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Barreau, Gabriel. "Application d'une méthode semi-implicite couplée avec des outils d'adaptation de maillage anisotropique pour modéliser des arcs continus." Electronic Thesis or Diss., Toulouse, ISAE, 2024. http://www.theses.fr/2024ESAE0059.
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Un avion de ligne est foudroyé en moyenne une à deux fois par an, en considérant la taille des flottes d’avions dans le monde, c’est un phénomène assez fréquent. Lors du foudroiement, le courant injecté peut varier de 200 à 200kA. L’éclair peut alors être divisé en deux phases distincts : la phase impulsionnelle où l’intensité du courant peut atteindre 200kA pendant quelques microsecondes. Elle génère des chocs associés à un écoulement compressible. La phase continue où l’intensité du courant de quelques centaines d’ampères est quasi constant sur une durée de quelques centaines de millisecondes. L’écoulement autour de l’arc a des caractéristiques d’écoulement incompressible.La modélisation de ce phénomène en une seule simulation est très complexe car elle fait intervenir deux physiques d’écoulement différentes, et donc en général la partie continue est modélisée par des méthodes incompressibles et la partie impulsionnelle par des méthodes compressibles. Or, il n’est pas possible de résoudre des écoulements compressibles avec une méthode incompressible, et à cause de la contrainte sur le pas de temps, une méthode compressible n’est pas adaptée pour la résolution d’écoulement incompressible.Comme on souhaite modéliser un foudroiement dans son intégralité, on va chercher des méthodes compressibles capables de résoudre des écoulements bas Mach pour des valeurs de pas de temps raisonnables. Les méthodes semi-implicites sont des méthodes qui en implicitant une partie des termes des équations de conservations permettent de réduire la contrainte sur le pas de temps et permettent alors de résoudre un écoulement bas Mach avec un schéma compressibles.Après une étude bibliographique sur les méthodes existantes, une nouvelle méthode semi-implicite traitant le gaz réel a été développé dans le cadre de cette thèse et a été implémentée dans le code MHD Taranis. La prise en compte des gaz réels est possible grâce à l’utilisation de tables thermodynamiques qui sont générées par le code Sethi. . Pour diminuer les contraintes sur les temps de simulation des géométries 3D, le code Taranis est couplé avec des outils d’adaptation de maillage anisotrope développé à l’INRIA. Ces outils permettent de générer un maillage qui va s’adapter selon l’écoulement de la configuration et donc mailler uniquement aux endroits où c’est nécessaire. Il a été alors nécessaire d’adapter les critères d’adaptation développés pour les calculs de mécanique des fluides à ceux d’un plasma thermique.Pour valider la capacité du nouveau schéma à modéliser des arcs continus, une configuration d’un arc à combustion libre entre cathode en forme de pointe et une anode en forme de plaque est modélisation en 3D. Cette configuration permettra de montrer la capacité du code Taranis à modéliser des arcs continus, et de montrer les intérêts des outils d’adaptation de maillage dans le cas de modélisation d’écoulement plasmaA commercial aircraft is struck by lightning on average once or twice a year. Considering the size of the global aircraft fleet, this is a fairly common phenomenon. During a lightning strike, the injected current can vary from 200 to 200 kA. The lightning can then be divided into two distinct phases: the impulsive phase, where the current intensity can reach 200 kA for a few microseconds, generating shocks associated with compressible flow; and the continuous phase, where the current intensity of a few hundred amperes remains almost constant over a duration of a few hundred milliseconds. The flow around the arc has incompressible flow characteristics during this phase.Modeling this phenomenon in a single simulation is very complex because it involves two different flow physics, so generally, the continuous part is modeled using incompressible methods, and the impulsive part using compressible methods. However, it is not possible to solve compressible flows with an incompressible method, and due to the time step constraint, a compressible method is not suitable for solving incompressible flow.As we aim to model a lightning strike in its entirety, we will seek compressible methods capable of resolving low Mach number flows with reasonable time step values. Semi-implicit methods are techniques that, by implicitly handling some terms of the conservation equations, reduce the time step constraint and thus allow solving low Mach number flows with a compressible scheme.After a bibliographical study on existing methods, a new semi-implicit method handling real gas was developed as part of this thesis and implemented in the MHD code Taranis. The consideration of real gases is made possible through the use of thermodynamic tables generated by the Sethi code. To reduce constraints on simulation times for 3D geometries, the Taranis code is coupled with anisotropic mesh adaptation tools developed at INRIA. These tools generate a mesh that adapts according to the configuration flow, thus meshing only where necessary. It was then necessary to adapt the adaptation criteria developed for fluid mechanics calculations to those of a thermal plasma.To validate the new scheme's ability to model continuous arcs, a configuration of a free-burning arc between a pointed cathode and a plate anode is modeled in 3D. This configuration will demonstrate the Taranis code's capability to model continuous arcs and show the benefits of mesh adaptation tools in plasma flow modeling
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Wexelblat, Alan Daniel. "A feature-based approach to continuous-gesture analysis." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/29074.
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Vigoda, Benjamin William 1973. "Continuous-time analog circuits for statistical signal processing." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/62962.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2003.Vita.
Includes bibliographical references (p. 205-209).
This thesis proposes an alternate paradigm for designing computers using continuous-time analog circuits. Digital computation sacrifices continuous degrees of freedom. A principled approach to recovering them is to view analog circuits as propagating probabilities in a message passing algorithm. Within this framework, analog continuous-time circuits can perform robust, programmable, high-speed, low-power, cost-effective, statistical signal processing. This methodology will have broad application to systems which can benefit from low-power, high-speed signal processing and offers the possibility of adaptable/programmable high-speed circuitry at frequencies where digital circuitry would be cost and power prohibitive. Many problems must be solved before the new design methodology can be shown to be useful in practice: Continuous-time signal processing is not well understood. Analog computational circuits known as "soft-gates" have been previously proposed, but a complementary set of analog memory circuits is still lacking. Analog circuits are usually tunable, rarely reconfigurable, but never programmable. The thesis develops an understanding of the convergence and synchronization of statistical signal processing algorithms in continuous time, and explores the use of linear and nonlinear circuits for analog memory. An exemplary embodiment called the Noise Lock Loop (NLL) using these design primitives is demonstrated to perform direct-sequence spread-spectrum acquisition and tracking functionality and promises order-of-magnitude wins over digital implementations. A building block for the construction of programmable analog gate arrays, the "soft-multiplexer" is also proposed.
by Benjamin Vigoda.
Ph.D.
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Reed, Anita. "Performance and Perception: An Experimental Investigation of the Impact of Continuous Reporting and Continuous Assurance on Individual Investors." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002680.
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Legault, Julie S. M. Massachusetts Institute of Technology. "Amino : a domestic system for synthetic biology and continuous culturing." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98542.
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Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Title as it appears in MIT Commencement Exercises program, June 5, 2015: Amino : a system for out-of-lab synthetic biology and continuous culturing Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 64-65).
With the ability to transfer a trait from one creature to another purposefully, synthetic biology is advancing across unforeseen domains. From algae cells that convert carbon dioxide to fuel, biocementation bacteria to terraform mars, and lab-grown meat, synthetic biology offers new materials for designers, technologists, and artists to explore, and yet, public opinion lags behind these scientific advancements. Anytime science advances faster than our ability to apprehend it, it produces progress but also fear, suspicion and uncertainty. Amino -- an object that allows direct interaction with microorganisms to experiment with biology as material -- sets out not simply to educate but to also be part of the early culture that metabolizes the changes underway. Amino is a design driven mini-lab that allows users to carry out a bacterial transformation and enables the subsequent care and feeding of the cells that are grown. Inspired by Tamagotchis, the genetic transformation of an organism's DNA is performed by the user through guided interactions, resulting in their synthetic organism for which they can care like you would a pet. Amino is developed using low cost ways of carrying out lab-like procedures in the home and is packaged in a suitcase-sized continuous bioreactor for cells.
by Julie Legault.
S.M.
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Thirkell, Paul. "The integration of digitally mediated imaging techniques with 19th century continuous tone printing processes." Thesis, University of the West of England, Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327367.
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Ishizaki, Suguru. "Typographic performance : continuous design solutions as emergent behaviors of active agents." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/29105.
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Al-Tamimi, Rami Salhab. "Continuous time disaggregation in hierarchical production planning." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001819.
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Lee, Sanghoon. "Econometrics of jump-diffusion processes : approximation, estimation and forecasting." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364734.
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Rahgozar, Mandana Seyed. "Estimation of evapotranspiration using continuous soil moisture measurement." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001812.
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Walsh, Maria. "Indentity-in-motion : the narrative duration of the dis/continuous film moment." Thesis, University of Plymouth, 2003. http://hdl.handle.net/10026.1/361.
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The trajectorv of this thesis is set out like a journey upon which encounters are staged between two films. film theor), and philosophers. such as Slavoj Zizek. Gilles Deletize, and Maurice Merleau-Ponty. An encounter with a moment of image suspension. a cut to the blank screen- in Tacita Dean's film, Disappearance atSea (1996). motivates the beginning of this journey's narrative. My reading of this moment counters the way that suspended film moments have been discussed in terms of non-narrative in 1970s film theory and in the contemporary psychoanalýlic filin theory of Slavoj Zizek. Using Gilles Deleuze's notion of narrativization as a process of serialization. I argue that the supposedly non-narrative moment is coextensive with the spectator's dis/continuity in time as opposed to Slavoj Zizek's static suspension or film theory's distanciation. A performative text based on Disappearance at Sea, which I refer to as a 'montage text' and for which precedence is found in Roland Barthes' writing, acts as an interlude that runs in tandem to the main theoretical trajectory. The generativity of absence that emerges from these encounters, both theoretical and poetic. is heightened in the second half of the thesis by the appearance of another 'montage text' based on Chantal Akerrnan's News From Home (1976). In this text. I reconfigure the negativity of historical readings of absence in Neus From Home where it was related to the impossible question of a woman's desire. In my reconfiguration, absence. rather than suspending time. generates a temporalized space and a spatialized time in which the spectator performs the dis/continuity of narrative duration. In the theoretical trajectory of this movement, Gilles Deleuze is hybridized with aspects of Merleau-Ponty's phenomenology, my argument being that the sublime infinity of Deleuzian serialization requires a relation to embodiment in order for it to be useftil in considering the spectator's relation to the two film encounters with absence. I read this hybridization in terms of a feminine mode of the sublime, which suggests the possibility of the real rather than its negation in representation and contributes to current thinking in feminist philosophy, particularly the work of Elizabeth Grosz.
