• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 76
  • 46
  • 17
  • 16
  • 15
  • 6
  • 6
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 224
  • 47
  • 45
  • 27
  • 18
  • 15
  • 15
  • 14
  • 13
  • 12
  • 11
  • 11
  • 11
  • 11
  • 10
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Ariadne’s Thread - memory, interconnection and the poetic in contemporary art

Fries, Katherine January 2008 (has links)
Master of Visual Arts / This Dissertation explores the metaphor of Ariadne’s thread in terms of interconnection, when an element from the everyday is used as a locus linking broader concepts of time and space. Such experiences and associations are reflected in the work of Louise Bourgeois, Eva Hesse, Doris Salcedo, Lucio Fontana, Richard Tuttle, Mona Hatoum, Simone Mangos, Anya Gallaccio and Yoshihiro Suda. In relation to my own work, the metaphor of interconnecting thread allows a sense of freedom and journey of discovery. My studio and related research are closely aligned in developing my understanding of interconnection, through my studio process of making and continuing experiences of looking at and interpreting others artists’ work.
222

The Hair Bundle: Fluid-Structure Interaction in the Inner Ear

Baumgart, Johannes 08 November 2010 (has links)
A multitude of processes cooperate to produce the sensation of sound. The key initial step, the transformation from mechanical motion into an electrical signal, takes place in highly specialized mechanosensitive organelles that are called hair bundles due to their characteristic appearance. Each hair bundle comprises many apposed cylindrical stereocilia that are located in a liquid-filled compartment of the inner ear. The viscous liquid surrounding the hair bundle dissipates energy and dampens oscillations, which poses a fundamental physical challenge to the high sensitivity and sharp frequency selectivity of hearing. To understand the structure-function relationship in this complex system, a realistic physical model of the hair bundle with an appropriate representation of the fluid-structure interactions is needed to identify the relevant physical effects. In this work a novel approach is introduced to analyze the mechanics of the fluid-structure interaction problem in the inner ear. Because the motions during normal mechanotransduction are much smaller than the geometrical scales, a unified linear system of equations describes with sufficient accuracy the behavior of the liquid and solid in terms of a displacement variable. The finite-element method is employed to solve this system of partial differential equations. Based on data from the hair bundle of the bullfrog's sacculus, a detailed model is constructed that resolves simultaneously the interaction with the surrounding liquid as well as the coupling liquid in the narrow gaps between the individual stereocilia. The experimental data are from high-resolution interferometric measurements at physiologically relevant amplitudes in the range from a fraction of a nanometer to several tens of nanometers and over a broad range of frequencies from one millihertz to hundred kilohertz. Different modes of motion are analyzed and their induced viscous drag is calculated. The investigation reveals that grouping stereocilia in a bundle dramatically reduces the total drag as compared to the sum of the drags on individual stereocilia moving in isolation. The stereocilia in a hair bundle are interconnected by oblique tip links that transmit the energy in a sound to the mechanotransduction channels and by horizontal top connectors that provide elastic coupling between adjacent stereocilia. During hair-bundle deflections, the tip links induce additional drag by causing small but very dissipative relative motions between stereocilia; this effect is offset by the horizontal top connectors that restrain such relative movements, assuring that the hair bundle moves as a unit and keeping the total drag low. In the model the stiffness of the links, the stiffness of the stereocilia, and the geometry are carefully adjusted to match experimental observations. The references are stiffness and drag measurements, as well as the coherence measurements for the bundle's opposite edges, both with and without the tip links. The results are further validated by a comparison with the relative motions measured in a sinusoidally stimulated bundle for the distortion frequencies at which movements are induced by the nonlinearity imposed by channel gating. The model of the fluid-structure interactions described here provides insight into the key step in the perception of sound and the method presented provides an efficient and reliable approach to fluid-structure interaction problems at small amplitudes. / Bei der Hörwahrnehmung eines Klangs spielen viele komplexe Prozesse zusammen. Der Schlüsselprozess, die Umwandlung mechanischer Schwingungsbewegung in elektrische Signale, findet in den Haarbündeln im Innenohr statt. Diese Haarbündel sind hoch entwickelte mechanosensitive Organellen, bestehend aus vielen nahe beieinander stehenden Stereozilien umgeben von Flüssigkeit. Die beträchtliche Viskosität dieser Flüssigkeit führt zur Energiedissipation und zur Schwingungsdämpfung, was im Gegensatz zur bekannten hohen Empfindlichkeit und der ausgezeichneten Frequenzselektivität der Hörwahrnehmung steht. Um die Komponenten des Haarbündelsystems in ihrem funktionalen Zusammenspiel besser zu verstehen, bedarf es eines wirklichkeitsgetreuen Modells unter Einbeziehung der Wechselwirkung zwischen Flüssigkeit und Struktur. Mit dieser Arbeit wird ein neuer Ansatz vorgestellt, um die Mechanik der Fluid-Struktur-Wechselwirkung im Innenohr zu analysieren. Da die Bewegungen bei der normalen Mechanotransduktion wesentlich kleiner als die geometrischen Abmessungen sind, ist es möglich, das Verhalten von Fluid und Struktur in Form der Verschiebungsvariable in einem linearen einheitlichen System von Gleichungen ausreichend genau zu beschreiben. Dieses System von partiellen Differentialgleichungen wird mit der Finite-Elemente-Methode gelöst. Basierend auf experimentell ermittelten Daten vom Haarbündel des Ochsenfrosches wird ein detailliertes Modell erstellt, welches sowohl die Interaktion mit der umgebenden Flüssigkeit als auch die koppelnde Flüssigkeit in den engen Spalten zwischen den einzelnen Stereozilien erfasst. Die experimentellen Daten sind Ergebnisse von hochauflösenden interferometrischen Messungen bei physiologisch relevanten Bewegungsamplituden im Bereich von unter einem Nanometer bis zu mehreren Dutzend Nanometern, sowie über einen breiten Frequenzbereich von einem Millihertz bis hundert Kilohertz. Das Modell erlaubt die Berechnung der auftretenden viskosen Widerstände aus der numerischen Analyse der verschiedenen beobachteten Bewegungsmoden. Es kann gezeigt werden, dass durch die Gruppierung zu einem Bündel der Gesamtwiderstand drastisch reduziert ist, im Vergleich zur Summe der Widerstände einzelner Stereozilien, die sich individuell und unabhängig voneinander bewegen. Die einzelnen Stereozilien in einem Haarbündel sind durch elastische Strukturen mechanisch miteinander verbunden: Die Energie des Schalls wird durch schräg angeordnete sogenannte Tiplinks auf die mechanotransduktiven Kanäle übertragen, wohingegen horizontale Querverbindungen die Stereozilien direkt koppeln. Während der Haarbündelauslenkung verursachen die Tiplinks zusätzlichen Widerstand durch stark dissipative Relativbewegungen zwischen den Stereozilien. Die horizontalen Querverbindungen unterdrücken diese Bewegungen und sind dafür verantwortlich, dass sich das Haarbündel als Einheit bewegt und der Gesamtwiderstand gering bleibt. Die Steifigkeit der Stereozilien und der Verbindungselemente sowie deren Geometrie sind in dem Modell sorgfältig angepasst, um eine Übereinstimmung mit den Beobachtungen aus verschiedenen Experimenten zu erzielen. Als Referenz dienen Steifigkeits- und Widerstandsmessungen, sowie Kohärenzmessungen für die gegenüberliegenden Außenkanten des Bündels, die jeweils mit und ohne Tiplinks durchgeführt wurden. Darüberhinaus sind die Ergebnisse durch den Vergleich mit experimentell beobachteten Relativbewegungen validiert, die das Haarbündel infolge von sinusförmiger Anregung bei Distorsionsfrequenzen zeigt. Diese haben ihren Ursprung in dem nichtlinearen Prozess des öffnens von Ionenkanälen. Das entwickelte Modell eines Haarbündels liefert neue Einblicke in den Schlüsselprozess der auditiven Wahrnehmung. Zur Behandlung von Problemen der Fluid-Struktur-Wechselwirkungen bei kleinen Amplituden hat sich der hier ausgearbeitete Ansatz als effizient und zuverlässig erwiesen.
223

