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 2809 for “"Permanent"”.
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Permanent surgical implant alloys.
Massachusetts Institute of Technology. Dept. of Metallurgy and Materials Science. Thesis. 1973. Ph.D.
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Interactions between polyhedral permanent magnets
… energy generation, and electric motor vehicles, permanent magnets are seeing more widespread use than ever before. They permeate our world, enabling sound generation through loudspeakers, mass data storage in the server farms keeping us online, and even the vibration motors in our pockets …
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Kant's Argument for Permanent Substance
… Kant had good reason to claim that there must be permanent phenomenal substances. He needs to account for the possibility of representing reality that we are not now experiencing. He argues that only if substance is permanent can we represent the past. Permanent substance is, therefore, a …
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The temporary and the permanent
… and distinguishing between temporary and permanent areas.
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Permanent Coexistence for Omnivory Models
… of increasing complexity. We use the notion of permanent coexistence, or permanence, to study the long-term survival of three interacting species governed by a mixture of competition and predation. We show the permanence of our models under certain parameter restrictions and include the …
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Overseeding Clovers into Permanent Pastures
Benefits of establishing legumes into permanent pastures have been well studied. Successful establishment of legumes in pastures can be challenging, however, and more information is needed about different seeding methods and variables that affect legume establishment. A pasture and a small plot …
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Sexual Dimorphism in Permanent Human Dentition
Sexual dimorphism refers to differences between males and females of the same species. A general pattern of sexual dimorphism is displayed in humans. Across mammalian populations, males generally have a larger body than females. Many studies have shown that, as body mass increases, tooth volume …
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Design optimization of permanent magnet actuators.
This study describes the design optimization of permanent actuators, of both rotary and linear topologies. Parameter scanning, constrained single and multi-criterion optimization techniques are developed, with due emphasis on the efficient determination of optimal designs. The modelling of devices …
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Radiation Damage in Permanent Magnet Lenses
… Alamos National Lab and elsewhere depend upon permanent magnet quadrupoles in their magnetic optics. Radiation exposure during radiography experiments is known to damage these lenses and degrade image quality. This effect is studied under controlled conditions, leading to the conclusion that …
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Magnetisation reversal in permanent magnet materials
This thesis presents an investigation of the reversal of magnetisation in sintered anisotropic Nd-Fe-B, isotropic melt-spun Nd-Fe-B powder, and in Sm-(Co,Cu,Fe,Zr) 2:17 anisotropic powder. Magnetisation measurements have been performed using vibrating sample magnetometers, a permeameter, and an …
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Torque estimation in permanent magnet synchronous machines
El uso de máquinas síncronas de imanes permanentes ha aumentado notablemente en aplicaciones industriales y de tracción eléctrica durante las últimas décadas, debido a su mejor comportamiento sobre otros tipos de motores eléctricos en aspectos clave como son la densidad de potencia, densidad de …
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New Sensorless Permanent Magnet Synchronous Motor Drive
In permanent magnet synchronous motor (PMSM) drives, magnetic-saliency-based techniques have been widely used to detect rotor position and speed, especially during the starting and low-speed operations. Among these techniques, pulsating high-frequency signal injection (PHFSI) stands out as a …
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A study of permanent-magnet torque motors
Thesis (M.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1953.
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Modeling and optimization of permanent magnetic motors
… the prediction and optimization of radial-flux permanent magnet motor torque and efficiency. It also facilitates the design optimization of electromagnetically-powered rotorcraft by characterizing optimal motor performance over a wide range of motor mass. The solution of the Poisson Equation, …
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Super High-speed Miniaturized Permanent Magnet Synchronous Motor
This dissertation is concerned with the design of permanent magnet synchronous motors (PMSM) to operate at super-high speed with high efficiency. The designed and fabricated PMSM was successfully tested to run upto 210,000 rpm The designed PMSM has 2000 W shaft output power at 200,000 rpm and at …
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Fault Tolerant Sensorless Permanent Magnet Synchronous Motor Drives
High cost and complexity of fault tolerant motor drives has relegated them to mission critical, no-compromise applications. Heeding to this target application, past research efforts have been mainly focused on developing highly redundant, multiphase fault-tolerant solutions able to assure a very …
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The Dynamic Stability of Permanent-Magnet Step Motors
Made available in DSpace on 2014-12-12T20:55:01Z (GMT). No. of bitstreams: 1 8004255.pdf: 8658158 bytes, checksum: c2bf13aec68772fdbbf6e865d3778542 (MD5) Previous issue date: 1979
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Rotordynamic assessment for a permanent magnet synchronous motor
High speed and high rotor tip-speed, in particular, combined with high magnetic and electrical loading, are key enablers for obtaining high specific power in electric machines. The rotor described in this thesis pushes the tip speed to about 80% of the speed of sound. An outer rotor design with a …
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Begging the question : permanent income and social mobility
Includes abstract. Includes bibliographical references (p. 35-37).
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