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Title: MAGNETIC PROPERTIES OF SPUTTER DEPOSITED FE-BASED AMORPHOUS THIN FILMS FOR RESONATOR APPLICATION.
Creator: China, Chaitali, Coffey, Kevin, University of Central Florida
Abstract / Description: In this study we investigate the magnetic properties of Fe-based amorphous thin films. Fe1-x-y-zBxSiyCz, Fe80-xNixB20, Fe80-xMnxB20, and Fe73-xMnxB27 films were deposited on silicon and glass substrates in a DC and RF magnetron sputtering system. Inductive magnetic measurements were performed to investigate the magnetic properties, including induced anisotropy and magnetostriction, of the as-deposited and annealed films using an M-H Looper. The chemical composition of the films was...
Show moreIn this study we investigate the magnetic properties of Fe-based amorphous thin films. Fe1-x-y-zBxSiyCz, Fe80-xNixB20, Fe80-xMnxB20, and Fe73-xMnxB27 films were deposited on silicon and glass substrates in a DC and RF magnetron sputtering system. Inductive magnetic measurements were performed to investigate the magnetic properties, including induced anisotropy and magnetostriction, of the as-deposited and annealed films using an M-H Looper. The chemical composition of the films was characterized using secondary ion mass spectroscopy (SIMS). The physical thickness of the films was determined by use of a stylus profilometer. The M-H Looper studies indicated that the induced anisotropy (Hk) depends strongly on the nickel concentration as well as on the annealing conditions, specifically the time and temperature of the annealing process. For the same metalloid concentration, the induced anisotropy has a maximum as a function of Ni. For the same nickel concentration and annealing time, it was found that the value of Hk decreases with the increase in annealing temperature. For each composition studied, low temperature long time annealing showed a higher value of Hk compared to high temperature short time annealing. From the magnetostriction values of Fe80-xNixB20 alloys, it was found that the sputter deposited films show similar trend but differ in magnitude when compared with ribbon samples. The magnetostriction of annealed thin films is found to be representative of ribbon samples. A potential composition modification to improve the strength of the field induced anisotropy is the addition of low levels of Mn.
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Date Issued: 2006
Identifier: CFE0001275, ucf:46896
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001275

Title: CHARACTERIZATION OF MICROSTRUCTURAL AND CHEMICAL FEATURES IN CU-IN-GA-SE-S-BASED THIN-FILM SOLAR CELLS.
Creator: Halbe, Ankush, Heinrich, Helge, University of Central Florida
Abstract / Description: Thin-film solar cells are potentially low-cost devices to convert sunlight into electricity. Improvements in the conversion efficiencies of these cells reduce material utilization cost and make it commercially viable. Solar cells from the Thin-Film Physics Group, ETH Zurich, Switzerland and the Florida Solar Energy Center (FSEC), UCF were characterized for defects and other microstructural features within the thin-film structure and at the interfaces using transmission electron microscopy ...
Show moreThin-film solar cells are potentially low-cost devices to convert sunlight into electricity. Improvements in the conversion efficiencies of these cells reduce material utilization cost and make it commercially viable. Solar cells from the Thin-Film Physics Group, ETH Zurich, Switzerland and the Florida Solar Energy Center (FSEC), UCF were characterized for defects and other microstructural features within the thin-film structure and at the interfaces using transmission electron microscopy (TEM). The present thesis aims to provide a feedback to these groups on their deposition processes to understand the correlations between processing, resulting microstructures, and the conversion efficiencies of these devices. Also, an optical equipment measuring photocurrents from a solar cell was developed for the identification of defect-prone regions of a thin-film solar cell. The focused ion beam (FIB) technique was used to prepare TEM samples. Bright-field TEM along with scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDS) including elemental distribution line scans and maps were extensively used for characterizing the absorber layer and interfaces both above and below the absorber layer. Energy-filtered transmission electron microscopy (EFTEM) was applied in cases where EDS results were inconclusive due to the overlap of X-ray energies of certain elements, especially molybdenum and sulfur. Samples from ETH Zurich were characterized for changes in the CIGS (Cu(In,Ga)Se2) microstructure due to sodium incorporation from soda-lime glass or from a post-deposition treatment with NaF as a function of CIGS deposition temperature. The CIGS-CdS interface becomes smoother and the small columnar CIGS grains close to the Mo back contact disappear with increasing CIGS deposition temperature. At 773 K the two sodium incorporation routes result in large differences in the microstructures with a significantly larger grain size for the samples after post-deposition Na incorporation. Porosity was observed in the absorber layer close to the back contact in the samples from FSEC. The reason for porosity could be materials evaporation in the gallium beam of the FIB or a processing effect. The porosity certainly indicates heterogeneities of the composition of the absorber layer near the back contact. A Mo-Se rich layer (possibly MoSe2) was formed at the interface between CIGS/CIGSS and Mo improving the quality of the junction. Other chemical heterogeneities include un-sulfurized Cu-Ga deposits, residual Se from the selenization/ sulfurization chamber in CIGS2 and the formation of Cu-rich regions which are attributed to decomposition effects in the Ga beam of the FIB. Wavy absorber surfaces were observed for some of the cells with occasional discontinuities in the metal grids. The 50 nm thick CdS layer, however, remained continuous in all the samples under investigation. For a sample with a transparent back contact, a 10 nm Mo layer was deposited on ITO (indium tin oxide) before deposition of the CIGS2 (Cu(In,Ga)S2) layer. EFTEM maps indicate that a MoS2 layer does not form for such a Mo/MoS2-ITO back contact. Instead, absorber layer material diffuses through the thin Mo layer onto the ITO forming two layers of CIGS2 on either side of Mo with different compositions. Furthermore, an optical beam induced current (OBIC) system with micron level resolution was successfully developed and preliminary photocurrent maps were acquired to microscopically identify regions within a thin-film solar cell with undesirable microstructural features. Such a system, when fully operational, will provide the means for the identification of special regions from where samples for TEM analysis can be obtained using the FIB technique to study specifically the defects responsible for local variations in solar cell properties.
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Date Issued: 2006
Identifier: CFE0001022, ucf:46807
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001022

