Miracle-dz/UniFAR-FTUs huggingface dataset:
Infinite Histories and Steady Orbits in Repeated Games

We study a model of repeated games with the following features: (a) Infinite histories. The game has been played since days of yore, or is so perceived by the players: (b) Turing machines with memory. Since regular Turing machines coincide with bounded recall strategies (in the presence of infinite histories), we endow them with "external" memory; (c) Nonstrategic players. The players ignore complicated strategic considerations and speculations about them. Instead, each player uses his/her machine to update some statistics regarding the others′ behaviour, and chooses a best response to observed behaviour. Relying on these assumptions, we define a solution concept for the one shot game, called steady orbit. The (closure of the) set of steady orbit payoffs strictly includes the convex hull of the Nash equilibria payoffs and is strictly included in the correlated equilibria payoffs. Assumptions (a)-(c) above are independent to a large extent. In particular, one may define steady orbits without explicitly dealing with histories or machines.
Influence of mean loading on noise generated by the interaction of gusts with a cascade: downstream radiation

We consider the effects of blade mean loading on the noise generated by the interaction between convected vorticity and a blade row. The blades are treated as flat plates aligned at a non-zero incidence angle, $\delta$, to the oncoming stream, and we take harmonic components of the incident vorticity field with reduced frequency $k$, and use asymptotic analysis in the realistic limit $k\,{\gg}\, 1$, $\delta \,{\ll}\, 1$ with $k\delta=O(1)$. In a previous paper (Peake & Kerschen, J. Fluid Mech., vol. 347 (1997), pp. 315–346) we have analysed the sound radiated back upstream, but the field in the blade passages and the sound radiated downstream are also of considerable practical interest, and are considered in this paper. The flow is seen to consist of inner regions around each leading edge, in which sound is generated by the local gust–airfoil and gust–flow interactions, and an outer region in which the incident gust and the acoustic radiation interact with the non-uniform mean flow and the other blades. It is shown that the complicated multiple interactions between the blades can be represented by images in potential–streamfunction space, yielding closed-form expressions for the phase distortion experienced by sound waves propagating down the blade passages. The acoustic radiation downstream of the cascade at $O(1)$ distances is dominated by the duct-mode beams that emanate from the passages, while the far downstream field is generated by the diffraction of the duct modes by the trailing edges. The modal amplitudes of the radiation field far downstream tend to be largest when the mode direction is close to the propagation direction of the duct mode which generated it, corresponding to the way (in uniform flow) in which the radiation from a single blade passage tends to be beamed in the duct-mode directions. Although the diffraction coefficient for the scattering from a single trailing edge is singular in these directions, we show how uniformly valid expressions can be derived by combining the trailing-edge fields in an appropriate way, thereby describing the larger amplitude in the beam directions. The steady non-uniform flow downstream has the effect of tilting the directions of the beams by $O(\delta)$ angles away from the duct-mode directions, which are explicitly determined. Throughout this analysis it will be seen that the interaction with the non-uniform mean flow introduces phase corrections of size $O(k\delta)$, which, given the way in which interference effects between the multiple blades dominate unsteady cascade flow, proves to be highly significant.
XVIII. Radioactivity and Earth Movements

I. —TECTONIC HYPOTHESES. Both external and internal geological processes are controlled by gravity and the earth's bodily movements. The circulations of matter which constitute the external processes are maintained by energy derived from the sun, whereas the internal processes derive much of their energy from the earth's internal heat, the latter being partly an inheritance, and partly an income supplied by atomic disintegration. Hypotheses relating to the physical causes of earth movements must take all the relevant factors into consideration as fully as the data permit. At present there is a plethora of hypotheses in the field, some of which are mutually contradictory. Much of this confusion is a result of lack of data, and is temporarily unavoidable; on the other hand a good deal is unnecessary, and has been introduced by exaggerating the effects of certain factors while ignoring those of others. The most remarkable example of a neglected source of geological energy is the heat generated by the radioactive elements. Outside the British Isles there has been little recognition of the importance of this factor, and it is therefore hardly a matter for surprise that hypotheses in which it is ignored should prove to be inadequate. Among the forces to which appeal has been made are the following (21):— Gravitational: Cosmic Stresses set up by (a) Tides due to the sun and moon. (b) Precession of the equinoxes. Terrestrial (c) Attraction between continents. (d) Pohlflucht force. Stresses set This 250-word extract was created in the absence of an abstract
Cloud Condensation Nuclei from Industrial Sources and Their Apparent Influence on Precipitation in Washington State

