976 resultados para DIAPHRAGM MAGNETOMETER
Resumo:
The courthouse at El Ejido has a trapezoid floor plan (47 m. x 55 / 26 m.) and comprises two distinct volumes that are structurally connected at basement level and by footbridges on the upper storeys. A third trapezoid unit featuring a glazed curtain wall façade cantilevers 8 m. off the main façade of the front volume. This façade is a structural diaphragm wall, constituted by nine rows of vertical precast concrete members separated by horizontal cast-in-place, self-compacting concrete chords. The location of the courthouse in a seismic area and the short number of horizontal supports for the façade make this wall potentially vulnerable. The particularly high risk during construction called for careful planning based on a detailed analysis of the interaction between the structure and the ancillary resources used to build it
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Numerical simulations of flow surrounding a synthetic jet actuating device are presented. By modifying a dynamic mesh technique available in OpenFoam-a well-documented open-source solver for fluid dynamics, detailed computations of the sinusoidal motion of the synthetic jet diaphragm were possible. Numerical solutions were obtained by solving the two dimensional incompressible viscous N-S equations, with the use of a second order implicit time marching scheme and a central finite volume method for spatial discretization in both streamwise and crossflow directions. A systematic parametric study is reported here, in which the external Reynolds number, the diaphragm amplitude and frequency, and the slot dimensions are varied.
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Esta tesis doctoral, bajo el título “La transformación de la fachada en la arquitectura del siglo XX. Evolución de los elementos arquitectónicos hacia el espacio único”, examina –siguiendo el método deductivo mediante investigación documental y de campo– los principales mecanismos proyectuales que han originado una transformación arquitectónica en la fachada. El término fachada, leído normalmente como sinónimo de arquitectura, ha sido analizado bajo taxonomías historiográficas, sociopolíticas, formales, compositivas o materiales. Más allá de estas clasificaciones, esta investigación determina cómo han evolucionado los elementos arquitectónicos hacia el espacio único, transformando con ello tanto la realidad física como el concepto de fachada. Proyectar, como diría Robert Venturi1. 1966, tanto desde el exterior al interior como desde el interior al exterior, produce las tensiones necesarias que ayudan a generar la arquitectura. De ahí la importancia del estudio de la transformación de la fachada como faccia, máscara, disfraz o sistema de representación, a la fachada como un diafragma activo, como un espacio de relación o como un límite donde se produce una experiencia arquitectónica con nuevos significados. El término fachada, del latín facies y del italiano facciata, fue creado como tal durante el siglo XVI, aunque como elemento arquitectónico es una realidad clásica y un concepto humanista reinventado en el Renacimiento. A principios del siglo XX la fachada se transforma radicalmente, con la aparición del vidrio plano de grandes dimensiones, y se despoja de su carga historicista. La transparencia literal hace desaparecer (negar) la fachada. La fachada se construye con nuevos materiales, nuevas tecnologías, y responde a un espacio global que espera a ser colonizado por una sociedad en constante mutación; un espacio que irá siendo cada vez más complejo a lo largo del siglo pasado y que tendrá como una de sus principales consecuencias un mayor grado de abstracción en la fachada. Para desarrollar con mayor precisión las intenciones de este trabajo se analiza la acepción de fachada en la que se encuadra la línea de investigación de la tesis doctoral. Siguiendo las indicaciones del Profesor Kenneth Frampton, se ha optado por dedicar precisamente a este análisis el primer capítulo, de precedentes, con el fin de hacer una relectura de la fachada barroca en clave contemporánea. La fachada barroca se estudia como un punto de inflexión, y origen de la transformación, frente al clasicismo de siglos precedentes. Se plantea por tanto como el primero de los mecanismos proyectuales motivo de estudio. Estos mecanismos han sido sometidos a una clasificación que responde a diversos tipos de espacio arquitectónico que han provocado la transformación de la fachada, analizando cada uno de ellos con un filtro bajo el cual se ha desarrollado un estudio pormenorizado. De esta manera se examinan la transformación compositiva de la fachada por medio del espacio dinámico (capítulo 00_precedentes) en San Carlo alle Quattro Fontane de Francesco Borromini, la transformación constructiva de la fachada por medio del espacio membrana (capítulo 01) en la Villa Tugendhat de Mies van der Rohe, la transformación diagramática de la fachada por medio del espacio pliegue (capítulo 02) en la terminal portuaria de Yokohama de FOA, la transformación tecnológica de la fachada por medio del espacio estructura (capítulo 03) en la mediateca de Sendai de Toyo Ito y, finalmente, la transformación fenomenológica de la fachada por medio del espacio múltiple (capítulo 04) en el pabellón de vidrio del Museo Toledo de SANAA. La