Miracle-dz/UniFAR-FTUs huggingface dataset:
Three‐dimensional stochastic analysis of macrodispersion in aquifers

The dispersive mixing resulting from complex flow in three-dimensionally heterogeneous porous media is analyzed using stochastic continuum theory. Stochastic solutions of the perturbed steady flow and solute transport equations are used to construct the macroscopic dispersive flux and evaluate the resulting macrodispersivity tensor in terms of a three-dimensional, statistically anisotropic input covariance describing the hydraulic conductivity. With a statistically isotropic input covariance, the longitudinal macrodispersivity is convectively controlled, but the transverse macrodispersivity is proportional to the local dispersivity and is several orders of magnitude smaller than the longitudinal term. With an arbitrarily oriented anisotropic conductivity covariance, all components of the macrodispersivity tensor are convectively controlled, and the ratio of transverse to longitudinal dispersivity is of the order of 10−1. In this case the off-diagonal components of the dispersivity tensor are significant, being numerically larger than the diagonal transverse terms, and the transverse dispersion process can be highly anisotropic. Dispersivities predicted by the stochastic theory are shown to be consistent with controlled field experiments and Monte Carlo simulations. The theory, which treats the asymptotic condition of large displacement, indicates that a classical gradient transport (Fickian) relationship is valid for large-scale displacements.
Controllability and observability of linear retarded systems in Banach spaces

Abstract Controllability and observability are studied for linear retarded systems in a Banach space X. Both the X-exact and the X-approximate controllability are considered and a number of necessary and sufficient conditions in terms of the coefficient operators and/or the fundamental solution are presented. Various corresponding concepts for observability are introduced and the duality between controllability and observability is clarified. An applicable condition for the X-approximate controllability and the X*-observability is established under the assumptions that the control is a finite dimensional one and the system of generalized eigenspaces is projectively complete. The condition is stated in terms of eigenvectors and controllers.
ON THE MAXIMUM INTENSITY OF HURRICANES

Abstract The minimum pressure that can occur within a hurricane is related to the temperature of the sea surface over which it moves. This is done by making certain assumptions and synthesizing an eye sounding, which is used to compute the lowest pressure of the storm. The validity of the computed sounding is tested on eight hurricanes. A series of composite 200-mb charts is constructed from five of the eight hurricanes which reached great intensity to show one synoptic situation which results in maximum deepening. These are contrasted to a similar series of composite charts prepared for storms which reached only minor intensity.
Optimal Political Districting by Implicit Enumeration Techniques

An algorithm is given which finds all optimal solutions, for a given set of criteria, to political redistricting problems. Using “population units” as indivisible elements, the first phase generates all feasible districts, where feasibility indicates contiguity, compactness and limited population deviation. The second phase finds that set of M feasible districts which “covers” each population unit exactly once, and minimizes the maximum deviation of any district population from the mean district population. Computational results indicate that states with 40 counties or fewer can be solved in less than 10 minutes on an IBM 7094. However, our attempt to solve a 55 county state was unsuccessful.
Cathodoluminescence study on dislocations in silicon

A study was made on the characteristics of cathodoluminescence (CL) from Si crystals with various configurations of dislocations. D3 and D4 were observed along slip lines, while D1 and D2 were found to be strong in the region where plural slip lines intersect each other. It was shown that not only Lomer–Cottrell dislocations but also jogs act as recombination centers for D1 and D2 luminescence. The spatial distributions of D1 and D2 luminescence were observed to be similar to each other, this was also true of D3 and D4. The effect of hydrogenation on CL distribution was also investigated. Contrary to the reports of other groups, no evidence was obtained on the enhancement of D line luminescence due to metal contamination.
The forward scattering of resonance radiation, with special reference to double resonance and level-crossing experiments

