Spectra generated by a confined softcore Coulomb potential

Analytic and approximate solutions for the energy eigenvalues generated by a confined softcore Coulomb potentials of the form a/(r+\beta) in d>1 dimensions are constructed. The confinement is effected by linear and harmonic-oscillator potential terms, and also through `hard confinement' by means of an impenetrable spherical box. A byproduct of this work is the construction of polynomial solutions for a number of linear differential equations with polynomial coefficients, along with the necessary and sufficient conditions for the existence of such solutions. Very accurate approximate solutions for the general problem with arbitrary potential parameters are found by use of the asymptotic iteration method.Comment: 17 pages, 2 figure

Memory of the Unjamming Transition during Cyclic Tiltings of a Granular Pile

Discrete numerical simulations are performed to study the evolution of the micro-structure and the response of a granular packing during successive loading-unloading cycles, consisting of quasi-static rotations in the gravity field between opposite inclination angles. We show that internal variables, e.g., stress and fabric of the pile, exhibit hysteresis during these cycles due to the exploration of different metastable configurations. Interestingly, the hysteretic behaviour of the pile strongly depends on the maximal inclination of the cycles, giving evidence of the irreversible modifications of the pile state occurring close to the unjamming transition. More specifically, we show that for cycles with maximal inclination larger than the repose angle, the weak contact network carries the memory of the unjamming transition. These results demonstrate the relevance of a two-phases description -strong and weak contact networks- for a granular system, as soon as it has approached the unjamming transition.Comment: 13 pages, 15 figures, soumis \`{a} Phys. Rev.

Evaluation of the Performance of Waterproof Perimeter Barriers : Numerical and Physical Models

Fil: Capdevila, Julio A. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; Argentina.Fil: Zanni, Enrique. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; Argentina.Fil: Nasser, José J. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; Argentina.Collapsible soils cover a great part of Córdoba city in Argentina. Loessian soil is formed by silt and sand particles with clay bridges, generating macropores susceptible to collapse upon wetting under load. Those structures that are superficially supported on this type of soils are susceptible of suffering damage because of soil wetting. Some actions can be taken to prevent the effect of this phenomenon, such as trays for pipes, storm drains, deeper foundations and perimetral sidewalks. At present, there is no literature about the design or hydraulic behavior of perimetral sidewalks. In this paper different types of barriers are going to be implemented in numerical and physical models. The purpose is to analyze and evaluate the barriers performance to avoid supporting soil wetting and settlement of foundations due to soil collapse. In this sense, a shallow foundation prototype was constructed and different perimetral barriers were materialized. A design rainfall was applied over the model. Simultaneously, this prototype was implemented in a finite element software to validate numerical results with physical ones. The characterization of the materials that constitute the proposed barriers and foundation soil are carried out to the numerical models. Obtained results allow making the evaluation of performance of the different implemented barriers validating the numerical model results and making some recommendations for the proper design of waterproof perimeter barriers.http://www.seipub.org/scea/PaperInfo.aspx?ID=18325info:eu-repo/semantics/publishedVersionFil: Capdevila, Julio A. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; Argentina.Fil: Zanni, Enrique. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; Argentina.Fil: Nasser, José J. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; Argentina.Diseño Arquitectónic

Taming the Yukawa potential singularity: improved evaluation of bound states and resonance energies

Using the tools of the J-matrix method, we absorb the 1/r singularity of the Yukawa potential in the reference Hamiltonian, which is handled analytically. The remaining part, which is bound and regular everywhere, is treated by an efficient numerical scheme in a suitable basis using Gauss quadrature approximation. Analysis of resonance energies and bound states spectrum is performed using the complex scaling method, where we show their trajectories in the complex energy plane and demonstrate the remarkable fact that bound states cross over into resonance states by varying the potential parameters.Comment: 8 pages, 2 tables, 1 figure. 2 mpg videos and 1 pdf table file are available upon request from the corresponding Autho

Development of aquatic skills in a child with visual and intellectual disability

El objetivo de este estudio de caso fue analizar el desarrollo de las habilidades acuáticas de un niño con deficiencia visual total e intelectual severa. Para esto, este niño, de siete años de edad, participó en un programa de actividades acuáticas, con atención individualizado, durante 12 sesiones. La matriz de evaluación de las habilidades acuáticas de Winnick (2010) fue utilizada como instrumento para recolectar datos. El análisis de los datos sucedió de forma descriptiva. El alumno presentó desempeño positivo en tres categorías: Entradas, salidas y orientación en el agua. Se destaca la comprensión de la entrada y de la salida por la rampa adaptada; el dominio en la realización del giro lateral y del zambullida frontal; y, la mejoría en las 14 habilidades de la categoría orientación en el agua. Las actividades acuáticas le permitieron al alumno superar sus dificultades dando un salto cualitativo en la ejecución de determinadas habilidadesThe purpose of this descriptive case study was to analyze the development of aquatic skills of a child with total visual and severe intellectual disability. Therefore, this child, seven years old, participates in a program of water activities, with individualized service for 12 sessions. The assessment matrix of aquatic skills, Winnick (2010), was used as a tool for data collection. The student showed positive performances in three categories: entering and coming out of the water and in the water orientation. The understanding of the entry is emphasized and exit through the adapted ramp; controlling the performance of lateral bearing and frontal diving; and, improvement on the 14 skills in the category of water orientation. The water activities allowed the student to overcome difficulties by making a qualitative improvement in the performance of certain skill