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Wei, Zijun S. M. Massachusetts Institute of Technology. "Development of an implantable sensor for continuous real-time long-term monitoring of soft tissue biomechanics." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119090.
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Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 85-91).
Measuring the mechanical properties of soft tissue can be an important method to detect pathology. Concerning the brain in particular, correlation between abnormal tissue stiffness and morbidity has been reported for Alzheimer's disease, Parkinson's disease and brain tumors, among others. On a more fundamental level, the nature and behavior of the brain from a mechanical standpoint is relatively understudied, in comparison to those from the chemical, electromagnetic and optical perspective. Current techniques fall into two main categories: one establishes direct contact to measure the deformation of tissue under various mechanical loads, the other solves the inverse problem based on the tissue displacement data collected through a number of imaging modalities. Both categories, however, have their limitations in providing ideal mechanical measurement of the brain, ranging from form factor compatibility, spatiotemporal resolution and accuracy. In this light, this work aims at developing an implantable measurement device that can bypass these limitations and provide in situ, in vivo, real-time, long-term monitoring of soft tissue biomechanics. The initial goal is to create a functional sensor front-end that can differentiate materials of different stiffness. As this project is to continue beyond the thesis, this thesis will present the current development progress, issues encountered and corresponding counter-measures, and discuss the prospective work in the future.
by Zijun Wei.
S.M.
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Lynch, Corey. "Continuous Electrowetting Actuation Utilizing Current Rectification Properties of Valve Metal Films." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3519.
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Electrowetting on dielectric (EWOD) is a technique for reducing the apparent contact angle of a fluid droplet, which has many promising applications in the fields of optics, digital displays, and lab-on-a-chip research. In this thesis, a design is presented for a novel single circuit device for achieving continuous droplet motion, by using the current-rectifying properties of valve metals to create diode-like behavior. This contrasts with existing designs, which require an array of individual electrodes to achieve motion in discrete steps. We are able to demonstrate continuous droplet motion across a 28mm-long test strip with an applied voltage of 303 V and a velocity of 5.59 mm/s (at 370 V) using an ionic-fluid electrolyte (BMIM-PF6), and have achieved actuation at as low as 185 V, with a maximum observed velocity (at 300 V) of 13.8 mm/s using a 1M sodium sulfate solution.
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Sallais, Damien. "Contribution à l'étude de nouveaux matériaux élaborés par métallurgie des poudres pour les contacts électriques soumis aux arcs de coupure et de fermeture du courant continu." Rennes 1, 2007. http://www.theses.fr/2007REN1S162.
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Pour satisfaire la demande croissante en puissance électrique des automobiles modernes, l’actuel réseau sous 14 VDC ainsi que les systèmes de commande qui lui sont rattachés doivent évoluer. C’est le cas en particulier des dispositifs de coupure. Deux solutions envisageables pour répondre à ces besoins en puissance électrique ont tout d’abord été confrontées : l’augmentation du courant sous 14 VDC et le passage à une tension de 42 VDC. L’augmentation de la tension se révèle être l’option la plus intéressante mais exige le développement de nouveaux matériaux de contact. De nouveaux pseudo alliages AgMeO ainsi qu’un matériau composite très innovant ont donc été élaborés et testés électriquement. Ils représentent des solutions matériau très intéressantes en terme de réduction de la durée d’arc et du gap d’extinction. Parallèlement à ces études expérimentales, des calculs théoriques ont été menés afin de simuler l’érosion et le transfert de matière entre les contactsIn order to satisfy the increasing electrical power needs in modern cars, the actual 14 VDC battery and its command systems as switching devices, have to evolve. First, two present tendencies were evaluated: the increase of current levels under 14 VDC and the change of voltage from 14 VDC to 42 VDC. A new 42 VDC system seems to be the more interesting solution, it needs however the development of new electrical contact materials. New silver-oxide composites and an innovating contact material were also elaborated and tested. They exhibit strong improvements in term of arc duration and extinction gap minimization. In addition, a theoretical study using a finite element simulation was led to calculate erosion and material transfer between contacts
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Yusoff, Hamdan bin Mohamed. "Continuous Production of Carbon Nanotubes Using Carbon Arc Reactor : Anode Surface Temperature Study and CFD Modelling." Thesis, University of Canterbury. Chemical and Process Engineering, 2008. http://hdl.handle.net/10092/4386.
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The mass production of carbon nanotubes (CNTs) by a cost effective process is still a challenge for further research and application of CNTs. This research focussed on the deposition of CNTs on a continuously-fed carbon substrate via arc discharge at atmospheric pressure. In this work, modifications, control and optimization of the available arc-discharge reactor were conducted. New reactor support and new tape feeding mechanisms were added to the reactor for better temperature assessment, longer operating period and better control of the speed of the tape.
The influence of inter-electrode gap, substrate velocity and arc current on the surface temperature were investigated. Multiwalled carbon nanotubes (MWNTs) were produced at lower currents (< 20 A) and at larger inter-electrode gaps. Further investigation shows that inter-electrode gap influenced both the arc characteristic and the anode surface temperature (Ts). Here, Ts was measured by an optical pyrometer.
The inter-electrode gap was found to indirectly affect the formation of NTs. Anode surface temperature (Ts) varied with gap, reaching a minimum at an intermediate gap. Higher CNTs yield was found at this lowest Ts. This minimum Ts is consistent with the presence of a cloud of nanoparticles ejected by the heated graphite/carbon surfaces. These graphene fragments are thought to later fold and form nanotube “seeds” and then develop into multiwall nanotubes. This cloud of nanoparticles also may affect the electrical conductivity at the front of the anode. Simulation of the arc behaviour, i.e. temperature distributions and flow properties of the plasma, using a computer package Comsol Multiphysics 3.2, was stable only when the electrical conductivity of a dusty plasma near to the electrodes was included.
Our experiments show that carbon nanotubes grew better at a Ts range of ~ 3650 K - 3700 K and at the tape speed of 3 mm/s. The results from our work also strongly suggested that tiny carbon crystallites are the main intermediates for CNT growth in an electric arc. The limiting factor for a solid state growth mechanism, therefore, is high temperature annealing of carbon or graphene fragments. Further work should aim to understand the growth mechanism of CNTs, produce comprehensive analysis on the arc plasma composition and also explore the possibility of producing CNTs at higher rates.
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Upham, Finn. "Quantifying the temporal dynamics of music listening: a critical investigation of analysis techniques for collections of continuous responses to music." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104495.
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Continuous response measurement offers a data-rich trace of a listener's experiences of music in time. Listeners' responses are most often studied in collections---each a set of time series of the same response measure to the same stimulus from multiple listenings. Inter-response variability and the challenges of time series analysis complicate the interpretation of these collections. This thesis describes traditional and novel methods of analyzing collections of continuous responses to music with the goal of identifying what information can be found in these collections before trying to establish possible relationships to the features of the stimulating music. Besides mathematical investigations of these analysis methods, their potential outcomes are assessed by applying each to forty experimental collections of continuous rating responses and four artificial collections of unrelated continuous rating responses. The traditional analyses studied include the average response time series and Pearson correlations between continuous responses as a measure of response reliability. The chapter on novel techniques introduces activity analysis and coordination tests, evaluates measures of the relative significance of time points in these collection, and applies cluster analysis in search of distinct patterns of response to the same stimuli. The results of these analyses suggest that though music does not provoke the same continuous response from all listeners, musical works can induce distinct and repeatable listening experiences which are measurable in collections of continuous responses.L'évaluation des réactions continues permet d'obtenir un tracé riche en données de l'expérience des auditeurs par rapport à la musique au fil du temps. En règle générale, les réactions des auditeurs sont analysées par ensembles, c'est-à-dire par groupes de séries chronologiques portant sur de mêmes relevés de réactions au même stimulus provenant d'écoutes multiples. La variabilité entre les réactions et les défis inhérents à l'analyse des séries chronologiques rendent l'interprétation de ces ensembles encore plus complexe. La présente thèse décrit des méthodes traditionnelles et nouvelles d'analyse d'ensembles de réactions continues à la musique afin d'identifier quelles informations peuvent être recueillies dans ces ensembles avant de tenter d'établir des liens possibles avec les caractéristiques de la musique stimulante. En plus de l'étude mathématique de ces méthodes d'analyse, leurs résultats potentiels ont été évalués en appliquant chacune d'entre elles à quarante de ces ensembles d'évaluation de réactions continues ainsi qu'à quatre ensembles artificiels d'évaluations de réactions continues non apparentés. Les analyses traditionnelles étudiées comprennent les séries chronologiques moyennes et des corrélations de Pearson entre les réactions continues comme évaluation de la fiabilité de la réaction. Le chapitre portant sur les nouvelles techniques commence par une présentation de l'analyse de l'activité et des tests de coordination. Par la suite, il évalue les mesures de pertinence des repères temporels de ces ensembles, puis il rend compte de l'analyse par regroupements visant à identifier des modèles précis de réactions aux mêmes stimuli. Les résultats de ces analyses sous-tendent que bien que la musique ne provoque pas la même réaction chez tous les auditeurs, l'oeuvre musicale peut créer des expériences d'écoute distinctes et reproductibles pouvant être évaluées dans des ensembles de réactions continues.
