More and more computer applications are using three-dimensional models for a variety of uses (e.g. CAD, graphics, recognition). A major bottleneck is the acquisition of these models. The easiest method for designing the models is to build them directly from images of the object being modelled. This paper describes the design of a system, MOLASYS (for MOdeL Acquisition SYStem), that allows the user to build object models interactively from underlying images. This would not only be easier for the user, but also more accurate as the models will be built directly satisfying the dimensions, shape, and other constraints present in the images. The object models are constructed by constraining model points and edges to match points in the image objects. The constraints are defined by the user and expressed using a Jacobian matrix of partial derivatives of the errors with respect to a set of camera and model parameters. MOLASYS then uses Newton's method to solve for corrections to the parameters that will reduce the errors specified in the constraints to zero. Thus the user describes how the system will change, and the program determines the best way to accomplish the desired changes. The above techniques, implemented in MOLASYS, have resulted in an intuitive and flexible tool for the interactive creation of three-dimensional models. / Science, Faculty of / Computer Science, Department of / Graduate

The three-dimensional perovskites are known for their wide range of interesting properties including spectral tunability, charge carrier mobility, solution-based synthesis and many others. Such properties make them good candidates for photovoltaics and photodetectors. Low-dimensional perovskites, on the other hand, are good as light emitters due to the quantum confinement originating from their nanoparticle size. Another class of low-dimensional perovskites, also called low-dimensional-networked perovskites (L-DN), is recently reemerging. Those interesting materials combine the advantages of the nanocrystals and the stability of the bulk. For example, zero-dimensional-networked perovskite (0-DN), a special class of perovskites and the focus of this work, consists of building blocks of isolated lead-halide octahedra that could be synthesized into mm-size single crystal without losing their confinement. This thesis focuses on the synthesis and investigation of the optical properties of the 0-DN perovskites through experimental, theoretical and computational tools. The recent discovery of the retrograde solubility of the perovskites family (ABX3), the basis of the inverse temperature crystallization (ITC), inspired the reinvestigation of the low-dimensional-networked perovskites. The results of the optical characterization showed that the absorption and the corresponding PL spectra were successfully tuned to cover the visible spectrum from 410 nm for Cs4PbCl6, to 520 nm and 700 m for Cs4PbBr6 and Cs4PbI6, respectively. Interestingly, the exciton binding energies (Eb) of the 0-DNs were found to be in the order of few hundred meV(s), at least five times larger than their three-dimensional counterpart. Such high Eb is coupled with a few nanoseconds lifetime and ultimately yielded a high photoluminesce quantum yield (PLQY). In fact, the PLQY of Cs4PbBr6 powder showed a record of 45%, setting a new benchmark for solid-state luminescent perovskites. Computational methods were used to calculate the bandgap and study the corresponding excitonic behavior. However, the unexpected mismatch between the calculated and experimental bandgaps questions the origin of the high luminescence, which to date, remains an area of scientific debate that needs further study. Until then, the high PLQY, together with the spectral tunability, insensitivity to particle size and stability all offer a new avenue for more sustainability in light-emitting materials

archives@tulane.edu / In this work, five algorithms of negative dimensional integration (NDIM) are compared in several examples of Feynman diagram calculations, and the resulting solutions are compared. The methods used are the Ricotta method without parametrization, the Ricotta method with Schwinger parametrization, the Suzuki method, the Anastasiou method, and the method of brackets. It is found that for one-loop diagrams, the method of brackets gives the same solution as the other methods, but without requiring analytic continuation of the gamma factors in the solution. For multi-loop diagrams, the method of brackets gives solutions in a simpler form than the other methods, and often gives fewer possible solutions as well. In addition to its use in the evaluation of Feynman diagrams, the method of brackets is also useful when extended to the evaluation of definite integrals over the positive real numbers. This extended method of brackets is applied to several examples of definite integrals, and the five NDIM methods are also used to evaluate these examples when possible. In particular, it is shown that the method of brackets is the only method of NDIM which may be extended to the evaluation of a large class of definite integrals over the positive real numbers. / 1 / Kristina E. VanDusen

