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Acoustic metamaterials comprised of dead-end pores and black hole effect for low frequency sound absorption in linear and nonlinear regimes (2021)
Thesis
Brooke, D. Acoustic metamaterials comprised of dead-end pores and black hole effect for low frequency sound absorption in linear and nonlinear regimes. (Thesis). University of Salford

The aim of this work is to design and test acoustic metamaterial absorbers particularly for mitigation of
low frequency sound of high intensity. The absorbers designed are formed of a series of plates with a
central perforation, separated by air... Read More about Acoustic metamaterials comprised of dead-end pores and black hole effect for low frequency sound absorption in linear and nonlinear regimes.

Acoustic metamaterial for low frequency sound absorption in linear and nonlinear regimes (2020)
Journal Article
Brooke, D., Umnova, O., Leclaire, P., & Dupont, T. (2020). Acoustic metamaterial for low frequency sound absorption in linear and nonlinear regimes. Journal of Sound and Vibration, 485, 115585. https://doi.org/10.1016/j.jsv.2020.115585

Acoustic metamaterial absorbers have been built and tested with
focus on low frequency airborne sound absorption in linear and nonlinear
regimes. The absorbers are made up of a series of piled up flat cavities,
separated by thin walls and traverse... Read More about Acoustic metamaterial for low frequency sound absorption in linear and nonlinear regimes.

Nonlinear dynamics of coupled transverse-rotational waves in granular chains (2019)
Journal Article
Zhang, Q., Umnova, O., & Venegas, R. (2019). Nonlinear dynamics of coupled transverse-rotational waves in granular chains. Physical Review E, 100(6), 062206. https://doi.org/10.1103/PhysRevE.100.062206

The nonlinear dynamics of coupled waves in one-dimensional granular chains with and without a substrate
is theoretically studied accounting for quadratic nonlinearity. The multiple time scale method is used to derive
the nonlinear dispersion relati... Read More about Nonlinear dynamics of coupled transverse-rotational waves in granular chains.

Detection of osteoporosis from percussion responses using an electronic stethoscope and machine learning (2018)
Journal Article
Scanlan, J., Li, F., Umnova, O., Rakoczy, G., Lövey, N., & Scanlan, P. (2018). Detection of osteoporosis from percussion responses using an electronic stethoscope and machine learning. Bioengineering, 5(4), 107. https://doi.org/10.3390/bioengineering5040107

Osteoporosis is an asymptomatic bone condition that affects a large proportion of the elderly population around the world, resulting in increased bone fragility and increased risk of fracture. Previous studies had shown that the vibroacoustic respons... Read More about Detection of osteoporosis from percussion responses using an electronic stethoscope and machine learning.

Nonlocal boundary conditions for corrugated acoustic metasurface with strong near field interactions (2018)
Journal Article
Schwan, L., Umnova, O., Boutin, C., & Groby, J. (2018). Nonlocal boundary conditions for corrugated acoustic metasurface with strong near field interactions. Journal of Applied Physics, 123, 091712. https://doi.org/10.1063/1.5011385

The propagation of long-wavelength sound in the presence of a metasurface made by arranging acoustic resonators periodically upon or slightly above an impervious substrate is studied. The method of two-scale asymptotic homogenization is used to deriv... Read More about Nonlocal boundary conditions for corrugated acoustic metasurface with strong near field interactions.

Acoustics of multiscale sorptive porous materials (2017)
Journal Article
Venegas, R., Boutin, C., & Umnova, O. (2017). Acoustics of multiscale sorptive porous materials. Physics of Fluids, 29(8), 082006. https://doi.org/10.1063/1.4999053

This paper investigates sound propagation in multiscale rigid-frame porous materials that support mass transfer processes, such as sorption and different types of diffusion, in addition to the usual visco-thermo-inertial interactions. The two-scale a... Read More about Acoustics of multiscale sorptive porous materials.

