Underlying all my work is a tension between the painter and the builder. I love to paint. I love the lie inherent in paint: that it can make a picture plane masquerade as light, space, or recognizable place with recognizable figuration. I love how paint—particularly oil paint—can rest in gloppy piles, how it can drip, splatter, spread, or how it can squeeze out of paint tubes in long, stringy beads. I love how paint changes how we see an interior space or a three-dimensional form. Yet I also love building things—usually out of wood—measuring and cutting, fastening things together—all to serve a function or solve a problem. In every studio I have had, there has always been an arms race between my fine art supplies and my tools. My work during my three years at the Department of Art and Art History at the University of Texas at Austin has undergone some dramatic changes. In large part this paper will elaborate and evaluate the trajectory of these changes. Yet, in spite of these changes, the competing impulses to paint and to build have remained constant. This report will leave unanswered the question whether these two impulses can or should be reconciled, kept separate, or whether one should be sacrificed in favor of the other. The artist writing this report does not know at this point in time, and cannot hope to answer this question without making more work in a new context. This report instead will reveal how I arrived at the work I am making at the time of writing this report, and why I regard this new body of work as being about the “paint gap.” I define the “paint gap” as the distinction—mild or strong—between paint itself and the object or surface upon which paint is applied. / text

O σκοπός της εργασίας αυτής ήταν η σύνθεση νέων αστεροειδών τριπολυμερών, τύπου An(B-C)n διαφόρων μοριακών δομών, με την τεχνική του «ζωντανού» ανιονικού πολυμερισμού. Αναπτύχθηκε μια μεθοδολογία τεσσάρων διαδοχικών σταδίων σε αντίδραση διαλείποντος έργου η οποία δίνει προϊόντα καθορισμένης μοριακής αρχιτεκτονικής. Η μέθοδος αυτή είναι επέκταση της μεθόδου in-out που χρησιμοποιήθηκε για την σύνθεση ετεροκλαδικών συμπολυμερών αστεροειδών τύπου ΑnBn. Τα νέα αστεροειδή τριπολυμερή Αn(B-C)n αποτελούνται από ένα πυρήνα διασταυρομένων μονομερών από τον οποίο εξέρχονται δύο ειδών κλάδοι θεωρητικά ίσου αριθμού, ήτοι κλάδοι ομοπολυμερούς Α και κλάδοι δι-συσταδικού συμπολυμερούς (B-C). Για το σκοπό αυτό χρησιμοποιήθηκε μια ποικιλία μονομερών και παραγόντων συνένωσης προκειμένου να επιτύχουμε το επιθυμητό αποτέλεσμα. Χρησιμοποιήθηκαν διφορετικοί πυρήνες των αστεροειδών τόσο στη φύση (διβίνυλοβενζόλιο, διμεθακρυλικός αιθυλενο-γλυκολεστέρας) όσο και στις διαστάσεις (μίγμα διβίνυλοβενζολίου/στυρενίου) προκειμένου να μελετηθεί η επίδραση που φέρουν. Η μεθοδολογία που χρησιμοποιήθηκε δίνει τη δυνατότητα του σταδιακού χαρακτηρισμού των προϊόντων ο οποίος ήταν ουσιώδης για τον τελικό χαρακτηρισμό των τριπολυμερών. Για το μοριακό χαρακτηρισμό πρόδρομων και τελικών πολυμερών χρησιμοποιήθηκαν οι τεχνικές της χρωματογραφίας αποκλεισμού μεγεθών, της στατικής σκέδασης φωτός και η φασματοσκοπία του πυρηνικού μαγνητικού συντονισμού (1H-NMR). Επιπλέον για λόγους σύγκρισης ιδιοτήτων μεταξύ γραμμικών και αστεροειδών, συντέθηκαν γραμμικά ABC τριπολυμερή χρησιμοποιώντας την μέθοδο της διαδοχικής προσθήκης. Τα τελικά πολυμερή καθαρίστηκαν από τυχόν προσμίξεις με την τεχνική της soxhlet και χρησιμοποιώντας ως διαλύτη κυκλοεξάνιο. Μελετήθηκαν οι μηχανικές ιδιότητες των ετεροκλαδικών αστεροειδών συμπολυμερών σε σύγκριση με τα αντίστοιχα γραμμικά τριπολυμερή, με σκοπό να διερευνηθεί η επίδραση της αρχιτεκτονικής στις ιδιότητες αυτές. Επιπλέον εξετάσθηκε και ο μικροφασικός διαχωρισμός τόσο των γραμμικών όσο και των αστεροειδών