O elemento finito T6-3i na análise de placas e dinâmica de cascas.

O método dos elementos finitos é o método numérico mais difundido na análise de estruturas. Ao longo das últimas décadas foram formulados inúmeros elementos finitos para análise de cascas e placas. As formulações de elementos finitos lidam bem com o campo de deslocamentos, mas geralmente faltam testes que possam validar os resultados obtidos para o campo das tensões. Este trabalho analisa o elemento finito T6-3i, um elemento finito triangular de seis nós proposto dentro de uma formulação geometricamente exata, em relação aos seus resultados de tensões, comparando-os com as teorias analíticas de placas, resultados de tabelas para o cálculo de momentos em placas retangulares e do ANSYSr, um software comercial para análise estrutural, mostrando que o T6-3i pode apresentar resultados insatisfatórios. Na segunda parte deste trabalho, as potencialidades do T6-3i são expandidas, sendo proposta uma formulação dinâmica para análise não linear de cascas. Utiliza-se um modelo Lagrangiano atualizado e a forma fraca é obtida do Teorema dos Trabalhos Virtuais. São feitas simulações numéricas da deformação de domos finos que apresentam vários snap-throughs e snap-backs, incluindo domos com vincos curvos, mostrando a robustez, simplicidade e versatilidade do elemento na sua formulação e na geração das malhas não estruturadas necessárias para as simulações.

Análisis del movimiento en secuencias de imágenes

Este trabajo presenta el desarrollo de una aplicación destinada al análisis de secuencias de imágenes para la detección de movimiento en la escena. Se trata de un campo importante de la Visión Artificial, con múltiples aplicaciones entre las que se encuentra la videovigilancia con fines de seguridad, el control de tráfico, el movimiento de personas o el seguimiento y localización de objetos entre otras muchas. Para ello se utilizan métodos de análisis como son el de Lucas-Kanade y Gauss-Seidel, que obtienen el denominado flujo óptico. Este describe el movimiento que ha tenido lugar entre las imágenes y su fundamento estriba en la determinación de las variables espaciales y temporales en las imágenes, siendo precisamente la variable temporal la que introduce el concepto fundamental para el análisis del movimiento a partir de las imágenes captadas en diferentes instantes de tiempo dentro de la secuencia analizada. Para el desarrollo de la aplicación se han utilizado técnicas propias del tratamiento de la Visión Artificial, así como la metodología proporcionada por la Ingeniería del Software. Así, se ha realizado una especificación de requisitos, se ha elaborado y seguido un plan de proyecto y se ha realizado un análisis de alto nivel, que se materializa en el correspondiente diseño e implementación, junto con las pruebas de verificación y validación, obviamente adaptados en todos los casos a las dimensiones del proyecto, pero que establecen claramente los planteamientos básicos para el desarrollo de una aplicación a nivel empresarial. La aplicación planteada se enmarca perfectamente dentro del paradigma, hoy en día en pleno auge, conocido como el Internet de las Cosas (IoT). El IoT permite la intercomunicación entre dispositivos remotos, de forma que mediante la correspondiente comunicación a través de conexiones a Internet es posible obtener datos remotos para su posterior análisis, bien en nodos locales o en la nube, como concepto íntimamente relacionado con el IoT. Este es el caso de la aplicación que se presenta, de suerte que los métodos de procesamiento de las imágenes pueden aplicarse localmente o bien transmitir las mismas para su procesamiento en nodos remotos.

On the development of advanced techniques for mixed-elastohydrodynamic lubrification modelling of journal and sliding bearing systems.

