Category: General Technical Reports
File size: 5438 kb(s)

Abstract: This report provides an assessment of technology used in manufacturing modular homes in the United States, and that used in the German prefabricated wooden home industry. It is the first step toward identifying the research needs in automation and manufacturing methods that will facilitate mass customization in the home manufacturing industry. Within the United States, a relatively low level of technology was found in domestic modular home manufacturers. Raw material transportation was mostly manual; manually operated saws sized raw materials; cranes were used to move subassemblies, and modules were pushed by hand or with a battery-powered pusher. German prefabricated home manufacturers used closed panels to construct walls, roofs, and floors rather than modular construction. Three levels of automation were identified: manual, semi-automated, and fully automated. Manual production methods were similar to those found in the United States. In semi-automated factories, automated machinery was used, but an operator was required to manually load, unload, and start the machine. The fully automated factories had equipment capable of machining and transferring panel components and placing and fastening components together. Such investment in automation is risky in the cyclic housing industry. The modular factory has elevated homebuilding from a craft to mass production, but flexibility is reduced and significant customization is difficult. Future research should examine the cost effectiveness of using high levels of automation, software, and equipment in the U.S. homebuilding industry and whether it can profitably provide the manufacturing flexibility for mass customization. Alternatively, the use of lean manufacturing in modular home factories to realize the same benefits needs to be examined.

Keywords: stick-built; automation trends; modular home industry; wood-frame housing; factory built housing; home prefabrication; closed-wall panels; systems-built housing

Category: Journal Articles
File size: 339 kb(s)

Abstract: A new species of Ernobius is described from material collected at the Griffith State Nursery in Wood County, Wisconsin, U.S.A. Ernobius youngi new species is described from a single adult female bringing the number of Ernobius species known from North America north of Mexico to 31.

Keywords: Ptinidae, Ernobius, Nearctic, Wisconsin

Category: Journal Articles
File size: 369 kb(s)

Abstract: This two-part analysis of the most feasible and effective URXWHV Ior the pulp and paper and forest products industry to add energy, biofuels and biobased chemicals to WKHLU Hxsting product streams was conducted by the American Forest & Paper Association's Agenda 2020 Technology Alliance. A full, detailed presentation of this analysis will take place during the special bridge session linking TAPPI's 2008 Engineering, Pulping and Environmental Conference with its 2008 International Bioenergy and Bioproducts Conference being conducted as back-to-back events at the same venue in Portland, OR, Aug. 24-27 and Aug. 27-29, respectively.

Keywords: Integrated, Forest Products, Thermochemical, Biorefinery

Category: Journal Articles
File size: 440 kb(s)

Abstract: This two-part analysis of the most feasible and effective URXWHV Ior the pulp and paper and forest products industry to add energy, biofuels and biobased chemicals to WKHLU Hxsting product streams was conducted by the American Forest & Paper Association's Agenda 2020 Technology Alliance. A full, detailed presentation of this analysis will take place during the special bridge session linking TAPPI's 2008 Engineering, Pulping and Environmental Conference with its 2008 International Bioenergy and Bioproducts Conference being conducted as back-to-back events at the same venue in Portland, OR, Aug. 24-27 and Aug. 27-29, respectively.

Keywords: Integrated, Forest Products, Thermochemical, Biorefinery

Category: Journal Articles
File size: 477 kb(s)

Abstract: Flakeboards made from control flakes bonded with an isocyanate resin outperformed phenolic-bonded control boards in thickness swelling tests in both liquid water and water vapour. Less irreversible swelling occurred in isocyanate-bonded control boards as compared to phenolic-bonded control boards. Flakeboards made from acetylated flakes, using either a phenolic or isocyanate resin, swelled in thickness much slower and to a lesser extent in liquid water and water vapour tests compared to control boards. Isocyanate-bonded control and acetylated aspen flakeboards had higher internal bond and modulus of rupture values and approximately equal modulus of elasticity properties when compared to a similar series of boards bonded with a phenolic resin, as reported in Part 1 of this series.

Keywords: acetylation; isocyanate adhesives; internal bond; dimensional stability; strength; flakeboard

Category: Journal Articles
File size: 538 kb(s)

Abstract: Near infrared (NIR) spectroscopy is now a widely-used technique in the field of forest products, especially for physical and mechanical property determinations. This technique is also ideal for the chemical analysis of wood. There has been a growing need to find a rapid, inexpensive and reliable method to distinguish between preservative-treated and untreated waste wood. It has been demonstrated that NIR spectroscopy, with multivariate analysis (MVA), can be used to distinguish between different preservative treatments. This technique is rapid, non-destructive, portable and relatively low cost. The results clearly demonstrate that this technique has potential for use in a variety of recycling and sorting applications. It has also been successfully used to predict preservative concentrations present in treated wood. A custom-made NIR scanning system, NIRVANA (Near Infrared Visual and Automated Numerical Analysis), was used for the automated scanning and prediction of preservative concentration along cross sections of ACQ-treated timbers. This may have potential for use as a quality control tool for wood treaters, especially for use with organic co-biocides, for which the preservative penetration and concentration cannot be readily assessed.

Keywords: Near infrared spectroscopy, NIR, preservatives, treated-wood, screening, concentration, penetration

Category: Journal Articles
File size: 245 kb(s)

Abstract: Soy flour is an inexpensive raw material for adhesives and is readily available in most parts of the world. However, converting soy flour into a wood adhesive that can compete in both cost and performance with existing petroleum-based adhesives is not easy given the variables of flour quality, denaturation conditions, and curing methods. Formulating adhesives that alter these variables is more readily accomplished than is testing the performance of these formulations using standard evaluation methods. To overcome this problem, we developed a rapid and reproducible small-scale bond strength testing procedure that allows us to screen new adhesives more efficiently. This procedure, employing the automated bond evaluation system (ABES) instrument, has led to improved soy adhesive formulations for plywood and other wood-bonding applications. Additionally, this procedure has been compared with standard product performance tests for decorative and exterior plywood using the common commercially available adhesives poly(vinyl acetate), urea-formaldehyde, melamine-urea-formaldehyde, and phenol-formaldehyde.

Keywords: soy, adhesives, plywood,bond evaluation, shear

Category: Journal Articles
File size: 248 kb(s)

Abstract: In 2008, the countries of the UNECE region accounted for about 55% of the world's production and consumption of paper and paperboard, and they produce nearly three fourths of the world's woodpulp, used to make paper and paperboard. Europe produces slightly more paper and paperboard than North America but less woodpulp, with European producers relying more on recycled fibre than producers in North America. The United States remains the world's largest producer and consumer of pulp, paper and paperboard. Outside the UNECE region, China is rapidly gaining ground as the second largest producer and consumer of paper and paperboard worldwide. Much of China's rapid growth is based on recycled fibre and imported pulp. Rapid expansion of Chinese pulp and paper production capacity is having a huge impact on paper and paperboard markets, and on global competition for wood, recovered paper, and pulp.

Keywords: pulp, paper, paperboard, market trends, Europe, North America

Category: Journal Articles
File size: 377 kb(s)

Abstract: Surfactant distributions in model pressure-sensitive adhesive (PSA) films were investigated using atomic force microscopy (AFM) and confocal Raman microscopy (CRM). The PSAs are water-based acrylics synthesized with n-butyl acrylate, vinyl acetate, and methacrylic acid and two commercially available surfactants, disodium (nonylphenoxypolyethoxy)ethyl sulfosuccinate (anionic) and nonylphenoxypoly(ethyleneoxy) ethanol (nonionic). The ratio of these surfactants was varied, while the total surfactant content was held constant. AFM images demonstrate the tendency of anionic surfactant to accumulate at the film surfaces and retard latex particle coalescence. CRM, which was introduced here as a means of providing quantitative depth profiling of surfactant concentration in latex adhesive films, confirms that the anionic surfactant tends to migrate to the film interfaces. This is consistent with its greater water solubility, which causes it to be transported by convective flow during the film coalescence process. The behavior of the nonionic surfactant is consistent with its greater compatibility with the polymer, showing little enrichment at film interfaces and little lateral variability in concentration measurements made via CRM. Surfactant distributions near film interfaces determined via CRM are well fit by an exponential decay model, in which concentrations drop from their highs at interfaces to plateau values in the film bulk. It was observed that decay constants are larger at the film-air interface compared with those obtained at the film-substrate side indicating differences in the mechanism involved. In general, it is shown here that CRM acts as a powerful compliment to AFM in characterizing the distribution of surfactant species in PSA film formation.

Keywords: Adhesives, surfactant, water

Category: Journal Articles
File size: 274 kb(s)

Abstract: The correlations between the intrinsic viscosity of fiber suspensions and 17 measures of fiber shape were investigated. The intrinsic viscosities of suspensions of fibers with various shapes and aspect ratios were determined numerically. The shapes studied include different degrees of fiber curvature, angular bends, helical shapes, randomly generated shapes, and others. The shape measure that correlated most strongly with intrinsic viscosity was an invariant of the hydrodynamic resistance tensor; this invariant is related to the hydrodynamic drag coefficients on a fiber translating in the three principal directions. This measure can be computed from 3D images of real fibers, and could potentially be a useful quantity for describing fiber shape. These results also suggest that experimentally-measured intrinsic viscosities can be used to characterize fiber shape, either directly or by extracting the invariant from experimental data.

Keywords: Fiber shape, Shape measure, Intrinsic viscosity, Simulations

Category: Journal Articles
File size: 176 kb(s)

Abstract: In the past, gravimetric corrosion data for fasteners exposed to treated wood has been reported as a percent weight loss. Although percent weight loss is a valid measure of corrosion for comparing identical fasteners, it can distort the corrosion performance of fasteners with different geometries and densities. This report reevaluates a key report on the corrosiveness of wood treated with chromated copper arsenate (CCA) and ammoniacal copper arsenate (ACA) and converts the previous data into corrosion rates. In addition, similar experiments were run in wood treated with alkaline copper quaternary (ACQ). Comparison of the corrosion rates reveals ACQ treated wood is more corrosive than CCA treated wood for every metal. The corrosion rate of aluminum was found to be lower than both hot-dip galvanized steel and electroplated galvanized steel in ACQ, ACA, and CCA treated wood. In ACA and ACQ treated wood, the electroplated galvanized fastener had a lower corrosion rate than the hot-dip galvanized fastener.

Keywords: Corrosion; Wood; Wood preservatives; Fastening.

Category: Journal Articles
File size: 2708 kb(s)

Abstract: Predicting the service life of building joint sealants exposed to service environments in less than real time has been a need of the sealant community for many decades. Despite extensive research efforts to design laboratory accelerated tests to duplicate the failure modes occurring in field exposures, little success has been achieved using conventional durability methodologies. In response to this urgent need, we have designed a laboratory-based test methodology that used a systematic approach to study, both independently and in combination, the major environmental factors that cause aging in building joint sealants. Changes in modulus, stiffness, and stress relaxation behavior were assessed. Field exposure was conducted in Gaithersburg, MD, using a thermally-driven exposure device with capabilities for monitoring changes in the sealant load and displacement. The results of both field and laboratory exposures are presented and discussed.

Keywords: Durability, Building joint sealants,elastomers,weatherproofing

Category: Journal Articles
File size: 264 kb(s)

Abstract: In order to quantify the effect of temperature on the mechanical properties of pure nylon 6 and its composite with cellulose fibers (containing 25wt% cellulose fibers), the materials were sampled and tested at three representative temperatures of 256, 296, and 336 K. Flexural and tensile tests were performed and the reductions in mechanical properties were evaluated. The highest reductions were observed in stiffness (modulus) values and the cellulose fibers remarkably enhanced the high temperature resistance of nylon. The reductions in mechanical properties were well explained by a simple quadratic curve fitting procedure applied to experimental data. Dynamic mechanical analysis (DMA) was also performed to study the effect of temperature on mechanical performance. No shifting in glass transition temperature was observed, but the composite material showed less viscous behavior as seen by its lower mechanical loss factor (tan 8) values in the rubbery state. The results of the present study will be helpful in determining the end-use application of these composite materials.

Keywords: composites, mechanical properties, temperature, nylon, cellulose.

Category: Journal Articles
File size: 2082 kb(s)

Abstract: Timber material repair and replacement cost for timber bridges is a considerable expense to highway agencies in Iowa, especially to county road departments. To address these needs, the objectives of this investigation was to study the field effectiveness of various treatment alternatives used on Iowa roadway projects and to determine if the current specifications and testing are adequate for providing proper wood preservation. To satisfy the research needs, the project scope involved a literature review, identification of metrics, questionnaire survey of Iowa counties, onsite inspections, and a review of current specifications and testing procedures. Based on the preservative information obtained, the following general conclusions were made: Copper naphthenate is recommended as the plant-applied preservative treatment for timber bridges. Best Management Practices should be followed to ensure quality treatment of timber materials. Bridge maintenance programs need to be developed and implemented. The Iowa Department of Transportation specifications for preservative treatment are the regulating specification for bridges constructed with state or federal funding in Iowa and are also recommended for all other bridges.

Keywords: preservatives specifications testing timber treatment wood

Category: Journal Articles
File size: 289 kb(s)

Abstract: Fire-resistive wood construction is achieved either by having the structural elements be part of fire-rated assemblies or by using elements of sufficient size that the elements themselves have the required fire-resistance ratings. For exposed structural wood elements, the ratings in the United States are calculated using either the T.T. Lie method or the National Design Specification (NDS®) for Wood Construction method. There is no widely accepted methodology in the United States to determine the fire-resistance rating of an individual structural wood element with the protective membrane directly applied to the exposed surfaces of the element. In these tests, we directly applied one or two layers of 5/8-inch-thick fire-rated gypsum board or 1/2inch-thick southern pine plywood for the protective membrane to the wood element. The wood elements were Douglas-fir laminated veneer lumber (LVL) specimens and Douglas-fir glued-laminated (glulam) timber specimens that had previously been tested without any protective membrane. The methodology for the tension testing in the horizontal furnace was the same used in the earlier tests. The fire exposure was ASTM E 119. For the seven single-layer gypsum board specimens, the improvements ranged from 25 to 40 minutes with an average value of 33 minutes. For the three double-layer specimens, the improvement in times ranged from 64 to 79 minutes with an average value of 72 minutes. We concluded that times of 30 minutes for a single layer of 5/8-inch Type X gypsum board and at least 60 minutes for a double layer of 5/8-inch Type X gypsum board can be added to the fire rating of an unprotected structural wood element to obtain the rating of the protected element.

Keywords: fire resistance, fire ratings, gypsum board, beams

Category: Journal Articles
File size: 191 kb(s)

Abstract: A pyranose 2-oxidase gene from the brown-rot basidiomycete Gloeophyllum trabeum was isolated using homology-based degenerate PCR. The gene structure was determined and compared to that of several pyranose 2-oxidases cloned from white-rot fungi. The G. trabeum pyranose 2-oxidase gene consists of 16 coding exons with canonical promoter CAAT and TATA elements in the 50UTR. The corresponding G. trabeum cDNA was cloned and contains an ORF of 1,962 base pairs encoding a 653 amino acid polypeptide with a predicted molecular weight of 72 kDa. A Hisx6 tagged recombinant G. trabeum pyranose 2-oxidase was generated and expressed heterologously in Escherichia coli yielding 15 U enzyme activity per ml of induced culture. Structural alignment and phylogenetic analysis were performed and are discussed.

Keywords: Genecloning, Gloeophyllum trabeum, Glucose oxidase, Pyranose 2-oxidase

Category: Journal Articles
File size: 383 kb(s)

Abstract: Trichodermareesei (teleomorph Hypocreajecorina) is a mesophilic soft-rot ascomycete fungus that is widely used in industry as a source of cellulases and hemicellulases for the hydrolysis of plant cell wall polysaccharides. For many years after its discovery during World War II, T.reesei was believed to reproduce asexually.However, although it was subsequently shown to be the anamorph of the pantropicala scomycete Hypocrea jecorina, the organism remains most widely recognized by its former name. It has enjoyed along history of safe use for industrial enzyme production and as an important model system for studying lignocellulose degradation.

Keywords: Trichoderma, Hypocrea, genome, cellulose

Category: Journal Articles
File size: 3576 kb(s)

Abstract: Southern blot and nucleotide sequence analysis of Phanerochaete chrysosporium BKM-F-1767 genomic clones indicate that this wood-degrading fungus contains at least six genes with significant homology to the Trichoderma reesei cellobiohydrolase I gene (cbh1). Using pulsed-field gel electrophoresis to separate P. chrysosporium chromosomes, the six cellulase genes were found to hybridize to at least three different chromosomes, one of which is dimorphic. The organization of these genes was similar in another P. chrysosporium strain, ME 446. It is clear that, unlike T. reesei, the most well-studied cellulolytic fungus, P. chrysosporium contains a complex, cbh1-like gene family.

Keywords: Genomic organization, cellulase gene family, Phanerochaete chrysosporium

Category: Journal Articles
File size: 268 kb(s)

Abstract: In order to quantify the effect of temperature on the mechanical properties of hemp fiber polypropylene composites, formulations containing 25% and 40% (by weight) hemp fiber were produced and tested at three representative temperatures of 256, 296, and 336 K. Flexural, tensile, and impact tests, as well as dynamic mechanical analysis, were performed and the reduction in mechanical properties were evaluated. Impact resistance was independent of temperature, whereas flexural and tensile properties were strongly affected. The highest reductions were observed in stiffness (modulus) values and flexural properties were reduced to a higher degree. The reductions in mechanical properties were well explained by a simple quadratic curve-fitting procedure applied to experimental data. Dynamic mechanical analysis revealed no change in glass transition temperature when the fiber content was increased but the composite material had better temperature resistance at higher fiber content. The results of the present study will be helpful in determining the end-use application of these composite materials.

