{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/20186"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/20186","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Radiative transfer of ultrasound","abstract":"Radiative transfer theory is used to model the multiple scattering of diffuse ultrasonic waves in two types of random media. The first type is an isotropic, homogeneous medium containing randomly oriented, randomly located scatterers. The scatterers are assumed to be uncorrelated. This assumption allows an equation of transfer to be written which governs the multiply scattered intensities. This ultrasonic radiative transfer equation (URTE) contains single scattering and propagation parameters that are calculated using the elastic wave equation. Polarization effects are included through the introduction of an elastodynamic Stokes vector which contains a longitudinal Stokes parameter and four shear Stokes parameters similar to the four Stokes parameters used in optical radiative transfer theory. The theory is applied to a statistically homogeneous isotropic half space containing randomly distributed spherical voids illuminated by a harmonic plane wave.","abstract_html":"Radiative transfer theory is used to model the multiple scattering of diffuse ultrasonic waves in two types of random media. The first type is an isotropic, homogeneous medium containing randomly oriented, randomly located scatterers. The scatterers are assumed to be uncorrelated. This assumption allows an equation of transfer to be written which governs the multiply scattered intensities. This ultrasonic radiative transfer equation (URTE) contains single scattering and propagation parameters that are calculated using the elastic wave equation. Polarization effects are included through the introduction of an elastodynamic Stokes vector which contains a longitudinal Stokes parameter and four shear Stokes parameters similar to the four Stokes parameters used in optical radiative transfer theory. The theory is applied to a statistically homogeneous isotropic half space containing randomly distributed spherical voids illuminated by a harmonic plane wave.","abstract_has_math":false,"creators":["Turner, Joseph Alan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Science","degree_department":null,"school":null,"contributors":["Weaver, Richard L."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T12:31:35Z","date_published":"2011-05-07T12:31:35Z","updated_at":"2026-07-22T22:25:15Z","subjects":["Applied Mechanics","Engineering, Materials Science","Physics, Acoustics"],"languages":["eng"],"rights":["Copyright 1994 Turner, Joseph Alan"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9512578","(UMI)AAI9512578"],"render_values":[{"text":"AAI9512578","href":null,"code":true},{"text":"(UMI)AAI9512578","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/20186","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Weaver, Richard L."]},{"key":"dc:creator","label":"Author","values":["Turner, Joseph Alan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T12:31:35Z","10000-01-01","1994"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Science"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Applied Mechanics","Engineering, Materials Science","Physics, Acoustics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1994 Turner, Joseph Alan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9512578","(UMI)AAI9512578","http://hdl.handle.net/2142/20186"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Radiative transfer theory is used to model the multiple scattering of diffuse ultrasonic waves in two types of random media. The first type is an isotropic, homogeneous medium containing randomly oriented, randomly located scatterers. The scatterers are assumed to be uncorrelated. This assumption allows an equation of transfer to be written which governs the multiply scattered intensities. This ultrasonic radiative transfer equation (URTE) contains single scattering and propagation parameters that are calculated using the elastic wave equation. Polarization effects are included through the introduction of an elastodynamic Stokes vector which contains a longitudinal Stokes parameter and four shear Stokes parameters similar to the four Stokes parameters used in optical radiative transfer theory. The theory is applied to a statistically homogeneous isotropic half space containing randomly distributed spherical voids illuminated by a harmonic plane wave.","This approach is then extended to continuous polycrystalline media. In this case, because a representative scatterer is not readily identified, the URTE is derived directly from the elastic wave equation and first principles. Appropriate ensemble averaging of the elastic wave equation leads to Dyson and Bethe-Salpeter equations which govern the mean Green's function and the covariance of the Green's function, respectively. These equations are expanded for weak heterogeneity and the URTE obtained. The result is valid for attenuations that are small compared with a wave number. Along with steady-state solutions, results are presented for the time-dependent intensity backscattered from a polycrystalline medium submerged in a water bath and excited with a short burst of ultrasonic energy. It is shown that the radiative transfer solutions approach the appropriate single scattering and diffusion limits one would expect, providing confidence in the proposed model. It is anticipated that this work may be applicable to microstructural characterization through the study of the time, space, ultrasonic frequency, and angular dependence of diffusely scattered ultrasound in elastic media.","Made available in DSpace on 2011-05-07T12:31:35Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9512578.pdf: 5685908 bytes, checksum: e3b731d6abb35328182c77734f1b86c6 (MD5) Previous issue date: 1994","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:42:12Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:18:19-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Radiative transfer of ultrasound"]}]}],"canonical_facts":{"dc:contributor":["Weaver, Richard L."],"dc:creator":["Turner, Joseph Alan"],"dc:date":["2011-05-07T12:31:35Z","10000-01-01","1994"],"dc:description":["Radiative transfer theory is used to model the multiple scattering of diffuse ultrasonic waves in two types of random media. The first type is an isotropic, homogeneous medium containing randomly oriented, randomly located scatterers. The scatterers are assumed to be uncorrelated. This assumption allows an equation of transfer to be written which governs the multiply scattered intensities. This ultrasonic radiative transfer equation (URTE) contains single scattering and propagation parameters that are calculated using the elastic wave equation. Polarization effects are included through the introduction of an elastodynamic Stokes vector which contains a longitudinal Stokes parameter and four shear Stokes parameters similar to the four Stokes parameters used in optical radiative transfer theory. The theory is applied to a statistically homogeneous isotropic half space containing randomly distributed spherical voids illuminated by a harmonic plane wave.","This approach is then extended to continuous polycrystalline media. In this case, because a representative scatterer is not readily identified, the URTE is derived directly from the elastic wave equation and first principles. Appropriate ensemble averaging of the elastic wave equation leads to Dyson and Bethe-Salpeter equations which govern the mean Green's function and the covariance of the Green's function, respectively. These equations are expanded for weak heterogeneity and the URTE obtained. The result is valid for attenuations that are small compared with a wave number. Along with steady-state solutions, results are presented for the time-dependent intensity backscattered from a polycrystalline medium submerged in a water bath and excited with a short burst of ultrasonic energy. It is shown that the radiative transfer solutions approach the appropriate single scattering and diffusion limits one would expect, providing confidence in the proposed model. It is anticipated that this work may be applicable to microstructural characterization through the study of the time, space, ultrasonic frequency, and angular dependence of diffusely scattered ultrasound in elastic media.","Made available in DSpace on 2011-05-07T12:31:35Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9512578.pdf: 5685908 bytes, checksum: e3b731d6abb35328182c77734f1b86c6 (MD5) Previous issue date: 1994","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:42:12Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:18:19-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9512578","(UMI)AAI9512578","http://hdl.handle.net/2142/20186"],"dc:language":["eng"],"dc:rights":["Copyright 1994 Turner, Joseph Alan"],"dc:subject":["Applied Mechanics","Engineering, Materials Science","Physics, Acoustics"],"dc:title":["Radiative transfer of ultrasound"],"dc:type":["text"],"thesis:degree_discipline":["Mechanical Science"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:15Z"}