Named the 9 fastest growing education company in the United States. Thank you for your support! She also granted Wood the exclusive right to market her designs and sell them. Wood filed suit, claiming breach of contract.
Many properties of wood show considerable change as the wood is dried below the fibre saturation point, including: Equilibrium moisture content[ edit ] Main article: Equilibrium moisture content Wood is a hygroscopic substance. It has the ability to take in or give off moisture in the form of vapour.
Water contained in wood exerts vapour pressure of its own, which is determined by the maximum size of the capillaries filled with water at any time. If water vapour pressure in the ambient space is lower than vapour pressure within wood, desorption takes place. The largest-sized capillaries, which are full of water at the time, empty first.
Vapour pressure within the wood falls as water is successively contained in smaller capillaries. A stage is eventually reached when vapour pressure within the wood equals vapour pressure in the ambient space above the wood, and further desorption ceases.
The amount of moisture that remains in the wood at this stage is in equilibrium with water vapour pressure in the ambient space, and is termed the equilibrium moisture content or EMC Siau, Because of its hygroscopicity, wood tends to reach a moisture content that is in equilibrium with the relative humidity and temperature of the surrounding air.
The EMC of wood varies with the ambient relative humidity a function of temperature significantly, to a lesser degree with the temperature. Siau reported that the EMC also varies very slightly with species, mechanical stress, drying history of wood, density, extractives content and the direction of sorption in which the moisture change takes place i.
Moisture content of wood in service[ edit ] Wood retains its hygroscopic characteristics after it is put into use. It is then subjected to fluctuating humidity, the dominant factor in determining its EMC.
These fluctuations may be more or less cyclical, such as diurnal changes or annual seasonal changes. To minimize the changes in wood moisture content or the movement of wooden objects in service, wood is usually dried to a moisture content that is close to the average EMC conditions to which it will be exposed.
These conditions vary for interior uses compared with exterior uses in a given geographic location. The primary reason for drying wood to a moisture content equivalent to its mean EMC under use conditions is to minimize the dimensional changes or movement in the final product.
Shrinkage and swelling[ edit ] Shrinkage and swelling may occur in wood when the moisture content is changed Stamm, Shrinkage occurs as moisture content decreases, while swelling takes place when it increases.
Volume change is not equal in all directions. The greatest dimensional change occurs in a direction tangential to the growth rings. Shrinkage from the pith outwards, or radially, is usually considerably less than tangential shrinkage, while longitudinal along the grain shrinkage is so slight as to be usually neglected.
The longitudinal shrinkage is 0.
Tangential shrinkage is often about twice as great as in the radial direction, although in some species it is as much as five times as great. Differential transverse shrinkage of wood is related to: This section has an unclear citation style.
The references used may be made clearer with a different or consistent style of citation and footnoting. August Learn how and when to remove this template message Wood drying may be described as the art of ensuring that gross dimensional changes through shrinkage are confined to the drying process.
Ideally, wood is dried to that equilibrium moisture content as will later in service be attained by the wood.
Thus, further dimensional change will be kept to a minimum. It is probably impossible to completely eliminate dimensional change in wood, but elimination of change in size may be approximated by chemical modification.
For example, wood can be treated with chemicals to replace the hydroxyl groups with other hydrophobic functional groups of modifying agents Stamm, Among all the existing processes, wood modification with acetic anhydride has been noted for the high anti-shrink or anti-swell efficiency ASE attainable without damage to wood.
However, acetylation of wood has been slow to be commercialised due to the cost, corrosion and the entrapment of the acetic acid in wood.
There is an extensive volume of literature relating to the chemical modification of wood Rowell,; Kumar, ; Haque, Wood drying (also seasoning lumber or wood seasoning) reduces the moisture content of wood before its use.
When the drying is done in a kiln, the product is known as kiln-dried timber or lumber, whereas air drying is the more traditional method.. There are two main reasons for drying wood: Woodworking: when wood is used as a construction material, whether as a structural support in a building.
The Natural Gas Hydrate Systems Gordon Research Conference will aim to link the latest advances on our understanding of gas hydrate science at the most fundamental level to the current research issues of scientific, economic and societal relevance. As Gordon Wood takes the stand in his case against the state of NSW, take a look back at the main events which led to his conviction and later acquittal of the murder of Caroline Byrne.
NSWs most senior prosecutor, Mark Tedeschi QC, has been accused of putting a little drop of illegitimate poison into the mind of the jury at Gordon Woods trial by using wishy washy evidence to.
Community Service - Memorial Flag Cases. The Diablo Woodworkers became engaged in honoring fallen firefighters, police officers and military shortly after the September 11, disasters in New York City and Washington, D.C.
Fulfillment by Amazon (FBA) is a service we offer sellers that lets them store their products in Amazon's fulfillment centers, and we directly pack, ship, and provide customer service for these products.