Papers by Albert Balfagon
Classical and Quantum Gravity, 2000
We use computational algorithms recently developed by us to study completely four index divergenc... more We use computational algorithms recently developed by us to study completely four index divergence free quadratic in Riemann tensor polynomials in GR. Some results are new and some other reproduce and/or correct known ones. The algorithms are part of a Mathematica package called Tools of Tensor Calculus (TTC)
Desarrollo y uso de un laboratorio virtual para el aprendizaje de la qu'imica
Recibido: 5 de febrero de 2007; aceptado: 15 de marzo de 2007 RESUMEN La utilización de simulacio... more Recibido: 5 de febrero de 2007; aceptado: 15 de marzo de 2007 RESUMEN La utilización de simulaciones en los procesos de enseñanza-aprendizaje es un área llena de oportunidades para la mejora educativa. En este trabajo, se presenta el IQSLabvirt un laboratorio virtual desarrollado en el Institut Químic de Sarrià y que consiste en la versión actual en un conjunto de siete prácticas virtuales (oscilaciones, valoración ácido-base, análisis cualitativo, colorimetría, preparación de disoluciones, cromatografía de capa fina y control estadístico de procesos) que incorporan problemas estructurados y capacidades evaluativas. Dos de estas prácticas virtuales han sido usadas en sendas pruebas piloto obteniéndose una opinión favorable de los alumnos en cuanto a motivación y percepción de aprendizaje. Los resultados de estas investigaciones también se presentan en esta comunicación. Palabras clave: Didáctica de la química. Educación. Laboratorio virtual. Enseñanza asistida por ordenador. Simulación.
Afinidad, 2007
Este trabajo se encuadra dentro del denominado Laboratorio Virtual, un proyecto encaminado a simu... more Este trabajo se encuadra dentro del denominado Laboratorio Virtual, un proyecto encaminado a simular practicas de laboratorio como herramienta de apoyo educativo. Se presenta una practica que simula choques entre dos particulas, en la que se pueden realizar diferentes ejercicios y variar los datos iniciales, desarrollada en lenguaje Microsoft3 Visual Basic, que permite evaluar mediante unos ejercicios el aprendizaje del alumno en estos temas
Rainich theory applied to m-rank tensors in n-dimensions
Virtual laboratory for the study of collisions
Afinidad -Barcelona-
This work is framed in the denominated Virtual Laboratory, a project oriented to simulate laborat... more This work is framed in the denominated Virtual Laboratory, a project oriented to simulate laboratory practices as a tool of educative support. A practice that simulates collisions between two particles and developed in Microsoft® Visual Basic is presented. In this practice is possible to carry out a variety of exercises with different initial conditions and it allows to evaluate the learning of the student in this subjects.
Laboratorio virtual para el estudio de colisiones
Cosmological Equations for Interacting Energies
In this paper the coupling between dark energy and the other components of the cosmological fluid... more In this paper the coupling between dark energy and the other components of the cosmological fluid has been studied. Firstly, it will be shown that the application of general cosmological equations, deduced by the authors in a previous work, to the known data of the Abell cluster A586 using the Layzer-Irvine theory gives similar results compared to the work of other authors. The aforesaid method present some problems: the application of an approximate theory (Layzer-Irvine theory), it has only one experimental datum and finally, it gives results that are a bit difficult to admit considering a physical reasoning. In order to avoid the above-mentioned problems, a way to study the coupling of dark energy with other Universe components has been shown. The results obtained have a sensible physical behavior. They also fix the required functionality of the product $w_\Lambda \Omega_\Lambda$ in order to verify the main known properties of the Universe's behavior. Finally, these results ...
Virtual laboratory for the study of collisions
Afinidad -Barcelona-
This work is framed in the denominated Virtual Laboratory, a project oriented to simulate laborat... more This work is framed in the denominated Virtual Laboratory, a project oriented to simulate laboratory practices as a tool of educative support. A practice that simulates collisions between two particles and developed in Microsoft® Visual Basic is presented. In this practice is possible to carry out a variety of exercises with different initial conditions and it allows to evaluate the learning of the student in this subjects.
In this paper the coupling between dark energy and the other components of the cosmological fluid... more In this paper the coupling between dark energy and the other components of the cosmological fluid has been studied. Firstly, it will be shown that the application of general cosmological equations, deduced by the authors in a previous work, to the known data of the Abell cluster A586 using the Layzer-Irvine theory gives similar results compared to the work of other authors. The aforesaid method present some problems: the application of an approximate theory (Layzer-Irvine theory), it has only one experimental datum and finally, it gives results that are a bit difficult to admit considering a physical reasoning. In order to avoid the abovementioned problems, a way to study the coupling of dark energy with other Universe components has been shown. The results obtained have a sensible physical behavior. They also fix the required functionality of the product wΛΩΛ in order to verify the main known properties of the Universe's behavior. Finally, these results permit to make predictions about a set of different cosmological properties.
