Nonlinear self-collimated sound beams in sonic crystals

We report the propagation of high-intensity sound beams in a sonic crystal, under self-collimation or reduced-divergence conditions. The medium is a fluid with elastic quadratic nonlinearity, where the dominating nonlinear effect is harmonic generation. The conditions for the efficient generation of narrow, non-diverging beam of second harmonic are discussed. Numerical simulations are in agreement with the analytical predictions made, based on the linear dispersion characteristics in modulated media and the nonlinear interaction in a quadratic medium under phase matching conditions.Comment: Sent to PR

Enhancing resonant circular-section haloscopes for dark matter axion detection: approaches and limitations in volume expansion

Haloscopes, microwave resonant cavities utilized in detecting dark matter axions within powerful static magnetic fields, are pivotal in modern astrophysical research. This paper delves into the realm of cylindrical geometries, investigating techniques to augment volume and enhance compatibility with dipole or solenoid magnets. The study explores volume constraints in two categories of haloscope designs: those reliant on single cavities and those employing multicavities. In both categories, strategies to increase the expanse of elongated structures are elucidated. For multicavities, the optimization of space within magnets is explored through 1D configurations. Three subcavity stacking approaches are investigated, while the foray into 2D and 3D geometries lays the groundwork for future topological developments. The results underscore the efficacy of these methods, revealing substantial room for progress in cylindrical haloscope design. Notably, an elongated single cavity design attains a three-order magnitude increase in volume compared to a WC-109 standard waveguide-based single cavity. Diverse prototypes featuring single cavities, 1D, 2D, and 3D multicavities highlight the feasibility of leveraging these geometries to magnify the volume of tangible haloscope implementations

Ultradiscrete kinks with supersonic speed in a layered crystal with realistic potentials

We develop a dynamical model of the propagating nonlinear localized excitations, supersonic kinks, in the cation layer in a silicate mica crystal. We start from purely electrostatic Coulomb interaction and add the Ziegler-Biersack-Littmark short-range repulsive potential and the periodic potential produced by other atoms of the lattice. This approach allows the construction of supersonic kinks which can propagate in the lattice within a large range of energies and velocities. The interparticle distances in the lattice kinks with high energy are physically reasonable values. The introduction of the periodic lattice potential results in the important feature that the kinks propagate with a single velocity and a single energy which are independent on the excitation conditions. The found kinks are ultra-discrete and can be described with the "magic wave number" $q\simeq 2\pi/3a$, which was previously revealed in the nonlinear sinusoidal waves and supersonic kinks in the Fermi-Pasta-Ulam lattice. The extreme discreteness of the supersonic kinks, with basically two particles moving at the same time, allows the interpretation of their double-kink structure. The energy of the supersonic kinks is between the possible source of $^{40}$K recoil in beta decay and the energy necessary for the ejection of an atom at the border as has been found experimentally.Comment: 14 pages, 15 figure

Nonlinear waves in a chain of magnetically coupled pendula

A motivation for the study of reduced models like one-dimensional systems in Solid State Physics is the complexity of the full problem. In recent years our group has studied theoretically, numerically and experimentally wave propagation in lattices of nonlinearly coupled oscillators. Here, we present the dynamics of magnetically coupled pendula lattices. These macroscopic systems can model the dynamical processes of matter or layered systems. We report the results obtained for harmonic wave propagation in these media, and the different regimes of mode conversion into higher harmonics strongly influenced by dispersion and discreteness, including the phenomenon of acoustic dilatation of the chain, as well as some results on the propagation of localized waves i.e., solitons and kinks.Generalitat Valenciana APOSTD/2017/042Umiversitat Politècnica de València PAID-01-14Ministerio de Economía y Competitividad (MINECO), Spain FIS2015-65998-C2-2-PJunta de Andalucía 2017/FQM-28

Vibroacoustic effects of resonant sonic crystals in sound absorption

[EN] A resonant sonic crystal made of solid elastic clamped beams is experimentally analysed in this work. The sonic crystal studied in this work has three characteristics: (i) a low filling fraction, (ii) a high frequency Band Gap and (iii) resonant scatterers. Due to the properties (i) and (ii), the sonic crystal behaves as an equivalent fluid with acoustic properties very closed to ones of the air. This means that the crystal is almost impedance matched, being the crystal transparent to the incident waves. However, the resonant elements have a resonance frequency in the range analysed in this work, introducing an absorption peak due to the resonances produced by the vibroacoustic coupling. The two microphone transfer function method is used to measure the (complex) impedance and then to evaluate experimentally the absorption coefficient of the 2D SC made of a set of parallel solid beams in the low frequency regime.Authors ackowledge the support of the European Space Agency under the 441-2015 Co-Sponsored PhD "Acoustic Noise Reduction Methods for the Launch Pad"Herrero-Durá, I.; Picó Vila, R.; Sánchez Morcillo, VJ.; García-Raffi, LM.; Romero García, V. (2016). Vibroacoustic effects of resonant sonic crystals in sound absorption. Universidade do Porto. 1-7. http://hdl.handle.net/10251/181082S1