Influence of diffusion and sorption on sound propagation in multiscale porous materials (2017)
Presentation / Conference
Venegas, R., Boutin, C., & Umnova, O. (2017, July). Influence of diffusion and sorption on sound propagation in multiscale porous materials. Presented at 6th Biot Conference on Poromechanics, Paris, France

This paper investigates sound propagation in multiscale sorptive porous materials saturated with a pure gas. An example of this type of materials is a packing of porous grains where a mesoscopic, microscopic, and nanoscopic scale can be identified. T... Read More about Influence of diffusion and sorption on sound propagation in multiscale porous materials.

Influence of sorption on sound propagation in granular activated carbon (2016)
Journal Article
Venegas, R., & Umnova, O. (2016). Influence of sorption on sound propagation in granular activated carbon. ˜The œJournal of the Acoustical Society of America (Online), 140(2), 755-766. https://doi.org/10.1121/1.4959006

Granular activated carbon (GAC) has numerous applications due to its ability to adsorb and desorb
gas molecules. Recently, it has been shown to exhibit unusually high low frequency sound absorption.
This behavior is determined by both the multi-sca... Read More about Influence of sorption on sound propagation in granular activated carbon.

Acoustical properties of air-saturated porous material with periodically distributed dead-end pores (2015)
Journal Article
with periodically distributed dead-end pores. ˜The œJournal of the Acoustical Society of America (Online), 137(4), 1772-1782. https://doi.org/10.1121/1.4916712

A theoretical and numerical study of the sound propagation in air-saturated porous media with
straight main pores bearing lateral cavities (dead-ends) is presented. The lateral cavities are located
at “nodes” periodically spaced along each main por... Read More about Acoustical properties of air-saturated porous material with periodically distributed dead-end pores.

Omnidirectional acoustic absorber with a porous core and a metamaterial matching layer (2014)
Journal Article
layer. Journal of Applied Physics, 115(20), 204902. https://doi.org/10.1063/1.4876119

An omnidirectional sound absorber based on the acoustic analogy of the electromagnetic metamaterial
“black hole” has been developed and tested. The resulting structure is composed of a hollow
cylindrical porous absorbing core and a graded index mat... Read More about Omnidirectional acoustic absorber with a porous core and a metamaterial matching layer.

Absorption of sound by porous layers with embedded periodic arrays of resonant inclusions (2013)
Journal Article
arrays of resonant inclusions. ˜The œJournal of the Acoustical Society of America (Online), 134(6), 4670-4680. https://doi.org/10.1121/1.4824843

The aim of this work is to design a layer of porous material with a high value of the absorption
coefficient in a wide range of frequencies. It is shown that low frequency performance can be
significantly improved by embedding periodically arranged... Read More about Absorption of sound by porous layers with embedded periodic arrays of resonant inclusions.

Influence of Forchheimer’s nonlinearity and transient effects on pulse propagation in air saturated rigid granular materials (2013)
Journal Article
Turo, D., & Umnova, O. (2013). Influence of Forchheimer’s nonlinearity and transient effects on pulse propagation in air saturated rigid granular materials. ˜The œJournal of the Acoustical Society of America (Online), 134(6), 4763. https://doi.org/10.1121/1.4824969

It has been shown in the earlier work of Umnova et al. [Noise Control Eng. 50, 204–210 (2002)]
that interaction of a relatively long, high amplitude acoustic pulse with a rigid porous material can
be accurately described accounting for the Forchhei... Read More about Influence of Forchheimer’s nonlinearity and transient effects on pulse propagation in air saturated rigid granular materials.

Comparisons of two effective medium approaches for predicting sound scattering by periodic arrays of elastic shells (2013)
Journal Article
sound scattering by periodic arrays of elastic shells. ˜The œJournal of the Acoustical Society of America (Online), 134(5), 3619-3630. https://doi.org/10.1121/1.4824340

Two effective medium models are presented and used to predict complex reflection and transmission
coefficients of finite periodic arrays of resonant elastic shells as well as their effective density
and bulk modulus at low frequencies. Comparisons... Read More about Comparisons of two effective medium approaches for predicting sound scattering by periodic arrays of elastic shells.

