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- Creators: Arizona State University
Description
Emergent environmental issues, ever-shrinking petroleum reserves, and rising fossil fuel costs continue to spur interest in the development of sustainable biofuels from renewable feed-stocks. Meanwhile, however, the development and viability of biofuel fermentations remain limited by numerous factors such as feedback inhibition and inefficient and generally energy intensive product recovery processes. To circumvent both feedback inhibition and recovery issues, researchers have turned their attention to incorporating energy efficient separation techniques such as adsorption in in situ product recovery (ISPR) approaches. This thesis focused on the characterization of two novel adsorbents for the recovery of alcohol biofuels from model aqueous solutions. First, a hydrophobic silica aerogel was evaluated as a biofuel adsorbent through characterization of equilibrium behavior for conventional second generation biofuels (e.g., ethanol and n-butanol). Longer chain and accordingly more hydrophobic alcohols (i.e., n-butanol and 2-pentanol) were more effectively adsorbed than shorter chain alcohols (i.e., ethanol and i-propanol), suggesting a mechanism of hydrophobic adsorption. Still, the adsorbed alcohol capacity at biologically relevant conditions were low relative to other `model' biofuel adsorbents as a result of poor interfacial contact between the aqueous and sorbent. However, sorbent wettability and adsorption is greatly enhanced at high concentrations of alcohol in the aqueous. Consequently, the sorbent exhibits Type IV adsorption isotherms for all biofuels studied, which results from significant multilayer adsorption at elevated alcohol concentrations in the aqueous. Additionally, sorbent wettability significantly affects the dynamic binding efficiency within a packed adsorption column. Second, mesoporous carbons were evaluated as biofuel adsorbents through characterization of equilibrium and kinetic behavior. Variations in synthetic conditions enabled tuning of specific surface area and pore morphology of adsorbents. The adsorbed alcohol capacity increased with elevated specific surface area of the adsorbents. While their adsorption capacity is comparable to polymeric adsorbents of similar surface area, pore morphology and structure of mesoporous carbons greatly influenced adsorption rates. Multiple cycles of adsorbent regeneration rendered no impact on adsorption equilibrium or kinetics. The high chemical and thermal stability of mesoporous carbons provide potential significant advantages over other commonly examined biofuel adsorbents. Correspondingly, mesoporous carbons should be further studied for biofuel ISPR applications.
ContributorsLevario, Thomas (Author) / Nielsen, David R (Thesis advisor) / Vogt, Bryan D (Committee member) / Lind, Mary L (Committee member) / Arizona State University (Publisher)
Created2011
Description
Virtue was a concept of paramount importance in the American founders' republican thought. Without virtue, there could be no liberty, no order, no devotion to the common good, and no republican government. This dissertation examines the concept of virtue at the American founding, particularly virtue in the political thought of Mercy Otis Warren (1728-1814). The most important female intellectual of the Revolutionary generation, Warren wrote passionately about liberty and the beauty of republican ideals. Most important to this study, she consistently advocated the central place of virtue in a free and well-ordered republic. I argue that Warren incorporates three distinct philosophical threads - classical, bourgeois-marketplace, and Christian ideals - in her conception of virtue. I first analyze how Warren uses each of these three threads of virtue throughout her writings. I then examine how she synthesizes these individual threads into a single, cohesive conception of virtue. I argue that Warren consistently merges these ideals into a conception of virtue that she employs to address three pressing political problems of her day: How to motivate reluctant colonists to seek independence; how to check various forms of corruption spreading among the people; and how to counter corruption arising from commercial growth in the new nation. Modern political theorists often argue that these three threads, especially the classical republican and Christian ideals of virtue, are irreconcilable. My analysis shows that to divorce virtue from Christianity in Warren's conception is to rob it of its corrective vigor within republican government. I argue that what Machiavelli and Rousseau wrote out of republican virtue Warren writes back in. In Warren's political thought, virtue serves as the foundation for a stable enduring political system, provides the necessary informal ordering principle for the emerging republic, and offers the means by which the new nation could achieve its millennial destiny.
