Examinando por Materia "Acoustics"
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- PublicaciónAcceso abiertoAnálisis de factores de confort acústico y su relación con variables de ventilación de entrada en aulas de instituciones educativas ubicadas en ciudades de clima tropical (caso de estudio Medellín)(2018) Rendón Giraldo, Jeiser; Tafur Jiménez, Luis Alberto; Morales Maya, CatalinaThe following research framed within the research project "Identification of factors of environmental performance (acoustic, thermal and visual) determinants of the mental health of teachers and students of public schools in Bogotá, Medellín and Cali, evaluates some variables of the current conditions of acoustic comfort and ventilation that public educational institutions of Medellin and the impact of ventilation on acoustic comfort. The analysis starts from the question that arises, before the educational buildings developed after the year 2000, year in which the Colombian Technical Norm NTC4595 "Approach and design of school facilities and environments" was published. It becomes relevant in this investigation to know the conditions of comfort in the educational classrooms and to evaluate the adoption of its content by the construction sector. The methodology used for this research, takes as sample 3 educational institutions, in which 7 classrooms were measured, from each classroom the building, geographical, acoustic information and the typology of the openings used for natural ventilation were raised. In addition, other quantitative variables that could help to clarify the results as they were (internal temperature, internal air velocity at the entrance of the opening, relative humidity and atmospheric pressure). In the analysis of results, it was found that a large percentage of the classrooms comply with the ventilation parameters established by NTC4595 (effective area of ventilation and height); but, they overcome the acoustic variables (background noise, reverberation time and transmission loss).
- PublicaciónAcceso abiertoAnálisis de resonadores de Helmholtz a partir de la implementación del método de elementos finitos(2019) Duque Salcedo, Andrés Felipe; Franco Bedoya, Ramiro EstebanThe project consists of studying the acoustic and physical behavior of the Helmholtz resonators, which according to their dimensions can have different resonance frequencies. The analysis will be done by means of the finite element method (FEM), whose mathematical calculation model provides greater proximity to a real system; This is achieved through matrix arrays. The studies carried out to date on the finite element method focused on acoustics have been carried out for the modal analysis of enclosures, analysis of acoustic silencers for industrial machinery and is often used in the creation of electroacoustic prototypes, such as loudspeakers and microphones. In addition, this method has the advantage of coupling several physical phenomena, for example obtaining data about the temperature and at the same time the acoustics of some model, that is why this method is implemented for the characterization of acoustic materials such as the Helmholtz resonators. Initially, the equation of an acoustic wave is described, which makes it easier to show what is the behavior of the sound in a general way to later center said equation in a particular case, the Helmholtz resonators, which are described from the Helmholtz equation. After having raised the mathematical and physical problem, we proceed to solve it by the aforementioned method. The main advantages of using FEM to analyze materials such as Helmholtz resonators are in the optimization of this process in terms of time and money. In addition, it is vital to know that this method is recurrent as long as you have a processing capacity in the machines too high. The evaluation of the finite element method is performed in the simulation software comsol multiphysics using two different 3D models of Helmholtz resonators, each with different physical characteristics, the simple cavity resonator and the cavity resonator. simple based on slats. Each of the models will have four designs, two for low frequency and two for low medium frequency, having a total of eight simulations
- PublicaciónAcceso abiertoEstudio de la atenuación lograda por un sistema de control activo de ruido implementado en audífonos supra aurales cerrados(2017) Pérez Arango, Alejandro; Natera Urueta, Erick Javier; García Mayén, HéctorOn this work, the operation of the adaptive LMS algorithm and its implementation in a system of Active Noise Cancellation (CAR) was studied. It’s use as method of characterizing systems with respect to specific stimuli, such as pure tones, pink noise and ambient noise city, these was reproduced in a controlled environment is also discussed. CAR system could not be implemented in real time, due to limitations of Matlab, which was the language chosen for programming the adaptive filter. The results of the measurements revealed weaknesses in the method used for collecting data, which did not reach the expected performance, trying to simulate the actions of the algorithm in real time, with experiments performed by separate play-capture, processing and playback stages -data collection.
- PublicaciónAcceso abiertoPropuesta metodológica para la valoración cuantitativa y cualitativa del confort acústico en aulas de clases(2016-06-13) Varela Joven, Andrés Felipe; Franco Guevara, Rodrigo AndrésThe intelligibility of speech is linked with acoustic enclosures comfort for educational purposes. That is why the RT and Noise Criteria curves are key parameters in areas devoted to teaching and / or learning. In the construction of such enclosures in Colombia is not common consideration of acoustic criteria. In this study, a quantitative and qualitative assessment of acoustic comfort for classrooms is proposed by a methodology to assess the site from its most critical point immersed evaluating noise or acoustic construction.