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Full-Text Articles in Engineering

Designing The Electrode Geometry And Electrolyte To Enhance The Product Selectivity And Activity In Carbon Dioxide Electroreduction, Samaneh Sharifi Golru Jun 2022

Designing The Electrode Geometry And Electrolyte To Enhance The Product Selectivity And Activity In Carbon Dioxide Electroreduction, Samaneh Sharifi Golru

Dissertations, Theses, and Capstone Projects

Excessive utilization of the fossil fuels due to the rapid growth of the global population has resulted in a dramatic increase in the carbon dioxide (CO2) level in the atmosphere which is the main reason for global warming and climate change. Therefore, green technologies are in high demand to develop carbon-neutral energy cycles. In this regard, CO2 electroreduction (CO2ER) has been proposed as a promising approach for CO2 utilization. CO2ER can mitigate the CO2 level in the atmosphere as well as produce value-added chemicals and fuels at ambient conditions. Despite the benefits of CO2 …


Tools And Strategies For The Patterning Of Bioactive Molecules And Macromolecules, Daniel J. Valles Sep 2021

Tools And Strategies For The Patterning Of Bioactive Molecules And Macromolecules, Daniel J. Valles

Dissertations, Theses, and Capstone Projects

Hypersurface Photolithography (HP) is a printing method for fabricating structures and patterns composed of soft materials bound to solid surfaces and with ~1 micrometer resolution in the x, y, and z dimensions. This platform leverages benign, low intensity light to perform photochemical surface reactions with spatial and temporal control of irradiation, and, as a result, is particularly useful for patterning delicate organic and biological material. In particular, surface- initiated controlled radical polymerizations can be leveraged to create arbitrary polymer and block- copolymer brush patterns. Chapter 1 will review the advances in instrumentation architectures from our group that have made these …


Nature-Inspired Electrode Materials For Next Generation Sustainable Energy Storage, Mikhail Miroshnikov Jun 2020

Nature-Inspired Electrode Materials For Next Generation Sustainable Energy Storage, Mikhail Miroshnikov

Dissertations, Theses, and Capstone Projects

Despite revolutionizing the world of portable electronics, the contemporary lithium-ion battery (LIB) suffers from challenges associated with the cost, safety, and environmental impact of transition metal oxide-based intercalation cathodes. To alleviate these issues, naturally occurring organic molecules may serve as sustainable alternatives to traditional inorganic cathode materials. The electrochemical properties of organic compounds are derived from redox-active functional groups containing oxygen, nitrogen and sulfur. Additionally, these functional groups are capable of coordinating metal ions beyond lithium, allowing for compatibility with sodium-ion batteries (SIBs) and other earth abundant metal-based energy storage systems. However, despite competitive performance against commercialized cathode materials, much …


Renal Specific Rnai Delivery By Fibrillar Nanoparticle Excipients, Sam Wong Sep 2019

Renal Specific Rnai Delivery By Fibrillar Nanoparticle Excipients, Sam Wong

Dissertations, Theses, and Capstone Projects

RNA interference (RNAi) is a powerful tool to manipulate the phenotype of an organism by silencing the expression of specific genes and is viewed as a highly promising platform for treating undruggable targets and disorders where small molecule drugs and antibodies would fail. However, development of RNAi based therapies has faced major barriers including cellular and tissue-specific uptake of the Small Interfering RNA (siRNA). Utilizing different nanoparticles as RNAi excipients, cellular uptake and gene silencing potency can be greatly improved. The research in Dr. McDevitt groups has fibrillar carbon nanotubes (CNT) as carriers for siRNA for gene silencing in vitro …


Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity, Wanlu Li Feb 2018

Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity, Wanlu Li

Dissertations, Theses, and Capstone Projects

For the first-time sulfur-doped, nitrogen-doped and sulfur, nitrogen-codoped nanoporous carbons were systematically studied as catalysts for CO2 electrochemical reduction reaction (CO2ERR). The Faradaic efficiencies (FE) of CO and CH4 formation were calculated to evaluate the performance of these carbons. The best catalysts showed the FE of CO and CH4 formation of 29% and 0.76%, respectively. It was found that the overall performance in CO2ERR dramatically increased upon the reduction pretreatment of the carbons in N2-saturated electrolyte before the CO2 reduction process. The pretreated carbon showed the maximum FE of CO …


Dynamics Of Nanoparticles In Fluids And At Interfaces, Weikang Chen Oct 2014

Dynamics Of Nanoparticles In Fluids And At Interfaces, Weikang Chen

Dissertations, Theses, and Capstone Projects

In this thesis, we use molecular dynamics simulation to study three basic behaviors or properties of nanoparticles: deposition during droplets evaporation, slip boundary condition and Brownian motion. These three problems address the need for an in-depth understanding of the dynamics of nanoparticles in fluids and at interfaces. In the first problem, evaporation of the droplets dispersed with particles, we investigated the distribution of evaporative flux, inner flow field, density and temperature. And we use these numerical experiments to check on our hydrodynamic theory of the "coffee ring" phenomenon. The simulations reveal the connection between the particle interactions and the deposit …


Magnetic Janus Particles And Their Applications, Bin Ren Feb 2014

Magnetic Janus Particles And Their Applications, Bin Ren

Dissertations, Theses, and Capstone Projects

Magnetic properties are important since they enable the manipulation of particle behavior remotely and therefore provide the means to direct a particle’s orientation and translation. Magnetic Janus particles combine magnetic properties with anisotropy and thus are potential building blocks for complex structures that can be assembled from a particle suspension and can be directed through external fields. In this thesis, a method for the fabrication of three types of magnetic Janus particles with distinct magnetic properties is introduced, the assembly behavior of magnetic Janus particles in external magnetic and electric fields is systematically studied, and two potential applications of magnetic …


Hydrodynamic And Mass Transport Properties Of Microfluidic Geometries, Thomas F. Leary Feb 2014

Hydrodynamic And Mass Transport Properties Of Microfluidic Geometries, Thomas F. Leary

Dissertations, Theses, and Capstone Projects

Microfluidic geometries allow direct observation of microscale phenomena while conserving liquid volumes. They also enable modeling of experimental data using simplified transport equations and static force balances. This is possible because the length scales of these geometries ensure low Re conditions approaching the Stokesian limit, where the flow profile is laminar, viscous forces are dominant and inertial forces are negligible. This work presents results on two transport problems in microfluidic geometries. The first examines the heterogeneous binding kinetics in a microbead array, where beads with different chemical functionalities are sequentially captured in a well geometry over which analyte solution is …


Synergistic Surfactant Interactions And The Consequences On Phase Behavior, Interfacial Tension Reduction And Hydrophobic Surface Wetting, Makonnen Mateós Payne Jan 2008

Synergistic Surfactant Interactions And The Consequences On Phase Behavior, Interfacial Tension Reduction And Hydrophobic Surface Wetting, Makonnen Mateós Payne

Dissertations, Theses, and Capstone Projects

The ability for some of the nonionic trisiloxane surfactants to completely and rapidly wet a hydrophobic surface has been well documented for several years. However, to date, the behavior of the trisiloxane surfactants at the solid-liquid interface is not yet completely understood, leading to an incomplete understanding of the mechanism for complete wetting. In this work we report our findings with regard to the synergistic interactions between polyethylene oxide surfactants of the general structure CiE j and compare the behavior to a known super wetting surfactant. Pendant drop tensiometry experiments and sessile drop contact angle measurements on hydrophobic surfaces were …