Orientador: Stelamaris Rolla Bertoli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-09T02:39:04Z (GMT). No. of bitstreams: 1 Amorim_AdrianaEloaBento_M.pdf: 15352732 bytes, checksum: 327b5fe0a18f76c48649f2007c4f4dba (MD5) Previous issue date: 2007 / Resumo: Estudos sobre a acústica de salas de aula estão cada vez mais comuns no meio acadêmico e científico, devido à sua influência nas questões do ensino-aprendizagem. Os ambientes escolares exigem qualidade acústica que deve ser prevista já na concepção do projeto. A inadequação acústica de escolas e salas de aula é apontada em diversas pesquisas que utilizam variadas metodologias, geralmente através da aplicação de testes de acertos e erros de vocábulos, e também da análise de parâmetros de avaliação como medidas dos níveis de pressão sonora e do tempo de reverberação. Na rede estadual de ensino público em São Paulo, as salas de aula são projetadas a partir de diretrizes pré-estabelecidas que visam a padronização dos projetos de escolas. Portanto, este trabalho tem como objetivos identificar as formas geométricas mais comuns de salas de aula propostas para a rede pública estadual de ensino em Campinas-SP, apresentar o comportamento dos parâmetros acústicos quanto à inteligibilidade da fala e apontar as formas mais favoráveis à qualidade acústica de salas de aula. Para a definição da amostra realizou-se um levantamento cadastral das escolas e o levantamento arquitetônico das salas. Desse levantamento, identificou-se o número de configurações geométricas mais comuns de salas. Foram analisadas as salas dentro da uma mesma configuração padrão, totalizando dezessete salas de aula. Para a medição acústica foi utilizada a técnica da resposta impulsiva da sala e os parâmetros acústicos foram obtidos através do programa de avaliação acústica de salas, o DIRAC®, da empresa Brüel & Kjaer. Os parâmetros derivados da resposta impulsiva analisados neste trabalho foram: o Tempo de Reverberação (TR), o Tempo de Decaimento Inicial (EDT), a Definição (D50), o Índice de Transmissão da Fala (STI) e a Porcentagem de Perda na Articulação de Consoantes (%ALCons), em função da freqüência na faixa de bandas de 1/1 de oitava. Também foi medido e analisado o Nível de Pressão Sonora ou ruído de fundo ambiental equivalente (LAeq) interno e externo à sala, obtido com o medidor de pressão sonora. A análise complementar da forma para cada sala foi feita pela proporcionalidade das dimensões, segundo a escala do Diagrama de Bolt. As formas geométricas em planta mais comuns de salas são as quadradas (7x7m) e retangulares (6x8m). Dentro de cada configuração as salas apresentaram diferentes desempenhos acústicos. Pelo fato de existir uma grande variedade de fatores e parâmetros que interferem na acústica da sala, foi possível identificar algumas tendências de comportamento acústico por configuração geométrica / Abstract: Studies about classroom acoustics are developed each time more into the scientific and academic society, due to its influence in the teach-learning. The school¿s environments demand acoustical quality that must be foreseen already during the design planning. Some situations of acoustic not adjusted on classrooms are shown in research that using several methods, generally with application of word¿s rightness and error tests as well as of the analysis and evaluation of parameters as the sound pressure levels and reverberation time. In the State of Sao Paulo the classrooms of public education buildings are projected in accordance with same lines of direction that aim at the school design standardization. Therefore, this work has as objective to identify what geometric shapes are more common on classroom¿s design found in public schools at Campinas-SP, to present the acoustic parameters behavior how much to the speech intelligibility of classrooms and to point the shapes that are most favorable to the acoustical quality for classrooms. It was made classroom¿s cadastral survey for sample definition and after was made architectural survey hers. This procedure allows identifying the number of the rooms more common geometric configurations. The classrooms which have the same configuration standard were selected and analyzed, totalizing