Loudspeaker
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. A new and improved electric fish finder with resources for printed circuit board fabrication
RESUMO Nós descrevemos o projeto de circuitos eletrônicos e as instrucões para a construção e uso de um detector de peixes elétricos portátil (bio-amplificador diferencial de banda-larga com acoplamento AC). Este aparelho permite a detecção e o monitoramento das descargas de órgãos elétricos gerados por peixes neotropicais da ordem Gymnotiformes
Neotrop. ichthyol.. Publicado em: 25/11/2019
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2. On the distinctive call of a threatened phenotype of Allobates femoralis (Anura: Aromobatidae) and its recognition by allopatric conspecific males
ABSTRACT The brilliant-thighed frog [Allobates femoralis (Boulenger, 1884)]; is distributed across the Amazon basin and aggregates several allopatric evolutionary lineages, some of which present variation in their advertisement calls. In 2009, an unregistered call phenotype was discovered in the region of Altamira and Vitória do Xingu, State of Pará, Brazi
Iheringia, Sér. Zool.. Publicado em: 09/10/2017
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3. Approximate expressions for the reflection coefficient of ducts terminated by circular flanges
Estimating the magnitude of the pressure reflection coefficient |R| and the end correction l at the open end of ducts is a critical procedure when designing or predicting the acoustic behavior of acoustical systems, such as exhausts, tailpipes, mufflers, loudspeaker enclosures and so on. For cylindrical ducts and plane waves, exact intricate solutions exist
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-06
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4. Simulação de um arranjo esférico de alto-falantes usando um modelo de membrana flexível / Simulation of a spherical loudspeaker array using a flexible membrane model
Duas abordagens para a simulação do campo sonoro produzido por um arranjo esférico de alto-falantes são apresentadas e comparadas a resultados experimentais. Na primeira, modos estruturais obtidos da analise modal experimental da membrana são usados em simulações vibroacusticas por elementos de contorno no software LMS Virtual.Lab®. Na segunda, adota
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/08/2010
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5. Controle da diretividade sonora no espaço tridimensional por um arranjo esférico compacto de alto-falantes / Sound directivity control in a 3-D space by a compact spherical loudspeaker array
O controle angular da radiação sonora pode ser obtido utilizando um arranjo compacto de alto-falantes independentemente programáveis operando na mesma faixa de frequência. Geralmente, os alto-falantes são dispostos sobre uma estrutura de formato esférico seguindo a geometria de um sólido de Platão a fim de se obter uma configuração altamente simét
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/02/2010
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6. Contribuição a teoria e pratica da analise modal acustica experimental / A contribution to the theory and practice of experimental acoustic modal analysis
In the present work, a simple geometry (rectangular shallow cavity) is used to investigate the acoustic modal analysis methodology. Analytical and numerical models are developed for the comparison with the experimental results. Three types of excitation devices were constructed. One based on a shaker-driven piston and the other two using a driver loudspeaker
Publicado em: 2001
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7. Caracterização de fotodetetores para interferometria
Bandwidth and linearity are fundamental parameters in photodetectors behavior, and their knowledge is very important for most experiments in Optics. A new method for frequency response characterization is described in this work. This technique is based on Doppler velocimetry, where the vibration of a commercial loudspeaker in an interferometric setup is used
Publicado em: 1992
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8. A LOUD-SPEAKER STETHOSCOPE FOR CLINICAL TEACHING
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9. Effect of oral high frequency ventilation by jet or oscillator on minute ventilation in normal subjects.
Normal subjects were asked to breathe through an open ended tube while high frequency oscillations were superimposed on tidal breathing via a side arm, either an eight inch (20 cm) loudspeaker or a jet ventilator being used. Both systems were comfortable and well tolerated. Spontaneous minute ventilation fell by 19-46% at frequencies up to 33 Hz without a ri
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10. Acoustic imprinting leads to differential 2-deoxy-D-glucose uptake in the chick forebrain.
This report describes experiments in which successful acoustic imprinting correlates with differential uptake of D-2-deoxy[14C]glucose in particular forebrain areas that are not considered primarily auditory. Newly hatched guinea chicks (Numida meleagris meleagris) were imprinted by playing 1.8-kHz or 2.5-kHz tone bursts for prolonged periods. Those chicks w
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11. Development of fetal hearing
Previous research has revealed that the human fetus responds to sound, but to date there has been little systematic investigation of the development of fetal hearing. The development of fetal behavioural responsiveness to pure tone auditory stimuli (100 Hz, 250 Hz, 500 Hz, 1000 Hz, and 3000 Hz) was examined from 19 to 35 weeks of gestational age. Stimuli wer
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12. Increase in mucociliary clearance in normal man induced by oral high frequency oscillation.
Data on the effect on mucociliary clearance of oral high frequency oscillation is conflicting. By means of a technique to superimpose high frequency oscillation on tidal breathing, changes in mucociliary clearance during high frequency oscillation were studied in seven normal non-smokers by monitoring the clearance of inhaled radiolabelled aerosol from the l