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Nayak, Sunita. "A vision-based approach for unsupervised modeling of signs embedded in continuous sentences." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001265.
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Medina, Theresa J. "Physiological responses of men during the continuous use of a portable liquid cooling vest." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000444.
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Santos, Eloiza Marinho dos. "FORMAÇÃO CONTINUADA DE PROFESSORES: concepções, discursos e práticas no Programa ARCO." Universidade Federal do Maranhão, 2007. http://tedebc.ufma.br:8080/jspui/handle/tede/134.
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Previous issue date: 2007-10-29This research is about the teachers' continuous development. It emphasizes, as object of study, the Program of Continuous Development for Teachers: Reconstructive Learning of Knowledge - ARCO, designed by a multidisciplinary team of professionals from the Municipal Public School Network in Imperatriz-MA and it was carried out between 2001 and 2004. It evaluates the repercussions of the graduation granted by the program in pedagogical practice for educators, contributing to the re-significance of the continuous development in that county. It analyzes the theoretical-methodological approaches which are its basis, as well as the meaning and repercussions of that graduation experience, starting from the voice and practice of educators. It also investigates the historical-political settlement context of the program. In the dialogic articulation between collected data in the field research and the theoretical study, it seeks in Demo, consultant of the program and main author studied by the faculties, to analyze the main leading axes of the ARCO, such as the research conceptions as educational principles, emancipation and autonomy, these are also based on Paulo Freire, Gramsci and Giroux, who take up the intellectual (conservative and/or radical organic) as mediator, legitimator and producer of ideas and social practices. That latter author works another concept, the one of intellectual transformer. In Helena Freitas we found the defense of the omni lateral conception of the multiple dimensions of the human graduation and of the theory/practice articulation and valorization of the processes of production of knowledge for the investigation and research, in the continuous development. Resulting from a qualitative approach, the aforementioned research chose as subjects: the education manager from the time of settling and implantation of the ARCO, two members of the Base of Assistants Group, four of the Base of Multipliers Group and three participant teachers of the different moments of the graduation (2002, 2003 and 2004). The following procedures were used to collecting data: the study of the Document-base of the ARCO, analysis of the log books written by the teachers, semi-structured interviews and direct observation of the three teachers' educational practice who teach the fundamental school (3rd grade or 4th year, 6th, 7th and 8th grades or 7th, 8th and 9th years). That whole process allowed to assert that the educators of the school network have difficulties in materializing the theoretical-methodological axes worked in the ARCO in their daily practices, due to the short time they tried the methodology, however there is a recognition of the program as formation referencial in a perspective of commitment with the human and political graduation of the students; the textual elaboration and the devolution became frequent in the speeches and practices; they reveal the importance and the need for the continuous development, as permanent space of reflection of the educational practice, orientation, production and socialization of the personal and collectively built knowledge; inclusion feeling into the program; recognition of the self theoretical limitations and the effort to overcome them; change in the conception of evaluation; practice of reflexive records; the conquest of the condition as subject who is known capable to learn, revealed in several initiatives: production and popularization of the elaborated texts, participation in public contests and accomplishment of lectures, interest in studying, research and elaboration resulting in the educators' insertion in graduation, specialization and even master degrees courses. Moreover, we detach the imperious necessity of the definition of Public Politics of Education that include the continued formation as right and necessity of educators of the municipal public net of Empress and that they, in fact, are fulfilled.
Esta pesquisa trata da formação continuada de professoras/es. Enfatiza, como objeto de estudo, o Programa de Formação Continuada de Professores: Aprendizagem Reconstrutiva do Conhecimento ARCO, elaborado por uma equipe multidisciplinar de profissionais da rede pública municipal de Imperatriz-MA que esteve em vigência no período de 2001 a 2004. Avalia as repercussões da formação realizada pelo programa na prática pedagógica de educadoras/es, contribuindo para a re-significação da formação continuada naquele município. Analisa as abordagens teórico-metodológicas que o fundamentam, bem como o significado e repercussões dessa experiência de formação, a partir da voz e da prática de educadoras/es. Investiga, também, o contexto histórico-político de inserção do programa. Na articulação dialógica entre dados coletados na pesquisa de campo e o estudo teórico, busca em Demo, consultor do programa e principal autor estudado pelos formadores, analisar os principais eixos norteadores do ARCO, como as concepções de pesquisa como princípio educativo, emancipação e autonomia, estas fundamentadas também em Paulo Freire, Gramsci e Giroux, que tratam do intelectual (orgânico conservador e/ou radical) como mediador, legitimador e produtor de idéias e práticas sociais. Esse último autor trabalha um outro conceito, o de intelectual transformador. Em Helena Freitas encontramos a defesa da concepção omnilateral das múltiplas dimensões da formação humana e da articulação teoria / prática e valorização dos processos de produção do conhecimento pela investigação e a pesquisa, na formação continuada. Resultante de uma abordagem qualitativa, a referida pesquisa elegeu como sujeitos: a gestora de educação do período de criação e implantação do ARCO, dois membros do Grupo Base de Assessores, quatro do Grupo Base de Multiplicadores e três professoras participantes de momentos distintos da formação (2002, 2003 e 2004). Foram utilizados os seguintes procedimentos para coleta de dados: o estudo do Documento-Base do ARCO, análise dos diários de bordo escritos pelas professoras, entrevistas semi-estruturadas e a observação direta da prática docente das três professoras que atuam no ensino fundamental. Todo esse processo permitiu concluir que, os educadores da rede têm dificuldades em materializar os eixos teórico-metodológicos trabalhados no ARCO em suas práticas cotidianas, pelo pouco tempo em que experimentaram a metodologia, porém há um reconhecimento do programa como referencial de formação numa perspectiva de compromisso com a formação humana e política dos educandos; a elaboração textual e a devolutiva tornaram-se freqüentes nos discursos e práticas; revelam a importância e a necessidade da formação continuada, como espaço permanente de reflexão da prática docente, de orientação, produção e socialização dos conhecimentos construídos pessoal e coletivamente; sentimento de inclusão no programa; reconhecimento dos próprios limites teóricos e o esforço por superá-los; mudança na concepção da avaliação; prática de registros reflexivos; a conquista da condição de sujeito que se sabe capaz de aprender, revelada em diversas iniciativas. Além disso, destacamos a imperiosa necessidade da definição de Políticas Públicas de Educação que incluam a formação continuada como direito e necessidade dos educadores /as da rede pública municipal de Imperatriz e que elas, de fato, sejam cumpridas.
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Tanaka, Yasunori, Yasunobu Yokomizu, Motohiro Ishikawa, Toshiro Matsumura, and Yukio Kito. "Dominant Spectra of Background Radiation in an SF_6 Post-Arc Channel." IEEE, 1997. http://hdl.handle.net/2237/7279.
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Shastry, Rahul. "Continuous Deposition of Carbon Nanotubes in an Arc-reactor and their Application in Field Emission Devices." Thesis, University of Canterbury. Chemical and Process Engineering, 2007. http://hdl.handle.net/10092/3267.
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Carbon nanotubes have become one of the most important building blocks critical to nanotechnology. Carbon nanotubes have attracted the interests of many scientists since their discovery due to their remarkable properties and have been widely used for various applications. However, the bottle neck in nanotube research has been the lack of a cheap, continuous and fast nanotube production method. This study concerns a reactor where nanotubes are continuously deposited on a carbon substrate using arc discharge at atmospheric pressure. This process appears to be the first to employ an arc discharge as the method for continuous mass deposition of nanotubes on a substrate. This nanotube deposition method eliminates the generic multistep process of nanotube deposition on substrates for its use in many applications. The effect of various parameters influencing growth and morphology of nanotubes on the substrate in the arc reactor (inter-electrode gap, atmosphere composition, current density, flushing, substrate type and speed and catalyst) have been systematically explored to optimise nanotube growth. The field emission properties of the nanotube laden substrate are studied for use and applicability as electron emitters. The nanotube samples demonstrated superior emission properties, low turn-on field and excellent current stability when put into applications such as a luminescent tube and an ionisation sensor. Theoretical modelling of the behaviour of a single nanotube during field emission was performed using finite element analysis software (COMSOL 3.2) to understand the effect of nanotube length, diameter, and vacuum gap on an individual nanotube. The results reveal that resistive heating (temperature) limits the maximum current carried by an individual nanotube. Furthermore, a new growth model is introduced to explain the formation of nanotubes from graphene fragments and nanocrystallites, due to polarisation of carbon species near the electrode surface suggesting that carbon vapour is unlikely to be responsible for nanotube growth.
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Van, Nostrand Caleb. "A Discrete-Continuous Modeling Framework for Long-Distance, Leisure Travel Demand Analysis." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3389.
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This study contributes to the literature on national long-distance travel demand modeling by providing an analysis of households' annual destination choices and time allocation patterns for long-distance leisure travel purposes. An annual vacation destination choice and time allocation model is formulated to simultaneously predict the different destinations that a household visits and the time it spends on each of these visited destinations, in a year. The model takes the form of a Multiple Discrete-Continuous Extreme Value (MDCEV) structure (Bhat, 2005; Bhat, 2008). The model assumes that households allocate their annual vacation time to visit one or more destinations in a year to maximize the utility derived from their choices. The model framework accommodates variety-seeking in households' vacation destination choices in that households can potentially visit a variety of destinations rather than spending all of their annual vacation time for visiting a single destination. At the same time, the model accommodates corner solutions to recognize that households may not necessarily visit all available destinations. An annual vacation time budget is also considered to recognize that households may operate under time budget constraints. Further, the paper proposes a variant of the MDCEV model that avoids the prediction of unrealistically small amounts of time allocation to the chosen alternatives. To do so, the continuously non-linear utility functional form in the MDCEV framework is replaced with a combination of a linear and non-linear form.
The empirical data for this analysis comes from the 1995 American Travel Survey Data, with the U.S. divided into 210 alternative destinations. The empirical analysis provides important insights into the determinants of households' leisure destination choice and time allocation patterns.
