A sculpture can offer visual information that is simple or complex. The work can present only a single facet to ponder or deal with all facets equally polished and linked. There can be enough information to arrange in an order that reads as narrative. All is possible but, without question, the more complex the sculpture, the more information given, the greater the challenge to the artist to make a coherent and interesting whole of everything being presented. The body of work presented in my thesis show represents the outcome of exploring a chain of questions about sculpture. The first question was simply how to present a sculpture of a seed pod. This question led to inquiring what the base could do for the sculpture. Next came a study of the artwork of Constantin Brancusi. I realized that he had used formal qualities of sculpture to link his bases and sculptures, so I wondered about the ability of formal qualities to solve my base/sculpture problems. All of the work was completed with the intent of expanding my personal sculptural lexicon. I also intended to develop a store of knowledge that allowed free use of multiple artistic concepts. The hope was that what was being communicated through a sculpture would be sufficiently complex that a viewer would be intrigued into considering all the possible implications of the visual information.

Chemists use the electron-pushing formalism to rationalize, analyze, and explain how a chemical reaction occurs on an electronic level. The electron pushing formalism (EPF) is the curved arrows representing electron movement. Some research on undergraduate organic chemistry students’ understanding of the electron pushing formalism has presented evidence that some students do not find the electron-pushing formalism meaningful. Research at the University of Ottawa found that the EPF symbolism is meaningful to the participants because they interpret EPF arrows and use charges and mapping to problem-solve. At the University of Ottawa, the organic chemistry curriculum was changed in 2012 to have students learn and interpret reactions based on similar reactivity patterns. The goal of the redesign was to give students the tools to analyze, predict, and explain how reactions occur instead of memorizing. An initial section of the curriculum is dedicated to teaching the electron-pushing formalism before any reaction. An exam analysis was conducted to see the new curriculum's effect by looking at students' drawn structures and EPF arrows. Students demonstrated minimal errors when drawing the EPF arrows and scored higher on familiar and unfamiliar reactions following the new curriculum, which suggests students found the EPF arrows meaningful. The following think-aloud interview study better captured student interpretations of the EPF arrows to determine what features students found relevant and whether the students who could explain a conceptual understanding of the EPF arrows could express a deeper understanding. The think-aloud interviews found that students do place meaning into organic chemistry representations as students were thinking about how to draw the EPF arrows based on prior knowledge. The data from the two previous studies were collected near the end of the course when students had a significant amount of experience, while students’ initial interpretations of the EPF arrows are needed. The primary focus of this thesis is to understand how students initially interpret the electron-pushing formalism arrows and look further into previous findings, which include electron movement, bond-forming and breaking processes, mapping, charges, stepwise reasoning, and transplanting electrons. Twelve students were recruited from Organic Chemistry I and interviewed over three weeks after being taught the electron-pushing formalism. The interviews were conducted using a think-aloud procedure to capture students’ thoughts, and each interview lasted approximately 1 hour. The instrument consisted of six organic chemistry questions, specifically chosen, as students would not encounter them in the class and would have to interpret the representations. The transcripts were analyzed with respect to the previous studies' findings and compared among participants to explore students’ interpretations and use of the EPF arrows. The findings from this study suggest participants found the EPF arrows meaningful because participants interpreted the representations as electron-movement, bond-forming, and bond-breaking processes which contrasts some prior research that reported students do not find the EPF arrows meaningful (Bhattacharyya and Bodner, 2005; Graulich, 2015). Participants connected the EPF arrows to electron movement, bond-forming, and bond-breaking processes. Participants compared surface features to determine how to draw the EPF arrows. Participants’ visualization and how they approached the reactions differed. Participants’ visualizations of the organic chemistry reaction were divided between