Engineering Commons^™

Rational Design Of Multifunctional Nanocatalysts For Environmental Remediation And Energy Conversion Technologies, Md Ariful Ahsan

Open Access Theses & Dissertations

The discovery of efficient and sustainable carbon-based nanotechnologies to solve both the scarcity of drinking water and global energy crisis has become a paramount task in the last decades. Owed to the fast population growth and industrialization of the modern society, access to potable water and clean energy technologies is becoming very hard around the globe. Water pollutants have become a serious threat to the environment and ecology because of their toxic nature. Parallelly, the current hydrocarbon-based fuel industries are generating high levels of contamination across the planet, making imperative the development of cleaner energy technologies. In this regard, the …

Incorporation Of Zinc In Pre-Alloyed Cuin[Zn]S2/Zns Quantum Dots, Jean Carlos Morales Orocu

Graduate Theses and Dissertations

Since the early 2000s heavy-metal-free quantum dots (QDs) such as CuInS2/ZnS have attempted to replace CdSe, their heavy-metal-containing counterparts. CuInS2/ZnS is synthesized in a two-step process that involves the fabrication of CuInS2 (CIS) nanocrystals (NCs) followed by the addition of zinc precursors. Instead of the usual core/shell architecture often exhibited by binary QDs, coating CIS QDs results in alloyed and/or partially alloyed cation-exchange (CATEX) QDs. The effect that zinc has on the properties of CIS NCs was studied by incorporating zinc during the first step of the synthesis. Different In:Cu:Zn ratios were employed in this study, maintaining a constant 4:1 …

Scalable Synthesis Of Alumina Nanowires By Wet Chemical Method., Luis N Moreno

Electronic Theses and Dissertations

To satisfy an increasing demand for large-scale processes for producing alumina nanomaterials, a wet chemical method was evaluated. A potassium salt precursor was combined with aluminum to produce alumina – based nanowires. Compared with current methods such as thermal oxidation, sol-gel, and laser ablation, this method is highly scalable due to relatively low energy requirements and the ability to carry out the primary reaction under ambient conditions. The nanowire samples were evaluated using SEM, XRD, BET, and TEM to confirm morphology, phases present, and surface area. A porous nanowire structure was confirmed which has a BET surface area of 324.6 …

Lubrication Performance Of Vegetable Oils Modified With Halloysite Clay Nanotubes (Hnt) As Lubricant Additives, Md Abu Sayeed Biswas

Theses and Dissertations

Vegetable oil-based nano-lubricants are a great alternative to petroleum-based lubricants because of their less adverse impact on the environment. This work evaluates the tribological performance of sunflower, corn, and peanut oils modified with halloysite clay nanotubes (Al2Si2O2(OH)2nH2O) as lubricant additives at different concentrations. To analyze the tribological performance of the nano-lubricants, a block-on-ring tribometer was used following the ASTM G-077-17 standard procedure. Characterization of HNT was carried out by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA). The effect of the HNT on the lubrication performance of the newly developed vegetable oil-based nano-lubricants was evaluated, and the …

Development Of Vegetable Oil-Based Nano-Lubricants Using Montmorillonite Clay (Mmt) Nanoparticles As Lubricant Additives, Md Mashfiqur Rahman

Theses and Dissertations

Because of the environmental impact and price volatility, there has been a growing concern on the use of petroleum-based lubricants. This issue has stimulated research into the development of biodegradable lubricants like vegetable oils. In this study, the tribological and rheological behavior of sunflower, peanut, and corn oils modified with Montmorillonite nanoclay (MMT) as lubricant additives were evaluated at various concentrations. A custom-made block on ring tribotester was used to evaluate the wear and friction characteristics of the nano-lubricants, following the ASTM G-077-05 standard. The effects of concentration and shear rate on shear viscosity were studied using a parallel plate …

Chitosan Graphene Composite Fabrication And Characterization For Treatment Of Harmful Algal Blooms And Toxins, Sarah Zetterholm