Title: CONJUGATE HEAT TRANSFER ANALYSIS OF COMBINED REGENERATIVE AND DISCRETE FILM COOLING IN A ROCKET NOZZLE.
Creator: Pearce, Charlotte M, Kapat, Jayanta, University of Central Florida
Abstract / Description: Conjugate heat transfer analysis has been carried out on an 89kN thrust chamber in order to evaluate whether combined discrete film cooling and regenerative cooling in a rocket nozzle is feasible. Several cooling configurations were tested against a baseline design of regenerative cooling only. New designs include combined cooling channels with one row of discrete film cooling holes near the throat of the nozzle, and turbulated cooling channels combined with a row of discrete film cooling...
Show moreConjugate heat transfer analysis has been carried out on an 89kN thrust chamber in order to evaluate whether combined discrete film cooling and regenerative cooling in a rocket nozzle is feasible. Several cooling configurations were tested against a baseline design of regenerative cooling only. New designs include combined cooling channels with one row of discrete film cooling holes near the throat of the nozzle, and turbulated cooling channels combined with a row of discrete film cooling holes. Blowing ratio and channel mass flow rate were both varied for each design. The effectiveness of each configuration was measured via the maximum hot gas-side nozzle wall temperature, which can be correlated to number of cycles to failure. A target maximum temperature of 613K was chosen. Combined film and regenerative cooling, when compared to the baseline regenerative cooling, reduced the hot gas side wall temperature from 667K to 638K. After adding turbulators to the cooling channels, combined film and regenerative cooling reduced the temperature to 592K. Analysis shows that combined regenerative and film cooling is feasible with significant consequences, however further improvements are possible with the use of turbulators in the regenerative cooling channels.
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Date Issued: 2016
Identifier: CFH2000138, ucf:45923
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH2000138

Title: THE SEARCH FOR TRUTH IN THE DIGITAL CINEMATIC SPACE AND GREEN SCREEN PERFORMANCES.
Creator: Dalton, Kade, Shults, Kate, University of Central Florida
Abstract / Description: With the advent of the blockbuster and its visual effects, film has grown to accept these effects and the technology behind them, namely green screen mattes, as cornerstones to the post-production process. The propensity of green screen in all types of productions, especially those involving actors and their performances, raises questions about the methodology and workflow behind its common practice. Using real-life environments and people to create narrative scenes, this project explores the...
Show moreWith the advent of the blockbuster and its visual effects, film has grown to accept these effects and the technology behind them, namely green screen mattes, as cornerstones to the post-production process. The propensity of green screen in all types of productions, especially those involving actors and their performances, raises questions about the methodology and workflow behind its common practice. Using real-life environments and people to create narrative scenes, this project explores the utilization of matte backgrounds to inform the rehearsal and performance aspects of cinematic story-telling.
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Date Issued: 2014
Identifier: CFH0004714, ucf:45409
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004714

Title: PERCEPTION OF MENTAL ILLNESS BASED UPON ITS PORTRAYAL IN FILM.
Creator: Hanley, Erika, Donley, Amy, University of Central Florida
Abstract / Description: Perceptions can be influenced by the media concerning different groups of people. As a result of the importance of the media in how individuals obtain information and formulate opinions, how different groups are presented whether negatively or positively is important. This research examines the portrayal of mental illness in films and the impact that such portrayals have on the perceptions of mental illness of the viewers. Mental illness representations can be found quite prevalently among...
Show morePerceptions can be influenced by the media concerning different groups of people. As a result of the importance of the media in how individuals obtain information and formulate opinions, how different groups are presented whether negatively or positively is important. This research examines the portrayal of mental illness in films and the impact that such portrayals have on the perceptions of mental illness of the viewers. Mental illness representations can be found quite prevalently among film and the way in which it is represented can be important as to how populations perceive those with mental disorders. This thesis looks to explore perceptions of mental illness and beliefs from those who have viewed films that portray characters with mental disorders. Through the use of an online survey, one hundred and ninety five participants provided data for this study. Based on previous research, it was hypothesized that individuals who had seen more films portraying mental illness would have more knowledge and sympathy regarding mental illness compared those who had seen less films portraying mental illness. It was also hypothesized that social stereotypes surrounding mental disorders would be present in the knowledge that individuals had more so than factual data about mental disorders. Women were predicted to express more sympathy than men. A statistical analysis program was used to analyze the resulting data including the use of correlations and t-tests. Evidence indicated that the amount of films viewed portraying mental illness did not have an impact on knowledge or sympathy regarding mental illness. Perceptions of mental illness are still a relevant topic and the awareness of facts surrounding mental disorders should continue to be spread.
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Date Issued: 2015
Identifier: CFH0004848, ucf:45441
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004848

