Digital Commons Network^™

The Cooperative Effects Of Channel Length-Bias, Width Asymmetry, Gradient Steepness, And Contact-Guidance On Fibroblasts’ Directional Decision Making, Quang Long Pham

Dissertations

Cell migration in complex micro-environments, that are similar to tissue pores, is important for predicting locations of tissue nucleation and optimizing scaffold architectures. Firstly, how fibroblast cells - relevant to tissue engineering, affect each other’s directional decisions when encountered with a bifurcation of different channel lengths was investigated. It was found that cell sequence and cell mitosis influence the directional choices that the cells made while chemotaxing. Specifically, the fibroblasts chose to alternate between two possible paths - one longer and the other shorter - at a bifurcation. This finding was counter-intuitive given that the shorter path had a steeper …

Experimental And Numerical Characterization Of Multiphase Subsurface Oil Release, Feng Gao

Dissertations

Subsurface oil release is commonly encountered in the natural environment and engineering applications and has received the substantial attention of researchers after the disastrous Deepwater Horizon Blowout oil spill in 2009. The main focus on the present research is to systematically study the hydrodynamics of underwater oil jet under a variety of conditions, including the effect of dispersant and different gas to oil ratios (GOR) by using experimental measurement as well as a Computational Fluid Dynamics (CFD) approach, from which the measured turbulent characteristics (e.g., velocity, turbulent kinetic energy, turbulence dissipation rate, etc.) of underwater oil jet are thoroughly examined …

Overcoming Conventional Modeling Limitations Using Image- Driven Lattice-Boltzmann Method Simulations For Biophysical Applications, Olufemi E. Kadri

Dissertations

The challenges involved in modeling biological systems are significant and push the boundaries of conventional modeling. This is because biological systems are distinctly complex, and their emergent properties are results of the interplay of numerous components/processes. Unfortunately, conventional modeling approaches are often limited by their inability to capture all these complexities. By using in vivo data derived from biomedical imaging, image-based modeling is able to overcome this limitation.

In this work, a combination of imaging data with the Lattice-Boltzmann Method for computational fluid dynamics (CFD) is applied to tissue engineering and thrombogenesis. Using this approach, some of the unanswered questions …

Screen Printed Moisture Sensor On Barrier Coated Sbs Board: The Characterizations Of The Hemicellulose-Based Biofilms And Their Applications For Smart Packaging, Ruoxi Ma

Dissertations

Fiber-based packaging materials have many advantages over their petroleum-based plastic competitors, such as sustainability, recyclability and stiffness/weight ratio. However, the poor barrier properties and sensitivity towards moisture are the main challenges for their extended use. Therefore, there has been a need to provide a biodegradable and biocompatible biopolymer packaging material with improved barrier properties for food and pharmaceutical packaging. Also, the moisture loss/gain problem causes a lot of waste every year. Therefore, there is a need of better tracking and sensing methods attached to the package in order to control the moisture level along the supply chain. To accomplish these …

Polymer Nanocomposites Containing High Aspect Ratio Particulates: Innovation In Co-Extruded Multilayer Barrier Films, Kevin Meyers

Dissertations

Delaminated montmorillonite (MMT) clay/ maleic anhydride grafted LLDPE nanocomposite multilayer films with alternating layers of LDPE were produced through multilayer co-extrusion. The MMT concentration within the nanocomposite layers was increased through annealing the films in the melt due to a mismatch in interdiffusion rates of the polymer layers. Analysis of the nanocomposite layers upon annealing revealed that the platelets impinged upon one another resulting in significant improvement in oxygen barrier in the multilayer system, exceeding the results of bulk nanocomposites.

Model analysis demonstrated that increasing the nanoplatelet aspect ratio or initial concentration in the filled layers would lead to even …

Combustion Of Nanocomposite Thermite Powders, Ian Monk

Dissertations

This work investigates combustion of nanocomposite thermite powders prepared by arrested reactive milling (ARM). The focus is on how ARM as a top-down approach to nano-thermite building generating fully-dense nanocomposite particles with dimensions of 1-100 µm affects the rates and mechanism of their combustion. A variety of thermites are milled using both aluminum and zirconium as fuels combined with several oxidizers (WoO₃, MoO₃, CuO, Fe₂O₃, and Bi₂O₃). The powders are ignited using both an electrostatic discharge (ESD) and a CO₂ laser beam.

A range of parameters vary …