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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.
21

Experimental study of shear and compaction band formation in berea sandstone

Herrin, Elizabeth Anne 15 May 2009 (has links)
Many field, experimental, and theoretical studies have contributed greatly to our understanding of the occurrence and formation of deformation bands in porous granular materials, but questions remain regarding the mechanics of strain localization, and how the orientation, thickness and internal strain (shear relative to volume change) of deformation bands is influenced by loading history and evolving rock properties. Here we report on triaxial rock deformation experiments using a non-traditional sample geometry to investigate band formation across the brittle-ductile transition. Five-cm diameter cylinders of Berea sandstone were machined with a circular (8.77 cm radius) notch to form a dog-bone sample geometry. In triaxial compression, the sample geometry obviates end-effects without creating heterogeneous stress gradients that can influence localization. Samples were instrumented to measure local strains in the neck region and acoustic emissions (AE), and then shortened to failure at confining pressures of 50 to 250 MPa. Deformation bands formed at all conditions, and photo mosaics of the outer sample surface were used to determine the thickness and orientation of the bands. Band thickness increases from several to tens of mm thickness and the angle between the bands with the shortening axis changes from 35 to 80 degrees, as confining pressure increases from 50 to 250 MPa, respectively. Mechanical data, including local strain measurements through yield, were used to test theoretical models for the onset of localization and formation of deformation bands as an instability in the constitutive description of homogeneous deformation. Generally, theoretical predictions compare favorably with the observed onset of localization determined by marked changes in the AE rate, and are consistent with the formation of compacting shear bands at higher mean stress. Predictions of changes in band orientation with mean stress are largely consistent with observed trends, but deviate from the observed orientation by as much as twenty degrees.
22

Experimental study of shear and compaction band formation in berea sandstone

Herrin, Elizabeth Anne 15 May 2009 (has links)
Many field, experimental, and theoretical studies have contributed greatly to our understanding of the occurrence and formation of deformation bands in porous granular materials, but questions remain regarding the mechanics of strain localization, and how the orientation, thickness and internal strain (shear relative to volume change) of deformation bands is influenced by loading history and evolving rock properties. Here we report on triaxial rock deformation experiments using a non-traditional sample geometry to investigate band formation across the brittle-ductile transition. Five-cm diameter cylinders of Berea sandstone were machined with a circular (8.77 cm radius) notch to form a dog-bone sample geometry. In triaxial compression, the sample geometry obviates end-effects without creating heterogeneous stress gradients that can influence localization. Samples were instrumented to measure local strains in the neck region and acoustic emissions (AE), and then shortened to failure at confining pressures of 50 to 250 MPa. Deformation bands formed at all conditions, and photo mosaics of the outer sample surface were used to determine the thickness and orientation of the bands. Band thickness increases from several to tens of mm thickness and the angle between the bands with the shortening axis changes from 35 to 80 degrees, as confining pressure increases from 50 to 250 MPa, respectively. Mechanical data, including local strain measurements through yield, were used to test theoretical models for the onset of localization and formation of deformation bands as an instability in the constitutive description of homogeneous deformation. Generally, theoretical predictions compare favorably with the observed onset of localization determined by marked changes in the AE rate, and are consistent with the formation of compacting shear bands at higher mean stress. Predictions of changes in band orientation with mean stress are largely consistent with observed trends, but deviate from the observed orientation by as much as twenty degrees.
23

Factors related to students' decisions to continue in band

Stewart, Jennifer Laura 28 August 2008 (has links)
Not available / text
24

A survey and evaluation of music performed in public concert by Indiana high school bands

Fjeld, Marvin Wendell January 1959 (has links)
There is no abstract available for this dissertation.
25

A study of factors that may contribute to the variation in high school band festival ratings at the district and state levels in the State of Maryland

Litzinger, Herman Anthony January 1968 (has links)
There is no abstract available for this dissertation.
26

Effect of heat treatment on stability of adiabatic shear bands in 4340 steel

Boakye -Yiadom, Solomon 19 January 2011 (has links)
The fingerprint of deformation in materials at large strains and at high strain rates is the formation of adiabatic shear bands. Adiabatic shear bands lead to unexpected failure of materials during service. This study investigated the possibility of eliminating adiabatic shear bands from materials subjected to severe deformation at high strain rates by post impact heat treatment. Five groups of cylindrical AISI 4340 steel samples were impacted using the Direct Impact Hopkinson Pressure Bar (DIHPB) developed at the University of Manitoba. Selected impacted samples with distinct transformed shear bands were soaked at 350⁰C to 850⁰C for periods ranging from 30 minutes to 4 hours to investigate how temperature and time affects the properties and structure of the shear bands. Annealing the shear bands at 350⁰C resulted in an increase in hardness of the shear bands and the surrounding material outside the shear bands regardless of the heat treatment before impact, amount of deformation, and the time of annealing. Significant decrease in hardness of the shear bands occurred after post impact annealing at 650⁰C for 30 minutes and 2 hours. Hardness of the shear bands reduced to the same level as that of the impacted material outside the shear bands. However, the initial path of the shear bands in the impacted steel samples could be traced through a “signature” left after the annealing. Post-impact annealing of the steel samples at 750⁰C and 850⁰C resulted in a homogenous microstructure with no trace of the shear bands. The “signatures” which were used to trace the path of the shear bands in impacted samples annealed at 650⁰C disappeared and the hardness across the samples became uniform. The observations from this study show that adiabatic shear bands in typical steel can be eliminated by annealing heat treatment. The temperature of annealing is the most critical parameter and the annealing should be performed above 650⁰C.
27

Development of a structured method of mental practice and its effect on the performance of high school band students

Galyen, Stephen Daniel. January 2006 (has links)
Thesis (Ph. D.)--University of Florida, 2006. / Title from title page of source document. Document formatted into pages; contains 297 pages. Includes vita. Includes bibliographical references.
28

A survey of perceptions of at-risk students by Florida secondary school band directors

Chipman, Shelby Rawn. Shellahamer, Bentley. January 2004 (has links)
Dissertation (Ph. D.) -- Florida State University, 2004. / Advisor: Bentley Shellahamer, Florida State University, School of Music. Title and description from dissertation home page (viewed 9-24-04). Document formatted into pages; contains 188 pages. Includes biographical sketch. Includes bibliographical references.
29

Florida Bandmasters Association's "Significant literature" selected for music performance assessments

Norona, David Henry. VanWeelden, Kimberly. January 2008 (has links)
Thesis (M.M.E.) Florida State University, 2008. / Advisor: Kimberly VanWeelden, Florida State University College of Music. Title and description form dissertation home page (viewed 4-7-2009). Document formatted into pages; contains 103 pages.
30

An examination of Nebraska high school band directors' implementation of and attitudes toward the National Standards in Music

Zitek, J. Samuel. January 2008 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Mar. 31, 2009). PDF text: x, 154 p. ; 4 Mb. UMI publication number: AAT 3331177. Includes bibliographical references. Also available in microfilm and microfiche formats.

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