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 20 of 161 for “"ripples"”.
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An experimental study of wind ripples
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1981.
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Experimental study of current ripples using medium silt
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982.
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A numerical study of vortex dynamics over rigid ripples
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1988.
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Generation of sand ripples and sand bars by surface waves
Part I Generation of Sand Ripples by Surface Waves In Chapter 1, we study the sand ripple instability under partially standing surface waves in constant water depth. For gently sloped ripples, the approximate flow field is· worked out. By invoking an empirical formula of sediment transport rate, an …
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Velocity moment analysis on oscillatory flow above self-formed vortex ripples
… of oscillatory flow above self-formed vortex ripples. Using the data collected by Admiraal et al. (2006), phase-averaged and time-averaged mean velocities, root-mean-square speeds, turbulent kinetic energy, Reynolds shear stress, and higher order velocity moments including skewness factors, …
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Seafloor ripples created by waves from Hurricane Ivan on the west Florida shelf
… studies have shown that the presence of sand ripples on the seabed improves sonar detection of buried mines at sub-critical angles. Sidescan sonar data of ripples on the west Florida shelf were collected as part of ONR's Ripples Departmental Research Initiative (DRI) September 26-29th and …
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Lotus Pond, Bicultural Ripples: The Psychological Orientations of Korean-Canadian Practitioners of Buddhism
This dissertation examines whether Buddhist beliefs and practices serve to reinforce and/or promote a Korean and/or Canadian cultural prism for next-generation Korean Buddhist practitioners in Toronto, Canada. I define Korean and Canadian cultural prisms based on the cross-cultural psychological …
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Gravity waves and ripples near the mesopause above Davis Station, Antarctica. 1999-2013
… of short-period gravity waves (GWs) and ripples near the mesopause (~87 km altitude). The main findings are as follows: 1. Two distinct distributions of horizontal wavelength were observed both obeying the relation
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Seafloor ripples created by waves from hurricane Ivan on the west Florida shelf
… studies have shown that the presence of sand ripples on the seabed improves sonar detection of buried mines at sub-critical angles. Sidescan sonar data of ripples off on the west Florida shelf were collected as part of ONR's Ripples Departmental Research Initiative (DRI) September 26-29th and …
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Field oriented control of permanent magnet synchronous motor with third-harmonic injection pulse width modulation to reduce quadrotors’ speed ripples
… performance of dynamic response and fewer speed ripples. Field Oriented Control (FOC) is one type of vector controls to control a PMSM in a quadrotor. FOC of PMSM and Pulse Width Modulation (PWM) are introduced. The simulation results of FOC of PMSM with third-harmonic injection PWM and …
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Granular retrosplenial cortex layer 2/3 generates high frequency oscillation events coupled with hippocampal sharp wave-ripples and Str. LM high gamma
… processes take the form of theta and sharp wave ripples (SPW-Rs) for encoding and consolidation, respectively. As an animal runs through an environment, neurons become active at specific locations in the environment (place cells) increasing their firing rate, functionally representing these …
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When ripples becomes waves : exploring the role of policy in the creation and coordination of citizen participation in Minnesota‟s water governance landscape.
The term "environmental governance" is used to describe the increasingly collaborative nature of environmental natural resource policy creation and implementation that incorporates a diversity of third party actors ranging from government agencies to the profit sector, nonprofit sector, and civic …
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Bed Morphology and Sediment Transport Under Oscillatory Flow
… Regarding the planform geometry of the ripples, the results showed that narrow facilities restrict the three-dimensional development of bedforms. For the case of the long water excursion experiments, the ripple size was found to initially decrease as the maximum orbital velocity was …
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Using remote sensing to track complex sinuous ripple migration on a barchan dune in Herschel Crater, Mars
Dunes on Mars are known to migrate, in particular ripples have also been found to migrate. This is known to have occurred in eastern, western and southern Herschel Crater, but it was not known if this was true for Central Herschel Crater. Central Herschel Crater is of particular interest as the …
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Studies of ion beam nanopatterning on silicon and polymer thin film
… on surfaces, including nanodots, nanoscale ripples, and nanoscale pits or holes. Research in this thesis is mainly focused on the behavior of ripple patterns on silicon surfaces as a function of the ion incidence angle. A preliminary study of ion beam nanopatterning of polymer thin films is …
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High-performance torque control of switched reluctance motor
Motor torque ripples may cause speed ripples at low speed operation. Switched Reluctance Motor (SRM) produces excessive torque ripples due to discrete excitation of phase windings and its non-linear magnetization characteristics. A new polynomial model in phase current and rotor position is …
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Flow, sediment transport and bedforms under combined flows
… and divided into no motion (NM), 2D symmetric ripples (SR), 3D symmetric ripples (SR), 3D symmetric dunes (SR), 3D asymmetric ripples (AR), 3D quasi-asymmetric ripples (QAR), 3D asymmetric dunes (AD), 3D current ripples (CR), 3D current dunes (CD) and upper-stage plane bed (USPB). Each of these …
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Memory processing of novel experiences in the hippocampus
… field potential recordings, called ‘sharp wave-ripples’. I show that during sharp wave-ripples, which are believed to reflect a retrieval mode of the hippocampal network, the place cells that were active in a novel environment fired more often than other place cells that were active in a …
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The Influence of Aging and Parkinson’s Disease on Neural Oscillations Associated with Memory Consolidation
… Specifically, high-frequency oscillations, or ripples, in the hippocampal formation are required for the conversion of short-term to long-term memory. These ripples couple to two slower oscillations found in the cortex, delta waves and spindles. The author describes here his contributions to …
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