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Title: BARRIERS AFFECTING COMPLIANCE WITH THE IMPLEMENTATION OF EARLY GOAL DIRECTED THERAPY IN THE EMERGENCY DEPARTMENT.
Creator: Castro, Ivan, Blackwell, Christopher, University of Central Florida
Abstract / Description: Early Goal Directed Therapy (EGDT) has been thoroughly researched and clinically supported to be effective at lowering morbidity and mortality associated with severe sepsis and septic shock. Due to the strengths of its efficacy, it has been integrated as an essential component of the Surviving Sepsis Campaign. However, very few studies have explored the barriers that affect compliance of the protocol in actual practice. The purpose of this study was to synthesize current research findings...
Show moreEarly Goal Directed Therapy (EGDT) has been thoroughly researched and clinically supported to be effective at lowering morbidity and mortality associated with severe sepsis and septic shock. Due to the strengths of its efficacy, it has been integrated as an essential component of the Surviving Sepsis Campaign. However, very few studies have explored the barriers that affect compliance of the protocol in actual practice. The purpose of this study was to synthesize current research findings regarding nursing barriers associated with EGDT. This research was limited to studies performed in the United States between 2003-2012, with patients at least 18 years old, and with data obtained from studies conducted within emergency departments (EDs) only. These findings may serve to help increase the compliance rate with the protocol among nurses in the ED. Findings indicated that compliance rates were mostly affected by two major barriers: 1) Lack of knowledge regarding the presentation and management of sepsis and septic shock, and 2)Lack of resources in the ED to perform the protocol to its full potential. Limitations of the review noted were that most research studies used were in major academic hospitals which limited the generalizability of the findings to other hospital settings. Nursing education should emphasize early recognition and aggressive treatment of sepsis. Future research should focus on addressing the most efficient ways to educate nurses on sepsis presentation and management and the ways these can be implemented in practice.
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Date Issued: 2013
Identifier: CFH0004420, ucf:45095
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004420

Title: EDUCATION FOR PEDIATRIC ONCOLOGY NURSES ON FERTILITY PRESERVATION OF PEDIATRIC ONCOLOGY PATIENTS.
Creator: Breit, Elyse, Loerzel, Victoria, University of Central Florida
Abstract / Description: Although the survival rate of childhood cancer is high, nearly two thirds of these survivors experience negative long-term secondary side effects from cancer treatments. Infertility is one such side effect that can have a prominent impact on quality of life as the patient ages. It is important for nurses working with pediatric oncology patients to provide the patient and family with education about risk for infertility and fertility preservation (FP) in order to allow families to make...
Show moreAlthough the survival rate of childhood cancer is high, nearly two thirds of these survivors experience negative long-term secondary side effects from cancer treatments. Infertility is one such side effect that can have a prominent impact on quality of life as the patient ages. It is important for nurses working with pediatric oncology patients to provide the patient and family with education about risk for infertility and fertility preservation (FP) in order to allow families to make decisions about FP before cancer treatment starts. However, pediatric oncology nurses report being uneducated about FP guidelines and are hesitant to broach this subject with families. The purpose of this HIM thesis is to review nurse perceived barriers related to educating patients and their families about the risk for infertility following cancer treatments and FP and to make recommendations for improving communication between nurses and families about FP. A search was performed using CINAHL, PreCINAHL, PsychINFO, PsychARTICLES, and Medline databases and examined peer-reviewed quantitative and qualitative research studies. Key terms used in the database searches were ped* OR child*, onco* OR cancer*, fert*, and nurs*. Findings indicated that there were many barriers for pediatric oncology nurses, which inhibited the discussion of FP with patients and families such as lack of knowledge and resources, provider attitudes toward FP, and patient factors. Based on the findings, the researcher identified several interventions to aid pediatric oncology nurses in overcoming these barriers to FP discussion.
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Date Issued: 2014
Identifier: CFH0004620, ucf:45295
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004620

Title: INTERFACIAL BEHAVIOR IN POLYMER DERIVED CERAMICS AND SALT WATER PURIFICATION VIA 2D MOS2.
Creator: Li, Hao, An, Linan, Jung, YeonWoong, Zhai, Lei, Feng, Xiaofeng, Yu, Xiaoming, University of Central Florida
Abstract / Description: In the present dissertation, the behavior of the internal potential barrier in a polymer-derived amorphous SiAlCN ceramic was studied by measuring its complex impedance spectra at various dc bias as well as different testing and annealing temperatures. The complex impedancespectra of the polymer-derived a-SiAlCN were measured under various dc bias voltages in a temperature range between 50 and 150?(&)deg;C, as well as different annealing temperatures (1100-1400 (&)deg;C). All spectra,...
Show moreIn the present dissertation, the behavior of the internal potential barrier in a polymer-derived amorphous SiAlCN ceramic was studied by measuring its complex impedance spectra at various dc bias as well as different testing and annealing temperatures. The complex impedancespectra of the polymer-derived a-SiAlCN were measured under various dc bias voltages in a temperature range between 50 and 150?(&)deg;C, as well as different annealing temperatures (1100-1400 (&)deg;C). All spectra, regardless of temperature and bias, consist of two semi-circular arcs,corresponding to the free-carbon phase and the interface, respectively. The impedance of the free-carbon phase is independent of the bias, while that of the interface decreased significantly with increasing dc bias. It is shown that the change of the interfacial capacitance with the bias can be explained using the double Schottky barrier model. The charge-carrier concentration and potential barrier height were estimated by comparing the experimental data and the model.The results revealed that increasing testing temperature led to an increased charge-carrier concentration and a reduced barrier height, both following Arrhenius dependence, whereas the increase in annealing temperature resulted in increased charge-carrier concentration and barrier height. The phenomena were explained in terms of the unique bi-phasic microstructures of the material. The research findings reveal valuable microstructural information of temperaturedependent properties of polymer derived ceramics, and should contribute towards more precise understanding and control of the electrical as well as dielectric properties of polymer derivedceramics. Furthermore, the desalination performances and underlying mechanisms of two-dimensional CVD-grown MoS2 layers membranes have been experimentally assessed. Based on a successful large-area few-layer 2D materials growth, transfer and integration method, the 2D MoS2 layers membranes showed preserved chemical and microstructural integrity after integration. The few-layer 2D MoS2 layers demonstrated superior desalination capability towards various types of seawater salt solutions approaching theoretically-predicted values. Such performances are attributed to the dimensional and geometrical effect, as well as the electrostatic interaction of the inherently-present CVD-induced atomic vacancies for governingboth water permeation and ionic sieving at the solution/2D-layer interfaces.
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Date Issued: 2019
Identifier: CFE0007830, ucf:52813
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007830

