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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

James (Santa Fe) Galloway’s Alabado And The Musical Traditions Of The Penitentes

Weidman-Winter, Rebecca 12 1900 (has links)
This dissertation explores the musical traditions of the Penitentes of New Mexico and how these traditions influenced James (Santa Fe) Galloway’s Alabado for soprano, alto flute, and piano. Due to geographical isolation and religious seclusion the music of the Penitential Brotherhood is not well known outside of these New Mexican communities. The focus of this study, as pertaining to the music of the Penitentes, is the alabado “Por el rastro de la cruz,” and the pito, a handmade wooden flute. Included in this paper are transcriptions of pito melodies performed by Vicente Padilla, Cleofes Vigil, Emilio Ortiz, and Reginald Fisher, which have been transcribed by John Donald Robb, William R. Fisher, Reginald Fisher, and Rebecca Weidman-Winter. Few resources are available on Galloway or Alabado, an unpublished work, yet the popularity of this piece is apparent from the regular performances at the National Flute Association Conventions and by flutists throughout the United States. This paper represents a significant contribution to the study of Alabado, the composer, and how this composition reflects the music, history, and people of New Mexico.
72

Oxidation of Iron

Goursat, Albert Gilbert 08 1900 (has links)
<p> The main objective of this study was to gain an understanding of the oxidation properties of iron at low oxygen pressures and at high temperature. </p> <p> A thermogravimetric technique was employed to investigate the oxidation of iron in oxygen over the pressure range 2.5×10⁻³ - 3.0×10⁻¹ torr at temperatures ranging between 750ºC and 1000ºC. The oxidation curves exhibited distinct intervals of linear kinetics followed by transition to intervals of parabolic kinetics during exposures extending to 125 min. Linear kinetics governing the growth of uniformly thick wustite scales; the linear rate constants showed a proportional dependence on oxygen pressure due to reaction control by a phase boundary reaction involving non-dissociation adsorption of oxygen. Parabolic kinetics governed growth of wustite-magnetite scales containing magnetite as outermost layers. The value of the parabolic rate constants were independent of oxygen pressure since scale growth was directly dependent on the iron vacancy gradient in wustite established by the oxygen activities at the Fe/FeO and FeO/Fe₃O₄ interfaces. </p> <p> Scanning electron microscopy techniques were used to gain information on the growth of magnetite and hematite layers in the multilayer scale consisting largely of wustite formed at high temperature in the pressure range 2.5×10⁻³ to 760 torr. </p> / Thesis / Master of Science (MSc)
73

Analysis of Barge Impact with Bridge Pier

Miller, Anna Marie 17 August 2013 (has links)
The Mississippi River Bridge in Vicksburg, MS is a 7 span cantilever bridge that is 3,389 feet long by 68.5 feet wide and is part of the Interstate-20 corridor. On March 23, 2011 at 1:30pm, a barge moving downstream struck a pier of the bridge. Infrasound stations located at the U.S. Army Engineer Research and Development Center (ERDC) detected the impact. Coincidentally, ERDC had instrumented the bridge with strain gages and accelerometers as part of a structural health monitoring project. Finite Element (FE) models were developed to investigate the structural behavior of the bridge due to the impact. The measurements and the FE models were used to determine the source mechanism of the infrasound from the bridge. Measurements from the sensors that were installed on the bridge will be presented along with FE models and infrasound data.
74

Causes of whitening of ivy geraniums (Pelargonium peltatum)

Dhir, Ritu 03 May 2008 (has links)
The development of whitening of the youngest leaves of actively growing ivy geranium (Pelargonium peltatum L.) has been observed as the season changes from late spring to summer. This study was conducted to determine the specific environmental causes of whitening, if micronutrients deficiencies cause similar whitening, whether low night temperatures can reverse whitening, and whether salicylic acid affects growth and whitening in ivy geraniums. Two cultivars, ‘Beach’ and ‘Butterfly’, with different susceptibility to whitening were chosen for this study. Elevated air temperature, but not elevated root-zone temperature, was found to be the environmental cause of whitening in ivy geranium. Elevated air temperatures severely reduced plant growth, leaf area, fresh weight, and dry weight in both cultivars. Elevated air temperature reduced photosynthetic pigments and their ratios in ivy geranium. Carotenoids and pheophytins decreased in ‘Butterfly’ at elevated air temperature. Foliar total Fe levels indicated no inhibition of Fe-uptake at elevated temperatures. Applications of Fe-chelate at elevated temperatures helped chlorophyll synthesis in ivy geraniums. Deficiency treatments of all micronutrients, Fe, Mn, Zn, S or Mg did not result in whitening in either cultivar of ivy geraniums. Salicylic acid did not affect whitening of ivy geraniums. It did not affect growth, leaf area, fresh or dry (stem, leaf or total) weight, fresh: dry weight ratio, leaf area ratio, specific leaf area or foliar nutrient (Fe, Mn, Zn, Mg and S) content in either cultivar. Cultivars varied in their response to low night temperature. ‘Beach’ reduced its plant growth and fresh to dry weight ratio whereas ‘Butterfly’ did not. Fe-chelate application did not reduce growth, leaf area, fresh weight, dry weight or fresh:dry weight ratio of either cultivar. Although Fe-application did not reduce whitening in ivy geraniums, it helped to preserve chlorophyll, particularly chlorophyll b as indicated by Chl a:b ratio in ‘Beach’. Whitening in ivy geranium is a heat stress response initially exhibited by young, developing leaves and is caused by elevated air temperatures. Whitening is the result of impaired photosynthetic pigments synthesis and/or degradation.
75

