Miracle-dz/UniFAR-FTUs huggingface dataset:
The finite-difference and finite-element modeling of seismic wave propagation and earthquake motion

Numerical modeling of seismic wave propagation and earthquake motion is an irreplaceable tool in investigation of the Earth’s structure, processes in the Earth, and particularly earthquake phenomena. Among various numerical methods, the finite-difference method is the dominant method in the modeling of earthquake motion. Moreover, it is becoming more important in the seismic exploration and structural modeling. At the same time we are convinced that the best time of the finite-difference method in seismology is in the future. This monograph provides tutorial and detailed introduction to the application of the finitedifference (FD), finite-element (FE), and hybrid FD-FE methods to the modeling of seismic wave propagation and earthquake motion. The text does not cover all topics and aspects of the methods. We focus on those to which we have contributed. We present alternative formulations of equation of motion for a smooth elastic continuum. We then develop alternative formulations for a canonical problem with a welded material interface and free surface. We continue with a model of an earthquake source. We complete the general theoretical introduction by a chapter on the constitutive laws for elastic and viscoelastic media, and brief review of strong formulations of the equation of motion. What follows is a block of chapters on the finite-difference and finite-element methods. We develop FD targets for the free surface and welded material interface. We then present various FD schemes for a smooth continuum, free surface, and welded interface. We focus on the staggered-grid and mainly optimally-accurate FD schemes. We also present alternative formulations of the FE method. We include the FD and FE implementations of the traction-at-split-nodes method for simulation of dynamic rupture propagation. The FD modeling is applied to the model of the deep sedimentary Grenoble basin, France. The FD and FE methods are combined in the hybrid FD-FE method. The hybrid method is then applied to two earthquake scenarios for the Grenoble basin. Except chapters 1, 3, 5, and 12, all chapters include new, previously unpublished material and results.
Nonlinear gyrokinetic equations for low-frequency electromagnetic waves in general plasma equilibria

A nonlinear gyrokinetic formalism for low‐frequency (less than the cyclotron frequency) microscopic electromagnetic perturbations in general magnetic field configurations is developed. The nonlinear equations thus derived are valid in the strong‐turbulence regime and contain effects due to finite Larmor radius, plasma inhomogeneities, and magnetic field geometries. The specific case of axisymmetric tokamaks is then considered and a model nonlinear equation is derived for electrostatic drift waves. Also, applying the formalism to the shear Alfven wave heating scheme, it is found that nonlinear ion Landau damping of kinetic shear‐Alfven waves is modified, both qualitatively and quantitatively, by the diamagnetic drift effects. In particular, wave energy is found to cascade in wavenumber instead of frequency.
Flux-Profile Relationships in the Atmospheric Surface Layer

Abstract Wind and temperature profiles for a wide range of stability conditions have been analyzed in the context of Monin-Obukhov similarity theory. Direct measurements of heat and momentum fluxes enabled determination of the Obukhov length L, a key independent variable in the steady-state, horizontally homogeneous, atmospheric surface layer. The free constants in several interpolation formulas can be adjusted to give excellent fits to the wind and temperature gradient data. The behavior of the gradients under neutral conditions is unusual, however, and indicates that von Karman's constant is ∼0.35, rather than 0.40 as usually assumed, and that the ratio of eddy diffusivities for heat and momentum at neutrality is ∼1.35, compared to the often-suggested value of 1.0. The gradient Richardson number, computed from the profiles, and the Obukhov stability parameter z/L, computed from the measured fluxes, are found to be related approximately linearly under unstable conditions. For stable conditions the Richar.
Did η Carinae's Weigelt Blobs Originate circa 1941?

