Miracle-dz/UniFAR-FTUs huggingface dataset:
Three‐dimensional numerical analysis of steady state pumping tests in heterogeneous confined aquifers

We study three‐dimensional steady state flow field generated by a fully penetrating well extracting a constant water discharge from a confined aquifer of constant thickness. The hydraulic conductivity K is modeled as an axisymmetric, stationary random space function, and the flow equation is solved by using the seven‐node finite volume numerical scheme. In view of application in aquifer characterization we analyze how the equivalent conductivity Keq varies as a function of the distance from the extraction well. The numerical simulations showed that the boundary condition at the well exerts a large impact on Keq and that the first‐order solution in σY2 obtained by Indelman et al. (1996) is valid up to σY2 = 0.5. For higher values of σY2 the first‐order solution overestimates Keq with differences that for a given σY2, reduce progressively as the formation becomes more anisotropic. A simple inverse procedure based on Keq, obtained through cross‐well interference, is finally proposed and tested with the objective of estimating the parameters of the geostatistical model of variability of the hydraulic conductivity. A few parametric examples showed that a suitable interpretation of pumping tests can be used to safely estimate parameters such as the geometric mean of the hydraulic conductivity, its variance, and, although with larger uncertainty, the horizontal integral scale, while the inference of the anisotropy ratio is highly uncertain and error prone.
Sensitivity analysis of statistical measure for the reconstruction of microstructures based on the minimization of generalized least-square functionals

For the simulation of micro-heterogeneous materials the FE2-method provides incorporation of the mechanical behavior at the microscale in a direct manner by taking into account a microscopic boundary value problem based on a representative volume element (RVE). A main problem of this approach is the high computational cost, when we have to deal with RVEs that are characterized by a complex geometry of the individual constituents. This leads to a large number of degrees of freedom and history variables at the microscale which needs a large amount of memory, not to mention the high computation time. Therefore, methods that reduce the complexity of such RVEs play an important role for efficient direct micro-macro transition procedures. In this contribution we focus on random matrix-inclusion microstructures and analyze several statistical measures with respect to their influence on the characterization of the inclusion phase morphology. For this purpose we apply the method proposed in Balzani and Schr¨oder (2008); Balzani et al. (2009a), where an objective function is minimized which takes into account differences between statistical measures computed for the original binary image of a given real microstructure and a simplified statistically similar representative volume element (SSRVE). The analysis with respect to the capability of the resulting SSRVEs to reflect the mechanical response in some simple independent virtual experiments allows for an estimation of the importance of the investigated statistical measures.
Modeling CME‐shock‐driven storms in 2012–2013: MHD test particle simulations

The Van Allen Probes spacecraft have provided detailed observations of the energetic particles and fields environment for coronal mass ejection (CME)‐shock‐driven storms in 2012 to 2013 which have now been modeled with MHD test particle simulations. The Van Allen Probes orbital plane longitude moved from the dawn sector in 2012 to near midnight and prenoon for equinoctial storms of 2013, providing particularly good measurements of the inductive electric field response to magnetopause compression for the 8 October 2013 CME‐shock‐driven storm. An abrupt decrease in the outer boundary of outer zone electrons coincided with inward motion of the magnetopause for both 17 March and 8 October 2013 storms, as was the case for storms shortly after launch. Modeling magnetopause dropout events in 2013 with electric field diagnostics that were not available for storms immediately following launch have improved our understanding of the complex role that ULF waves play in radial transport during such events.
Resampling Methods for Dependent Data

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Analysis of the Urbach tails in absorption spectra of undoped ZnO thin films

We report the analysis of the Urbach effect in the absorption spectra of the undoped ZnO thin films. The absorption coefficients of the ZnO thin films show the exponential rise, also known as the Urbach tails, just below the free exciton peak. Fitting of the steepness parameter of the Urbach tails yields the phonon energy to be ℏωp=76 ± 4 meV, consistent with ℏωp=72 meV measured from the photoluminescence spectra of ZnO. The temperature dependence of the Urbach energy, the steepness parameter, and the energy gap strongly suggests that the observed Urbach effect is a result of the cumulative effect of impurities, structural disorders, and electron-phonon interaction in the absorption processes.
Can surface magnetic fields reproduce solar irradiance variations in cycles 22 and 23