investigación se completa con el análisis de una serie de textos que acompañan a cada uno de los capítulos, generando así un cuerpo de conocimiento global junto al análisis documental y las visitas de campo de cada uno de los casos de estudio considerados. ABSTRACT This doctoral thesis entitled “The Transformation of the Façade in Twentieth Century Architecture. The Evolution of Architectural Elements Towards a Single Space“ employs a deductive methodology incorporating both archival and field research, to examine the main design strategies that have given rise to the architectural transformation of the façade. The term façade, usually read as a synonym for architecture, has been analyzed under historiographic, sociopolitical, formal, compositive and material taxonomies. Far beyond these classifications, this study determines how architectural elements have evolved towards a single space, consequently transforming both the physical reality and the concept of façade. As Robert Venturi would say,1 to design from the inside-out and from the outside-in can create valid tensions that help generate architecture, hence the importance of this study of the transformation of the façade as a faccia, a mask, disguise or representation system, to the façade as an active diaphragm, a connective space or a limit within which architectural events with new meaning take place. The term fachada (Spanish for façade), from the Latin facies and the Italian facciata, appeared as such during the sixteenth century, although as an architectural element it is a classical ingredient and a humanist concept reinvented during the Renaissance. At the beginning of the 20th century, the façade is radically transformed with the introduction of large format plate glass, stripping it of its historicist content. Literal transparency causes the façade to disappear. The façade is built with new materials, new technologies, responding to a global space to be occupied by an everchanging society. It is a space that becomes increasingly more complex throughout the last century and which will have, as a consequence, a larger degree of abstraction in the façade. In order to more precisely focus this investigation, the meaning of the façade has been scrutinized. Following Professor Kenneth Frampton’s advice, the first chapter -Precedents- is precisely dedicated to this analysis, in order to understand the baroque façade read in a contemporary manner. The baroque façade has been studied as a turning point, the origin of the transformation of the façade, as compared to the classicism of previous centuries. For this reason it is considered the first design strategy to be studied. These strategeies have been sorted into a classification of architectural spaces that have caused the transformation of the façade, all of which having been analyzed using a methodology allowing for detailed study. Thus, this investigation examines the compositional transformation of the façade by means of a dynamic space (chapter 00: Precedents) in San Carlo alle Quattro Fontane by Francesco Borromini, the constructive transformation of the façade by means of a membrane space (chapter 01) in the Tugendhat Villa by Mies van der Rohe, the diagrammatic transformation of the façade by means of a folded space (chapter 02) in the Yokohama International Port Terminal by FOA, the technological transformation of the façade by means of a structure space (chapter 03) in the Sendai Mediathèque by Toyo Ito, and finally, the technological transformation of the façade by means of multiple space (chapter 04) in the Glass Pavilion of the Toledo Museum of Art by SANAA. The research is supplemented by the analysis of a series of texts presented alongside each chapter; creating a global body of knowledge together alongside the documentary analysis and on site analysis of each of the case studies considered.
Resumo:
Recombinant type 3 ryanodine receptor (RyR3) has been purified in quantities sufficient for structural characterization by cryoelectron microscopy and three-dimensional (3D) reconstruction. Two cDNAs were prepared and expressed in HEK293 cells, one encoding the wild-type RyR3 and the other encoding RyR3 containing glutathione S-transferase (GST) fused to its amino terminus (GST-RyR3). RyR3 was purified from detergent-solubilized transfected cells by affinity chromatography using 12.6-kDa FK506-binding protein in the form of a GST fusion as the affinity ligand. Purification of GST-RyR3 was achieved by affinity chromatography by using glutathione-Sepharose. Purified recombinant RyR3 and GST-RyR3 proteins exhibited high-affinity [3H]ryanodine binding that was sensitive to activation by Ca2+ and caffeine and to inhibition by Mg2+. 3D reconstructions of both recombinant RyR3 and GST-RyR3 appeared very similar to that of the native RyR3 purified from bovine diaphragm. Comparison of the 3D reconstructions of RyR3 and GST-RyR3 revealed that the GST domains and, hence, the amino termini of the RyR3 subunits are located in the “clamp” structures that form the corners of the square-shaped cytoplasmic region of homotetrameric RyR3. This study describes the 3D reconstruction of a recombinant ryanodine receptor and it demonstrates the potential of this technology for characterizing functional and structural perturbations introduced by site-directed mutagenesis.
