Browsing by Author "Lindh, Niko"
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Item Laser-patterned polymer film stacks for sound absorption(2024-08-29) Lindh, Niko; Jokinen, Ville; Kemian tekniikan korkeakoulu; Franssilla, SamiDevelopment of new and innovative acoustical materials has raised interest as the harmful effects of noise have become better understood. Many commonly used sound absorbing materials have flaws regarding their manufacturing or use and as such, more sustainable materials and methods are explored in hopes of replacing them. This thesis aims to show that laser ablation could be a potential chemical free method for fabricating sound absorbing structures. Polymer films were used as the basis of these structures as affordability, recyclability and varying physical proper-ties can extend the applicability and scalability of the obtained solutions. Acrylic glass samples (PMMA) were patterned with a laser micromachining tool and their sound absorption properties were measured using the impedance tube method. Large scale feasibility study was conducted with a sound pressure level measurement. The results show that stacks of these patterned films can absorb sound effectively and reduce the transmitted sound by even 30 dB in the frequency range of 2-5 kHz where the human ears are the most sensitive.Item Superparamagneettisten Fe3O4-nanopartikkelien synteesi ja sovellukset(2022-05-08) Lindh, Niko; Yliniemi, Kirsi; Kemiantekniikan korkeakoulu; Kontturi, Eero