Engineering Commons^™

Utilizing Fluorescent Nanoscale Particles To Create A Map Of The Electric Double Layer, Quintus Owen

Theses and Dissertations

The interactions between charged particles in solution and an applied electric field follow several models, most notably the Gouy-Chapman-Stern model, for the establishment of an electric double layer along the electrode, but these models make several assumptions of ionic concentrations and an infinite bulk solution. As more scientific progress is made for the finite and single molecule reactions inside microfluidic cells, the limitations of the models become more extreme. Thus, creating an accurate map of the precise response of charged nanoparticles in an electric field becomes increasingly vital. Another compounding factor is Brownian motion’s inverse relationship with size: large easily …

Enhancement Of Energy Efficiency For Thermal Energy And Biomass Driven Applications, Osama Mansour Selim Elsayed

Theses and Dissertations

The importance of gas turbine blades is to convert the thermal energy into shaft work output, which makes the turbine blades are one of the critical components of the gas turbines. Besides the mechanical stresses caused by the centrifugal force and the fluid forces, the thermal stresses arise because of the temperature gradient within the blade materials. This paper aims to have a uniform circumferential temperature field at the combustor exit, consequently reducing the thermal stresses caused by the non-uniform temperature distribution along the turbine blade. The validation of the simulation results with the experiments showed an acceptable agreement with …

Study Of The Chemical Fabrication Process Of Nsom Probes And The Modification Of The Probe Surface, Muhammad Nazmul Hussain

Theses and Dissertations

Near-field scanning optical microscopy (NSOM) merges scanning probe technology with the power of high-resolution optical microscopy and provides a natural view into the nanoworld. NSOM requires tapered probes with subwavelength optical apertures and wide cone angles to efficiently channel the illumination light to the tip apex so that it can acquire optical images beyond the diffraction limit. Tapered probes with a range of cone angles can be fabricated through chemical etching of optical fibers using hydrofluoric acid (HF) by varying the etching time. Apart from their use for NSOM imaging, such optical probes can also be transformed into nanosensors by …

Functional Material Systems For Stimuli-Responsive Interference Coloration, Milad Momtaz

Theses and Dissertations

Part I: Responsive Interference Coloration (RIC) Systems for High-Performance Humidity Sensing

High-humidity conditions (85−100% relative humidity) have a variety of effects on many aspects of our daily lives. In spite of significant progress in the development of structural coloration-based humidity sensors, enhancing the sensitivity and visual humidity resolution of these sensors at high-humidity environment remains a big challenge. In this work, high-performance colorimetric humidity sensors based on environment-friendly konjac glucomannan (KGM) are introduced. These sensors are fabricated via thin-film interference and prepared using a simple, affordable, and scalable method. An effective approach is shown for markedly improving the sensitivity and …

Development Of An Advanced Zinc Air Flow Battery System (Phase 2), Jingyu Si

Theses and Dissertations

A zinc-air battery is the promising energy storage technology for large-scale energy storage applications due to its low cost, environmental friendliness, and high energy density. However, the electrically rechargeable zinc−air batteries suffer from poor energy efficiency and cycle life because of critical problems such as passivation, dendrite growth, and hydrogen evolution reaction. The proliferation of zinc−air batteries is limited.

The zinc-air flow battery combines the advantages of both a zinc-air battery and a redox flow battery. This combination permits the zinc-air flow battery to compete with the current leading battery technologies in the marketplace. A rechargeable Zn-air flow battery with …

Computational Materials Science And Engineering: Model Development And Case Study, Yihan Xu

Theses and Dissertations

This study presents three tailored models for popular problems in energy storage and biological materials which demonstrate the application of computational materials science in material system development in these fields. The modeling methods can be extended for solving similar practical problems and applications.

In the first application, the thermo-mechanical stress concentrated region in planar sodium sulfur (NaS) cells with large diameter and different container materials has been estimated as well as the shear and normal stresses in these regions have been quantified using finite-element analysis (FEA) computation technique. It is demonstrated that the primary failure mechanism in the planar NaS …

Optimizing Hydrogen Sulfide Removal And Biogas Production Using The Water Wash Method, Brian Leightner

Theses and Dissertations

Biogas forms from decomposing organic material in agricultural digesters, landfills, and wastewater treatment plant digesters. Biogas is mostly composed of methane, and can be used as a carbon-based fuel. Microorganisms that consume organics in these waste streams also produce hydrogen sulfide (H2S) as part of the biogas, in varying trace amounts. H2S is corrosive to engines and pipes for machinery, a human health hazard when inhaled, and an aquatic hazard when dissolved in water. Water washing is an absorption process that dissolves hydrogen sulfide and other water soluble compounds in this process and carries it away from the gas, thereby …

