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.
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Showing 1 to 20 of 49 for “"Phase-lag"”.
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An Investigation of Performance Limitations in Active Noise Reduction Headsets
… noise reduction (ANR) headset is limited by phase lag. Speaker dynamics, control hardware, and acoustic wave propagation from the control speaker to the error microphone all contribute to this phase lag. Understanding these sources of phase lag and their relative effects on performance allows …
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Αριθμητική επίλυση συνήθων διαφορικών εξισώσεων με περιοδική λύση
… Afterwards, explicit and implicit methods with phase-lag of order six and eight, a part of which are P-stable while the rest have a larger interval of periodicity than the corresponding classical ones, are being expounded. These methods do not require the a priori knowledge of the frequency of …
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Measurement of combustion response to transverse modes at high pressure
… were fixed across the series of tests. ^ Phase lag data between pressure measurement locations support a simple linear post-to-chamber interaction mechanism. Phase lags between chamber measurements were unaffected by the change in oxidizer post length. Scaling was established between …
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Automatic Guidance of Agricultural Vehicles at Higher Speeds
… rearward to a more practical location added phase lag to the system, and guidance control was less effective.
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The Effects of Different Auditory Feedback Conditions on Speech Rate and Self-Perceptions of Speech
… of speech in non-stutterers, 2) amplified phase-lagged fundamental frequency feedback affects rate and self-perceptions of speech differently than DAF and masking in non-stutterers, and 3) amount of phase-lag in the fundamental frequency feedback linearly relates to the amount of speech …
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System architecture for mode-matching a MEMS gyroscope
… as quadrature error and is used to track the phase across the gyroscope's accelerometer. At mode-match, the phase lag is 90°, so the feedback mechanism maintains this 90° of phase lag between the input acceleration and mechanical output to keep the modes matched. Two controllers were tried in …
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Refractive error, ocular biometry and oculomotor function: The prevalence of myopia and its potential risk factors in the Middle East, with an investigation of dynamic accommodation responses and axial length fluctuations in young myopic adults.
… oscillating target. The accommodative phase lag was increased following 30 minute adaptation to myopic defocus using +2.00 D lens. However, intense prolonged (30 minute) nearwork was found to have no effect on accommodative gain or phase lag. A number of recommendations for further work …
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Adaptive optics, aberration dynamics and accomodation control. An investigation of the properties of ocular aberrations, and their role in accomodation control.
… and aberration-dependent results. The gain and phase lag of the AR to a sinusoidally moving target were unaffected by aberration correction. The predictable nature of the target had been suggested as the reason for its failure to produce any significant effect on the AR gain and phase lag.
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Semi-active damping of heavy vehicles.
… vehicle model. The prototype damper displays a phase lag of approximately 20ms between the demanded and achieved damping force. The semi-active suspension is found to be most effective in reducing the body accelerations relative to an optimum non-linear passive suspension. A theoretical …
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Hydrogen Permeation Through Nickel And Nickel Alloys: Surface Reactions And Trapping
The frequency variations of attenuation and phase lag of the modulated gas flow through thin metal foils have characteristic features whether permeation is diffusion controlled, is influenced by surface reactions or affected by internal trapping.<br></br><br></br>Analysis of data obtained for …
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Turbulent Boundary Layer over a Piezoelectrically Excited Traveling Wave Surface
… Analysis of the boundary layer at positions phase-locked to the wave oscillation suggests that the traveling waves induce a phase-lag effect in the flow. This phase-lag produces a stretching of the viscous sublayer and may contribute to the skin friction reduction. The effects of standing …
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Momentum, mass, heat, and vorticity balances from oceanic measurements of current and temperature
… occurs in nonlinear processes, is found in a phase lag such that estimates of horizontal advection lead local changes of temperature. In the context of the baroclinic instability model this phase lag is consistent with the growth of perturbation wave energy by conversion of potential energy …
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Advanced Instrumentation and Measurements Techniques for Near Surface Flows
… effect. The fluctuating component of the phase- averaged turbulent boundary layer profiles is described using the exact solution to laminar Stokes flow. A phase lag similar to that in laminar flow is observed with an additional constant phase layer in the buffer region. The phase lag is …
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The classification of slurries and other suspensions using ultrasonic techniques
… size, the particles move with the wave with some phase lag which gives rise to a loss component. At high frequencies, where the wavelength can be made comparable to, and ultimately less than the particle diameter, there is still some movement but most of the energy is lost to the wave by …
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An analysis of profit cycles in the airline industry
… models were developed under the hypothesis that phase lag in the system caused profit oscillations; and two hypotheses, lag in capacity response and lag in cost adjustment were studied. A parametric model was developed by hypothesizing the delay in capacity response caused profit oscillations. …
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Examining the Connection between Guam's Seasonal Rainfall and the El-Nino Southern Oscillation 1950-2023
… El Nino Southern Oscillation (ENSO). Different phases of ENSO may produce deviations from the expected precipitation pattern. Knowledge of this deviation, may assist planners in compensating for changes in water supply. This study will analyze monthly precipitation values from 1950 thru 2023 on …
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Test-Retest Reliability of Coherence Measures of Qeeg During Resting State
… of other qEEG measurements (i.e., coherence and phase lag) as indicators of cognitive function. Coherence has been shown to relate to general intelligence (e.g., Thatcher, et al., 2005), working memory (e.g., Sarnthein et al., 2005) and various neurodevelopmental disorders, such as attention …
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Thermoacoustic Oscillations in Supercritical Fluid Flows
… length of a single fuel tube were separated by a phase lag that was a function of the manifold cross-passage diameter. A lower-frequency mode was also observed, which had a characteristic length based of the summed lengths of a single fuel tube and a single manifold passage. An acoustic simulation …
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Wavelet Analysis and its Application to Modulation Characterization
… are demonstrated by using the magnitude and phase of the wavelet coefficients. The time-varying characteristics of the most unstable modes are determined using the real part of the wavelet coefficients. It is found that mean flow unsteadiness increases the amplitude and phase modulation of …
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X-ray motion analysis of charge particles in a laboratory mill
… mill generated orthogonal to each other, with a phase lag between them. The correction of the phase lag between the biplanar images is a new addition to the usual usage of the system resulting in an effective sampling rate of 100 frames per second, thereby ensuring that the resolution is …
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