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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Modeling the Influence of Vibration on Flow Through Embedded Microchannels

Seamons, Joseph S 06 December 2023 (has links) (PDF)
The influence of vocal fold (VF) vibration on perfused flow through VF vasculature is an area of research that has previously received limited attention. The aim of the research presented in this thesis was to contribute towards an improved understanding of the effects vibration on perfusion through vasculature within the VFs. This was done using a series of computational simulations of geometric changes to, and perfusion through, microchannels embedded in VF models. A computational structural model based on synthetic VF models used in previous experimental studies was first developed. The model and its embedded microchannel were initially studied under static pressure loads applied to the inner surfaces of the channel as well as to the VF inferior and medial surfaces. It was shown that the channel volume decreased linearly and the channel length increased quadratically with increasing pressure on the external VF surfaces. Changes in Poisson's ratio and its influence on the embedded channel's maximum deflection, volume, and length were also studied. Across the range of Poisson's ratios that has been studied for silicone used in synthetic VF models (0.4 to 0.495) there was shown to be limited change in microchannel maximum deflection, channel length, and volume for equivalent pressure loads. The model was then modified to include an external oscillating pressure load on the VF surface that caused the model to vibrate. Two separate studies were conducted to determine how frequency and deflection amplitude affected the predicted perfusion flow rate through the embedded microchannel by accounting for the changes in microchannel geometry during vibration. These studies showed that frequency had little effect on predicted flow rate, while increased deflection amplitude led to greater reductions in predicted flow rate. These reductions in flow rate were attributed to channel lengthening and cross section deformation during vibration, with the latter playing a much larger role. Reductions in flow rate results were found to favorably agree with measured experimental flow rate reductions reported previously. Computational fluid dynamics simulations of water flowing through the inflated embedded microchannel during vibration were also conducted. These simulations were used to explore how changes in vibration length, amplitude, and frequency affected the fluid dynamics in the microchannel whilst minimizing geometric changes to the microchannel. The flow rates from each of the simulation cases were compared to determine which of the vibration parameters contributed the most to flow losses. Vibration length and amplitude were shown to be statistically significant. An investigation was undertaken to further elucidate the mechanisms behind the flow losses induced by vibration. The effects of channel elongation, increased channel curvature, pressure rises, and pressure gradients during vibration were analyzed. Changes in channel elongation and pressure were shown to significantly contribute to flow losses and flow rate reduction. The results from these simulations were compared with the structural simulations which analyzed how changes in microchannel geometry affected flow rate reductions. Changes in the microchannel geometry were shown to contribute much more significantly to reductions in perfusion flow rate compared to changes in vibration parameters (i.e., vibration length, amplitude, and frequency).
152

Compliant Motion Programming for Robust Robotic Surface Finishing

Buckmaster, David J. January 2009 (has links)
No description available.
153

Effect of Compliant Flooring on Postural Stability in an Older Adult Population and in Individuals with Parkinson's Disease

Beach, Renee January 2013 (has links)
No description available.
154

A Variable Stiffness Robotic Arm Design Using Linear Actuated Compliant Parallel Guided Mechanism.

Hu, Ruiqi January 2017 (has links)
No description available.
155

Modern Mechanical Automata

McCrate, Mark P. January 2010 (has links)
No description available.
156

Wind Tunnel Testing of a Variable Camber Compliant Wing with a Unique Dual Load Cell Test Fixture

Zientarski, Lauren Ann January 2015 (has links)
No description available.
157

An Experimental and Numerical Investigation of Closed-loop Impedance Pumping in Compliant, Elastic Tube Millistructures

Rich, Bryan C. 10 June 2016 (has links)
No description available.
158

Design Optimization and Classification of Compliant Mechanisms for Flapping Wing Micro Air Vehicles

Ryan, Mark 31 August 2012 (has links)
No description available.
159

Advancing Manufacturing Quality Control Capabilities Through The Use Of In-Line High-Density Dimensional Data

Wells, Lee Jay 15 January 2014 (has links)
Through recent advancements in high-density dimensional (HDD) measurement technologies, such as 3D laser scanners, data-sets consisting of an almost complete representation of a manufactured part's geometry can now be obtained. While HDD data measurement devices have traditionally been used in reverse engineering application, they are beginning to be applied as in-line measurement devices. Unfortunately, appropriate quality control (QC) techniques have yet to be developed to take full advantage of this new data-rich environment and for the most part rely on extracting discrete key product characteristics (KPCs) for analysis. In order to maximize the potential of HDD measurement technologies requires a new quality paradigm. Specifically, when presented with HDD data, quality should not only be assessed by discrete KPCs but should consider the entire part being produced, anything less results in valuable data being wasted. This dissertation addresses the need for adapting current techniques and developing new approaches for the use of HDD data in manufacturing systems to increase overall quality control (QC) capabilities. Specifically, this research effort focuses on the use of HDD data for 1) Developing a framework for self-correcting compliant assembly systems, 2) Using statistical process control to detect process shifts through part surfaces, and 3) Performing automated part inspection for non-feature based faults. The overarching goal of this research is to identify how HDD data can be used within these three research focus areas to increase QC capabilities while following the principles of the aforementioned new quality paradigm. / Ph. D.
160

Series Elasticity in Linearly Actuated Humanoids

Orekhov, Viktor Leonidovich 21 January 2015 (has links)
Recent advancements in actuator technologies, computation, and control have led to major leaps in capability and have brought humanoids ever closer to being feasible solutions for real-world applications. As the capabilities of humanoids increase, they will be called on to operate in unstructured real world environments. This realization has driven researchers to develop more dynamic, robust, and adaptable robots. Compared to state-of-the-art robots, biological systems demonstrate remarkably better efficiency, agility, adaptability, and robustness. Many recent studies suggest that a core principle behind these advantages is compliance, yet there are very few compliant humanoids that have demonstrated successful walking. The work presented in this dissertation is based on several years of developing novel actuators for two full-scale linearly actuated compliant humanoid robots, SAFFiR and THOR. Both are state-of-the-art robots intended to operate in the extremely challenging real world scenarios of shipboard firefighting and disaster response. The design, modeling, and control of actuators in robotics application is critical because the rest of the robot is often designed around the actuators. This dissertation seeks to address two goals: 1) advancing the design of compliant linear actuators that are well suited for humanoid applications, and 2) developing a better understanding of how to design and model compliant linear actuators for use in humanoids. Beyond just applications for compliant humanoids, this research tackles many of the same design and application challenges as biomechanics research so it has many potential applications in prosthetics, exoskeletons, and rehabilitation devices. / Ph. D.

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