Title: Analysis of residual stress and damage mechanisms of thermal barrier coatings deposited via PS-PVD and EB-PVD.
Creator: Rossmann, Linda, Raghavan, Seetha, Sohn, Yongho, Vaidyanathan, Raj, Ghosh, Ranajay, University of Central Florida
Abstract / Description: Thermal barrier coatings (TBCs) are critical to gas turbine engines, as they protect the components in the hot section from the extreme temperatures of operation. The current industry standard method of applying TBCs for turbine blades in jet engines is electron-beam physical vapor deposition (EB-PVD), which results in a columnar structure that is valued for its high degree of strain tolerance. An emerging deposition method is plasma-spray physical vapor deposition (PS-PVD), capable of...
Show moreThermal barrier coatings (TBCs) are critical to gas turbine engines, as they protect the components in the hot section from the extreme temperatures of operation. The current industry standard method of applying TBCs for turbine blades in jet engines is electron-beam physical vapor deposition (EB-PVD), which results in a columnar structure that is valued for its high degree of strain tolerance. An emerging deposition method is plasma-spray physical vapor deposition (PS-PVD), capable of producing a variety of customizable microstructures as well as non-line-of-sight deposition, which allows more complex geometries to be coated, or even multiple parts at once. The pseudo-columnar microstructure that can be produced with PS-PVD is a possible alternative to EB-PVD. However, before PS-PVD can be used to its full potential, its mechanical properties and behavior must be understood. This work contributes to this understanding by characterizing PS-PVD TBCs that have been thermally cycled to simulate multiple lifetimes (0, 300, and 600 thermal cycles). Residual stress in the thermally grown oxide (TGO) layer is characterized by photoluminescence piezospectroscopy as TGO residual stress is correlated with the lifetime of the coating. Residual stress in the top coat is characterized by Raman spectroscopy, because this stress drives cracking in the top coat that can lead to failure. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) are performed to observe microstructural and phase evolution to provide context and possible explanations for the stress results. In addition, EB-PVD samples of the same thermal cycling history are characterized in the same way so that PS-PVD can be benchmarked against the industry standard. The compressive residual stress in the TGO in both coatings was relieved with thermal cycling due to the TGO lengthening as well as microcracking. The PS-PVD samples had slightly lower TGO stress than the EB-PVD, which is attributed to the greater extent of cracking within the TGO, whereas cracking in the EB-PVD samples was at the TGO/topcoat interface. The PS-PVD cycled samples had significant cracking within the topcoat near the TGO due to both greater porosity than EB-PVD samples and regions of unmelted particles that provide little resistance to cracking. The greater convolution of the TGO in the PS-PVD samples results in greater out-of-plane tensile stresses that cause crack initiation, as well as diverts cracks away from the difficult-to-follow interface. The TGO stress results agree with existing literature and extend the thermal cycling beyond what has previously been reported for PS-PVD coatings, revealing a trend of stress relief and stress values similar to that of EB-PVD coatings in this study and in the literature. Residual stress in the topcoat for both coating types became increasingly compressive with thermal cycling, indicating loss of strain tolerance by sintering. The trend of the YSZ stress for both coating types to become more compressive with cycling and with depth agrees with the literature, and the thermal cycling is longer than has been previously reported for PS-PVD. The two coating types had quite different microstructures and crack modes as well as different as-deposited residual stresses, but after thermal cycling had similar stresses in both the TGO and top coat. No samples experienced spallation. These results indicate that, while PS-PVD coatings have different properties and behavior from EB-PVD coatings, they had comparable levels of damage to EB-PVD coatings of the same lifetime and are a viable alternative to EB-PVD. Further tuning of the processing parameters may result in PS-PVD coatings with even more similar behavior to EB-PVD coatings.
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Date Issued: 2019
Identifier: CFE0007717, ucf:52429
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007717

Title: NON-DESTRUCTIVE MICROSTRUCTURAL EVALUATION OF YTTRIA STABILIZED ZIRCONIA, NICKEL ALUMINIDES AND THERMAL BARRIER COATINGS USING ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY.
Creator: Vishweswaraiah, Srinivas, Sohn, Yongho, University of Central Florida
Abstract / Description: There has been an urge for increasing the efficiency in advanced gas turbine engines. To fulfill these needs the inlet gas temperatures should be increased in the gas turbine engines, thermal barrier coatings (TBCs) have gained significant applications in increasing the gas inlet temperatures. Insulating characteristics of ceramic TBCs allow the operation at up to 150~250 ˚C higher gas temperatures. Because of the severe turbine engine operating conditions that include high...
Show moreThere has been an urge for increasing the efficiency in advanced gas turbine engines. To fulfill these needs the inlet gas temperatures should be increased in the gas turbine engines, thermal barrier coatings (TBCs) have gained significant applications in increasing the gas inlet temperatures. Insulating characteristics of ceramic TBCs allow the operation at up to 150~250 ˚C higher gas temperatures. Because of the severe turbine engine operating conditions that include high temperature, steep temperature gradient, thermal cycling, oxidation and hot-corrosion, TBCs can fail by spallation at the interface between the metal and ceramic. The lack of understanding in failure mechanisms and their prediction warrant a development of non-destructive evaluation technique that can monitor the quality and degradation of TBCs. In addition, the development of NDE technique must be based on a robust correlation to the characteristics of TBC failure.The objective of this study is to develop electrochemical impedance spectroscopy (EIS) as a Non-destructive evaluation (NDE) technology for application to TBCs. To have a better understanding of the multilayer TBCs using EIS they were divided into individual layers and EIS were performed on them. The individual layers included polycrystalline ZrO2-7~8 wt.%Y2O3 (YSZ) (topcoat) of two different densities were subjected to sintering by varying the sintering temperature and holding time for three different thickness and hot extruded NiAl alloy buttons which were subjected to isothermal oxidation with varying temperature and time. NiAl is as similar to the available commercial bondcoats used in TBCs. Then degradation monitoring with electrolyte penetration was carried out on electron beam physical vapor deposited (EB-PVD) TBCs as a function of isothermal exposure. Quality control for air plasma sprayed TBCs were carried out as a function of density, thickness and microstructure. Dense vertically cracked TBCs were tested as a function of vertical crack density and thickness.Electrochemical impedance response was acquired from all specimens at room temperature and analyzed with an AC equivalent circuit based on the impedance response as well as multi-layered structure and micro-constituents of specimens. Physical and microstructural features of these specimens were also examined by optical and electron microscopy. The EIS measurement was carried out in a three-electrode system using a standard Flat Cell (K0235) from Princeton Applied Research and IM6e BAS ZAHNER frequency response analyzer. The electrolyte employed in this investigation was 0.01M (molar) potassium Ferri/Ferro Cyanide {(K3Fe(CN)6/K4Fe(CN)6•3H2O)}.The thickness and density were directly related to the resistance and capacitance of the polycrystalline YSZ with varying thickness and open pores. As the effective thickness of the YSZ increased with sintering time and temperature, the resistance of the YSZ (RYSZ) increased proportionally. The variation in capacitance of YSZ (CYSZ) with respect to the change in porosity/density and thickness was clearly detected by EIS. The samples with high porosity (less dense) exhibited large capacitance, CYSZ, compared to those with less porosity (high density), given similar thickness. Cracking in the YSZ monoliths resulted in decrease of resistance and increase in capacitance and this was related to the electrolyte penetration.Growth and spallation of TGO scale on NiAl alloys during isothermal oxidation at various temperatures and holding time was also correlated with resistance and capacitance of the TGO scale. With an increase in the TGO thickness, the resistance of the TGO (RTGO) increased and capacitance of the TGO (CTGO) decreased. This trend in the resistance and capacitance of the TGO changed after prolonged heat treatment. This is because of the spallation of the TGO scale from the metal surface. The parabolic growth of TGO
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Date Issued: 2004
Identifier: CFE0000041, ucf:52855
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000041