The present thesis is focused on the development of a thorough mathematical modelling and computational solution framework aimed at the numerical simulation of journal and sliding bearing systems operating under a wide range of lubrication regimes (mixed, elastohydrodynamic and full film lubrication regimes) and working conditions (static, quasi-static and transient conditions). The fluid flow effects have been considered in terms of the Isothermal Generalized Equation of the Mechanics of the Viscous Thin Films (Reynolds equation), along with the massconserving p-Ø Elrod-Adams cavitation model that accordingly ensures the so-called JFO complementary boundary conditions for fluid film rupture. The variation of the lubricant rheological properties due to the viscous-pressure (Barus and Roelands equations), viscous-shear-thinning (Eyring and Carreau-Yasuda equations) and density-pressure (Dowson-Higginson equation) relationships have also been taken into account in the overall modelling. Generic models have been derived for the aforementioned bearing components in order to enable their applications in general multibody dynamic systems (MDS), and by including the effects of angular misalignments, superficial geometric defects (form/waviness deviations, EHL deformations, etc.) and axial motion. The bearing exibility (conformal EHL) has been incorporated by means of FEM model reduction (or condensation) techniques. The macroscopic in fluence of the mixedlubrication phenomena have been included into the modelling by the stochastic Patir and Cheng average ow model and the Greenwood-Williamson/Greenwood-Tripp formulations for rough contacts. Furthermore, a deterministic mixed-lubrication model with inter-asperity cavitation has also been proposed for full-scale simulations in the microscopic (roughness) level. According to the extensive mathematical modelling background established, three significant contributions have been accomplished. Firstly, a general numerical solution for the Reynolds lubrication equation with the mass-conserving p - Ø cavitation model has been developed based on the hybridtype Element-Based Finite Volume Method (EbFVM). This new solution scheme allows solving lubrication problems with complex geometries to be discretized by unstructured grids. The numerical method was validated in agreement with several example cases from the literature, and further used in numerical experiments to explore its exibility in coping with irregular meshes for reducing the number of nodes required in the solution of textured sliding bearings. Secondly, novel robust partitioned techniques, namely: Fixed Point Gauss-Seidel Method (PGMF), Point Gauss-Seidel Method with Aitken Acceleration (PGMA) and Interface Quasi-Newton Method with Inverse Jacobian from Least-Squares approximation (IQN-ILS), commonly adopted for solving uid-structure interaction problems have been introduced in the context of tribological simulations, particularly for the coupled calculation of dynamic conformal EHL contacts. The performance of such partitioned methods was evaluated according to simulations of dynamically loaded connecting-rod big-end bearings of both heavy-duty and high-speed engines. Finally, the proposed deterministic mixed-lubrication modelling was applied to investigate the in fluence of the cylinder liner wear after a 100h dynamometer engine test on the hydrodynamic pressure generation and friction of Twin-Land Oil Control Rings.

Influencia de las medidas queratométricas en el cálculo de la potencia de lentes intraoculares

Índice, resumen, conclusiones y bibliografía de la memoria del Máster en Optometría Clínica y Visión, Programa formativo en Biomedicina y Tecnologías para la vida.

Simulación de procesos químicos (curso 2011-2012)

Apuntes en formato html que incluyen los siguientes temas de la parte de simulación en la asignatura «simulación y optimización de procesos químicos» TEMA 1. Introducción 1.1 Introducción. 1.2 Desarrollo histórico de la simulación de procesos. Relación entre simulación optimización y síntesis de procesos. 1.3 Tipos de simuladores: Modular secuencial. Modular simultáneo. Basada en ecuaciones. TEMA 2. Simulación Modular Secuencial 2.1 Descomposición de diagramas de flujo (flowsheeting) 2.2 Métodos basados en las matrices booleanas Localización de redes cíclicas máximas. Algoritmo de Sargent y Westerberg. Algoritmo de Tarjan. 2.3 Selección de las corrientes de corte: 2.3.1 Caso general planteamiento como un "set-covering problem" (algoritmo de Pho y Lapidus) 2.3.2 Número mínimo de corrientes de corte (algoritmo de Barkley y Motard) 2.3.3 Conjunto de corrientes de corte no redundante (Algoritmo de Upadhye y Grens) TEMA 3. Simulación Modular Simultánea 3.1 Efecto de las estrategias tipo cuasi Newton sobre la convergencia de los diagramas de flujo. TEMA 4. Simulación Basada en Ecuaciones 4.1 Introducción. Métodos de factorización de matrices dispersas. Métodos a priori y métodos locales. 4.2 Métodos locales: Criterio de Markowitz. 4.3 Métodos a priori: 4.3.1 Triangularización por bloques: a. Base de salida admisible (transversal completo). b. Aplicación de los algoritmos de Sargent y Tarjan a matrices dispersas. c. Reordenación. 4.3.2 Transformación en matriz triangular bordeada. 4.4 Fase numerica. Algoritmo RANKI 4.5 Comparación entre los diferentes sistemas de simulación. Ventajas e Inconvenientes. TEMA 5. Grados de libertad y variables de diseño de un diagrama de flujo 5.1 Teorema de Duhem y regla de las fases 5.2 Grados de libertad de un equipo 5.3 Grados de libertad de un diagrama de flujo 5.4 Elección de las variables de diseño.

