Nonlinear viscous damping and tuned mass damper design for occupant comfort in flexible tall buildings subjected to wind loading

During wind events, tall buildings may exhibit floor accelerations levels that compromise occupant comfort. The use of energy dissipating devices to reduce peak floor accelerations is a sound strategy to improve building performance. The estimation of mean peak floor accelerations of a steel-frame building subjected to random wind forces and the design procedure of supplemental nonlinear viscous dampers to improve occupant comfort in one-year recurrence wind events are described in this paper. A stochastic wind load model is developed to estimate acceleration performance; drag, lift and torsional moments at each story are defined as random stationary processes by the definition of their cross-spectral density matrix. Wind tunnel results and computational fluid dynamic analyses are used to fine-tune the stochastic load models. Reduced-order structural models of the tower are developed to estimate the frequency response function from floor loadings to floor accelerations at corners points of the buildings. Statistical linearization is used to estimate the performance of the buildings with non-linear viscous dampers installed in different configurations. Floor acceleration reductions achieved with supplemental viscous dampers and a tuned mass damper are evaluated to comply with occupant performance standards.Publicado en: Mecánica Computacional vol. XXXV, no. 12Facultad de Ingenierí

Nonlinear viscous damping and tuned mass damper design for occupant comfort in flexible tall buildings subjected to wind loading

During wind events, tall buildings may exhibit floor accelerations levels that compromise occupant comfort. The use of energy dissipating devices to reduce peak floor accelerations is a sound strategy to improve building performance. The estimation of mean peak floor accelerations of a steel-frame building subjected to random wind forces and the design procedure of supplemental nonlinear viscous dampers to improve occupant comfort in one-year recurrence wind events are described in this paper. A stochastic wind load model is developed to estimate acceleration performance; drag, lift and torsional moments at each story are defined as random stationary processes by the definition of their cross-spectral density matrix. Wind tunnel results and computational fluid dynamic analyses are used to fine-tune the stochastic load models. Reduced-order structural models of the tower are developed to estimate the frequency response function from floor loadings to floor accelerations at corners points of the buildings. Statistical linearization is used to estimate the performance of the buildings with non-linear viscous dampers installed in different configurations. Floor acceleration reductions achieved with supplemental viscous dampers and a tuned mass damper are evaluated to comply with occupant performance standards.Publicado en: Mecánica Computacional vol. XXXV, no. 12Facultad de Ingenierí

Nonlinear viscous damping and tuned mass damper design for occupant comfort in flexible tall buildings subjected to wind loading

During wind events, tall buildings may exhibit floor accelerations levels that compromise occupant comfort. The use of energy dissipating devices to reduce peak floor accelerations is a sound strategy to improve building performance. The estimation of mean peak floor accelerations of a steel-frame building subjected to random wind forces and the design procedure of supplemental nonlinear viscous dampers to improve occupant comfort in one-year recurrence wind events are described in this paper. A stochastic wind load model is developed to estimate acceleration performance; drag, lift and torsional moments at each story are defined as random stationary processes by the definition of their cross-spectral density matrix. Wind tunnel results and computational fluid dynamic analyses are used to fine-tune the stochastic load models. Reduced-order structural models of the tower are developed to estimate the frequency response function from floor loadings to floor accelerations at corners points of the buildings. Statistical linearization is used to estimate the performance of the buildings with non-linear viscous dampers installed in different configurations. Floor acceleration reductions achieved with supplemental viscous dampers and a tuned mass damper are evaluated to comply with occupant performance standards.Publicado en: Mecánica Computacional vol. XXXV, no. 12Facultad de Ingenierí

Juan Rodríguez Mafra y los marinos onubenses en la primera vuelta al mundo

págs.: 75-99Capítulo incluido en el libro: Actas de las Jornadas de Historia sobre el Descubrimiento de América. Tomo II: Jornadas IV, V y VI, 2008, 2009, y 2010. Eduardo García Cruzado (Coordinación). Sevilla: Universidad Internacional de Andalucía, 2011. ISBN 978-84-7993-211-4. Enlace: http://hdl.handle.net/10334/336

Soluciones alternativas para disminuir el spread bancario. Análisis económico.

