Predictability of color changes of wood used indoor - A new approach to evaluate the color change as a function of the radiation dose

室内木材颜色变化的可预测性 - 评估颜色变化随辐射剂量变化的新方法

• 批准号: 442135169
• 负责人: Professor Dr.-Ing. Alexander Pfriem
• 金额: --
• 依托单位: Institut für Holzforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/442135169?language=en
• 关键词: Predictability; color; changes; wood; used

The optical properties of wood show a high variety and depend on the chromophoric functional groups and chromophore systems present in the wood. Noticeable color variations are found both between different species as well as within a wood species. During natural aging, woodundergoes a color change, which is mainly caused by radiation of ultraviolet and visible light and the hereby induced photo-oxidation. The aim of this project is to convert key figures into a databased modelling in order to be able to evaluate the chemical and color changes of wood based on the radiation dose. This includes the evaluation of the changes via depth profiles. Overall, research problems are dealt with on the basis of the following hypotheses: • Color and chemical changes in wood during natural sunlight exposure indoors (t_n) and during artificially simulated UV/Vis exposure indoors (t_a) are known: a) If there are species-specific relationships between the two exposures, these can be described mathematically using a compensation curve. The parameters can be calculated using the generalized least squares estimation method. For the assumed relationship t_n = z * t_a, the shift factors (z) can then be determined.b) When light-induced color and chemical changes occur, these can be checked for correlations using a structure-discovering method from explorative data analysis and multivariate statistics (principal component analysis, PCA).c) If the irradiation exposures have short-term color and chemical effects, then long-term changes can be deduced via linear regressions.• If the sunlight exposure can be specified as a function of time, then it can also be specified as a function of radiation dose (accumulated area-based power density).• UV/Vis light filtered through window glass penetrates various types of wood at different depths: The further away the effect of surface-based radiation is from the wood surface, the lower the color and chemical changes. If the changes are attenuated with increasing penetration depth, this results in depth profiles in the wood substance that can be measured color-wise and chemically.• If the evaluation of the planned measurements as a function of radiation dose, rather than as a function of time, produces revealing findings, then changes can be predicted.• If new findings emerge from the preceding research hypotheses, then these must urgently be taken into account in material tests that are to be developed and tailored to the material wood.

木材的光学性质表现出高度的多样性，并且取决于木材中存在的发色官能团和发色团系统。在不同树种之间以及同一树种内部都发现了明显的颜色变化。在自然老化过程中，木材会发生颜色变化，这主要是由紫外线和可见光的辐射以及由此引起的光氧化引起的。该项目的目的是将关键数字转换成数据库模型，以便能够根据辐射剂量评估木材的化学和颜色变化。这包括通过深度剖面评估变化。总的来说，研究问题的基础上处理以下假设：·木材的颜色和化学变化在自然阳光照射室内（t_n）和人工模拟的UV/维斯暴露室内（t_a）是已知的：a）如果有物种之间的特定关系的两个曝光，这些可以用数学描述的补偿曲线。可以使用广义最小二乘估计方法来计算参数。对于假定的关系t_n = z * t_a，然后可以确定位移因子（z）。B）当发生光诱导的颜色和化学变化时，可以使用来自探索性数据分析和多元统计的结构发现方法来检查这些变化的相关性（主成分分析，PCA）。c）如果辐照暴露具有短期颜色和化学效应，则可以通过线性回归推导出长期变化。·如果日光照射量可以指定为时间的函数，则它也可以指定为辐射剂量的函数（基于面积的累积功率密度）。·透过窗户玻璃过滤的UV/维斯光穿透不同深度的各种类型的木材：基于表面的辐射的效果离木材表面越远，颜色和化学变化就越低。如果变化随着穿透深度的增加而减弱，则会在木材中产生可通过颜色和化学方法测量的深度剖面。·如果对计划测量值作为辐射剂量的函数（而不是时间的函数）进行评估，得出了有启发性的结果，则可以预测变化。·如果从前面的研究假设中出现了新的发现，那么在开发和定制材料木材的材料测试中必须立即考虑这些发现。