Annals Warsaw University of Life Sciences Forestry and Wood Technology No 107 Warsaw 2019 Contents: PAWEŁ KOZAKIEWICZ, ROBERT BRZOZOWSKI, AGNIESZKA LASKOWSKA, MARCIN ZBIEĆ „Acoustic insulation properties of selected African wood species: padouk, bubinga, sapele.” 4 PIOTR F. BOROWSKI „Bamboo as an innovative material for many branches of world industry.” 13 MARTA BABICKA, KRZYSZTOF DWIECKI, IZABELA RATAJCZAK „A comparison of methods for obtaining nanocellulose using acid and ionic liquid hydrolysis reactions.” 19 SŁAWOMIR KRZOSEK, IZABELA BURAWSKA-KUPNIEWSKA, PIOTR MAŃKOWSKI, MAREK GRZEŚKIEWICZ „Comparison results of visual and machine strength grading of Scots pine sawn timber from the Silesian Forestry Region in Poland.” 24 ZUZANA VIDHOLDOVÁ, DOMINIKA KORMÚTHOVÁ, JÁN IŽDINSKÝ, RASTISLAV LAGAŇA „Compressive resistance of the mycelium composite.” 31 1 KATARZYNA MYDLARZ „Corporate social responsibility in woodworking enterprises.” 37 BEATA FABISIAK, ANNA JANKOWSKA, ROBERT KŁOS „Dual study possibilities in selected EU countries.” 45 IZABELA BETLEJ, BOGUSŁAW ANDRES „Evaluation of fungicidal properties of post-cultured liquid medium from the Dual culture of Kombucha microorganisms against selected mold fungi.” 54 IGOR NOVÁK, JURAJ PAVLINEC, IVAN CHODÁ, ANGELA KLEINOVÁ, JOZEF PREŤO, VLADIMÍR VANKO „The grafting of metallocene copolymer to higher polarity with acrylic acid.” 60 JOANNA WACHOWICZ, KLAUDIA WIERZBICKA, PAWEŁ CZARNIAK, JACEK WILKOWSKI „The influence of WC grain size on the durability of WCCo cutting edges in the machining of wood-based materials.” 65 MAREK WIERUSZEWSKI, RADOSŁAW MIRSKI, ADRIAN TROCIŃSKI, JAKUB KAWALERCZYK „Influence of qualitative and dimensional classification of Pinewood raw material as an efficiency indicator in the production of selected timber assortments.” 72 SZYMON NIECIĄG, TOMASZ ROGOZIŃSKI, JACEK WILKOWSKI, BARTOSZ PAŁUBICKI „Timber cross-cutting accuracy obtained with an automatic saw.” 80 MARTA DWORNIK, ANNA ROZANSKA, PIOTR BEER „Traditional ornaments of Świdermajers’ style windows in the town of Otwock.” 84 DARIA BRĘCZEWSKA-KULESZA, GRZEGORZ WIELOCH „Use of wood in the Baltic courses architecture on the example of Binz in Ruges.” 104 JOZEF KÚDELA „Wood fibreboard paraffin hydrophobization and the impact of this treatment on the board surface finishing quality.” 115 MAREK WIERUSZEWSKI, RADOSŁAW MIRSKI, ADRIAN TROCIŃSKI „Raw material factors affecting the quota of structural wood in sawmill production.” 124 DONATA KRUTUL, ANDRZEJ ANTCZAK, ANDRZEJ RADOMSKI, MICHAŁ DROŻDŻEK, TERESA KŁOSIŃSKA, JANUSZ ZAWADZKI „The chemical composition of poplar wood in relation to the species and the age of trees.”131 EWA DOBROWOLSKA, DANIEL KUPIEC, ZBIGNIEW KARWAT „Testing the tightness of a square joint between oak wood elements.” 139 ADAM KRAJEWSKI, PIOTR WITOMSKI, ANNA OLEKSIEWICZ „The borings of Teredinidae in fossil wood of Taxodium Distichum Gothan, 1906.” 149 2 Scientific council: Miroslav Rousek (Czech Republic) Ján Sedliačik (Slovakia) Nencho Deliiski (Bulgaria) Ladislav Dzurenda (Slovakia) Olena Pinchewska (Ukraine) Włodzimierz Prądzyński (Poland) Loredana Badescu (Romania) Kazimierz Orłowski (Poland) Iskandar Alimov (Uzbekistan) Board of reviewers: Bogusław Andres Teresa Kłosińska Andrzej Antczak Grzegorz Kowaluk Bogusław Andres Paweł Kozakiewicz Piotr Beer Adam Krajewski Izabela Betlej Krzysztof Krajewski Justyna Biernacka Sławomir Krzosek Piotr Boruszewski Agnieszka Laskowska Piotr Borysiuk Mariusz Mamiński Izabela Burawska-Kupniewska Mateusz Niedbała Ewa Dobrowolska Piotr Przybysz Michał Drożdżek Anna Różańska Jarosław Górski Jacek Wilkowski Emila Grzegorzewska Piotr Witomski Agnieszka Jankowska Marcin Zbieć Errata: The authors of the article: Broda M., Mazela B., Królikowska-Pataraja K., Siuda J. (2015): The state of degradation of waterlogged wood from different environments. Annals of Warsaw University of Life Sciences - SGGW, Forestry and Wood Technology 91, pp. 23-27, explain, that: - at Table 1 a citation of the publication: Zborowska M., Królikowska-Pataraja K., Waliszewska B., Tekień P., Gajewska J., Kisiel I (2012): Condition of preservation and causes of degradation of bridge remains recovered from the bottom of Gągnowskie lake. Physico-chemical analysis of lignocellulosic materials. Part II (ed. by J. Zawadzki, B. Waliszewska) WULS-SGGW Press, Warszawa 2012, pp. 64-73 is missing, - at Table 2 a citation of the publication: Zborowska M., Królikowska-Pataraja K., Waliszewska B., Tekień P., Gajewska J., Kisiel I (2012): Condition of preservation and causes of degradation of bridge remains recovered from the bottom of Gągnowskie lake. Physico-chemical analysis of lignocellulosic materials. Part II (ed. by J. Zawadzki, B. Waliszewska) WULS-SGGW Press, Warszawa 