An appealing feature of the proposed model is its applicability in a national, long-distance leisure travel demand model system. The annual destination choices and time allocations predicted by this model can be used for subsequent analysis of the number of trips made (in a year) to each destination and the travel choices for each trip. The outputs from such a national travel modeling framework can be used to obtain national-level Origin-Destination demand tables for long-distance leisure travel.
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Greeley, Sam. "The Impact of Continuous and Discontinuous Cycle Exercise on Affect: An Examination of the Dual-Mode Model." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4055.
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Low-volume, high-intensity interval training has been garnering attention in the exercise physiology literature recently due to its proposed time-efficiency. Also, recent work comparing continuous exercise to high-intensity interval training demonstrated superior ratings of perceived enjoyment following interval training. However, the dual-mode model suggests that exercise above ventilatory threshold (VT) done continuously will result in an almost homogenous decline in affect, which may reduce adherence.
Numerous studies confirm the dual-mode model's prediction of reduced affect when exercising above VT, but no research to date has applied the model's predictions to interval training. The purpose of this study was to examine the dual-mode model using interval training. Based on the model, interval exercise above VT should produce a homogenous and significant decline in affect during exercise.
Ten participants (mean age = 21.6 ± 2.4 yrs) completed the study. Participants were screened by a physician's assistant on their first visit to ensure they were low-risk and had no symptoms (cardiovascular, pulmonary, metabolic, or orthopedic) that would preclude safe participation in an exercise training program. Participants performed a maximal exercise test during their second visit to the lab. The final four visits were exercise trials 20 minutes in duration: 1) continuous at 20% below VT [Continuous-Moderate], 2) continuous at VT [Continuous-Heavy, 3) 10 x 60-second intervals at VT [Interval-Heavy], 4) 10 x 60-second intervals at 20% above VT [Interval-Severe].
Results indicated that enjoyment and affect was significantly greater during Continuous-Moderate and Interval-Heavy compared with Continuous-Heavy. Interval-Severe approached inducing significantly greater enjoyment and affect compared with Continuous-Heavy, however the study was likely underpowered to achieve significance. The findings of this study suggest that utilizing interval training may help preserve affect, even when performing exercise above VT.
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Dong, Wei. "Chinese Cultural Center." VCU Scholars Compass, 1988. http://scholarscompass.vcu.edu/etd/677.
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During this period of high technology, designers are eager to create environments that have strong emotional appeal to people's physiology and psychology. Our exploration of the natural living space has become all the more an elusive search as modern technology advances. Interior design, in its concern for environmental engineering, endeavors to exploit the spiritual aspect of human resources. Through this message, people are inspired to higher planes of existence.A. PROJECT To design a Chinese Cultural center. B. PURPOSE 1. To introduce the traditional and contemporary Chinese culture to western people. 2. To illustrate and describe the philosophies of Chinese life and thinking to visitors of the center. 3. To create a new space and form combining oriental and western design. 4. To incorporate the use of contemporary materials, structure and technology. 5. To integrate the interior and exterior environment, and the building into a total design concept. 6. To satisfy the functional requirements needed in an exhibition area, guest house facility, restaurant, gift shop, and office area.
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Mehranipornejad, Ebrahim. "Evaluation of AASHTO design specifications for cast-in-place continuous bridge deck using remote sensing technique." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001584.
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Harrison, Arnell. "Evaluating the reliability of continuous resistivity profiling to detect submarine groundwater discharge in a shallow marine environment : Sarasota Bay, Florida." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001714.
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Davies, Huw. "Towards a more versatile dynamic-music for video games : approaches to compositional considerations and techniques for continuous music." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:3f1e4cfa-4a36-44d8-9f4b-4c623ce6b045.
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This study contributes to practical discussions on the composition of dynamic music for video games from the composer’s perspective. Creating greater levels of immersion in players is used as a justification for the proposals of the thesis. It lays down foundational aesthetic elements in order to proceed with a logical methodology. The aim of this paper is to build upon, and further hybridise, two techniques used by composers and by video game designers to increase further the reactive agility and memorability of the music for the player. Each chapter of this paper explores a different technique for joining two (possibly disparate) types of gameplay, or gamestates, with appropriate continuous music. In each, I discuss a particular musical engine capable of implementing continuous music. Chapter One will discuss a branching-music engine, which uses a precomposed musical mosaic (or musical pixels) to create a linear score with the potential to diverge at appropriate moments accompanying onscreen action. I use the case study of the Final Fantasy battle system to show how the implementation of a branching-music engine could assist in maintaining the continuity of gameplay experience that current disjointed scores, which appear in many games, create. To aid this argument I have implemented a branching-music engine, using the graphical object oriented programming environment MaxMSP, in the style of the battle music composed by Nobuo Uematsu, the composer of the early Final Fantasy series. The reader can find this in the accompanying demonstrations patch. In Chapter Two I consider how a generative-music engine can also implement a continuous music and also address some of the limitations of the branching-music engine. Further I describe a technique for an effective generative music for video games that creates musical ‘personalities’ that can mimic a particular style of music for a limited period of time. Crucially, this engine is able to transition between any two personalities to create musical coincidence with the game. GMGEn (Game Music Generation Engine) is a program I have created in MaxMSP to act as an example of this concept. GMGEn is available in the Demonstrations_Application. Chapter Three will discuss potential limitations of the branching music engine described in Chapter One and the generative music engine described in Chapter Two, and highlights how these issues can be solved by way of a third engine, which hybridises both. As this engine has an indeterminate musical state it is termed the intermittent-music engine. I go on to discuss the implementation of this engine in two different game scenarios and how emergent structures of this music will appear. The final outcome is to formulate a new compositional approach delivering dynamic music, which accompanies the onscreen action with greater agility than currently present in the field, increasing the memorability and therefore the immersive effect of the video-game music.
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Jahnke, Robert Hans George. "He tataitanga ahua toi : the house that Riwai built, a continuum of Māori art." Massey University, 2006. http://hdl.handle.net/10179/984.
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Prior to the 1950s, visual culture within tribal environments could be separated into customary and non-customary. In the early 19th century, customary visual culture maintained visual correspondence with prior painted and carved models of the pre-contact period. In the latter part of the 19th century, non-customary painted and carved imagery inspired by European naturalism informed tribal visual culture. This accommodation of European imagery and practice was trans-cultural in its translation to tribal environments. In the 1960s, an innovative trans-customary art form evolved outside tribal environments, fusing customary visual culture and modernism. This trans-customary art form, which maintained visual empathy with customary form of the 19th century, was introduced into the tribal environment, initially, in a painted mural in 1973, and subsequently in a multimedia mural in 1975. In 1989 and 1990, this trans-customary Maori art practice informed the art of the Taharora Project at Mihikoinga marae in Ohineakai. In this Project, the 1970s transcustomary Maori art precedents were extended with non-customary form and practice. The thesis employs tataitanga kaupapa toi as a paradigm for Maori cultural relativity and relevance en-framing form, content and genealogy. Annexed to this paradigm are a range of methods: a tataitanga reo method for interpreting Maori language texts; a tataitanga korero method, conjoining a kaupapa Maori and an iconographic approach, for interpreting meaning in tribal visual culture, and a tataitanga whakairo method, incorporating stylistic analysis as formal sequence, semiology and intrinsic perception, for analysing a continuum of stylistic development from the Rawheoro School of carving to the Taharora Project. The Taharora Project constitutes the case study where tribal visual culture and contemporary art within tribal environments are contextualised in a trans-cultural continuum. The critical question that underpins this thesis is how do form, content and genealogy contribute to art that resonates with Maori? The thesis concludes that trans-cultural practice in contemporary art can resonate with Maori if the art maintains visual correspondence or visual empathy with customary tribal form. In their absence, cultural resonance can be achieved through a grounding of the content, informing the art, in a paradigm of Maori cultural relativity and relevance, a tataitanga kaupapa toi. The genealogy of the artist is a further determinant for resonance.
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Verma, Swati. "Defining service quality in an outpatient clinic with complex constituency." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002240.
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Segerström, Lina. "The movement continues : En kvalitativ textanalys av Donald Trump ur ett propagandaperspektiv." Thesis, Karlstads universitet, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-66688.
