Current Search: French, Middle (ca.1400-1600) (x) » Cartoons (Commentary) (x)
View All Items
Pages
- Title
- Noise Thinks the Anthropocene: An Experiment in Noise Poetics.
- Creator
-
Zwintscher, Aaron, Mauer, Barry, Grajeda, Anthony, Rounsaville, Angela, Schafer, Mark, University of Central Florida
- Abstract / Description
-
This dissertation is a textual experiment in noise poetics. It is an experiment in that it results from indeterminate means, alternative grammar, and experimental thinking. The outcome was not predetermined. Noise poetics is the use of noise to explain, elucidate, and evoke (akin to other poetic forms) within the textual milieu in a manner that seeks to be less determinate and more improvisational than conventional writing. This text argues that noise poetics is a necessary form for...
Show moreThis dissertation is a textual experiment in noise poetics. It is an experiment in that it results from indeterminate means, alternative grammar, and experimental thinking. The outcome was not predetermined. Noise poetics is the use of noise to explain, elucidate, and evoke (akin to other poetic forms) within the textual milieu in a manner that seeks to be less determinate and more improvisational than conventional writing. This text argues that noise poetics is a necessary form for addressing political inequality, coexistence with the (nonhuman) other, the ecological crisis, and sustainability because it approaches these issues as system of interconnected fragments and excesses and thus has the potential to reach or envision solutions in novel ways. The experiment draws quotations and fragments from a diverse collection of noise theory texts, arranged and assembled via indeterminate cut-up methods based on the work of several prominent artists and theorists (John Cage and William Burroughs among them). The experimental text (contained in full in Appendix B) was then edited and added to in order to craft the textual project into an argument for noise poetics that followed the juxtaposed lines of thought towards possible conclusions and practical applications. This project coincided with and was supplemented by bruit jouissance, a multimedia audiovisual noise project (contained and explicated in Appendix A). The two projects together are two applications of thoryvology (an articulation of noise theory created and presented within the text) and as complementary methods of viewing and understanding each other.
Show less - Date Issued
- 2017
- Identifier
- CFE0006679, ucf:51911
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006679
- Title
- Mechanism of Hip Dysplasia and Identification of the Least Energy Path for its Treatment by using the Principle of Stationary Potential Energy.
- Creator
-
Zwawi, Mohammed abdulwahab m, Moslehy, Faissal, Kassab, Alain, Mansy, Hansen, Divo, Eduardo, University of Central Florida
- Abstract / Description
-
Developmental dysplasia of the hip (DDH) is a common newborn condition where the femoral head is not located in its natural position in the acetabulum (hip socket). Several treatment methods are being implemented worldwide to treat this abnormal condition. One of the most effective methods of treatment is the use of Pavlik Harness, which directs the femoral head toward the natural position inside the acetabulum. This dissertation presents a developed method for identifying the least energy...
Show moreDevelopmental dysplasia of the hip (DDH) is a common newborn condition where the femoral head is not located in its natural position in the acetabulum (hip socket). Several treatment methods are being implemented worldwide to treat this abnormal condition. One of the most effective methods of treatment is the use of Pavlik Harness, which directs the femoral head toward the natural position inside the acetabulum. This dissertation presents a developed method for identifying the least energy path that the femoral head would follow during reduction. This is achieved by utilizing a validated computational biomechanical model that allows the determination of the potential energy, and then implementing the principle of stationary potential energy. The potential energy stems from strain energy stored in the muscles and gravitational potential energy of four rigid-body components of lower limb bones. Five muscles are identified and modeled because of their effect on DDH reduction. Clinical observations indicate that reduction with the Pavlik Harness occurs passively in deep sleep under the combined effects of gravity and the constraints of the Pavlik Harness.A non-linear constitutive equation, describing the passive muscle response, is used in the potential energy computation. Different DDH abnormalities with various flexion, abduction, and hip rotation angles are considered, and least energy paths are identified. Several constraints, such as geometry and harness configuration, are considered to closely simulate real cases of DDH. Results confirm the clinical observations of two different pathways for closed reduction. The path of least energy closely approximated the modified Hoffman-Daimler method. Release of the pectineus muscle favored a more direct pathway over the posterior rim of the acetabulum. The direct path over the posterior rim of the acetabulum requires more energy. This model supports the observation that Grade IV dislocations may require manual reduction by the direct path. However, the indirect path requires less energy and may be an alternative to direct manual reduction of Grade IV infantile hip dislocations. Of great importance, as a result of this work, identifying the minimum energy path that the femoral head would travel would provide a non-surgical tool that effectively aids the surgeon in treating DDH.?
Show less - Date Issued
- 2015
- Identifier
- CFE0006022, ucf:51000
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006022
- Title
- GETTING TO THE PULP OF HARUKI MURAKAMI'SNORWEGIAN WOOD:TRANSLATABILITY AND THE ROLE OF POPULAR CULTURE.
- Creator
-
Zuromski, Jacquelyn, Murphy, Patrick D., University of Central Florida
- Abstract / Description
-
Haruki Murakami's Norwegian Wood (1987) veers from his favored detective-fiction genre by offering readers a 1960s coming-of-age romance, a story whose plot nonetheless spins around the protagonist seeking out his personal identity. The conflicts between Japanese tradition and modern, global perspectives are illustrated through the inclusion of popular culture elements such as music, literature and films. This thesis seeks to show how the novel's references to popular culture of the 1960s...
Show moreHaruki Murakami's Norwegian Wood (1987) veers from his favored detective-fiction genre by offering readers a 1960s coming-of-age romance, a story whose plot nonetheless spins around the protagonist seeking out his personal identity. The conflicts between Japanese tradition and modern, global perspectives are illustrated through the inclusion of popular culture elements such as music, literature and films. This thesis seeks to show how the novel's references to popular culture of the 1960s combine to help the protagonist establish an identity for himself as well as his place within the universal community. First, though, the project explores the impact of the translatability issues that arise with each of the novel's two English translations, variations dictated by the needs of differing audiences. The introduction provides an overview of the study, as well as historical background pertinent to the understanding of the Sixties-era popular culture iconography privileged by Murakami. My methodology favors a cultural studies approach and utilizes reader response and reception theories. Separate chapters then compare specifics between the two translations and examine the functionality and significance of music, literature and film within the novel. The conclusion justifies the subsequent deviations between the translations and argues for the necessity and value of both English versions, but claims Rubin's as the definitive English translation. Likewise, the study of the novel's many popular culture references exemplifies the roles that music, books, and film play in the creation of the protagonist's individual identity in Norwegian Wood while simultaneously illustrating the effectiveness of using globally recognizable media as a bridge between cultures.