seventeen classrooms. The acoustical measurements were made using the impulse response technique of the room and the acoustical parameters were obtained of the room acoustics evaluation software, the DIRAC®, by Brüel & Kjaer. The parameters were derived from the impulse response were analyzed in this work: Reverberation Time (RT), Early Decay Time (EDT), Definition (D50), Speech Transmission Index (STI) and Percentage Articulation Loss of Consonants (%ALCons), for each 1/1 octave frequency band. Also it was analyzed the internal and external background noise or ambiental Equivalent Sound Pressure Level (LAeq), which were measured with sound pressure level meter. Complementary analysis of the form for each room was made by the proportionality of the dimensions, according to Bolt¿s Diagram scale. Among the more common geometric shapes in plant of rooms had found were: the square shaped (7x7m) and rectangular (6x8m). Inside each configuration of classroom had presented different acoustical performances. For the fact to exist a great variety of factors and parameters intervening on classroom acoustics, it was possible to identify some acoustical behaviors trends for geometric configuration / Mestrado / Arquitetura e Construção / Mestre em Engenharia Civil

Le couplage entre un écoulement instable et des résonances acoustiques dans des systèmes de conduites peut conduire à des phénomènes d’oscillations auto-induites. Ce type de phénomènes trouve principalement place dans des conduites latérales fermées, par exemple dans des systèmes de transport ou de compression de gaz. L’objectif de ce travail est d’étudier les oscillations auto-induites dans le cas où le fluide transporté ne se limite pas à un gaz, mais est un mélange de gaz et de liquide. Les pulsations sont mesurées dans des conduites latérales fermées, pour deux types de configurations (en tandem et en croix), avec écoulement d’un mélange variable d’air et d’eau. La position de l’injection d’eau est variable afin d’obtenir plusieurs régimes d’écoulement diphasique. Les résultats indiquent que la présence d’eau a un effet important sur les niveaux de pulsations dans les conduites. Cet effet a pu être attribué à deux mécanismes dus à la présence d’eau : les instabilités de couches de mélange sont modifiées et l’amortissement des ondes acoustiques est amplifié.Le deuxième mécanisme a été quantifié à l’aide de mesures sur un montage expérimental dédié conçu pour avoir un écoulement stratifié. On a observé que, dans tous les cas, la présence d’eau augmente l’amortissement. Cette augmentation a pu être attribuée à la réduction de la section effective de la conduite (due au remplissage partiel par l’eau) et à l’augmentation de la friction turbulente à l’interface entre les phases liquide et gazeuse. / Coupling between flow instabilities and acoustic resonances in ducts with closed side branches leads to Flow Induced Pulsations (FIPs). This is a typical phenomenon in engineering applications (gas transport systems, compressor installations, and chemical plants). The objective of this work is to extend the knowledge about FIPs when the transported medium is not uniquely gas but a combination of gas and (a small quantity of) liquid. For two configurations of double side branches (in tandem and in quasi-cross), the amplitude of pressure pulsations in the side branches was measured for different liquid injection rates. This was repeated with the liquid injection point located at different places to allow different flow regimes at the pipe connections. The results show a strong effect of the water content on the pulsations. On basis of these results and additional measurements, the following hypotheses for the effect of liquid were made: (1) interaction of the liquid with the flow instability and (2) increase of the acoustical damping in the ducts in presence of liquid.The effect of liquid on damping was measured with a dedicated test setup designed to have a stratified flow. It was found that the liquid always increases the acoustical damping, mainly due to the reduction of the effective cross section by the liquid, and because of the increased turbulent friction at the interface between gas and liquid.

