Engineering Commons^™

Fabrication Of Silver-Doped Zinc Oxide Thin Films Through Optimized Sol-Gel Deposition And Nanoparticle Wetting Process, Reed T. Heintzkill

Theses and Dissertations

Zinc Oxide (ZnO) has been of significant interest as a Transparent Conductive Oxide (TCO) given its sizable direct band-gap, and as a potential substitute for Indium-Tin Oxide for use in opto-electronic and piezo-electric devices, due to its comparatively abundant and nontoxic precursor materials. Sol-gel processing is an easy, low-energy method for fabricating ZnO thin films, and there has been increasing interest in doping the compound such to give it p-type semiconductive character.

This thesis thoroughly investigates sol-gel processing of ZnO thin solid films, with focus on wet-chemistry (sol-gel) methods of doping the material with silver (both as elemental ions and …

In Silico Analysis Of Advanced Processing Methods For Light-Weight Alloys Powders, Marjan Nezafati

Theses and Dissertations

Light-weight Al and Mg-based metal-matrix nanocomposites (MMNCs) are lauded as one of the most promising structural materials for vehicle, military, and construction applications. These MMNCs are often synthesized using the powder metallurgy (PM) process under liquid nitrogen cryogenic environments to control the grain sizes. It is believed that proper incorporation of the nitrogen species into the bulk lattice during processing could strongly enhance the mechanical properties of MMNCs by forming N-rich dispersoids. In this work, using the density-functional theory (DFT), the adsorption, absorption and diffusion behavior of nitrogen molecule/atoms have been studied and related to t Al and Mg MMNC …

Synthesis And Performance Analysis Of Polyethersulfone (Pes) Nanocomposite Membrane Grafted With Functionalized Iron (Ii, Iii) Oxide Nanoparticles For Arsenate Removal, Jiyoung Rowley

Theses and Dissertations

Arsenic (As) is one of the detrimental elements in nature, which has negative effect on human health as well as the environment. High levels of arsenic concentration in the drinking water can cause skin, bladder, lung liver, and prostate, as well as cardiovascular, pulmonary, immunological, neurological and endocrine diseases. Arsenic pollution in the water has been reported in many countries as a worldwide problem, including the United States.

To develop a separation method for removing Arsenic, various treatment technologies including precipitation, coagulation with ferric chloride or aluminum sulfate coagulants, ion exchange and adsorption with modified nanocomposite material have been extensively …

Novel Engineered Porous Materials For The Removal Of Lead From Water, Mohsen Hajipour Hajipour Manjili

Theses and Dissertations

The estimated average blood lead level for the population younger than 5 years in the United States is approximately 100 times higher than ancient background levels, indicating that substantial sources of lead exposure exist in the environment. This research is focused on the removal of lead from water with a functionalized zeolite. Functionalization improves adsorption behavior to achieve adsorbent materials with high capacity and stability with potential multiple re-uses.

The lead sorption from water onto an Australian zeolitic mineral (clinoptilolite) unmodified and modified with sulfide-based reagents is investigated with batch and fixed bed column experiments. The effect of solution pH, …

Design Of Optimized Pes-Alumina Polymer Matrix Nanocomposite Membranes For Heavy Metal Ions Removal From Water, Behnam Gohari

Theses and Dissertations

Membrane filtration has become the focus of separation processes in different industries including water and waste water treatment. Synthetic asymmetric polymeric membranes are the most widely used membrane type for filtration technologies such as ultrafiltration, nanofiltration, and reverse osmosis due to better control of the pore forming mechanism, higher flexibility, lower cost, and ease of operation compered to inorganic membranes. Among the available polymers, polyethersulfones polymers (PES) demonstrate strong chemical and thermal stability, making them popular as basic materials for filtration and support materials for composite membranes. They are hydrophobic intrinsically and the application of such membranes is still limited …

Graphene-Based Lubrication For Tribological Applications: Nanolubricants And Self-Lubricating Nanocomposites, Emad Omrani

Theses and Dissertations

In this work, the effects of graphene nanoplatelets (GNPs) additives on tribological properties of aluminum are investigated. The objective of this research is to investigate and explain the enhancement mechanisms of GNPs at the contact surface during tribological testing. The graphene nanoplatelets are studied both as an oil additive (Chapter I) and as a reinforcement (Chapter II) experimentally. The coefficient of friction (COF) and wear rate were identified using a pin-on-disk test setup.

Mineral, organic, and synthetic oils are not always efficient enough to satisfy the demands of a high-performance lubricant; therefore, mixing additives with base fluids is an approach …

New Approaches To Multi-Functional Soft Materials, Seyedali Banisadr

Theses and Dissertations

Soft robotics is a relatively new, but fast-developing field of science and technology that utilizes soft materials such as polymers in their body structure. Despite significant progress in soft robotic devices, robots that can sense their environments are still very rare. Although some soft robots have exhibited sensing capabilities, they still have not demonstrated synergistic coupling of sensing and actuation. From our perspective, this type of coupling may take us one step closer to fabricate soft robots with autonomous feedback dynamics. In this work, we present new approaches to soft robotic devices, which are fabricated from responsive soft materials and …

Novel Solar Cells Based On Two-Dimensional Nanomaterials And Recycled Lead Components, Xiaoru Guo

Theses and Dissertations

To meet the rapidly growing demand for energy and reduce the use of dwindling fossil fuels, the efficient utilization of renewable energy is a constant pursuit globally. Because solar cells convert vastly available sunlight into electricity, developing high-performance and low-cost solar cells is a top strategy for future energy supply. Dye-sensitized solar cells (DSSCs) and perovskite solar cells (PSCs) are the most promising choices. In the meantime, highly concentrated sulfuric acids from retired lead-acid batteries become an environmental concern, and lead contamination in drinking water raises concerns in general public. This study addresses both above-mentioned problems by using two-dimensional (2D) …

Synthesis And Characterization Of Transition Metal Oxide And Dichalcogenide Nanomaterials For Energy And Environmental Applications, Ren Ren

Theses and Dissertations

Transition metal oxides (TMOs) and transition metal dichalcogenides (TMDs) have gained immense interest recently for energy and environmental applications due to their exceptional structural, electronic, and optical properties. For example, titanium dioxide (TiO2) as one of the TMO photocatalysts has been widely studied due to its stability, non-toxicity, wide availability, and high efficiency. However, its wide bandgap significantly limits its use under visible light or solar light. Recent studies also show that semiconducting TMDs could be used as potential supercapacitor electrode materials and platinum (Pt)-free electrocatalysts for economical utilization of renewable energy, because the high cost and scarcity of Pt …