Search results
Results from the WOW.Com Content Network
The attraction of wood for water arises from the presence of free hydroxyl (OH) groups in the cellulose, hemicelluloses and lignin molecules in the cell wall. The hydroxyl groups are negatively charged. Because water is a polar liquid, the free hydroxyl groups in cellulose attract and hold water by hydrogen bonding. Vapor
Sapwood (or alburnum [15]) is the younger, outermost wood; in the growing tree it is living wood, [16] and its principal functions are to conduct water from the roots to the leaves and to store up and give back according to the season the reserves prepared in the leaves. By the time they become competent to conduct water, all xylem tracheids ...
Lignum vitae is hard and durable, and is also the densest wood traded (average dried density: ~79 lb/ft 3 or ~1,260 kg/m 3); [4] it will easily sink in water. On the Janka scale of hardness, which measures hardness of woods, lignum vitae ranks highest of the trade woods, with a Janka hardness of 4,390 lbf (compared with Olneya at 3,260 lbf, [5] African blackwood at 2,940 lbf, hickory at 1,820 ...
Waterlogged wood is a wooden object that has been submerged or partially submerged in water and has affected the original intended purpose or look of the object. . Waterlogged wood objects can also include wood found within moist soil from archaeological sites, underwater archaeology, maritime debris, or damaged w
Harvesting of cork from the forests of Algeria, 1930. Cork is a natural material used by humans for over 5,000 years. It is a material whose applications have been known since antiquity, especially in floating devices and as stopper for beverages, mainly wine, whose market, from the early twentieth century, had a massive expansion, particularly due to the development of several cork-based ...
Fumed oak choir stalls at Clonfert Cathedral, Ireland. 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.
They are used on board ships to pump out flooded compartments: seawater is pumped to the eductor and forced through a jet, and any fluid at the inlet of the eductor is carried along to the outlet, and then up and out of the compartment. Eductors can pump out whatever can flow through them, including water, oil, and small pieces of wood.
Fibre saturation point is a term used in wood mechanics and especially wood drying, to denote the point in the drying process at which only water bound in the cell walls remains - all other water, called free water, having been removed from the cell cavities.