We report astrometric measurements of η Carinae's Weigelt blobs C and D (also known as speckle objects C and D) derived from observations with the Hubble Space Telescope Wide Field Planetary Camera 2. Using three epochs of data with a temporal baseline of 5.9 yr, we measure blob D's proper motion relative to the central star to be 4.4 ± 1.4 mas yr-1, implying a date of origin of 1934.1. Similarly, using two epochs with a 1.7 yr baseline, we measure blob C's relative proper motion to be 3.8 ± 5.6 mas yr-1, indicating a probability of ejection after 1910 of ≈60%; we view this as confirming the more accurate blob D results (assuming coevality), with a combined post-1910 ejection indicated at a ≈90% confidence level. The blob D date roughly coincides with the sudden brightening of the central star observed in 1941 and provides a possible explanation for the onset of certain narrow spectral features, associated with the Weigelt blobs, that have been observed only since the mid-1940s. We propose that the ejection of Weigelt blobs C and D was related to this 1941 event.
Converging bounds for the free energy in certain statistical mechanical problems

We present sequences of converging upper and lower bounds to the partition function per spin specifically for a ferromagnetic Ising model which are valid in the entire finite, magnetic‐field, inverse‐temperature plane. They are based on the exact high‐temperature expansions for a finite system, properties of generalized Pade approximants, and the Villani limit theorem. The results depend only on the general structure of the partition function and certain monotonicity with system size properties which hold fairly generally.
Ultra-long-haul L-band WDM transmission over a standard single-mode fiber loop using DCF+CFBG hybrid dispersion compensation

We demonstrate a 10.7Gb/s-line-rate L-band WDM loop transmission over 1890km standard single-mode fiber (SSMF) with 100km amplifier spacing as well as non-return-to-zero (NRZ) format. For the first time, dispersion compensating fiber (DCF) plus chirped fiber Bragg grating (CFBG) is employed for hybrid inline dispersion compensation. The power penalty of each channel is less than 3dB after three loop transmission. The experimental results show that high-performance-CFBGs can be successfully used in ultra-long haul (>1000km) WDM systems. We also point out that all-CFBG compensation scheme is not suitable for re-circulating loop transmissions.
Conway's tiling groups

John Conway discovered a technique using infinite, finitely presented groups that in a number of interesting cases resolves the question of whether a region in the plane can be tessellated by given tiles. The idea is that the tiles can be interpreted as describing relators in a group, in such a way that the plane region can be tiled, only if the group element which describes the boundary of the region is the trivial element 1. A convenient way to describe the construction is by means of the Cayley graph or graph of a group. If G is a group, then its graph F(G) with respect to generators g1, g2 . , gn is a directed graph whose vertices are the elements of the group. For each vertex v E F(G), there will be n outgoing edges, labeled by the generators, and n incoming edges: the edge labeled gi connects v to vgi. It is convenient to make a slight modification of this picture when a generator gi has order 2. In that case, instead of drawing an arrow from v to vgi and another arrow from vgi back to v, we draw a single undirected edge labeled gi. Thus, in a drawing of the graph of a group, if there are any undirected edges, it is understood that the corresponding generator has order 2. The graph of a group is automatically homogeneous: for every element g E G, the transformation v -4 gv is an automorphism of the graph. Every automorphism of the labeled graph has this form. This property characterizes graphs of groups: a graph whose edges are labeled by a finite set F such that there is exactly one incoming and one outgoing edge with each label at each vertex is the graph of a group if and only if it admits an automorphism taking any vertex to any other. Whenever R is a relator for the group, that is, a word in the generators which represents 1, then if you start from v EF rand trace out R, you get back to v again. If G has presentation
One-dimensional photonic crystals in reflection geometry for optical applications

We investigate some properties of one-dimensional photonic band-gap materials that have the possibility of total internal reflection at one or more interfaces. The proposed structures have application for electro-optic modulation, sensing, and other optical devices. A specific example for electro-optic modulation is presented. Certain advantages of this arrangement may make it a desired geometry for specific applications like sensing.
Field Verification of the Relationship Between Entrainment Rate and Cumulus Cloud Diameter