In Situ Chemical Probing Of Vacancy Defects In Graphene And Boron Nitride At Room Temperature, Ali Ihsan Altan

Theses and Dissertations

IN SITU CHEMICAL PROBING OF VACANCY DEFECTS IN GRAPHENE AND BORON NITRIDE AT ROOM TEMPERATURE

by

Ali Ihsan Altan

The University of Wisconsin-Milwaukee, 2019

Under the Supervision of Professor Jian Chen

Chemical vapor deposition (CVD) has emerged as the most promising technique towards manufacturing of large area, high quality graphene. Characterization, understanding, and controlling of various structural defects in CVD-grown graphene are essential to realize its true potential for real-world applications. We report a new method for in situ chemical probing of vacancy defects in CVD-grown graphene at room temperature. Our approach is based on a solid–gas phase reaction that …

In Situ Chemical Probing Of Vacancy Defects In Graphene And Boron Nitride At Room Temperature, Ali Ihsan Altan

Theses and Dissertations

IN SITU CHEMICAL PROBING OF VACANCY DEFECTS IN GRAPHENE AND BORON NITRIDE AT ROOM TEMPERATURE

by

Ali Ihsan Altan

The University of Wisconsin-Milwaukee, 2019

Under the Supervision of Professor Jian Chen

Chemical vapor deposition (CVD) has emerged as the most promising technique towards manufacturing of large area, high quality graphene. Characterization, understanding, and controlling of various structural defects in CVD-grown graphene are essential to realize its true potential for real-world applications. We report a new method for in situ chemical probing of vacancy defects in CVD-grown graphene at room temperature. Our approach is based on a solid–gas phase reaction that …

Active Polymeric Materials For 3d Shaping And Sensing, Adebola Oyefusi

Theses and Dissertations

Part I: Reprogrammable Chemical 3D Shaping for Origami, Kirigami, and Reconfigurable Molding

Origami- and kirigami-based design principles have recently received strong interest from the scientific and engineering communities because they offer fresh approaches to engineering of structural hierarchy and adaptive functions in materials, which could lead to many promising applications. Herein, we present a reprogrammable 3D chemical shaping strategy for creating a wide variety of stable complex origami and kirigami structures autonomously. This strategy relies on a reverse patterning method that encodes prescribed 3D geometric information as a spatial pattern of the unlocked phase (dispersed phase) in the locked phase …

Graphene-Based Materials Coated On Zeolite For The Removal Of Persistent Organic Pollutants From Water, Yan Zhang

Theses and Dissertations

Adsorption is a fast, low-cost and the most commonly implemented water treatment technology for the removal of multiple contaminations from ground water, drinking water or wastewater. Difficulties in removing persistent organic pollutants (POPs) to improve quality and safety of treated water sources require the exploration of novel and multifunctional materials. Graphene-based materials having unique structures, high specific surface areas and tailorable functional groups are promising candidates as adsorbents.

The main goal of this work is to fabricate a novel adsorbent made of GO/rGO attached on natural zeolite substrates for the removal of variably charged organic model compounds and POPs in …

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 …

Corrosion Of Aluminum Current Collector In Cost Effective Rechargeable Lithium-Ion Batteries, Shengyi Li

Theses and Dissertations

Rechargeable lithium ion batteries (LIB) have been widely used as commercial energy storage systems for portable equipment, electronic devices and high power applications (e.g. electronic vehicles). One issue with the commercialized LIB is that expensive, highly toxic and flammable organic solvents are used in the electrolyte and the fabrication process of electrodes. The toxic organic based solvents increase the production cost and lead to significant safety concerns in the event of a battery overcharge or short circuit. The recent development of “green manufacturing” technology allows manufacturers to replace the organic solvents used in the cathode coating process by aqueous based …

Experimental Methods In Cryogenic Spectroscopy: Stark Effect Measurements In Substituted Myoglobin, Bradley Michael Moran

Theses and Dissertations

Dawning from well-defined tertiary structure, the active regions of enzymatic proteins exist as specifically tailored electrostatic microenvironments capable of facilitating chemical interaction. The specific influence these charge distributions have on ligand binding dynamics, and their impact on specificity, reactivity, and biological functionality, have yet to be fully understood. A quantitative determination of these intrinsic fields would offer insight towards the mechanistic aspects of protein functionality. This work seeks to investigate the internal molecular electric fields that are present at the oxygen binding site of myoglobin.

Experiments are performed at 1 K on samples located within a glassy matrix, using the …

Synthesis And Performance Analysis Of Polyurethane Foam Nanocomposite For Arsenic Removal From Drinking Water, Faten Bakri Hussein

Theses and Dissertations

Water contamination by various heavy metal pollutants such as, Lead, Arsenic, Cadmium, and Mercury, have severe toxic effects on living organisms and humans. High concentrations of arsenic in drinking water cause serious damage to the central and peripheral nervous systems, as well as, the dermal, cardiovascular, gastrointestinal, and respiratory systems. Arsenic contamination of ground water poses a substantial concern in many countries throughout the world, including the United States.

