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Surface Mechanical Attrition Treatment (SMAT) of 7075 Aluminum Alloy to Induce a Protective Corrosion Resistant Layer

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This paper investigates Surface Mechanical Attrition Treatment (SMAT) and the influence of treatment temperature and initial sample surface finish on the corrosion resistance of 7075-T651 aluminum alloy. Ambient SMAT was performed on AA7075 samples polished to 80-grit initial surface roughness.

This paper investigates Surface Mechanical Attrition Treatment (SMAT) and the influence of treatment temperature and initial sample surface finish on the corrosion resistance of 7075-T651 aluminum alloy. Ambient SMAT was performed on AA7075 samples polished to 80-grit initial surface roughness. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were used to characterize the corrosion behavior of samples before and after SMAT. Electrochemical tests indicated an improved corrosion resistance after application of SMAT process. The observed improvements in corrosion properties are potentially due to microstructural changes in the material surface induced by SMAT which encouraged the formation of a passive oxide layer. Further testing and research are required to understand the corrosion related effects of cryogenic SMAT and initial-surface finish as the COVID-19 pandemic inhibited experimentation plans.

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2020-05

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Evaluation of an Original Design for a Cost-Effective Wheel-Mounted Dynamometer for Road Vehicles

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This thesis evaluates the viability of an original design for a cost-effective wheel-mounted dynamometer for road vehicles. The goal is to show whether or not a device that generates torque and horsepower curves by processing accelerometer data collected at the

This thesis evaluates the viability of an original design for a cost-effective wheel-mounted dynamometer for road vehicles. The goal is to show whether or not a device that generates torque and horsepower curves by processing accelerometer data collected at the edge of a wheel can yield results that are comparable to results obtained using a conventional chassis dynamometer. Torque curves were generated via the experimental method under a variety of circumstances and also obtained professionally by a precision engine testing company. Metrics were created to measure the precision of the experimental device's ability to consistently generate torque curves and also to compare the similarity of these curves to the professionally obtained torque curves. The results revealed that although the test device does not quite provide the same level of precision as the professional chassis dynamometer, it does create torque curves that closely resemble the chassis dynamometer torque curves and exhibit a consistency between trials comparable to the professional results, even on rough road surfaces. The results suggest that the test device provides enough accuracy and precision to satisfy the needs of most consumers interested in measuring their vehicle's engine performance but probably lacks the level of accuracy and precision needed to appeal to professionals.

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2018-05

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Does Chronically Administered Intermittent Restraint Stress (IRS) have Long-Lasting Effects on Fear Extinction and Depressive-Like Behavior?

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The current study investigated whether intermittent restraint stress (IRS) would impair fear extinction learning and lead to increased anxiety and depressive- like behaviors and then be attenuated when IRS ends and a post- stress rest period ensues for 6 weeks.

The current study investigated whether intermittent restraint stress (IRS) would impair fear extinction learning and lead to increased anxiety and depressive- like behaviors and then be attenuated when IRS ends and a post- stress rest period ensues for 6 weeks. Young adult, male Sprague Dawley rats underwent restraint stress using wire mesh (6hr/daily) for five days with two days off before restraint resumed for three weeks for a total of 23 restraint days. The groups consisted of control (CON) with no restraint other than food and water restriction yoked to the restrained groups, stress immediate (STR-IMM), which were restrained then fear conditioned soon after the end of the IRS paradigm, and stress given a rest for 6 weeks before fear conditioning commenced (STR-R6). Rats were fear conditioned by pairing a 20 second tone with a footshock, then given extinction training for two days (15 tone only on each day). On the first day of extinction, all groups discriminated well on the first trial, but then as trials progressed, STR-R6 discriminated between tone and context less than did CON. On the second day of extinction, STR- IMM froze more to context in the earlier trials than compared to STR-R6 and CON. As trials progressed STR-IMM and STR-R6 froze more to context than compared to CON. Together, CON discriminated between tone and context better than did STR-IMM and STR-R6. Sucrose preference, novelty suppressed feeding, and elevated plus maze was performed after fear extinction was completed. No statistical differences were observed among groups for sucrose preference or novelty suppressed feeding. For the elevated plus maze, STR-IMM entered the open arms and the sum of both open and closed arms fewer than did STR- R6 and CON. We interpret the findings to suggest that the stress groups displayed increased hypervigilance and anxiety with STR-R6 exhibiting a unique phenotype than that of STR-IMM and CON.

