Category: Forest Products Utilization Technical Reports
Unit: Pending
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
Unit: Economics and Statistics Research - FPL4851
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Performance Enhanced Bioploymers - FPL4707
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Durability and Wood Protection Research - RWU4723
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Economics and Statistics Research - FPL4851
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Durability and Wood Protection Research - RWU4723
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Performance Enhanced Bioploymers - FPL4707
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Analytical Chemistry and Microscopy Laboratory (ACML) - ACML
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Pending
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
Unit: Pending
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Economics and Statistics Research - FPL4851
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
Unit: Economics and Statistics Research - FPL4851
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Economics and Statistics Research - FPL4851
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
Unit: Engineered Composites Science - FPL4706
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
Unit: Durability and Wood Protection Research - RWU4723
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
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
Unit: Engineered Composites Science - FPL4706
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
Unit: Engineered Composites Science - FPL4706
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
Unit: Engineered Composites Science - FPL4706
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
Unit: Engineered Composites Science - FPL4706
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
Unit: Economics and Statistics Research - FPL4851
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
Unit: Economics and Statistics Research - FPL4851
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
Unit: Coalition for Advanced Wood Structures - CAWS
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: Research Papers
Unit: Economics and Statistics Research - FPL4851
File size: 2090 kb(s)

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: Journal Articles
Unit: Institute for Microbial and Biochemical Techology - FPL4712
File size: 254 kb(s)

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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Institute for Microbial and Biochemical Techology - FPL4712
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
Unit: Coalition for Advanced Wood Structures - CAWS
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
Unit: National Center for Wood Transportation Structures - NCWTS
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
Unit: Forest Products Technology Marketing Unit (TMU) - TMU
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
Unit: Forest Products Technology Marketing Unit (TMU) - TMU
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
Unit: Durability and Wood Protection Research - RWU4723
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Engineered Composites Science - FPL4706
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
Unit: Durability and Wood Protection Research - RWU4723
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
Unit: Durability and Wood Protection Research - RWU4723
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Economics and Statistics Research - FPL4851
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Analytical Chemistry and Microscopy Laboratory (ACML) - ACML
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
Unit: Fiber and Chemical Sciences Research - FPL4709
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
File size: 306 kb(s)

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

Pinus elliottii

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

Abstract: Pacific madrone (

Arbutus menziesii Pursh

5

1

Category: Research Notes
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Pending
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
Unit: Office of Communications
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
Unit: Forest Products Technology Marketing Unit (TMU) - TMU
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
Unit: Forest Products Technology Marketing Unit (TMU) - TMU
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
Unit: Forest Products Technology Marketing Unit (TMU) - TMU
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

Category: General Technical Reports
Unit: Economics and Statistics Research - FPL4851
File size: 2020 kb(s)

Abstract: A spreadsheet-based model, LSY (Log-sort Yard Cash Flow Analysis), has been constructed to aid in the pre-feasibility and financial feasibility analysis of log-sort yards. It is meant to be referred to concurrently with this documentation and is available for downloading at no cost from the Forest Products Laboratory.s website at: http://www.fpl.fs.fed.us/documnts/fplgtr/fpl_gtr184/LSY3.01.xls.

Keywords: Log-sort yard; financial feasibility; small-diameter; economics; break-even analysis; . cost analysis; decision support

Category: Agricultural Handbook
Unit: Pending
File size: 212 kb(s)

Abstract: Technical Notes and Glossary of Housing Terms

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 529 kb(s)

Abstract: The construction of a house is a complex process and requires detailed planning. It is often advisable to engage the services of an architect or experienced builder to assist in the process.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 670 kb(s)

Abstract: Tasks related to site preparation and construction of footings and foundations, including a retaining wall, are discussed in this chapter.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 1410 kb(s)

Abstract: The sections contained in this chapter address the tasks related to erecting the structural framing for the house and creating an enclosure that provides some degree of protection from the elements.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 1040 kb(s)

Abstract: The topics discussed in this chapter are specific tasks related to completing the construction of the shell of the house. Their order of presentation does not necessarily reflect the sequence of performance.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 505 kb(s)

Abstract: The topics discussed in this chapter include a variety of specialty features that are included in some but not all home construction plans.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 442 kb(s)

Abstract: Sections in this chapter discuss the work to be done inside the house after the shell is complete.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 240 kb(s)

Abstract: A variety of moldings are available to provide a finished trim around doors and windows and at the intersection of walls with the floor or the ceiling. Typical molding patterns are shown in figures 171 to 174. Moldings that receive a natural finish are often oak or other hardwood species. The usual softwood molding is ponderosa pine. It is used where the finish is to be painted, but sometimes it is stained and given a natural finish. Molded particleboard with a wood grain vinyl overlay is also used in some cases.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 410 kb(s)