Considerable research work, aimed at finding and developing various separation and treatment techniques, has been conducted over the past few decades. The conventional treatment methods of arsenic involve coagulation with ferric …

Wetting, Superhydrophobicity, And Icephobicity In Biomimetic Composite Materials, Vahid Hejazi

Theses and Dissertations

Recent developments in nano- and bio-technology require new materials. Among these new classes of materials which have emerged in the recent years are biomimetic materials, which mimic structure and properties of materials found in living nature. There are a large number of biological objects including bacteria, animals and plants with properties of interest for engineers. Among these properties is the ability of the lotus leaf and other natural materials to repel water, which has inspired researchers to prepare similar surfaces. The Lotus effect involving roughness-induced superhydrophobicity is a way to design nonwetting, self-cleaning, omniphobic, icephobic, and antifouling surfaces. The range …

Applying Computational Methods To Interpret Experimental Results In Tribology And Enantioselective Catalysis, Michael Garvey

Theses and Dissertations

Computational methods are rapidly becoming a mainstay in the field of chemistry. Advances in computational methods (both theory and implementation), increasing availability of computational resources and the advancement of parallel computing are some of the major forces driving this trend.

It is now possible to perform density functional theory (DFT) calculations with chemical accuracy for model systems that can be interrogated experimentally. This allows computational methods to supplement or complement experimental methods. There are even cases where DFT calculations can give insight into processes and interactions that cannot be interrogated directly by current experimental methods.

This work presents several examples …

An Experimental Investigation Characterizing The Tribological Performance Of Natural And Synthetic Biolubricants Composed Of Carboxylic Acids For Energy Conservation And Sustainability, Carlton Jonathan Reeves

Theses and Dissertations

Over the last several decades the lubrication industry has been striving to bring bio-based lubricants known as biolubricants to prominence. The reasons for the increased environmental initiatives are due to depletion of oil reserves, increases in oil price, stringent government regulations on petroleum-based oils, and most importantly, concerns for protecting the environment. With an estimated, 50% of all lubricants entering the environment and much of these being composed of toxic mineral oils, biolubricants have begun to witness a resurgence. This experimental investigation seeks to develop a new class of ecofriendly biolubricants that are less toxic to the environment, derived from …

Probing Bonding And Dynamics At Heterogeneous Adsorbate/Graphene Interfaces, Eric Charles Mattson

Theses and Dissertations

Graphene-based materials are becoming an astoundingly promising choice for many relevant technological and environmental applications. Deriving graphene from the reduction of graphene oxide (GO) is becoming a popular and inexpensive route toward the synthesis of these materials. While the desired product from GO reduction is pristine graphene, defects and residual oxygen functional groups inherited from the parent GO render reduced graphene oxide (RGO) distinct from graphene. In this work, the structure and bonding for GO and RGO is investigated to the end of a working understanding of the composition and properties of these materials. In situ selected area electron diffraction …

Functional Organic Nanomaterials, Ryan R. Kohlmeyer

Theses and Dissertations

π-Conjugated polymers have a wide range of applications such as photovoltaics, light-emitting diodes, and sensors. To gain a better understanding of these systems, monodisperse oligomers can be used as a more simplistic model to generate predictive structural and physical properties of corresponding polymers. A divergent/convergent synthetic approach to synthesis of monodisperse π-conjugated oligomers has been developed. These well-defined, thiophene-containing molecular building blocks have been successfully coupled to a ferrocene hinge, which has been found to be highly efficient in the transport of gold atoms using a gold scanning tunneling microscopy tip.

Carbon nanotubes (CNTs) represent a rare class of materials, …

Infrared Light Induced Bending Of Liquid Crystalline Elastomer Composite-Silicone Bilayer Films, Maika Moua

Theses and Dissertations

This research centers on infrared (IR) light-induced bending of liquid crystalline elastomers (LCE) composite-silicone bilayer films. Two new developments are presented in this thesis. First, the reversible infrared (IR) induced bending of 0.1% (w/w) single walled nanotube (SWNT)-LCE/silicone bilayer films were successfully prepared and used for fabrication of functioning devices such as folding, grabbing, and crawling structures. Second, the use of adding a filler (absorbs specific wavelength range), such as Dye 1002, into the LCE matrix achieved wavelength selectivity in LCE systems. The 0.2% (wt/wt) Dye 1002-LCE/silicone bilayer films demonstrated bending under a 980 nm laser source but no bending …