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 792 for “"Hysteresis"”.
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Inertial Hysteresis Couplings
This thesis presents the Inertial Hysteresis Coupling (IHC), a new family of variable-slip mechanical couplings/clutches aimed at achieving order-of-magnitude (∼10x) improvements in torque density (torque capacity / coupling diameter) over existing magnetic and fluid options. IHCs leverage combined …
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Hysteresis of nitrocellulos films
Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1936
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Hysteresis in textile bending.
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1968.
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Two Methods for Modeling Scalar Hysteresis and their use in Controlling Actuators with Hysteresis
… of a positioning system that exhibits scalar hysteresis requires a control strategy that incorporates compensation for the hysteresis. One approach is to develop a compensator based on an inverse hysteresis operator. This method uses an open loop control in which the inverse operation adjusts …
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Adsorption Hysteresis in Porous Media
The phenomenon of adsorption hysteresis in porous media is studied from a microscopic point of view via computer simulations based on statistical mechanics principles.
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Contact angle hysteresis and the energy principle
Experimental evidence suggests that contact angle hysteresis is related, in some cases, to surface roughness or heterogeneity on a microscopic scale. This work investigates the effect of periodic roughness or heterogeneity on quasi-static motion of a liquid/vapor/solid contact line. We determine …
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Continuum Mechanics of Duhem’s Approach to Hysteresis
Although the Duhem model of hysteresis was introduced in the late nineteenth century, it has not received particular attention for nearly a century. Only in the late twentieth century did researchers begin to cite and attribute this model to Pierre Duhem, employing it as a “black-box model” in …
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Analysis of hunting in Synchronous Hysteresis Motor
The Synchronous Hysteresis Motor has an inherent instability when it is used to drive a gyroscope wheel. The motor ideally should spin at a constant angular velocity, but it instead sporadically oscillates about synchronous speed. This phenomenon is known as 'hunting'. This problem produces current …
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Creep, elastic hysteresis and damping in bakelite
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1938.
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Parameter Identification for the Preisach Model of Hysteresis
Hysteresis, defined as a rate independent memory effect, is a phenomenon that occurs in many physical systems. The effect is sometimes desired, sometimes a nuisance, sometimes catastrophic, but in every case we must understand hysteresis if we are to better understand the system itself. While the …
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Hysteresis modeling of wood joints and structural systems
… modeled properly. This thesis presents a general hysteresis model for wood joints and structural systems, based on a modification of the Bouc-Wen-Baber-Noori (BWBN) model. The hysteretic constitutive law, based on the endochronic theory of plasticity and characterized by a single mathematical …
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A Hysteresis Model for Reinforced Concrete Space Frame Structures
A hysteresis model to simulate the behavior of reinforced concrete columns subjected to biaxial bending and varying axial load is proposed. The model, identified as the U-model, is based on cross-sectional properties. The U-model combines the Otani's modification of the Clough model and the Ziegler …
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Evaluation of gas spring hysteresis losses in Stirling cryocoolers
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1990.
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Hysteresis and memory effects in nanocrystal embedded MOS capacitors
… quasi-static capacitance characteristics reveal hysteresis which is evidence for the memory effect. A hysteresis of 2 V is demonstrated which is large enough to enable the use of nanocrystal embedded devices as memory devices. Measurement results suggest that the tunneling in the accumulation …
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A high-speed hysteresis motor spindle for machining applications
… critical research areas. The focus is on a hysteresis motor topology using a solid, inherently-balanced D2 steel shaft. An analytical model of the motor is devised in order to make performance predictions and optimization, and an experimental apparatus is constructed in order to verify the …
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Magnetically suspended reaction sphere with one-axis hysteresis drive
… suspended reaction sphere with one-axis hysteresis drive (1D-MSRS). The goal of this project is two fold: (a) exploring the design for a reaction sphere in 3D for spacecraft's attitude control, and (b) studying the performance of the hysteresis motor in reaction wheel applications. The …
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Sinusoidal Analysis of Hysteresis Effects in Nonlinear Feedback Control Systems
Made available in DSpace on 2014-12-04T21:03:19Z (GMT). No. of bitstreams: 1 6101616.pdf: 3194447 bytes, checksum: c94460df6b6e5d7cd7c5f3c3ec50f14e (MD5) Previous issue date: 1961
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Modified Maxwell Model for hysteresis compensation of piezoelectric stack actuators
This thesis presents new observations of the hysteresis behavior of piezoelectric stack actuators and proposes an Input-Range Dependent Maxwell Model for more accurate hysteresis compensation. Experimental studies show that the assumptions of the classical Maxwell model do not fully hold: the …
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Exploiting the concept of hysteresis in ankle dysfunction and ankle strengthening
… and muscles leads to ankle dysfunction. The hysteresis concept was employed to determine if there is any ankle dysfunction. A recently developed device, the Ankle Torsion Monitor (AnTm) was employed to evaluate the viscoelasticity and stiffness of the ankle joint. The greater the hysteresis …
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