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in subjects: "Acoustics"

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Suppression of Higher Acoustic Harmonics by Application of Solid-Solid Periodic Layered Structure in Nonlinear Ultrasonics Nondestructive Evaluation Field

Nondestructive testing (NDT) using ultrasound band 1-5 MHz, has been widely used for the early-stage detection of structural failure; however, it fails to detectf material degradation, fatigue, and microcracks. NDT with nonlinear ultrasound (NLU) can detect a microscopic discontinuity or imperfection that may be a source of the second harmonic in the reflected signal. In this research, we focus on creating a metamaterial band filter that filters out nonlinearities induced by the instrument itse… more

Date: May 2023

Creator: Kang, Jinho

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Tuning the decay of sound in a viscous metamaterial

Authors of the article use analytical results for viscous dissipation in phononic crystals to calculate the decay coefficient of a sound wave propagating at low frequencies through a two-dimensional phononic crystal with a viscous fluid background. They claim that the decay coefficient exhibits dependence on the direction of propagation; that is, a homogenized phononic crystal behaves like an anisotropic viscous fluid.

Date: October 10, 2022

Creator: Ibarias, M.; Doporto, J.; Krokhin, Arkadii A. & Arriaga, J.

Item Type: Article

Partner: UNT College of Science

Remotely Controlled Magneto-Phononic Devices Achieving Nonreciprocity and Anderson Localization in Ferrofluid

Motivated by previous relevant research on phononics including both active and passive phononics, the interest of faster turnability and more functions of the active phononics of further study led to this proposing research topic: magnetic field tunable active functional phononics. The first design of magnetic field tunable reciprocal--non-reciprocal transmission acoustic device was established, material was characterized, and numerical simulation has been performed. The simulation results show… more

Date: December 2021

Creator: Jin, Yuqi

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Longitudinal Monostatic Acoustic Effective Bulk Modulus and Effective Density Evaluation of Underground Soil Quality: A Numerical Approach

This article introduces a novel method using longitudinal sound to detect underground soil voids to inspect underwater bed property in terms of effective bulk modulus and effective density of the material properties.

Date: December 25, 2020

Creator: Jin, Yuqi; Choi, Tae-Youl & Neogi, Arup

Item Type: Article

Partner: University of North Texas

open access

Sub-wavelength lateral detection of tissue-approximating masses using an ultrasonic metamaterial lens

Article demonstrating a phononic metamaterial lens (ML) for detection of laterally subwavelength object features in tissue-like phantoms beyond the phononic crystal evanescent zone and Fresnel zone of the emitter.

Date: November 24, 2020

Creator: Walker, Ezekiel; Jin, Yuqi; Reyes, Delfino & Neogi, Arup

Item Type: Article

Partner: UNT College of Science

open access

Long-range nonspreading propagation of sound beam through periodic layered structure

Article analyzing dispersion of sound in a solid-fluid layered structure and found a flex point on the isofrequency curve where D vanishes for given direction of propagation and frequency. Nonspreading propagation is experimentally observed in a water steel lattice of 75 periods (~1 meter long) and occurs in the regime of anomalous dispersion and strong acoustic anisotropy when the effective mass along periodicity is close to zero. Under these conditions the incoming beam experiences negative r… more

Date: September 2, 2020

Creator: Zubov, Yurii; Djafari-Rouhani, Bahram; Jin, Yuqi; Sofield, Mathew; Walker, Ezekiel; Neogi, Arup et al.

Item Type: Article

Partner: UNT College of Science

open access

An acoustic analysis of American English liquids by adults and children: Native English speakers and native Japanese speakers of English

This article is a study investigating acoustic characteristics of American English liquids produced by native English (NE) and native Japanese (NJ) speakers reported in Aoyama, Flege, Guion, Akahane-Yamada, and Yamada [(2004). J. Phonetics 32, 233–250]. The secondary aim of the study is to compare the acoustic nature of English liquids between native speakers and Japanese L2 speakers of English. This work was presented at the 170th Meeting of the Acoustical Society of America on June 25, 2017 i… more

Date: October 24, 2019

Creator: Aoyama, Katsura; Flege, James E.; Akahane-Yamada, Reiko & Yamada, Tsuneo

Item Type: Article

Partner: UNT College of Health and Public Service

open access

Physical Boundary as a Source of Anomalies in Transport Processes in Acoustics and Electrodynamics

Various anomalous effects that emerge when the interfaces between media are involved in sound-matter or light-matter interactions are studied. The three specific systems examined are a fluid channel between elastic metal plates, a linear chain of metallic perforated cylindrical shells in air, and a metal-dielectric slab with the interfaces treated as finite regions of smoothly changing material properties. The scattering of acoustic signals on the first two is predicted to be accompanied by the… more

Date: December 2018

Creator: Bozhko, Andrii

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Baseline Bioacoustic Characterization for Offshore Renewable Energy Development in the North Carolina and Georgia Wind Planning Areas

This is a study on technologies developments for harnessing energy from the ocean environment. Technological improvements in offshore renewable energy like wind and hydrokinetic captured energy. Passive acoustics allow researchers to analyze how the construction and use of such technologies affect marine species.