Formation of high-order acoustic Bessel beams by spiral diffraction gratings

The formation of high-order Bessel beams by a passive acoustic device consisting of an Archimedes' spiral diffraction grating is theoretically, numerically, and experimentally reported in this paper. These beams are propagation-invariant solutions of the Helmholtz equation and are characterized by an azimuthal variation of the phase along its annular spectrum producing an acoustic vortex in the near field. In our system, the scattering of plane acoustic waves by the spiral grating leads to the formation of the acoustic vortex with zero pressure on axis and the angular phase dislocations characterized by the spiral geometry. The order of the generated Bessel beam and, as a consequence, the size of the generated vortex can be fixed by the number of arms in the spiral diffraction grating. The obtained results allow for obtaining Bessel beams with controllable vorticity by a passive device, which has potential applications in low-cost acoustic tweezers and acoustic radiation force devices.We acknowledge financial support from MINECO of the Spanish Government under Grants No. MTM2012-36740-C02-02, No. FIS2015-65998-C2-1-P, and No. FIS2015-65998-C2-2-P. N.J. acknowledges financial support from PAID-2011 Universitat Politecnica de Valencia.Jimenez, N.; Picó Vila, R.; Sánchez Morcillo, VJ.; Romero García, V.; García-Raffi, LM.; Staliünas, K. (2016). Formation of high-order acoustic Bessel beams by spiral diffraction gratings. Physical Review E. 94(5). doi:10.1103/PhysRevE.94.053004S05300494

Natural sonic crystal absorber constituted of seagrass (Posidonia Oceanica) fibrous spheres

[EN] We present a 3-dimensional fully natural sonic crystal composed of spherical aggregates of fibers (called Aegagropilae) resulting from the decomposition of Posidonia Oceanica. The fiber network is first acoustically characterized, providing insights on this natural fiber entanglement due to turbulent flow. The Aegagropilae are then arranged on a principal cubic lattice. The band diagram and topology of this structure are analyzed, notably via Argand representation of its scattering elements. This fully natural sonic crystal exhibits excellent sound absorbing properties and thus represents a sustainable alternative that could outperform conventional acoustic materials.This article is based upon work from COST Action DENORMS CA15125, supported by COST(European Cooperation in Science and Technology). The authors gratefully acknowledge the ANR-RGC METARoom (ANR-18-CE08-0021) project, the project HYPERMETA funded under the program Etoiles Montantes of the Region Pays de la Loire, and the project PID2019-109175GB-C22 funded by the Spanish Ministry of Science and Innovation. N.J. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICINN) through grant "Juan de la Cierva - Incorporacion" (IJC2018-037897-I). The authors would like to thank V. Pagneux and R. Pico Vila for useful discussions and J. Barber and C. Dordoni for their help in collecting the samples.Barguet, L.; Romero-García, V.; Jimenez, N.; García-Raffi, LM.; Sánchez Morcillo, VJ.; Groby, J. (2021). Natural sonic crystal absorber constituted of seagrass (Posidonia Oceanica) fibrous spheres. Scientific Reports. 11(1):1-8. https://doi.org/10.1038/s41598-020-79982-9S1811

