Examinando por Autor "Molina Jaramillo, Alejandro"

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  • Publicación
    Acceso abierto
    Análisis de la incertidumbre asociada al georreferenciamiento de mediciones de ruido ambiental en la calibración de mapas de ruido
    (2019) Puerta Pareja, Juan Ricardo; Cuervo Ospina, Guillermo Andrés; Molina Jaramillo, Alejandro
    This research proposes a methodology to quantify the uncertainty effect associated with the georeferencing process in noise maps calibration, based on the calculation of the expanded uncertainty proposed by the P hD.M iguelAusejoP rieto. Field measurements were made with two simultaneous sound level meters, one of them varied it’s location taking into account the maximum tolerance that three different GPS devices have; the other level meter remained fixed at one point in order to have a reference to make a comparison between the captured simultaneously levels by the two sound level meters. The measurements were carried out in three different scenarios, in two configurations, in the peak and valley schedules and considering that the main source of noise was road traffic. In addition, this procedure was recreated by simulation methods using the German model RLS-90. With the levels obtained the calculation of the expanded uncertainty was made, taking into account a coverage factor K = 2, which guarantees a confidence level of 95,45%. On the one hand the ± 3 dB criterion was evaluated, for the uncertainty levels obtained by the fixed sound level meter and the other hand, for the uncertainty levels found in the combination of the fixed and mobile sound level meter, including the biggest desviations in each one of them. Both in the results of the measurement in the simulation process there was not enough evidence to state that the accuracy of a GPS affects the calibration of a noise map, this was verified using the Wilcoxon’s rank test, which evaluates if the difference between two random samples differ significantly from zero
  • Publicación
    Acceso abierto
    Diseño de una metodología alternativa que permita la caracterización de la radiación de una fuente electroacústica mediante el uso de una sonda P-U.
    (2017) Luján López, Luis Fernando; Estrada Duarte, Sergio Andrés; Molina Jaramillo, Alejandro
    Through the study of the standards for the determination of the sound intensity and the traditional measurement protocols to obtain the descriptors of radiation of electroacoustic sources an in situ methodology was designed that allows to estimate, for a Genelec 1032A loudspeaker, the vectorial field of intensity normal to measuring surface using the PU sensor and the Microflown´s Sound Power software. We sought to estimate a scalar and a vector unit, pressure and particle velocity respectively. Through these it was possible to calculate the measured intensity of the under study loudspeaker and thus obtain a representation of the vector field of intensity, a three-dimensional graph of its radiation. It is also understood that the measurements for pressure estimation must be performed under free field conditions, because this variable is affected by the reflections of the measurement environment due it is not of the vectorial type, for which it is not necessary to consider these contributions. An algorithm was developed for the processing of the data, so that the results could be projected on each one of the measurement positions by frequencies of third of octave. The reproducibility of the method was also evaluated by measurements in different acoustic environments. In a site with acoustic treatment the measurement distance is greater than in an enclosure without treatment due to the variation of the near field. In spite of this, it was possible to obtain satisfactory results in both places keeping the same configuration in the measurement elements.
  • Publicación
    Acceso abierto
    Evaluación de los métodos de estimación de potencia sonora basados en presión y en el uso de la sonda p-u microflown para la caracterización acústica de los electrodomésticos de la línea Assento de Haceb
    (2014) Molina Jaramillo, Alejandro; Tafur Jiménez, Luis Alberto; García Mayén, Héctor
    Mediante la evaluación de técnicas de medición de potencia acústica estandarizadas (ISO 3744) y de la tecnología Microflown se cuantifica el nivel de ruido e identifican los principales mecanismos generadores de sonido en la serie de electrodomésticos ASSENTO de la compañía HACEB. Un análisis de los resultados obtenidos tras la medición de las variables acústicas y la localización de las fuentes de ruido en los refrigeradores de la línea descrita, posibilita demostrar cuál es la técnica más conveniente que debería emplear un posible dispositivo viable provisto para la caracterización acústica de los electrodomésticos HACEB en la planta de producción. El estándar internacional basado en presión ISO 3744 y el método de la tecnología Microflown, basado en la sonda tipo p-u (presión – velocidad de partícula), se aplicó a los refrigeradores en estudio para la determinación de los niveles de potencia sonora y la localización de los mecanismos generadores de sonido. Los resultados de estas mediciones y otras adicionales se comparan y discuten con el fin de esclarecer su conveniencia para la cuantificación del ruido en el entorno donde se ensamblan los electrodomésticos en cuestión.