Rotordynamic instability problems in turbomachinery have become more important in recent years due to rotordynamic components with higher speeds and higher power densities. These features typically lead to increased instability risk in rotor dynamic components as fluids-structure interactions take place. In addition, critical damage of rotordynamic components can result from high level vibrations of supporting bearing system, where the reduced rotor speed can lead to system operating near the rotor critical speed. Therefore, increased accuracy in modeling of rotordynamic components is required to predict the potential instability issues in high performance rotordynamic design. The instability issue may potentially be eliminated in design stage by varying the characteristics of the unstable components. One such turbomachinery component is the annular pressure seal. The annular pressure seals are specifically designed to prevent the fluid leakage from high pressure stage to low pressure stage in turbomachinery. Typical annular pressure seals have two different flow regions, an annular jet-flow region between the rotor and stator, and cylindrical or circumferential indentions on the stator/rotor surface that serve as cavities where flow recirculation occurs. As the working fluid enters the cavities and recirculates, the kinetic energy is reduced, resulting in a reduction of leakage flow. The current challenge is to model with higher precision the interaction between the rotordynamic components and the working fluid. In this dissertation, this challenge was overcome by developing a hybrid Bulk Flow/CFD method to compute rotordynamic responses for the annular pressure seals. In addition, design of experiments studies were performed to relate the surface patterning with the resulting rotordynamic response for the annular pressure seals, in which several different geometry specifications were investigated. This study on annular pressure seal design generated regression models for rotordynamic coefficients that can be used as optimization guidelines. Research topics related to the annular pressure seals were presented in this dissertation as well. The reduced order model of both hole-pattern seals and labyrinth seals were investigated. The results showed that the flow field representing the flow dynamics in annular pressure seals can be expressed as a combination of first three proper orthogonal decomposition modes. In addition, supercritical state of carbon dioxide (sCO2) process fluid was examined as the working fluid in a preliminary study to better understand the effects on annular pressure seals. The results showed that the performance and stability in the annular pressure seals using sCO2 as process fluid can both be improved. / Doctor of Philosophy / This dissertation focused on understanding the correlations between surface patterning and rotordynamic responses in the annular pressure seals. The annular pressure seals are a specific type of rotordynamic component that was designed to prevent the fluid leakage from high pressure stage to low pressure stage in turbomachinery. As the working fluid enters the cavities and recirculates, the kinetic energy is reduced, resulting in a reduction of leakage flow through the annular pressure seals. Rotordynamic instability becomes an issue that may be related to the annular pressure seals in some cases. In recent years, rotordynamic components with higher rotor speeds and higher power densities are commonly used in industrial applications. These features could lead to increased instability risk in rotor-bearing systems as fluids-structure interactions take place. Therefore, high precision modeling of the rotodynamic components is required to predict the instability issues in high performance rotordynamic design. The instability issue may potentially be eliminated in design stage by varying the characteristics of the potentially unstable components. In this study, the surface patterning and rotordynamic responses were investigated for several different annular pressure seal models with a hybrid Bulk Flow/Computational Fluid Dynamics method. This dissertation provides for the first time regression models for rotordynamic coefficients that can be used as optimization guidelines. Research topics related to the annular pressure seals were presented in this dissertation as well. The reduced order model of both hole-pattern seals and labyrinth seals were investigated. The results showed that the flow field representing the flow dynamics in annular pressure seals can be expressed as a combination of first three proper orthogonal decomposition modes. In addition, supercritical state of carbon dioxide (sCO2) process fluid was examined to better understand the effects of working fluid on annular pressure seals. The results showed that the performance and stability in the annular pressure seals using sCO2 as process fluid can both be improved.

