Matching Items (43,917)
Description
A new analytical method is proposed for measuring the deuterium to hydrogen ratio (D/H) of non-stoichiometric water in hydrous minerals via pyrolysis facilitated gas-chromatography - isotope ratio mass spectrometry (GC-IRMS). Previously published analytical methods have reported a poorly understood nonlinear dependence of D/H on sample size, for which any accurate correction is difficult. This sample size effect been variously attributed to kinetic isotope fractionation within the mass spectrometer and peripheral instruments, ion source linearity issues, and an unstable H_3^+-factor or incorrect H_3^+-factor calculations. The cause of the sample size effect is here identified by examinations of individual chromatograms as well as bulk data from chromatographic peaks. It is here determined that it is primarily an artifact of the calculations employed by the manufacturer's computer program, used to both monitor the functions of the mass spectrometer and to collect data. Ancillary causes of the sample size effect include a combination of persistent background interferences and chromatographic separation of the isotopologues of molecular hydrogen. Previously published methods are evaluated in light of these findings. A new method of H_3^+-factor and D/H calculation is proposed which makes portions of the Isodat software as well as other published calculation methods unnecessary. Using this new method, D/H is measured in non-stoichiometric water in chert from the Cretaceous Edwards Group, Texas, as well as the Precambrian Kromberg Formation, South Africa, to assess hydrological conditions as well as to estimate the maximum average surface temperature during precipitation of the chert. Data from Cretaceous chert are consistent with previously published data and interpretations, based upon conventional analyses of large samples. Data from Precambrian chert are consistent with maximum average surface temperatures approaching 65°C during the Archean, instead of the much lower temperatures derived from erroneous methods of sample preparation and analysis. D/H is likewise measured in non-stoichiometric water in silicified basalt from the Precambrian Hooggenoeg Complex, South Africa. Data are shown to be consistent with D/H of the Archean ocean similar to present day values.
Contributors
Sheehan, Michael Robert (Author) / Knauth, Leroy P (Thesis advisor) / Anbar, Ariel (Committee member) / Farmer, Jack (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Increasing demand for high strength powder metallurgy (PM) steels has resulted in the development of dual phase PM steels. In this work, the effects of thermal aging on the microstructure and mechanical behavior of dual phase precipitation hardened powder metallurgy (PM) stainless steels of varying ferrite-martensite content were examined. Quantitative analyses of the inherent porosity and phase fractions were conducted on the steels and no significant differences were noted with respect to aging temperature. Tensile strength, yield strength, and elongation to fracture all increased with increasing aging temperature reaching maxima at 538oC in most cases. Increased strength and decreased ductility were observed in steels of higher martensite content. Nanoindentation of the individual microconstituents was employed to obtain a fundamental understanding of the strengthening contributions. Both the ferrite and martensite hardness values increased with aging temperature and exhibited similar maxima to the bulk tensile properties. Due to the complex non-uniform stresses and strains associated with conventional nanoindentation, micropillar compression has become an attractive method to probe local mechanical behavior while limiting strain gradients and contributions from surrounding features. In this study, micropillars of ferrite and martensite were fabricated by focused ion beam (FIB) milling of dual phase precipitation hardened powder metallurgy (PM) stainless steels. Compression testing was conducted using a nanoindenter equipped with a flat punch indenter. The stress-strain curves of the individual microconstituents were calculated from the load-displacement curves less the extraneous displacements of the system. Using a rule of mixtures approach in conjunction with porosity corrections, the mechanical properties of ferrite and martensite were combined for comparison to tensile tests of the bulk material, and reasonable agreement was found for the ultimate tensile strength. Micropillar compression experiments of both as sintered and thermally aged material allowed for investigation of the effect of thermal aging.