2012, pp. 64-73 is missing. The missing citations were not a result of an intentional act of the authors but of an unfortunate oversight, and the present errata intends to remedy this omission. Warsaw University of Life Sciences Press e-mail:[email protected] SERIES EDITOR Ewa Dobrowolska ISSN 1898-5912 Anna Sekrecka-Belniak Mateusz Niedbała Drukarnia POZKAL Spółka z o.o. Spółka komandytowa 88-100 Inowrocław, ul. Cegielna 10 – 12 3 Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 4-12 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019) Acoustic insulation properties of selected African wood species: padouk, bubinga, sapele PAWEŁ KOZAKIEWICZ1, ROBERT BRZOZOWSKI1, AGNIESZKA LASKOWSKA 1, MARCIN ZBIEĆ2 1Department of Wood Science and Wood Preservation; 2Department of Technology and Entrepreneurship in Wood Industry, Faculty of Wood Technology, Warsaw University of Life Sciences - SGGW, 166 Nowoursynowska St., 02 - 787 Warsaw Abstract: Acoustic insulation properties of selected African wood species: padouk, bubinga, sapele. The work determines the sound insulation properties of three wood species used in various types of acoustic partitions. The tests were carried out in a small acoustic chamber after generating white acoustic noise for 5.5 s. The level of sound intensity generated by the loudspeaker was 110 dB. The thickness of the wooden partitions was 20, 10 or 5 mm. The study was preceded by the determination of the moisture content, density and dynamic modulus of elasticity of the tested wood samples. In the 20–600 Hz frequency range, the sound insulation characteristics of the tested partitions changed dynamically but very similarly, while maintaining the mass law. In the higher frequency range, the impact of the partition thickness on insulation was individual, different for each wood species. Keywords: African wood, acoustic insulation, density, dynamic modulus of elasticity, small acoustic chamber INTRODUCTION Acoustic properties of wood determine its use, among other things, for the production of sound absorbing materials. With the application of wood in various types of partitions, e.g. wall elements (facades, cladding, panelling) and flooring, the sound insulation is taken into account [Kozakiewicz et al. 2012]. Isolation, i.e. attenuation, is the ability to weaken the intensity (silencing) of sounds passing through the material, expressed in decibels. Waves with higher frequencies (high tones) are much easier to suppress than those with low frequencies. The acoustic properties of wood are significantly affected by its density and modulus of elasticity. In a simplified manner, with increasing wood density, the acoustic insulation is also increasing [Kollmann and Côte 1968, Krzysik 1978, Bucur 2006, Kozakiewicz 2012]. However, due to the diversity of wood structure and the complexity of sound phenomena, including a number of accompanying effects (e.g. reflection, deflection and penetration) [Kirpluk 2014], it is always desirable to experimentally verify its sound insulation properties. Insulation is also proportional to the increase in the mass of a partition and the sound frequency [Bucur 2006]. African species of wood have long been present on the European market and they find various applications, also resulting from specific features and properties. High natural durability of many African species, defined in EN 350:2016, and their high density transforming into high strength parameters predestine them for external applications [Kozakiewicz et al. 2010], such as sound absorbing and anti-glare screens in communication arteries. The African wood species are also the material used for solid and layered flooring materials – as horizontal partitions of buildings [Kozakiewicz et al. 2012]. The aim of the study was to determine the sound insulation properties of three African wood species – padouk, bubinga and sapele – popular on the European market. 4 MATERIAL AND METHOD Samples of selected African wood species (padouk, bubinga, sapele) were used in the study. The tested wood species are used as various types of acoustic barriers in buildings, as well as in acoustic screens [Kozakiewicz 2007, Kozakiewicz et al. 2010]. Selected information on the tested wood species was compiled in Table 1. To determine the sound insulation properties, samples with planed surfaces of 500 mm (longitudinal) x 300 mm (tangential) and the final thickness of 20 mm (radial) were used – samples with a dominant tangential section were selected. After the initial determination of the insulation parameters, the samples were planed down to a thickness of 10 mm, and then to 5 mm; and the acoustic chamber test was repeated for each thickness. Table 1. The basic information about investigated wood species from