Engineering Commons^™

Quantification Of Flows Emerging From Small Pores In Plane Walls, Matia Peter Edwards

Electronic Thesis and Dissertation Repository

Current membrane separation processes are limited in high production and high purity settings due to a trade-off between selectivity and permeance. Methods of creating nanoscale geometries in 2D materials are emerging and present an opportunity for fast, size selective mass transport that can be tailored to a wide array of applications. This thesis develops a method for quantifying flow through small pores in plane walls based on the behaviour of a solute dispersed in a downstream reservoir. This method is validated for a range of micropore diameters, for which flow rates can be calculated with confidence, and is shown to …

Mass Advection–Diffusion In Creeping Flow Through An Orifice Plate: A Model For Nanoporous Atomically Thin Membranes, Harpreet Atwal, Anika Wong, Michael Boutilier

Chemical and Biochemical Engineering Publications

Continuum transport equations are commonly applied to nanopores in atomically thin membranes for simple modeling. Although these equations do not apply for nanopores approaching the fluid or solute molecule size, they can be reasonably accurate for larger nanopores. Relatively large graphene nanopores have applications in small particle filtration and appear as unwanted defects in large-area membranes. Solute transport rates through these nanopores determine the rejection performance of the membrane. Atomically thin membranes commonly operate in a regime where advection and diffusion both contribute appreciably to transport. Solute mass transfer rates through larger nanopores have previously been modeled by adding continuum …

Synthesis And Drop-On-Demand Deposition Of Graphene Derivative Inks For Flexible Thin Film Electronics, Dogan M. Sinar

Electronic Thesis and Dissertation Repository

This dissertation presents methods for deposition and post-processing of Graphene-Carboxymethyl Cellulose (G-CMC) and Graphene Oxide (GO) aqueous functional inks using a custom drop-on-demand (DOD) printer to fabricate mechanically flexible, non-transparent and transparent thin film electronic devices. Thin films on flexible substrates find use in lightweight, low profile, and conformable electronic devices. Such devices can include chemical sensors, flexible RFID tags, bioelectronics circuits, lightweight electronics for space systems, and transparent electrodes for optoelectronic systems. The goal of this research project is to provide simple methods for fabrication of these devices using environmentally friendly and easy to synthesize functional inks. Therefore, two …

Fabrication And Characterization Of Hybrid Nanocomposites By Matrix Assisted Pulsed Laser Evaporation, Songlin Yang

Electronic Thesis and Dissertation Repository

Different methods have been applied to deposit hybrid nanocomposites which can be applied in various fields due to their light weight and multifunctional properties. Here, matrix assisted pulsed laser evaporation (MAPLE) equipment with 532 nm Nd:YAG laser is applied to fabricate three types of hybrid nanocomposites on different substrates.

Chemical synthesized FeCo nanoparticles were deposited on graphene sheets by MAPLE technique (laser fluence: 300 mJ/cm²). The effects of deposition time (t) on particle amount, shape and size have been investigated. Yttrium barium copper oxide (YBCO) materials are one type of high-temperature superconductive materials and …

Nanostructured Tin-Based Anodes For Lithium Ion Batteries With X-Ray Absorption Fine Structure Studies, Dongniu Wang

Electronic Thesis and Dissertation Repository

The practical applications of lithium ion batteries are highly dependent on the choice of electrodes, where boosting the materials innovations to design and achieve high capacity, excellent cycling performance, rate capability, low-cost and safe electrode materials provide the best solution. Based on this, tin-based anodes have gained great attention due to its high theoretical capacity, low cost and nontoxic nature to environment. Nevertheless, it undergoes significant volume variation(259%)during the operation of the battery, leading to pulverization and significant capacity fade. Thus, the practical application of tin-based anodes is still quite challenging. This thesis tackles issues related to tin-based anodes. It …

Development Of Nanostructured Limpo4 (M=Fe, Mn) As Cathodes For High Performance Lithium-Ion Batteries, Jinli Yang

Electronic Thesis and Dissertation Repository

Olivine LiFePO₄ has garnered the most interest because of its environmental benignity, high safety and theoretical capacity. However, the major limitation for LiFePO₄ is the intrinsically poor electronic conductivity and ionic conductivity. The sluggish kinetics for LiFePO₄ could be overcome by reducing the size, coating with conductive carbon, or doping with isovalent ions. The decrease of the size to nanoscale could shorten the diffusion time of Li ions in LiFePO₄ during intercalation/deintercalation process, but the nano-size active material usually accompanies with low tap density. Carbon coating and carbon addition could alleviate the poor electronic conductivity. However, …

Nano Tio2/Graphene Composites For Photovoltaic And Photocatalytic Materials, Nasrin Farhangi

Electronic Thesis and Dissertation Repository

Graphene has been recognized as one of the most exciting carbon based materials of the present decade due to its unique electronic, mechanical and thermal properties. High surface area exfoliated graphene sheets with controllable surface functionality is an attractive two-dimensional surface for attaching different metals and semiconductors for improving the performance of catalysts, sensors, photoelectronic and energy conversion devices. Graphene is an ideal material which can be used for improving various metal oxide properties such as those of titania (TiO₂). TiO₂/graphene composites have shown excellent properties compared to bare TiO₂ in various applications. In high …