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- Creators: Barrett, The Honors College
Description
Modern day gas turbine designers face the problem of hot mainstream gas ingestion into rotor-stator disk cavities. To counter this ingestion, seals are installed on the rotor and stator disk rims and purge air, bled off from the compressor, is injected into the cavities. It is desirable to reduce the supply of purge air as this decreases the net power output as well as efficiency of the gas turbine. Since the purge air influences the disk cavity flow field and effectively the amount of ingestion, the aim of this work was to study the cavity velocity field experimentally using Particle Image Velocimetry (PIV). Experiments were carried out in a model single-stage axial flow turbine set-up that featured blades as well as vanes, with purge air supplied at the hub of the rotor-stator disk cavity. Along with the rotor and stator rim seals, an inner labyrinth seal was provided which split the disk cavity into a rim cavity and an inner cavity. First, static gage pressure distribution was measured to ensure that nominally steady flow conditions had been achieved. The PIV experiments were then performed to map the velocity field on the radial-tangential plane within the rim cavity at four axial locations. Instantaneous velocity maps obtained by PIV were analyzed sector-by-sector to understand the rim cavity flow field. It was observed that the tangential velocity dominated the cavity flow at low purge air flow rate, its dominance decreasing with increase in the purge air flow rate. Radially inboard of the rim cavity, negative radial velocity near the stator surface and positive radial velocity near the rotor surface indicated the presence of a recirculation region in the cavity whose radial extent increased with increase in the purge air flow rate. Qualitative flow streamline patterns are plotted within the rim cavity for different experimental conditions by combining the PIV map information with ingestion measurements within the cavity as reported in Thiagarajan (2013).
ContributorsPathak, Parag (Author) / Roy, Ramendra P (Thesis advisor) / Calhoun, Ronald (Committee member) / Lee, Taewoo (Committee member) / Arizona State University (Publisher)
Created2013
Description
Over the past three decades, particle image velocimetry (PIV) has been continuously growing to become an informative and robust experimental tool for fluid mechanics research. Compared to the early stage of PIV development, the dynamic range of PIV has been improved by about an order of magnitude (Adrian, 2005; Westerweel et al., 2013). Further improvement requires a breakthrough innovation, which constitutes the main motivation of this dissertation. N-pulse particle image velocimetry-accelerometry (N-pulse PIVA, where N>=3) is a promising technique to this regard. It employs bursts of N pulses to gain advantages in both spatial and temporal resolution. The performance improvement by N-pulse PIVA is studied using particle tracking (i.e. N-pulse PTVA), and it is shown that an enhancement of at least another order of magnitude is achievable. Furthermore, the capability of N-pulse PIVA to measure unsteady acceleration and force is demonstrated in the context of an oscillating cylinder interacting with surrounding fluid. The cylinder motion, the fluid velocity and acceleration, and the fluid force exerted on the cylinder are successfully measured. On the other hand, a key issue of multi-camera registration for the implementation of N-pulse PIVA is addressed with an accuracy of 0.001 pixel. Subsequently, two applications of N-pulse PTVA to complex flows and turbulence are presented. A novel 8-pulse PTVA analysis was developed and validated to accurately resolve particle unsteady drag in post-shock flows. It is found that the particle drag is substantially elevated from the standard drag due to flow unsteadiness, and a new drag correlation incorporating particle Reynolds number and unsteadiness is desired upon removal of the uncertainty arising from non-uniform particle size. Next, the estimation of turbulence statistics utilizes the ensemble average of 4-pulse PTV data within a small domain of an optimally determined size. The estimation of mean velocity, mean velocity gradient and isotropic dissipation rate are presented and discussed by means of synthetic turbulence, as well as a tomographic measurement of turbulent boundary layer. The results indicate the superior capability of the N-pulse PTV based method to extract high-spatial-resolution high-accuracy turbulence statistics.
ContributorsDing, Liuyang (Author) / Adrian, Ronald J (Thesis advisor) / Frakes, David (Committee member) / Herrmann, Marcus (Committee member) / Huang, Huei-Ping (Committee member) / Peet, Yulia (Committee member) / Arizona State University (Publisher)
Created2018
Description
Rapid expansion of dense beds of fine, spherical particles subjected to rapid depressurization is studied in a vertical shock tube. As the particle bed is unloaded, a high-speed video camera captures the dramatic evolution of the particle bed structure. Pressure transducers are used to measure the dynamic pressure changes during the particle bed expansion process. Image processing, signal processing, and Particle Image Velocimetry techniques, are used to examine the relationships between particle size, initial bed height, bed expansion rate, and gas velocities.