τριπολυμερών και ο ρόλος που παίζουν η αρχιτεκτονική και τα μοριακά χαρακτηριστικά των πολυμερών. Η πραγματοποίηση πειραμάτων δυναμικής μηχανικής ανάλυσης καθώς και διαφορικής θερμιδομετρίας σάρωσης σε αστεροειδή πολυμερή πολύστυρενίου, πολύ(μεθακρυλικού εξυλεστέρα) και πολύ(μεθακρυλικού μεθυλεστέρα) και στα αντίστοιχα γραμμικά τους πολυμερή οδήγησαν σε ενδιαφέρον συμπεράσματα. Έγινε σαφές πως η δομή και το μοριακό βάρος επηρεάζουν τις ιδιότητες των πολυμερών. / The subject of this research was the synthesis of star-shaped terpolymers An(B-C)n, using the anionic living polymerization. A 4-step methodology in patch reaction was developed which gives polymers of specific molecular structure. This method is expansion of the in-out method which is used to synthesize heteroarm-star copolymers AnBn. The new star terpolymers consist of a core from cross-linked monomers from which derive two kind of branches theoretically equal in number. One is branches of homopolymer A and the other is branches of diblock copolymer (B-C). For this aim a variety of monomers and cross-linking agents was used. Different cores were made on the nature (DVB,EGDMA) and the size (DVB/St) in order to investigate their effect. Through the synthetic methodology we were able to molecular characterize each step which was vital for the final polymer. The polymers were well characterized through specific techniques. In order to measure the molar mass (Mw and Mn) and the polydispersity, I (Mw/Mn), we used Size Exclusion Chromatography (SEC) technique. The number of the branches was calculated by the Static Light Scattering (SLS) technique. Nuclear Magnetic Resonance spectroscopy (1 H-NMR) was used to calculate the percentage of each homopolymer to the terpolymer. Moreover in order to compare the properties of star and linear terpolymers, ABC linear terpolymers were synthesized by sequential addition. The final polymers were purified through the soxhlet technique with cycloexane. The properties of heteroarm star-like terpolymers were studied comparing with that of the corresponding linear terpolymers (the block and arm lengths were equal) in order to understand the effect of the macromolecular architecture on these properties. Moreover the microphase separation was examined in order to study the effect of the architecture and the molecular characteristics on the terpolymers. The Dynamic Mechanical Analysis (DMA) and Differential Scanning Calorimetry (DSC) experiments on linear and star terpolymers with polystyrene (PS), poly(hexylmethacrylate) (PHMA) and poly(methylmethacrylate) (PMMA) result in interesting conclusions. These conclusions gave us a clear proof that the molecular characteristics and the architecture of the polymers infect their properties.

Shaped charges are a well established type of projectile, subjected to a lot of research ever since emerging as a viable technology in the 1940s. The penetration achieved by shaped charges decreases with increased standoff distance. This is often attributed to the shaped charge jet losing its coherence. The Swedish Defence Research Agency however, noted no such loss of coherence in its experiments. An alternative explanation to the decrease of penetration was instead proposed. The object of this thesis was to investigate this proposed theory. To this end, the hydrocode Autodyn was used, modelling the impact of a high-velocity projectile into a generic target and analysing the resulting behaviour of the target. Several setups were used and several parameters were considered when evaluating the results. The conclusion of this thesis is that the alternative explanation offered is not supported by the observed behaviour of the target in the computer model.

