Li Yan
Northwest A&F University
Composite materialMaterials scienceGlycerolBoronActivation energy
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Publications 7
#1Zhenju Bi (NWAFU: Northwest A&F University)H-Index: 1
#2Fangxia Yang (NWAFU: Northwest A&F University)H-Index: 1
Last. Li Yan (NWAFU: Northwest A&F University)H-Index: 3
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Abstract Public concern for the environment has stimulated the development of natural wood preservatives. The antifungal activity of konjac (Amorphophallus konjac K. Koch) flying powder (a by-product produced during mechanical processing of konjac flour) ethanol extracts was evaluated against wood decay fungi in poplar (Populus nigra L.). Compounds associated with antifungal activity in the extracts were isolated and purified by silica gel column chromatography. The antifungal active fractions w...
2 CitationsSource
#1Kendall Conroy (OSU: Oregon State University)H-Index: 2
#2Li Yan (NWAFU: Northwest A&F University)H-Index: 3
Last. Chris Knowles (OSU: Oregon State University)H-Index: 6
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Although thermal modification is primarily used to improve wood durability, it also has a tendency to darken lighter colored hardwoods to make them more valuable. This process might also be useful for darkening softwoods, but it will be important to develop colors that customers prefer. One potential species for this application is Douglas-fir (Pseudotsuga menziesii). Consumer preferences for differing degrees of thermal modification (i.e. darkening) were assessed using a convenience sampling su...
#1Li Yan (NWAFU: Northwest A&F University)H-Index: 3
#2Fei-yang Zeng (NWAFU: Northwest A&F University)
Last. Yafang Lei (NWAFU: Northwest A&F University)H-Index: 1
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Trichoderma viride can infect wheat straw composites (WSC), thus affecting the quality of boards. This study investigated the change in color of the composite and its chemical composition after the straw was infested with mold with for 4, 8, or 12 weeks. Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC) were used to analyze chemical structural changes in the WSC after the infestation. The infested surface and core layers were examined and analyzed. ...
#1Li Yan (NWAFU: Northwest A&F University)H-Index: 3
#2Jeffrey J. Morrell (OSU: Oregon State University)H-Index: 20
The effects of borate and glycerol impregnation of Douglas-fir heartwood prior to open-air oven thermal modification at 160–200 °C for 2–4 h on wood color were measured. These materials were used to analyze the effects of modifying agents on thermal decomposition of wood by color nondestructive assessments. Kinetic analysis using time–temperature superposition and the horizontal shift factor were employed to quantify color changes. Lightness values were significantly affected by heating time and...
#1Rui Liu (NWAFU: Northwest A&F University)H-Index: 1
#2Jeffrey J. Morrell (OSU: Oregon State University)H-Index: 20
Last. Li Yan (NWAFU: Northwest A&F University)H-Index: 3
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The effects of glycerol pretreatment and thermal modification on poplar wood was examined using thermogravimetric analysis (TGA). The total mass losses of thermally-treated samples before and after glycerol impregnation were studied. The thermal degradation process was divided into three stages based on natural breaks in the slope of the TGA curves. The set-on and set-off temperatures, mass loss, and activation energy (Ea) of each stage were compared. Pretreatment with 60% glycerol followed by t...
4 CitationsSource
Abstract Most thermal modification studies have attempted to improve the durability of sapwood; however, it may be more fruitful to improve the durability of heartwood that already has some inherent durability. The effects of pretreatments with boron or glycerol coupled with thermal modification on resistance to mold growth and fungal degradation were examined for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) heartwood, which is classified as moderately durable. Pretreatment with boron had ...
2 CitationsSource
#1Li Yan (NWAFU: Northwest A&F University)H-Index: 3
#2Jeffrey J. Morrell (OSU: Oregon State University)H-Index: 20
The flexural properties, mass losses, and moisture behavior of thermally modified Douglas-fir pretreated with boron or glycerol were examined. Pretreatments were associated with slight, but not significant, reductions in modulus of rupture (MOR) and modulus of elasticity (MOE) of Douglas-fir at different thermal treatment levels. Boron pretreatment had the greatest effect on MOR. MOR of non-pretreated and boron-treated samples increased slightly at the initial stage of thermal treatment and then...
5 CitationsSource