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 16 of 16 for “"Mechanical Resonance"”.
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Understanding and predicting transient material behaviors associated with mechanical resonance in cementitious composites
… Recently, nonlinear transient dynamic mechanical resonance behaviors, also known as “slow dynamic” behaviors, have been observed in damaged cementitious composite materials, yet the physical mechanisms underlying these behaviors are not understood. These phenomena hold potential to …
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A critical investigation into the properties of metallised film capacitors for high quality sound reproduction
… identical whilst exhibiting differinglevels of mechanical resonance within the audio frequency band. Results obtainedfrom subjective listening tests have shown this to have a measurable effect on audiodelivery.The listening test methodology employed in this study evolved from initial ABX …
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Resonance Compensation of Large AC Drivetrains with Significant Time Lag
… used in the rolling mill industry to deal with mechanical resonance tend to fall apart with large values of time lag. We investigate a modified LQR/LQE approach using a torque sensor as the feedback element. The result is a low order SISO filter that suppresses the effects of the torque ripple …
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Optimized pulsing of high-intensity focused ultrasound for enhanced therapeutic window
… when high duty cycle pHIFU is pulsed at the mechanical resonance of the medium. Up to 50% increase in temperature was measured in lab-prepared tissue mimicking phantoms. The therapeutic gain achieved by pHIFU over cwHIFU is attractive as no modifications on the currently used applicators are …
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Suspended microchannel resonators for biomolecular detection
… channel is detected by measuring the change in mechanical resonance frequency of the channel. In contrast to resonant mass sensors submersed in water, the sensitivity and frequency resolution of the suspended microchannel resonator is not degraded by the presence of the fluid. Our device differs …
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High performance amplifier topologies implemented with a micro-machined vibrating capacitor
… but electrically isolated fully differential mechanical transconductor input stage that is fabricated using SOI-MEMS technology. The MEMS sensor will act as a vibrating capacitor input stage. It will provide galvanic isolation and up-modulation of the input signal as it vibrates. The galvanic …
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Piezoelectric Micro Power Generator (PMPG) : a MEMS-based energy scavenger
… d₃₃ mode of the piezoelectric. When excited into mechanical resonance, the PMPG acts as a current generator whose charge can be stored by an electrical charge storage system. A single PMPG device delivered more than 1 [micro]W of DC power at 2.36 V DC to an electrical load from an ambient, …
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Design and comparison of two brushless DC drives for an electric propulsion system of solar-power unmanned aerial vehicles
… A 3D stator model was built to analyse the mechanical resonance frequencies and possible excitation by the electromagnetic radial force leading to vibration and noise for the proposed and conventional rotor structure. Analytical calculation of natural mode frequencies has also been conducted …
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The effects of changing head position and posture on head tremor in individuals with essential tremor involving the head
… interplay of the central driver and the mechanical resonance driving the amplitude changes. Decreasing stability of posture increases head tremor, likely due to the associated increase in postural sway and stress on the postural control system. Vision appears to exacerbate head tremor …
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Modelling and Analysis of Close Contact Ultrasonic Power Transfer Systems with Metal Barriers
… is Ultrasonic Power Transfer (UPT), using mechanical particle vibrations and electromechanical conversion to enable the electrical power transfer. Power transfer through metal barriers has already been validated in the extant academic literature, but there are many behaviours that have not …
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Magnetoelectric laminated composites and devices
… and decreases the required optimum DC bias. The resonance frequency of Terfenol-D/PZT laminates can be continuously tuned by magnetic field over a wide range. This large tunability is due to the large magnetostriction of Terfenol-D. It results in a dramatic increase in the bandwidth over which …
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Charakterisierung galvanisch abgeschiedener Nickel- und Nickel-Wolfram-Schichten für mikrotechnische Anwendungen
… circuits and combination with micro mechanical components. Fabrication processes of micro system technology supplement microelectronic components with mechanical microstructures. Sensor and actuator concepts can thus be realized and supporting structures for assembling and mounting …
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Materials selection for microsystems actuators
… in the design philosophy of Micro-Electro- Mechanical Systems (MEMS) from process centric to performance centric. This presents an opportunity to improve the performance of MEMS devices by materials selection beyond the commonly preferred candidates compatible with the …
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Acoustic biosensing using functionalised microbubbles
… acoustic wave can set a microbubble into mechanical resonance. The resonant frequency is strongly dependent on the shell properties (thickness, elasticity, viscosity, $\textit{etc.}$), and it is affected by a layer of material attaching to its surface. Existing analytical models in the …
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Vibration as a method for muscular stimulation
… Whole body vibration training (WBVT) aims to mechanically activate muscles by eliciting neuromuscular activity (muscle reflexes) via the use of vibrations delivered to the whole body. The most mentioned mechanism to explain the neuromuscular outcomes of vibration is the elicited neuromuscular …
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Magneto-mechanical systems for ultra-low frequency data transmission: Dynamics, losses, and driving mechanisms
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2026-12-01