Matching Items (1,198)
Description
Waste heat energy conversion remains an inviting subject for research, given the renewed emphasis on energy efficiency and carbon emissions reduction. Solid-state thermoelectric devices have been widely investigated, but their practical application remains challenging because of cost and the inability to fabricate them in geometries that are easily compatible with heat sources. An intriguing alternative to solid-state thermoelectric devices is thermogalvanic cells, which include a generally liquid electrolyte that permits the transport of ions. Thermogalvanic cells have long been known in the electrochemistry community, but have not received much attention from the thermal transport community. This is surprising given that their performance is highly dependent on controlling both thermal and mass (ionic) transport. This research will focus on a research project, which is an interdisciplinary collaboration between mechanical engineering (i.e. thermal transport) and chemistry, and is a largely experimental effort aimed at improving fundamental understanding of thermogalvanic systems. The first part will discuss how a simple utilization of natural convection within the cell doubles the maximum power output of the cell. In the second part of the research, some of the results from the previous part will be applied in a feasibility study of incorporating thermogalvanic waste heat recovery systems into automobiles. Finally, a new approach to enhance Seebeck coefficient by tuning the configurational entropy of a mixed-ligand complex formation of copper sulfate aqueous electrolytes will be presented. Ultimately, a summary of these results as well as possible future work that can be formed from these efforts is discussed.
ContributorsGunawan, Andrey (Author) / Phelan, Patrick E (Thesis advisor) / Buttry, Daniel A (Committee member) / Mujica, Vladimiro (Committee member) / Chan, Candace K. (Committee member) / Wang, Robert Y (Committee member) / Arizona State University (Publisher)
Created2015
Description
The rapid progress of solution-phase synthesis has led colloidal nanocrystals one of the most versatile nanoscale materials, provided opportunities to tailor material's properties, and boosted related technological innovations. Colloidal nanocrystal-based materials have been demonstrated success in a variety of applications, such as LEDs, electronics, solar cells and thermoelectrics. In each of these applications, the thermal transport property plays a big role. An undesirable temperature rise due to inefficient heat dissipation could lead to deleterious effects on devices' performance and lifetime. Hence, the first project is focused on investigating the thermal transport in colloidal nanocrystal solids. This study answers the question that how the molecular structure of nanocrystals affect the thermal transport, and provides insights for future device designs. In particular, PbS nanocrystals is used as a monitoring system, and the core diameter, ligand length and ligand binding group are systematically varied to study the corresponding effect on thermal transport.
Next, a fundamental study is presented on the phase stability and solid-liquid transformation of metallic (In, Sn and Bi) colloidal nanocrystals. Although the phase change of nanoparticles has been a long-standing research topic, the melting behavior of colloidal nanocrytstals is largely unexplored. In addition, this study is of practical importance to nanocrystal-based applications that operate at elevated temperatures. Embedding colloidal nanocrystals into thermally-stable polymer matrices allows preserving nanocrystal size throughout melt-freeze cycles, and therefore enabling observation of stable melting features. Size-dependent melting temperature, melting enthalpy and melting entropy have all been measured and discussed.
In the next two chapters, focus has been switched to developing colloidal nanocrystal-based phase change composites for thermal energy storage applications. In Chapter 4, a polymer matrix phase change nanocomposite has been created. In this composite, the melting temperature and energy density could be independently controlled by tuning nanocrystal diameter and volume fractions. In Chapter 5, a solution-phase synthesis on metal matrix-metal nanocrytal composite is presented. This approach enables excellent morphological control over nanocrystals and demonstrated a phase change composite with a thermal conductivity 2 - 3 orders of magnitude greater than typical phase change materials, such as organics and molten salts.