With the emergence of flexible display technologies, graphical user interfaces will no longer be limited to flat surfaces. As such, it will become necessary for interface designers to move beyond flat display designs, contextualizing interaction in an object’s physical shape. Grounded in early explorations of Organic User Interfaces (OUIs), this thesis examines the evolving relationship between industrial and interaction design and argues that not only what, but how we design is changing. To understand how to better design OUIs, we report on an empirical study of pointing behavior that shows how Fitts’ law can model movement time on an extremely convex surface. We also show that touch sensing technology can be repurposed for the OUI design process by making it possible to tape, draw, or paint touch sensing directly on a physical prototype. We then discuss how supporting sketching, a fundamental activity of many design fields, is increasingly critical for the interactive three-dimensional forms in OUI and that a ‘hypercontextualized’ approach to their design can reduce the drawbacks met when everyday objects become interactive. Finally, we discuss that when interactive hardware is seamlessly melded into an object’s shape, the ‘computer’ disappears. When designing OUIs, it is better seen as a basic material, like the clay, foam core, or plastics used by an industrial designer, and one that happens to have interactive potential. / Thesis (Ph.D, Computing) -- Queen's University, 2014-01-23 12:00:08.953

No description available.

Magister Scientiae - MSc (Biotechnology) / The vaginal mucosa is dominated by Gram positive, rod shaped lactobacilli which serve as a natural barrier against infection. In both healthy and BV infected women Lactobacillus crispatus and Lactobacillus jensennii has been found to be the predominant Lactobacillus species. Many studies have been conducted to assess factors influencing lactobacilli dominance in the vaginal microbiome. However, no study has evaluated the impact of plasmids on the vaginal lactobacilli. In the present study two plasmids, pLc17 and pLc4, isolated from vaginal Lactobacillus species of both healthy and BV infected women were characterized. pLc4 was present in both Lactobacillus crispatus and Lactobacillus jensennii while pLc17 was only present in Lactobacillus crispatus. pLc17 (16663 bp in size) encoded a ribonucleotide diphosphate reductase (RNR), a filamentation induced by cAMP-like (FIC-like) protein and numerous mobile elements.

In addition to its various military applications, shaped charges have been used in oil industry as an oil well perforator (OWP) to connect oil and gas to their reservoirs. The collapse of the liner material under the explosive load produces a hypervelocity jet capable of achieving a deep penetration tunnel into the rock formation. The achieved penetration depends on the OWP design, which includes the geometry and the material of the explosive and the liner as well as the initiation mode and the casing of the shaped charge. The main purpose of this research is to assess the performance of OWP with different design aspects in terms of its penetration depth into concrete material.This research employed the Autodyn finite difference code to model the behaviour of OWPs in the stages of liner collapse, jet formation and jet penetration. The design parameters of OWPs were studied quantitatively to identify the effect of each individual parameter on the jet characteristics and the jet penetration depth into concrete material according to the API-RP43 standard test configuration. In order to validate the Autodyn jetting analysis, this research compared the jetting simulation results of copper OWP liners with those obtained from flash x-ray measurements while the numerical jet penetration into the laminated concrete target was validated experimentally by the static firing of OWPs. Above-mentioned experiments were designed and performed in this project.The validated hydrocode was implemented in this research to study the effects of the concrete target strength, the liner material and the liner shape on the jet penetration depth into concrete targets.For the target strength, the traditional virtual origin (VO) penetration model was modified to include a strength reduction term based on Johnson’s damage number and the effect of the underground confinement pressure using Drucker-Prager model. The VO analytical model is also implemented in the liner material study to account for the jet density reduction phenomena and its induced reduction of jet penetration capability. The jets obtained from machined copper and zirconium liners and from copper-tungsten powder liner all exhibited the density reduction phenomena. The modified VO model considers the non-uniform distribution of jet density based on the jet profile analysis using Autodyn and the experimental soft recovery for some tested liners. The results lead to a modified VO penetration model including the non-uniform jet density effect.For zirconium liner material, numerical and analytical studies were conducted for different flow velocities and different collapse angles in order to determine the boundaries between the jetting and non-jetting phases and whether a coherent or a non-coherent jet will form. This study indicated that the suggested four different liner shapes (i.e. the conical, the biconical, the hemispherical and the bell) will produce coherent jet when the zirconium is used as OWP liner.The validated Autodyn hydrocode is also used in this thesis to calculate the velocity difference between two neighbouring zirconium jet fragments. The velocity difference is related directly to the breakup time of an OWP jet, and thus, it is calculated for a range of zirconium liners with different liner wall thicknesses. The calculated values of velocity difference gave a clear insight for the breakup time formulae for zirconium jet in terms of the liner thickness and the charge diameter.