Keywords: composites, mechanical properties, temperature, hemp fiber, polypropylene.

Category: Journal Articles
File size: 2297 kb(s)

Abstract: MOISTURE IS ARGUABLY THE MOST IMPORTANT factor affecting the performance and service life of wood and wood products. Moisture affects the dimensional movement of wood and wood products; under certain conditions, moisture change can result in major dimensional change. The integrity and strength of adhered (bonded) wood products can be compromised by swelling-induced stresses that accompany wetting. Progressive deflection over time of wood members under load is influenced by moisture conditions, particularly by large repetitive fluctuations in moisture content. Mechanical connections between wood members can be compromised by exposure to elevated moisture conditions or by significant moisture cycling. It is widely recognized that the structural integrity of wood can be irreversibly degraded by biological attack. In some cases biological infestation does not influence structural integrity but nevertheless influences serviceability. For many insect pests and all fungi, moisture conditions higher than the preferred inservice conditions are either required for infestation, or increase the likelihood of infestation.

Keywords: ASTM Manual chapter; moisture effects; conditions for decay; conditions for mold growth; conditions for insect infestation; dimensional movement; creep deflection; fastener performance

Category: Journal Articles
File size: 142 kb(s)

Abstract: The important attributes contributed to forest soils by organic matter make it imperative to determine the quantity and type required to sustain good forest tree growth. Quantitative measurement of soil humus, decayed wood, and charcoal as related to numbers of active ectomycorrhizal root tips (in random soil cores from old-growth sites in western Montana) showed both positive and negative relationships with organic matter. Increased quantities of organic material, to 45 percent by volume of the top 30 cm of soil, were associated with increased numbers of ectomycorrhizae. At 45 percent organic matter or above, numbers of ectomycorrhizae decreased. Study results also showed association with soil organic matter had a relatively greater positive effect on ectomycorrhizae of the dry site than the moist sites.

Keywords: Woody residues, fuels, forest fire, soil quality, fungi, decomposition products, soil organic matter

Category: Journal Articles
File size: 813 kb(s)

Abstract: Many litter-decay fungi secrete heme-thiolate peroxygenases that oxidize various organic chemicals, but little is known about the role or mechanism of these enzymes. We found that the extracellular peroxygenase of Agrocybe aegerita catalyzed the H2O2-dependent cleavage of environmentally significant ethers, including methyl t-butyl ether, tetrahydrofuran, and 1,4- dioxane. Experiments with tetrahydrofuran showed the reaction was a two-electron oxidation that generated one aldehyde group and one alcohol group, yielding the ring-opened product 4-hydroxybutanal.

Keywords: Ethers, Biodegradation, Lignin, Cytochrome P450, Chloroperoxidase

Category: Journal Articles
File size: 368 kb(s)

Abstract: This paper summarizes recent laboratory and field data studies on thermal performance of stress-laminated timber highway bridges. Concerns about the reliability of stress-laminated deck bridges when exposed to sub-freezing temperatures triggered several investigations. Two laboratory studies were conducted to study the effects of wood species, preservative, moisture content, and temperature variations on pre-stressing bar forces (critical factor) in stress-laminated decks. The field performance of several stress-laminated timber bridges were monitored within a Nationwide Timber Bridge Monitoring Program, a cooperative effort by the U.S. Forest Service, Forest Products Laboratory and Federal Highway Administration. Bar-force and temperature data from a subset of bridges were continuously monitored for a period of 2 to 5 years with remote data acquisition systems. Significant prestressing bar-force losses were observed in laboratory studies when the moisture content of deck laminations were at 30 percent and greater and the deck temperature reached 0°F (-18°C) and below. The field study concluded that the magnitude of cold-temperature induced bar-force losses were not significant enough to warrant special considerations in the U.S. bridge design code. However, it may warrant special considerations in cold weather regions outside the United States whenever deck lamination moisture contents exceeding 20 percent are combined with ambient temperatures remaining below 0°F (-18°C) for extended periods of time.

Keywords: timber, bridge, stress-laminated, cold temperatures, prestress, bar force

Category: Journal Articles
File size: 434 kb(s)

Abstract: Genome sequencing and subsequent global gene expression studies have advanced our understanding of the lignocellulose-fermenting yeast Pichia stipitis. These studies have provided an insight into its central carbon metabolism, and analysis of its genome has revealed numerous functional gene clusters and tandem repeats. Specialized physiological traits are often the result of several gene products acting together. When coinheritance is necessary for the overall physiological function, recombination and selection favor colocation of these genes in a cluster. These are particularly evident in strongly conserved and idiomatic traits. In some cases, the functional clusters consist of multiple gene families. Phylogenetic analyses of the members in each family show that once formed, functional clusters undergo duplication and differentiation. Genome-wide expression analysis reveals that regulatory patterns of clusters are similar after they have duplicated and that the expression profiles evolve along with functional differentiation of the clusters. Orthologous gene families appear to arise through tandem gene duplication, followed by differentiation in the regulatory and coding regions of the gene. Genome-wide expression analysis combined with cross-species comparisons of functional gene clusters should reveal many more aspects of eukaryotic physiology.

Keywords: yeast; evolution; genome; tandem repeats; orthologs; expression arrays.

Category: Journal Articles
File size: 945 kb(s)

Abstract: Timber can often be a cost-effective construction material for new bridges. The durability of the bridge greatly depends on proper attention to construction details and fabrication, as well as proper preservative treatment before, during, and after construction. Material repair and replacement costs for bridges are a considerable expense for highway agencies. To address these needs, the objectives of an investigation were to determine the field effectiveness of various treatment alternatives used on Iowa roadway projects and to provide information on preservative treatments, inspection techniques, and current specifications for bridge owners. Special emphasis was placed on providing up-to-date synthesized information for county engineers to maintain their timber bridge inventory more effectively. The project scope included a literature review, identification of testing techniques, on-site inspections of bridges in Iowa, and a review of current specifications and testing procedures. On the basis of information evaluated, these general conclusions were made: copper naphthenate was recommended as the plant-applied preservative treatment for timber bridges, American Wood Protection Association Standards and Best Management Practices should be followed to ensure high-quality treatment of timber materials, and bridge maintenance programs would be enhanced by the development of an effective construction and remedial treatment process to improve bridge durability.

Keywords: Category IIIC, preservation treatment, wood bridge application

Category: Journal Articles
File size: 274 kb(s)

Abstract: Laccase is one of the ligninolytic enzymes found in liquid of the fungus Ceriporiopsis subvermispora in defined medium. As an approach to a clarification of the role of laccases during the attack on lignin by the fungus, the enzyme has been characterized further. The levels of this phenol oxidase increase 2-fold in the presence of p-anisidine and are severely affected when addition of either Mn(II) or Cu(II) ions to the medium is omitted. Isoelectrofocusing allowed the resolution of two laccase isoenzymes, with pIS of 3.65 and 3.59. In rich medium, laccase activity is 10-fold higher than in salt medium, and it is not affected by the external addition of p-anisidine or Four isoenzymes were detected in these cultures, with pIS between 3.76 and 3.60. In a wheat bran medium, four isoenzymes with pIS in the range 3.63-3.46, plus a fifth isoenzyme of high pI (4.82), were also identified. The absorption spectrum of a pool containing the four isoenzymes from rich medium shows a maximum at 600 nm, typical of laccase possessing a type I copper atom. The molecular mass of the isoenzyme with pI 3.60 is 79 kDa, as determined by SDS/PAGE. Upon treatment with endoglycosidase F, the molecular mass of this isoform decreases to 63 kDa, indicating a high degree of glycosylation. Substrate specificity studies conducted with the four isoenzymes from rich medium and a combination of isoenzymes from salt medium showed marked differences among them. The amino-terminal sequences (24 residues) of three isoenzymes isolated from rich medium were determined. Two of them are identical, whereas the third one differs from these in three amino acid residues. The consensus sequence reveals clear homology with laccases from other microorganisms.

Keywords: laccase, Ceriporiopsis, lignin

Category: Journal Articles
File size: 727 kb(s)

Abstract: The presented work reports the isolation and heterologous expression of the p2ox gene encoding the flavoprotein pyranose 2-oxidase (P2Ox) from the basidiomycete Phanerochaete chrysosporium. The p2ox cDNAwas insertedinto the bacterial expression vector pET21a(+) and successfully expressed in Escherichia coli.We obtained active, fully flavinylated recombinant P2Ox in yields of approximately 270 mg/lmedium. The recombinant enzyme was provided with an N-terminal T7-tag and a C-terminal His6-tag to facilitate simple one-step purification.We obtained an apparently homogenous enzyme preparation with a specific activity of 16.5 U/mg. Recombinant P2Ox from P. chrysosporium was characterized in some detail with respect to its physical and catalytic properties, both for electron donor (sugar substrates) and - for the first time - alternative electron acceptors (1,4-benzoquinone, substituted quinones, 2,6-dichloroindophenol and ferricenium ion). As judged from the catalytic efficiencies k_cat/K_m, some of these alternative electron acceptors are better substrates than oxygen, which might have implications for the proposed in vivo function of pyranose 2-oxidase.

Keywords: Pyranose 2-oxidase, Phanerochaete chrysosporium, Lignocellulose degradation, Heterologous expression

Category: Journal Articles
File size: 85 kb(s)

Abstract: Recycling of fiber into structural papers for the corrugated container industry, paper tubes, cartonboard or other paperboard with structural performance needs may require enhancement of properties through changes in the papermaking process. The loss of bonding capability, coupled with a degree of fiber shortening and fiber inflexibility, reduces the utility of recycled fiber and thus their competitiveness with their virgin counterparts, Traditional means for enhancing performance includes addition of starches or other binders, mechanical beating, or heat treatments. Other means for achieving heightened performances are reviewed which include alternative drying technologies, optimal placement of fibers within the paper sheet and forming technologies that provide structural enhancement.

Keywords: Fibers, fractionation, swelling, drying methods, fiber bonding,fiber alignment, pulp molding

Category: Journal Articles
File size: 838 kb(s)

Abstract: Wood has several levels of hierarchical structure, spanning from the configuration of growth-rings down to the configuration of the base polymers (cellulose, hemicellulose, and lignin). The bulk properties of wood result from the culmination of interactions over all length scales. Gaps presently exist in the fundamental knowledge relating the contribution of wood properties at each structural level to the resulting bulk properties. The advent of nanoindentation has facilitated mechanical property measurement at the cell wall layer; however, there is limited understanding of how and to what extent the properties at the cell wall level influence the bulk properties.

Keywords: Nanoindentation, Macroindentation, hardness, Hierarchical structure, radiata pine (Pinus radiata)

Category: Journal Articles
File size: 1059 kb(s)

Abstract: The Asperqillus nidulans sequence ans1, previously known to enhance transformation frequencies of pyr4-based vectors, was shown to enhance the efficiency of argB and trpC-based vectors. Increased efficiencies could be obtained by constructing vectors containing argB and ans1 or by cotransforming selectable plasmids (containing argB, trpC or pyr4) with the non-selectable ans1 sequence. The preponderance of evidence suggests that the mechanism of ans1 activity does not involve homologous recombination events, in spite of the presence of multiple regions of homology in the A. nidulans genome. Genetic mapping localized ans1 to the vicinity of the centromere of linkage group I. The nucleotide sequence of a 1.8 Kb functional subclone of ans1 was determined and found to be highly A+T rich (81%).

Keywords: ans1, Aspergillus nidulans, centromere proximal location, Sequence

Category: Journal Articles
File size: 104 kb(s)

Abstract: We have developed a novel type of nanoindentation creep experiment, called broadband nanoindentation creep (BNC), and used it to characterize the thermal activation of shear transformation zones (STZs) in three BMGs in the Zr-Cu-Al system. Using BNC, material hardness can be determined across a wide range of strain rates (10^-4 to 10 s^-1) in a single experiment at room temperature.

Keywords: Nanoindentation creep, thermally-activated deformation, bulk metallic glass

Category: Journal Articles
File size: 310 kb(s)

Abstract: Response surface methodology was used to evaluate optimal time, temperature and oxalic acid concentration for simultaneous saccharification and fermentation (SSF) of corncob particles by Pichia stipitis CBS 6054. Fifteen different conditions for pretreatment were examined in a 23 full factorial design with six axial points. Temperatures ranged from 132 to 180 °C, time from 10 to 90 min and oxalic acid loadings from 0.01 to 0.038 g/g solids. Separate maxima were found for enzymatic saccharification and hemicellulose fermentation, respectively, with the condition for maximum saccharification being significantly more severe. Ethanol production was affected by reaction temperature more than by oxalic acid and reaction time over the ranges examined. The effect of reaction temperature was significant at a 95% confidence level in its effect on ethanol production. Oxalic acid and reaction time were statistically significant at the 90% level. The highest ethanol concentration (20 g/l) was obtained after 48 h with an ethanol volumetric production rate of 0.42 g ethanol l¹ h¹. The ethanol yield after SSF with P. stipitis was significantly higher than predicted by sequential saccharification and fermentation of substrate pretreated under the same condition. This was attributed to the secretion of B-glucosidase by P. stipitis. During SSF, free extracellular b-glucosidase activity was 1.30 pNPG U/g with P. stipitis, while saccharification without the yeast was 0.66 pNPG U/g.

Keywords: Optimization; Pichia stipitis; Cellulase; SSF; ?-Glucosidase

Category: Journal Articles
File size: 510 kb(s)

Abstract: Restriction mapping and sequence analysis of cosmid clones revealed a cluster of three cellobiohydrolase genes in Phanerochaete chrysosporium. P. chrysosporium cbh1-1 and cbh1-2 are separated by only 750 bp and are located approximately 14 kb upstream from a cellulase gene previously cloned from P. chrysosporium (P. Sims, C. James, and P. Broda, Gene 74:411422, 1988). Within a well-conserved region, the deduced amino acid sequences of P. chrysosporium cbh1-1 and cbh1-2 are, respectively, 80 and 69% homologous to that of the Trichoderma reesei cellobiohydrolase I gene. The conserved cellulose-binding domain typical of microbial cellulases is absent from cbh1-1. Transcript levels of the three P. chrysosporium genes varied substantially, depending on culture conditions. cbh1-1 and cbh1-2 were not induced in the presence of cellulose, nor did they appear to be subject to glucose repression. Therefore, aspects of the chromosomal organization, structure, and transcription of these genes are unlike those of any previously described cellulase genes.

Keywords: Structure, organization, transcription, Cellobiohydrolase gene, Phanerochaete chrysosporium

Category: Journal Articles
File size: 4306 kb(s)

Abstract: Few building materials possess the environmental benefits of wood. It is not only the most widely used building material in the United States but also one with characteristics that make it suitable for a wide range of applications. Efficient, durable, and useful wood products produced from trees range from a minimally processed log at a log-home building site to a highly processed and highly engineered wood composite manufactured in a large production facility.

Keywords: wood, green building materials, sustainability, embodied energy, carbon footprint, sustainable forestry, green building

Category: Research Notes
File size: 236 kb(s)

Abstract: When a basic rigid epoxy adhesive was modified with an elastomer to provide some degree of stress relief, wood butt joints bonded with the resulting ductile adhesive were significantly stronger than joints with the unmodified adhesive (3) .4- The effect of adhesive age, as a measure of adhesive viscosity, on joint strength was even more significant than the influence of adhesive formulation. Age of adhesive was measured as time elapsed after the curing agent was added to the adhesive mix and before it was applied to the bonding surfaces.

Keywords: end-whale bonding, Lumen Bonding, butt joints, strength

Category: Research Notes
File size: 1219 kb(s)

Abstract: The value of some northeastern tree species could be increased if they could be adequately treated with preservatives and shown to be durable in outdoor exposures. This paper reports on research to evaluate the ground-contact durability of northeastern species treated with copper-based preservatives. Stakes (19 by 19 by 457 mm) cut from balsam fir, eastern hemlock, eastern spruce, white pine, or red maple were treated with one of four concentrations of chromated copper arsenate, copper citrate, alkaline copper quat, or copper azole and placed into the ground at a test site in southern Mississippi. Similarly treated Southern Pine stakes were included for comparison. For 5 years, the stakes were rated annually for decay and termite attack. Untreated stakes of all wood species failed rapidly, indicating that none of the species evaluated have significant natural durability. Occasional failures have occurred in treated stakes, typically at the lower preservative retentions. Treated Southern Pine and eastern hemlock stakes have experienced the fewest failures, with treated white pine stakes performing nearly as well. Treated eastern spruce and red maple stakes had the most failures, and treated balsam fir stakes also had substantial failures. The failures in eastern spruce and balsam fir stakes appear to be attributable to poor preservative penetration and retention within individual stakes. Failures in the red maple stakes may be attributable to the differences in hardwood anatomy and the distribution of preservative within the wood structure. Of the northeastern species evaluated, eastern hemlock and white pine appear to perform most similarly to Southern Pine when treated with the copper-based preservatives. However, further exposure time is needed to allow more definitive conclusions.