Show less - Date Issued
- 2004
- Identifier
- CFE0000258, ucf:46242
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000258
- Title
- EVALUATION OF THE IMPACTS OF ITS INFORMATION STRATEGIES ON I-4 CORRIDOR.
- Creator
-
Zuo, Yueliang, Al-Deek, Haitham M., University of Central Florida
- Abstract / Description
-
This study evaluated the impacts of ITS information strategies under incident conditions in Interstate 4 (I-4) corridor of Orlando. The analysis was performed using DYNASMART-P software package. The ITS information strategies range from pre-trip information, en-route information, and variable message signs. Simulation covered one hour during the morning peak period. The impacts of ITS information strategies on mobility were evaluated by simulating the performance of various ITS information...
Show moreThis study evaluated the impacts of ITS information strategies under incident conditions in Interstate 4 (I-4) corridor of Orlando. The analysis was performed using DYNASMART-P software package. The ITS information strategies range from pre-trip information, en-route information, and variable message signs. Simulation covered one hour during the morning peak period. The impacts of ITS information strategies on mobility were evaluated by simulating the performance of various ITS information components (pre-trip information, en-route information, and variable message signs) under incident conditions for the I-4 corridor and comparing the results with the corresponding scenarios in the absence of these components. The traffic flow relations were calibrated against the flow measurements along freeway to determine model parameters. An effort was made to validate estimated traffic volumes against measured link counts. The archived I-4 data at the Center for Advanced Transportation Systems Simulation (CATSS) at the University of Central Florida was used for both calibration and validation. The analysis indicated that DYNASMART-P was able to adequately reproduce the observed morning peak hourly flows over suitably selected locations.Ten scenarios were designed to evaluate the benefits of ITS information strategies under incident conditions. The results indicated that these ITS traveler information technologies can result in great travel time saving. It was found that commuters who use traveler information via the pre-trip information or en-route information to switch their routes benefit significantly in terms of delay reduction when incidents occur. It was found that there exists an optimal value for the fraction users with information at which the network performs best. This optimal fraction may be different for different source of information. Also this may vary with different incidents. This study demonstrates how one can realistically simulate the network under various scenarios without actually conducting the high cost operational tests. DYNASMART-P can produce useful variables such as speeds, travel time, queue lengths, and stop time to better assess the impacts of ITS components. It can be applied in ITS equipped networks.
Show less - Date Issued
- 2004
- Identifier
- CFE0000107, ucf:46199
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000107
- Title
- STUDY OF DISCHARGE COEFFICIENT AND TRENDS IN FILM COOLING EFFECTIVENESS OF CONICAL HOLES WITH INCREASING DIFFUSION ANGLES.
- Creator
-
Zuniga, Humberto, Kapat, Jayanta, University of Central Florida
- Abstract / Description
-
Previous studies indicate that increasing the diffusion angle in conical film-cooling holes leads to an improvement in their film cooling effectiveness. Discharge coefficient and film cooling effectiveness measurements are conducted to characterize this behavior. Part of the focus of this investigation is to find out how this trend develops and attempt to ascertain the optimum cone angle, if possible. Six test plates, each with one row of eight conical-shaped cooling holes of equal diffusion...
Show morePrevious studies indicate that increasing the diffusion angle in conical film-cooling holes leads to an improvement in their film cooling effectiveness. Discharge coefficient and film cooling effectiveness measurements are conducted to characterize this behavior. Part of the focus of this investigation is to find out how this trend develops and attempt to ascertain the optimum cone angle, if possible. Six test plates, each with one row of eight conical-shaped cooling holes of equal diffusion angles of 0, 1, 2, 3, 6, or 8º, with respect to the hole axis are used in this study. The ratios of the hole exit areas to the inlet areas range from 1 to 2.85. Coolant injection angle for all holes is at 35 degrees to the horizontal, in the direction of the main flow. Coefficients of discharge of all holes are reported under flow conditions. Temperature sensitive paint, TSP, is the technique used to find the temperature distribution downstream of the cooling holes and determine the laterally averaged film-cooling effectiveness. Data are obtained for blowing ratios ranging from 0.5 to 1.5, at a constant density ratio of 1.26. Results and trends are compared with established literature, which also recommends that a cylindrical entry length for diffused holes should be at least 4 diameters long. The effect that an added entry length has on the 3-degree conical plate's cooling effectiveness is also explored. Data are compared to baseline cylindrical holes, as well as to fan-shaped film holes found in open literature. Results indicate that the conical holes with larger diffusion angles provide strikingly even film protection and outperform fan shaped and cylindrical holes under certain conditions over extended downstream distances. Also, the addition of a cylindrical entry length to a conical hole, by providing a manageable metering diameter, should ease their usage while providing the full benefits of the conical geometry which may one day lead to numerous industrial applications.
Show less - Date Issued
- 2006
- Identifier
- CFE0001492, ucf:47087
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001492
- Title
- STUDY OF FILM COOLING EFFECTIVENESS: CONICAL, TRENCHED AND ASYMMETRICAL SHAPED HOLES.
- Creator
-
Zuniga, Humberto, Kapat, Jayanta, University of Central Florida
- Abstract / Description
-
Film cooling is a technique whereby air from the compressor stage of a gas turbine engine is diverted for cooling purposes to parts, such as the turbine stage, that operate at very high temperatures. Cooling arrangements include impingement jets, finned, ribbed and turbulated channels, and rows of film cooling holes, all of which over the years have become progressively more complex. This costly, but necessary complexity is a result of the industry's push to run engines at increasingly higher...
