To Determine Objectives from the Constitution Preamble, Children's Charter and Social-economic Goals of America, and to Recommend a General Science Curriculum Development to Conform Therto (open access)

To Determine Objectives from the Constitution Preamble, Children's Charter and Social-economic Goals of America, and to Recommend a General Science Curriculum Development to Conform Therto

In this elementary science curriculum development effort, concepts are used as tools in the realization of objectives, but they are not objectives in themselves.
Date: August 1937
Creator: Wilson, Gilbert C.
System: The UNT Digital Library
A Quantitative Study of the Common Metals Found in the Oak and the Pine (open access)

A Quantitative Study of the Common Metals Found in the Oak and the Pine

The purpose of this study is to determine the amounts of the element sulfur, phosphorus, sodium, potassium, silicon, iron, aluminium, calcium, magnessium, and manganess found in the roots, hearts, sap, leaves, and bark of two plants, the short leaf pine and the blackjack oak.
Date: August 1938
Creator: Moore, Carver Yates
System: The UNT Digital Library
Mass Spectrometry Guided Development of a Controlled Release Nanotransfersome Transdermal Drug Delivery System (open access)

Mass Spectrometry Guided Development of a Controlled Release Nanotransfersome Transdermal Drug Delivery System

Poor medical adherence attributed to patient compliance has impacted the medical community, at times, in a deleterious fashion. To combat this, the medical community has attempted to provide therapeutics in the form of absorption enhancing techniques. To improve the absorption rate techniques such as drug encapsulation using proteins, liposomes, or nanotransfersomes have been developed using mass spectrometry. These techniques, have aided in the enhanced absorption of analytes with low bioavailability, including curcumin, simvastatin, and lysozyme. Specifically, mass spectrometry allows for the development and monitoring of nanotransfersome encapsulated analytes and the permeation across the dermal membrane. This transdermal delivery would eliminate the problems encountered during first pass metabolism, while allowing for higher concentrations of analyte to be maintained in the blood serum. This can be coupled to a thermosensitive gelatin that provides for a dose control mechanism to be accomplished, allowing multiple doses to be delivered using one transdermal patch system. The novel delivery system developed using mass spectrometry, allows the analyte to be delivered into the circulatory system at a controlled dosage, via transdermal absorption. This system will aid in eliminating problems associated with patient compliance, as the patient is no longer reliant on memory to self-dose. Further, this system …
Date: December 2020
Creator: Kiselak, Thomas Dieter
System: The UNT Digital Library
Polycyclic Aromatic Hydrocarbons: Spectrofluorometric Quenching and Solubility Behavior (open access)

Polycyclic Aromatic Hydrocarbons: Spectrofluorometric Quenching and Solubility Behavior

Thesis written by a student in the UNT Honors College discussing the removal of toxic polycyclic aromatic hydrocarbons from soil.
Date: Spring 1999
Creator: Roy, Lindsay Elizabeth
System: The UNT Digital Library
Utilizing Rapid Mass Spectrometry Techniques to Profile Illicit Drugs from Start to Finish (open access)

Utilizing Rapid Mass Spectrometry Techniques to Profile Illicit Drugs from Start to Finish

The increasingly complex world of illicit chemistry has created a need for rapid, selective means of determining the threat posed by new drugs as they are encountered by law enforcement personnel. To streamline this process, the entirety of the problem, from the production of illicit drugs all the way to the final analysis have been investigated. A series of N-alkylated phenethylamine analogues were synthesized in a shotgun method and subjected to direct-infusion analysis. A range of products were detected without the need for time-consuming purification steps, which was extended to novel pharmacological and receptor-binding assays where mass spectrometry is used as a detector. This direct-infusion technique was also applied to studies of methamphetamine and fentanyl production to preemptively determine improvements to common reaction conditions and explore the origins of common impurities. The ability to utilize these rapid techniques directly from the fume hood has also been critically reviewed to highlight gaps in current research and opportunities for improvement. When combined, these studies seek to provide a means for rapid, simplified analysis of illicit drugs to improve the quality of data and dramatically increase throughput.
Date: August 2018
Creator: McBride, Ethan
System: The UNT Digital Library

