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Avoiding The Cubic Equation In Finding The Van Der Waals Fluid's Vapor Pressures, Carl W. David 2017 University of Connecticut

Avoiding The Cubic Equation In Finding The Van Der Waals Fluid's Vapor Pressures, Carl W. David

Chemistry Education Materials

The van der Waals coexistence curve of liquid and vapor volumes as functions of the temperature (all in reduced coordinates) as well as the correspponding vapor pressures at these temperatures, is obtained using SageMath, a symbolic calculus/algebra computer programming language.The lack of correspondence of the coexistence locus’ analytical form as obtained herein and those of Lekner remains disconcerting.


Construction And Analysis Of Accurate Exchange-Correlation Potentials, Sviataslau V. Kohut 2017 The University of Western Ontario

Construction And Analysis Of Accurate Exchange-Correlation Potentials, Sviataslau V. Kohut

Electronic Thesis and Dissertation Repository

Practical Kohn–Sham density-functional calculations require approximations to the exchange-correlation energy functional, EXC[ρ], or the exchange-correlation potential, vXC(r), defined as the functional derivative of EXC[ρ] with respect to the electron density, ρ. This thesis focuses on the following problems: (i) development of approximate exchange-correlation potentials by modelling the exchange-correlation charge distribution; (ii) accurate approximation of functional derivatives of orbital-dependent functionals; (iii) generation of exchange-correlation potentials from many-electron wavefunctions; (iv) analysis of accurate exchange-correlation potentials in atoms and molecules.

The advantage of modelling the exchange-correlation potential through the exchange-correlation charge distribution, qXC(r), is ...


Nanoparticle-Based Drug-Delivery Systems Studied By Second Harmonic Generation, Raju Ram Kumal 2017 Louisiana State University and Agricultural and Mechanical College

Nanoparticle-Based Drug-Delivery Systems Studied By Second Harmonic Generation, Raju Ram Kumal

LSU Doctoral Dissertations

Second harmonic generation (SHG) is used to study different types of colloidal nanoparticle drug-delivery systems. The surface charge density, electrostatic surface potentials, and ion adsorptions of 50 nm colloidal gold nanoparticle samples coated with mercaptosuccinic acid are determined using SHG measurements under varying NaCl and MgCl2 concentrations in water. Numerical solutions to the spherical Poisson-Boltzmann equation are fit to the SHG results to account for the nanoparticle surface curvature and ion adsorption to the Stern layer interface, showing excellent agreement with electrophoretic mobility measurements. In another study, nanoparticles of gold, silver and polystyrene are functionalized with microRNA using a ...


Raman Spectroscopy Of Oxygen Evolution Catalysts And Psii Manganese Model Compounds, Sergei Shmakov, Daniel A. Hartzler, Alireza Karbakhsh Ravari, Yulia Pushkar 2017 Purdue University

Raman Spectroscopy Of Oxygen Evolution Catalysts And Psii Manganese Model Compounds, Sergei Shmakov, Daniel A. Hartzler, Alireza Karbakhsh Ravari, Yulia Pushkar

The Summer Undergraduate Research Fellowship (SURF) Symposium

Photosynthesis is the basis of life on earth, and oxygen evolution catalysts are key components of this complicated, yet not fully understood process. Photosystem II, a large membrane bound pigment-protein complex, is the key system that facilitates oxygenic photosynthesis via the oxygen evolving complex (a natural oxygen evolving catalyst). It is a key component in oxygen producing catalysts, which can be used in fields such as energy production and biomimetic catalysts. The oxygen evolution cycle, or Kok cycle going within it is still not studied completely. In this project, we were studying the vibrational (and structural) state of a Manganese ...