Show moreFilm cooling is a technique whereby air from the compressor stage of a gas turbine engine is diverted for cooling purposes to parts, such as the turbine stage, that operate at very high temperatures. Cooling arrangements include impingement jets, finned, ribbed and turbulated channels, and rows of film cooling holes, all of which over the years have become progressively more complex. This costly, but necessary complexity is a result of the industry's push to run engines at increasingly higher turbine inlet temperatures. Higher temperatures mean higher efficiency, but they also mean that the turbine first stage operates hundreds of degrees Kelvin above the melting point of the metal core of the vanes and blades. Existing cooling technology and materials make it possible to protect these parts and allow them to function for extended periods of time--but this comes at a price: the compressed air that is used for cooling represents a considerable penalty in overall turbine efficiency. The aim of current cooling research is threefold: to improve the protection of components from extreme fluxes in order to extend the life of the parts; to increase the inlet turbine operating temperature; and to reduce the amount of air that is diverted from the compressor for cooling. Current film cooling schemes consist of forcing air through carefully machined holes on a part and ejecting it at an angle with the intent of cooling that part by blanketing the surface downstream of the point of ejection. The last major development in the field has been the use of expanded hole exits, which reduce coolant momentum and allow for greater surface coverage. Researchers and designers are continuously looking for novel geometries and arrangements that would increase the level of protection or maintain it while using less coolant. This dissertation investigates such novel methods which one day may include combinations of cylindrical and fan-shaped holes embedded inside trenches, conical holes, or even rows of asymmetric fan-shaped holes. The review of current literature reveals that very few investigations have been done on film cooling effectiveness for uniformly diffusing conical holes. They have been treated as a sort of side novelty since industrial partners often say they are hard to manufacture. To extend our understanding of effectiveness of conical holes, the present study investigates the effect of increasing diffusion angle, as well as the effect of adding a cylindrical entrance length to a conical hole. The measurements were made in the form of film cooling effectiveness and the technique used was temperature sensitive paint. Eight different conical geometries were tested in the form of coupons with rows of holes. The geometry of the holes changed from pure cylindrical holes, a 0° cylindrical baseline, to an 8° pure cone. The coupons were tested in a closed loop wind tunnel at blowing ratios varying from 0.5 to 1.5, and the coolant employed was nitrogen gas. Results indicate that the larger conical holes do, in fact offer appropriate protection and that the holes with the higher expansion angles perform similar to fan-shaped baseline holes, even at the higher blower ratios. The study was also extended to two other plates in which the conical hole was preceded by a cylindrical entry length. The performance of the conical holes improves as a result of the entry length and this is seen at the higher blowing ratios in the form of a delay in the onset of jet detachment. The results of this study show that conical expanding holes are a viable geometry and that their manufacturing can be made easier with a cylindrical entry length, at the same time improving the performance of these holes. Trench cooling consists of having film cooling holes embedded inside a gap, commonly called a trench. The walls of this gap are commonly vertical with respect to the direction of the main flow and are directly in the path of the coolant. The coolant hits the downstream trench wall which forces it to spread laterally, resulting in more even film coverage downstream than that of regular holes flush with the surface. Recent literature has focused on the effect that trenching has on cylindrical cooling holes only. While the results indicate that trenches are an exciting, promising new geometry derived from the refurbishing process of thermal barrier ceramic coatings, not all the parameters affecting film cooling have been investigated relating to trenched holes. For example, nothing has been said about how far apart holes inside the trench will need to be placed for them to stop interacting. Nothing has been said about shaped holes inside a trench, either. This dissertation explores the extent to which trenching is useful by expanding the PI/D from 4 to 12 for rows of round and fan holes. In addition the effect that trenching has on fan-shaped holes is studied by systematically increasing the trench depth. Values of local, laterally-averaged and spatially-averaged film cooling effectiveness are reported. It is found that placing the cylinders inside the trench and doubling the distance between the holes provides better performance than the cylindrical, non-trenched baseline, especially at the higher blowing ratios, M > 1.0. At these higher coolant flow rates, the regular cylindrical jets show detachment, while those in the trench do not. They, in fact perform very well. The importance of this finding implies that the number of holes, and coolant, can be cut in half while still improving performance over regular holes. The trenched cylindrical holes did not, however, perform like the fan shaped holes. It was found that the performance of fan-shaped holes inside trenches is actually diminished by the presence of the trench. It is obvious, since the fan diffuses the flow, reducing the momentum of the coolant; the addition of the trench further slows the flow down. This, in turn, leads to the quicker ingestion of the main flow by the jets resulting in lower effectiveness. The next part of the study consisted of systematically increasing the depth of the trench for the fan-shaped holes. The purpose of this was to quantify the effect of the trench on the film cooling effectiveness. It was found that the presence of the trench significantly reduces the film effectiveness, especially for the deeper cases. At the higher blowing ratios, the overall performance of the fans collapses to the same value signifying insensitivity to the blowing ratio. A recent study suggests that having a compound angle could reduce the protective effect of the film due to the elevated interaction between the non-co-flowing coolant jet and the mainstream. Although it has been suggested that a non-symmetric lateral diffusion could mitigate the ill effects of having a compound angle, little has been understood on the effect this non-symmetry has on film cooling effectiveness. The last part of this study investigates the effect of non-symmetric lateral diffusion on film cooling effectiveness by systematically varying one side of a fan-shaped hole. For this part of the study, one of the lateral angles of diffusion of a fan-shaped hole was changed from 5° to 13°, while the other side was kept at 7°. It was found that a lower angle of diffusion hurts performance, while a larger diffusion angle improves it. However, the more significant result was that the jet seemed to be slightly turning. This suggests that the jets actually have two regions: one region with reduced momentum, ideal for protecting a large area downstream of the point of injection; and another region with more integrity which could withstand more aggressive main flow conditions. A further study should be conducted for this geometry at compound angles with the main flow to test this theory. The studies conducted show that the temperature sensitive paint technique can be used to study the performance of film cooling holes for various geometries. The studies also show the film cooling performance of novel geometries and explain why, in some cases, such new arrangements are desirable, and in others, how they can hurt performance. The studies also point in the direction of further investigations in order to advance cooling technology to more effective applications and reduced coolant consumption, the main goal of applied turbine cooling research.
