[pt] O processo de lingotamento contínua de metais é simulado numericamente. Placas ou tarugos metálicos são produzidos continuamente, mantendo-se o escoamento do material através do molde. A frente de solidificação depende da velocidade de retirada de material e da refrigeração imposta na superfície do lingote. A posição da interface líquido-sólido e o campo de temperaturas na região sólida são determinados, e consideram-se os efeitos da velocidade na curvatura da interface. É analisado um modelo retangular bi-dimensional e a equação da energia é resolvida utilizando-se o método numérica de diferenças finitas das volumes de controle. Os resultados são comparados com soluções analíticas simplificadas onde a termo de transporte não foi considerado e mostram que o calar transportado pelo movimento de lingote tem influência significativa na forma da interface e em sua localização dentro do molde durante o processo. / [en] This work deals with a numerical simulation of the continuous casting process. This process is employed in the fabrication of metallic inguts. The position of the solid-liquid interface is determined together with the temperature field in the solid region. The research is facused on studying the effect of the withdrawal velocity on the interface position, aiming at accidental leakage preventien during the process. In this analysis, the sensible heat is taken into acceunt, in contrast to previous marks reported in the open literature. The present work employed a two-dimensional model. The energy equation was integrated in the rectangular domain by means of the finite-volume method. The liquid regions was at the fusion temperatures, whereas one of the side boundaries was strogly cooled to promote solidification. An algorithm was developed to determine the interface pesition and the domain length. Comparisons of this results obtained with the available solutions obtained excluding sensible heat showed that, depending upon the value of the withdrawal velocity, the sensible heat may or may not be negleted. The simulations was performed with the aid of a microcomputer of the IBM-PC/XT type, employing the Fortran language.

No description available.

Theoretical constructs latent in thoroughbass treatises of the 18th century can serve students of thoroughbass today. In the following work, I draw from Johann David Heinichen’s Der General-Bass in der Composition (1728), David Kellner’s Treulicher Unterricht im General-Baß (2nd edition, 1737), Johann Mattheson’s Der vollkommene Capellmeister (1739), Friedrich Wilhelm Marpurg’s Handbuch bey dem Generalbasse und der Composition, Carl Philipp Emanuel Bach’s Versuch über die wahre Art das Clavier zu spielen (part 2, 1762), and recent scholarship in the areas of Partimento theory, Musica Poetica, and early music theory in general, to demonstrate how the many thoroughbass figures can all be contextualized in an historically informed theoretical framework. In the first two chapters, (1) thoroughbass figures are analyzed as having an internal hierarchy of primary and auxiliary intervals, allowing chords to be understood both vertically and linearly; (2) chords are localized in the major and minor modes according to bass scale steps; and (3) the various contrapuntal procedures associated with dissonant chords used in both the strict style (stylus gravis) and freer styles (stylus luxurians communis and stylus luxurians theatralis) are analyzed as German musical-rhetorical figures. In chapter 3, these three theoretical constructs are used to organize an extensive collection of dissonant chord progressions derived from the aforementioned treatises of Heinichen, Mattheson, Marpurg, and Bach. In chapter 4, I draw from basic elements of partimento theory—namely cadences, sequences, and the Rule of the Octave (regola dell’ottava or règle de l’octave)—to construct a series of exercises; most of these exercises use a relatively strict four-part texture and are illustrated from multiple righthand starting positions to promote flexibility in the student. Finally, in chapter 5, practical matters of thoroughbass realization, namely pragmatic and expressive concerns, are discussed and illustrated with examples from many treatises of the 17th and 18th centuries.

These four sonatas of William Flackton (1709-1798) are probably the earliest collection of sonata literature written for the viola. They exist with a few other string sonatas from the Baroque period in England. It is essential to establish their place in English baroque music and to develop a performance milieu or stylistic preference that leads up to and lasts through the time span of Flackton's sonatas. The final tool to establish an interpretive plan will be to present a general analysis of the four sonatas with special emphasis on the D major sonata (opus 2, no. 4).

Not available

Not available / text

Die Kantate »La bella fiamma ò Tirsi« gehört zu den wenigen Werken aus einem umfangreichen OEuvre von 63 Kammerkantaten von Johann David Heinichen, deren Entstehungsort und Datierung überliefert sind: »Venetiis. Kal:X.Sept: 1711«. Die Herkunft des Textes ist noch ungeklärt. Er entspricht aber der verbreiteten italienischen Barocklyrik, die seelische Konflikte wie Liebeskummer zumeist metaphorisch in Naturbildern ausspricht. Diese Kantaten gaben offenbar den Ausschlag, dass der Kurprinz, nachdem er die Genehmigung hierfür bei seinem Vater Friedrich August I. aus Dresden eingeholt hatte, Heinichen als sächsischen Hofkapellmeister ab dem 1. August 1716 verpflichte. Zum Geburtstag des Kurprinzen am 17. Oktober 1716 komponierte Heinichen eine Serenata, welche die Musiker in Gondeln auf dem Canale grande aufführten.