In this study, topology optimisation for heat-conducting paths in a three-dimensional domain was investigated. The governing equations for the temperature distribution were solved using the finite volume method, the sensitivities of the objective function (average temperature) were solved using the adjoint method, and finally, the optimal architecture was found with the method of moving asymptotes (MMA) using a self programmed code. A two-dimensional domain was evaluated first as a validation for the code and to compare with other papers before considering a three-dimensional cubic domain. For a partial Dirichlet boundary, it was found that the converged architecture in three dimensions closely resembled the converged architectures from two dimensions, with the main branches extending to the outer corners of the domain. However, the partial Dirichlet boundary condition was not realistic, and to represent a more realistic case, a full Dirichlet boundary was also considered. In order to investigate a full Dirichlet boundary condition, the domain had to be supplied with an initial base for the architecture to allow variation in the sensitivities. It was found that the width and height of this base had a significant effect on the maximum temperature. A height of 0.04 with a base width of 0.24 proved to be the most effective, since this small base gave the MMA enough freedom to generate a tree structure. It was first assumed that this base should be in the centre of the bottom boundary and this was later proved. The results showed again that the maximum temperature decreased with an increase in the conductivity ratio or volume constraint. The architectures were similar to the partial Dirichlet boundary, again with the main branches extending to the outer corners of the domain. The main branches were thinner compared with the partial Dirichlet boundary and fewer secondary branches were observed. It was concluded that a full Dirichlet boundary could be solved using topology optimisation, if the boundary was supplied with an initial base. With the successful implementation of the full Dirichlet boundary with one initial base, multiple bases were investigated. First, two bases were used and it was assumed that the optimal placement for these bases was in the centre of each respective half of the bottom boundary, which was later confirmed. The optimal width and height of 0.24 and 0.04 respectively were again optimal for each specific base. The same procedure was followed for four bases and it was assumed that the optimal placement was in the centre of each respective quadrant of the bottom boundary, which was also later confirmed. The optimal width and height of 0.12 and 0.04 respectively were found for this case. With this established, optimisation runs for different conductivity ratios and volume constraints were completed for two and four bases. It was found that two bases offered increased performance in terms of the maximum temperature compared with one base. An increase in performance was also observed when using four bases compared with two bases. A maximum of 20.4% decrease in the maximum temperature was observed when comparing four bases with one. Keywords: topology, optimisation, conduction, three-dimensional / Dissertation (MSc)--University of Pretoria, 2014. / gm2014 / Mechanical and Aeronautical Engineering / Unrestricted

abstract: The increasing pervasiveness of infections caused by multidrug-resistant bacteria (MDR) is a major global health issue that has been further exacerbated by the dearth of antibiotics developed over the past 40 years. Drug-resistant bacteria have led to significant morbidity and mortality, and ever-increasing antibiotic resistance threatens to reverse many of the medical advances enabled by antibiotics over the last 40 years. The traditional strategy for combating these superbugs involves the development of new antibiotics. Yet, only two new classes of antibiotics have been introduced to the clinic over the past two decades, and both failed to combat broad spectrum gram-negative bacteria. This situation demands alternative strategies to combat drug-resistant superbugs. Herein, these dissertation reports the development of potent antibacterials based on biomolecule-encapsulated two-dimensional inorganic materials, which combat multidrug-resistant bacteria using alternative mechanisms of strong physical interactions with bacterial cell membrane. These systems successfully eliminate all members of the ‘Superbugs’ set of pathogenic bacteria, which are known for developing antibiotic resistance, providing an alternative to the limited ‘one bug-one drug’ approach that is conventionally used. Furthermore, these systems demonstrate a multimodal antibacterial killing mechanism that induces outer membrane destabilization, unregulated ion movement across the membranes, induction of oxidative stress, and finally apoptotic-like cell death. In addition, a peptide-encapsulation of the two-dimensional material successfully eliminated biofilms and persisters at micromolar concentrations. Overall, these novel systems have great potential as next-generation antimicrobial agents for eradication of broad spectrum multidrug-resistant bacteria. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2019

Indiana University-Purdue University Indianapolis (IUPUI) / Background: The advancement of three-dimensional visualization technology provides exciting new opportunities in medical education, including new methods for teaching complex anatomical relationships and promising tools for the training of postgraduate physicians. Information on how faculty use three-dimensional visualization technology for anatomy education is essential for informed discussions surrounding their effectiveness as a teaching tool and use in the medical curriculum, yet the current literature lacks necessary contextual details on how faculty integrate these technologies into actual medical curricula. Methods: Fifteen medical educators from North American medical schools and teaching hospitals completed semi-structured interviews and discussed how they use three-dimensional visualization technology for teaching in preclinical courses, clinical clerkships, and postgraduate programs. Transcripts were analyzed using the constant comparative method and resulting themes were used to inform the creation of a questionnaire. Results: The resulting themes of analysis were organized according to a curricular framework that describes how faculty use these technologies as an instructional resource and how this use is related to the purposes, content, sequence, instructional processes and evaluation of medical curricula. The results demonstrate how three-dimensional visualization technology is being is implemented in a variety of ways in the curriculum and revealed numerous similarities of use across the levels of medical education. Analyses revealed minimal use of three-dimensional visualization technology for assessment and indicated faculty face significant challenges in designing such assessment. Conclusions: Results suggest continuing assessment of the effectiveness of these technologies as a teaching tool needs to encompass broader aspects of use, such as those described in this study. Additionally, results showing similarities of use across levels suggest that educators and administrators should consider how threedimensional visualization technology can be thoughtfully integrated to address the changing needs of learners as they progress through medical education. Findings also suggest that administrators who want to support the integration of three-dimensional visualization technology into the curriculum need to provide adequate support and training to help faculty overcome time limitations and difficulties designing assessment methods.

