6,295 research outputs found

    Globalizations for partial (co)actions on coalgebras

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    In this paper, we introduce the notion of globalization for partial module coalgebra and for partial comodule coalgebra. We show that every partial module coalgebra is globalizable exhibiting a standard globalization. We also show the existence of globalization for a partial comodule coalgebra, provided a certain rationality condition. Moreover, we show a relationship between the globalization for the (co)module coalgebra and the usual globalization for the (co)module algebra.Comment: 31 page

    Multidisciplinary design and flight testing of a remote gas/particle airborne sensor system

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    The main objective of this paper is to describe the development of a remote sensing airborne air sampling system for Unmanned Aerial Systems (UAS) and provide the capability for the detection of particle and gas concentrations in real time over remote locations. The design of the air sampling methodology started by defining system architecture, and then by selecting and integrating each subsystem. A multifunctional air sampling instrument, with capability for simultaneous measurement of particle and gas concentrations was modified and integrated with ARCAA’s Flamingo UAS platform and communications protocols. As result of the integration process, a system capable of both real time geo-location monitoring and indexed-link sampling was obtained. Wind tunnel tests were conducted in order to evaluate the performance of the air sampling instrument in controlled nonstationary conditions at the typical operational velocities of the UAS platform. Once the remote fully operative air sampling system was obtained, the problem of mission design was analyzed through the simulation of different scenarios. Furthermore, flight tests of the complete air sampling system were then conducted to check the dynamic characteristics of the UAS with the air sampling system and to prove its capability to perform an air sampling mission following a specific flight path

    On partial (Co)actions on coalgebras : globalizations and some galois theory

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    Partial module coalgebra and partial comodule coalgebra are the dual notions of partial module algebra, and all these structures are close related. Partial module algebra was defined by Caenepeel and Janssen in [11] and developed in a certain direction by Alves and Batista in [1‚Äď3]. We are interested in some constructions made by Alves and Batista, namely: globalization for partial module algebras, a Morita context relating the invariant subalgebra and the partial smash product, and Galois theory. In this work, we introduce the notion of globalization for partial module coalgebra and for partial comodule coalgebra. We show that every partial module coalgebra is globalizable constructing a globalization, named standard. For the case of partial comodule coalgebra we need assume some kind of rationality condition to obtain a correspondent globalization. Moreover, for a partial comodule coalgebra, we construct a Morita-Takeuchi context relating the coinvariant coalgebra and the partial smash coproduct, and we define a Galois coextension and show some properties, relating the Galois coextension for partial comodule coalgebra with the Galois extension for partial coaction on algebras, extending results of Dascalescu, Raianu, and Zhang obtained in [20]

    La justicia del rey y los falsificadores de moneda en la Nueva Espa√Īa en el siglo XVIII

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    Dise√Īo y modelado de un manipulador serial redundante de siete grados de libertad, apto para efectuar una interacci√≥n f√≠sica segura entre humano y robot

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    En este proyecto se presenta el dise√Īo y modelado virtual de un manipulador serial con siete grados de libertad con el fin de generar antecedentes en la facultad de Ingenier√≠a mec√°nica en cuanto a la utilizaci√≥n de manipuladores redundantes, explorando su morfolog√≠a, comportamiento cinem√°tico y su posibilidad de construcci√≥n a bajos costos. Como resultado de este proyecto se obtiene un prototipo virtual modelado en Solidworks as√≠ como los modelos matem√°ticos de la cinem√°tica inversa y directa, aportes que servir√°n para la futura investigaci√≥n enfocada en generaci√≥n de trayectorias para la evasi√≥n de obst√°culos en un entorno colaborativo

    Tiempo y eternidad en el libro XI de Las Confesiones de San Agustín.