Sound absorption and diffusion by 2D arrays of Helmholtz resonators

[EN] We report a theoretical and experimental study of an array of Helmholtz resonators optimized to achieve both efficient sound absorption and diffusion. The analysis starts with a simplified 1D model where the plane wave approximation is used to design an array of resonators showing perfect absorption for a targeted range of frequencies. The absorption is optimized by tuning the geometry of the resonators, i.e., by tuning the viscothermal losses of each element. Experiments with the 1D array were performed in an impedance tube. The designed system is extended to 2D by periodically replicating the 1D array. The 2D system has been numerically modeled and experimentally tested in an anechoic chamber. It preserves the absorption properties of the 1D system and introduces efficient diffusion at higher frequencies due to the joint effect of resonances and multiple scattering inside the discrete 2D structure. The combined effect of sound absorption at low frequencies and sound diffusion at higher frequencies, may play a relevant role in the design of noise reduction systems for different applications.This research was funded by the European Space Agency under the Networking/Partnering Initiative (NPI) contract number 441-2015. In memoriam to Julián Santiago-Prowald, Senior Advisor for the Structures, Mechanisms and Materials Division of ESA, a great man that always gave us his tireless support. AC acknowledges financial support from Generalitat Valenciana through the grant APOSTD/2018/229. VRG acknowledges the financial support from RFI Le Mans Acoustique (Région Pays de la Loire) in the framework of the project HYPERMETA funded under the program Étoiles Montantes of the Région Pays de la Loire. Authors acknowledge the support of the European Space Agency under contract 441-2015 Co- Sponsored PhD ¿Acoustic Reduction Methods for the Launch Pad¿ and project TRP ESA AO/1-9479/18/NL/LvH ¿Launch Sound Level Reduction¿. This article is based upon work from COST Action DENORMS CA15125, supported by COST (European Cooperation in Science and Technology).Herrero-Durá, I.; Cebrecos, A.; Picó Vila, R.; Romero-García, V.; García-Raffi, LM.; Sánchez Morcillo, VJ. (2020). Sound absorption and diffusion by 2D arrays of Helmholtz resonators. Applied Sciences. 10(5):1-15. https://doi.org/10.3390/app10051690S115105Sigalas, M. M., & Economou, E. N. (1992). Elastic and acoustic wave band structure. Journal of Sound and Vibration, 158(2), 377-382. doi:10.1016/0022-460x(92)90059-7Matlack, K. H., Bauhofer, A., Krödel, S., Palermo, A., & Daraio, C. (2016). Composite 3D-printed metastructures for low-frequency and broadband vibration absorption. Proceedings of the National Academy of Sciences, 113(30), 8386-8390. doi:10.1073/pnas.1600171113Wormser, M., Wein, F., Stingl, M., & Körner, C. (2017). Design and Additive Manufacturing of 3D Phononic Band Gap Structures Based on Gradient Based Optimization. Materials, 10(10), 1125. doi:10.3390/ma10101125Lucklum, F., & Vellekoop, M. J. (2018). Bandgap engineering of three-dimensional phononic crystals in a simple cubic lattice. Applied Physics Letters, 113(20), 201902. doi:10.1063/1.5049663D’Alessandro, L., Ardito, R., Braghin, F., & Corigliano, A. (2019). Low frequency 3D ultra-wide vibration attenuation via elastic metamaterial. Scientific Reports, 9(1). doi:10.1038/s41598-019-44507-6Martínez-Sala, R., Sancho, J., Sánchez, J. V., Gómez, V., Llinares, J., & Meseguer, F. (1995). Sound attenuation by sculpture. Nature, 378(6554), 241-241. doi:10.1038/378241a0Cebrecos, A., Krattiger, D., Sánchez-Morcillo, V. J., Romero-García, V., & Hussein, M. I. (2019). The finite-element time-domain method for elastic band-structure calculations. Computer Physics Communications, 238, 77-87. doi:10.1016/j.cpc.2018.12.016Cebrecos, A., Romero-García, V., & Groby, J. (2019). Complex Dispersion Relation Recovery from 2D Periodic Resonant Systems of Finite Size. Applied Sciences, 9(3), 478. doi:10.3390/app9030478Hussein, M. I., Leamy, M. J., & Ruzzene, M. (2014). Dynamics of Phononic Materials and Structures: Historical Origins, Recent Progress, and Future Outlook. Applied Mechanics Reviews, 66(4). doi:10.1115/1.4026911Sanchez-Perez, J. V., Rubio, C., Martinez-Sala, R., Sanchez-Grandia, R., & Gomez, V. (2002). Acoustic barriers based on periodic arrays of scatterers. Applied Physics Letters, 81(27), 5240-5242. doi:10.1063/1.1533112Martínez-Sala, R., Rubio, C., García-Raffi, L. M., Sánchez-Pérez, J. V., Sánchez-Pérez, E. A., & Llinares, J. (2006). Control of noise by trees arranged like sonic crystals. Journal of Sound and Vibration, 291(1-2), 100-106. doi:10.1016/j.jsv.2005.05.030Garcia-Raffi, L. M., Salmerón-Contreras, L. J., Herrero-Durá, I., Picó, R., Redondo, J., Sánchez-Morcillo, V. J., … Romero-García, V. (2018). Broadband reduction of the specular reflections by using sonic crystals: A proof of concept for noise mitigation in aerospace applications. Aerospace Science and Technology, 73, 300-308. doi:10.1016/j.ast.2017.11.048Sanchez-Perez, J. V., Castineira-Ibanez, S., Romero-Garcia, V., & Garcia-Raffi, L. M. (2015). PERIODIC SYSTEMS AS ROAD TRAFFIC NOISE REDUCING DEVICES: PROTOTYPE AND STANDARDIZATION. Environmental Engineering and Management Journal, 14(12), 2759-2769. doi:10.30638/eemj.2015.293Kandula, M. (2009). Broadband shock noise reduction in turbulent jets by water injection. Applied Acoustics, 70(7), 1009-1014. doi:10.1016/j.apacoust.2008.12.001Liu, Z., Zhang, X., Mao, Y., Zhu, Y. Y., Yang, Z., Chan, C. T., & Sheng, P. (2000). Locally Resonant Sonic Materials. Science, 289(5485), 1734-1736. doi:10.1126/science.289.5485.1734Fang, N., Xi, D., Xu, J., Ambati, M., Srituravanich, W., Sun, C., & Zhang, X. (2006). Ultrasonic metamaterials with negative modulus. Nature Materials, 5(6), 452-456. doi:10.1038/nmat1644Sugimoto, N., & Horioka, T. (1995). Dispersion characteristics of sound waves in a tunnel with an array of Helmholtz resonators. The Journal of the Acoustical Society of America, 97(3), 1446-1459. doi:10.1121/1.412085Theocharis, G., Richoux, O., García, V. R., Merkel, A., & Tournat, V. (2014). Limits of slow sound propagation and transparency in lossy, locally resonant periodic structures. New Journal of Physics, 16(9), 093017. doi:10.1088/1367-2630/16/9/093017Jiménez, N., Cox, T. J., Romero-García, V., & Groby, J.