The gas-particle interface and the particle bed as a whole expand and evolve in stages. First, the bed swells nearly homogeneously for a very brief period of time (< 2ms). Shortly afterward, the interface begins to develop instabilities as it continues to rise, with particles nearest the wall rising more quickly. Meanwhile, the bed fractures into layers and then breaks down further into cellular-like structures. The rate at which the structural evolution occurs is shown to be dependent on particle size. Additionally, the rate of the overall bed expansion is shown to be dependent on particle size and initial bed height.
Taller particle beds and beds composed of smaller-diameter particles are found to be associated with faster bed-expansion rates, as measured by the velocity of the gas-particle interface. However, the expansion wave travels more slowly through these same beds. It was also found that higher gas velocities above the the gas-particle interface measured \textit{via} Particle Image Velocimetry or PIV, were associated with particle beds composed of larger-diameter particles. The gas dilation between the shocktube diaphragm and the particle bed interface is more dramatic when the distance between the gas-particle interface and the diaphragm is decreased-as is the case for taller beds.
To further elucidate the complexities of this multiphase compressible flow, simple OpenFOAM (Weller, 1998) simulations of the shocktube experiment were performed and compared to bed expansion rates, pressure fluctuations, and gas velocities. In all cases, the trends and relationships between bed height, particle diameter, with expansion rates, pressure fluctuations and gas velocities matched well between experiments and simulations. In most cases, the experimentally-measured bed rise rates and the simulated bed rise rates matched reasonably well in early times. The trends and overall values of the pressure fluctuations and gas velocities matched well between the experiments and simulations; shedding light on the effects each parameter has on the overall flow.
The gas-particle interface and the particle bed as a whole expand and evolve in stages. First, the bed swells nearly homogeneously for a very brief period of time (< 2ms). Shortly afterward, the interface begins to develop instabilities as it continues to rise, with particles nearest the wall rising more quickly. Meanwhile, the bed fractures into layers and then breaks down further into cellular-like structures. The rate at which the structural evolution occurs is shown to be dependent on particle size. Additionally, the rate of the overall bed expansion is shown to be dependent on particle size and initial bed height.
Taller particle beds and beds composed of smaller-diameter particles are found to be associated with faster bed-expansion rates, as measured by the velocity of the gas-particle interface. However, the expansion wave travels more slowly through these same beds. It was also found that higher gas velocities above the the gas-particle interface measured \textit{via} Particle Image Velocimetry or PIV, were associated with particle beds composed of larger-diameter particles. The gas dilation between the shocktube diaphragm and the particle bed interface is more dramatic when the distance between the gas-particle interface and the diaphragm is decreased-as is the case for taller beds.
To further elucidate the complexities of this multiphase compressible flow, simple OpenFOAM (Weller, 1998) simulations of the shocktube experiment were performed and compared to bed expansion rates, pressure fluctuations, and gas velocities. In all cases, the trends and relationships between bed height, particle diameter, with expansion rates, pressure fluctuations and gas velocities matched well between experiments and simulations. In most cases, the experimentally-measured bed rise rates and the simulated bed rise rates matched reasonably well in early times. The trends and overall values of the pressure fluctuations and gas velocities matched well between the experiments and simulations; shedding light on the effects each parameter has on the overall flow.
ContributorsZunino, Heather (Author) / Adrian, Ronald J (Thesis advisor) / Clarke, Amanda (Committee member) / Chen, Kangping (Committee member) / Herrmann, Marcus (Committee member) / Huang, Huei-Ping (Committee member) / Arizona State University (Publisher)
Created2019
Description
Health and fast food are seemingly on two opposite ends of the spectrum, yet healthy fast food is quickly growing in popularity. As many fast food brands are adjusting their menu to accommodate to this trend, this study explores how health claims used in fast food advertising affect college students' perceptions of health and their likelihood to purchase healthy fast food products. To test this, a survey gathered quantitative data to assess student's perceptions of health and fast food, as well as qualitative data of when eating healthy is appealing and unappealing. An ad manipulation was employed to test student's likelihood to purchase the product shown in the ad. Though the study did not yield significant results, the results collected indicate that health claims may not be enough to influence someone to purchase, but that taste is of student's highest priority when making food purchase decisions. Thus, the study opens the door for future research in this realm of health and fast food, and concludes with recommendations for both marketers and future researchers.
