Mecánica elástica, por A. Peña Boeuf. noventa años después

En el número 2427 de la Revista de Obras Públicas, correspondiente al año 1925, apareció un breve artículo1 escrito por un desconocido M. donde se glosaba la notable obra de Mecánica Elástica escrita por el reputado Ingeniero de Caminos, profesor de la Escuela Especial del Cuerpo, D. Alfonso Peña Boeuf. Pasados 90 años y, a la vez que recuperando el artículo, se referencia la importancia de dicho libro en la docencia y aprendizaje del cálculo estructural visto el prisma del tiempo discurridoPostprint (author's final draft

From Galileo to Navier and Clapeyron. The intuition of a genius versus engineering rigour

Galileo (1564-1642), in his well-known Discorsi (Galileo, 1638),briefly turning his attention to the fracture of a beam, starts an interesting discussion on the beam’s breakage as well as its location. Could the section and breaking point of a beam have been determined beforehand? Furthermore, is it specific to the material? What Galileo did was not merely challenge a physics problem, but the prevailing knowledge of his time: namely, Aristotelianism on one hand, and Nominalism on the other. As a matter of fact, must the breakage of an element be treated as a universal or is it particular to a given material? The present essay aims to prove how Galileo, confronting the structural problem and bringing it into the realm of science, was not just raising a problem but, using Salviati’s words, he also established what actually takes place. Many years later, with the progress of physics, strength of materials and theory of structures, figures such as Claude Navier (1785-1836) and Benoît Clapeyron (1799-1864) confirmed once again that the Pisan turned out to be right. This article intends to combine technical fields such as strength of materials and theory of structures with others like the history of science and philosophy proper. A cooperative approach to these disciplines can be doubtlessly helpful to improve the knowledge, learning and teaching of their different curricula, giving the reader a global, holistic perspective.Objectius de Desenvolupament Sostenible::1 - Fi de la PobresaObjectius de Desenvolupament Sostenible::4 - Educació de QualitatObjectius de Desenvolupament Sostenible::16 - Pau, Justícia i Institucions SòlidesPostprint (published version

Com les TIC poden ajudar a l'ensenyament de la història de la ciència

L’objectiu de la present comunicació fora presentar, dins la temàtica de les TIC en la incorporació de la història de la ciència a l’ensenyament, com l’ús d’aquestes eines pot ajudar a mostrar a l’alumnat –acostumat sens dubte a aquest tipus de tecnologies– proposicions o formulacions fetes segles enrere. Aquesta implementació pot anar acompanyada en paral·lel, a l’aula, de les formulacions teòriques (de pissarra) de matèries com la física, la mecànica i fins i tot d’altres com podria ser la filosofia.Postprint (author's final draft

The vierendeel truss: past and present of an innovative typology

In the late 19th century, Belgian engineer Jules Arthur Vierendeel registered the patent for a new type of beam. This would be later on better known as the Vierendeel truss. It is characterized by the frame’s lack of diagonal members, something which would appear to contradict conditions of steadiness and balance, along with its notable deformation and difficult calculation, caused technicians in his time to be skeptical about its applicability. Nevertheless, its application surged in popularity during the 20th century, being used both in civil engineering and architecture. What are the advantages of the Vierendeel truss as compared to other types, such as diagonal trusses? In this article, the Vierendeel typology will be introduced along with its main features, its calculation as well as its implementation in civil engineering and architectural works.Postprint (published version

Children immigration in the catalan parliamentary debate : the empty set

Catalonia has received an unprecedented number of unaccompanied foreign children throughout the past decades, most of them from Morocco. This new form of migration has had a significant effect on the way that Children Welfare Services in Catalonia have been rearranged at different levels. Yet, the administrative reforms were not matched by a parallel substantive debate in Parliament. By analyzing a textual corpus of parliamentary texts, the article concludes that the set of parliamentary activities covering the issue of unaccompanied children contains no elements to ground a substantial political debate around it.Cataluña ha recibido un número sin precedentes de menores no acompañados durante las últimas décadas, la mayoría de ellos procedentes de Marruecos. Esta nueva forma de migración ha tenido un impacto significativo en la posterior reorganización de los Servicios de Atención a la Infancia en Cataluña. Sin embargo, las reformas administrativas se llevaron a cabo sin un debate paralelo de fondo en el Parlamento. Mediante el análisis de un corpus textual de los textos parlamentarios, el artículo concluye que el conjunto de las actividades parlamentarias relacionadas con la llegada de menores no acompañados carece de los elementos que permiten generar un debate político de fondo

Theoretical view on the origin and implications of structural distortions in polyoxometalates

Structural features of polyoxometalates (POMs) —versatile inorganic clusters of academic and technological interest— are discussed in the present article. POMs are, in general, very regular structures presenting a high symmetry in most cases. Distortions are, however, important for some electronic and magnetic properties. We herein discuss some particular geometric features that are crucial for the theoretical treatment and comprehension of well-known experimental phenomena. For instance, we have been able to understand and rationalize the geometrical distortions present in molybdenum POMs. Moreover, we can affirm that these geometrical distortions are caused by a pseudo Jahn Teller effect. In what concerns NMR chemical shifts, we present a discussion on the importance of geometry for the correct description of the signals and the key role played by the interatomic distances. Finally, a study on the adsorption of Keggin clusters on silver surfaces shows how the POM structure looses its regular shape to adapt to that new situation

L'Evolució dels mètodes de càlcul d'estructures durant el segle XX: dels mètodes gràfics a la irrupció dels computadors

The methods of calculation used in engineering, and specifically in structural design, have experienced a great development throughout the 20th century. From the manual methodologies to the present systems, mainly based on computer calculations, they have increased of unimaginable way the calculation capacity, as well as the precision, reliability and speed of calculation. The methods at the beginning of the century, that followed the previous graphical methods, with which they coexisted a long time, gave rise to iterative systems for solving equations. These methodologies evolved with the appearance of first computers, and the increase of the capacity of calculation, memory and speed, lead to an increase of the degree of sophistication and complexity of the used methods. In this article the basic characteristics of the evolution of the methods of analysis of structures and its implications for the professional and educational world are exposed. This evolution is exemplified through three significant methods: the graphical methods, the Cross method and the Finite Element Metho