Abstract Measurements of the concentrations of cloud condensation nuclei (CCN) in the air in Washington State have shown that pulp and paper mills, and certain other industries, are prolific sources of CCN. The rate of production of CCN from large paper mills can be as high as 1019 sec−1. Direct observations show that clouds often form downwind of these mills and, in some cases, these clouds produce precipitable particles very efficiently. A comparison of precipitation and streamflow records in Washington for the period 1929–46 with those for 1947–66 shows that a number of areas have had a mean annual precipitation during the second period more than 30% greater than that in the first period. In nearly all cases these areas are in the vicinity of large industrial sources of CCN and it is suggested that the higher precipitation in recent years is a consequence of the increased numbers of very efficient CCN emitted into the atmosphere by these sources.
Coupled lattice Boltzmann method and discrete element modelling of particle transport in turbulent fluid flows: Computational issues

This paper presents essential numerical procedures in the context of the coupled lattice Boltzmann (LB) and discrete element (DE) solution strategy for the simulation of particle transport in turbulent fluid flows. Key computational issues involved are (1) the standard LB formulation for the solution of incompressible fluid flows, (2) the incorporation of large eddy simulation (LES)‐based turbulence models in the LB equations for turbulent flows, (3) the computation of hydrodynamic interaction forces of the fluid and moving particles; and (4) the DE modelling of the interaction between solid particles. A complete list is provided for the conversion of relevant physical variables to lattice units to facilitate the understanding and implementation of the coupled methodology. Additional contributions made in this work include the application of the Smagorinsky turbulence model to moving particles and the proposal of a subcycling time integration scheme for the DE modelling to ensure an overall stable solution. A particle transport problem comprising 70 large particles and high Reynolds number (around 56 000) is provided to demonstrate the capability of the presented coupling strategy. Copyright © 2007 John Wiley & Sons, Ltd.
On the stability of the decelerating laminar boundary layer

The stability of a decelerating boundary-layer flow is investigated experimentally and numerically. Experimentally, a flat plate having a Blasius boundary layer is decelerated in an 18 m towing tank. The boundary layer becomes unstable to two-dimensional waves, which break down into three-dimensional patterns, hairpin vortices, and finally turbulent bursts when the vortices lift off the wall. The unsteady boundary-layer equations are solved numerically to generate instantaneous velocity profiles for a range of boundary and initial conditions. A quasi-steady approximation is invoked and the stability of local velocity profiles is determined by solving the Orr–Sommerfeld equation using Chebyshev matrix methods. Comparisons are made between the numerical predictions and the experimentally observed instabilities.
Pulsed thermal emission from the accreting pulsar XMMU J054134.7-682550

Aims. Soft X-ray excesses have been detected in several Be/X-ray binaries and interpreted as the signature of hard X-ray reprocessing in the inner accretion disk. The system XMMU J054134.7-682550, located in the LMC, featured a giant Type II outburst in August 2007. The geometry of this system can be understood by studying the response of the soft excess emission to the hard X-ray pulses. Methods. We have analyzed series of simultaneous observations obtained with XMM-Newton/EPIC-MOS and RXTE/PCA in order to derive spectral and temporal characteristics of the system, before, during and after the giant outburst. Spectral fits were performed and a timing analysis has been carried out. Spectral variability, spin period evolution and energy dependent pulse shapes are analysed. Results. The outburst (LX = 3 × 10 38 erg/s ≈ LEDD) spectrum could be modeled successfully using a cutoff powerlaw, a cold disk emission, a hot blackbody, and a cyclotron absorption line. The magnetic field and magnetospheric radius could be constrained. The thickness of the inner accretion disk is broadened to a width of 75 km. The hot blackbody component features sinusoidal modulations indicating that the bulk of the hard X-ray emission is emitted preferentially along the magnetic equator. The spin period of the pulsar decreased very significantly during the outburst. This is consistent with a variety of neutron star equations of state and indicates a very high accretion rate.
An Illustrative Model of Seasonal and Interannual Variations of the Stratospheric Circulation