a stepwise or concerted visualization. Most participants approached the EPF arrows stepwise as a problem-solving tool as it was easier for them to understand. Participants correctly interpreted most bond-breaking EPF arrows, but some participants relocated the electron pair onto a different atom instead of forming a bond. Participants mainly mapped the carbon atoms with numeric labels and found implicit atom-type questions challenging. Participants interpreted charges as an important surface feature and used charges to help them solve the question. Participants viewed charges as a reactive location where bonds break and form and compared the number of charges between reactants and products to check whether their answers were correct. The results suggest the participants in the study found the EPF arrows and made meaningful connections at the submicroscopic level with minimal experience. Mastering the EPF arrows at the beginning of the course appears beneficial to student learning because participants interpreted the EPF arrows as a meaningful representation suggesting that the EPF arrows are less of a barrier when learning and mastering organic chemistry, under the University Of Ottawa’s organic chemistry curriculum as intended. Since the EPF arrows are less of a barrier, students can focus on other organic chemistry concepts and can be more successful which is seen in the first exam analysis where minimal errors were seen. The first exam analysis observed minor pentavalent atoms and errors with the EPF arrows (Flynn and Featherstone, 2017). The following interview study found students described mapping, charges, stepwise, and chemistry reasoning when discussing electron movement (Galloway et al., 2017). The findings from this work demonstrated the EPF arrows as a representation are meaningful to participants as they interpreted the EPF arrows after being recently taught. Similar findings at a different institution using a revised curriculum that focuses on the EPF at the beginning of the course found students were more likely to use the EPF arrows and were more likely to provide the correct answer than their counterparts (Crandell et al., 2018; Houchlei et al., 2021). Research at institutions adopting the functional group curriculum reported that students did not find the EPF meaningful (Bhattacharyya and Bodner, 2005; Ferguson and Bodner, 2008; Grove, Cooper, and Rush, 2012). The findings suggest that the time spent mastering the EPF arrows at the beginning of the course is beneficial when learning organic chemistry because the symbols are less likely to be a hindrance through misinterpretation, and students can focus on mastering organic chemistry concepts. Implications for teaching and learning include providing clarity on interpreting the EPF arrows and using the transplanting processes to demonstrate other chemical possibilities. Participants demonstrated comparing reactants and products when problem-solving. When students face difficulty, they should compare the products of chemical processes (bond-forming, bond-breaking, or electrons moving). The correct process has the EPF arrow starting from electrons and point to an atom or bond, maintains the conservation of atoms, and electrons stay with one of the originating atoms. The other processes will not follow one of the above principles, thus making them illogical. Future work could further explore if students interpret the EPF arrows as a whole or if they interpret the arrowhead and arrow tail. Why do some students face difficulty keeping electrons on an originating atom? Why do some students face difficulty conserving atoms, electrons, and charges throughout a reaction? Whether the findings are generalizable by expanding the sample size. In the context of the new curriculum, it appears students' have acquired a better understanding of the EPF. The results are promising because participants with minimal experience interpreted the EPF arrows and found them meaningful as a symbolic representation aligned with the curriculum's intentions.

<p> Two-dimensional C-H chemical shift correlation spectroscopy provides a large amount of information in a two dimensional matrix. Many variations of these experiments have been in an effort to enhance the information content of these experiments. Decoupling of multiplet signals is one method used to increase the sensitivity of an NMR experiment. Simple broadband decoupling in ω2 is done by irradiating the correlated channel during acquisition. Decoupling in ω1 must be done using less direct methods, one of which is to use bilinear rotation decoupling. The traditional description of the effect that a BIRD pulse has on the spin systems is based on a simple AX system which is at equilibrium at the beginning of the pulse, which does not apply in many real systems.