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    Tesis (Licenciado en Filosof√≠a)RESUMEN: El libro XI de las Confesiones de San Agustin, se presenta una pregunta que ha llamado la atenci√≥n por mucho tiempo a la filosof√≠a: "¬ŅQu√© es, pues, el tiempo? Si nadie me lo pregunta, lo s√©; si alguien me lo pregunta y quiero explicarlo, ya no lo s√©" (Confesiones, XI, 14, 17). Nuestro estudio aborda este problema introduciendo la reflexi√≥n acerca de la eternidad, segmento que Husserl aisla de su reflexi√≥n del tiempo. Sin negar esa exclusi√≥n realizada por parte de dicho autor, nosotros la introducimos, ya que nuestra preocupaci√≥n se centra en permanecer atento a las relaciones entre eternidad y tiempo que all√≠ son exploradas por san Agust√≠n. ¬ŅQu√© significaci√≥n puede tener esta tensi√≥n entre tiempo y eternidad para la comprensi√≥n de la experiencia humana del tiempo?, es la pregunta que nos guiara durante la extensi√≥n de nuestro estudio. Nuestro estudio estar√° en un primer capitulo centrado en explicitar el modo en que abordamos la reflexi√≥n entre eternidad y tiempo, para luego abordar el tema de la creaci√≥n que enmarca la reflexi√≥n de la eternidad y tiempo. Despu√©s en el segundo capitulo, se adentra en la problem√°tica del tiempo, atendiendo a las aportas que Agustin nos hace explicitas cuando se piensa al tiempo. √Čsta reflexi√≥n, nos conduce a tratar por separado en el cap√≠tulo tercero a la tesis resolutoria para las apor√≠as del tiempo que Agust√≠n nos ha presentado, la distentio animi es presentada en √©sta primera instancia. La distentio animi es profundizada en el cuarto capitulo, para tratar la filiaci√≥n de eternidad y tiempo distentio animi, con el objetivo de hacer presente el sentido que puede tener su consideraci√≥n de la eternidad para una comprensi√≥n de la experiencia humana del tiempo. Asumiendo dicha pregunta como la pregunta guia de nuestro estudio, cabe se√Īalar que √©ste se desarrollar√° esencialmente como un ejercicio de lectura que seguir√°, tanto analitica como interpretativamente, los desplazamientos m√°s significativos del libro en cuesti√≥n en lo que respecta al tratamiento de la problem√°tica resaltada. La puesta en relieve de estos desplazamientos nos permite proponer el ante dicho itinerario

    Third generation advanced high strength steels via ultrafast heating

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    Novel Axisymmetric Diffusion Bonded Recuperator for Gas Turbines

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    The small gas turbines systems, arbitrary categorized as microturbines (5-200 kW) and miniturbines (200-500 kW) are the current most economical solution for the distributed power generation market. The thermal efficiency of such microturbines without and with a recuperator is about 20 and 40% respectively, thus a recuperator is mandatory to reach higher cycle efficiencies. However, the recuperator accounts for about 25-30% of the turbine total cost and its temperature and pressure are constrained depending on the material and construction method, being the bottleneck of the improvement and advancement of this kind of power generation plant. Thus, the actual focus is to develop high performance recuperators able to withstand high temperatures and pressure at minimum cost. There are several different recuperators present on the market, each with their own heat transfer surface and manufacturing method, but all present drawbacks and are relatively old compared to the actual manufacturing methods. For instance, the rectangular offset strip fin geometry, which is one of the highest performance surfaces, is expensive to manufacture and weak to withstand temperature and pressure due to brazing requirements. Hence, in this thesis, a completely novel modular axisymmetric recuperator concept is proposed, joined by diffusion bonding technique, one of the current most advanced heat exchanger manufacturing methods. For the recuperator core, a novel heat transfer surface is proposed based in the rectangular offset strip fins, the thermal and hydraulic characteristics of which were determined experimentally. The devised heat transfer and pressure drop correlations show 85% agreement with the experimental data in the range of 500<3000. A code for the recuperator design, using entropy generation minimization, was developed to predict the recuperator performance and size the optimum recuperator core dimensions. The design code was validated with CFD which in turn was validated with experimental data. The heat transfer and pressure drop CFD results agreed the experimental data with deviation within 3.2% and 27.7%, respectively, and the design code agreed the CFD results with deviation within 0.9% and 11.9%, respectively. Four recuperator study cases for different turbine sizes, 100kW, 100kW_beta, 1250kW and 5000kW, were designed using the design code. The results show the proposed concept can achieve high effectiveness (~90%) with low pressure drop (<4%) with a volume compatible with the current recuperators. Furthermore, the novel recuperator concept has a list of advantages, which makes attractive its application on the future gas turbines, encouraging the research continuity of the proposed concept
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