ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
Displaying 1 - 10 of 74
Description
Perceptual learning by means of coherent motion training paradigms has been shown to produce plasticity in lower and higher-level visual systems within the human occipital lobe both supra- and subliminally. However, efficiency of training methods that produce consolidation in the visual system via coherent motion has yet to be experimentally determined. Furthermore, the effects of coherent motion training on reading comprehension, in clinical and normal populations, are still nascent. In the present study, 20 participants were randomly assigned to one of four experimental conditions. Two conditions had a participation requirement of four days while two conditions required eight days of participation. These conditions were further divided into 500 or 1000 trials per day (4 x 500, 4 x 1000, 8 x 500, 8 x 1000). Additional pre-test and post-test days were used to attain timed pre- and post-tests on the Wide Range Achievement Test IV (WRAT IV) reading comprehension battery. Furthermore, a critical flicker fusion threshold (CFFT) score was taken on a macular pigment densitometer on the pre-test and post-test day. Participants showed significant improvement in CFFT levels, WRAT IV reading comprehension, and speed of completion between pre-test and post-test; however, degree of improvement did not vary as a function of training condition. An interaction between training condition and degree of improvement was evident in coherent dot motion contrast scores, with significant training plasticity occurring in the 4 x 1000 and 8 x 500 conditions.
ContributorsGroth, Anthony (Author) / Náñez, José E. (Thesis advisor) / Hall, Deborah (Committee member) / Risko, Evan F. (Committee member) / Arizona State University (Publisher)
Created2013
Description
Recent research has identified affirmation of transcendence and exposure to violent Bible verses as being related to greater prejudice toward value-violating out-groups (Blogowska & Saroglou, 2012; Shen et al., 2013). Effects of exposure to specific Bible verses on attitudes toward out-groups have not been measured in combination with the Post-Critical Belief Scale developed by Hutsebaut (1996). The relationships between exposure to scriptural endorsements of prejudice, affirmation vs. disaffirmation of transcendence, literal vs. symbolic processing of religious content, and prejudice toward value-violating out-groups were examined using an online survey administered to a sample of U.S. adults (N=283). Greater affirmation of transcendence scores were linked to greater prejudice toward atheists and homosexuals and more favorable ratings of Christians and highly religious people. Lower affirmation of transcendence scores were linked to less favorable ratings of Christians and highly religious people and more favorable ratings of atheists. Exposure to scriptural endorsements of prejudice did not have a significant effect on levels of prejudice in this study.
ContributorsGrove, Richard (Author) / Robles, Elías (Thesis advisor) / Hall, Deborah (Committee member) / Schweitzer, Nicholas (Committee member) / Arizona State University (Publisher)
Created2013
Description
While acceptance towards same-sex marriage is gradually increasing, same-sex marriage is banned in many states within the United States. Laws that prohibit same-sex couples from marrying have been shown to increase feelings of depression, exclusion, and stigma for same-sex attracted individuals. The intention of this study was to explore the effect both pro- and anti-same-sex marriage advertisements have on heterosexual individuals' implicit attitudes towards same-sex couples. It was predicted that exposure to anti-same-sex advertisements would lead to viewing same-sex couples as more unpleasant and heterosexual couples as being more pleasant. However, heterosexual participants who viewed anti-same-sex marriage ads were more likely to rate heterosexual couples as being unpleasant and same-sex couples as pleasant. It is theorized that viewing anti-same-sex marriage advertisements led heterosexual individuals to report heterosexual stimuli as being more unpleasant compared to same-sex stimuli as a form of defensive processing.