Contributors
Stewart, Jennifer (Author) / Chawla, Nikhilesh (Thesis advisor) / Jiang, Hanqing (Committee member) / Krause, Stephen (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Yannis Constantinidis was the last of the handful of composers referred to collectively as the Greek National School. The members of this group strove to create a distinctive national style for Greece, founded upon a synthesis of Western compositional idioms with melodic, rhyhmic, and modal features of their local folk traditions. Constantinidis particularly looked to the folk melodies of his native Asia Minor and the nearby Dodecanese Islands. His musical output includes operettas, musical comedies, orchestral works, chamber and vocal music, and much piano music, all of which draws upon folk repertories for thematic material. The present essay examines how he incorporates this thematic material in his piano compositions, written between 1943 and 1971, with a special focus on the 22 Songs and Dances from the Dodecanese. In general, Constantinidis's pianistic style is expressed through miniature pieces in which the folk tunes are presented mostly intact, but embedded in accompaniment based in early twentieth-century modal harmony. Following the dictates of the founding members of the Greek National School, Manolis Kalomiris and Georgios Lambelet, the modal basis of his harmonic vocabulary is firmly rooted in the characteristics of the most common modes of Greek folk music. A close study of his 22 Songs and Dances from the Dodecanese not only offers a valuable insight into his harmonic imagination, but also demonstrates how he subtly adapts his source melodies. This work also reveals his care in creating a musical expression of the words of the original folk songs, even in purely instrumental compositon.
Contributors
Savvidou, Dina (Author) / Hamilton, Robert (Thesis advisor) / Little, Bliss (Committee member) / Meir, Baruch (Committee member) / Thompson, Janice M (Committee member) / Arizona State University (Publisher)
Created
2011
Description
This qualitative study explores the learning experiences of two first-grade teachers in a progressive public elementary school in the southwestern U.S. Participants inquired into their literacy instruction practices within their reading-workshops. Weekly inquiry group conversations between teachers and researcher informed a perspective of learning as participation. During the semester-long study, two key questions guided design and implementation: 1) What is the nature of teachers' learning experiences related to their literacy instruction practices, contextualized within an inquiry group? 2) How do those learning experiences reflect and/or refract the community, interpersonal, and individual planes of analysis? An ethnographic perspective informed data collection and analysis; data were collected through weekly inquiry-group conversations, bi-weekly classroom observations, and in-depth interviews. A learning framework of community, interpersonal, and individual planes of analysis served as an analytic tool used in conjunction with a modified analytic induction. Teachers' case studies offer unique accounts of their learning, contextualized within their specific classrooms. Findings are discussed through narrative-based vignettes, which illustrate teachers' learning trajectories. On the community plane, apprenticeship relationships were evident in teachers' interactions with students' parents and with one another. Interpersonal interactions between teachers demonstrated patterns of participation wherein each tried to teach the other as they negotiated their professional identities. Analysis of the individual plane revealed that teachers' past experiences and personal identities contributed to ways of participation for both teachers that were highly personal and unique to each. Affective considerations in learning were a significant finding within this study, adding dimensionality to this particular sociocultural theory of learning. The ways teachers felt about themselves, their students, their community, and their work constituted a significant influence on what they said and did, as demonstrated on all three planes of analysis. Implications for practice include the significance of professional development efforts that begin at the site of teachers' questions, and attention to teachers' individual learning trajectories as a means to supporting educators to teach in more confident and connected ways.
Contributors
Steeg, Susanna Mae (Author) / Mccarty, Teresa L. (Thesis advisor) / Fischman, Gustavo E. (Committee member) / Marsh, Josephine P. (Committee member) / Smith, Karen (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Libertarians affirm the right to liberty, i.e., the right to do what one wants free from interference. Libertarians also affirm the right to private property. One objection to libertarianism is that private property relations restrict liberty. This objection appears to have the consequence that libertarianism is an incoherent position. I examine Jan Narveson's version of the libertarian view and his defense of its coherence. Narveson understands the right to liberty as a prohibition on the initiation of force. I argue that if that is what the right to liberty is, then the enforcement of property rights violates it. I also examine Narveson's attempt to support private property with his distinction between interference with and mere prevention of activity and argue that this distinction does not do the work that he needs it to do. My conclusion is that libertarianism is, in a sense, impossible because conceptually unsound.