Minimizing the IOL Power Error Induced by Keratometric Power

Purpose. To evaluate theoretically in normal eyes the influence on IOL power (PIOL) calculation of the use of a keratometric index (nk) and to analyze and validate preliminarily the use of an adjusted keratometric index (nkadj) in the IOL power calculation (PIOLadj). Methods. A model of variable keratometric index (nkadj) for corneal power calculation (Pc) was used for IOL power calculation (named PIOLadj). Theoretical differences ($PIOL) between the new proposed formula (PIOLadj) and which is obtained through Gaussian optics (PIOL Gauss) were determined using Gullstrand and Le Grand eye models. The proposed new formula for IOL power calculation (PIOLadj) was prevalidated clinically in 81 eyes of 81 candidates for corneal refractive surgery and compared with Haigis, HofferQ, Holladay, and SRK/T formulas. Results. A theoretical PIOL underestimation greater than 0.5 diopters was present in most of the cases when nk = 1.3375 was used. If nkadj was used for Pc calculation, a maximal calculated error in $PIOL of T0.5 diopters at corneal vertex in most cases was observed independently from the eye model, r1c, and the desired postoperative refraction. The use of nkadj in IOL power calculation (PIOLadj) could be valid with effective lens position optimization nondependent of the corneal power. Conclusions. The use of a single value of nk for Pc calculation can lead to significant errors in PIOL calculation that may explain some IOL power overestimations with conventional formulas. These inaccuracies can be minimized by using the new PIOLadj based on the algorithm of nkadj.

On the decorrelation filtering of RL05 GRACE data for global applications

In autumn 2012, the new release 05 (RL05) of monthly geopotencial spherical harmonics Stokes coefficients (SC) from GRACE (Gravity Recovery and Climate Experiment) mission was published. This release reduces the noise in high degree and order SC, but they still need to be filtered. One of the most common filtering processing is the combination of decorrelation and Gaussian filters. Both of them are parameters dependent and must be tuned by the users. Previous studies have analyzed the parameters choice for the RL05 GRACE data for oceanic applications, and for RL04 data for global application. This study updates the latter for RL05 data extending the statistics analysis. The choice of the parameters of the decorrelation filter has been optimized to: (1) balance the noise reduction and the geophysical signal attenuation produced by the filtering process; (2) minimize the differences between GRACE and model-based data; (3) maximize the ratio of variability between continents and oceans. The Gaussian filter has been optimized following the latter criteria. Besides, an anisotropic filter, the fan filter, has been analyzed as an alternative to the Gauss filter, producing better statistics.

Errors Associated to Keratoconus Grading using Systems based on Corneal Power

Purpose: To analyze and define the possible errors that may be introduced in keratoconus classification when the keratometric corneal power is used in such classification. Materials and methods: Retrospective study including a total of 44 keratoconus eyes. A comprehensive ophthalmologic examination was performed in all cases, which included a corneal analysis with the Pentacam system (Oculus). Classical keratometric corneal power (Pk), Gaussian corneal power (Pc Gauss), True Net Power (TNP) (Gaussian power neglecting the corneal thickness effect), and an adjusted keratometric corneal power (Pkadj) (keratometric power considering a variable keratometric index) were calculated. All cases included in the study were classified according to five different classification systems: Alió-Shabayek, Amsler-Krumeich, Rabinowitz-McDonnell, collaborative longitudinal evaluation of keratoconus (CLEK), and McMahon. Results: When Pk and Pkadj were compared, differences in the type of grading of keratoconus cases was found in 13.6% of eyes when the Alió-Shabayek or the Amsler-Krumeich systems were used. Likewise, grading differences were observed in 22.7% of eyes with the Rabinowitz-McDonnell and McMahon classification systems and in 31.8% of eyes with the CLEK classification system. All reclassified cases using Pkadj were done in a less severe stage, indicating that the use of Pk may lead to the classification of a cornea as keratoconus, being normal. In general, the results obtained using Pkadj, Pc Gauss or the TNP were equivalent. Differences between Pkadj and Pc Gauss were within ± 0.7D. Conclusion: The use of classical keratometric corneal power may lead to incorrect grading of the severity of keratoconus, with a trend to a more severe grading.

