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The Helmholtz resonance acoustic metamaterial is an effective sound absorber in the field of noise reduction, especially in the low-frequency domain. To overcome the conflict between the number of Helmholtz resonators and the volume of the rear cavity for each chamber with a given front area of single-layer metamaterial, a novel acoustic metamaterial of interlayer parallel connection of multiple Helmholtz resonators (IPC-MHR) is proposed in this study. The developed IPC-MHR consists of several layers, and the Helmholtz resonators among different layers are connected in parallel. The sound absorption property of IPC-MHR is studied by finite element simulation and further optimized by particle swarm optimization algorithm, and it is validated by standing wave tube measurement with the sample fabricated by additive manufacturing. The average sound absorption coefficient in the discrete frequency band [200 Hz, 300 Hz] U [400 Hz, 600 Hz] U [800 Hz, 1250 Hz] is 0.7769 for the IPC-MHR with four layers. Through the optimization of the thickness of each layer, the average sound absorption coefficient in 250-750 Hz is up to 0.8068. Similarly, the optimized IPC-MHR with six layers obtains an average sound absorption coefficient of 0.8454 in 300-950 Hz, which exhibits an excellent sound absorption performance in the low-frequency range with a wide band. The IPC-MHR can be used to suppress obnoxious noise in practical applications.
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http://dx.doi.org/10.3390/ma18030682 | DOI Listing |
ACS Omega
September 2025
Nanohybrids and Innovation Coating Research Group (NHIC), National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Khlong Luang, Pathumthani 12120, Thailand.
Using leaf fibers from pineapple (PALFs) as a model dual-purpose plant, we deliberately explore the effect of bio- and semibiobased treatment using xylanase, cellulase, and a mixture of pectinase and amylase. We assess these treatments for their potential to selectively and precisely remove lignocellulosic components. Additionally, we examine how they modify the relative content of cellulose, hemicellulose, and lignin, as these are key factors affecting the physical appearance, dimensional structures, and mechanical integrity.
View Article and Find Full Text PDFJ Acoust Soc Am
September 2025
The Marcus Wallenberg Laboratory for Sound and Vibration Research, Department of Engineering Mechanics, KTH Royal Institute of Technology, Teknikringen 8, 10044 Stockholm, Sweden.
This work presents a data-driven approach to estimating the sound absorption coefficient of an infinite porous slab using a neural network and a two-microphone measurement on a finite porous sample. A one-dimensional-convolutional network predicts the sound absorption coefficient from the complex-valued transfer function between the sound pressure measured at the two microphone positions. The network is trained and validated with numerical data generated by a boundary element model using the Delany-Bazley-Miki model, demonstrating accurate predictions for various numerical samples.
View Article and Find Full Text PDFInt J Biol Macromol
August 2025
National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215000, PR China; Wuhu Innovation New Materials Co., Ltd, Wuhu 241000, PR China. Electronic address:
As modern industry continues to advance, noise pollution is becoming increasingly severe, posing a significant threat to the global economy and human health. Given their porous structure and lightweight properties, aerogels exhibit substantial potential in the field of acoustics. Concurrently, the use of environmentally-friendly, biodegradable materials such as chitosan (CS) and polyvinyl alcohol (PVA) not only helps address environmental challenges but also contributes to reducing pollution.
View Article and Find Full Text PDFMaterials (Basel)
August 2025
Department of Mechanical Engineering, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, QC J1K 2R1, Canada.
This study investigates the use of a local fiber, specifically milkweed that grows in Quebec, Canada, for nonwoven building applications. Milkweed is a natural fiber with an ultra-lightweight hollow structure that provides excellent acoustic and thermal insulation properties. To provide three-dimensional stability to nonwovens, milkweed fibers were blended with a low-melt fiber composed of a polyethylene terephthalate core and a polyolefin sheath (LM 2.
View Article and Find Full Text PDFRev Sci Instrum
August 2025
Kavli Institute of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology, 2628CJ Delft, The Netherlands.
Superfluid helium is a prototypical quantum liquid. As such, it has been a prominent platform for the study of quantum many body physics. More recently, the outstanding mechanical and optical properties of superfluid helium, such as low mechanical dissipation and low optical absorption, have positioned superfluid helium as a promising material platform in applications ranging from dark matter and gravitational wave detection to quantum computation.
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