Keywords: Northeastern species; copper-based preservatives; stake tests; durability

Category: Research Papers
File size: 1008 kb(s)

Abstract: Since fire-retardant-treated wood is gaining more acceptance year by year, it is desirable that its strength properties be known, particularly far structural applications. This paper summarizes the results of several studies conducted at the Forest Products Laboratory and elsewhere on the bending properties of air-dried and kiln-dried fire-retardant-treated wood. Collectively the studies indicate that modulus of rupture and work to maximum load in bending were reduced by varying amounts depending on species and type of fire retardant. In general, the reductions are consistent with the 10 percent reduction in design stresses recommended for fire-retardant-treated lumber.

Keywords: Fire-retardant Treatment, Bending strength, MIL-L-19140C

Category: Research Papers
File size: 724 kb(s)

Abstract: This Paper presents the modulus of elasticity and strength values of four reinforced plastic laminates in tension and compression at room temperature and at 500° F. Prior to evaluation at these temperatures, the test specimens were exposed to thermal-shock cycling. Three of the laminates evaluated in this study were reinforced with 181-A1100 glass and represented three resin systems: a phenolic resin (CTL 37-9X), an epoxy resin (ERSB-0111), and a phenyl-silane (Narmco 534). The fourth was a phenolic-asbestos laminate made of R/M Pyrotex felt style 41-RPD.

Keywords: reinforced plastic laminates, thermal-shock cycling, compressive strength, tensile strength

Category: Research Papers
File size: 1708 kb(s)

Abstract: Three fairly abundant western softwoods were combined in mixture for pulping and bleaching experi-ments to determine their suitability for pulps of three types--groundwood, kraft, and viscose-grade sulfite. A good-quality groundwood pulp, suitable for news-print, production, was obtained from a mixture of 65 percent Engelmann spruce and equal parts of subalpine fir and lodgepole pine. The groundwood pulp responded well to peroxide and hydrosulfite bleaching. The kraft pulp made from this same softwood mixture had a yield of 46.3 percent and a permanganate number of 19.5, and its strength was in the high range of kraft pulps. In bleaching, a brightness as high as 91 percent was obtained. The viscose-grade sulfite pulp compared favorablyin the usual test values with those published for pulps, Its alpha-cellulose content was 95 percent, and the yield was high--40 percent.

Keywords: Englemann Spruce, Subalpine Fir, Lodgepole Pine, Bleached Groundwood, Kraft, Sulfiet viscose-grade Pulp

Category: Research Papers
File size: 824 kb(s)

Abstract: The coefficients of thermal conductivity for mean temperatures ranging from about -300° to +500° F. were determined for nine combinations of asbestos fiber or glass fiber and cloth reinforcement, with epoxy, phenolic, silicone, phenyl silane, and epoxy-novalac resins. Values of conductivity are only valid to maximum mean temperatures between +300° and 350° F. (depending on resin) because of thermal degradation of the plastic due to 'hot-side' temperatures in excess of mean temperature.

Keywords: Aircraft, glass, asbestos, fiber-reinforced

Category: Research In Progress
File size: 782 kb(s)

Abstract: Seismic design of buildings is based on a combination of empirical knowledge and engineering analysis. The experience accumulated from seismic events and large-scale tests provides confidence in engineering models and serves to establish acceptable levels of risk for code compliance (Figure 1). With the ongoing development of new building systems, accumulated experience and testing is lacking to establish acceptable risk levels for these systems. To address this need, the Federal Emergency Management Agency (FEMA) developed FEMA P695 (ATC-63), a methodology for quantifying building system performance and response parameters for use in seismic design.

Keywords: seismic design; light frame wood construction; nonlinear analysis; modeling; FEMA

Category: General Technical Reports
File size: 2000 kb(s)

Abstract: The framework of ASTM D 1990 has been used numerous times to determine design values for development of imported and domestic species since ASTM D 1990 was first utilized in 1991 to determine allowable properties for the major commercial species in North America. The interpretations of this standard and judgments applied to these submissions are described in this report. The major issues that have been sources of controversy in D 1990 are also summarized.

Keywords: American Lumber Stancard Committee; In-Grade Testing; Foreign Species Submissions; Design Value Calculations

Category: FPL News
File size: 145 kb(s)

Abstract: 

Category: NewsLine
File size: 990 kb(s)

Abstract: 

Forest Owners and Carbon Markets:Can't We All Just Get Along?
Upcoming Events
Wood You Believe
Celebrating a Century of Innovation Forest Products Laboratory, 1910-2010
Ask FPL
U.S. Forest Service and College of Menominee Nation Sign Partnership Agreement


Keywords: forest owners and carbon markets, upcoming events, wood you believe, celebrating a century of innovation, forest products laboratory 1910-2010, ask fpl, college of menominee nation sign partnership agreement

Category: Journal Articles
File size: 1030 kb(s)

Abstract: Cellulose nanocrystals (CNCs) are gaining interest as a 'green' nanomaterial with superior mechanical and chemical properties for high-performance nanocomposite materials; however, there is a lack of accurate material property characterization of individual CNCs. Here, a detailed study of the topography, elastic and adhesive properties of individual wood-derived CNCs is performed using atomic force microscopy (AFM). AFM experiments involving high-resolution dynamic mode imaging and jump-mode measurements were performed on individual CNCs under ambient conditions with 30% relative humidity (RH) and under a N2 atmosphere with 0.1% RH. A procedure was also developed to calculate the CNC transverse elastic modulus (ET) by comparing the experimental force-distance curves measured on the CNCs with 3D finite element calculations of tip indentation on the CNC. The ET of an isolated CNC was estimated to be between 18 and 50 GPa at 0.1% RH; however, the associated crystallographic orientation of the CNC could not be determined. CNC properties were reasonably uniform along the entire CNC length, despite variations along the axis of 3-8 nm in CNC height. The range of RH used in this study was found to have a minimal effect on the CNC geometry, confirming the resistance of the cellulose crystals to water penetration. CNC flexibility was also investigated by using the AFM tip as a nanomanipulator.

Category: Research In Progress
File size: 1265 kb(s)

Abstract: Forests in the United States contain a substantial amount of small-diameter material from underutilized tree species. Overstocked stands of trees need to be thinned to help reduce the risks of wildfire and improve overall forest health, but they often have relatively low value because of trunk size, growth habitat, accessibility, or lack of commercial applications. Other introduced tree species have invaded natural ecosystems and reduced biological diversity in native flora and wildlife. Some of these underutilized and invasive wood species are known to be naturally resistant to insects and decay, but relatively little is known about the field performance of wood products from these species or the physical or chemical properties that impart their natural durability. New applications for wood from these species would enhance the cost effectiveness of thinning operations, create business and employment opportunities in rural communities, and increase options for replacement components in residential and non-residential structures while reducing wildfire risks and improving forest health.

Keywords: Molecular genetics; Terminal Restriction Fragment Length Polymorphism (TRFLP); microbial succession; above-ground; natural durability; invasive species; underutilized species

Category: Research In Progress
File size: 235 kb(s)

Abstract: The shift from traditional forest management to ecosystem restoration practices is expected to generate a sustainable flow of small-diameter logs that could be used to produce structural and nonstructural building products. Conversion of these raw materials to the most appropriate end uses is vital to restoration management and the local industries it supports.

Keywords: douglas-fir; lumber; stiffness; ecosystem restoration; small diameter

Category: Journal Articles
File size: 212 kb(s)

Abstract: The photochemical resistance of polymers can be improved greatly by using grafted photostabilisers. This method was used here to improve the photostability of wood and the performance of clear coatings on wood. Reactive UV absorbers (UVAs), including 2-hydroxy-4(2,3-epoxypropoxy) benzophenone (HEPBP) and some epoxy-functionalised triazine-type UVAs, were synthesised and the reaction conditions required to graft UVAs on to wood were examined. Grafting of reactive UVAs was more effective than UVA treatments without grafting or than chromium trioxide modification for restricting losses in weight and tensile strength of thin wood veneers during weathering. Grafting UVAs on to wood reduced photochemical changes at exposed wood surfaces and greatly improved the performance of clear coatings on modified veneer surfaces.

Category: Forest Products Utilization Technical Reports
File size: 2283 kb(s)

Abstract: This report presents data on the edgewise compressive strength of short columns of flat sandwich plates. It contains the results of a limited number of tests that were made on sandwich constructions to determine the failing stress of the facing material. This report also presents some mechanical properties of the core and facing materials used in the sandwich plates, and describes the methods employed to obtain then.

Keywords: strength, Flat Sandwich plates, edgewise compression

Category: General Technical Reports
File size: 309 kb(s)

Abstract: This assessment characterizes, at a regional scale, forest biomass that can potentially be removed to implement the fuel reduction and ecosystem restoration objectives of the National Fire Plan for the Western United States. The assessment area covers forests on both public and private ownerships in the region and describes all standing tree volume including stems, limbs, and tops. Analysis of treatment areas and potential removals is included. Additionally, the operational systems necessary to effect the treatments as well as potential erosion impacts, utilization opportunities and market implications were examined.

Keywords: assessment, biomass, fuel reduction, inventory

Category: General Technical Reports
File size: 2810 kb(s)

Abstract: Because of the potential risk associated with moving firewood infested with emerald ash borer, the interstate movement of all hardwood firewood is currently restricted under Federal quarantine. Communities and firewood producers are now faced with decisions on how to treat firewood for interstate commerce. New regulations for heat sterilization of ash firewood require holding a core temperature of 160^°F for 75 min, much higher than the current international heating standard for treating solid wood packaging. The present study evaluated different heat-treatment options for various firewood operations and developed heat-treating schedules and heating time tables. We first conducted laboratory heating experiments using green and air-dried ash firewood and obtained heating time data for different heating schemes. Mathematical models were developed to estimate heating times for heating conditions not tested in the experiment. Heating time tables were developed for a series of heating temperatures and initial wood temperatures. Our field heat-treatment trial in a commercial dry-kiln facility indicated a significant difference in heating times between the laboratory kiln runs and the field kiln run. Although the size of kiln could have contributed to the increase of heating times in the field trial, the type of kiln and heat sources are the main factors that control the heating rate and result in differences in heating times. More field heat-treatment trials at different types of kiln facilities (steam, hot water, and direct fire) should be conducted in the future to calibrate the heating time tables developed through the laboratory experiments.movement of all hardwood firewood is currently restricted under Federal quarantine. Communities and firewood producers are now faced with decisions on how to treat firewood for interstate commerce. New regulations for heat sterilization of ash firewood require holding a core temperature of 160 °F for 75 min, much higher than the current international heating standard for treating solid wood packaging. The present study evaluated different heat-treatment options for various firewood operations and developed heat-treating schedules and heating time tables. We first conducted laboratory heating experiments using green and air-dried ash firewood and obtained heating time data for different heating schemes. Mathematical models were developed to estimate heating times for heating conditions not tested in the experiment. Heating time tables were developed for a series of heating temperatures and initial wood temperatures. Our field heat-treatment trial in a commercial dry-kiln facility indicated a significant difference in heating times between the laboratory kiln runs and the field kiln run. Although the size of kiln could have contributed to the increase of heating times in the field trial, the type of kiln and heat sources are the main factors that control the heating rate and result in differences in heating times. More field heat-treatment trials at different types of kiln facilities (steam, hot water, and direct fire) should be conducted in the future to calibrate the heating time tables developed through the laboratory experiments.

Keywords: ash firewood; emerald ash borer (EAB); heat treatment; dry heat; wet heat

Category: Journal Articles
File size: 13357 kb(s)

Abstract: The measurement of effective residual ink concentration (ERIC) in recycled papers is prone to errors. TAPPI Provisional Method T 567 pm-97 is based on application of the Kubelka Munk (KM) theory to diffuse reflection from papers measured once with the black backing and again with a thick backing of the same papers. At high opacities the two results become indistinguishable, leading to an undetermined value for ERIC when the full KM theory is applied. This is handled by use of an approximate value for the KM scattering coefficient to remove the ambiguity. However, the approximate value may be in error by 10%. An alternate approach avoids the uncertainty inherent in the approximation by applying the KM theory to the measurement of diffuse reflection and transmission in single sheets. The measurement is valid at any opacity for which the percentage transmission through the sheet is accurately determined in the near-infrared spectral region. Coefficients of variation (COV) are as low as or lower than those from the standard ERIC measurement throughout the range of interest. They decrease with increasing opacity to a low of 8% for a sheet having 1000 ppm ERIC, compared to a COV of 16% for the standard measurement based on an average value of scattering coefficient. The proposed method promises to be a superior way to monitor deinking in recycled papers.

Keywords: residual ink concentration, deinked papers, approach to measurement

Category: Journal Articles
File size: 199 kb(s)

Abstract: Acid pretreatment of wood provides significant energy savings during refining but reduces the brightness of the pulp. Acid treatments also extract carbohydrates from wood. Addition of an acid pretreatment process to a thermomechanical pulping process therefore offers an opportunity to reduce refining energy cost and provide a secondary product from a fermentation ethanol plant. A process being investigated by BioPulping International and the Forest Products Laboratory involves pretreatment with oxalic acid or diethyl oxalate and offers 25% or more reduction in specific refiner energy consumption, with a minor sacrifice in brightness. This treatment also results in extraction of approximately 6% of the wood mass. Similarly, research during the late 1970s on sulfonated chemimechanical pulping at low pH determined that bisulfite reduced specific refining energy, maintained brightness, and released carbohydrates. The similarity in behavior of these two pretreatments suggests a common mechanism that is the subject of this study. Our hypothesis is that both acids provide optimal conditions, either buffering at pH 2 or mildly reducing conditions, for pretreating wood. To test this hypothesis, a series of spruce and aspen veneer samples were pretreated with sodium bisulfate, sulfurous acid, and oxalic acid. These three acids can provide buffering near pH 2 and a range of redox potential. The wood chip brightness of the sodium bisulfate and oxalic acid experiments were similar but at a given yield sulfurous acid seems to preserve brightness better than does either bisulfate or oxalic acid. The redox activity does not seem to affect results.

Keywords: acid prehydrolysis, energy savings,sodium bisulfate, sulfurous acid, oxalic acid

Category: Journal Articles
File size: 149 kb(s)

Abstract: Accurate determination of corrosion rates for threaded fasteners hinges on the ability to determine the surface area on which corrosion is occurring. Currently, no general analytical expression of surface area exists for the threaded fastener types. A recent voluntary withdrawal of chromated copper arsenate as the primary, long-standing preservative treatment for wood resulted in the need to determine the corrosion rates of threaded fasteners. This paper developed general analytical surface area equations for a wedge-shaped thread and the area between the threads for three cases: (1) an increasing thread root and crest diameter, (2) constant thread root and crest diameters, and (3) a constant thread root but a decreasing thread crest diameter. The expressions are applied, numerically verified, and compared to simplified models for a No. 10-2.54 cm (1-in.) long wood screw.

Keywords: corrosion, analytical, fastener, screw, surface area

Category: Journal Articles
File size: 1213 kb(s)

Abstract: Veratryl alcohol (VA) is a secondary metabolite of white-rot fungi that produce the ligninolytic enzyme lignin peroxidase. VA stabilizes lignin peroxidase, promotes the ability of this enzyme to oxidize a variety of physiological substrates, and is accordingly thought to play a significant role in fungal ligninolysis. Pulse-labeling and isotope-trapping experiments have now clarified the pathway for VA biosynthesis in the white-rot basidiomycete Phanerochaete chrysosporium. The pulse-labeling data, obtained with ¹⁴C-labeled phenylalanine, cinnamic acid, benzoic acid, and benzaldehyde, showed that radiocarbon labeling followed a reproducible sequence: it peaked first in cinnamate, then in benzoate and benzaldehyde, and finally in VA. Phenylalanine, cinnamate, benzoate, and benzaldehyde were all efficient precursors of VA in vivo. The isotope-trapping experiments showed that exogenous, unlabeled benzoate and benzaldehyde were effective traps of phenylalanine-derived ¹⁴C. These results support a pathway in which VA biosynthesis proceeds as follows: phenylalanine --> cinnamate -> benzoate and/or benzaldehyde --> VA.

Keywords: biosynthetic pathway, veratryl alcohol, phanerochaete chrysosporium

Category: Journal Articles
File size: 433 kb(s)

Abstract: Scanning probe microscopy (SPM) techniques have been used to investigate cellulose nanocrystal (CNC) surface chemistry and mechanical properties. Atomic force microscopy (AFM) was used to measure topography, stiffness, and pull-off force of CNC surfaces exposed to N₂ tmosphere with a 0.1% relative humidity (RH). Changes in the stiffness and pull-off force as a function of location long CNC surfaces were used to assess the uniformity in mechanical properties and surface chemistry, respectively. This work showed that the contact geometry affected all measurements and needs to be accounted for in the data analysis. Qualitatively, after taking into consideration effects of contact geometry, we find that the stiffness and pull-off force were reasonably uniform across the CNC length.

Keywords: atomic force microscopy, cellulose nanocrystals, relative humidity, topography, stiffness, pull-off force

Category: Journal Articles
File size: 82 kb(s)

Abstract: Covered wooden bridges once dotted the landscape of the United States numbering 14,000 at one time as reported in the Federal Highway Administration's Covered Bridge Manual [1]. Today there are only 500 to 600 covered bridges remaining in the country, having survived hundreds of years largely as result of the roof structure which kept the bridge timbers dry. This paper reports on select number of existing covered bridges and current efforts to preserve and restore these historic structures. It provides an overview of the National Historic Covered Bridge Preservation (NHCBP) Program administered by the Federal Highway Administration. This program includes preservation of covered bridges that are listed, or are eligible for listing on the National Register of Historic Places. It also includes research for better means of restoring and protecting covered bridges, and includes education component to disseminate information as a means of preserving our cultural heritage.

