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 44 for “"axis of rotation"”.
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Effective development of cylindrical finite-difference time-domain for electromagnetics applications
Computationally, the size of the domain is important in terms of the memory and time to complete the run and collect the results. Thus, a conventional perfectly matched layer (PML) can be used to truncate computational regions in numerical methods. This will reduce the memory size and the time to …
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Ground-based ISAR imaging of cooperative and non-cooperative sea vessels with 3-D rotational motion
Inverse Synthetic Aperture Radar (ISAR) images of sea vessels are a rich source of information for radar cross section (RCS) measurement and ship classification. However, ISAR imaging of sea vessels is a challenging task because the 3-D rotational motion of such vessels often gives rise to …
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Effects of oversized particles on the dynamic properties of sand specimens evaluated by resonant column testing
… that many times intact specimens with a number of oversized particles are dynamically tested in the laboratory and the impact of the particles on the dynamic properties is unknown. The effects of oversized particles represented by gravel particles on the shear modulus (G) and material damping …
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Axisymmetric Rayleigh-Benard convection
This thesis considers axisymmetric Rayleigh-Benard convection in an infinite horizontal layer of fluid heated from below major emphasis is placed on a study of the effect of rotation of the layer, where both the stationary and overstable cases are analysed. In Chapter 2, a numerical solution of the …
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Analysis of Lumbar Spine Kinematics during Trunk Flexion and Extension Motions
The effectiveness of exercise has been increasingly studied as exercise has been popular for the improvement of physical performance and rehabilitation of lumbar spine. A variety of exercises have been used to reduce back pain or spinal degeneration. However, there are no studies to determine …
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The temperature distribution on a spherical shell in the presence of a primary radiative source and a reflecting and radiating infinite plane
… with a constant angular velocity about an axis of rotation oriented perpendicular to an infinite plane located at some unspecified distance from the shell, is exposed to a distant source of parallel radiation. The plane is assumed to radiate diffusely as well as reflect heat energy. …
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Skylight Polarization Patterns as Cues for Honey Bee Orientation; Physical Measurements and Behavioral Experiments
<p>This thesis reports the results of behavioral, theoretical, and physical studies of the use of solar and skylight cues by animals for orientation. The principal features of skylight radiation which may be important for orientation are reviewed, together with previous investigations of honey bee …
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Nonsmooth Dynamics in Two Interacting, Impacting Pendula
… thesis reviews the experimental investigation of a non-smooth dynamical system consisting of two pendula; a large pendulum attached to a frame with an impact wall, and a small pendulum, which shares its axis of rotation with the large pendulum and can impact against the large pendulum. The …
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A Biologically Plausible Neuron Model of Mental Rotation
… thesis presents a biologically plausible account of mental rotation. To this end, there is evidence that mental rotation is a spatial imagery task that can invoke a variety of strategies, depending on the nature of the stimuli. This thesis uses simple but unfamiliar stimuli, which engenders a …
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A study of vibrations in rotating laminated composite plates accounting for shear deformation and rotary inertia
… accounts for geometric non-linearity in the form of von Karman strains. The plate is permitted to have arbitrary orientation and offset from the axis of rotation. A finite element model is developed to obtain a solution to the problem. The model is validated by comparing the results for free …
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Design and testing of a pan-tilt mechanism for severe environments
… electronic warfare devices installed, which are often supported and trained by two-axis gimbals. In current shipboard solutions the payloads are often placed on a platform above the gimbal drive train, which results in high moment loads on drive components during a wave impact. As the payloads …
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Mixed convection and heat management in the Mars gravity biosatellite
… orbit satellite spinning about its longitudinal axis. The satellite's payload thermal control system will reject heat through the base of the payload module and provide air circulation vital to maintaining a habitable environment for the mice. The centripetal acceleration due to rotation creates …
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Artificial gravity : evaluation of adaptation to head movements during short-radius centrifugation using subjective measures
… was performed to determine the ability of humans to adapt, and retain adaptation to out-of-plane head movements made during short-radius centrifugation. The hypothesis for the experiment was as follows: Repeated exposure to a series of yaw head movements made during short-radius …
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Development and Application of a BioRobotic Simulation of Stance Phase Gait to Study Foot and Ankle Kinematics
<p>Ankle instantaneous axis of rotation (IAR) measurements represent a more complete parameter for characterizing joint motion. However, few studies have implemented this measurement to study normal, injured, or pathological foot-ankle biomechanics. Additionally, while load is suggested to play a …
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Quantifying ballet technique through turn kinematics for injury assessment
… and prevent injury. Variation in knee angle of a dancer's supporting leg during pirouettes of 1-5 rotations was measured using a goniometer for 12 professional and pre-professional ballet dancers. Plié angle saw no significant difference for different numbers of rotations, but the effect of …
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Vertical axis wind turbine with continuous blade angle adjustment
The author presents a concept for a vertical axis wind turbine that utilizes each blade's entire rotational cycle for power generation. Each blade has its own vertical axis of rotation and is constrained to rotate at the rate of one half of a revolution per full revolution of the rotor. For a rotor …
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Helical magnetorotational instability in MHD Taylor-Couette flow
Magnetorotational instability (MRI) is one of the most important and most common instabilities in astrophysics. Today it is widely accepted that it serves as a major source of turbulent viscosity in accretion disks, the most energy efficient objects in the universe. The importance of the MRI for …
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Analyis Of Airborne Microwave Polarimetric Radiometer Measurements In The Presence Of Dynamic Platform Attitude Errors
… 7]. This technique is based upon the anisotropy of the polarized ocean blackbody emissions at microwave frequencies relative to the azimuth angle between the microwave radiometer antenna "look" direction and the direction of the wind. Because of the weak wind direction signature, it is important …
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Maneuver and control of flexible spacecraft
This dissertation is concerned with the problem of slewing large flexible structures in space and simultaneously suppressing any vibrations. The equations of motion for a three-dimensional spacecraft undergoing large rigid-body maneuvers are derived. The elastic motions are assumed to remain in the …
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Development Of Design Equations For A Square-tube Subbase Supporting A Shaft-mounted Speed Reducer
… as conveyor systems for transporting ore out of mine shafts. A subbase joins the reducer with an electric motor, and serves to limit the misalignment between the motor shaft and the reducer input shaft. The entire assembly is supported at two points: the axis of rotation of the reducer output …
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