This study examines how themes, conventions and concepts in Gothic discourses are remediated or developed in selected works of contemporary interactive fiction. These works, which are wholly text-based and proceed via command line input from a player, include Nevermore, by Nate Cull (2000), Anchorhead, by Michael S. Gentry (1998), Madam Spider’s Web, by Sara Dee (2006) and Slouching Towards Bedlam, by Star C. Foster and Daniel Ravipinto (2003). The interactive fictions are examined using a media-specific, in-depth analytical approach. Gothic fiction explores the threats which profoundly challenge narrative subjects, and so may be described as concerned with epistemological, ideological and ontological boundaries. In the interactive fictions these boundaries are explored dually through the player’s traversal (that is, progress through a work) and the narrative(s) produced as a result of that traversal. The first three works in this study explore the vulnerabilities related to conceptions of human subjectivity. As an adaptation of Edgar Allan Poe’s famous poem “The Raven,” Nevermore, examined in chapter one, is a work in which self-reflexivity extends to the remediated use of the Gothic conventions of ‘the unspeakable’ and ‘live burial’ which function in Poe’s poem. In chapter two, postmodern indeterminacy, especially with regard to the tensions between spaces and subjective boundaries, is apparent in the means through which the trope of the labyrinth is redesigned in Anchorhead, a work loosely based on H. P. Lovecraft’s terror fiction. In the fragmented narratives produced via traversal of Madam Spider’s Web, considered in chapter three, the player character’s self-fragmentation, indicated by the poetics of the uncanny as well as of the Gothic-grotesque, illustrates a destabilized conception of the human subject which reveals a hidden monster within, both for the player character and the player. Finally, traversal of Slouching Towards Bedlam, analyzed in chapter four, produces a series of narratives which function in a postmodern, recursive fashion to implicate the player in the viral infection which threatens the decidedly posthuman player character. This viral entity is metaphorically linked to Bram Stoker’s vampire, Dracula. As it is the only work in the study to present a conception of posthuman subjectivity, Slouching Towards Bedlam more specifically aligns with the subgenre ‘cybergothic,’ and provides an illuminating contrast to the other three interactive fictions. In the order in which I examine them, these works exemplify a postmodern development of the Gothic which increasingly marries fictional indeterminacy to explicit formal effects, both during interaction and in the narratives produced.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The use of computational fluid dynamics (CFD) as a design tool is becoming increasingly popular in the water resources field. This thesis aims to extend the knowledge of CFD and determine the usefulness of current CFD programs as a modelling tool. This thesis also seeks to determine the accuracy of CFD modelling when compared to physical modelling, the more established form of model testing. It is important that research is conducted on the validation of CFD because with an increase in computer power, processing speed and continual development in the programs used to generate the models, CFD could become an essential tool for the hydraulic engineer. A current key difficulty faced by CFD programs is the mapping of the free surface level of a body of fluid in a two-phase (water and air) flow condition. This is further complicated by the existence of three-dimensional flow over a labyrinth weir and a fluctuating nappe, which at times requires a free surface level to be mapped both above and below the nappe. This thesis begins by detailing the design methods and actual design of a typical labyrinth weir. It then describes the construction of a 1:20 scale physical model, testing procedures, goals, and the results of the physical model tests. Following the physical model study, the thesis discusses the development of a three-dimensional CFD model, designed in a way that matched the physical model. Simulation results obtained from the CFD model are then compared to those from the physical model study and the accuracy and suitability of CFD modelling as a design tool are evaluated. This evaluation considers the surcharge upstream of the weir and transient pressures on the weir. The thesis concludes with recommendations for further research in this field. The results achieved show that the CFD model was able to accurately map the movement of particles within the domain, to fully develop a flow profile, and to accurately predict the water surface level. The pressure readings obtained during CFD modelling were in the same order as those obtained during physical modelling. However, the CFD modelling pressure readings did not often accurately correspond with the physical modelling data, with the average error being 92%. These results indicate that there is still further development required in CFD before it can be relied upon as a design tool independent