AN AUTOMATIC CALIBRATION STRATEGY FOR 3D FE BRIDGE MODELS

LIU, LEI 05 October 2004 (has links)
No description available.
76

Generalized hybrid methods for modeling complex electromagnetic structures

Usner, Brian C. 06 January 2006 (has links)
No description available.
77

Effect of Small Cerium Additions on Microstructure and Mechanical Properties of Al-Mg-Fe Alloy

Yan, Xiaofei 09 1900 (has links)
<p>The application aluminum sheet alloy for light vehicle development was limited by the high cost of alloy fabrication. The impurity iron, which is easily picked up during fabrication, deteriorates its formability. The sheet alloy produced by continuous casting techniques was showing lower in-service performance than the one produced with traditional high-cost direct-chill casting technique. Therefore, enhancing the general formability of the aluminum alloy became .the aim of many researchers and engineers in past decades.</p><p>This project was launched to detect a possible modification effect of rare-earth (RE) element on a Al-Mg-Fe alloy, which is a simplified AA5754 alloy. Cerium was chosen as the RE element to test with. The influence of this rare-earth element on the alloy grain microstructure, phase morphology, and corresponding mechanical behavior was investigated.</p><p>It was found that cerium had a modification effect on the phase morphology to some extent. Its addition provided a great grain refinement in as-cast alloys. However, after thermo-mechanical processing, this effect would be eliminated by the small broken particles and recrystallized fine grains. It was found that the mechanical performance of the cerium-containing AA5754 was neither enhanced nor deteriorated. The AA5754 alloy remained non-heat-treatable after the addition of cerium.</p> / Thesis / Master of Applied Science (MASc)
78

Interaction Between Oxidation and Stress at High Temperatures on Scale Growth of Fe-Cr-Al Based Alloy

Khiev, Somaradi 02 1900 (has links)
The need for environmentally friendly and energy efficient high temperature components that can operate under mechanical and/or thermal stress has prompted interest in the development of Fe-Cr-Al based alloys. These alloys have been widely investigated, because of their ability to form a protective layer of a - Al203, which is able to withstand further oxidation degradation. However, despite their superior oxidation qualities, alpha-alumina scales are highly susceptible to mechanical damage when subjected to aggressive environments. The origins of such failure can be attributed to the generation and relaxation of stresses during the scaling process. As such, this study has experimentally investigated the interaction between oxidation and stress on Fe-Cr-Al based alloy, Kanthal Al. Oxidation experiments of Kanthal Al were conducted in two parts. First, the alloy's scaling process at rest with respect to intrinsic growth stress and oxide morphology was examined. Second, external stress was applied during oxidation to obtain a comprehensive understanding of its effect on scale growth with comparison to experiments conducted without stress. The formation of compact α - Al203 scales was accompanied by compressive growth stresses on the order of 1 GPa. Prolonged oxidation decreased growth stresses resulting in increased scale porosity. Maximum scale porosity occurred under oxidation at 1300°C. Consequently, the protectiveness of the scale was heavily degraded, as indicated by scale morphology, implying that in-service operation at this temperature or above would be detrimental. Applied tensile stress showed a significant decrease in the development of intrinsic growth stress, suggesting a strong interdependency between scale growth stress and creep deformation at high temperature. There was no measurable change in the scale growth rate, as compared to experiments conducted at rest. Possible explanations include insufficient tensile load and/or drastic increase in spallation/rehealing, both of which simultaneously influences the lifetime of a material under aggressive operational conditions. / Thesis / Master of Applied Science (MASc)
79

FE analysis of the effect of real brake contact areas on brake surface temperatures

Zhao, Y., Qi, Hong Sheng, Day, Andrew J. 26 January 2009 (has links)
No
80

Arsenic mobilization through bioreduction of iron oxide nanoparticles

Roller, Jonathan William 18 August 2004 (has links)
Arsenic sorbs strongly to the surfaces of Fe(III) (hydr)oxides. Under aerobic conditions, oxygen acts as the terminal electron acceptor in microbial respiration and Fe(III) (hydr)oxides are highly insoluble, thus arsenic remains associated with Fe(III) (hydr)oxide phases. However, under anaerobic conditions Fe(III)-reducing microorganisms can couple the reduction of solid phase Fe(III) (hydr)oxides with the oxidation of organic carbon. When ferric iron is reduced to ferrous iron, arsenic is mobilized into groundwater. Although this process has been documented in a variety of pristine and contaminated environments, minimal information exists on the mechanisms causing this arsenic mobilization. Arsenic mobilization was studied by conducting controlled microcosm experiments containing an arsenic-bearing ferrihydrite and an Fe(III)-reducing microorganism, Geobacter metallireducens. Results show that arsenic mobility is strongly controlled by microbially-mediated disaggregation of arsenic-bearing iron nanoparticles. The most likely controlling mechanism of this disaggregation of iron oxide nanoparticles is a change in mineral phase from ferrihydrite to magnetite, a mixed Fe(III) and Fe(II) mineral, due to the microbially-mediated reduction of Fe(III). Although arsenic remained associated with the iron oxide nanoparticles and was not released as a hydrated oxyanion, the arsenic-bearing nanoparticles could be readily mobilized in aquifers. These results have significant implications for understanding arsenic behavior in aquifers with Fe(III) reducing conditions, and may aid in improving remediation of arsenic-contaminated waters. / Master of Science

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