ContributorsMunsil, Tracy F (Author) / Ball, Terence (Thesis advisor) / Dagger, Richard (Thesis advisor) / Crittenden, William J. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Historians often characterize first ladies in the Progressive Era as representatives of the last vestiges of Victorian womanhood in an increasingly modern society. This dissertation argues that first ladies negotiated an image of themselves that fulfilled both traditional and modern notions of womanhood. In crafting these images, first ladies constructed images of their celebrity selves that were uniquely modern. Thus, images of first ladies in the Progressive Era show them as modest and feminine but also autonomous, intelligent, and capable. Using the historian Charles Ponce de Leon's research on modern human-interest journalism, I contend that first ladies in the Progressive Era worked with the modern press in a symbiotic relationship. This relationship allowed the press exclusive access to what was, ostensibly, the first lady's private, and therefore authentic, self. By purporting to reveal parts of their private lives in the press, first ladies showed themselves as down-to-earth despite their success and fulfilled by their domestic pursuits despite their compelling public lives. By offering the press exclusive access to their lives, first ladies secured the opportunity to shape specific images of themselves to appeal, as broadly as possible, to their husbands and parties' constituents and the American public. First ladies in the Progressive Era thus acted as political figures by using both public and private, or what historian Catherine Allgor terms, "unofficial spaces" to support and reflect their husbands and parties' political agendas. In examining representations of first ladies in popular magazines and newspapers from 1901 to 1921 in tandem with letters, memoirs, and other personal papers from these women, a clear pattern emerges. Despite personal differences, first ladies in the Progressive Era represented themselves according to a specific formula in the modern press. The images, constructed by first ladies in this time period, reflect shifts in economic, social, and political life in Progressive Era America, which called for women to be independent and intelligent yet still maintain their femininity and domesticity.
ContributorsHorohoe, Jill (Author) / Gullett, Gayle (Thesis advisor) / Longley, Rodney K (Committee member) / Warren-Findley, Jannelle (Committee member) / Arizona State University (Publisher)
Created2011
Description
Proton exchange membrane fuel cells (PEMFCs) run on pure hydrogen and oxygen (or air), producing electricity, water, and some heat. This makes PEMFC an attractive option for clean power generation. PEMFCs also operate at low temperature which makes them quick to start up and easy to handle. PEMFCs have several important limitations which must be overcome before commercial viability can be achieved. Active areas of research into making them commercially viable include reducing the cost, size and weight of fuel cells while also increasing their durability and performance. A growing and important part of this research involves the computer modeling of fuel cells. High quality computer modeling and simulation of fuel cells can help speed up the discovery of optimized fuel cell components. Computer modeling can also help improve fundamental understanding of the mechanisms and reactions that take place within the fuel cell. The work presented in this thesis describes a procedure for utilizing computer modeling to create high quality fuel cell simulations using Ansys Fluent 12.1. Methods for creating computer aided design (CAD) models of fuel cells are discussed. Detailed simulation parameters are described and emphasis is placed on establishing convergence criteria which are essential for producing consistent results. A mesh sensitivity study of the catalyst and membrane layers is presented showing the importance of adhering to strictly defined convergence criteria. A study of iteration sensitivity of the simulation at low and high current densities is performed which demonstrates the variance in the rate of convergence and the absolute difference between solution values derived at low numbers of iterations and high numbers of iterations.
ContributorsArvay, Adam (Author) / Madakannan, Arunachalanadar (Thesis advisor) / Peng, Xihong (Committee member) / Liang, Yong (Committee member) / Subach, James (Committee member) / Arizona State University (Publisher)
Created2011
Description
The following dissertation provides perspectives on the social, political, economic, and academic influences on language use, and particularly heritage language use, within the Filipino American community. What is the nature of language in this community? In what ways does language exist or co-exist? The hypothesis that autochthonous Filipino languages in the United States cease to be spoken in favor of English by Filipino Americans was tested through mixed methods of research. Literature and databases were reviewed which provided information concerning statistics, issues, and policies relating to language in Filipino America. Field research and interviews were conducted in which language use was of key interest. Results varied individually and contextually. Language seems to exist within the Filipino American community on a dynamic continuum. Immigrant Filipino Americans appear to be bilingual and multilingual. Second generation Filipino Americans tend to be English dominant with a range of bilingualism. The California Department of Education (CDOE) appears to foster bilingualism / multilingualism through its World Languages Departments (secondary education level), by offering language courses, such as Tagalog-based Filipino. Efforts to maintain non-English, Filipino languages in Arizona are less conspicuous, but they do exist primarily in familial and entrepreneurial ways.
