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Articles 1 - 19 of 19
Full-Text Articles in Engineering
Material Development Toward An Index-Matched Gadolinium-Based Heterogenous Capture-Gated Neutron Detector, Aaron J. Thorum
Material Development Toward An Index-Matched Gadolinium-Based Heterogenous Capture-Gated Neutron Detector, Aaron J. Thorum
Theses and Dissertations
Neutron detection is important in several fields, especially detection of illicit nuclear material. Historically, 3He has been the basis for these technologies. Modern realities have necessitated the development of new technologies and the exploration of new materials to meet this need. One potential solution is known as capture-gating, which is a measurement approach that is good at differentiating between incident neutrons and gamma rays. The key issue is that materials used in current capture-gating devices can suffer from poor optical performance. This is due to the fact that the these detectors, whether composed of a heterogeneous or homogeneous mixture of …
Extraction Of Micro- And Nano-Plastic Particles From Water Using Hydrophobic Natural Deep Eutectic Solvents, Jameson R. Hunter
Extraction Of Micro- And Nano-Plastic Particles From Water Using Hydrophobic Natural Deep Eutectic Solvents, Jameson R. Hunter
Theses and Dissertations--Biosystems and Agricultural Engineering
The production of plastic and the amount of waste plastic that enters the environment increases every year. Synthetic polymers will gradually break down into particles on the micro- and nano-scale. The micro- and nano-plastics pose a significant ecological harm by transporting toxic chemicals and causing inflammation and cellular damage when ingested. Two common plastics are polyethylene terephthalate (PET) and Polystyrene (PS), and a newer bioplastic polylactic acid (PLA) that has become a popular alternative. Deep eutectic solvents are a recently discovered solvent composed of a hydrogen bond donor and hydrogen bond acceptor and have been proposed as a cheaper alternative …
Impact Of Chain Architecture On The Thickness Dependence Of Physical Aging Rate Of Thin Polystyrene Films, Gregory Brown, Elizabeth Lewis, Bryan D. Vogt
Impact Of Chain Architecture On The Thickness Dependence Of Physical Aging Rate Of Thin Polystyrene Films, Gregory Brown, Elizabeth Lewis, Bryan D. Vogt
Williams Honors College, Honors Research Projects
The dynamics of polymer thin films have been demonstrated to be significantly altered from the bulk, but the origins of such differences are not well defined. In this work, we seek to understand the differences in the structural dynamics (or physical aging) of polystyrene (PS) through branching and other well defined architectures (comb and centipede). The aging dynamics of ultrathin films (< 30 nm) differ from relatively thick films (100-150nm) with linear PS thin films aging more rapidly than the relatively “bulk-like” thick films. Ellipsometric measurements are used to characterize the physical aging rate of the films. The change in film thickness and refractive index as the films are held below the glass transition temperature (Tg) provides a simple measure of the physical aging. In this study, four different architectures (linear, comb, 4 arm star, and centipede) will be investigated. For each PS architecture, the aging rate will be determined for film …
Towards Completely Automated Glycan Synthesis, Matteo Panza
Towards Completely Automated Glycan Synthesis, Matteo Panza
Dissertations
Carbohydrates are ubiquitous both in nature as biologically active compounds and in medicine as pharmaceuticals. Although there has been continued interest in the synthesis of carbohydrates, chemical methods require specialized knowledge and hence remain cumbersome. The need for development of rapid, efficient and operationally simple procedures has come to the fore. This dissertation focuses on the development of a fully automated platform that will enable both experts and non-specialists to perform the synthesis of glycans. Existing automated methods for the synthesis of oligosaccharides are highly sophisticated, operationally complex, and require significant user know-how. By contrast, high performance liquid chromatography (HPLC) …
Development Of Waste-Based-Thermoplastic Composite Heat Insulators, Waseem Yousef Hittini
Development Of Waste-Based-Thermoplastic Composite Heat Insulators, Waseem Yousef Hittini
Mechanical Engineering Theses
