Engineering Commons^™

Developing A Risk Assessment Protocol To Quantify Distribution And Uptake Of Persistent Organic Pollutants In Glacial Outflows, Kimberley Rain Miner

Electronic Theses and Dissertations

Pollutants released by industrialized nations between 1960 and 2004 have been transported northward through atmospheric processes and deposited into glaciated alpine ecosystems. Many of these chemicals retain their original structure and are absorbed into the biota thousands of miles away from where they were originally utilized. With a warming climate increasing the melt of alpine glaciers, these glaciers may be introducing growing amounts of toxins into the watershed. While studies have demonstrated the existence of resident pollutants within glaciated ecosystems, no one has developed a risk assessment to identify sources and quantity of risk posed by these compounds when released …

Nmr Studies Of Loaded Microspheres, Ming Huang, Sisi Chen, Rex E. Gerald Ii, Jie Huang, Klaus Woelk

Electrical and Computer Engineering Faculty Research & Creative Works

Porous-wall hollow glass microspheres (PWHGMs) are a novel form of glass materials that consist of 1-μm-thick porous silica shells, 20-100 μm in diameter, with a hollow cavity in the center. Utilizing the central cavity for material storage and the porous walls for controlled release is a unique combination that renders PWHGMs a superior vehicle for targeted drug delivery. In this study, NMR spectroscopy was used to characterize PWHGMs for the first time. A vacuum-based loading system was developed to load PWHGMs with various compounds followed by a washing procedure that uses solvents immiscible with the target material. Immiscible binary model …

Biocompatible, Responsive Polysoaps Via Raft Copolymerization For The Delivery Of Model Cancer Therapeutics, Mason Dearborn

Honors Theses

Many chemotherapeutic drugs are small, hydrophobic molecules that require water-soluble, biocompatible nanocarriers for enhanced vascular circulation. Existing polymeric carriers either conjugate the drug along a copolymer backbone or sequester drugs within a protected interior domain to be delivered to specific sites in the body. Such therapeutic systems must overcome a myriad of hurdles, beginning with complex, multi-step syntheses, followed by other inherent barriers that limit the efficiency of drug delivery at the targeted site. This work aims to circumvent a number of these issues using biocompatible, stimuli-responsive polysoaps that are capable of unimeric micelle formation, hydrophobic drug delivery, and triggered …

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 …

Development Of Microdialysis Probes In Series Approach Toward Eliminating Microdialysis Sampling Calibration: Miniaturization Into A Pdms Microfluidic Device, Randy Espinal Cabrera

Graduate Theses and Dissertations

A new microdialysis sampling method and microfluidic device were developed in vitro. The method consisted of using up to four microdialysis sampling probes connected in series to evaluate the relative recovery (RR) of different model solutes methyl orange, fluorescein isothiocyanate (FITC)-dextran average mol. wt. 4,000 (FITC-4), FITC-10, FITC-20, and FITC-40. Different flow rates (0.8, 1.0, and 1.5 µL/min) were used to compare experimentally observed relative recoveries with theoretical estimations. With increasing the number of probes in series, the relative recovery increases and ~100% (99.7% ± 0.9%) relative recovery for methyl orange was obtained. For larger molecules such as fluorescein isothiocyanate …

Surface Reaction And Diffusion Kinetics In Semiconducting Metal Oxide Film Gas Sensors, Aravind Reghu

Electronic Theses and Dissertations

Chemiresistive metal oxide gas sensors based on materials such as SnO₂, ZnO, and TiO₂, have been investigated extensively by many researchers for a wide range of applications. The band bending model, based on the surface chemistry of highly reactive ionosorbed species (O₂^- or O^-) and the semiconducting material properties of SnO₂, TiO₂ and ZnO, adequately predicts the dependence of the change in sensor conductivity (Δσ) as a function of target gas pressure and temperature. However, the band bending model is not applicable to gas sensors based on reducible oxides …

Lithium And The Foreseeable Future, Paolo Vargas

Mechanical Engineering Undergraduate Honors Theses

This paper aims to clarify the uncertainties regarding worldwide lithium resource availability in the years to come. Previous studies made on the subject are presented with some ambiguity and this work intends to fill the gaps. The information and data presented throughout this script with respect to global lithium resources and reserves are mostly based on data released by the United States Geological Survey (USGS). Lithium resource availability in the future is a point of paramount significance primarily for the automotive, portable electronics, and the power generation industry. Since, a change of supply would ultimately affect the price of lithium, …