ContributorsAxel, Joseph (Author) / Mccarty, Teresa (Thesis advisor) / Wiley, Terrence (Committee member) / Faltis, Christian (Committee member) / Arizona State University (Publisher)
Created2011
Description
Since the 1988 uprising, a transnational advocacy network has formed around the issue of democracy and human rights in Burma. Within this transnational advocacy network, personal narratives of trauma have been promulgated in both international and oppositional news media and human rights reports. My thesis critically analyzes the use of the trauma narrative for advocacy purposes by the transnational advocacy network that has emerged around Burma and reveals the degree to which these narratives adhere to a Western, individualistic meta-narrative focused on political and civil liberties. Examining the "boomerang" pattern and the concept of marketability of movements, I highlight the characteristics of the 1988 uprising and subsequent opposition movement that attracted international interest. Reflecting on the psychological aspects of constructing trauma narratives, I then review the scholarship which links trauma narratives to social and human rights movements. Using a Foucauldian approach to discourse analysis, I subsequently explain my methodology in analyzing the personal narratives I have chosen. Beyond a theoretical discussion of trauma narratives and transnational advocacy networks, I analyze the use of personal narratives of activists involved in the 1988 uprising and the emergence of Aung San Suu Kyi's life story as a compelling narrative for Western audiences. I then explore the structure of human rights reports which situate personal narratives of trauma within the framework of international human rights law. I note the differences in the construction of traumatic narratives of agency and those of victimization. Finally, using Cyclone Nargis as a case study, I uncover the discursive divide between human rights and humanitarian actors and their use of personal narratives to support different discursive constructions of the aid effort in the aftermath of the cyclone. I conclude with an appeal to a more reflexive approach to advocacy work reliant on trauma narratives and highlight feminist methodologies that have been successful in bringing marginalized narratives to the center of human rights discussions.
ContributorsBynum, Kate Elliott (Author) / Stancliff, Michael (Thesis advisor) / Friedrich, Patricia (Committee member) / Vaughan, Suzanne (Committee member) / Arizona State University (Publisher)
Created2011
Description
Infant mortality rate of field deployed photovoltaic (PV) modules may be expected to be higher than that estimated by standard qualification tests. The reason for increased failure rates may be attributed to the high system voltages. High voltages (HV) in grid connected modules induce additional stress factors that cause new degradation mechanisms. These new degradation mechanisms are not recognized by qualification stress tests. To study and model the effect of high system voltages, recently, potential induced degradation (PID) test method has been introduced. Using PID studies, it has been reported that high voltage failure rates are essentially due to increased leakage currents from active semiconducting layer to the grounded module frame, through encapsulant and/or glass. This project involved designing and commissioning of a new PID test bed at Photovoltaic Reliability Laboratory (PRL) of Arizona State University (ASU) to study the mechanisms of HV induced degradation. In this study, PID stress tests have been performed on accelerated stress modules, in addition to fresh modules of crystalline silicon technology. Accelerated stressing includes thermal cycling (TC200 cycles) and damp heat (1000 hours) tests as per IEC 61215. Failure rates in field deployed modules that are exposed to long term weather conditions are better simulated by conducting HV tests on prior accelerated stress tested modules. The PID testing was performed in 3 phases on a set of 5 mono crystalline silicon modules. In Phase-I of PID test, a positive bias of +600 V was applied, between shorted leads and frame of each module, on 3 modules with conducting carbon coating on glass superstrate. The 3 module set was comprised of: 1 fresh control, TC200 and DH1000. The PID test was conducted in an environmental chamber by stressing the modules at 85°C, for 35 hours with an intermittent evaluation for Arrhenius effects. In the Phase-II, a negative bias of -600 V was applied on a set of 3 modules in the chamber as defined above. The 3 module set in phase-II was comprised of: control module from phase-I, TC200 and DH1000. In the Phase-III, the same set of 3 modules which were used in the phase-II again subjected to +600 V bias to observe the recovery of lost power during the Phase-II. Electrical performance, infrared (IR) and electroluminescence (EL) were done prior and post PID testing. It was observed that high voltage positive bias in the first phase resulted in little
o power loss, high voltage negative bias in the second phase caused significant power loss and the high voltage positive bias in the third phase resulted in major recovery of lost power.
o power loss, high voltage negative bias in the second phase caused significant power loss and the high voltage positive bias in the third phase resulted in major recovery of lost power.
