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Full-Text Articles in Engineering

Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise Aug 2016

Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise

Graduate Theses and Dissertations

A steady-state mass diffusion model used with simple measurable and calculable inputs for determining sediment oxygen demand (SOD) is compared to an intact core incubation (ICI) SOD method using samples from three lakes. The mass diffusion model coupled with inputs is known as the measure-calculate method (M-C) and is a potential alternative to existing methods for measuring SOD which are more complex, time-consuming, and costly. The M-C method requires inputs for volumetric sediment oxygen uptake (Ṅsed), sediment density and porosity, and water properties. Ṅsed was determined by suspending sediment in oxygen-saturated water with a DO probe and determining the steady …


Development Of A Reactor Physics Analysis Procedure For The Plank-Based And Liquid Salt-Cooled Advanced High Temperature Reactor, Cole Andrew Gentry May 2016

Development Of A Reactor Physics Analysis Procedure For The Plank-Based And Liquid Salt-Cooled Advanced High Temperature Reactor, Cole Andrew Gentry

Doctoral Dissertations

Presented in this dissertation is the investigation and development of an adapted lattice physics-to-core simulator two-step procedure based on the SERPENT 2 and NESTLE neutronics codes for the rapid analysis of the Advanced High Temperature Reactor (AHTR). AHTR specific characteristics, such as its longer neutron diffusion length and double heterogeneity of TRISO fuel particles, were taken into consideration when adapting the traditional Light Water Reactor (LWR) lattice to nodal diffusion procedure to AHTR applications. The coarse energy group structure was re-optimized from the traditional LWR 2-group structure to an alternative 4-group structures to address the AHTR specific flux spectrum and …


Tunable Controlled Release Of Molecular Species From Halloysite Nanotubes, Divya Narayan Elumalai Apr 2016

Tunable Controlled Release Of Molecular Species From Halloysite Nanotubes, Divya Narayan Elumalai

Doctoral Dissertations

Encouraged by potential applications in rust coatings, self-healing composites, selective delivery of drugs, and catalysis, the transport of molecular species through Halloysite nanotubes (HNTs), specifically the storage and controlled release of these molecules, has attracted strong interest in recent years. HNTs are a naturally occurring biocompatible nanomaterial that are abundantly and readily available. They are alumosilicate based tubular clay nanotubes with an inner lumen of 15 nm and a length of 600-900 nm. The size of the inner lumen of HNTs may be adjusted by etching. The lumen can be loaded with functional agents like antioxidants, anticorrosion agents, flame-retardant agents, …


Perforated Hollow Core Waveguides For Alkali Vapor-Cells And Slow Light Devices, Matthieu C. Giraud Carrier Feb 2016

Perforated Hollow Core Waveguides For Alkali Vapor-Cells And Slow Light Devices, Matthieu C. Giraud Carrier

Theses and Dissertations

The focus of this work is the integration of alkali vapor atomic vapor cells into common silicon wafer microfabrication processes. Such integrated platforms enable the study of quantum coherence effects such as electromagnetically induced transparency, which can in turn be used to demonstrate slow light. Slow and stopped light devices have applications in the optical communications and quantum computing fields. This project uses hollow core anti-resonant reflecting optical waveguides (ARROWs) to build such slow light devices. An explanation of light-matter interactions and the physics of slow light is first provided, as well as a detailed overview of the fabrication process. …


Understanding Electrical Conduction In Lithium Ion Batteries Through Multi-Scale Modeling, Jie Pan Jan 2016

Understanding Electrical Conduction In Lithium Ion Batteries Through Multi-Scale Modeling, Jie Pan

Theses and Dissertations--Chemical and Materials Engineering

Silicon (Si) has been considered as a promising negative electrode material for lithium ion batteries (LIBs) because of its high theoretical capacity, low discharge voltage, and low cost. However, the utilization of Si electrode has been hampered by problems such as slow ionic transport, large stress/strain generation, and unstable solid electrolyte interphase (SEI). These problems severely influence the performance and cycle life of Si electrodes. In general, ionic conduction determines the rate performance of the electrode, while electron leakage through the SEI causes electrolyte decomposition and, thus, causes capacity loss. The goal of this thesis research is to design Si …


Diffusion-Mediated Deposition Of Proteins, Ruiqian Zhan Jan 2016

Diffusion-Mediated Deposition Of Proteins, Ruiqian Zhan

Theses and Dissertations--Mechanical Engineering

Gradients of proteins play a prominent role in many biological processes, from development of multicellular organisms to chemical signaling in the immune system. Deposition of surface gradients is a way to permanently modifying a surface’s properties, resulting in the creation of novel materials which have widespread applications in biologically relevant fields, such as directed cell growth, production of biocompatible implantable materials, and creation of functional biosensors. These types of surfaces can also be used as an ex vivo tool to help understand many biological processes by mimicking the environment in gradient-related phenomena in a controllable way. However, despite the large …