在气中的压力下,在封闭过程中进行热修改后,树木的特性
Guntis Sosins1, Juris Grinins1, Prans Brazdausks1
1Latvian State Institute of Wood Chemistry, 27 Dzerbenes Str., LV-1006 Riga, Latvia.
Materials (Basel, Switzerland)
|December 17, 2024
概括
热修饰 (TM) 欧洲树木在尺寸稳定性和降低水分含量方面显著改善. 这种封闭的压力处理提高了抗膨胀效率,降低了水容量,使树木更耐用.
科学领域:
- 木材科学和材料改造.
- 森林产品技术. 森林产品技术.
背景情况:
- 热修饰 (TM) 是一种用于增强木材性能的工艺.
- 封闭的,加压的系统为TM过程提供了潜在的优势.
研究的目的:
- 为了研究密闭,压力热修饰对欧洲 (Populus tremula) 木材的影响.
- 描述经过处理的树木的物理和机械性能变化.
主要方法:
- 在340升的室中,在160-170°C的压力 (4-5bar) 下,在60-180分钟的时间内,对树木进行试验规模的热修饰.
- 对尺寸变化,质量损失 (ML),平衡水分含量 (EMC),抗膨胀效率 (ASE),细胞壁总水容量 (CWTWC),破裂模量 (MOR),弹性模量 (MOE) 和布林尔硬度 (BH) 的处理木材的表征.
主要成果:
- TM导致了5.4-14.5%的质量损失和显著的收缩.
- 抗膨胀效率 (ASE) 从22%到70%不等,细胞壁总水容量 (CWTWC) 从35%降至11-27%不等.
- 均衡水分含量 (EMC) 和体积膨胀 (VS) 减少了一半以上;机械性能变化 (MOR,MOE) 不显著,但布林尔硬度下降.
结论:
- 封闭式,压力热修饰有效地提高了尺寸稳定性,并降低了欧洲树木的与水分有关的特性.
- 该处理提供了一种有前途的方法,用于提高树木在各种应用中的耐用性.
更多相关视频
相关概念视频
Regulation of Transpiration by Stomata
During photosynthesis, plants acquire the necessary carbon dioxide and release the produced oxygen back into the atmosphere. Openings in the epidermis of plant leaves is the site of this exchange of gasses. A single opening is called a stoma—derived from the Greek word for “mouth.” Stomata open and close in response to a variety of environmental cues.
Adaptations that Reduce Water Loss
Though evaporation from plant leaves drives transpiration, it also results in loss of water. Because water is critical for photosynthetic reactions and other cellular processes, evolutionary pressures on plants in different environments have driven the acquisition of adaptations that reduce water loss.
Responses to Heat and Cold Stress
Every organism has an optimum temperature range within which healthy growth and physiological functioning can occur. At the ends of this range, there will be a minimum and maximum temperature that interrupt biological processes.
Softwoods and Hardwoods
Softwoods and hardwoods, derived from different types of trees, are distinguished by their leaf structures and cellular compositions, each serving unique purposes in construction and manufacturing. Softwoods come from cone-bearing trees with needle-like leaves and are predominantly composed of longitudinal cells called tracheids and a smaller proportion of radial cells known as rays. Due to their cellular structure, softwoods are commonly used in construction for structural frames, sheathing,...
Seasoning of Wood
Seasoning of wood is a crucial process aimed at reducing and stabilizing the moisture content within the wood to prevent future shrinkage, structural damage, or aesthetic issues once the wood is used in construction. Wood naturally swells when it absorbs moisture and contracts as it dries.
Achieving equilibrium moisture content is the goal of seasoning; this is the point where the wood's moisture content stabilizes to align with the moisture levels of the surrounding environment. Proper...
Achieving equilibrium moisture content is the goal of seasoning; this is the point where the wood's moisture content stabilizes to align with the moisture levels of the surrounding environment. Proper...
Drying Shrinkage
When hardened concrete is exposed to air with a relative humidity of less than 100 percent, it begins to lose the free water within its capillaries. As this water evaporates, the water initially adsorbed onto the calcium silicate hydrates migrates towards these now empty spaces and eventually evaporates as well. Over time, as more water leaves, the volume of the concrete decreases, a phenomenon known as drying shrinkage.
A portion of this drying shrinkage can be reversed; if the concrete is...
A portion of this drying shrinkage can be reversed; if the concrete is...


