7 research outputs found
State-of-the-art of Heliostat Field Layout Algorithms and their Comparison
No full textAbstractIn this paper a complete review of the most relevant algorithms for the generation of heliostat field layouts is presented. For each of the reviewed algorithms, a description of the layout generation approach, all the input parameters required and the main formulation is provided. The algorithms have been compared for different scenarios covering a range of tower heights, heliostat sizes and acceptance angles (defining to what extent the resulting field is North configuration or surrounding). A robust methodology has been developed, which ensures a fair comparison of the algorithms by analysing the performance of optimized solar fields according to each layout generation method. For this, all the input parameters of each layout generation algorithm are optimized for each scenario prior to comparing the solar field performances. The main conclusion of the present study is that all the analysed layout generation algorithms lead to similar solar field efficiencies when compared for the considered scenarios once they are optimized. Further work is required to check if the algorithms also show similar efficiencies, or to what extent they are similar, when wider scenarios are considered (larger solar field powers, locations, etc.)
Universidad de Navarra = 0 CO2
No full textUn proyecto académico, realizado por alumnos de la Escuela de Arquitectura de la
Universidad de Navarra durante el curso 2008-2009, derivó en una ambiciosa actuación propositiva para
que en el Campus de la Universidad de Navarra en Pamplona se minimizaran las emisiones de CO2. Las
ideas propuestas incluyen acciones relacionadas con el transporte, la gestión del agua, la gestión de
residuos,… Es objeto de esta comunicación exponer la metodología seguida en el proyecto, así como los
principales resultados obtenidos en distintas áreas
A note on hyperplane sections of real algebraic sets
No full textThe author studies the size of the set of hyperplanes which meet a non- zero-dimensional algebraic set V over a real-closed ground field R. More precisely, let us denote by V\sb c the locus of central points of V, i.e., the closure, in the order topology of R\sp n, of the set of regular points of V. The author proves the following: There exists a linear isomorphism of R\sp n such that for every ``generic'' hyperplane H of R\sp n, either H meets V\sb c or its transform by meets V\sb c.Depto. de Álgebra, Geometría y TopologíaFac. de Ciencias MatemáticasTRUEpu
A Characterization Of Rational And Elliptic Real Algebraic-Curves In Terms Of Their Space Of Orderings
No full textLet K be a formally real field with space of orderings X(K). Then Aut(K) operates on X(K). K is said to have the ”dense orbits property” if for any x 2 X(K) the orbit of
x is dense in X(K). Fields with the dense orbits property were introduced by D. W.
Dubois and T. Recio in Contemp. Math. 8, 265-288 (1982; Zbl 0484.12003) under the name of Q1-fields. They were further studied by the author and T. Recio [J. Pure Appl.
Algebra 30, 237-246 (1983; Zbl 0533.12018)]. In the present paper the dense orbits property is studied for function fields of real algebraic varieties. So, let V be a real
algebraic variety over the field R of real numbers, R(V ) the function field of V. It is proved that Aut(R(V )) is infinite if R(V ) has the dense orbits property. If V is a curve then R(V ) has the dense orbits property if and only if V is a rational or elliptic curve.Depto. de Álgebra, Geometría y TopologíaFac. de Ciencias MatemáticasTRUEpu
Some new results on ordered fields
No full textThe author shows there is a non-Archimedean ordering of the field R(x, y), where x and y are algebraically independent over K, for which the identity is the only order-preserving automorphism.
The author proves the partly known result that the following statements about an ordered field K are equivalent: (1) each polynomial in K[x] satisfies the intermediate value theorem; (2) if f 2 K[x] and a < b, then f takes on its maximum value at some c 2 [a, b]; (3) K is real closed.
A (not necessarily ordered) field K is said to have the extension property if each automorphism of K(x), where x is transcendental over K, is an extension of an automorphism of K.
The author gives sufficient conditions for a field to have the the extension property. For example, a field has the extension property if, for some fixed integer n greater than two, each polynomial xn−ax−1, a 2 K, has a root in K.Depto. de Álgebra, Geometría y TopologíaFac. de Ciencias MatemáticasTRUEpu
Ordered fields with the dense orbits property
No full textFor a formally real field K let X(K) be the space of orderings.
The automorphism group Aut(K) of K operates on X(K).
K is said to have the ’dense orbits property’ (DOP) if for all 2 X(K) the orbit of is dense in X(K). The study of such fields, which was begun in D. W. Dubois and the second author [Contemp. Math. 8, 265-288 (1982; Zbl 0484.12003)], is continued here.
The main question considered is the behavior of the DOP under purely transcendental and under algebraic field extensions.Depto. de Álgebra, Geometría y TopologíaFac. de Ciencias MatemáticasTRUEpu
UvA-DARE (Digital Academic Repository) Link to publication Citation for published version (APA): Inclusive search for the charmless radiative decay of the b-quark (b L3 Collaboration
No full textGeneral rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 29 Jun 2019 Physics Letters B 317 ( 1993 ) We report on the search for the electromagnetic penguin decay b --* s7 at v~ ~ mz. We find no evidence for a signal and place an upper limit on the decay rate Br(b ~ s~,) < 1.2 × 10 -3 at 90% C.L