Title: AN EXPERIMENTAL AND NUMERICAL STUDY OF SECONDARY FLOWS AND FILM COOLING EFFECTIVENESS IN A TRANSONIC CASCADE.
Creator: Kullberg, James, Kapat, Jayanta, University of Central Florida
Abstract / Description: In the modern world, gas turbines are widely used in aircraft propulsion and electricity generation. These applications represent a massive use of energy worldwide, so even a very small increase in efficiency would have a significant beneficial economic and environmental impact. There are many ways to optimize the operation of a gas turbine, but a fundamental approach is to increase the turbine inlet temperature to increase the basic thermodynamic efficiency of the turbine. However, these...
Show moreIn the modern world, gas turbines are widely used in aircraft propulsion and electricity generation. These applications represent a massive use of energy worldwide, so even a very small increase in efficiency would have a significant beneficial economic and environmental impact. There are many ways to optimize the operation of a gas turbine, but a fundamental approach is to increase the turbine inlet temperature to increase the basic thermodynamic efficiency of the turbine. However, these temperatures are already well above the melting temperature of the components. A primary cooling methodology, called film cooling, creates a blanket of cool air over the surface and is an effective way to help protect these components from the hot mainstream gasses. This paper focuses on the effect of the film holes upstream of the first row of blades in the turbine because this is the section that experiences the highest thermal stresses. Many factors can determine the effectiveness of the film cooling, so a complete understanding can lead to effective results with the minimum flow rate of coolant air. Many studies have been published on the subject of film cooling, but because of the difficulty and expense of simulating turbine realistic conditions, many authors introduce vast simplifications such as low speed conditions or linear cascades. These simplifications do not adequately represent the behavior of a turbine and therefore their results are of limited use. This study attempts to eliminate many of those simplifications. The test rig used in this research is based on the NASA-GE E3 design, which stands for Energy Efficient Engine. It was introduced into the public domain to provide an advanced platform from which open-literature research could be performed. Experimental tests on a transonic annular rig are time-consuming and expensive, so it is desirable to use experimental results to validate a computational model which can then be used to extract much more information. The purpose of this work is to create a numerical model that can be used to simulate many different scenarios and then to apply these results to experimental data.
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Date Issued: 2011
Identifier: CFH0003772, ucf:44728
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0003772

Title: CLASSICAL SIZE EFFECT IN CU THIN FILMS: IMPACT OF SURFACE AND GRAIN BOUNDARY SCATTERING ON RESISTIVITY.
Creator: Sun, Tik, Coffey, Kevin, University of Central Florida
Abstract / Description: Surface and grain boundary electron scattering contribute significantly to resistivity as the dimensions of polycrystalline metallic conductors are reduced to, and below, the electron mean free path. A quantitative measurement of the relative contributions of surface and grain boundary scattering to resistivity is very challenging, requiring not only the preparation of suitably small conductors having independent variation of the two relevant length scales, namely, the sample critical...
Show moreSurface and grain boundary electron scattering contribute significantly to resistivity as the dimensions of polycrystalline metallic conductors are reduced to, and below, the electron mean free path. A quantitative measurement of the relative contributions of surface and grain boundary scattering to resistivity is very challenging, requiring not only the preparation of suitably small conductors having independent variation of the two relevant length scales, namely, the sample critical dimension and the grain size, but also independent experimental quantification of these two length scales. In most work to date the sample grain size has been either assumed equal to conductor dimension or measured for only a small number of grains. Thus, the quantification of the classical size effect still suffers from an uncertainty in the relative contributions of surface and grain boundary scattering. In this work, a quantitative analysis of both surface and grain boundary scattering in Cu thin films with independent variation of film thickness (27 nm to 158 nm) and grain size (35 nm to 425 nm) in samples prepared by sub-ambient temperature film deposition followed by annealing is reported. Film resistivities of carefully characterized samples were measured at both room temperature and at 4.2 K and were compared with several scattering models that include the effects of surface and grain boundary scattering. Grain boundary scattering is found to provide the strongest contribution to the resistivity increase. However, a weaker, but significant, role is also observed for surface scattering. Several of the published models for grain boundary and surface scattering are explored and the Matthiessen's rule combination of the Mayadas and Shatzkes' model of grain boundary scattering and Fuchs and Sondheimer's model of surface scattering resistivity contributions is found to be most appropriate. It is found that the experimental data are best described by a grain boundary reflection coefficient of 0.43 and a surface specularity coefficient of 0.52. This analysis finds a significantly lower contribution from surface scattering than has been reported in previous works, which is in part due to the careful quantitative microstructural characterization of samples performed. The data does suggest that there is a roughness dependence to the surface scattering, but this was not conclusively demonstrated. Voids and impurities were found to have negligible impact on the measured resistivities of the carefully prepared films.
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Date Issued: 2009
Identifier: CFE0002959, ucf:47949
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002959

Title: Golden Years.
Creator: Malik, Sienna, Bartkevicius, Jocelyn, Stanfill, Mel, Thaxton, Terry, University of Central Florida
Abstract / Description: Golden Years is the culmination of the author's studies in Creative Nonfiction writing, with attention to hybrid forms of the genre, combined with her professional background in screenwriting, and research interests in nostalgia and cultural preservation in the modern age. In the collection of essays, the author blends established forms of Creative Nonfiction, such as the braided essay, with literary conventions borrowed from other forms of written communication, such as the screenplay (("...
Show moreGolden Years is the culmination of the author's studies in Creative Nonfiction writing, with attention to hybrid forms of the genre, combined with her professional background in screenwriting, and research interests in nostalgia and cultural preservation in the modern age. In the collection of essays, the author blends established forms of Creative Nonfiction, such as the braided essay, with literary conventions borrowed from other forms of written communication, such as the screenplay ((")You Must Remember This,(") (")Driver's Seat(")), the cookbook ((")Tip of my Tongue(")), a travel guide ((")A Trolley Runs Through It(")) and fabulist fiction ((")Selkie on the Shore(")). Through these hybrid forms, Golden Years explores the narrator's fascinations with music, cinema, and fashions of the past, with crafting the perfect pot of vegetarian chili, and with marine mammals. Through the blending of personal essay with cultural criticism, the author explores how these loves have shaped her relationship with the world around her.
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Date Issued: 2018
Identifier: CFE0007344, ucf:52128
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007344

