempty subset of N such that L rJ= 0 . Choose i1 E L, then i1 0 J and, hence, there is a sequence of nonzero elements of A of the form ai,2, ai2i3 . . * ai for some is E J. Let r be the first integer such that ir 0 L and note that 2< r<s since il E L and is 0 L. Then air1 $io with ir4. e L and ir 0 L. This proves Lemma 1. COROLLARY 2. Let A satisfy the conditions of the Theorem. If J= {il, i2, * * ik}, then there is a permutation (il i2 . i) of N such that, for eachj=k+1, * *, n, ai,i.00for some 1<j. Received by the editors February 22, 1973. AMS (MOS) subject classiflcations (1970). Primary 15A15; Secondary 15A15.
Plane wave diffraction by a wide slit in a thick impedance screen

A uniform asymptotic high-frequency solution is developed for the problem of diffraction of plane waves by a slit in an impedance screen of finite thickness. By using the Fourier transform technique the boundary-value problem is formulated into a pair of simultaneous modified Wiener-Hopf equations of the third kind which are decoupled and solved approximately. Several numerical results illustrating the effects of the surface impedances, slit width and slit thickness on the diffraction phenomenon are presented.
Population size vs. runtime of a simple EA

Evolutionary algorithms (EA) finds numerous applications, and practical knowledge on EAs is immense. In practice, sophisticated population-based EAs employing selection, mutation and crossover are applied. In contrast, theoretical analysis of EAs often concentrates on very simple algorithms like the (1+1) EA, where population size equals 1. In this paper, the question is addressed whether the use of a population by itself can be advantageous. A population-based EA does neither make use of crossover nor any diversity-maintaining operator is investigated on an example function. It is shown that an increase of the population size by polynomial factor decreases the expected runtime exponential to polynomial. Thereby, the so far best known gap is improved from superpolynomial to exponential. Moreover, it is proved that the stated runtime bounds occur with a probability exponentially close to one. Finally, a second example function is presented, where opposite results hold.
A large scale height galactic component of the diffuse 2-60 keV background

The diffuse 2-60 keV X-ray background has a galactic component clearly detectable by its strong variation with both galactic latitude and longitude. This galactic component is typically 10 percent of the extragalactic background toward the galactic center, half that strong toward the anticenter, and extrapolated to a few percent of the extragalactic background toward the galactic poles. It is acceptably modeled by a finite radius emission disk with a scale height of several kiloparsecs. The averaged galactic spectrum is best fitted by a thermal spectrum of kT about 9 keV, a spectrum much softer than the about 40 keV spectrum of the extragalactic component. The most likely source of this emission is low luminosity stars with large scale heights such as subdwarfs. Inverse Compton emission from GeV electrons on the microwave background contributes only a fraction of the galactic component unless the local cosmic ray electron spectrum and intensity are atypical.
Examination of large-scale structures in a turbulent plane mixing layer. Part 1. Proper orthogonal decomposition

Large-scale structures in a plane turbulent mixing layer are studied through the use of the proper orthogonal decomposition (POD). Extensive experimental measurements are obtained in a turbulent plane mixing layer by means of two cross-wire rakes aligned normal to the direction of the mean shear and perpendicular to the mean flow direction. The measurements are acquired well into the asymptotic region. From the measured velocities the two-point spectral tensor is calculated as a function of separation in the cross-stream direction and spanwise and streamwise wavenumbers. The continuity equation is then used for the calculation of the non-measured components of the tensor. The POD is applied using the cross-spectral tensor as its kernel. This decomposition yields an optimal basis set in the mean square sense. The energy contained in the POD modes converges rapidly with the first mode being dominant (49% of the turbulent kinetic energy). Examination of these modes shows that the first mode contains evidence of both known flow organizations in the mixing layer, i.e. quasi-two-dimensional spanwise structures and streamwise aligned vortices. Using the shot-noise theory the dominant mode of the POD is transformed back into physical space. This structure is also indicative of the known flow organizations.
Interpolative three-level block truncation coding algorithm

Zeng (see ibid., vol.27, p.1126-8, 1991) has described an interpolative two-level block truncation coding (BTC) image compression algorithm. The authors extend the work of Zeng to a three-level interpolative BTC algorithm. Compared to Zeng, the new algorithm gives reconstructed images with substantially higher image quality with no increase in bit rate.