Engineering Commons^™

Molecular-Level Modeling Of Proton Transport In Aqueous Systems And Polymer Electrolyte Membranes: A Reactive Molecular Dynamics Study, Myvizhi Esai Selvan

Doctoral Dissertations

Proton exchange membrane (PEM) fuel cells are an eco-friendly power source that has great potential to reduce our oil dependence for our stationary and transportation applications. In order to make PEM fuel cells an economically viable option, further effort is needed to improve proton conduction under wide operating conditions and reduce the cost of production. Design and synthesis of novel membranes that have superior characteristics require a fundamental molecular-level understanding of the relationship between the polymer chemistry, water content and proton conduction. The performance of a fuel cell is influenced by the electrochemical and molecular/proton transport processes that occur at …

Radiation-Curable Adhesives For Wood Composites, Timothy H. Starr

Masters Theses

Wood composites are widely used in construction applications because of their superior dimensional and structural attributes over raw wood products. However, current wood composite manufacturing practices, which rely on thermal-curing of adhesives, are expensive, energy intensive, time consuming and are prone to manufacturing defects. Use of radiation curable adhesives (RCAs) could potentially answer all of these issues. Specifically, use of electron-beam (e-beam) radiation has been increasing in areas of research and industry where rapid, low-temperature polymerization is required and low energy consumption is desired. For e-beams to be used in wood composites, however, it must be determined whether or not …

An Adaptive Nonparametric Modeling Technique For Expanded Condition Monitoring Of Processes, Matthew John Humberstone

Doctoral Dissertations

New reactor designs and the license extensions of the current reactors has created new condition monitoring challenges. A major challenge is the creation of a data-based model for a reactor that has never been built or operated and has no historical data. This is the motivation behind the creation of a hybrid modeling technique based on first principle models that adapts to include operating reactor data as it becomes available.

An Adaptive Non-Parametric Model (ANPM) was developed for adaptive monitoring of small to medium size reactors (SMR) but would be applicable to all designs. Ideally, an adaptive model should have …

Molecular Simulations Of Adsorption And Diffusion In Metal-Organic Frameworks (Mofs), Ruichang Xiong

Doctoral Dissertations

Metal-organic frameworks (MOFs) are a new class of nanoporous materials that have received great interest since they were first synthesized in the late 1990s. Practical applications of MOFs are continuously being discovered as a better understanding of the properties of materials adsorbed within the nanopores of MOFs emerges. One such potential application is as a component of an explosive-sensing system. Another potential application is for hydrogen storage.

This work is focused on tailoring MOFs to adsorb/desorb the explosive, RDX. Classical grand canonical Monte Carlo (GCMC) and molecular dynamic (MD) simulations have been performed to calculate adsorption isotherms and self-diffusivities of …

Multi-Scale Simulation Of Linear, Short-Chain Polyethylene Liquids Under Flow Conditions, Jun Mo Kim

Doctoral Dissertations

The rheological and structural properties of polymeric liquids cannot be condensed within a single numerical model. They should be described within hierarchical, multi-level numerical models in which each sub-model is responsible for different time and length scales; atomistic, mesoscopic, and continuum. In this study, the rheological and structural properties of linear, short-chain polyethylene liquids were investigated from the classical atomistic level to the mesoscopic and continuum levels of description. At the atomistic level of description, nonequilibrium molecular dynamics (NEMD) simulations of linear, short-chain polyethylene liquids spanning from C16H24 to C128H256 were performed to advance our knowledge of fundamental characteristic of …

Ph Effect On The Arsenic Separation In Waste Water Of Coal Based Power Plant, Ye Hao

Masters Theses

Arsenic (As) poses a significant water quality problem and it is a big challenge for all coal-based power plant industries worldwide. Currently most of the researches on the leaching behavior of arsenic from fly ash are based on the titration experiments. In this study a simulation method is used to study on the pH effect on the arsenic separation of coal-based power plants. Both single point and composition survey simulation of the OLI stream analyzer are used in the study. The simulation results of single point calculation indicates that for the fly ash which has high lime weight percent and …

Dynamics Of Individual Molecules Of Linear Polyethylene Liquids Under Shear: Atomistic Simulation And Comparison With A Free-Draining Bead-Rod Chain, J. M. Kim, B. J. Edwards, David J. Keffer, B. Khomami

Faculty Publications and Other Works -- Chemical and Biomolecular Engineering

Nonequilibrium molecular dynamics (NEMD) simulations of a dense liquid composed of linear polyethylene chains were performed to investigate the chain dynamics under shear. Brownian dynamics (BD) simulations of a freely jointed chain with equivalent contour length were also performed in the case of a dilute solution. This allowed for a close comparison of the chain dynamics of similar molecules for two very different types of liquids. Both simulations exhibited a distribution of the end-to-end vector, |R_ete|, with Gaussian behavior at low Weissenberg number (Wi). At high Wi, the NEMD distribution was bimodal, with two peaks …