ContributorsMigray, Emilee Catherine (Author) / Gray, Nancy (Thesis director) / Samper, Adriana (Committee member) / Department of Marketing (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This paper will review past unethical studies conducted in the last 100 years on humans, including studies such as the WWII Concentration Camp studies on hypothermia and sterilization, Tuskegee Syphilis Study, and the case of Henrietta Lacks; Analyze why they were deemed unethical, the laws that emerged from these studies, and how it relates to contemporary technology, with a focus on the issues surrounding the development of an electronic wearable pregnancy monitor. The studies will include details of how they were conducted as well as what deemed them unethical and an explanation of why the results are unusable. Following the studies will be an explanation of the laws that were set into place following the studies with a lead into current technologies and how these technologies created a new set of ethics. The Google Mini, the wearable biosensor onesies for infants, and the intensive care unit at Banner Baywood will be described and so will their role in the development of an electronic wearable pregnancy monitor. The mini-meta analysis includes possible features of the monitor as well as a description of what the ethical consent form will look like. To conclude the paper, the importance of analyzing past unethical studies will help create a new ethical device that will make a point to go above and beyond to ensure the physical health of unborn children, in a way that is both ethical and significant.
ContributorsWallace, Sydney Sarah (Author) / Hall, Rick (Thesis director) / Kamenca, Andrea (Committee member) / Human Systems Engineering (Contributor) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Forty collegiate gymnasts were recruited for a nutrition and health study. Participants must have been at least eighteen years old at Arizona State University (ASU) in the club or team gymnastics program. The Institutional Review Board (IRB) reviewed and accepted my survey in order to hand out to the gymnasts. The ASU club and team coach and the ASU study team also approved my survey. As soon as the survey was approved, it was emailed to all of the gymnasts. ASU gymnasts were surveyed on nutritional knowledge and personal health. Subjects answered a quiz on nutrient needs and serving sizes. Personal questions consisted of height, weight, injuries, body image, and typical meal plans. Gymnasts were given a $10 compensation to increase the participation. We found that only 16% of gymnasts surveyed scored a 70% or higher on their nutritional knowledge. Although these gymnasts do not have adequate knowledge, the majority consume a healthy diet. Diets included fruits, vegetables, protein-rich foods, and few high fat and sugary foods. Four of the gymnasts had one or fewer injuries in the past two years, although, four gymnasts also had three or more injuries. No correlation was found between diet and injuries. There was also no correlation between the gymnast's nutritional knowledge and their health.
ContributorsKugler, Natalie K. (Author) / Levinson, Simin (Thesis director) / Berger, Christopher (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
According to the CDC, diabetes is the 7th leading cause of death in the U.S. and rates are continuing to rise nationally and internationally. Chronically elevated blood glucose levels can lead to type 2 diabetes and other complications. Medications can be used to treat diabetes, but often have side effects. Lifestyle and diet modifications can be just as effective as medications in helping to improve glycemic control, and prevent diabetes or improve the condition in those who have it. Studies have demonstrated that consuming vinegar with carbohydrates can positively impact postprandial glycemia in diabetic and healthy individuals. Continuous vinegar intake with meals may even reduce fasting blood glucose levels. Since vinegar is a primary ingredient in mustard, the purpose of this study was to determine if mustard consumption with a carbohydrate-rich meal (bagel and fruit juice) had an effect on the postprandial blood glucose levels of subjects. The results showed that mustard improved glycemia by 17% when subjects consumed the meal with mustard as opposed to the control. A wide variety of vinegars exists. The defining ingredient in all vinegars is acetic acid, behind the improvement in glycemic response observed with vinegar ingestion. Vinegar-containing foods range from mustard, to vinaigrette dressings, to pickled foods. The benefits of vinegar ingestion with carbohydrates are dose-dependent, meaning that adding even small amounts to meals can help. Making a conscious effort to incorporate these foods into meals, in addition to an overall healthy lifestyle, could provide an additional tool for diabetics and nondiabetics alike to consume carbohydrates in a healthier manner.