Abstract A simple wave-zonal flow interaction model, originally developed by Holton and Mass, is used to illustrate a rudimentary conception of seasonal and interannual variations of the stratospheric circulation. The radiative heating is varied periodically with an annual component to investigate the response of the circulation (i.e., the seasonal variation) to the periodic forcing. The response is qualitatively different depending on the wave forcing from the troposphere. The difference resembles that of the climatological seasonal march between the Northern and the Southern hemispheres. No example of interannual variations (namely, nonperiodic responses) was obtained for the periodic annual forcing. Interannual variation of external conditions is necessary in the present model to obtain interannual variations. A finite range of year-to-year variations of the wave forcing can produce large interannual variability as in the Northern Hemisphere.
Periodic orbits of nonlinear relative dynamics along an eccentric orbit

This paper is concerned with formation acquisition and reconfiguration problems with an eccentric reference orbit. As a first step, the characterization problem is considered for all initial conditions that constitute periodic solutions of the nonlinear equations of relative motion. Under the condition that the inertial orbits of the leader and a follower are coplanar, initial conditions of all periodic relative orbits are generated in terms of parameters of their orbits and their initial positions. Then the inertial orbit of the follower is rotated successively around the two axes of its perifocal reference system, and the initial conditions of all noncoplanar relative orbits are derived. Based on these periodic relative orbits, formation acquisition and reconfiguration problems by a feedback controller are formulated. The main performance index of a feedback controller is the total velocity change during the operation. Using the property of null controllability with vanishing energy of the Tschauner-Hempel equations, suboptimal controllers are designed via the differential Riccati equation of the linear regulator theory of periodic systems.
Dip Spectroscopy of the Low-Mass X-Ray Binary XB 1254–690

We observed the low-mass X-ray binary XB 1254-690 with the Rossi X-Ray Timing Explorer in 2001 May and December. During the first observation, strong dipping on the 3.9 hr orbital period and a high degree of variability were observed, along with "shoulders" ~15% deep during extended intervals on each side of the main dips. The first observation also included pronounced flaring activity. The nondip spectrum obtained using the PCA instrument was well described by a two-component model consisting of a blackbody with kT = 1.30 ± 0.10 keV plus a cutoff power-law representation of Comptonized emission with power-law photon index 1.10 ± 0.46 and a cutoff energy of 5.9 keV. The intensity decrease in the shoulders of dipping is energy-independent, consistent with electron scattering in the outer ionized regions of the absorber. In deep dipping, the depth of dipping reached 100% in the energy band below 5 keV, indicating that all emitting regions were covered by absorber. Intensity-selected dip spectra were well fitted by a model in which the pointlike blackbody is rapidly covered, while the extended Comptonized emission is progressively overlapped by the absorber, with the covering fraction rising to 95% in the deepest portion of the dip. The intensity of this component in the dip spectra could be modeled by a combination of electron scattering and photoelectric absorption. Dipping did not occur during the 2001 December observation, but remarkably, both bursting and flaring were observed contemporaneously.
Mathematical Model of Major Hysteresis Loop and Transient Magnetizations

Abstract In this article, a new mathematical model of a major hysteresis loop and a simple procedure for the formation of first-order and higher-order reversal curves are proposed. The applicability of the model has been tested by comparison with measured results, obtained with electrical steel and ferrite cores, and simulation results obtained with the Preisach model. Very good agreement has been found between simulated and measured major and minor hysteresis loops, as well as first-order and higher-order reversal curves.
Drag on a sphere moving horizontally in a stratified fluid

