Acoustic metamaterials are increasingly being considered as a viable technology for sound insulation. Fractal patterns constitute a potentially groundbreaking architecture for acoustic metamaterials. We describe in this work the behaviour of the transmission loss of Hilbert fractal metamaterials used for sound control purposes. The transmission loss of 3D printed metamaterials with Hilbert fractal patterns related to configurations from the zeroth to the fourth order is investigated here using impedance tube tests and Finite Element models. We evaluate, in particular, the impact of the equivalent porosity and the relative size of the cavity of the fractal pattern versus the overall dimensions of the metamaterial unit. We also provide an analytical formulation that relates the acoustic cavity resonances in the fractal patterns and the frequencies associated with the maxima of the transmission losses, providing opportunities to tune the sound insulation properties through control of the fractal architecture.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10625595 | PMC |
http://dx.doi.org/10.1038/s41598-023-43646-1 | DOI Listing |
J Acoust Soc Am
January 2025
Leibniz University Hannover, Institute of Structural Analysis, Appelstrasse 9a, 30167 Hannover, Germany.
Pile driving for offshore wind turbines typically generates high sound levels in the water column. Bubble curtains are frequently employed to protect marine fauna. This study aims to investigate the effect of a bubble curtain on the generated sound wave field.
View Article and Find Full Text PDFSci Rep
January 2025
Depto de Química, Universidade Federal de Minas Gerais, Belo Horizonte, MG, CEP 31.270-901, Brazil.
Magnetoliposomes containing magnetite, soy lecithin, stigmasterol, and beta-sitosterol of the mean size minor than 160 nm were obtained by a scalable and green process using autoclave and sonication without organic solvents. The formation, size of the liposome, linkage, and encapsulation of the magnetite were evaluated by Cryo-TEM. The stability of magnetoliposomes after storage for 6 months at 4 °C was improved by liposome size, the ability of soy lecithin to preserve the magnetite phase against oxidation, pH, polydispersity index, and zeta potential.
View Article and Find Full Text PDFIn Vitro Cell Dev Biol Anim
January 2025
Aquatic Animal Health Laboratory, PG & Research Department of Zoology, C. Abdul Hakeem College, (Affiliated to Thiruvalluvar University), Melvisharam, Tamil Nadu, India.
Tilapia parvovirus (TiPV) is an emerging viral pathogen and responsible for severe economic loss in tilapia culture production. Lethargic, cutaneous haemorrhages; ocular lesions; discolouration of gill and cloudy eye and exophthalmia are common symptoms of TiPV. The TiPV-suspected tilapia fish were collected from grow-out ponds situated in different parts of Tamil Nadu, India, and screened for TiPV by PCR.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China. Electronic address:
Thermochromic smart windows have been widely developed for building energy saving. However, most smart windows suffer from limited energy-saving performance, fixed phase transition temperature, and are not suitable for the temperature regulation needs of different application scenarios. Herein, a unique self-adaptive thermochromic hydrogel (HBPEC-PNA) with self-moisture-absorbing performance is reported that assembles solar energy cooling and evaporative heat dissipation.
View Article and Find Full Text PDFVision Res
January 2025
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Elevated intraocular pressure (IOP) is a significant risk factor for glaucoma, causing structural and functional damage to the eye. Increased IOP compromises the metabolic and structural integrity of retinal ganglion cell (RGC) axons, leading to progressive degeneration and influencing the ocular immune response. This study investigated early cellular and molecular changes in the retina and optic nerve (ON) following ocular hypertension (OHT).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!