-P. (2017). Metadiffusers: Deep-subwavelength sound diffusers. Scientific Reports, 7(1). doi:10.1038/s41598-017-05710-5Ballestero, E., Jiménez, N., Groby, J.-P., Dance, S., Aygun, H., & Romero-García, V. (2019). Experimental validation of deep-subwavelength diffusion by acoustic metadiffusers. Applied Physics Letters, 115(8), 081901. doi:10.1063/1.5114877Romero-García, V., Sánchez-Pérez, J. V., & Garcia-Raffi, L. M. (2011). Tunable wideband bandstop acoustic filter based on two-dimensional multiphysical phenomena periodic systems. Journal of Applied Physics, 110(1), 014904. doi:10.1063/1.3599886Lagarrigue, C., Groby, J. P., & Tournat, V. (2013). Sustainable sonic crystal made of resonating bamboo rods. The Journal of the Acoustical Society of America, 133(1), 247-254. doi:10.1121/1.4769783Krynkin, A., Umnova, O., Yung Boon Chong, A., Taherzadeh, S., & Attenborough, K. (2010). Predictions and measurements of sound transmission through a periodic array of elastic shells in air. The Journal of the Acoustical Society of America, 128(6), 3496-3506. doi:10.1121/1.3506342Koussa, F., Defrance, J., Jean, P., & Blanc-Benon, P. (2013). Acoustical Efficiency of a Sonic Crystal Assisted Noise Barrier. Acta Acustica united with Acustica, 99(3), 399-409. doi:10.3813/aaa.918621Castiñeira-Ibáñez, S., Romero-García, V., Sánchez-Pérez, J. V., & Garcia-Raffi, L. M. (2010). Overlapping of acoustic bandgaps using fractal geometries. EPL (Europhysics Letters), 92(2), 24007. doi:10.1209/0295-5075/92/24007García-Chocano, V. M., Cabrera, S., & Sánchez-Dehesa, J. (2012). Broadband sound absorption by lattices of microperforated cylindrical shells. Applied Physics Letters, 101(18), 184101. doi:10.1063/1.4764560Lardeau, A., Groby, J.-P., & Romero-García, V. (2016). Broadband Transmission Loss Using the Overlap of Resonances in 3D Sonic Crystals. Crystals, 6(5), 51. doi:10.3390/cryst6050051Cavalieri, T., Cebrecos, A., Groby, J.-P., Chaufour, C., & Romero-García, V. (2019). Three-dimensional multiresonant lossy sonic crystal for broadband acoustic attenuation: Application to train noise reduction. Applied Acoustics, 146, 1-8. doi:10.1016/j.apacoust.2018.10.020Dimitrijević, S. M., García-Chocano, V. M., Cervera, F., Roth, E., & Sánchez-Dehesa, J. (2019). Sound Insulation and Reflection Properties of Sonic Crystal Barrier Based on Micro-Perforated Cylinders. Materials, 12(17), 2806. doi:10.3390/ma12172806Stinson, M. R. (1991). The propagation of plane sound waves in narrow and wide circular tubes, and generalization to uniform tubes of arbitrary cross‐sectional shape. The Journal of the Acoustical Society of America, 89(2), 550-558. doi:10.1121/1.400379Duclos, A., Lafarge, D., & Pagneux, V. (2009). Transmission of acoustic waves through 2D phononic crystal: visco-thermal and multiple scattering effects. The European Physical Journal Applied Physics, 45(1), 11302. doi:10.1051/epjap:2008203Romero-García, V., Theocharis, G., Richoux, O., & Pagneux, V. (2016). Use of complex frequency plane to design broadband and sub-wavelength absorbers. The Journal of the Acoustical Society of America, 139(6), 3395-3403. doi:10.1121/1.4950708Romero-García, V., Theocharis, G., Richoux, O., Merkel, A., Tournat, V., & Pagneux, V. (2016). Perfect and broadband acoustic absorption by critically coupled sub-wavelength resonators. Scientific Reports, 6(1). doi:10.1038/srep19519Jiménez, N., Huang, W., Romero-García, V., Pagneux, V., & Groby, J.-P. (2016). Ultra-thin metamaterial for perfect and quasi-omnidirectional sound absorption. Applied Physics Letters, 109(12), 121902. doi:10.1063/1.4962328Jiménez, N., Romero-García, V., Pagneux, V., & Groby, J.-P. (2017). Quasiperfect absorption by subwavelength acoustic panels in transmission using accumulation of resonances due to slow sound. Physical Review B, 95(1). doi:10.1103/physrevb.95.014205Jiménez, N., Romero-García, V., Pagneux, V., & Groby, J.-P. (2017). Rainbow-trapping absorbers: Broadband, perfect and asymmetric sound absorption by subwavelength panels for transmission problems. Scientific Reports, 7(1). doi:10.1038/s41598-017-13706-4Merkel, A., Theocharis, G., Richoux, O., Romero-García, V., & Pagneux, V. (2015). Control of acoustic absorption in one-dimensional scattering by resonant scatterers. Applied Physics Letters, 107(24), 244102. doi:10.1063/1.4938121Kergomard, J., & Garcia, A. (1987). Simple discontinuities in acoustic waveguides at low frequencies: Critical analysis and formulae. Journal of Sound and Vibration, 114(3), 465-479. doi:10.1016/s0022-460x(87)80017-2Sánchez-Dehesa, J., Garcia-Chocano, V. M., Torrent, D., Cervera, F., Cabrera, S., & Simon, F. (2011). Noise control by sonic crystal barriers made of recycled materials. The Journal of the Acoustical Society of America, 129(3), 1173-1183. doi:10.1121/1.3531815Christensen, J., Romero-García, V., Picó, R., Cebrecos, A., de Abajo, F. J. G., Mortensen, N. A., … Sánchez-Morcillo, V. J. (2014). Extraordinary absorption of sound in porous lamella-crystals. Scientific Reports, 4(1). doi:10.1038/srep0467