of other experimental methods. The difficulty and the length of time taken to generate the results also indicate that, at this stage and in this particular scenario, the engineer would be better served through the use of a physical model. / AFRIKAANSE OPSOMMING: Die gebruik van gerekenariseerde vloeidinamika (CFD) as ’n ontwerpinstrument het toenemend gewild begin raak op die gebied van waterhulpbronne. Die doel van hierdie verslag is om kennis van CFD uit te brei en die nut van huidige CFD-programme as ’n modelleringsinstrument te bepaal. Daar word voorts ook gepoog om die akkuraatheid van CFD-modellering te bepaal in vergelyking met fisiese modellering – die meer gevestigde vorm van modeltoetsing. Dit is noodsaaklik dat navorsing gedoen word oor die bekragtiging van CFD, want met ’n toename in rekenaarkrag, verwerkingsnelheid en deurlopende ontwikkeling in die programme wat gebruik word om die modelle te genereer, sal CFD ’n noodsaaklike instrument vir die hidroulika-ingenieur word. ’n Belangrike probleem wat CFD-programme tans inhou, is die kartering van die vry oppervlak van ’n liggaam vloeistof in ’n tweefasse vloeitoestand (water en lug). Dit word verder bemoeilik deur die bestaan van driedimensionele vloei oor ’n labirint-stuwal en ’n skommelende “nappe”, wat by tye vereis dat ’n vry oppervlak sowel bo as onder die “nappe” gekarteer met word. Die verslag begin met ’n uiteensetting van die ontwerpmetodes en fisiese ontwerp van ’n tipiese labirintstuwal. Die bou van ’n 1:20-skaal- fisiese model, toetsprosedures, doelwitte en die resultate van die toetse op die fisiese model word dan beskryf. Ná die studie van die fisiese model, word die ontwikkeling van ’n driedimensionele CFD-model bespreek, wat ontwerp is om by die fisiese model te pas. Die simulasie-resultate van die CFD-model word dan vergelyk met dié van die studie van die fisiese model en die akkuraatheid en geskiktheid van CFD-modellering as ’n ontwerpinstrument word geëvalueer. In hierdie evaluering word die opdamming stroomop van die stuwal en druk op die stuwal ondersoek. Die verslag word afgesluit met aanbevelings vir verdere navorsing op hierdie gebied. Die resultate toon dat die CFD-model die beweging van partikels in die domein akkuraat kon karteer ten einde ’n volledige vloeiprofiel te ontwikkel en die watervlak akkuraat te voorspel. Die drukke wat tydens CFD-modellering verkry is, stem egter nie ooreen met die lesings wat tydens fisiese modellering verkry is nie. Die gemiddelde fout is 92%. Hierdie resultate toon dat verdere ontwikkeling in CFD nodig is voordat daarop staat gemaak kan word as ’n ontwerpinstrument wat onafhanklik van ander eksperimentele metodes gebruik kan word. Die moeilikheidsgraad en die lang tydsduur betrokke by die generering van resultate is ook ’n aanduiding dat die gebruik van ’n fisiese model die ingenieur op hierdie stadium en in hierdie spesifieke scenario beter tot diens sal wees.

Esta tese investiga proximidades entre as proposições de Hélio Oiticica e conceitos como \'construção de situação\', \'deriva\' e \'urbanismo unitário\' desenvolvidos pela Internacional Situacionista - IS (1957-1972). Além da literatura da área, foram explorados dois corpus documental, os Boletins da Internacional Situacionista e o Catalogue Raisonné de Hélio Oiticica. A partir dos Boletins foi possível compreender a formulação dos principais conceitos situacionistas, enquanto o Catalogue Raisonné de Hélio Oiticica possibilitou reconstituir suas deambulações urbanas. Suas caminhadas pela cidade refletem sua crítica à cidade e aos modos de vida urbano. Este caráter crítico está presente no desenvolvimento de seu Programa Ambiental, onde suas proposições estéticas buscam reestabelecer, justamente, as relações entre o indivíduo e a cidade. Os arquivos consultados, manuscritos, cartas, entrevistas, e um grande número de documentos inéditos foram fundamentais para a reconstrução de seus \'passos\' e o entendimento, a partir de seu próprio discurso, de suas relações com a crítica social e urbana desenvolvida pelos situacionistas. / This thesis investigates proximities between propositions of Hélio Oiticica and concepts such as \'situation\', \'dérive\' and \'unitary urbanism\' developed by the Situationist International - IS (1957-1972). Besides the literature of the field, two documentary corpus were explored, the Bulletins of the Situationist International and Catalogue Raisonné of Hélio Oiticica. From the Bulletins it was possible to understand fundamental Situationist concepts, while the Catalogue Raisonné of Hélio Oiticica allowed to reconstitute its urban wanderings. His strolls reflect his criticism to the city and urban lifestyles. This criticality is present in the developing of his Environmental Program, where his aesthetic propositions seek to reestablish precisely the relationship between the individual and the city. The archives consulted, manuscripts, letters, interviews, and a large number of unpublished documents were key elements to rebuilding his \'steps\' and the understanding, based on his own speech, of the relationship between Oiticica and social and urban critics developed by the Situationists.

