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Stenger, Dillon MichaelDependency of Aluminum Nanoparticle Flash Ignition on Sample Internal Water Content and Aggregation
Master of Science (M.S.), University of Dayton, 2016, Aerospace Engineering
The United States Air Force believes that hypersonic flight opens a multitude of possibilities for the warfighter. One of the main propulsion systems for hypersonic flight is scramjet engines. These engines are currently ignited using a form of electric discharge and a primer fuel. This primer fuel system takes away valuable volume and weight in hypersonic vehicle designs. One alternative ignition method would be the utilization of plasmonic resonance to flash ignite aluminum nanoparticles. This process had been proven multiple times in the past and research has begun on characterizing how this ignition process can be affected. One that has not been researched to date has been how water content and agglomeration affect the energy needed for ignition to be achieved. To understand this functional dependence, aluminum nanoparticles were put through a series of trials with various levels of water content. Samples of particles were heated at 473.15 K to decrease water content and subsequently tested to determine the energy input needed for ignition. To understand the effects of increasing water content, particles were placed in an environment with at least 100% relative humidity for both 48 and 168 hours and then tested to determine the ignition energy needed. The results from the two humidified cases were compared with the data from a control group whose water content was not altered in a controlled manner. It was determined that by humidifying the particles the minimum energy needed for total ignition was lowered by approximately five percent on average while drying the particles increased the energy needed by approximately four percent on average.

Committee:

Aaron Altman, PhD (Advisor); Timothy Ombrello, PhD (Advisor); David Myszka, PhD (Committee Member)

Subjects:

Aerospace Engineering; Engineering; Nanoscience

Keywords:

Aluminum Nanoparticle Flash Ignition; Nanoparticle Aggregation; Nanoparticle Internal Water Content; Alternate Engine Ignition System

Ducay, Rey Nann Mark AbaqueDirect Detection of Aggregates in Turbid Colloidal Suspensions
Master of Science, Miami University, 2015, Physics
This thesis presents the application of an empirical model of total internal reflection (TIR) we recently developed in conjunction with a home-built sensor to detect nanoaggregates in highly scattering opaque polystyrene colloidal suspensions. The nanoaggregates are detected directly without any sample dilution or special sample preparation. Additional results on nanoaggregate detection in gold nanoparticle suspensions are presented. Preliminary tests of our model and sensor in an absorbing dye solution are also presented.

Committee:

Samir Bali, PhD (Advisor); Lalit Bali, PhD (Advisor); Jason Berberich, PhD (Advisor); Jon Scaffidi, PhD (Advisor); James Clemens, PhD (Committee Member); Karthik Vishwanath, PhD (Committee Member)

Subjects:

Analytical Chemistry; Biochemistry; Biomedical Engineering; Biomedical Research; Biophysics; Chemical Engineering; Chemistry; Experiments; Materials Science; Medical Imaging; Molecular Physics; Molecules; Nanoscience; Nanotechnology; Optics; Organic Chemistry; Physics; Polymer Chemistry; Polymers; Scientific Imaging

Keywords:

Nanoparticles; nanoparticle aggregation; empirical model; gold nanoparticles; polystyrene nanoparticles; microspheres; turbid media; TIR; total internal reflection; biosensors; highly-scattering; nanoaggregation sensing; DLS; UV-Vis; DLVO; Zeta potential

Sharma, MonitaSimulating hemodynamics in in vitro culture models: Implications on Nano-biointeractions
Doctor of Philosophy (PhD), Wright State University, 2013, Biomedical Sciences PhD
Gold nanoparticles (Au-NPs) have demonstrated great potential in the development of a variety of tools with applications ranging from biomedical to military fields. Consequently, there is increasing concern regarding the toxic potential of these nanomaterials. Biodistribution studies demonstrate clearance of Au-NPs from peripheral circulation and bulk localization primarily in the liver and spleen post- intravenous administration. Deposition of Au-NPs in spleen suggests the potential for direct exposure of immune cells to these foreign materials under relatively static conditions. Although much less, due to the Blood Brain Barrier (BBB), Au-NPs appear to also deposit in the brain, suggesting that the resident cells of the brain may also be exposed to Au-NPs. Studies show the toxic potential of Au-NPs in a variety of cell types, however, the overall picture is still inconclusive due to the variation in cell-to-cell responses to these NPs. Additionally, NP aggregation and sedimentation in static in vitro conditions makes it very difficult to achieve uniformly dispersed treatment solutions. Furthermore, static conditions might be physiologically relevant to certain cell types, such as the immune cells in the spleen and lymph nodes; however the `BBB’ experiences continuous flow of blood. Therefore, NP research calls for modification of traditional in vitro models to simulate the in vivo conditions. The main aim of this study was to determine the impact of Au-NPs on two model systems; 1) a B-lymphocyte cell line (CH12.LX) which pose as a direct target to NPs in vivo and 2) a co-culture of an astrocytic (C8-D30) and an endothelial cell line (bEnd.3), where endothelial cells shield the astrocytic cell line from direct exposure to NPs. Furthermore, static conditions might be physiologically relevant to certain cell types, such as the immune cells in the spleen and lymph nodes; however the `BBB’ experiences continuous flow of blood. Our results demonstrate that treatment with Au-NPs lead to altered B-cell function, in terms of increased antibody expression, but no change in astrocytic and endothelial cell function was observed in terms of the inflammatory cytokine release. This might suggest that Au-NPs might exhibit differential response in different cell types which further emphasizes the need of careful evaluation of NPs before in vivo use. Furthermore, we observed decrease in agglomeration and deposition under flow conditions in comparison to static in vitro conditions suggesting improvement of traditional in vitro models to simulate the in vivo conditions.

Committee:

Courtney Sulentic, Ph.D. (Committee Co-Chair); Saber Hussain, Ph.D. (Committee Co-Chair); Nancy Bigley, Ph.D. (Committee Member); Sharmila Mukhopadhyay, Ph.D. (Committee Member); David Goldstein, Ph.D. (Committee Member)

Subjects:

Biomedical Research; Nanoscience; Nanotechnology

Keywords:

Gold Nanoparticles, Blood Brain Barrier, B cells, NF-Kappa B, Shear flow, Nanoparticle aggregation