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 26 for “"cryocooler"”.
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Stirling-magnetic cryocooler
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.
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Multi-axis analog adaptive feedforward cancellation of cryocooler vibration
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994.
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A new configuration for a liquid helium temperature cryocooler
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1987
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Modelling of a floating piston expander employed in a 10 K cryocooler
A single stage of a 3-stage Collins-type cryocooler designed to provide I W of cooling at 10 K was constructed and tested. A single stage of the cryocooler consists of a compressor, a counter-flow heat exchanger, and an expander to expand the working fluid. The work of the expanding cold gas is …
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Development of a floating piston expander control algorithm for a Collins-type cryocooler
The multi-stage Collins-type cryocooler uses a floating piston design for the working fluid expansion in each stage. The piston floats between a cold volume, where the working fluid is expanded, and a warm volume. The piston's motion is controlled by opening and closing valves connecting several …
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Analysis and mitigation of key losses in a multi-stage 25-100 K cryocooler
A need exists for small, robust, and efficient cryocoolers operating in the 25-100 K range; however, while technological advances have enabled the development of such machines, a greater understanding of the losses affecting their performance is needed to make informed design tradeoffs. This thesis …
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Development of a cold end and high-efficiency valves for a one-watt 10 Kelvin cryocooler
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.
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Remote cooling using cold electromagnetic values to drive an external flow loop on a G-M cryocooler
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.
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Drawn Polymer Fiber Recuperative Heat Exchangers
Polymer microchannel heat exchangers for use in cryocooler applications have been developed. These heat exchangers are manufactured using a thermal drawing process where a bulk polymer preform is heated and stretched. The process results in channels with a characteristic dimension of 50-100 µm and …
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Critical temperatures of superconducting solders
… ideal. This experiment uses a bucket Dewar and a cryocooler to attempt to cool the solders to 4.2K and determine at which temperature they become superconducting. The setup, however, was not capable of measuring any of the four tested solders' critical temperature. Reasons for this may include …
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Development Of Titanium Nitride/molybdenum Disulphide Composite Tribological Coatings For Cryocoolers
… A Two Stage Reverse Turbo Brayton Cycle (RTBC) CryoCooler is being developed at University of Central Florida. The cryocooler will be used for storage and transport of hydrogen in spaceport and space vehicle application. One part in development of the cryocooler is to reduce the friction and …
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Cryogenic optical refrigeration
… possibilities toward an all solid-state optical cryocooler is within reach.
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Coupling light to superconductive photon counters
… another is for packaging the detector inside a cryocooler. In addition, I have designed and fabricated SNSPDs suitable for the coupling with single-mode fiber, based on my theoretical calculation of the system detection-efficiency. Some important parameters to characterize the detectors such as …
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Superconducting rotor with self-contained thermal management system
… required by aircraft propulsors. Closed-loop cryocoolers with integrated compressors are new options for cryogenic refrigeration because of their independence from liquid transfer. Nevertheless, they deliver only a fraction of the cooling power liquid cryogen does. Therefore, a rotor structure …
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Superconducting RF front-end filters for cell phone base stations
… no longer a disadvantage, through an increase of cryocooler mean time between failure(MTBF) to more than 500,000 hours, and through a recently overturned patent on fail-safe operation in case of cooler failure. Comparable businesses have typical quarterly losses on the order of 10s of millions of …
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A "permanent" high-temperature superconducting magnet operated in thermal communication with a mass of solid nitrogen
… heat capacitors is performed with a detachable cryocooler. The SN2/HTS system offers both improved stability and improved portabilit over an LHe/LTS system design.
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New Optimal High Efficiency Dsp-based Digital Controller Design For Super High-speed Permanent Magnet Synchronous Motor
… The PMSMs are a key component for the miniaturic cryocooler that is currently under development at the University of Central Florida with support from NASA Kennedy Space Center and the Florida Solar Energy Center. Advanced motor design methods, control strategies, and rapid progress in …
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Development of 1GHz Clocked Entangled LEDs for Fibre Networks
… of the ELED inside a compact closed-cycle cryocooler module is demonstrated.
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Two-dimensional quench propagation model for a three-dimensional "high-temperature" superconducting coil
… stainless steel cryostat and cooled by a Daikin cryocooler. The NZP model is based on the two-dimensional transient heat diffusion equation. Quenches arc simulated by a numerical code using the finite-difference method. Agreement between voltage traces obtained in the test magnet during …
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Efficient superconducting-nanowire single-photon detectors and their applications in quantum optics
… with a large-area detector in a closed-cycle cryocooler has been built, demonstrating 24% system detection efficiency with a darkcount rate of -1000 counts/sec. As a result, the SNSPD system becomes a convenient tool with a single-mode fiber as the input channel and an SMA cable as the output …
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