ContributorsWalsh, Theodora Michelle (Author) / Newman, Matt (Thesis advisor) / Hall, Deborah (Committee member) / Salerno, Jessica (Committee member) / Arizona State University (Publisher)
Created2013
Description
Ingestion of high temperature mainstream gas into the rotor-stator cavities of a gas turbine is one of the major problems faced by the turbine designers. The ingested gas heats up rotor disks and induces higher thermal stresses on them, giving rise to durability concern. Ingestion is usually reduced by installing seals on the rotor and stator rims and by purging the disk cavity by secondary air bled from the compressor discharge. The geometry of the rim seals and the secondary air flow rate, together, influence the amount of gas that gets ingested into the cavities. Since the amount of secondary air bled off has a negative effect on the gas turbine thermal efficiency, one goal is to use the least possible amount of secondary air. This requires a good understanding of the flow and ingestion fields within a disk cavity. In the present study, the mainstream gas ingestion phenomenon has been experimentally studied in a model single-stage axial flow gas turbine. The turbine stage featured vanes and blades, and rim seals on both the rotor and stator. Additionally, the disk cavity contained a labyrinth seal radially inboard which effectively divided the cavity into a rim cavity and an inner cavity. Time-average static pressure measurements were obtained at various radial positions within the disk cavity, and in the mainstream gas path at three axial locations at the outer shroud spread circumferentially over two vane pitches. The time-average static pressure in the main gas path exhibited a periodic asymmetry following the vane pitch whose amplitude diminished with increasing distance from the vane trailing edge. The static pressure distribution increased with the secondary air flow rate within the inner cavity but was found to be almost independent of it in the rim cavity. Tracer gas (CO2) concentration measurements were conducted to determine the sealing effectiveness of the rim seals against main gas ingestion. For the rim cavity, the sealing effectiveness increased with the secondary air flow rate. Within the inner cavity however, this trend reversed -this may have been due to the presence of rotating low-pressure flow structures inboard of the labyrinth seal.
ContributorsThiagarajan, Jayanth kumar (Author) / Roy, Ramendra P (Thesis advisor) / Lee, Taewoo (Committee member) / Mignolet, Marc (Committee member) / Arizona State University (Publisher)
Created2013
Description
Shock loading is a complex phenomenon that can lead to failure mechanisms such as strain localization, void nucleation and growth, and eventually spall fracture. Studying incipient stages of spall damage is of paramount importance to accurately determine initiation sites in the material microstructure where damage will nucleate and grow and to formulate continuum models that account for the variability of the damage process due to microstructural heterogeneity. The length scale of damage with respect to that of the surrounding microstructure has proven to be a key aspect in determining sites of failure initiation. Correlations have been found between the damage sites and the surrounding microstructure to determine the preferred sites of spall damage, since it tends to localize at and around the regions of intrinsic defects such as grain boundaries and triple points. However, considerable amount of work still has to be done in this regard to determine the physics driving the damage at these intrinsic weak sites in the microstructure. The main focus of this research work is to understand the physical mechanisms behind the damage localization at these preferred sites. A crystal plasticity constitutive model is implemented with different damage criteria to study the effects of stress concentration and strain localization at the grain boundaries. A cohesive zone modeling technique is used to include the intrinsic strength of the grain boundaries in the simulations. The constitutive model is verified using single elements tests, calibrated using single crystal impact experiments and validated using bicrystal and multicrystal impact experiments. The results indicate that strain localization is the predominant driving force for damage initiation and evolution. The microstructural effects on theses damage sites are studied to attribute the extent of damage to microstructural features such as grain orientation, misorientation, Taylor factor and the grain boundary planes. The finite element simulations show good correlation with the experimental results and can be used as the preliminary step in developing accurate probabilistic models for damage nucleation.
ContributorsKrishnan, Kapil (Author) / Peralta, Pedro (Thesis advisor) / Mignolet, Marc (Committee member) / Sieradzki, Karl (Committee member) / Jiang, Hanqing (Committee member) / Oswald, Jay (Committee member) / Arizona State University (Publisher)
Created2013
Description
This study investigates the presence of a dual identity defendant, and how sharing an in-group can create a judgment bias. A sample of 256 participants was used to test whether there was a relationship between judgment punitiveness, perceptions of shared identity, hypocrisy and the social identities (religion and sexual orientation) of the participants and a defendant charges with a sexual offence. Results suggest that Christian participants selected more punitive outcomes for the defendant compared to non-Christian participants. Further, participants were more punitive when the defendant was gay compared to when the defendant was heterosexual. Also, when the defendant was straight there was a stronger feeling of similarity between the participants and defendant compared to when the defendant was gay, and non-Christian participants had a stronger feeling of closeness to the defendant compared to Christian participants. There was a significant interaction found, suggesting that when the defendant was Christian and gay he was seen as more hypocritical compared to when he was Christian and straight; there was no interaction when the defendant was not Christian. These findings should aid in future research and a better understanding of how dual identity defendants are perceived in the courtroom.