Animal trainers use shaping to teach many behaviors. However, during shaping, the organism may engage in behaviors other than the target behavior or approximations to the target behavior. If the animal is engaged in other behaviors, the rate of reinforcement may decrease and the trainer may resort to what is sometimes referred to as a “desperation click.” That is, the trainer delivers one reinforcer for a behavior that is not a successive approximation to the target response. Anecdotal reports from trainers suggest that sometimes the animal continues to repeat this other behavior that received only one reinforcer, even in the absence of further reinforcement for that behavior. This study compared whether, during a one minute extinction period, participants spent more time engaged in a behavior that had been reinforced only once after a brief period of no reinforcement or in a behavior that had been reinforced multiple times. Participants, who were university students, played a tabletop game that involved touching and manipulating small objects. Five conditions were repeated twice for each participant: reinforcement for interacting with a training object alone, reinforcement for interacting with a training object with other objects present, reinforcement for interacting with a target object, one reinforcer for interacting with a third object immediately following a brief period of no reinforcement, and reinforcement for interacting with any object. Results from this study show that a desperation click situation can be reliably produced in a controlled setting. When participants received one reinforcer for interacting with a new object following a period of no reinforcement, they interacted with the new object for a longer or equal amount of time as compared to an object that had a history of reinforcement.

Esta Tesis doctoral está enfocada en la síntesis de nanopartículas de platino (Pt) con forma controlada para la oxidación de amoniaco, un compuesto que puede ser utilizado como combustible para pila de combustibles y que asegura varios beneficios incluyendo cero emisiones de CO2, la posibilidad de la obtención de tecnología inspirada en el reciclaje de aguas residuales y sensores de amoniaco. Teniendo en cuenta estos beneficios, diversas investigaciones se han enfocado el estudio de los catalíticos más activos para la oxidación de amoniaco y han encontrado que las nanopartículas de Pt preferencialmente cúbicas son la que mayor actividad catalítica presentan. Sin embargo, desde un punto de vista aplicado, todavía faltan metodologías fáciles, baratas y escalables. Durante los últimos años, se ha trabajado, en esta Tesis Doctoral, la síntesis, caracterización y determinación de la actividad catalítica de las nanopartículas de Pt con formas preferenciales. La innovación en este trabajo ha sido en el método de síntesis que consiste en una microemulsión de agua en aceite, con la peculiaridad de agregar ácidos como agentes modificadores de la estructura. En este trabajo se ha propuesto hallar una alternativa que cumpla con la posibilidad de que puedan sintetizarse nanopartículas a gran escala para poder introducirlas en aplicaciones comerciales. En el primer trabajo publicado, se utilizaron distintas concentraciones de HCI en la fase acuosa de la microemulsión para estudiar el efecto modificado, de dicho compuesto. En este artículo, se reportó por primera vez, la síntesis de nanopartículas de platino preferencialmente cúbicas, utilizando el método de microemulsión de agua en aceite que, a diferencia de los métodos más conocidos, esta puede ser escalable. Este control de la forma / estructura de la superficie está determinado por la concentración de HCI en la fase acuosa de la microemulsión. Los resultados demostraron que el porcentaje óptimo de HCI fue aproximadamente 25% con la cual se logró obtener la mayor concentración de nanoestructuras de Pt preferencialmente cúbicas. Los resultados mostraron que las nanopartículas de Pt cúbicas