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Den 20 januari 2017 tillträdde Donald Trump som USA:s 45e president. Redan under valkampanjen, som Trump gick in i som en politisk outsider, såg vi en ny kommunikationsstil träda i kraft som enligt Enli (2017) bättre kan beskrivas som amatörism. Språket var rakt, direkt och ofiltrerat och tog ett stort kliv ifrån den traditionella politiska kommunikationen. Trumps huvudsakliga kommunikationsplattform är den sociala mediesajten Twitter där han kommunicerar frekvent och monologiskt med sin publik. Genom sin kontroversiella kommunikationsstil som väckt en global debatt kan Trumps kommunikation enligt Davis (2013) liknas vid propaganda från andra världskriget. Denna studie tar genom en kvalitativ innehållsanalys ett grepp om propagandans definition enligt olika teoretiska perspektiv och har därefter för avsikt att analysera Trumps kommunikation på Twitter ur ett propagandaperspektiv. Syftet med studien är att kartlägga om det går att härleda Donald Trumps kommunikation på Twitter till klassisk propaganda från 1937, samt att även belysa genom vilka element detta görs utifrån frågeställningarna: ”Hur kan Donald Trumps twitterinlägg förstås utifrån ett propagandaperspektiv?” Samt ”Vilka likheter/skillnader finns det mellan Trumps twitterinlägg och klassisk propaganda från 1937?”. Till grund för analysen ligger The Institute for Propaganda Analysis, (IPA) sju klassiska propagandaordningar från 1937 vilka utgörs av punkterna: name-calling, glittering generalities, transfer, testimonial, plain folks, och bandwagon (Institute for Propaganda Analysis, 1937) samt Jacques Elluls teori om olika former av propaganda. För att analysera textmaterialet från Twitter användes en hermeneutisk textanalys som grundar sig i läran om läsning och tolkning. Det insamlade datamaterialet är ett urval från Trumps twitterkonto, @real_DonaldTrump, och kom att bestå av 300 tweets under perioden 20 januari – 20 mars 2017 med motivet att denna period representerar Trumps första dagar som USA:s president vilket därmed innebär att en ny politisk kommunikation tog sin början. Genom att analysera samt tolka Donald Trumps twitterinlägg ur IPA:s propagandaordningar framkom tillslut ett resultat som innebar att denna studie avslöjar att två tredjedelar av Donald Trumps tweets kunde tolkas ur IPA:s propagandaordningar. Slutsatsen är således att Donald Trumps kommunikation, trots nya högteknologiska hjälpmedel, kan tolkas ur och liknas vid ett klassiskt propagandaperspektiv som går hela 80 år tillbaka i tiden och kategoriserar därigenom in sig vid Elluls politiska samt horisontella propaganda.January 20th 2017, Donald Trump was inaugurated as the 45th president of the United States of America. Since the start of the campaign, where President Trump entered as a political wild-card, he skillfully displayed a way of communicating never before seen at this level of politics. This style of communicating is according to Enli (2017) better described as unprofessional. The unfiltered, direct and straight-forward language was far from the traditional political environment historically utilized in presidential campaigns. Trumps primary platform for communicating with the surrounding world is the social media site Twitter, where his frequent one-way messages can benefit from the structure of the chosen interface. Davis (2013) connects Trumps controversial way of communicating to the propaganda of World War 2. This study will by qualitative content analysis, research the definition of propaganda from different theoretical perspectives and purpose as an analysis of Trumps communication through Twitter as propaganda. The objective of this study is to define if President Trump’s communicative strategy via Twitter is a derivate from the propaganda of 1937 and also emphasize from what elements this is done by answering the following: “How can Donald Trump’s tweets be interpreted from the perspective of propaganda? What are the similarities/differences that link President Trump’s tweets to classic propaganda from 1937 and if yes, what are these specific similarities?” The analysis is based upon The Institute for Propaganda Analysis (IPA) seven orders of classic propaganda from 1937; name-calling, glittering generalities, transfer, testimonial, plain folks, card stacking and bandwagon (Sproule, 1997 s.129ff) and Jacques Elluls theory of propaganda in different forms. A hermeneutical text analysis, coming from the research of reading and interpreting, was the tool used for the twitter text analysis. The collection of data is extractions from President Donald Trump’s twitter account, @real_DonaldTrump, and consists of 300 tweets submitted between January 20th and March 20th of 2017. This timespan was intentionally chosen in order to target the early days of Donald Trump’s presidency and the dawn of this new way of political communication. The analysis and interpretation of the selected twitter submissions show that 2/3 of them lies within the orders of propaganda defined by IPA. This concludes that President Trumps communication, despite new technological resources, can be interpreted as and compared to classic propaganda spanning 80 years back in time and thereby categorizes as Elluls political and horizontal propaganda.
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Lehto, Heather L. "Self-Potential Anomalies and CO2 Flux on Active Volcanoes: Insights from Time and Spatial Series at Masaya, Telica, and Cerro Negro, Nicaragua." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002108.
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Wasik, Thomas. "Effect of fiber volume fraction on fracture mechanics in continuously reinforced fiber composite materials." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001163.
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Bessini, Muñoz Juan Gabriel. "Form-finding and Performance of Bending-active Structures. Proposals of Application to Lightweight Braced Arches." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/165575.
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[ES] Hoy en día, la arquitectura moderna está orientada principalmente al empleo eficiente de materiales tecnológicos y sostenibles, la tecnificación del proceso de diseño, proyecto y construcción, y la búsqueda de soluciones muy ligeras. Estas ideas se reflejan en las estructuras flexo-activas, que recientemente han atraído considerable atención como nuevo paradigma para construir estructuras ligeras, tanto en el ámbito de la investigación como en la práctica.
El término "flexión activa" hace referencia a una categoría de estructuras en las que la flexión se emplea en el proceso de configuración de su forma. Los sistemas estructurales flexo-activos incluyen barras o láminas incurvadas cuya geometría es el resultado de su deformación elástica desde una configuración inicial recta o plana. Hasta el momento, el número de realizaciones es limitado; se trata sobre todo de aplicaciones experimentales con funcionalidad arquitectónica o artística. La obtención de la configuración de equilibrio es una de las principales dificultades que aparecen en la fase de concepción, debido precisamente a la no linealidad de la respuesta estructural de las barras activas, así como a la posible interacción con otros elementos estructurales como membranas o cables, que trabajan por forma, y cuya geometría no se puede fijar de modo arbitrario. Los métodos computaciones de determinación de forma para estructuras flexo-activas incluyen modelos de elementos finitos con cables virtuales no lineales que se acortan hasta alcanzar la configuración final, o algoritmos de relajación dinámica que consideran las variables que caracterizan la deformación de las barras activas.
Esta tesis doctoral tiene por objeto proporcionar un análisis en profundidad de la aplicabilidad del principio de flexión activa al diseño de estructuras ligeras, en particular a los puentes peatonales. Para ello, la investigación se aborda desde tres puntos de vista: a) modelización computacional; b) eficiencia estructural; c) diseño y construcción. En primer lugar, se lleva a cabo una revisión de la bibliografía existente, haciendo hincapié en los trabajos previos en el diseño de pasarelas con flexión activa. En el campo de la modelización computacional, se desarrolla un novedoso método numérico de determinación de forma para estructuras flexo-activas basado en el modelo geométricamente exacto para piezas alargadas (también conocido como la teoría de vigas de Reissner-Simó). Distintos ejemplos numéricos han sido reproducidos para mostrar la exactitud del método. La parte de la investigación relacionada con el análisis de la eficiencia estructural se centra en el comportamiento del sistema flexo-activo propuesto en esta tesis para el diseño de estructuras ligeras: el arco flexo-activo arriostrado (o atirantado). Se trata de un arco plano compuesto por una barra flexible y continuo que se activa por la acción de los cables principales que tiran de ambos extremos de la varilla, y de los puntales o cables secundarios que desvían el cable principal y actúan en ciertas secciones transversales. La parte computacional-analítica se completa con el desarrollo de un procedimiento numérico basado en algoritmos genéticos, con el fin de obtener configuraciones estructurales eficientes. La tesis finaliza con el diseño, fabricación y montaje de una pasarela flexo-activa hecha con tubos PRFV utilizando este tipo estructural, realizada en el laboratorio de modelos de la Universitat Politècnica de València.[CA] Hui dia, l'arquitectura moderna està orientada principalment a l'ús eficient de materials tecnològics i sostenibles, la tecnificació del procés de disseny, projecte i construcció, i la cerca de solucions molt lleugeres. Aquestes idees es reflecteixen en les estructures flexo-actives, que recentment han atret considerable atenció com a nou paradigma per a construir estructures lleugeres, tant en l'àmbit de la investigació com en la pràctica. El terme "flexió activa" fa referència a una categoria d'estructures en les quals la flexió s'empra en el procés de configuració de la seua forma. Els sistemes estructurals flexo-actius inclouen barres o làmines incorbades, la geometria de les quals és el resultat de la seua deformació elàstica des d'una configuració inicial recta o plana. Fins al moment, el nombre de realitzacions és limitat; es tracta sobretot d'aplicacions experimentals amb funcionalitat arquitectònica o artística. L'obtenció de la configuració d'equilibri és una de les principals dificultats que apareixen en la fase de concepció, degut precisament a la no linealitat de la resposta estructural de les barres actives, així com a la possible interacció amb altres elements estructurals com a membranes o cables, que treballen per forma, i la geometria de la qual no es pot fixar de manera arbitrària. Els mètodes computacions de determinació de forma per a estructures flexo-actives inclouen models d'elements finits amb cables virtuals no lineals que s'escurcen fins a aconseguir la configuració final, o algorismes de relaxació dinàmica que consideren les variables que caracteritzen la deformació de les barres actives. Aquesta tesi doctoral té per objecte proporcionar una anàlisi en profunditat de l'aplicabilitat del principi de flexió activa al disseny d'estructures lleugeres, en particular als ponts per als vianants. Per a això, la investigació s'aborda des de tres punts de vista: a) modelització computacional; b) eficiència estructural; c) disseny i construcció. En primer lloc, es duu a terme una revisió de la bibliografia existent, amb recalcament en els treballs previs en el disseny de passarel·les amb flexió activa. En el camp de la modelització computacional, es desenvolupa un nou mètode numèric de determinació de forma per a estructures flexo-actives basat en el model geomètricament exacte per a peces allargades (també conegut com la teoria de bigues de Reissner-Simó). Diferents exemples numèrics han sigut reproduïts per a mostrar l'exactitud del mètode. La part de la investigació relacionada amb l'anàlisi de l'eficiència estructural se centra en el comportament del sistema flexo-actiu proposat en aquesta tesi doctoral per al disseny d'estructures lleugeres: l' arc flexo-actiu esbiaixat (o lligat). Es tracta d'un arc pla compost per un membre flexible i continu que s'activa per l'acció dels cables principals que tiren de tots dos extrems de la vareta, i dels puntals o cables secundaris que desvien el cable principal i actuen en certa secció transversal de la vareta. La part computacional-analítica es completa amb el desenvolupament d'un procediment numèric basat en algorismes de tipus genètic, amb la finalitat d'obtindre configuracions estructurals eficients. La tesi finalitza amb el disseny, fabricació i muntatge d'una passarel·la flexo-activa feta amb tubs PRFV utilitzant aquest tipus estructural, realitzada en el laboratori de models de la Universitat Politècnica de València.
