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Full-Text Articles in Acoustics, Dynamics, and Controls

Laser-Assisted Sound Source Localization Inside A Solid Enclosure, Antonio Figueroa Mombela Jan 2022

Laser-Assisted Sound Source Localization Inside A Solid Enclosure, Antonio Figueroa Mombela

Wayne State University Dissertations

Sound source localization is typically conducted in open space so that the line of sight is not blocked among individual sensors. This research presents a new technology that enables one to see acoustically through a solid Plexiglass enclosure to locate a sound source stationed inside at some arbitrarily selected locations. By using SODAR technology, non-invasive laser-assisted microphones, analog, and digital signal processing (band-pass filtering, fast Fourier transform algorithm, cross-correlations, and triangulations) satisfactory sound source localization results were obtained. In this project, the enclosure walls were flat; only the azimuth angle of a sound source could be determined. To obtain the …


Development Of The Carbon Nanotube Thermoacoustic Loudspeaker, Troy Bouman Jan 2021

Development Of The Carbon Nanotube Thermoacoustic Loudspeaker, Troy Bouman

Dissertations, Master's Theses and Master's Reports

Traditional speakers make sound by attaching a coil to a cone and moving that coil back and forth in a magnetic field (aka moving coil loudspeakers). The physics behind how to generate sound via this velocity boundary condition has largely been unchanged for over a hundred years. Interestingly, around the time moving coil loudspeakers were first investigated the idea of using heat to generate sound was also known. These thermoacoustic speakers heat and cool a thin material at acoustic frequencies to generate the pressure wave (i.e. they use a thermal boundary condition). Unfortunately, when the thermoacoustic principle was initially discovered …


Less Commute Miles. Decreased Tire Wear. What Would You Do?, Dylan Schwarz, Brendon M. Ford, Brandon D. Hadinger, Abbie N. Pearce, Jacinta M. Pikunas Jan 2021

Less Commute Miles. Decreased Tire Wear. What Would You Do?, Dylan Schwarz, Brendon M. Ford, Brandon D. Hadinger, Abbie N. Pearce, Jacinta M. Pikunas

Williams Honors College, Honors Research Projects

With the flagrant recognition of the coronavirus as one of those most impactful viruses in the history of the world, it is important to study how the effects of such a disease can create troublesome ripple effects in the world. Covid-19 has caused the death of hundreds of thousands of individuals and has negatively impacted the lives of American’s all across the country during the nationwide lockdown. Decreased work commuters, minimal road travel, and little need for car repairs hit the Goodyear Tire and Rubber Company hard. The University of Akron has teamed up with Goodyear to explore such effects …


Less-Than-Lethal Self Defense Device With An Acoustic Element, Anthony Taibi Apr 2019

Less-Than-Lethal Self Defense Device With An Acoustic Element, Anthony Taibi

KSU Journey Honors College Capstones and Theses

This creative capstone project involves the conception, design, and creation of a less-than-lethal self defense device with an integrated sound board to control the acoustic element. Theoretically, this device is capable of deterring potential threats without causing any serious harm or any long-term damage. When starting this project, I was very focused on sonic warfare, and how to harness the power of ultrasonic and infrasonic sound waves to subdue to target; however, I concluded that using resonant frequencies to deter a human being is too dangerous, expensive, and can have negative effects for the user of the device if used …


Improved Low-Frequency Impact Insulation Class Measurements Based On Comparison Techniques, Sunit Girdhar Jan 2019

Improved Low-Frequency Impact Insulation Class Measurements Based On Comparison Techniques, Sunit Girdhar

Dissertations, Master's Theses and Master's Reports

In today’s world, noise pollution is growing as a major concern and it is becoming more and more difficult to find quiet places. But when the problem escalates to the extent that people are annoyed with loud noises even in their apartments, it becomes an alarming issue for engineers. Around the world, cities have defined some basic performance requirements for buildings, and isolation of residents from noise is one of the cardinal performance requirements. In the United States, building codes use the Impact Insulation Class (IIC) rating to characterize the performance of floor/ceiling assemblies. This method uses the response measured …


A Bioinspired Modification For Uas Propeller/Rotor Noise Reduction, Mark N. Callender Oct 2016

A Bioinspired Modification For Uas Propeller/Rotor Noise Reduction, Mark N. Callender

ASA Multidisciplinary Research Symposium

This projects presents a bioinspired modification to UAS propellers/rotors for noise reduction. Sound pressure levels (SPL) and thrust for modified propellers were compared to a baseline propeller. The bioinspired modification yielded lower SPL with a requisite increase in rpm in order to maintain a chosen level of thrust.


Effect Of Compression On The Transmission Loss Of Porous Material, Yingchao Yang, J Stuart Bolton Oct 2013

Effect Of Compression On The Transmission Loss Of Porous Material, Yingchao Yang, J Stuart Bolton

The Summer Undergraduate Research Fellowship (SURF) Symposium

Porous materials are commonly applied in sound absorption in different places. Transmission loss, one of the vital parameters determining the performance of the material, will change when the material is compressed. Usually the compression that might affect the properties to the greatest extent are normal compression and the deformation can be simplified as 1D compression model. In order to verify the prediction, some formulas taking several parameters (porosity, tortuosity, flow resistivity and characteristic lengths) into account are applied and also the Johnson et al’s model of limp structure. Dynamic density of limp model and bulk modulus are thus obtained and …


Developing A System For Blind Acoustic Source Localization And Separation, Raghavendra Kulkarni Jan 2013

Developing A System For Blind Acoustic Source Localization And Separation, Raghavendra Kulkarni

Wayne State University Theses

This dissertation presents innovate methodologies for locating, extracting, and separating multiple incoherent sound sources in three-dimensional (3D) space; and applications of the time reversal (TR) algorithm to pinpoint the hyper active neural activities inside the brain auditory structure that are correlated to the tinnitus pathology. Specifically, an acoustic modeling based method is developed for locating arbitrary and incoherent sound sources in 3D space in real time by using a minimal number of microphones, and the Point Source Separation (PSS) method is developed for extracting target signals from directly measured mixed signals. Combining these two approaches leads to a novel technology …