Physical Sciences and Mathematics Commons^™

Microwave Assisted Depolymerization Of Waste Pet Bottles Via Glycolysis, Kingsley Bassey

Theses and Dissertations

One of the most promising and sustainable chemical depolymerization methods for managing the complex environmental problem arising from waste poly(ethylene) terephthalate (PET) bottles is glycolysis. However key challenges such as longer reaction times, complex separation procedures for the depolymerized products, selectivity, thermally stable catalyst need to be addressed.

In this work, we investigated the glycolysis of waste PET under microwave conditions using 1,5,7-Triazabicyclo [4.4.0] dec5-ene (TBD) and 1,8-Diazabicyclo [5.4.0] undec-7-ene (DBU) as catalyst. We evaluated the effect of reaction parameters such as temperature, catalyst concentration and time on PET depolymerization rate (%PET conversion) and product yield. The reaction was conducted …

Electrospun Polyetherimide And Polybenzimidazole Fibers And Composites, Fatema Ha-Mim Binta Hafiz

Theses and Dissertations

In this study, polymer micro- and nanocomposite fibers with PBI and PEI as polymer, and exfoliated graphite and nitroxide-functionalized graphene oxides have been prepared. Electrospinning has been chosen as a fiber processing technique. This work describes the electrospinning process of the mentioned polymer fibers and composite fibers followed by their characterization by XRD, ATR, SEM, TGA, DSC and Tensile testing.

Flexible Quantum Dot Solar Cell With Nanostructure Titanium Dioxide Photoanode With Modified Counter Electrode, Haimanti Majumder

Theses and Dissertations

Because of unique photovoltaic properties, nanostructured morphologies of TiO2 on flexible substrate have been studied widely in recent years in dye-sensitized solar cells (DSSCs). Nanostructured electrode materials with high surface area can promote rapid charge transport and thus improve the light-to-current conversion efficiency. Herein, this project generates an improved photoanode with forest like photoactive TiO2 hierarchical microstructure using a simple and facile hydrothermal route. To improve the photocurrent efficiency, PbS quantum dot has been applied in different thicknesses to evaluate the best performance. The deposition of quantum dot was done by easy SILAR cycle. Four different SILAR cycle has been …

Electrospun Pcl And Pcl/Gel Microfiber Scaffolds As Prototypes For Anterior Cruciate Ligament (Acl) Regeneration And Repair, Diego Rivera

Theses and Dissertations

Polycaprolactone (PCL) is a polymer that has been a focus of tissue engineering due to its range of applicability for biomedical applications. Synthesis of PCL from a microwave-assisted and stannous octoate-catalyzed ring-opening reaction with ε-caprolactone was accomplished. Aligned-fiber microfiber mats were generated via electrospinning for characterization. PCL microfiber mats were characterized via FTIR and scanning electron microscopy. These PCL microfiber mats were mechanically tested to examine their applicability as tools for knee ligament repair. During tensile testing, non-fiber aligned mats lacked the sufficient elastic modulus. Fiber-aligned PCL samples both and gelatin-coated were tested and showed enhanced elastic modulus and extension …

Total Synthesis Of E Stereoisomers Of Bilirubin Oxidation Products, Tess C. Ruiz

Theses and Dissertations

The purpose of the research was to synthesize the E stereoisomer of Bilirubin Oxidation Products that had not been synthesized through a total organic synthesis at the start of this project. There were numerous different procedures for the bromination of citraconic anhydride performed in an attempt to optimize yield and purity. A proposed scheme for the total synthesis of the E isomers was constantly updated and altered while the project was ongoing. The bioactivity of the compounds was to be tested if the project had been finished. This might have contributed to a greater understanding of their function and association …

Microwave Spectroscopy Of Cyclohexanecarboxylic Acid, Chlorosulfonic Acid, And Its Interaction With Water, Diego Erik Rodriguez

Theses and Dissertations

This study combines computational chemistry and microwave spectroscopy to simulate the behavior of two molecules: cyclohexanecarboxylic acid and chlorosulfonic acid. In this thesis, cyclohexanecarboxylic acid will be observed on its own. On the other hand, chlorosulfonic acid will be observed on its own as well as its interaction with one, two, and three water molecules. Chapter 1: Introduction will provide insight on published literature related to cyclohexanecarboxylic acid, chlorosulfonic acid, and perfluoroalkyl substances. Chapter 2: Computational Chemistry will provide the reader with information about the foundation of computational chemistry including theory and development of the science. Chapter 3: Microwave Spectroscopy …

