Article
Materials Science, Paper & Wood
Mikko J. Valkonen, Jose Cucharero, Tapio Lokki, Lauri Rautkari, Tuomas Hanninen
Summary: In this study, bio-based sound absorbers were prepared from waste wood and other cellulosic materials. The mechanical stability of the fully bio-based sound absorbers was influenced by the content of cutter shavings (CSs). The sound absorption properties could be tuned by adjusting the CSs and fiber contents.
Article
Physics, Applied
Yukun Zhou, Xueyong Zhang, Ying Wang, Yan Feng
Summary: The study introduces a low-frequency dual-band perfect acoustic absorption metaporous material, constructed by introducing Helmholtz resonance and Fabry-Perot resonance, achieving high-efficiency broadband acoustic absorption and showing potential for reducing low-frequency noise.
APPLIED PHYSICS EXPRESS
(2021)
Article
Physics, Applied
M. Mallejac, P. Sheng, V Tournat, V Romero-Garcia, J-P Groby
Summary: In this paper, a passive treatment method that considers the time domain and multiple reflections is proposed. A delay line is designed using slow-sound propagation in periodic structures, allowing the reproduction of sound perception over a larger distance. The limitations of real-time pulse propagation, dispersion, and losses on audio fidelity are also discussed.
PHYSICAL REVIEW APPLIED
(2022)
Article
Chemistry, Multidisciplinary
Tijana Todorovic, Emelie Norstrom, Farideh Khabbaz, Jorg Brucher, Eva Malmstrom, Linda Fogelstrom
Summary: This study explores the utilization of hemicelluloses, a byproduct from pulping, as a bio-based and harmless substitute for wood adhesives. It demonstrates that combining hemicelluloses with chitosan can achieve excellent bonding performance and water resistance, providing a sustainable alternative to fossil-based materials in the quest for a more environmentally friendly society.
Article
Nanoscience & Nanotechnology
Ju-Qi Ruan, Zhaoxi Li, Kai-Yue Xie, Wei Guo, Chunlong Fei, Ming-Hui Lu, Hai Yang
Summary: Wood is a sustainable material that has potential for sound absorption due to its porous characteristics. However, the low permeability of wood structures limits its acoustic absorption performance. In this study, a new type of cellulose wood (CW) was prepared through a two-step delignification process and supercritical CO2 drying. The CW exhibited high air permeability and superior porous characteristics compared to natural basswood, resulting in significant improvement in acoustic absorption performance. The CW also demonstrated high specific stiffness and diffuse reflectance across visible light.
Article
Mechanics
Tianyue Yuan, Xiang Song, Jingjian Xu, Baorui Pan, Dan Sui, Heye Xiao, Jie Zhou
Summary: This study designs a tunable acoustic composite metasurface with significant advantages in sound absorption performance. The phase gradient adjustment and resonance dissipation contribute to its excellent sound absorption ability. The modified microperforated panel system and the coiling-up space cavity enable the metasurface to achieve excellent sound absorption in both low and high frequency ranges.
COMPOSITE STRUCTURES
(2022)
Review
Polymer Science
Estelle Doineau, Bernard Cathala, Jean-Charles Benezet, Julien Bras, Nicolas Le Moigne
Summary: This review focuses on the development of hierarchical fibers by depositing nano-objects on their surface to tailor the fiber/matrix interface in (bio)composites, highlighting the potential of hierarchical fibers in enhancing structural performance of sustainable biocomposite materials. The study emphasizes that nano-objects coated on natural fibers can improve load transfer and interfacial adhesion, resulting in enhanced mechanical performance of biocomposites.
Article
Construction & Building Technology
Harinei Srinivasan, Hariharan Arumugam, Anto Dilip, Balaji Krishnasamy, M. I. Abdul Aleem, Arun Murugesan, Alagar Muthukaruppan
Summary: In this study, hybrid bio-composites were developed using epoxy resins and desert cotton and areca nut husk fibers for thermal, electrical, and acoustic insulation panel applications. The results showed that the composite panels had good thermal resistance, electrical volume resistivity, and sound absorption coefficient.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Yifan Zhu, Aurelien Merkel, Krupali Donda, Shiwang Fan, Liyun Cao, Badreddine Assouar
Summary: The study introduces the concept of a nonlocal acoustic metasurface absorber using a bridge structure to improve performance, achieving ultrabroadband sound absorption with deep-wavelength thickness. The nonlocality introduces three specific effects, optimizing effective acoustic impedances, shifting Fabry-Perot resonant frequencies, and enhancing coupling effects between adjacent unit cells, contributing to improved bandwidth and efficiency.
