Design for Additive Manufacturing: Tool Review and a Case Study

This paper aims to collect in a structured manner different computer-aided engineering (CAE) tools especially developed for additive manufacturing (AM) that maximize the capabilities of this technology regarding product development. The flexibility of the AM process allows the manufacture of highly complex shapes that are not possible to produce by any other existing technology. This fact enables the use of some existing design tools like topology optimization that has already existed for decades and is used in limited cases, together with other novel developments like lattice design tools. These two technologies or design approaches demand a highly flexible manufacturing system to be applied and could not be used before, due to the conventional industrial process limitations. In this paper, these technologies will be described and combined together with other generic or specific design tools, introducing the study case of an additive manufactured mechanical design of a bicycle stem

Diseño de un velero de concepto crucero-regata de 31 pies

El presente proyecto tiene como principal objetivo el desarrollo del diseño de una embarcación de vela de 31 pies de eslora según los requisitos propuestos por un cliente tipo. Se pretende, mediante la aplicación de los conocimientos adquiridos durante la carrera y la normativa vigente (en este caso la ISO), diseñar un velero que aún satisfaciendo las necesidades del cliente cumpla con los parámetros actuales que definen a este tipo de embarcaciones a nivel estético, de performance y funcionalidad. Se ha optado por un concepto de compromiso que permite adaptarse a un amplio espectro de planes de navegación como es el crucero-regata. Se trata de una embarcación que permite salidas de día y pequeñas estancias de fin de semana (concepto de crucero), y que a la vez permite obtener buenos resultados en regatas de club y regatas de corta-media distancia tipo "Ruta de la Sal". La principal motivación que lleva al desarrollo de este proyecto es el obtener al finalizar el mismo una guía sólida, puesto que el trabajo es tutelado por un profesor y profesional del sector, que permita afrontar de forma más experimentada una vida laboral ligada al diseño de embarcaciones de recreo

Collaborative tools: computer science students' skills versus software industry needs

Software companies encourage and further the use of collaborative tools and skills at the workplace in pursuit of the benefits of their use: they improve communication, productivity and efficiency, and competitiveness. Besides, undergraduate and graduate software engineering computing curricula recommend subjects related to effective cooperative working and group learning. In order to align industry needs and curricula recommendations, universities should provide students with the collaborative knowledge and skills that they will require on the labour market once they finish their degrees. In this scenario, we asked three questions: Are collaborative tools beneficial to software projects? Is it easier for students with knowledge and skills of collaborative tools to find a job? Do enterprises use collaborative tools as a marketing strategy for the recruitment process or are they really empowering their employees to use collaborative tools? This paper explores these questions. We devised a survey addressing the above questions, which was administered to 86 recent computer science graduates. We applied statistical techniques to analyse the responses. From the data gathered during the survey, we conclude that the expected benefits of the use of collaborative tools are in fact corroborated, students skilled in the use of collaborative tools do find it easier to get jobs and companies are not only looking for people with collaborative skills but also use collaborative tools in their routine work processes

Basalt Fiber Composites with Reduced Thermal Expansion for Additive Manufacturing

Fused filament fabrication (FFF) is gaining attention as an efficient way to create parts and replacements on demand using thermoplastics. This technology requires the development of new materials with a reliable printability that satisfies the requirement of final parts. In this context, a series of composites based on acrylonitrile styrene acrylate (ASA) reinforced with basalt fiber (BF) are reported in this work. First, several surface modification treatments are applied onto the BF to increase their compatibility with the ASA matrix. Then, once the best treatment is identified, the mechanical properties, coefficient of thermal expansion (CTE) and warping distortion of the different specimens designed and prepared by FFF are studied. It was found that the silanized BF is appropriate for an adequate printing, obtaining composites with higher stiffness, tensile strength, low CTE and a significant reduction in part distortion. These composites are of potential interest in the design and manufacturing of final products by FFF, as they show much lower CTE values than pure ASA, which is essential to successfully fabricate large objects using this technique

Paisajes de la alquimia en Narnia y Tierra Media. Análisis de los arquetipos de la fantasía de J.R.R.Tolkien y C.S.Lewis