The main scope of this research is to develop polymer-filler thermal insulators utilizing natural and industrial local waste such as date pit powder (DPP), devulcanized tire rubber (DVR), and buffing dust (BD). Recycling and reuse of these local wastes as fillers in insulation materials has significant benefits for the UAE environment. An objective of this work was to study the effect of the combination of these local wastes with polystyrene (PS) on the physical, mechanical, and thermal properties of the developed thermal insulators. PS was used as a matrix, mixed in different proportions with the waste fillers. Each mixture was …
Electrospinning Of Polymeric Solutions Using Opuntia Ficus-Indica Mucilage And Iron Oxide For Nanofiber Membranes For Treating Arsenic Contaminated Water, Venkatesh Eppili
Electrospinning Of Polymeric Solutions Using Opuntia Ficus-Indica Mucilage And Iron Oxide For Nanofiber Membranes For Treating Arsenic Contaminated Water, Venkatesh Eppili
USF Tampa Graduate Theses and Dissertations
Water is the essential part of every organism and it is also a vital constituent of healthy living and diet. Unfortunately water contamination over the past decade has increased dramatically leading to various diseases. As technology advances, we are detecting many pollutants at smaller levels of concentrations. Arsenic (As) is one of those major pollutants, and Arsenic poisoning is a condition caused due to excess levels of arsenic in the body. The main basis for Arsenic poisoning is from ground water which naturally contains high concentrations of arsenic. A case study from 2007 states that over 137 million people in …
Assessing The Performance Of A Soy Methyl Ester -Polystyrene Topical Treatment To Extend The Service Life Of Concrete Structures, D'Shawn G. Thomas
Assessing The Performance Of A Soy Methyl Ester -Polystyrene Topical Treatment To Extend The Service Life Of Concrete Structures, D'Shawn G. Thomas
Open Access Theses
Experimental results show that soy methyl ester (SME), a derivative of soy bean oil, along with the incorporation of polystyrene (PS) is a non-toxic, biodegradable and renewable material that can be used effectively as a topical concrete surface treatment. While, concrete sealants and topical surface treatments can be used to extend to durability of concrete structures, it is difficult to predict the durability of concrete structures sealed with a sealant or topical surface treatment. This is due to a lack of necessary model inputs that can be used to address the durability of concrete structures treated with these materials. In …
Separation Of Water From Ulsd Using Superhydrophobic Ps Nanofiber Mats, Alisa G. Webel
Separation Of Water From Ulsd Using Superhydrophobic Ps Nanofiber Mats, Alisa G. Webel
Williams Honors College, Honors Research Projects
Superhydrophobic polystyrene nanofiber membranes have potential to separate micron scale water droplets from organic due to their hydrophobicity and small pore openings. Polystyrene nanofibers were electrospun into flat sheets and cylindrical filter membranes. The fibers were crosslinked to increase strength and reduce solubility in diesel fuel. The filters were tested and the filtration efficiency was compared to their non-crosslinked counterparts. The optimal electrospinning conditions to create superhydrophobic nanofibers were found to be 20 wt. % PS fibers at 1 mL/hr. under a current of 20kV and at a distance of 20 cm away from the ground. It was found that …
A Computational Study Of The Potential For Lng Tanker Polystyrene Foam Insulation Failure Under Fire Exposure, Jeffrey David Martinez
A Computational Study Of The Potential For Lng Tanker Polystyrene Foam Insulation Failure Under Fire Exposure, Jeffrey David Martinez
Graduate Theses and Dissertations
Liquefied natural gas is shipped across the oceans in large marine carriers. The carriers house the LNG using several different insulation systems. One of these systems involves large aluminum spheres insulated with polystyrene foam. Polystyrene foam is very susceptible to heat degradation. This raised issues as to the extent of possible insulation failure caused by a large ship fire. Experiments were done investigating the nature of polystyrene’s thermal degradation, notably by Brauman, Chen, and Matzinger and Butler. A large scale investigation was also performed by Sandia National Laboratory. However, computational modeling of the degradation was lacking. This work set out …
Characterization Of Plasticizer-Polymer Coatings For The Detection Of Benzene In Water Using Sh-Saw Devices, Jude Coompson
Characterization Of Plasticizer-Polymer Coatings For The Detection Of Benzene In Water Using Sh-Saw Devices, Jude Coompson
Master's Theses (2009 -)
