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Description
The heat transfer enhancements available from expanding the cross-section of a boiling microchannel are explored analytically and experimentally. Evaluation of the literature on critical heat flux in flow boiling and associated pressure drop behavior is presented with predictive critical heat flux (CHF) and pressure drop correlations. An optimum channel configuration

The heat transfer enhancements available from expanding the cross-section of a boiling microchannel are explored analytically and experimentally. Evaluation of the literature on critical heat flux in flow boiling and associated pressure drop behavior is presented with predictive critical heat flux (CHF) and pressure drop correlations. An optimum channel configuration allowing maximum CHF while reducing pressure drop is sought. A perturbation of the channel diameter is employed to examine CHF and pressure drop relationships from the literature with the aim of identifying those adequately general and suitable for use in a scenario with an expanding channel. Several CHF criteria are identified which predict an optimizable channel expansion, though many do not. Pressure drop relationships admit improvement with expansion, and no optimum presents itself. The relevant physical phenomena surrounding flow boiling pressure drop are considered, and a balance of dimensionless numbers is presented that may be of qualitative use. The design, fabrication, inspection, and experimental evaluation of four copper microchannel arrays of different channel expansion rates with R-134a refrigerant is presented. Optimum rates of expansion which maximize the critical heat flux are considered at multiple flow rates, and experimental results are presented demonstrating optima. The effect of expansion on the boiling number is considered, and experiments demonstrate that expansion produces a notable increase in the boiling number in the region explored, though no optima are observed. Significant decrease in the pressure drop across the evaporator is observed with the expanding channels, and no optima appear. Discussion of the significance of this finding is presented, along with possible avenues for future work.
ContributorsMiner, Mark (Author) / Phelan, Patrick E (Thesis advisor) / Baer, Steven (Committee member) / Chamberlin, Ralph (Committee member) / Chen, Kangping (Committee member) / Herrmann, Marcus (Committee member) / Arizona State University (Publisher)
Created2013
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Description
In order to cope with the decreasing availability of symphony jobs and collegiate faculty positions, many musicians are starting to pursue less traditional career paths. Also, to combat declining audiences, musicians are exploring ways to cultivate new and enthusiastic listeners through relevant and engaging performances. Due to these challenges, many

In order to cope with the decreasing availability of symphony jobs and collegiate faculty positions, many musicians are starting to pursue less traditional career paths. Also, to combat declining audiences, musicians are exploring ways to cultivate new and enthusiastic listeners through relevant and engaging performances. Due to these challenges, many community-based chamber music ensembles have been formed throughout the United States. These groups not only focus on performing classical music, but serve the needs of their communities as well. The problem, however, is that many musicians have not learned the business skills necessary to create these career opportunities. In this document I discuss the steps ensembles must take to develop sustainable careers. I first analyze how groups build a strong foundation through getting to know their communities and creating core values. I then discuss branding and marketing so ensembles can develop a public image and learn how to publicize themselves. This is followed by an investigation of how ensembles make and organize their money. I then examine the ways groups ensure long-lasting relationships with their communities and within the ensemble. I end by presenting three case studies of professional ensembles to show how groups create and maintain successful careers. Ensembles must develop entrepreneurship skills in addition to cultivating their artistry. These business concepts are crucial to the longevity of chamber groups. Through interviews of successful ensemble members and my own personal experiences in the Tetra String Quartet, I provide a guide for musicians to use when creating a community-based ensemble.
ContributorsDalbey, Jenna (Author) / Landschoot, Thomas (Thesis advisor) / McLin, Katherine (Committee member) / Ryan, Russell (Committee member) / Solis, Theodore (Committee member) / Spring, Robert (Committee member) / Arizona State University (Publisher)
Created2013
ContributorsChang, Ruihong (Performer) / ASU Library. Music Library (Publisher)
Created2018-03-29
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Description
American Primitive is a composition written for wind ensemble with an instrumentation of flute, oboe, clarinet, bass clarinet, alto, tenor, and baritone saxophones, trumpet, horn, trombone, euphonium, tuba, piano, and percussion. The piece is approximately twelve minutes in duration and was written September - December 2013. American Primitive is absolute

