Physical Sciences and Mathematics Commons^™

Modulating Co2 Electrocatalytic Conversion To Organics Pathway By Nanoconfinement Effects And The Catalytic Site Dimension, Jianxin Wang

Graduate Research Theses & Dissertations

This dissertation presents a comprehensive study on the catalyst supports and the size of catalytic active sites. From a microscopic perspective, this research elucidates the implications of the nanoconfinement effects and the size effects of active sites in the electrocatalytic CO2 reduction process. It lays a solid foundation for the future development of superior catalysts.Electrochemical conversion of CO2 into value-added fuels and chemical feedstocks can serve future energy demands by storing renewable energy and reducing anthropogenic emissions of CO2. CO2 reduction reaction (CO2RR) to multi-carbon chemicals have generated growing interest in recent years, stimulated not only by the economic benefit …

Pathology And Diagnosis In Inflammatory-Related Diseases: Covid-19 And Age-Related Macular Degeneration, Zane Russell Lacasse

Graduate Research Theses & Dissertations

Chronic inflammation and dysfunctional inflammatory responses are believed to be contributing factors to the severity of many diseases. Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it has been recognized that levels of inflammatory markers and the severity of coronavirus disease-2019 (COVID-19) cases are closely related. The work within this dissertation begins with establishing an alternative platform for the diagnosis of COVID-19 and explores ways to enhance the diagnostic utility of this platform. An alternative route for COVID-19 diagnosis was explored using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS). The platform utilizes a non-invasive sampling technique …

Gas-Phase Mass Spectrometry Studies Of Ternary Metal Carboxylate Complexes, Anthony James Fanizza

Graduate Research Theses & Dissertations

In the wake of climate change from rising CO2 emissions and with peak oil looming, the dive into sustainable fuels and energy is becoming increasingly essential. This dissertation investigates ternary ligand-metal cationic complexes for potential catalytic applications in the decarboxylation of carboxylic acids to produce bioavailable and carbon-neutral fuel sources. By utilizing gas-phase reactivity studies via mass spectrometry, namely, collision-induced dissociation and ion-molecule reactions, mechanisms can be elucidated in a regulated chemical environment. When paired with density functional theory calculations for molecular geometries, chemical interactions, charge densities, and energetics, system efficiencies can be further clarified presenting a more complete mechanistic …

Advanced General Chemistry, Alexandra E. Strom

Open Educational Resources: Textbooks

Textbook adapted for CHM 118 at Smith College:

This course is for students with a very strong background in chemistry. The elementary theories of stoichiometry, atomic structure, bonding, structure, energetics and reactions are quickly reviewed. The major portions of the course involve a detailed analysis of atomic theory and bonding from an orbital concept, an examination of the concepts behind thermodynamic arguments in chemical systems, and an investigation of chemical reactions and kinetics. The laboratory deals with synthesis, physical properties and kinetics.

Mixed Quantum/Classical Calculations Of Rotationally Inelastic Scattering In The Co + Co System: A Comparison With Fully Quantum Results, Dulat Bostan, Bikramaditya Mandal, Carolin Joy, Michał Żółtowski, François Lique, Jérôme Loreau, Ernesto Quintas-Sánchez, Adrian Batista-Planas, Richard Dawes, Dmitri Babikov

Chemistry Faculty Research and Publications

An updated version of the CO + CO potential energy surface from [R. Dawes, X. G. Wang and T. Carrington, J. Phys. Chem. A 2013, 117, 7612] is presented, that incorporates an improved treatment of the asymptotic behavior. It is found that this new surface is only slightly different from the other popular PES available for this system in the literature [G. W. M. Vissers, P. E. S. Wormer and A. Van Der Avoird, Phys. Chem. Chem. Phys. 2003, 5, 4767]. The differences are quantified by expanding both surfaces over a set of analytic functions and comparing the behavior of …

Nanoscale Studies Of Magnesium Carbonate Precipitation At Ambient Conditions, Ian Shortt