Applying Machine Learning To Computational Chemistry: Can We Predict Molecular Properties Faster Without Compromising Accuracy?, Hanjing Xu, Pradeep Gurunathan, Lyudmila Slipchenko 2017 Purdue University

Applying Machine Learning To Computational Chemistry: Can We Predict Molecular Properties Faster Without Compromising Accuracy?, Hanjing Xu, Pradeep Gurunathan, Lyudmila Slipchenko

The Summer Undergraduate Research Fellowship (SURF) Symposium

Non-covalent interactions are crucial in analyzing protein folding and structure, function of DNA and RNA, structures of molecular crystals and aggregates, and many other processes in the fields of biology and chemistry. However, it is time and resource consuming to calculate such interactions using quantum-mechanical formulations. Our group has proposed previously that the effective fragment potential (EFP) method could serve as an efficient alternative to solve this problem. However, one of the computational bottlenecks of the EFP method is obtaining parameters for each molecule/fragment in the system, before the actual EFP simulations can be carried out. Here we present ...


Temperature-Dependent Exciton Dynamics Of Superacid Treatment In Monolayers Of The Metal Dichalcogenide Mos2, Mingwei Zhou, Long Yuan, Jordan Snaider, Libai Huang 2017 Purdue University

Temperature-Dependent Exciton Dynamics Of Superacid Treatment In Monolayers Of The Metal Dichalcogenide Mos2, Mingwei Zhou, Long Yuan, Jordan Snaider, Libai Huang

The Summer Undergraduate Research Fellowship (SURF) Symposium

To improve optoelectronic semiconductor materials, one of the most efficient research areas is the two-dimensional (2D) transition-metal dichalocogenides (TMDCs). It has been shown that organic nonoxidizing superacid bis(trifluoromethane)sulfonamide (TFSI) treatment of molybdenum disulfide (MoS2) monolayer could uniformly enhance its photoluminescence by more than two orders of magnitude and also extend the lifetime of excitons. This could greatly improve the efficiency of the solar energy usage, but the mechanism behind it has not been fully understood. Extreme low temperatures (approximately 7K), which slow the surface exciton mobility, were applied to investigate the changes of treated MoS2 monolayer ...


Synthesis And Catalytic Evaluation Of Novel C-Alpha-Methyl-Beta-Proline Analogues, And Concise Synthetic Approach To Nh-Fmoc-S-Trityl-C-Alpha-Methyl Cysteine, Hari Kiran Kotapati 2017 University of Southern Mississippi

Synthesis And Catalytic Evaluation Of Novel C-Alpha-Methyl-Beta-Proline Analogues, And Concise Synthetic Approach To Nh-Fmoc-S-Trityl-C-Alpha-Methyl Cysteine, Hari Kiran Kotapati

Dissertations

In the field of chemistry there is a growing demand for small molecule organocatalysts such as amino acids, more specifically proline and its analogues, which could catalyze various key chemical reactions in the synthesis of several biologically important molecules. Even though natural proline is reported to catalyze various chemical reactions, its use as organocatalyst is limited mainly due to the solubility issues in the reaction media and high catalyst loadings, which is not very ideal for bulk scale manufacturing. To address these limitations we planned to develop unnatural analogues of proline that could catalyze the reactions with lower catalyst loadings ...


Novel Design Strategies For Platinum-Containing Conjugated Polymers And Small Molecules For Organic Solar Cells, Wenhan He 2017 University of New Mexico

Novel Design Strategies For Platinum-Containing Conjugated Polymers And Small Molecules For Organic Solar Cells, Wenhan He

Chemistry ETDs

Current state-of-the-art organic solar cells (OSCs) adopt the strategy of using conjugated polymers or small molecules as donors and fullerene derivatives as acceptors in their active layers. Regarding to the donors of interest, the conjugated polymers and small molecules coupled with heavy metals have been less explored compared to their counterparts. Among various transition metal complexes applied, Pt(II) complexes are unique because of their intrinsic square planar geometries and ability to serve as building blocks for conjugated systems. Furthermore, the heavy metal Pt facilitates the formation of triplet excitons with longer life times through spin-orbital coupling which are of ...