American Primitive is a composition written for wind ensemble with an instrumentation of flute, oboe, clarinet, bass clarinet, alto, tenor, and baritone saxophones, trumpet, horn, trombone, euphonium, tuba, piano, and percussion. The piece is approximately twelve minutes in duration and was written September - December 2013. American Primitive is absolute music (i.e. it does not follow a specific narrative) comprising blocks of distinct, contrasting gestures which bookend a central region of delicate textural layering and minimal gestural contrast. Though three gestures (a descending interval followed by a smaller ascending interval, a dynamic swell, and a chordal "chop") were consciously employed throughout, it is the first gesture of the three that creates a sense of unification and overall coherence to the work. Additionally, the work challenges listeners' expectations of traditional wind ensemble music by featuring the trumpet as a quasi-soloist whose material is predominately inspired by transcriptions of jazz solos. This jazz-inspired material is at times mimicked and further developed by the ensemble, also often in a soloistic manner while the trumpet maintains its role throughout. This interplay of dialogue between the "soloists" and the "ensemble" further skews listeners' conceptions of traditional wind ensemble music by featuring almost every instrument in the ensemble. Though the term "American Primitive" is usually associated with the "naïve art" movement, it bears no association to the music presented in this work. Instead, the term refers to the author's own compositional attitudes, education, and aesthetic interests.
ContributorsJandreau, Joshua (Composer) / Rockmaker, Jody D (Thesis advisor) / Rogers, Rodney I (Committee member) / Demars, James R (Committee member) / Arizona State University (Publisher)
Created2014
Description
The flow of liquid PDMS (10:1 v/v base to cross-linker ratio) in open, rectangular silicon micro channels, with and without a hexa-methyl-di-silazane (HMDS) or poly-tetra-fluoro-ethylene (PTFE) (120 nm) coat, was studied. Photolithographic patterning and etching of silicon wafers was used to create micro channels with a range of widths (5-50

The flow of liquid PDMS (10:1 v/v base to cross-linker ratio) in open, rectangular silicon micro channels, with and without a hexa-methyl-di-silazane (HMDS) or poly-tetra-fluoro-ethylene (PTFE) (120 nm) coat, was studied. Photolithographic patterning and etching of silicon wafers was used to create micro channels with a range of widths (5-50 μm) and depths (5-20 μm). The experimental PDMS flow rates were compared to an analytical model based on the work of Lucas and Washburn. The experimental flow rates closely matched the predicted flow rates for channels with an aspect ratio (width to depth), p, between one and two. Flow rates in channels with p less than one were higher than predicted whereas the opposite was true for channels with p greater than two. The divergence between the experimental and predicted flow rates steadily increased with increasing p. These findings are rationalized in terms of the effect of channel dimensions on the front and top meniscus morphology and the possible deviation from the no-slip condition at the channel walls at high shear rates.

In addition, a preliminary experimental setup for calibration tests on ultrasensitive PDMS cantilever beams is reported. One loading and unloading cycle is completed on a microcantilever PDMS beam (theoretical stiffness 0.5 pN/ µm). Beam deflections are actuated by adjusting the buoyancy force on the beam, which is submerged in water, by the addition of heat. The expected loading and unloading curve is produced, albeit with significant noise. The experimental results indicate that the beam stiffness is a factor of six larger than predicted theoretically. One probable explanation is that the beam geometry may change when it is removed from the channel after curing, making assumptions about the beam geometry used in the theoretical analysis inaccurate. This theory is bolstered by experimental data discussed in the report. Other sources of error which could partially contribute to the divergent results are discussed. Improvements to the experimental setup for future work are suggested.
ContributorsSowers, Timothy Wayne (Author) / Rajagopalan, Jagannathan (Thesis advisor) / Herrmann, Marcus (Committee member) / Huang, Huei-Ping (Committee member) / Arizona State University (Publisher)
Created2014
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Description
This project is a practical annotated bibliography of original works for oboe trio with the specific instrumentation of two oboes and English horn. Presenting descriptions of 116 readily available oboe trios, this project is intended to promote awareness, accessibility, and performance of compositions within this genre.

