Matching Items (43,917)
Description
Ordered mesoporous materials have tunable pore sizes between 2 and 50 nm and are characterized by ordered pore structures and high surface areas (~1000 m2/g). This makes them particularly favorable for a number of membrane applications such as protein separation, polymer extrusion, nanowire fabrication and membrane reactors. These membranes can be fabricated as top-layers on macroporous supports or as embedded membranes in a dense matrix. The first part of the work deals with the hydrothermal synthesis and water-vapor/oxygen separation properties of supported MCM-48 and a new Al-MCM-48 type membrane for potential use in air conditioning systems. Knudsen-type permeation is observed in these membranes. The combined effect of capillary condensation and the aluminosilicate matrix resulted in the highest separation factor (142) in Al-MCM-48 membranes, with a water vapor permeance of 6×10-8mol/m2Pas. The second part focuses on synthesis of embedded mesoporous silica membranes with helically ordered pores by a novel Counter Diffusion Self-Assembly (CDSA) method. This method is an extension of the interfacial synthesis method for fiber synthesis using tetrabutylorthosilicate (TBOS) and cetyltrimethylammonium bromide (CTAB) as the silica source and surfactant respectively. The initial part of this study determined the effect of TBOS height and humidity on fiber formation. From this study, the range of TBOS heights for best microscopic and macroscopic ordering were established. Next, the CDSA method was used to successfully synthesize membranes, which were characterized to have good support plugging and an ordered pore structure. Factors that influence membrane synthesis and plug microstructure were determined. SEM studies revealed the presence of gaps between the plugs and support pores, which occur due to shrinking of the plug on drying. Development of a novel liquid deposition method to seal these defects constituted the last part of this work. Post sealing, excess silica was removed by etching with hydrofluoric acid. Membrane quality was evaluated at each step using SEM and gas permeation measurements. After surfactant removal by liquid extraction, the membranes exhibited an O2 permeance of 1.65x10-6mol/m2.Pa.s and He/O2 selectivity of 3.30. The successful synthesis of this membrane is an exciting new development in the area of ordered mesoporous membrane technology.
Contributors
Seshadri, Shriya (Author) / Lin, Jerry Y. S. (Thesis advisor) / Dai, Lenore (Committee member) / Rege, Kaushal (Committee member) / Smith, David J. (Committee member) / Vogt, Bryan (Committee member) / Arizona State University (Publisher)
Created
2011
Description
This research is about urban homeless people's vulnerability to extreme temperatures and the related socio-spatial dynamics. Specifically, this research investigates heat related coping strategies homeless people use and how the urban environment setting impacts those coping strategies. Semi-structured interviews were conducted with homeless people in Phoenix, Arizona during the summer of 2010. The findings demonstrate that homeless people have a variety of coping strategies and the urban environment setting unjustly impacts those strategies. The results suggest a need for further studies that focus spatial environmental effects on homeless people and other vulnerable populations.
Contributors
Sanchez, Cory (Author) / Johnson, John M. (Thesis advisor) / Harlan, Sharon L (Committee member) / Lauderdale, Pat (Committee member) / Arizona State University (Publisher)
Created
2011
Description
This dissertation explores the rhetorical significance of persecution claims produced by demonstrably powerful publics in contemporary American culture. This ideological criticism is driven by several related research questions. First, how do members of apparently powerful groups (men, whites, and Christians) come to see themselves as somehow unjustly marginalized, persecuted, or powerless? Second, how are these discourses related to the public sphere and counterpublicity? I argue that, despite startling similarities, these texts studied here are best understood not as counterpublicity but as a strategy of containment available to hegemonic publics. Because these rhetorics of persecution often seek to forestall movements toward pluralism and restorative justice, the analysis forwarded in this dissertation offers important contributions to ongoing theoretical discussions in the fields of public sphere theory and critical cultural theory and practical advice for progressive political activism and critical pedagogy.
