{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/108218"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/108218","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Topics in diffuse field ultrasonics","abstract":"Random wave fields that have explored large volumes over long times contain much information. Studying these diffuse fields and extracting the information contained in them are the primary aims of Diffuse Field Theory. When the waves of interest are elastic waves at frequencies above 20kHz, the subject can be called Diffuse Field Ultrasonics. Here, three topics of Diffuse Field Ultrasonics are presented. The first concerns the identification of the Green’s function with the cross-correlation produced from a diffuse wave field. This has been termed Green’s Function Retrieval. Of particular concern is the accurate retrieval of amplitude when the wave field fails to be fully diffuse. The second topic involves the study of diffuse fields in nearly axisymmetric elastic bodies. The distribution of energy within such a body and subsequent transport is predicted and then compared with experimental measurements on an aluminum cylinder with a hole in its side. Appeals to Enhanced Backscatter and Dynamical Anderson Localization are needed for full agreement of theory and experiment. The third topic is Slow Dynamics, a remarkable non-classical nonlinear elastic behavior found in a wide-range of materials that possess a cracked microstructure and at various length scales. Two new experimental venues and a variety of preliminary studies are presented in the hope of elucidating the micro-physics behind slow dynamics. Before discussing these three topics, the concept of a diffuse field is introduced. The conclusion summarizes the central results of each preceding chapter.","abstract_html":"Random wave fields that have explored large volumes over long times contain much information. Studying these diffuse fields and extracting the information contained in them are the primary aims of Diffuse Field Theory. When the waves of interest are elastic waves at frequencies above 20kHz, the subject can be called Diffuse Field Ultrasonics. Here, three topics of Diffuse Field Ultrasonics are presented. The first concerns the identification of the Green’s function with the cross-correlation produced from a diffuse wave field. This has been termed Green’s Function Retrieval. Of particular concern is the accurate retrieval of amplitude when the wave field fails to be fully diffuse. The second topic involves the study of diffuse fields in nearly axisymmetric elastic bodies. The distribution of energy within such a body and subsequent transport is predicted and then compared with experimental measurements on an aluminum cylinder with a hole in its side. Appeals to Enhanced Backscatter and Dynamical Anderson Localization are needed for full agreement of theory and experiment. The third topic is Slow Dynamics, a remarkable non-classical nonlinear elastic behavior found in a wide-range of materials that possess a cracked microstructure and at various length scales. Two new experimental venues and a variety of preliminary studies are presented in the hope of elucidating the micro-physics behind slow dynamics. Before discussing these three topics, the concept of a diffuse field is introduced. The conclusion summarizes the central results of each preceding chapter.","abstract_has_math":false,"creators":["Yoritomo, John Yukio"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Weaver, Richard L","Dahmen, Karin","Popovics, John","Grosse Perdekamp, Matthias"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-08-27T00:46:47Z","date_published":"2020-08-27T00:46:47Z","updated_at":"2026-07-22T22:24:48Z","subjects":["Ultrasonics","Acoustics","Physical Acoustics","Elastodynamics","Elastic Waves","Diffuse fields","Diffuse field theory","Diffuse field ultrasonics","diffuse ultrasound","Wave physics","Green's function retrieval","seismic interferometry","passive imaging","spurious arrivals","enhanced backscatter","dynamical Anderson localization","dynamical localization","axisymmetric elastic bodies","slow dynamics","slow dynamic nonlinearity","non-classical nonlinear elasticity","nonlinear acoustics","coda wave interferometry","granular media","resonant transmission","glass bead packs","thermal activation"],"languages":["en"],"rights":["Copyright 2020 John Y. Yoritomo. All rights reserved."