The annotated bibliography focuses

This project is a practical annotated bibliography of original works for oboe trio with the specific instrumentation of two oboes and English horn. Presenting descriptions of 116 readily available oboe trios, this project is intended to promote awareness, accessibility, and performance of compositions within this genre.

The annotated bibliography focuses exclusively on original, published works for two oboes and English horn. Unpublished works, arrangements, works that are out of print and not available through interlibrary loan, or works that feature slightly altered instrumentation are not included.

Entries in this annotated bibliography are listed alphabetically by the last name of the composer. Each entry includes the dates of the composer and a brief biography, followed by the title of the work, composition date, commission, and dedication of the piece. Also included are the names of publishers, the length of the entire piece in minutes and seconds, and an incipit of the first one to eight measures for each movement of the work.

In addition to providing a comprehensive and detailed bibliography of oboe trios, this document traces the history of the oboe trio and includes biographical sketches of each composer cited, allowing readers to place the genre of oboe trios and each individual composition into its historical context. Four appendices at the end include a list of trios arranged alphabetically by composer's last name, chronologically by the date of composition, and by country of origin and a list of publications of Ludwig van Beethoven's oboe trios from the 1940s and earlier.
ContributorsSassaman, Melissa Ann (Author) / Schuring, Martin (Thesis advisor) / Buck, Elizabeth (Committee member) / Holbrook, Amy (Committee member) / Hill, Gary (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Recent literature indicates potential benefits in microchannel cooling if an inlet orifice is used to suppress pressure oscillations that develop under two-phase conditions. This study investigates the costs and benefits of using an adjustable microchannel inlet orifice. The focus is on orifice effect during steady-state boiling and critical heat flux

Recent literature indicates potential benefits in microchannel cooling if an inlet orifice is used to suppress pressure oscillations that develop under two-phase conditions. This study investigates the costs and benefits of using an adjustable microchannel inlet orifice. The focus is on orifice effect during steady-state boiling and critical heat flux (CHF) in the channels using R134a in a pumped refrigerant loop (PRL). To change orifice size, a dam controlled with a micrometer was placed in front of 31 parallel microchannels. Each channel had a hydraulic diameter of 0.235 mm and a length of 1.33 cm. For steady state two-phase conditions, mass fluxes of 300 kg m-2 s-1 and 600 kg m-2 s-1were investigated. For orifice sizes with a hydraulic diameter to unrestricted hydraulic diameter (Dh:Dh,ur) ratio less than 35 percent, oscillations were reduced and wall temperatures fell up to 1.5 °C. Critical heat flux data were obtained for 7 orifice sizes with mass fluxes from 186 kg m-2 s-1 to 847 kg m-2 s-1. For all mass fluxes and inlet conditions tested, CHF values for a Dh:Dh,ur ratio of 1.8 percent became increasingly lower (up to 37 W cm-2 less) than those obtained with larger orifices. An optimum orifice size with Dh:Dh,ur of 35 percent emerged, offering up to 5 W cm-2 increase in CHF over unrestricted conditions at the highest mass flux tested, 847 kg m-2 s-1. These improvements in cooling ability with inlet orifices in place under both steady-state and impending CHF conditions are modest, leading to the conclusion that inlet orifices are only mildly effective at improving heat transfer coefficients. Stability of the PRL used for experimentation was also studied and improved. A vapor compression cycle's (VCC) proportional, integral, and derivative controller was found to adversely affect stability within the PRL and cause premature CHF. Replacing the VCC with an ice water heat sink maintained steady pumped loop system pressures and mass flow rates. The ice water heat sink was shown to have energy cost savings over the use of a directly coupled VCC for removing heat from the PRL.
ContributorsOdom, Brent A (Author) / Phelan, Patrick E (Thesis advisor) / Herrmann, Marcus (Committee member) / Trimble, Steve (Committee member) / Tasooji, Amaneh (Committee member) / Holcomb, Don (Committee member) / Arizona State University (Publisher)
Created2012
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Description
Microchannel heat sinks can possess heat transfer characteristics unavailable in conventional heat exchangers; such sinks offer compact solutions to otherwise intractable thermal management problems, notably in small-scale electronics cooling. Flow boiling in microchannels allows a very high heat transfer rate, but is bounded by the critical heat flux (CHF). This

