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- Language: English
- Creators: Ira A. Fulton Schools of Engineering
Description
The flexural behavior of epoxies was investigated by performing mechanical tests and applying statistical Weibull theory and analytical methods to the results. The effects of loading systems and environmental conditions were also considered. Three kinds of epoxies were studied: Epon E863, PRI 2002, and PR520. In total, 53 three-point-bending (3PB) Epon E863 samples and 26 3PB PR520 were tested immediately after curing, together with 26 four-point-bending (4PB) PRI2002 samples stored at 60°C and 90% Rh for 48 weeks. The Weibull parameters were estimated using both linear regression and the moments method. The statistical character of the Weibull model leads to uncertainty in the evaluated parameters, even for a large number of experiments. This study analyzed the ratio of flexural strength to tensile strength in bulk epoxy resin polymers. An analytical method previously developed by the authors to study the relationship between uniaxial tension/compression stress-strain curves and flexural load-deflection response was used to obtain the ratio. The results show that the Weibull model overpredicted the aforementioned ratio in different load arrangements.
ContributorsYekani Fard, Masoud (Author) / Raji, B. (Author) / Chattopadhyay, Aditi (Author) / Ira A. Fulton Schools of Engineering (Contributor) / School for the Engineering of Matter, Transport and Energy (Contributor)
Created2014-12-01
Description
Identification of early damage in polymer composites is of great importance. We have incorporated cyclobutane-containing cross-linked polymers into an epoxy matrix, studied the effect on thermal and mechanical properties, and, more importantly, demonstrated early damage detection through mechanically induced fluorescence generation. Two cinnamate derivatives, 1,1,1-tris(cinnamoyloxymethyl) ethane (TCE) and poly(vinyl cinnamate) (PVCi), were photoirradiated to produce cyclobutane-containing polymer. The effects on the thermal and mechanical properties with the addition of cyclobutane-containing polymer into epoxy matrix were investigated. The emergence of cracks was detected by fluorescence at a strain level just beyond the yield point of the polymer blends, and the fluorescence intensified with accumulation of strain. Overall, the results show that damage can be detected through fluorescence generation along crack propagation.
ContributorsZou, Jin (Author) / Liu, Yingtao (Author) / Shan, Bohan (Author) / Chattopadhyay, Aditi (Author) / Dai, Lenore (Author) / Ira A. Fulton Schools of Engineering (Contributor) / School for the Engineering of Matter, Transport and Energy (Contributor)
Created2014-09-01
Description
The impact of increasing penetration of converter control-based generators (CCBGs) in a large-scale power system is assessed through a model based small signal stability analysis. Three test bed cases for the years 2010, 2020, and 2022 of the Western Electricity Coordinating Council (WECC) in the United States are used for the analysis. Increasing penetration of wind-based Type 3 and wind-based Type 4 and PV Solar CCBGs is used in the tests. The participation and interaction of CCBGs and synchronous generators in traditional electromechanical interarea modes is analyzed. Two new types of modes dominated by CCBGs are identified. The characteristics of these new modes are described and compared to electromechanical modes in the frequency domain. An examination of the mechanism of the interaction between the CCBG control states and the synchronous generator control states is presented and validated through dynamic simulations. Actual system and forecast load data are used throughout.
ContributorsQuintero, Jaime (Author) / Vittal, Vijay (Author) / Heydt, Gerald (Author) / Zhang, Hui (Author) / Ira A. Fulton Schools of Engineering (Contributor) / School of Electrical, Computer and Energy Engineering (Contributor)
Created2014-09-01
Description
The Physics and Chemistry of Surfaces and Interfaces conference has maintained a focus on the interfacial and surface properties of materials since its initiation in 1974. The conference continues to be a major force in this field, bringing together scientists from a variety of disciplines to focus upon the science of interfaces and surfaces. Here, a historical view of the development of the conference and a discussion of some of the themes that have been focal points for many years are presented.
ContributorsFerry, David (Author) / Ira A. Fulton Schools of Engineering (Contributor) / School of Electrical, Computer and Energy Engineering (Contributor)
Created2013
Description
The main purpose of this investigation is to determine the intensity, economic costs, and potential solutions to HIV/AIDS stigma in the United States and Tanzania. In order to accomplish this goal, a literature review was conducted, and an economic model was created to determine how HIV/AIDS treatment deterrence manifests and affects these countries. The results of the economic model suggested that Tanzania suffers greater economic loss due to HIV treatment deterrence than the United States, however, both countries lose a significant portion of GDP due to HIV treatment deterrence. Stigma materializes differently in each country based on a variety of sociocultural factors. These include the demographic groups most affected, the perception of those living with HIV, and how sexually transmitted infections are perceived within communities. The solutions to HIV stigma must be tailored to the country, culture, and context that it arises for interventions to be effective. To further prevent HIV/AIDS stigma and its economic consequences, the etiology of stigma and how it presents in different communities must be understood.