A theoretical and experimental study has been made of the intensity of forward scattered light in conditions of radio-frequency double resonance and level-crossing. The main conclusions are (i) that the magnetic resonance and level-crossing effects which are familiar in the laterally scattered light are to be found also in the forward scattered light, but (ii) that the resonance curves are Doppler-broadened, and the strength of the oscillatory field necessary to generate them is correspondingly increased, and (iii) that coherence narrowing is much more pronounced in forward than in lateral scattering. The differences derive from the coherence between the radiation from different atoms which is present in forward, but not in lateral scattering, and which is implicitly recognized in the classical theory of the propagation of light in polarizable media. The equations of electromagnetism form the basis of the present analysis. In the presence of the oscillatory magnetic field the polarization tensor is complex and time-dependent. The time dependence leads to the result that the number of eigenwaves necessary to describe propagated waves in the medium is four, as against the usual two. An arbitrary wave is resolved into a superposition of the four eigenwaves, all of which have different propagation constants. The analysis is very general, and is applicable to experiments with lasers. The components of the polarization tensor are derived by finding first the polarizability of individual atoms from a semi-classical theory of their interaction with light and magnetic fields. The macroscopic polarization, obtained by summing over individual atoms, is then given by folding the individual polarizabilities with the Doppler distribution of resonance frequencies. In the particular case studied in detail (the inter-combination resonance line, 2537 A, in mercury), the Doppler width is much greater than the radiation width, and the imaginary (absorptive) part of the polarizability is Gaussian. Expressions are derived in a ‘weak scattering’ approximation for the intensity of the forward scattered light. They are magnetic resonance functions which are found to be the Doppler-broadened equivalents of the familiar functions, based on Lorentzians, characteristic of scattering by a single atom. In the case of double resonance the forward scattered light is strongly modulated, as is the laterally scattered light. To investigate coherence narrowing, the zero-field level-crossing has been studied with the restriction of ‘weak scattering’ removed. The result is obtained that the width of levelcrossing curves is inversely proportional to the vapour density for magnetic fields such that the Zeeman splitting is small in relation to the Doppler width. This analytical result has been verified experimentally.
Photoluminescence study of ZnCdO alloy

The photoluminescence (PL) properties of ZnCdO alloy are investigated at various temperatures. Each PL profile contains four distinct peaks: P1, P2, P3, and P4. Peak P4 is due to free-excitonic recombination. The temperature mapping of the P3 peak position shows an S-shaped shift similar to the InGaN system due to the inhomogeneous distribution of Cd in ZnCdO alloy. The peak P2 is attributed to the phonon replica of the localized excitonic emission (P3). The linewidth of the photoluminescence profiles of the ZnCdO alloy is shown to depend on the concentration of Cd.
The design of TSK‐type fuzzy controllers using a new hybrid learning approach

In this paper, the TSK‐type fuzzy controllers with a novel hybrid learning approach (TFC‐HLA) are proposed. The proposed hybrid learning approach consists of the self‐clustering algorithm (SCA) and the dynamic‐form symbiotic evolution (DSE). First, the proposed SCA is used to identify a parsimonious internal structure. Secondly, the proposed DSE uses the sequential‐search‐based dynamic evolution method. Better combinations of the chromosomes will be initially generated while better mutation points will be determined to perform dynamic mutation. The advantages of the proposed learning algorithm are that, first, it converges quickly and the obtained fuzzy rules are more precise. Second, the proposed TFC‐HLA controller only requires a few population sizes. Third, the DSE constructs only four fuzzy controllers every generation. The performance of the TFC‐HLA controller compares excellently with other existing models in our control simulations. Copyright © 2005 John Wiley & Sons, Ltd.
Visible resonant modes in GaN-based photonic crystal membrane cavities

Photonic crystal membrane cavities play a key role as building blocks in the realization of several applications, including quantum information and photonic circuits. Thus far, there has been no work on defect cavities with active layers emitting in the UV to green range of the spectrum based on the (Al,In,Ga)N material system. While this material system has great potential for a new generation of optoelectronic devices, there are several obstacles for the fabrication of GaN-based membrane cavities, including the absence of a conventional selective chemical wet etch. Here, we demonstrate the first fabrication of fully undercut GaN photonic crystal membranes containing an InGaN multiquantum well layer, fabricated using band-gap-selective photoelectrochemical etching. A postfabrication coating of Ta2O5 is used to tune the cavity modes into resonance with the quantum well emission, and the fabricated membranes exhibit resonant modes with Q=300.
Equivalence between macroscopic quantum superpositions and maximally entangled states: Application to phase-shift detection

Maybe the most attractive and puzzling subjects of the quantum theory can be encountered within the fuzzy boundary between the quantum and classical realms. Among the paradigms of quantum behavior revealed by the lack of classical counterpart, we may mention the quantum limits to precision measurements, coherent superpositions of macroscopically distinct states, entanglement, and extreme quantum correlations. Since these are examples of purely quantum features, it may be expected that they are tightly connected at a very fundamental level. In this paper, we show that the quantum superposition of two macroscopically distinct coherent states is a maximally entangled state. Among other consequences, this implies that maximally entangled states may be easily produced using the same schemes devised to generate quantum superpositions of macroscopically distinct states. This is interesting since these quantum superpositions have been widely studied and have been already generated experimentally @1‐5#. Other proposals to generate maximally entangled states in diverse contexts may be found in Refs. @6,7#. Furthermore, this equivalence implies that macroscopic ~or mesoscopic! quantum superpositions may find applications in areas where quantum correlations are relevant such as the demonstration of quantum nonlocality, cryptography, quantum communication, and quantum computation. In particular, it is known that maximally entangled states may be applied to perform high-precision measurements @6,8# . I n this paper, we will show that the superposition of macroscopically distinct coherent states allows us to perform phase-shift measurements reaching the maximum sensitivity allowed by quantum physics ~i.e., the Heisenberg limit @8,9#! This is interesting because it implies that the problem of precision phase measurements can benefit from the advances achieved in the area of macroscopic quantum superpositions. In Sec. II, we demonstrate the equivalence between maximally entangled states and the superposition of macroscopically distinct coherent states. In Sec. III, we show how these states may be used to reach the Heisenberg limit in precision phase measurements. We propose a practical scheme based on currently available experimental arrangements already used to generate these states in the field of quantum optics @2,3#.
Recursions and fast Fourier transforms for a new bivariate aggregate claims model