Analytical approximations for low frequency band gaps in periodic arrays of elastic shells (2013)
Journal Article
in periodic arrays of elastic shells. ˜The œJournal of the Acoustical Society of America (Online), 133(2), https://doi.org/10.1121/1.4773257

This paper presents and compares three analytical methods for calculating low frequency band
gap boundaries in doubly periodic arrays of resonating thin elastic shells. It is shown that both
Foldy-type equations (derived with lattice sum expansions... Read More about Analytical approximations for low frequency band gaps in periodic arrays of elastic shells.

Low frequency sound propagation in activated carbon (2012)
Journal Article
Bechwati, F., Avis, M., Bull, D., Cox, T., Hargreaves, J., Moser, D., …Venegas, R. (2012). Low frequency sound propagation in activated carbon. https://doi.org/10.1121/1.4725761

Activated carbon can adsorb and desorb gas molecules onto and off its surface. Research has examined
whether this sorption affects low frequency sound waves, with pressures typical of audible
sound, interacting with granular activated carbon. Imped... Read More about Low frequency sound propagation in activated carbon.

Acoustical properties of double porosity granular materials (2011)
Journal Article
Venegas, R., & Umnova, O. (2011). Acoustical properties of double porosity granular materials. ˜The œJournal of the Acoustical Society of America (Online), 130(5), 2765-2776. https://doi.org/10.1121/1.3644915

Granular materials have been conventionally used for acoustic treatment due to their sound absorptive
and sound insulating properties. An emerging field is the study of the acoustical properties of
multiscale porous materials. An example of these i... Read More about Acoustical properties of double porosity granular materials.

Volumetric diffusers : pseudorandom cylinder arrays on a periodic lattice (2010)
Journal Article
Hughes, R., Angus, J., Cox, T., Umnova, O., Gehring, G., Pogson, M., & Whittaker, D. (2010). Volumetric diffusers : pseudorandom cylinder arrays on a periodic lattice. ˜The œJournal of the Acoustical Society of America (Online), 128(5), 2847-2856. https://doi.org/10.1121/1.3493455

Most conventional diffusers take the form of a surface based treatment, and as a result can only operate in hemispherical space. Placing a diffuser in the volume of a room might provide greater efficiency by allowing scattering into the whole space.... Read More about Volumetric diffusers : pseudorandom cylinder arrays on a periodic lattice.

Effect of boundary slip on the acoustical properties of microfibrous materials (2009)
Journal Article
Umnova, O., Tsiklauri, D., & Venegas Castillo, R. (2009). Effect of boundary slip on the acoustical properties of microfibrous materials. ˜The œJournal of the Acoustical Society of America (Online), 126(4), 1850-1861. https://doi.org/10.1121/1.3204087

A variety of new porous materials with unusually small pores have been manufactured in the past decades. To predict their acoustical properties, the conventional models need to be modified. When pore size becomes comparable to the molecular mean free... Read More about Effect of boundary slip on the acoustical properties of microfibrous materials.

Effects of porous covering on sound attenuation by periodic arrays of cylinders. (2006)
Journal Article
Umnova, O., Attenborough, C., & Linton, J. (2006). Effects of porous covering on sound attenuation by periodic arrays of cylinders. ˜The œJournal of the Acoustical Society of America (Online), 119(1), 278-284. https://doi.org/10.1121/1.2133715

The acoustic transmission loss of a finite periodic array of long rigid cylinders, without and with porous absorbent covering, is studied both theoretically and in the laboratory. A multiple scattering model is extended to allow for the covering and... Read More about Effects of porous covering on sound attenuation by periodic arrays of cylinders..

Deduction of tortuosity and porosity from acoustic reflection and transmission measurements on thick samples of rigid-porous materials (2005)
Journal Article
Umnova, O., Attenborough, K., Shin, H., & Cummings, A. (2005). Deduction of tortuosity and porosity from acoustic reflection and transmission measurements on thick samples of rigid-porous materials. Applied Acoustics, 66(6), 607-624. https://doi.org/10.1016/j.apacoust.2004.02.005

An acoustic method for obtaining the tortuosity, and porosity of thick samples of rigid porous materials consisting of large (>1 mm) grains or fibres is proposed. The method uses pulses with central frequencies close to 12 kHz and an approximate... Read More about Deduction of tortuosity and porosity from acoustic reflection and transmission measurements on thick samples of rigid-porous materials.