Material Science and Engineering Dissertations

Currently approximately 8% of global greenhouse gas emissions can be attributed to the construction industry; of these emissions, a little over half of these emissions are due to the production of traditional calcium-based cements. Magnesium carbonate cements present a promising alternative to traditional calcium-based cements, both in terms of emission reductions and in terms of strength. The primary drawback to magnesium carbonate cements is that ambient curing is not yet viable. The objective of this dissertation is to therefore develop greater understanding of the precipitation pathways undertaken by hydrated magnesium carbonates under near-ambient conditions. In the first section of this …

Role Of Relative Humidity In New Particle Formation From Ozonlysis Of Atmospheric Volatile Organic Compounds, Christopher Snyder

Graduate College Dissertations and Theses

The impact of relative humidity (RH) on organic new particle formation (NPF) from ozonolysis of biogenic volatile organic compounds (BVOCs) remains an area of active debate. Previous reports provide contradictory results indicating both depression and enhancement of NPF under conditions of moderate RH, while others ignore the potential impact. Only several reports have suggested that the effect may depend on absolute mixing ratio of the precursor volatile organic compound (VOC, ppbv). However, before any experiments could be completed, development of new methods was necessary to overcome the limitation of sampling ultrafine nanoparticles (<50 nm aerodynamic diameter) with aerosol mass spectrometry. This dissertation includes a report on a new Particle Growth Apparatus (PaGA) that artificially grows particles from as small as 17 nm to over 110nm. Considerable effort was made to identify the most suitable growth matrix (squalane) and optimize particle growth for reproducibility and sensitivity.

The PaGA was then utilized in the …

Understanding Catalyst Design Principles In Transition Metal Mixed Anionic Chalcogenides For Electrocatalytic Energy Conversion, Ibrahim Abdullahi

Doctoral Dissertations

"This research focused on the synthetic design of transition metal mixed anionic chalcogenide catalysts containing various ligand types around the central metal atom (chalcogen anion and chalcogen-based organic ligand) generating diverse crystal structure types applied for water splitting and carbon dioxide reduction reactions (CO₂RR).

A series of catalysts were synthesized starting with isolated metal complexes (ME_n) with a central metal core (M = Co, Ni, Cu, and Cr) through molecular clusters, to bulk nanostructured solids of similar M-E coordination. Bis(dichalcogenoimidodiphosphinato) were employed as ligands in the metal complexes, and anionic chalcogen (E = S, Se, and …

Multiple Imputation For Robust Cluster Analysis To Address Missingness In Medical Data, Arnold Harder, Gayla R. Olbricht, Godwin Ekuma, Daniel B. Hier, Tayo Obafemi-Ajayi

Mathematics and Statistics Faculty Research & Creative Works

Cluster Analysis Has Been Applied To A Wide Range Of Problems As An Exploratory Tool To Enhance Knowledge Discovery. Clustering Aids Disease Subtyping, I.e. Identifying Homogeneous Patient Subgroups, In Medical Data. Missing Data Is A Common Problem In Medical Research And Could Bias Clustering Results If Not Properly Handled. Yet, Multiple Imputation Has Been Under-Utilized To Address Missingness, When Clustering Medical Data. Its Limited Integration In Clustering Of Medical Data, Despite The Known Advantages And Benefits Of Multiple Imputation, Could Be Attributed To Many Factors. This Includes Methodological Complexity, Difficulties In Pooling Results To Obtain A Consensus Clustering, Uncertainty Regarding …

Corrosion Inhibitors: Mitigating The Degradation Of Rebar, Jake R. Hughes

Williams Honors College, Honors Research Projects

Our conjecture was twofold: first, that two compounds historically used as food preservatives could act as environmentally friendly inhibitors against rebar corrosion, and second, that molecular properties have a quantifiable influence on inhibition efficiency (%IE). To evaluate the two compounds, cyclic potentiodynamic polarization was used to determine corrosion current density (i_corr) and %IE. The “green” inhibitor candidates included sodium metabisulfite and ascorbic acid, which yielded maximum %IE values of -123900% and 91%, respectively. Results indicated that sodium metabisulfite is not a suitable inhibitor, while ascorbic acid showed potential to extend reinforced concrete’s design life without posing health or …