Keywords: Covered bridges, United States, Preservation program

Category: Journal Articles
File size: 668 kb(s)

Abstract: Pressure sensitive adhesive (PSA) contaminates post consumer waste impeding its processing and limiting the use of recovered cellulose fiber. An approach for reducing the impact of PSA on recycling operations is to redesign label systems to inhibit fragmentation of adhesive films. This results in residual PSA particles that are more easily removed from the process with conventional mill contaminant control equipment. In this presentation findings are reviewed from research aimed at the development of adhesive films that have little or no negative impact on recycling operations. Both hot-melt and water- based formulations were examined, which combined, account for much of the PSA paper label market. For both types of PSAs, properties of the base polymer or polymer blend govern, to a great extent, fragmentation behavior during processing, but via very different mechanisms. Also discussed will be the role of laminate design and processing aids in determining the fragmentation behavior of adhesive films.

Keywords: design criteria, recycling, compatable pressure-sensitive products

Category: Journal Articles
File size: 310 kb(s)

Abstract: Several changes relating to timber bridges have been incorporated into the AASHTO-LRFD Bridge Design Specifications recently. In addition, the Federal Highway Administration is strongly encouraging an LRFD-based design approach for all new bridges in the United States. The Bridge Design Code in Canada was one of the first to adopt the limit states design philosophy, doing so many years ago. This paper presents an overview of the United States and Canadian bridge design codes, highlighting similarities and differences that relate to the design of timber bridges.

Keywords: Timber bridge superstructures, bridge codes, US, Canada

Category: Journal Articles
File size: 64 kb(s)

Abstract: In the natural ecosystem, wood residues are recycled into the nutrient web through the action of wood-degrading fungi, insects, and other organisms. In some circumstances. these same natural recyclers have the potential to degrade wood used in construction. Termites and decay fungi are the most destructive, but other organisms, such as wood boring beetles and carpenter ants, can be important in Some regions. Several types of marine organisms can attack wood used in brackish water and saltwater. If conditions are favorable for the survival of one or more of these wood-destroying organisms, wood that has natural durability or that has been treated with preservatives should be employed to ensure the integrity of the structure.

Keywords: biodeterioration, fire, treated wood, preservative treatments, naturally durable

Category: Journal Articles
File size: 135 kb(s)

Abstract: This paper discusses the effects of size and moisture content on stress wave properties of wood and evaluates the feasibility of using stress waves to E-rate Douglas-fir dimension lumber in green condition. Six size groups of Douglas-fir lumber were tested using both stress wave and static bending methods at different moisture levels, ranging from green to dry conditions. Stress wave speed increased continuously as moisture content decreased through the whole moisture range studied. General speedmoisture relationships were developed to adjust stress wave speed values from one moisture condition to any other moisture conditions. It was found that stress wave based dynamic modulus of elasticity (MOE) is generally higher than static bending MOE. However, the difference tends to be constant when moisture content is above fiber saturation point. This suggests that green lumber can be sorted effectively based on dynamic MOE values even if there are moisture differences between individual pieces.

Keywords: Structural lumber, stress waves, E-rating, modulus of elasticity, moisture content, size

Category: Journal Articles
File size: 293 kb(s)

Abstract: Many timber trestle railroad bridges in Wisconsin have experienced deterioration and are in need of rehabilitation. In addition, the railroad industry is increasing the weights of cars. The combined effect of heavier loads and deterioration threatens to cut short the service life of timber bridges. One of the most critical problems that has been identified was the overloading of timber piles in bridges, which can be remedied by creating a stiffer pile cap. The goal of this investigation was to show that fiber reinforced polymer (FRP) strips fastened to timber with screws can be used to create composite action between two beams in flexure or truss action between two deep beams. Ultimately this may help redistribute the loads to piles when FRP strips are used as struts on cap beams over short spans. Several test series were conducted with beams in flexure, deep beams over short spans, and full scale specimens to determine the manner in which FRP strips improved the members' performance. Mechanically fastened FRP strips were effective in developing composite action in slender beams in flexure and truss action in short deep beams.

Keywords: Rehabilitating timber bridges, mechanically fastened FRP strips

Category: Journal Articles
File size: 214 kb(s)

Abstract: Associations between plant roots and fungi are a feature of many terrestrial ecosystems. The genome sequence of a prominent fungal partner opens new avenues for studying such mycorrhizal interactions.

Keywords: fungus, symbiosis, mycorrhizal interaction, genome sequencing

Category: Journal Articles
File size: 2196 kb(s)

Abstract: Using sustainable building materials is gaining a significant presence in the United States therefore proving sustainability claims are becoming increasingly more important. Certifying wood products as green building materials is vital for the long-term productivity of the wood building industry and for forest management. This study examined hardwood lumber manufacturing using Life-Cycle Inventory methodology. Material flow and energy type and use were identified for hardwood sawmills in the northeastern United States. Energy consumption of 608 MJ of electricity and 5,800 MJ of thermal energy per m3 were determined for the manufacturing of planed dry hardwood lumber from incoming logs. Burning green wood residues on-site generate the most energy. Hardwood log volume conversion to planed dry lumber of 43.7% was estimated. Modeling data estimated biomass and fossil carbon dioxide production of 428 kg per m³ and 139 kg per m³, respectively. Increasing wood fuel use, a carbon-neutral process, would decrease the environmental impact of hardwood lumber manufacturing and increase its value as a green building material.

Keywords: Inventory, Hardwood Sawmills, Northeastern region, United States

Category: Journal Articles
File size: 976 kb(s)

Abstract: Brown-rot fungi such as Postia placenta are common inhabitants of forest ecosystems and are also largely responsible for the destructive decay of wooden structures. Rapid depolymerization of cellulose is a distinguishing feature of brown-rot, but the biochemical mechanisms and underlying genetics are poorly understood. Systematic examination of the P. placenta genome, transcriptome, and secretome revealed unique extracellular enzyme systems, including an unusual repertoire of extracellular glycoside hydrolases. Genes encoding exocellobiohydrolases and cellulose-binding domains, typical of cellulolytic microbes, are absent in this efficient cellulose-degrading fungus.

Keywords: genome, transcriptome, secretome, Postia placenta, lignocellulose conversion

Category: Journal Articles
File size: 976 kb(s)

Abstract: Brown-rot fungi such as Postia placenta are common inhabitants of forest ecosystems and are also largely responsible for the destructive decay of wooden structures. Rapid depolymerization of cellulose is a distinguishing feature of brown-rot, but the biochemical mechanisms and underlying genetics are poorly understood. Systematic examination of the P. placenta genome, transcriptome, and secretome revealed unique extracellular enzyme systems, including an unusual repertoire of extracellular glycoside hydrolases. Genes encoding exocellobiohydrolases and cellulose-binding domains, typical of cellulolytic microbes, are absent in this efficient cellulose-degrading fungus.

Keywords: cellulose, fenton, lignin, cellulase, brown-rot

Category: Journal Articles
File size: 1237 kb(s)

Abstract: Within the past 15 years, at least three bleach plants in North America experienced catastrophic equipment failures associated with the use of 50 wt% peroxide. People were badly injured in two instances, and these mills were fortunate to have avoided fatalities in these events. Hydrogen peroxide can be and has been used safely for many years, but like any strong oxidant, it must be handled with respect. This paper evaluates safety concerns associated with the use of hydrogen peroxide in the bleach plant. Several safety practices are suggested to address issues identified by these explosions and minimize the risk associated with use of peroxide.

Keywords: Hydrogen Peroxide, Environmentally friendly, Dangerous bleaching chemical

Category: Journal Articles
File size: 218 kb(s)

Abstract: Impedance spectra were collected from Southern pine (Pinus spp.) equilibrated to a moisture content 20% and a saturated condition. Cylindrical graphite electrodes were embedded in the wood so that they met nearly endto-end along a line parallel to the grain, and impedance properties were characterized as functions of electrode spacing and electrode contact pressure at frequencies between 1=10^-1 and 3=10⁵ Hz. The data exhibit a low-frequency tail that can be fit with a Warburg element, indicative of a diffusive motion of charge carriers. Values of the Warburg impedance were compared with previously published data on molar conductivities of endogenous mineral ions in wood. The data suggest that mineral ions are the predominant charge carriers in wood at low frequencies and high moisture contents based on the strong correlation between the Warburg impedance and molar conductivities.

Keywords: constant phase element; electrical relaxation; electrochemical impedance spectroscopy (EIS); ionic conduction; Warburg impedance.

Category: Journal Articles
File size: 573 kb(s)

Abstract: A bridge consisting of three 6.7-m spans with a stress-laminated deck was constructed in 1991 in the Spirit Creek State Forest near Augusta, Georgia. The bridge was constructed by the Georgia Forestry Commission, with guidance from the U.S. Department of Agriculture, Forest Service, orest Products Laboratory (FPL). Water-borne chromated copper arsenate lumber was used for the deck, instead of the oil-borne preservatives recommended by AASHTO. The bridge was initially monitored by FPL and remained in service from 1994 to 2001 with no maintenance, at which time the bridge was inspected and load tested and the posttensioning bars were restressed. In 2005 the bridge was again inspected and load tested, and the bars were retensioned. The results of the inspection and load tests are presented. The overall condition of the bridge is reported, along ith details on the moisture condition, overall deck deflection, and timber trains under load. Details on the loss of posttensioning forces in the ars, and an investigation of the causes of this loss, are presented.

Keywords: Category IIC

Category: Journal Articles
File size: 373 kb(s)

Abstract: As an adherend, wood is structurally, chemically, and mechanically more complex than metals or plastics, and the largest source of this complexity is wood's chemical and mechanical inhomogeneities. Understanding and predicting the performance of adhesively bonded wood requires knowledge of the interactions occurring at length scales ranging from the macro down to the molecular level of chemical interactions. This work investigates such interactions occurring at and below the micrometer range using nanoindentation.

Keywords: Nanoindentation methods, wood adhesive bond lines

Category: Journal Articles
File size: 380 kb(s)

Abstract: Compacted powders of commercially available nano- andmicroparticles of silver were used to successfully induce the surface enhanced Raman scattering (SERS) effect in spruce milled-wood lignin (MWL). For the two silver particle sizes used in this investigation, the spectra were mostly similar. Some general characteristics of the lignin SERS spectrum are described. The ERS techniquewas found to be sensitive for detecting lignin. Significant spectral changes were present between the SERS and normal Raman spectra of MWL. The SERS spectrum was assigned on the basis of literature-reported vibrational assignments of lignin and itsmodels. Based on significant changes in Raman features,we propose that the lignin is strongly adsorbed on silver. To determinewhether SERS of lignin can be obtained directly fromwood without its isolation, Wiley-milled sprucewood(WMW) dsorbed on silver was studied. The results indicated that not only the surface-enhancement effect was successfully induced in theWMW, but that its spectrum was similar to MWL SERS. Moreover, for WMW, no signals from the carbohydrate components were observed, and therefore, lignin was detected selectively. This nano- and microparticle-basedmolecularly specificmethod is expected to make a significant contribution in identifying and investigating lignin in various lignin-containing materials.

Keywords: surface-enhanced Raman scattering (SERS); lignin; cellulose; wood; silver; nano; micro; benzoic acid; muconic acid

Category: Journal Articles
File size: 111 kb(s)

Abstract: Although the prefix 'nano' has been added to almost every contemporary concept and device, it will probably come as a surprise to readers to learn that the second International Conference on Nanotechnology for the Forest Products Industry1 took place in June. Nearly 200 researchers from the paper- and wood-products communities gathered at the conference to discuss ways of addressing the challenges facing these industries, including overcapacity and the need for national industries to remain competitive in an international environment. Having a history of seeking technological solutions to manufacturing problems, researchers are exploring nanotechnology to solve problems that limit efficiency and to seek new value streams from forest resources.

Keywords: cellulose, nanofibrils, composites, wood

Category: Journal Articles
File size: 1372 kb(s)

Abstract: The ligninolytic fungus Phanerochaete chrysosporium oxidized phenanthrene and phenanthrene-9,10-quinone (PQ) at their C-9 and C-10 positions to give a ring-fission product, 2,2'-diphenic acid (DPA), which was identified in chromatographic and isotope dilution experiments. DPA formation from phenanthrene was somewhat greater in low-nitrogen (ligninolytic) cultures than in high-nitrogen (nonligninolytic) cultures and did not occur in uninoculated cultures. The oxidation of PQ to DPA involved both fungal and abiotic mechanisms, was unaffected by the level of nitrogen added, and was significantly faster than the cleavage of phenanthrene to DPA. Phenanthrene-trans-9,10-dihydrodiol, which was previously shown to be the principal phenanthrene metabolite in nonligninolytic P. chrysosporium cultures, was not formed in the ligninolytic cultures employed here. These results suggest that phenanthrene degradation by ligninolytic P. chrysosporium proceeds in order from phenanthrene -- PQ -* DPA, involves both ligninolytic and nonligninolytic enzymes, and is not initiated by a classical microsomal cytochrome P-450. The extracellular lignin peroxidases of P. chrysosporium were not able to oxidize phenanthrene in vitro and therefore are also unlikely to catalyze the first step of phenanthrene degradation in vivo. Both phenanthrene and PQ were mineralized to similar extents by the fungus, which supports the intermediacy of PQ in phenanthrene degradation, but both compounds were mineralized significantly less than the structurally related lignin peroxidase substrate pyrene was.

Keywords: oxidative degradation, phenanthrene, phanerochaete chrysosporium

Category: Journal Articles
File size: 236 kb(s)

Abstract: Wood is a hygroscopic material which contains water in varying amounts, depending upon the relative humidity and temperature of the surrounding atmosphere.

Keywords: wood, lumber, physical properties. mechanical properties, thermal properties, moisture content, strength properties

Category: Journal Articles
File size: 387 kb(s)

Abstract: Stress-graded structural lumber is produced under two systems: visual grading and machine grading. Visual structural grading is the oldest stress grading system. It is based on the premise that the mechanical properties of lumber differ from those of clear wood because many growth characteristics of lumber affect its properties: these characteristics can be seen and judged by eye (ASTM D 245). The principal growth feature affecting lumber properties are the size and location of knots, sloping grain, and density.

Keywords: Solid-sawn lumber, visual grades, mechanical grades, design values, structural composite lumber, glued-laminated timbers, round timbers

Category: Journal Articles
File size: 102 kb(s)

Abstract: Structural panel products are a family of wood products made by bunding veneer, strands, particles, or fibers of wood into flat sheets. The members of this family are (1) plywood, which consists of products made completely or in part from wood veneer; (2) flakeboard, made from strands, wafers, or flakes; (3) particleboard, made from particles; and (4) fiberboard and hardboard, made from wood fibers. Plywood and flakeboard make up a large percentage of the panels used in structural applications such as roof, wall, and floor sheathing; thus, only those two types will be described here.

Keywords: structural panels, plywood, flakeboard, particleboard, fiberboard, hardboard

Category: Journal Articles
File size: 809 kb(s)

Abstract: Water-base pressure sensitive adhesives dominate the market of adhesives applied to paper. These materials are formulated as emulsions of acrylic polymers in water. Surfactants are used to stabilize the hydrophobic polymer particles. When water-based adhesives are dried, particles coalesce and surfactant segregates to interparticle domains that provide pathways for water to enter the adhesive film. Atomic force microscopy, under humidity controlled conditions, has been used to characterize formation of these structures in adhesive films. Surfactant rich domains, which strongly interact with water, lead to dramatic differences between the wet and dry mechanical properties of adhesive films. The efficiency of adhesive removal by slotted screening was observed to correlate with wet tensile strength for a set of model adhesives. In contrast, dry tensile strength is not useful for predicting performance during recycling operations.

Keywords: Water-Based Acrylic, Pressure sensitive adhesive, Aqueous Environments

Category: Journal Articles
File size: 240 kb(s)

Abstract: The extracellular heme-thiolate peroxygenase of Agrocybe aegerita catalyzed the H2O2-dependent hydroxylation of 2-phenoxypropionic acid (POPA) to give the herbicide precursor 2-(4-hydroxyphenoxy) propionic acid (HPOPA). The reaction proceeded regioselectively with an isomeric purity near 98%, and yielded the desired R-isomer of HPOPA with an enantiomeric excess of 60%. ¹⁸O-labeling experiments showed that the phenolic hydroxyl in HPOPA originated from H2O2, which establishes that the reaction is mechanistically a peroxygenation. Our results raise the possibility that fungal peroxygenases may be useful for a variety of organic oxidations.

Keywords: Peroxidase Peroxygenase; Oxygenase; Cytochrome P450; Hydroxylation; 2-(4-Hydroxyphenoxy)propionic acid, Ascorbic acid

Category: Journal Articles
File size: 216 kb(s)

Abstract: The extracellular heme-thiolate peroxygenase of Agrocybe aegerita catalyzed the H₂O²-dependent hydroxylation of 2-phenoxypropionic acid (POPA) to give the herbicide precursor 2-(4-hydroxyphenoxy) propionic acid (HPOPA). The reaction proceeded regioselectively with an isomeric purity nearand yielded the desired R-isomer of HPOPA with an enantiomeric excess of 60%. O-labeling experiments showed that the phenolic hydroxyl in HPOPA originated from H2O2, which establishes that the reaction is mechanistically a peroxygenation. Our results raise the possibility that fungal peroxygenases may be useful for a variety of organic oxidations.