Abstract This research is concerned with the verification of an expression which relates the entrainment rate in a cumulus cloud to the diameter of that cloud, where the entrainment rate is defined as the fractional increase in cloud mass due to mixing with the environment, per unit height. A series of airplane penetrations of relatively small cumulus clouds, conducted during the summer of 1971, was used as a data base for making Stommel entrainment calculations. When a stratification of 23 cloud passes was analyzed, a strong inverse diameter dependence on the mixing rate was evident. For six cloud passes that were described as vigorously growing, well-defined, single isolated towers, the inverse relation was even stronger, and could be expressed by E=0.3/R, where E is the entrainment rate and R the radius; the expression has a correlation coefficient of 0.85. There was a strong indication that the cumulus clouds studied were best described as the end result of an evolution of a series of starting plumes,.
PHOTOEXCITATIONS IN PARA-HEXAPHENYL

We investigate the absorption and emission of photoexcitations in polycrystalline hexaphenyl films. Transient and quasi-steady-state optical modulation spectroscopy is used to identify the photoexcited species and their time evolution. The observed photoinduced absorption spectrum can be assigned to at least three different species: (1) transitions between excited states ${(S}_{1}\ensuremath{\rightarrow}{S}_{n})$ and (2) transitions between triplet states ${(T}_{1}\ensuremath{\rightarrow}{T}_{n})$ which are formed by intersystem crossing from the singlet to the triplet regime in the 100 ps time domain. In addition we assign one peak to the (3) formation of aggregates in the oligomer films. The depopulation of the excited singlet states is responsible for both the dynamics of the initial photoinduced absorption and for stimulated emission. The stimulated emission found in the transient optical modulation spectroscopy shows a very limited spectral overlap with the photoinduced absorption. In contrast to doping experiments we find no evidence for long living polaronic states upon photoexcitation.
An inverse spectral result for the Neumann operator on planar domains

Abstract The Neumann operator is an operator on the boundary of a smooth manifold which maps the boundary value of a harmonic function to its normal derivative. In this paper, the Neumann operator on the boundary of smooth, bounded, simply connected planar domains is studied. The asymptotics of the eigenvalues are computed. The regularised zeta function for the Neumann operator at z = − 2 is computed. Study of the zeta function is then used to show that the unit disk is characterised by the spectrum of its Neumann operator.
The structure of tangential discontinuities: 1. Results of hybrid simulations

One-dimensional hybrid numerical simulations of tangential discontinuities (TDs) are presented for parameters representative of both the solar wind and magnetopause. For parameters common at the frontside magnetopause near local noon (antiparallel magnetic field and density gradients) it is found that TDs have a number of characteristic features that could be detected at the magnetopause. There is an overshoot in the magnetic field intensity on the low-density side of the TD. The overshoot is of the order of 20% for density ratios of 10 but can be somewhat larger for other parameters. It is found that the key parameters in determining TD structure are the density (and ion temperature) ratios, the plasma beta on the magnetosheath side, and the value of the electric potential difference across the TD. The relative orientation of the magnetic fields on either side of the TD does not appear to be of critical importance. For typical solar wind conditions (density and field gradients parallel) the magnetic field profile does not possess an overshoot but it does extend over 2-3 ion Larmor radii. The presence of a cross-field plasma flow is shown to slightly modify the magnetic field profile, but the velocity profile is very sensitive tomore » the sign of the flow (and hence the motional electric field). It is also shown that the TD structure is dependent on the assumed initial conditions. The currents in the TD layer can be a considerable fraction of the ion thermal speed, so that relaxation via plasma microinstabilities could arise. « less
New evidence for one-dimensional ordering in fast heavy ion beams