We are presenting an algorithm capable of simplifying tensor polynomials with indices when the bu... more We are presenting an algorithm capable of simplifying tensor polynomials with indices when the building tensors have index symmetry properties. These properties include simple symmetry, cyclicity and those due to the presence of covariant derivatives. The algorithm is part of a Mathematica package called Tools of Tensor Calculus (TTC)[web address:
In an earlier paper ͓P. Castellví, X. Jaén, and E. Llanta, Comput. Phys. 9, 3 ͑1995͔͒ we presente... more In an earlier paper ͓P. Castellví, X. Jaén, and E. Llanta, Comput. Phys. 9, 3 ͑1995͔͒ we presented the capabilities of TTC ͑Tools of Tensor Calculus, a Mathematica package, see http:// baldufa.upc.es/ttc͒ when inputs are made in index notation. In that article inputs were merely an effective way to indicate explicit operations to be performed on tensors. Here we describe the way TTC operates with index notation at a symbolic level, that is, when inputs and outputs are expressed in index notation and tensors are not explicitly declared. The operations are performed only at a symbolic level. This is not just an appearance of symbolic computing supplemented with a limited collection of rules. TTC makes algorithm simplifications on symbolic indexed expressions while using the symmetry properties of tensors.
La utilización de simulaciones en los procesos de enseñanza-aprendizaje es un área llena de oport... more La utilización de simulaciones en los procesos de enseñanza-aprendizaje es un área llena de oportunidades para la mejora educativa. En este trabajo, se presenta el IQSLabvirt un laboratorio virtual desarrollado en el Institut Químic de Sarrià y que consiste en la versión actual en un conjunto de siete prácticas virtuales (oscilaciones, valoración ácido-base, análisis cualitativo, colorimetría, preparación de disoluciones, cromatografía de capa fina y control estadístico de procesos) que incorporan problemas estructurados y capacidades evaluativas. Dos de estas prácticas virtuales han sido usadas en sendas pruebas piloto obteniéndose una opinión favorable de los alumnos en cuanto a motivación y percepción de aprendizaje. Los resultados de estas investigaciones también se presentan en esta comunicación.
Recibido: 1 de febrero de 2007; aceptado 15 de marzo de 2007 RESUMEN Este trabajo se encuadra den... more Recibido: 1 de febrero de 2007; aceptado 15 de marzo de 2007 RESUMEN Este trabajo se encuadra dentro del denominado Laboratorio Virtual, un proyecto encaminado a simular prácticas de laboratorio como herramienta de apoyo educativo. Se presenta una práctica que simula choques entre dos partículas, en la que se pueden realizar diferentes ejercicios y variar los datos iniciales, desarrollada en lenguaje Microsoft ® Visual Basic, que permite evaluar mediante unos ejercicios el aprendizaje del alumno en estos temas.
Desarrollo y uso de un laboratorio virtual para el aprendizaje de la qu'imica
Tools of tensor Calculus Mathematica package
TTC is a Mathematica package for doing tensor and exterior calculus on differentiable manifolds. ... more TTC is a Mathematica package for doing tensor and exterior calculus on differentiable manifolds. It can be of interest to the scientist working on any field where tensor calculus is needed. TTC can also be interesting for teaching purposes.
TTC is a Mathematica package for doing tensor and exterior calculus on differentiable manifolds. ... more TTC is a Mathematica package for doing tensor and exterior calculus on differentiable manifolds. It can be of interest to the scientist working on any field where tensor calculus is needed. TTC can also be interesting for teaching purposes.
TTC: Symbolic tensor calculus with indices
Computers in Physics, 1998
International Journal of Cosmetic Science, 2010
Avec les données obtenues du DOE, on a confronté les algorithmes des moindres carrés (Least Mean ... more Avec les données obtenues du DOE, on a confronté les algorithmes des moindres carrés (Least Mean Square, LMS) et des réseaux de neurones artificiels (Artificial Neural Networks, ANN) pour obtenir une équation (ou modèle) qui puisse justifier la viscosité de la crème. Les calculs out démontré que les ANN sont la meilleure méthode pour ajuster un modèle aux données expérimentales, afin de prédire la propriété dans l'intervalle de concentrations utilisé dans l'ensemble des essais.
Journal of Cosmology and Astroparticle Physics, 2009
In this paper we study a model of cosmic evolution, assuming that the different components of the... more In this paper we study a model of cosmic evolution, assuming that the different components of the universe could interact between them any time. An effective equation of state (EOS) for the universe has been used as well. A particular function for w, which gives a good agreement between our results and the experimental data, has been studied. Finally, the model obtained has been applied to different important cases.
Uploads
Papers by Albert Balfagon