ContributorsJimenez, Gabriela (Author) / Johnston, Carol (Thesis director) / Lespron, Christy (Committee member) / School of Nutrition and Health Promotion (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Because children do not have the same decision-making powers as adults in matters affecting their health, their opinions have often been underrepresented in research (Bradding & Horstman, 1999). However, there is growing interest in the way that children view health because this knowledge elicits the development of more child-centered and effective approaches to health education and intervention (Bradding & Horstman, 1999). Professionals have often utilized the write-and-draw technique in school settings to gain a better understanding of how to best implement health education programs. The "bottom-up" approach of the write-and-draw method encourages participation and has been shown to elicit thoughtful responses about how children conceptualize health (Pridmore & Bendelow, 1995). This study uses the write-and-draw method to perform a cross- cultural comparison of child perspectives of health in the United States and Guatemala, countries that represent contrasting paradigms for child health. The results of this study are consistent with previous research, especially the emergent health themes. Children from the United States and Guatemala predominantly depicted health in terms of food. Guatemalan students were more likely to refer to hygienic practices and environmental conditions, while US children mentioned vegetables, water, and exercise as being healthy. For the unhealthy category, themes of poor hygiene, chips, fat/grease, fruit, carbohydrates, and environment were mentioned more often in Guatemala, while U.S. students listed sweets and fast food more frequently. Results support claims made in other literature that children's concepts of health are shaped by life experience and social context. Potential applications of the research include exposing areas (themes) where children are less likely to understand health implications and developing educational curriculum to increase a more comprehensive understanding of health.
ContributorsRenslow, Jillian Marie (Author) / Maupin, Jonathan (Thesis director) / BurnSilver, Shauna (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of International Letters and Cultures (Contributor)
Created2015-05
Description
The purpose of this project was to establish a digital and social media presence to support a personal fitness trainer and d�TERRA essential oils wellness advocate in growing her health and wellness businesses. The first portion explores the role of digital and social media tools for health and wellness professionals. It incorporates use of both secondary and primary research methods including focus groups and in-depth interviews. The second portion is a campaign proposal that serves as a creative response to the research and findings of the first portion. The proposal includes recommendations for strategic use of new brand building and social networking tools such as a personal website, Facebook, Twitter, LinkedIn and About.Me pages. It also offers collateral material for brand outreach, social media calendars and a 10-page social media guidebook offering suggestions on how to strategically implement the campaign elements.
ContributorsNichols, Emily Jaye (Author) / Wu, Xu (Thesis director) / Roschke, Kristy (Committee member) / Barrett, The Honors College (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor)
Created2015-05
Description
Obesity has become a major area of research in many fields due to the increasing obesity rate not only in The United States, but also around the world. Research concerning obesity stigma has both physical and mental health implications. Weight bias and obesity stigma represent important research areas for health professionals as they confront these issues on a daily basis in interactions with their patients. To explore how gender, ethnicity, and a person's own BMI affect the stigma of certain weight related terms, a set of 264 participant's surveys on weight related situations on the campus of Arizona State University were analyzed. Using univariate analysis to determine frequency of words deemed most or least acceptable as well as independent t-test for gender and ANOVA for ethnicity and own BMI, we found that participant's view more clinical terms such as "unhealthy BMI" and "BMI" as acceptable words for use during a physician-patient interaction. Analysis across genders revealed the highest number of differences in terms, with females generally ranking terms across the board as less acceptable then men. Differences varied little between ethnicities; however, own BMI revealed more differences between terms; underweight participants did not rank any terms as positive. We analyzed average ATOP (Attitudes Toward Obese People) scores and found that there was no significant difference in average ATOP scores between gender and a participant's own BMI, but a statistical significance did exist between ethnic categories. This study showed that the term "obese/obesity", although normally considered to be a clinical term by many was not ranked as very positive across gender, ethnicity, or own BMI. Based on these findings, new material should be created to inform physicians on how to talk about weight related problems with certain populations of patients.
ContributorsBlasco, Drew Adair (Author) / Wutich, Amber (Thesis director) / Brewis Slade, Alexandra (Committee member) / Barrett, The Honors College (Contributor) / School of Politics and Global Studies (Contributor) / Department of Psychology (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2014-12