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Output search results for "Umnova" (31)

Multiple resonances in lossy acoustic black holes - theory and experiment (2022)
Journal Article
Umnova, O., Brooke, D., Leclaire, P., & Dupont, T. (2022). Multiple resonances in lossy acoustic black holes - theory and experiment. Journal of Sound and Vibration, 543, https://doi.org/10.1016/j.jsv.2022.117377

Acoustic properties of the metamaterial graded absorber, also known as ``acoustic black hole'', are studied in the linear regime. The absorber consists of thin metallic circular plates, each with a central perforation, separated by annular air caviti... Read More about Multiple resonances in lossy acoustic black holes - theory and experiment.

Acoustic wave propagation in permeable lossy metamaterials (2022)
Journal Article
Venegas, R., Núñez, G., Boutin, C., Umnova, O., & Zhang, Q. (2022). Acoustic wave propagation in permeable lossy metamaterials. Physics of Fluids, 34(1), 017117. https://doi.org/10.1063/5.0077342

This paper investigates acoustic wave propagation in gas-saturated permeable lossy metamaterials, which have different types of resonators, namely, acoustic and elastic resonators, as building-block elements. By using the two-scale asymptotic homogen... Read More about Acoustic wave propagation in permeable lossy metamaterials.

Low frequency sound absorption in a porous material with periodically distributed dead-end pores
Presentation / Conference
Leclaire, P., Umnova, O., Dupont, T., & Panneton, R. Low frequency sound absorption in a porous material with periodically distributed dead-end pores. Presented at EuroNoise 2015, Maastricht, Netherlands

A theoretical and numerical study of the sound propagation in air-saturated porous media with straight pores bearing lateral cavities (dead-ends) is proposed. The straight pores can be considered as the main (Biot) pores. The lateral cavities are loc... Read More about Low frequency sound absorption in a porous material with periodically distributed dead-end pores.

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.

Machine learning and DSP algorithms for screening of possible osteoporosis using electronic stethoscopes (2018)
Presentation / Conference
Scanlan, J., Li, F., Umnova, O., Rakoczy, G., & Lövey, N. (2018, October). Machine learning and DSP algorithms for screening of possible osteoporosis using electronic stethoscopes. Presented at 3rd International Conference on Biomedical Imaging, Signal Processing (ICBSP 2018), Polytechnic University of Bari, Italy

Osteoporosis is a prevalent but asymptomatic condition that affects a large population of the elderly, resulting in a high risk of fracture. Several methods have been developed and are available in general hospitals to indirectly assess the bone qual... Read More about Machine learning and DSP algorithms for screening of possible osteoporosis using electronic stethoscopes.

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.

Sound absorption and reflection from a resonant metasurface : homogenization model with experimental validation (2017)
Journal Article
Schwan, L., Umnova, O., & Boutin, C. (2017). Sound absorption and reflection from a resonant metasurface : homogenization model with experimental validation. Wave Motion, 72, 154-172. https://doi.org/10.1016/j.wavemoti.2017.02.004

Efficient manipulation of sound waves by some resonant acoustic metasurface designs has recently been reported in the literature. This paper presents a general theoretical framework for the description of sound wave interaction with the resonant meta... Read More about Sound absorption and reflection from a resonant metasurface : homogenization model with experimental validation.

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.

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.

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.

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.

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.

Behavior of rigid – porous layers at high levels of continuous acoustic excitation: Theory and experiment (2003)
Journal Article
Umnova, O., Attenborough, K., Cummings, A., & Standley, E. (2003). Behavior of rigid – porous layers at high levels of continuous acoustic excitation: Theory and experiment. ˜The œJournal of the Acoustical Society of America (Online), 114(3), 1346-1356. https://doi.org/10.1121/1.1603236

A model for the propagation of high amplitude continuous sound through hard-backed rigid-porous layers has been developed which allows for Forchheimer's correction to Darcy's law. The nonlinearity associated with this is shown to be particularly impo... Read More about Behavior of rigid – porous layers at high levels of continuous acoustic excitation: Theory and experiment.

Response of multiple rigid porous layers to high levels of continuous acoustic excitation (2004)
Journal Article
Umnova, O., Attenborough, K., Shin, H., & Cummings, A. (2004). Response of multiple rigid porous layers to high levels of continuous acoustic excitation. https://doi.org/10.1121/1.1766051

A model has been developed for the response of a rigid-porous hard-backed medium containing an arbitrary number of layers to high amplitude sound. Nonlinearity is introduced by means of a velocity-dependent flow resistivity in Johnson's equivalent fl... Read More about Response of multiple rigid porous layers to high levels of continuous acoustic excitation.

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.

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..

Predictions and measurements of sound transmission through a periodic array of elastic shells in air (2010)
Journal Article
a periodic array of elastic shells in air. ˜The œJournal of the Acoustical Society of America (Online), 128, 3496. https://doi.org/10.1121/1.3506342

Analytical and numerical approaches have been made to the problems of (a) propagation through a doubly periodic array of elastic shells in air, (b) scattering by a single elastic shell in air, and (c) scattering by a finite periodic array of elastic... Read More about Predictions and measurements of sound transmission through a periodic array of elastic shells in air.

Nonlinear behaviour of lossy acoustic black holes (2024)
Journal Article
Umnova, O., Brooke, D., Leclaire, P., & Dupont, T. (in press). Nonlinear behaviour of lossy acoustic black holes. #Journal not on list, https://doi.org/10.61782/fa.2023.0652

Sound absorption properties of acoustic black holes are studied for high pressure amplitudes. The absorbers consist of thin circular plates, each with a central perforation, separated by annular air cavities. Radius of the perforation of each plate d... Read More about Nonlinear behaviour of lossy acoustic black holes.

FE Modelling Tibia Bone Vibration - The Influence of Shape, Twist, and Size (2024)
Journal Article
Scanlan, J., Umnova, O., & Li, F. (in press). FE Modelling Tibia Bone Vibration - The Influence of Shape, Twist, and Size. #Journal not on list, https://doi.org/10.61782/fa.2023.1141

The vibration response of bone has the potential to be used as a measure of bone strength for Osteoporosis detection. Modelling the vibration response requires capturing the shape of the long bones which have several complicated features. Yet modelli... Read More about FE Modelling Tibia Bone Vibration - The Influence of Shape, Twist, and Size.

Urban Hedges as Noise Barriers: Does Plant Species Choice Affect Insertion Loss? (2024)
Journal Article
Webb, J., Cox, T., Blanusa, T., Griffiths, A., & Umnova, O. (in press). Urban Hedges as Noise Barriers: Does Plant Species Choice Affect Insertion Loss?. #Journal not on list, https://doi.org/10.61782/fa.2023.1152

Noise in urban environments is responsible for annoyance and adverse health effects. Noise barriers are used to mitigate noise and are effective when properly designed and installed, but provide little visual or biodiversity benefit. Hedges are frequ... Read More about Urban Hedges as Noise Barriers: Does Plant Species Choice Affect Insertion Loss?.