Contacto cultural y tradiciones fundacionales en la formación de profesores de Física de la UNLP

El trabajo refiere a una investigación efectuada por la autora acerca de los orígenes de la formación de profesores de Física en el contexto de la política institucional inaugural de la Universidad Nacional de La Plata entre los años 1906 y 1920. Centra en los aportes del Instituto de Física, uno de los ámbitos de recepción de la tradición alemana considerado fundamental para la inserción de la ciencia paradigmática del progreso. En este período se despliega una política universitaria de amplio cometido fundada en el entrelazamiento de diversos fundamentos teóricos y experienciales. Se plasmó un proyecto integral y sistemático de formación científica y profesional, extensión e investigación, según los cánones de la época. La formación de profesores de Física, parte de esa matriz fundacional, constituyó un espacio curricular de contacto cultural entre la tradición mencionada y la tradición pedagógica desenvuelta en la Sección Pedagógica de la Facultad de Ciencias Jurídicas y Sociales en 1906, posteriormente Facultad de Ciencias de la Educación en 1914, y Facultad de Humanidades y Ciencias de la Educación en 1920. Los vínculos entablados evidenciaron tensiones entre el énfasis en lo académico propio de la tradición humbodltiana del Instituto de Física y los rasgos técnicos y normalizadores-disciplinadores basados en la psicología experimental de la institución humanística. El abordaje teórico - metodológico de carácter cualitativo recurrió al método de comparación constante. El estudio documental, en confrontación teórico - contextual, constituyó la técnica de obtención, análisis e interpretación de los datos.

La Mediación Pedagógica en la carrera de Profesorado de Educación Física desde la perspectiva de los actores involucrados [docentes, alumnos y docentes observadores] : Estudio descriptivo y comparativo para repensar la formación docente

El presente estudio de tipo de Descriptivo, Comparativo, No Experimental, intenta determinar cuáles son las alternativas de Mediación Pedagógica más utilizadas en las asignaturas correspondientes a la carrera de profesorado de Educación Física de la Facultad de Educación de la Universidad Juan Agustín Maza y en qué medida, estas alternativas son percibidas por docentes y alumnos, es decir, por los actores involucrados. Se realizó la observación de dos clases por cada docente titular de la carrera de Profesorado de Educación Física, cada una de ellas fue observada por dos docentes quienes se constituyeron como pares observadores, a su vez se realizó una encuesta a cada docente (sobre la autopercepción de la MP en clase) y por último se encuestó a veinte alumnos (sobre la percepción de la MP) de cada año del profesorado correspondientes al ciclo 2011-12. De esta manera se abordo el mismo objeto de estudio (MP) desde 3 perspectivas distintas. Para medir las diferencias entres las percepciones sobre la MP de cada uno de los actores involucrados (docentes, alumnos y docentes observadores) se utilizó la prueba estadística Anova. A partir de ella se determinó que existen diferencias estadísticamente significativas entre los valores de la autopercepción docente y la percepción de pares y alumnos. Además se observó que la MP en la Facultad de Educación según los docentes observadores y la percepción del alumno la MP es 'BUENA' y según la autopercepción que tienen los docentes es 'MUY BUENA'. Si analizamos a todos los actores involucrados en su conjunto podemos afirmar que la MP de la carrera de profesorado de educación física en ?BUENA?. Como conclusión podemos expresar que la valoración realizada fue en general ?BUENA? pero haciendo un análisis pormenorizado, existieron cátedras donde los valores obtenidos no fue el esperado. Por lo que se sugiere realizar capacitaciones docentes en relación a esta temática

A two-dimensional finite element model of front surface current flow in cells under non-uniform, concentrated illumination

A two-dimensional finite element model of current flow in the front surface of a PV cell is presented. In order to validate this model we perform an experimental test. Later, particular attention is paid to the effects of non-uniform illumination in the finger direction which is typical in a linear concentrator system. Fill factor, open circuit voltage and efficiency are shown to decrease with increasing degree of non-uniform illumination. It is shown that these detrimental effects can be mitigated significantly by reoptimization of the number of front surface metallization fingers to suit the degree of non-uniformity. The behavior of current flow in the front surface of a cell operating at open circuit voltage under non-uniform illumination is discussed in detail.