ContributorsGoranti, Sandhya (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Rogers, Bradley (Committee member) / Macia, Narciso (Committee member) / Arizona State University (Publisher)
Created2011
Description
Africa is misrepresented and mis-imaged in the western media. Because of this, notions and beliefs about atrocities that take place on the continent lack context, leaving people to think that Africa is a place of misery, darkness and despair; a monolithic land where evil resides. The image of Africa as the "heart of darkness" was conjured following the Joseph Conrad novel and the idea of Africa as the "Dark Continent" still pervades Western thought. This is an inadequate understanding of Africa, and lacks the context to comprehend why many of the atrocities in Africa occur. I will explore two atrocities in Africa, the 1994 Rwanda Genocide and child slavery on Lake Volta in Ghana. I believe that both these examples reflect how the label of evil is insufficient to describe the circumstances around each atrocity. In order to understand such events we must understand the part that colonialism and poverty play in the disruption of pan-African culture. The "evils" of these two phenomenon, are in many cases the result of the Western world's past involvement in Africa and are remnants and extensions of the disruption caused.
ContributorsBork, Paul (Author) / Simmons, William P (Thesis advisor) / Erfani, Julie (Committee member) / Anokye, Duku A (Committee member) / Arizona State University (Publisher)
Created2011
Description
One in six children in the developing world is engaged in Child labor. Child labor is considered an issue that violates children's rights in many countries and Iraq is no exception. In 2004, Iraq had 1,300,000 children between the ages of eight and sixteen years engaged in work (UNICEF.com, 2004). This study identifies the major causes of child labor in Iraq and investigates the consequences of this issue. In this thesis I draw on the comparison of former regimes in Iraq and Egypt and how those regimes were mistreating their citizens by making them live under poverty and oppression while they were receiving support from the U.S. Poverty is the major cause behind Iraqi children engaging in work. I used the data I collected in Iraq, in the city of Nasiriyah, of 28 working children to explain the relationship between poverty, students drop out of school, family attitude towards education and the child engagement in work. At the end of the thesis I offer a list of recommendations to try to address the problem of child labor in Iraq. The recommendations and regulations are for Iraqi government and the NGOs to take into consideration in trying to resolve and regulate the issue of child labor to rescue the children in Iraq from more exploitation in the future.
ContributorsAl-Taee, Hawraa F (Author) / Elenes, C (Thesis advisor) / Erfani, Julie M (Committee member) / Ali, Souad (Committee member) / Arizona State University (Publisher)
Created2011
Description
Building Applied Photovoltaics (BAPV) form an essential part of today's solar economy. This thesis is an effort to compare and understand the effect of fan cooling on the temperature of rooftop photovoltaic (PV) modules by comparing two side-by-side arrays (test array and control array) under identical ambient conditions of irradiance, air temperature, wind speed and wind direction. The lower operating temperature of PV modules due to fan operation mitigates array non uniformity and improves on performance. A crystalline silicon (c-Si) PV module has a light to electrical conversion efficiency of 14-20%. So on a cool sunny day with incident solar irradiance of 1000 W/m2, a PV module with 15% efficiency, will produce about only 150 watts. The rest of the energy is primarily lost in the form of heat. Heat extraction methods for BAPV systems may become increasingly higher in demand as the hot stagnant air underneath the array can be extracted to improve the array efficiency and the extracted low-temperature heat can also be used for residential space heating and water heating. Poly c-Si modules experience a negative temperature coefficient of power at about -0.5% /o C. A typical poly c-Si module would experience power loss due to elevation in temperature, which may be in the range of 25 to 30% for desert conditions such as that of Mesa, Arizona. This thesis investigates the effect of fan cooling on the previously developed thermal models at Arizona State University and on the performance of PV modules/arrays. Ambient conditions are continuously monitored and collected to calculate module temperature using the thermal model and to compare with actually measured temperature of individual modules. Including baseline analysis, the thesis has also looked into the effect of fan on the test array in three stages of 14 continuous days each. Multiple Thermal models are developed in order to identify the effect of fan cooling on performance and temperature uniformity. Although the fan did not prove to have much significant cooling effect on the system, but when combined with wind blocks it helped improve the thermal mismatch both under low and high wind speed conditions.
ContributorsChatterjee, Saurabh (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Rogers, Bradley (Committee member) / Macia, Narciso (Committee member) / Arizona State University (Publisher)
Created2011