Los últimos informes de competitividad global confirman que en Chile el spread de las tasas de interés bancarias es bastante alto en relación a sus vecinos y los demás países relativamente desarrollados. Como respuesta, gran parte de los medios y la opinión popular culpan de ello a un mercado bancario chileno poco competitivo, exigiendo reformas a un sistema estratégico, en extremo sensible y regulado. El presente estudio tiene por objeto demostrar cuán razonable es cuestionar aquella exigencia –dada las características del mercado, la función social y económica que cumple, y el peligro de intervenirlo forzosamente a fin de hacerlo más competitivo-  y considerar que existen soluciones más eficientes, más pacíficas, y menos riesgosas. Se propone el concepto de costo de no pago como variable determinante en la estructura de costos del interés bancario, y por consiguiente, su disminución como una alternativa viable de regulación

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Población de una base de datos jurisprudencial a base del libro registro de sentencias de la Corte Suprema, 1999

Memoria (licenciado en ciencias jurídicas y sociales)No autorizada por el autor para ser publicada a texto completoSentencias emanadas de la Corte Suprema, publicadas en el Libro Registro de Sentencias de la Corte Suprema, agosto, septiembre y octubre, año 1999. Total de documentos analizados: 301

Un Análisis Econométrico del Consumo Mundial de Celulosa

En este trabajo se especifica y estima un modelo econométrico para el consumo de celulosa a nivel mundial y desagregado según los principales países consumidores. El modelo utilizado corresponde a uno de demanda derivada para una firma productora de papel representativa que demandará celulosa como un insumo más para su producción. Esta demanda es posteriormente agregada a nivel de país para la estimación econométrica. Las elasticidades del consumo mundial son obtenidas mediante simulaciones del modelo agregado. Luego se estudia la capacidad del modelo para replicar los datos históricos, su respuesta ante shocks transitorios sobre ciertas variables relevantes y su comportamiento fuera del período de estimación. Los resultados obtenidos son acordes con la evidencia empírica existente. La elasticidad precio del consumo a nivel mundial tiene un valor -0,20 en el corto plazo (CP) y -0,24 en el largo plazo (LP). El ingreso de los países resultó ser una de las variables que tiene gran influencia en el consumo de celulosa; la elasticidad ingreso encontrada fue 1,02 y 1,12 para el CP y LP respectivamente. En este estudio se incorporó también el efecto del precio del papel reciclado, obteniéndose una elasticidad precio cruzada de 0,22 en el CP y de 0,24 en el LP, lo que pone de manifiesto la sustitución entre estos productos. Para el precio de la energía se obtuvo una elasticidad de -0,01 tanto en el CP como en el LP. El hecho que no se registraran diferencias significativas entre las elasticidades de corto y largo plazo indicaría según el modelo planteado, que el consumo de celulosa no sufre mayores ajustes entre lo que es consumo corriente y el de largo plazo o de equilibrio. Los resultados indican además que si bien es innegable la importancia creciente en el consumo mundial de celulosa que han tenido países en vías de desarrollo como China, actualmente son los países industrializados los que tienen una mayor incidencia en el consumo mundial; luego, escenarios futuros para el consumo de este producto, al menos en el corto plazo, debiesen estar ligados con el comportamiento de estos países. El estudio muestra además que el modelo agregado es capaz de replicar satisfactoriamente los datos históricos dentro de la muestra, así como también los datos fuera de la muestra. Finalmente una proyección a mediando plazo para el período 2003-2008 predice que el consumo de este producto debiese crecer a una tasa promedio anual del 2,3%, cifra acorde con las proyecciones que maneja la industria.

The Niña, The Pinta and The Santa María

Peer reviewe

Determination of forming limits of sheet metals by electronic speckle pattern interferometry

International audienc