Exploring Two Approximate Coupling Models In Exciton Transport, James Irish-Ryan 2017 DePaul University

Exploring Two Approximate Coupling Models In Exciton Transport, James Irish-Ryan

DePaul Discoveries

Point dipole and line dipole coupling approximations are two methods for approximating the transition dipole coupling between two conjugated organic molecules. Transition dipole couplings are an important factor in determining energy transfer between two non-covalently-bonded molecules. Transition dipole couplings were mathematically calculated by two methods, applying the point dipole and line dipole approximations. The calculations were implemented using Octave, an open source computer programming language. Using this tool, software was created to efficiently analyze the differences between transition dipoles calculated using the two methods, for a variety of relative orientations of two model conjugated organic molecules. Custom-built software was created ...


Mixed Quantum/Classical Theory (Mqct) For Rotationally And Vibrationally Inelastic Scattering And Its Application To The Molecules Of Astrochemical Importance, Alexander Semenov 2017 Marquette University

Mixed Quantum/Classical Theory (Mqct) For Rotationally And Vibrationally Inelastic Scattering And Its Application To The Molecules Of Astrochemical Importance, Alexander Semenov

Dissertations (2009 -)

This thesis presents developments and applications of the mixed quantum/classical theory (MQCT) for inelastic scattering. In this approach, translational motion of collision partners is treated classically, while the internal degrees of freedom – rotational and/or vibrational motion – are treated quantum mechanically. Within this framework calculations of rotationally inelastic cross sections are carried out in a broad range of collision energies and results are compared against the exact full quantum data for several real systems. For CO +He, N2 + Na and H2 + He the agreement is excellent through six orders of magnitude range of cross sections values and for energies ...


Functional And Structural Studies Of Cytochromes P450 By Resonance Raman Spectroscopy, Yilin Liu 2017 Marquette University

Functional And Structural Studies Of Cytochromes P450 By Resonance Raman Spectroscopy, Yilin Liu

Dissertations (2009 -)

Cytochrome P450 is a broad class of heme monooxygenase enzymes which catalyze various oxidative transformations. There are two main kinds of mammalian P450s: steroidogenic and drug metabolizing P450s. The first project involves a steroidogenic P450, CYP17A1, occupying a central role in the biosynthesis of steroid hormones. It catalyzes hydroxylation reaction on pregnenolone and progesterone, generating 17OH-pregnenolone and 17OH-progesterone, presumably utilizing a “Compound I” species. However, these hydroxylated products can be further processed in a second oxidative cycle to cleave the C17–C20 bond to form dehydroepiandrosterone or androstenedione, respectively, a crucial step in androgen production. Interestingly, it is well known ...


Comparative Study Of The Tribological And Oxidative Properties Of Alpdmn Quasicrystals And Their Cubic Approximants, Chris Mancinelli, Jeff S. Ko, Cynthia J. Jenks, Patricia A. Thiel, Amy R. Ross, Thomas A. Lograsso, Andrew J. Gellman 2017 Carnegie Mellon University

Comparative Study Of The Tribological And Oxidative Properties Of Alpdmn Quasicrystals And Their Cubic Approximants, Chris Mancinelli, Jeff S. Ko, Cynthia J. Jenks, Patricia A. Thiel, Amy R. Ross, Thomas A. Lograsso, Andrew J. Gellman

Thomas A. Lograsso

An experimental comparison has been made between the properties of the surfaces of an Al70Pd21Mn9quasicrystal and its Al48Pd42Mn10 approximant. The Al70Pd21Mn9 sample was a single grain icosahedral quasicrystal cut to expose its five-fold symmetric (000001) surface. The approximant was polycrystalline β-phase Al48Pd42Mn10, which has a CsCl-type cubic structure. Surfaces of both were prepared under ultra-high vacuum (UHV) conditions and then used for comparative measurements of their frictional properties and oxidation rates. Both materials are oxidized by reaction with O ...


Evolution Of Cu2o Morphology During Copper Corrosion In The Presence Of Gamma-Radiation, Arielle M. Jean 2017 The University of Western Ontario

Evolution Of Cu2o Morphology During Copper Corrosion In The Presence Of Gamma-Radiation, Arielle M. Jean

Electronic Thesis and Dissertation Repository

In this work, experiments were carried out in order to develop a mechanistic understanding of the corrosion of copper metal in limited water volumes under gamma-radiation. When exposed to gamma-radiation, water decomposes into chemically reactive oxidizing and reducing species. Under a continuous radiation flux, the concentrations of the radiolytically produced oxidants eventually reach a pseudo-steady state that can influence the corrosion kinetics of metallic surfaces.