Next, a fundamental study is presented on the phase stability and solid-liquid transformation of metallic (In, Sn and Bi) colloidal nanocrystals. Although the phase change of nanoparticles has been a long-standing research topic, the melting behavior of colloidal nanocrytstals is largely unexplored. In addition, this study is of practical importance to nanocrystal-based applications that operate at elevated temperatures. Embedding colloidal nanocrystals into thermally-stable polymer matrices allows preserving nanocrystal size throughout melt-freeze cycles, and therefore enabling observation of stable melting features. Size-dependent melting temperature, melting enthalpy and melting entropy have all been measured and discussed.
In the next two chapters, focus has been switched to developing colloidal nanocrystal-based phase change composites for thermal energy storage applications. In Chapter 4, a polymer matrix phase change nanocomposite has been created. In this composite, the melting temperature and energy density could be independently controlled by tuning nanocrystal diameter and volume fractions. In Chapter 5, a solution-phase synthesis on metal matrix-metal nanocrytal composite is presented. This approach enables excellent morphological control over nanocrystals and demonstrated a phase change composite with a thermal conductivity 2 - 3 orders of magnitude greater than typical phase change materials, such as organics and molten salts.
ContributorsLiu, Minglu (Author) / Wang, Robert Y (Thesis advisor) / Wang, Liping (Committee member) / Rykaczewski, Konrad (Committee member) / Phelan, Patrick (Committee member) / Dai, Lenore (Committee member) / Arizona State University (Publisher)
Created2015
Description
Soft polymer composites with improved thermal conductivity are needed for the thermal management of electronics. Interfacial thermal boundary resistance, however, prevents the efficient use of many high thermal conductivity fill materials. Magnetic alignment of ferrous fill material enforces percolation of the high thermal conductivity fill, thereby shifting the governing boundary resistance to the particle- particle interfaces and increasing the directional thermal conductivity of the polymer composite. Magnetic alignment maximizes the thermal conductivity while minimizing composite stiffening at a fill fraction of half the maximum packing factor. The directional thermal conductivity of the composite is improved by more than 2-fold. Particle-particle contact engineering is then introduced to decrease the particle- particle boundary resistance and further improve the thermal conductivity of the composite.
The interface between rigid fill particles is a point contact with very little interfacial area connecting them. Silver and gallium-based liquid metal (LM) coatings provide soft interfaces that, under pressure, increase the interfacial area between particles and decrease the particle-particle boundary resistance. These engineered contacts are investigated both in and out of the polymer matrix and with and without magnetic alignment of the fill. Magnetically aligned in the polymer matrix, 350nm- thick silver coatings on nickel particles produce a 1.8-fold increase in composite thermal conductivity over the aligned bare-nickel composites. The LM coatings provide similar enhancements, but require higher volumes of LM to do so. This is due to the rapid formation of gallium oxide, which introduces additional thermal boundaries and decreases the benefit of the LM coatings.
The oxide shell of LM droplets (LMDs) can be ruptured using pressure. The pressure needed to rupture LMDs matches closely to thin-walled pressure vessel theory. Furthermore, the addition of tungsten particles stabilizes the mixture for use at higher pressures. Finally, thiols and hydrochloric acid weaken the oxide shell and boost the thermal performance of the beds of LMDs by 50% at pressures much lower than 1 megapascal (MPa) to make them more suitable for use in TIMs.
The interface between rigid fill particles is a point contact with very little interfacial area connecting them. Silver and gallium-based liquid metal (LM) coatings provide soft interfaces that, under pressure, increase the interfacial area between particles and decrease the particle-particle boundary resistance. These engineered contacts are investigated both in and out of the polymer matrix and with and without magnetic alignment of the fill. Magnetically aligned in the polymer matrix, 350nm- thick silver coatings on nickel particles produce a 1.8-fold increase in composite thermal conductivity over the aligned bare-nickel composites. The LM coatings provide similar enhancements, but require higher volumes of LM to do so. This is due to the rapid formation of gallium oxide, which introduces additional thermal boundaries and decreases the benefit of the LM coatings.