O anestésico dissociativo Ketamina pertence à classe farmacológica dos antagonistas não competitivos de receptores de glutamato do tipo NMDA. Esta substância é utilizada em situações diversas que envolvem alívio da dor, terapêutica dos quadros depressivos e anestesia parenteral segura. Apresenta a característica de intensificar as experiências sensoriais. Por esta razão, seu consumo entre a população jovem vem crescendo, quadro este que se agrava levando em consideração que boa parte dos indivíduos que fazem uso de Ketamina é de poli usuários. Apresenta também a propriedade de atuar em outros receptores no sistema nervoso central, como: no bloqueio dos receptores colinérgicos muscarínicos, na inibição tônica GABAérgica e na liberação de dopamina. Pouco se sabe sobre as áreas neurais ativadas por seu uso, diante de contextos específicos. Sabe-se, no entanto, que uma delas é o córtex pré-frontal. Supõe-se também sua importância nos transtornos de ansiedade, já que antagonistas de receptores NMDA reduzem sua intensidade, particularmente quando injetados em estruturas que notadamente estão relacionadas à expressão do medo e ansiedade incondicionados, como a substância cinzenta periaquedutal do mesencéfalo. Sendo assim, sugere-se que os efeitos da Ketamina se estendam desde sua influência sobre sistemas encefálicos vinculados à modulação de aspectos da personalidade, cognição e memória, até àqueles vinculados ao prazer, humor, medo e ansiedade. Este trabalho tentou preencher algumas dessas lacunas analisando os efeitos do tratamento crônico de Ketamina em diferentes doses. Grupos independentes de ratos Wistar foram submetidos aos procedimentos de condicionamento ao lugar (3 compartimentos) a caixa claro-escura (2 compartimentos), para tentar estabelecer os efeitos reforçadores e aversivos da Ketamina.Para analisar alterações de cunho emocional geradas pelos tratamentos, foi utilizado o modelo labirinto circular elevado, associado à técnica de marcação imunohistoquímica da proteína Fos para identificar áreas neurais ativadas pela Ketamina no modelo de 3 compartimentos durante o teste. Sugerimos que a Ketamina em baixas doses apresenta a propriedade de induzir forte preferência condicionada ao contexto, este efeito parece depender do tipo de procedimento de escolhas não forçadas. Além disso, os efeitos reforçadores positivos da Ketamina apresentam um padrão dose-dependente, já que altas doses das substâncias produzem aversão e não preferência ao lugar de condicionamento. Em geral, uma mistura de efeitos reforçadores e aversivos foi notada neste trabalho. / The dissociative anesthetic Ketamine belongs to the pharmacological class of non-competitive antagonists of glutamate receptors of the NMDA type. This substance is thechosen onefor many situations involving the pain relief, depressive disorders treatment and safe parenteral anesthesia. It has the characteristic to intensify sensory experiences. Therefore, its consumption among young people is increasing; which will be worse considering that most of the individuals, who take ketamine, useother drugs as well.Ketamine also has the property of acting at other receptors in the central nervous system and the blockade of muscarinic cholinergic receptors of tonic GABAergic inhibition and release of dopamine. However, its influence on serotonergic mechanisms, action focus of most antidepressants, is not known. Nor certain neural areas activated by its use on specific contexts are clearly. It is known, however, that one of them is the prefrontal cortex. It is suspected its importance in anxiety disorders, since NMDA receptor antagonists reduce its intensity, particularly when injected into structures that are particularly related to the expression of unconditioned fear and anxiety, as the periaqueductal gray matter in the midbrain. Thus, this suggests that the effects of Ketamine extend from its influence on encephalic systems underlying the modulation aspects of personality and cognition and memory, to those linked to pleasure, humor, fear and anxiety. This project attempts to fill some of these gaps using independent groups of animals laboratory undergo a conditioned preference procedure by the place and a bright/dark test to try to establish the existence or not of reinforcing effects with the use of Ketamine. In order to identify the possible emotional nature of changes generated by the treatment, we will use the experimental model Preference Conditioned by the Place and the Hight Circular Labyrinth test, associated to immunostaining technique Fos protein. Our results suggest that, in low dosages, Ketamine presents the property of inducing a strong dependence conditioned to the context, this effect seems to depend on the type of procedure and not on the choices. Moreover, the positive reinforcing effects of Ketamine have a dose-dependent pattern, since high doses of the substances produce aversion and not preference to the place of conditioning. In general, a mixture of reinforcing and aversive effects was noted.

