Master of Science in Civil Engineering, Cleveland State University, 2017, Washkewicz College of Engineering

The underlying mechanisms of pile setup in clay soil was investigated in the context of electrokinetics. Load-displacement tests were done at 0, 1, 3, 5 and 10 day intervals on eleven bench scale Stainless Steel friction piles embedded in compacted natural and kaolinite clay soils to determine setup. Measurements confirmed that the pile capacities increased with time indicating occurrence of setup. The correlations of the measured pile setup with electric self-potential, zeta potential as well as the plastic limit, liquid limit and plasticity index of the soils were investigated. For kaolinite clay, a moderate positive correlation was observed between pile setup and the electric gradient in the soil. The zeta potentials of the soils were calculated from measured electroosmotic flows. It was shown that the zeta potentials had a moderate correlation with setup in kaolinite clay. The results indicated that electrokinetic phenomena could be the major contributing factor for pile setup in clay soils. A moderate positive correlation was observed between the time dependent pile capacity and the liquid limit of kaolinite. No correlation was observed between pile capacity and the plastic limit of the soil. A case of pile relaxation was observed in this study that suggested that a soil with favorable properties for setup may exhibit relaxation instead of setup due to disturbances during pile installation.

Committee: Lutful Khan Ph.D. (Committee Chair); Mehdi Jalalpour Ph.D. (Committee Member); Jacqueline Jenkins Ph.D. (Committee Member) Subjects: Civil Engineering

Doctor of Philosophy, Case Western Reserve University, 2010, EECS - Electrical Engineering

Microfabricated silicon nanoporous membranes (SNM) are a breakthrough technology with potential in biomedical applications that include, but are not limited to, artificial organs, drug delivery, cell encapsulation, and water purification. SNM have a number of highly advantageous characteristics when compared to polymer filters commonly used in such applications, such as increased chemical and mechanical stability. The characteristic of greatest interest, however, is the monodisperse pore size distribution achieved by the sacrificial removal of a highly controlled silicon oxide layer grown by thermal oxidation. The monodisperse pore size distribution allows for a greater level of characterization of pore and membrane behavior than would otherwise be possible. As such, investigations into the transport and electrical properties of SNM as a whole can be interpreted as an aggregate of individual pores. This work explores the electrical properties of the solution-pore interface via the streaming potential. This is followed by investigations of the size-based and charge-based filtration characteristics of the SNM using fluorescently labeled neutral and anionic Ficoll, a polysaccharide with low asymmetry. Finally, SNM are employed in the removal of endotoxin from an aqueous solution, a critical process in the production of medical grade water.

Committee: Christian Zorman PhD (Committee Chair); Aaron Fleischman PhD (Committee Co-Chair); Francis Merat PhD (Committee Member); Miklos Gratzl PhD (Committee Member) Subjects: Electrical Engineering

Master of Science (MS), Ohio University, 2023, Civil Engineering (Engineering and Technology)

Tire particles (TP) are the largest source of microplastics in nature. However, the adsorption behavior of TP needs to be better understood. TP used in this study were generated from cryo-milling and aged with 30% nitric acid. Single and competitive adsorption isotherm experiments were conducted to investigate the potential of TP as carriers of heavy metals. Langmuir and Freundlich models were used to analyze adsorption data. Competitive adsorption demonstrated a reduction in the adsorption capacity of TP. The preference for lead to copper by TP was explained by the physical and chemical properties of the metals. The adsorption capacity was maximum at the pH range of 6-12 for lead, and for copper, it was pH 10. pH, zeta potential, FT-IR, and XPS results indicated that electrostatic attraction and surface complexation were involved in the heavy metal adsorption on TP.

Committee: Lei Wu Dr. (Advisor); Natalie Kruse-Daniels Dr. (Committee Member); Daniel Che Dr. (Committee Member); Guy Riefler Dr. (Committee Member) Subjects: Environmental Engineering

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

MS, University of Cincinnati, 2010, Engineering and Applied Science: Mechanical Engineering

The increasing heat generation rates produced by very large scale integration (VLSI) devices require more sophisticated heat removal systems to replace the macroscopic fin-array heat sinks. The goal of this research is to design, fabricate, and test an actively cooled micro-channel heat sink device that can achieve high-heat dissipation rate with a reduced chip-backside volume. An experimental setup was assembled and Electro-Osmotic Flow (EOF) was used. An increase in the cooling fluid (buffer) temperature of 3.7 °C, 11.4 °C, and 20.7 °C was achieved for 315.8 W/m2, 1008.8 W/m2, and 1842.1 W/m2 heat flux values, respectively. A flow rate of 82 µL/ min was achieved at 400 V of applied EOF voltage. The maximum increase in the cooling fluid temperature due to the joule heating was 4.5 °C for 400 V of applied EOF voltage. Heat transfer coefficient (h) was plotted along the non-dimensional length of the channel; it reached a maximum of 292 W/m2.K at the channel inlet and decreased to reach 92 W/m2.K at the channel outlet. Numerical calculations of temperatures and flow were conducted and the results were compared to experimental data. It was found that using a shorter channel length and an EOF voltage in the range of 400 – 600 V allows application of a heat flux in the order of 104 W/m2. For elevated voltages, the velocity due to EOF increased, leading to an increase in total heat transfer for a fixed duration of time; however, the joule heating also got elevated with increase in voltage.

Committee: Rupak Banerjee PhD, PE (Committee Chair); Teik Lim PhD (Committee Member); Ajit Roy PhD (Committee Member) Subjects: Mechanical Engineering

Master of Sciences (Engineering), Case Western Reserve University, 2008, Materials Science and Engineering

Single-crystal silicon wafers, with and without self-assembled organic monolayersurface treatments (amine or sulfonate) were immersed in commercially available oxide nanoparticle suspensions (alumina, ceria, or titania). These specimens allowed the study of the interactions of oxide nanoparticles with functionalized substrates in the presence of a non-reactive aqueous liquid. They therefore represented models of chemical bath deposition (CBD) and liquid-phase deposition (LPD) processes, with the difference that the model systems lacked the continually changing pH, concentration, and particle number and size distributions typical of most CBD and LPD processes. Electrostatic arguments were used to predict the ability of the nanoparticle suspensions to deposit continuous films on functionalized substrates. These predictions were based on the simple assumption that a pH value of the suspension between the isoelectric point (IEP) of the particle and the IEP of the functionalized substrate would provide surfaces of opposite charge and provide the necessary attractive force to initiate film growth. These predictions were correct in 15 of 18 specimens studied, including positive and negative outcomes over the three different oxides and three different substrates. All sample depositions were investigated with x-ray photoelectron spectroscopy (XPS) to determine elemental composition at the surface, atomic force microscopy (AFM) for topographic observation, nanoscratch for thickness determination and scanning electron microscopy (SEM) for morphology. Successful film thicknesses ranged from 6.1 nm to 53 nm over deposition times of 15 and 30 h. Results were compared with literature data from chemical bath deposition. While the nanoparticle suspensions may serve as a suitable model for early CBD film deposition, it is conjectured that the non-reacting suspensions do not possess the means to sustain continued film growth. 6

Committee: Mark De Guire R (Advisor); James McGuffin-Cawley PhD (Committee Member); Harold Kahn PhD (Committee Member) Subjects: Materials Science