We employ a four-band continuum model to study the transport and confinement in an n-p-n junction in bilayer chiral borophene for both the identical- and oppositechirality configurations. The conditions for transport and confinement are elucidated in terms of the pseudospin. We study the transmission and reflection probabilities, conductances, and bound states. We demonstrate the existence of topological states in a domain wall between domains of opposite-chirality bilayer chiral borophene with reversed layer stacking. We find that changing the interlayer bias modifies the conductance of the identical-chirality configuration but not that of the opposite-chirality configuration, and that it induces a layer localization of the bound and topological states. Our findings suggest paths towards utilization of the layer degree of freedom in bilayer chiral borophene in future electronic devices.

In den letzten zwei Jahrzehnten hat sich die kohärente mehrdimensionale Femtosekunden- Spektroskopie zu einem leistungsstarken und vielseitigen Instrument zur Untersuchung der chemischen Dynamik einer Vielzahl von Quantensystemen entwickelt. Die Kombination von transienten Informationen, die der Anrege-Abrage-Spektroskopie entsprechen, mit Informationen zur Kopplung zwischen energetischen Zuständen und der Systemumgebung ermöglicht einen umfassenden Einblick in atomare und molekulare Eigenschaften. Viele experimentelle 2D-Aufbauten verwenden den kohärenzdetektierten Ansatz, bei dem nichtlineare Systemantworten als kohärente elektrische Felder emittiert und räumlich getrennt von den Anregungspulsen detektiert werden. Als Alternative zu diesem experimentell anspruchsvollen Ansatz wurde die populationsbasierte 2D-Spektroskopie etabliert. Hier wird die kohärente Information in den Phasen einer kollinearen Anregungspulsfolge codiert und aus inkohärenten Signalen wie Fluoreszenz über Phase Cycling extrahiert. Grundsätzlich kann durch die Verwendung von Fluoreszenz als Observable eine Sensitivität bis zum Einzelmolekülniveau erreicht werden. Ziel dieser Arbeit war die Realisierung eines pulsformergestützten vollständig kollinearen fluoreszenzdetektierten 2D-Aufbaus und die Durchführung von Proof-of- Principle-Experimenten in der Flüssigphase. Dieser inhärent phasenstabile und kompakte Aufbau wurde in Kapitel 3 vorgestellt. Der verwendete Pulsformer ermöglicht eine Amplituden- und Phasenmodulation von Schuss zu Schuss. Zwei verschiedene Arten von Weißlichtquellen wurden angewendet und hinsichtlich ihrer jeweiligen Vorteile für die 2D-Fluoreszenzspektroskopie bewertet. Eine Vielzahl von Artefaktquellen, die mit dem vorliegenden Aufbau auftreten können, wurden diskutiert und Korrekturschemata und Anweisungen zur Vermeidung dieser Artefakte bereitgestellt. In Kapitel 4 wurde der Aufbau anhand einer Vierpulssequenz mit Cresylviolett in Ethanol demonstriert. Es wurde ein detailliertes Datenerfassungs- und Datenanalyseverfahren vorgestellt, bei dem Phase Cycling zur Extraktion der nichtlinearen Beiträge verwendet wird. Abhängig vom Phase Cycling-Schema ist es möglich, alle nichtlinearen Beiträge in einer einzigen Messung aufzudecken. Literaturbekannte Oszillationen von Cresylviolett während der Populationszeit konnten reproduziert werden. Aufgrund der Messung in einer Umgebung im Rotating Frame und einer 1 kHz Schuss-zu-Schuss Pulsinkrementierung war es möglich, ein 2D-Spektrum für eine Populationszeit in 6 s zu erhalten. Eine Fehlerevaluierung hat gezeigt, dass eine zehnfache Mittelwertbildung (1 min) ausreicht, um eine mittlere quadratische Abweichung von < 0:05 gegen� uber einer 400-fachen Mittelwertbildung zu erhalten, was beweist, dass das verwendete Messschema gut geeignet ist. Die Realisierung des ersten experimentellen fluoreszenzdetektierten 2Q-2D-Experiments und der erste experimentelle Zugang zum theoretisch vorhergesagten 1Q-2Q-Beitrag wurden in Kapitel 5 vorgestellt. Zu diesem Zweck wurde eine Dreipulssequenz auf Cresylviolett in Ethanol angewendet und die experimentellen Ergebnisse wurden mit Simulationen eines einfachen Sechs-Level-Systems verglichen. Im Gegensatz zur kohärenzdetektierten 2Q-2D-Spektroskopie sind bei dem vorgestellten Aufbau keine nichtresonanten Lösungsmittelsignale und Streuungsbeiträge sichtbar und es ist kein zusätzliches Phasing-Verfahren erforderlich. Durch eine Kombination aus Experimenten und systematischen Simulationen wurden Informationen über die Relaxation der Lösungsmittelhülle und die Korrelationsenergie gewonnen. Auf der Basis von Simulationen wurden Effekte der Pfadauslöschung