</p> <p> This study uses the Superspin formalism to show in more detail the behaviour of more complex spin systems during the BIRD sequence, and the effect of varying parameters within the BIRD sequence. This treatment involved the derivation of complete spherical tensor descriptions of AX, AX2, and AX3 spin systems. This allowed the derivation of a mathematical description of an INEPT style pulse sequence, where the refocussing pulse in INEPT was replaced with the BIRD sequence. The derivation of the general evolution transformations of the spherical tensors in Liouville space also allowed the theoretical treatment to be done in a single basis, where earlier implementations of the Superspin formalism converted between a spherical tensor basis for the treatment of pulses and a Hamiltonian basis for the treatment of delays. This theoretical treatment allows the derivation of a functional form for the dependence of the carbon signal intensity on the variation of the interpulse delay in the BIRD sequence.</p> <p> This formalism was also used to analyze the occurrence of artifacts in two dimensional heteronuclear shift correlation spectra, due to strong coupling between methylene protons. These artifacts were studied in experiments that attempt broadband homonuclear decoupling in ω1 through the use of constant evolution time between the initial excitation pulse and polarization transfer. Two experiments were analyzed, the COLOC experiment and the HETRES experiment. The superspin formalism was used to deduce a functional form for the intensity of the artifact as a function of the strength of the coupling between the methylene protons.</p> / Thesis / Master of Science (MSc)

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Orientador: Bruto Max Pimentel Escobar / Resumo: Neste trabalho apresentamos o formalismo Hamiltoniano de Dirac para sistemas singulares, analisando inclusive a construção do gerador de transformações de gauge. A seguir discutimos brevemente a generalização, já conhecida, desse formalismo para o caso de Lagrangeanos singulares de segunda ordem fazendo também uma análise da estrutura de vínculos presente em tais teorias. Desenvolvemos então o formalismo de Hamilton-Jacobi para sistemas singulares fazendo sua generalização para Lagrangeanos de segunda ordem. Por último, ambos formalismos são aplicados à Eletrodinâmica de Podols y e os resultados obtidos são comparados. / Abstract: In this work we study Dirac's Hamiltonian formulation for singular systems including the construction of the gauge transformations generator. Next we briefy discuss the generalization, already developed, of this formalism for singular second order La grangians. Besides that we also make an anlysis of the constrains structure present in such theories. Then we develop the Hamilton-Jacobi formalism for singular systems making its generalization for the case of second order Lagrangians. Finally, both formalisms are applied to Podols y's eletrodynamics and the obtained results are comparad. / Mestre

This article introduces the concept of System Art and lays a foundation for creating a cohesive and functional framework for artistic interactive system analysis. The paper applies Russian Formalist theory for that purpose, explores the existing literature that covers such topics as Art Games and Videogame Formalism, and identifies the gaps in the currently existing works that should be addressed before building such framework: the lack of clearly defined interactive system elements, the lack of artistic device categorization, the lack of understanding of the role meaning plays in an artistic piece, and the lack of understanding different types of Defamiliarization effect – a notion proposed by Russian Formalists (Shklovsky, 2015) and adapted to games by Mitchell (2016). This article builds a foundation for creating an artistic system-oriented analysis theory, that would in turn be able to become a part of a bigger framework for studying digital games as an interdisciplinary form of artistic expression.

Cette thèse se propose d'explorer les mérites d'une famille d'approches de simulation quantique ab initio, les théories de perturbation à N-corps, pour l'exploration des propriétés électroniques et optiques de systèmes organiques. Nous avons étudié en particulier l'approximation dite de GW et l'équation de Bethe-Salpeter, très largement utilisées dès les années soixante pour les semiconducteurs de volume, mais dont l'utilisation pour les systèmes organiques moléculaires est très limitée. L'étude de quelques cas d'intérêt pour le photovoltaïque organique, et en particulier de petites molécules pour lesquelles sont disponibles des données expérimentales ou des résultats issus d'approches de chimie quantique, nous ont permis de valider ces approches issues de la physique du solide.Ce doctorat s'inscrit dans le cadre du développement d'un outil de simulation quantique spécifique (le projet FIESTA) dont l'objectif est de combiner les formalismes GW et Bethe-Salpeter avec les techniques de la chimie quantique, c'est-à-dire en particulier l'utilisation de bases localisées analytiques (bases