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2018-05

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Effect of Student Relationships and Motivation on Student Learning and Teacher Lessons

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The fields of psychology and education are typically housed within separate contexts. Psychology is the scientific study of the mind, thoughts, behaviors and actions (Nordqvist, 2018). The history of psychology originated centuries ago in Europe, although some attribute the beginning

The fields of psychology and education are typically housed within separate contexts. Psychology is the scientific study of the mind, thoughts, behaviors and actions (Nordqvist, 2018). The history of psychology originated centuries ago in Europe, although some attribute the beginning of mind study as far back as Aristotle. Currently, the American Psychological Association has 54 active scientific divisions, ranging from the Society of Military Psychology to Psychological Hypnosis. Education, has been studied in a variety of ways, including curriculum, instruction, and educational policy. Educational psychology is a relatively new field that examines the effects of how psychological science can be applied to learning and educational success (Parankimalil, 2014). Some of the factors that educational psychologists study include: educational reform, classroom interactions, stimuli effects on learning, student motivation, individual and collective self-beliefs, goal orientation, theory of attribution, and cognitive development. It is important to distinguish that each student has a unique approach to learning. Student relationships in classrooms can profoundly impact this learning. Moreover, student motivation stems intrinsically and is influenced by external factors. Research demonstrates the positive effects sensory stimuli, including auditory, tactile, olfactory and visual, can have on student learning as well. Intrinsic and extrinsic motivation are inseparable facets of student learning, as explained by the self-determination theory. This allows for student progression from external to internal motivation, to develop better learning methods. Educational psychology is very relevant to study today, more so in a classroom where students are actively synthesizing the information learned, to apply it to real-world situations. Future research includes studying cultural effects, technology, stereotypes and reciprocal determinism in an educational setting and providing individualized learning opportunities. This research provides a transition to a student focused change rather than the cyclical model currently driving the education system today. By studying the psychological effects in a classroom, the goal is to reduce the dropout rate and improve child and adolescent education by personalizing learning.

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2018-05

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Free Bird: Preventing Sexual Assault on College Campuses

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Sexual assault affects hundreds of thousands of individuals every year. College students are especially at risk as women ages 18-24 are 3 times more likely to be a victim of sexual assault than other females (Campus Sexual Violence, n.d.). Because

Sexual assault affects hundreds of thousands of individuals every year. College students are especially at risk as women ages 18-24 are 3 times more likely to be a victim of sexual assault than other females (Campus Sexual Violence, n.d.). Because victims of sexual assault can experience negative sequelae for weeks, months, and even years after the incident occurs, it is critical to provide them with easily accessible help and guidance. For my thesis project, I investigated how sexual assault influences these victims' lives as well as what help is readily accessible to them. After researching sexual assault in college students and reading through many websites, articles, and journals, I researched the types of information provided to sexual assault victims through the websites of national sexual violence organizations. I then coded the websites of Arizona colleges and universities (N = 10) for the topics covered in their sites. Because several of these colleges had inadequate material on their websites, I developed a website that would provide additional information to sexual assault survivors. The idea of Free Bird is to establish a safe space for victims of sexual assault to find information that will allow them to heal along their journey. I learned a lot while completing this project, and I hope that the creation of this website will allow others to become more educated on the topic and realize what a problem sexual assault is in our society today.

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2018-05

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Xenophilia: The preference for members of an outgroup

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This paper explores the idea of xenophilia and the circumstances under which it may occur. Xenophilia is the preference for an outgroup member over an ingroup member. This preference does not have to be amicable, and in fact can be

This paper explores the idea of xenophilia and the circumstances under which it may occur. Xenophilia is the preference for an outgroup member over an ingroup member. This preference does not have to be amicable, and in fact can be exploitative under certain circumstances. Previous research indicates that xenophobia is much more common, but a few researchers have found support for the existence of xenophilia. To experimentally test the circumstances under which xenophilia might occur, I conducted a survey-based experiment on Amazon’s Mechanical Turk. This consisted of directed visualizations that manipulated participant goal (self-protection vs. mate acquisition) and the resources offered by both a fictitious outgroup and the hometown ingroup, followed by measures of ingroup/outgroup preference. I hypothesized that when the resource offered by the group addressed the participants’ goal, they would prefer the group with the “matched” resource—even if it was the outgroup providing that resource. My hypothesis was not supported, as the univariate analysis of variance for preference for the outgroup was not significant, F (2, 423) = .723, p = .486. This may have occurred because the goal manipulations were not strong enough to counteract the strong natural preference for ingroup members.

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2018-05

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A Comparison and Contrast of Animal Psychology in the Wild vs. the Human Dominated World

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Animal psychology is the study of how animals interact with one another, their environment, and with humans. This can be done in two different settings, the wild and captivity, and through two different approaches, academic research and practice. Academic research

Animal psychology is the study of how animals interact with one another, their environment, and with humans. This can be done in two different settings, the wild and captivity, and through two different approaches, academic research and practice. Academic research relies primarily on behavioral observation for data collection. Practice uses behavioral observation as well, but allows for a more hands on experience and lets the practitioner make improvements in the quality of life. I interviewed two people, one who practices in captivity, and one who does research in the wild. Dr. David Bunn has done research on wild animals in Kruger National Park in South Africa for over twenty years, studying human-animal interactions. Hilda Tresz has worked in zoos nearly forty years and specializes in chimps. Working within the same field, but utilizing a different setting and approach makes a big difference in the feel of the job. Though I found many differences between the two by doing my own research and from conducting interviews, there are many similarities to note as well. The general field of animal psychology is very rewarding, requires a lot of patience, and leads to a better understanding of animal behavior and how to care for specific species of animals. Working with captive animals allows for the opportunity to make a big difference in animal's lives through behavioral enrichment and general care. Working in the wild allows us to understand the innate animal behaviors displayed. Through practice, people get more hands on experience; while through research, you get to observe animals in their native habitats. Each setting and approach has it's own benefits depending on what each person's goals are for their job.

