Adaptive control of a solar furnace for material testing

IFAC Adaptive Systems in Control and Signal Processing. Glasgow. Scotland. UK. 26/08/1998This paper presents an adaptive control system for controlling the temperature of a solar furnace, which is a high solar concentrating facility made up of heliostats tracking the sun and reflecting solar radiation onto a static parabolic concentrating system at the focal spot of which a high percentage of the solar energy collected by the collector system is concentrated in a small area. A large attenuator (shutter) placed between the collector system and the concentrator serves to control the amount of solar energy used for heating the samples placed at the focal spot. The paper shows the results obtained in the application of adaptive PI controllers to a solar furnace, incorporating feedforward action, anti-windup and slew rate constraint handling mechanisms

Violencia, neoplatonismo y aristotelismo en “La Aurora en Copacabana”

En este ensayo estudio las diferentes formas en que se manifiesta la violencia en “La Aurora en Copacabana” de Calderón y su relación con dos visiones del mundo que están en conflicto durante todo el siglo XVII: la neoplatónica, personificada en la figura de Yupangui y la aristotélica, trazada en específicos momentos de la primera jornada y, sobre todo, en la tercera. Expongo cómo el intento de sacrificio de Guacolda, la violencia del lenguaje (incomunicación entre indios y españoles) y el desplazamiento de los nombres de los protagonistas por nombres españoles (Yupangui y Guacolda cambian sus nombres por Francisco y María) forman el hilo conductor y el marco en donde se produce el conflicto entre la visión aristotélica y neoplatónica de la representación. Aunque Calderón parece decantarse por el neoplatonismo (para favorecer el tema de la fe cristiana), sin embargo, la misma representación de la violencia en ésta y otras obras como el “Médico de su honra” o “El pintor de su deshonra” plantea un conflicto continuo por la búsqueda de la perfección a través de las relaciones humanas y de la representación dramática

New data from Orihuela and Callosa Mountains (Betic Internal Zone, Alicante, SE Spain). Implications for the “Almágride Complex” controversy

In this paper, we present the results of the stratigraphic and structural study of the Orihuela and Callosa Mountains (Alicante province, SE Spain), belonging to the Internal Betic Zone. The terrains cropping out in this area had been assigned by previous authors to the Ballabona-Cucharón Complex, lately redefi ned as the Almágride Complex. New data afforded in this work lead us to propose a new stratigraphic succesions, structural division, and geodynamic evolution. We also assign both mountains ranges to the lower Alpujarride Complex, confi rming that the Almágride Complex is not a singular element of the Betic Cordillera.En este trabajo presentamos los resultados del estudio estratigráfi co y estructural de las sierras de Orihuela y Callosa (provincia de Alicante, SE de España), pertenecientes ambas a la Zona Interna Bética. Estas sierras fueron asignadas por autores precedentes al Complejo Ballabona-Cucharón, más tarde redefi nido como Almágride. Los datos presentados en este trabajo nos llevan a proponer una nueva serie estratigráfi ca, división tectónica y evolución geodinámica del sector estudiado. Así mismo, asignamos las unidades reconocidas a la parte inferior del Complejo Alpujárride, confi rmando que el Complejo Almágride no debe ser considerado como elemento singular de la Zona Interna Bética

Transmission properties of a single metallic slit: From the subwavelength regime to the geometrical-optics limit

In this work we explore the transmission properties of a single slit in a metallic screen. We analyze the dependence of these properties on both slit width and angle of incident radiation. We study in detail the crossover between the subwavelength regime and the geometrical-optics limit. In the subwavelength regime, resonant transmission linked to the excitation of waveguide resonances is analyzed. Linewidth of these resonances and their associated electric field intensities are controlled by just the width of the slit. More complex transmission spectra appear when the wavelength of light is comparable to the slit width. Rapid oscillations associated to the emergence of different propagating modes inside the slit are the main features appearing in this regime.Comment: Accepted for publication in Phys. Rev.