Title: AMELIORATION OF AMYLOID BURDEN IN ADVANCED HUMAN AND MOUSE ALZHEIMER'S DISEASE BRAINS BY ORAL DELIVERY OF MYELIN BASIC PROTEIN BIOENCAPSULATED IN PLANT CELLS.
Creator: Kohli, Neha, Daniell, Henry, Kim, Yoon-Seong, Cheng, Zixi, University of Central Florida
Abstract / Description: One of the pathological hallmarks of Alzheimer's disease (AD) is the amyloid plaque deposition in aging brains by aggregation of amyloid-? (A?) peptides. In this study, the effect of chloroplast derived myelin basic protein (MBP) fused with cholera toxin subunit B (CTB) was investigated in advanced diseased stage of human and mouse AD brains. The CTB-fusion protein in chloroplasts facilitates transmucosal delivery in the gut by the natural binding ability of CTB pentameric form with GM1...
Show moreOne of the pathological hallmarks of Alzheimer's disease (AD) is the amyloid plaque deposition in aging brains by aggregation of amyloid-? (A?) peptides. In this study, the effect of chloroplast derived myelin basic protein (MBP) fused with cholera toxin subunit B (CTB) was investigated in advanced diseased stage of human and mouse AD brains. The CTB-fusion protein in chloroplasts facilitates transmucosal delivery in the gut by the natural binding ability of CTB pentameric form with GM1 receptors on the intestinal epithelium. Further, bioencapsulation of the MBP within plant cells confers protection from enzymes and acids in the digestive system. Here, 12-14 months old triple transgenic AD mice were fed with CTB-MBP bioencapsulated in the plant cells for 3 months. A reduction of 67.3% and 33.3% amyloid levels in hippocampal and cortical regions, respectively were observed by immunostaining of brain sections with anti- A? antibody. Similarly, 70% decrease in plaque number and 40% reduction of plaque intensity was observed through thioflavin S (ThS) staining that specifically stains amyloid in the AD brain. Furthermore, ex vivo 3xTg AD mice brain sections showed up to 45% reduction of ThS stained amyloid levels when incubated with enriched CTB-MBP in a concentration dependent manner. Similarly, incubation of enriched CTB-MBP with ex vivo postmortem human brain tissue sections with advanced stage of AD resulted up to 47% decrease of ThS stained amyloid plaque intensity. Lastly, lyophilization of plant material facilitates dehydration and long term storage of capsules at room temperature, in addition to increasing CTB-MBP concentration by 17 fold. These observations offer a low cost solution for treatment of even advanced stages of the AD by facilitating delivery of therapeutic proteins to central nervous system to address other neurodegenerative disease.
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Date Issued: 2012
Identifier: CFE0004564, ucf:49237
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004564

Title: Fatigue Lifetime Approximation based on Quantitative Microstructural Analysis for Air Plasma Sprayed Thermal Barrier Coatings.
Creator: Bargraser, Carmen, Sohn, Yongho, An, Linan, Heinrich, Helge, University of Central Florida
Abstract / Description: The durability of thermal barrier coatings (TBCs) affects the life of the hot section engine components on which they are applied. Fatigue is the general failure mechanism for such components and is responsible for most unexpected failures; therefore it is desirable to develop lifetime approximation models to ensure reliability and durability.In this study, we first examined the microstructural degradation of air plasma sprayed ZrO2-8wt.%Y2O3 TBCs with a low-pressure plasma sprayed CoNiCrAlY...
Show moreThe durability of thermal barrier coatings (TBCs) affects the life of the hot section engine components on which they are applied. Fatigue is the general failure mechanism for such components and is responsible for most unexpected failures; therefore it is desirable to develop lifetime approximation models to ensure reliability and durability.In this study, we first examined the microstructural degradation of air plasma sprayed ZrO2-8wt.%Y2O3 TBCs with a low-pressure plasma sprayed CoNiCrAlY bond coat on an IN 738LC superalloy substrate. The durability of TBCs were assessed through furnace thermal cyclic tests carried out in air at 1100(&)deg;C with a 1-, 10-, and 50-hour dwell period, preceded by a 10-minute heat-up and followed by a 10-minute forced-air-quench. Failure mechanisms of the TBCs were thoroughly investigated through materials characterization techniques including: X-Ray Diffraction, Scanning Electron Microscopy, and Energy Dispersive X-Ray Spectroscopy.Quantitative microstructural analyses were then carried out to document the growth of the thermally grown oxide (TGO) scale, the depletion of the Al-rich ?-NiAl phase in the bond coat, and the population and growth of micro-cracks near the YSZ/bond coat interface. Trends in the TGO growth and the ?-phase depletion in the bond coat followed those of diffusion-controlled processes(-)parabolic growth of the TGO and exponential depletion of the ?-phase. Formation and propagation of cracks within the YSZ resulted in complete spallation of the YSZ topcoat from the bond-coated superalloy substrate.Evolution in these microstructural features was correlated to the lifetime of TBCs, which showed cracking within the YSZ to be the cause of failure; thus a lifetime approximation model was developed, via modification of Paris Law, based on the experimental data. The model predicted the TBC lifetime within 10% of the experimental lifetime.
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Date Issued: 2011
Identifier: CFE0004087, ucf:49145
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004087

Title: AN INVESTIGATION OF COUNSELOR EDUCATORS' ATTITUDES TOWARDS EVIDENCE-BASED PRACTICES AND PERCEIVED BARRIERS TO THE INCORPORATION OF EVIDENCE-BASED PRACTICES IN COUNSELOR EDUCATION CURRICULA.
Creator: Patel, Samir, Hagedorn, Bryce, University of Central Florida
Abstract / Description: The overall purpose of this study was to investigate counselor educatorsÃ‚Â' attitudes towards evidence-based practices (EBPs) and perceived barriers to the inclusion of EBPs in counselor education curricula. Additionally, this study aimed to assess whether counselor educatorsÃ‚Â' level of agreement towards the presence of motivational interviewing (MI) principles in the counseling relationship impacted attitudes towards EBPs. As such, this...
Show moreThe overall purpose of this study was to investigate counselor educatorsÃ‚Â' attitudes towards evidence-based practices (EBPs) and perceived barriers to the inclusion of EBPs in counselor education curricula. Additionally, this study aimed to assess whether counselor educatorsÃ‚Â' level of agreement towards the presence of motivational interviewing (MI) principles in the counseling relationship impacted attitudes towards EBPs. As such, this researcher analyzed four research questions using two instruments and a demographic questionnaire. Two hundred sixty nine counselor educators (39.8% response rate) from the Association of Counselor Education and Supervision responded to an electronic survey, which consisted of the Evidence-Based Practice Attitude Scale (EBPAS; Aarons, 2004), the BARRIERS Scale (Funk, Champagne, Wiese, & Tornquist, 1991), and a demographic questionnaire. Specifically, this study investigated four research questions to determine: (a) the difference in attitude towards adopting EBPs among counselor educators with respect to specific individual factors (i.e. specialized training in evidence-based practices, years of professoriate experience, and primary counselor education focus); (b) the difference in perceived barriers towards adopting EBPs into counselor education curricula among counselor educators with respect to organizational factors (i.e. type of program, status of CACREP accreditation, and faculty position); (c) the influence of EBP attitude on perceived barriers to the inclusion of EBPs in counselor education curricula; and (d) the correlation between counselor educators reported level of agreement towards MI principlesÃ‚Â' presence in the counseling relationship and their attitude towards EBPs. Multivariate analyses of variance (MANOVA) were computed to analyze the data for the first two research questions, while linear regressions were utilized to compute the data for the last two research questions. In terms of individual factors, study results indicated that neither specialized training in EBPs nor years of professoriate experience resulted in significant differences with regards to attitudes towards EBPs. However, data analysis did reveal a significant difference between counselor educators with a clinical focus and counselor educators with a vocational focus. With regards to organizational factors influence on perceived barriers to the inclusion of EBPs in counselor education curricula, analyses revealed that neither CACREP accreditation nor faculty position resulted in any significant differences. Although, analysis did reveal that counselor educators in masters only programs perceived significantly less barriers to the inclusion of EBPs than did counselor educators in doctorate granting programs. Furthermore, results suggested a negative correlation between attitude towards EBPs and barriers towards the inclusion of EBPs in counselor education curricula, and a positive correlation between counselor educatorsÃ‚Â' agreement towards the inclusion of MI principles in the counseling relationship and their attitudes towards EBPs. Limitations of the study, implications for this study, and recommendations for future research as it relates to EBPs in counselor education and the counseling profession are addressed.
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Date Issued: 2010
Identifier: CFE0003063, ucf:48293
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003063