Title: INVERSE BOUNDARY ELEMENT/GENETIC ALGORITHM METHOD FOR RECONSTRUCTION OF MULTI-DIMENSIONAL HEAT FLUX DISTRIBUTIONS WITH FILM COOLING APPLICATIONS.
Creator: Silieti, Mahmood, Kassab, Alain, University of Central Florida
Abstract / Description: A methodology is formulated for the solution of the inverse problem concerned with the reconstruction of multi-dimensional heat fluxes for film cooling applications. The motivation for this study is the characterization of complex thermal conditions in industrial applications such as those encountered in film cooled turbomachinery components. The heat conduction problem in the metal endwall/shroud is solved using the boundary element method (bem), and the inverse problem is solved using a...
Show moreA methodology is formulated for the solution of the inverse problem concerned with the reconstruction of multi-dimensional heat fluxes for film cooling applications. The motivation for this study is the characterization of complex thermal conditions in industrial applications such as those encountered in film cooled turbomachinery components. The heat conduction problem in the metal endwall/shroud is solved using the boundary element method (bem), and the inverse problem is solved using a genetic algorithm (ga). Thermal conditions are overspecified at exposed surfaces amenable to measurement, while the temperature and surface heat flux distributions are unknown at the film cooling hole/slot walls. The latter are determined in an iterative process by developing two approaches. The first approach, developed for 2d applications, solves an inverse problem whose objective is to adjust the film cooling hole/slot wall temperatures and heat fluxes until the temperature and heat flux at the measurement surfaces are matched in an overall heat conduction solution. The second approach, developed for 2d and 3d applications, is to distribute a set of singularities (sinks) at the vicinity of the cooling slots/holes surface inside a fictitious extension of the physical domain or along cooling hole centerline with a given initial strength distribution. The inverse problem iteratively alters the strength distribution of the singularities (sinks) until the measuring surfaces heat fluxes are matched. The heat flux distributions are determined in a post-processing stage after the inverse problem is solved. The second approach provides a tremendous advantage in solving the inverse problem, particularly in 3d applications, and it is recommended as the method of choice for this class of problems. It can be noted that the ga reconstructed heat flux distributions are robust, yielding accurate results to both exact and error-laden inputs. In all cases in this study, results from experiments are simulated using a full conjugate heat transfer (cht) finite volume models which incorporate the interactions of the external convection in the hot turbulent gas, internal convection within the cooling plena, and the heat conduction in the metal endwall/shroud region. Extensive numerical investigations are undertaken to demonstrate the significant importance of conjugate heat transfer in film cooling applications and to identify the implications of various turbulence models in the prediction of accurate and more realistic surface temperatures and heat fluxes in the cht simulations. These, in turn, are used to provide numerical inputs to the inverse problem. Single and multiple cooling slots, cylindrical cooling holes, and fan-shaped cooling holes are considered in this study. The turbulence closure is modeled using several two-equation approach, the four-equation turbulence model, as well as five and seven moment reynolds stress models. The predicted results, by the different turbulence models, for the cases of adiabatic and conjugate models, are compared to experimental data reported in the open literature. Results show the significant effects of conjugate heat transfer on the temperature field in the film cooling hole region, and the additional heating up of the cooling jet itself. Moreover, results from the detailed numerical studies presented in this study validate the inverse problem approaches and reveal good agreement between the bem/ga reconstructed heat fluxes and the cht simulated heat fluxes along the inaccessible cooling slot/hole walls
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Date Issued: 2004
Identifier: CFE0000166, ucf:52896
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000166

Title: The Heralds of the Dawn: A History of the Motion Picture Industry in the State of Florida, 1908-2019.
Creator: Morton, David, Foster, Amy, French, Scot, Zhang, Hong, University of Central Florida
Abstract / Description: Often overlooked in its contribution to cinema history, the State of Florida has the distinction of being among just a handful of regions in the United States to have a continuous connection with the American motion picture industry. This relationship in turn has produced iconic entertainment that has shaped the state's image to the outside world, while production spending has served as an important booster for local economies across Florida. The purpose of this study is to demonstrate how...
Show moreOften overlooked in its contribution to cinema history, the State of Florida has the distinction of being among just a handful of regions in the United States to have a continuous connection with the American motion picture industry. This relationship in turn has produced iconic entertainment that has shaped the state's image to the outside world, while production spending has served as an important booster for local economies across Florida. The purpose of this study is to demonstrate how the sometimes cooperative and often contentious dynamics between film and television producers and state politicians have influenced this history of film production in Florida. This can best be understood by examining the ideological divide between the pro-business and anti-corporate factions in Florida's government. Through a series of interconnected case studies that apply place-based analysis, this project demonstrates how the Florida government and communities have historically interacted with the motion picture industry. While Florida never truly became an (")Almost Hollywood(") or (")Hollywood East,(") film producers and state officials were at various times successful in turning the cities of Jacksonville, Tampa, Orlando, and Miami into important centers for film and television production. Yet just as each of these production hubs gained momentum, resistance at the state and local level resulted in the industry's decline and departure. These moments of cooperation and conflict provide important insights into the specific environmental characteristics that inspired filmmakers to come to Florida, as well as the social-political circumstances that eventually pushed them from the state. With a close scrutiny of trade press sources, periodicals, local newspapers, and the personal papers of filmmakers and politicians, this work explains the varied reasons behind the repeated rise, fall, and occasional exodus of the state's motion picture industry. This will be achieved by scrutinizing examples that range from policy decisions made by Florida's government from the turn of the twentieth century on through to the current efforts being made by Florida lawmakers to reinvigorate the state's production industry.
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Date Issued: 2019
Identifier: CFE0007505, ucf:52630
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007505