The oxide shell of LM droplets (LMDs) can be ruptured using pressure. The pressure needed to rupture LMDs matches closely to thin-walled pressure vessel theory. Furthermore, the addition of tungsten particles stabilizes the mixture for use at higher pressures. Finally, thiols and hydrochloric acid weaken the oxide shell and boost the thermal performance of the beds of LMDs by 50% at pressures much lower than 1 megapascal (MPa) to make them more suitable for use in TIMs.
ContributorsRalphs, Matthew (Author) / Rykaczewski, Konrad (Thesis advisor) / Wang, Robert Y (Thesis advisor) / Phelan, Patrick (Committee member) / Wang, Liping (Committee member) / Devasenathipathy, Shankar (Committee member) / Arizona State University (Publisher)
Created2019
Description
During the 1970's to 90's, scholars in the fields of Jewish Studies, anthropology and sociology (notably, Hellen Epstein, Larry Langer and Yosef Yerushalmi), developed the idea of generational trauma theory, when analyzing the trauma inflicted upon European Jewish populations during the Holocaust. Epstein argues that trauma is passed down from generation to generation, while Langer argues that the second generation interprets the trauma in their own way. Other important terms in trauma theory include liturgical time, sites of memory, historical trauma and the historical trauma response. Scholars who analyze American Indian communities, like Yellow Horse Brave Heart and Durran/Durran, readily took up this theory, applying it to the Native American experience. One area where this theory has been applied to is the Native American Boarding School experience. The purpose of this paper is to analyze the efficacy of applying the post-Holocaust trauma theory to the Native American boarding school experience. In order to determine the effectiveness of the boarding schools, one must analyze the boarding school experience, beginning at the philosophical underpinnings of the boarding school, and then discussing the impacts that the boarding schools had on the students and finally, the impact that this had on the second generation. However, this approach has a number of flaws, such as the differences between native communities and post-Holocaust, American, Jewish communities, as discussed in the Philosophy of American Indian Studies. The length of the boarding schools was also longer than the length of the Holocaust. The fact that Native Americans faced repeated trauma, in a way that post-Holocaust American Jews did not. The trauma also changed for both native peoples and post-Holocaust Jews, making it difficult for there to be a single response to trauma. The philosophical bases of the Holocaust and boarding schools were also different. The post-Holocaust generational trauma approach also has a number of applications to native peoples. This includes the psychological aspect of trauma. The use of terminology by native scholars. Native peoples also developed concepts like sites of memory and liturgical time. Finally, both the post-Holocaust Jewas and Native Americans have used trauma for political ends. The conclusion is that post-Holocaust generational trauma theory has some applications to native peoples, but the application is limited. A scholar must take into careful consideration the native peoples who they are working with.
ContributorsMongeau, Michael Philip (Author) / Benkert, Volker (Thesis director) / Riding In, James (Committee member) / School of Historical, Philosophical and Religious Studies (Contributor) / American Indian Studies Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Sigmund Freud's psychoanalytic theory proposes that the personality has three components, the id, superego, and ego. The id is concerned with pleasure and gain, the reason it is often identified as a human's animalistic side. Additionally, the id does not consider social rules as closely and is the uncensored portion of the personality. The superego is the id's opposite; the superego considers social expectations and pressures immensely, is more self-critical and moralizing. The ego mediates the id and superego, and is understood as the realistic expression of personality which considers both the "animal" and human. A Fractured Whole: A Collection of Short Stories, explores Freud's construction of human personality in both form and content. Within the collection are three sections, each with a different pair of characters. Within each section, the same scene is written in the three "modes" of the id, superego, and ego, as three separate stories. The fifteen stories comprising this collection address the substance of daily life: sexuality, body image, competition, among other topics, to consider how a single person can balance the desires for personal pleasure and to satisfy social expectations. Writing the same scene in three "modes" allows for the observation of how the characters attitudes and actions alter under the influence of different parts of their personalities.