Keywords: Peroxidase, Peroxygenase, Oxygenase, Cytochrome P450, Hydroxylation, 2-(4-Hydroxyphenoxy)propionic acid, Ascorbic acid

Category: Journal Articles
File size: 216 kb(s)

Abstract: The density gradient column method was used to determine the effects of uniform and non-uniform pulping processes on variation in individual fiber lignin concentrations of the resulting pulps. A density gradient column uses solvents of different densities and a mixing process to produce a column of liquid with a smooth transition from higher density at the bottom to lower density at the top. Properly prepared pulp fibers float in the column, stabilizing t the level where the mixed solvent density equals the density of the fiber. Because lignin is the lowest density component of pulp fibers and has the largest influence on fiber density, the column effectively separates fibers by lignin concentration and allows them to be counted and the distribution of lignin concentrations determined. Ten experimental kraft pulps and three commercial pulps were evaluated. The laboratory pulps were produced from a single loblolly pine tree using 2.5-mm and 10-mm chips. All cooks used a 24% effective alkali (EA) charge on wood, 6-to-1 liquor-to-wood ratio, and 30% sulfidity. The cooking schedule was constant at 60 min rise to temperature and 240 min at temperature. The maximum cooking temperature was varied from 150°C to 170°C to provide a kappa number variation from about 60 to approximately 20. Pulps produced from 2.5-mm-thick chips gave uniform density distributions that were accurately modeled with a standard normal distribution. However, pulps produced using 10-mm chips contained an extended low density (high kappa number) tail that can be modeled as a second, high-standard-deviation distribution. The two distributions can be explained as that portion of the wood chips with ready access to pulping chemicals and rate controlled by pulping kinetics, and the interior portion of the chip where chemical penetration is slow and the pulping rate is controlled by diffusion. The commercial pulps show variations in the lignin concentration standard deviation that demonstrate improved uniformity when using modified continuous cooking processes.

Keywords: Density gradient column method; fiber lignin distributions

Category: Journal Articles
File size: 332 kb(s)

Abstract: In February 2008, the Western Governors' Association adopted a policy reaffirming the governors' strong commitment to enhance and diversify the region's transportation fuels portfolio. The Strategic Assessment of Bioenergy Development in the West represents a major step in fulfilling that commitment and expands upon earlier work through WGA's Clean and Diversified Energy Initiative and the Transportation Fuels Initiative. The Bioenergy Assessment Team was formed to examine the potential for future development and to create a comprehensive framework to assess environmental, technical and socioeconomic impacts associated with national, state and regional bioenergy and biomass management policies. This assessment will assist the governors individually and collectively as they develop bioenergy policies.

Keywords: Strategic assessment, bioenergy, biomass resource assessment, supply analysis

Category: Journal Articles
File size: 8404 kb(s)

Abstract: In February 2008, the Western Governors' Association adopted a policy reaffirming the governors' strong commitment to enhance and diversify the region's transportation fuels portfolio. The Strategic Assessment of Bioenergy Developmentin the West represents a major step in fulfilling that commitment and expands upon earlier work through WGA's Clean and Diversified Energy Initiative and the ransportation Fuels Initiative. The Bioenergy Assessment Team was formed to xamine the potential for future development and to create a comprehensive framework to assess environmental, technical and socioeconomic impacts associated ith national, state and regional bioenergy and biomass management policies. This sessment will assist the governors individually and collectively as they develop bioenergy policies.

Keywords: Strategic Assessment, Bioenergy, spatial analysis, supply curve

Category: Journal Articles
File size: 8943 kb(s)

Abstract: A modified fiber-orientation tester uses polarization processing of reflected light from paper to provide both surface and subsurface fiber-orientation angles. This makes possible both thickness-direction and cross-machine-direction profiling. Results obtained from two Fourdrinier machines show that subsurface angles are not well represented by a trended average of felt and wire surface angles. In fact, they can lie outside the range of surface angles and change sign unexpectedly. Sign changes suggest that the cross flows on the wire responsible for fiber misalignment may have strong shearing components that could be important to formation and hard-to-handle dimensional stability issues such as cockle. Results from office papers made on two Fourdrinier machines show significant difference in subsurface fiber-orientation-angle behavior. These include results from two papers from the same machine differing in grammage by only 10 g/m² (gsm).

Keywords: surface and subsurface, fiber-orientation-angle, three office papers

Category: Journal Articles
File size: 120 kb(s)

Abstract: McKay's chi-square approximation for the coefficient of variation is type II noncentral beta distributed and asymptotically normal with mean n - 1 and variance smaller than 2(n - 1).

Keywords: Coef?cient of variation; McKay's approximation; Noncentral beta distribution

Category: Journal Articles
File size: 643 kb(s)

Abstract: This study examines the effect of cyclic RH exposure on MC and thickness swelling (TS) of oriented strandboard (OSB) made from fire-impacted trees. Two specimens were cut from the center of each OSB panel and one was edge-sealed. After being conditioned to 65% RH, specimens were placed in a climate-controlled chamber and subjected to three cyclic changes of 90 - 30% RH at 20°C. Experimental data were characterized by three time-dependent MC or TS models: logarithmic, power law, and exponential. The latter two models gave the best fits showing that edge-sealing reduced the extent of swelling during adsorption and reduced the moisture loss at desorption. The models also described the effect of burnt level and bark throughout the humidity exposure cycles. The exponential model revealed no significant effect of burnt level on the panel TS. Both the power law and exponential models indicated that addition of charred bark to the panels significantly decreased the maximum amount of moisture and thickness change. The exponential model revealed an increase in equilibrium TS at the end of each RH cycle compared with the end of precyclic desorption. True nonrecoverable TS was difficult to discern in Cycle 1 because of moisture hysteresis, but the nonrecoverable effect was evident in Cycles 2 and 3.

Keywords: Fire-impacted wood, oriented strandboard, cyclic humidity exposure, thickness swelling modeling.

Category: Journal Articles
File size: 1496 kb(s)

Abstract: Effective mitigation of external fires on structures can be achieved flexibly, economically, and aesthetically by (1) preventing large-area ignition on structures from close proximity of burning vegetations and (2) stopping flame travel from firebrands landing on combustible building objects. In using bench-scale and mid-scale fire tests to obtain fire growth properties on common building construction and landscaping plants, a model is being developed to use fast predictive methods suitable for changing environments imposed on the parcel lot consisting of structures and ornamental plants. When fully implemented and validated, the property owners and associated professionals will be able to view realistically in real-time (or faster) the various fire scenarios with the ability to select building materials and shapes as well as select ornamental plant species and placement for achieving the desired fire mitigation. Because of the analytical model's ability to respond to the changing 'parcel' environments of wind, temperature, humidity, moisture, sunshine, and wildfire sources of heat and embers, as well as to variations in building construction and ornamental plants, means that analysis can be done eventually for various neighborhoods. The mathematical formulation presented at the 2006 BCC Symposium is partially shown here and some results are compared with (1) our refurbished and modified Lateral Ignition and Flame Travel Test (ASTM E1321 and E1317), (2) specialized testing of Class B burning brand (ASTM E108) in the Cone Calorimeter (ASTM E1354), (3) room-corner tests with OSB (ISO 9705), and (4) Cone Calorimeter tests of fire resistive materials such as FRT plywood and single-layer stucco-coated OSB. A preliminary Fortran dll file has been generated for use in other models, such as ecoSmart Fire.

Keywords: wildland fire management, policy, science, International Association of Wildland Fire, Joint Fire Science Program

Category: Research Notes
File size: 182 kb(s)

Abstract: This note presents theoretical analyses for determination of dimensions of structural sandwich of minimum weight that will have certain stiffness and load-carrying capabilities. Included is a brief discussion of the resultant minimum weight configurations.

Keywords: structural sandwich, MIL-HDBK-23, Bending Stiffness, Bending Moment Capacity, Compressive Edge Load, Axial Compressive Load

Category: Research Notes
File size: 178 kb(s)

Abstract: The concept of sandwich construction combining thin, strong facings on lightweight, thick cores immediately suggests possibilities of deriving constructions so proportioned that minimum weight for a given stiffness or loading capability is achieved. It is important to realize that the minimum weight construction derived may not be practical because of unusually thin facings which are not available, or some other detail such as an unusually lightweight core of great thickness. Since it is theoretically possible to arrive at impractical designs, various minimum weight analyses should be used with caution for comparing sandwich with other constructions unless the sandwich proportions are examined. Analyses of the efficiency of panels of various sandwich constructions of certain materials have been reported. This note presents some general analyses of minimum weight sandwich considering stiffness, edge load capacity, and bending moment capacity.

Keywords: structural sandwich, MIL-HDBK-23, Bending Stiffness, Bending Moment Capacity, Compressive Edge Load, Axial Compressive Load

Category: Research Notes
File size: 2346 kb(s)

Abstract: This is a progress report on service tests of fence posts, untreated or treated with preservative, conducted either by the Forest Products Laboratory and other branches of the U.S. Forest Service, or by others in cooperation with the Forest Service. The earliest test installations were started in 1908, and new tests have been added in succeeding years. The service records cover a wide variety of post species, 12 methods of treatment, and 73 different preservatives or preservative combina-tions. Actual or estimated life figures are shown for test installations where 10, per-cent or more of the posts had failed at the time of the last inspection. Table 1 is an index to the preservatives and method of treatment reported in table 2.

Keywords: service tests, fence posts, Brush-treated posts, Cold-soaking, Double diffusion, End diffusion, Groundline treatments

Category: Research Notes
File size: 1320 kb(s)

Abstract: This progress report on service tests of fenceposts, untreated or treated with preservative, was conducted either by the Forest Products Laboratory and other branches of the Forest Service, or by others in cooperation with the Forest Service. The earliest test installations were started in 1908, and new tests have been added in succeeding years. The service records cover a wide variety of post species, 12 methods of treatment, and 73 different preservatives or preservative combinations. Actual or estimated life figures are shown for test installations where 10 percent or more of the posts had failed at the time of the last inspection. Table 1 is an index to the presenratives and method of treatment reported in table 2.

Keywords: service tests, fence posts, Brush-treated posts, Cold-soaking, Double diffusion, End diffusion, Groundline treatments, revised

Category: Research Papers
File size: 1648 kb(s)

Abstract: This report presents the results of compression and shear evaluations of two resin-treated paper honeycomb cores. The cores and densities of 1.7 and 3.7 pounds per cubic foot. Cores were evaluated in thicknesses of 1/4 to 2 inches and at several moisture contents ranging up to 80 percent. Compressive strength of 1/4--inch-thick cores was 25 to 80 percent greater than that of 2-inch-thick cores. Compressive strength and modulus of elasticity of cores at 10 percent moisture content were 50 to 70 percent of those at 4 percent moisture content. Cores soaked in water (60 to 80 percent moisture content) had only 20 to 30 percent of the strength and modulus of elasticity of those at 4 percent content. Core shear strength was two to four times as high for 1/4-inch as for 2-inch-thick cores. Core shear strength and modulus of rigidity at 10 percent moisture content was 50 to 70 percent of that at 4 percent moisture content; cores soaked in water had 20 to 40 percent of the and modulus of rigidity of those at 4 percent moisture content. Specimens sheared parallel to the core ribbon direction had about twice the strength and three the stiffness as those of the same core sheared perpendicular to the core ribbon direction.

Keywords: Resin-treated paper, honeycomb cores, moisture content, mechanical properties

Category: Research Papers
File size: 1456 kb(s)

Abstract: Describes properties of 156 U.S. tree species that affect their manufacture and use as veneer or products made from veneer. Each species is rated for use in the general categories of construction plywood, decorative face veneer, inner plies of decorative panels, or container veneer and plywood.

Keywords: Veneer species, grown in United States, Volume, log characteristics, mechanical properties, cutting, drying

Category: Research In Progress
File size: 437 kb(s)

Abstract: Covered bridges are complex structures containing eccentric connections, various load paths, connection uncertainty between the subassemblies (trusses and arches), and interaction between trusses and their housing (Figure 1). When these factors are combined with material variability, the conclusion that some bridges just shouldn't be standing is an understandable option. As noted in the Federal Highway Administration (FHWA) publication FHWA-HRT-04-098, Covered Bridge Manual, there are inconsistencies with the assumptions of traditional simple, static analyses of trusses that are frequently used to analyze covered bridges. For example, timber trusses tend to behave more like frames than as trusses; both axial and bending forces are carried in their members and across joints. As such, over-simplified and inaccurate analyses are often performed and overly conservative safety factors applied to account for known inaccuracies. This frequently leads to the conclusion that a historic covered bridge is inadequate to carry the required design load or to the use of inappropriate rehabilitation recommendations.

Keywords: covered bridge; analytical techniques; structural performance; connection models; modeling techniques

Category: Research In Progress
File size: 244 kb(s)

Abstract: Lateral force resisting systems for wood-framed buildings typically consist of wood structural panel shear walls with anchor bolts located at the edge of foundations. The resisting system is relied upon to defend against wind and seismic loading conditions. For wood construction, anchor bolt connections often have an edge distance of 1-3/4 in. from the bolt center line to the face of the concrete slab or footing. Engineers have historically anticipated the controlling failure of this connection to occur between the anchor bolt and the wood sill plate, but current design provisions predict concrete break-out failures. With little information, engineers and code official are forced to specify lower anchor bolt capacities than what has historically been accepted.

Keywords: wood sole plate; concrete anchorage; monotonic loading; cyclic loading; lateral force; anchor bolt capabilities; concrete to wood sill anchorage

Category: Conference Proceedings
File size: 902 kb(s)

Abstract: Mechanical properties of bending stiffness and yield stress were used to evaluate the effects of ultraviolet exposure on natural fiber-thermoplastic composites. Four different specimen formulations were evaluated. Injection molded high density polyethylene (HDPE) served as the polymer base for all formulations. Two lignocellulosic fillers, wood flour and kenaf fiber, were added at 50 percent by weight. Additives consisted of an antioxidant, coupling agent, and ultraviolet (UV) stabilizer. Specimens were exposed in a laboratory weatherometer to high levels of UV radiation and moisture cycling to simulate the effects of sunlight and rain for a 2000-h exposure period. Bending stiffness (modulus of elasticity) and bending yield stress (modulus of rupture) were measured prior to and after specific exposure periods. For the 100 percent HDPE formulation, stiffness increased and yield stress decreased after exposure. For HDPE with additives, no significant changes in mechanical properties occurred after 2,000 hours of exposure. Significant loss in mechanical properties was observed for both fiber-filled formulations. A 42 percent drop in measured stiffness and 24 percent drop in measured bending strength were recorded for the kenaf fiber formulation due to the 2,000-hr. exposure. A less dramatic drop in stiffness (33%) and strength (20%) was recorded for the wood flour formulation. For all formulations except HDPE with no additives exposed for 1,000 hours, the orientation of the degraded surface in bending, whether on the tension or compression side, had no significant effect on stiffness or strength.

Category: Conference Proceedings
File size: 38 kb(s)

Abstract: Aspen fiber-polypropylene composites were prepared with various levels of fiber (0,30%, 40%, 50%, and 60%), polypropylene (PP) (100%, 98%, 70%, 68%, 60%, 58%, 50%, 48%, 40%, and 38%), and the compatibilizer maleated polypropylene (MAPP) (0 and 2%). Specimens were either subjected to 10 cycles of 1 week room temperature water soaking-oven drying or 2-hr. boiling wateroven drying. Thickness swelling and weight loss were calculated. Specimens were then exposed to the brown-rot fungus G. trabeum or the white-rot fungus C. versicolor for 12 weeks to determine the effect of repeated water cycling on decay. Results indicate that as the amount of aspen fiber increases there is an increase in weight and thickness swelling, as well as an increase in fungal attack after the water cycling tests. Presence of the compatibilizer seems to have an effect on the moisture weight gain, thickness swelling, and attack by fungi.

Category: Conference Proceedings
File size: 493 kb(s)

Abstract: Considerable interest has been generated in the use of lignocellulosic fibers and wastes (both agricultural and wood based) as fillers and reinforcements in thermoplastics. In general, present technologies limit fiber loading in thermoplastics to about 60 percent by weight of fiber. To produce high fiber content composites for commercial use while maintaining adequate mechanical properties requires innovative processing techniques. A new technique has been developed that allows very high fiber loading. We have processed composites up to about 95 percent by weight of fiber in polypropylene (PP). The process involves some additional processing steps, in addition to conventional compounding techniques, to achieve such high fiber content in PP.

Category: Conference Proceedings
File size: 118 kb(s)

Abstract: Techniques for compounding and injection molding ultra-pure cellulose fibers into nylon 6 and other thermoplastics will be described. Low temperature compounding (LTC) is a technique that provides a processing route to utilize ultrapure cellulose fiber as a reinforcement in resins with melting points greater than 220°C. In particular, nylon 6 has a melting point of 221°C which is well above the commonly stated belief that cellulose fiber should not be compounded above the 200°C benchmark. By understanding and utilizing the viscosity shear heating effects of cellulose fiber/nylon 6 composite systems, the LTC method provides high quality composite pellets for injection molding. Low temperature injection molding (LTIM) is a technique that will be described which provides a means of producing ASTM standard test samples for mechanical property evaluation. Other recent publications (1-3) have described the mechanical properties of cellulose fiber/nylon 6 composites. This discussion will focus on LTC and LTIM methods of producing the cellulose fiber/ nylon 6 composite pellets and test samples.

