Chemistry 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 …

Piezoelectric Signals In Vascularized Bone Regeneration, Delfo D’Alessandro, Claudio Ricci, Mario Milazzo, Giovanna Strangis, Francesca Forli, Gabriele Buda, Mario Petrini, Stefano Berrettini, M. Jasim Uddin, Serena Danti, Paolo Parchi

Chemistry Faculty Publications and Presentations

The demand for bone substitutes is increasing in Western countries. Bone graft substitutes aim to provide reconstructive surgeons with off-the-shelf alternatives to the natural bone taken from humans or animal species. Under the tissue engineering paradigm, biomaterial scaffolds can be designed by incorporating bone stem cells to decrease the disadvantages of traditional tissue grafts. However, the effective clinical application of tissue-engineered bone is limited by insufficient neovascularization. As bone is a highly vascularized tissue, new strategies to promote both osteogenesis and vasculogenesis within the scaffolds need to be considered for a successful regeneration. It has been demonstrated that bone and …

Synthesis Of Alkylthio Benzene Derivatives Via Simultaneous Diazotization And Nucleophilic Displacement, Abraham Alvarado, Juan D. Deleija, Jose J. Gutierrez

Chemistry Faculty Publications and Presentations

Alkylthio benzene derivatives were effectively synthesized by simultaneous diazotization of aromatic amines and nucleophilic displacement. The method is fairly general and proceeds in moderate yields. Product yields were comparable regardless of steric hindrance of the thiol or of the functional group present in the starting material. The newly developed procedure allowed for the incorporation of a tertiary alkylthio group, which cannot be easily introduced otherwise. The products were characterized by 1H NMR and 13C NMR.

Editorial: Discovery And Development Of Drugs For Neglected Diseases: Chagas Disease, Human African Trypanosomiasis, And Leishmaniasis, Gildardo Rivera, Navin B. Patel, Debasish Bandyopadhyay

Chemistry Faculty Publications and Presentations

Twenty tropical diseases have been listed by the World Health Organization (WHO) as Neglected Tropical Diseases (NTDs). These tropical diseases are called “neglected” for three primary reasons: 1) These diseases are widespread worldwide among the economically weaker (neglected?) section of the society; 2) Although the total number of mortality, morbidity, disability, and health disparity caused annually by the NTDs is more than that attributed by the so-called elite diseases like cancer, diabetes, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), cardio- or neurological diseases but NTD patients do not receive comparable attention or treatment opportunities either from the governments or healthcare professionals …

Benzopyrazine-Based Small Molecule Inhibitors As Trypanocidal And Leishmanicidal Agents: Green Synthesis, In Vitro, And In Silico Evaluations, Jonathan Rock, Daniel Garcia, Omar Espino, Shaila A. Shetu, Manuel J. Chan-Bacab, Rosa Moo-Puc, Navin B. Patel, Gildardo Rivera, Debasish Bandyopadhyay

Chemistry Faculty Publications and Presentations

World Health Organization (WHO) identified twenty tropical disease categories as neglected tropical diseases (NTDs)1. Chagas’ disease (also known as American trypanosomiasis) and leishmaniasis are two major classes of NTDs. The total number of mortality, morbidity, and disability attributed each year due to these two categories of diseases in magnitudes is much higher than the so-called elite diseases like cancer, diabetes, AIDS, cardiovascular and neurodegenerative diseases. Impoverished communities around the world are the major victim of NTDs. The development of new and novel drugs in the battle against Chagas’ disease and leishmaniasis is highly anticipated. An easy and straightforward …

Software For The Frontiers Of Quantum Chemistry: An Overview Of Developments In The Q-Chem 5 Package, Evgeny Epifanovsky, Andrew T. B. Gilbert, Xintian Feng, Joonho Lee, Yuezhi Mao, Shervin Fatehi

Chemistry Faculty Publications and Presentations

This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange–correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods. Methods highlighted in Q-Chem 5 include a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, methods for computing vibronic spectra, the nuclear–electronic orbital method, and …

Molten-Salt-Assisted Annealing For Making Colloidal Znga2o4:Cr Nanocrystals With High Persistent Luminescence, Bhupendra B. Srivastava, Santosh K. Gupta, Swati Mohan, Yuanbing Mao

Chemistry Faculty Publications and Presentations

Persistent luminescent nanocrystals (PLNCs) in the sub-10 nm domain are considered to be the most fascinating inventions in lighting technology owing to their excellent performance in anti-counterfeiting, luminous paints, bioimaging, security applications, etc. Further improvement of persistent luminescence (PersL) intensity and lifetime is needed to achieve the desired success of PLNCs while keeping the uniform sub-10 nm size. In this work, the concept of molten salt confinement to thermally anneal as-synthesized ZnGa2O4:Cr3+ (ZGOC) colloidal NCs (CNCs) in a molten salt medium at 650 °C is introduced. This method led to significantly monodispersed and few agglomerated NCs with a much improved …

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, …

Knn Based Piezo-Triboelectric Lead-Free Hybrid Energy Films, Abu Masa Abdullah, Muhtasim Ul Karim Sadaf, Farzana Tasnim, Horacio Vasquez, Karen Lozano, M. Jasim Uddin