ContributorsOtte, Aneka (Author) / Sturges, Robert (Thesis director) / Bryant, Jason (Committee member) / School of Historical, Philosophical and Religious Studies (Contributor) / Department of English (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Since Dylan Roof, a white supremacist, shot and killed nine members of a black church in Charleston on June 17, 2015, Confederate symbols have stood at the center of much controversy across the United States. Although the Confederate battle flag remains the most obvious example, the debate took a particular form in Tennessee, centering on the image of General Nathan Bedford Forrest. Born in 1822 to a poor family, he left school early to work. Although his work in the slave trade made him a millionaire, his later participation in the massacre of over 300 black soldiers at Fort Pillow in 1864 during the Civil War and association with the Ku Klux Klan cemented his reputation as a violent racist. Yet, many white Tennesseans praised him as a hero and memorialized him. This thesis examines Nathan Bedford Forrest State Park in Benton County and Forrest Park, now Health Sciences Park, in Memphis to examine what characteristics denote a controversial memorial. Specifically, I focus on the physical form, the location, and the demographics of the area, investigating how these components work together to give rise to controversy or acceptance of the memorial's image. Physical representations greatly impact the ideas associated with the memorial while racial demographics affect whether or not Forrest's representation as a hero speaks true to modern interpretations and opinions.
ContributorsFish, Caroline Rose (Author) / Longley, Rodney (Thesis director) / Suk, Mina (Committee member) / School of Historical, Philosophical and Religious Studies (Contributor) / School of Politics and Global Studies (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This thesis explores the intersection of religion, social class, and politics during the late nineteenth century in Imperial Germany. Specifically, the focus of this work is on the Workers' Association of Saint Paul's in Aachen and Burtscheid, a Catholic working-class organization in the 1870s located in the city of Aachen, a rapidly industrializing city in the majority Catholic Prussian Rhineland. This organization was the largest Catholic working-class association in Germany in the 1870s, reaching 5,000 members by the middle of the decade, and also espoused the politics of Christian Socialism. This thesis explores the intersection of the possibly competing social identities of these workers between being Catholics and workers. To start, the scholarly framework of studying society and politics in Imperial Germany is discussed, especially the concept of rigidly constructed social milieus into five groups, two of them being the Catholics and the working-class, and how this work may suggest a challenge to this concept. Next, the background information of how a Catholic working-class came into existence, as it was the product of simultaneous nineteenth century processes of industrialization and a religious revival among German Catholics. The Kulturkampf was the force that politicized Catholicism in Germany, as the persecution of Catholic institutions by Prussia forced Catholics into a social and political "ghetto." Then, the Association of St. Paul's itself is discussed. First, the workers espoused their Catholic identity and religious solidarity during a time of persecution, but also emphasized the Christian basis for their brand of Socialism. This lent into their identity as part of the working-class. While they steadfastly rejected the "godlessness" of Social Democracy, the Christian Socialists also shared many similar social and political goals. This intersection between identities eventually led to political conflict in Aachen throughout the 1870s with the mainstream, bourgeois Catholics of the city. To conclude, the legacy of Christian Socialism on modern Germany is discussed, as well as its contribution to the complex politics of Imperial Germany.
ContributorsHarkness, John Hosea (Author) / Benkert, Volker (Thesis director) / Holian, Anna (Committee member) / School of Politics and Global Studies (Contributor) / School of International Letters and Cultures (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Abstract. The term "sex trafficking" can mean many different things, depending on who uses it. To some, it may be synonymous with prostitution. To others, it may equate to slavery. And some may find that sex trafficking differs from both slavery and prostitution. But I find that the term "sex trafficking" is used improperly when referring to phenomena that may not entail the violation of rights of any individual involved. For this reason, various definitions of "sex trafficking" may inappropriately conflate sex trafficking with prostitution. In this essay, I argue against such a conflation through supporting a rights-based approach of defining "sex trafficking," in which every instance of true sex trafficking necessitates a violation of someone's rights. First, I begin by laying the foundation of my discussion with definitions and various government and non-government uses of the term "sex trafficking." Then, I argue for the rights-based approach. I proceed to explore how the rights-based approach relates to consent, force, coercion, deception, and competence. Then, I compile my findings, synthesize a definition, and elaborate on a few questions regarding my definition. Using the term "sex trafficking" correctly, as I argue, means that we necessarily use the term in a context of a violation of rights.