Category: Conference Proceedings
File size: 469 kb(s)

Abstract: High purity wood cellulose fibers (95% a -cellulose content) can provide good reinforcement properties for engineering thermoplastics melting above 200° C such as nylon 6 to yield mechanical properties that are intermediate between glass fiber and mineral materials such as wollastonite. Composite discoloration and decomposition are minimized using such high purity wood pulp fibers. At the levels employed (30% to 33% by weight), processing temperatures in both compounding and injection molding can be substantially lowered. Of six wood pulps studied, two with a -cellulose contents greater than 97 percent gave the best overall results with one of them appearing superior (a hardwood kraft pulp). In this study, pulp fibers were granulated with a rotary knife cutter prior to compounding them with nylon 6; this step reduced fiber length. It was later found that pelletizing the fibers helps preserve original fiber length, improves processing, and leads to better mechanical properties (at times exceeding those for glass fibers). Mercerization of the hardwood kraft fibers results in additional processing and mechanical property improvements. These studies with nylon 6 are presented and discussed in this paper along with some limited results obtained using certain process additives as well as other engineering plastics.

Category: Research Notes
File size: 383 kb(s)

Abstract: This report provides general and statistical information on forests products markets in terms of production, trade, consumption, and prices, as well as specifics describing the current state of the U.S. economy. Market developments are described for sawn softwood, sawn hardwood, softwood and hardwood log trade, pulpwood, wood-based panels, paper and paperboard, fuelwood, and forest product prices. The table presents detailed information and projections for 2001.

Keywords: production, trade, prices

Category: Research Papers
File size: 1627 kb(s)

Abstract: This report presents annual data but is published every 2 years. The data present current and historical information on the production, trade, consumption, and prices of timber products in the United States. The report focuses on national statistics but includes some data for individual States and regions and for Canada. The data were collected from industry trade associations and government agencies. They are intended for use by forest land managers, forest industries, trade associations, forestry schools, renewable resource organizations, individuals in the major timber producing and consuming countries of the world, and the general public. A major use of the data is tracking industry production and consumption trends with time. One of the major shifts occurring recently in the wood using industry is that both production and consumption of roundwood per capita have declined even though consumption of products per capita is increasing - due to increased paper recycling, increased imports, and increased processing efficiency. Consumption per capita in roundwood equivalent has decreased during the past 15 years from 80 ft³ per capita to 67 ft³ per capita in 2002. In the 1960s and 1970s, consumption averaged about 70 ft³ per capita.

Keywords: production, consumption, import, export

Category: Research In Progress
File size: 290 kb(s)

Abstract: Shear walls and diaphragms are the primary lateral-load-resisting elements in wood-frame construction. Such buildings have performed relatively well in earthquakes and hurricanes from the life safety perspective. However, property losses from natural disaster can be high. For example, in the January 17, 1994, Northridge earthquake in the Los Angeles metropolitan region, property losses were attributed predominately to damages in wood-frame housing, accounting for over half of the $40 billion property damage and approximately 48,000 uninhabitable buildings. Better understanding and improvement of these lateral-load-resistive systems are needed to further enhance wood-frame construction as a competitive solution in wide applications, including residential buildings and engineered mid-rise construction.

Keywords: force transfer; shear walls; design methods; disaster performance; wood-frame construction; force behavior; force transfer around openings

Category: FPL News
File size: 178 kb(s)

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Category: FPL News
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Category: Research Papers
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Abstract: Between 2006 and the end of 2009, the production capacity of the softwood lumber sector covered by this report in the United States and Canada has shrunk from 190.8 million m³ (nominal) to 166.4 million m³. The corresponding number of mills slumped from 1,025 to 875 over the same time and from 1,322 recorded in 1995. The Canadian capacity went from 88.2 million m³ to 71.6 million m³, a loss of 19%, while the U.S. capacity dropped from 102.6 million m³ to 94.8 million m³, a loss of 8%. These losses are attributable to three unprofitable years of sawmilling caused by the contraction in construction. Construction and repair and remodeling of homes each accounted for about 35% of total lumber consumption in 2006. Their downturn has caused demand to lag substantially behind the capacity that was built up to supply the prior boom. The greater drop in Canadian capacity can be deduced from a number of factors including the imposition of tariffs of up to 15% on exports to the U.S. and the strengthening of the Canadian dollar. Based on underlying population growth, the demand for home building is expected to rebound but somewhat slowly until the overhang of unoccupied homes built in the former building surge is absorbed. Further attrition of capacity is likely, as profitability is unlikely to return until a combination of recovering demand and contracting supply due to further capacity attrition equalize in the market.

Keywords: softwood sawmill capacity; sawmill employment; wood end-use markets; market review; lumber demand and supply

Category: FPL News
File size: 121 kb(s)

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Category: Journal Articles
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Abstract: The brown-rot basidiomycete Gloeophyllum trabeum uses a quinone redox cycle to generate extracellular Fenton reagent, a key component of the biodegradative system expressed by this highly destructive wood decay fungus. The hitherto uncharacterized quinone reductase that drives this cycle is a potential target for inhibitors of wood decay. We have identified the major quinone reductase expressed by G. trabeum under conditions that elicit high levels of quinone redox cycling. The enzyme comprises two identical 22-kDa subunits, each with one molecule of flavin mononucleotide. It is specific for NADH as the reductant and uses the quinones produced by G. trabeum (2,5-dimethoxy-1,4-benzoquinone and 4,5-dimethoxy-1,2-benzoquinone) as electron acceptors. The affinity of the reductase for these quinones is so high that precise kinetic parameters were not obtainable, but it is clear that k_cat/K_m for the quinones is greater than 10⁸ M^-1 s^-1. The reductase is encoded by a gene with substantial similarity to NAD(P)H:quinone reductase genes from other fungi. The G. trabeum quinone reductase may function in quinone detoxification, a role often proposed for these enzymes, but we hypothesize that the fungus has recruited it to drive extracellular oxyradical production.

Category: Journal Articles
File size: 116 kb(s)

Abstract: Abstract We have identified key components of the extracellular oxidative system that the brown rot fungus Gloeophyllum trabeum uses to degrade a recalcitrant polymer, polyethylene glycol, via hydrogen abstraction reactions. G. trabeum produced an extracellular metabolize, 2,5-dimethoxy-1,4-benzoquinone, and reduced it to 2,5-dimethoxyhydroquinone. In the presence of 2,5-dimethox-1,4-benzoquinone, the fungus also reduced extracellular Fe³+ to Fe² + and produced extracelluar H₂O₂. Fe₃+ reduction and H₂O₂ formation both resulted from a direct, non-enzymatic reaction between 2,5-dimethoxyhydroquinone and Fe³+. polyethylene glycol depolymerization by G. trabeum required both 2,5-dimethoxy-1,4-benzoquinone and Fe³+ and was completely inhibited by catalase. These results provide evidence that G. trabeum uses a hydroquinone-driven Fenton reaction to cleave polyethylene glycol. We propose that similar reactions account for the ability of G. trabeum to attack lignocelluose.

Keywords: Brown rot; Wood decay; Quinone redox cycling;Fenton reaction; Hydroxyl radical; Polyethylene glycol

Category: Journal Articles
File size: 279 kb(s)

Abstract: The brown rot fungus Gloeophyllum trabeum uses an extracellular hydroquinone-quinone redox cycle to reduce Fe³⁺ and produce H₂O₂. These reactions generate extracellular Fenton reagent, which enables G. trabeum to degrade a wide variety of organic compounds. We found that G. trabeum secreted two quinones, 2,5-dimethoxy-1,4-benzoquinone (2,5-DMBQ) and 4,5-dimethoxy-1,2-benzoquinone (4,5-DMBQ), that underwent iron-dependent redox cycling. Experiments that monitored the iron- and quinone-dependent cleavage of polyethylene glycol by G. trabeum showed that 2,5-DMBQ was more effective than 4,5-DMBQ in supporting extracellular Fenton chemistry. Two factors contributed to this result. First, G. trabeum reduced 2,5-DMBQ to 2,5-dimethoxyhydroquinone (2,5-DMHQ) much more rapidly than it reduced 4,5-DMBQ to 4,5-dimethoxycatechol (4,5-DMC). Second, although both hydroquinones reduced ferric oxalate complexes, the predominant form of Fe³⁺ in G. trabeum cultures, the 2,5-DMHQ-dependent reaction reduced O2 more rapidly than the 4,5-DMC-dependent reaction. Nevertheless, both hydroquinones probably contribute to the extracellular Fenton chemistry of G. trabeum, because 2,5-DMHQ by itself is an efficient reductant of 4,5-DMBQ. Nevertheless, both hydroquinones probably contribute to the extracellular Fenton chemistry of G. trabeum, because 2,5-DMHQ by itself is an efficient reductant of 4,5-DMBQ.

Category: Journal Articles
File size: 406 kb(s)

Abstract: Although many wood decay basidiomycetes secrete oxidative and hydrolytic enzymes that participate in lignocellulose biodedgradation, it is generally recognized now that these enzymes cannot penetrate sound wood, and that fungi must employ smaller agents to initiate decay. Reactive oxygen species (ROS) are likely candidates, and evidence is accumulating that some wood decay fungi produce these oxidants. For example, we have observed that, when they grow on wood, white rot and brown rot basidiomycetes degrade polyethylene glycol, a recalcitrant polymer that resists attack by species other than nonspecific, extracellular oxidants. By contrast, xylariaceous ascomycetes do not degrade polyethylene glylcol, and therefore do not produce these oxidants when they degrade wood. The ROS that basidiomycetes employ remain unidentified in most cases, but the hydroxyl radical (OH) is a likely participant, because there is a well-established pathway for its production via the Fenton reaction (H₂O₂ + Fe²+ + H+ -> H₂O + Fe³+ + OH). The two best documented fungal pathways for OH production involve the extracellular reduction of Fe3+ and O2 by cellobiose dehydrogenase or by secreted hydroquinones. Peroxyl (ROO) and hydroperoxyl (OOH) radicals, although they are weaker oxidants, may also be involved in wood decay because they are produced via reactions of OH and by some fungal enzymes.

Keywords: Wood decay fungi; White rot; Brown rot; Soft rot; Hydroxyl radical; Peroxyl radicals; Fenton chemistry

Category: Journal Articles
File size: 326 kb(s)

Abstract: Glyoxal oxidase is a copper metalloenzyme produced by the wood-rot fungus Phanerochaete chrysosporium as an essential component of its extracellular lignin degradation pathways. Previous spectroscopic studies on glyoxal oxidase have demonstrated that it contains a free radical-coupled copper active site remarkably similar to that found in another fungal metalloenzyme, galactose oxidase. Alignment of primary structures has allowed four catalytic residues of glyoxal oxidase to be targeted for site-directed mutagenesis in the recombinant protein. Three glyoxal oxidase mutants have been heterologously expressed in both a filamentous fungus (Aspergillus nidulans) and in a methylotrophic yeast (Pichia pastoris), the latter expression system producing as much as 2 g of protein per liter of culture medium under conditions of high density methanol-induced fermentation. Biochemical and spectroscopic characterization of the mutant enzymes supports structural correlations between galactose oxidase and glyoxal oxidase, clearly identifying the catalytically important residues in glyoxal oxidase and demonstrating the functions of each of these residues.

Category: Research In Progress
File size: 329 kb(s)

Abstract: A series of web-based videos is being developed to meet the challenge of keeping the housing industry current on changes in building code requirements and construction techniques. The instructional videos will focus on illustrating construction techniques that minimize moisture-related performance issues in the design and construction of wood-framed wall systems. Three topics will be explored in the video mini-series:

Category: Research In Progress
File size: 287 kb(s)

Abstract: Covered bridges are unique structural systems. Typically designed and constructed in the mid- to early 1800s, covered bridges were originally devised as a way of extending the service life of bridges. This need resulted from the fact that original timber bridges were constructed without the benefit of modern preservatives. Thus, when exposed to the environment they tended to deteriorate relatively quickly. By covering the primary structural components (heavy timber trusses and floor system) with a less expensive and sacrificial covering, a bridge owner could extend the life of a timber bridge.

Keywords: covered bridge; security manual; security strategies; protection solutions; timber bridges; historical bridges

Category: Research Papers
File size: 619 kb(s)

Abstract: Interior gray enzymatic oxidative stain for white woods such as maple has plagued the wood industry for many years because methods that have been found to reduce stain are hard to scale up to industrial levels. We examined possible alternative treatments to eliminate stain in soft maple (Acer rubrum L.), and found that exposure to sulfur dioxide gas eliminates interior gray stain and that staining might occur at different temperatures depending on the age of the logs. Comparing sawn and split boards showed that both eliminated surface stain, but sawing eliminated it to a greater depth. A mild kiln schedule also seems to reduce staining, and this solution may be easier and more economical to implement on an industrial scale, both domestically and internationally, because no other processing is required.

Keywords: soft maple; enzymatic stain; gray stain; interior stain; oxidative stain; sulfur dioxide

Category: TMU Brochure
File size: 129 kb(s)

Abstract: Small- and moderate-sized communities in forested areas face danger from forest fires burning out of control. Even if fires are constrained to the forest and flames do not jump the boundaries to inhabited areas, damages are great.

Keywords: forest fires, boundaries

Category: General Technical Reports
File size: 2505 kb(s)

Abstract: Mold growth was observed in limited areas in a two-story contemporary wood-frame house during the seventh heating season of operation at or near design indoor humidity levels. The house was in a cold climate (Madison, Wisconsin). Humidity levels were estimated as being exceeded in one of 10 homes at this location. Moderate amounts of window condensation were observed during each of the seven heating seasons. Areas of observed mold growth were limited to the lower extremities of windows (near the lower edge of glass panes) and the edges of lower panels of a wood panel entry door that was not equipped with a storm door. Mold growth was also present in sprayed-on cellulose insulation in close proximity to the rim joist (board) in the basement, although this mold was not visible unless the insulation was disturbed and was probably present during previous heating seasons. Mold from these locations was cultured, isolated, and identified morphologically or by DNA sequence. Seven genera of common ascomycetes and deuteromycetes were detected, all of which are commonly associated with indoor air. Penicillium was the most common genus, with at least six different species. The greatest variety of genera (five) occurred in samples taken from interior wood millwork (the edges of panels in the entry door and from a wood window sash). Only two genera were found in a sample taken from the interface between the rim joist board and cellulose insulation. Total spore counts taken in April revealed that on the first and second stories, mold spores were less prevalent than in outdoor air but that mold spores were more prevalent in the basement than in outdoor air.

Keywords: ; mold; spore; indoor air quality; relative humidity; condensation

Category: Journal Articles
File size: 197 kb(s)

Abstract: In the structural analysis of lignins by 13C-NMR, signal overlap limits definitive assignment and accurate intensity measurement. Selective labeling by 13C-enrichment of a specific carbon in lignin enhances its signal intensity in the spectrum. Further enhancement of the specifically labeled carbons can be realized via difference spectra created from the enriched and unenriched samples. Difference 2D 13C-1H correlation (HSQC) NMR spectra, derived from the spectra of specifically 13C-enriched lignin model polymers (so-called dehydrogenation polymers) and their unenriched counterparts, take advantage of the enhanced dispersion afforded by both 13C and 1H chemical shifts, diminishing the difficulties arising from the signal-overlap problem and aiding in definitive signal assignments. In this research, protolignin in xylem cell walls was specifically 13C-enriched at all of the individual phenylpropanoid side-chain carbons by feeding 13Cenriched coniferins to growing stems of Ginkgo biloba. The whole xylem fractions containing 13C-enriched and unenriched protolignins were dissolved in a mixture of N-methylimidazole and DMSO, and then acetylated. Solution state 2D-NMR (HSQC) spectra of the acetylated whole cell wall were acquired. Difference spectra between the walls containing 13C-enriched and unenriched lignins afforded simplified 2D spectra in which well-separated signals were assigned exclusively to the specifically enriched carbons. This novel NMR technique provides a useful tool for elucidation of entire protolignin in the cell wall of ginkgo xylem.

Keywords: carbon-13 enrichment; carbon-13-NMR spectroscopy; dehydrogenation polymer (DHP); 2D­difference NMR spectroscopy; ginkgo; protolignin.

Category: Journal Articles
File size: 576 kb(s)

Abstract: A series of commercial phenol-formaldehyde bonded MDF panels were exposed to a post-manufacture heat-treatment at various temperatures and durations using a hot press and just enough pressure to ensure firm contact between the panel and the press platens. Physical properties and static flexural strengths of the post heat-treated MDF panels were evaluated according to ASTM D 1037 (2002). The results indicated that the post-manufacture heat-treatment of the exterior MDF panels resulted in improvement of thickness swelling. Water absorption and linear expansion properties were adversely affected by the heat-treatment. Modulus of rupture and modulus of elasticity values of the heat-treated panels decreased with increasing treatment temperature. A series of three 12-week creep tests were performed in climatic chambers conditioned at 65% RH, 90% RH, and cyclic 65-90% RH, all at a steady temperature of 20 ?C. The creep tests generally followed procedures as specified in ASTM D 6815-02a (2002). Creep deflections of the panels increased with increasing temperature of the post heat-treatment.