Polymer Nanocomposites Containing High Aspect Ratio Particulates: Innovation In Co-Extruded Multilayer Barrier Films, Kevin Meyers

Dissertations

Delaminated montmorillonite (MMT) clay/ maleic anhydride grafted LLDPE nanocomposite multilayer films with alternating layers of LDPE were produced through multilayer co-extrusion. The MMT concentration within the nanocomposite layers was increased through annealing the films in the melt due to a mismatch in interdiffusion rates of the polymer layers. Analysis of the nanocomposite layers upon annealing revealed that the platelets impinged upon one another resulting in significant improvement in oxygen barrier in the multilayer system, exceeding the results of bulk nanocomposites.

Model analysis demonstrated that increasing the nanoplatelet aspect ratio or initial concentration in the filled layers would lead to even …

Highly Flame Retardant And Bio-Based Rigid Polyurethane Foams Derived From Orange Peel Oil, Chunyang Zhang

Electronic Theses & Dissertations

Polyurethane is an important class of polymer which is being used for various industrial applications in the form of rigid foams, flexible foams, thermoplastic, elastomer, coating, and adhesive. Especially there is a huge market for rigid polyurethane foams for their applications as thermal insulating material in building and housing. In general, polyurethanes are prepared using polyols and diisocyanates. Most of the polyols used by industries are petrochemical based. In this project, a novel polyol from an orange peel oil-based derivative, limonene dimercaptan, was synthesized using one step photochemical thiol-ene reaction. The synthesized polyol was used to prepare flame retardant polyurethane …

Preparation Of Ni(Dpim)2Cl2 Complex For The Electrocatalytic Reduction Of Co2, Li-Pu Zhang, Dong-Fang Niu, Xin-Sheng Zhang

Journal of Electrochemistry

A new Ni(dpim)₂Cl₂complex using 2-(diphenylphosphino)-1-methylimidazole (dpim) as ligand was prepared and served as a catalyst for the electrochemical reduction of CO₂. The electrochemical redox behavior of Ni(dpim)₂Cl₂ in CH₃CN/TPABF₄ solution under nitrogen atmosphere showed the two-electron irreversible reduction at -0.7 V and one-electron quasi-reversible reduction at -1.3 V. After bubbling CO₂ into the electrolyte, the reduction peak appeared at -1.3 V became irreversible and the peak current increased from 0.48 mA·cm^-2 to 0.55 mA·cm^-2. Moreover, the peak current at -1.3 V could further increase …

Interaction Between Energy And Electrocatalysis—A Review On The 1st Young Scientist Forum On Energy Electrocatalysis, Hong Li, Wen-Bin Cai

Journal of Electrochemistry

No abstract provided.

Electrochemical Oxidation Of P-Chlorophenol On Porous Ti/Bdd Electrode Cooperated With Cathode Dechlorination, Rong-Ling Chen, Wei-Min Huang, Ya-Peng He, Jun Shi, Hai-Bo Lin

Journal of Electrochemistry

The electrochemical oxidation of p-chlorophenol on porous Ti/BDD electrode cooperated with synergistic effect of cathode dechlorination was studied. Electrochemical degradation tests of p-chlorophenol were conducted in single and double compartment electrolytic cells separately, and the results showed that the mineralization happened mainly in the anode region. The product of chloride ions produced from the cathodic reduction of 4-chlorophenol in the single cell migrated to the anode region and further generated active chlorine toward electro-catalytic oxidation. At the same time, the chloride ion produced from the cathode of the double cell was difficult to be migrated to the anode …

Preparation Of Co3O4/Ti Electrocatalytic Membrane Electrode For Catalytic Oxidation Of Benzyl Alcohol, Yu-Mei Zheng, Zhen Yin, Hong Wang, Jian-Xin Li

