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 8 of 8 for “"logarithmic spiral"”.
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EVALUATION OF THE LOGARITHMIC SPIRAL SEARCH PATTERN FOR ANTISUBMARINE WARFARE
… a recently lost target submarine using the logarithmic spiral search pattern. The study was done by developing a stochastic, time-step simulation to data farm quantitative information. The measures of effectiveness are time to regain contact, distance away from contact on regain, and overall …
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Investigation of a more optimum trajectory than the logarithmic spiral in solar sailing
A logarithmic spiral trajectory is not the optimum trajectory for a solar sailing space vehicle. Investigation of the governing equations showed that the performance of the solar sail depends on one parameter "a". This parameter "a", defined simply as the ratio of radial to tangential forces, was …
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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
… to the geometric structure of late type (spiral) galaxies, specifically 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 …
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A Study of Techniques to Solve the Disparate Mesh Size Problem With an Application to Sinuous Antennas
… sinuous antenna is geometrically related to the logarithmic spiral antenna, but its mode of operation is fundamentally different. The logarithmic spiral antenna is a traveling wave antenna, while the sinuous antenna is more like a resonant antenna.
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Solar Sailing Adaptive Control Using Integral Concurrent Learning for Solar Flux Estimation
… interplanetary transfer orbit following a logarithmic spiral reference trajectory. The proposed formulation demonstrates the benefit of estimating the solar flux using integral concurrent learning. Results are compared to trajectories with no estimation to illustrate the need to account for …
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Investigation of Trajectory and Control Designs for a Solar Sail to the Moon
… quadratic regulator controller to follow a logarithmic spiral reference trajectory and ensure the stability of the solution. As a result, a robust thrust vector control solution to minimize error from the reference trajectory was found and a solution method to assign the control gain matrix …
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Spiral 2D array designs for volumetric imaging
… sampled at the Nyquist rate) based on geometric spiral structures, with the aim to reduce the number of array elements, and therefore transmit-receive channels required to meet a given acoustic specification. The aperiodic structure of these array designs is shown to minimise the height of …
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Scale-model investigation of brittle tunnel failure using a true-triaxial device
… stress conditions and improves the theoretical logarithmic spiral plastic slip lines that rely solely on friction angle. In conclusion, this research improves the understanding of brittle failure mechanisms in tunneling, contributing to safer and more reliable tunnel designs in brittle rock …