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open access

The performance of density functional theory with the correlation consistent basis sets.

Description: Density functional theory has been used in combination with the correlation consistent and polarization consistent basis sets to investigate the structures and energetics for a series of first-row closed shell and several second-row molecules of potential importance in atmospheric chemistry. The impact of basis set choice upon molecular description has been examined, and irregular convergence of molecular properties with respect to increasing basis set size for several functionals and molecules… more
Date: August 2005
Creator: Wang, Xuelin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Allowing Students to Have VOICES (Voluntary Options in Chemical Education Schedules) in General Chemistry I

Description: The purpose of this investigation (a quasi-experimental design called a non-equivalent design group (NEDG)) was to determine if allowing students in a science majors general Chemistry I course the choice in establishing the due dates that their homework was due to the instructor would improve course averages. This study covered two semesters with a total of 288 students participating with n = 158 in the fall and n = 130 in the spring. The students self-selected the homework group, VOICES, tha… more
Date: December 2018
Creator: Ford, Robyn Lynn
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Effects of Web-based Instruction in High School Chemistry.

Description: The intent of this study is to identify correlations that might exist between Web-based instruction and higher assessment scores in secondary education. The study framework was held within the confines of a public high school chemistry classroom. Within this population there were students identified as gifted and talented (GT) as well as those without this designation. These two classifications were examined for statistically higher assessment scores using a two-tailed t-test. Results indicated… more
Access: Restricted to the UNT Community Members at a UNT Libraries Location.
Date: May 2003
Creator: Stratton, Eric W.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

General Chemistry Topic Coverage (GCTC) comparison between community colleges and universities in the United States.

Description: This study is based on survey responses of 224 general chemistry instructors at United States (U.S.) community colleges and universities representing 46 states. The mean values of General Chemistry Topic Coverage (GCTC) score, developed by this researcher specifically for this dissertation study as a measure of course content, were statistically analyzed. The aim of this study is to answer five research questions: (a) Is there a difference in mean GCTC scores between U.S. community colleges and… more
Date: December 2006
Creator: El-Ashmawy, Amina Khalifa
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Comparison of Homework Systems (Four Web-Based) used in First-Semester General Chemistry

Description: Web-based homework systems are becoming more common in general chemistry as instructors face ever-increasing enrollment. Yet providing meaningful feedback on assignments remains of the utmost importance. Chemistry instructors consider completion of homework integral to students' success in chemistry, yet only a few studies have compared the use of Web-based systems to the traditional paper-and-pencil homework within general chemistry. This study compares the traditional homework system to four … more
Date: May 2009
Creator: Belland, Joshua
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Teaching First-Semester General Chemistry Using 3D Video Games following an Atoms First Approach to Chemistry

Description: The unified learning model (ULM) focuses on students' engagement, motivation, prior knowledge, and working memory. This study employs the use of video games to assess students' learning through a 3D chemistry gaming environment. In this human-subjects research, students carried out missions and applied reasoning to solve problems appropriate for general chemistry content. For learning to occur, students must be engaged and motivated as stated in the ULM. Learning cannot necessarily be accomplis… more
Date: August 2018
Creator: Jenkins, Dave A
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Machine Learning in Computational Chemistry

Description: 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 t… more
This item is restricted from view until June 1, 2024.
Date: May 2022
Creator: Kuntz, David Micah
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

The Development of the Attitudes Towards Organic Chemistry Instrument

Description: In this study, undergraduate student attitudes towards organic chemistry and the influences that shape those attitudes were explored using the Attitudes Towards Organic Chemistry Instrument (ATOC) to collect both qualitative and quantitative data. The findings from the qualitative ATOC items provide evidence that students displayed a wide range of attitudes towards organic chemistry, including positive, negative, neutral, and blended attitudes. Five major influences were shown to have shaped th… more
This item is restricted from view until September 1, 2024.
Date: August 2022
Creator: Collini, Melissa Anne
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Comparison of the Achievements of Science and Non-Science Majors Enrolled in General Chemistry at North Texas State College

Description: It is the specific purpose of this investigation to determine the difference, if any, in the amount of practical, everyday chemistry learned by the science majors as opposed to the non-science majors enrolled in general chemistry at the North Texas State College during the school year 1950-1951.
Date: 1951
Creator: Brogdon, Billie R.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Interaction of learning approach with concept integration and achievement in a large guided inquiry organic class.

Description: A study was conducted to investigate the relationship of students' concept integration and achievement with time spent within a topic and across related topics in a large first semester guided inquiry organic chemistry class. Achievement was based on evidence of algorithmic problem solving; and concept integration was based on demonstrated performance explaining, applying, and relating concepts to each other. Twelve individual assessments were made of both variables over three related topics - … more
Date: August 2009
Creator: Mewhinney, Christina
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Molecular Dynamics in the Liquid Phase by FT-NMR, FT-IR and Laser Raman Lineshape Analysis

Description: Nuclear magnetic resonance (NMR) provides a convenient probe for the study of molecular reorientation in liquids because nuclear spin-lattice relaxation times are dependent upon the details of molecular motion. The combined application of Raman and Infrared (IR) lineshape analysis can furnish more complete information to characterize the anisotropic rotation of molecules. Presented here are the studies of NMR relaxation times, together with Raman/IR Mneshape analysis of the solvent and temperat… more
Date: August 1988
Creator: Chen, Fu-Tseng Andy
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

