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 26 for “"Mode Frequency"”.
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Atomic force microscope cantilever with reduced second harmonic frequency during tip-surface contact
… cantilever design for which the second flexural mode frequency can be tailored relative to the first mode frequency, for operation in contact with a substrate. A freely-resonating paddle internal to the cantilever reduces the stiffness of the second flexural mode relative to the first while …
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Effect of ball impact location and temperature on softball bat handle vibration
… was performed. The bats resonate in two main frequency ranges associated with the first bending mode and a hoop mode. The bending mode frequency was consistent across all impact locations, but did vary slightly between bat types. The hoop mode frequency varied depending on location. Hitting a …
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Multidisciplinary design of thermally radiating structures using a level set based topology optimization approach
… method. Both von Mises stress and first mode frequency constraints are implemented since they are commonly found in aerospace design problems where severe structural loads can lead to catastrophic failure. The final contribution is testing several data mining techniques to identify …
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A tuneable quantum gas for matter wave interferometry and soliton experiments
… geometry.We study the fundamental breathing mode frequency of a single matter-wave soliton by measuring its oscillation frequency as a function of the atom number and confinement strength and we observe signatures of the creation of secondorder solitons.;Aside from introducing some general …
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MATLAB implementation of an operational modal analysis technique for vibration-based structural health monitoring
… to the dynamic responses from two finite element models of simply-supported beams and their modal frequencies and shapes were extracted. The first three modal frequencies were obtained with less than 6 percent error from the actual values and the fundamental mode shape values obtained contained …
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Computation Of The Response Of Thin Piezoelectric Films
… The FEA process used is discussed in terms of mode frequency, harmonic, and spectrum analysis. The structural analysis data of the shell substrate is imported into Matlab for further processing using numerical differentiation and integration. The processed data is then used to calculate the …
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Characterization of cellulose esters via GPC/FT-IR
… chloride the carbonyl asymmetric stretching mode frequency observed at ≈1753 cm⁻¹ was found to be dependent upon the extent of acetyl substitution. This work developed a method for the quantitative determination of the degree of nitration of cellulose nitrates as a function of the polymer …
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Enhanced Modulation Dynamic Performance of Optically-Injected Widely-Tunable Semiconductor Lasers
… is devoted to a comprehensive theoretical and modelling study of dynamic modulation characteristics of semiconductor wide-wavelength tunable laser diodes (TLDs). The two major goals were to investigate how modulation properties of a TLD depend on the wavelength tuning, and how the modulation …
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Intentional nonlinearity in the small scale with applications to atomic force microscopy (AFM) and mass sensing
… of a new cantilever design during multi-frequency tapping mode AFM is studied. The system consists of a base cantilever with an inner paddle which, under harmonic excitation, vibrates like a system of linearly coupled oscillators engaging simultaneously a lower, in-phase and a higher, …
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Hydrogen Enrichment Effects on Thermoacoustics of Turbulent Partially Premixed Flames
… and thermoacoustic instability in Gas Turbine Model Combustors (GTMC). A bimodal thermoacoustic instability where two different modes are excited are investigated using Large Eddy Simulations (LES) for a partially premixed swirl stabilised methane-air flame in a GTMC. Simulations are also …
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Nonlinear dynamics of a matter-wave soliton in driven potentials
… energy transfer to the soliton occurs in two frequency regimes: on resonance with the trapping frequency and on resonance with the internal mode frequency of the soliton. The former regime is well described by modelling the soliton effectively as a rigid particle, and in this regime energy …
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Nonlinear dynamics of a matter-wave soliton in driven potentials
… energy transfer to the soliton occurs in two frequency regimes: on resonance with the trapping frequency and on resonance with the internal mode frequency of the soliton. The former regime is well described by modelling the soliton effectively as a rigid particle, and in this regime energy …
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Theoretical studies of the VASIMR plasma propulsion concept
… the excitation of radially localized helicon modes by an external antenna. The radial density gradient in a plasma forms a potential well for the modes, with the resulting mode frequency being significantly lower than that for a uniform plasma. This explains the high efficiency of the source …
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Quantum Mechanically Derived Biomolecular Force Fields
… small molecules and subsequently transferred to model large proteins. Here, we look to challenge this assumption and create a new class of QUantum mechanical BEspoke (QUBE) biomolecular force fields. QUBE is based around the use of atoms-in-molecule electron density partitioning to derive the …
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Terahertz oscillation and stimulated emission from planar microcavities
… of the light wavelength, where the photonic modes are con- fined and the number of states is limited. In the smallest microcavities, i.e. micrometer sized optical resonators, the propagation of only one mode is permitted that is simultaneously amplified internally. This particularly strong …
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Adjoint-based control of turbulent jet noise
… using the dynamic Smagorinsky sub-grid-scale model. For the time horizon over which the control is applied, the most intense noise events are almost completely removed. At a jet exhaust angle of 30 degree, the far-field peak spectral noise reduction is 5.6 dB at the jet column mode frequency …
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A microscopic theory of tunneling
… impurity vibrating at a (Einstein) local mode frequency, All electron-impurity (l~cal-mode-phonon) interactions appear in this formalism as self-energy corrections to the extended-basis electronic wave functions, The position of the impurity relative to the junction-region determines both …
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Pivot-Point-Independent Mode-Hop-Free Tunable Laser with a Large Tuning Range and Narrow Linewidth
… which is pivot-point-independent with a large mode-hop-free tuning range and fast tuning speed. The research focuses on the laser cavity design that achieves mode-hop-free tuning. <br/><br/>Among the diverse categories of tunable lasers, external cavity tunable lasers demonstrate superior …
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Quantifying microbubble streaming and its applications
… and (ii) results in much wider surface-mode frequency resonance peaks than is nominally predicted by potential flow theory. The oscillatory dynamics then feed into a calculation of the secondary flow, which rigorously accounts for boundary layers over the bubble and the wall. We show …
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Evolution of the distribution of high energy nuclei and induced collective modes in plasmas
… effects and interactions with collective modes in the plasma will be considered. Part of this research will focus on the distribution of high energy nuclei undergoing motion in unperturbed orbits. This work utilizes appropriate symmetry properties and conservation laws, including the …
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