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 16 of 16 for “"Ultra low frequency"”.
-
Ultra-low frequency wireless transmitter design using resonant oscillating permanent magnets
Electromagnetic signals in the ultra-low frequency (ULF) range of 3-3000 Hz has low signal attenuation and high penetration depth, making them ideal for underwater and underground wireless communication systems. However, the large wavelength of ULF signals (10^2-10^5 km) necessitates conventional …
-
Ultra-Low Frequency Waves at Middle Latitudes During Substorms: Observations and Modeling
… presents the results of investigation of the Ultra-Low Frequency (ULF) waves at middle latitudes during substorms. The dissertation consists of two major parts, observations and simulations. The research in this dissertation proposes that the main role in the generation of ULF waves at middle …
-
Magneto-mechanical systems for ultra-low frequency data transmission: Dynamics, losses, and driving mechanisms
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2026-12-01
-
Occurrence Statistics and Driving Mechanisms of Ionospheric Ultra-Low Frequency Waves Observed by SuperDARN Radars
Ultra-low frequency (ULF; 1 mHz - 1 Hz) waves are known to play an important role in the transfer of energy from the solar wind to Earth's magnetosphere and ionosphere. The Super Dual Auroral Radar Network (SuperDARN) is an international network consisting of 35 low-power high frequency (HF: 3-30 …
-
Digital Signal Processing and Machine Learning Applied to Power Line Communications
… of signal demodulation and bit classification in ultra-low-frequency, baseband PLC systems operating in the electrical distribution grid.
-
Dynamic mechanical analysis of magnetic tapes at ultra-low frequencies
… the correlated effects of temperature and frequency on the viscoelastic behavior of magnetic tapes, using a custom, ultra-low frequency, dynamic mechanical analyzer. The long-term mechanical and thermal properties of magnetic tapes can be simulated using high temperature and low frequency …
-
Dynamic viscoelastic properties of advanced magnetic tapes
… storage magnetic tape materials, using a custom ultra-low frequency dynamic mechanical analyzer (DMA). Through the correlated effects of frequency and temperature, the long term mechanical properties of the magnetic tape can be simulated and used for predictive analysis of long term storage …
-
Global investigation of large earthquakes using long-period seismic data
… (GCMT), for large magnitude (Mw ≥ 7.5) shallow thrust earthquakes. We show that SCARDEC source parameters explain normal mode data as well as GCMT, and that SCARDEC dip angles explain body wave data similarly or slightly better than GCMT solutions. SCARDEC dip angles also agree well with …
-
Effect of Interplanetary Shock Impact Angle on the Occurrence Rate and Properties of Pc5 Waves Observed by High-Latitude Ground Magnetometers
The effects of interplanetary shock impact angles have the potential to have far reaching consequences. By their nature, interplanetary shocks are a direct consequence of a variety of solar events including both Coronal Mass Ejections (CMEs) and Co-rotating Interaction Regions (CIRs). They have the …
-
Development of ground-based search -coil magnetometer systems in the polar regions and studies of ULF Pc 1--2 wave propagation in the ionospheric waveguide
… observations of geomagnetic pulsations in the ultra low frequency (ULF) range (a few mHz to a few Hz). The design, fabrication, and test/calibration have been performed to detect very weak geomagnetic pulsations with approximately a few pT resolution over the frequency range 0 --- 2.5 Hz and …
-
Thick Conducting Polymer Coatings for Safe Electric Field Delivery to the Spinal Cord
… electrodes in sustained direct current and ultra-low frequency stimulation of the injured spinal cord. Finite element modelling in anatomically realistic spinal cord geometries demonstrates that electrode area, spacing, and placement are the principal determinants of uniform and safe …
-
Ionospheric Disturbances: Midlatitude Pi2 Magnetospheric ULF Pulsations and Medium Scale Traveling Ionospheric Disturbances
… systems, especially those which utilize radio frequency energy. By studying ionospheric disturbances, it is possible to gain a deeper understanding of not only the ionosphere itself, but also the natural and technological systems it is coupled to. This dissertation research utilizes high …
-
New Way of Generating Electromagnetic Waves Using Permanent Magnet
… data rate, which leads to the use of higher frequency bands and wider bandwidths in modern communication technology research and innovations. However, increasing frequency in many technology areas cannot necessarily be beneficial because of physical constraints. For example, communication …
-
Ultra-low and wide bandwidth vibrational energy harvesting using a statically balanced compliant mechanism
… by piezoelectric effect in particular. The frequency gap between the majority of energy harvesting devices (with narrow bandwidth in the high frequency range) and the accessible vibrational sources (at 1-10 Hz levels) is observed and is still to be filled. In this thesis, a structural …
-
Theoretical and Experimental Studies of Manipulation of Elastic Waves in Helix Metamaterials
Helix metamaterials; Wide low-frequency bandgap; Controllable design; Laser vibration measurement; Strong vibration attenuation; Carrera Unified Formulation Abstract Elastic metamaterials exhibit mechanical properties unattainable in natural materials and demonstrate vast potential in vibration and …
-
A statistical study of plasmawaves and energetic particles in the outer magnetosphere
… loss cone. EMIC waves correspond to the highest frequency waves in the ultra-low frequency (ULF) spectral regime, and field line resonances at the lower frequency may serve as diagnostics for the plasma distribution in the magnetosphere. This dissertation investigates (1) a rapid, efficient way …