Landscapes of alchemy in Narnia and Middle Earth. Analysis of the archetypes of the fantasy of J. R. R. Tolkien and C. S. Lewis This work analyses the archetypical principles that are representative and frequent within the fantasy of J. R. R. Tolkien and C. S. Lewis, whose adaptations to the big screen made a huge impact in the general audience and, in the case of The Lord of the Rings, had the critical acclaim after receiving a large number of awards from the Academy. Both factors lead us to explore the corners of the works of these authors that remained unapproached in the films, and due to that, we take them from the psychoanalytical theory of the collective unconscious and of the archetypes of Carl Gustav Jung. In this research, we inquire into the symbolism behind the alchemy, related to the transmission of knowledge through generations, and we find in the figure of the wizard and the component of magic paradigmatical patterns whose symbolism is identical or analogue. In accordance to these results, Jung’s assumptions describe this transgenerational process of transmission of values and knowledge, and the alchemist history shows how this transmission is done through a veiled code at an unconscious level. Keywords: Archetype, Symbolism, Alchemy, Psychoanalysis, Fantasy literature.  El presente trabajo analiza los principios arquetípicos de la fantasía de J.R.R. Tolkien y C.S. Lewis, cuya adaptación a la gran pantalla tuvo un fuerte impacto en el público generalista y, en el caso de la saga de El Señor de los Anillos, gozó del reconocimiento de la crítica al ser galardonada con copiosos premios de la Academia. Ambos factores nos llevan a explorar los rincones de las obras de estos autores que quedaron sin abordar en los filmes, y para ello partimos de la teoría psicoanalítica del inconsciente colectivo y de los arquetipos de Carl Gustav Jung. En esta investigación, indagamos en el simbolismo tras la alquimia, asociada al trasvase de conocimientos generacional, y hallamos en la figura del mago y el componente de la magia patrones paradigmáticos con significados idénticos o análogos. Asimismo, quedará patente que la teoría jungiana describe el proceso de transmisión de valores y saberes transgeneracional, y que la historia alquímica muestra cómo dicha transmisión se da con un código velado a nivel inconsciente. Palabras clave: Arquetipo, simbolismo, alquimia, psicoanálisis, literatura fantástica

La broma macabra que acecha al murciélago. Una interpretación arquetípica de Joker y Batman

Batman and the Joker are two of the most iconic characters, not only from the comic-book’s world, but also from pop culture. Created in 1939 and 1940 respectively, their presence in graphic novels and movies have been frequent until our days, with more than seven decades of stories behind. Precisely due to that, both their looks and personalities went through changes in order to adapt to the generational change of readers, but at the same time, there are elements than remain immutable over the years, or even were brought back. This duplicity makes the Joker and Batman the perfect subjects of study from the theory of archetypes of the psychoanalyst Carl Gustav Jung, who pondered about the motives for which some myths’ components stayed in the imaginary collective, whether many others fell into oblivion. Another postulate of Jung was the dichotomy of the Shadow and the Mask, that enables to cut deeper into the parasitic relationship between Batman and the Joker. Therefore, so as to comprehend the bases that inspired many writers to portray the madness of the Joker, we will analyse two sociohistorical sources about the representation of the mental instability: the Madman’s card of Tarot’s deck, and the satire Stultifera Navis (The Ship of the Fools).Batman y el Joker son dos de los personajes más icónicos, no solo del mundo del cómic, sino también de la cultura popular. Creados en 1939 y 1940 respectivamente, su presencia en historietas y películas ha seguido siendo recurrente hasta nuestros días, con más de siete décadas de historias a sus espaldas. Precisamente por ello, tanto su aspecto como su personalidad han experimentado cambios para adaptarse al relevo generacional de lectores, pero a su vez, existen elementos que han permanecido inmutables con el paso de los años, o incluso que se han retomado. Esta duplicidad convierte al Joker y a Batman en los perfectos objetos de estudio desde la teoría de los arquetipos del psicoanalista Carl Gustav Jung, quien reflexionó acerca de los motivos por los que algunos componentes de los mitos han quedado en el imaginario colectivo, mientras otros caían en el olvido. Otro postulado de Jung fue la dicotomía de la Sombra y la Máscara, que permite profundizar en la parasitaria relación entre Batman y el Joker. Asimismo, para comprender las bases de inspiración de muchos guionistas para retratar la locura del Joker, analizaremos dos fuentes sociohistóricas sobre la representación de la inestabilidad mental: la carta del Loco de la baraja del Tarot, y la sátira Stultifera Navis (La Nave de los Locos)

Radial Photonic Crystal Shells and Their Application as Resonant and Radiating Elements

Radial photonic crystals (RPCs) are a class of microstructured media that possess very particular electromagnetic features. Their properties are driven by radially dependent permittivity and permeability profiles that are also anisotropic. A two dimensional RPC structure is designed and analyzed in order to assess its principal characteristics. This is done through the study of the dispersion diagram of the periodic multilayered structure and also through the analysis of a finite size device. In the later case, research is performed in view of possible applications of RPCs as resonant devices and also when they are combined with line sources. Finally, a device with reduced complexity is designed and implemented by means of a microstructured resonator array. This device is numerically analyzed and the comparison of two independent models shows very good agreement. Potential use of RPCs as frequency and location sensors is pointed out.Carbonell Olivares, J.; Torrent Martí, D.; Sánchez-Dehesa Moreno-Cid, J. (2013). Radial Photonic Crystal Shells and Their Application as Resonant and Radiating Elements. IEEE Transactions on Antennas and Propagation. 61(2):755-767. doi:10.1109/TAP.2012.2225015S75576761