Experiments at the experimental storage ring with electron-cooled heavy ion beams have shown that at low beam intensity the beam enters a new regime. A transition to a state different from the normal gaseous state of the beam, which is determined by an equilibrium between intrabeam scattering and electron cooling, was made apparent by a sudden reduction of the momentum spread by up to one order of magnitude. Recently a destructive method to measure the horizontal beam size by beam scraping has been developed to a resolution of micrometres. Application of this method to the low intensity beam below the transition point has indicated a simultaneous reduction of the beam size by even more than an order of magnitude. A likely explanation is the formation of a one-dimensional ordered structure at low intensity. The stability of this ordered state against intrabeam scattering or other heating sources has been confirmed by direct observation of the beam in the low intensity regime after an intentional deactivation of cooling. The uncooled low intensity beam remains for millions of revolutions in the storage ring in the cold state, in contrast to beam intensities above the transition point for which an immediate heating is observed.
Symmetric informationally complete–positive operator valued measures and the extended Clifford group

We describe the structure of the extended Clifford group [defined to be the group consisting of all operators, unitary and antiunitary, which normalize the generalized Pauli group (or Weyl–Heisenberg group as it is often called)]. We also obtain a number of results concerning the structure of the Clifford group proper (i.e., the group consisting just of the unitary operators which normalize the generalized Pauli group). We then investigate the action of the extended Clifford group operators on symmetric informationally complete–positive operator valued measures (or SIC–POVMs) covariant relative to the action of the generalized Pauli group. We show that each of the fiducial vectors which has been constructed so far (including all the vectors constructed numerically by Renes et al.) is an eigenvector of one of a special class of order 3 Clifford unitaries. This suggests a strengthening of a conjecture of Zauner’s. We give a complete characterization of the orbits and stability groups in dimensions 2–7. Fina.
Observations of comet Kohoutek (1973f) with a ground-based Fabry-Perot spectrometer

Observations of H$alpha$, H$sub 2$O$sup +$, and O i emission lines from comet Kohoutek were made during a 2-month period around perihelion. Analyses of H$alpha$ line profiles and line intensities indicate that the mean outflow velocity of the hydrogen atoms was 7.8plus-or-minus0.2 km s$sup -1$ and that the hydrogen atom production rate typically varied from about 0.4times10$sup 29$ s$sup -1$ to about 1.4times10$sup 29$ s$sup -1$ for comet-Sun distances between 1 AU and 0.4 AU, respectively. The identification of an H$sub 2$O$sup +$ emission feature in certain H$alpha$ scans indicates that the H$sub 2$O$sup +$ ions were moving in a tailward direction with a velocity of 20 to 40 km s$sup -1$ with respect to the comet nucleus. An upper limit of 1 part in 100 was found for the D/H ratio in the cometary atomic hydrogen cloud. (AIP)
Static and dynamic magnetic properties of spherical magnetite nanoparticles

We present a detailed study of static and dynamic magnetic behavior of Fe3O4 nanoparticles with average particle sizes 〈d〉 ranging from 5 to 150 nm. Bulk-like properties such as saturation magnetization, hyperfine parameters, coercive field, and Verwey transition are observed in 150 nm particles. For decreasing particle size, the Verwey temperature, TV, shifts down to ∼20 K for 〈d〉=50 nm and is no longer observable for smaller particles. The smallest particles (〈d〉=5 nm) display superparamagnetic behavior at room temperature, with transition to a blocked state at TB∼45 K, which depends on the applied field. The existence of surface spin disorder can be inferred from the decrease of saturation magnetization MS at low temperatures, as the average particle size is reduced. This disordered surface did not show effects of exchange coupling to the particle core, as observed from hysteresis loops after field cooling in a 7 T magnetic field. For particles with 〈d〉=5 nm, dynamic ac susceptibility measurements show.
Investigations Into the Velocity and Distance Perception of Moving Sound Sources