The evolution of the surface morphology during water droplet corrosion of copper in the presence of gamma-radiation was investigated as a function of irradiation time and pH. The oxide growth kinetics were studied by measuring ...


The Mathematical Structure Of Arrangement Channel Quantum Mechanics, James W. Evans 2017 Iowa State University

The Mathematical Structure Of Arrangement Channel Quantum Mechanics, James W. Evans

James W. Evans

A non-Hermitian matrix Hamiltonian H appears in the wavefunction form of a variety of many-body scattering theories. This operator acts on an arrangement channel Banach or Hilbert space 1(;' = Ell ncr where ,r is the N-particle Hilbert space and a are certain arrangement channels. Various aspects of the spectral and semigroup theory for H are considered. The normalizable and weak (wavelike) eigenvectors ofH are naturally characterized as either physical or spurious. Typically H is scalar spectral and "equivalent" to H on an H-invariant subspace of physical solutions. If the eigenvectors form a basis, by constructing a suitable biorthogonal system, we ...


Heterogeneous Multicatalytic System For Single-Pot Oxidation And C–C Coupling Reaction Sequences, Nicholas C. Nelson, Umesh Chaudhary, Kapil Kandel, Igor I. Slowing 2017 Iowa State University

Heterogeneous Multicatalytic System For Single-Pot Oxidation And C–C Coupling Reaction Sequences, Nicholas C. Nelson, Umesh Chaudhary, Kapil Kandel, Igor I. Slowing

Igor I. Slowing

A system comprising two catalysts supported on mesoporous silica nanoparticles (MSNs) was employed to perform a sequence of two reactions in a single pot. Palladium nanoparticles catalyzed the oxidation of furfuryl alcohol with molecular oxygen at atmospheric pressure. The oxidation product, furfural, was then reacted with acetone via an aldol condensation catalyzed by amines supported on MSNs. Each reaction was first tested individually to establish optimal conditions. Both catalysts were then introduced into the same reactor under the proven conditions, and the entire reaction sequence was performed giving the desired product with high selectivity. The overall yield of the reaction ...


Supported Iron Nanoparticles For The Hydrodeoxygenation Of Microalgal Oil To Green Diesel, Kapil Kandel, James W. Anderegg, Nicholas C. Nelson, Umesh Chaudhary, Igor I. Slowing 2017 Iowa State University

Supported Iron Nanoparticles For The Hydrodeoxygenation Of Microalgal Oil To Green Diesel, Kapil Kandel, James W. Anderegg, Nicholas C. Nelson, Umesh Chaudhary, Igor I. Slowing

Igor I. Slowing

Iron nanoparticles supported on mesoporous silica nanoparticles (Fe-MSN) catalyze the hydrotreatment of fatty acids with high selectivity for hydrodeoxygenation over decarbonylation and hydrocracking. The catalysis is likely to involve a reverse Mars–Van Krevelen mechanism, in which the surface of iron is partially oxidized by the carboxylic groups of the substrate during the reaction. The strength of the metal–oxygen bonds that are formed affects the residence time of the reactants facilitating the successive conversion of carboxyl first into carbonyl and then into alcohol intermediates, thus dictating the selectivity of the process. The selectivity is also affected by the pretreatment ...


Substrate Inhibition In The Heterogeneous Catalyzed Aldol Condensation: A Mechanistic Study Of Supported Organocatalysts, Kapil Kandel, Stacey Marie Althaus, Chorthip Peeraphatdit, Takeshi Kobayashi, Brian G. Trewyn, Marek Pruski, Igor I. Slowing 2017 Iowa State University

Substrate Inhibition In The Heterogeneous Catalyzed Aldol Condensation: A Mechanistic Study Of Supported Organocatalysts, Kapil Kandel, Stacey Marie Althaus, Chorthip Peeraphatdit, Takeshi Kobayashi, Brian G. Trewyn, Marek Pruski, Igor I. Slowing