Article
Acoustics
Antonella Bevilacqua, Gino Iannace
Summary: This paper discusses the acoustic analysis of three specific scenarios in the context of the Roman theatre of Pompeii. It focuses on the reconstruction of the original form, a future acoustic shell design, and a modern style velarium design. The calibrated digital model shows that the main acoustic parameters are within optimal values, resulting in significant improvement in the acoustic performance of the space.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Forestry
Arne A. P. Imken, Burkhard Plinke, Carsten Mai
Summary: This study investigates the availability of hardwood fibres in the WFIB industry, finding that hardwood fibres contain more dust and are shorter, limiting their applicability for WFIB production. Two analytical approaches were chosen: blending hardwood fibres with supporting softwood fibres, and mathematical fractionation of hardwood fibres based on fibre length. It was concluded that blending hardwood fibres with at least 50% softwood fibres offers a promising approach for further study.
EUROPEAN JOURNAL OF WOOD AND WOOD PRODUCTS
(2021)
Article
Plant Sciences
Pedro E. G. Loureiro, Sonia M. S. Cadete, Radina Tokin, Dmitry V. Evtuguin, Henrik Lund, Katja S. Johansen
Summary: Enzymatic processes offer energy-efficient and reagent-saving alternatives to traditional chemical routes in the production of dissolving pulp for regenerated cellulosic fibres. Enzymes can control the purity and molecular weight of dissolving pulp, with endoglucanases effectively reducing cellulose molecular weight and increasing reactivity for viscose production. Additionally, lytic polysaccharide monooxygenases synergistically modify bleached dissolving pulp along with endoglucanases, showing promising results for pulp quality improvement.
FRONTIERS IN PLANT SCIENCE
(2021)
Article
Materials Science, Textiles
Yusuf Saygili, Garip Genc, Kenan Y. Sanliturk, Hasan Koruk
Summary: This study investigates the acoustic and mechanical properties of homogeneous and hybrid jute and luffa biocomposites. By designing and manufacturing composite materials, the elasticity moduli are determined using experimental and theoretical models. The results show that the hybrid composites have good acoustic absorption and damping properties.
JOURNAL OF NATURAL FIBERS
(2022)
Article
Materials Science, Textiles
Vikas Kumar Singh, Samrat Mukhopadhyay
Summary: This article studies the acoustic properties of fibrous structures made of banana fibers. The impedance tube method is used to test the acoustic barrier properties. The research attempts to counter low-frequency noise and enhance the transmission loss characteristics of these structures. The effect of different parameters and arrangement of structures on sound absorption and insulation is reported. A unique structure with varying compactness throughout its thickness is developed, and it is found that the areal density of samples, compactness of structure, and arrangement of structures can be adjusted to customize its sound barrier and absorption behavior. The structure developed in this research shows a maximum noise reduction coefficient of 0.78 and a transmission loss of up to 23 dB, which is comparable or better than other acoustic materials reported in literature and commercial products.
JOURNAL OF INDUSTRIAL TEXTILES
(2022)
Article
Acoustics
Youssef Cherradi, Ioan Calin Rosca, Camelia Cerbu, Hocine Kebir, Amine Guendouz, Mustafa Benyoucef
Summary: Novel sound insulation biocomposite materials using treated alfa fibers and sawdust wood fibers show great potential for sound absorption applications, with maximum sound absorption coefficient values of 0.98 at specific frequencies. The thickness of air gaps and additional woven flax shell layer have significant effects on low frequencies. The results indicate that these biocomposites could be an alternative to conventional materials for sound absorbing panels.
