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Wood grain is the longitudinal arrangement of wood fibers [1] or the pattern resulting from such an arrangement. [2] R. Bruce Hoadley wrote that grain is a "confusingly versatile term" with numerous different uses, including the direction of the wood cells (e.g., straight grain, spiral grain), surface appearance or figure, growth-ring placement (e.g., vertical grain), plane of the cut (e.g ...
Thermally modified wood is engineered wood that has been modified by a controlled pyrolysis process of wood being heated to (> 180 °C) in an oxygen free atmosphere. This process changes to the chemical structures of wood's cell wall components lignin , cellulose and hemicellulose which decreases its hygroscopy and thus increases dimensional ...
Ammonia fuming is a wood finishing process that darkens wood and brings out the grain pattern. It consists of exposing the wood to fumes from a strong aqueous solution of ammonium hydroxide which reacts with the tannins in the wood. The process works best on white oak because of the high tannin content of this wood.
Heat bending is the procedure of bending wood into different curves and shapes using moisture and a bending iron. By placing the wood into water, the moisture and heat from the bending iron will reform the structure of the wood, reorganizing the fibers of the wood to prevent the wood from springing back to its original state. [1]
Wood is an example of an orthotropic material. Material properties in three perpendicular directions (axial, radial, and circumferential) are different. In material science and solid mechanics, orthotropic materials have material properties at a particular point which differ along three orthogonal axes, where each axis has twofold rotational ...
When testing wood in lumber form, the Janka test is always carried out on wood from the tree trunk (known as the heartwood), and the standard sample (according to ASTM D143) is at 12% moisture content and clear of knots. [3] The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the ...
The constant volume adiabatic flame temperature is the temperature that results from a complete combustion process that occurs without any work, heat transfer or changes in kinetic or potential energy. Its temperature is higher than in the constant pressure process because no energy is utilized to change the volume of the system (i.e., generate ...
Cascade impactors – particulate matter is withdrawn isokinetically from a source and segregated by size in a cascade impactor at the sampling point exhaust conditions of temperature, pressure, etc. Cascade impactors use the principle of inertial separation to size segregate particle samples from a particle laden gas stream. The mass of each ...