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The Rab3 small G protein family consists of four members, Rab3A, -3B, -3C, and -3D. Of these members, Rab3A regulates Ca2+-dependent neurotransmitter release. These small G proteins are activated by Rab3 GDP/GTP exchange protein (Rab3 GEP). To determine the function of Rab3 GEP during neurotransmitter release, we have knocked out Rab3 GEP in mice. Rab3 GEP−/− mice developed normally but died immediately after birth. Embryos at E18.5 showed no evoked action potentials of the diaphragm and gastrocnemius muscles in response to electrical stimulation of the phrenic and sciatic nerves, respectively. In contrast, axonal conduction of the spinal cord and the phrenic nerve was not impaired. Total numbers of synaptic vesicles, especially those docked at the presynaptic plasma membrane, were reduced at the neuromuscular junction ∼10-fold compared with controls, whereas postsynaptic structures and functions appeared normal. Thus, Rab3 GEP is essential for neurotransmitter release and probably for formation and trafficking of the synaptic vesicles.
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The energetics of a fusion pathway is considered, starting from the contact site where two apposed membranes each locally protrude (as “nipples”) toward each other. The equilibrium distance between the tips of the two nipples is determined by a balance of physical forces: repulsion caused by hydration and attraction generated by fusion proteins. The energy to create the initial stalk, caused by bending of cis monolayer leaflets, is much less when the stalk forms between nipples rather than parallel flat membranes. The stalk cannot, however, expand by bending deformations alone, because this would necessitate the creation of a hydrophobic void of prohibitively high energy. But small movements of the lipids out of the plane of their monolayers allow transformation of the stalk into a modified stalk. This intermediate, not previously considered, is a low-energy structure that can reconfigure into a fusion pore via an additional intermediate, the prepore. The lipids of this latter structure are oriented as in a fusion pore, but the bilayer is locally compressed. All membrane rearrangements occur in a discrete local region without creation of an extended hemifusion diaphragm. Importantly, all steps of the proposed pathway are energetically feasible.
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Esta dissertação apresenta o desenvolvimento de uma plataforma inercial autônoma com três graus de liberdade para aplicação em estabilização de sensores - por exemplo, gravimétricos estacionários e embarcados - podendo ser utilizada também para estabilização de câmeras. O sistema é formado pela Unidade de Medida Inercial, IMU, desenvolvida utilizando um sensor micro eletromecânico, MEMS - que possui acelerômetro, giroscópio e magnetômetros nos três eixos de orientação - e um microcontrolador para aquisição, processamento e envio dos dados ao sistema de controle e aquisição de dados. Para controle dos ângulos de inclinação e orientação da plataforma, foi implementado um controlador PID digital utilizando microcontrolador. Este recebe os dados da IMU e fornece os sinais de controle utilizando as saídas PWM que acionam os motores, os quais controlam a posição da plataforma. Para monitoramento da plataforma foi desenvolvido um programa para aquisição de dados em tempo real em ambiente Matlab, por meio do qual se pode visualizar e gravar os sinais da IMU, os ângulos de inclinação e a velocidade angular. Testou-se um sistema de transmissão de dados por rádio frequência entre a IMU e o sistema de aquisição de dados e controle para avaliar a possibilidade da não utilização de slip rings ou fios entre o eixo de rotação e os quadros da plataforma. Entretanto, verificou-se a inviabilidade da transmissão em razão da baixa velocidade de transmissão e dos ruídos captados pelo receptor de rádio frequência durante osmovimentos da plataforma. Sendo assim, dois pares de fios trançados foram utilizados fios para conectar o sensor inercial ao sistema de aquisição e processamento.
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En este trabajo se describe el proceso llevado a cabo para analizar numéricamente mediante el método de los elementos finitos (MEF) el comportamiento vibratorio del conjunto móvil de un altavoz dinámico de bobina con doble suspensión inferior y en ausencia de la superior. El estudio se centra en el rango de baja frecuencia. El calibrado del modelo se realiza en base a medidas experimentales de la frecuencia de resonancia y desplazamiento del diafragma. Se hace énfasis en la importancia de los factores de participación asociados a la fuerza de excitación y en los cambios que se producen en estos al introducir fuerzas no equilibradas. Así mismo, el análisis proporciona datos para decidir sobre la distancia entre suspensiones, su número óptimo de pliegues y la ubicación de las trencillas, siendo estos parámetros de gran interés en el diseño de este tipo de altavoces.