Igor I. Slowing

In this study, we demonstrate how materials science can be combined with the established methods of organic chemistry to find mechanistic bottlenecks and redesign heterogeneous catalysts for improved performance. By using solid-state NMR, infrared spectroscopy, surface and kinetic analysis, we prove the existence of a substrate inhibition in the aldol condensation catalyzed by heterogeneous amines. We show that modifying the structure of the supported amines according to the proposed mechanism dramatically enhances the activity of the heterogeneous catalyst. We also provide evidence that the reaction benefits significantly from the surface chemistry of the silica support, which plays the role of ...


Exocytosis Of Mesoporous Silica Nanoparticles From Mammalian Cells: From Asymmetric Cell-To-Cell Transfer To Protein Harvesting, Igor I. Slowing, Juan L. Vivero-Escoto, Yannan Zhao, Kapil Kandel, Chorthip Peeraphatdit, Brian G. Trewyn, Victor S.Y. Lin 2017 Iowa State University

Exocytosis Of Mesoporous Silica Nanoparticles From Mammalian Cells: From Asymmetric Cell-To-Cell Transfer To Protein Harvesting, Igor I. Slowing, Juan L. Vivero-Escoto, Yannan Zhao, Kapil Kandel, Chorthip Peeraphatdit, Brian G. Trewyn, Victor S.Y. Lin

Igor I. Slowing

The exocytosis of mesoporous silica nanoparticles (MSNs) from mammalian cells is demonstrated for the first time. The differences in the degree of exocytosis of MSNs between healthy and cancer cells are shown to be responsible for the asymmetric transfer of the particles between both cell types. The exo­cytosis of highly adsorbent magnetic MSNs proves to be useful as a means for harvesting biomolecules from living cells.


Conformational Studies Of Gram-Negative Bacterial Quorum Sensing 3-Oxo N-Acyl Homoserine Lactone Molecules, Darren Crowe, Alan Nicholson, Adrienne Fleming, Ed Carey, Goar Sanchez-Sanz, Fintan Kelleher 2017 Institute of Technology Tallaght

Conformational Studies Of Gram-Negative Bacterial Quorum Sensing 3-Oxo N-Acyl Homoserine Lactone Molecules, Darren Crowe, Alan Nicholson, Adrienne Fleming, Ed Carey, Goar Sanchez-Sanz, Fintan Kelleher

Articles

In their 1H NMR spectra in CDCl3 3-oxo-N-acyl homoserine lactones (OHLs) show significant downfield chemical shifts of the amide N-H proton when compared to the parent N-acyl homoserine lactones (AHLs). NMR spectroscopic and DFT calculation studies have shown that this is most likely due to the presence of a stabilising intramolecular H-bond from the N-H to the 3-oxo group. The 1H NMR spectra also show evidence for the enol tautomers and that the amount of enol present for a range of OHLs is 4.1-4.5% in CDCl3 and 6.5-7.2% in ...


The Investigation And Characterization Of The Reaction Of 2-Methylfuran And 2-Methyl-3-Buten-2-Ol With O(3p) And The Photodissociation Of Xylyl Bromide Isomers, Yasmin Fathi 2017 University of San Francisco

The Investigation And Characterization Of The Reaction Of 2-Methylfuran And 2-Methyl-3-Buten-2-Ol With O(3p) And The Photodissociation Of Xylyl Bromide Isomers, Yasmin Fathi

Master's Theses

This thesis has studied the oxidation behavior of different biofuels or additives, 2-methyl-3-buten-2-ol and 2-methylfuran, in combustion experiments at the Chemical Dynamics Beamline held at the Advanced Light Source of the Lawrence Berkley National Laboratory. The oxidation of these fuels were initiated through O(3P) and the combustion experiments were analyzed using a multiplexed chemical kinetics photoionization mass spectrometer with tunable synchrotron radiation. Products of the different reactions were identified using kinetic profiles and further characterized using the photoionization spectra. The amount of each species was calculated using branching fractions.

Additionally, the unimolecular dissociation of the xylyl bromide isomers ...


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