Abstract: Wood used in conditions where it is always dry, or even where it is wetted briefly and then redries rapidly, does not decay. However, all wood and wood products used in construction are susceptible to decay if kept wet for long periods under temperature conditions favorable to the growth of decay organisms. Most of the wood used in a house is not subjected to such conditions. There are places where water can work into the structure, but such places can be protected. Protection is accomplished by methods of design and construction, by use of suitable materials, and in some cases by using treated material.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: Agricultural Handbook
Unit: Pending
File size: 47 kb(s)

Abstract: This handbook presents sound principles for woodframe house construction and suggestions for selecting suitable materials to assist the construction of a good house. The organization reflects the general progression of activity in building a wood-frame house, from initial conception to completed structure. Chapter 1 describes matters that should be considered or dealt with before beginning construction. Chapters 2-4 describe steps in laying the groundwork, framing and closing in, and completing the shell, which are usually taken one after another in the order presented. Chapters 5-7 describe later tasks that can often be done in some order other than presented. Chapter 8 discusses special topics often associated with wood-frame construction. Technical notes, annotated list of suggestions for additional reading, and glossary are provided.

Keywords: Wood-frame, house, construction, building materials, building codes, foundations, framing, siding, roofing, paints and stains, energy conservation, noise control, decay, termites, maintenance and repair.

Category: TMU - Woody Biomass Utilization Status Report
Unit: Forest Products Technology Marketing Unit (TMU) - TMU
File size: 44 kb(s)

Abstract: Status report from TMU (Technology Marketing Unit) that summarizes successfull American Recovery and Reinvestment Act (ARRA) and Woody Biomass Utilization Group (WBUG) activities.

Keywords: American Recovery and Reinvestment Act ARRA Woody Biomass Utilization Group WBUG economic stimulus package Biomass removal Biomass processing

Category: Research In Progress
Unit: National Center for Wood Transportation Structures - NCWTS
File size: 1006 kb(s)

Abstract: Since 1988, the USDA Forest Service Wood in Transportation Program involved research through the Forest Products Laboratory (FPL) in Madison, WI, and demonstration and technology transfer through the National Wood in Transportation Information Center in Morgantown, WV. This national program included all types of wood transportation structures, including vehicle, pedestrian and railroad bridges, marine facilities, and noise barriers. The program funding ended in FY 2004, leaving significant voids in research capability, technology transfer, and research assistance. To fill this need, an effort was initiated to re-establish a national center for wood transportation structures to provide leadership in these areas to governmental agencies, industry, and research institutions.

Keywords: wood bridges; wood transportation center; timber bridges

Category: Demonstration in Progress
Unit: National Center for Wood Transportation Structures - NCWTS
File size: 721 kb(s)

Abstract: When properly designed and protected from elements such as water, insects, and fire, timber is a structurally capable, cost-effective, and aesthetically pleasing material suitable for many structural applications. However, when not properly designed or protected, timber structures become susceptible to deterioration, which may result in decreased structural capacity. As a result of accelerated and repeated deterioration of wearing surfaces on timber bridges (for example, transverse cracking along deck panel joints), the perception of these structures has consistently remained less than acceptable, despite their excellent structural performance. The unacceptable performance of timber bridge wearing surfaces, typically constructed of asphalt, has raised concerns regarding performance of the underlying superstructure and its effect on the wearing surface performance. For timber bridges to be an acceptable and competitive design alternative for bridge owners and designers, timber bridges and their wearing surfaces must be designed so that deterioration and maintenance are minimized.

Keywords: timber; deck; wearing surface; differential deflection; design; details

Category: Research In Progress
Unit: National Center for Wood Transportation Structures - NCWTS
File size: 1080 kb(s)

Abstract: According to the Federal Highway Administration (FHWA), approximately 880 historical covered timber bridges remain in the United States. These magnificent bridges were built with several types of heavy timber trusses that were developed during America's first century (1776-1876). These examples of early-American bridge building traditions are mostly located in the northeastern United States but are also found in significant numbers in the Pacific Northwest. Pennsylvania, Ohio, Indiana, Vermont, and Oregon have the largest inventories of surviving covered timber bridges. Efforts to preserve these structures have largely been driven by local fundraising efforts until recently. In 2000, FHWA established a National Program for the Historic Preservation of Covered Timber Bridges. The program provides grant funding opportunities for states to protect, restore, preserve, or rehabilitate their historical covered timber bridges. These bridge preservation efforts are guided by the Secretary of Interior's Guidelines for Historic Preservation.

