Study of magnetic field effect on the specific heat and entropy in DyBa2Cu3O7-x

The change in the specific heat by the application of magnetic field up to 161 for high temperature superconductor system for DyBa2Cu3O7-x by Revaz et al. [23] is examined through the phenomenological Ginzburg-Landau(G-L) theory of anisotropic Type-II superconductors. The observed specific heat anomaly near T-c with magnetic field is explained qualitatively through the expression <Delta C > = (B-a/T-c) t/(1 - t)(alpha Theta(gamma)lambda(2)(m)(0)), which is the anisotropic formulation of the G-L theory in the London limit developed by Kogan and coworkers; relating to the change in specific heat Delta C for the variation of applied magnetic field for different orientations with c-axis. The analysis of this equation explains satisfactorily the specific heat anomaly near T-c and determines the anisotropic ratio gamma as 5.608, which is close to the experimental value 5.3 +/- 0.5given in the paper of Revaz et al. for this system. (C) 2010 Elsevier B.V. All rights reserved.

Which Narrative? The Case of the Narrative Subject in Fifteenth-Century Altarpieces

The development of the altarpiece towards the end of the late medieval period added a new decorous and conspicuously visual element to the church interior. The altarpiece became the prime location for iconic – i.e. non-narrative – images, but almost from the beginning narrative images were part of the altarpiece in the form of small-scale pictures placed underneath or next to an iconic image in the centre. In the fifteenth century the format of the altarpiece gradually changed, and simultaneously with the development of the unified picture field some new narrative subjects began to appear on the central panel as the main subject of the altarpiece. During the course of the fifteenth century, narrative subjects became increasingly frequent and accepted subjects for altarpieces. In this article I will focus on the problem of the narrative altarpiece, a seeming contradiction of terms. As narrative subjects were transferred from their usual location to the central field of the altarpiece, traditionally reserved for the iconic image, the narrative was included in a new context and expected to assume the function of the altarpiece. How did a narrative image function in this context, and what kind of audience did it serve? Since the questions involved in the issue are complex, I will focus on the biblical narrative of The Visitation as a case study, and use two well-known Florentine altarpieces from the fifteenth century as examples of the interpretative choices open to the viewers of these altarpieces.

Narratives of Travel and the Travelling Concept of Narrative: Genre Blending and the Art of Transformation

In this article I shall argue that understandings of what constitutes narrative, how it functions, and the contexts in which it applies have broadened in line with cultural, social and intellectual trends which have seen a blurring, if not the dissolution, of boundaries between ‘fact’ and ‘fiction’; ‘literary’ and ‘non-literary’ narrative spaces; history and story; concepts of time and space, text and image, teller and tale, representation and reality.To illustrate some of the ways in which the concept of narrative has travelled across disciplinary and generic boundaries, I shall look at The Art of Travel (de Botton 2003), with a view to demonstrating how the blending of genres works to produce a narrative that is at once personal and philosophical; visual and verbal; didactic and poetic. I shall show that such a text constitutes a site of interrogation of concepts of narrative, even as it depends on the reader’s ability to narrativize experience.

The traditionalism-inclusionism controversy in special education : a conceptual analysis

The aim of this study has been to challenge or expand the present views on special education. In a series of six articles this thesis will directly or indirectly debate questions relating to inclusive and exclusive mechanisms in society. It is claimed that the tension between traditionalism and inclusionism within special education may harm the legitimation of special education as a profession of the welfare state. The articles address the relationship between these two approaches. The traditionalism-inclusionism controversy is partly rooted in different ways of understanding the role of special education with respect to democracy. It seems, however, that the traditionalism-inclusionism controversy tends to lead researchers to debate paradigmatic positions with each other than to develop alternative strategies for dealing with the delicate challenge of the differences within education. ---- There are three major areas of this discussion. The first part presents the theory of research programmes as a way of describing the content, the possibilities, and the problems of the different approaches. The main argument is that the concept of research programmes more clearly emphasizes the ethical responsibilities involved in research within the field of special education than does the paradigmatic approach. The second part considers the social aspects of the debate between traditionalism and inclusionism from different perspectives. A central claim made is that the work seen within special education must be understood as a reaction to the social and political world that the profession is part of, and that this also is part of a specific historical development. Even though it is possible to claim that the main aim for special education is to help people that are looked at as disabled or feel disabled, it is also necessary to understand that the profession is highly constrained by the grand narrative of the welfare state and the historical discourse that this profession is part of. The third part focuses on a central aspect of special education: the humanistic solutions towards people who are left behind by ordinary education. The humanistic obligation for special education is part of the general aim of the welfare state to provide an education for a democratic and an inclusive society. This humanistic aim and the goal to offer an education for democracy seem therefore, to dominate the understanding of how special education works.