Machine Learning in Computational Chemistry

Machine learning and artificial intelligence are increasingly becoming mainstream in our daily lives, from smart algorithms that recognize us online to cars that can drive themselves. In this defense, the intersection of machine learning and computational chemistry are applied to the generation of new PFAS molecules that are less toxic than those currently used today without sacrificing the unique properties that make them desirable for industrial use. Additionally, machine learning is used to complete the SAMPL6 logP challenge and to correlate molecules to best DFT functionals for enthalpies of formation.
Date: May 2022
Creator: Kuntz, David Micah
System: The UNT Digital Library

Nitrogen Reduction Reaction: Deposition, Characterization and Selectivity of Transition Metal (V, Co and Ti) Oxynitrides as Electrocatalysts

The electrocatalytic nitrogen reduction reaction (NRR) is of considerable interest due to its potential for less energy intensive and environmentally friendly ammonia production which is critical for agricultural and clean energy applications. However, the selectivity of NRR compared to the hydrogen evolution reaction (HER) often poses challenges for various catalysts, including Earth-abundant transition metal oxynitrides like Ti, V, and Co. In this work, a comparative analysis of the selectivity of these three metal oxynitrides was conducted, each having different metal oxophilicities. A combination of electrochemical, surface characterizations and density functional theory (DFT) calculations were employed to directly assess NRR and HER activities under the same reaction conditions. Results show that cobalt oxynitrides exhibit NRR activity at pH 10, involving the electrochemical reduction of both lattice-bound nitrogen and dissolved N2, although more HER activity was observed. In contrast, vanadium oxynitride films displayed HER inactivity at pH 7 and 10 but demonstrated NRR activity at pH 7, while titanium oxynitrides were active at pH 3.2 but inactive under neutral and basic pH conditions. These comprehensive studies highlight substantial variations in HER and NRR selectivity based on transition metal oxophilicity/azaphilicity, indicating distinct mechanisms governing NRR and HER mechanisms.
Date: December 2023
Creator: Chukwunenye, Precious O.
System: The UNT Digital Library
Thermochemical Study of Crystalline Solutes Dissolved in Ternary Hydrogen-Bonding Solvent Mixtures (open access)

Thermochemical Study of Crystalline Solutes Dissolved in Ternary Hydrogen-Bonding Solvent Mixtures

The purpose of this dissertation is to investigate the thermochemical properties of nonelectrolyte solutes dissolved in ternary solvent mixtures, and to develop mathematical expressions for predicting and describing behavior in the solvent mixtures. Forty-five ternary solvent systems were studied containing an ether (Methyl tert-butyl ether, Dibutyl ether, or 1,4-Dioxane), an alcohol (1-Propanol, 2-Propanol, 1-Butanol, 2-Butanol, or 2-Methyl-1-propanol), and an alkane (Cyclohexane, Heptane, or 2,2,4-Trimethylpentane) cosolvents. The Combined NIBS (Nearly Ideal Binary Solvent)/Redlich-Kister equation was used to assess the experimental data. The average percent deviation between predicted and observed values was less than ± 2 per cent error, documenting that this model provides a fairly accurate description of the observed solubility behavior. In addition, Mobile Order theory, the Kretschmer-Wiebe model, and the Mecke-Kempter model were extended to ternary solvent mixtures containing an alcohol (or an alkoxyalcohol) and alkane cosolvents. Expressions derived from Mobile Order theory predicted the experimental mole fraction solubility of anthracene in ternary alcohol + alkane + alkane mixtures to within ± 5.8%, in ternary alcohol + alcohol + alkane mixtures to within ± 4.0%, and in ternary alcohol + alcohol + alcohol mixtures to within ± 3.6%. In comparison, expressions derived from the Kretschmer-Wiebe model and the Mecke-Kempter …
Date: May 2001
Creator: Pribyla, Karen J.
System: The UNT Digital Library