Für die Optimierung akustischer Eigenschaften von Räumen ist die Verbesserung deren numerischer Simulationen von entscheidender Bedeutung. Im unteren Frequenzbereich hängt in vielen Fällen die Qualität der Lösungen stark von der Kenntnis akustischer Wandadmittanzen ab. Die vorliegende Arbeit umfasst die Entwicklung und Untersuchung verschiedener auf deterministischen Diskretisierungen des akustischen Randwertproblems basierender Formulierungen zur globalen Bestimmung frequenzabhängiger Admittanzparameter. Mit Admittanzen kann das Reflexions- und Absorptionsverhalten von Wänden quantifiziert werden. Der vorgestellte Ansatz der globalen Admittanzbestimmung in Innenräumen ermöglicht die Berücksichtigung schrägen Schalleinfalls. Die Methode sieht ein Experiment vor, bei dem das Schallfeld mit Mikrofonen abgetastet, alle vorhandenen Schallquellen bestimmt sowie die Geometrie des akustischen Raumes erfasst werden. Mit den in der Arbeit entwickelten Algorithmen wird eine globale Admittanzverteilung für den gesamten Rand aus diesen Daten berechnet. Mit Hilfe erfolgreich identifizierter Admittanzverläufe sollen Simulationen niederfrequenter Wellenausbreitungen in Räumen auch komplizierter Geometrien und Oberflächenbeschaffenheiten durch Hinzunahme von Admittanzrandbedingungen ermöglicht und verbessert werden. Die Bestimmung von Wandadmittanzen aus partiell bekannten Schalldruckwerten wird mathematisch als inverses Problem eingeordnet. Für die inversen Algorithmen werden die Methoden der Randelemente (BE) und der finiten Elemente (FE) zur Diskretisierung des akustischen Randwertproblems verwendet. Aus den Gleichungen der BE-Diskretisierung lässt sich ein schlecht konditioniertes, aber dafür lineares Gleichungssystem für das inverse Problem finden, während die FE-basierte Formulierung ein nichtlineares, aufgrund der Komplexität des Problems meist ebenfalls schlecht konditioniertes Optimierungsproblem darstellt. Ein wesentliches Ergebnis dieser Arbeit ist die Gegenüberstellung der linearen und nichtlinearen Algorithmen des inversen Problems in Hinblick auf deren Herleitungen, die umgesetzten Berechnungsverfahren und der sich stark unterscheidenden Lösungsqualitäten. Untersuchungen der Admittanzrekonstruktion an zwei- und dreidimensionalen theoretischen Modellen verdeutlichen die Einflüsse der Modellgenauigkeit, des Messumfanges und des Messrauschens auf die Ergebnisse der inversen Algorithmen. Anhand der Anwendung auf Messdaten eines bei Brüel & Kjaer durchgeführten Experimentes wird das inverse Verfahren der globalen Admittanzbestimmung einem Praxistest unterzogen. / Reflection and absorption of sound waves on boundaries play a determining role for the optimization of acoustical properties in closed rooms. Above all the geometry and dynamic behavior of the wall structure are responsible for it. These boundary terms are quantifiable within the scope of numerical acoustics by the so-called admittance boundary conditions of the acoustical boundary value problem. Especially at low frequencies the quality of acoustical simulation depends strongly on the recognition of boundary admittances. The present work includes the development of two different inverse algorithms based on deterministic discretization methods for the global determination of frequency-dependent boundary admittance parameters. The approach of global determination of admittances allows to take account for non-perpendicular wave incident. For the method to work an experiment shall be initially conducted. In that process all present sound sources and microphone arrays scanning the sound field must be located and measured and a model of the geometry of the room needs to be created. The developed algorithms calculate then a global admittance distribution based on this data. Using successfully identified admittance characteristics as admittance boundary condition, low frequency simulation in rooms of complex geometry and arbitrary consistency of the surface shall be improved. Identifying boundary admittances out of partially measured sound pressure data is classifiable as inverse acoustic problem. In order to develop inverse formulations the acoustical boundary value problem is discretized by means of the Boundary Element and the Finite Element Method. The inverse formulation of the Boundary Element equations composes an ill-posed but linear system of equations. In contrast, based on Finite Elements only a nonlinear optimization problem can be set up that often features a bad condition due to the complexity of the inverse problem. The comparison of these linear and nonlinear algorithms of the inverse acoustic problem of global determination of boundary admittances in respect of derivation, implemented solution techniques and differing solution qualities states an essential result of this work. The investigation of admittance reconstruction at two and three-dimensional theoretical models reveal the influences of model accuracy, measurement expense and noise on measured data onto the results of both inverse algorithms. Finally, the problem of global admittance determination is subjected to experimentally obtained data (at Brüel & Kjaer) in order to check for practical applicability.