The Impacts And In-Depth Study Of The Environmental Contaminant, Perfluorooctane Sulfonic Acid, And Its Interactions With Water, Karla Veronica Salazar

Theses and Dissertations

Perfluorooctanesulfonic acid (PFOS), similar to perfluorooctanoic acid (PFOA), is a synthetic chemical that has been classified as a persistent organic pollutant (POP) by the Stockholm Convention since 2009. Due to the wide previous usage, high stability, high bio-accumulative, and low degradative properties is the reason that PFOS has been found in several compartments of the environment including ocean water, ground water, air, and sediments. Due to the strong interactions generated by the sulfonic acid end, this compound has a tendency to stay in the environment for long periods of time and has proved to be difficult in the removal from …

An Innovative Triboelectric Stent Sensor: Prospective Cardiovascular Health Monitor Device, Ulises Vidaurri Romero

Theses and Dissertations

Previous research that has focused on TENGs have lacked the proper application of this energy generator. Currently, heart disease remains the leading cause of death in the United States. With increasing demand for self-sustainable medical devices, this nitinol health monitor sensor device (NHMS) integrates the TENG applications with medical applications. The NHMS features memory shape nitinol electrodes that preserves the device structure while using PDMS and PVDF triboelectric effect to measure heart rate, blood pressure, and breathing patterns. Three constant pressures were measured in this study. At a constant pressure of stage 1, the NHMS produces an average AC of …

Nd Doped Zinc Oxide Based Flexible Pvdf Polymer Composite For Energy Harvesting And Sensory Application, Muhtasim Ul Karim Sadaf

Theses and Dissertations

Flexible Piezoelectric devices have garnered a lot of attention for their potential as energy harvesters and transducers. Zinc Oxide particularly has been doped with different metals and has been incorporated in functional polymers in order to produce flexible piezoelectric devices. In this work, a Neodymium doped Zinc Oxide based flexible piezoelectric energy harvester and sensory device has been developed. For that, neodymium doped zinc oxide has been synthesized using wet chemical co-precipitation method and then has been incorporated in Polyvinylidene Difluoride (PVDF) polymer matrix along with Multiwalled Carbon Nanotubes (MWCNT) to produce flexible piezoelectric films. Silver paste was applied on …

Chemical Investigation Of Camu Camu (Myrciaria Dubia) Leaves And Roots, Jorge L. Flores

Theses and Dissertations

Flores, Jorge L., Chemical Investigation of Camu Camu (Myrciaria dubia) Leaves and Roots. Master of Science (MS), December, 2020, 45 pp., 8 Tables, 28 Figures, 21 references, 12 titles.Being the largest on the planet, the Amazon rainforest also has the greatest biodiversity of plant life on earth. In the lowland regions of the Amazon grows the Peruvian camu camu (Myrciaria dubia) plant. A short and shaggy shrub, camu camu produces a tasty but sour fruit. Camu camu’s berry-like fruit is widely consumed by the native people of the Amazon. Its distinguished richness in vitamin C, as …

Applications Of Vanadium Phthalocyanine In Catalytic, Acid-Based Medium To Couple Sugar Molecules, Juan Ricardo Luna

Theses and Dissertations

The vanadium-substituted tetraazatetrabenzoporphyrin, vanadium phthalocyanine, was synthesized via reflux and characterized using FITR and XRD analysis. Subsequent to synthesis, the vanadium phthalocyanine was studied as a catalyst in redox reactions to convert fructose to different molecules, the products were predominately levulinic methyl ester and heptadionic acid. The ability to convert fructose to other compounds, such as alkyl levulinic derivative, is an important process to help eliminate reliance on traditional chemical feed stocks and promote alternative fuels. Levulinic acid has been commonly used as a starting material in the synthesis of biofuels and a precursor for pharmaceuticals, plasticizers, THF derivatives, γ-valerolatone. …

Uptake Analysis Of As(Iii) And As(V) By Cassia Fistula Seedlings, Valeria Velazquez

Theses and Dissertations

The natural and anthropogenic contamination of water by arsenic has become a major concern to the environment and public health. Phytoremediation is an attractive alternative to ecologically friendly remove contaminants at a potential high efficiency and low cost. Absorption of As(III) and As(V) was evaluated by the measuring the content of arsenic in the roots, leaves and stems Cassia fistula grown under controlled conditions in a hydroponics system. After seeds were germinated, the plants were grown in Hoagland nutrient solution individually supplemented with 1, 2, 5 ppm of As(III) and As(V). After two weeks of exposure, samples of leaves, roots, …

