Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Acoustics (2)
- Acoustical (1)
- Adaptive filtering (1)
- Aircraft (1)
- Architectural acoustics (1)
-
- Archival (1)
- Carbon nanotubes (1)
- Coherence (1)
- Continuous (1)
- Copper (1)
- Correlated (1)
- DIR (1)
- Data storage (1)
- Decomposition (1)
- Dielectrophoresis (1)
- Directional impulse response (1)
- Discrete (1)
- Energy Density (1)
- Energy density (1)
- Energy density equalization (1)
- Equalization (1)
- Equalization history (1)
- Extreme ultraviolet (1)
- Field (1)
- Holography (1)
- Jet (1)
- Least squares (1)
- Length (1)
- Listening test (1)
- Microphones (1)
Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Equalization Of Loudspeakers And Enclosed Sound Fields, Xi Chen
Equalization Of Loudspeakers And Enclosed Sound Fields, Xi Chen
Theses and Dissertations
Equalization of loudspeakers and enclosed sound fields has been a topic of considerable interest for decades. Confusion has often arisen among audio professionals regarding the feasibility of simultaneously equalizing a loudspeaker and the enclosed field (i.e., the “room”) it excites. Because of frustrations encountered in such efforts, some have advocated abandoning simultaneous equalization altogether. This dissertation discusses the drawbacks of this approach as well as traditional in situ equalization methods. It demonstrates that many problems with traditional equalization stem from the use of measured acoustic pressure at a discrete point in a sound field as the system output. The dissertation …
Carbon Coated Tellurium For Optical Data Storage, Jonathan D. Abbott
Carbon Coated Tellurium For Optical Data Storage, Jonathan D. Abbott
Theses and Dissertations
A highly durable optical disk has been developed for data archiving. This optical disk uses tellurium as the write layer and carbon as a dielectric and oxidation prevention layer. The sandwich style CTeC film was deposited on polycarbonate and silicon substrates by plasma sputtering. These films were then characterized with SEM, TEM, EELS, ellipsometry, ToF-SIMS, etc, and were tested for writability and longevity. Results show the films were uniform in physical structure, are stable, and able to form permanent pits. Data was written to a disk and successfully read back in a commercial DVD drive.
Development And Comparison Of Methods For Measuring Directional Sound Arrivals In Rooms, Brian Trevor Thornock
Development And Comparison Of Methods For Measuring Directional Sound Arrivals In Rooms, Brian Trevor Thornock
Theses and Dissertations
In room acoustics, the directional information of sound arrivals at a listening location can be used to diagnose the origins of problematic reflections so offending surfaces or other features can be properly treated. It can also be used for other purposes, including the study of psychoacoustic indicators. Many methods have been developed in the past to derive directional information, but despite their benefits, each has had significant drawbacks that have necessitated further research into their properties and development of an improved method. This thesis presents a review of past methods, their benefits and shortcomings. It discusses many theoretical and practical …
Scan-Based Near-Field Acoustical Holography On Partially Correlated Sources, Michael D. Gardner
Scan-Based Near-Field Acoustical Holography On Partially Correlated Sources, Michael D. Gardner
Theses and Dissertations
Scan-based near-field acoustical holography (NAH) is applied to partially correlated sources. Partial field decomposition via the virtual coherence method is used to implement the scan-based NAH. The background and theory of these methods are developed. Multiple stationary reference microphones are required for the partial field decomposition. Guidelines for reference microphone placement in the literature thus far have been limited. Improved guidelines for reference microphones are given after the results of two sets of experiments. The first set involves discrete, partially correlated sources, both physical and numerical. The second set of experiments is strictly numerical and involves continuous sources. Fewer microphones …
Massively Parallel Indirect Dielectrophoresis Controlled Placement Of Carbon Nanotubes, Hiram Jacob Conley
Massively Parallel Indirect Dielectrophoresis Controlled Placement Of Carbon Nanotubes, Hiram Jacob Conley
Theses and Dissertations
Placement of single walled carbon nanotubes is demonstrated through massively parallel indirect dielectrophoresis (MPID). MPID is shown to be able to control the placement of carbon tubes as well as the number of tubes placed. Lumped element analysis for AC circuits is used to model MPID. This model allows for predictions of the number of tubes that will be captured in a trap. This model has been consistent with experimental data of numbers of nanotube placed in a junction. Carbon nanotubes placed with MPID are shown to be electrically active.
Extreme Ultraviolet Polarimetry With Laser-Generated High-Order Harmonics: Characterization Of Uranium, Nicole Brimhall
Extreme Ultraviolet Polarimetry With Laser-Generated High-Order Harmonics: Characterization Of Uranium, Nicole Brimhall
Theses and Dissertations
We developed an extreme ultraviolet (EUV) polarimeter, which employs laser-generated high-order harmonics as the light source. This relatively high-flux, directional EUV source has available wavelengths between 10 nm and 47 nm with easily rotatable linear polarization. The polarimeter has allowed us to characterize the optical constants of materials that may be useful for EUV optics. The instrument has a versatile positioning system and a spectral resolution of about 180, and we have demonstrated that reflectance as low as 0.1% can be measured repeatably at EUV wavelengths. We investigate the high harmonic source used for polarimetry measurements by documenting the spatial …
Development Of An Adaptive Equalization Algorithm Using Acoustic Energy Density, Panu Tapani Puikkonen
Development Of An Adaptive Equalization Algorithm Using Acoustic Energy Density, Panu Tapani Puikkonen
Theses and Dissertations
Sound pressure equalization of audio signals using digital signal processors has been a subject of ongoing study for many years. The traditional approach is to equalize sound at a point in a listening environment, but because of its specific dependence on the room frequency response between a source and receiver position, this equalization generally causes the spectral response to worsen significantly at other locations in the room. This work presents both a time-invariant and a time-varying implementation of an adaptive acoustic energy density equalization filter for a one-dimensional sound field. Energy density equalization addresses the aforementioned challenge and others that …