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/108218","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Weaver, Richard L","Dahmen, Karin","Popovics, John","Grosse Perdekamp, Matthias"]},{"key":"dc:creator","label":"Author","values":["Yoritomo, John Yukio"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-08-27T00:46:47Z","2022-08-27T00:51:40Z","2020-01-29","2020-05"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"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":["Ultrasonics","Acoustics","Physical Acoustics","Elastodynamics","Elastic Waves","Diffuse fields","Diffuse field theory","Diffuse field ultrasonics","diffuse ultrasound","Wave physics","Green's function retrieval","seismic interferometry","passive imaging","spurious arrivals","enhanced backscatter","dynamical Anderson localization","dynamical localization","axisymmetric elastic bodies","slow dynamics","slow dynamic nonlinearity","non-classical nonlinear elasticity","nonlinear acoustics","coda wave interferometry","granular media","resonant transmission","glass bead packs","thermal activation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2020 John Y. 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The second topic involves the study of diffuse fields in nearly axisymmetric elastic bodies. The distribution of energy within such a body and subsequent transport is predicted and then compared with experimental measurements on an aluminum cylinder with a hole in its side. Appeals to Enhanced Backscatter and Dynamical Anderson Localization are needed for full agreement of theory and experiment. The third topic is Slow Dynamics, a remarkable non-classical nonlinear elastic behavior found in a wide-range of materials that possess a cracked microstructure and at various length scales. Two new experimental venues and a variety of preliminary studies are presented in the hope of elucidating the micro-physics behind slow dynamics. Before discussing these three topics, the concept of a diffuse field is introduced. The conclusion summarizes the central results of each preceding chapter.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-05-01","The student, John Yoritomo, accepted the attached license on 2020-01-29 at 09:31.","The student, John Yoritomo, submitted this Dissertation for approval on 2020-01-29 at 09:36.","This Dissertation was approved for publication on 2020-01-29 at 13:53.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14859 on 2020-08-25 at 17:38:27","Made available in DSpace on 2020-08-27T00:46:47Z (GMT). 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Studying these diffuse fields and extracting the information contained in them are the primary aims of Diffuse Field Theory. When the waves of interest are elastic waves at frequencies above 20kHz, the subject can be called Diffuse Field Ultrasonics. Here, three topics of Diffuse Field Ultrasonics are presented. The first concerns the identification of the Green’s function with the cross-correlation produced from a diffuse wave field. This has been termed Green’s Function Retrieval. Of particular concern is the accurate retrieval of amplitude when the wave field fails to be fully diffuse. The second topic involves the study of diffuse fields in nearly axisymmetric elastic bodies. The distribution of energy within such a body and subsequent transport is predicted and then compared with experimental measurements on an aluminum cylinder with a hole in its side. Appeals to Enhanced Backscatter and Dynamical Anderson Localization are needed for full agreement of theory and experiment. The third topic is Slow Dynamics, a remarkable non-classical nonlinear elastic behavior found in a wide-range of materials that possess a cracked microstructure and at various length scales. Two new experimental venues and a variety of preliminary studies are presented in the hope of elucidating the micro-physics behind slow dynamics. Before discussing these three topics, the concept of a diffuse field is introduced. The conclusion summarizes the central results of each preceding chapter.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-05-01","The student, John Yoritomo, accepted the attached license on 2020-01-29 at 09:31.","The student, John Yoritomo, submitted this Dissertation for approval on 2020-01-29 at 09:36.","This Dissertation was approved for publication on 2020-01-29 at 13:53.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14859 on 2020-08-25 at 17:38:27","Made available in DSpace on 2020-08-27T00:46:47Z (GMT). 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Yoritomo. All rights reserved."],"dc:subject":["Ultrasonics","Acoustics","Physical Acoustics","Elastodynamics","Elastic Waves","Diffuse fields","Diffuse field theory","Diffuse field ultrasonics","diffuse ultrasound","Wave physics","Green's function retrieval","seismic interferometry","passive imaging","spurious arrivals","enhanced backscatter","dynamical Anderson localization","dynamical localization","axisymmetric elastic bodies","slow dynamics","slow dynamic nonlinearity","non-classical nonlinear elasticity","nonlinear acoustics","coda wave interferometry","granular media","resonant transmission","glass bead packs","thermal activation"],"dc:title":["Topics in diffuse field ultrasonics"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:48Z"}