Total solar irradiance is reconstructed using data from the spectromagnetograph on Kitt Peak for 1992-2003 (cov- ering parts of cycles 22 and 23) and compared with observational data. The model assumes that solar irradiance variations are caused by surface magnetism and its single free parameter is kept at the same value for both cycles. A good correspondence is found for the whole period of time, with no bias between the two cycles on time-scales longer than the solar rotation period. This is in agreement with the recent results of de Toma et al. (2004), but it is in contrast to the earlier analysis of de Toma et al. (2001), and suggests that the source of the irradiance variations is the same for cycles 22 and 23, namely the evolution of the magnetic flux at the solar surface.
FLOW OF A FLUID BETWEEN TWO ROTAToING COAXIAL CONES HAVING THE SAME VERTEX

In this paper the secondary flows between two rotating coaxial cones (also the cone-plate arrangement as a particular case) of a non-Newtonian fluid with the inclusion of inertia terms according to Oseen's scheme have been investigated. Effects of cross-viscosity and visco-elasticity have been treated as small. It has been found that in the case of a Newtonian fluid the fluid particles in the secondary flow move away from the vertex almost parallel to the inner cone which is taken to rotate faster than the other cone, and the fluid particles nearer the outer cone move almost parallel to it towards the vertex. In the case of non-Newtonian fluids the secondary flow field is divided into two parts. The stream lines in the inner domain are closed loops, while in the outer domain they resemble the flow pattern of the Newtonian fluid. The effect of cross-viscosity and visco-elasticity on the stresses exerted by the fluid on the surfaces has been evaluated.
Widely tunable single-mode quantum cascade laser source for mid-infrared spectroscopy

We demonstrate a compact, single-mode quantum cascade laser source continuously tunable between 8.7 and 9. 4μm. The source consists of an array of single-mode distributed feedback quantum cascade lasers with closely spaced emission wavelengths fabricated monolithically on a single chip and driven by a microelectronic controller. Our source is suitable for a variety of chemical sensing applications. Here, we use it to perform absorption spectroscopy of fluids.
Reddening and polarimetric studies toward IC 1805

Near IR and (V-I) photometry is presented for probable members in the cluster IC 1805. From a color-difference analysis, the ratio of total to selective absorption R(v), is found to be uniform across the cluster and calculated to be 3.1 + or - 0.1. Assuming a distance modulus to the Hyades of 3.3 mag, a distance to IC 1805 of 2.4 + or - 0.1 kpc is obtained by employing several ZAMS fitting calibrations. The resultant C-M diagram contains both MS and ZAMS B type stars, implying that massive star formation in the cluster was a continuous process. Photometric and spectroscopic data for foreground stars toward the cluster indicate that at least two-thirds of the reddening of the cluster is due to the general interstellar material (IM). Multicolor polarimetric measurements are also presented for 24 probable cluster members and for 49 foreground objects. It is concluded that the visual polarization across the local galactic spiral arm is 5 percent, and that the size distribution of grains within IC 1805 is similar to that in the foreground region. After correcting for foreground IM, the residual intracluster polarization indicates that the cluster may be located near a Parker (1966) magnetic well withmore » field strength similar to that of the foreground IM. 85 refs.« less
Global existence and blow‐up of solutions for nonlinear viscoelastic wave equation with degenerate damping and source