<div>Biodiversity loss is the silent crisis of the 21st century. Human activities are drastically altering the diversity of life on Earth, yet the extent of this transformation is shrouded by our limited information on biodiversity and how it is changing. Emerging technologies may be suited to fill this information gap, and as a result increase our capacity to measure and manage natural systems. Acoustic monitoring is a remote sensing technique that is rapidly reshaping the temporal and spatial scales with which we can assess animal biodiversity. Through recording and analyzing soundscapes—the collection of sounds occurring at a given place and time—we can assess biodiversity, habitat condition, and environmental change. However, the relationships between soundscapes and these three ecological dimensions are still in the early phases of categorization, especially in aquatic systems. </div><div><br></div><div>This dissertation investigates how soundscapes can be used to measure biodiversity, habitat condition, and environmental change in aquatic habitats. It addresses several knowledge gaps: First, I develop a framework for classifying unknown sounds within a soundscape, which I use to measure the acoustic diversity and dynamics within a tropical freshwater wetland. Second, I demonstrate that soundscapes can reflect the resilience of animal communities following disturbance events. Altered soundscapes revealed that Hurricane Maria, which swept through Puerto Rico in September 2017, impacted dry forest animal communities more than adjacent coral reef communities. Third, in kelp forest habitats off the coast of California, USA, I showed that soundscape variables correlated with ecological variables associated with regime shift in kelp forests, including urchin density, kelp cover, and fish diversity. Overall, this dissertation demonstrates that soundscape recording and analysis is a promising way to assess the ecological conditions of aquatic systems. </div>

Outdoor heating, ventilating, and air-conditioning (HVAC) units emit a significant amount of noise, which may lead to poor sound quality and a perceived low product quality. It is the job of the noise control engineer to reduce the undesired noise and improve the sound quality of the outdoor HVAC unit to decrease consumer annoyance. There is great interest in developing a detailed and accurate acoustic model of the outdoor HVAC unit so that the sound of the outdoor HVAC unit can be listened to before the unit is constructed. Having an acoustic model which can synthesize sounds allows the noise control engineer to evaluate and improve the sound quality of the outdoor HVAC unit during the design process, without the need for extensive prototyping. Acoustical holography methods will be used to identify and localize noise due to the fan, and other significant noise sources, to visualize the sound field. In the current study, an acoustic model is described which can be used to model the noise due to structural radiation and vortex shedding of the outdoor HVAC unit’s rotating fan blades, one of the top contributors to the unit’s overall noise level. This moving source model simulates the Doppler effect which occurs when the blade moves towards and away from a receiver. The results from this moving source model is shown for different source signals, including sinusoidal, bandpass random, repeating random, and sinusoidal with time-varying frequency source signals. The parameters of this moving source model will be optimized to reproduce the experimental results, including the power spectral densities, tonal power component, and auralizations.

Modular construction of housing is an industry on the rise. The prefabrication of construction modules gives a greater control over material consumption, promotes standardization, and lessens the disturbance during the construction time in the field. Lindbäcks Bygg AB prefabricates housing modules in their factory at Haraholmen, Piteå. The modules are then transported to construction sites all over the country and assembled. Lindbäcks Bygg AB has made the design choice to focus on lightweight wooden constructions for their modules, which comes with its own set of challenges. The urban densification of our city regions has led to more and more residential building being planned and constructed in areas that are submitted to high noise levels from surrounding traffic. This puts a great strain on the sound reduction of the building’s façade wall construction, something that has proven to be a problem with lightweight wooden walls. The aim of this master thesis project has been to test different solutions for lightweight façade wall constructions, and to ultimately find one or more solution that meet the requirements of the Swedish standards and regulations, as well as the needs of the tenants, and that can be implemented by Lindbäcks Bygg AB for manufacturing and assembly. The project has therefore been carried out in two parts, one theoretical and one practical. The theoretical part has verified the problem with traffic noise levels in residential buildings and identified the critical areas of the current façade construction. The theoretical work led to a list of defining factors for the sound reduction, which in turn worked as a basis for the ideation process.  