نتایج جستجو برای: poplar wood
تعداد نتایج: 42866 فیلتر نتایج به سال:
Microwave and conventional acetylation of wood was carried out to determine its efficacy on the material properties. Beech (Fagus sylvatica L.) and poplar (Populus hybrids) samples with dimensions 14 mm × 14 mm × 14 mm were impregnated using acetic anhydride, and chemical reactions were initiated by microwave and conventional heating. The microwave acetylation process was carried out using labo...
One of the most persistent problems with mechanically densified wood is its inherent dimensional instability. The effects of heat post-treatment on the changes in spring-back (SB), compression ratio recovery (CRR), thickness swelling (TS), and water absorption (WA) of newly-tested Uludağ fir (Abies bornmuelleriana Mattf.) and black poplar (Populus nigra L.) wood samples that had been thermo-mec...
If a tree survives a fall in thewoods, themain stemgrowsupward from its newposition. In angiosperm trees, this growth reorientation is achieved via differential activity in the cambium, which produces tension wood on the side of the stem now facing upward and opposite wood on the bottom side (Ruelle, 2014). Whereas opposite wood is phenotypically similar to “normal” wood formedbyupright stems, ...
In order to face environmental constraints, trees are able to re-orient their axes by controlling the stress level in the newly formed wood layers. Angiosperms and gymnosperms evolved into two distinct mechanisms: the former produce a wood with large tension pre-stress on the upper side of the tilted axis, while the latter produce a wood with large compression pre-stress on the lower side. In b...
Acetylation of wood imparts moisture durability, decay resistance, and dimensional stability to wood; however, making durable adhesive bonds with acetylated wood can be more difficult than with unmodified wood. The usual explanation is that the acetylated surface has fewer hydroxyl groups, resulting in a harder-to-wet surface and in fewer hydrogen bonds between wood and adhesive. This concept w...
Wood is formed by the successive addition of secondary xylem, which consists of cells with a conspicuously thickened secondary wall composed mainly of cellulose, xylan and lignin. Currently, few transcription factors involved in the direct regulation of secondary wall biosynthesis have been characterized in tree species. Here, we show that PdMYB221, a poplar ortholog of the Arabidopsis R2R3-MYB...
Characterization of Emissions from Thermally Modified Wood and Their Reduction by Chemical Treatment
Thermal treatment is a suitable method for improving the quality of wood types like spruce, beech, or poplar, and thus to open up new fields of application that used to be limited to tropical woods or woods treated with timber preservatives. These thermally treated woods are characterized by a typical odor caused by degradation products of miscellaneous wood components. The characterization and...
Laminated veneer lumbers (LVLs) were manufactured from half-round sliced I-214 hybrid poplar clone veneers with MUF adhesives using press pressures ranging from 2.5 to 15 kg cm -2 . The results showed that the press pressures affected the glue line thickness (GLT) and the physical and mechanical properties of the LVLs. Higher specific gravity (SG) and mechanical properties, but lower GLT were d...
The contents of polycyclic aromatic hydrocarbons (PAH) in Frankfurtertype sausages were investigated in depency on hot smoking conditions (glow smoke), type of casing, back fat content and different types of wood chips. For the smoking experiments three different types of smoke densities and ventilator velocities, three types of casings, four different back fat contents (10%, 20%, 30%, and 39%)...
The aim of this paper is to develop a strategic plan for selecting the best options for the supply of raw material to feed paper producing plants. The decision-making is examined within the framework of benefits, opportunities, costs, and risks (BOCR). A hierarchy is used to prioritize the BOCR, using the Analytic Hierarchy Process (AHP) ratings approach. A control hierarchy is then created and...
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