Show less - Date Issued
- 2009
- Identifier
- CFE0002831, ucf:48082
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002831
- Title
- Computational Approach to the Problems of Electro- and Photo-Catalysis.
- Creator
-
Zuluaga, Sebastian, Stolbov, Sergey, Schelling, Patrick, Roldan Cuenya, Beatriz, Masunov, Artem, University of Central Florida
- Abstract / Description
-
The main objective of this work is to gain basis for rational design of catalysts used in fuel cells for conversion of chemical energy stored in hydrogen molecules into electric energy, as well as photo-catalysts used for hydrogen production from water under solar irradiation. This objective is achieved by applying the first principles computational approach to reveal relationship among compositions of materials under consideration, their electronic structure and catalytic activity. A major...
Show moreThe main objective of this work is to gain basis for rational design of catalysts used in fuel cells for conversion of chemical energy stored in hydrogen molecules into electric energy, as well as photo-catalysts used for hydrogen production from water under solar irradiation. This objective is achieved by applying the first principles computational approach to reveal relationship among compositions of materials under consideration, their electronic structure and catalytic activity. A major part of the work is focused on electro-catalysts for hydrogen fuel cells. Platinum (Pt) is widely used in the electrodes of fuel cells due to its good catalytic properties. However, Pt is an expensive and scarce element, its catalytic activity is not optimal and also it suffers from CO poisoning at anode. Therefore the search for new catalytic materials is needed for large scale implementation of fuel cells. The main direction of search of more efficient electro-catalysts is based in the design in which an active element monoatomic layer (AE) is deposited on a metal substrate (MS) made of a cost-effective material. Two goals are achieved by doing this: on the one hand, the cost of the catalytic system is reduced by reducing the amount of the AE in the system and on the other hand the catalytic properties of the AE can be tuned through its interactions with the MS. In the first part of this work the Pd-based alloys and layered structures have been studied as promising electro-catalysts for the ORR on the fuel cell cathodes, more precisely Pd-Co alloys and Pd/M/Pd (M=Co,Fe). There exists a robust model linking the activity of a surface toward ORR to computable thermodynamic properties of the system and further to the binding energies of the ORR intermediates on the catalyst surface. A more challenging task is to find how to tune these binding energies through modification of the surface electronic structure that can be achieved by varying the surface composition and/or morphology. To resolve this challenge, the electronic structure, binding energies of intermediates and the ORR free energies have been calculated within the density functional theory (DFT) approximation. The results presented in this work show that in contrast to the widely accepted notion, the strain exerted by a substrate on AE hardly affects the surface activity toward ORR, while the hybridization of the electronic states of the AE-and MS-electronic states is the key factor controlling the catalytic properties of these systems. Next it is shown that the catalytic activity of the promising anode electrocatalysts, such as Pt/M, M=Au, Ru and Pd, is also determined by the AE-MS hybridization with a minor effect of the strain. Furthermore, we have shown that, if AE is weakly bound to the substrate (as it is for Pt/Au), surface reconstruction occurs. This leads to the breaking of the relation between the electronic structure of the clean surface and the reactivity of the sytem. Other kind of promising ORR catalysts is designed in the form of Ru nanoparticles modified by chalcogens. In this work, I present the results obtained for small Ru clusters and flat Ru facets modified with chalcogens (S, Se and Te). The O and OH binding energies are chosen as descriptors of the ORR. The results on the two systems are compared, concluding that large clusters with relative large flat facets have higher catalytic activity due to the absence of low coordinated and thus high reactive Ru atoms. Regarding the problem of the hydrogen production via photo-catalytic splitting of water, one of the challenges is tuning the band gap of the photo-anodes to optimal levels. Graphitic carbon nitride (g-C3N4) is a promising material to be used as a photo-anode, however, a reduction of the band gap width by rational doping of the material would improve the efficiency significantly. This issue is addressed in the last chapter of this work. Two problems are considered: a) the stability of the doped system and b) the band gap width. To address the first problem the ab-initio thermodynamics approach has been used, finding that the substitution of C and N with the doping agent (B, C, N, O, Si and P) is thermodynamically preferred over the interstitial addition of dopant to the g-C3N4 structure. However, due to high kinetic energy barriers for the detachment of C and N atoms, involved in the substitution doping, the interstitial addition found to be kinetically more favorable. Since the density functional theory fails to reproduce the band gap of semiconductors correctly, the GW approximation was used to study the band gap of the system. The results indicate that the g-C3N4 system maintain its semiconductor character if doped with B, O and P under certain conditions, while reducing the band gap.
Show less - Date Issued
- 2013
- Identifier
- CFE0005288, ucf:50546
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005288
- Title
- Study of Polychlorinated Biphenyl Dechlorination by Zero Valent Magnesium With and Without Activated Carbon in Acidified Ethanol-Ethyl Lactate System.
- Creator
-
Zullo, Fiona, Yestrebsky, Cherie, Clausen, Christian, Campiglia, Andres, Zou, Shengli, Duranceau, Steven, University of Central Florida
- Abstract / Description
-
Polychlorinated biphenyls (PCBs) are synthetic organic chemicals that ca de detected in the environment worldwide. PCBs were banned in the U.S in 1979 owing to their toxicity and persistence in the environment. Today PCBs are classified as human carcinogens and are among the top ten of the U.S Environmental Protection Agency's (EPA) most toxic chemicals. Many researchers have shown soil to be contaminated with PCBs at concentrations as high as 750 ppm. Given the toxicity of PCBs, there is an...