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A stable isotope record from the eastern Weddell Sea from 69°S is presented. For the first time, a 250,000-yr record from the Southern Ocean can be correlated in detail to the global isotope stratigraphy. Together with magnetostratigraphic, sedimentological and micropalaeontological data, the stratigraphic control of this record can be extended back to 910,000 yrs B.P. A time scale is constructed by linear interpolation between confirmed stratigraphic data points. The benthic d18O record (Epistominella exigua) reflects global continental ice volume changes during the Brunhes and late Matuyama chrons, whereas the planktonic isotopic record (Neogloboquadrina pachyderma) may be influenced by a meltwater lid caused by the nearby Antarctic ice shelf and icebergs. The worldwide climatic improvement during deglaciations is documented in the eastern Weddell Sea by an increase in production of siliceous plankton followed, with a time lag of approximately 10,000 yrs, by planktonic foraminifera production. Peak values in the difference between planktonic and benthic d13C records, which are 0.5 per mil higher during warm climatic periods than during times with expanded continental ice sheets, also suggest increased surface productivity during interglacials in the Southern Ocean.
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Paleomagnetic studies conducted on board JOIDES Resolution during Leg 119 indicate that the cores collected at Site 744 range from Quaternary through Eocene in age. Initial studies of the sediments completed on board the ship measured the magnetization of the archive halves of the sedimentary cores, using the pass-through cryogenic magnetometer. Stratigraphic plots of the declination and inclination derived from these measurements displayed numerous long intervals with essentially constant magnetic directions. Further study of these intervals led to a discovery that the background signal had been incorrectly computed due to faulty software on the ship. Because this background signal was not recorded in the data-processing system, corrections could not be made. Therefore, subsequent shorebased studies have been made on the individual samples collected at approximately 30-cm intervals in the cores in order to verify the initial magnetostratigraphy reported in the Initial Reports volume for Leg 119 (Barron, Larsen, et al., 1989, doi:10.2973/odp.proc.ir.119.1989). Numerous reversals were identified and correlations were suggested with the seafloor magnetic anomaly sequence of Berggren et al. (1985, doi:10.1130/0016-7606(1985)96<1407:CG>2.0.CO;2) back to anomaly number 17.
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Surface currents and sediment distribution of the SE South American upper continental margin are under influence of the South American Monsoon System (SAMS) and the Southern Westerly Wind Belt (SWWB). Both climatic systems determine the meridional position of the Subtropical Shelf Front (STSF) and probably also of the Brazil-Malvinas Confluence (BMC). We reconstruct the changing impact of the SAMS and the SWWB on sediment composition at the upper Rio Grande Cone off southern Brazil during the last 14 cal kyr combining sedimentological, geochemical, micropaleontological and rock magnetic proxies of marine sediment core GeoB 6211-2. Sharp reciprocal changes in ferri- and paramagnetic mineral content and prominent grain-size shifts give strong clues to systematic source changes and transport modes of these mostly terrigenous sediments. Our interpretations support the assumption that the SAMS over SE South America was weaker than today during most of the Late Glacial and entire Early Holocene, while the SWWB was contracted to more southern latitudes, resembling modern austral summer-like conditions. In consequence, the STSF and the BMC were driven to more southern positions than today's, favoring the deposition of Fe-rich but weakly magnetic La Plata River silts at the Rio Grande Cone. During the Mid Holocene, the northern boundary of the SWWB migrated northward, while the STSF reached its northernmost position of the last 14 cal kyr and the BMC most likely arrived at its modern position. This shift enabled the transport of Antarctic diatoms and more strongly magnetic Argentinean shelf sands to the Rio Grande Cone, while sediment contributions from the La Plata River became less important. During the Late Holocene, the modern El Niño Southern Oscillation set in and the SAMS and the austral tradewinds intensified, causing a southward shift of the STSF to its modern position. This reinforced a significant deposition of La Plata River silts at the Rio Grande Cone. These higher magnetic silts with intermediate Fe contents mirror the modern more humid terrestrial climatic conditions over SE South America.