Title: Surface Acoustic Wave (SAW) Cryogenic Liquid and Hydrogen Gas Sensors.
Creator: Fisher, Brian, Malocha, Donald, Gong, Xun, Likamwa, Patrick, Richie, Samuel, Youngquist, Robert, University of Central Florida
Abstract / Description: This research was born from NASA Kennedy Space Center's (KSC) need for passive, wireless and individually distinguishable cryogenic liquid and H2 gas sensors in various facilities. The risks of catastrophic accidents, associated with the storage and use of cryogenic fluids may be minimized by constant monitoring. Accidents involving the release of H2 gas or LH2 were responsible for 81% of total accidents in the aerospace industry. These problems may be mitigated by the implementation of a...
Show moreThis research was born from NASA Kennedy Space Center's (KSC) need for passive, wireless and individually distinguishable cryogenic liquid and H2 gas sensors in various facilities. The risks of catastrophic accidents, associated with the storage and use of cryogenic fluids may be minimized by constant monitoring. Accidents involving the release of H2 gas or LH2 were responsible for 81% of total accidents in the aerospace industry. These problems may be mitigated by the implementation of a passive (or low-power), wireless, gas detection system, which continuously monitors multiple nodes and reports temperature and H2 gas presence. Passive, wireless, cryogenic liquid level and hydrogen (H2) gas sensors were developed on a platform technology called Orthogonal Frequency Coded (OFC) surface acoustic wave (SAW) radio frequency identification (RFID) tag sensors. The OFC-SAW was shown to be mechanically resistant to failure due to thermal shock from repeated cycles between room to liquid nitrogen temperature. This suggests that these tags are ideal for integration into cryogenic Dewar environments for the purposes of cryogenic liquid level detection. Three OFC-SAW H2 gas sensors were simultaneously wirelessly interrogated while being exposed to various flow rates of H2 gas. Rapid H2 detection was achieved for flow rates as low as 1ccm of a 2% H2, 98% N2 mixture. A novel method and theory to extract the electrical and mechanical properties of a semiconducting and high conductivity thin-film using SAW amplitude and velocity dispersion measurements were also developed. The SAW device was shown to be a useful tool in analysis and characterization of ultrathin and thin films and physical phenomena such as gas adsorption and desorption mechanisms.?
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Date Issued: 2012
Identifier: CFE0004536, ucf:49258
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004536

Title: INVESTIGATION OF REACTIVELY SPUTTERED BORON CARBON NITRIDE THIN FILMS.
Creator: Todi, Vinit, Sundaram, Kalpathy, University of Central Florida
Abstract / Description: Research efforts have been focused in the development of hard and wear resistant coatings over the last few decades. These protective coatings find applications in the industry such as cutting tools, automobile and machine part etc. Various ceramic thin films like TiN, TiAlN, TiC, SiC and diamond-like carbon (DLC) are examples of the films used in above applications. However, increasing technological and industrial demands request thin films with more complicated and advanced properties. For...
Show moreResearch efforts have been focused in the development of hard and wear resistant coatings over the last few decades. These protective coatings find applications in the industry such as cutting tools, automobile and machine part etc. Various ceramic thin films like TiN, TiAlN, TiC, SiC and diamond-like carbon (DLC) are examples of the films used in above applications. However, increasing technological and industrial demands request thin films with more complicated and advanced properties. For this purpose, B-C-N ternary system which is based on carbon, boron and nitrogen which exhibit exceptional properties and attract much attention from mechanical, optical and electronic perspectives. Also, boron carbonitride (BCN) thin films contains interesting phases such as diamond, cubic BN (c-BN), hexagonal boron nitride (h-BN), B4C, [two]-C3N4. Attempts have been made to form a material with semiconducting properties between the semi metallic graphite and the insulating h-BN, or to combine the cubic phases of diamond and c-BN (BC2N heterodiamond) in order to merge the higher hardness of the diamond with the advantages of c-BN, in particular with its better chemical resistance to iron and oxygen at elevated temperatures. New microprocessor CMOS technologies require interlayer dielectric materials with lower dielectric constant than those used in current technologies to meet RC delay goals and to minimize cross-talk. Silicon oxide or fluorinated silicon oxide (SiOF) materials having dielectric constant in the range of 3.6 to 4 have been used for many technology nodes. In order to meet the aggressive RC delay goals, new technologies require dielectric materials with K<3. BCN shows promise as a low dielectric constant material with good mechanical strength suitable to be used in newer CMOS technologies. For optical applications, the deposition of BCN coatings on polymers is a promising method for protecting the polymer surface against wear and scratching. BCN films have high optical transparency and thus can be used as mask substrates for X-ray lithography. Most of the efforts from different researchers were focused to deposit cubic boron nitride and boron carbide films. Several methods of preparing boron carbon nitride films have been reported, such as chemical vapor deposition (CVD), plasma assisted CVD, pulsed laser ablation and ion beam deposition. Very limited studies could be found focusing on the effect of nitrogen incorporation into boron carbide structure by sputtering. In this work, the deposition and characterization of amorphous thin films of boron carbon nitride (BCN) is reported. The BCN thin films were deposited by radio frequency (rf) magnetron sputtering system. The BCN films were deposited by sputtering from a high purity B4C target with the incorporation of nitrogen gas in the sputtering ambient. Films of different compositions were deposited by varying the ratios of argon and nitrogen gas in the sputtering ambient. Investigation of the oxidation kinetics of these materials was performed to study high temperature compatibility of the material. Surface characterization of the deposited films was performed using X-ray photoelectron spectroscopy and optical profilometry. Studies reveal that the chemical state of the films is highly sensitive to nitrogen flow ratios during sputtering. Surface analysis shows that smooth and uniform BCN films can be produced using this technique. Carbon and nitrogen content in the films seem to be sensitive to annealing temperatures. However depth profile studies reveal certain stoichiometric compositions to be stable after high temperature anneal up to 700[degrees]C. Electrical and optical characteristics are also investigated with interesting results. The optical band gap of the films ranged from 2.0 eV - 3.1 eV and increased with N2/Ar gas flow ratio except at the highest ratio. The optical band gap showed an increasing trend when annealed at higher temperatures. The effect of deposition temperature on the optical and chemical compositions of the BCN films was also studied. The band gap increased with the deposition temperature and the films deposited at 500oC had the highest band gap. Dielectric constant was calculated from the Capacitance-Voltage curves obtained for the MOS structures with BCN as the insulating material. Aluminum was used as the top electrode and the substrate was p-type Si. Effect of N2/Ar gas flow ratio and annealing on the values of dielectric constant was studied and the dielectric constant of 2.5 was obtained for the annealed BCN films. This by far is the lowest value of dielectric constant reported for BCN film deposited by sputtering. Lastly, the future research work on the BCN films that will be carried out as a part of the dissertation is proposed.
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Date Issued: 2011
Identifier: CFE0004033, ucf:49181
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004033