As a result, the theoretical part led to a number of different construction concepts for façade walls. The concepts were first tested theoretically through modelling and calculation, and verified with the acousticians at Tyréns Sverige AB and the engineers of Lindbäcks Bygg AB. The most promising concepts were sent on to be manufactured. The practical part of this master thesis project was carried out mainly as acoustical measurements and the subsequent analysis, where the manufactured façade wall constructions were mounted on a free-standing module. The result of the practical part, and of the master thesis project, were four different façade wall constructions that met the requirements for noise reduction, which were presented to Lindbäcks Bygg AB and Tyréns Sverige AB. The construction most easily implemented is a construction with an airgap between the wall panels, and this construction will now have to be structurally verified and adapted for the factory, before being utilized in future building projects. / Modulärt byggande av bostäder är en bransch på frammarsch. Prefabricering av byggnadsmoduler ger en större kontroll över materialåtgången, främjar standardisering och minskar störningarna under byggtiden i fält. Lindbäcks Bygg AB prefabricerar bostadsmoduler i sin fabrik på Haraholmen, Piteå. Modulerna transporteras sedan till byggarbetsplatser över hela landet och monteras till bostadskomplex. Lindbäcks Bygg AB har gjort designvalet att fokusera på lätta träkonstruktioner för sina moduler, vilket kommer med sin egen uppsättning utmaningar. Förtätningen av våra stadsregioner har lett till att allt mer bostadsbyggande planeras och uppförs i områden som utsätts för höga bullernivåer från omgivande trafik. Detta utsätter byggnadens fasadväggskonstruktion för en stor akustisk belastning, något som har visat sig vara ett problem med lätta träväggar. Syftet med detta examensarbete har varit att testa olika lösningar för lätta fasadväggskonstruktioner, och att i slutändan hitta en eller flera lösningar som uppfyller kraven i svenska standarder och föreskrifter samt hyresgästernas behov, och som kan implementeras av Lindbäcks Bygg AB för tillverkning och montering. Projektet har därför genomförts i två delar, en teoretisk och en praktisk. Den teoretiska delen har verifierat problemet med trafikbullernivåer i bostadshus och identifierat kritiska områden i den nuvarande fasadkonstruktionen. Det teoretiska arbetet ledde fram till en lista med kritiska faktorer för ljudreduktionen, som i sin tur fungerade som grund för designprocessen. Som ett resultat ledde den teoretiska delen till en rad olika konstruktionskoncept för fasadväggar. Koncepten testades först teoretiskt genom modellering och beräkning, och verifierades av akustikerna på Tyréns Sverige AB och ingenjörerna på Lindbäcks Bygg AB. De mest lovande koncepten skickades vidare för tillverkning. Den praktiska delen av detta examensarbete genomfördes främst som akustiska mätningar och efterföljande analys, där de tillverkade fasadväggkonstruktionerna monterades på en fristående modul. Resultatet av den praktiska delen, och av examensarbetet, blev fyra olika fasadväggskonstruktioner som uppfyller kraven för ljudreduktion, vilka presenterades för Lindbäcks Bygg AB och Tyréns Sverige AB. Den konstruktion som är enklast att implementera är en konstruktion med luftspalt mellan väggpanelerna, och denna konstruktion kommer nu att behöva verifieras med avseende på ex. hållfasthet och anpassas för fabriken, innan den kan användas i framtida byggprojekt.

Indiana University-Purdue University Indianapolis (IUPUI) / Highway noise can cause annoyance, affect sleep patterns, and reduce the property value for people in the proximity. Current methods for analyzing the effectiveness of sound barriers only take loudness into consideration. This paper introduces new methods that can be used to analyze the effectiveness of the sound barriers. Our approach uses psychoacoustic measures including sharpness, roughness, fluctuation, strength, and annoyance. Highway noise is non-stationary, therefore each of these metrics are calculated over a short time. Finally analysis is performed the distribution and change over time. We used nth nearest neighbor algorithm to remove sounds that are not a part of the experiment. In the future, this data can be combined with human surveys to see if the change in sound quality due to the presence of sound barriers has a meaningful impact on people's lives.