In this paper we investigate the global existence and finite time blow‐up of solutions to the nonlinear viscoelastic equation \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$$ u_{tt}-\triangle u+\int _0^t g(t-s)\triangle u(s)\,\mathrm{d} s+|u|^k\partial j(u_t)=|u|^{p-1}u \quad {\rm in}\quad \Omega \times (0, T) $$\end{document} associated with initial and Dirichlet boundary conditions. Here ∂j denote the sub‐differential of j. Under suitable assumptions on g(·), j(·) and the parameters in the equation, we obtain the global existence of generalized solutions, weak solutions for the equation. The finite time blow‐up of weak solutions for the equation is also established provided the initial energy is negative and the exponent p is greater than the critical value k + m. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Stable isotopes in precipitation

In chapter 2 the isotopic fractionation of water in some simple condensation-evaporation processes are considered quantitatively on the basis of the fractionation factors given in section 1.2. The condensation temperature is an important parameter, which has got some glaciological applications. The temperature effect (the δ's decreasing with temperature) together with varying evaporation and exchange appear in the “amount effect” as high δ's in sparse rain. The relative deuterium-oxygen-18 fractionation is not quite simple. If the relative deviations from the standard water (S.M.O.W.) are called δ D and δ 18 , the best linear approximation is δ D = 8 δ 18 . Chapter 3 gives some qualitative considerations on non-equilibrium (fast) processes. Kinetic effects have heavy bearings upon the effective fractionation factors. Such effects have only been demonstrated clearly in evaporation processes, but may also influence condensation processes. The quantity d = δ D −8 δ 18 is used as an index for non-equilibrium conditions. The stable isotope data from the world wide I.A. E.A. -W.M. O. precipitation survey are discussed in chapter 4. The unweighted mean annual composition of rain at tropical island stations fits the line δ D = 4.6 δ 18 indicating a first stage equilibrium condensation from vapour evaporated in a non-equilibrium process. Regional characteristics appear in the weighted means. The Northern hemisphere continental stations, except African and Near East, fit the line δ D = 8.0 δ 18 + 10 as far as the weighted means are concerned (δ D = 8.1 δ 18 + 11 for the unweighted) corresponding to an equilibrium Rayleigh condensation from vapour, evaporated in a non-equilibrium process from S.M. O.W. The departure from equilibrium vapour seems even higher in the rest of the investigated part of the world. At most stations the δ D and varies linearily with δ 18 with a slope close to 8, only at two stations higher than 8, at several lower than 8 (mainly connected with relatively dry climates). Considerable variations in the isotopic composition of monthly precipitation occur at most stations. At low latitudes the amount effect accounts for the variations, whereas seasonal variation at high latitudes is ascribed to the temperature effect. Tokyo is an example of a mid latitude station influenced by both effects. Some possible hydrological applications are outlined in chapter 5. DOI: 10.1111/j.2153-3490.1964. tb00181.x
Study of the superfluid transition in two-dimensional /sup 4/He films

We have studied the superfluid transition of thin two-dimensional /sup 4/He films adsorbed on an oscillating substrate. The superfluid mass and dissipation support the Kosterlitz-Thouless picture of the phase transition in a two-dimensional superfluid. In addition we observe finite-velocity effects which are not explained by current dynamic theories. We also report data on 2D /sup 3/He-/sup 4/He mixtures.
Inverse Neumann obstacle problem

Results are reported for direct and inverse scattering of plane acoustic waves from sound-hard scatterers of arbitrary shapes in an infinite, homogeneous ambience. The direct problem is solved via a shape deformation technique which is valid for finite deformations. The resulting solution requires solving only a set of algebraic recursion relations, but neither integral equations nor Green’s function. The methodology has three essential features: all calculations refer exclusively to a known simple boundary Γs instead of the iteratively updated scatterer shapes; the Jacobian of the scattered field is evaluated by solving a series of Helmholtz’s equations (with different boundary data) in the region exterior to the simple shape Γs; and no ambiguity in the solution arises due to the interior eigenvalues. The inverse problem of recovering the scatterer boundary shape is solved by least square minimization using the Levenberg–Marquardt algorithm. Inversions of several two-dimensional shapes with varying degre.
Formation and coarsening of sponge-like Si-SiO2 nanocomposites