Health-5G: A Mixed Reality-Based System for Remote Medical Assistance in Emergency Situations

Mixed reality is the combination of virtual and augmented reality to interactively and believably merge physical and computer-generated environments. This paper discusses the design of Health5G, a scalable mixed reality-based system that facilitates and supports emergency response by medical emergency teams. Health-5G is supported by a distributed architecture divided into four interrelated applications responsible for advanced computer-human interaction, effective real-time videoconference, medical device integration, and communication infrastructure, respectively. The mixed reality layer is provided by the headset Microsoft Hololens 2™. Health-5G is based on scenarios in which emergency personnel wear mixed reality glasses that can transmit audio, video, and data streams bidirectionally over a 5G network to medical specialists stationed in a hospital at any distance. Thanks to Health-5G, the specialist will be able to access the emergency team’s point of view at any time and provide verbal and visual instructions, including gestures and positioning of graphical markers in 3D space. In this way, emergency personnel can provide the best possible care to the patient without having to wait for them to arrive at the hospital, saving a lot of time in scenarios where every second can make a difference. Health-5G also addresses the integration of medical devices and the collection of the patient’s medical data in a scalable way through optical character recognition. A case study is discussed where Health-5G is used to attend a patient in the street suffering from syncope due to third-degree atrioventricular block. Latency and performance tests over a 5G network are also discussed. To the best of our knowledge, there is no comprehensive solution in the literature that provides all the capabilities offered by Health-5G in terms of functionality and advanced interaction mechanisms within the context of remote, immersive support in emergency situations