WOOD RESEARCH Volume 70, Number 4, 2025
DOAN VAN DUONG and MASUMI HASEGAWA

NONDESTRUCTIVE PREDICTION OF BENDING STRENGTH OF PINUS MASSONIANA LAMB. LOGS AND SMALL CLEAR SPECIMENS USING STRESS-WAVE MEASUREMENTS

The main objective of this study was to investigate the relationships between stress-wave velocity measured in logs and small clear specimens and the bending strength of Pinus massoniana trees planted in northern Vietnam. Stress-wave velocity (SWVL) and green wood density (WDL) were measured on logs collected from different heightlevels of 23-year-olds P. massonianatrees. Stress-wave velocity (SWVS), wood density (WDS), and bending strength (MOR) were subsequently determined on small clear specimens prepared from the logs. Regression analyses revealed significant correlations between SWVL and MOR (r = 0.73, P < 0.001) and between SWVS and MOR (r = 0.80, P < 0.001). These results show that stress-wave velocity measurements, whether taken on logs or small specimens, are effective for segregating P. massoniana lumber resources based on MOR. A more accurate prediction of strength was obtained when stress-wave velocity and log or specimen wood density were used together to calculate the dynamic modulus of elasticity of logs (DMOEL) or specimens (DMOES), respectively. The correlation coefficients were 0.82 (P < 0.001) between DMOEL and MOR, and 0.93 (P < 0.001) between DMOES and MOR.

WOOD RESEARCH Volume 61, Number 6, 2016
Xu Jiahe, Zhou Yucheng, Qi Yuhan, Hou Xiaopeng, Ge Zhedong, and Chen Yongping

A weighted filtered back projection algorithm for log CT two-dimensional and three-dimensional image reconstruction

Log computer tomography (CT) image reconstruction is the kernel of wood CT nondestructive testing (NDT) technology. In this paper, based on the logs physical properties and the X-rays propagation characteristics in solid, the X-ray wave equation inside logs is deduced. A weighted filtered back projection (FBP) algorithm for log CT image reconstruction is proposed. Four group of logs are chosen for simulations on the weighted FBP algorithm. In the twodimensional image reconstruction process, the capabilities between conventional FBP algorithm and weighted FBP algorithm are compared to verify the effectiveness of the algorithms for logs of different species. From both the image quality and data results, it can be clearly seen that the weighted FBP algorithm has good performance and advantages for image reconstruction process of log CT scan. The three-dimensional log image reconstruction is well completed, but has a big room for improvement.