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Saturday 6 August 2016

Industry Prospective of Delamination in Wood and Wood Products

Published Date
pp 215-236
Date: 

Title 

Industry Prospective of Delamination in Wood and Wood Products

  • Author 
  • Chih Lin Huang 

Abstract

The highly-competitive forest industry is facing mounting pressures from both substitutions and imports. The North America industry is not only adjusting to the changing wood quality and timberland ownership but is also coping with the cyclical downturn of the market. It is very challenging to balance high-mill throughput and lumber quality to meet customer needs while remaining profitable in a rapidly changing industry. Logistics costs and governmental regulations are just a couple of obstacles to overcome. These hurdles are unappreciated by those with little experience in the operations. Of the many great ideas presented, only a few are operationally feasible. For example, while it is possible to sort raw materials at various stages throughout the value chain to reduce lumber variability, such efforts may not be cost-effective for the following reasons:


References

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  3. Floyd S (2005) Effect of hemicellulose on longitudinal shrinkage in wood. In Entwistle K, Walker JCF (eds) The hemicellulose workshop 2005. Wood Technology Research Center, University of Cantebury, Christchurch, pp 115–120
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For further details log on website :
http://link.springer.com/chapter/10.1007/978-90-481-9550-3_11

Delamination in Timber Induced by Drying

Published Date
pp 197-212
Date: 

Title 

Delamination in Timber Induced by Drying

  • Author 
  • Nawshad Haque

Abstract

In the context of wood drying, delamination can be regarded as a defect due to poor drying where separation between wood fiber cells occurs on surface (surface checks) or inside of wooden boards (internal checks) and in the form of splits (i.e. end split) at the end of the timber board. Solid wooden board can be considered as naturally laminated product. Before discussing delamination aspect of wood fibers during drying in further detail, it is helpful to discuss about basic principles and purpose of wood drying.


References

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For further details log on website :
http://link.springer.com/chapter/10.1007/978-90-481-9550-3_10

Delaminations Induced by Weathering in Wood and Wood-Based Composites Panels

Published Date
pp 173-196
Date: 

Title 

Delaminations Induced by Weathering in Wood and Wood-Based Composites Panels

  • Author 
  • Voichita Bucur

Abstract

The term “weathering” (Feist 1982) defines any of the physical, mechanical or chemical process by which wood or wood based products undergo slow degradation induced by the weather (sunlight, wind, precipitations, diurnal and seasonal changes in relative humidity, atmospheric pollution, etc). Knowledge about weathering durability comes from practical experiences of end-users, from field tests and from standardized laboratory tests. The weathering process affects only the surface of wood or wood products. It was primarily accepted that the sunlight- ultraviolet radiation, visible and infrared radiation- initiate the wood weathering. (Williams 2005). The UV radiation has sufficient energy to degrade lignin and carbohydrates, while the visible light degrades wood extractives. Wood photo – degradation starts after exposure to the sunlight (Bentum and Addo-Ashong 1977; Derbyshire and Miller 1981, 1995; Groves and Banana 1986; Onishi et al. 1989). This process is very slow and is of about 5 mm thickness decreasing of a board during 100 years (Feist and Mraz 1978). In Table 9.1 are given some values of the erosion of earlywood and latewood of different species exposed to the North American climate for a period ranging from 4 to 16 years. Erosion values for plywood made from different species are given in Table 9.2. The erosion of earlywood is always greater than that of latewood. The ratio between the erosion of latewood and earlywood in solid wood, after 4 years of exposure varies between 2.37 and 2.5. The same ratio is different after 16 years of outdoor exposure and varies between 1.52 and 2.9 depending on species. For the plywood, after 4 years of exposure this ratio varies between 2.45 for Douglas fir and 3.2 … 3.4 for Western red cedar and redwood plywood. After 16 years of outdoor exposure the variation of this ratio is very small and is between 1.75 for Douglas fir plywood and 1.46 for Western red cedar plywood and redwood plywood.


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