Contributors
Duerringer, Christopher (Author) / Brouwer, Daniel (Thesis advisor) / Carlson, Cheree (Committee member) / McDonald, Kelly (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Encouraging stair use may increase physical activity among college students. The overall goals of this study were to quantitatively and qualitatively evaluate a stair use initiative, which included a mural painting contest in a residential hall. The number of individuals exiting the stairs were counted and interview data were obtained regarding the visibility of the signs and murals and whether the signs or murals influenced stair use. Focus groups and interviews were conducted with the community assistants (CAs) and staff members involved with the project to obtain qualitative data on their perceptions and opinions of the mural painting event. It was hypothesized that the average number of individuals per half hour who used the stairs would significantly increase from baseline to post-test. To examine changes over time in individuals exiting the stairs, a quasi-experimental design was used with one baseline measurement and multiple posttests (n=5). Stair use was determined by counting individuals exiting the stairwells. Time differences in exiting stair use were examined with repeated measures analysis of variance (ANOVA). Descriptive statistics and t-tests were used to analyze interview data. Qualitative data were analyzed using a thematic analysis approach. There was a significant time effect on stair use (F=7.512, p =0.000) and a significant interaction between staircase and time (F=7.518, p=0.000). There was no significant interaction of gender over time (F=.037, p=0.997). A repeated measures ANOVA was conducted on each staircase individually and showed that significant time differences were only found in the Southwest staircase. Based on exit interviews (n=28), most students saw the directional signs (61%) and murals (89.3%). However, neither the signs (71.4%) nor the murals (82.1%) were perceived as influential on stair use. Data from the focus groups and interviews revealed that the mural painting contest did not occur as intended, because the contest piece did not take place. In conclusion, solely having residents of a residential hall paint murals in stairwells was insufficient for increasing stair use. A mural painting contest may be a viable approach if properly planned and implemented.
Contributors
Smith, Shannon (Author) / Der Ananian, Cheryl A. (Thesis advisor) / Ainsworth, Barbara E. (Committee member) / Borror, Connie M. (Committee member) / Ilchak, Debra L. (Committee member) / Swan, Pamela D. (Committee member) / Wharton, Christopher M. (Committee member) / Arizona State University (Publisher)
Created
2011
Description
After being awarded the Nobel Prize for Literature in 2009, Herta Müller attained great prominence around the world. Commentators, especially in English-speaking countries, seemed shocked by the decision. One of the primary concerns was that Müller was relatively unknown. This thesis seeks to address this and other concerns by looking at reviews of her works in German- and English-language publications both before and after the Nobel Prize was awarded. This thesis analyses chronologically the reception of her books beginning with Niederungen in 1982 and ending with the reception of her novel Atemschaukel in 2009. It compares the reception of the original German text to that of the English translation; therefore only works which have been translated and published in English are discussed. The study also shows that while Müller's work did not top the bestseller charts, at least before the Nobel Prize, she was hardly the completely unknown author that some in the English-language media believed. This thesis seeks to present trends in the reception as well as provide a basis for further study of the reception of Herta Müller.
Contributors
Stringham, Enikő (Author) / Horwath, Peter (Thesis advisor) / Orlich, Ileana (Committee member) / Alexander, John (Committee member) / Arizona State University (Publisher)
Created
2011
Description
In this dissertation Mexican American (MA) youths environmental risk contexts, HPA axis functioning and mental health symptomatology were investigated in two separate studies. In the first study, environmental risk contexts were examined utilizing a person-centered approach and focusing on MA adolescents' family, peer, and cultural risk factors in fifth grade (N = 750). Environmental contexts were then linked to mental health symptomatology in seventh grade. Results revealed three distinct environmental contexts: Low risk, Moderate risk-language, and High risk-peer. Youth in the High-risk peer context reported the highest levels of symptomatology; greater major depressive disorder (MDD), anxiety, conduct disorder (CD)/oppositional defiant disorder (ODD), and attention deficit hyperactive disorder (ADHD) symptoms than youth experiencing Low risk or Moderate risk-language context. Females, in particular, experiencing the High risk peer context appeared at greatest risk for MDD symptoms. Finally, adolescents in the Moderate risk-language context displayed similar levels of symptoms to the individuals in the Low risk context, with the exception of higher anxiety. This study suggested that MA youth live in unique environmental contexts and these contexts are differentially related to mental health symptomatology. In the second study, 98 MA youth participated in a three-day diurnal cortisol protocol in hopes of linking perceptions of discrimination and HPA diurnal cortisol rhythms. Results revealed that discrimination was related to greater overall cortisol output and marginally related to the cortisol awakening response and evening levels of cortisol. Results suggest that important physiological processes underlie the experiences of discrimination.
