A STUDY OF HEAT TRANSFER AND FLOW CHARACTERISTICS OF RISING TAYLOR BUBBLES

Practical application of flow boiling to ground- and space-based thermal management systems hinges on the ability to predict the system’s heat removal capabilities under expected operating conditions. Research in this field has shown that the heat transfer coefficient within two-phase heat exchangers can be largely dependent on the experienced flow regime. This finding has inspired an effort to develop mechanistic heat transfer models for each flow pattern which are likely to outperform traditional empirical correlations. As a contribution to the effort, this work aimed to identify the heat transfer mechanisms for the slug flow regime through analysis of individual Taylor bubbles. An experimental apparatus was developed to inject single vapor Taylor bubbles into co-currently flowing liquid HFE 7100. The heat transfer was measured as the bubble rose through a 6 mm inner diameter heated tube using an infrared thermography technique. High-speed flow visualization was obtained and the bubble film thickness measured in an adiabatic section. Experiments were conducted at various liquid mass fluxes (43-200 kg/m2s) and gravity levels (0.01g-1.8g) to characterize the effect of bubble drift velocity on the heat transfer mechanisms. Variable gravity testing was conducted during a NASA parabolic flight campaign. Results from the experiments showed that the drift velocity strongly affects the hydrodynamics and heat transfer of single elongated bubbles. At low gravity levels, bubbles exhibited shapes characteristic of capillary flows and the heat transfer enhancement due to the bubble was dominated by conduction through the thin film. At moderate to high gravity, traditional Taylor bubbles provided small values of enhancement within the film, but large peaks in the wake heat transfer occurred due to turbulent vortices induced by the film plunging into the trailing liquid slug. Characteristics of the wake heat transfer profiles were analyzed and related to the predicted velocity field. Results were compared and shown to agree with numerical simulations of colleagues from EPFL, Switzerland. In addition, a preliminary study was completed on the effect of a Taylor bubble passing through nucleate flow boiling, showing that the thinning thermal boundary layer within the film suppressed nucleation, thereby decreasing the heat transfer coefficient.

Benefits and Effects of Interactive Gaming Exercise as Compared to Traditional Exercise Techniques: An Investigation of the Relationship Between Physical Activity Levels and Mode of Activity in College Students

Gemstone Team F.I.T.N.E.S.S. (Fun Interactive Techniques for New Exercise and Sport Styles)

An analysis of the efficacy of low-scale concentrated photovoltaics

Gemstone Team LEAF (Light Energy Acquisition of the Future)

THE COMPLETE PRELUDES OF ALEXANDER SCRIABIN: THE EVOLUTION OF HIS REVOLUTIONARY COMPOSITIONAL STYLE

During the second half of the nineteenth century, a series of remarkable advances in musical composition emerged in the works of such innovative spirits as Franz Liszt, Hector Berlioz and Richard Wagner. Their pioneering works exerted an extraordinary impact on the music of the subsequent generation of composers--of disparate nationalities-who were active at the dawn of the 20th century: Including most notably Claude-Achille Debussy, Gustav Mahler, Richard Strauss, and Alexander Nikolayevich Scriabin. These important musical figures, each one leaving an indelible and formative imprint on late-nineteenth century Romantic style, together launched the modern era in music. Scriabin stands alone as a transcendental visionary: His music, initiated in the fashion of Chopin and Liszt, wanders through the realms of Debussy and Wagner, and, ultimately abandoning late Romantic tradition, unlocks the heretofore unforeseen power of atonality, bitonality, polyrhythms and key-signature free compositions. Arguably, Scriabin's compositions count among the most innovative, idiosyncratic and bewitching of all time. The development of Scriabin's groundbreaking compositional style is best understood by means of his piano works, which comprise the majority of his oeuvre. Beyond the larger works-his twelve sonatas, a concerto and a fantasy-Scriabin's piano explorations are also represented by miniature gems: The mazurkas, impromptus, waltzes, poems, a polonaise, etudes, nocturnes, morceaux and, in particular, the preludes. Scriabin's 90 preludes for piano, arranged in several opus numbers, richly exemplify the striking evolution of his ingenious music, his idiosyncratic philosophy and his provocative personality.

SAXOPHONE SONATAS 1980-2010

The purpose of this dissertation project identifies contemporary solo saxophone literature, specifically sonatas between the years 1980 and 2010. The overwhelming majority of repertoire written during these thirty years consisted primarily of either multi-movement or through-composed character pieces. By limiting the selected repertoire to sonatas one can still investigate the breadth of the literature that has helped validate the saxophone in the realm of classical music in a format that has seemingly fallen out of favor with composers. The saxophone had developed a unique voice by the middle of the twentieth century in both Europe and in the United States. European composers such as Claude Debussy, Florent Schmidt, Jacques Ibert, Darius Milhaud, Alexander Glazounov, Erwin Schulhoff and Bernard Heiden recognized the potential and beauty of the instrument, while the saxophone had found quite a different niche in vaudeville, jazz, and military bands in the United States. If not for the dynamic performances by concert saxophonist such as Marcel Mule, Sigurd Rascher, Jean-Marie Londeix, Daniel Deffayet, Cecil Lesson, Larry Teal, Eugene Rousseau, Fredrick Hemke and Donald Sinta, the timbral possibilities and technical virtuosity of the saxophone would not have been discovered. The awe inspiring performances by these soloists led to the commissioning of a multitude of works by composers looking to expand the sonic possibilities of this relatively new instrument. Through the 1970's American composers such as Leslie Bassett, Paul Creston, Henry Brant, Robert Muczynski, and Karel Husa were writing significant works for the saxophone, while European composers such as IngolfDahl, Edison Denisov, Alfred Desenclos, Henri Tomasi and Marius Constant were each making their own contributions, all leading to a significant quantity of repertoire that met the quality demands set by the performers. The compositions chosen for this dissertation project were selected after numerous performance, pragmatic, programming and pedagogical considerations were taken into account. The three recitals occurred on: March 7, 2010, December 10, 2010 and May 1, 2011 in either the Gildenhorn Recital Hall or Lecture Hall 2100.