Correction
Acoustics
Antti Kuusinen, Tapio Lokki
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Acoustics
Nils Meyer-Kahlen, Sebastian J. Schlecht, Tapio Lokki
Summary: This study examines the accuracy of listener position dependent rendering in virtual reality room acoustics simulation and finds that a mismatch between the acoustics and visual representation may not affect the experience under certain conditions.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Review
Materials Science, Multidisciplinary
Tatiana Budtova, Tapio Lokki, Sadeq Malakooti, Ameya Rege, Hongbing Lu, Barbara Milow, Jaana Vapaavuori, Stephanie L. Vivod
Summary: Noise reduction is still an important priority in modern society, especially in urban areas and highly populated cities. Various porous materials, including aerogels, are commonly used for sound mitigating applications. However, the understanding of the acoustic properties of aerogels is incomplete and scattered, despite their complex three-dimensional architecture and other desirable properties.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Paper & Wood
Antti Koistinen, Josphat Phiri, Kavindra Kumar Kesari, Tapani Vuorinen, Thaddeus Maloney
Summary: This study investigates the impact of pulp prehydrolysis conditions on pulp structure, dissolution in a cold NaOH/ZnO solvent, and properties of regenerated cellulose films. The results show that hydrolysis significantly improves the dissolution of pulp and affects the swelling and pore structure of the resulting films. Surprisingly, higher hydrolysis temperature does not lead to increased fiber hornification, and low temperature hydrolysis results in more porous films after drying.
Article
Materials Science, Paper & Wood
Mikko J. Valkonen, Jose Cucharero, Tapio Lokki, Lauri Rautkari, Tuomas Hanninen
Summary: In this study, bio-based sound absorbers were prepared from waste wood and other cellulosic materials. The mechanical stability of the fully bio-based sound absorbers was influenced by the content of cutter shavings (CSs). The sound absorption properties could be tuned by adjusting the CSs and fiber contents.
Article
Engineering, Environmental
Fangxin Zou, Jose Cucharero, Yujiao Dong, Pinja Kangas, Ya Zhu, Janne Kaskirinne, Girish C. Tewari, Tuomas Hanninen, Tapio Lokki, Hailong Li, Jaana Vapaavuori
Summary: Effective use of sound absorption materials is crucial in reducing noise pollution. However, current porous sound absorption materials pose environmental pollution and potential health risks. In this study, we present a simple method to create eco-friendly and non-toxic pectin-based cryogels with hierarchically porous anisotropic structure. These cryogels demonstrate superior sound absorption performance, higher compression modulus, and comparable thermal conductivity. The sound absorption performance can be further enhanced by manipulating the pore wall density and size of small pores. This innovative strategy opens up opportunities for designing highly efficient bio-based noise absorption materials.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
A. S. Santos, E. S. Zamani, A. P. M. Sousa, P. C. O. R. Pinto, P. J. T. Ferreira, T. Maloney
Summary: This study aims to investigate the structure and performance of an air-laid sheet made of defibrated Eucalyptus pulp and polylactic acid (PLA) fibers. Different methodologies were used to prepare Eucalyptus pulp dry fibers, resulting in fibers with distinct morphological properties. Sheets with a grammage of 100 g m(-2) were prepared using a specially designed air-laid former, and their structural, mechanical, and water sorption properties were characterized. The results showed that sheets made from Eucalyptus fibers with fewer fines and fiber deformations had better absorbency, while those with more fines had higher strength. Sheets with 30% PLA fiber content exhibited the best combination of strength, absorption capacity, and stretch at break. The presence of PLA had a strong interaction with the fines in the sheet, affecting its consolidation and performance.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Multidisciplinary Sciences
Alvaro Vaz, Joao Coelho, Vera Costa, Thaddeus Maloney, Josphat Phiri, Paula Pinto, Antonio Mendes de Sousa, Rogerio Simoes
Summary: Hardwood vessel elements in wood-free printing paper operation can cause vessel picking and ink refusal, which can be mitigated with mechanical refining but at the cost of paper quality. Enzymatic passivation of vessels through xylanase and cellulase-laccase cocktail treatments improved paper quality by altering vessel adhesion and hydrophobicity. Thermoporosimetry analysis revealed more porous vessel structures, surface analysis showed lower O/C ratio, and bulk chemistry analysis indicated higher hemicellulose content. The enzymatic treatments decreased vessel picking count and reduced water contact angle of fiber sheets compared to vessel-rich sheets.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Analytical
Josphat Phiri, Hamidreza Ahadian, Maria Sandberg, Karin Granstrom, Thad Maloney
Summary: Two different methods of sample preparation, physical mixing and wet impregnation, were compared for synthesizing activated carbon from pine wood. The influence of these methods on the physicochemical properties of activated carbons was examined, and the results showed that wet impregnation resulted in higher capacitance at low current densities, but physical mixing led to more stable samples after 5000 cycles.