preferenciales sintetizadas eran el mejor catalizador para la oxidación del amoniaco. El segundo artículo publicado abarca la síntesis de (100) nanopartículas de Pt de orientación preferencial, con un tamaño de partícula de aproximadamente 9 nanómetros, mediante el uso del mismo método de síntesis, pero en este caso, la estructura de las nanopartículas fue inducida con la presencia de H2SO4 en la fase acuosa de la microemulsión. Los resultados informados en este artículo mostraron como grandes cantidades de H2SO4 (hasta un 25%) conducen a la formación de nanopartículas de Pt que contienen una mayor cantidad de (100) sitios en su superficie y consecuentemente una forma preferencialmente cúbica. En la tercera publicación, también se utilizó la microemulsión de agua en aceite, pero en presencia de varios modificadores y precursores metálicos para obtener nanopartículas de Pt con orientación preferencial. Las nanopartículas cúbicas enriquecidas en sitios (100), se prepararon utilizando concentraciones específicas de HCI, HBr, H2S04 y H3PQ4. En cuanto a la utilización de ácido cítrico y oxálico como agentes modificadores, un aumento en la cantidad de (111) sitios, fue reportada. Esta faceta es más característico en nanopartículas con estructura octahedral. Las nanopartículas se caracterizaron electroquímicamente con adsorción/desorción de hidrógeno y germanio, así como por adsorción de CO. Finalmente, se evaluó la actividad electrocatalítica de las nanopartículas con el mayor porcentaje de sitios (100) para determinar la oxidación de amoniaco, lo que confirmó los resultados de la caracterización electroquímica. Las nanopartículas de Pt modificadas con HCI al 15% y sintetizadas utilizando K2PtCl4 como el precursor de Pt, mostraron Ia mayor cantidad de sitios (100) (46.7%) y obtuvieron una actividad catalítica más alta sobre la oxidación de amoníaco. De los trabajos no publicados, se han obtenido resultados interesantes incluyendo la síntesis de nanopartículas bimetálicas Pt/Rh de forma controlada utilizando el método similar al utilizado para la síntesis de las nanopartículas de Pt preferencialmente cúbicas. Las nanopartículas que se sintetizaron Pt75/Rh25 y Pt90/Rh10 con 20% de HCI en la fase acuosa, mostraron una actividad superior para la oxidación del etanol con mayor densidad de corriente y un desplazamiento del potencial de inicio a potenciales más bajos. En cuanto a la actividad catalítica presentada para la oxidación de amoníaco, las nanopartículas todas las nanopartículas Pt/Rh sintetizadas, presentaron una disminución en la actividad catalítica, sin embargo, hubo mejoras en el desplazamiento del potencial de inicio con valores menos positivos, para las muestras Pt75/Rh25 y Pt90/Rh10. La caracterización de superficie determinada por el análisis del microscopio de transmisión de electrones (TEM) y dispersión de electrones por rayo X (EDX), confirmó la modificación estructural por la presencia de los ácidos. Las imágenes TEM de las nanopartículas tenían una estructura preferencialmente cúbica. El análisis por EDX confirmó que la composición de cada uno de los metales en las de las nanoestructuras bimetálicas fue cercano a los valores con los que se prepararon las nanopartículas experimentalmente. De este trabajo se propone la realización de una nueva publicación. Finalmente, un estudio preliminar con monocristales de Pt fue realizado para explicar el efecto de los cloruros en inducir la formación de estructuras de Pt preferencialmente cúbicas en la síntesis de microemulsión agua en aceite. Para la realización de estos experimentos se tomaron los monocristales de Pt con planos de base [Pt (100), Pt (111) y Pt (110)] y Pt poliorientado [Pt(poly)]. En este estudio se pudo realizar un análisis del comportamiento electroquímico de los monocristales de Pt en concentraciones elevadas tanto de HCI como de H2S04. Sin embargo, pese a los distintos experimentos realizados, este estudio requiere de más investigación para poder llegar a conclusiones