Title: Heat Transfer in a Coupled Impingement-Effusion Cooling System.
Creator: Miller, Mark, Kapat, Jayanta, Deng, Weiwei, Gordon, Ali, University of Central Florida
Abstract / Description: The efficiency of air-breathing gas turbine engines improves as the combustion temperature increases. Therefore, modern gas turbines operate at temperatures greater than the melting temperature of hot-gas-path components, and cooling must be introduced in order to maintain mechanical integrity of those components. Two highly effective techniques used in modern designs for this purpose are impingement cooling and use of coolant film on hot-gas-path surface introduced through discrete film or...
Show moreThe efficiency of air-breathing gas turbine engines improves as the combustion temperature increases. Therefore, modern gas turbines operate at temperatures greater than the melting temperature of hot-gas-path components, and cooling must be introduced in order to maintain mechanical integrity of those components. Two highly effective techniques used in modern designs for this purpose are impingement cooling and use of coolant film on hot-gas-path surface introduced through discrete film or effusion holes. In this study, these two mechanisms are coupled into a single prototype cooling system. The heat transfer capability of this system is experimentally determined for a variety of different geometries and coolant flow rates.This study utilizes Temperature Sensitive Paint (TSP) in order to measure temperature distribution over a surface, which allowed for local impingement Nusselt number, film cooling effectiveness, and film cooling heat transfer enhancement profiles to be obtained. In addition to providing quantitative heat transfer data, this method allowed for qualitative investigation of the flow behavior near the test surface. Impinging jet-to-target-plate spacing was varied over a large range, including several tall impingement scenarios outside the published limits. Additionally, both in-line and staggered effusion arrangements were studied, and results for normal injection were compared to full coverage film cooling with inclined- and compound-angle injection. Effects of impingement and effusion cooling were combined to determine the overall cooling effectiveness of the system.It is shown that low impingement heights produce the highest Nusselt number, and that large jet-to-jet spacing reduces coolant flow rate while maintaining moderate to high heat transfer rates. Staggered effusion configurations exhibit superior performance to in-line configurations, as jet interference is reduced and surface area coverage is improved. Coolant to mainstream flow mass flux ratios greater than unity result in jet blow-off and reduced effectiveness. The convective heat transfer coefficient on the film cooled surface is higher than a similar surface without coolant injection due to the generation of turbulence associated with jet-cross flow interaction.
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Date Issued: 2011
Identifier: CFE0004140, ucf:49042
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004140

Title: EPITAXIAL GROWTH, CHARACTERIZATION AND APPLICATION OF NOVEL WIDE BANDGAP OXIDE SEMICONDUCTORS.
Creator: Mares, Jeremy, Schoenfeld, Winston, University of Central Florida
Abstract / Description: In this work, a body of knowledge is presented which pertains to the growth, characterization and exploitation of high quality, novel II-IV oxide epitaxial films and structures grown by plasma-assisted molecular beam epitaxy. The two compounds of primary interest within this research are the ternary films NixMg1-xO and ZnxMg1-xO and the investigation focuses predominantly on the realization, assessment and implementation of these two oxides as optoelectronic materials. The functioning...
Show moreIn this work, a body of knowledge is presented which pertains to the growth, characterization and exploitation of high quality, novel II-IV oxide epitaxial films and structures grown by plasma-assisted molecular beam epitaxy. The two compounds of primary interest within this research are the ternary films NixMg1-xO and ZnxMg1-xO and the investigation focuses predominantly on the realization, assessment and implementation of these two oxides as optoelectronic materials. The functioning hypothesis for this largely experimental effort has been that these cubic ternary oxides can be exploited - and possibly even juxtaposed - to realize novel wide band gap optoelectronic technologies. The results of the research conducted presented herein overwhelmingly support this hypothesis in that they confirm the possibility to grow these films with sufficient quality by this technique, as conjectured. NixMg1-xO films with varying Nickel concentrations ranging from x = 0 to x = 1 have been grown on lattice matched MgO substrates (lattice mismatch ε < 0.01) and characterized structurally, morphologically, optically and electrically. Similarly, cubic ZnxMg1-xO films with Zinc concentrations ranging from x = 0 to x ≈ 0.53, as limited by phase segregation, have also been grown and characterized. Photoconductive devices have been designed and fabricated from these films and characterized. Successfully engineered films in both categories exhibit the desired deep ultraviolet photoresponse and therefore verify the hypothesis. While the culminating work of interest here focuses on the two compounds discussed above, the investigation has also involved the characterization or exploitation of related films including hexagonal phase ZnxMg1-xO, ZnO, CdxZn1-xO and hybrid structures based on these compounds used in conjunction with GaN. These works were critical precursors to the growth of cubic oxides, however, and are closely relevant. Viewed in its entirety, this document can therefore be considered a multifaceted interrogation of several novel oxide compounds and structures, both cubic and wurtzite in structure. The conclusions of the research can be stated succinctly as a quantifiably successful effort to validate the use of these compounds and structures for wide bandgap optoelectronic technologies.
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Date Issued: 2010
Identifier: CFE0003125, ucf:48625
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003125

