Cámaras anecoicas acústicas de bajo costo y fácil implementación

In this paper, the design, construction and verification of a low-cost and easy-to-install anechoic chamber are described. The chamber is constructed with affordable, local materials. The quality, according to the deviation from the inverse square law, complies with ISO 3745. The working dimensions of the chamber are 1.94 m long x 1.91 m wide x 1.84 m high. The nominal cutoff frequency is 400 Hz. The cost per square meter of the effective finished volume is 200 USD. With this design, small- and medium-sized enterprises are able to build anechoic chambers with a small investment, adding value to their products through characterization and subsequent mitigation, conditioning or amplification, as necessary, of emitted sound or noise. This study also contributes to the development and appropriation of knowledge in acoustics, a branch of physics of emerging importance in developing countries.En este trabajo se presenta el diseño, construcción y evaluación de una cámara anecoica de bajo costo usando materiales provistos por el mercado local; tales como: espuma de poliuretano, tubos de acero, fibra de vidrio, placas de fibrocemento, placas de madera aglomerada, etc. La cámara posee dimensiones de trabajo de 1,94 m de largo x 1,91 m de ancho x 1,84 m de alto y frecuencia de corte nominal de 400 Hz, a partir de la cual la cámara recrea condiciones de espacio al aire libre en cuanto a ondas sonoras se refiere. Pudo constatarse que la cámara cumple con la desviación máxima permitida de la ley del inverso cuadrado según la norma ISO 3745. El desarrollo de este tipo de proyectos es de vital importancia para la evolución tecnológica de países emergentes, ya que estimula la actividad de los investigadores y da posibilidades a la industria local para el desarrollo de procesos y productos en temas relacionados con la Acústica, temática poco desarrollada en países en vía de desarrollo

Cámaras anecoicas acústicas de bajo costo y fácil implementación

In this paper, the design, construction and verification of a low-cost and easy-to-install anechoic chamber are described. The chamber is constructed with affordable, local materials. The quality, according to the deviation from the inverse square law, complies with ISO 3745. The working dimensions of the chamber are 1.94 m long x 1.91 m wide x 1.84 m high. The nominal cutoff frequency is 400 Hz. The cost per square meter of the effective finished volume is 200 USD. With this design, small- and medium-sized enterprises are able to build anechoic chambers with a small investment, adding value to their products through characterization and subsequent mitigation, conditioning or amplification, as necessary, of emitted sound or noise. This study also contributes to the development and appropriation of knowledge in acoustics, a branch of physics of emerging importance in developing countries.En este trabajo se presenta el diseño, construcción y evaluación de una cámara anecoica de bajo costo usando materiales provistos por el mercado local; tales como: espuma de poliuretano, tubos de acero, fibra de vidrio, placas de fibrocemento, placas de madera aglomerada, etc. La cámara posee dimensiones de trabajo de 1,94 m de largo x 1,91 m de ancho x 1,84 m de alto y frecuencia de corte nominal de 400 Hz, a partir de la cual la cámara recrea condiciones de espacio al aire libre en cuanto a ondas sonoras se refiere. Pudo constatarse que la cámara cumple con la desviación máxima permitida de la ley del inverso cuadrado según la norma ISO 3745. El desarrollo de este tipo de proyectos es de vital importancia para la evolución tecnológica de países emergentes, ya que estimula la actividad de los investigadores y da posibilidades a la industria local para el desarrollo de procesos y productos en temas relacionados con la Acústica, temática poco desarrollada en países en vía de desarrollo

Low-cost and easily implemented anechoic acoustic chambers.

In this paper, the design, construction and verification of a low-cost and easy-to-install anechoic chamber are described. The chamber is constructed with affordable, local materials. The quality, according to the deviation from the inverse square law, complies with ISO 3745. The working dimensions of the chamber are 1.94 m long x 1.91 m wide x 1.84 m high. The nominal cutoff frequency is 400 Hz. The cost per square meter of the effective finished volume is 200 USD. With this design, small- and medium-sized enterprises are able to build anechoic chambers with a small investment, adding value to their products through characterization and subsequent mitigation, conditioning or amplification, as necessary, of emitted sound or noise. This study also contributes to the development and appropriation of knowledge in acoustics, a branch of physics of emerging importance in developing countries.En este trabajo se presenta el diseño, construcción y evaluación de una cámara anecoica de bajo costo usando materiales provistos por el mercado local; tales como: espuma de poliuretano, tubos de acero, fibra de vidrio, placas de fibrocemento, placas de madera aglomerada, etc. La cámara posee dimensiones de trabajo de 1,94 m de largo x 1,91 m de ancho x 1,84 m de alto y frecuencia de corte nominal de 400 Hz, a partir de la cual la cámara recrea condiciones de espacio al aire libre en cuanto a ondas sonoras se refiere. Pudo constatarse que la cámara cumple con la desviación máxima permitida de la ley del inverso cuadrado según la norma ISO 3745. El desarrollo de este tipo de proyectos es de vital importancia para la evolución tecnológica de países emergentes, ya que estimula la actividad de los investigadores y da posibilidades a la industria local para el desarrollo de procesos y productos en temas relacionados con la Acústica, temática poco desarrollada en países en vía de desarrollo

Characterization of phased array-steered acoustic vortex beams

Acoustic vortex (AV) beams generation is a subject of current interest. Even though different applications have been proposed using AV, their potential of use is still to be explored. Recent research works on particle manipulation use phased array systems for AV generation because it allows a flexible beam configuration, i.e., the beam can be easily focalized and modified in its shape. However, little attention has been paid to the fact that the AV can also be electronically steered. In view of this, this work presents an study of the steering capability of an AV. In particular, we analyze the effect of the applied delay law on the structure of AV beams steered at different angles using an array transducer of 32 equidistant elements, deployed on a triangular lattice, operating at 40 kHz. Special attention is paid to the appearance of grating vortices and their characteristics. The effect of the individual element directivity on the resultant beam is also studied. Experimental measurements were carried out in order to validate numerical estimations. Obtained results paves the way for the use of electronically steered vortices in different applications. Also, the potential of use of acoustic grating vortices is discusse

Ultrasonic determination of the elastic constants of epoxy-natural fiber composites

This paper shows the applications ultrasonic through–transmission technique to determine the elastic constants of two polymer-natural fiber composite materials with potential industrial application and economic and environmental advantages. The transversely isotropic coconut-epoxy and fique-epoxy samples were analyzed using an experimental setup which allows the sample to be rotated with respect to transducers faces and measures the time-of-flight at different angles of incidence. Then, the elastic properties of the material were obtained by fitting the experimental data to the Christoffel equation. Results show a good agreement between the measured elastic constants and the values predicted by an analytical model. The velocities as a function of the incidence angle are reported and the effect of the natural fiber on the stiffness of the composite is discusse