13 research outputs found

    Diseño de controladores para el control de una caldera de vapor

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    I resumen en el presente trabajo se ha realizado el diseño del sistema de control de una caldera marina. En primer lugar, se ha descrito cuál es la planta a controlar y los objetivos del sistema de control. A partir de los datos del manual de una caldera marina real, se ha obtenido el modelo matemático multi-input multi-output que describe el comportamiento de la planta a nivel de presión, exceso de oxígeno y volumen de agua como respuesta a diferentes caudales de combustible, aire y agua, y a cambios en la demanda. Se han seleccionado los sensores y actuadores del sistema de control y también se han obtenido sus modelos en forma de función de transferencia. A partir de todos estos modelos se han diseñado tres controladores, uno para cada lazo principal (presión, exceso de oxígeno y volumen de agua). Los controladores se han diseñado en el lugar geométrico de las raíces de evans con ayuda de la herramienta sisotool, lo que ha permitido ajustar los valores de sobreimpulso y velocidad de respuesta de cada variable a controlar. A fin de eliminar el acoplamiento entre lazos se ha implementado una corrección anticipativa o feedforward. finalmente, se han realizado pruebas de simulación con los controladores por medio de la herramienta simulink de matlab obteniendo resultados favorables

    Oceanus.

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    v. 34, no. 1 (1991

    A history of the University of Manchester, 1973-90

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    This is the second volume of a history of the University of Manchester since 1951. It spans seventeen critical years in which public funding was contracting, student grants were diminishing, instructions from the government and the University Grants Commission were multiplying, and universities feared for their reputation in the public eye. It provides a frank account of the University's struggle against these difficulties and its efforts to prove the value of university education to society and the economy. This volume describes and analyses not only academic developments and changes in the structure and finances of the University, but the opinions and social and political lives of the staff and their students as well. It also examines the controversies of the 1970s and 1980s over such issues as feminism, free speech, ethical investment, academic freedom and the quest for efficient management. The author draws on official records, staff and student newspapers, and personal interviews with people who experienced the University in very different ways. With its wide range of academic interests and large student population, the University of Manchester was the biggest unitary university in the country, and its history illustrates the problems faced by almost all British universities. The books will appeal to past and present staff of the University and its alumni, and to anyone interested in the debates surrounding higher education in the late twentieth century. A history of the University of Manchester, 1951-73 by Brian Pullan is also available from Manchester University Press

    Annual Report of the Board of Regents of the Smithsonian Institution, showing the operations, expenditures, and condition of the institution for the year 1879

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    Annual Report of the Smithsonian Institution. [1891] Research related to the American Indian; Indian mounds in Indiana and Florida; Indian shell-heaps and relics

    New Granada : twenty months in the Andes

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    Major Total Conversion in English: The Question of Directionality

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    This research investigates the directionality of major total conversion in English, where major total conversion is defined as the process and at the same time as the result of deriving a new lexical item by altering the part of speech of the base without marking the alteration overtly, as in the presumed pair dry – to dry. The question is whether there is a reliable strategy for deciding which member of a pair is the base and which member is the converted counterpart. Various attempts had been made to resolve the controversial directional issue, but the results have been inconsistent. The investigation aims to discover whether or not there exists a coherent notion about how to decide directionality by considering four factors assumed in the literature to reflect directionality. A large corpus of potential examples of major total conversion was collected to act as test materials. The four factors were compared for each major total conversion pair to see to what extent there was agreement among them. Results showed the factors did not agree to the expected extent. The findings are discussed in detail and it is claimed the inconsistencies can often be explained with recourse to a few general principles. In conclusion, on the whole the four factors considered are consistent with one another. In other words, the notion about how to determine directionality in major total conversion is coherent and can be maintained for English
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