ContributorsMiller, Isaac Jonathan (Author) / de Marneffe, Peter (Thesis director) / McGregor, Joan (Committee member) / School of Historical, Philosophical and Religious Studies (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Popular Culture of today, particularly books and movies have begun to influence the way individ- uals and society as a whole, views specific concepts. In this case, the fairly recent phenomenon of the Sci- ence Fiction Drug Niche has produced significant thought among audiences as to both the benefits and costs of cognitive enhancers in our world. Through the use of both a thorough analysis of modern films and novels on the topic as well as focus groups of the average college students this study analyzes the influence that this niche has had on the perceptions that students have towards the use of such cognitive enhancements. Small groups of students were shown the same film: Limitless, and discussion after the film displayed the students thoughts and attitudes towards the ideas shown in the film. Limitless itself falls into this Science Fiction drug niche and discusses both benefits and harms of chemical cognitive enhancement. The study indicates that audiences have thought not only about the issues that may arise with the presence of cognitive enhancement in our world but also the possible benefits of this enhancement. The results go even further to preliminarily show that there are common thoughts that arise in such situations. These common ideas that arise show, at least on a very basic level, that the presence of these Science Fiction Drug-inspired works are influencing the way audiences perceive the use of cognitive enhancement as well as influencing what doubts, questions, hopes, and fears arise from these pharmaceuticals. This preliminary study could use further research to ana- lyze the effects of popular culture on perceptions of cognitive enhancement and pharmaceuticals to alter consciousness.
ContributorsSyed, Mariha Batool (Author) / Zachary, Gregg (Thesis director) / Hurlbut, Ben (Committee member) / School of Historical, Philosophical and Religious Studies (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Since the passage of the Federal Election Campaign Act Amendments of 1974 (FECA) up until the most recent election in 2012, presidential campaign funds have risen over five hundred percent. While money has always been an essential and critical part of any political campaign, this rise has been drastic and continues to increase at a higher rate with every election cycle, even when the numbers are adjusted for inflation. The purpose of this paper is to examine this continuous increase in cost of presidential campaigns and to analyze the different pieces that have contributed to this rise. The main pieces include two Supreme Court cases: Buckley v. Valeo and Citizens United v. Federal Elections Commission, the rise and fall of federally regulated public funding and the various pieces of a presidential campaign that have considerably higher ticket prices with each election cycle. This paper first goes through both Buckley and Citizens, describing what each Supreme Court decision did and how they effected how much money can be spent in a presidential campaign and by whom. The paper then examines each presidential election since the passage of FECA in 1974 through the last election with President Barack Obama and Mitt Romney in 2012. Each election cycle is broken down to show how much money was spent by each candidate and the Republican and Democratic National Committees, whether or not the money was received through public funds or raised privately, and subsequently the percentages of where the money was spent. While the examination of the Court cases helps to understand why so much money can be donated and contributed directly to campaigns or spent on behalf of a presidential candidate, the breakdown of where the money is spent including advertising, travel, staff salaries etc. helps to show why a presidential campaign costs over five hundred percent more today than it did forty years ago. By understanding this increase, how it was caused and where the money is going, it is more feasible to comprehend whether or not campaign finance reform should be proposed and if so, how it should be brought about.
ContributorsColby, Mikaela Nicole (Author) / Critchlow, Donald (Thesis director) / Shair-Rosenfield, Sarah (Committee member) / School of Historical, Philosophical and Religious Studies (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05