Show morePolychlorinated biphenyls (PCBs) are synthetic organic chemicals that ca de detected in the environment worldwide. PCBs were banned in the U.S in 1979 owing to their toxicity and persistence in the environment. Today PCBs are classified as human carcinogens and are among the top ten of the U.S Environmental Protection Agency's (EPA) most toxic chemicals. Many researchers have shown soil to be contaminated with PCBs at concentrations as high as 750 ppm. Given the toxicity of PCBs, there is an urgent need to extract and degrade such chemicals from contaminated soil in a cost effective way. Prior work revealed a novel method of degradation of PCBs via hydrodehalogenation with zero-valent magnesium in acidified ethanol and ethyl lactate as a solvent system. Even though this degradation method gave satisfactory results for PCB degradation, this system cannot tolerate more than 3% water in order to degrade PCBs, limiting its application to wet soil field samples. In the present work a new system of acidified ethanol and ethyl lactate with ZVMg over activated carbon was developed which shows promising results on the degradation process of PCBs even with water present in the system. A detailed study of the byproducts formed in the dechlorination process and a degradation pathway, along with the activity of the system over time, are presented in this research.Also, a study of the mechanism involved in this reaction was done via computational methods to elucidate a mechanism pathway. It was demonstrated that these reactions are exothermic and involved two transition states, the formation of the first transition state being the limiting step of this reaction.The torsion angle of the PCB congeners was also shown to be an extremely important factor in order to be able to use activated carbon as part of the remediation process. These findings allow a greater understanding of the reductive dechlorination assisted by ZVMg and will help to improve the remediation process in field samples.
Show less - Date Issued
- 2016
- Identifier
- CFE0006205, ucf:51105
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006205
- Title
- THE EFFECTS OF A STRUCTURED LIFESTYLE INTERVENTION PROGRAM IN CONJUNCTION WITH DIETARY SUPPLEMENTATION ON WEIGHT LOSS AND RISK FACTORS FOR THE METABOLIC SYNDROME.
- Creator
-
Zukley, Linda, Angelopoulos, Theodore, University of Central Florida
- Abstract / Description
-
The objective of this study was to determine the effects of a structured weight loss program that included hypocaloric diet, exercise and dietary supplementation, on weight loss, metabolic syndrome risk factors and antioxidant levels in healthy overweight and obese females. Thirty-seven healthy overweight and obese women (BMI 29.5 ± 2.3 kg/m2, 41.1 ± 7.1 yrs) participated in this study. The subjects were randomized into one of two groups: an exercise, hypocaloric diet and antioxidant...
Show moreThe objective of this study was to determine the effects of a structured weight loss program that included hypocaloric diet, exercise and dietary supplementation, on weight loss, metabolic syndrome risk factors and antioxidant levels in healthy overweight and obese females. Thirty-seven healthy overweight and obese women (BMI 29.5 ± 2.3 kg/m2, 41.1 ± 7.1 yrs) participated in this study. The subjects were randomized into one of two groups: an exercise, hypocaloric diet and antioxidant supplement (LifePak®; LSANT group, n=20) or an exercise, hypocaloric diet and appetite suppression supplement (HTP Complex® and TēGreen®; LSAS group, n=17). A significant weight loss occurred in both groups after 12 weeks (LSANT: -2.8 ± 2.8 kg and LSAS: -4.3 ± 2.7 kg, p<0.001). Body fat mass, percent body fat, and waist circumference significantly improved in both groups (p<0.05). No significant difference was found between the groups for weight loss (p>0.05). However, a significant difference was found between the groups for body fat mass (LSANT: -1.8 ± 2.6 kg; LSAS: -3.4 ± 2.4 kg, p ≤ 0.05). Glucose, insulin and insulin resistance (HOMA-IR) were significantly decreased in the LSAS group (glucose: -5.0 ± 6.8 mg/dl, p=0.008; insulin: -2.6 ± 3.8 uIU/dl, p=0.013; and HOMA-IR: -0.7 ± 1.0, p=0.012) but not in the LSANT group (p>0.05). There were no significant differences (p>0.05) observed within or between the groups for cholesterol, triglycerides or LDL-c. HDL-c decreased significantly in the LSANT group (-2.9 ± 5.3 mg/dl, p=0.024) but not in the LSAS group (p>0.05). Skin carotenoid scores (SCS) increased significantly within the LSANT group (LSANT: 10950 ± 8395 SCS, p<0.001) but not the LSAS group (p>0.05). Lifestyle intervention that involves a structured hypocaloric diet and increased physical activity results in weight loss and improvements in body composition. However, supplementation with an appetite suppressant (HTP Complex®) did not enhance weight loss beyond what was achieved with a structured lifestyle intervention. Antioxidant supplementation may be of benefit during a weight loss program that incorporates physical activity and a low energy diet.
Show less - Date Issued
- 2007
- Identifier
- CFE0001815, ucf:47348
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001815
- Title
- Elementary Reading Coaches in Florida: A Study of their Background, Experiences, Coaching Activities, Time, and Other Factors Related to Reading Achievement.
- Creator
-
Zugelder, Gina, Wegmann, Susan, Taylor, Rosemarye, Roberts, Sherron, Clements, Taylar, Puig, Enrique, University of Central Florida
- Abstract / Description
-
The focus of this research was to investigate and clarify the daily work lives of elementary reading coaches in central Florida by studying their background, academic and professional experiences. The beliefs and perceptions of the reading coaches on factors that influence reading achievement were examined. The responses from 96 participating elementary reading coaches were used to investigate (a) the relationship between demographic information, professional experiences, and academic...
Show moreThe focus of this research was to investigate and clarify the daily work lives of elementary reading coaches in central Florida by studying their background, academic and professional experiences. The beliefs and perceptions of the reading coaches on factors that influence reading achievement were examined. The responses from 96 participating elementary reading coaches were used to investigate (a) the relationship between demographic information, professional experiences, and academic background of the reading coach, (b) the percentage of time reading coaches engaged in specific coaching activities, and (c) the linkage between coaching activities and change in the Florida Comprehensive Assessment Test developmental scale scores. Data from a web-based survey and personal interviews were used to collect pertinent data to understand the daily work lives of the elementary reading coaches and bring awareness to perceptions, successes and hindrances to the role and the impact on reading achievement. Descriptive statistics were used to present demographic, professional and academic information about the reading coaches. Multiple regression analyses were performed using time allocated to coaching activities and the change in reading achievement to determine existing relationships. Developmental scale score change was examined from the baseline year to the third year. Qualitative analyses were used to determine reading coach themes from the survey responses. Participant profiles, calling on the tenets of case study methodology, were developed based on the triangulated data. Narrative descriptions of coaching data for the participant profiles were organized by years of teaching experience of the reading coach. The results of the study indicated that reading coaches perceived coach-teacher collaboration to be the most influential activity affecting reading achievement. This perception was not congruent with finding of time spent and change on reading achievement. Recommendations were presented including a formalized understanding of the daily work lives of reading coaches by school districts, administrators and the reading coaches themselves.