Journal of Electrochemistry

The cobalt oxide(Co₃O₄) nanoparticles were loaded on microporous Ti membrane to prepare Co₃O₄/Ti electrocatalytic membrane electrode by dip-coating method. The microstructures and electrochemical properties of Co₃O₄/Ti electrocatalytic membrane were investigated. The Co₃O₄/Ti electrocatalytic membrane reactor (ECMR) assembled by using the Co₃O₄/Ti electrocatalytic membrane as an anode was adopted for catalytic oxidation of benzyl alcohol to produce benzaldehyde and benzoic acid.The effects of different operation parameters on benzyl alcohol conversion, and selectivity to benzaldehyde and benzoic acid of ECMR were studied. …

Effects Of Rotating Magnetic Fields On Pem Fuel Cell Performance, Mao-Liang Wu, En-Ze Wang, Guang-De Pan, Zhong-Jun Liu, Fei Xie

Journal of Electrochemistry

Proton Exchange Membrane (PEM) fuel cell performance may be improved by application of additional magnetic fields. In this work, one square permanent magnet, made of either 16 combination cylinder magnets with homopolarity or 16 combination cylinder magnets with heteropolarity, was exerted on the fuel cell surface to produce additional magnetic field affecting PEM fuel cell performance. The influences of magnetic field status (rotating, static and none) on polarization and power density curves measured in a PEM fuel cell were investigated. The results verified the benefit of magnetic field, proving that the magnetic field distribution could improve the fuel cell output. …

Preparation And Properties Of Manganese Oxide And Polyaniline-Carbon Composite Electrode, Tian-Tian Zhou, Bing Wu, Chao Deng, Ying Gao

Journal of Electrochemistry

The polyaniline-carbon (PAnC) electrode was prepared by the polymerization of aniline monomer and activated carbon in ice water bath, and followed by chemical deposition of manganese dioxide MnO₂-PAnC composite material. The specific capacitance of MnO₂-PAnC reached 459 F•g^-1. The cyclic voltammetric results showed a small deformation in the voltammogram curve obtained with the MnO₂-PAnC electrode at high scan rate, indicating good reversibility and capacitive properties. The AC impedance results revealed that the MnO₂-PAnC electrode displayed the smallest charge transfer resistance and the fastest diffusion
rate of surface ions than other …

Electrochemical Performance Of Moo2-C Composite Coatings, Quan-Yi Li, Qi Yang, Yan-Hong Zhao

Journal of Electrochemistry

The molybdenum dioxide-carbon(MoO₂-C)composite coatings on the surface of Cu foils were prepared by simple knife coating route and followed by sintering in vacuum. The morphology, composition, structure and electrochemical performance of the MoO₂-C composite coatings were investigated. The results demonstrated that the MoO₂-C composite coatings consist of MoO₂ nano-particles with monoclinic crystal structure and amorphous carbon. Some MoO₂ nano-particles with a size range of 5-30nm were loaded on the surface of carbon matrices; while some MoO₂ nano-particles with a size of ~5nm were encapsulated inside. The composite coatings showed porous structure …

Preparations And Corrosion Protection Investigations Of Diethylene Triamine Penta(Methylene Phosphonic Acid)-Zn2+ Conversion Coatings On Cold Rolled Steel Substrates, Wei He, Ru Yan, Ying-Qi Wang, Xiang Gao, Hou-Yi Ma

Journal of Electrochemistry

Novel diethylene triamine penta(methylene phosphonic acid) (DTPMPA)-zinc ion (Zn²⁺) conversion coatings with uniform blue color and excellent corrosion protection were directly formed on the cold rolled steel (CRS) substrates by immersing a CRS plate into the film-forming solutions containing the appropriate concentrations of DTPMPA and Zn²⁺ ion at the proper pH. In this paper, surface morphologies and elemental compositions of DTPMPA-Zn²⁺ conversion coatings were characterized by SEM and EDS, respectivey. The surface functional groups, chemical constituents and binding modes to the substrates were investigated by means of FTIR and XPS methods. The influences of DTPMPA concentrations …

Synthesis And Electrochemical Properties Of Li3V2(Bo3)3/C Anode Materials For Lithium-Ion Batteries, You Wang, Yi-Wen Zeng, Xing Zhong, Xing Liu, Quan Tang

Journal of Electrochemistry

The Li₃V₂(BO₃)₃/C (LVB/C) composite materials were successfully synthesized in two steps：Firstly, a stoichiomertric mixture of Li₂C₂O₄, V₂O₅, H₃BO₃, H₂C₂O₄•H₂O and ethanol was thoroughly ball-milled to get the precursors. Secondly, the precursors were post-calcinated to get the ultimate products. The calcination temperatures of 750 ℃, 800 ℃ and 850 ℃ were selected based on TG-DTA analyses. The crystal structures, surface morphologies and carbon contents of the samples calcinated at five conditions, …