Theoretical Transition Probabilities, Oscillator Strengths and Radiative Lifetimes Of Levels In Pb IV

Transitionprobabilities and oscillatorstrengths of 176 spectral lines with astrophysical interest arising from 5d10ns (n = 7,8), 5d10np (n = 6,7), 5d10nd (n = 6,7), 5d105f, 5d105g, 5d10nh (n = 6,7,8), 5d96s2, and 5d96s6p configurations, and radiativelifetimes for 43 levels of PbIV, have been calculated. These values were obtained in intermediate coupling (IC) and using relativistic Hartree–Fock calculations including core-polarization effects. For the IC calculations, we use the standard method of least-square fitting from experimental energy levels by means of the Cowan computer code. The inclusion in these calculations of the 5d107p and 5d105f configurations has facilitated a complete assignment of the energy levels in the PbIV. Transitionprobabilities, oscillatorstrengths, and radiativelifetimes obtained are generally in good agreement with the experimental data.

Radiative properties for warm and hot dense matter

We will present calculations of opacities for matter under LTE conditions. Opacities are needed in radiation transport codes to study processes like Inertial Confinement Fusion and plasma amplifiers in X-ray secondary sources. For the calculations we use the code BiGBART, with either a hydrogenic approximation with j-splitting or self-consistent data generated with the atomic physics code FAC. We calculate the atomic structure, oscillator strengths, radiative transition energies, including UTA computations, and photoionization cross-sections. A DCA model determines the configurations considered in the computation of the opacities. The opacities obtained with these two models are compared with experimental measurements.

A new set of relativistic screening constants for the screened hydrogenic model

AnewRelativisticScreenedHydrogenicModel has been developed to calculate atomic data needed to compute the optical and thermodynamic properties of high energy density plasmas. The model is based on anewset of universal screeningconstants, including nlj-splitting that has been obtained by fitting to a large database of ionization potentials and excitation energies. This database was built with energies compiled from the National Institute of Standards and Technology (NIST) database of experimental atomic energy levels, and energies calculated with the Flexible Atomic Code (FAC). The screeningconstants have been computed up to the 5p3/2 subshell using a Genetic Algorithm technique with an objective function designed to minimize both the relative error and the maximum error. To select the best set of screeningconstants some additional physical criteria has been applied, which are based on the reproduction of the filling order of the shells and on obtaining the best ground state configuration. A statistical error analysis has been performed to test the model, which indicated that approximately 88% of the data lie within a ±10% error interval. We validate the model by comparing the results with ionization energies, transition energies, and wave functions computed using sophisticated self-consistent codes and experimental data.

Determination of the average ionization and thermodynamic regimes of xenon plasmas with an application to the characterization of blast waves launched in xenon clusters

Radiative shock waves play a pivotal role in the transport energy into the stellar medium. This fact has led to many efforts to scale the astrophysical phenomena to accessible laboratory conditions and their study has been highlighted as an area requiring further experimental investigations. Low density material with high atomic mass is suitable to achieve radiative regime, and, therefore, low density xenon gas is commonly used for the medium in which the radiative shock propagates. In this work the averageionization and the thermodynamicregimes of xenonplasmas are determined as functions of the matter density and temperature in a wide range of plasma conditions. The results obtained will be applied to characterize blastwaveslaunched in xenonclusters

Sostenibilidad energética a largo plazo. El papel de la fusión nuclear

En este artículo se realiza una disertación sobre la sostenibilidad energética y la contribución de las diferentes energías a ella, analizando con especial énfasis el papel que desempeña la fusión nuclear en el desarrollo sostenible