Ingeniero Civil Químico / Producto de la crisis energética actual y el consumo proyectado al futuro, se están buscando maneras de diversificar la matriz de energía, abriéndose a diversas opciones de preferencia renovables. La gasificación de biomasa es una ellas y consiste en la oxidación parcial de las moléculas de carbono para obtener un gas con valor energético. La empresa ENERCOM, proveedora de equipos de combustión y secado, actualmente posee un gasificador del tipo downdraft con angostamiento. Sin embargo, algunas características del equipo lo hacen poco atractivo para la industria, principalmente, el régimen de operación batch, los despuntes de madera como materia prima y la seguridad. Por ello, se decide a considerar una operación en continuo y con pellets. El objetivo de este trabajo es diseñar un reactor continuo para gasificación de biomasa. Para ello, es necesario analizar desde el punto de vista técnico el reactor actual y determinar si es posible, bajo las condiciones requeridas, modificarlo para llevarlo a su aplicación industrial o se requiere de un diseño nuevo. Tras esa decisión, proponer los principales parámetros. Mediante un estudio del mercado de los gasificadores, se determina que el diseño downdraft es el que más se utiliza a nivel industrial y puede operar con pellets en continuo. Luego, con la ayuda de un modelo de balances de masa y energía, se logra predecir el funcionamiento del equipo en continuo, obteniendo de la composición del gas producto y el perfil de temperaturas. Se decide mantener el diseño downdraft con angostamiento. Esto implicará incluir un sistema de alimentación, para lo que se propone un tornillo sin fin alimentado desde una tolva. También, se requiere de un extractor de cenizas, para lo que se proponen dos ideas: i. tornillo sin fin, similar al de alimentación; o ii. tornillo de extracción húmeda (tornillo de Arquímedes), que retiraría ceniza suspendida en agua. Internamente, el diseño no necesita cambios importantes. No obstante, se requiere reducir la separación entre los rieles de la parrilla que sustenta la materia prima y agregar un vibrador que remueva las cenizas. Además, se propone agregar unos perfiles que ayuden a la caída del pellet y al paso de los gases a lo alto del equipo. Finalmente, se plantean lazos de control en la temperatura y presión para dar seguridad a la operación. Además, se propone un sistema de encendido automático. Todo esto permitirá operar remotamente el reactor, sin exponer a los operarios. Se cumple el objetivo principal de este trabajo. Se observa que cambiando el reactor actual a una operación continua con pellets, el uso efectivo de la energía de la madera aumenta de un 55% a un 73%. Esto se debe a un mejor aprovechamiento de la materia prima, que aumenta la producción de gas pobre de 1,9 [kg] por cada kilogramo de madera cargada a 2,2 [kg]. Se propone para futuros trabajos analizar la factibilidad económica del proyecto. También, sería bueno considerar de todas formas un nuevo diseño y sus respectivos estudios para la gasificación de pellets alimentados de forma continua.

The lecture was given on October 7, 1985. The discussion dealt with the stylistic characteristics of six oboe sonatas and preparation of a performing edition of the fifth sonata by the eighteenth-century oboist and composer Giuseppe Sammartini. After Sammartini emigrated from Milan to London in the 1720s, he became the leading oboist in England. Both his playing and his compositions were praised by contemporaneous writers including Burney and Hawkins. Sammartini's oboe sonatas share stylistic traits with the work of his baroque contemporaries while looking forward to the emergence of the classical style. Five of the sonatas show derivation from the sonata da camera, while one is a clear example of the sonata da chiesa. As some of the few baroque sonatas composed specifically for the oboe, they represent important new additions to a limited repertoire. The performance practice problems encountered included realization of the unfigured bass accompaniment, correcting errors in the manuscript, and providing performance directions for tempos, dynamics, articulation, and ornamentation. In addition to the lecture recital, three other recitals for solo oboe were given. The first recital was given on November 7, 1983 and included works by Antonio Vivaldi, Ernst Eichner, Bohuslav Martina, and Heinrich von Herzogenberg. The second recital was given on April 16, 1984 and included works by Johann Sebastian Bach, Georg Phillip Telemann, Ruth Crawford Seeger, and August Klughardt. The third recital was given on September 16, 1985 and included works by Paul Hindemith, Jean Franpaix, and Gary Smart. All four recitals were recorded on magnetic tape and are filed, along with the written version of the lecture materials, as a part of the dissertation.

El modelamiento de elementos estructurales se puede realizar actualmente en diferentes programas computacionales, las cuales se basan en conceptos y teorías de la mecánica estructural, las cuales se encuentran inmersas en su programación. Sin embargo, no siempre los conceptos en los programas comerciales cumplen con describir con mayor precisión el comportamiento de los elementos estructurales especialmente en el campo de la no linealidad. Por ello, se propone un modelo computacional del comportamiento no lineal geométrico de vigas, en base a un programa diseñado en MATLAB©, utilizando la formulación del Método de Elemento Finitos (FEM). Para la formulación del código del programa, se ha planteado el uso de la teoría de vigas de Timoshenko, considerándose esfuerzos cortantes en las vigas y una formulación Lagrangiana no lineal para deformaciones finitas. Se ha realizado la comparación entre el campo de desplazamientos propuesto por Timoshenko y la teoría clásica de vigas con la finalidad de poder comprobar la convergencia de teorías más robustas y explícitas en diferentes casos de vigas. El presente programa es capaz de calcular las deformaciones, esfuerzos y fuerzas internas de diferentes casos de vigas, los cuales han sido comparados con problemas benchmark de la bibliografía consultada para confirmar su convergencia. / The computational modeling of structural elements can be done in many different computational programs in the market today, that are based in concepts and theories of structural mechanics that are inside the code of the program. However, the concepts used in these programs do not always achieve an exact description of the structural behavior of structural elements, especially when it has no linear strain-displacement behavior. Therefore, this research describes a computational model of nonlinear strain-displacement relation of beams, based in a program designed in MATLAB©, using a finite element formulation. For the development of the code, it has presented the Timoshenko beam theory, where it has considerations shear deformations in beams, and a Lagrangian formulation for the strain-displacement relation for finite deformation. It has done comparison between the displacement of Timoshenko theory and the classic theory (Euler formulation), to verify the convergence of more robust and explicit theories in different cases of beams. This program is capable of calculate of displacements, stresses and internal forces of different beam problems, which has been compared with benchmark problems of the consulted bibliography for convergence check. / Tesis