[EN] Nowadays, modern architecture is focused on the search of efficient uses of technological and sustainable materials, high-tech concept-design-erection processes and the possibility to produce lightweight solutions with maximum elegance in shape. These ideas are reflected on bending-active structures, which recently attracted considerable attention as a new paradigm to build lightweight structures both in research and practice. The concept 'active bending' refers to a category of structures in which bending is used in the process of shape configuration. Bending-active structural systems include curved rods or shells which have been elastically bent from an initial straight or plane configuration. As of now, the number of realisations is limited; they are mostly experimental ones, with architectural or artistic nature. Form finding of the equilibrium configuration is one of the main difficulties during the conceptual phase, due to the non-linearity of the structural response of the active members, and also to the interaction with other form-active structural elements as membranes or cables, whose geometry cannot be prescribed in advance. Computational form-finding methods for bending-active structures include finite element models with non-linear virtual links that are shortened to reach the final form, or dynamic relaxation (explicit) algorithms to cope with the variables describing the response of the active members. This PhD thesis aims to provide an indepth analysis on the applicability of the active bending principle to the design of lightweight structures, in particular pedestrian bridges. For that purpose, the work is carried out from three points of view: (a) computational modelling and simulation; (b) structural performance and efficiency; (c) design and construction. First of all, a literature review on the topic and a overview of realisations in the fied of bending-active footbridges is provided. In the field of computational modelling, a novel form-finding method based on the geometrically exact rod model (or Reissner-Simo beam theory) is implemented. Numerical examples are also given to show the accuracy of the method. The part of the work related to the analysis of the structural performance and efficiency is focused on the bending-active configuration proposed in this PhD thesis for designing lightweight structures: the bending-active braced (or tied) arch. This is a simple planar arch composed of a continuous flexible member that is activated by the action of main cables pulling at both ends of the rod, and secondary struts or cables that deviate the main cable and act at certain cross-section of the rod. The computational-analytical part is completed with the development of a numerical procedure based on genetic algorithms to obtain efficient structural configurations. The thesis ends with the design, fabrication and assembling of a bending-active short footbridge made of GFRP tubes using this structural type, held in the laboratory of concept models of the Polytechnic University of Valencia.
The author has had the opportunity to join the research project: Sistemas estructuras flexo-activos- Concepción, desarrollo y análisis de nuevos prototipos (FLEXACT - grant BIA2105-69330- P)
Bessini Muñoz, JG. (2021). Form-finding and Performance of Bending-active Structures. Proposals of Application to Lightweight Braced Arches [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/165575
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Bergmiller, Gary G. "Lean manufacturers transcendence to green manufacturing : correlating the diffusion of lean and green manufacturing systems." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001847.
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Meisenhelder-Smith, Jodee. "The effects of American Diabetes Association (ADA) diabetes self-management education and continuous glucose monitoring on diabetes health beliefs, behaviors and metabolic control." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001837.
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Doublet, Laurent. "Contribution à l'étude de l'arc électrique et de ses interactions avec les matériaux de contact sous 42 volts DC pour applications automobiles." Rennes 1, 2004. http://www.theses.fr/2004REN10040.
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Pour satisfaire la demande croissante en puissance électrique dans l'automobile, la tension va évoluer de 14 à 42 VDC. Cela implique que les dispositifs de coupure du courant vont devoir s'adapter pour conserver leur fiabilité. Aussi, la compréhension de l'arc et de ses interactions avec les contacts sous 14 VDC doit être étendue au 42 VDC. Cette étude sur l'arc d'ouverture et de fermeture sous 42 VDC nous montre que, par rapport au 14 VDC, la longueur de l'arc est rallongée d'un facteur 10, modifiant l'érosion cathodique en érosion bilatérale. De même, l'arc de fermeture persiste pendant toute la durée du rebond engendrant la soudure des contacts au début de l'arc et à la fin. Enfin, cette modification des mécanismes de transfert conduit à des comportements différents entre matériaux. Seul l'utilisation conjointe de dispositifs complémentaires de réduction d'arc et de matériaux plus adaptés assurera une coupure fiable des arcs sous 42 VDC.
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Gishe, Jemal Emina. "A finite family of q-orthogonal polynomials and resultants of Chebyshev polynomials." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001620.
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Bowers, Robert D. "Evaluation Assessment of Metropolitan Ministries “Uplift U™” Program and Preliminary Analysis of Collected Data." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1577.
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Using the methodology and criteria put forth by the Juvenile Justice Evaluation Center (part of the Justice Research and Statistics Association, Washington D.C.), an assessment for evaluation of the Metropolitan Ministries "Uplift UTM" Program was conducted using review of data previously collected by Metropolitan Ministries, examination of documents provided by the organization, participant observation, and interviews with Metropolitan Ministry staff. This assessment reveals that there are significant problems in several areas that must be addressed before their program can be formally evaluated; including data collection and organization, outcomes measures, client selection standards, and how the program is portrayed as opposed to how it is actually run. Preliminary analysis of the collected data suggests that there are no relationships between demographic information such as education, employability, or other factors, and successfully completing their program. Further analysis suggests that other factors related to rules, guidelines, and unpopular restrictions are related to the low success rate they have experienced. Based upon a literature review of successful programs, suggestions for improving the outcomes of Uplift UTM are provided.
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Ye, Xin. "Development of models for understanding causal relationships among activity and travel variables." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001842.
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Ross, Alexandra C. M. "Continuous curatorial conversations : an exploration of the role of conversation within the writing of a supplementary history of the curatorial." Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/af610c50-f15e-43f0-8801-2b07defff126.
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Continuous Curatorial Conversations is a practice-led exploration of conversation, both as a medium and as a tool for capturing supplementary histories of the curatorial. The primary question of this research project is how the medium of conversation can be explored to write supplementary histories of the curatorial which thus far have been omitted from extant publications on the subject. Three important sub questions guide this exploration. First, what is and has been the role of conversation within the curatorial? What are the possibilities and limitations within the medium of conversation? What roles do conviviality and hospitality play within the process of conversation? This thesis reflects upon a series of curated projects that explore the sp/pl/ace for curatorial conversation and also reviews a collection of one-to-one recorded conversations conducted by the author, including conversations with Alfredo Cramerotti, Hedwig Fijen, Mel Gooding, William Furlong and Sarah Lowndes. Sites of fieldwork include: the 54th Venice Biennale; Manifesta 8, The European Biennial of Contemporary Art; and Glasgow International Festival of Visual Art 2012. Through these projects and related recordings it unpicks the norms and possibilities of what and when one can record on the subject of the curatorial. The hypothesis of this study is that a great deal of curatorial activity is locked up in conversation, yet a disproportion makes it to the pages of the history of the field. Furthermore, in its clean transcribed form it misrepresents the fragility and nuance of the original exchange. The theoretical context of this research looks at Nicolas Bourriaud’s notion of Relational Aesthetics, the writing of Maria Lind and Paul O’Neill, with a focus on Audio Arts. A new methodology relating to curatorial conversation and its recording has therefore been identified as ‘critical conviviality’. The writing relating to Continuous Curatorial Conversations research takes the form of four books. The book ‘An Introduction’ comprises the PhD thesis and sits next to a bespoke online platform www.continuous-curatorial-conversations.org which hosts a selection of audio recordings collated during the research process. The books ‘Continuous’, ‘Curatorial’, and ‘Conversations’ unpack the lineage and context of Alexandra C.M. Ross’s practice and projects conducted during her research and are to be read in no strict order. The new knowledge resulting from this thesis and relating practice is the attention to the subtleties of conversation and its capture as it relates to the instigation, recording and presentation of semi-private matters in semi-public contexts.
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Dallaire, Frédéric. "Création sonore et cinéma contemporain : la pensée et la pratique du mixage." Thèse, Paris 10, 2014. http://hdl.handle.net/1866/11587.
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Notre thèse décrit et analyse les conditions esthétiques, matérielles et idéelles qui rendent possibles les agencements sonores du cinéma contemporain. Au cours des 30 dernières années, le raffinement des outils de manipulation du son, l’importance grandissante du concepteur sonore et le nouvel espace de cohabitation des sons (favorisé par le Dolby et la diffusion multicanal) sont des facteurs qui ont transformé la création et l’écoute du son au cinéma. Ces transformations révèlent un nouveau paradigme : le mixage s’est graduellement imposé comme le geste perceptif et créateur qui rend compte de la sensibilité contemporaine. Notre thèse explore les effets de la pensée du mixage (qui procède par résonance, simultanéité, dosage et modulation) sur notre écoute et notre compréhension de l'expérience cinématographique. À l'aide de paroles de concepteurs sonores (Murch, Beaugrand, Thom, Allard…), de textes théoriques sur le son filmique (Cardinal, Chion, Campan), de documentaires sur des musiciens improvisateurs (Lussier, Glennie, Frith), de films de fiction à la dimension sonore affirmée (Denis, Van Sant), de textes philosophiques sur la perception (Leibniz, James, Straus, Szendy…), d'analyses du dispositif sonore cinématographique, notre thèse rend audibles des tensions, des récurrences, de nouveaux agencements, des problèmes actuels et inactuels qui forgent et orientent l'écoute du théoricien, du créateur et de l'auditeur. En interrogeant la dimension sonore de la perception, de l’action, de l’espace et de la pensée, cette thèse a pour objectif de modifier la façon dont on écoute, crée et pense le son au cinéma.This thesis describes and analyzes the esthetic, material and conceptual conditions that make the acoustic structures of contemporary cinema possible. The refinement of tools used for manipulating sound, the growing importance the sound designer and the emergence of a new space for sounds to coexist in (brought on by Dolby and multichannel sound systems) are factors that, over the past 30 years, have transformed the way we work with and listen to sound in film. These transformations reveal a new paradigm: mixing gradually imposed itself as the creative and perceptual act capable of accounting for our contemporary sensibility. This thesis explores the effects of the “thought process of mixing” (which functions by resonance, simultaneity, dosage and modulation) on the way we hear and understand the cinematographic experience. Working from the accounts of sound designers (Murch, Beaugrand, Thom Allard…), theoretical texts on film sound (Cardinal, Chion, Campam), documentaries on improvisational musicians (Lussier, Glennie, Frith), fiction films with a acute acoustic sensibility (Denis, Van Sant), philosophical texts on perception (Leibniz, James, Straus, Szendy…) and analyses of the cinematographic sound apparatus, this thesis renders audible the tensions, the recurrences, the structural connections and the problems, old and new, that forge and direct the theoretician, the artist and the auditor’s way of listening. By questioning the auditory dimension of perception, action, space and thought, this thesis aims to change the way we hear, create and think cinema.