"Minds will grow perplexed": The Labyrinthine Short Fiction of Steven Millhauser

Andrews, Chad Michael 25 February 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Steven Millhauser has been recognized for his abilities as both a novelist and a writer of short fiction. Yet, he has evaded definitive categorization because his fiction does not fit into any one category. Millhauser’s fiction has defied clean categorization specifically because of his regular oscillation between the modes of realism and fantasy. Much of Millhauser’s short fiction contains images of labyrinths: wandering narratives that appear to split off or come to a dead end, massive structures of branching, winding paths and complex mysteries that are as deep and impenetrable as the labyrinth itself. This project aims to specifically explore the presence of labyrinthine elements throughout Steven Millhauser’s short fiction. Millhauser’s labyrinths are either described spatially and/or suggested in his narrative form; they are, in other words, spatial and/or discursive. Millhauser’s spatial labyrinths (which I refer to as ‘architecture’ stories) involve the lengthy description of some immense or underground structure. The structures are fantastic in their size and often seem infinite in scale. These labyrinths are quite literal. Millhauser’s discursive labyrinths demonstrate the labyrinthine primarily through a forking, branching and repetitive narrative form. Millhauser’s use of the labyrinth is at once the same and different than preceding generations of short fiction. Postmodern short fiction in the 1960’s and 70’s used labyrinthine elements to draw the reader’s attention to the story’s textuality. Millhauser, too, writes in the experimental/fantastic mode, but to different ends. The devices of metafiction and realism are employed in his short fiction as agents of investigating and expressing two competing visions of reality. Using the ‘tricks’ and techniques of postmodern metafiction in tandem with realistic detail, Steven Millhauser’s labyrinthine fiction adjusts and reapplies the experimental short story to new ends: real-world applications and thematic expression.
224

Rozklad černé, technika nedůsledného překládání Světla / The Breaking Down of Black, the Technique of Inconsistent Transfer of Light

Trnková, Barbora Unknown Date (has links)
Im interested in the topic of praying machine, because I want to analyze aspects of photography and its functions. It's known, that the reality is manipulated by photography. Bud we can also say, that the relationship between reality and photography is neutral in fact, that the manipulation is made by our interpretation of photography. The change of the reality can be realized just in the dialog between photography and reality. Can it be, that the mechanization change into the will? Does it prays praying mill or the buddhistic monk, who rotates the mill? When he believes into it, is it enough? Or is it enough if believes who watch the monk with his mill? ... The computers from he place A are "praying" the prayers from the place B. With Tomáš Javůrek we collaborated with Vladimír Veselý and Radek Lát to create the Game for re-articulation our reality on the base of the revision of our faith.

Page generated in 0.0432 seconds