diskutiert, die darauf schließen lassen, dass die 1Q-2Q-2D-Spektroskopie möglicherweise die quantitative Analyse für molekulare Systeme erleichtert, die eine starke nichtstrahlende Relaxation aus höheren elektronischen Zuständen aufweisen. Zusammenfassend ist es mit der vorgestellten Methode möglich, alle nichtlinearen Beiträge mit einer schnellen Datenaufnahme und einem einfach einzurichtenden Aufbau zu erfassen. Die gezeigten Proof-of-Principle-Experimente stellen eine Erweiterung der 2D-Spektroskopie-Werkzeugpalette dar und bieten eine fundierte Grundlage für zukünftige Anwendungen wie mehrdimensionale Spektroskopie, mehrfarbige 2D-Spektroskopie oder die Kombination von simultanen Flüssig- und Gasphasen-2D-Experimenten. / In the last two decades, coherent multidimensional femtosecond spectroscopy has become a powerful and versatile tool to investigate chemical dynamics of a broad variety of quantum systems. The combination of transient information, equivalent to pumpprobe spectroscopy, with information about coupling between energetic states and the system environment allows an extensive insight into atomic and molecular properties. Many experimental 2D setups employ the coherence-detected approach, where nonlinear system responses are emitted as coherent electric _elds which are detected after spatial separation from the excitation pulses. As an alternative to this experimentally demanding approach, population-based 2D spectroscopy has been established. Here, the coherent information is encoded in the phases of a collinear excitation-pulse train and extracted from incoherent signals like uorescence via phase cycling. In principle, the use of uorescence as observable can boost the sensitivity down to the single-molecule level. The aim of this work was the realization of a pulse-shaper assisted fully collinear uorescence-detected 2D setup and the conducting of proof-of-principle experiments in the liquid phase. This inherently phase-stable and compact setup has been presented in chapter 3, with the utilized pulse shaper granting amplitude and phase modulation on a shot-to-shot basis. Two di_erent types of white-light sources have been applied and evaluated with regard to their respective advantages for 2D uorescence spectroscopy. A variety of artifact sources that can occur with the present setup have been discussed, and correction schemes and instructions for avoiding these artifacts have been provided. In chapter 4, the setup has been demonstrated by employing a four-pulse sequence on cresyl violet in ethanol. A detailed data-acquisition and data-analysis procedure has been presented, where phase cycling is used for extraction of the nonlinear contributions. Depending on the phase-cycling scheme, it is possible to recover all nonlinear contributions in a single measurement. Well-known quantum-beating behavior of cresyl violet during the population time could be reproduced. Due to measuring in a rotating-frame environment and 1 kHz shot-to-shot pulse incrementation, it was possible to obtain a 2D spectrum for one population time in 6 s. Via error evaluation it has been shown that 10_ averaging (1 min) is su_cient to obtain a root-mean-square error of < 0:05 compared to 400_ averaging, proving that the utilized acquisition scheme is well suited. The realization of the _rst experimental uorescence-detected 2Q 2D experiment and the _rst experimental access to the theoretically predicted 1Q-2Q contribution

The study of three-dimensional percolation paths through materials is important in its contribution to understanding defect sensitive properties of materials. This work shows the importance of grain boundary character in modeling defect sensitive boundaries. Also presented are trends of percolation of sensitized grain boundaries in 304 stainless steel (304SS). Of particular interest is how open paths form in a three-dimensional model created through serial sectioning. Evidence is presented that triple or quadruple points that contain typically two boundaries with special character that intersect the percolation path break up the path. Some grains with no known special qualities (i.e., CSL) have observable special behavior.

MacMahon's Master Theorem is an important result in the theory of algebraic combinatorics. It gives a precise connection between coefficients of certain power series defined by linear relations. We give a complete proof of MacMahon's Master Theorem based on MacMahon's original 1960 proof. We also study a specific infinite dimensional matrix inverse due to C. Krattenthaler.