Title: Go with the flow: patterns of connectivity in low dispersal coral reef gobies (Coryphopterus spp.) throughout the western Atlantic.
Creator: Volk, Daniel, Hoffman, Eric, Ferreira, Carlos, Cook, Geoffrey, University of Central Florida
Abstract / Description: Gene flow is an integral biological process that can mediate speciation. While many consider the ocean to be an open environment, there are many barriers that limit gene flow, particularly in the western Atlantic. I analyzed data from two widespread, coral reef fishes, the bridled goby (Coryphopterus glaucofraenum) and sand-canyon goby (C. venezuelae), throughout their range in the western Atlantic. Using two genetic datasets, mitochondrial DNA (mtDNA) and genomic SNPs, I investigated the...
Show moreGene flow is an integral biological process that can mediate speciation. While many consider the ocean to be an open environment, there are many barriers that limit gene flow, particularly in the western Atlantic. I analyzed data from two widespread, coral reef fishes, the bridled goby (Coryphopterus glaucofraenum) and sand-canyon goby (C. venezuelae), throughout their range in the western Atlantic. Using two genetic datasets, mitochondrial DNA (mtDNA) and genomic SNPs, I investigated the evolutionary history of these species and inferred the location and strength of putative barriers. My results suggest that several unique lineages have genetically diverged from one another in the presence of two major barriers. First, the Amazon River has isolated Brazil from the Caribbean and second, a unique lineage was found at an isolated oceanic island, Atol das Rocas, off the northeast coast of Brazil. Furthermore, minor barriers have caused slight genetic differentiation in each of the Caribbean species off the coast of Venezuela, while on the Brazilian coast, there are up to two barriers that separate three genetically unique areas. The stronger of the two barriers is located at Cabo Frio near an upwelling system and the weaker barrier coincides with the outflow of the S(&)#227;o Francisco River. Overall, this research highlights how barriers impact speciation and genetic structure within these gobies in the western Atlantic and more broadly, deepens our understanding about the role of oceanographic features in the speciation process.
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Date Issued: 2017
Identifier: CFE0006924, ucf:51690
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006924

Title: The Integration of Technology Into Instruction by Elementary Teachers In Brevard County, Florida: An Investigative Study.
Creator: Spainhour, Cynthia, Allen, Kay, Gunter, Glenda, Xu, Lihua, University of Central Florida
Abstract / Description: Technology has become a part of the very fabric of society today. Technology's infiltration into business, industries, the medical field, and entertainment has accounted for huge advances. However, in the field of education the impact technology has had is regarded as less impressive. Muller, Wood, Wiloughby, Ross, and Specht (2008) stated (")it is critical to understand teachers' perspectives regarding computer integration in the classrooms(") (p.1523). With the Improving America's Schools...
Show moreTechnology has become a part of the very fabric of society today. Technology's infiltration into business, industries, the medical field, and entertainment has accounted for huge advances. However, in the field of education the impact technology has had is regarded as less impressive. Muller, Wood, Wiloughby, Ross, and Specht (2008) stated (")it is critical to understand teachers' perspectives regarding computer integration in the classrooms(") (p.1523). With the Improving America's Schools Act of 1994 (Public Law 103-382) the integration of technology in schools should be strongly evident. Currently, twenty years after the commitment to develop technologically literate students, technology integration should be well defined, seamless in its usefulness within the learning environment, a part of the very fabric of the educational setting, and consist of a proven track record verifying the positive results for utilization in student learning and achievements. However, a review of the relevant literature revealed the goal has not been achieved and the same issues related to the integration of technology into education are still being discussed, researched, and questioned today as they were in its infancy (Anthony, 2011; Bauer (&) Kenton, 2005; Roschelle, Pea, Hoadley, Gordin, (&) Means, 2000). Allowing teachers to voice what integration meant to them in both practice and definition and the barriers encountered, could shed light on the underutilization of use discovered in literature. New insights provided from teachers could also be utilized by administration and policymakers towards the development of new policies and mandates. Taking a qualitative, investigative approach, two individual and two focus group (n=6, n=8) interviews from four elementary schools in Brevard County were conducted which focused on understanding the practices and experiences of teachers. Results found time, support structures provided by administration, and specific professional development and training's were challenges that hampered successful implementation.
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Date Issued: 2015
Identifier: CFE0006007, ucf:51025
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006007

Title: In-situ synchrotron studies of turbine blade thermal barrier coatings under extreme environments.
Creator: Knipe, Kevin, Raghavan, Seetha, Gordon, Ali, Kapat, Jayanta, Sohn, Yongho, University of Central Florida
Abstract / Description: Thermal Barrier Coatings have been used for decades to impose a thermal gradient between the hot combustion gases and the underlying superalloy substrate in engine turbine blades. Yttria Stabilized Zirconia (YSZ) is an industry standard high temperature ceramic for turbine applications. The protective coating is adhered to the substrate using a nickel based alloy bond coat. Through exposure to high temperature, a Thermally Grown Oxide (TGO) layer develops at the bond coat-YSZ interface. Large...
Show moreThermal Barrier Coatings have been used for decades to impose a thermal gradient between the hot combustion gases and the underlying superalloy substrate in engine turbine blades. Yttria Stabilized Zirconia (YSZ) is an industry standard high temperature ceramic for turbine applications. The protective coating is adhered to the substrate using a nickel based alloy bond coat. Through exposure to high temperature, a Thermally Grown Oxide (TGO) layer develops at the bond coat-YSZ interface. Large residual stresses develop in these layers due to thermal expansion mismatch that occurs during cool down from high temperature spraying and cyclic operating conditions. Despite their standard use, much is to be determined as to how these residual stresses are linked to the various failure modes. This study developed techniques to monitor the strain and stress in these internal layers during thermal gradient and mechanical conditions representing operating conditions. The thermal gradient is applied across the coating thickness of the tubular samples from infrared heating of the outer coating and forced air internal cooling of the substrate. While thermal and mechanical loading conditions are applied, 2-dimensional diffraction measurements are taken using the high-energy Synchrotron X-Rays and analyzed to provide high-resolution depth-resolved strain. This study will include fatigue comparisons through use of samples, which are both 'as-coated' as well as aged to various stages in a TBC lifespan. Studies reveal that variations in thermal gradients and mechanical loads create corresponding trends in depth resolved strains with the largest effects displayed at or near the bond coat/TBC interface. Single cycles as well as experiments targeting thermal gradient and mechanical effects were conducted to capture these trends. Inelastic behavior such as creep was observed and quantified for the different layers at high temperatures. From these studies more accurate lifespan predictions, material behaviors, and causes of failure modes can be determined. The work further develops measurement and analysis techniques for diffraction measurements in internal layers on a coated tubular sample which can be used by various industries to analyze similar geometries with different applications.
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Date Issued: 2014
Identifier: CFE0005640, ucf:50206
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005640