Microchannel heat sinks can possess heat transfer characteristics unavailable in conventional heat exchangers; such sinks offer compact solutions to otherwise intractable thermal management problems, notably in small-scale electronics cooling. Flow boiling in microchannels allows a very high heat transfer rate, but is bounded by the critical heat flux (CHF). This thesis presents a theoretical-numerical study of a method to improve the heat rejection capability of a microchannel heat sink via expansion of the channel cross-section along the flow direction. The thermodynamic quality of the refrigerant increases during flow boiling, decreasing the density of the bulk coolant as it flows. This may effect pressure fluctuations in the channels, leading to nonuniform heat transfer and local dryout in regions exceeding CHF. This undesirable phenomenon is counteracted by permitting the cross-section of the microchannel to increase along the direction of flow, allowing more volume for the vapor. Governing equations are derived from a control-volume analysis of a single heated rectangular microchannel; the cross-section is allowed to expand in width and height. The resulting differential equations are solved numerically for a variety of channel expansion profiles and numbers of channels. The refrigerant is R-134a and channel parameters are based on a physical test bed in a related experiment. Significant improvement in CHF is possible with moderate area expansion. Minimal additional manufacturing costs could yield major gains in the utility of microchannel heat sinks. An optimum expansion rate occurred in certain cases, and alterations in the channel width are, in general, more effective at improving CHF than alterations in the channel height. Modest expansion in height enables small width expansions to be very effective.
ContributorsMiner, Mark (Author) / Phelan, Patrick E (Thesis advisor) / Herrmann, Marcus (Committee member) / Chen, Kangping (Committee member) / Arizona State University (Publisher)
Created2011
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Description
Four Souvenirs for Violin and Piano was composed by Paul Schoenfeld (b.1947) in 1990 as a showpiece, spotlighting the virtuosity of both the violin and piano in equal measure. Each movement is a modern interpretation of a folk or popular genre, re- envisioned over intricate jazz harmonies and rhythms. The

Four Souvenirs for Violin and Piano was composed by Paul Schoenfeld (b.1947) in 1990 as a showpiece, spotlighting the virtuosity of both the violin and piano in equal measure. Each movement is a modern interpretation of a folk or popular genre, re- envisioned over intricate jazz harmonies and rhythms. The work was commissioned by violinist Lev Polyakin, who specifically requested some short pieces that could be performed in a local jazz establishment named Night Town in Cleveland, Ohio. The result is a work that is approximately fifteen minutes in length. Schoenfeld is a respected composer in the contemporary classical music community, whose Café Music (1986) for piano trio has recently become a staple of the standard chamber music repertoire. Many of his other works, however, remain in relative obscurity. It is the focus of this document to shed light on at least one other notable composition; Four Souvenirs for Violin and Piano. Among the topics to be discussed regarding this piece are a brief history behind the genesis of this composition, a structural summary of the entire work and each of its movements, and an appended practice guide based on interview and coaching sessions with the composer himself. With this project, I hope to provide a better understanding and appreciation of this work.
ContributorsJanczyk, Kristie Annette (Author) / Ryan, Russell (Thesis advisor) / Campbell, Andrew (Committee member) / Norton, Kay (Committee member) / Arizona State University (Publisher)
Created2015
ContributorsPagano, Caio, 1940- (Performer) / Mechetti, Fabio (Conductor) / Buck, Elizabeth (Performer) / Schuring, Martin (Performer) / Spring, Robert (Performer) / Rodrigues, Christiano (Performer) / Landschoot, Thomas (Performer) / Rotaru, Catalin (Performer) / Avanti Festival Orchestra (Performer) / ASU Library. Music Library (Publisher)
Created2018-03-02