ContributorsAltholz, Rachel Leah (Author) / Salerno, Jessica (Thesis advisor) / Hall, Deborah (Committee member) / Schweitzer, Nick (Committee member) / Arizona State University (Publisher)
Created2014
Description
Interest in health and wellness has significantly increased in today's society. Living a healthy and active lifestyle is suggested to promote overall physical and psychological well-being. This study explored the effects of wearing a Fitbit Zip activity monitor and the impact of expressing mindfulness on levels of physical activity. It was predicted that expressing mindfulness, as measured by the use of present-tense language during the daily emotional writing task, would moderate the relationship between wearing a Fitbit Zip activity monitor and change in physical activity. Specifically, it was hypothesized daily monitoring would only lead to increased activity among those higher in mindful language. Over the course of five days, participants were asked to wear a Fitbit Zip and to complete a daily questionnaire and writing task at the end of each evening. On the last day of the study, participants completed a follow-up assessment, which suggested that the combination of wearing a Fitbit Zip activity monitor and expressing more mindfulness throughout the week increased levels of physical activity. An important issue for future research is to conduct this study for a longer period of time in order to get more variability in the data. However, despite the limitations of the design, these findings suggest that activity monitoring may be a promising way to promote healthy lifestyle change.
ContributorsTarachiu, Viorela (Author) / Newman, Matt L. (Thesis advisor) / Hall, Deborah (Committee member) / Salerno, Jessica (Committee member) / Arizona State University (Publisher)
Created2014
Description
As robots are increasingly migrating out of factories and research laboratories and into our everyday lives, they should move and act in environments designed for humans. For this reason, the need of anthropomorphic movements is of utmost importance. The objective of this thesis is to solve the inverse kinematics problem of redundant robot arms that results to anthropomorphic configurations. The swivel angle of the elbow was used as a human arm motion parameter for the robot arm to mimic. The swivel angle is defined as the rotation angle of the plane defined by the upper and lower arm around a virtual axis that connects the shoulder and wrist joints. Using kinematic data recorded from human subjects during every-day life tasks, the linear sensorimotor transformation model was validated and used to estimate the swivel angle, given the desired end-effector position. Defining the desired swivel angle simplifies the kinematic redundancy of the robot arm. The proposed method was tested with an anthropomorphic redundant robot arm and the computed motion profiles were compared to the ones of the human subjects. This thesis shows that the method computes anthropomorphic configurations for the robot arm, even if the robot arm has different link lengths than the human arm and starts its motion at random configurations.
ContributorsWang, Yuting (Author) / Artemiadis, Panagiotis (Thesis advisor) / Mignolet, Marc (Committee member) / Santos, Veronica J (Committee member) / Arizona State University (Publisher)
Created2013
Description
A sample of 193 participants viewed one of six variations of an eyewitness giving mock testimony. Each participant viewed testimony, which varied by level of emotion (none, moderate, or high) and frame (waist-up or head only). Participants then rated the witness using the Brodsky Witness Credibility Scale and the Reyson Likability Scale. A set of ANOVA's was performed revealing an effect of emotion level on both credibility and likability. Emotion level was found to influence participant judgments of poise, however, to a lesser degree than judgments of credibility and likability. These results suggest that attorneys may want to avoid the use of videoconferencing with certain types of witnesses where testimony may be highly emotional.
ContributorsHavener, Shannon (Author) / Schweitzer, Nicholas (Thesis advisor) / Salerno, Jessica (Committee member) / Hall, Deborah (Committee member) / Arizona State University (Publisher)
Created2014
Description
Past research suggested that lutein (L) and zeaxanthin (Z) play a role in many aspects of cognitive functions including motor speed, working memory, executive function, psychomotor speed and verbal fluency among elderly people. Moreover, L and Z are the only carotenoids found in the eye, and they are correlated with improved contrast sensitivity, improved temporal vision, reduced glare disability, and reduced risk of age related-macular degeneration (AMD). Animal and postmortem research suggests that MPOD may be a biomarker for predicting cognitive decline with age. The purpose of this study is to evaluate the potential relationship between MPOD and cognition in young healthy adults. There were fifty participants in the current study, 25 had low MPOD. The remaining participants exhibited high MPOD, which was measured using a macular pigment densitometer. People with low MPOD did not perform any worse than people with high MPOD. Although low MPOD in young adults may be a biomarker for future cognitive decline, the effects may lay dormant until later in life. Future research should explore this possibility by replicating this study with an older population.
ContributorsZimmerman, Daniel (Author) / Nanez, Jose E (Thesis advisor) / Shipstead, Zachary (Committee member) / Hall, Deborah (Committee member) / Arizona State University (Publisher)
Created2014