The steady translational motion of a sphere in a Boussinesq stratified fluid, where the motion is parallel to the stratification surfaces, is studied. A model based on existing linear gravity wave theory for large Froude numbers and on new theory for small Froude numbers is presented. The small-Froude-number theory describes wave generation and the presence of a rectangular-section attached wake whose size and shape is controlled by the size and shape of the wave generation regions. Existing laboratory data are used to evaluate the model's prediction for the drag coefficient of the sphere as a function of Froude number.
Application of Landau-Lifshitz-Bloch dynamics to grain switching in heat-assisted magnetic recording

Magnetization dynamics in heat-assisted magnetic recording (HAMR) involves magnetization collapse and re-formation under rapid local temperature excursion in a temporally varying applied magnetic field, with temperature likely moving above and below the medium Curie point on nanosecond timescales. Traditional micromagnetic simulation of the writing process in magnetic data storage has been restricted to isothermal processes in which macrospin magnetization dynamics are handled with the well-established Landau-Lifshitz-Gilbert (LLG) algorithm or close variants. Classical LLG treats the magnitude of material magnetization M as fixed (at zero Kelvin), so initial attempts at micromagnetic analysis of HAMR have typically dealt with the effects of temperature variation in HAMR in a somewhat ad hoc manner (e.g., insertion of M(T), A(T), K(T)), and have not been rigorous. A much improved treatment of this problem substitutes the Landau-Lifshitz-Bloch (LLB) algorithm in which thermally driven magnetization variati.
Experimental study of internal conical refraction in a biaxial crystal with Laguerre–Gauss light beams

The effect of internal conical refraction (CR) in a biaxial crystal was studied using Laguerre–Gauss light beams LG 0 ℓ ? > with ℓ = 1 ? > and 2, while the lowest-order LG 0 0 ? > beam was used as a reference. The transition from ordinary double refraction to CR was examined. It has been shown that double refraction of an LG 0 ℓ ? > beam forms two focal spots containing ℓ ? > dark stripes. These stripes evolve into ℓ + 1 ? > dark rings over an annular focal image when CR is established, and it results in a fine-structure of ℓ + 2 ? > bright focal rings with different intensities. In a sharp contrast to the lowest-order reference, the multiring focal structure has a distinct asymmetry with respect to the focal image plane. It has been shown that bright off-axis ‘hot spot’ can be formed on the far-field profiles of outgoing light beams when the biaxial crystal is slightly tilted, and a small angle between the propagation axis of the beam and the optic axis of the crystal arises. These off-axis light structures emerge as either a charge-one optical vortex or a zero-charge spot with annihilated vorticity. Polarization selection reveals J 1 ? > or J 0 ? > Bessel-like profiles of the corresponding ‘hot spots’, and a complex pattern of forked fringes in the dark region near the beam core.
Microstructures of rapidly-heated/quenched and transformed Nb/sub 3/Al multifilamentary superconducting wires

Microstructures of rapidly-heated/quenched and transformed Nb/sub 3/Al multifilamentary wires were studied by using transmission electron microscopy. Nb/Al composite wires are fabricated by a jelly-roll process. The Nb/Al composite filaments changed into an Nb-Al supersaturated bcc solid solution with rapid-heating/quenching. The Nb-Al bcc phase consists of many crystal grains with diameters of 2-4 /spl mu/m, surrounded with large-angle grain boundaries. Some spherical voids, about 0.1 micron in diameter, were also observed at the intra- and intergrains. All grain boundaries of the Nb-Al bcc phases are simple flat planes. Then, the Nb-Al bcc phases were transformed into A15 phases (grain size: 0.5-2.0 /spl mu/m in diameter) with additional annealing. Secondary phases were not observed in the A15 filaments. Grain boundaries of the A15 phases show zig-zag shape unlike those of the Nb-Al bcc phases, and every grain of A15 phases is an aggregation of sub-grains of 80-150 nm in diameter. Sub-grain boundaries are small-angle ones. Moreover we found that many stacking faults formed in the A15 sub-grains in parallel with spaces of 10-20 nm. These numerous plane defects seem to be the main pinning centers in the rapidly-heated/quenched and transformed Nb/sub 3/Al wires.
On steady rotational high speed flows: the compressible Taylor–Culick profile

