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Pykrete (/ ˈ p aɪ k r iː t /, PIE-creet) [1] is a frozen ice composite, [2] originally made of approximately 14% sawdust or some other form of wood pulp (such as paper) and 86% ice by weight (6 to 1 by weight). During World War II, Geoffrey Pyke proposed it as a candidate material for a supersized aircraft carrier for the British Royal Navy.
The term brown rot replaced the general use of the term dry rot, as wood must be damp to decay, although it may become dry later. Dry rot is a generic name for certain species of brown-rot fungi. Brown-rot fungi of particular economic importance include Serpula lacrymans (true dry rot), Fibroporia vaillantii (mine fungus), and Coniophora ...
In the age of wooden ships, boats were sometimes hauled for the winter and placed in sheds or dry dock for repair. The boats already had some amount of rot occurring in the wood members, but the wood cellular structure was full of water making it still function structurally. As the wood dried out, the cell walls would crumble.
The log structure was made at least 476,000 years ago, while the wood tools are slightly younger, under 400,000 years old. That places the materials in a time before our species, Homo sapiens ...
Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is essential for recycling the finite matter that occupies physical space in the biosphere .
A few key ingredients need to come together for snow and ice to develop in the South. Cold air needs to be in place first. This typically happens a few times each winter when the polar jet stream ...
If this happens rapidly, the cells in the wood can shrink and collapse. This damage might be inevitable depending on accessibility to treatment. Additionally waterlogged wood should never be handled extensively or put on exhibit for long periods of time. Most waterlogged wood is such that decayed wood cells in the material fill with water.
Instead of cycling the wood in the chamber, heat can be added to the wood at a rate that matches the rate of sublimation of ice in the wood to water vapor, which is deposited on the inside of the chamber or in the cold trap. An advantage of freeze drying wood is that the form of the wood is maintained, and shrinkage does not typically occur.