Master's Theses

Chitosan graphene composites were fabricated and characterized as a management strategy for harmful algal blooms (HABs) caused by various species of cyanobacteria. These chitosan graphene materials were compared to previously studied chitosan graphene-oxide composites in both material properties and HAB treatment. In previous studies, adsorption of the cyanobacteria onto the surface of the composite materials has been observed. Investigations of the pure materials for these composites are also included in this study to determine whether removal is a result of charge interactions with the composite, or as an inherent property of the graphene or graphene oxide. Initial results suggest that …

Design And Development Of 2d Functional Semiconductor Nanocrystals, Andrew Hunter Davis

Dissertations - ALL

Anisotropic nanocrystals (NCs) have become of keen interest in recent years, especially for applications in optoelectronic devices due to their directionally oriented emissions, narrow emission spectra, and suitable morphologies for device integration. Of the desired anisotropic NCs, two-dimensional (2D) NCs are of profound interest, due to their impressive optical and electronic properties as well as their prospective advantages towards applications in layered optoelectronic devices, such as solar cells. However, 2D NCs face many challenges, including limited synthetic derivation, as well as decreased stability and optical response, due to their large surface-to-volume ratio and reactive planar surface increasing surface defect state …

Understanding Heterostructure Chemiresistive Gas Sensing At Room Temperature, Yale Wang

Theses and Dissertations

Chemiresistive sensors are the most widely investigated gas sensors due to their ease in fabrication, cost-effectiveness, simplicity of operation, and offer advances in miniaturization. Up to date, typical and well-researched resistive-type sensing materials include semiconductor metal oxides, noble metals, carbon-based nanomaterials (e.g., graphene and carbon nanotubes), and conducting polymers. Gas sensors based on a single material were found difficult to meet the practical requirements for multi-sensing properties, including sensitivity, selectivity, speed of response/recovery, stability, limit of detection, and room temperature operation. Rational design through a combination of chemically or electronically dissimilar nanomaterials is an effective route to enhancing gas sensing …

Analysis And Optimization Of A Colorimetric Nanosensor For Rapid Detection Of Escherichia Coli In Water, Sarah M. Stabler

Master's Theses

Safe drinking water is essential for life, yet at least two billion people around the world consume water contaminated with pathogens among other pollutants. Standard methods like polymerase chain reaction (PCR) and membrane filtration have been developed to detect enteric pathogens in water. However, these methods are limited in their accessibility due to long wait times to obtain results, and the requirements of skilled expertise, electricity, and laboratory equipment. This research has focused on addressing some of these limitations by analyzing the mechanisms of work and optimizing an indirect colorimetric nanosensor developed in previous research. The colorimetric nanosensor investigated herein …

Effect Of Dopants On The Properties And Performance Of Gallium Oxide: Bulk Ceramics And Nanomaterials, Vishal Bhimrao Zade

Open Access Theses & Dissertations

A comprehensive investigation performed in order to understand the fundamental aspects of transition metal (TM) incorporation into Ga2O3, a wide band gap semiconductor with a huge potential for application in electronics, optics, micromechanics and optoelectronics. An approach is presented to tailor the structural, optical, electrical, mechanical properties of Ga2O3 ceramics and thin films. The tungsten (W) mixed Ga2O3 with variable W at% (Ga2-2xWxO3 ; 0.00 ≤ x ≤ 0.30) were synthesized by the high temperature solid state route involving a 2-step calcination process. The solubility limits and phase stability of the compounds are established. While solubility and phase stability occur …

Oxone® Mediated Tempo-Oxidized Cellulose Nanomaterials: Material Characterization, Ultrafiltration Membrane Separations, And Thin Film Composite Gas Transport Analysis, John Phillips Moore

Graduate Theses and Dissertations

Cellulose nanomaterials (CNMs) are derived from plant matter and are comprised of nanoscopic cellulose crystals and fibers. They have a diverse set of applications, from cosmetics to oil recovery. This study focuses on the properties of Oxone® mediated TEMPO-oxidized cellulose nanomaterials (OTO-CNMs) and their use in controlling the transport properties of polymeric substrates. Synthesis and characterization of cellulosic nanoparticles have resulted in the creation of OTO-CNMs with properties that increase hydrophilicity. With added hydrophilicity, OTO-CNMs possess lower fouling propensity, making them ideal membrane additive for transport limited separations such as hemodialysis.

To utilize the material and unique properties thereof, this …