Insurance companies typically face multiple sources (types) of claims. Therefore, modelling dependencies among different types of risks is extremely important for evaluating the aggregate claims of an insurer. In this paper, we first introduce a multivariate aggregate claims model, which allows dependencies among claim numbers as well as dependencies among claim sizes. For this proposed model, we derive recursive formulas for the joint probability functions of different types of claims. In addition, we extend the concept of exponential tilting to the multivariate fast Fourier transform and use it to compute the joint probability functions of the various types of claims. We provide numerical examples to compare the accuracy and efficiency of the two computation methods.
Realistic absorption coefficient of each individual film in a multilayer architecture

A spectrophotometric strategy, termed multilayer-method (ML-method), is presented and discussed to realistically calculate the absorption coefficient of each individual layer embedded in multilayer architectures without reverse engineering, numerical refinements and assumptions about the layer homogeneity and thickness. The strategy extends in a non-straightforward way a consolidated route, already published by the authors and here termed basic-method, able to accurately characterize an absorbing film covering transparent substrates. The ML-method inherently accounts for non-measurable contribution of the interfaces (including multiple reflections), describes the specific film structure as determined by the multilayer architecture and used deposition approach and parameters, exploits simple mathematics, and has wide range of applicability (high-to-weak absorption regions, thick-to-ultrathin films). Reliability tests are performed on films and multilayers based on a well-known material (indium tin oxide) by deliberately changing the film structural quality through doping, thickness-tuning and underlying supporting-film. Results are found consistent with information obtained by standard (optical and structural) analysis, the basic-method and band gap values reported in the literature. The discussed example-applications demonstrate the ability of the ML-method to overcome the drawbacks commonly limiting an accurate description of multilayer architectures.
An Impact Dynamics Modeling Method with Tangential Impulse in Three-Dimensional Space

This paper studies the impact of two rigid bodies considering tangential friction in three dimensional space. It extends Stronge’s spring-based planar contact structure to three dimensions by introducing three orthogonal virtual springs. Impact analysis is carried out using normal impulse rather than time as the only independent variable, unlike previous work on tangential impulse. This makes the algorithm more compact. At last, collision is governed by a system of differential equations. Modularity of the impact model makes it easy to be integrated into a multi-body system.
INTERBAND ELECTRON-ELECTRON SCATTERING AND TRANSPORT PHENOMENA IN SEMICONDUCTORS

The effect of interband electron-electron scattering (electron-hole scattering, light hole-heawy hole scattering, etc,) on the electrical transport phenomena is studied using a variational method obtained by a generalization of Kohler's variation principle to a multiband conductor. It is assumed that the electronic structure is given by parabolic conduction and valence bands, separated from each other by DELTA E >> k/sub B/T; the valence band may be twofold degenerate; the average occupation numbers of electronic eigenstates are given by Permi-Dirac statistics; the dynamical interaction between charge carriers is described by a shielded Coulomb potential. Assuming nondegenerate semiconductors, acoustical and optical phonon scattering and ion scattering are considered, besides electronelectron scattering. Quantitative results are obtained for the electrical conductivity, the heat conductivity, and the Seebeck coefficient, including the ambipolar effect. The results can easily be applied to cases of physical interest; hole-hole scattering and mobility of p germanium, intercarrier scattering and mobility of intrinsic germanium, transient conductivity of charge carriers in germanium produced by short pulses of high- energy electrons, intercarrier scaitering and its influence on the heat conductivity, and the Wiedemann-Franz ratio of intrinsic semiconductors are considered. (auth)
ANALYSIS OF A MATHEMATICAL MODEL OF TUMOR LYMPHANGIOGENESIS

Tumor survival, growth and dissemination are associated with the formation of both new blood vessels (angiogenesis) and new lymph vessels (lymphangiogenesis). A mathematical model of tumor lymphangiogenesis was recently developed by the authors, based on experimental results established in the last five years. The model consists of a coupled system of eight parabolic equations. In this paper we prove existence and uniqueness of a solution for this system, for all t>0.
Large Eddy simulation of high-Reynolds-number free and wall-bounded flows