Date: January 2015

Creator: Rice, Aaron N.; Morano, Janelle L.; Hodge, Kristin B.; Muirhead, Charles A.; Frankel, Adam S.; Feinblatt, Michael et al.

Item Type: Text

Partner: UNT Libraries Government Documents Department

open access

Structural, Thermal and Acoustic Performance of Polyurethane Foams for Green Buildings

Decreasing the carbon footprint through use of renewable materials has environmental and societal impact. Foams are a valuable constituent in buildings by themselves or as a core in sandwich composites. Kenaf is a Southeast USA plant that provides renewable filler. The core of the kenaf is porous with a cell size in a 5-10 micrometer range. The use of kenaf core in foams represents a novel multiscalar cellular structural composite. Rigid polyurethane foams were made using free foaming expansion… more

Date: December 2014

Creator: Nar, Mangesh

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Electromagnetically Modulated Sonic Structures

Phononic crystals are structures composed of periodically arranged scatterers in a background medium that affect the transmission of elastic waves. They have garnered much interest in recent years for their macro-scale properties that can be modulated by the micro-scale components. The elastic properties of the composite materials, the contrast in the elastic properties of the composite materials, and the material arrangement all directly affect how an elastic wave will behave as it propagates … more

Date: May 2014

Creator: Walker, Ezekiel Lee

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

2012 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

This Research is about Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies which presents a preliminary model of the three-dimensional seismic structure of the Iran region.

Date: September 10, 2012

Creator: Wetovsky, Marvin A.; Anderson, Dale; Arrowsmith, Stephen J.; Begnaud, Michael L.; Hartse, Hans E.; Maceira, Monica et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Raising Photoemission Efficiency with Surface Acoustic Waves

We are developing a novel technique that may help increase the efficiency and reduce costs of photoelectron sources used at electron accelerators. The technique is based on the use of Surface Acoustic Waves (SAW) in piezoelectric materials, such as GaAs, that are commonly used as photocathodes. Piezoelectric fields produced by the traveling SAW spatially separate electrons and holes, reducing their probability of recombination, thereby enhancing the photoemission quantum efficiency of the photo… more

Date: July 1, 2012

Creator: A. Afanasev, F. Hassani, C.E. Korman, V.G. Dudnikov, R.P. Johnson, M. Poelker, K.E.L. Surles-Law

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The BigBoss Experiment

BigBOSS is a Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with a wide-area galaxy and quasar redshift survey over 14,000 square degrees. It has been conditionally accepted by NOAO in response to a call for major new instrumentation and a high-impact science program for the 4-m Mayall telescope at Kitt Peak. The BigBOSS instrument is a robotically-actuated, fiber-fed spectrograph capable of taking 5000 simultaneous spectra o… more

Date: June 7, 2012

Creator: Schelgel, D.; Abdalla, F.; Abraham, T.; Ahn, C.; Allende Prieto, C.; Annis, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effects of Dissipation on Propagation of Surface Electromagnetic and Acoustic Waves

With the recent emergence of the field of metamaterials, the study of subwavelength propagation of plane waves and the dissipation of their energy either in the form of Joule losses in the case of electomagnetic waves or in the form of viscous dissipation in the case of acoustic waves in different interfaced media assumes great importance. with this motivation, I have worked on problems in two different areas, viz., plasmonics and surface acoustics. the first part (chapters 2 & 3) of the disser… more

Date: May 2012

Creator: Nagaraj, Nagaraj

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Final Report

The purpose of this project was to better understand the 'Multiscale Dynamics of Relaxor Ferroelectrics'. The output of the project is summarized in the narrative. The results of the work were presented at a number of different conferences and four papers were written, the references to which are also indicated in the report and which have also been uploaded on e-link. The multiscale dynamics of relaxors was clearly identified in the three characteristic temperatures that were identified. In pa… more

Date: April 5, 2012

Creator: Toulouse, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Acoustic Imaging Evaluation of Juvenile Salmonid Behavior in the Immediate Forebay of the Water Temperature Control Tower at Cougar Dam, 2010