Esta pesquisa tem como objeto de estudo principal as manifestações do labirinto nos jogos eletrônicos, dando continuidade às nossas pesquisas sobre o labirinto e à nossa produção artística em novas mídias. As investigações realizadas se deram em duas frentes, sendo uma teórica, onde fizemos uma revisão da bibliografia sobre o labirinto, com a finalidade de termos os subsídios necessários para analisar a presença do labirinto nos jogos eletrônicos. Esta análise se deu em termos espaciais e temporais, tomando a forma de dois capítulos da dissertação, tendo o apoio de estudos na área dos jogos eletrônicos e de referências da literatura e do cinema. Já na frente artística, realizamos nove trabalhos, empregando mídias digitais, que se relacionam, de alguma forma, com a temática desta pesquisa. Apresentamos estes trabalhos ao longo da dissertação, dedicando um breve texto a cada um deles, onde apontamos o diálogo entre eles e os jogos eletrônicos, assim como com referências artísticas, literárias, cinematográficas e teóricas. / This research is concerned with the ocurrences of labyrinths in electronic games, continuing our studies related to labyrinths and our artistic work in new media. The work done comprises two parts; the first one theoretical, where we revised selected references about the labyrinth, aiming to collect elements to analyse the ocurrences of labyrinths in electronic games. This analysis was performed in spacial and temporal terms, comprising two chapters of this dissertation, with the support of studies related to electronic games and literary and cinematographical references. In the artistic part, we developed nine works, using digital media, that are related, somehow, with the subject of this reasearch. These works are introduced along the dissertation, with a short text about each one, where we evidence the dialog between them and electronic games, as well as with artistic, literary, cinematographical and theoretical references.

<p>Most people are familiar with the BRIO labyrinth game and the challenge of guiding the ball through the maze. The goal of this project was to use this game to create a platform for evaluation of control algorithms. The platform was used to evaluate a few different controlling algorithms, both traditional automatic control algorithms as well as algorithms based on online incremental learning.</p><p>The game was fitted with servo actuators for tilting the maze. A camera together with computer vision algorithms were used to estimate the state of the game. The evaluated controlling algorithm had the task of calculating a proper control signal, given the estimated state of the game.</p><p>The evaluated learning systems used traditional control algorithms to provide initial training data. After initial training, the systems learned from their own actions and after a while they outperformed the controller used to provide initial training.</p>

Labyrinth seals are often utilized in locations where contact seals cannot be utilized due to the large displacements of the rotating shaft. The performance evaluation of a labyrinth seal is very important to make sure that optimum performance of turbomachinery is attained. Performance parameters such as carryover coefficient, discharge coefficient were evaluated for a see through triangular tooth on stator labyrinth seal. This computational study investigates how flow conditions and seal parameter variations for see through tooth on stator triangular cavity labyrinth seals affect the value of the carryover coefficient and discharge coefficient. A Finite volume CFD commercial code was used to accomplish the above study. The influence of Reynolds number, rotational speed, seal radial clearance, pitch, tooth angle, tooth width are considered using the finite volume method of computational fluid dynamics. It was found that Reynolds number, high shaft speed and clearance have a significant effect on the carryover coefficient and the discharge coefficient. Clearance is the major influential parameter to be considered among all seal geometric parameters to optimize an ideal seal.

Leibniz’s early conception of individual substance ontology is one of the most puzzling, and fascinating, within the history of philosophy. It is the purpose of this paper to show that: 1) Leibniz did develop a coherent scheme that embodied his substance ontology, 2) the exposition of his early substance ontology is in A Specimen of the Discoveries of the Admirable Secrets of Nature in General, written in 1688 and, 3) the scheme is not sufficiently represented in the Discourse on Metaphysics. Leibniz slowly developed a multifaceted view of substance within the twenty years previous to the writing of the Discourse. This view is comprised of the matter/form complex, the predicate-in-subject thesis and, the phenomenal characteristics of material interaction. These three facets can also be viewed as ontological, teleological/ epistemological, and phenomenological, respectively. These facets were developed concurrently and are interdependent. The understanding of any facet requires the understanding of all of them. From the exploration of Leibniz’s development of substance ontology, one can understand his presentation of rational theology in the Discourse. Leibniz develops the ontology to account for the infinite nature of material division. The unification of material bodies requires explanation. Leibniz has the desire to create a method of deriving a priori knowledge of God, the universe, and humanity; he believes his substance ontology creates the firm basis needed to accomplish this task. The Discourse on Metaphysics does not itself represent the complete scheme Leibniz developed. It shall be shown that A Specimen of the Discoveries of the Admirable Secrets of Nature in General, composed in 1688, is a definitive exposition of Leibniz's early substance ontology. The Discourse on Metaphysics can be viewed as an exposition of rational theology based upon the ontology Leibniz had developed.

Thesis (Ph. D.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xi, 82 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.