Title: ON THE NATURE OF THE FLOW IN A SEPARATED ANNULAR DIFFUSER.
Creator: Dunn, Jason, Kapat, Jayanta, University of Central Florida
Abstract / Description: The combustor-diffuser system remains one of the most studied sections of the turbomachine. Most of these investigations are due to the fact that quite a bit of flow diffusion is required in this section as the high speed flow exits the compressor and must be slowed down to enter the combustor. Like any diffusion process there is the chance for the development of an unfavorable adverse pressure gradient that can lead to flow separation; a cause of drastic losses within a turbine. There are...
Show moreThe combustor-diffuser system remains one of the most studied sections of the turbomachine. Most of these investigations are due to the fact that quite a bit of flow diffusion is required in this section as the high speed flow exits the compressor and must be slowed down to enter the combustor. Like any diffusion process there is the chance for the development of an unfavorable adverse pressure gradient that can lead to flow separation; a cause of drastic losses within a turbine. There are two diffusion processes in the combustor-diffuser system: The flow first exits the compressor into a pre-diffuser, or compressor discharge diffuser. This diffuser is responsible for a majority of the pressure recovery. The flow then exits the pre-diffuser by a sudden expansion into the dump diffuser. The dump diffuser comprises the majority of the losses, but is necessary to reduce the fluid velocity within acceptable limits for combustion. The topic of active flow control is gaining interest in the industry because such a technique may be able to alleviate some of the requirements of the dump diffuser. If a wider angle pre-diffuser with separation control were used the fluid velocity would be slowed more within that region without significant losses. Experiments were performed on two annular diffusers to characterize the flow separation to create a foundation for future active flow control techniques. Both diffusers had the same fully developed inlet flow condition, however, the expansion of the two diffusers differed such that one diffuser replicated a typical compressor discharge diffuser found in a real machine while the other would create a naturally separated flow along the outer wall. Both diffusers were tested at two Reynolds numbers, 5x104 and 1x105, with and without a vertical wall downstream of the exit to replicate the dump diffuser that re-directs the flow from the pre-diffuser outlet to the combustor. Static pressure measurements were obtained along the OD and ID wall of the diffusers to determine the recovered pressure throughout the diffuser. In addition to these measurements, tufts were used to visualize the flow. A turbulent CFD model was also created to compare against experimental results. In the end, the results were validated against empirical data as well as the CFD model. It was shown that the location of the vertical wall was directly related to the amount of separation as well as the separation characteristics. These findings support previous work and help guide future work for active flow control in a separated annular diffuser both computationally and experimentally.
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Date Issued: 2009
Identifier: CFE0002953, ucf:47944
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002953

Title: The Challenges and Barriers Facing Successful Lean Implementation in the Qatari Manufacturing Organizations.
Creator: Alyousef, Abdulwahab, Elshennawy, Ahmad, Rabelo, Luis, Lee, Gene, University of Central Florida
Abstract / Description: The success of Toyota, the inventor of Lean Systems has drawn the attention of academics, researchers, and executives in the last decades. However, existing lean research is largely focused on developed economies in Europe, the Americas, and in Southeast Asia with little focus on the Arab world in general and Qatar specifically. There has been an emergence of manufacturing organizations and Small and Medium- sized Enterprises (SME) in Qatar recently which was the focus of this research....
Show moreThe success of Toyota, the inventor of Lean Systems has drawn the attention of academics, researchers, and executives in the last decades. However, existing lean research is largely focused on developed economies in Europe, the Americas, and in Southeast Asia with little focus on the Arab world in general and Qatar specifically. There has been an emergence of manufacturing organizations and Small and Medium- sized Enterprises (SME) in Qatar recently which was the focus of this research. Despite the many attempts to implement lean in organizations, there have been a large number of failed attempts. This research aims to study the Qatari Manufacturing Organizations attempts in implementing lean. The main goal of the thesis is to shed a light on the current state of awareness of lean in Qatari Manufacturing Industry and SME and the potential barriers and challenges that prevent the successful adoption of lean. In order to do so, an online survey was designed through the SurveyMonkey tool and organizations were asked to participate.Numerical and statistical results from the survey are discussed along with Pareto charts and two hypothesis tests. The finding indicates that there is no difference between ISO certified and Non-ISO certified organizations in lean implementation. Further, it is understood that most of the manufacturing organizations in Qatar have some level of awareness of lean concepts/tools and practices. The results also show that organizations are not implementing lean concepts and are not using quality management practices effectively. The main obstacle that manufacturing organizations in Qatar face when implementing lean is (")Lack of Employee Engagement(") and (")Unsupportive Organization Culture("). However, it is noted that the research has some limitations such as having most participating organizations in the survey from specific sectors.
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Date Issued: 2019
Identifier: CFE0007778, ucf:52368
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007778

Title: The effect of carbon nanotube/organic semiconductor interfacial area on the performance of organic transistors.
Creator: Kang, Narae, Khondaker, Saiful, Leuenberger, Michael, Zhai, Lei, University of Central Florida
Abstract / Description: Organic field-effect transistors (OFETs) have attracted tremendous attention due to their flexibility, transparency, easy processiblity and low cost of fabrication. High-performance OFETs are required for their potential applications in the organic electronic devices such as flexible display, integrated circuit, and radiofrequency identification tags. One of the major limiting factors in fabricating high-performance OFET is the large interfacial barrier between metal electrodes and OSC which...
Show moreOrganic field-effect transistors (OFETs) have attracted tremendous attention due to their flexibility, transparency, easy processiblity and low cost of fabrication. High-performance OFETs are required for their potential applications in the organic electronic devices such as flexible display, integrated circuit, and radiofrequency identification tags. One of the major limiting factors in fabricating high-performance OFET is the large interfacial barrier between metal electrodes and OSC which results in low charge injection from the metal electrodes to OSC. In order to overcome the challenge of low charge injection, carbon nanotubes (CNTs) have been suggested as a promising electrode material for organic electronic devices. In this dissertation, we study the effect of carbon nanotube (CNT) density in CNT electrodes on the performance of organic field effect transistor (OFETs). The devices were fabricated by thermal evaporation of pentacene on the Pd/single walled CNT (SWCNT) electrodes where SWCNTs of different density (0-30/um) were aligned on Pd using dielectrophoresis (DEP) and cut via oxygen plasma etching to keep the length of nanotube short compared to the channel length. From the electronic transport measurements of 40 devices, we show that the average saturation mobility of the devices increased from 0.02 for zero SWCNT to 0.06, 0.13 and 0.19 cm2/Vs for low (1-5 /(&)#181;m), medium (10-15 /(&)#181;m) and high (25-30 /(&)#181;m) SWCNT density in the electrodes, respectively. The increase is three, six and nine times for low, medium and high density SWCNTs in the electrode compared to the devices that did not contain any SWCNT. In addition, the current on-off ratio and on-current of the devices are increased up to 40 times and 20 times with increasing SWCNT density in the electrodes. Our study shows that although a few nanotubes in the electrode can improve the OFET device performance, significant improvement can be achieved by maximizing SWCNT/OSC interfacial area. The improved OFET performance can be explained due to a reduced barrier height of SWCNT/pentacene interface compared to metal/pentacene interface which provides more efficient charge injection pathways with increased SWCNT/pentacene interfacial area.
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Date Issued: 2012
Identifier: CFE0004558, ucf:49252
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004558