Contributors
Zeiders, Katharine H (Author) / Roosa, Mark W. (Thesis advisor) / Doane, Leah D. (Committee member) / Dumka, Larry (Committee member) / Enders, Craig E. (Committee member) / Updegraff, Kimberly A. (Committee member) / Arizona State University (Publisher)
Created
2011
Description
The release of organophosphorus compounds (OPs) and subsequent exposure to these compounds is of concern to humans and the environment. The goal of this work was to control the concentrations of gaseous OPs through interaction with sorbent oxides. Experimental and computational methods were employed to assess the interactions of dimethyl phosphite (DMHP), dimethyl methylphosphonate (DMMP), dimethyl ethylphosphonate (DMEP), diethyl ethylphosphonate (DEEP), and triethyl phosphate (TEP) with amorphous silica (a-silica), ã-alumina, and monoclinic zirconia (m-zirconia) for applications in air pollution control. Interactions of the selected OPs with a-silica were chosen as a baseline to determine the applicability of the computational predictions. Based on the a-silica results, computational methods were deemed valid for predicting the trends among materials with comparable interactions (e.g. -OH functionality of a-silica interacting with the phosphonyl O atoms of the OPs). Computational evaluations of the interactions with the OPs were extended to the oxide material, m-zirconia, and compared with the results for ã-alumina. It was hypothesized that m-zirconia had the potential to provide for the effective sorption of OPs in a manner superior to that of the a-silica and the ã-alumina surfaces due to the surface charges of the zirconium Lewis acid sites when coordinated in the oxidized form. Based on the computational study, the predicted heats of adsorption for the selected OPs onto m-zirconia were more favorable than those that were predicted for ã-alumina and a-silica. Experimental studies were carried out to confirm these computational results. M-zirconia nanoparticles were synthesized to determine if the materials could be utilized for the adsorption of the selected OPs. M-zirconia was shown to adsorb the OPs, and the heats of adsorption were stronger than those determined for commercial samples of a-silica. However, water interfered with the adsorption of the OPs onto m-zirconia, thus leading to heats of adsorption that were much weaker than those predicted computationally. Nevertheless, this work provides a first investigation of m-zirconia as a viable sorbent material for the ambient control of the selected gaseous OPs. Additionally, this work represents the first comparative study between computational predictions and experimental determination of thermodynamic properties for the interactions of the selected OPs and oxide surfaces.