Keywords: Dimensional stability, creep behavior, heat treated, exterior medium density fiberboard

Category: Journal Articles
File size: 3111 kb(s)

Abstract: Moisture control is a critical means of improving the performance of solid-color stain and paint on wood siding. In this article, recommendations are given for constructing a rain screen, sealing the end grain, and back-priming siding to achieve this goal. Rain screen construction and back priming inhibit water absorption and bleed from run-down extractives if water gets behind the siding. Inhibiting water absorption improves dimensional stability of siding, thus improving finish performance. Sealing the end grain with primer decreases paint peeling and bleeding of diffuse extractives near the end of boards. These techniques should be used in combination with structure designs having adequate roof overhangs, ground clearance to bottom course of siding, roof-edge flashing, gutters, and downspouts.

Keywords: painted wood siding, wood siding, siding installation, rain screen, end-grain sealing, back priming, end splitting

Category: Journal Articles
File size: 157 kb(s)

Abstract: Fire-retardant-treated products for exterior applications must be subjected to actual or accelerated weathering prior to fire testing. For fire-retardant-treated wood, the two accelerated weathering methods have been Method A and B of ASTM D 2898. The rain test is Method A of ASTM D 2898. Method B includes exposures to ultraviolet (UV) sunlamps in addition to water sprays. D 2898 was recently revised to include Methods C and D. Method C is the “amended rain test” described in the acceptance criteria for classified wood roof systems (AC107) of the ICC Evaluation Service, Inc. Method D is the alternative rain test described in ASTM E 108 for roof coverings. Issues with the current methods are the limited availability of the UV sunlamps specified in the standard and the large amount of water used that may require special disposal.

Keywords: weathering, fire retardants, wood, UV

Category: Journal Articles
File size: 737 kb(s)

Abstract: Earlier studies [1] have shown that when a hardwood kraft pulp is bleached in the D₀(EO)D₁ED₂ sequence, the brightness of the pulp emerging from the D2 stage can be accurately predicted from the brightness of the pulp entering that stage. The entering brightness, in turn, is a well-defined function of the ratio of the D₁ stage ClO₂ charge to the (EO) stage kappa number. In this study, we use the same model, together with the results of pulping and bleaching experiments on southern U.S. red oak chips, to compare the bleachability characteristics of a conventional kappa number 15 pulp with that of an acid-prehydrolyzed pulp having, after 25% kappa number reduction by prehydrolysis, a similar kappa number. After the (EO) stage, the prehydrolyzed pulp had a lower extracted kappa number, but its brightness was lower than that of the control pulp. Both observations may be interpreted in terms of the relative amounts of residual lignin and hexenuronic acid present in the pulps. The full-sequence model described in our previous paper accurately described bleaching of the prehydrolyzed pulp. The model was used to evaluate the effects of the prehydrolysis on the optimized performance of the D₁ and D₂ stages. The brightness disadvantage of the prehydrolyzed pulp after the D₀(EO) stages persisted over the lower range of D₁ charge multiples but diminished as the multiple was increased, eventually disappearing. The prehydrolyzed pulp required slightly less ClO₂ than the control pulp when bleaching to high brightness in five stages.

Keywords: optimization, ECF bleaching, kraft pulp, acid prehydrolysis, hardwood pulp

Category: Journal Articles
File size: 542 kb(s)

Abstract: A vintage year for sawmilling 2008 was not. In an industry strongly driven to produce, we were apprehensive that firms would be more shy than usual about divulging their 2008 activities. So this year we cast a wider net but, in the end, 149 out of the 200 mills appearing on the Top 200 list, and 48 out of the top 50, volunteered their numbers. For the remainder, capacities usually serve as a good proxy because most mills strive to operate near their limits in good years. This year, however, that approach was unreliable because operating rates varied widely. Among our respondents they ranged from 17 to 107% with an average of 72% (Figure 1). By contrast, 2008 data from the Western Wood Products Assn. (WWPA) implied a 68% U.S. utilization rate. Therefore, to more realistically represent non-respondents, I applied the 68% factor to their capacities, modified by whatever information was available about downtime at specific mills during 2008.

Keywords: sawmill industry, capacity utilization,ownership class, household formations

Category: Journal Articles
File size: 1326 kb(s)

Abstract: Sieving methods have been almost exclusively used for feedstock size-reduction characterization in the biomass refining literature. This study demonstrates a methodology to properly characterize specific surface of biomass substrates through two dimensional measurement of each fiber of the substrate using a wet imaging technique.

Keywords: Specific surface, Bioprocessing, Enzymatic saccharification/hydrolysis, Feedstock processing, Size reduction, Disk and hammer milling, Cellulosic ethanol

Category: Journal Articles
File size: 648 kb(s)

Abstract: This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30-min pretreatment at temperature 180C, SPORL can achieve near-complete cellulose conversion to glucose in a wide range of pretreatment liquor of pH 2.0 - 4.5 in only about 10 h enzymatic hydrolysis. The enzyme loading was about 20 FPU cellulase plus 30 CBU b-glucosidase per gram of cellulose. The production of fermentation inhibitor furfural was less than 20 mg/g of aspen wood at pH 4.5. With pH 4.5, SPORL avoided reactor corrosion problem and eliminated the need for substrate neutralization prior to enzymatic hydrolysis. Similar results were obtained from maple and eucalyptus.

Keywords: sulfite pretreatment, recalcitrance of lignocellulose (SPORL), Saccharification of hardwoods

Category: Journal Articles
File size: 2930 kb(s)

Abstract: To take advantage of nanoscale features in plant cell walls and create our own nanostructures based on plant biomass, we must make reliable measurements at the nanoscale. Although nanoscale measurement methods have expanded in recent years, not all these techniques are useful for soft, hydrophilic, nonconducting biomass specimens. Here we discuss those methods with the potential to be particularly useful in studying nanoscale properties of plant biomass. In contrast to most engineering materials, plant biomass structure changes with water availability. Water swells biomass, creating pores that transport enzymes and reagents into and out of the cell wall during processing. Therefore we begin with a description of basic interactions of water and biomass. Nanoscale accessibility and reactivity of the cell wall are often critical to bioprocessing, so we discuss several methods of evaluating these properties. This chapter also describes methods to measure cellulose crystallinity, because crystallinity affects properties and crystallites are an interesting material in themselves. Finally the chapter reviews microscopic and spectroscopic methods useful for the study of biomass at the nanoscale.

Keywords: Characterization, tools, Biomass, Nanometer scale

Category: Journal Articles
File size: 2691 kb(s)

Abstract: Complete cellulase, an endoglucanase (EGV) with cellulose-binding domain (CBD) and a mutant endoglucanase without CBD (EGI) were utilized for the hydrolysis of a fully bleached reed Kraft pulp sample. The changes of microfibrils on the fiber surface were examined with tapping mode atomic force microscopy (TM-AFM) phase imaging. The results indicated that complete cellulase could either peel the fibrillar bundles along the microfibrils (peeling) or cut microfibrils into short length across the length direction (cutting) during the process. After 24 h treatment, most orientated microfibrils on the cellulose fiber surface were degraded into fragments by the complete cellulase. Incubation with endoglucanase (EGV or EGI) also caused peeling action. But no significant size reduction of microfibrils length was observed, which was probably due to the absence of cellobiohydrolase. The AFM phase imaging clearly revealed that individual EGV particles were adsorbed onto the surface of a cellulose fiber and may be bound to several microfibrils.

Keywords: Ultrastructure, Cellulose, Enzymatic hydrolysis, Cellulases, Micro?brils, Atomic force microscopy (AFM), Phase imaging, Endoglucanase (EG), Cellulose-binding domain (CBD)

Category: Research Notes
File size: 568 kb(s)

Abstract: This report discusses the screening of various adhesive and mastic systems for possible use in assembling lightweight wood containers. Results showed that dynamic tests of simulated box corners correlated reasonably well with rough handling evaluations of eight selected systems when used to assemble lightweight wood boxes made from a Group I container wood. Conventionally nailed specimens were used as the control. The impact tests, as well as the rough handling tests, showed that a system should exhibit a certain degree of resilience. Diagonal compression tests indicated that a system should possess minimum creep characteristics.

Keywords: assembly, wood containers, adhesives,

Category: Research Notes
File size: 201 kb(s)

Abstract: During recent years considerable research and development work have been done on high-strength, durable adhesives for use in bonding metals. Much of this is also applicable for gluing wood to metal. The woodworking adhesives, such as animal, vegetable, casein, urea resin, phenol resin, and resorcinol resin, have not been found entirely suitable for this purpose. They usually are not elastic enough to distribute the stresses encountered in service when two dissimilar materials, such as wood and metal, are bonded together. Also, they generally do not adhere well to the surfaces of metals. Therefore, more elastic materials, such as vinyl resins and natural and synthetic rubbers, have been used in combination with such thermosetting resins as phenol-formaldehyde to produce adhesive formulations that have the proper elasticity and adhere well to both wood and metals.

Keywords: adhesive bonding, wood, metal, thermosetting resins, synthetic rubbers, phenol-formaldehyde

Category: Research Notes
File size: 673 kb(s)

Abstract: Sound insulation properties of an otherwise satisfactory wall or floor can often be nullified when a noise flanks (bypasses) this surface. This applies to all types of construction, including wood frame, and is especially important in multifamily dwellings.

Keywords: Airborne noise control, Bathroom, Mechanical exhaust systems

Category: Research Notes
File size: 240 kb(s)

Abstract: An analog computer is described that was developed at the Forest Products Laboratory to predict surface temperatures of wood and wood products under any given environmental conditions. The solution from the computer can be used to provide input to an analog simulator, also developed at the Laboratory, for measuring heat flow through walls. Predictions by the computer are based on solving an equation of energy balance in terms of surface temperature in which each factor in the equation is represented by a voltage.

Keywords: weathering of wood, analog computer, surface temperatures,

Category: Research Notes
File size: 286 kb(s)

Abstract: Angelique has for many years been incorrectly identified with the botanical name Dicorynia paraensis Benth. It differs from this species and from other described species of Dicorynia in the structure of the flowers and its restricted range of growth. Presently known as Dicorynia guianensis, angelique occurs only in French Guiana and Surinam. Dicorynia paraensis occurs along the Rio Negro and its tributaries in Brazil's Amazonas Territory. Aside from angelique, or basra locus as it is also known, the characteristics and properties of the various Dicorynia species are practically unknown at this time.

Keywords: ANGELIQUE, Dicorynia guianensis Amsh., Mechanical Properties, Machining Properties, Seasoning

Category: Research Notes
File size: 160 kb(s)

Abstract: Engineers, chemists, architects, furniture designers, and other major users of forest products think of wood primarily as an engineering material that has a rather wide range of physical properties and comes in a variety of sizes, grades, colors, grain patterns, and textures. They will continue to use wood as a raw material only to the extent that it is readily available, reasonable in price, and better adapted to their particular product or use than metals, plastics, or some competing organic fiber. Their choice of materials is little influenced by sentiment, forestry tradition, watershed protection problems, recreational needs, or even by the striking beauty of a fine stand of tall, straight, clean-boled trees. The important pulp and paper industry, for example, probably would not hesitate in turning to bagasse, cattails, or even corn silk, if such materials proved cheaper or better adapted to their product than wood fiber.

Keywords: Breeding, High-quality wood, Genetics Research

Category: Research Notes
File size: 1662 kb(s)

Abstract: This report presents curves of coefficients and formulas for use in calculating the buckling of flat panels of sandwich construction under edgewise compressive loads. The curves were derived for sandwich panels having one facing of either of two orthotropic materials, the other facing of an isotropic material; both facings of orthotropic material; both facings of isotropic material; and cores of orthotropic or isotropic material. Parameters are chosen so that facings may be of different thicknesses and so that isotropic facings can also be of different isotropic materials.

Keywords: BUCKLING COEFFICIENTS, EDGEWISE COMPRESSION, edgewise compressive loads, Facing Elastic Properties

Category: Research Notes
File size: 735 kb(s)

Abstract: This Research Note presents species correction data for use with electric moisture meters in measuring the moisture content of five wood species grown in Hawaii, namely: saligna and robusta eucalyptus ( Eucalyptus saligna and Eucalyptus robusta ), silk-oak ( Grevillea robusta ), ohia ( Metrosideros collina ), and koa ( Acacia koa ). Indexes of direct current electrical resistance and radio frequency power absorption were obtained at a temperature of 80° F. and at moisture content values ranging from about 6 percent to above the fiber saturation point for each species.

Keywords: Calibration, Moisture meters, Hawaii

Category: Research Notes
File size: 152 kb(s)

Abstract: Various chemical treatments have been investigated at the Forest Products Laboratory for improving the compressive strength of linerboard exposed at high humidities and after water-soaking. Phenolic resins have been among the more promising chemicals studied, but they vary in performance. The low-condensed water-soluble phenolic resins have given some of the highest compressive strengths, but generally caused more embrittlement of the board, as noted by low tearing resistance and folding endurance. The medium-condensed phenolic resins gave only moderate increases in compressive strength but did not produce as great a loss in other desirable properties.

Keywords: Chemical treatments, compressive strength, linerboard, moisture

Category: Research Notes
File size: 210 kb(s)

Abstract: Flammability tests were conducted with four 8-foot tunnel furnaces on matched samples of 14 different materials, and the results compared. The average flame-spread index value for each material with any one of the furnaces was usually within plus or minus 10 percent of the average for the material by the other three furnaces. The heat-contributed and smokeindex values showed greater variability than the flame-spread index values. In general, the correlations obtained in this series of tests were similar to those reported for the two other flame-spread methods-ASTM E84 (25-foot tunnel furnace) and ASTM E162 (radiant panel furnace).

Keywords: Tunnel furnaces, flammability of wood, flame-spread index values

Category: Research Notes
File size: 923 kb(s)

Abstract: Methods and equipment have been developed to determine the dynamic tensile characteristics of paperboard and corrugated fiberboard. A flywheel-type test machine has been constructed and suitable instrumentation has been developed. Preliminary investigations of paperboard indicate that tensile strength increases approximately as a logarithmic function of the loading rate.

Keywords: Dynamic tension testing, paperboard, corrugated fiberboard,

Category: Research Notes
File size: 687 kb(s)

Abstract: Since wood foundation piles are normally used under conditions of confining lateral pressure from the soil in which they are imbedded, it has been suggested this pressure may have an effect upon the compression parallel-to-the-grain strength of the piles. Accordingly, a study was conducted to evaluate the effect of this pressure on the compression-parallel strength of small clear specimens of Douglas-fir and red oak. To simulate earth pressures, oil pressures of 50 and 100 pounds per square inch were used. No effect was found on the strength of the two species at either pressure.

Keywords: Douglas Fir, Red oak, compression parallel to the grain, Maximum crushing strength, Modulus of elasticity and fiber stress

Category: Research Notes
File size: 220 kb(s)

Abstract: An investigation of effects of adhesive formulation and age was made on butt joints of slash pine (

Pinus elliottii

Category: Research Notes
File size: 375 kb(s)

Abstract: Within the limits of the study, high moisture content in the wood and high cutting speed resulted in higher loads on the roller bar than when cutting wood having moderate moisture content at slow cutting speed. In general, veneer cut with high loads on the roller bar was thinner and weaker in tension perpendicular to the grain than veneer cut with moderate loads on the roller bar.

Keywords: moisture content, speed of cut, rotary-cut veneer, loblolly pine,yellow-poplar, southern pine

Category: Research Notes
File size: 395 kb(s)

Abstract: Presents a linear solution for determining the effect of combined axial and lateral loads under which a cylindrical sandwich shell will buckle. The facings of the sandwich cylinder are treated as homogeneous isotropic cylindrical shells and the core as an orthotropic elastic body. The characteristic determinant that represents the solution to the problem is solved numerically. Curves are given that show how the buckling load changes as the parameters of the problem change.

Keywords: elastic stability, sandwich shells, lateral loads, buckling, Mathematical Analysis, Prebuckling Stresses, equations of equilibrium

Category: Research Notes
File size: 284 kb(s)

Abstract: Shrinkage, specific gravity, and hardness of two shipments of silk-oak (Grevillea robusta) from Hawaii were evaluated to provide basic information pertinent to the use of the wood for cabinet and furniture purposes.

Keywords: Hardness, Density, Shrinkage characteristics, Silk-Oak, Hawaii

Category: Research Notes
File size: 50 kb(s)

Abstract: The Forest Products Laboratory has developed a laminated diving board that has shown excellent performance characteristics. This board has given long, economical service under the severe moisture hazards and heavy service conditions such as found at public swimming places. The adhesive used is of the fully waterproof synthetic-resin type, which requires no protection from moisture. The board is made from narrow strips of seasoned lumber and is fully equivalent to the premium-quality one-piece boards made from selected wide and thick stock.

Keywords: LAMINATED DIVING BOARD, performance characteristics, waterproof synthetic-resin,

Category: Research Notes
File size: 371 kb(s)

Abstract: The wood-base fiber panel materials are a part of the rapidly evolving technology based on converting lignocellulose to fiber and reconstituting the fiber into large sheets and panels. While some equipment and techniques used are the same as for producing paper, there are enough differences in techniques used and other requirements for manufacture that a separate treatment of the subject is warranted. This research note describes the various requirements for raw materials and equipment, describes various steps in manufacture, and presents summaries of important strength and physical properties of insulating board, medium-density building fiberboard, and hardboard.