Title: ENVIRONMENTAL DEGRADATION OF OXIDATION RESISTANT AND THERMAL BARRIER COATINGS FOR FUEL-FLEXIBLE GAS TURBINE APPLICATIONS.
Creator: Mohan, Prabhakar, Sohn, Yongho, University of Central Florida
Abstract / Description: The development of thermal barrier coatings (TBCs) has been undoubtedly the most critical advancement in materials technology for modern gas turbine engines. TBCs are widely used in gas turbine engines for both power-generation and propulsion applications. Metallic oxidation-resistant coatings (ORCs) are also widely employed as a stand-alone protective coating or bond coat for TBCs in many high-temperature applications. Among the widely studied durability issues in these high-temperature...
Show moreThe development of thermal barrier coatings (TBCs) has been undoubtedly the most critical advancement in materials technology for modern gas turbine engines. TBCs are widely used in gas turbine engines for both power-generation and propulsion applications. Metallic oxidation-resistant coatings (ORCs) are also widely employed as a stand-alone protective coating or bond coat for TBCs in many high-temperature applications. Among the widely studied durability issues in these high-temperature protective coatings, one critical challenge that received greater attention in recent years is their resistance to high-temperature degradation due to corrosive deposits arising from fuel impurities and CMAS (calcium-magnesium-alumino-silicate) sand deposits from air ingestion. The presence of vanadium, sulfur, phosphorus, sodium and calcium impurities in alternative fuels warrants a clear understanding of high-temperature materials degradation for the development of fuel-flexible gas turbine engines. Degradation due to CMAS is a critical problem for gas turbine components operating in a dust-laden environment. In this study, high-temperature degradation due to aggressive deposits such as V2O5, P2O5, Na2SO4, NaVO3, CaSO4 and a laboratory-synthesized CMAS sand for free-standing air plasma sprayed (APS) yttria stabilized zirconia (YSZ), the topcoat of the TBC system, and APS CoNiCrAlY, the bond coat of the TBC system or a stand-alone ORC, is examined. Phase transformations and microstructural development were examined by using x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. This study demonstrated that the V2O5 melt degrades the APS YSZ through the formation of ZrV2O7 and YVO4 at temperatures below 747Ã‚Â°C and above 747Ã‚Â°C, respectively. Formation of YVO4 leads to the depletion of the Y2O3 stabilizer and the deleterious transformation of the YSZ to the monoclinic ZrO2 phase. The investigation on the YSZ degradation by Na2SO4 and a Na2SO4 + V2O5 mixture (50-50 mol. %) demonstrated that Na2SO4 itself did not degrade the YSZ, however, in the presence of V2O5, Na2SO4 formed vanadates such as NaVO3 that degraded the YSZ through YVO4 formation at temperature as low as 700Ã‚Â°C. The APS YSZ was found to react with the P2O5 melt by forming ZrP2O7 at all temperatures. This interaction led to the depletion of ZrO2 in the YSZ (i.e., enrichment of Y2O3 in tÃ‚Â'-YSZ) and promoted the formation of the fluorite-cubic ZrO2 phase. Above 1250Ã‚Â°C, CMAS deposits were observed to readily infiltrate and significantly dissolve the YSZ coating via thermochemical interactions. Upon cooling, zirconia reprecipitated with a spherical morphology and a composition that depended on the local melt chemistry. The molten CMAS attack destabilized the YSZ through the detrimental phase transformation (tÃ‚Â' -> t -> f + m). Free standing APS CoNiCrAlY was also prone to degradation by corrosive molten deposits. The V2O5 melt degraded the APS CoNiCrAlY through various reactions involving acidic dissolution of the protective oxide scale, which yielded substitutional-solid solution vanadates such as (Co,Ni)3(VO4)2 and (Cr,Al)VO4. The molten P2O5, on the other hand, was found to consume the bond coat constituents significantly via reactions that formed both Ni/Co rich phosphates and Cr/Al rich phosphates. Sulfate deposits such as Na2SO4, when tested in encapsulation, damaged the CoNiCrAlY by Type I acidic fluxing hot corrosion mechanisms at 1000Ã‚Â°C that resulted in accelerated oxidation and sulfidation. The formation of a protective continuous Al2O3 oxide scale by preoxidation treatment significantly delayed the hot corrosion of CoNiCrAlY by sulfates. However, CoNiCrAlY in both as-sprayed and preoxidized condition suffered a significant damage by CaSO4 deposits via a basic fluxing mechanism that yielded CaCrO4 and CaAl2O4. The CMAS melt also dissolved the protective Al2O3 oxide scale developed on CoNiCrAlY by forming anorthite platelets and spinel oxides. Based on the detailed investigation on degradation of the APS YSZ and CoNiCrAlY by various corrosive deposits, an experimental attempt was carried out to mitigate the melt-induced deposit attack. Experimental results from this study demonstrate, for the first time, that an oxide overlay produced by electrophoretic deposition (EPD) can effectively perform as an environmental barrier overlay for APS TBCs. The EPD protective overlay has a uniform and easily-controllable thickness, uniformly distributed closed pores and tailored chemistry. The EPD Al2O3 and MgO overlays were successful in protecting the APS YSZ TBCs against CMAS attack and hot corrosion attack (e.g., sulfate and vanadate), respectively. Furnace thermal cyclic oxidation testing of overlay-modified TBCs on bond-coated superalloy also demonstrated the good adhesive durability of the EPD Al2O3 overlay.
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Date Issued: 2010
Identifier: CFE0003099, ucf:48315
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003099

Title: An Investigation of Boaters' Attitudes toward and Usage of Targeted Mobile Apps.
Creator: Bowerman, Kamra, Delorme, Denise, Brown, Timothy, Neuberger, Lindsay, University of Central Florida
Abstract / Description: The purpose of this study was to understand boaters' adoption and usage of smartphones and mobile apps as well as to obtain their opinion on potential features of a targeted mobile app being developed as part of a broader interdisciplinary Florida Sea Grant outreach project. Data were gathered from an online survey of a sample of 164 boaters from the surrounding Central Florida area. In contrast with previous empirical mobile app studies, many respondents reported using mobile apps for...
Show moreThe purpose of this study was to understand boaters' adoption and usage of smartphones and mobile apps as well as to obtain their opinion on potential features of a targeted mobile app being developed as part of a broader interdisciplinary Florida Sea Grant outreach project. Data were gathered from an online survey of a sample of 164 boaters from the surrounding Central Florida area. In contrast with previous empirical mobile app studies, many respondents reported using mobile apps for information-seeking versus escape gratifications. Further more than half of the respondents' age sixty-five and over indicated using smartphones and mobile apps. These findings reflected recent national trend data showing shifting gratifications and an increase in technology use among older American adults. In regards to the planned mobile app, the study's respondents had favorable reactions to its potential features and indicated an above average intent toward downloading the app.
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Date Issued: 2013
Identifier: CFE0004655, ucf:49902
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004655

