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 90 for “"Pitch angle"”.
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A probe to measure stagnation pressure, static pressure, yaw and pitch angle
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.
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Orbital effects on pitch angle diffusion of injected fast-ion beams in tokamaks
The effects of ion orbits on pitch angle scattering of fast ion beam injection are investigated here for the magnetic equilibrium of the ITER tokamak. Two methods are used to calculate distributions in the presence of orbits, one applying boundary conditions a posteriori and one a priori. In both …
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The Mass-Pitch Angle Relation for Three High Redshift Active Galaxies Selected from the GOODS Field
… showing a relationship between the spiral arm pitch angle and that central mass, here we push that relationship out to distances of redshift one. With three galaxies at this distance we find that they also hold to the same relationship of tighter spiral arms corresponding to more massive …
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Mean flow and turbulence measurements in the wake of a slender propeller-driven body including effects of pitch angle
… produced by a stern-propeller-driven body at pitch angles of 0º and -2° is presented. The effect of an appendage such as a submarine sail to an axisymmetric body is also considered. Mean flow velocities, static pressure, flow angularity, and turbulence quantities are presented at three …
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The Disk Structure of Late Type Galaxies: Determining the Black Hole Mass Function of Low Surface Brightness Galaxies Through Logarithmic Spiral Arm Pitch Angle Measurement
… on the relation between the logarithmic spiral pitch angle of the galactic spiral arms with other properties of the galaxy, such as central Supermassive Black Hole (SMBH) mass. Our work continues a study of the Black Hole Mass Function (BHMF) in local galaxies by recording the pitch angles of …
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Dark Matter Halo Concentration and the Evolution of Spiral Structure in N-Body, Barred Spiral Galaxies
… by the evidence of relationships between pitch angle (the tightness of spiral arm structure in the disk), P, and various indicators of central mass concentration, as well as the theoretical relationship between halo mass concentration and the density of visible matter in the central part …
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Overvoltage Prevention in Low Voltage Rural Distribution Network with High Penetration of Wind Energy
… systems, this can be achieved by adjusting the pitch angle of the wind turbine. The objective of this thesis was to develop an active power curtailment strategy for small wind turbines to prevent overvoltage by controlling the pitch angle of the turbine blades. An equation was developed relating …
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Design of a controllable pitch underwater thruster system
… of the thrust actuators. Standard fixed-pitch propellers have been shown to have very poor dynamic characteristics, particularly at low thrust levels The dynamic response of a fixed-pitch propeller is dependent upon highly non-linear transients encountered while the shaft speed approaches …
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The crystal structure of cholesterol helical ribbons
… but remarkably, almost all the helices have a pitch angle of 11⁰ or 54⁰. The consistent pitch angle of the ribbons may be due to an underlying crystal structure. In order to determine the crystal structure, I undertook x-ray scattering studies of individual helical ribbons taken from two …
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Feedback linearization and adaptive control of a nonlinear aeroelastic system
… and simulation results show that control of pitch angle and plunge displacement can be accomplished; Then, adaptive output feedback control law is examined. For the synthesis of the controller, it is assumed that only pitch angle and plunge displacement are measured. A canonical state …
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RF wave observations in beam-plasma discharge
… the threshold current IC taking into account the pitch angle injection dependence is given. Ambient plasma density inferred from wave measurements under various beam conditions are reported. It is observed that the maximum frequency of the excited RF band behaves differently than the frequency of …
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The use of foil generated vorticity as a hover actuator system for undersea vehicles
… regime of foil motion amplitude, frequency, pitch angle offset, pitch angle amplitude and phase angle for two types of motion. Using the time-averaged thrust coefficient, I find that the lower frequencies provide the highest thrust coefficient of 3.1 at G0=600, hdc= 1.5, and f=0.4Hz for the …
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The Design and Construction of a 20" x 20" Mach 2.0 Blowdown Wind Tunnel to Characterize the Lift and Drag of Irregularly Shaped Fragments
… tested at Mach 2 flow, over an effective 360° pitch sweep, with wind tunnel runs performed every 10 degrees. Based on the measured force data for both fragments, the lift appeared to follow a sinusoidal curve, with minimum values at 0, 90, and 180° balance pitch angle, and maximum values …
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Interstellar helium pickup ion flux variations observed with SOHO/CELIAS
… fluctuations can scatter pickup ions, in both pitch angle and energy. Comparison with WIND/MFI magnetic field measurements show that the pitch angle scattering rate is correlated with the wave-power. A hemispheric model for the pickup ion distribution is used to determine pitch angle diffusion …
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Force control in flapping foils using in-line motion and passive pitch
… shown that by actuating the heave, surge, and pitch motions of a foil and iteratively optimizing the results, the lift and thrust forces on the foil can be precisely and independently controlled. In this thesis, the same experiment is modified to include solely passive pitch to determine if …
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Enabling wind turbine generators to participate in power grid frequency regulation for enhanced stability
… adjustment can be realized by both converter and pitch angle control in addition to inertial response of the wind turbine. This helps in maintaining instantaneous power balance as well as in longer term frequency regulation.</p> <p>In the second paper, Inertia controller, pitch angle controller …
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Minimum Energy Control Strategy for an Uninhabited Airship with a Moving Gondola
… investigated with the goal of achieving a large pitch angle and of minimizing the total energy consumption required to goal position. The airship in this study is equipped with different actuation tools such as a moving gondola and a vectoring thrust, which can be used for various flight modes. …
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A fully numerical lifting line method for the design of heavily loaded marine propellers with rake and skew
… which the wake is aligned with the hydrodynamic pitch angle. The second approach, in which the wake is aligned with the local velocities, utilizes Kutta's Law to create a zero-lift wake surface. A thorough comparison of the influence of the effect of tip vortex roll-up is done. A lifting surface …
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Ion Cyclotron Resonance Heating Induced Transport in Stellarators and Other Asymmetric Toroids
… coefficients of drag, velocity diffusion, and pitch angle scattering (PAS). Ion drift orbit equations of motion are set in a magnetic flux coordinate system which separate fast motion along the field lines from slow motion across the lines.
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Behavior of Wind Turbine Towers and Blades Under Tornado Wind Fields
… actions on the tower and blades, and the optimal pitch angle that will minimize the effects of that tornado. Design wind profiles for tornadoes are developed in this study taking into account several factors. The proposed wind profiles are presented as wind speeds in the rotor plane and …
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