Removal Of Arsenic (Iii) And Arsenic (V) From Aqueous Solution Via Solanum Lycopersicum Phytoremediation And Essential Nutrient Analysis, Grecia W. Garcia Salazar

Theses and Dissertations

ICP-OES was used to investigate the uptake of arsenic (V) and arsenic (III) from aqueous solution using tomato seedlings. The effect of arsenic on essential nutrient uptake by tomato was analyzed. The experiment was performed at three levels of arsenic: 1ppm, 2 ppm and 5 ppm [added as sodium arsenate (Na3AsO4) and arsenic trioxide (As2O3)], in nutrient solution. Plants remained in solution for two weeks. Arsenic accumulation depended on arsenic concentration in solution, when exposed to higher arsenic concentrations the plant uptake increased. The highest arsenic accumulation was found in roots, followed by stems and leaves in that order. Essential …

Virtual Screening For Potential New Chemotherapeutic Agents For The Gpr119 Receptor, A Target For Type Ii Diabetes, Jennifer Lizeth Bravo

Theses and Dissertations

Three frames from a molecular dynamics simulation run of a GPR119 receptor homology model were used for this study. The homology model was validated by virtually screening 76 known GPR119 receptor. 85% of these agonists bound to the receptor. Following the validation, 21,000 molecules were selected for the virtual screening study. 862 ligands came from the GPCR Selleckchem/Prestwick library, 42 compounds from the Prestwick Phytochemical library, 20,000 compounds from the ZINC library, plus four molecules from the literature. All ligands were built, geometry-optimized, and docked in the GPR119 models using a protocol combining High Throughput Virtual Screening, Standard Precision, and …

Investigation Of The C—Cn Bond Activation Of Fluorinated Benzonitriles With [Ni(Dmpe)] And Dft Benchmarking Study With [Ni(Dippe)], Dominique C. Gallegos

Theses and Dissertations

Carbon-carbon bond activation has become a rapidly growing area of research due to its extensive range of applications. Despite the significant progress that has been made in this field, the cleavage of kinetically inert and thermodynamically stable C—C σ-bonds under mild homogeneous conditions remains a challenge. The activation is primarily limited to systems in which either relief of strain or aromatization serves as a driving force. A notable exception to this is the oxidative addition of unstrained C—CN bonds of nitriles. In this study, we are looking at the effect of fluoro substituents. We hypothesized …

Limits Of Variationality In Full Configuration Interaction For The H2 Model System, Oscar Obed Rodriguez Vargas

Theses and Dissertations

We proposed a framework for exploring the limits of variationality in full configuration interaction (FCI) calculation of molecular electronic structure. We performed FCI calculations on the minimal basis (STO-3G) H2 model for the energy, gradient, and derivative coupling. These calculations were validated by finite difference. These quantities were recalculated with controlled injection of error in the FCI coefficient. The gradient was observed to be highly sensitive to error, while the energy and derivative coupling were robust to errors in the coefficients of nearly 10%. This study lays the groundwork for calculation of other derived quantities, such as the Hessian, adiabatic …

Flexible And Surface Modified Znsno3 Nanocubes For Enhanced Piezoelectric Power Generation And Wireless Sensory Application, Sk Md Ali Zaker Shawon

Theses and Dissertations

Piezoelectric systems and their mechanisms are held in high regard, due to their cost-effective structure and mechanical proficiency to harvest renewable energy. In the present article, we propose an aluminum-doped zinc stannate (ZnSnO3) piezoelectric nanogenerator that can be employed for the harvest of energy and sensory applications. In order to ensure and further enrich the piezoelectric mechanics and product outcome in our device, ZnSnO3 was doped with 1 wt% to 5 wt% of aluminum nanoparticles. We reported that 2 wt% of aluminum-doped ZnSnO3 showed the highest electrical output in terms of open circuit voltages and short circuit current.

The nanogenerator …

A Study Of Nanogenerator Based Flow Sensor, Farzana Tasnim

Theses and Dissertations

The utilization of kinetic energy from fluid flow to power sensory systems is experiencing an all-time high research focus. Invention of nanogenerators have fueled this research focus with unprecedented flexibility of applications. Many studies have reported on utilizing the mechanism of nanogenerator for sensing fluid flow. In this short work, we have summarized different types of self-powered nanogenerator-based flow sensors and their applications. We have also classified the use of Nanogenerator based flow sensors in different fields, such as Bio-medical Application, Fluid velocity sensing, and Chemical Detection. In the Bio-medical field, the flow sensor can be used for the patient’s …