Influence of hygrothermal condition on dynamic viscoelasticity of Chinese fir (Cunninghamia lanceolata). Part 2: moisture desorption

Holzforschung ◽  
2018 ◽  
Vol 72 (7) ◽  
pp. 579-588 ◽  
Author(s):  
Tianyi Zhan ◽  
Jiali Jiang ◽  
Jianxiong Lu ◽  
Yaoli Zhang ◽  
Jianmin Chang
Keyword(s):  
Cell Wall ◽  
Loss Modulus ◽  
Adsorbed Water ◽  
Chinese Fir ◽  
Cunninghamia Lanceolata ◽  
Dynamic Viscoelasticity ◽  
Heating Effects ◽  
Plateau Area ◽  
Set Up ◽  
Moisture Desorption

AbstractThe influence of hygrothermal condition on dynamic viscoelasticity of Chinese fir (Cunninghamia lanceolata) during the moisture desorption (MDes) process was investigated. The ambient hygrothermal environments were set up as a series of constant temperatures and two relative humidity (RH) modes (RHramp-downand RHisohume). The MDesprovided space for the rearrangement of the hydrogen bonds (Re-HB) and caused a mechano-sorptive (MS) effect. The enhancement of the Re-HB effect negatively correlated with the increment of loss modulus, while the elevation of the MS and the heating effects intensified the loss modulus. Lower values of RHc, determining the plateau area of loss modulus, were obtained at higher temperatures or greater RH ramping rates. The residual instability in the wood cell wall was quantitatively characterized by the extent of the MS effect. Residual instability was inversely proportional to the RHisohumelevel during the MDesprocess. The study of time dependent viscoelastic properties under moisture changing process provided insight into the condition of adsorbed water in the cell wall and optimized the manufacturing technique involved in the thermo-hygro-mechanical treatment of wood.

Dynamic viscoelastic properties of Chinese fir (Cunninghamia lanceolata) during moisture desorption processes

Holzforschung ◽  
2016 ◽  
Vol 70 (6) ◽  
pp. 547-555 ◽  
Author(s):  
Tianyi Zhan ◽  
Jiali Jiang ◽  
Hui Peng ◽  
Jianxiong Lu
Keyword(s):  
Cell Wall ◽  
Viscoelastic Properties ◽  
Loss Factor ◽  
Loss Modulus ◽  
Polymer Networks ◽  
Chinese Fir ◽  
Cunninghamia Lanceolata ◽  
Unstable State ◽  
Factor Ratios ◽  
Moisture Desorption

Abstract The viscoelasticity of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) during moisture desorption processes were examined at 30°C and two relative humidity (RH) modes: RHramp-down mode from 85 to 0% RH, and RHisohume mode at 0, 30, and 60% RH, respectively. Dynamic viscoelastic properties were determined in a multi-frequency range of 1, 2, 5, 10, and 20 Hz. In both RH modes, desorption of water resulted in increasing stiffness and decreasing damping. The reduction in moisture content caused an unstable state in the cell wall due to the formation of free volumes in cell wall and rearrangement of hydrogen bonds within the polymer networks. Higher ramping rates resulted in greater destabilization, and the unstable state was more pronounced at a lower frequency. The ratio of storage modulus at 1 and 20 Hz remained unchanged during both RH modes. The ratios of loss modulus and loss factor at 1 and 20 Hz increased during the RHramp-down and decreased during the RHisohume period. The changes of loss modulus or loss factor ratios at two frequencies were suitable for evaluation of the unstable state. The instability was aggravated with reducing RH and slightly recovered at constant RH.