Title: CHARACTERIZATION OF ALUMINUM DOPED ZINC OXIDE THIN FILMS FOR PHOTOVOLTAIC APPLICATIONS.
Creator: Shantheyanda, Bojanna, Kalpathy, Sundaram, University of Central Florida
Abstract / Description: Growing demand for clean source of energy in the recent years has increased the manufacture of solar cells for converting sun energy directly into electricity. Research has been carried out around the world to make a cheaper and more efficient solar cell technology by employing new architectural designs and developing new materials to serve as light absorbers and charge carriers. Aluminum doped Zinc Oxide thin film, a Transparent conductive Oxides (TCO) is used as a window material in the...
Show moreGrowing demand for clean source of energy in the recent years has increased the manufacture of solar cells for converting sun energy directly into electricity. Research has been carried out around the world to make a cheaper and more efficient solar cell technology by employing new architectural designs and developing new materials to serve as light absorbers and charge carriers. Aluminum doped Zinc Oxide thin film, a Transparent conductive Oxides (TCO) is used as a window material in the solar cell these days. Its increased stability in the reduced ambient, less expensive and more abundance make it popular among the other TCOÃ‚Â's. It is the aim of this work to obtain a significantly low resistive ZnO:Al thin film with good transparency. Detailed electrical and materials studies is carried out on the film in order to expand knowledge and understanding. RF magnetron sputtering has been carried out at various substrate temperatures using argon, oxygen and hydrogen gases with various ratios to deposit this polycrystalline films on thermally grown SiO2 and glass wafer. The composition of the films has been determined by X-ray Photoelectron Spectroscopy and the identification of phases present have been made using X-ray diffraction experiment. Surface imaging of the film and roughness calculations are carried out using Scanning Electron Microscopy and Atomic Force Microscopy respectively. Determination of resistivity using 4-Probe technique and transparency using UV spectrophotometer were carried out as a part of electrical and optical characterization on the obtained thin film.The deposited thin films were later annealed in vacuum at various high temperatures and the change in material and electrical properties were analyzed.
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Date Issued: 2010
Identifier: CFE0003142, ucf:48623
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003142

Title: THE DEVELOPMENT OF THE UNIVERSITY OF CENTRAL FLORIDA HOME MOVIE ARCHIVE AND THE HARRIS ROSEN COLLECTION.
Creator: Niedermeyer, Michael, Gordon, Fon, University of Central Florida
Abstract / Description: Since the invention of the cinema, people have been taking home movies. The ever increasing popularity of this activity has produced a hundred years worth of amateur film culture which is in desperate need of preservation. As film archival and public history have coalesced in the past thirty years around the idea that every personÃ‚Â's history is important, home movies represent a way for those histories to be preserved and studied by communities and researchers alike....
Show moreSince the invention of the cinema, people have been taking home movies. The ever increasing popularity of this activity has produced a hundred years worth of amateur film culture which is in desperate need of preservation. As film archival and public history have coalesced in the past thirty years around the idea that every personÃ‚Â's history is important, home movies represent a way for those histories to be preserved and studied by communities and researchers alike. The University of Central Florida is in a perfect position to establish an archive of this nature, one that is specifically dedicated to acquiring, preserving, and presenting the home movies of Central Florida residents. This project has resulted in the establishment of The Central Florida Home Movie Archive, and the resulting analysis will show that the archive will be a benefit for researchers from all areas of academic study as well as the residents of Central Florida.
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Date Issued: 2010
Identifier: CFE0003432, ucf:48410
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003432

Title: BAD PIXELS: CHALLENGES OF MICROBUDGET DIGITAL CINEMA.
Creator: Bowser, Alexander, Stoeckl, Ula, University of Central Florida
Abstract / Description: Bad Pixels is a feature-length, microbudget, digital motion picture, produced, written, and directed by Alexander Jon Bowser as part of the requirements for earning a Master of Fine Arts in Film & Digital Media from the University of Central Florida. The materials contained herein serve as a record of the microbudget filmmaking experience. This thesis documents the challenges confronted by a first-time feature filmmaker; an evaluation of both the theory and application of a dynamic...
Show moreBad Pixels is a feature-length, microbudget, digital motion picture, produced, written, and directed by Alexander Jon Bowser as part of the requirements for earning a Master of Fine Arts in Film & Digital Media from the University of Central Florida. The materials contained herein serve as a record of the microbudget filmmaking experience. This thesis documents the challenges confronted by a first-time feature filmmaker; an evaluation of both the theory and application of a dynamic microbudget approach to digital content creation. From script development to digital distribution, the thesis aims to reflect on technical and procedural decisions made and assess their impact on the overall experience and final product.
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Date Issued: 2011
Identifier: CFE0003729, ucf:48767
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003729