Constructing Formally Verified Reasoners for the ALC Description Logic

AbstractDescription Logics are a family of logics used to represent and reason about conceptual and terminological knowledge. Recently, its importance has been increased since they are used as a basis for the Ontology Web Language (OWL) used for the Semantic Web. In previous work, we have developed in PVS a generic framework for reasoning in the ALC description logic, proving its termination, soundness and completeness. In this paper we present the construction, from the generic framework, of a formally verified generic tableau-based algorithm for checking satisfiability of ALC-concepts. We do it using a methodology of refinements to transfer the properties from the framework to the algorithm. We also obtain some verified reasoners from the algorithm by a process of instantiation

Sensitivity enhancement by increasing the nonlinear crystal length in second-order autocorrelators for ultrashort laser pulses measurement

A theoretical model for interferometric autocorrelation with long nonlinear crystal (input depleted) has been developed and applied to the measurement of the duration of ultrashort pulses. The phase-matching condition is assumed throughout pulse spectrum. The interferometric autocorrelation trace of a mode-locked fibre laser (20 nJ energy, 100 kW peak power, centred at 1595 nm) has been measured by employing a fibre interferometer to avoid misalignment effects and a BBO nonlinear crystal as long as 2 mm, in order to generate higher second-harmonic power. BBO crystal was used because it can keep the phase-matching condition throughout a wide spectrum around 1600 nm. By fitting the experimental measurements and computing according to the theoretical model exposed, it has been demonstrated that the autocorrelator sensitivity is clearly enhanced by increasing the nonlinear crystal length. A temporal duration of 0.18 ps has been obtained by fitting theoretical and experimental values

From Declarative Set Constraint Models to “Good” SAT Instances

On the one hand, Constraint Satisfaction Problems allow one to declaratively model problems. On the other hand, propositional satisfiability problem (SAT) solvers can handle huge SAT instances. We thus present a technique to declaratively model set constraint problems, to reduce them, and to encode them into ”good” SAT instances. We illustrate our technique on the well-known nqueens problem. Our technique is simpler, more expressive, and less error-prone than direct hand modeling. The SAT instances that we automatically generate are rather small w.r.t. hand-written instances

Extrusión del componente plástico de la copa acetabular sin luxación protésica: a propósito de un caso

Se present a un caso de extrusión del component e plástic o (polietileno) ocurrido en el transcurso del primer me s del postoperatorio en un pacient e que había sufrido un recambio del component e acetabular. Se destaca el hecho de que cursase de forma asintomática y de que no se acompañase de luxación de la prótesis.A case of disassembly of the polyethylene component of the acetabular cup acurred in a patient one mouth after revision surgery for loosening of a screwed acetabular cup is reported. Special emphasis is made in the asyntomati c clinic and on the no association with dislocation of the femoral component

Algebraic Solutions of the Multicomponent KP Hierarchy

It is shown that it is possible to write down tau functions for the $n$-component KP hierarchy in terms of non-abelian theta functions. This is a generalization of the rank 1 situation; that is, the relation of theta functions of Jacobians and tau functions for the KP hierarchy.Comment: 19 page

El vocabulario agrícola del «Diccionario de autoridades» (1770) autorizado con el «Libro de agricultura» de Alonso de Herrera

The reception of the Libro de Agricultura is examined in the second edition of the Diccionario de Autoridades. The academic review of the first repertoire caused amendments in those agricultural articles that were lemmatized and, as a result of this modification, were incorporated in the Alonso de Herrera’s authority in 1770. Simultaneously, the emptying of the geoponic treaty involved the addition of new entries under his authorization. The microstructural analysis of the amended articles demonstrates their readjustment in the notation, definition and Latin equivalents, as well as in Alonso de Herrera’s authority review to suit the lemmatized senses. The study of contexts that have been put forward, as well as the remodelled ones, after the comparison with the versions of Alonso de Herrera’s book, printed between 1513 and 1768, reveals the preferential use of the first editions to illustrate geoponic technicalities and the alteration of passages, particularly the parenthetical paragraph introduced to contextualize the quote.Se examina la recepción lexicográfica del Libro de agricultura en la segunda edición del Diccionario de autoridades. La revisión por parte de los académicos de su primer repertorio provocó enmiendas en aquellos artículos agrícolas lematizados, que, fruto de su remodelación, incorporan en 1770 la autoridad de Alonso de Herrera. Paralelamente, el vaciado del tratado geopónico supuso la adición de nuevas entradas con su autorización. El análisis microestructural de los artículos enmendados demuestra su reajuste en la marcación, definición y equivalentes latinos, así como en la revisión de la autoridad herreriana para corresponder con los sentidos lematizados. El estudio de los nuevos contextos alegados, así como de los remodelados, a partir del cotejo con las versiones del libro herreriano impresas entre 1513 y 1768, revela la utilización preferente de las primeras ediciones para ilustrar los tecnicismos geopónicos, así como la alteración de los pasajes, particularmente del inciso parentético introducido para contextualizar la cita