Show less - Date Issued
- 2012
- Identifier
- CFE0004286, ucf:49530
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004286
- Title
- FATAL CRASHES CAUSED BY LIGHT TRUCKS RELATIVE TO CARS: A TEST OF THE OFFSETTING BEHAVIOR HYPOTHESIS.
- Creator
-
Zubritsky, Adam, Caputo, Michael, University of Central Florida
- Abstract / Description
-
This thesis presents an econometric test of the offsetting behavior hypothesis concerning drivers of light trucks relative to cars. The main objective is to determine whether drivers of light trucks offset perceived safety benefits associated with larger vehicles by driving more aggressively than drivers of cars, subsequently causing more fatal crashes, holding all else constant. An empirical model using data on pedestrian fatalities across the United States over a five-year period is...
Show moreThis thesis presents an econometric test of the offsetting behavior hypothesis concerning drivers of light trucks relative to cars. The main objective is to determine whether drivers of light trucks offset perceived safety benefits associated with larger vehicles by driving more aggressively than drivers of cars, subsequently causing more fatal crashes, holding all else constant. An empirical model using data on pedestrian fatalities across the United States over a five-year period is developed and analyzed in order to capture the desired results. Estimates provide substantial evidence in support of the offsetting behavior hypothesis. To strengthen the case for driver offsetting behavior beyond previous studies, the model is estimated again using pedalcyclist fatalities. The results also point to interesting conclusions regarding the effects of increased speed limits on the behavior of drivers.
Show less - Date Issued
- 2005
- Identifier
- CFE0000579, ucf:46469
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000579
- Title
- IS MIGRANT INTEGRATION POLICY CONVERGING IN EUROPE? A COMPARISON OF EU-12 AND EU-15 STATES.
- Creator
-
Zuardo, Steven, Mirilovic, Nikola, University of Central Florida
- Abstract / Description
-
Immigration issues have dominated the political discourse of liberal democracies around the world in the 21st century. Recent elections in the United States and the Netherlands focused extensively on migrant flows, illegal immigration and migrant integration. Upcoming elections in France seem to be operating within similar parameters. These occurrences underpin a larger critique about the perceived failure of liberal democratic institutions to contend with immigration trends and successfully...
Show moreImmigration issues have dominated the political discourse of liberal democracies around the world in the 21st century. Recent elections in the United States and the Netherlands focused extensively on migrant flows, illegal immigration and migrant integration. Upcoming elections in France seem to be operating within similar parameters. These occurrences underpin a larger critique about the perceived failure of liberal democratic institutions to contend with immigration trends and successfully integrate migrants within their societies. Nowhere has this critique been more prevalent than within the public and political discourse of the European Union, the institution of focus for this paper. As the EU member states struggle to cope with their migrant issues, scholars are increasingly looking to the larger EU governmental structure to anticipate how the region will handle these challenges. Accordingly, much of the scholarly work done on subjects such as integration policy within the EU are mainly focused upon the perceived convergence of policy amongst member states. The intent of this thesis therefore, is to evaluate the validity of claims that migrant integration policy is converging amongst EU member states, and to explain why this may be the case. This was accomplished via a cross-comparison of policy outcome scores, (provided by the Migration Integration Policy Index), over time between EU-15 and EU-12 states. The convergence of policy in the EU is a topic that has been routinely addressed by scholars, but by examining the potential trends amongst the traditionally ignored EU-12 states, this thesis hopes to contribute to the academic discourse by providing a different perspective.
Show less - Date Issued
- 2017
- Identifier
- CFH2000215, ucf:45938
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000215
- Title
- CHARACTERIZATION OF POLYETHERIMIDE UNDER STATIC, DYNAMIC, AND MULTIPLE IMPACT CONDITIONS.
- Creator
-
Zuanetti, Bryan, Gordon, Ali, University of Central Florida
- Abstract / Description
-
The application of polymers in robust engineering designs is on the rise due to their excellent mechanical properties such as high fracture toughness, specific strength, durability, as well as, thermal and chemical resistances. Implementation of some advanced polymeric solids is limited due to the lack of available mechanical properties. In order for these materials to endure strenuous engineering designs it is vital to investigate their response in multiple loading rates and conditions. In...
Show moreThe application of polymers in robust engineering designs is on the rise due to their excellent mechanical properties such as high fracture toughness, specific strength, durability, as well as, thermal and chemical resistances. Implementation of some advanced polymeric solids is limited due to the lack of available mechanical properties. In order for these materials to endure strenuous engineering designs it is vital to investigate their response in multiple loading rates and conditions. In this thesis, the mechanical response of polyethermide (PEI) is characterized under quasi-static, high strain rate, and multiple impact conditions. Standard tension, torsion, and compression experiments are performed in order to distinguish the multi-regime response of PEI. The effects of physical ageing and rejuvenation on the quasi-static mechanical response are investigated. The strain softening regime resulting from strain localization is eliminated by thermal and mechanical rejuvenation, and the advantages of these processes are discussed. The dynamic fracture toughness of the material in response to notched impact via Charpy impact test is evaluated. The high strain-rate response of PEI to uniaxial compression is evaluated at rates exceeding 104/s via miniaturized Split Hopkinson Pressure Bar (MSHPB), and compared to the quasi-static case to determine strain-rate sensitivity. The elastic response of the aged material to multiple loading conditions are correlated using the Ramberg-Osgood equation, while the elastoplastic response of rejuvenated PEI is correlated using a both the Ramberg-Osgood equation and a novel model. The strain-rate sensitivity of the strength is found to be nominally bilinear and transition strains are modeled using the Ree-Erying formulation. Finally, multiple impact experiments are performed on PEI using the MSHPB and a model is proposed to quantify damage as a result of collision.
