WOOD RESEARCH Volume 68, Number 3, 2023
Yoshikazu Mori, Mio Nakajima, Akihiro Ishida, Noboru Ito, Yohei Kurata, Kazumasa Shimizu, Yoshihiro Katayama, Makoto Kiguchi, Kana Yamashita, Takeshi Fujiwara, and Mario Tonosaki

Changes in Hemicellulose Structure Associated with the Transition from Earlywood to Latewood at Juvenile Wood in Cryptomeria Japonica

The chemical composition and variations in chemical structure of hemicellulose in earlywood (EW) and latewood (LW) of two individual Japanese cedar trees (C-Boka and T-Boka) were investigated. The trees were cultivated under different growth conditions: C-Boka grew slowly in a forest, while T-Boka grew rapidly in a location rich in nutrients and sunshine. For the chemical structure of hemicellulose, arabinoglucuronoxylan (AGX) showed varied side-chain substitution rates with glucuronic acid and different molecular weights in the transition between EW and LW. In contrast, the fundamental composition of glucomannan/galactoglucomannan (GM/GGM) was relatively unchanged between EW and LW. The modification of AGX and GM/GGM from EW to LW differed between C-Boka and T-Boka and might be influenced by the growth rate of the trees.

WOOD RESEARCH Volume 65, Number 1, 2020
Zehui Ju, Qian He, Tianyi Zhan, Haiyang Zhang, Lu Hong, and Xiaoning Lu

Calculation of sound insulation of softwood samples at normal incidence and comparison with experimental data

The acoustic simulations were carried out for softwood and composites in order to evaluate their sound properties. Theoretical value of sound insulation was predicted by regarding the substances in the wood cell wall as equivalence to specific medium based on Biot model, and the wood microscopic characteristics, such as the length and diameter of tracheid, diameter of pit, and porosity, were taken into account for determining the equivalent density and bulk modulus of wood. By comparing the tested and predicted values of sound insulation, the conclusions were drawn as follows: the predicted values of sound insulation were significantly correlated with the tested values for wood and wood composites. As for Masson pine, the adjacent of earlywood and latewood was considered as sandwich structure for the calculation of sound insulation. The transfer function involved in sound insulation simulation provided an effective method to characterize the sound insulation volume of wood and wood composite in construction and decoration areas.