Correlation of transport and magnetic critical currents in melt-processed YBa2Cu3O7-δ thick films

Transport critical current measurements have been carried out on melt-processed thick films of YBa2Cu3O7-δ on yttria-stabilized zirconia in fields of up to 8 T both within grains and across grain boundaries. These measurements yield Jc values of ∼3000 A cm-2 at 4.2 K and zero magnetic field and 400 A cm -2 at 77 K and zero magnetic field, taking the entire sample width as the definitive dimension. Optical and scanning electron microscopy reveals that the thick-film grains consist typically of a central "hub" region ∼50 μm in diameter, which is well connected to radial subgrains or "spokes" which extend ∼1 mm to define the complete grain structure. Attempts have been made to correlate the transport measurements of inter- and intra-hub-and-spoke (H-S) critical current with values of this parameter derived previously from magnetization measurements. Analysis of the transport measurements indicates that current flow through H-S grains is constrained to paths along the spokes via the grain hub. Taking the size of the hub as the definitive dimension yields an intra-H-S grain Jc of ∼60 000 A cm-2 at 4.2 K and 0 T, which is in reasonable agreement with the magnetization data. Experiments in which the hub is removed from individual grains confirm that this feature determines critically the J c of the film.

Estrategias discursivas y proverbios en la poesía del Marqués de Santillana recopilada en el Cancionero General de 1511

Integran este número de la revista ponencias presentadas en Studia Hispanica Medievalia VIII : Actas de las X Jornadas Internacionales de Literatura Española Medieval, 2011, y de Homenaje al Quinto Centenario del Cancionero General de Hernando del Castillo.

Sapientia (Índice general)

Contenido: Índice general de autores y materias. Año I, 1946 - Año X, 1955

A general design method for electric machines using magnetic circuit model considering the flux saturation problem

This paper proposes an analytical approach that is generalized for the design of various types of electric machines based on a physical magnetic circuit model. Conventional approaches have been used to predict the behavior of electric machines but have limitations in accurate flux saturation analysis and hence machine dimensioning at the initial design stage. In particular, magnetic saturation is generally ignored or compensated by correction factors in simplified models since it is difficult to determine the flux in each stator tooth for machines with any slot-pole combinations. In this paper, the flux produced by stator winding currents can be calculated accurately and rapidly for each stator tooth using the developed model, taking saturation into account. This aids machine dimensioning without the need for a computationally expensive finite element analysis (FEA). A 48-slot machine operated in induction and doubly-fed modes is used to demonstrate the proposed model. FEA is employed for verification.

El Cancioneiro Geral portugués y algunas distinciones de su congénere, El Cancionero General

Integran este número de la revista ponencias presentadas en Studia Hispanica Medievalia VIII : Actas de las X Jornadas Internacionales de Literatura Española Medieval, 2011, y de Homenaje al Quinto Centenario del Cancionero General de Hernando del Castillo.

Un impreso poético en el cancionero manuscrito EM6 : el pliego suelto 99*RN y el Cancionero General

Integran este número de la revista ponencias presentadas en Studia Hispanica Medievalia VIII : Actas de las X Jornadas Internacionales de Literatura Española Medieval, 2011, y de Homenaje al Quinto Centenario del Cancionero General de Hernando del Castillo.

Una teoría general para la enseñanza del derecho civil : una propuesta para el Bicentenario

Resumen: El presente trabajo propone elementos para una reformulación de la enseñanza del Derecho Civil en la Argentina del Bicentenario. Parte del análisis del estado actual de la enseñanza en esta rama jurídica, con especial referencia a sus etapas históricas. Considera luego lo que se denomina “el modelo del cententario”, con particular atención a la influencia de la modernidad ilustrada y la cultura del Código. Evalúa luego la cuestión a partir de la tensión entre modernidad ilustrada y posmodernidad, proponiendo una alternativa al modelo de enseñanza surgido de la posmodernidad. Como hipótesis de trabajo propone una lectura de la denominada cultura jurídica desde los principios del derecho, y aportar así una alternativa desde la perspectiva del realismo jurídico clásico.

Sapientia, 1972, Vol. XXVII, nº 104 (Índice general)

Contenido: Índice general de autores y materias. Año I, 1946 – Año XXV, 1970

Sequential decision making in general state space models

Many problems in control and signal processing can be formulated as sequential decision problems for general state space models. However, except for some simple models one cannot obtain analytical solutions and has to resort to approximation. In this thesis, we have investigated problems where Sequential Monte Carlo (SMC) methods can be combined with a gradient based search to provide solutions to online optimisation problems. We summarise the main contributions of the thesis as follows. Chapter 4 focuses on solving the sensor scheduling problem when cast as a controlled Hidden Markov Model. We consider the case in which the state, observation and action spaces are continuous. This general case is important as it is the natural framework for many applications. In sensor scheduling, our aim is to minimise the variance of the estimation error of the hidden state with respect to the action sequence. We present a novel SMC method that uses a stochastic gradient algorithm to find optimal actions. This is in contrast to existing works in the literature that only solve approximations to the original problem. In Chapter 5 we presented how an SMC can be used to solve a risk sensitive control problem. We adopt the use of the Feynman-Kac representation of a controlled Markov chain flow and exploit the properties of the logarithmic Lyapunov exponent, which lead to a policy gradient solution for the parameterised problem. The resulting SMC algorithm follows a similar structure with the Recursive Maximum Likelihood(RML) algorithm for online parameter estimation. In Chapters 6, 7 and 8, dynamic Graphical models were combined with with state space models for the purpose of online decentralised inference. We have concentrated more on the distributed parameter estimation problem using two Maximum Likelihood techniques, namely Recursive Maximum Likelihood (RML) and Expectation Maximization (EM). The resulting algorithms can be interpreted as an extension of the Belief Propagation (BP) algorithm to compute likelihood gradients. In order to design an SMC algorithm, in Chapter 8 uses a nonparametric approximations for Belief Propagation. The algorithms were successfully applied to solve the sensor localisation problem for sensor networks of small and medium size.

Zoología general

Es una asignatura básica en la formación del ingeniero en Recursos Naturales Renovables y tiene como precedencia los conocimientos de las asignaturas de Biología; Introducción a los Recursos Naturales; Botánica Básica y Ecología. Además sirve de base a diferentes asignaturas tanto básicas como específicas, ya que en ella se imparten conocimientos técnicos al estudiante con el fin de que pueda desarrollarse de manera satisfactoria en otros cursos afines a su carrera. La zoología brinda conocimientos, para poder analizar, comprender e interpretar procesos que favorecen en parte el desarrollo de un hábitat adecuado, además se estudia de manera general a las principales especies animales que causan daño o beneficio directo e indirectamente a las distintas especies animales y vegetales. Lo mismo que aquellas que por su naturaleza de hábito alimenticio contribuyen a la diseminación de frutos y semillas, también a las que se catalogan como plagas en los sistemas agroforestales.

A second-order dynamic subgrid-scale stress model

A second-order dynamic model based on the general relation between the subgrid-scale stress and the velocity gradient tensors was proposed. A priori test of the second-order model was made using moderate resolution direct numerical simulation date at high Reynolds number ( Taylor microscale Reynolds number R-lambda = 102 similar to 216) for homogeneous, isotropic forced flow, decaying flow, and homogeneous rotating flow. Numerical testing shows that the second-order dynamic model significantly improves the correlation coefficient when compared to the first-order dynamic models.