7 research outputs found
Robust Linear Longitudinal Feedback Control of a Flapping Wing Micro Air Vehicle
This paper falls under the idea of introducing biomimetic miniature air vehicles in ambient assisted living and home health applications. The concepts of active disturbance rejection control and flatness based control are used in this paper for the trajectory tracking tasks in the flapping-wing miniature air vehicle (FWMAV) time-averaged model. The generalized proportional integral (GPI) observers are used to obtain accurate estimations of the flat output associated phase variables and of the time-varying disturbance signals. This information is used in the proposed feedback controller in (a) approximate, yet close, cancelations, as lumped unstructured time-varying terms, of the influence of the highly coupled nonlinearities and (b) the devising of proper linear output feedback control laws based on the approximate estimates of the string of phase variables associated with the flat outputs simultaneously provided by the disturbance observers. Numerical simulations are provided to illustrate the effectiveness of the proposed approach
HEAT TRANSFER ENHANCEMENT IN A HORIZONTAL CHANNEL BY THE ADDITION OF CURVED BAFFLES
ABSTRACT This paper presents the heat transfer and flui
Sonido, Ultrasonido y Cavitaci贸n
We present in an accessible way and avoiding the mathematical language the main characteristics of the phenomenon of
cavitation. We intend to provide the concepts to understand the conditions of generation, development and implosion of
the bubbles created by the passage of a sound wave of a certain frequency and intensity in an aqueous medium. The effect
of cavitation on the surface structure of the leaves of aquatic lirium plants exposed to sonic or ultrasonic irradiation is
discussed.Presentamos en una forma accesible y evitando el lenguaje matem谩tico las principales caracter铆sticas del fen贸meno de la
cavitaci贸n. Pretendemos proporcionar los conceptos para entender las condiciones de generaci贸n, desarrollo e implosi贸n
de las burbujas creadas al paso de una onda sonora de determinada frecuencia e intensidad en un medio acuoso. Se
comenta sobre el efecto de la cavitaci贸n en la estructura superficial de las hojas de las plantas de lirio acu谩tico expuestas
a irradiaci贸n s贸nica o ultras贸nica
Application of photoacoustic spectroscopy in the study of optical absorption in n-type porous silicon
The application of the photoacoustic spectroscopy technique in the study of the optical absorption spectrum in samples of porous silicon n-type is reported. A spectral range of 250 to 800 nm and modulation frequencies of 200 Hz were used. The differential optical absorption spectrum obtained shows two significant absorption bands, one in the visible
region and the other in the UV region, which is consistent with the quantum confinement model. These optical absorption remarkable properties give porous silicon a particular importance for its application as a photothermal material.Se reporta la aplicaci贸n de la t茅cnica de espectroscop铆a fotoac煤stica en el estudio del espectro de absorci贸n 贸ptico en muestras de silicio poroso tipo n. Se utiliz贸 un rango espectral de 250 a 800 nm y frecuencias de modulaci贸n del haz monocrom谩tico de 200 Hz. El espectro de absorci贸n 贸ptico diferencial obtenido muestra dos importantes bandas de
absorci贸n, una en la regi贸n visible y la otra en la regi贸n UV, que es consistente con el modelo de confinamiento cu谩ntico. Estas notables propiedades de absorci贸n 贸ptica dan al silicio poroso una importancia particular para su aplicaci贸n como material fotot茅rmico