ContributorsSangha, Pooja (Co-author) / Hopewell, Sophia (Co-author) / Baldwin, Marjorie (Thesis director) / Hruschka, Daniel (Committee member) / Department of Psychology (Contributor) / Department of Economics (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
This paper explores the impacts of dam-induced displacement on the health of populations. By the start of the 21st century, an estimated 40-80 million people worldwide were forced to resettle due to the construction of large dams. The process of displacement and resettlement is connected to numerous social impacts on communities such as decreases in household income, natural resources, and social connectivity, but less seems to be known about specific health impacts. Analyzing literature in a formal review allowed for increased understanding about what information already exists in published research regarding the connections between dams, displacement, and health. Some negative health impacts as a result of forced displacement were identified, including increases in infectious disease transmission, depression, and mortality rates as well as losses of food and water sources. However, the small amount of cases found in the literature review when compared to the massive scale of dam development worldwide indicates a gap in knowledge in the dam industry and research field specifically about the health of the vast majority of populations forcibly displaced by dams. Health impacts must be considered and systematically studied in dam projects involving displacement to fully understand the needs of resettled populations and move towards equitable processes in development projects worldwide.
ContributorsWalker, Erika (Author) / Hruschka, Daniel (Thesis director) / Brian, Jennifer (Committee member) / Drake, Alexandria (Committee member) / School of Human Evolution & Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
In Western medicine, the hard sciences have generally been understood as the sole guiding force in patient care and treatment. However, both history and the present day suggest another strong influence on Western medicine: folklore. The term folklore can easily be dismissed as a term representing beliefs and stories of the past, but its relevance transcends time and continues to impact people daily. It “involves values, traditions, ways of thinking and behaving. It’s about art. It’s about people and the way people learn. It helps us learn who we are and how to make meaning in the world around us” (Sims & Stephens, 2011, pp. 1-2). With its wide range of influence, folklore exists as the umbrella term encompassing several categories. Folk beliefs are one of these categories and can develop from “observation, memory, testimony or inference” (Hutton, 1942, p. 83). Given that each of these forms are subject to some sort of error, folk beliefs become “a jumble of the true and the erroneous” (p. 84). Similarly, contemporary legends are narratives that often combine the physical and supernatural world to explain nuances or uncertainty present in the relevant experiences of a people. Folk beliefs can result in the formation of contemporary legends and they can also stem from contemporary legends. These two categories are often associated with subjects that promote fear and uncertainty, and thus play an essential role in navigating folklore’s application to biomedicine. This paper explores the historical and modern effects that folklore has had on two separate maladies: Hansen’s Disease (leprosy) and Major Depressive Disorder (depression). While these conditions do not resemble each other in physical presentations, Hansen’s Disease and Major Depressive Disorder patients both have faced and continue to face discrimination. Andrea Wiley and John Allen’s three-part definition of a malady: society’s perception (sickness), the individual’s experience (illness), and medical professionals’ diagnosis and treatment (disease); was utilized as a tool for analyzing the application of folklore to modern medicine. The way that a society views a particular malady often dictates the sick role expected of a diagnosed individual. Additionally, the public’s view can directly affect medical professionals’ understanding of a malady. This then can drastically shape a patient’s diagnosis, treatment, and prognosis. This anthropological analysis acts as an interdisciplinary bridge between medicine and the humanities.
ContributorsPeake, Ashley E (Co-author) / Peake, Ashley (Co-author) / Ellis, Lawrence (Thesis director) / Hoyt, Heather (Committee member) / Hruschka, Daniel (Committee member) / School of Molecular Sciences (Contributor) / Department of English (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Menstruation - a stigmatized topic and a social taboo- has led to a lack of menstrual hygiene awareness and improper practices impacting women’s health adversely over generations in India. Akshara aims to increase menstrual hygiene education and reduce stigma in India. A creative children’s illustrated book, and interactive workshop curriculum about menstruation were designed and published in Hindi and English. Menstrual hygiene workshops, utilizing the designed tools, were conducted in Delhi and Ghaziabad, India to over 230 students through NGO partnerships in December 2018. The response to the menstrual hygiene and stigma workshops was overwhelmingly positive, and a significant increase in the knowledge and awareness survey scores was observed after the curriculum teachings and classroom discussions. This evaluation highlights and provides a potential solution path to eradicate the root cause of the menstruation stigma in underprivileged women through education and open conversations on the topic starting at a pivotal young age. The main aim of the workshop was to help eradicate the stigma associated with menstruation and menstrual health in India through education.