Chemistry Faculty Publications and Presentations

In recent times, the triboelectric and piezoelectric effects have garnered significant attention towards developing advanced material composites for energy harvesting and sensory applications. In this work, potassium sodium niobate (KNN) based energy films (EF) have been developed to utilize mechanical energy while simultaneously taking advantage of triboelectric and piezoelectric mechanisms. The KNN particles were synthesized using a wet ball milling technique and then incorporated into a polyvinylidene difluoride (PVDF) matrix together with addition of multi wall carbon nanotubes (MWCNT). The film was used to develop a piezoelectric nanogenerator (PENG) fitted with copper electrodes. The piezoelectric output of the film was …

Disorder Driven Asymmetry And Singular Red Emission In Doped Lu2hf2o7 Nanocrystals With No Charge Compensating Defects, Santosh K. Gupta, Mitzy A. Penilla Garcia, Jose P. Zuniga, Bhupendra B. Srivastava, Yuanbing Mao

Chemistry Faculty Publications and Presentations

High performance luminescent materials possess low symmetry, high color purity, no charge compensating defects, and high quantum yield. In this work, we have synthesized Lu2Hf2O7 (LuHO) and Lu2Hf2O7:Eu3+ (LuHOE) nanocrystals (NCs) using a molten salt synthesis and confirmed that both are stabilized in defect fluorite structure with a high degree of structural disordering. The LuHO NCs depicted green emission under ultraviolet irradiation, which decreases and increases after being treated in oxidizing and reducing environments, respectively, confirming the role of oxygen vacancies in the emission process. The LuHOE NCs (i) show excitation wavelength-dependent host to dopant energy transfer efficiency, …

Machine Learning Using Host/Guest Energy Histograms To Predict Adsorption In Metal–Organic Frameworks: Application To Short Alkanes And Xe/Kr Mixtures, Zhao Li, Benjamin J. Bucior, Haoyuan Chen, Maciej Haranczyk, J. Ilja Siepmann, Randall Q. Snurr

Chemistry Faculty Publications and Presentations

A machine learning (ML) methodology that uses a histogram of interaction energies has been applied to predict gas adsorption in metal–organic frameworks (MOFs) using results from atomistic grand canonical Monte Carlo (GCMC) simulations as training and test data. In this work, the method is first extended to binary mixtures of spherical species, in particular, Xe and Kr. In addition, it is shown that single-component adsorption of ethane and propane can be predicted in good agreement with GCMC simulation using a histogram of the adsorption energies felt by a methyl probe in conjunction with the random forest ML method. The results …

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 …

Rare Earth Free Bright And Persistent White Light Emitting Zinc Gallo-Germanate Nanosheets: Technological Advancement To Fibers With Enhanced Quantum Efficiency, Bhupendra B. Srivastava, Santosh K. Gupta, Raul Barbosa, Alexa Villarreal, Karen Lozano, Yuanbing Mao

Chemistry Faculty Publications and Presentations

Recent materials science and engineering research focused on defects, dopants, hosts, and morphological structures has resulted in novel cost efficient and sustainable phases with extraordinary properties and performance. Contributing in this direction we have designed dopant and rare earth free white lightemitting zincgallogermanate (ZGG) phosphors in nanosheet (NS) morphology. These ZGG NSs with interlayer and interfacial defects display bright white photoluminescence (PL) with significant quantum yield (QY). Thermal treatment of the as-synthesized ZGG NSs at 750 1C does not degrade their sheet-like morphology while resulting in long persistent luminescence (PerL) with a duration of approximately one hour. Furthermore, to improve …

Chemical Shift Assignments Of The N-Terminal Domain Of Psd95 (Psd95-Nt), Yonghong Zhang, Johannes W. Hell, James B. Ames

Chemistry Faculty Publications and Presentations

Postsynaptic density protein-95 (PSD95) contributes to the postsynaptic architecture of neuronal synapses and plays an important role in controlling synaptic plasticity. The N-terminal domain of PSD95 (residues 1–71, called PSD95-NT) interacts with target proteins (calmodulin, α-actinin-1 and CDKL5), which regulate the Ca2+-dependent degradation of glutamate receptors. We report complete backbone NMR chemical shift assignments of PSD95-NT (BMRB No. 50752).

Polymer Based Triboelectric Nanogenerator For Cost‐Effective Green Energy Generation And Implementation Of Surface‐Charge Engineering, Diana Lopez, Aminur Rashid Chowdhury, Abu Masa Abdullah, Muhtasim Ul Karim Sadaf, Isaac Martinez, Brishty Deb Chowdhury, Serena Danti, Christopher J. Ellison, Karen Lozano, Mohammed Jasim Uddin

Chemistry Faculty Publications and Presentations

Performance of triboelectric nanogenerators for harvesting mechanical energy from the ambient environment has been limited by structural complexity, cost-effectiveness, and mechanical weakness of materials. Herein, a cost-effective vertical contact separation mode triboelectric nanogenerator using polyethylene (PE) and polycarbonate (PC) in a regular digital versatile disc is reported. This cost-effective nanogenerator with simplified structures is able to generate an open-circuit voltage of 215.3 V and short-circuit current of 80 μA. The effects of the distance of impact and the air gap between the triboelectric layers have also been tested from 3 to 9 cm, and 0.25 to 1 cm, respectively. It …