Benzene is a constituent component of crude oil that has been classified as a carcinogen by the EPA with a maximum contamination level (MCL) of 5ppb in drinking water. However, of the aromatic compounds, benzene has one of the lowest polymer-water partition coefficients using commercially available polymers as sensor coatings, resulting in poor limits of detection. This work investigates new coating materials based on polymer/plasticizer mixtures coated onto a shear horizontal surface acoustic wave (SH-SAW) sensor to detect benzene in water. There are many polymers which are unavailable for use as a sensing polymer due to their glassy nature. The …
Investigation Of Opuntia Ficus-Indica Mucilage Nanofiber Membrane Filtration For Water Systems, Rasudha Muppaneni
Investigation Of Opuntia Ficus-Indica Mucilage Nanofiber Membrane Filtration For Water Systems, Rasudha Muppaneni
USF Tampa Graduate Theses and Dissertations
This work investigates the fabrication, characterization and testing of Opuntia ficus-indica mucilage nanofibers to be utilized in water filtration systems. These mucilage nanofibers are formed using different polymers through a process called electrospinning. The polymers used to promote the formation of nanofibers are poly vinyl alcohol (PVA) and polystyrene (PS). The mucilage is a jelly like substance extracted from the pads of the cactus plant. It is a mixture of proteins, complex polysaccharides and monosaccharaides. It is an inexpensive, non-toxic, biodegradable and biocompatible material which is present in abundance. The mucilage extracted from the pads is mixed with acetic acid …
Studies On The Wrinkling Of Thin Polymer Films Floating On Liquid, Kamil B. Toga
Studies On The Wrinkling Of Thin Polymer Films Floating On Liquid, Kamil B. Toga
Doctoral Dissertations
This dissertation aims to broaden our understanding on wrinkling instabilities occurring on floating polymeric sheets, and tries to establish innovative methods that exploit these patterns in studies on material behavior and interfacial phenomena. We will address three major topics in this thesis including, i) characterization of the conditions required to buckle an annular disc, ii) characterization of wrinkles occurring around a droplet/bubble placed on a membrane that is kept taut at the liquid-air interface, and iii) using wrinkling patterns as a probe to understand the interfacial behavior and dynamics of ultrathin films. The first project in this thesis is about …
Bacterial Growth On Metal And Non-Metal Surfaces In A Static Bioreactor, Rolan Yuk Loong Liong
Bacterial Growth On Metal And Non-Metal Surfaces In A Static Bioreactor, Rolan Yuk Loong Liong
Master's Theses
Research was conducted to observe bacterial growth on the surface of metals in a static bioreactor. Metal and non-metal samples were subjected to bacterial exposure (1 day and 9 days). The metal samples were surface treated prior to bacterial exposure. The microstructures of the surface treated samples were analyzed by optical microscopy. After exposure, the microstructures of the samples were analyzed by scanning electron microscopy (SEM). The analysis suggested that microbial attachment on the surface was related to the underlying microstructure of steel. The preferential attachment of microbes could potentially be influenced by cathodic and anodic regions created by the …
Synthesis And Characterization Of Graphene-Polymer Nanocomposites Via Reversible Addition-Fragmentation Chain-Transfer Polymerization, Renpeng Gu
Electronic Thesis and Dissertation Repository
Graphene has emerged as a subject of tremendous scientific interest due to its exceptional electrical, mechanical and thermal properties. When incorporated into a polymer matrix, graphene sheets can significantly improve the properties of the host polymer. However, the dispersion of pure graphene throughout a polymer matrix is not homogeneous, due to the strong van der Waals interactions between graphene sheets and the difference in surface compatabilities. To prevent agglomeration of these graphene sheets, surface functionalization is required. The goal of this thesis was to develop a facile approach for growing polymer chains from the surface of graphene sheets via reversible …
Development Of Magnetic Fabrics With Tunable Hydrophobicity, Thu Ho
Development Of Magnetic Fabrics With Tunable Hydrophobicity, Thu Ho
Theses and Dissertations
Polystyrene (PS) fiber mats incorporating iron (Fe) particles were fabricated by electrospinning and the hydrophobicity of the resulting magnetic fabrics was investigated with and without an applied magnetic field. The results show that the hydrophobicity (as measured using water droplet contact angle) increases in the presence of a magnetic field and the hysterisis in the advancing/receding contact angle (a measure of the stickiness of the surface) decreases in the presence of a magnetic field. It is also shown that the contact angle and hysterises increase with decreasing fiber diameter and mat thickness.