Show less - Date Issued
- 2013
- Identifier
- CFH0004531, ucf:45166
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004531
- Title
- TOWARDS DIRECT WRITING OF 3-D PHOTONIC CIRCUITS USING ULTRAFAST LASERS.
- Creator
-
Zoubir, Arnaud, Richardson, Martin, University of Central Florida
- Abstract / Description
-
The advent of ultrafast lasers has enabled micromachining schemes that cannot be achieved by other current techniques. Laser direct writing has emerged as one of the possible routes for fabrication of optical waveguides in transparent materials. In this thesis, the advantages and limitations of this technique are explored. Two extended-cavity ultrafast lasers were built and characterized as the laser sources for this study, with improved performance over existing systems. Waveguides are...
Show moreThe advent of ultrafast lasers has enabled micromachining schemes that cannot be achieved by other current techniques. Laser direct writing has emerged as one of the possible routes for fabrication of optical waveguides in transparent materials. In this thesis, the advantages and limitations of this technique are explored. Two extended-cavity ultrafast lasers were built and characterized as the laser sources for this study, with improved performance over existing systems. Waveguides are fabricated in oxide glass, chalcogenide glass, and polymers, these being the three major classes of materials for the telecommunication industry. Standard waveguide metrology is performed on the fabricated waveguides, including refractive index profiling and mode analysis. Furthermore, a finite-difference beam propagation method for wave propagation in 3D-waveguides is proposed. The photo-structural modifications underlying the changes in the material optical properties after exposure are investigated. The highly nonlinear processes of the light/matter interaction during the writing process are described using a free electron model. UV/visible absorption spectroscopy, photoluminescence spectroscopy and Raman spectroscopy are used to assess the changes occurring at the atomic level. Finally, the impact of laser direct writing on nonlinear waveguide applications is discussed.
Show less - Date Issued
- 2004
- Identifier
- CFE0000236, ucf:46252
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000236
- Title
- OPTIMIZATION OF ZONAL WAVEFRONT ESTIMATION AND CURVATURE MEASUREMENTS.
- Creator
-
Zou, Weiyao, Rolland, Jannick, University of Central Florida
- Abstract / Description
-
Optical testing in adverse environments, ophthalmology and applications where characterization by curvature is leveraged all have a common goal: accurately estimate wavefront shape. This dissertation investigates wavefront sensing techniques as applied to optical testing based on gradient and curvature measurements. Wavefront sensing involves the ability to accurately estimate shape over any aperture geometry, which requires establishing a sampling grid and estimation scheme, quantifying...
Show moreOptical testing in adverse environments, ophthalmology and applications where characterization by curvature is leveraged all have a common goal: accurately estimate wavefront shape. This dissertation investigates wavefront sensing techniques as applied to optical testing based on gradient and curvature measurements. Wavefront sensing involves the ability to accurately estimate shape over any aperture geometry, which requires establishing a sampling grid and estimation scheme, quantifying estimation errors caused by measurement noise propagation, and designing an instrument with sufficient accuracy and sensitivity for the application. Starting with gradient-based wavefront sensing, a zonal least-squares wavefront estimation algorithm for any irregular pupil shape and size is presented, for which the normal matrix equation sets share a pre-defined matrix. A GerchbergSaxton iterative method is employed to reduce the deviation errors in the estimated wavefront caused by the pre-defined matrix across discontinuous boundary. The results show that the RMS deviation error of the estimated wavefront from the original wavefront can be less than λ/130~ λ/150 (for λ equals 632.8nm) after about twelve iterations and less than λ/100 after as few as four iterations. The presented approach to handling irregular pupil shapes applies equally well to wavefront estimation from curvature data. A defining characteristic for a wavefront estimation algorithm is its error propagation behavior. The error propagation coefficient can be formulated as a function of the eigenvalues of the wavefront estimation-related matrices, and such functions are established for each of the basic estimation geometries (i.e. Fried, Hudgin and Southwell) with a serial numbering scheme, where a square sampling grid array is sequentially indexed row by row. The results show that with the wavefront piston-value fixed, the odd-number grid sizes yield lower error propagation than the even-number grid sizes for all geometries. The Fried geometry either allows sub-sized wavefront estimations within the testing domain or yields a two-rank deficient estimation matrix over the full aperture; but the latter usually suffers from high error propagation and the waffle mode problem. Hudgin geometry offers an error propagator between those of the Southwell and the Fried geometries. For both wavefront gradient-based and wavefront difference-based estimations, the Southwell geometry is shown to offer the lowest error propagation with the minimum-norm least-squares solution. Noll's theoretical result, which was extensively used as a reference in the previous literature for error propagation estimate, corresponds to the Southwell geometry with an odd-number grid size. For curvature-based wavefront sensing, a concept for a differential Shack-Hartmann (DSH) curvature sensor is proposed. This curvature sensor is derived from the basic Shack-Hartmann sensor with the collimated beam split into three output channels, along each of which a lenslet array is located. Three Hartmann grid arrays are generated by three lenslet arrays. Two of the lenslets shear in two perpendicular directions relative to the third one. By quantitatively comparing the Shack-Hartmann grid coordinates of the three channels, the differentials of the wavefront slope at each Shack-Hartmann grid point can be obtained, so the Laplacian curvatures and twist terms will be available. The acquisition of the twist terms using a Hartmann-based sensor allows us to uniquely determine the principal curvatures and directions more accurately than prior methods. Measurement of local curvatures as opposed to slopes is unique because curvature is intrinsic to the wavefront under test, and it is an absolute as opposed to a relative measurement. A zonal least-squares-based wavefront estimation algorithm was developed to estimate the wavefront shape from the Laplacian curvature data, and validated. An implementation of the DSH curvature sensor is proposed and an experimental system for this implementation was initiated. The DSH curvature sensor shares the important features of both the Shack-Hartmann slope sensor and Roddier's curvature sensor. It is a two-dimensional parallel curvature sensor. Because it is a curvature sensor, it provides absolute measurements which are thus insensitive to vibrations, tip/tilts, and whole body movements. Because it is a two-dimensional sensor, it does not suffer from other sources of errors, such as scanning noise. Combined with sufficient sampling and a zonal wavefront estimation algorithm, both low and mid frequencies of the wavefront may be recovered. Notice that the DSH curvature sensor operates at the pupil of the system under test, therefore the difficulty associated with operation close to the caustic zone is avoided. Finally, the DSH-curvature-sensor-based wavefront estimation does not suffer from the 2-ambiguity problem, so potentially both small and large aberrations may be measured.
