Effect of Bordered Pit Torus Position on Permeability in Chinese Yezo Spruce

The effect of different bordered pit torus positions on wood permeability was studied by air-drying and ethanol-exchange drying for green wood and by soaking in water, then followed by ethanol-exchange drying for air-dried wood of Chinese yezo spruce (Picea jezoensis var. komarovii). The results showed that different treatments caused different pit torus positions and different wood permeability. The air-drying treatment resulted in pit torus aspiration and low permeability for sapwood. The ethanol-exchange drying treatment left the pit torus in an unaspirated position and resulted in high permeability for sapwood. Soaking in water followed by ethanol-exchange drying caused deaspiration of a part of pit torus and increased permeability for both sapwood and heartwood

Compression Strength and Modulus of Elasticity Parallel to the Grain of Oak Wood at Ultra-low and High Temperatures

The influence of temperature on the compression strength (fc0) in the range of -196 ºC to +220 ºC, and compression modulus of elasticity (Ec0) parallel to the grain of oak (Quercus mongolica Fisch et Turcz.) wood in the range of -196 ºC to +23 ºC were studied. Five specimens were prepared for each temperature level. The specimens were kept at each temperature level for 30 min before a mechanical test was performed in an adjustable-temperature chamber. The results indicated that there were four different failure patterns, depending on the temperature range. When the temperature was decreased from +23 ºC to -196 ºC, the fc0 and Ec0 of wood increased by 283.91% and 146.30%, respectively. The relationships between fc0 and temperature and between Ec0 and temperature could be described by a linear and a polynomial model, respectively. Moreover, the Ec0 could be used to predict fc0 using a polynomial model. However, when the temperature was increased from +23 ºC to +220 ºC, the fc0 decreased by 67%, indicating a non-linear relationship

Constructing ecological-protecting barrier: Basic research of rainfall runoff regulation and application in the Loess Plateau of China and its implications for global arid areas

Loess Plateau is one of most eco-fragile and poverty-stricken areas in China. Drought and soil erosion are the two major obstacles to restrict economic development here. Rainfall runoff is the leading factor causing soil and water loss in this region. Rainfall runoff regulation and utilization is the inheritance, innovation and development for scientific theories of soil and water conservation in the Loess Plateau, which gives prominence to scientific gathering and detracting of rainfall runoff in terms of space and time and emphasizes on solving the drought and soil erosion by active control means and realizes the unity of regulation, preservation and utilization of rainfall runoff in space and time. The paper analyzed the progress of the applied research of rainfall runoff regulation and utilization from 4 aspects, such as the operational rules of rainfall runoff, the potential of rainfall runoff regulation and utilization, the optimal allocation of rainfall runoff and the environmental effects of rainfall runoff regulation and utilization. It also made the analysis on the current situation of rainfall runoff utilization technology. At last, the paper suggested some cases for rainfall runoff regulation and utilization in the Loess Plateau. Rainfall runoff not only brings about the integration of ecological reconstruction with economic development in the Loess Plateau, but also provides a new approach to the sustainable development as well as removing two of the biggest stumbling blocks, drought and soil erosion, in the Loess Plateau of China, which will provide more information for rainfall runoff utilization in the arid areas of the world

Cell Wall Property Changes of White Rot Larch during Decay Process

Larch flakes infested with white rot fungus were examined following several infestation durations with respect to the mass loss, tensile strength, hardness, porosity, and change in cell wall components. Nano-indentation, X-ray diffraction (XRD), nitrogen adsorption, and Fourier transform infrared (FTIR) spectroscopy testing methods were employed to investigate the property changes during the decay process. The testing results showed that the mass loss was greater and the longitudinal tensile strength decreased following the first three-week infestation. Nano-indentation measurements revealed that the average MOE of infested larch flakes decreased from 24.0 to 17.1 GPa and the average hardness declined from 528.47 to 427.87 MPa following 12 weeks of infestation. After the first three weeks, the relative crystallinity, surface area, and micropore area of the infested samples increased. These parameters decreased after three weeks had elapsed. Changes in the absorption peaks observed in FTIR explained that the first three-week infestation had a strong effect on the mass loss and strength changes. This suggests that white rot fungus intensely attacked the lignin component of the biomass during the first three weeks of infestation