Admicellar Polymerization To Compatibilize Calcium Carbonate With Oil-Based Drilling Mud, Olugbenga Samuel Ojo
Admicellar Polymerization To Compatibilize Calcium Carbonate With Oil-Based Drilling Mud, Olugbenga Samuel Ojo
Electronic Theses and Dissertations
Weighting agents like calcium carbonate (CC) are added to drilling mud to improve mud properties and performance during oil and gas drilling operations. Oil-based mud (OBM), a more preferred drilling mud, being hydrophobic is particularly non-compatible with hydrophilic CC. This work explored an economically viable admicellar polymerization technique to surface-modify the high energy hydrophilic CC surface to a low energy hydrophobic surface by polymerizing organic styrene monomer within an admicelle of nonionic surfactant Triton X-100 adsorbed on the CC surface. BET N2 particle size analysis, Soxhlet extraction of the coated polymer, Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectra analysis, and …
Solid-State Compatibilization Of Immiscible Polymer Blends: Cryogenic Milling And Solid-State Shear Pulverization, Marc Frederick Henry
Solid-State Compatibilization Of Immiscible Polymer Blends: Cryogenic Milling And Solid-State Shear Pulverization, Marc Frederick Henry
Master’s Theses
The blending of common polymers allows for the rapid and facile synthesis of new materials with highly tunable properties at a fraction of the costs of new monomer development and synthesis. Most blends of polymers, however, are completely immiscible and separate into distinct phases with minimal phase interaction, severelydegrading the performance of the material. Cross-phase interactions and property enhancement can be achieved with these blends through reactive processing or compatibilizer addition. A new class of blend compatibilization relies on the mechanochemical reactions between polymer chains via solid-state, high energy processing. Two contrasting mechanochemical processing techniques are explored in this thesis: …
Thermomechanical Characterization Of A Shape Memory Polymer Based Syntactic Foam, Damon Nettles
Thermomechanical Characterization Of A Shape Memory Polymer Based Syntactic Foam, Damon Nettles
LSU Master's Theses
Shape memory polymers (SMPs) are a type of smart material capable of “remembering” multiple shapes and transitioning between them in response to an external stimulus. They offer the potential to self-seal macro-length scale damage in a nearly autonomous fashion. Syntactic foams are lightweight structural materials currently used in the marine and aerospace industries. This study seeks to bring syntactic foams and SMPs together, retaining characteristics of both components, to create a low-density smart composite. The SMP based syntactic foam is used as the core of a grid stiffened sandwich structure capable of healing impact damage multiple times. In order to …
Ethylcellulose Lacquer Coatings For Polystyrene Plastics., Stuart V. Heil
Ethylcellulose Lacquer Coatings For Polystyrene Plastics., Stuart V. Heil
Electronic Theses and Dissertations
An ethylcellulose lacquer system for both decorative and protective purposes was developed for use on polystyrene plastics. It was found that a one-coat lacquer containing only alcohol solvents produced the most satisfactory finish. Formulations were based on experimental work, conducted to determine the effect of the various lacquer components on the plastic. The results of a study of formulations on a two-coat system are presented.