Potential common radiation problems for components and diagnostics in future magnetic and inertial confinement fusion devices

This work aims at identifying commonpotentialproblems that futurefusiondevices will encounter for both magnetic and inertialconfinement approaches in order to promote joint efforts and to avoid duplication of research. Firstly, a comparison of radiation environments found in both fusion reaction chambers will be presented. Then, wall materials, optical components, cables and electronics will be discussed, pointing to possible future areas of common research. Finally, a brief discussion of experimental techniques available to simulate the radiation effect on materials is included

Experimental Model to estimate shading losses on PV arrays

This paper presents a simple mathematical model to estimateshadinglosses on PVarrays. The model is applied directly to power calculations, without the need to consider the whole current–voltage curve. This allows the model to be used with common yield estimation software. The model takes into account both the shaded fraction of the array area and the number of blocks (a group of solar cells protected by a bypass diode) affected by shade. The results of an experimental testing campaign on several shaded PVarrays to check the validity of model are also reported.

Importance of Nuclear Data Uncertainties in Criticality Calculations

To study the propagation of the uncertainty from basic data across different scale and physics phenomena -> through complex coupled multi-physics and multi-scale simulations

Impact of Nuclear Data Uncertainties in the Phase-1B Benchmark

Accurate control over the spent nuclear fuel content is essential for its safe and optimized transportation, storage and management. Consequently, the reactivity of spent fuel and its isotopic content must be accurately determined.

Intermediate band materials for more efficient solar energy use: quantum modelling and experimental realizations

The intermediate band (IB) solar cell (Fig. 1) has been proposed [1] to increase photovoltaic efficiency by a factor above 1.5, based on the absorption of two sub-bandgap photons to promote an electron across the bandgap. To realize this principle, that can be applied also to obtain efficient photocatalysis with sunlight, we proposed in recent years several materials where a metal or heavy element, substituting for an electropositive atom in a known semiconductor that has an appropriate band gap width (around 2 eV), forms inside the gap the partially filled levels needed for this aim

An overview on armor research for the laser fusion project HiPER

During the current preparatory phase of the European laser fusion project HiPER, an intensive effort has being placed to identify an armour material able to protect the internal walls of the chamber against the high thermal loads and high fluxes of x-rays and ions produced during the fusion explosions. This poster addresses the different threats and limitations of a poly-crystalline Tungsten armour. The analysis is carried out under the conditions of an experimental chamber hypothetically constructed to demonstrate laser fusion in a repetitive mode, subjected to a few thousand 48MJ shock ignition shots during its entire lifetime. If compared to the literature, an extrapolation of the thermomechanical and atomistic effects obtained from the simulations of the experimental chamber to the conditions of a Demo reactor (working 24/7 at hundreds of MW) or a future power plant (producing GW) suggests that “standard” tungsten will not be a suitable armour. Thus, new materials based on nano-structured W and C are being investigated as possible candidates. The research programme launched by the HiPER material team is introduced.

New simulations to qualify eutectic lithium-lead as breeder material

Pb17Li is today a reference breeder material in diverse fusion R&D programs worldwide. One of the main issues is the problem of liquid metals breeder blanket behavior. The knowledge of eutectic properties like optimal composition, physical and thermodynamic behavior or diffusion coefficients of Tritium are extremely necessary for current designs. In particular, the knowledge of the function linking the tritium concentration dissolved in liquid materials with the tritium partial pressure at a liquid/gas interface in equilibrium, CT =f(PT ), is of basic importance because it directly impacts all functional properties of a blanket determining: tritium inventory, tritium permeation rate and tritium extraction efficiency. Nowadays, understanding the structure and behavior of this compound is a real goal in fusion engineering and materials science. Atomistic simulations of liquids can provide much information; not only supplementing experimental data, but providing new tests of theories and ideas, making specific predictions that require experimental tests, and ultimately helping to a deeper understanding