Post Polymerization Modification And Preparation Of Dynamic Polymer Networks Via Guanylation Of Aryl Carbodiimides, Conner J. Klingler

WWU Graduate School Collection

Styrenic carbodiimide (CDI) polymers have shown an interesting ability to form reversible polymer networks, known as covalent adaptable networks (CANs), through an uncatalyzed reaction with multifunctional amines. CANs have been a topic of interest in polymer chemistry due to their ability to be reprocessed, which is not found in classic thermoset polymer networks. However, not much is known about the capabilities of the nucleophilic addition of amines to aryl CDI repeat unit structures that goes into making these networks due to the understudied reactions involved. This thesis aims to develop a better understanding of the chemistry involved through various post …

Highly Dipole-Parallel Aligned Nonlinear Optical Organic Molecular Crystalline Materials: Rational Design, Experimental And Theoretical Studies Of Supramolecular Structures And Non-Covalent Interactions, Harmeet Singh Bhoday

Doctoral Dissertations

Highly dipole-parallel aligned donor-acceptor substituted organic molecules are attractive for a wide array of applications, including nonlinear optics. However, only a limited number of crystals are known to adopt polar non-centrosymmetric space groups. The concepts guiding the fabrication of these polar materials have been described. The study focused on unsymmetrical donor-acceptor substituted azines and butadiene's. An improved design over (MeO, Y)-azines led to the realization of three crystals perfectly aligned in dipole parallel orientation for (PhO, Y)-azines with Y = Cl, Br, I, and one nearly perfectly aligned crystal for Y = F (Paper I). The unique bonding properties associated …

Tracking The Reaction Networks Of Criegee Intermediates Formed In The Ozone-Assisted Oxidation Reactions Of C5 Acyclic And Endocyclic Alkenes, Arden M. Floyd

Honors Undergraduate Theses

Uni- and bi-molecular reactions involving Criegee intermediates (CIs), characteristic to alkene-ozone reactions, play an important role in synthetic organic, atmospheric, and combustion chemistry. However, difficulty in detecting key intermediates has prevented a thorough understanding of the details of the ozonolysis mechanism. To gain new insights into how alkene structure affects the CI network, the ozone assisted oxidation reactions of trans-2-pentene and cyclopentene are investigated between 320 K and 760 K in an atmospheric pressure jet stirred reactor (JSR). Molecular-beam mass spectrometry in conjunction with single photon tunable synchrotron VUV radiation is used to identify elusive intermediates by means of …

Shifting Educational Paradigms: An Analysis Of Evolving Student Expectations Within A Reformed Physical Chemistry Curriculum, Kevin E. Morales

Honors Undergraduate Theses

Students often hold negative expectations when enrolling in rigorous undergraduate courses. PhysicalChemistry is a challenging upper-level course for Chemistry majors; the course has a reputation as a demandingcourse that leads to students building negative expectations. This worsened when ambiguity existed in an instructor’s pedagogy. Not addressing those initial expectations of the students abates their motivation, which does not put them in the best place to learn, leading to poor academic performance. The course syllabus is often the first interaction a student has with the course; it can be a critical tool in (re)setting students' initial expectations and allows the instructor …

Numerical Solution Of Hybrid Nanofluid And Its Stability Over Permeable Wedge Sheet With Heat Transfer Analysis, Aisha M. Alqahtani, Zeeshan, Waris Khan, Florentin Smarandache, Nidhal Becheikh, Roobaea Alroobaea, Taseer Muhammad

Branch Mathematics and Statistics Faculty and Staff Publications

The inclusion of nanoparticles has the potential to improve the thermal efficiency of the base fluid. The field of nanofluid (NF) dynamics has attracted important attention due to its extensive range of practical uses like fuel cells, solar energy, medication administration, heat transfer, microfabrication, coolant applications, and other related domains. The aim of this study is to scrutinize the impact of Lorentz force, thermal energy, joule heating, heat source and injection parameters, and Brownian and thermoporetic diffusions on the hybrid nanofluid over the moving wedge. The stability inquiry is reported for the existing work in order to confirm the stable …