Title: Wise the Wizard: A Feature Documentary about the Late Harry Wise of Sanford, Florida.
Creator: Blakelock, Daisy, Mills, Lisa, Jones, Robert, Danker, Elizabeth, University of Central Florida
Abstract / Description: Wise the Wizard is a feature-length documentary by Daisy Sara Blakelock, made as part of the requirements for earning a Master of Fine Arts in Entrepreneurial Digital Cinema from the University of Central Florida. The film focuses on the late Harry Wise, a magician from Sanford, Florida, as remembered by the people who knew him best. Interview subjects include the following: author and TV Producer Charlie Carlson, who wrote a biography about Harry Wise entitled A Wizard's Tux and Tales ...
Show moreWise the Wizard is a feature-length documentary by Daisy Sara Blakelock, made as part of the requirements for earning a Master of Fine Arts in Entrepreneurial Digital Cinema from the University of Central Florida. The film focuses on the late Harry Wise, a magician from Sanford, Florida, as remembered by the people who knew him best. Interview subjects include the following: author and TV Producer Charlie Carlson, who wrote a biography about Harry Wise entitled A Wizard's Tux and Tales (Luthers Press, New Smyrna Beach: 2004); Brendan and Anna McWilliams, who accompanied Harry on countless adventures throughout Sanford and the surrounding areas; Art Litka, who dedicated a portion of his Halloween Village to Harry Wise; filmmaker and magician Gary Lester, who studied magic under Harry Wise and acquired and restored many of Harry's former props; and Lynn Ashe, Harry Wise's best friend.
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Date Issued: 2015
Identifier: CFE0005925, ucf:50839
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005925

Title: Characteristics of Hydrogel-Wetted Thin Films.
Creator: Owens, James, Putnam, Shawn, Chow, Louis, Xu, Yunjun, University of Central Florida
Abstract / Description: The meniscus region of a thin film is known to have high heat transfer properties due to high evaporation rates and activation of latent heat. The region known as the thin film meniscus (?_film(
Show moreThe meniscus region of a thin film is known to have high heat transfer properties due to high evaporation rates and activation of latent heat. The region known as the thin film meniscus (?_film(<)2 (&)#181;m ) can account for more than half of the total heat transfer of a droplet or film. This study focuses on the potential elongation and curvature amplification of the thin film meniscus region by the implementation of a layer of high hydrogen bonding (hydrogel) film on which the liquid meniscus is built. Forced wetting via liquid propagation though this hydrogel layer in the radial direction increases the surface area of the film. By analyzing the mass flux of liquid lost through evaporation and using both spectroscopic and optical methods to obtain the curvature of the film, relationships between hydrogel thickness and the resulting mass flux were made. Isothermal and steady state assumptions were used to relate hydrogel thickness layers to meniscus curvature, evaporative mass flux, and overall heat transfer coefficients. The experimental results demonstrate, that steady state conditions are achievable with small percentage change in film profile over time. These results are promising toward the addition of the hydrogel coatings and further advancements in heat piping and high heat flux cooling systems for micro electronic devices.
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Date Issued: 2017
Identifier: CFE0006634, ucf:51257
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006634

Title: Performance optimization of lateral-mode thin-film piezoelectric-on-substrate resonant systems.
Creator: Fatemi, Hedy, Abdolvand, Reza, Sundaram, Kalpathy, Malocha, Donald, Gong, Xun, Cho, Hyoung Jin, University of Central Florida
Abstract / Description: The main focus of this dissertation is to characterize and improve the performance of thin-film piezoelectric-on-substrate (TPoS) lateral-mode resonators and filters. TPoS is a class of piezoelectric MEMS devices which benefits from the high coupling coefficient of the piezoelectric transduction mechanism while taking advantage of superior acoustic properties of a substrate. The use of lateral-mode TPoS designs allows for fabrication of dispersed-frequency filters on a single substrate, thus...
Show moreThe main focus of this dissertation is to characterize and improve the performance of thin-film piezoelectric-on-substrate (TPoS) lateral-mode resonators and filters. TPoS is a class of piezoelectric MEMS devices which benefits from the high coupling coefficient of the piezoelectric transduction mechanism while taking advantage of superior acoustic properties of a substrate. The use of lateral-mode TPoS designs allows for fabrication of dispersed-frequency filters on a single substrate, thus significantly reducing the size and manufacturing cost of devices. TPoS filters also offer a lower temperature coefficient of frequency, and better power handling capability compared to rival technologies all in a very small footprint.Design and fabrication process of the TPoS devices is discussed. Both silicon and diamond substrates are utilized for fabrication of TPoS devices and results are compared. Specifically, the superior acoustic properties of nanocrystalline diamond in scaling the frequency and energy density of the resonators is highlighted in comparison with silicon. The performance of TPoS devices in a variety of applications is reported. These applications include lateral-mode TPoS filters with record low IL values (as low as 2dB) and fractional bandwidth up to 1%, impedance transformers, very low phase noise oscillators, and passive wireless temperature sensors.
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Date Issued: 2015
Identifier: CFE0005945, ucf:50805
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005945

film (20)	+ -
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digital (7)	+ -
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cinema (6)	+ -
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Experimental (4)	+ -
documentary (4)	+ -
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horror (4)	+ -
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Cu (3)	+ -
Digital Cinema (3)	+ -
Documentary (3)	+ -
Filmmaking (3)	+ -
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