Show less - Date Issued
- 2007
- Identifier
- CFE0001566, ucf:47145
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001566
- Title
- AN EXAMINATION OF THE FRAUDULENT FACTORS ASSOCIATED WITH CORPORATE FRAUD.
- Creator
-
Zmuda, Ronald, Desai, Naman, University of Central Florida
- Abstract / Description
-
Between the years 1998 and 2002, the United States suffered a time in which several large companies engaged in fraudulent behavior which eroded investor confidence in the stock market and to some extent destabilized the economy. Audits, which were conducted to assess the validity and reliability of a company's financial statements, were not detecting the material misstatements in the statements. As a result, both the US Government and the accounting profession needed to come up with a way to...
Show moreBetween the years 1998 and 2002, the United States suffered a time in which several large companies engaged in fraudulent behavior which eroded investor confidence in the stock market and to some extent destabilized the economy. Audits, which were conducted to assess the validity and reliability of a company's financial statements, were not detecting the material misstatements in the statements. As a result, both the US Government and the accounting profession needed to come up with a way to prevent these immense frauds from occurring in the future. As a response to these large frauds, in 2002, the US Government passed the Sarbanes - Oxley Act of 2002 (SOX) and the American Institute of Certified Public Accountants (AICPA) issued Statement on Auditing Standards No. 99(SAS No. 99) to improve investor confidence and the auditing function's ability to detect material frauds. The intent of this thesis was to look at the fraudulent factors associated with several recent corporate frauds and compare them to the standards set by SAS No. 99. Through the analysis conducted, this thesis looks at the relationships between pressures, opportunities, and rationalizations made during the act of fraud.
Show less - Date Issued
- 2011
- Identifier
- CFH0004084, ucf:44782
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004084
- Title
- INTEGRATING JOURNAL WRITING WITH INQUIRY BASED SCIENCE INSTRUCTION IN A SECOND GRADE CLASSROOM.
- Creator
-
Zissman, Lauren, Lewis, Nancy, University of Central Florida
- Abstract / Description
-
This action research study investigated the effects of using science journals to promote science writing and to investigate changes in student attitudes in a second grade inquiry-based science class. This was an action research study in which qualitative and quantitative data was collected. The data was collected using science journals, pre and post inventories, field notes, teacher observations, videotaped science inquiry lessons, and surveys. The students demonstrated a true fondness for...
Show moreThis action research study investigated the effects of using science journals to promote science writing and to investigate changes in student attitudes in a second grade inquiry-based science class. This was an action research study in which qualitative and quantitative data was collected. The data was collected using science journals, pre and post inventories, field notes, teacher observations, videotaped science inquiry lessons, and surveys. The students demonstrated a true fondness for journal writing and expressed interest in continued use. After concluding this action research study, I better understand the benefits of utilizing journal writing to enhance my teaching of the science curriculum as well as the other disciplines I facilitate.
Show less - Date Issued
- 2005
- Identifier
- CFE0000437, ucf:46383
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000437
- Title
- METHANE AND DIMETHYL ETHER OXIDATION AT ELEVATED TEMPERATURES AND PRESSURE.
- Creator
-
Zinner, Christopher, Basu, Saptarshi, University of Central Florida
- Abstract / Description
-
Autoignition and oxidation of two Methane (CH4) and Dimethyl Ether (CH3OCH3 or DME) mixtures in air were studied in shock tubes over a wide range of equivalence ratios at elevated temperatures and pressures. These experiments were conducted in the reflected shock region with pressures ranging from 0.8 to 35.7 atmospheres, temperatures ranging from 913 to 1650 K, and equivalence ratios of 2.0, 1.0, 0.5, and 0.3. Ignition delay times were obtained from shock-tube endwall pressure traces for...
Show moreAutoignition and oxidation of two Methane (CH4) and Dimethyl Ether (CH3OCH3 or DME) mixtures in air were studied in shock tubes over a wide range of equivalence ratios at elevated temperatures and pressures. These experiments were conducted in the reflected shock region with pressures ranging from 0.8 to 35.7 atmospheres, temperatures ranging from 913 to 1650 K, and equivalence ratios of 2.0, 1.0, 0.5, and 0.3. Ignition delay times were obtained from shock-tube endwall pressure traces for fuel mixtures of CH4/CH3OCH3 in ratios of 80/20 percent volume and 60/40 percent volume, respectively. Close examination of the data revealed that energy release from the mixture is occurring in the time between the arrival of the incident shock wave and the ignition event. An adjustment scheme for temperature and pressure was devised to account for this energy release and its effect on the ignition of the mixture. Two separate ignition delay correlations were developed for these pressure- and temperature-adjusted data. These correlations estimate ignition delay from known temperature, pressure, and species mole fractions of methane, dimethyl ether, and air (0.21 O2 + 0.79 N2). The first correlation was developed for ignition delay occurring at temperatures greater than or equal to 1175 K and pressures ranging from 0.8 to 35.3 atm. The second correlation was developed for ignition delay occurring at temperatures less than or equal to 1175 K and pressures ranging from 18.5 to 40.0 atm. Overall good agreement was found to exist between the two correlations and the data of these experiments. Findings of these experiments also include that with pressures at or below ten atm, increased concentrations of dimethyl ether will consistently produce faster ignition times. At pressures greater than ten atmospheres it is possible for fuel rich mixtures with lower concentrations of dimethyl ether to give the fastest ignition times. This work represents the most thorough shock tube investigation for oxidation of methane with high concentration levels of dimethyl ether at gas turbine engine relevant temperatures and pressures. The findings of this study should serve as a validation for detailed chemical kinetics mechanisms.
Show less - Date Issued
- 2008
- Identifier
- CFE0002096, ucf:47539
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002096