It has been recently found by energy filtered transmission electron microscopy (EFTEM) that metastable SiOx≈1 films decay into a Si nanowire network embedded in SiO2 by spinodal decomposition during thermal treatment. To have a guideline for nanocomposites fabrication, details of the morphology evolution have been studied by comparison of EFTEM images with kinetic Monte-Carlo (kMC) simulations. Pair correlation functions calculated by kMC have been adjusted to that extracted from EFTEM. This comparison leads to the conclusion about characteristic lengths of 3D morphologies. Combining kMC with EFTEM delivers the understanding for tailoring the properties like quantum confinement of the spongy Si.
Solar limb brightening at 1. 3 millimeters

Radial scans across the solar disk with the 28'' half-power beam width of the Owens Valley Radio Observatory 10 m telescope provide evidence for 10% +- 5% limb brightening in the mean quiet Sun at 1.3 mm. This result is consistent with a spherically symmetric chromosphere. The solar radius at 1.3 mm was 8. ''6 +- 1'' larger than the optical radius, which is consistent with the expected effect of a forest of optically thick spicules viewed at the extreme limb.
Preservers of completely positive matrix rank

Let denote the set of matrices with entries in . We write to denote the subset of , all of whose entries are non-negative. Let denote the set of all real symmetric matrices. A matrix is said to be completely positive if there is some matrix such that . The CP-rank of the matrix is the smallest such that for some . In this article, we shall investigate the linear operators on that preserve sets of matrices defined by the CP-rank. We classify those that preserve the CP-rank function, those that preserve the set of CP-rank-1 matrices, those that preserve the sets of CP-rank-1 matrices and the set of CP-rank-2 matrices, and those that strongly preserve the set of CP-rank-1 matrices.
Temperature dependent optical properties of (002) oriented ZnO thin film using surface plasmon resonance

Temperature dependent optical properties of c-axis oriented ZnO thin film were investigated using surface plasmon resonance (SPR) technique. SPR data for double layer (prism-Au-ZnO-air) and single layer (prism-Au-air) systems were taken over a temperature range (300–525 K). Dielectric constant at optical frequency and real part of refractive index of the ZnO film shows an increase with temperature. The bandgap of the oriented ZnO film was found to decrease with rise in temperature. The work indicates a promising application of the system as a temperature sensor and highlights an efficient scientific tool to study optical properties of thin film under varying ambient conditions.
Disk Accretion and the Stellar Birthline

We present a simplified analysis of some effects of disk accretion on the early evolution of fully convective, low-mass pre-main-sequence stars. Our analysis builds on the previous seminal work of Stahler, but it differs in that the accretion of material occurs over a small area of the stellar surface, such as through a disk or magnetospheric accretion column, so that most of the stellar photosphere is free to radiate to space. This boundary condition is similar to the limiting case considered by Palla & Stahler for intermediate-mass stars. We argue that for a wide variety of disk mass accretion rates, material will be added to the star with relatively small amounts of thermal energy. Protostellar evolution calculated assuming this “low-temperature” limit of accretion generally follows the results of Stahler because of the thermostatic nature of deuterium fusion, which prevents protostars from contracting below a “birthline” in the H-R diagram. Our calculated protostellar radii tend to fall below Stahler's at higher masses; the additional energy loss from the stellar photosphere in the case of disk accretion tends to make the protostar contract. The low-temperature disk accretion evolutionary tracks never fall below the deuterium-fusion birthline until the internal deuterium is depleted, but protostellar tracks can lie above the birthline in the H-R diagram if the initial radius of the protostellar core is large enough or if rapid disk accretion (such as might occur during FU Ori outbursts) adds significant amounts of thermal energy to the star. These possibilities cannot be ruled out by either theoretical arguments or observational constraints at present, so that individual protostars might evolve along a multiplicity of birthlines with a modest range of luminosity at a given mass. Our results indicate that there are large uncertainties in assigning ages for the youngest stars from H-R diagram positions, given the uncertainty in birthline positions. Our calculations also suggest that the relatively low disk accretion rates characteristic of T Tauri stars below the birthline cause low-mass stars to contract only slightly faster than normal Hayashi track evolution, so that ages for older pre-main-sequence stars estimated from H-R diagram positions are relatively secure.
Coding of Musical Structure and the Trion Model of Cortex