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2018-05

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In situ SEM Testing for Fatigue Crack Growth: Mechanical Investigation of Titanium

Description

Widespread knowledge of fracture mechanics is mostly based on previous models that generalize crack growth in materials over several loading cycles. The objective of this project is to characterize crack growth that occurs in titanium alloys, specifically Grade 5 Ti-6Al-4V,

Widespread knowledge of fracture mechanics is mostly based on previous models that generalize crack growth in materials over several loading cycles. The objective of this project is to characterize crack growth that occurs in titanium alloys, specifically Grade 5 Ti-6Al-4V, at the sub-cycle scale, or within a single loading cycle. Using scanning electron microscopy (SEM), imaging analysis is performed to observe crack behavior at ten loading steps throughout the loading and unloading paths. Analysis involves measuring the incremental crack growth and crack tip opening displacement (CTOD) of specimens at loading ratios of 0.1, 0.3, and 0.5. This report defines the relationship between crack growth and the stress intensity factor, K, of the specimens, as well as the relationship between the R-ratio and stress opening level. The crack closure phenomena and effect of microcracks are discussed as they influence the crack growth behavior. This method has previously been used to characterize crack growth in Al 7075-T6. The results for Ti-6Al-4V are compared to these previous findings in order to strengthen conclusions about crack growth behavior.

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2018-05

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An Examination of the Impact of Support Design on 316 Stainless Steel Supports

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The removal of support material from metal 3D printed objects is a laborious necessity for the post-processing of powder bed fusion printing (PBF). Supports are typically mechanically removed by machining techniques. Sacrificial supports are necessary in PBF printing to relieve

The removal of support material from metal 3D printed objects is a laborious necessity for the post-processing of powder bed fusion printing (PBF). Supports are typically mechanically removed by machining techniques. Sacrificial supports are necessary in PBF printing to relieve thermal stresses and support overhanging parts often resulting in the inclusion of supports in regions of the part that are not easily accessed by mechanical removal methods. Recent innovations in PBF support removal include dissolvable metal supports through an electrochemical etching process. Dissolvable PBF supports have the potential to significantly reduce the costs and time associated with traditional support removal. However, the speed and effectiveness of this approach is inhibited by numerous factors such as support geometry and metal powder entrapment within supports. To fully realize this innovative approach, it is necessary to model and understand the design parameters necessary to optimize support structures applicable to an electrochemical etching process. The objective of this study was to evaluate the impact of block additive manufacturing support parameters on key process outcomes of the dissolution of 316 stainless steel support structures. The parameters investigated included hatch spacing and perforation, and the outcomes of interests included time required for completion, surface roughness, and effectiveness of the etching process. Electrical current was also evaluated as an indicator of process completion. Analysis of the electrical current throughout the etching process showed that the dissolution is diffusion limited to varying degrees, and is dependent on support structure parameters. Activation and passivation behavior was observed during current leveling, and appeared to be more pronounced in non-perforated samples with less dense hatch spacing. The correlation between electrical current and completion of the etching process was unclear, as the support structures became mechanically removable well before the current leveled. The etching process was shown to improve surface finish on unsupported surfaces, but support was shown to negatively impact surface finish. Tighter hatch spacing was shown to correlate to larger variation in surface finish, due to ridges left behind by the support structures. In future studies, it is recommended current be more closely correlated to process completion and more roughness data be collected to identify a trend between hatch spacing and surface roughness.

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2018-05

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Bharatanatyam and its effect on Stress, Mood, and Anxiety

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Abstract
This study investigates the effects of Bharatanatyam dance on stress, mood, and anxiety. I have danced Bharatanatyam since I was 8 years old, it has offered me a way to release stress

Abstract
This study investigates the effects of Bharatanatyam dance on stress, mood, and anxiety. I have danced Bharatanatyam since I was 8 years old, it has offered me a way to release stress and anxiety. This study provides empirical data to support the claim that Bharatanatyam has therapeutic effects that release stress and reduce anxiety. This investigation was conducted through self-reports and interviews. A Positive Affect and Negative Affect Schedule (PANAS) scale was used to determine positive and negative effects. The average positive affect during the “dance weeks” (DW) was 46.6 and the average negative affect was 12.2. During the “no dance weeks” (NDW), the average positive effect was 23.7 and the average negative affect was 31. The participant’s interview PANAS results had an average positive effect of 39.8 and an average negative effect of 12.8. Analyzing the self-report journaling highlighted a more prevalent use of positive words during the DW and a more significant use of negative words during the NDW. The Bharatanatyam dancers who were probed to enter post-performance environment for an interview also used positive words to describe Bharatanatyam dancing. In conclusion, practicing Bharatanatyam had an overall positive effect on mood, and can reduce stress and anxiety.

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2019-05