We consider the compressible flow analogue of the well-known Taylor–Culick profile. We first present the compressible Euler equations for steady, axisymmetric, isentropic flow assuming uniform injection of a calorically perfect gas in a porous chamber. We then apply the Rayleigh–Janzen expansion in powers of , where Mw is the wall Mach number. We solve the ensuing equations to the order of and apply the results up to the sonic point in a nozzleless chamber. Area averaging is also performed to reconcile with one-dimensional theory. Our solution agrees with the existing theory to the extent that it faithfully captures the steepening of the Taylor–Culick profile with downstream movement. Based on the closed-form expressions that we obtain, the main flow attributes are quantified parametrically and compared to the existing incompressible and quasi-one-dimensional theories. Verification by computational fluid dynamics is also undertaken. Comparison with two turbulent flow models shows excellent agreement, particularly in retracing the streamwise evolution of the velocity. Regardless of the Mach number, we observe nearly identical trends in chambers that are rescaled by the (critical) sonic length, Ls. Using a suitable transformation, we prove the attendant similarity and provide universal criteria that can be used to assess the relative importance of gas compression in solid rocket motors. Owing to sharper velocity gradients at the wall, we find that an incompressible model underestimates the skin friction along the wall and underpredicts the centreline speed by as much as 13% at the sonic point. In practice, such deviations become appreciable at high-injection rates or chamber aspect ratios.
ATMOSPHERIC WATER VAPOR TRANSPORT AND THE WATER BALANCE OF NORTH AMERICA: PART I. CHARACTERISTICS OF THE WATER VAPOR FLUX FIELD

Abstract The atmospheric water vapor flux over North America and the Central American Sea (Gulf of Mexico and Caribbean Sea) has been investigated for the period May 1, 1961–April 30, 1963, as part of a more general study of the water balance of these areas. Mean monthly values of the total vapor flux components are analyzed and the more important aspects of the regional vapor flux climatology are discussed and illustrated by maps and cross-sections. Additional insight into the seasonal march is obtained from the computation of the total monthly vapor flux across selected regional boundaries. Major features of the North American total vapor flux field previously described by Benton and Estoque are confirmed, but the more extensive data used in this study bring out additional significant detail, particularly over the southern United States. Important diurnal variations are found in the flux field, particularly during the summer south of 50° N. These result primarily from diurnal variations in the average m.
Collisional stochastic ripple diffusion of alpha particles and beam ions on TFTR

Predictions for ripple loss of fast ions from TFTR are investigated with a guiding centre code including both collisional and ripple effects. A synergistic enhancement of fast ion diffusion is found for toroidal field ripple with collisions. The total loss is calculated to be roughly twice the sum of ripple and collisional losses calculated separately. Discrepancies between measurements and calculations of plasma beta at low current and large major radius are resolved when both effects are included for neutral beam ions. A 20 to 30% reduction in alpha particle heating is predicted for qa=6-14, R=2.6 m DT plasmas on TFTR owing to first orbit and collisional stochastic ripple diffusion
Cluster Correlations from N-Point Correlation Amplitudes

It is shown, by using a new technique, how the much-debated cluster correlation function is directly related to the higher order galaxy correlations. Mathematical techniques are adopted from biased galaxy formation: here the biasing simulates the detection of the clusters, rather than their dynamical formation. A simple, analytical example is given. As a practical application of our simplified model, a novel method to determine the amplitudes of the irreducible N-point correlation functions in the gravitational clustering hierarchy is also presented. The corrected Lick catalog is used to obtain values of q N up to N = 8, considerably beyond previous attempts