FT-NMR and Raman Spectroscopic Studies of Molecular Dynamics in Liquids

Description: NMR relaxation and Raman lineshape analysis are well known methods for the study of molecular reorientational dynamics in liquids. The combination of these two methods provides another approach to tackle the characterization of molecular dynamics in liquids. Investigations presented here include (1) NMR relaxation study of polycyclic compounds in solution, (2) the study of nitromethane reorientational dynamics using the NMR and Raman methods, and (3) Raman lineshape analysis of reorientation he… more
Date: December 1993
Creator: Wang, Kuen-Shian
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Investigating Molecular Structures: Rapidly Examining Molecular Fingerprints Through Fast Passage Broadband Fourier Transform Microwave Spectroscopy

Description: Microwave spectroscopy is a gas phase technique typically geared toward measuring the rotational transitions of Molecules. The information contained in this type of spectroscopy pertains to a molecules structure, both geometric and electronic, which give insight into a molecule's chemistry. Typically this type of spectroscopy is high resolution, but narrowband ≤1 MHz in frequency. This is achieved by tuning a cavity, exciting a molecule with electromagnetic radiation in the microwave region, tu… more
Date: May 2011
Creator: Grubbs, Garry Smith, II
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Development of Predictive Models for the Acid Degradation of Chrysotile Asbestos

Description: The purpose of this study was to determine the factors affecting the acid degradation of chrysotile asbestos (Mg_3Si_2O_5(OH_4)) . Millions of tons of asbestos have found use in this country as insulative or ablative material. More than 95 percent of the asbestos in use is of the chrysotile variety. The remaining 5 percent is composed of various types of fibrous amphiboles. The inhalation of asbestos can lead to several diseases in humans. Asbestosis, lung cancer and mesothelioma are the most c… more
Date: May 1993
Creator: Ingram, Kevin D. (Kevin Dean)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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

Description: 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.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Kinetic Studies and Vibrational Spectra of Disubstituted Metal Carbonyls

Description: The oxidative elimination reactions of (5-X-phen)Mo(C0)₄ (X = H, CH₃, Cl, NO₂; phen = o-phenanthroline) and (3,4,7,8-(CH₃)₄-phen)Mo(CO)₄ with mercuric chloride in acetone have been investigated. In these reactions, a carbon monoxide group is replaced by two univalent ligands, accompanied by the corresponding increase in coordination number and formal oxidation state of the central metal atom, to give products of the type, (X-phen)Mo(CO)₃(Cl)HgCl. With the exception of (3,4,7,8-(CH₃)₄-phen), the… more
Date: May 1972
Creator: Jernigan, Robert Thorne
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Comparative Study of Errors in Chemistry and English Found in Examination Papers of Freshman Chemistry

Description: This study attempts to discover what types of errors are commonly made by students in freshman chemistry classes. It considers the errors resulting from the students' lack of knowledge of the subject taught, and errors attributed to their failure to use correct English in their expression of ideas.
Date: August 1938
Creator: Phillips, Annie
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Reducing the Computational Cost of Ab Initio Methods

Description: In recent years, advances in computer technology combined with new ab initio computational methods have allowed for dramatic improvement in the prediction of energetic properties. Unfortunately, even with these advances, the extensive computational cost, in terms of computer time, memory, and disk space of the sophisticated methods required to achieve chemical accuracy - defined as 1 kcal/mol from reliable experimental data effectively - limits the size of molecules [i.e. less than 10-15 non-h… more
Date: August 2008
Creator: Mintz, Benjamin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Instrumental Development and Implementation of Portable Membrane Inlet Mass Spectrometry for Homeland Security and Environmental Applications

Description: A rapidly growing topic of great interest is the adaptation of benchtop analytical instrumentation for use in outdoor harsh environments. Some of the areas that stand to benefit from field instrumentation development include government agencies involved with the preservation of the environment and institutions responsible for the safety of the general public. Detection systems are at the forefront of the miniaturization movement as the interest in analyte identification and quantitation appears… more
Date: December 2021
Creator: Anguiano Virgen, Camila
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Atomic Layer Deposition of Boron Oxide and Boron Nitride for Ultrashallow Doping and Capping Applications

Description: The deposition of boron oxide (B₂O₃) films on silicon substrates is of significant interest in microelectronics for ultrashallow doping applications. However, thickness control and conformality of such films has been an issue in high aspect ratio 3D structures which have long replaced traditional planar transistor architectures. B₂O₃ films are also unstable in atmosphere, requiring a suitable capping barrier for passivation. The growth of continuous, stoichiometric B₂O₃ and boron nitride (BN) f… more
Date: December 2020
Creator: Pilli, Aparna
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Chemical Equilibria in Binary Solvents

Description: Dissertation research involves development of Mobile Order Theory thermodynamic models to mathematically describe and predict the solubility, spectral properties, protonation equilibrium constants and two-phase partitioning behavior of solutes dissolved in binary solvent mixtures of analytical importance. Information gained provide a better understanding of solute-solvent and solvent-solvent interactions at the molecular level, which will facilitate the development of better chemical separation… more
Date: August 1997
Creator: McHale, Mary E. R.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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