Contributors
Siu, Eulalia Yuen-Yi (Author) / Andino, Jean M (Thesis advisor) / Forzani, Erica S (Committee member) / Hristovski, Kiril (Committee member) / Nielsen, David R (Committee member) / Pfeffer, Robert (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Remote sensing has demonstrated to be an instrumental tool in monitoring land changes as a result of anthropogenic change or natural disasters. Most disaster studies have focused on large-scale events with few analyzing small-scale disasters such as tornadoes. These studies have only provided a damage assessment perspective with the continued need to assess reconstruction. This study attempts to fill that void by examining recovery from the 1999 Moore, Oklahoma Tornado utilizing Landsat TM and ETM+ imagery. Recovery was assessed for 2000, 2001 and 2002 using spectral enhancements (vegetative and urban indices and a combination of the two), a recovery index and different statistical thresholds. Classification accuracy assessments were performed to determine the precision of recovery and select the best results. This analysis proved that medium resolution imagery could be used in conjunction with geospatial techniques to capture recovery. The new indices, Shortwave Infrared Index (SWIRI) and Coupled Vegetation and Urban Index (CVUI), developed for disaster management, were the most effective at discerning reconstruction using the 1.5 standard deviation threshold. Recovery rates for F-scale damages revealed that the most incredibly damaged areas associated with an F5 rating were the slowest to recover, while the lesser damaged areas associated with F1-F3 ratings were the quickest to rebuild. These findings were consistent for 2000, 2001 and 2002 also exposing that complete recovery was never attained in any of the F-scale damage zones by 2002. This study illustrates the significance the biophysical impact has on recovery as well as the effectiveness of using medium resolution imagery such as Landsat in future research.
Contributors
Wagner, Melissa A (Author) / Cerveny, Randall S. (Thesis advisor) / Myint, Soe W. (Thesis advisor) / Wentz, Elizabeth (Committee member) / Brazel, Anthony J. (Committee member) / Arizona State University (Publisher)
Created
2011
Description
In times of fast paced technology, the ability to differentiate quality differences between a reproduction and an original work of art has new urgency. The use of digital reproductions in the classroom is a useful and convenient teaching tool, but can convey visual distortions specifically in regards to texture, size, and color. Art educators often struggle to achieve a balance between incorporating the use of digital technology and fostering an appreciation for experiences with original artworks. The purpose of this study was to examine the ways in which Dewey's theory of experiential learning explains how thoroughly high school students differentiate between a reproduction and original artwork. This study also explored the influences of painting style (realistic or semi-abstract) and sequence on a student's ability to identify the differences and select a preference between the reproduction and original artwork. To obtain insight into how a student is able to differentiate between a reproduction and an original artwork, this study engaged 27 high school student participants in viewing a digital reproduction and the respective original artwork of one realistic and one semi-abstract painting at the ASU Art Museum. Analysis of qualitative and quantitative data suggests that sequence influences a student's ability to differentiate between a reproduction and original artwork. Students who saw reproductions before viewing the originals, demonstrated a more comprehensive understanding of the differences between the two presentation formats. Implications of this study include the recommendation that art educators address definitional issues surrounding the terms original and reproduction in their teaching, and consider collaborative ways to prepare students for meaningful experiences with original artworks.
Contributors
Uscher, Dawn (Author) / Erickson, Mary (Thesis advisor) / Stokrocki, Mary (Committee member) / Young, Bernard (Committee member) / Arizona State University (Publisher)
Created
2011
Description
The purpose of this project was to commission, perform, and discuss a new work for an instrument pairing not often utilized, oboe and percussion. The composer, Alyssa Morris, was selected in June 2009. Her work, titled Forecast, was completed in October of 2009 and premiered in February of 2010, as part of a program showcasing music for oboe and percussion. Included in this document is a detailed biography of the composer, a description of the four movements of Forecast, performance notes for each movement, a diagram for stage set-up, the full score, the program from the premiere performance with biographies of all the performers involved, and both a live recording and MIDI sound file. The performance notes discuss issues that arose during preparation for the premiere and should help avoid potential pitfalls. TrevCo Music, publisher of the work, graciously allowed inclusion of the full score. This score is solely for use in this document; please visit the publisher's website for purchasing information. The commission and documentation of this composition are intended to add to the repertoire for oboe in an unusual instrument pairing and to encourage further exploration of such combinations.
Contributors
Creamer, Caryn (Author) / Schuring, Martin (Thesis advisor) / Hill, Gary (Committee member) / Holbrook, Amy (Committee member) / Micklich, Albie (Committee member) / Spring, Robert (Committee member) / Arizona State University (Publisher)
Created
2011