ContributorsBhalla, Jahnavi (Co-author) / Dani, Advika (Co-author) / Schuster, Roseanne (Thesis director) / Hruschka, Daniel (Thesis director) / School of Molecular Sciences (Contributor) / School of Human Evolution & Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
More than 40% of all U.S. opioid overdose deaths in 2016 involved a prescription opioid, with more than 46 people dying every day from overdoses involving prescription opioids, (CDC, 2017). Over the years, lawmakers have implemented policies and laws to address the opioid epidemic, and many of these vary from state to state. This study will lay out the basic guidelines of common pieces of legislation. It also examines relationships between 6 state-specific prescribing or preventative laws and associated changes in opioid-related deaths using a longitudinal cross-state study design (2007-2015). Specifically, it uses a linear regression to examine changes in state-specific rates of opioid-related deaths after implementation of specific policies, and whether states implementing these policies saw smaller increases than states without these policies. Initial key findings of this study show that three policies have a statistically significant association with opioid related overdose deaths are—Good Samaritan Laws, Standing Order Laws, and Naloxone Liability Laws. Paradoxically, all three policies correlated with an increase in opioid overdose deaths between 2007 and 2016. However, after correcting for the potential spurious relationship between state-specific timing of policy implementation and death rates, two policies have a statistically significant association (alpha <0.05) with opioid overdose death rates. First, the Naloxone Liability Laws were significantly associated with changes in opioid-related deaths and was correlated with a 0.33 log increase in opioid overdose death rates, or a 29% increase. This equates to about 1.39 more deaths per year per 100,000 people. Second, the legislation that allows for 3rd Party Naloxone prescriptions correlated with a 0.33 log decrease in opioid overdose death rates, or a 29% decrease. This equates to 1.39 fewer deaths per year per 100,000 people.
ContributorsDavis, Joshua Alan (Author) / Hruschka, Daniel (Thesis director) / Gaughan, Monica (Committee member) / School of Human Evolution & Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Learning Sparse Representations for Fruit-Fly Gene Expression Pattern Image Annotation and Retrieval
Description
Background
Fruit fly embryogenesis is one of the best understood animal development systems, and the spatiotemporal gene expression dynamics in this process are captured by digital images. Analysis of these high-throughput images will provide novel insights into the functions, interactions, and networks of animal genes governing development. To facilitate comparative analysis, web-based interfaces have been developed to conduct image retrieval based on body part keywords and images. Currently, the keyword annotation of spatiotemporal gene expression patterns is conducted manually. However, this manual practice does not scale with the continuously expanding collection of images. In addition, existing image retrieval systems based on the expression patterns may be made more accurate using keywords.
Results
In this article, we adapt advanced data mining and computer vision techniques to address the key challenges in annotating and retrieving fruit fly gene expression pattern images. To boost the performance of image annotation and retrieval, we propose representations integrating spatial information and sparse features, overcoming the limitations of prior schemes.
Conclusions
We perform systematic experimental studies to evaluate the proposed schemes in comparison with current methods. Experimental results indicate that the integration of spatial information and sparse features lead to consistent performance improvement in image annotation, while for the task of retrieval, sparse features alone yields better results.
Fruit fly embryogenesis is one of the best understood animal development systems, and the spatiotemporal gene expression dynamics in this process are captured by digital images. Analysis of these high-throughput images will provide novel insights into the functions, interactions, and networks of animal genes governing development. To facilitate comparative analysis, web-based interfaces have been developed to conduct image retrieval based on body part keywords and images. Currently, the keyword annotation of spatiotemporal gene expression patterns is conducted manually. However, this manual practice does not scale with the continuously expanding collection of images. In addition, existing image retrieval systems based on the expression patterns may be made more accurate using keywords.
Results
In this article, we adapt advanced data mining and computer vision techniques to address the key challenges in annotating and retrieving fruit fly gene expression pattern images. To boost the performance of image annotation and retrieval, we propose representations integrating spatial information and sparse features, overcoming the limitations of prior schemes.
Conclusions
We perform systematic experimental studies to evaluate the proposed schemes in comparison with current methods. Experimental results indicate that the integration of spatial information and sparse features lead to consistent performance improvement in image annotation, while for the task of retrieval, sparse features alone yields better results.
ContributorsYuan, Lei (Author) / Woodard, Alexander (Author) / Ji, Shuiwang (Author) / Jiang, Yuan (Author) / Zhou, Zhi-Hua (Author) / Kumar, Sudhir (Author) / Ye, Jieping (Author) / Biodesign Institute (Contributor) / Center for Evolution and Medicine (Contributor) / Ira A. Fulton Schools of Engineering (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor)
Created2012-05-23