Article
Biochemistry & Molecular Biology
Tuukka Leva, Ville Rissanen, Lauri Nikkanen, Vilja Siitonen, Maria Heilala, Josphat Phiri, Thaddeus C. Maloney, Sergey Kosourov, Yagut Allahverdiyeva, Mikko Makela, Tekla Tammelin
Summary: To develop efficient solid-state photosynthetic cell factories for sustainable chemical production, we presented an interdisciplinary experimental toolbox to investigate and interlink the structure, operative stability, and gas transfer properties of alginate- and nanocellulose-based hydrogel matrices with entrapped cyanobacteria. The results showed that nanocellulose matrices have higher yield properties and alginate matrices possess higher rest properties due to their Ca2+-crosslinking. Additionally, porosity and rigidity of the matrices were found to be connected to their gas exchange rates over time.
Article
Materials Science, Paper & Wood
Deepika Dahiya, Sara Ceccherini, Thad C. Maloney
Summary: The aim of this study is to investigate the hornification process of enzymatically hydrolyzed high consistency softwood kraft pulp in an experimental defibration dryer. The dryer, operating under turbulent conditions, dries the pulp and prevents interfiber bonding, thus producing separated fiber population. The study reveals that the endoglucanase cocktail increases the pore volumes of micro-, meso-, and macropores during hydrolysis, while drying reduces the pore volumes, most significantly in the macropore region. After drying, less fibrillated pulp exhibits good fiber separation, whereas highly fibrillated samples form sub-millimeter, spherical particles.
Article
Agricultural Engineering
Ricardo O. Almeida, Thaddeus C. Maloney, Jose A. F. Gamelas
Summary: Nanocelluloses have attracted increasing attention due to their appealing intrinsic properties, but the economic and environmental problems associated with conventional production methods hinder large-scale production. Deep eutectic solvents (DESs) present a promising alternative in the production of nanocelluloses, offering biodegradability, biocompatibility, low toxicity, easy preparation, tunability, and recyclability. This article provides an overview of the production of (ligno)cellulose nanofibrils ((L)CNFs) and (ligno)cellulose nanocrystals ((L)CNCs) using DESs, as well as their applications. The use of different DES components allows for surface chemical functionalization of (L)CNFs, resulting in distinct material properties, and DES-(L)CNFs exhibit good mechanical properties in film form. DES-(L)CNCs can be produced with higher yields and better thermal stability compared to conventional methods. However, a comprehensive economic analysis is still lacking. Nevertheless, the recyclability and reuse of DESs make them promising candidates for large-scale production of nanocellulose (and nanocellulose-based films).
INDUSTRIAL CROPS AND PRODUCTS
(2023)
Article
Acoustics
Julie Meyer, Henna Tahvanainen, Jukka Saarelma, Tapio Lokki
Summary: The seat-dip effect refers to the phenomenon of low-frequency sounds propagating through the seating area of a performance space. This study quantifies the contribution of different geometric properties related to the seating area by simulating a large number of seat configurations. The results show that the step size and the opening underneath the seats are significant factors contributing to the seat-dip effect.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Acoustics
Winfried Lachenmayr, Nils Meyer-Kahlen, Otavio Colella Gomes, Antti Kuusinen, Tapio Lokki
Summary: This study examines the room acoustics of seven chamber music halls of different architectural styles through objective acoustic measurements and subjective listening experiments. The results show that the acoustic characteristics of the halls are not related to their shape, but rather depend on the distribution of early and late sound energy.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Acoustics
Panu Somervuo, Patrik Lauha, Tapio Lokki
Summary: The study explores the impact of landscape and distance on automatic species identification in birds and demonstrates that considering these factors can enhance the accuracy of identification. A method is proposed that uses impulse responses to modify existing bird sound recordings, which are measured in real environments. The method is demonstrated in different landscapes and distances, showing significant improvements in classification accuracy. The approach is not limited to bird sounds and can be applied to other animal and non-animal vocalizations.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