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Shi, Zhen. "Heme biosynthesis: structure-activity studies of murine ferrochelatase." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001450.
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Nuruddin, Ibrahim K. "Effect of welding thermal cycles on the heat affected zone microstructure and toughness of multi-pass welded pipeline steels." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7755.
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This research is aimed at understanding the effect of thermal cycles on the metallurgical and microstructural characteristics of the heat affected zone of a multi-pass pipeline weld. Continuous Cooling Transformation (CCT) diagrams of the pipeline steel grades studied (X65, X70 and X100) were generated using a thermo mechanical simulator (Gleeble 3500) and 10 mm diameter by 100 mm length samples. The volume change during phase transformation was studied by a dilatometer, this is to understand the thermodynamics and kinetics of phase formation when subjected to such varying cooling rates. Samples were heated rapidly at a rate of 400°C/s and the cooling rates were varied between t8/5 of 5.34°C/s to 1000°C/s. The transformation lines were identified using the dilatometric data, metallographic analysis and the micro hardness of the heat treated samples. Two welding processes, submerged arc welding (SAW) and tandem Metal Inert Gas (MIG) Welding, with vastly different heat inputs were studied. An API-5L grades X65, X70 and X100 pipeline steels with a narrow groove bevel were experimented with both welding processes. The welding thermal cycles during multi-pass welding were recorded using thermocouples. The microstructural characteristics and metallurgical phase formation was studied and correlated with the fracture toughness behaviour as determined through the Crack Tip Opening Displacement (CTOD) tests on the welded specimens. It was observed that SAW process is more susceptible to generate undesirable martensite-austenite (M-A) phase which induce formation of localised brittle zones (LBZ) which can adversely affect the CTOD performance. Superimposition of the multiple thermal cycles, measured in-situ from the different welding processes on the derived CCTs, helped in understanding the mechanism of formation of localised brittle zones. Charpy impact samples were machined from the two X65 and X70 grades, for use in thermal simulation experiments using thermo mechanical simulator (Gleeble). The real thermal cycles recorded from the HAZ of the SAW were used for the thermal simulations, in terms of heating and cooling rates. This is to reproduce the microstructures of the welds HAZ in bulk on a charpy impact sample which was used for impact toughness testing, hardness and metallurgical characterisation. The three materials used were showing different response in terms of the applied thermal cycles and the corresponding toughness behaviours. The X65 (a) i.e. the seamless pipe was showing a complete loss of toughness when subjected to the single, double and triple thermal cycles, while the X65 (b), which is a TMCP material was showing excellent toughness in most cases when subjected to the same thermal cycles at different test temperatures. The X70 TMCP as well was showing a loss of toughness as compared to the X65 (b). From the continuous cooling transformation diagrams and the thermally simulated samples results it could be established that different materials subjected to similar thermal cycle can produce different metallurgical phases depending on the composition, processing route and the starting microstructure.
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Camden, Jacquelynn. "The Voice of Ritual: A Pedagogical Exploration Teaching Body and Breath Using the Principles of Ritual Poetic Drama within the African Continuum." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2754.
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THE VOICE OF RITUAL: AN EXPLORATION TEACHING BODY AND BREATH USING THE PEDAGOGICAL PRINCIPLES OF RITUAL POETIC DRAMA WITHIN THE AFRICAN CONTINUUM By Jacquelynn Rae Camden, MFA Candidate A thesis submitted in partial fulfillment of the requirements for the degree of Master of Fine Arts Theatre Pedagogy: Voice and Speech & Ritual Poetic Drama Within the African Continuum at Virginia Commonwealth University. Virginia Commonwealth University, 2012 Major Director: Dr. Tawnya Pettiford-Wates, Theatre The focus of my undergraduate training and the concentration of my graduate work have been specifically in two areas: Ritual Poetic Drama Within the African Continuum under the tutelage of Dr. Tawnya Pettiford-Wates, and Voice and Speech with Janet B. Rodgers. I spent my undergraduate years learning and absorbing the material and philosophy of both Rodgers and Pettiford-Wates, and in my first year of graduate work, I was able to study their teaching principles and methodologies within the classroom as a teaching assistant. I was also fortunate enough to study the teaching principles of fellow graduate students within both concentrations: Ritual Poetic Drama Within the African Continuum and Voice & Speech. It is my intention with this thesis, to explain how and why I decided to integrate some of the teaching methodologies of RPDWTAC into the Second Year Voice & Speech course I taught in the fall of 2010, which focused on body and breath. It is my belief that these particular practices of Ritual Poetic Drama within the African Continuum as applied to the Junior Acting Studio are also beneficial in the pedagogy of Voice and Speech in the classroom, because such practices create an environment that encourages the building of an artistic community, personal responsibility, and the freeing of the artist’s body, mind, and spirit, resulting in the freeing of the voice as well.
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Vidales, Luna Benjamin. "Architecture de convertisseur intégrant une détection de défauts d'arcs électriques appliquée au sources d'énergie continues d'origine photovoltaïques." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0040.
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Détection de défaut d'arcs intégrée dans un convertisseur intelligent contrôlé par FPGA pour les panneaux photovoltaïques. La mise au point de convertisseur intelligents intégrant des dispositifs de protection est une thématique que cherche à développer l'Institut Technologique de Morelia (Mexique) avec laquelle nous collaborons sur ce projet. L'objectif plus spécifique de ce travail repose sur la détection de défauts d'arc électrique en se basant sur le contrôle intelligent des onduleurs utilisés dans la gestion de l'énergie produite par des panneaux photovoltaïques. Depuis plusieurs années, le développement croissant des panneaux solaires photovoltaïques comme source d’énergie s’est imposé et la sécurité de ces dispositifs liée à la détection de défauts d’arcs électriques est devenu un enjeu majeur. L'approche que nous proposons dans ce travail est le développement d'une stratégie novatrice pour la surveillance et la prédiction de défaillance du réseau électrique constitué de panneaux solaires en présence de défauts d’arcs. Actuellement, la majorité des systèmes de détection comprennent des modules détecteurs disposés dans le circuit électrique à protéger dont la robustesse est loin d'être optimale. L'approche que nous proposons consiste à développer un dispositif de surveillance et de détection de défaut directement intégré dans l'onduleur intelligent. Le contrôle optimal de l'onduleur intelligent assurera une détection fiable de défaut d'arc sans déclenchement intempestif. Le dispositif comprendra également un système de coupure. La méthode de détection que nous privilégions sera basée sur l'analyse du courant et de la tension de ligne. Les algorithmes seront basés sur une analyse temps/fréquence des signatures courant et de tension suivie par une logique pertinente de décision de telle manière à minimiser le taux de fausses détections.Le noyau du convertisseur intelligent est constitué par un FPGA. Le parallélisme des traitements de données assurera le respect des contraintes temps réel. Dans le cadre du projet de thèse, la mise en œuvre, le test des algorithmes de détection et l’implémentation optimale afin de respecter les contraintes temps réel dans le FPGA sera mené dans le cadre d’une cotutelle de thèse entre l’institut technologique de Morelia et l’Université de LorraineIn this research work, the development of a multilevel inverter for PV applications is presented. The PV inverter, has two stages one DC/DC converter and one DC/AC inverter, and is capable of generating an AC multilevel output of nine levels, it's a transformerless inverter and uses a reduced number of components compared to other topologies. The conception of a novel DC/DC converter is capable of generating two isolated DC voltage levels needed to feed the DC/AC stage. This DC/DC stage is developed in two variants, buck and boost, the _rst to perform the reduction of voltage when the DC bus is too high, and second to increase the voltage when the DC bus is too low to perform interconnection with the grid through the DC/AC inverter. This is achieved thanks to the parallel functioning of the developed topology, which make use of moderated duty cycles, that reduces the stress in the passive and switching components, reducing potential losses. The validation of the PV inverter is performed in simulation and experimental scenarios. In the other hand, the response of the inverter facing an arc fault in the DC bus is studied by performing a series of tests where the fault is generated in strategic points of the DC side, this is possible thanks to the design and construction of an arc fault generator based in the specifications of the UL1699B norm. During the tests is observed that with the apparition of an arc fault, there is a lost in the half-wave symmetry of the AC multilevel output voltage waveform, generating even harmonics which aren't present during normal operation, only when an arc fault is present in the DC system. The monitoring of even harmonics set the direction for developing the detection technique. Since the magnitude of even harmonics in the inverter is very low, the total even harmonic distortion is employed as a base for the detection technique presented in this thesis. The effectiveness of this method is verified with a series of tests performed with different loads
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Davis, Justin Sean. "The Development of Leibniz’s Substance Ontology From 1666-1688." Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3927.
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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.
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Robinson, Raymond Stanley. "Dreaming tracks : history of the Aboriginal Islander Skills Development Scheme, 1972-1979 : its place in the continuum." Thesis, View thesis View thesis, 2000. http://handle.uws.edu.au:8081/1959.7/76.