$Synchrotron X-Ray Diffraction and Piezospectroscopy used for the Investigation of Individual Mechanical Effects from Environmental Contaminants and Oxide Layer Undulations in Thermal Barrier Coatings$

Title: Synchrotron X-Ray Diffraction and Piezospectroscopy used for the Investigation of Individual Mechanical Effects from Environmental Contaminants and Oxide Layer Undulations in Thermal Barrier Coatings.
Creator: Siddiqui, Sanna, Raghavan, Seetha, Bai, Yuanli, Gordon, Ali, University of Central Florida
Abstract / Description: The durability of Thermal Barrier Coatings (TBCs) used on the turbine blades of aircraft and power generation engines has been known to be affected by sand particle ingression comprised of Calcium-Magnesium-Alumina-Silicate (CMAS). Previous studies have shown that these effects present themselves through variations in the thermomechanical and thermochemical properties of the coating. This study investigated the impact of CMAS ingression on the Yttria Stabilized Zirconia Topcoat (YSZ) and...
Show moreThe durability of Thermal Barrier Coatings (TBCs) used on the turbine blades of aircraft and power generation engines has been known to be affected by sand particle ingression comprised of Calcium-Magnesium-Alumina-Silicate (CMAS). Previous studies have shown that these effects present themselves through variations in the thermomechanical and thermochemical properties of the coating. This study investigated the impact of CMAS ingression on the Yttria Stabilized Zirconia Topcoat (YSZ) and Thermally Grown Oxide (TGO) strain in sprayed Thermal Barrier Coating (TBC) samples of varying porosity with and without CMAS ingression. In-Situ Synchrotron X-ray Diffraction measurements were taken on the sample under thermal loading conditions from which the YSZ and TGO peaks were identified and biaxial strain calculations were determined at high temperature. Quantitative strain results are presented for the YSZ and TGO during a thermal cycle. In-plane strain results for YSZ near the TGO interface for a complete thermal cycle are presented, for a 6% porous superdense sample with CMAS infiltration. The outcomes from this study can be used to understand the role of CMAS on the strain tolerance of the TBC coating.It is well known that under engine operational conditions the development of the TGO layer, with large critical stresses, has been linked to failure of the coating. The growth of the TGO manifests as undulations in a series of peaks and troughs. Understanding the mechanics of the oxide layer at these locations provides significant information with respect to the failure mechanisms of the TBC coating. This study investigated the stress at the peak and trough of a TGO undulation for a cycled Dense Vertically Cracked (DVC) plasma sprayed TBC sample through photo-luminescence (PL) spectroscopy. High resolution nanoscale stress maps were taken nondestructively in the undulation of the TGO. Preliminary results from first line mapping of TGO peak and trough scan, at a resolution of 200 nm, have shown a non-uniform TGO stress variation. The results obtained from this study can be used to understand the stress variation in the peak and trough of a DVC sample's TGO undulation and how it contributes to the life of the TBC coating.
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Date Issued: 2014
Identifier: CFE0005712, ucf:50136
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005712

Title: EVOLUTION OF MICROSTRUCTURE AND RESIDUAL STRESS IN DISC-SHAPE EB-PVD THERMAL BARRIER COATINGS AND TEMPERATURE PROFILE OF HIGH PRESSURE TURBINE BLADE.
Creator: Mukherjee, Sriparna, Sohn, Yongho, University of Central Florida
Abstract / Description: A detailed understanding of failure mechanisms in thermal barrier coatings (TBCs) can help develop reliable and durable TBCs for advanced gas turbine engines. One of the characteristics of failure in electron beam physical vapor deposited (EB-PVD) TBCs is the development of instability, named rumpling, at the interface between (Ni, Pt)Al bond coat and thermally grown oxide (TGO). In this study, thermal cycling at 1100[degrees]C with 1 hr dwell time was carried out on 25.4mm disc specimens of...
Show moreA detailed understanding of failure mechanisms in thermal barrier coatings (TBCs) can help develop reliable and durable TBCs for advanced gas turbine engines. One of the characteristics of failure in electron beam physical vapor deposited (EB-PVD) TBCs is the development of instability, named rumpling, at the interface between (Ni, Pt)Al bond coat and thermally grown oxide (TGO). In this study, thermal cycling at 1100[degrees]C with 1 hr dwell time was carried out on 25.4mm disc specimens of TBCs that consisted of EB-PVD coated ZrO2-7wt.%Y2O3, (Pt,Ni)Al bond coat, and CMSX-4 Ni-based superalloy. At specific fraction of lifetime,TBCs were examined by electron microscopy and photostimulated luminescence (PL). Changes in the average compressive residual stress of the TGO determined by PL and the magnitude of rumpling, determined by tortuosity from quantitative microstructural analyses, were examined with respect to the furnace thermal cyclic lifetime and microstructural evolution of TBCs. The combination of elastic strain energy within the TGO and interfacial energy at the interface between the TGO and the bond coat was defined as the TGO energy, and its variation with cyclic oxidation time was found to remain approximately constant ~135J/m2 during thermal cycling from 10% to 80% thermal cyclic lifetime. Parametric study at ~135J/m2 was performed and variation in residual stress with rumpling for different oxide scale thicknesses was examined. This study showed that the contribution of rumpling in residual stress relaxation decreased with an increase in TGO thickness. High pressure turbine blades serviced for 2843 hours and in the as coated form were also examined using electron microscopy and photostimulated luminescence. The difference in residual stress values obtained using PL on the suction and pressure sides of as-coated turbine blade were discussed. The presence of a thick layer of deposit on the serviced blade gave signals from stress free alpha-Al2O3 in the deposit, not from the TGO. The TGO growth constant data from the disc-shape TBCs, thermally cycled at 1100[degrees]C, and studies by other authors at different temperatures but on similar EB-PVD coated TBCs with (Pt, Ni)Al bond coat and CMSX-4 Ni- based superalloy were used to determine the temperature profile at the YSZ/bond coat interface. The interfacial temperature profiles of the serviced blade and the YSZ thickness profile were compared to document the variable temperature exposure at the leading edge, trailing edge, suction and the pressure side.
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Date Issued: 2011
Identifier: CFE0003927, ucf:48700
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003927