que den lugar al objetivo del estudio. Por último, en esta Tesis Doctoral se destacan varias colaboraciones, científicas realizadas con el propósito de determinar el rendimiento catalítico del material preparado. La primera colaboración ha sido con el grupo de investigación Micro-G que también es dirigido por mi director en la Universidad de Puerto Rico, el Dr. Carlos cabrera. En este proyecto, colaboramos con la preparación del catalizador para aumentar el rendimiento en las densidades de corriente de la oxidación de amoníaco en condiciones de microgravedad. Las medidas cronoamperométricas se realizaron durante 30 parábolas en el avión C9 de la NASA conocido como 'The Weightless Wonder', en enero de 2016 desde Ellington Field en Houston, Texas. Una publicación en la revista 'Microgravity Science and Technology' en 2017 fue producto de dicha colaboración. Otra colaboración realizada fue la preparación de electrodos para la determinación del rendimiento en un sistema microbiano de células en media­celda. Esta colaboración fue parte de un proyecto de investigación doctoral de la Dra. Myreisa Morales de la Universidad de Puerto Rico en Río Piedras. Este proyecto consistió en la deposición de nanopartículas de Pt preferencialmente cúbicas junto con el crecimiento de la bacteria P Vulgaris, en un electrodo de preparado con hebras de fibras de carbono, para la oxidación de amoníaco en un sistema bio-electroquímico. Esta colaboración también está en proceso de poder publicarse. Finalmente, se realizó otra colaboración con el grupo de investigación Micro-G mediante la preparación del procedimiento experimental de oxidación de amoníaco en nanocubos de Pt que sería enviado a la Estación Espacial Internacional (ISS). Se espera que el sistema sea lanzado fuera al espacio exterior en noviembre de 2019. Los resultados podrán ser comparados con los obtenidos para determinar los efectos de la gravedad cero. Se espera que la colaboración realizada logré otra publicación científica.

Previous studies indicate that increasing the diffusion angle in conical film-cooling holes leads to an improvement in their film cooling effectiveness. Discharge coefficient and film cooling effectiveness measurements are conducted to characterize this behavior. Part of the focus of this investigation is to find out how this trend develops and attempt to ascertain the optimum cone angle, if possible. Six test plates, each with one row of eight conical-shaped cooling holes of equal diffusion angles of 0, 1, 2, 3, 6, or 8 [degrees], with respect to the hole axis are used in this study. The ratios of the hole exit areas to the inlet areas range from 1 to 2.85. Coolant injection angle for all holes is at 35 degrees to the horizontal, in the direction of the main flow. Coefficients of discharge of all holes are reported under flow conditions. Temperature sensitive paint, TSP, is the technique used to find the temperature distribution downstream of the cooling holes and determine the laterally averaged film-cooling effectiveness. Data are obtained for blowing ratios ranging from 0.5 to 1.5, at a constant density ratio of 1.26. Results and trends are compared with established literature, which also recommends that a cylindrical entry length for diffused holes should be at least 4 diameters long. The effect that an added entry length has on the 3-degree conical plate's cooling effectiveness is also explored. Data are compared to baseline cylindrical holes, as well as to fan-shaped film holes found in open literature. Results indicate that the conical holes with larger diffusion angles provide strikingly even film protection and outperform fan shaped and cylindrical holes under certain conditions over extended downstream distances. Also, the addition of a cylindrical entry length to a conical hole, by providing a manageable metering diameter, should ease their usage while providing the full benefits of the conical geometry which may one day lead to numerous industrial applications.