Frequency-dependent viscoelastic properties of Chinese fir (Cunninghamia lanceolata) under hygrothermal conditions. Part 2: moisture desorption

Holzforschung ◽  
2019 ◽  
Vol 73 (8) ◽  
pp. 737-746 ◽  
Author(s):  
Tianyi Zhan ◽  
Jiali Jiang ◽  
Jianxiong Lu ◽  
Yaoli Zhang ◽  
Jianmin Chang
Keyword(s):  
Shift Factor ◽  
Chinese Fir ◽  
Cunninghamia Lanceolata ◽  
Damping Properties ◽  
Master Curves ◽  
Frequency Dependent ◽  
Wood Stiffness ◽  
Set Up ◽  
Stiffness And Damping ◽  
Moisture Desorption

AbstractThe frequency-dependent viscoelasticity of Chinese fir (Cunninghamia lanceolata) during moisture desorption was investigated and the applicability of the time-moisture superposition (TMS) relation on wood stiffness and damping during the moisture desorption was verified. The hygrothermal conditions for the moisture desorption were set up as six constant temperatures ranging from 30 to 80°C and three relative humidity (RH) levels at 0, 30 and 60%. Due to the elimination of water during the moisture desorption, the stiffness of the Chinese fir increased, whereas the damping decreased. With the increase in frequency, increased stiffness and decreased damping were observed. Utilizing the TMS relation, it was possible to construct master curves of wood stiffness at temperatures ranging from 30 to 80°C. The linear relationship between the shift factor and the moisture content (MC) manifested a low intermolecular cooperativity between the polymers and a narrow relaxation window. However, the TMS relation was not able to predict the wood damping properties during the moisture desorption, because wood is a multi-relaxation system. The non-proportional relationship between the free volume and MC during the moisture desorption may also explain why the TMS relation failed to construct master curves of the wood damping properties.

Solubilization of aluminum-bound phosphorus by root cell walls: evidence from Chinese fir, Cunninghamia lanceolata

2017 ◽  
Vol 47 (4) ◽  
pp. 419-423 ◽  
Author(s):  
Pengfei Wu ◽  
Guang-Yu Wang ◽  
Yousry A. El-Kassaby ◽  
Pan Wang ◽  
Xianhua Zou ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Chinese Fir ◽  
Cunninghamia Lanceolata ◽  
Tissue Type ◽  
Wall Material ◽  
Lateritic Soils ◽  
Significant Difference ◽  
Old Trees ◽  
Solubilizing Activity

This paper considered whether it was possible to activate nonavailable phosphorus (P) with tree root organs in lateritic soils. We investigated the cell wall content and P-solubilizing activity of xylem and phloem from six different sizes of roots from 10, 22, and 34 year old plantations of the Chinese fir Cunninghamia lanceolata (Lamb.) Hook. We found that, on average, cell wall content accounted for 81.07% of the root biomass (dry mass), and the mean solubilization of aluminum-bound phosphate by cell wall preparations was 1.89 g·kg−1. Tissue type (i.e., phloem or xylem) had a significant effect on cell wall content, with more cell wall material in the xylem, whereas P-solubilizing activity was greater in the phloem. In addition, the cell wall content of xylem increased with increasing root diameter, but P-solubilizing activity did not. A significant difference was also observed among the P-solubilizing activity of the three age classes, with lower P-solubilizing activity in the roots of 10 year old trees than in those of 22 and 34 year old trees. Since the establishment of Chinese fir plantations is increasing in southern China, where lateritic soils are widely distributed, the findings of the present study undoubtedly provide pertinent information for improving the utilization of nonavailable P by the cell walls of tree roots.

Influence of hygrothermal condition on dynamic viscoelasticity of Chinese fir (Cunninghamia lanceolata). Part 1: moisture adsorption

Holzforschung ◽  
2018 ◽  
Vol 72 (7) ◽  
pp. 567-578 ◽  
Author(s):  
Tianyi Zhan ◽  
Jiali Jiang ◽  
Jianxiong Lu ◽  
Yaoli Zhang ◽  
Jianmin Chang
Keyword(s):  
Cell Wall ◽  
Wood Cell Wall ◽  
Mechanical Analysis ◽  
Thermal Softening ◽  
Chinese Fir ◽  
Moisture Adsorption ◽  
Dynamic Viscoelasticity ◽  
Time Periods ◽  
The Difference ◽  
The Relationship