Immobilization Of Thiol-Modified Horseradish Peroxidase On Gold Nanoparticles Enhances Enzyme Stability And Prevents Proteolytic Digestion, Faith E. Breausche, Annelise Somerlot, Jason Walder, Kwame Osei, Samuel Okyem, Jeremy D. Driskell

Faculty Publications – Chemistry

The specificity and efficiency of enzyme-mediated reactions have the potential to positively impact many biotechnologies; however, many enzymes are easily degraded. Immobilization on a solid support has recently been explored to improve enzyme stability. This study aims to gain insights and facilitate enzyme adsorption onto gold nanoparticles (AuNPs) to form a stable bioconjugate through the installation of thiol functional groups that alter the protein chemistry. In specific, the model enzyme, horseradish peroxidase (HRP), is thiolated via Traut’s reagent to increase the robustness and enzymatic activity of the bioconjugate. This study compares HRP and its thiolated analog (THRP) to deduce the …

Quantum Interference Enhancement Of The Spin-Dependent Thermoelectric Response, Runa X. Bennett, Joshua R. Hendrickson, Justin P. Bergfield

Faculty publications – Physics

We investigate the influence of quantum interference (QI) and broken spin-symmetry on the thermoelectric response of node-possessing junctions, finding a dramatic enhancement of the spin-thermopower (Ss), figure-of-merit (ZsT), and maximum thermodynamic efficiency (ηsmax) caused by destructive QI. Using many-body and single-particle methods, we calculate the response of 1,3-benzenedithiol and cross-conjugated molecule-based junctions subject to an applied magnetic field, finding nearly universal behavior over a range of junction parameters with Ss, ZsT, and reaching peak values of 2𝜋/ √3(𝑘/𝑒)2𝜋/3(𝑘/𝑒), 1.51, and 28% of Carnot efficiency, respectively. We also find that the …

Sequential Infiltration Synthesis Of Silicon Dioxide In Polymers With Ester Groups─Insight From In Situ Infrared Spectroscopy, Mahua Biswas, Vepa Rozyyev, Anil U. Mane, Amelia Korveziroska, Uttam Manna, Jeffrey W. Elam

Faculty publications – Physics

New strategies to synthesize nanometer-scale silicon dioxide (SiO2) patterns have drawn much attention in applications such as microelectronic and optoelectronic devices, membranes, and sensors, as we are approaching device dimensions shrinking below 10 nm. In this regard, sequential infiltration synthesis (SIS), a two-step gas-phase molecular assembly process that enables localized inorganic material growth in the targeted reactive domains of polymers, is an attractive process. In this work, we performed in situ Fourier transform infrared spectroscopy (FTIR) measurements during SiO2 SIS to investigate the reaction mechanism of trimethylaluminum (TMA) and tri(tert-pentoxy) silanol (TPS) precursors with polymers having ester functional groups (poly(methyl …

Reducing Short-Chain Pfas Levels In California Water Supplies, Manu Prabandham

Pomona Senior Theses

This thesis proposes twelve specific policies based on precedents set by prior regulation of persistent organic pollutants (such as PCBs), the costs and benefits of short-chain PFAS, technologies available to remove and destroy short-chain PFAS, and the roles and limitations of California’s regulatory institutions. The twelve policies are chosen to be politically and financially feasible, effective at removing short-chain PFAS from water supplies, and equitable towards lower-income and minority Californians, who suffer the most from the consequences of PFAS and other environmental pollutants. The new definitions, education campaigns, studies, taxes, bans, standards, testing, and filtration systems proposed are intended to …

Antibody-Driven Assembly Of Plasmonic Core–Satellites To Increase The Sensitivity Of A Sers Vertical Flow Immunoassay, Eunice Ebbah, Anthony Amissah, Jun-Hyun Kim, Jeremy D. Driskell

Faculty Publications – Chemistry

Here, we describe a SERS-based vertical flow assay as a platform technology suitable for point-of-care (POC) diagnostic testing. A capture substrate is constructed from filter paper embedded with spherical gold nanoparticles (AuNPs) and functionalized with an appropriate capture antibody. The capture substrate is loaded into a filtration device and connected to a syringe to rapidly and repeatedly pass the sample through the sensor for efficient antigen binding. The antigen is then labeled with a SERS-active detection probe. We show that only a few Raman reporter molecules, exclusively located adjacent to the plasmonic capture substrate, generate detectible signals. To maximize the …

