Browsing by Subject "magnetic"

Now showing 1 - 5 of 5
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    A Linear Electromagnetic Piston Pump
    (2017-06) Hogan, Paul
    Advancements in mobile hydraulics for human-scale applications have increased demand for a compact hydraulic power supply. Conventional designs couple a rotating electric motor to a hydraulic pump, which increases the package volume and requires several energy conversions. This thesis investigates the use of a free piston as the moving element in a linear motor to eliminate multiple energy conversions and decrease the overall package volume. A coupled model used a quasi-static magnetic equivalent circuit to calculate the motor inductance and the electromagnetic force acting on the piston. The force was an input to a time domain model to evaluate the mechanical and pressure dynamics. The magnetic circuit model was validated with finite element analysis and an experimental prototype linear motor. The coupled model was optimized using a multi-objective genetic algorithm to explore the parameter space and maximize power density and efficiency. An experimental prototype linear pump coupled pistons to an off-the-shelf linear motor to validate the mechanical and pressure dynamics models. The magnetic circuit force calculation agreed within 3% of finite element analysis, and within 8% of experimental data from the unoptimized prototype linear motor. The optimized motor geometry also had good agreement with FEA; at zero piston displacement, the magnetic circuit calculates optimized motor force within 10% of FEA in less than 1/1000 the computational time. This makes it well suited to genetic optimization algorithms. The mechanical model agrees very well with the experimental piston pump position data when tuned for additional unmodeled mechanical friction. Optimized results suggest that an improvement of 400% of the state of the art power density is attainable with as high as 85% net efficiency. This demonstrates that a linear electromagnetic piston pump has potential to serve as a more compact and efficient supply of fluid power for the human scale.
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    Magnetic Attitude Control Development and Simulation for a 3U Cube Satellite
    (2020-01) Kukowski, Timothy
    SOCRATES and IMPRESS are two cubesats designed and built by the University of Minnesota's Small Satellite Team. These satellites have similar build and function by seeking to collect information from photons emitted from celestial objects in space. To do so, a cubesat form factor energy spectrometer, Cesium Iodide, Thalium-doped Incident Energy Spectrometer (CITIES), developed at the University of Minnesota is installed onto a 3U cubesat and operates in low-Earth orbit. For CITIES to collect this data, a reliable attitude determination and control system is important to maintain knowledge of the cubesat's position in orbit and keep the detector pointing towards the required celestial object. Based on a lenient attitude pointing requirement and strict energy budget, magnetic control was chosen as the method of actuation. In this thesis, the justification for and theory behind magnetic attitude control are presented. Operating conditions of the cubesats are briefed. Including a description of the types of controllers, how the controllers lie within the state machine architecture, and the concept of operations leading to the commands provided to the attitude controller. Finally, results from a Matlab simulation are presented using a proportional derivative (PD) controller. Results found indicate that given enough time, the magnetic control system stabilizes the cubesat towards its target.
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    Novel Artificial Urinary Sphincter for Stress Urinary Incontinence Treatment
    (2017-09) Mishra, Avishek
    The American Medical System’s AMS 800TM has been the gold standard for over 40 years with over 150,000 patients treated for Urinary Incontinence and is the leading treatment for male stress urinary incontinence (SUI) following prostate surgery. Type III SUI, or intrinsic sphincter deficiency, is the inability of the urethra to maintain closure pressure sufficient to keep the patient clinically dry at rest and during periods of heightened activity (~120 cmH2O; coughs, sneezes, posture changes, and exercises). The current AMS 800TM is not personalized to a patient’s needs and compromises with an in between pressure- as high (61-70 cmH2O) as it can be without exceeding safety threshold levels. As such many men still leak when they are active. The market is hungry for a device that can adapt to the patient’s level of activity, reducing pressure most of the day to protect the urethra and then briefly increasing the pressure when he is more active. We are developing a novel implantable pump (henceforth called “add-on device”) which will be an add-on to the AMS 800TM and it includes a solenoid coil-cum-plunger and a fluid reservoir within the pump body. The add-on device will be small, light-weight and battery powered, and maintain compatibility with the AMS 800TM device. The device idea is in its proof-of-concept stage. This add-on device can be a possible solution to reducing the risks including urethral atrophy (leading to return of incontinence) and erosion (leading to infection of the implant) resulting from the constant pressure.
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    OFR07-06, Upgrade of Aeromagnetic Databases and Processing Systems at the Minnesota Geological Survey
    (Minnesota Geological Survey, 2007) Chandler, Val W
    During 2005-2007 a program to upgrade the aeromagnetic database for Minnesota was conducted by the Minnesota Geological Survey (MGS). Most of the Minnesota aeromagnetic data were acquired during a 1979-1991 state-wide survey program, and compilation and processing were limited to the computer capabilities of the time. Since that time significant improvements have been made in the development of computers and software that can efficiently handle massive database operations, such as line leveling and gridding. This project was consequently initiated to upgrade the MGS database using up-to-date software and hardware. Access to the data was also to be improved by making all upgraded data available via the web.
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    Search for Slow Magnetic Monopoles with the NOvA Far Detector
    (2020-08) Elashri, Mohamed
    The magnetic monopole is a hypothetical particle with a magnetic charge. It is an important field configuration in many Grand Unified Theories. Dirac in 1931 derived a charge quantization condition, which suggests that the existence of one magnetic monopole in the universe will explain electric charge quantization. Since then, a search of the elusive particle has begun, and yet all came with negative results. The NOvA Far Detector is able to probe some of the parameter space for the search for monopoles. To achieve this, two dedicated triggers, one for fast monopoles and the other for slow monopoles, have been developed to record signals. Results for the first 8 months of high-gain slow monopole data were obtained, and a 90% CL limit was established with no monopole observed. The analysis in this thesis is focused on new data with a higher gain, and we have explored potential improvement in efficiency and improvements in the reconstruction algorithm. We have done this analysis on Monte-Carlo generated simulated data to establish efficiencies and examined a control set of the new data to understand its differences from the old.