Contributors
Schimke, Christopher (Author) / de Marneffe, Peter (Thesis advisor) / McGregor, Joan (Committee member) / Blackson, Thomas (Committee member) / Arizona State University (Publisher)
Created
2011
Description
The green building movement has been an effective catalyst in reducing energy demands of buildings and a large number of `green' certified buildings have been in operation for several years. Whether these buildings are actually performing as intended, and if not, identifying specific causes for this discrepancy falls into the general realm of post-occupancy evaluation (POE). POE involves evaluating building performance in terms of energy-use, indoor environmental quality, acoustics and water-use; the first aspect i.e. energy-use is addressed in this thesis. Normally, a full year or more of energy-use and weather data is required to determine the actual post-occupancy energy-use of buildings. In many cases, either measured building performance data is not available or the time and cost implications may not make it feasible to invest in monitoring the building for a whole year. Knowledge about the minimum amount of measured data needed to accurately capture the behavior of the building over the entire year can be immensely beneficial. This research identifies simple modeling techniques to determine best time of the year to begin in-situ monitoring of building energy-use, and the least amount of data required for generating acceptable long-term predictions. Four analysis procedures are studied. The short-term monitoring for long-term prediction (SMLP) approach and dry-bulb temperature analysis (DBTA) approach allow determining the best time and duration of the year for in-situ monitoring to be performed based only on the ambient temperature data of the location. Multivariate change-point (MCP) modeling uses simulated/monitored data to determine best monitoring period of the year. This is also used to validate the SMLP and DBTA approaches. The hybrid inverse modeling method-1 predicts energy-use by combining a short dataset of monitored internal loads with a year of utility-bills, and hybrid inverse method-2 predicts long term building performance using utility-bills only. The results obtained show that often less than three to four months of monitored data is adequate for estimating the annual building energy use, provided that the monitoring is initiated at the right time, and the seasonal as well as daily variations are adequately captured by the short dataset. The predictive accuracy of the short data-sets is found to be strongly influenced by the closeness of the dataset's mean temperature to the annual average temperature. The analysis methods studied would be very useful for energy professionals involved in POE.
Contributors
Singh, Vipul (Author) / Reddy, T. Agami (Thesis advisor) / Bryan, Harvey (Committee member) / Addison, Marlin (Committee member) / Arizona State University (Publisher)
Created
2011
Description
With the rapid growth of mobile computing and sensor technology, it is now possible to access data from a variety of sources. A big challenge lies in linking sensor based data with social and cognitive variables in humans in real world context. This dissertation explores the relationship between creativity in teamwork, and team members' movement and face-to-face interaction strength in the wild. Using sociometric badges (wearable sensors), electronic Experience Sampling Methods (ESM), the KEYS team creativity assessment instrument, and qualitative methods, three research studies were conducted in academic and industry R&D; labs. Sociometric badges captured movement of team members and face-to-face interaction between team members. KEYS scale was implemented using ESM for self-rated creativity and expert-coded creativity assessment. Activities (movement and face-to-face interaction) and creativity of one five member and two seven member teams were tracked for twenty five days, eleven days, and fifteen days respectively. Day wise values of movement and face-to-face interaction for participants were mean split categorized as creative and non-creative using self- rated creativity measure and expert-coded creativity measure. Paired-samples t-tests [t(36) = 3.132, p < 0.005; t(23) = 6.49 , p < 0.001] confirmed that average daily movement energy during creative days (M = 1.31, SD = 0.04; M = 1.37, SD = 0.07) was significantly greater than the average daily movement of non-creative days (M = 1.29, SD = 0.03; M = 1.24, SD = 0.09). The eta squared statistic (0.21; 0.36) indicated a large effect size. A paired-samples t-test also confirmed that face-to-face interaction tie strength of team members during creative days (M = 2.69, SD = 4.01) is significantly greater [t(41) = 2.36, p < 0.01] than the average face-to-face interaction tie strength of team members for non-creative days (M = 0.9, SD = 2.1). The eta squared statistic (0.11) indicated a large effect size. The combined approach of principal component analysis (PCA) and linear discriminant analysis (LDA) conducted on movement and face-to-face interaction data predicted creativity with 87.5% and 91% accuracy respectively. This work advances creativity research and provides a foundation for sensor based real-time creativity support tools for teams.
Contributors
Tripathi, Priyamvada (Author) / Burleson, Winslow (Thesis advisor) / Liu, Huan (Committee member) / VanLehn, Kurt (Committee member) / Pentland, Alex (Committee member) / Arizona State University (Publisher)
Created
2011
Description
This study examined attitudes and perspectives of classroom guitar students toward the reading of staff notation in music. The purpose of this qualitative research was to reveal these perceptions in the student's own words, and compare them to those of orchestra and band students of comparable experience. Forty-seven students from four suburban middle and high schools on the east coast were selected through purposeful sampling techniques. Research instruments included a Musical Background Questionnaire and a thirty-five question Student Survey. Follow-up interviews were conducted with students to clarify or expound upon collected data. Guitar, orchestra, and band teachers were interviewed in order to provide their perspectives on the issues discussed. The Student Survey featured a five-point Likert-type scale, which measured how much students agreed or disagreed with various statements pertaining to their feelings about music, note-reading, or their class at school. Collected data were coded and used to calculate mean scores, standard deviations, and percentages of students in agreement or disagreement with each statement. Interviews were audio recorded and transcribed into a word processing document for analysis. The study found that while a variety of perspectives exist within a typical guitar class, some students do not find note-reading to be necessary for the types of music they desire to learn. Other findings included a perceived lack of relevance toward the classical elements of the guitar programs in the schools, a lack of educational consistency between classroom curricula and private lesson objectives, and the general description of the struggle some guitarists experience with staff notation. Implications of the collected data were discussed, along with recommendations for better engaging these students.