Diastereoselective Synthesis Of The Hiv Protease Inhibitor Darunavir And Related Derivatives Via A Titanium Tetrachloride-Mediated Asymmetric Glycolate Aldol Addition Reaction, Jordan M. Witte, Emmanuel Ayim, Christopher J. Sams, Jasmine B. Service, Caitlyn C. Kant, Lillian Bambalas, Daniel Wright, Austin Carter, Kelly Moran, Isabella G. Rohrig, Gregory M. Ferrence, Shawn R. Hitchcock

Faculty Publications – Chemistry

Darunavir is a potent HIV protease inhibitor that has been established as an effective tool in the fight against the progression of HIV/AIDS in the global community. The successful application of this drug has spurred the development of derivatives wherein strategic regions (e.g., P1, P1’, P2, and P2’) of the darunavir framework have been structurally modified. An alternate route for the synthesis of darunavir and three related P1 and P1’ derivatives has been developed. This synthetic pathway involves the use of a Crimmins titanium tetrachloride-mediated oxazolidine-2-thione-guided asymmetric glycolate aldol addition reaction. The resultant aldol adduct introduces the P1 fragment of …

Revealing Binding And Unbinding Pathways Of Small Molecules And Peptides To Enzymes With Enhanced Sampling Methods, Kayla Ariana Croney

WWU Graduate School Collection

In vitro experiments are critical to understanding the biochemistry of molecular systems but it can be a challenge to obtain atomistic resolution. Computational chemistry gives insight to these results with molecular dynamics (MD) simulations using Newton’s equations of motion to analyze the motion of atoms and molecules. However, due to insufficient sampling and long-lived metastable states separated by high energy intermediates, enhanced sampling methods must be applied. Metadynamics (MetaD) enhances the exploration of MD by adding time-dependent bias. Here, we applied MetaD to two enzymes to study their substrate binding/unbinding pathways with their respective substrates. Yeast cytosine deaminase (yCD) deaminates …

Transition State Kinetics Through Kramers’ Rate For Variationally Enhanced Sampling., David Cummins

WWU Graduate School Collection

Molecular Dynamics (MD) simulations use Newtonian mechanics applied at finite time steps to numerically propagate the time-trajectory of a dynamical system. However, many biochemical processes such as catalysis, ion channel gating, substrate binding, and protein folding evolve over time scales which are orders of magnitudes greater than those afforded by MD and the computational power available today. The development of methods that reduce the computational cost of sampling such rare events help to provide a dynamic insight into these processes. This thesis explores the application of a recently developed enhanced sampling method, Variationally Enhanced Sampling (VES), for calculating kinetic rate …

Synthesis And Dft Investigations Of Silver Nanocubes Coated With Gold Layers For Enhanced Stability, Ayomide Daniel Oluwafemi

WWU Graduate School Collection

Silver nanocubes (Ag nanocubes) are one of the most important nanostructures, due to their plasmonic capabilities. However, their susceptibility to oxidation upon exposure leads to rounding of their edges or sharp corners, compromising quality and stability. A feasible option to address this issue is to deposit a second metal, such as gold (Au), which is resistant to oxidation, onto the Ag nanocubes. Regrettably, manipulating the synthetic parameters that shape Au coated Ag nanocubes is difficult. The galvanic replacement reaction between Au and Ag can erode, hollow, and disintegrate the Ag nanocubes. We explore several synthetic pathways to achieve well-controlled shaped …

Elucidating The Binding Characteristics Of Lrp1 In Factor Viii Blood Coagulation, Nicole Topor-Madry