Since the 1950s the jet aeroacoustics community has been involved in predicting and measuring the noise distribution in jets. In this work, cylindrical and planar Fourier near-field acoustical holography are used to investigate radiation from a full-scale, installed jet engine. Practical problems involving measurement aperture and the highly directional nature of the source are addressed. Insights from numerical simulations reveal usable reconstruction regions. A comparison of cylindrical and planar NAH for the respective measurement apertures shows cylindrical NAH outperforms planar NAH on reconstructions both towards and away from the source.

This thesis discusses the aero-acoustic characterisation of a perforate sample using a three-port technique. A rectangular T-junction with a flush mounted perforated sample at the intersection form the acoustical three-port. Under acoustic excitation from three different directions a direct method of impedance determination is incorporated to experimentally determine the passive acoustic properties of the perforate. The three-port scattering matrix and the normalised transfer impedance are calculated in the presence of grazing flow and for high-level excitation and the behaviour of these characteristics is studied. Validation of the determined results in the linear range is carried out by comparing it with existing models. Moreover, based on the experimental results for low grazing flow velocities the dependence of the real part of the transfer impedance on the grazing flow parameters as well as dimensionless numbers is described, and a semi-empirical model quantifying the behaviour is proposed. Furthermore, the thesis explains some experimental errors pertaining to standing wave patterns and operating conditions, and corrections are suggested to reduce the errors. / <p>QC 221007</p>

L'une des difficultés d'une langue peu dotée est l'inexistence des services liés aux technologies du traitement de l'écrit et de l'oral. Dans cette thèse, nous avons affronté la problématique de l'étude acoustique de la parole isolée et de la parole continue en Fongbe dans le cadre de la reconnaissance automatique de la parole. La complexité tonale de l'oral et la récente convention de l'écriture du Fongbe nous ont conduit à étudier le Fongbe sur toute la chaîne de la reconnaissance automatique de la parole. En plus des ressources linguistiques collectées (vocabulaires, grands corpus de texte, grands corpus de parole, dictionnaires de prononciation) pour permettre la construction des algorithmes, nous avons proposé une recette complète d'algorithmes (incluant des algorithmes de classification et de reconnaissance de phonèmes isolés et de segmentation de la parole continue en syllabe), basés sur une étude acoustique des différents sons, pour le traitement automatique du Fongbe. Dans ce manuscrit, nous avons aussi présenté une méthodologie de développement de modèles accoustiques et de modèles du langage pour faciliter la reconnaissance automatique de la parole en Fongbe. Dans cette étude, il a été proposé et évalué une modélisation acoustique à base de graphèmes (vu que le Fongbe ne dispose pas encore de dictionnaire phonétique) et aussi l'impact de la prononciation tonale sur la performance d'un système RAP en Fongbe. Enfin, les ressources écrites et orales collectées pour le Fongbe ainsi que les résultats expérimentaux obtenus pour chaque aspect de la chaîne de RAP en Fongbe valident le potentiel des méthodes et algorithmes que nous avons proposés. / One of the difficulties of an unresourced language is the lack of technology services in the speech and text processing. In this thesis, we faced the problematic of an acoustical study of the isolated and continous speech in Fongbe as part of the speech recognition. Tonal complexity of the oral and the recent agreement of writing the Fongbe led us to study the Fongbe throughout the chain of an automatic speech recognition. In addition to the collected linguistic resources (vocabularies, large text and speech corpus, pronunciation dictionaries) for building the algorithms, we proposed a complete recipe of algorithms (including algorithms of classification and recognition of isolated phonemes and segmentation of continuous speech into syllable), based on an acoustic study of the different sounds, for Fongbe automatic processing. In this manuscript, we also presented a methodology for developing acoustic models and language models to facilitate speech recognition in Fongbe. In this study, it was proposed and evaluated an acoustic modeling based on grapheme (since the Fongbe don't have phonetic dictionary) and also the impact of tonal pronunciation on the performance of a Fongbe ASR system. Finally, the written and oral resources collected for Fongbe and experimental results obtained for each aspect of an ASR chain in Fongbe validate the potential of the methods and algorithms that we proposed.