Title: Neurological profile of older ApoE-PON1 double knockout mice.
Creator: Mitra, Connie, Parthasarathy, Sampath, Kim, Yoon-Seong, Zhao, Jihe, University of Central Florida
Abstract / Description: Atherosclerosis is a cardiovascular disease where plaques made up of lipids in the form of cholesterol ester build up in the carotid and innominate arteries that supply blood to the brain. Accumulation of the plaques limit the flow of blood and nutrients to the brain, leading to diminished oxygen supply, increased oxidative stress and cell death. All these have been implicated in Alzheimer's disease (AD). Alzheimer's disease, a chronic, progressive, age related neurodegenerative disorder is...
Show moreAtherosclerosis is a cardiovascular disease where plaques made up of lipids in the form of cholesterol ester build up in the carotid and innominate arteries that supply blood to the brain. Accumulation of the plaques limit the flow of blood and nutrients to the brain, leading to diminished oxygen supply, increased oxidative stress and cell death. All these have been implicated in Alzheimer's disease (AD). Alzheimer's disease, a chronic, progressive, age related neurodegenerative disorder is the most common form of dementia in the elderly accounting for 60-80% of the cases. Clinically, Alzheimer's disease is characterized by loss of memory, damage of brain tissues, and neuronal and synaptic loss. Pathologically, it is delineated by accumulation of amyloid beta and tau proteins forming senile plaques and neurofibrillary tangles respectively. Apolipoprotein E (ApoE) polymorphism, increased oxidative stress and products of lipid peroxidation are associated with atherosclerosis and Alzheimer's disease. ApoE is a glycosylated protein that mediates plasma lipoprotein metabolism. ApoE isoforms have differential effect on amyloid beta aggregation and clearance, thus playing an important role in Alzheimer's pathology. Serum paraoxonase 1 (PON1) is a lipoprotein associated antioxidant enzyme that prevents lipid peroxidation. S100B protein is a plasma biomarker, altered expression of which has been implied in AD. We propose the hypothesis that combined deficiencies in apolipoprotein E and antioxidant defense (established by the lack of PON1), together with dyslipidemia and development of carotid atherosclerosis in aging mice would reflect Alzheimer's pathology. The brains of young and old ApoE-PON1 double knockout (DKO) mice and control C57BL/6J mice were harvested. Atherosclerotic lesions were quantified by Image J. RNA was isolated, cDNA was synthesized and quantitative RT-PCR was performed to detect mRNA levels of S100B. Blood levels of S100B protein was measured by ELISA. Brain tissues were stained with Hematoxylin and Eosin stain and 4G8 immunostain to detect histopathological changes. The blood brain barrier (BBB) is altered in AD resulting in increased permeability and vascular dysfunction. The vascular permeability of BBB was analyzed by Evans Blue Dye (EBD) assay. The results showed that the older DKO mice had severe carotid atherosclerosis, increased levels of serum S100B protein and elevated mRNA levels of S100B. Histological examination showed the presence of characteristic hallmarks of AD. The leakage of EBD into brain parenchyma indicated disruption of BBB. The results suggest that diminished blood flow and nutrient supply to the brain due to atherosclerosis and increased oxidative stress might contribute to Alzheimer's pathology. We suggest that older ApoE-PON1 DKO mice may serve as a model of Alzheimer's disease and prevention of atherosclerosis might promote regression of Alzheimer's disease.
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Date Issued: 2016
Identifier: CFE0006483, ucf:51407
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006483

Title: AN ANALYSIS OF FACTORS THAT INFLUENCED BREVARD STUDENTS TO DROP OUT AND WHY THEY RETURNED TO EARN THEIR GENERAL EDUCATION DEVELOPMENT (GED) DIPLOMA.
Creator: Spadaccini, Becky, Murray, Barbara, University of Central Florida
Abstract / Description: Dropping out of high school almost guarantees a life of hardship. The absence of a diploma contributes to poverty, increased crime rates and weakens the economy. To that end, school districts have a moral and ethical responsibility to bring an end to the dropout epidemic. This study was based on an analysis of more than 26,000 Brevard public school students. The researcher used 2006-2007, 2007-2008 and 2008-2009 student data to determine the relationship between race, grade level, ESE status,...
Show moreDropping out of high school almost guarantees a life of hardship. The absence of a diploma contributes to poverty, increased crime rates and weakens the economy. To that end, school districts have a moral and ethical responsibility to bring an end to the dropout epidemic. This study was based on an analysis of more than 26,000 Brevard public school students. The researcher used 2006-2007, 2007-2008 and 2008-2009 student data to determine the relationship between race, grade level, ESE status, ELL status, SES, type of promotion and dropping out of school. In addition, the researcher reviewed Student Exit Survey data and face-to-face interview data to determine why students dropped out and identified strategies students felt would have kept them in school. Finally, individual interview data were analyzed to understand the circumstances that encouraged participants to return to earn their diplomas. The researcher recommended use of data management and tracking systems for early identification of potential dropouts so intervention could be delivered at the onset of failure, assignment of trained adult leaders to monitor and intervene for students; enforcement of compulsory school attendance; creation of mechanisms to reduce absenteeism that do not lead to school failure; required intervention for students who are truant; identification and assignment of highly effective teachers to at-risk youth; intervention in classrooms that have high rates of student failure; use of relevant curriculum and employment of instructional practices proven to increase engagement; alignment of intervention strategies with researched practices; gathering of input and feedback from students to determine program effectiveness; creation of meaningful exit interview processes; utilization of survey data to identify and remove school-related barriers and collaboration with community agencies to find meaningful and genuine solutions for students in crisis.
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Date Issued: 2011
Identifier: CFE0003578, ucf:48898
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003578

barriers (7)	+ -
Barriers (5)	+ -
barrier (4)	+ -
Thermal Barrier Coatings (3)	+ -
thermal barrier coatings (3)	+ -

Communication (2)	+ -
Nursing (2)	+ -
TBC (2)	+ -
education (2)	+ -
nurse (2)	+ -
older adults (2)	+ -
perception (2)	+ -
residual stress (2)	+ -
stress (2)	+ -
synchrotron (2)	+ -
technology integration (2)	+ -
thermal barrier coating (2)	+ -
thermally grown oxide (2)	+ -
x-ray diffraction (2)	+ -
(Pt (1)	+ -
2+2 program (1)	+ -
AM (1)	+ -
Absorptive Materials (1)	+ -
Absorptive Treatments (1)	+ -
Access (1)	+ -
Alzheimer's disease (1)	+ -
Amyloid beta plaques (1)	+ -
Atherosclerosis (1)	+ -
Attitudes (1)	+ -
Blood Brain barrier (1)	+ -

ETD Collection (32)	+ -
Honors Collection (10)	+ -

University of Central Florida (42)	+ -
Sohn, Yongho (8)	+ -
Raghavan, Seetha (4)	+ -
An, Linan (3)	+ -
D'Amato-Kubiet, Leslee (2)	+ -

Elshennawy, Ahmad (2)	+ -
Ghosh, Ranajay (2)	+ -
Gordon, Ali (2)	+ -
Kapat, Jayanta (2)	+ -
Kim, Yoon-Seong (2)	+ -
Lee, Gene (2)	+ -
Rabelo, Luis (2)	+ -
Vaidyanathan, Raj (2)	+ -
Wayson, Roger (2)	+ -
Zhai, Lei (2)	+ -
Allen, Kay (1)	+ -
Allred, Kelly (1)	+ -
Alyousef, Abdulwahab (1)	+ -
Andejany, Murad (1)	+ -
Applen, John (1)	+ -
Arner, Wayne (1)	+ -
Bai, Yuanli (1)	+ -
Baldwin, Lee (1)	+ -
Bargraser, Carmen (1)	+ -
Blackwell, Christopher (1)	+ -
Bowerman, Kamra (1)	+ -
Brady, Claire (1)	+ -
Brandenburg, Sara J (1)	+ -
Breit, Elyse (1)	+ -
Brown, Timothy (1)	+ -

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