Wood production methods

Documented efforts at cokemaking date from 1584 (34), and have seen various adaptations of conventional wood-charring methods to the production of coke including the eventual evolution of the beehive oven, which by the mid-nineteenth century had become the most common vessel for the coking of coal (2). The heat for the process was suppHed by burning the volatile matter released from the coal and, consequently, the carbonization would progress from the top of the bed to the base of the bed and the coke was retrieved from the side of the oven at process completion. 

The final section in this volume deals with applications of adhesion science. The applications described include methods by which durable adhesive bonds can be manufactured by the use of appropriate surface preparation (Davis and Venables) to unique methods for composite repair (Lopata et al.) Adhesive applications find their way into the generation of wood products (Dunky and Pizzi) and also find their way into the construction of commercial and military aircraft (Pate). The chapter by Spotnitz et al. shows that adhesion science finds its way into the life sciences in their discussion of tissue adhesives. 

Arsenically treated wood. Discarded arsenically treated wood or wood products that are hazardous only because they exhibit certain toxic characteristics (e.g., contain harmful concentrations of metal or pesticide constituents), are excluded from the definition of hazardous waste. Once such treated wood is used, it may be disposed of by the user (commercial or residential) without being subject to hazardous waste regulation. This exclusion is based on the fact that the use of such wood products on the land is similar to the common disposal method, which is landfilling. This exclusion applies only to end-users and not to manufacturers. 

Post-column derivatization of carbohydrates has been described for liquid chromatography and UV detection by heat treatment [46], acid treatment [47] and reaction with phenol-sulfuric acid [48,49]. These methods have been applied to the analysis of sugars in body fluids and in wood products. The procedures are only suitable for low-speed liquid chromatography. 

To expand the usefulness of wood products, it is often desirable to increase the physical strength, improve chemical resistance, and slow degradation. One method of effecting these changes is to impregnate the porous wood... 

Studies are currently being conducted on smoke development and heat release rate from treated and untreated wood and wood products (52,56). An evaluation of the available treatment systems for wood shingles and shakes was completed using artificial weathering (11). A further development from this work was a new ASTM Standard Method D2898 (67,68) for testing durability of fire-retardant treatment of wood. 

As new criteria are developed for defining combustibility, a method is needed to realistically indicate heat release rate of wood products exposed to building fires instead of dependence on "total heat values."... 

Test Methods for Integrity of Glue Joints in Structural Laminated Wood Products for Exterior Use... 

The name potash derives from an early production method in which potassium carbonate, leached from wood ashes, was crystallized by evaporating the leachate in large iron pots. The salt potassium chloride (muriate of potash or KC1) is now the major source of the element (95%) other important salts are potassium sulfate (sulfate of potash, K2S04), potassium magnesium sulfates of varying K/Mg ratios, and potassium nitrate (KN03). 

Depending on the chlorophenol formulations, the total amount of PCDEs in chlorophenols and chlorophenol-based wood preservatives have varied from 4.4 mg kg-1 to 1000 mg kg 1 [37-43]. PCDEs have not been observed in dichlo-rophenols [37] and the level reported for a trichlorophenol was low [4]. Examples of the content of PCDEs in different chlorophenol formulations have been presented in Table 4. The concentrations of the most toxic by-products in chlorophenols, PCDDs, are also at mg kg"1 levels or higher [33,37,39-42,47]. The content of by-products in chlorophenols including PCDEs depend on the production method [42]. 

These figures match closely the world wide mean of 7.3 t ha-i yr of aboveground biomass production estimated with various methods (Jordan 1983). This result confirms earlier findings (Medina and Klinge 1983, Jordan 1983) that wood production in tropical forests, even under good nutrient conditions like in the varzea, does not exceed the wood production of temperate forests. The sum of the aboveground wood production and of the coarse and fine litter production leads to aboveground primary production (NPP). Within the varzea the... 

The poly-phenols or poly-hydroxy benzenes are obtained from the dry distillation products of wood. The methods of synthesis are in general those for the mono-phenols though the diazo reaction does not usually work well with amino phenols. Also some of the methods of preparation used for poly-phenols do not apply to the mono-phenols. In general properties they resemble the mono-compounds, but they are usually more easily soluble in water, react more readily and are characterized by their strong reducing properties. 

The anhydride method of acetylation gives an acid by-product that results in an acidic condition in the wood and a loss of 50% of the reaction chemical. These by-products must be removed to prevent degradation. Acetic acid, the by-product of acetylation with acetic anhydride, is virtually impossible to remove completely from wood. This results in a product that smells of acetic acid, acid conditions that catalyze the removal of more acetyl groups, acid hydrolysis of cellulose fibers which results in strength losses over a long term, and acid corrosion of metal fasteners used in the wood product. 

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