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Dreaming Tracks was chosen for the title of this history because of its reference to the journeys and routes taken by the ancestral founders of each of the extended family clans. As they travelled they recorded the events and situations they encountered along the way , which they left in story, painting, song lines and dances for the future survival of their people. The history of the Aboriginal/Islander Skills Development Scheme also pertains to a journey. This journey records the events that brought about the establishment of the longest surviving, urban Indigenous dance organization. It's a voyage that identifies the obstacles and accomplishments of its founding members, who dedicated themselves to the hard work to ensure the continuum of Aboriginal and Torres Strait Islander dance. It was their dream, to have an Australian Black Dance Company that would create a link between past and present, traditional and urban. The pathways they created equipped urban Indigenous Australians with a unique dance identity of their own, and established the path to continued contact with the traditional owners. Dreaming Tracks is contemporary Dreaming lore that begins with the contention for land rights in the early 1970's and follows the progress of the Aboriginal/Islander Skills Development Scheme to the end of the decade. It records the desires, dreams and conflicts that brought this organization into being. In parallel, the concerns of the founder, Carole Y. Johnson, sets the path for the journey, which by the end of the twentieth-century witnessed the establishment of an accredited dance course, two dance companies (The Aboriginal/Islander Dance Theatre and Bangarra Dance Theatre, Australia) and students who are key participants in the artistic design of the 2000 Olympics in Sydney Australia
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Rouffet, Marie-Emilie. "Nouvelle méthode de diagnostic optique des plasmas thermiques : application au mélange argon-hydrogène-hélium." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/338/.
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Les plasmas thermiques sont des systèmes complexes utilisés dans de nombreuses applications industrielles. Leurs propriétés intrinsèques et les transferts d'énergie qui s'y déroulent sont de plus en plus étudiés pour la complexité des phénomènes physiques mis en jeu. La température est une des grandeurs particulièrement pertinente à étudier, car elle est d'une part un élément de contrôle du bon déroulement des processus, et d'autre part un paramètre clé dans la connaissance des propriétés des plasmas. Les travaux réalisés ont consisté à développer une nouvelle technique de mesure simple et fiable de la température d'un plasma, qui puisse s'appliquer rapidement sur des réacteurs à plasmas industriels. Nous avons restreint notre étude au mélange Ar-H2-He. Dans un premier temps, le rayonnement théorique du plasma a été calculé. Pour cela, nous avons considéré d'une part le fond continu, et d'autre part les raies. Pour des températures comprises entre 5 kK et 30 kK, les calculs radiatifs de 30 nm à 4500 nm ont permis d'établir une base de données théoriques servant de point de départ pour la réalisation pratique de l'étude. En parallèle, un dispositif expérimental a été développé, avec la mise en place d'un arc stabilisé par paroi. Les émissivités du plasma ont été recueillies par spectroscopie d'émission pour des arcs établis dans l'argon pur et dans les mélanges Ar-H2. Une comparaison des valeurs expérimentales et théoriques a permis de déterminer la température du plasma. L'évaluation de cette température par des techniques classiques de spectroscopie d'émission a complété la validation de notre nouvelle méthode de diagnosticThermal plasma temperature is a key parameter in the study of intrinsic properties as well as in the control and optimization of industrial processes. To determine the temperature, emission spectroscopy is often used because the intensity of the plasma radiation changes strongly according to its temperature. A new diagnostic method to evaluate thermal plasma temperature is investigated. Both simple and reliable, this technique can fast be applied on industrial reactors. This method in principle consists of using the relative and absolute dependencies on temperature of the emitted plasma radiation in various spectral regions. The technique needs a preliminary study to calculate these relations. So the theoretical plasma radiation was calculated. We have considered the continuum, by paying a particular attention in atomic and molecular contributions, and the lines, by taking into account the absorption. Radiative calculations are allowed to establish a base of theoretical data, from 30 nm to 4500 nm and 5 kK to 30 kK, for Ar-H2-He plasma mixtures at atmospheric pressure. An experimental study was carried out to validate the methods. The set-up is composed of a wall-stabilized arc and a multichannel spectrometer. Values of temperature o btained by the new method are compared with literature and the classical measurements based on absolute line intensity method. We limit to work in pure argon and Ar-H2 mixture. Experimental results are presented and discussed
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LIEUTIER, MICHEL. "Etude experimentale de la coupure d'un courant continu par mise en oscillation de l'arc electrique." Clermont-Ferrand 2, 1990. http://www.theses.fr/1990CLF2D221.
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Cette these decrit un procede de mise en oscillation de l'arc afin de creer un zero de courant dans un appareil de coupure. Il utilise, en parallele sur un contacteur, un circuit oscillant lc de commutation et une varistance. Des la separation des contacts, l'oscillation de l'arc peut etre croissante et provoquer un passage par zero. Le courant de ligne est alors derive dans la capacite puis dans la varistance ou l'energie du systeme se dissipe. Le dispositif experimental met en uvre: un capteur destine a extraire la tension d'arc (<200 v) de la tension atteinte aux bornes du contacteur (>1000 v); une matrice de vingt fibres optiques qui permet de determiner la geometrie de l'arc; un systeme de fibres fluorescentes qui mesure son intensite lumineuse. Dans la gamme de tension exploree (jusqu'a 450 v), on peut tirer les conclusions suivantes: la coupure des courants inductifs (<20 a) est realisee avec des durees d'arc tres faibles (quelques ms); l'arc, au cours des oscillations conduisant au zero, reste entre les contacts; le courant d'arc et son intensite lumineuse sont proportionnels. Par rapport a la technique classique de soufflage dans une chambre, qui engendre des durees d'arc importantes (plusieurs dizaines de ms), l'utilisation d'un circuit de commutation permet donc de reduire l'usure des contacts et les dimensions de l'appareil de coupure. Une modelisation du circuit, a partir de l'equation de mayr, permet de simuler l'evolution du courant dans l'interrupteur
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Fouque, Aurélien. "Contribution à l'étude du couplage thermique-mécanique-électrique dans les contacts électriques : application à l'élaboration d'un modèle de durée de vie d'un contacteur." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASC001.
Full textAbstract:
Un contacteur est un dispositif électromécanique destiné à établir ou couper un courantélectrique dans un circuit par la fermeture ou l’ouverture de contacts. Lors de chaquemanœuvre, un arc électrique est créé entre les «pastilles» des contacts, conduisant parl’énorme densité de puissance mise en jeu à atteindre et dépasser localement la températurede fusion du matériau. De ce fait, l’action répétée des arcs durant la vie de l’appareil (jusqu’àplusieurs centaines de milliers de cycles ouverture/fermeture) mène progressivement à la«ruine» des pastilles des contacts et au dysfonctionnement du contacteur. Le travail de thèsevise à proposer des outils de modélisation de l’endommagement des pastilles de contact sousl’effet des arcs, dans l’objectif à plus long terme de prédire la durée de vie du contacteurselon ses conditions d’utilisation. Le matériau considéré est un pseudo-alliage en argent etoxyde d’étain. Dans un premier temps, plusieurs campagnes expérimentales ont été menéespour réunir toutes les données d’entrée indispensables aux modélisations : déterminationdes propriétés thermomécaniques du matériau, caractérisation des endommagements – ensurface et en profondeur – produits par un arc unique et par une accumulation d’arcs,estimation de la densité de puissance apportée par un arc au matériau de contact. Denombreuses techniques ont ainsi été mises en œuvre : essais de traction monotone et dechargement cyclique, indentation (microdureté), profilométrie 3D, microscopies optiqueet électronique à balayage, analyses EDS et EBSD, imagerie par caméras thermique etultrarapide. Puis deux types de modèles ont été successivement développés. Le premierutilise le code de calcul par éléments finis Zset. Développé en géométrie axisymétrique, ilvise à décrire au sein du matériau l’évolution des températures, contraintes et déformationsrésultant d’un arc (supposé fixe), puis l’amorçage de fissures au terme de quelques centainesd’impacts au même point. Une variante 3D a ensuite été abordée pour approcher le casd’arcs mobiles. Le second modèle, de nature phénoménologique, repose sur des descriptionssimplifiées de la topographie et de la teneur en argent au voisinage de la surface, ainsique sur des règles d’occurrence et de distribution spatiale, issues autant que possible desobservations expérimentales. Il est destiné à simuler dans un temps de calcul raisonnableles dommages résultant du cumul d’un très grand nombre d’arcs sur toute la surface despastillesA contactor is an electromechanical device designed to establish or disconnect anelectrical current in a circuit by closing or opening contacts. During each operation, anelectric arc is created, due to the enormous power density involved to reach and locallyexceed the melting temperature of the material. As a result, the repeated action of thearcs during the life of the device (up to several hundred thousand closing/opening cycles)gradually leads to the ruin of the contact pads and the malfunction of the contactor. Thethesis work aims to propose tools for modelling the damage of contact pads under the effectof repeated impacts, with the longer-term objective of predicting the life of the contactoraccording to its operating conditions. The material considered is a pseudo-alloy made ofsilver and tin oxide SnO 2 . As a first step, several experimental campaigns were carried outto collect all the input data required for modelling : determination of the thermomechanicalproperties of the material, characterization of damage – surface and bulk – produced by asingle arc and by an accumulation of arcs, estimation of the power density provided by anarc to the contact material. Many experimental techniques have been used : monotonoustensile tests and cyclic loading, indentation (microhardness), 3D profilometry, opticalmicroscopy and scanning electron microscopy, EDS and EBSD analysis, thermal imagingcamera, high speed camera. Then two types of models were successively developed. Thefirst one uses the Zset finite element code. Developped in an axisymmetric geometry, itaims to describe within the material the evolution of temperatures, stresses and strainsresulting from an arc (assumed fixed), then the initiation of cracks after a few hundredof impacts at the same point. A 3D variant was then discussed to approach the case ofmoving arcs. The second model, of a phenomenological nature, is based on simplifieddescriptions of topography and tensile strength in silver in the vicinity of the surface, aswell as on rules of occurrence and spatial distribution, taken as much as possible fromexperimental observations. It is intended to simulate in a manageable calculation time thedamage resulting from the accumulation of a very large number of arcs over the entiresurface of the pellets