Berlin, Germany, 1920 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Kiessling's grosser plan von Berlin : mit Voroten und Völlständiger Stadt - u. Ringbahn. It was published by Alexius Kiessling in 1920. Scale 1:20,000. Covers a portion of Berlin, Germany. Map in German. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads and stations, drainage, selected buildings, parks, ground cover, city districts, and more. Relief shown by spot heights.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Göttingen, Germany, ca. 1740 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Goettinga, urbs munitissima et splendida electoratus Brunsvico-Luneburgici Academia Georgia Augusta inclyta, accurate aere repraesentata à Matth. Seuttero, Geogr. Caesar, Aug. Vind. It was published by M. Seutter, ca. 1740. Scale [ca. 1:3,500]. Covers Göttingen, Germany. Map in German and Latin.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 3 coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes indexes, illustrations, and view.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Hannover, Germany, ca. 1740 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Accurata et novissima repraesentatio ichnographica Hannoverae, sedis urbis et electoralis Brunsuico-Luneburgensis = Hannover, die Churfürst. Braunschweig-Lüneburg. Haupt- und Residentz-Stadt an der Leine gelegen, Aeri incidit et excudit Matthaeus Seutter, S. C. M. Geograph. It was published by M. Seutter ca. 1740. Scale [ca. 1:3,780]. Covers Hannover, Germany. Map in Latin and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 3 coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes indexes, illustrations, and text.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Kiel, Germany, ca. 1736 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Die Herzogl. Holstein-Gottorp. Residenz- See- und Handelstadt Kiel sambt dessen Hafen in einem accuraten Plan u. Prospect entworfen = Sereniss. Ducis Holsato-Gottorpiensis Sedes et celebre Emporium Kilonium una cum ejus Portu ichno- et scenographice accurate delineatum, delineante G. C. Holmer. It was published by Officina Homanniana ca. 1736. Scale [ca. 1:4,000]. Covers Kiel, Germany. Map in German and Latin.Note: Two maps appear on this sheet. The larger scale map of Kiel is the portion of the image that has been georeferenced.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 3 coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes also indexes and 2 views of Kiel.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Lübeck, Germany, ca. 1730 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Grund-Riss der Keyserlichen und des Heil. Röm. Reichs freyen stadt Lübeck, herausgegeben von Matth. Seutter, kayserl. Geogr. It was published by M. Seutter between 1730 and 1739. Covers Lübeck, Germany. Scale [ca. 1:5,600]. Map in German. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes indexes, illustrations, and a view.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Berlin, Germany, 1748 (Image 1 of 4) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Plan de la ville de Berlin : levé et dessiné par ordre et privilege privatif du Roy sous la direction du Marchall Comte de Schmettau, par Hildner approuvé par l'Academie Royale de Science â Berlin ; gravé sous la direction de G.F. Schmidt Graveur du Roy. It was published by l'Academie Royale de Science â Berlin in 1748. Scale [ca. 1:6,500]. Covers Berlin, Germany. This layer is image 1 of 4 total images of the four sheet source map, representing the northeast portion of the map. Map in French and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortification, parks, cemeteries, ground cover, and more. Relief shown by hachures. Includes also view and inset engravings: Prospect du Stadt Berlin von Süden gegen Norden -- 1. Prospect des grossen Platzes von Opera Hausse 2. der Cathol. Kirche St. Hedwig 3. und einer Seite des Marggraff Henrich. Pallais -- Prospect der Neuen Schloss u Dohm Kirche -- Prospect des Neuen Königl. Printz Heinrich. Pallais den Opern Hausse gegen über.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Berlin, Germany, 1748 (Image 2 of 4) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Plan de la ville de Berlin : levé et dessiné par ordre et privilege privatif du Roy sous la direction du Marchall Comte de Schmettau, par Hildner approuvé par l'Academie Royale de Science â Berlin ; gravé sous la direction de G.F. Schmidt Graveur du Roy. It was published by l'Academie Royale de Science â Berlin in 1748. Scale [ca. 1:6,500]. Covers Berlin, Germany. This layer is image 2 of 4 total images of the four sheet source map, representing the southeast portion of the map. Map in French and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortification, parks, cemeteries, ground cover, and more. Relief shown by hachures. Includes also view and inset engravings: Prospect du Stadt Berlin von Süden gegen Norden -- 1. Prospect des grossen Platzes von Opera Hausse 2. der Cathol. Kirche St. Hedwig 3. und einer Seite des Marggraff Henrich. Pallais -- Prospect der Neuen Schloss u Dohm Kirche -- Prospect des Neuen Königl. Printz Heinrich. Pallais den Opern Hausse gegen über.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.