gaussiennes) et des approches de type «résolution de l'identité» pour le traitement des intégrales Coulombiennes. Ce code est aujourd'hui massivement parallélisé, permettant, au delà des études de validation présentées dans ce travail de thèse, l'étude de systèmes complexes comprenant plusieurs centaines d'atomes. En cours de développement, l'incorporation d'approches hybrides combinant mécanique quantique et écrantage à longue portée par des approches modèles de milieu polarisable m'a permis d'une part de me familiariser avec le code et le développement méthodologique, et permet d'autre part d'envisager l'étude de systèmes réalistes en couplage avec leur environnement.Le manuscrit s‘ouvre sur une introduction au photovoltaïque organique afin de mettre en lumière les questionnements spécifiques qui requièrent le développement de nouveaux outils théoriques à la fois fiables en terme de précision et suffisamment efficaces pour traiter des systèmes de grande taille. Le premier chapitre est d'ordre méthodologique et rappelle les fondements des techniques ab initio de type champ-moyen (Hartree, Hartree-Fock et théorie de la fonctionnelle de la densité). En partant des principes de la photoémission, les théories de perturbation à N-corps et la notion de quasi-particule sont ensuite introduites, conduisant aux équations de Hedin et aux approximations GW et COHSEX. De même, à partir de la compréhension d'une expérience d'optique, le traitement des interactions électron-trou est présenté, menant à l'équation de Bethe-Salpeter. Le chapitre 2 introduit brièvement les spécificités techniques liées à l'implémentation des formalismes GW et Bethe-Salpeter. Les propriétés analytiques des bases gaussiennes et les principes mathématiques derrière les techniques de type «résolution de l'identité» et «déformation de contour», sont brièvement décrites. Le troisième chapitre présente les résultats scientifiques obtenus durant cette thèse. Le cas paradigmatique d'un polypeptide model nous permettra de discuter des spécificités de l'approche GW appliquée à des systèmes moléculaires afin d'obtenir des énergies de quasiparticule de bonne qualité. De même, l'utilisation de l'équation de Bethe-Salpeter pour l'obtention du spectre optique de ce système sera présentée, ainsi que le cas d'une famille de colorants d'importance pour les cellules de Graetzel (les coumarines). Finalement, nous explorons dans le cas du fullerène C60 et du graphène le calcul des termes de couplage électron-phonon dans le cadre de l'approche GW, c'est-à-dire au delà des approches standards de type théorie de la fonctionnelle de la densité. Notre étude vise à vérifier si une approximation statique et à écrantage constant au premier ordre permet de garder la qualité des résultats GW pour un coût numérique réduit. Après la conclusion, les appendices donnent le détail de certaines dérivations. / The present thesis aims at exploring the properties and merits of the ab initio Green's function many-body perturbation theory (MBPT) GW and Bethe-Salpeter formalisms, in order to provide a well-grounded and accurate description of the electronic and optical properties of condensed matter systems. While these approaches have been developed for extended inorganic semiconductors and extensively tested on this class of systems since the 60 s, the present work wants to assess their quality for gas phase organic molecules, where systematic studies still remain scarce. By means of small isolated study case molecules, we want to progress in the development of a theoretical framework, allowing an accurate description of complex organic systems of interest for organic photovoltaic devices. This represents the main motivation of this scientific project and we profit here from the wealth of experimental or high-level quantum chemistry reference data, which is available for these small, but paradigmatic study cases.This doctoral thesis came along with the development of a specific tool, the FIESTA package, which is a Gaussian basis implementation of the GW and Bethe-Salpeter formalisms applying resolution of the identity techniques with auxiliary bases and a contour deformation approach to dynamical correlations. Initially conceived as a serial GW code, with limited basis sets and functionalities, the code is now massively parallel and includes the Bethe-Salpeter formalism. The capacity to perform calculations on several hundreds of atoms to moderate costs clearly paves the way to enlarge our studies from simple model molecules to more realistic organic systems. An ongoing project related to the development of discrete polarizable models accounting for the molecular environment allowed me further to become more familiar with the actual implementation and code structure.The manuscript at hand is organized as follows. In an introductory chapter, we briefly present the basic mechanisms characterizing organic solar cells, accentuating the properties which seek for an accurate theoretical description