Engineering Commons^™

Solvent Engineering Of Molybdenum Disulfide Electrocatalyst For Hydrogen Evolution., Robert Carl Spalding

Electronic Theses and Dissertations

Energy is at an exponentially growing demand, and to keep up with these demands new technologies for renewable energy have received increased attention. Hydrogen plays a vital role in water electrolysis and fuel cells, as the hydrogen evolution reaction (HER) is the main step water splitting process. Most of the current electrocatalysts for HER are dominated by platinum and other precious metals due to their low over-potential and small Tafel slope, however, they are extremely costly. For this reason, cost-effective non-precious metal catalysts must be developed. Transition metal dichalcogenides, such as molybdenum disulfide (MoS2), are abundant and have recently shown …

Optics Of Two-Dimensional Materials Used As Substrates For Nanoparticle-Based Devices, Reagan Newman

Chancellor’s Honors Program Projects

No abstract provided.

Photocatalytic Carbon Dioxide Conversion To Fuel For Earth And Mars, Anne J. Meier

USF Tampa Graduate Theses and Dissertations

As far as we know, we only have one planet to live on, with a delicate atmospheric system providing us safety and life. Global CO2 emissions continue to plague the environment of Earth, primarily due to the processing of fossil fuels, deforestation, and industrialization. There are several avenues of pursuing CO2 reutilization, each having their own benefits and limitations. Direct and indirect thermochemical approaches of CO2 conversion boast of efficient CO2 conversion rates but have limitations associated with the use of renewable hydrogen and high temperatures of operation. The work in this dissertation investigates low temperature photocatalytic CO2 conversion, a …

Structural Control Of Wind Turbines With Soil Structure Interaction Included, Breiffni Fitzgerald, Biswajit Basu

Articles

The importance of considering soil structure interaction in structural control of wind turbines is investigated in this paper. An Euler–Lagrangian wind turbine mathematical model based on an energy formulation was developed for this purpose which considers the structural dynamics of the system and the interaction between in-plane and out-of-plane blade vibrations. Also, the interaction between the blades and the tower including a tuned mass damper (TMD) is considered. The turbine is subject to turbulent aerodynamic loading simulated using a modification to the classic Blade Element Momentum (BEM) theory with turbulence generated from rotationally sampled spectra. The turbine is also subject …

Cable Connected Active Tuned Mass Dampers For Control Of In-Plane Vibrations Of Wind Turbine Blades, Breiffni Fitzgerald

Breiffni Fitzgerald

In-plane vibrations of wind turbine blades are of concern in modern multi-megawatt wind turbines. Today׳s turbines with capacities of up to 7.5 MW have very large, flexible blades. As blades have grown longer the increasing flexibility has led to vibration problems. Vibration of blades can reduce the power produced by the turbine and decrease the fatigue life of the turbine. In this paper a new active control strategy is designed and implemented to control the in-plane vibration of large wind turbine blades which in general is not aerodynamically damped. A cable connected active tuned mass damper (CCATMD) system is proposed …

Active Tuned Mass Dampers For Control Of In-Plane Vibrations Of Wind Turbine Blades, Breiffni Fitzgerald

Breiffni Fitzgerald

This paper investigates the use of active tuned mass dampers (ATMDs) for the mitigation of in-plane vibrations in rotating wind turbine blades. The rotating wind turbine blades with tower interaction represent time-varying dynamical systems with periodically varying mass, stiffness, and damping matrices. The aim of this paper is to determine whether ATMDs could be used to reduce in-plane blade vibrations in wind turbines with better performance than compared with their passive counterparts. A Euler–Lagrangian wind turbine mathematical model based on energy formulation was developed for this purpose, which considers the structural dynamics of the system and the interaction between in-plane …

Bioengineering Approach To Understanding Tmj Pathobiology, Jonathan Kuo

All Dissertations

The temporomandibular joint (TMJ) is a load-bearing joint consisting of the condyle of the mandibular bone, the fossa eminence of the temporal bone, and a fibrocartilaginous disc held in between the bone surfaces by ligaments. The TMJ disc serves to distribute stress, lubricate movement, and protect the articular surfaces of the joint. Over ten million Americans suffer from TMJ disorders (TMD) that affect the movement and function of the joint, making everyday tasks like talking and eating difficult and painful. A wide variety of treatments and surgeries have been proposed and undertaken with limited success based on the varying degree …

Slides: Oil Shale Water Needs, State Water Planning And The Colorado River Compact, Daniel R. Birch

The Promise and Peril of Oil Shale Development (February 5)

Presenter: Daniel R. Birch, Deputy General Manager & Chief Engineer, Colorado River District

17 slides