Experimental Study on the Effect of Air Gap, Thickness, and Density on Acoustic Impedance and Sound Absorption of Stone Wool and Rubber Samples with Transfer Function Method

Forouharmajd, Farhad; Mohammadi, Zahra

doi:10.1007/s40997-017-0078-0

Cited by 7 publications

(3 citation statements)

References 12 publications

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“…In such cases, applying sound quality or psychoacoustic criteria in such cases seems more logical. [ 5 6 7 ] Psychoacoustics determines the functional relationships between the physical properties of noise and auditory sensory phenomena. [ 8 ]…”

Section: Introductionmentioning

confidence: 99%

The Influence of Noise Exposure at Different Loudness Levels on EEG Index and Types of Attention

Mohammadi,

Jafari,

Khavanin

et al. 2023

International Journal of Preventive Medicine

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Bachground: Noise is one of the most important harmful factors in the environment. There are limited studies on the effect of noise loudness on brain signals and attention. The main objective of this study was to investigate the relationship between exposure to different loudness levels with brain index, types of attention, and subjective evaluation. Methods: Four noises with different loudness levels were generated. Sixty-four male students participated in this study. Each subject performed the integrated visual and auditory continuous performance test (IVA-2) test before and during exposure to noise loudness signals while their electroencephalography was recorded. Finally, the alpha-to-gamma ratio (AGR), five types of attention, and the subjective evaluation results were examined. Results: During exposure to loudness levels, the AGR and types of attention decreased while the NASA-Tax Load Index (NASA-TLX) scores increased. The noise exposure at lower loudness levels (65 and 75 phon) leads to greater attention dysfunction than at higher loudness. The AGR was significantly changed during exposure to 65 and 75 phon and audio stimuli. This significant change was observed in exposure at all loudness levels except 85 phon and visual stimuli. The divided and sustained attention changed significantly during exposure to all loudness levels and visual stimuli. The AGR had a significant inverse correlation with the total score of NASA-TLX during noise exposure. Conclusions: These results can lead to the design of methods to control the psychological effects of noise at specific frequencies (250 and 4000 Hz) and can prevent non-auditory damage to human cognitive performance in industrial and urban environments.

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Section: Introductionmentioning

confidence: 99%

The Influence of Noise Exposure at Different Loudness Levels on EEG Index and Types of Attention

Mohammadi,

Jafari,

Khavanin

et al. 2023

International Journal of Preventive Medicine

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“…The increased complexity in the sound pathway has provided more chances for the friction and reflection of sound waves among the fiber frames; thus, more sound energy would be consumed and the enhancement of sound absorption performance was realized . To demonstrate the superior sound absorption performance of the SBAs, we have compared the NRC and areal density of the as-prepared SBAs with those of previously reported inorganic porous sound absorption materials (made by glass fibers, porous zeolites, stone wool, carbon fibers, metal fibers, blast furnace slag, and recycled glass fibers). As shown in Figure b, the SBAs show obvious advantages of low density and high sound absorption performance.…”

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confidence: 99%

Fire-Resistant and Hierarchically Structured Elastic Ceramic Nanofibrous Aerogels for Efficient Low-Frequency Noise Reduction

et al. 2022

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Traffic noise has been regarded as one of the most annoying pollutions that induce severe hazards to human health, both physiological and psychological. The commonly used fibrous noise absorption materials are limited by their large density, poor sound absorption ability at low frequencies, and unsatisfactory fire-resistant ability. Here, we develop hierarchically structured elastic ceramic electrospun nanofibrous aerogels, which possess lightweight properties (density of 13.29 mg cm–3) and superior low-frequency sound absorption ability (NRC value of 0.59). Specifically, the obtained ceramic electrospun nanofibrous aerogel is nonflammable on exposure to fire and can be compressed and quickly recover to its original height without any visible damage. Moreover, the resultant aerogels could be facilely and efficiently manufactured into designed shapes on a large scale, demonstrating their potential for industrialization. The successful design of such ceramic-based bulk materials may provide new insights for the further development of the next-generation high-efficiency sound-absorbing products.

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“…Tem-se buscado conhecer e utilizar em construção civil materiais que tenham características acústica e calculáveis. Estudos mais recentes têm observado o comportamento acústicos de materiais não-convencionais, muitas vezes buscando a reutilização, a sustentabilidade e a redução de custos (FOROUHARMAJD, 2018;(GOMEZ ESCOBAR e MADERUELO-SANZ, 2017). Esses estudos também serão melhor detalhados afrente.…”

Section: Desafios Correntesunclassified

Análise dinâmica de modos de propagação sonora e projeto de instrumentação expandida para tubo de impedância

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Essa dissertação simboliza um ciclo de quase dez anos aprendendo, ensinando e convivendo com muitas pessoas na Escola de Engenharia de São Carlos da Universidade de São Paulo, a que devo meu amadurecimento enquanto ser humano, profissional e cientista.Agradeço aos meus pais, Rizete e Bosco, e ao meu irmão, Júnior, por terem investido suas confianças no meu potencial e, principalmente, por terem dado a oportunidade de me dedicar aos estudos e ao meu treinamento profissional. Infelizmente nem todas as pessoas têm as oportunidades que eu tive na vida. Por isso, sou eternamente grato.Agradeço aos amigos e amigas que me acompanharam nessa jornada, pelo apoio, por acreditarem em mim, por me ouvirem desabafar angústias e incertezas. Àqueles da graduação Palavras-chave: acústica; propagação sonora; equações diferenciais; tubo de impedância; instrumentação acústica.

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Experimental Study on the Effect of Air Gap, Thickness, and Density on Acoustic Impedance and Sound Absorption of Stone Wool and Rubber Samples with Transfer Function Method

Cited by 7 publications

References 12 publications

The Influence of Noise Exposure at Different Loudness Levels on EEG Index and Types of Attention

The Influence of Noise Exposure at Different Loudness Levels on EEG Index and Types of Attention

Fire-Resistant and Hierarchically Structured Elastic Ceramic Nanofibrous Aerogels for Efficient Low-Frequency Noise Reduction

Análise dinâmica de modos de propagação sonora e projeto de instrumentação expandida para tubo de impedância

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