in order to provide some insight into the factors determining solar cell efficiencies. The first chapter of the main part is methodological, including a discussion of the principle features and approximations behind standard mean-field techniques (Hartree, Hartree-Fock, density functional theory). Starting from a description of photoemission experiments, the MBPT and quasiparticle ideas are introduced, leading to the so-called Hedin's equations, the GW method and the COHSEX approach. In order to properly describe optical experiments, electron-hole interactions are included on top of the description of inter-electronic correlations. In this context, the Bethe-Salpeter formalism is introduced, along with an excursus on time-dependent density functional theory. Chapter 2 briefly presents the technical specifications of the GW and Bethe-Salpeter implementation in the FIESTA package. The properties of Gaussian basis sets, the ideas behind the resolution of the identity techniques and finally the contour deformation approach to dynamical correlations are discussed. The third chapter deals with the results obtained during this doctoral thesis. On the electronic structure level, a recent study on a paradigmatic dipeptide molecule will be presented. Further, also its optical properties will be explored, together with an in-depth discussion of charge-transfer excitations in a family of coumarin molecules. Finally, by means of the Buckminster fullerene C60 and the two-dimensional semi-metal graphene, we will analyze the reliability of two many-body formalisms, the so-called static COHSEX and constant-screening approximation, for an efficient calculation of electron-phonon interactions in organic systems at the MBPT level. After a short conclusion, the Appendix containing details and derivations of the formalisms presented before closes this work.

This thesis reviews the method of Mafra, Schlotterer, and Stieberger (2011) for computing the full colour ordered N-point open superstring amplitude using the Pure Spinor formalism. We introduce relevant elements of super Yang-Mills theory and examine the basics of the Pure Spinor formalism, with a focus on tools for amplitude computation. We then define a series of objects with increasingly useful BRST transformation properties, which greatly simplify the calculations, and show how these properties can be determined using a diagrammatic method. Finally, we use the explicit four- and five-point amplitude computations as stepping stones to compute the general N-point amplitude, which factors into a set of kinematic integrals multiplying SYM subamplitudes.

Fundamental studies on thermodynamic properties of vanadium-containing oxides systems are essential to understand practical vanadium metallurgical process. The CALPHAD technique is here applied to the thermodynamic modelling of the V-O, Ca-V-O and Ti-V-O systems. The compound energy formalism is used for all the solution phases. All optimization processes and calculations are performed using the Thermo-Calc software package. The present work attempts to develop a self-consistent thermodynamic database of all phases in the studied systems. The obtained datasets can be used to calculate thermodynamic properties, stable as well as metastable phase equilibria and driving forces for oxidation etc. Steelmaking slag is an important secondary source for vanadium extraction. The phase relationships and vanadium distribution in the CaO-SiO2-MgO-V2O3-Al2O3 synthetic slags, whose compositions were chosen based on the relevance to the steel producers, are also studied. Phase equilibria in the temperature range of 1773 to 1823 K at oxygen partial pressure of 10-10 bar and 0.21 bar were characterized. An investigation of the volatilization of vanadium oxide was also carried out in the present work. Isothermal evaporation of vanadium pentoxide in the temperature range between 1723 and 1873 K was investigated by Thermogravimetric Analysis under different oxygen partial pressures, viz. oxygen, air or CO2. The Arrhenius activation energy for the evaporation reaction in various atmospheres was calculated from the experimental results. A mathematical model was developed to describe the kinetics of the evaporation process. Evaporation coefficients and enthalpies in various atmospheres were also estimated. The present results may have some implications in recovering vanadium from different vanadium-bearing sources. / <p>QC 20161202</p>

This thesis presents a development of classical canonical formalism and the usual transition schema to quantum dynamics. The question of transition from relativistic mechanics to relativistic quantum dynamics is answered by developing a homogeneous formalism which is relativistically invariant. Using this formalism the Klein-Gordon equation is derived as the relativistic analog of the Schroedinger equation. Using this formalism further, a method of generating other relativistic equations (with spin) is presented.