Guided by the Mountcastle organizational principle for the column as the basic neuronal network in the cortex, we developed the trion model. An essential feature of the model is that it is highly structured in time and in spatial connections. Simulations of a network of trions have shown that large numbers of quasi-stable, periodic spatial-temporal firing patterns can be excited. These patterns can be readily enhanced by only a small change in connection strengths, and the patterns evolve in certain natural sequences from one to another. With only somewhat different parameters than those used for studying memory and pattern recognition, much more flowing and intriguing patterns emerged from the simulations. The results were striking when these probabilistic evolutions were mapped onto pitches and instrument timbres to produce music: For example, different simple mappings of the same evolution give music having the "flavor" of a minuet, a waltz, certain folk music, or styles of specific periods of Western art music. A theme can be learned so that evolutions have this theme and its variations recur. We suggest that we have found a viable cortical model for the coding of certain aspects of musical structure in human composition and perception. Further, we propose that the trion model is relevant for examining creativity in those higher cognitive functions of mathematics and chess that are similar to music.
Investigation of the effects of temporal thermal gradients in fiber optic gyroscope sensing coils, part 2

We investigate the effects of the nonreciprocity caused by time-varying, radial thermal gradients in interferometric fiber gyroscope sensing coils. Four identical sensing coils have been wound with elliptical core and Panda polarization-maintaining fibers in straight and quadrupolar wind configurations. The induced gyro bias drift, measured as a function of the elevated temperature and time, is presented and compared with a simple heat-conduction model. Qualitative agreement is reached with suitable choices of material parameters.
Polynomial approximations to finitely oscillating functions

The main result of this paper is an algorithm for the calculation of this polynlomial, which is first motivated by an indepenidenit proof for the existence of P. A funietion f is said to be finitely oscillating if it has at most a finite niumher of relative extrema. The following mode of approximating a continuous finiitely oscillating function f in the uniform norm so that the oscillations are preserved, is discussed: first obtain a polynomial P of minimal degree which has the same variation as f and then obtain an increasinig polynom-ial Q such that P(Q) agrees with f at all its relative extrema. Two theorems are given in the last sectioIn, to show that this method of approximation is always possible.
Fast-wave heating of a two-component plasma

The use of the compressional hydromagnetic mode (also called the magnetosonic or, simply, the fast wave) is examined in some detail with respect to the heating of a tritium plasma containing a few percent deuterium. Efficient absorption of wave energy by the deuteron component is found when ω = ωC (deuterons), with Qwave ⪆ 100. Reasonable efficiencies are found also for electron heating, but coherence effects between transit-time and Landau damping for electrons reduce the total absorption for both processes to one-half of the transit-time power, calculated separately. The fusion output of a two-component neutral-injected plasma can be enhanced by selective heating of the injected deuterons. Also, selective deuteron absorption may be used for ion-tail creation by radiofrequency excitation alone, as an alternative to neutral injection. The dominant behaviour of the high-energy deuteron distribution function is found to be f(v) ∼ exp[(3/2)∫vdv/<(Δv⊥)2>], where is the Chandrasekhar-Spitzer drag coefficient, and <(Δv⊥)2> is the Kennel-Engelmann quasi-linear diffusion coefficient for wave-particle interaction at the deuteron cyclotron frequency. An analytic solution to the one-dimensional Fokker-Planck equation, with r.f. -induced diffusion, is developed, and using this solution together with Duane's fit to the D-T fusion cross-section, it is found that the nuclear-fusion power output from an r.f. -produced two-component plasma can significantly exceed the incremental (radiofrequency) power input.