Spectral characteristics for a spherically confined -1/r + br^2 potential

We consider the analytical properties of the eigenspectrum generated by a class of central potentials given by V(r) = -a/r + br^2, b>0. In particular, scaling, monotonicity, and energy bounds are discussed. The potential $V(r)$ is considered both in all space, and under the condition of spherical confinement inside an impenetrable spherical boundary of radius R. With the aid of the asymptotic iteration method, several exact analytic results are obtained which exhibit the parametric dependence of energy on a, b, and R, under certain constraints. More general spectral characteristics are identified by use of a combination of analytical properties and accurate numerical calculations of the energies, obtained by both the generalized pseudo-spectral method, and the asymptotic iteration method. The experimental significance of the results for both the free and confined potential V(r) cases are discussed.Comment: 16 pages, 4 figure

Shear Viscosity in a Perturbative Quark-Gluon-Plasma

Among the key features of hot and dense QCD matter produced in ultra-relativistic heavy-ion collisions at RHIC is its very low shear viscosity, indicative of the properties of a near-ideal fluid, and a large opacity demonstrated by jet energy loss measurements. In this work, we utilize a microscopic transport model based on the Boltzmann equation with quark and gluon degrees of freedom and cross sections calculated from perturbative Quantum Chromodynamics to simulate an ideal Quark-Gluon-Plasma in full thermal and chemical equilibrium. We then use the Kubo formalism to calculate the shear viscosity to entropy density ratio of the medium as a function of temperature and system composition. One of our key results is that the shear viscosity over entropy-density ratio $\eta/s$ becomes invariant to the chemical composition of the system when plotted as a function of energy-density instead of temperature.Comment: 11 pages, 8 figures: version #2 contains some revisions and added references to clarify relationship to previously published wor

Handwritten Signature Verification using Deep Learning

Every person has his/her own unique signature that is used mainly for the purposes of personal identification and verification of important documents or legal transactions. There are two kinds of signature verification: static and dynamic. Static(off-line) verification is the process of verifying an electronic or document signature after it has been made, while dynamic(on-line) verification takes place as a person creates his/her signature on a digital tablet or a similar device. Offline signature verification is not efficient and slow for a large number of documents. To overcome the drawbacks of offline signature verification, we have seen a growth in online biometric personal verification such as fingerprints, eye scan etc. In this paper we created CNN model using python for offline signature and after training and validating, the accuracy of testing was 99.70%

Realization of the mean-field universality class in spin-crossover materials

In spin-crossover materials, the volume of a molecule changes depending on whether it is in the high-spin (HS) or low-spin (LS) state. This change causes distortion of the lattice. Elastic interactions among these distortions play an important role for the cooperative properties of spin-transition phenomena. We find that the critical behavior caused by this elastic interaction belongs to the mean-field universality class, in which the critical exponents for the spontaneous magnetization and the susceptibility are $\beta = 1/2$ and $\gamma = 1$, respectively. Furthermore, the spin-spin correlation function is a constant at long distances, and it does not show an exponential decay in contrast to short-range models. The value of the correlation function at long distances shows different size-dependences: $O(1/N)$, $O(1/\sqrt{N})$, and constant for temperatures above, at, and below the critical temperature, respectively. The model does not exhibit clusters, even near the critical point. We also found that cluster growth is suppressed in the present model and that there is no critical opalescence in the coexistence region. During the relaxation process from a metastable state at the end of a hysteresis loop, nucleation phenomena are not observed, and spatially uniform configurations are maintained during the change of the fraction of HS and LS. These characteristics of the mean-field model are expected to be found not only in spin-crossover materials, but also generally in systems where elastic distortion mediates the interaction among local states.Comment: 13 pages, 16 figure

Nonequilibrium Thermodynamics of Amorphous Materials I: Internal Degrees of Freedom and Volume Deformation

This is the first of three papers devoted to the nonequilibrium thermodynamics of amorphous materials. Our focus here is on the role of internal degrees of freedom in determining the dynamics of such systems. For illustrative purposes, we study a solid whose internal degrees of freedom are vacancies that govern irreversible volume changes. Using this model, we compare a thermodynamic theory based on the Clausius-Duhem inequality to a statistical analysis based directly on the law of increase of entropy. The statistical theory is used first to derive the the Clausius-Duhem inequality. We then use the theory to go beyond those results and obtain detailed equations of motion, including a rate factor that is enhanced by deformation-induced noisy fluctuations. The statistical analysis points to the need for understanding how both energy and entropy are shared by the vacancies and their environments.Comment: 7 pages. First of a three-part serie