The ability to simulate complex unsteady flows is limited by the current state of the art of subgrid-scale (SGS) modeling, which invariably relies on the use of Smagorinsky-type isotropic eddy-viscosity models. Turbulent flows of practical importance involve inherently three-dimensional unsteady features, often subjected to strong inhomogeneous effects and rapid deformation, which cannot be captured by isotropic models, Although some available improved SGS models can outperform the isotropic eddy-viscosity models, their practical use is typically limited because of their complexity, Development of more-sophisticated SGS models is actively pursued, and it is desirable to also investigate alternative nonconventional approaches. In ordinary large eddy simulation (LES) approaches models are introduced for closure of the low-pass filtered Navier-Strokes equations (NSE). A promising LES approach is the monotonically integrated LES(MILES), which involves solving the unfiltered NSE using high-resolution monotone algorithms; in this approach, implicit SGS models. provided by intrinsic nonlinear high-frequeacy filters built into the convection discretization, are coupled naturally to the resolvable scales of the flow. Formal properties of the effective SGS modeling using MILES are documented using databases of simulated free and wall-bounded inhomogeneous flows, including isotropic decaying turbulence, transitional jets, and channel flows. Mathematical and physical aspects of (implicit) SGS modeling through the use of nonlinear flux limiters are addressed using a formalism based on the modified LES equations.
Monotonicity of the Number of Passages in Linear Chains and of the Basic Reproduction Number in Epidemic Models

In models for infectious diseases, the basic reproduction number is the crucial parameter which determines the possibility of an outbreak. In simple situations it depends in a monotone way on the infectivity. Non-monotone behavior may occur in diseases where infectivity depends on time since infection and where transmission depends on social structure, as is shown by an example. A typical application is the HIV infection where transmission rates depend on existing pair bonds and infectivity changes drastically over time. For a class of epidemic models with pair formation models and infectivity depending on time since infection it is shown that the basic reproduction number is a monotone function of infectivity. This observation is a consequence of a general result on a class of cyclic linear reaction chains with tridiagonal structure for which it is shown that the number of passages depends in a monotone way on the rates.
Granular Drag and the Kinetics of Jamming

GRANULAR DRAG AND THE KINETICS OF JAMMING Theodore A. Brzinski III Douglas J. Durian The first part of this thesis focuses on the study of the force exerted by a granular packing on an intruder. During impact, this force can be described by the linear combination of an inertial drag and a rate-independent frictional force that is proportional to depth [31, 64]. We measure the torque acting on a rod rotated perpendicular to its axis in a granular bed at steady state, and demonstrate that the resisting force is of the same form, though smaller. We then alter the hydrostatic loading on the bed by generating a homogenized airflow through the bed, and show that for horizontal motion the frictional force is due to friction acting at gravity-loaded contacts. Next we directly measure the force acting on quasistatically, vertically lowered intruders under two sets of varied conditions. First we vary the shape of the projectile in order to alter the fraction of the projectile surface that moves parallel vs perpendicular to the medium, and find that the frictional force acts primarily normal to the intruder surface. Second, we alter the hydrostatic loading as above, and confirm that gravity-loading of the grains sets the magnitude of the resisting force for quasi-static vertical motion as well. Finally, we consider the case of impact onto wet grains. We conduct conventional impact experiments wherein a spherical projectile impacts onto a granular packing with a known impact speed. We vary the liquid, impact speed, and degree of saturation, and find that the penetration depth is decreased for all wetting fractions, and that the penetration depth has a non-monotonic dependence on liquid saturation. In the fully saturated case, we recover the same scaling of penetration depth with geometry, impact speed and packing density as in the dry case, though the penetrations are shallower, suggesting a hydrodynamic contribution to the net stopping force.
Divergence empirique et vraisemblance empirique généralisée

In this paper, we generalize the results obtained with the Kullback distance (corresponding to empirical likelihood) and Cressie-Read metrics (generalized empirical likelihood) to general Phi*-discrepancies, for some convex functions Phi satisfying a few regularity properties. In particular, we introduce a new Bartlett correctable family of empirical discrepancies, the Quasi-Kullback, out of Cressie-Read family, which possess interesting finite sample properties. We conclude this work with some simulations in the multidimensional case for different discrepancies.
Leakage current in InGaAsP avalanche photodiodes

The increased leakage current in InGaAsP APD’s near breakdown is found to be a rather uniform bulk property, not associated with conventional microplasmas, dislocations, or surface effects. Surface effects were eliminated by the fabrication of guard ring APD’s, but the increased leakage current persisted. Surface effects were further ruled out by a statistical study of the leakage current in a large sample of APD’s. The study shows conclusively that the leakage current is proportional to diode area, not perimeter.