Simulation Analysis In Dynamic Performance Of Proton Exchange Membrane Fuel Cell Under Starting Condition, Yan Xiao, Ying-Jie Chang, Wei Zhang, Qiu-Hong Jia

Journal of Electrochemistry

Based on the equivalent circuit model, by considering both the dynamic gas pressure model and the dynamic heat transfer model, a lumped parameter model is developed. The start process of the fuel cell is simulated by using SIMULINK software. The undershoot of the voltage is observed from the simulation results, and the response time of the voltage is basically the same as that of the fuel cell temperature, which indicates that the temperature has great influence on the dynamic performance of the fuel cell. From the perspective of the temperature, the dynamic responses of the thermodynamic potential, the activation overvoltage, …

Developing Kenya’S Educational Capacity In Nuclear Security Through Nuclear Forensics Research, Hudson Kalambuka Angeyo

International Journal of Nuclear Security

Nuclear energy’s distinctive characteristics give rise to special educational requirements. These requirements are necessary to not only address the danger of nuclear proliferation, but also to build capacity for a secure nuclear fuel circle. In this paper, I assess the status of educational capacity in nuclear security both in response to, and in support of, Kenya’s nuclear power program. I highlight the nuclear security educational infrastructure’s key features in the context of nuclear power, noting the low capacity at Kenyan universities. I identify the steps required to ensure that the country’s dynamic nuclear regulatory infrastructural framework is used effectively to …

From Flasks To Applications: Design And Optimization Of Giant Quantum Dots Using Traditional And Automated Synthetic Methods, Christina J. Hanson

Nanoscience and Microsystems ETDs

Semiconducting nanocrystals, also known as quantum dots (QDs), that emit light with near-unity quantum yield and are extremely photostable are attractive options as down-conversion and direct electricity-to-light materials for a variety of applications including solid-state lighting, display technologies, bio-imaging and optical tracking. Standard QDs with a core/thin shell structure display fluorescence intermittency (blinking) and photobleaching when exposed to prolonged room temperature excitation for single dot measurements, as well as significant reabsorption and energy transfer when densely packed into polymers or at high solution concentrations.

We have developed thick shell “giant” QDs (gQDs), ultra-stable photon sources both at the ensemble and …

Variable Temperature Thermochromic Switching Under Varying Illumination, Alexis Corbett, Danielle Hall, John E. Sinko

Huskies Showcase

Award for "Runner-Up Poster Presentation".

Abstract

Minnesota is home to some of the greatest temperature ranges in the United States, with lows reaching below -40º Celsius and highs reaching nearly 40ºC. This results in higher than average spending on the heating and cooling of buildings. We have been investigating into responsive building materials to help address this. In particular, we have been studying a thermochromic paint that can capture solar energy and transfer it into the building as heat at low temperatures and reflect the energy at higher temperatures to keep the building cooler.

Elastin-Like Polypeptide Fusion Tag As A Protein-Dependent Solubility Enhancer Of Cysteine-Knot Growth Factors, Tamina L. Johnson

USF Tampa Graduate Theses and Dissertations

Elastin-like peptide (ELP) fusions promote therapeutic delivery and efficacy. Recombinant proteins, like neurotrophins, lack bioavailability, have short in vivo half-lives, and require high manufacturing costs. Fusing recombinant proteins with genetically encodable ELPs will increase bioavailability, enhance in vivo solubilization, as well as provide a cost-effective method for purification without the need for chromatography. During expression of neurotrophin-ELP (N-ELP) fusions, dense water-insoluble aggregates known as inclusion bodies (IBs) are formed. Inclusion bodies are partially and misfolded proteins that usually require denaturants like Urea for solubilization. Strong denaturants arrest ELPs stimuli-responsive property and increase unwanted aggregation, making purification difficult, yet possible. The …

Metabolism-Driven High-Throughput Cancer Identification With Glut5-Specific Molecular Probes, Srinivas Kannan, Vagarshak Begoyan, Joseph Fedie, Shuai Xia, Łukasz J. Weseliński, Marina Tanasova, Smitha Rao