Contributors
Ward, Stephen Michael (Author) / Koonce, Frank (Thesis advisor) / Schmidt, Margaret (Thesis advisor) / Buck, Nancy (Committee member) / Rogers, Rodney (Committee member) / McLin, Katherine (Committee member) / Arizona State University (Publisher)
Created
2011
Description
Concern regarding the quality of traffic data exists among engineers and planners tasked with obtaining and using the data for various transportation applications. While data quality issues are often understood by analysts doing the hands on work, rarely are the quality characteristics of the data effectively communicated beyond the analyst. This research is an exercise in measuring and reporting data quality. The assessment was conducted to support the performance measurement program at the Maricopa Association of Governments in Phoenix, Arizona, and investigates the traffic data from 228 continuous monitoring freeway sensors in the metropolitan region. Results of the assessment provide an example of describing the quality of the traffic data with each of six data quality measures suggested in the literature, which are accuracy, completeness, validity, timeliness, coverage and accessibility. An important contribution is made in the use of data quality visualization tools. These visualization tools are used in evaluating the validity of the traffic data beyond pass/fail criteria commonly used. More significantly, they serve to educate an intuitive sense or understanding of the underlying characteristics of the data considered valid. Recommendations from the experience gained in this assessment include that data quality visualization tools be developed and used in the processing and quality control of traffic data, and that these visualization tools, along with other information on the quality control effort, be stored as metadata with the processed data.
Contributors
Samuelson, Jothan P (Author) / Pendyala, Ram M. (Thesis advisor) / Ahn, Soyoung (Committee member) / Arizona State University (Publisher)
Created
2011
Description
HIV/AIDS is the sixth leading cause of death worldwide and the leading cause of death among women of reproductive age living in low-income countries. Clinicians in industrialized nations monitor the efficacy of antiretroviral drugs and HIV disease progression with the HIV-1 viral load assay, which measures the copy number of HIV-1 RNA in blood. However, viral load assays are not widely available in sub-Saharan Africa and cost between 50-$139 USD per test on average where available. To address this problem, a mixed-methods approach was undertaken to design a novel and inexpensive viral load diagnostic for HIV-1 and to evaluate barriers to its adoption in a developing country. The assay was produced based on loop-mediated isothermal amplification (LAMP). Blood samples from twenty-one individuals were spiked with varying concentrations of HIV-1 RNA to evaluate the sensitivity and specificity of LAMP. Under isothermal conditions, LAMP was performed with an initial reverse-transcription step (RT-LAMP) and primers designed for HIV-1 subtype C. Each reaction generated up to a few billion copies of target DNA within an hour. Presence of target was detected through naked-eye observation of a fluorescent indicator and verified by DNA gel electrophoresis and real-time fluorescence. The assay successfully detected the presence of HIV in samples with a broad range of HIV RNA concentration, from over 120,000 copies/reaction to 120 copies/reaction. In order to better understand barriers to adoption of LAMP in developing countries, a feasibility study was undertaken in Tanzania, a low-income country facing significant problems in healthcare. Medical professionals in Northern Tanzania were surveyed for feedback regarding perspectives of current HIV assays, patient treatment strategies, availability of treatment, treatment priorities, HIV transmission, and barriers to adoption of the HIV-1 LAMP assay. The majority of medical providers surveyed indicated that the proposed LAMP assay is too expensive for their patient populations. Significant gender differences were observed in response to some survey questions. Female medical providers were more likely to cite stigma as a source problem of the HIV epidemic than male medical providers while males were more likely to cite lack of education as a source problem than female medical providers.
Contributors
Salamone, Damien Thomas (Author) / Jacobs, Bertram L (Thesis advisor) / Marsiglia, Flavio (Committee member) / Stout, Valerie (Committee member) / Johnson, Crista (Committee member) / Arizona State University (Publisher)
Created
2011