PIV studies of large scale structures in the near field of small aspect ratio elliptic jets

The near flow field of small aspect ratio elliptic turbulent free jets (issuing from nozzle and orifice) was experimentally studied using a 2D PIV. Two point velocity correlations in these jets revealed the extent and orientation of the large scale structures in the major and minor planes. The spatial filtering of the instantaneous velocity field using Gaussian convolution kernel shows that while a single large vortex ring circumscribing the jet seems to be present at the exit of nozzle, the orifice jet exhibited a number of smaller vortex ring pairs close to jet exit. The smaller length scale observed in the case of the orifice jet is representative of the smaller azimuthal vortex rings that generate axial vortex field as they are convected. This results in the axis-switching in the case of orifice jet and may have a mechanism different from the self induction process as observed in the case of contoured nozzle jet flow.

A pulsed field gradient spin echo NMR spectrometer for diffusion coefficient measurements

A pulsed field gradient spin echo NMR spectrometer has been assembled by interfacing a programmable pulse generator and a data acquisition system designed and fabricated in our laboratory with other imported units. Calibration results of the magnetic field gradients are presented.

Field induced spin reorientation transition in epitaxial La0.5Sr0.5CoO3 films

Strained epitaxial La0.5Sr0.5CoO3 films are grown on LaAlO3 substrate. Structural, electrical,and magnetic measurements were carried out. Out of plane lattice parameter of the film undergoes compressive strain and the coercivity is enhanced. The zero field cooled (ZFC) magnetization curve for a field applied parallel to the film plane shows a jump, which suggests a spin reorientation transition (SRT), while ZFC magnetization for a field applied perpendicular to the film plane is featureless. This jump in magnetization is shifted to higher temperatures when the magnetic field is reduced. The SRT is attributed to the strain in the film. (C) 2010 Elsevier B.V. All rights reserved.

Development of twist in an emerging magnetic flux tube by poloidal field accretion

Aims. Following an earlier proposal for the origin of twist in the magnetic fields of solar active regions, we model the penetration of a wrapped up background poloidal field into a toroidal magnetic flux tube rising through the solar convective zone.Methods. The rise of the straight, cylindrical flux tube is followed by numerically solving the induction equation in a comoving Lagrangian frame, while an external poloidal magnetic field is assumed to be radially advected onto the tube with a speed corresponding to the rise velocity.Results. One prediction of our model is the existence of a ring of reverse current helicity on the periphery of active regions. On the other hand, the amplitude of the resulting twist depends sensitively on the assumed structure ( diffuse vs. concentrated/intermittent) of the active region magnetic field right before its emergence, and on the assumed vertical profile of the poloidal field. Nevertheless, in the model with the most plausible choice of assumptions a mean twist comparable to the observations results.Conclusions. Our results indicate that the contribution of this mechanism to the twist can be quite significant, and under favourable circumstances it can potentially account for most of the current helicity observed in active regions.

On the alleged equivalence of certain field theories

Abstract. We critically examine some recent claims that certain field theories with and without boson kinetic energy terms are equivalent. We point out that the crucial element in these claims is the finiteness or otherwise of the boson wavefunction renormalisation constant. We show that when this constant is finite, the equivalence proof offered in the literature fails in a direct way. When the constant is divergent, the claimed equivalence is only a consequence of improper use of divergent quantities.

Nonsingular cosmological models: the massive scalar field case

The nonminimal coupling of a massive self-interacting scalar field with a gravitational field is studied. Spontaneous symmetry breaking occurs in the open universe even when the sign on the mass term is positive. In contrast to grand unified theories, symmetry breakdown is more important for the early universe and it is restored only in the limit of an infinite expansion. Symmetry breakdown is shown to occur in flat and closed universes when the mass term carries a wrong sign. The model has a naturally defined effective gravitational coupling coefficient which is rendered time-dependent due to the novel symmetry breakdown. It changes sign below a critical value of the cosmic scale factor indicating the onset of a repulsive field. The presence of the mass term severely alters the behaviour of ordinary matter and radiation in the early universe. The total energy density becomes negative in a certain domain. These features make possible a nonsingular cosm

The condensed nearest neighbor rule using the concept of mutual nearest neighborhood (Corresp.)

A two-stage iterative algorithm for selecting a subset of a training set of samples for use in a condensed nearest neighbor (CNN) decision rule is introduced. The proposed method uses the concept of mutual nearest neighborhood for selecting samples close to the decision line. The efficacy of the algorithm is brought out by means of an example.