Large-activation-energy analysis of gaseous reacting flow in pipes

This paper analyzes the exothermic reaction of an initially cold gaseous mixture flowing with a moderately large Reynolds number along a cylindrical pipe with constant wall temperature. An overall irreversible reaction with an Arrhenius rate having a large activation energy is used for the chemistry description. The flow is chemically frozen in the cold entrance region, where the velocity evolves towards the Poiseuille profile as the gas temperature increases towards the wall value, ushering in a reaction stage during which the rate of heat transfer from the wall changes from positive to negative. The subsequent downstream evolution of the flow depends critically on the competition between the heat released by the chemical reaction and the heat-conduction losses to the wall, as measured by the Damkohler number 8, first introduced by Frank-Kamenetskii in his seminal analysis of thermal explosions in cylindrical vessels. For values of delta below the critical value delta &#61; 2 corresponding to the quasi-steady explosion limit, heat losses to the wall keep the gas temperature close to the wall value, so that the chemical reaction occurs slowly along the pipe in a flameless mode, which is analyzed to give an implicit expression for the streamwise reactant distribution. By way of contrast, for delta > 2 the slow reaction rates occur only in an initial ignition region, which ends abruptly when very large reaction rates cause a temperature runaway, or thermal explosion, at a well-defined location, whose computation must account for the temperature found at the end of the entrance region. The predictions of the large-activation-energy analyses, including ignition distances for delta > 2 and flameless reactant consumption rates for delta < 2, show good agreement with numerical computations of the reactive pipe flow for finite values of the activation energy.This work was supported by the Spanish MCINN through project # CSD2010-00011

Analysis of flexural wave cloaks

This work presents a comprehensive study of the cloak for bending waves theoretically proposed by Farhat et al. [see Phys. Rev. Lett. 103, 024301 (2009)] and later on experimentally realized by Stenger et al. [see Phys. Rev. Lett. 108, 014301 (2012)]. This study uses a semi-analytical approach, the multilayer scattering method, which is based in the Kirchoff-Love wave equation for flexural waves in thin plates. Our approach was unable to reproduce the predicted behavior of the theoretically proposed cloak. This disagreement is here explained in terms of the simplified wave equation employed in the cloak design, which employed unusual boundary conditions for the cloaking shell. However, our approach reproduces fairly well the measured displacement maps for the fabricated cloak, indicating the validity of our approach. Also, the cloak quality has been here analyzed using the so called averaged visibility and the scattering cross section. The results obtained from both analysis let us to conclude that there is room for further improvements of this type of flexural wave cloak by using better design procedures. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).This work has been supported by the Spanish Ministerio de Economia y Competitividad and the European Union Fondo Europeo para el Desarrollo Regional (FEDER) under Grant with Ref. TEC2014-53088-C3-1-R. We gratefully acknowledge Nicolas Stenger for providing us the parameters listed in Table I.Climente Alarcón, A.; Torrent Martí, D.; Sánchez-Dehesa Moreno-Cid, J. (2016). Analysis of flexural wave cloaks. AIP Advances. 6(12):121704-1-121705-16. https://doi.org/10.1063/1.4968611S121704-1121705-1661

Library of Selenocyanate and Diselenide Derivatives as In Vivo Antichagasic Compounds Targeting Trypanosoma Cruzi Mitochondrion

Chagas disease is usually caused by tropical infection with the insect-transmitted protozoan Trypanosoma cruzi. Currently, Chagas disease is a major public health concern worldwide due to globalization, and there are no treatments neither vaccines because of the long-term nature of the disease and its complex pathology. Current treatments are limited to two obsolete drugs, benznidazole and nifurtimox, which lead to serious drawbacks. Taking into account the urgent need for strict research efforts to find new therapies, here, we describe the in vitro and in vivo trypanocidal activity of a library of selected forty-eight selenocyanate and diselenide derivatives that exhibited leishmanicidal properties. The inclusion of selenium, an essential trace element, was due to the wellknown extensive pharmacological activities for selenium compounds including parasitic diseases as T. cruzi. Here we present compound 8 as a potential compound that exhibits a better profile than benznidazole both in vitro and in vivo. It shows a fast-acting behaviour that could be attributed to its mode of action: it acts in a mitochondrion-dependent manner, causing cell death by bioenergetic collapse. This finding provides a step forward for the development of a new antichagasic agent.Ministerio de Economia, Industria y Competitividad, grant number CSD2010–00065 and CTQ2017–90852-REDCConserjería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucia, grant number A-CTS-383-UGR18Institute of Tropical Health of University of Navarre (ISTUN)Caixa FoundationRoviralta and UbesolAlfonso Martín Escudero Foundatio