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 61 for “"oscillation frequency"”.
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Experimental Sensitivity Analysis and Control of Thermoacoustic Systems in the Linear Regime
… of some combustion systems. Thermoacoustic oscillations arise due to feedback between acoustic waves and unsteady heat release rate when the fluctuating heat release rate is sufficiently in phase with the unsteady pressure. The primary aim of designers is to design linearly stable …
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Oscillating shock impingement on low-angle gas injection into a supersonic flow
… were designed to allow tuning of the shock frequency to the estimated frequency, about 100 - 150 kHz, of the largest eddies in the approach boundary layer. Visualization using nanoshadowgraph photography showed large turbulent structures in all cases. In addition, there were clear changes in …
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Investigation of batch and continuous crystallisation processes using non-invasive Raman and acoustic emission spectrometries
… (by integrating the AE intensity over specific frequency ranges) and changes in particle size (by ratioing the intensities at high and low frequency regions). A design of experiments approach evaluated the effects of solution concentration, oscillation frequency and amplitude, and final …
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High-Speed Silicon-Germanium BiCMOS and Indium Phosphide DHBT Receiver ICs for Optical and Wireless Communications
… InP processes. The InP AIVCOs demonstrate 20-GHz oscillation frequency and over 50% tuning range. The measured do power for a single InP active inductor is only 15 mW from a 4-V power supply.
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Enhanced transport through confined channels by stationary and fluctuating potentials
… across the channel is obtained by adjusting the oscillation frequency. At the optimal oscillation frequency, the translocation rate of particles through the channel is a hundred times higher with respect to free diffusion across the channel. Our findings reveal the effect of time dependent …
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A mm-scale aeroelastic oscillation-based anemometer
… aeroelastic and vortex-forced flutter modes, its oscillation frequency can be confined to scale smoothly with fluid velocity. This principle has been used to produce a low-cost, mm-scale anemometer that measures air flow to ±(5% + 0.5m/s) from 1-25m/s. This paper describes the prototype and the …
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Observation of B⁰s - B⁻⁰s oscillations using partially reconstructed hadronic Bs decays
… in the world's first observation of B⁰s - B⁻⁰s oscillations. The analysis is a core member of a suite of closely related studies whose combined time-dependent measurement of the B⁰s - B⁻⁰s oscillation frequency Am, is of historic significance. Using a data sample of 1 fb-1 of pp collisions at V …
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A measurement of B⁰ anti-B⁰ oscillations using fully-reconstructed hadronic B decays at BaBar
Flavor oscillations of neutral B mesons have been studied with e+e- annihilation data collected at center of mass energies near the [gamma](4S) at the PEP-II asymmetric collider with the BABAR detector. One B⁰ is fully reconstructed in a hadronic decay to a flavor eigenstate. The flavor of the …
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Numerical Study of Nutrient Mixing in Trabecular Bone in Microgravity, Disuse and Normogravity
… bone loss. This thesis investigates how oscillation frequency and trabecular bone density jointly control nutrient mixing and wall shear stress within trabecular cavities.</p> <p>A computational fluid dynamics (CFD) framework is developed in STAR-CCM+ using a soft-cap oscillation model …
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The oscillogenic instrument
… system such that the system oscillates. The oscillation frequency can be made a function of concentration, reaction kinetics, transport phenomena, and other physical properties. The idea was reduced to practice with an electronic system coupled to an electrochemical system, and gave a …
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A mathematical study of the role of calcium in the regulation of saliva secretion
… across the cytosol. We construct a model of Ca2+ oscillations in parotid acinar cells that requires paired oscillations of IP₃. This ODE model reproduces a number of experimentally observed phenomena. The model is later spatially extended. An inhomogeneous distribution of Ca²⁺ channels is shown to …
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On the passive oscillations of a splitter plate in stratified turbulence
… Ld=c 2[2, 8]. Results show that the plate oscillations is dominated by two distinct modes. One of them corresponds to the mean flow-induced oscillation frequency, fp, whereas the other is synchronized with the cylinder vortex shedding frequency, fv. The trends of these two frequencies is …
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Flow-Mediated Interaction Between a Vibrating and an Elastically-Mounted Cylinder
… of parameters. The active cylinder’s oscillation frequency f1/ fn ranges from 0.05 to 3.2; the amplitude of the active cylinder A1/D varies from 0.025 to 1.432; the mass ratio of the passive cylinder m∗ takes the value of 1.5, 1.7, 2.0, 2.2 or 2.5; the structural damping factor of the …
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Experimental Investigation of Transonic Shock Oscillations on NACA 0018 at Incidence
… region of the shock. This code calculated the frequency spectrum at regular points along the range of shock motion and plotted the spatial distribution of frequency spectra across all the points. This identified the location of the high-amplitude frequencies, which indicated the precise range …
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Aerodynamics of a chined forebody oscillating in pitch
… attack without sideslip. The effects of reduced frequency as well as free-stream Reynolds number were investigated by running a range of tunnel velocity/model oscillation frequency combinations. Reynolds numbers, based on the 3-inch base diameter of the forebody, of 1.4 x 10$\sp5$ to 2.8 x …
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Analysis of B [sigma] flavor oscillations at CDF
The search for and the study of flavor oscillations in the neutral B,B, meson system is an experimentally challenging endeavor. This constitutes a flagship analysis of the Tevatron proton-antiproton collider physics program. In this dissertation we develop such an analysis of the time-dependent B, …
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Frequency and Damping Characteristics of Generators in Power Systems
… is essential for maintaining the power system oscillation frequency within a small and acceptable interval around its nominal frequency. Hence, it is necessary to study and control the frequency for stable operation of a power system by knowing the characteristics within a power system. One …
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Airfoil-vortex interaction and the wake of an oscillating airfoil
… airfoil about its quarter-chord at a reduced frequency of k = 2.05 and an amplitude of ±10° angle of attack. The target airfoil, a NACA 63₂A015, was immersed in the wake, two chord lengths downstream of the vortex generators trailing edge. Phase-averaged velocity measurements of the flow …
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Analytical and experimental investigation of a 1/5 scale rail vehicle simulator
… The linear model predicts the truck's natural Frequency versus speed within 5% of the experimental values. lt also predicts the damping ratio decrease that occurs with increasing truck speed. The nonlinear model simulates the lateral instability known as hunting. The nonlinear model and the …
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Modelling of liquid droplet dynamics in a high DC magnetic field
… These external forces are found to modify the oscillation frequency and damping rates, which need to be quantified in order for the measurement technique to be used. The dynamics of the droplet are three-dimensional but previous numerical work has largely focused on axisymmetric cases. This …
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