WWU Graduate School Collection

Abstract

Factor VIII and von Willebrand factor (vWF) are essential for blood coagulation. FVIII, a large glycoprotein with 2332 amino acids, is crucial in the intrinsic pathway of coagulation. After secretion, FVIII circulates in the bloodstream at approximately one nanomolar concentration, bound to vWF, which protects it from rapid clearance. In response to vascular injury, FVIII is proteolytically activated, dissociates from vWF, and binds to activated platelet surfaces and activated Factor IX, dramatically accelerating the rate of blood clot formation. Hemophilia A, affecting 1 in 5000 males, results from functional FVIII deficiency. Standard treatment involves prophylactic FVIII injections but has …

Examining The Nexus Between Scientific Literacy And Identity In General Chemistry, Tiffany Chamberlain

WWU Graduate School Collection

Scientific literacy is a crucial goal of science education. All citizens need scientific understanding to make rational and informed decisions, and to feel confident in making such decisions. Many students harbor doubts about belonging in science and their identities as science persons. As such, science educators are tasked with helping students develop these skills as they engage in various courses. College instructors incorporate scientific literacy skills as part of their courses in which students are encouraged to develop a science person identity (i.e. science identity) through science identity work. Therefore, learning can be seen as a process of identity …

C–H Alkylation Of Diol Substrates Using Bifunctional Boronic Acid Catalysts, Matthew Ryan Ross

Graduate Theses, Dissertations, and Problem Reports

Boronic acid catalysts in combination with a Lewis base have been used in previous work to perform site-selective C–H alkylation reactions targeting the α-hydroxy C–H bond of diols through a photoredox activated hydrogen atom transfer. This is done by accessing a tetracoordinate boronic acid – Lewis base complex which then mediates the hydrogen atom transfer. The research hypothesizes that combining the boronic acid and Lewis base into one molecule not only simplifies the reaction but also has the potential to unlock C–H alkylation sites previously inaccessible. This is plausible because the Lewis base portion of the synthesized bifunctional boronic acid …

Synthetic Elaboration Of Β-Carbonyl Alkylboronic Esters, Mason D. Hamilton Ph.D.

Graduate Theses, Dissertations, and Problem Reports

Organoboron compounds are some of the most synthetically versatile compounds in organic chemistry due to the many valuable transformations of the C-B bond. This synthetic versatility combined with the pharmacophoric nature of carboxylic acids has led to an increased interest in the one-pot difunctionalization of vinyl arenes using CO₂ and pinacol boranes. Recently, much progress has been made to improve the scope and versatility of boracarboxylation reactions to now include electron-deficient and α-methyl substituted vinyl arenes. However, the potential transformations of boracarboxylated products have remained unexplored. Here, methodologies to transform the β-aryl alkylboronic ester into new C-C, C-N, and …

Additive-Dependent Regioselective Boracarboxylation Of Alkenes Using Low Valent Copper And Co2, Carly H. Gordon Ph.D.

Graduate Theses, Dissertations, and Problem Reports

As a major greenhouse gas, carbon dioxide (CO₂) is an abundant and renewable C₁ feedstock, and developing methods for fixing CO₂ into high-value products is a major interest for the movement of greener chemistry. The boracarboxylation of alkenes provides access to difunctionalized products containing pharmaceutically relevant motifs, including carboxylic acids and boron-containing moieties. Significant work has been done to improve the versatility and efficiency of this methodology, with the recent expansion into a wide variety of terminal alkenes. The use of different phosphine and alkene additives have demonstrated positive effects on reaction rates and productivity, indicating …

Experimental And Chemical Modeling Of Applied Dc Electric Field Induced H2 – Air Axisymmetric Laminar Co-Flow Diffusion Flames With Low Carbon Impurities, Susith Dilshan Pathmasiri Gunamuni Halowitage

Graduate Theses, Dissertations, and Problem Reports

The effect of externally applied DC electric fields on flame structure was investigated in a stationary atmospheric axisymmetric laminar H₂–Air flame with less than 100 ppm carbon equivalent impurities. Flame OH chemiluminescence signals were recorded using a UV-sensitive CCD array as a function of voltage (+10 to -10 kV) applied to a stainless-steel ring electrode placed around the burner nozzle. Changes in chemiluminescence signal are reported as a function of electrode height above the burner, airflow, and fuel composition. Significant changes in OH* distributions were observed for voltages below -5 kV. Under optimum conditions, the height of the …