Engineering Commons^™

Design, Manufacturing And Control Of An Advanced High-Precision Robotic System For Microsurgery, Arezoo Ebrahimi

Electronic Theses and Dissertations

Microsurgeries like ophthalmic surgery confront many challenges like limited workspace and hand motion, steady hand movements, manipulating delicate thin tissues, and holding the instrument in place for a long time. New developments in robotically-assisted surgery can highly benefits this field and facilitate those complicated surgeries. Robotic eye surgery can save time, reduce surgical complications and inspire more delicate surgical procedures that cannot be done currently by surgeon’s hands. In this thesis work, the requirements for ophthalmic surgeries were studied and based on that a robotic system with 6 DOF is proposed and designed. This robotic

system is capable of handling …

Behavior Of Buried Composite Arch Bridges, Harold J. Walton

Electronic Theses and Dissertations

This dissertation presents experimental results and numerical analysis for short-span buried composite arch bridges whose main structural members are concrete-filled fiber reinforced polymer (FRP) tube arches (CFFTs). This investigation focuses on soil- structure interaction of the bridge system to expand understanding beyond isolated arch performance. Soil plays several roles: weight on the structure, restraining arch movement, and dissipating surficial truck loads.

Investigation focused on experimental and numerical analysis of subscale bridge systems. Four bridge systems were constructed with two different span-to-rise ratios (5:1 and 2.67:1) and two different materials (linear-elastic steel and CFFT). Tested systems were half-scaled from commercial bridge …

Correlation Of Engineering Parameters Of The Presumpscot Formation To The Seismic Cone Penetration Test (Scptu), Mathew Hardison

Electronic Theses and Dissertations

The seismic cone penetration test with pore pressure measurement (SCPTu) is a geotechnical investigation technique which involves pushing a sensitized cone into the subsurface at a constant rate while continuously measuring tip resistance, sleeve friction, and pore pressure resulting from soil shearing. Additionally, shear wave velocity measurements can be collected at discrete intervals throughout the test. Empirical and theoretical correlations have been developed between these measurements and soil engineering properties such as preconsoldiation pressure and undrained shear strength. Soil classification, location of silt/sand seams, seismic design parameters, and liquefaction potential can also be obtained from SCPTu results.

The objective of …

The Role Of Al And Fe In Controlling Internal P Loading, Lake Auburn, Me, Heather Doolittle

Electronic Theses and Dissertations

Lake Auburn, Maine, U.S.A. is a historically oligotrophic lake serving as the primary drinking water source to a population of 40,000. In 2011 and 2012 the local water district observed decreasing water quality, evidenced by increasing epilimnetic total phosphorus (P) concentrations, increasing lake turbidity and the appearance of cyanobacteria. These conditions are especially concerning due to Lake Auburn’s exemption from filtration by the EPA. The decline in water quality has been linked to widespread hypolimnetic summer anoxia, causing internal P loading from the lake sediment. This study evaluated the chemical P speciation in hypolimnetic sediment from Lake Auburn following the …

Accelerating Scientific Computing Models Using Gpu Processing, Raymond F. Flagg Iii

Electronic Theses and Dissertations

GPGPUs offer significant computational power for programmers to leverage. This computational power is especially useful when utilized for accelerating scientific models. This thesis analyzes the utilization of GPGPU programming to accelerate scientific computing models.

First the construction of hardware for visualization and computation of scientific models is discussed. Several factors in the construction of the machines focus on the performance impacts related to scientific modeling.

Image processing is an embarrassingly parallel problem well suited for GPGPU acceleration. An image processing library was developed to show the processes of recognizing embarrassingly parallel problems and serves as an excellent example of converting …

Detailed Low-Cost Energy And Power Monitoring Of Computing Systems, Chad M. Paradis

Electronic Theses and Dissertations

Power and energy are increasingly important metrics in modern computing systems. Large supercomputers utilize millions of cores and can consume as much power as a small town; monitoring and reducing power consumption is an important task. At the other extreme, power usage of embedded and mobile devices is also critically important. Battery life is a key concern in such devices; having detailed power measurement allows optimizing these devices for power as well. Current systems are not set up to allow easy power measurement. There has been much work in this area, but obtaining power readings is often expensive, intrusive, and …

Microengineering The Neural Tube, Christopher Demers

Electronic Theses and Dissertations

Early embryonic development is a complex and highly regulated orchestra of instructive cues that collectively guide naïve stem cells towards progressively more specialized fates. In the neural tube, the precursor structure to the brain and spinal cord, these signals emanate from ‘organizing centers’ surrounding the neural tube. These organizing centers send out soluble cues or morphogens that diffuse tens to hundreds of microns to recipient cells residing in the neural tube. Re-creating this dynamic landscape of cues in vitro is impossible using standard cell culture tools and techniques. However, microfluidics is perfectly suited to fill this gap, allowing precise control …

Challenges Of Implementing Automatic Dependent Surveillance Broadcast In The Nextgen Air Traffic Management System, Carl J. Giannatto Jr.

Electronic Theses and Dissertations

The Federal Aviation Administration is in the process of replacing the current Air Traffic Management (ATM) system with a new system known as NextGen. Automatic Dependent Surveillance-Broadcast (ADS-B) is the aircraft surveillance protocol currently being introduced as a part of the NextGen system deployment. The evolution of ADS-B spans more than two decades, with development focused primarily on increasing the capacity of the Air Traffic Control (ATC) system and reducing operational costs. Security of the ADS-B communications network has not been a high priority, and the inherent lack of security measures in the ADS-B protocol has come under increasing scrutiny …