Keywords: INSULATING BOARD, HARDBOARD, STRUCTURAL FIBERBOARDS, insulating board, medium-density fiberboard, and hardboard

Category: Research Notes
File size: 306 kb(s)

Abstract: The exact location of failure was determined in butt joints of slash pine (

Pinus elliottii

Category: Research Notes
File size: 219 kb(s)

Abstract: A major loss sustained by small mills results from inaccurately cut lumber. Such lumber sells only at reduced prices and encounters stiffer sales resistance than lumber from the more accurately cutting band mills. A less apparent loss is the excessive loss of material that results from inaccurate cutting.

Keywords: uneven tension, worn collars, worn bearings

Category: Research Notes
File size: 89 kb(s)

Abstract: Plywood is manufactured by bonding thin sheets of wood (veneers) together with adhesives in such a way that the mechanical and physical properties of the wood are redistributed. This manufacture of plywood requires special equipment, knowledge, and technique. Important steps in the process of making flat plywood are outlined here, as well as information on types and grades and some properties of plywood. The information is based upon observations of factory practice and upon extensive experiments at the Forest Products Laboratory.

Keywords: characteristics, flat plywood, veneer, adhesives

Category: Research Notes
File size: 130 kb(s)

Abstract: The moisture content of wood will change with changes in the conditions under which it is used. To give best service, the wood should be installed at a moisture content close to the midpoint between the high and low values it will usually attain in use. This report presents recommendations that will enable the user to select thepreferable moisture content for wood used under various conditions.

Keywords: Moisture content, Shrinking, Swelling

Category: Research Notes
File size: 1330 kb(s)

Abstract: Experimental work was undertaken to investigate the extent and magnitude of deterioration that can occur in typical plywood-to-lumber glue joints subjected to stresses resulting from changes in the moisture content of the wood, and to compare the performance of a somewhat flexible or deformable adhesive to that of a rigid adhesive in these joints.

Keywords: Moisture Content Change Cycle, Lumber and Plywood Orientation, Adhesive Thickness, Resorcinol-resin panels, Exposure Cycle

Category: Research Notes
File size: 251 kb(s)

Abstract: Wood has always been a highly useful material to the farmer. In the early days the forests had to be partially cleared to make room for his crops. Wood was the only readily available material to which he could turn for his shelter, his fuel, and his tools. While other materials are now available to the farmer, wood continues to have an important part in agriculture because of its favorable cost, strength, weight, beauty, working characteristics, insulation value, and availability.

Keywords: Preservative treatment, farm, strength, weight, beauty, working characteristics, insulation value, and availability.

Category: Research Notes
File size: 796 kb(s)

Abstract: Needs for Nondestructive Testing in the Forest Products Industries held on May 14 and 15, 1964, at the Forest Products Laboratory. The purpose of this meeting was to bring together about 30 representatives of the various forest products industries and a few affiliated research and educational institutions to discuss and define industry needs for nondestructive testing. The necessity for such a meeting was made clear in the Symposium on Nondestructive Testing of Wood held at this Laboratory in October 1963.1 The meeting was a direct result of the recommendation made at the close of that Symposium, pointing out that effective development of nondestructive testing within the forest products industries is dependent on having the needs for such testing better defined than has been done to date.

Keywords: NONDESTRUCTIVE TESTING, Structural Lumber, Poles and Piling, Laminated Timber, Plywood

Category: Research Notes
File size: 2443 kb(s)

Abstract: This Research Note presents the results of a study in photographic techniques that are useful in illustrating defects and indications of defects in logs and lumber. The techniques described were found to be the best of all those studied, and include those for use under well-controlled photographic conditions in a laboratory and those for use in a sawmill yard where variable and less advantageous conditions prevail. This study will be of particular interest to persons who are developing or preparing log-grade training aids.

Keywords: Photographing, Log and lumber Characteristics, panchromatic film

Category: Research Notes
File size: 90 kb(s)

Abstract: One of the imported woods that is finding increasing use for specific purposes is ramin (

Gonystylus

Category: Research Notes
File size: 955 kb(s)

Abstract: The owner of a small quantity of green lumber or logs is often confronted with seasoning it to a state of dryness suitable for use in furniture, wood carving, or other handiwork. He cannot follow the practice of commercial mills, which employ dry kilns for the purpose. because kilns are too costly. On the other hand, air seasoning outdoors usually does not dry lumber sufficiently for such uses, although it is sufficient for structures that will be used outdoors.

Keywords: Seasoning, green lumber, checking, warping

Category: Research Notes
File size: 70 kb(s)

Abstract: Requests are frequently received by the Forest Products Laboratory to examine warped plywood, veneered table tops, or similar products, to explain the cause of the warping, and if possible to suggest measures to remedy the difficulty.

Keywords: Warping, Twisting, Cupping, plywood, veneer

Category: Research Notes
File size: 261 kb(s)

Abstract: Methods useful in detecting and studying microbiological deterioration of wood are discussed. They concern aspects of wood microtechnique fundamental to the execution of microscopical examinations of decayed wood, isolation and culture of wood-destroying microorganisms, diagnosis of decay and discolorations, and testing of preservatives and natural decay resistance. Special equipment developed for the study of wood-destroying fungi is also discussed.

Keywords: microbiological deterioration, toughness, weight loss, Rough Surface, smooth surface

Category: Research Notes
File size: 402 kb(s)

Abstract: Evaluations of several mechanical and physical properties were conducted on specimens from five yagrumo hembra (Cecropia peltata) trees from Puerto Rico. With the exception of toughness and modulus of elasticity in both bending and compression parallel to grain, these specimens were lower in specific gravity and in strength properties than material reported previously. Although the specific gravity of the new material averaged about twice that of balsa, a wide range of specific gravity was evident and material at the lower part of the range could possibly be used as a substitute for balsa. Dense yagrumo hembra resembles North American black cottonwood in both specific gravity and mechanical properties. Total shrinkage from green to the ovendry condition was not excessive although the ratio of tangential to radial shrinkage appears about twice that characteristic of most species.

Keywords: mechanical and physical properties, Yagrumo Hembra,

Category: Research Notes
File size: 88 kb(s)

Abstract: From the earliest days of exploration and colonization in tropical America, Spanish-cedar has been one of the most important timber trees of the area. The wood became an article for the export trade during the 1800’s when the cigar industry demanded the use of Spanish-cedar for packing cigars. These fragrant boxes were commonplace before rising costs in the 1930’s finally forced the cigar industry to turn to paperboard or less expensive containers manufactured from soft native lumber. Spanish-cedar remains to this day as one of the most valued trees for local use in Latin America. In the areas of growth the tree and wood are generally referred to as cedro.

Keywords: SPANISH -CEDAR, diffuse-porous, ring-porous, Mechanical Properties, Working Characteristics

Category: Research Notes
File size: 188 kb(s)

Abstract: Presents series of standard terms for describing specific gravity, shrinkage, bending and compressive strength, hardness, shock resistance, and stiffness of the various species of wood as developed by the U. S. Forest Products Laboratory.

Keywords: descriptive terms,large shrinkage, moderately heavy, moderately stiff, moderately hard, shock resistance, bending, compression

Category: Research Notes
File size: 870 kb(s)

Abstract: Present design procedures for a continuous wood beam use a design moment (negative moment over interior support) calculated by the method of three moments. The design of a reinforced-concrete continuous beam uses a reduced span and correspondingly reduced moment to account for the width of support. The purpose of this study was to determine whether the design moment (and hence the stress) over the support of a three-span continuous wood beam could be reduced.

Keywords: stress distribution, three-span continuous wood laminated beam, Moisture Control, Modulus of Elasticity

Category: Research Notes
File size: 425 kb(s)

Abstract: Thick particleboards made from pulp chip cores were evaluated as possible roof decking material. Several fabrication variables and various kinds and combinations of face construction were investigated. Results were favorable for many of the combinations tried. Possibilities are good that a properly made particleboard, 1-3/4 inches thick, can be used for spans of 48 inches. Results are presented of evaluations of stiffness and strength in flexure, resistance to accelerated aging, internal bond strength, and dimensional changes from ovendry to soaked conditions.

Keywords: particle boards, pulp chip cores, roof decking, mechanical properties, physical properties

Category: Research Notes
File size: 245 kb(s)

Abstract: Acrylonitrile (CH₂ = CH -CN) was reacted with unbleached southern pine kraft linerboard and bleached southern pine kraft cardstock to determine the effect of this treatment on compressive strength and dimensional stability. A sweetgum kraft pulp was treated similarly before and after bleaching and the paper-making qualities ,of the treated pulps were evaluated.

Keywords: Kraft paperboards, Kraft pulp, Acrylonitrile, compressive strength, Dimensional stability

Category: Research Notes
File size: 91 kb(s)

Abstract: Pacific madrone (

Arbutus menziesii Pursh

5

1

Category: Research Notes
File size: 126 kb(s)

Abstract: This report gives information on the preparation of wood fuel from wood residues and other wood raw materials. Types of wood fuel discussed are cordwood, stovewood, slabwood, kindling, chips, hogged fuel, sawdust and shavings, bark, charcoal, alcohol, and briquets. Related information is given on types of machinery for preparing wood fuel and on possible markets for its sale.

Keywords: Wood fuel, residues

Category: Research Notes
File size: 114 kb(s)

Abstract: Possible lines of manufacture and general requirements are summarized for various wood products from small sawmills and woodworking plants.

Keywords: SMALL SAWMILLS, WOODWORKING PLANTS, Business Factors, Lines of Manufacture, Products and Methods of Manufacture

Category: Research Papers
File size: 42639 kb(s)

Abstract: This Research Note presents data showing how the volume and value of lumber grade yields, from mill-run hardwood logs of a given species, diameter, and sawlog grade, vary with the withdrawal of veneer quality logs. A total of 8,500 log diagrams for No. 1 and No. 2 grade sawlogs were regraded on the basis of two arbitrarily selected veneer log grades. The tabulated data can serve as a guide to sawmill owners in deciding whether or not to sellveneer logs, and whether such sale would result in a less salable mix of lumber grades.

Keywords: Mill Run Hardwood, Sawlog Lumber Grade Yields

Category: Research Papers
File size: 1347 kb(s)

Abstract: This report describes three experimental techniques for determination of specific mechanical properties of the adhesive layer between two pieces of lumber. The properties are stress relaxation, modulus of rigidity, and creep. They are measured in a small joint segment when loaded in compression shear so that the strain in the adhesive film can be measured at each level of stress without the usual complications of strain in the wood itself. The apparatus and procedures are described for each determination, but no actual test data are reported.

Keywords: Mechanical behavior, Flexible structural adhesives, stress relaxation, modulus of rigidity, creep

Category: Research Papers
File size: 1695 kb(s)

Abstract: Batch-type microreactors (about 1/40 milliliter of reactants) were used to measure furfural yields from acidified xylose solutions containing sodium xylenesulfonate. Initialxylose concentrationwas 0.666 molar. Two levels of sulfuric acid catalyst were used, 0.05 and 0.2 molar, while the sodium xylenesulfonate concentration ranged from 0 to 1.68 molar (close to saturation at room temperature). The reaction temperatures were 150°, 200°, and 240° C. It was found that presence of the salt did not affect the quantity of furfural produced, but greatly increased the rate of formation. The regular increase in rate of furfural formation was directly related to the increase in the rate of xylose decomposition, and furfural yields for all salt and acid concentrations at a given temperature were uniquely described by the xylose half-life.

Keywords: Furfural Yield, Sodium, Dimethylbenzenesulfonate, sulfuric acid

Category: Research Papers
File size: 1097 kb(s)

Abstract: Racking evaluations of wood-frame wall panels for dwellings and similar structures indicated that the following considerations were important in improving the rigidity and strength
1. If a saving in material is desired, decreasing the size of the studs was found to be better than increasing the spacing between studs in walls sheathed horizontally with lumber.
2. Although the value of diagonal wood sheathing was evident, excellent performance was also attained with plywood, fiberboard, and hardboard when used in 4-by 8-foot and longer sheets placed vertically with perimeter nailing.
3. Full-length let-in bracing at a 45°angle proved to be the best type of bracing. An exterior wall covered only with siding can be improved more than four-fold by the use of a 1-by 4-inch let-in brace.
4. Increasing the size or number of fastenings for sheathing made a substantial improvement.
5. A plaster finish was excellent.
6. Framing with medium-density softwood was better than with low-density softwood. However, this difference could be compensated by using larger or more nails in the sheathing.
7. Seasoned studs are recommended for rigid and strong walls. The use of unseasoned studs materially reduced the rigidity and strength of the wall after seasoning in place.

Keywords: framed walls, rigidity, strength, wood framed walls,

Category: Research Papers
File size: 932 kb(s)

Abstract: The heats of combustion of the volatile pyrolysis products released up to various stages of volatilization from untreated and chemically treated ponderosa pine were determined. This heat of combustion of the volatile products was calculated as the difference between the heat of combustion of the original unpyrolyzed (treated or untreated) wood and the heat of combustion of the char residue left after partial pyrolysis.

Keywords: Combustion, Pyrolysis, Fire-retardant-treated, Ponderosa Pine

Category: Research Papers
File size: 5436 kb(s)

Abstract: Numerous Laboratory and exposure tests have shown that sandwich wall panels of nominal thicknesses and con-structions can be satisfactorily used for housing construction. In addition to initial strength tests, exposure of test panels for 15 years in the Forest Products Laboratory’s experimental unit have indicated that loss in stiffness and strength is insignificant for certain com-binations of materials. The wall panels made of resin-impregnated paper cores and plywood facings have demonstrated excellent per-formance, based on retention of stiff-ness and strength, However, other com-binations of facings and paper cores have resulted in only fair to moderate performance.

Keywords: Sandwich panels, lightweight construction,

Category: Research Papers
File size: 707 kb(s)

Abstract: Xylose decomposition rate was measured in solutions containing 10 grams xylose per 100 milliliter, 0.05-0.2 molar sulfuric acid, and 0-1.563 molar 2,4 dimethylbenzenesulfonate over the temperature range 120° - 150° C. The observed specific rate was found to be exponentially related to the ionic strength and of the magnitude expected for a reaction involving an ion and an uncharged molecule. However, the primary salt effect exhibits a marked variation with catalyst concentration which is not satisfactorily explained. It is, perhaps, due to incomplete dissociation of xylenesulfonic acid or to the presence of concomitant reactions. The latter explanation is supported in part by the presence of base-catalyzed reactions in the salt-free solutions.

Keywords: kinetics, hemicellulose, lignin, xylose

Category: Research Papers
File size: 984 kb(s)

Abstract: Wall panels used in construction of a prefabricated house, built in 1937, were removed in 1962 to determine their performance characteristics after 25 years’ service. The panels were evaluated for stiffness and bending strength, and the glue joints in the plywood and between the plywood and the framing members were evaluated for shear strength. Replacement panels. placed in the prefabricated house in 1962, were evaluated to equivalent design loads of 20 pounds per square foot prior to being placed in the house. Panels of a construction similar to the replacement panels were evaluated to failure.

Keywords: panel stiffness, design values, glue joints

Category: Research Papers
File size: 671 kb(s)

Abstract: Handsheets of various commercial and experimental papermaking pulps were ovendried in special drying frames that controlled the amount of shrinkage. Unstretched handsheets and those stretched predetermined amounts were dried with various allowances for shrinkage and tested in tension to determine the influence of restraint during drying on the strength, modulus of elasticity, and strain to failure.

Keywords: Effects of wet pressing, effect of restraint, tensile strength-density, moisture content at time of restraint, permanence of effects of restraint

Category: Research Papers
File size: 632 kb(s)

Abstract: Eight coniferous and two deciduous tree species common to Wisconsin were evaluated for wood density. Overall core and tree specific gravity means for species are presented, as well as means and variation by diameter class within Forest Survey Units. The northeastern survey unit of the State had significantly higher core specific gravity for six species. For four other species the values for this area were higher but not significantly. No other trends were found.

Keywords: Specific gravity, wood density, increment core, diameter class, species

Category: NewsLine
File size: 772 kb(s)

Abstract: 

Standing Up to Mother Nature: Wood-frame building holds its own against the world's largest earthquake test
FPL Scientist Profile: Chuck Frihart, Research Chemist
Decoding Decay Fungi through Genome Sequencing
Wood You Believe
Upcoming Events


Keywords: frame building,earthquake,fungi,genome sequencing

Category: TMU - Woody Biomass Grant Utilization Program
File size: 281 kb(s)

Abstract: Eligibility, Award Information and Criteria for the 2010 Woody Biomass Utilization Utilization Grant Program.

Keywords: Woody biomass grant 2010 Eligibility Award Information Full Application, Prelimary application

Category: TMU - Woody Biomass Grant Utilization Program
File size: 96 kb(s)

Abstract: Full application for the 2010 Woody Biomass Utilization Utilization Grant Program. Full application shall be post marked by April 2, 2010 and received no later than 5:00 PM Central Standard Time on April 9, 2010.

Keywords: Woody biomass grant 2010 Eligibility Award Information Full Application, Prelimary application

Category: TMU - Woody Biomass Grant Utilization Program
File size: 56 kb(s)

Abstract: Pre-application for the 2010 Woody Biomass Utilization Utilization Grant Program. Must be postmarked by November 20, 2009 and received no later than 5:00 PM Central Standard Time on November 27, 2009.

Keywords: Woody biomass grant 2010 Eligibility Award Information Full Application, Prelimary application