AbstractThe dynamic viscoelasticity of Chinese fir was investigated by dynamic mechanical analysis (DMA), while the influence of the moisture adsorption (MAds) was the focus of the study. The specimens were climatized at 30, 40, 50, 60, 70 and 80°C under two relative humidity (RH) modes. The RHrampmode included 0, 30, 60 and 90% RH with varied ramping rates (0.5, 1.0 and 2.0% RH min−1), while the RHisohumemethod worked with constant RHs of 30, 60 and 90%, respectively, for 60, 120 or 240 min. During the MAdsprocess, a decrease in stiffness and an increase in damping of the wood were seen and were attributed to the combination of the plasticization, mechano-sorptive (MS) effects and heating. High temperatures accelerate the MAdspace and intensify the plasticization and MS effects. In RHrampexperiments, the glass transition RH (RHg) of xylan was visible, as determined by the maximum of damping. The values of RHgvaried from 60 to 90% at 50°C or above. In the RHisohumemode, the thermal softening of hemicelluloses and lignin occurred for shorter time periods under more severe hygrothermal (HT) levels between 40–60°C and 70–80°C, respectively. During MAds, the MS effect diminished as the wood approached a new equilibrium moisture content (EMC). The MAdstimes to new EMCs became shorter at the expense of intensifying the unstable arrangement of the wood cell wall. Severe HT levels led to great residual instabilities in the wood cell wall, which could be evaluated by the relationship between the extent of the MS effect and the difference between the MC and EMC.

Age-dependent microRNAs in regulation of vascular cambium activity in Chinese fir (Cunninghamia lanceolata)

Trees ◽  
2021 ◽  
Author(s):  
Guijun Liu ◽  
Xian Xue ◽  
Jinling Feng ◽  
Dechang Cao ◽  
Jinxing Lin ◽  
...  
Keyword(s):  
Chinese Fir ◽  
Cunninghamia Lanceolata ◽  
Vascular Cambium ◽  
Age Dependent ◽  
Cambium Activity

Genetic parameters and genotype–environment interactions of Chinese fir (Cunninghamia lanceolata) in Fujian Province

2014 ◽  
Vol 44 (6) ◽  
pp. 582-592 ◽  
Author(s):  
Liming Bian ◽  
Jisen Shi ◽  
Renhua Zheng ◽  
Jinhui Chen ◽  
Harry X. Wu
Keyword(s):  
Genetic Parameters ◽  
Breeding Strategy ◽  
Chinese Fir ◽  
Breeding Program ◽  
Cunninghamia Lanceolata ◽  
Environment Interaction ◽  
Fujian Province ◽  
The Third ◽  
Genotype Environment Interaction ◽  
Sib Families

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is the most commercially important conifer in China, and the Nanjing Forestry University – Fujian Province Chinese fir Cooperation (NJFU – Fujian Cooperation) breeding program has advanced it into the third cycle of selection and breeding. In this paper, we estimated genetic parameters from four sites for 80 half-sib families and summarized previous estimates of genetic parameters in Chinese fir with an objective to propose optimal breeding strategy. Heritability averaged 0.20 and 0.14 for height and diameter at breast height (DBH), respectively, for the four sites. A significant genotype–environment interaction (G × E) for growth was also observed among the four sites, with the greatest interactions between a marginal site and the three central sites in the Fujian Province Chinese fir plantation region. The average estimated type-B genetic correlation between the marginal site and the three central sites was 0.08 for height and –0.09 for DBH. However, the highly productive families were among the most stable across the four sites. The results from this study in combination with summarized genetic parameters from literature were used to discuss and propose an optimal breeding strategy for the third generation of the breeding program for Chinese firs in Fujian Province.

scholarly journals Optimization of hormone combinations for root growth and bud germination in Chinese fir (Cunninghamia lanceolata) clone leaf cuttings

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Shubin Li ◽  
Peng Huang ◽  
Guochang Ding ◽  
Lili Zhou ◽  
Piao Tang ◽  
...  
Keyword(s):  
Root Growth ◽  
Chinese Fir ◽  
Cunninghamia Lanceolata
Sign in / Sign up

Export Citation Format

Share Document