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 19 of 19 for “"harmonic frequency"”.
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Optical comb injection for optical demultiplexing and harmonic frequency locking
… could potentially be implemented using optical frequency combs - optical sources which consists of a series of discrete, equally spaced frequency lines. Optical combs can increase the spectral efficiency of these superchannels by allowing the channels to be more densely packed, while …
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Atomic force microscope cantilever with reduced second harmonic frequency during tip-surface contact
… 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 nearly …
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Effects of transmission line compensation and power factor correction on harmonic propagation
… different levels, transmission and utilization. Harmonics injected at these levels can severely degrade the performance and long term reliability of the power system; At the utilization level, a typical industrial power system configuration that requires power factor capacitors and tuned harmonic …
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Multimaterial fiber microelectromechanical systems based on electrostrictive P(VDF-TrFE-CFE)
… deflection is demonstrated up to the second harmonic frequency of the fiber at 158.3Hz, and a modulation depth of 22.5% is reported; for an array of such fibers in PDMS, amplitude modulation is demonstrated at low frequencies with a modulation depth of 25.8%. These results pave the way to the …
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A Method for Measuring Spatially Varying Equivalence Ratios with Application to Thermoacoustics
… fluctuations coinciding with the 1st dominate frequency of the pressure fluctuations and influenced by a 2nd harmonic frequency.
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Numerical Simulation of Plasma-Based Actuator Vortex Control of a Turbulent Cylinder Wake
… of the cylinder and alternately activated at a frequency to produce lock-in behavior. Investigation into the flowfield mechanics reveals that a harmonic frequency of the forced frequency occurs from the creation of sub-vortices from the instantaneous starting and stopping of the moving-wall …
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Design a filter for harmonics caused by non-linear load and resonance coused by power factor correction capacitor
… has become difficult due to the presence of harmonics generated by the non-linear equipment. The resulting capacitive impedance of the PFCC may form a resonant circuit with the source inductive reactance at a certain frequency, which is likely to coincide with one of the harmonic frequency of …
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Microstrip patch array rectenna with harmonic suppression capability for energy harvesting application
… a microstrip patch array rectenna for Radio Frequency (RF) energy harvesting at 2.45 GHz. Energy harvesting is a process where energy is derived from external sources which is captured and converted into power supply. External source being used in this research is RF energy. Rectenna is a …
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A new method for harmonic penetration study in power networks with renewable generation
… it creates power quality issues especially harmonics. In electrical power system, harmonics have a number of undesirable effects on power system equipment as well as on its operation. In order to understand the effects of these harmonics it is first necessary to analyse the penetration of …
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High Fidelity Localization of Energy Autonomous mmIDS for Future Cyber-physical Systems
… technology is the first-ever retro-directive harmonic mmID comprised of dual Rotman lenses and a fully-passive frequency doubler circuit. The mmID is interrogated with a proof-of-concept harmonic frequency modulated continuous wave radar providing accurate long range ranging of the energy …
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Smart grid analysis with particular references to power quality and load forecast
… The proposed algorithm is able to identify all harmonic components including integer, non-integer and sub-harmonics. Comparing with DFT, the proposed algorithm achieves exact estimation of the harmonic frequency. Thirdly, reports on the development of a WT-based dynamic waveform reconstruction …
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Single-sided magnetic nanoparticles imaging scanner for early detection of breast cancer
… signal consists of the fundamental excitation frequency and harmonics. This research utilises the second harmonic response of the MNPs to determine their position and concentration. Analogue Bandpass and Bandstop filters were designed for signal excitation and reception. Resovist and Perimag …
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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 passive …
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Harvesting energy from non-ideal vibrations
… are still based on a single constant vibration frequency. However, most vibration sources do not have a constant frequency nor a single harmonic. Therefore, the inability to deal with non-ideal vibration sources has become a major technological obstacle for vibration energy harvesters to be …
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Lightwave Electronics Based on Nanoantenna Networks
… waveform synthesis and interferometry-free frequency combs. When leveraging rectification, the thesis further illustrates harmonic frequency mixing with bandwidth surpassing that of the input light, enabling the direct detection of PHz frequencies using multi-cycle light from commercial …
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Analysis of Plasma Wave Irregularities Generated during Active Experiments in Near-Earth Space Environment
… emissions offset from the transmitter frequency. These stimulated electromagnetic emissions provide diagnostic information of the ionosphere and thus can be used to investigate fundamental physical principles which govern the earth\'s ionosphere, so that present and future transmission …
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Theoretical Investigation of the Structure and Vibrational Frequencies of Water and Methanol Complexes
… counterpoise corrections. In this investigation harmonic frequencies have been calculated and corrected for the effects of anharmonicity by several methods, two of which are original. The first new method fits a Morse potential function to the energy computed along each normal mode. A second new …
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New-Measurement Techniques to Diagnose Charged Dust and Plasma Layers in the Near-Earth Space Environment Using Ground-Based Ionospheric Heating Facilities
… as utilize experimental observations during High Frequency HF ground-based heating experiments to develop practical techniques for diagnosing these dusty plasma layers.<br />The dependency of the backscattered signal strength (i.e. Polar Mesospheric Summer Echoes PMSEs) after the turn-on and …
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Non-stationary time-dependent ARMA random vibration modeling, analysis & SHM with wind turbine applications
… dynamics. On this sense, the concepts of Harmonic Impulse Response and Harmonic Frequency Response Function (FRF) are adapted to the TARMA case, from which input-output relations in the time-variant system can be derived, and from which the spectral correlation and some types of …