Michigan Tech Publications

Point-of-care applications rely on biomedical sensors to enable rapid detection with high sensitivity and selectivity. Despite advances in sensor development, there are challenges in cancer diagnostics. Detection of biomarkers, cell receptors, circulating tumor cells, gene identification, and fluorescent tagging are time-consuming due to the sample preparation and response time involved. Here, we present a novel approach to target the enhanced metabolism in breast cancers for rapid detection using fluorescent imaging. Fluorescent analogs of fructose target the fructose-specific transporter GLUT5 in breast cancers and have limited to no response from normal cells. These analogs demonstrate a marked difference in adenocarcinoma and …

3d Printable Optomechanical Cage System With Enclosure, Brandon Winters, David Shepler

Chemistry Faculty Publications

The advent of the computer-age in the mid to late 20th century brought the development of sophisticated scientific equipment for myriad chemical analyses. The field of spectroscopy alone has seen significant advances in data collection, processing, and analysis due principally to the incorporation of microprocessors. While it is clear computers have revolutionized the field of instrumental chemical analysis their impact is pervasive through every segment of our lives. From word processing, data management, and Computer Aided Design in our work environments to social media, crowd funding, and digital news at home, technology is everywhere. This work seeks to incorporate the …

Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein, Pegah Kord Forooshani, Bruce P. Lee

Bruce Lee

Marine mussels secret protein-based adhesives, which enable them to anchor to various surfaces in a saline, intertidal zone. Mussel foot proteins (Mfps) contain a large abundance of a unique, catecholic amino acid, Dopa, in their protein sequences. Catechol offers robust and durable adhe-sion to various substrate surfaces and contributes to the curing of the adhesive plaques. In this article, we review the unique features and the key functionalities of Mfps, catechol chemistry, and strategies for preparing catechol-functionalized poly- mers. Specifically, we reviewed recent findings on the contributions of various features of Mfps on interfacial binding, which include coacervate formation, surface …

Functionalized Nanoporous Carbon Scaffolds For Hydrogen Storage Applications, Christopher Carr

Dissertations

Recent efforts have demonstrated confinement in porous scaffolds at the nanoscale can alter the hydrogen sorption properties of metal hydrides, though not to an extent feasible for use in onboard hydrogen storage applications, proposing the need for a method allowing further modifications. The work presented here explores how the functionalization of nanoporous carbon scaffold surfaces with heteroatoms can modify the hydrogen sorption properties of confined metal hydrides in relation to non-functionalized scaffolds (FS). Investigations of nanoconfined LiBH₄and NaAlH₄indicate functionalizing the carbon scaffold surface with nitrogen can shift the activation energy of hydrogen desorption in excess of …

Dynamics Of Singlet Fission And Electron Injection In Self-Assembled Acene Monolayers On Titanium Dioxide, Natalie A. Pace, Dylan H. Arias, Devin B. Granger, Steven Christensen, John E. Anthony, Justin C. Johnson

Chemistry Faculty Publications

We employ a combination of linear spectroscopy, electrochemistry, and transient absorption spectroscopy to characterize the interplay between electron transfer and singlet fission dynamics in polyacene-based dyes attached to nanostructured TiO₂. For triisopropyl silylethynyl (TIPS)-pentacene, we find that the singlet fission time constant increases to 6.5 ps on a nanostructured TiO₂ surface relative to a thin film time constant of 150 fs, and that triplets do not dissociate after they are formed. In contrast, TIPS-tetracene singlets quickly dissociate in 2 ps at the molecule/TiO₂ interface, and this dissociation outcompetes the relatively slow singlet fission process. The addition …

Preparation, Modification, Characterization, And Biosensing Application Of Nanoporous Gold Using Electrochemical Techniques, Jay Bhattarai, Dharmendra Neupane, Bishal Nepal, Vasilii Mikhaylov, Alexei Demchenko, Keith Stine

Chemistry & Biochemistry Faculty Works

Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning …

Preparation, Modification, Characterization, And Biosensing Application Of Nanoporous Gold Using Electrochemical Techniques, Jay Bhattarai, Dharmendra Neupane, Bishal Nepal, Vasilii Mikhaylov, Alexei Demchenko, Keith Stine

Alexei Demchenko