This report presents the results of an evaluation of juvenile Chinook salmon (Oncorhynchus tshawytscha) behavior at Cougar Dam on the south fork of the McKenzie River in Oregon in 2010. The study was conducted by the Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers (USACE). The overall goal of the study was to characterize juvenile salmonid behavior and movement patterns in the immediate forebay of the Water Temperature Control (WTC) tower of the dam for USACE and fish… more

Date: April 1, 2012

Creator: Khan, Fenton; Johnson, Gary E.; Royer, Ida M.; Phillips, Nathan RJ; Hughes, James S.; Fischer, Eric S. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Study of the Acoustic Effects of Hydrokinetic Tidal Turbines in Admiralty Inlet, Puget Sound

Hydrokinetic turbines will be a source of noise in the marine environment - both during operation and during installation/removal. High intensity sound can cause injury or behavioral changes in marine mammals and may also affect fish and invertebrates. These noise effects are, however, highly dependent on the individual marine animals; the intensity, frequency, and duration of the sound; and context in which the sound is received. In other words, production of sound is a necessary, but not suff… more

Date: March 30, 2012

Creator: Polagye, Brian; Thomson, Jim; Bassett, Chris; Wood, Jason; Tollit, Dom; Cavagnaro, Robert et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Passive Acoustic Detection of Wind Turbine In-Flow Conditions for Active Control and Optimization

Wind is a significant source of energy; however, the human capability to produce electrical energy still has many hurdles to overcome. One of these is the unpredictability of the winds in the atmospheric boundary layer (ABL). The ABL is highly turbulent in both stable and unstable conditions (based on the vertical temperature profile) and the resulting fluctuations can have a dramatic impact on wind turbine operation. Any method by which these fluctuations could be observed, estimated, or predi… more

Date: March 12, 2012

Creator: Murray, Nathan E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Surface photovoltage measurements and finite element modeling of SAW devices.

Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined succe… more

Date: March 1, 2012

Creator: Donnelly, Christine

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Determine the Influence of Time Held in “Knockdown” Anesthesia on Survival and Stress of Surgically Implanted Juvenile Salmonids

The Juvenile Salmon Acoustic Telemetry System (JSATS) was developed for the U.S. Army Corp of Engineers Portland District (USACE) to address questions related to survival and performance measures of juvenile salmonids as they pass through the Federal Columbia River Power System (FCRPS). Researchers using JSATS acoustic transmitters (ATs) were tasked with standardizing the surgical implantation procedure to ensure that the stressors of handling and surgery on salmonids were consistent and less l… more

Date: January 31, 2012

Creator: Woodley, Christa M.; Wagner, Katie A. & Knox, Kasey M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Cleareye In-Ground and In-Concrete DIV Inspections: FY11 Final Report

This report summarizes the results of a series of feasibility testing studies for in-ground and in-concrete imaging/detection technologies including radar imaging and acoustic time-of flight method. The objectives of this project are: (1) Design Information Verification (DIV) Tools for In-Concrete Inspections - To determine the feasibility of using holographic radar imaging (HRI), radar imaging, and acoustic time-of-flight (TOF) non-destructive evaluation technologies to detect, locate and iden… more

Date: January 23, 2012

Creator: Braatz, Brett G.; Tedeschi, Jonathan R.; Denslow, Kayte M.; Morra, Marino; Knopik, Clint D.; Severtsen, Ronald H. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

PASSIVE DETECTION OF VEHICLE LOADING

The Digital Imaging and Remote Sensing Laboratory (DIRS) at the Rochester Institute of Technology, along with the Savannah River National Laboratory is investigating passive methods to quantify vehicle loading. The research described in this paper investigates multiple vehicle indicators including brake temperature, tire temperature, engine temperature, acceleration and deceleration rates, engine acoustics, suspension response, tire deformation and vibrational response. Our investigation into t… more

Date: January 3, 2012

Creator: Garrett, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Integrated Reflection Seismic Monitoring and Reservoir Modeling for Geologic CO2 Sequestration

The US DOE/NETL CCS MVA program funded a project with Fusion Petroleum Technologies Inc. (now SIGMA) to model the proof of concept of using sparse seismic data in the monitoring of CO{sub 2} injected into saline aquifers. The goal of the project was to develop and demonstrate an active source reflection seismic imaging strategy based on deployment of spatially sparse surface seismic arrays. The primary objective was to test the feasibility of sparse seismic array systems to monitor the CO{sub 2… more

Date: December 31, 2011

Creator: Rogers, John

Item Type: Report

Partner: UNT Libraries Government Documents Department