Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 97 for “"pressure level"”.
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Support vs. Steady Airflow: The Effect of Two Different Instructions on Subglottal Pressure, Sound Pressure Level, and Airflow Rate during Singing and Speaking
… that the word promotes the use of increased air pressure. The purpose of the present investigation was to test that hypothesis by examining differences in a variety of physiological parameters, comparing a conventional singing instruction that uses the word “support” with an alternative …
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A turbulent combustion noise model
… in this thesis. The model predicts (1) the pressure time series, (2) Sound Pressure Level (SPL) spectrum, (3) Over-All Sound Pressure Level (OASPL), (4) the thermoacoustic efficiency, (5) the peak frequency, and (6) the sound power of combustion generated noise. In addition, a correlation …
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Anomaly detection for environmental noise monitoring
Octave-band sound pressure level is the preferred measure for continuous environmental noise monitoring over raw audio because accepted standards and devices exist, these data do not compromise voice privacy, and thus an octave-band sound meter can legally collect data in public. By setting up an …
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Aerodynamic and Acoustic Modeling for eVTOL Rotor Noise Prediction
… variations in tonal blade-passing-frequency levels at 4000 revolutions per minute (RPM) and broadband spectral differences of approximately 4 dB. Despite these spectral variations, integrated overall sound pressure level predictions show limited sensitivity to turbulence model choice. At 2000 …
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Comfort studies on aircraft interior sound and vibration
… situations were systematically varied in sound pressure level and vibration magnitude (3 x 3 design) and implemented as stimuli in the second experimental study using a 'sound and vibration reproduction system'. Thirty subjects using the same SD assessed each configuration. Analyses of variance …
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Changes of voice production in artificial acoustic environments
The physical production of speech level dynamic range is directly affected by the physiological features of the speaker such as vocal tract size and lung capacity. However, the regulation of these production systems is affected by the perception of the communication environment and auditory …
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A Unified Measure of Audio System Fidelity
… distortion as a function of the perceived Sound Pressure Level (SPL).
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A measurement method for damping of drive shaft
… and governments. For a truck the sound pressure level should not exceed 80 dB(A) during a drive-by test set by international standards. This leads to development of the noise for the truck, and different parts get their own allowed component noise level. This thesis will look at one of …
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Noise Levels in a South African bank cash centre
… within the cash centres are exposed to noise levels that could be damaging to the auditory system and warrants the implementation of a hearing conservation programme. In order to investigate the noise levels emitted during cash management processes, the researcher obtained noise level …
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Pressure-Based Interaction Techniques for Supporting Feedback Strategies in Sports
This thesis provides evidence for the use of pressure-based input to facilitate the provision of in-situ performance information in extreme Human Computer Interaction scenarios. In such scenarios there is a risk that providing more information to the user would increase workload, be distracting and …
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The Role of Situational and Dispositional Factors on Sub-Optimal Performance
Pressure is known to decrease performance for well-practiced tasks. Research has found that pressure decreases performance for those with high self-consciousness when distracted, but the effects of pressure and distraction are not known for those with low self-consciousness. Therefore, the purpose …
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Effects of Mechanical Forces on the Biological Properties of Porcine Aortic Valve Leaflets
… Altered mechanical stresses, including pressure, shear and bending stresses, are believed to cause changes in valve biology, but the cellular and molecular events involved in these processes are not well characterized. Therefore, the overall goal of this project is to determine the …
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Characterizing The Acoustic Properties Of The Jet Lab At The National Center For Physical Acoustics
… at each frequency to calculate the sound pressure level and determine if the calculated values are within the allotolerance of the inverse square law.
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The Effects of Divided Attention on Speech Motor, Verbal Fluency and Manual Motor Task Performance
… and peak velocity decreased, while sound pressure level and spatiotemporal variability increased. The impact of manual motor performance on speech differed between the right and left hand. Manual motor scores significantly decreased when concurrently performed with the verbal fluency task. …
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Computer assisted audiometric evaluation system
… microphone eliminates the need for a sound pressure level meter during speech tests. The software-based user-interface makes use.of overlaid pop-up menus, context sensitive assistance.and a text editor on a graphics screen. Pure tone and speech data are acquired and displayed on a dynamic …
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Experimental measurement of combustion noise and comparison to a predictive model
… The data are presented in the form of acoustic pressure spectra and over-all sound pressure levels. The experiment consisted of a geometrically simple pre-mixed burner with five interchangeable nozzles whose diameters varied from 0.117 cm to 0.541 cm. The fuels examined in the experiment were …
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Experimental investigation of the flow field during combustion in narrow circular ducts
… wave propagation analysis also yielded a sound pressure level consistent with audio perception during flame oscillations with acoustic emissions.
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Toward a micro-scale acoustic direction-finding sensor with integrated electronic readout
… can be exposed to at least 162 decibel sound pressure level with no loss of function. Next, an improved capacitive readout system using branched comb fingers is presented. This design is shown to double electrical sensitivity to motion. Finally, it is shown that residual stress-induced …
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Implementation of Refractory Foam Technology for Silencing Small IC Engines
… areas of noise reduction, weight, size, and backpressure, compared to commercial designs. The final silencer design boasted an Aweighted overall sound pressure level that was 12.1 dBA lower than the reference case. This result was accomplished using nearly half the volume required by other …
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Numerical Analysis of Gun Barrel Pressure Blast Using Dynamic Mesh Adaption
… (CFD) method has been applied to simulate the pressure blast of the projectile which is launched from a barrel and to investigate the pressure distribution and sound pressure level (dB) along different positions away from the gun axis and towards the fuselage of the aircraft. Fluent was …
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