Temporal loudness changes, binaural cues and Doppler shift can all influence distance perception of moving sound sources. This article will analyze different auditory distance perception cues of moving sound sources. In psychoacoustic experiments, the subjects were presented with dichotic and diotic stimuli of a set of real-life recordings taken from a passing passenger car and then asked to determine the velocity of the object and its minimal distance from the listener. The results of the listening experiments allow us to separate monaural distance perception cues from binaural ones, and thus show that binaural cues contribute significantly to the perception of velocity. For short distances and high velocities, the presentation of binaural cues causes a decrease in the perceived velocity while for long distances and low velocities this causes a clear increase. By estimating the minimal distance from the passing object, one observes a significant difference between dichotic and diotic presentation, which can be explained by an increased loudness of dichotic stimuli due to the binaural masking level difference (BMLD). Furthermore, it is shown that the main parameter for distance determination is the maximum sound pressure level at the listener's position. However, dynamic cues (change of sound pressure level over time, Doppler shift) are of considerable importance for the plausibility of the auditory scene.
Across-Wind Equivalent Static Wind Loads and Responses of Super-High-Rise Buildings

Using several formulas of across-wind aerodynamic forces and aerodynamic damping of rectangular super-high-rise buildings with side ratios smaller than 2 proposed previously by the authors, across-wind equivalent static loads and responses of super-high-rise buildings are evaluated through a proper combination of resonant and background components. The resonant component is computed according to the power spectral density of the base moment and the aerodynamic damping. The background component, whose vertical distribution is derived from background moment responses at different heights and then expressed as a cubic equation of the relative height, is computed using the base moment coefficients. Furthermore, comparisons are made for the equivalent static wind loads and responses of a hypothetical typical building between the present method and the AIJ (1996) method, which indicate the applicability of the present method. Finally, the effects of background component and aerodynamic damping on the equivalent wind loads and responses are also discussed.
Colour verbs in Modern Greek: A cognitive approach

This paper gives an outlook on how the coordination between phonology and semantics in verb derivation may look, and which constraints the distinction between possible/established, possible/novel, and not possible/forced verbs can be mapped onto. The object of investigation are the colour -izo verbs in Modern Greek. The analysis is mainly based on the studies by Berlin & Kay (1969), Kay & McDaniel (1978), and Kay & Maffi (1999) on basic colour terms. The colour verbs in Modern Greek are compared with the English colour verbs. It is shown that systematic gaps linked to the causative/inchoative paradigm of -izo verbs are due to the semantics of the base rather than deficiencies in the base's morphophonological character. The lower the evolutional stage that a base can be fitted to, the more likely an -izo derivative will be produced.
Ultrasonic measurement of internal temperature distribution

Implementation of advanced materials processing strategies are presently hampered by a lack of adequate process-control sensors. For the processing of basic materials, such as steel and aluminium, an internal temperature-distribution sensor is needed. For these metals, the velocity of ultrasound is well known to be a strong function of temperature. We have therefore explored the feasibility of precisely measuring the velocity-temperature relation for a particular steel grade and using this to convert an ultrasonic-velocity distribution (tomogram) for a hot steel body to an internal temperature distribution. To overcome the usual need in conventional tomography for many thousands of path-integral measurements along intersecting ray paths, a priori heat-flow information has been incorporated into the reconstruction algorithms. As a result, for uniformly cooling bodies with the simple geometries usually encountered (e.g. circular, square or rectangular cross sections), the number of measurements can be reduced from many thousands to as few as three to five. Initial experiments on austenitic steel samples of cylindrical and square cross section by using non-contact ultrasonic techniques have shown that this approach yields acceptable temperature profiles at temperatures of up to 750 °C.
ON A CONJECTURE OF S. BERNSTEIN IN APPROXIMATION THEORY

With denoting the error of best uniform approximation to by polynomials of degree at most on the interval , the famous Russian mathematician S. Bernstein in 1914 established the existence of a positive constant for which Moreover, by means of numerical calculations, Bernstein determined, in the same paper, the following upper and lower bounds for : Now, the average of these bounds is 0.282, which, as Bernstein noted as a "curious coincidence," is very close to . This observation has over the years become known as the Bernstein Conjecture: Is ? We show here that the Bernstein conjecture is false. In addition, we determine rigorous upper and lower bounds for , and by means of the Richardson extrapolation procedure, estimate to approximately 50 decimal places.Tables: 4. Figures: 1. Bibliography: 12 titles.