David Duran - Academia.edu (original) (raw)

Papers by David Duran

Aprendizaje Cooperativo En Las Aulas Fundamentos Y Recursos Para Su Implantacion 2012 Isbn 978 84 206 6961 8 Pags 139 166, 2012

A synthetic Jet actuator is a device which moves a fluid in and outside a cavity, through a small... more A synthetic Jet actuator is a device which moves a fluid in and outside a cavity, through a small aperture, by the continuous oscillation of a diaphragm. This diaphragm is usually a piezoelectric disk which is excited by a sinusoidal voltage. The first approach to the problem was to validate the behavior of the piezoelectric disk through a tridimensional model, showing satisfactory results. After this validation an axisymmetric model of the complete (fluid + piezoelectric) synthetic jet actuator was implemented. This model was used to analyze the influence of the relevant dimensionless numbers in the synthetic jet formation when the disk was excited at low frequencies. Numerical results of this model show a strong dependence of the synthetic jet formation on the size of the aperture. Another relevant observation is that, for the case of synthetic jet formation, there is an interaction between the entering momentum and the diaphragm, which has not been observed in other synthetic jet models based only on Navier-Stokes solver. All these observations are of great help in synthetic jet device research and development, and encourage further multiphysics simulations and analysis of these actuators to be made.

Page 1. Computational Modeling of Synthetic Jets David C. Durán*,1, Omar D. López2 1Mechanical En... more Page 1. Computational Modeling of Synthetic Jets David C. Durán*,1, Omar D. López2 1Mechanical Engineering Department, Universidad de los Andes, Bogotá - Colombia *Corresponding author: Carrera 1ra No. 18A-12, da-duran@uniandes.edu.co ...

Journal of Research in Reading, 2015

ABSTRACT This study relates to the results obtained in the development of reading comprehension (... more ABSTRACT This study relates to the results obtained in the development of reading comprehension (RC) and self-concept as a reader in students who participated in Llegim en parella (Reading in pairs), a Catalan peer tutoring programme. The research combines a quasi-experimental design with the use of comparison groups and pre-tests/post-tests for both variables; a qualitative approach is adopted by analysing the interactions in order to detect influencing factors. Statistically significant results were obtained for all students in terms of RC but only for student tutors in relation to reading self-concept. The factors involved in the improvements identified in RC are: reading strategies, scaffolding in inferential and deep comprehension questions. Regarding self-concept, the tutor's own role, his involvement with their tutees' progress, reading aloud and the metacognitive reflection processes, are all factors that enable us to explain the improvement in the tutor's reading self-perception. The positive influence of peer tutoring on the development of reading competence through this programme is clearly evident.

Journal of Research in Reading, 2015

Remediation Journal, 1997

Joseph E. Odencrantz, Ph.D,, PE, is a regis-tered civil engineer with approximately 15 years of e... more Joseph E. Odencrantz, Ph.D,, PE, is a regis-tered civil engineer with approximately 15 years of experience in the fields of environmental engineering and water resources. He is the founder and President of TRI-S Environmenta4 Sensible Strategies and Solutions for the Envi- ...

Remediation Journal, 1997

Aprendizaje Cooperativo En Las Aulas Fundamentos Y Recursos Para Su Implantacion 2012 Isbn 978 84 206 6961 8 Pags 139 166, 2012

Journal of Research in Reading, 2015

Remediation Journal, 1997