Keywords: covered bridge; load testing; improved ratings; live-load testing; bridge performance

Category: Journal Articles
Unit: Fiber and Chemical Sciences Research - FPL4709
File size: 546 kb(s)

Abstract: SilviScan uses X-ray transmission measurements along with optical imaging to profile tracheid dimensions and wood density in specially prepared cores. These measurements are useful for predicting the properties of pulp and paper generated from the wood. SilviScan measurements are resolution-limited by the width of the X-ray beam, which was 50 m in the present study. Trees with growth rings smaller than 200 m have latewood regions too small to measure without sampling adjacent earlywood, producing erroneous latewood measurements. For these suppressed-growth trees, we developed an all-optical imaging approach called Ring Profiler to contrast with SilviScan. Ring Profiler uses higher magnification than SilviScan, allowing direct measurement of tracheid wall thicknesses. Ring Profiler showed that SilviScan overestimated latewood tracheid radial diameters by as much as 100% in growth rings under 200- m width. It also showed that SilviScan underestimated density of suppressed-growth latewood by 15-20%. Use of higher magnification limits Ring Profiler’s measurements to fewer tracheids than SilviScan’s (3% as many in the present study). Ring Profiler lacks the ability of SilviScan to measure microfibral angle by means of X-ray diffraction, and density measurement by Ring Profiler is indirect. Otherwise, all dimensional information provided by SilviScan can be generated at higher resolution using widely available optical imaging technology.

Keywords: SilviScan, optical imaging, tracheid dimensions, wood density

Category: Journal Articles
Unit: Fiber and Chemical Sciences Research - FPL4709
File size: 116 kb(s)

Abstract: Two new methods based on FT-Raman spectroscopy, one simple, based on band intensity ratio, and the other, using a partial least-squares (PLS) regression model, are proposed to determine cellulose I crystallinity. In the simple method, crystallinity in semicrystalline cellulose I samples was determined based on univariate regression that was first developed using the Raman band intensity ratio of the 380 and 1096 cm-1 bands. For calibration purposes, 90% crystalline Whatman CC31 and cellulose mixtures with crystallinities in the range 12-72% were used. When the intensity ratios were plotted against the theoretical crystallinities of the mixtures the plot showed a linear correlation (correlation coefficient R2 = 0.995). Standard error calculated from five replicate Raman acquisitions indicated that the cellulose I Raman crystallinity model was reliable. Crystallinities of these cellulose mixtures were also calculated from x-ray diffractograms but these generated a correlation that was inferior compared to the one based on the Raman model. Additionally, using both Raman and x-ray techniques, sample crystallinities were determined from partially crystalline cellulose samples that were generated by grinding Whatman CC31 in a vibratory mill. The two techniques showed significant differences. In contrast to x-ray diffractograms, evidence of significant differences was present between the Raman spectra of low crystallinity celluloses and indicated that Raman spectroscopy was better suited to investigate differences between such samples.

Keywords: FT-Raman Spectroscopy, (PLS) partial least-squares regression model, cellulose I crystallinity

Category: Journal Articles
Unit: NRS Units
File size: 266 kb(s)

Abstract: This chapter provides a brief synopsis of previous studies on the ecology of agaric decomposers that form litter 'mats' in tropical forests, augmented by data from temperate forest studies. Description of several experiments in tropical forests of the Luquillo Mountains in Puerto Rico is included. These studies showed higher rates of mass loss in leaves that were decomposed on basidiomycetemycelia(i.e.,white-rot) than in the absence of basidiomycetes.

Keywords: Distribution, Mat-forming Saprobic Basidiomycetes, tropical forests, movement of litter mats

Category: Journal Articles
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
File size: 480 kb(s)

Abstract: Eocene terrestrial strata of central Oregon contain abundant and well-preserved fossil woods that are important for understanding past floristic diversity, forest structure, and climate. In addition to the remarkably diverse and well-preserved Middle Eocene wood assemblage of the Clarno Nut Beds in the type area of the Clarno Formation in the John Day basin, there are well-preserved diverse Late Eocene wood assemblages from the vicinity of Post in the Crooked River Basin. The Post assemblages discussed herein share some genera with the Nut Beds flora (Acer, Cercidiphyllum, Quercinium, Ulmus), but also include some new elements that remain to be described in detail, including woods referable to the families Anacardiaceae, Fagaceae, Hamamelidaceae, and Juglandaceae. Comparison of the middle Eocene Nut Beds woods to the younger Post woods documents changes in climate, with the Post assemblages indicating increasing seasonality and an increase in deciduousness.

Keywords: Eocene wood, Central Oregon, Crooked River Basin, Acer, Cercid iphyllum, Quercinium, Ulmus

Category: Journal Articles
Unit: Pending
File size: 275 kb(s)

Abstract: A hybrid poplar, Populus Tristis No.1, grown under short-rotation intensive culture, was investigated as a possible raw material source for the manufacture of hardboard. All aboveground material was chipped, and a portion of the chips was upgraded with vacuum airlift segregation to remove some fines and bark. Debarked aspen stemwood was used as a control. All chips were fiberized in a small pressurized singledisk refiner, and medium-and high-density hardboards were made from the pulps by both the wet-and dryforming processes. Two resin contents were used in each type of hardboard manufactured. Hardboards were evaluated for strength properties and dimension change, and test results were analyzed statistically. Results indicate that intensively cultured Populus raw material is suitable for manufacturing hardboards.

Keywords: Hardboard, short-rotation, Populus, Tristis No.1, Debarked Aspen stemwood, fiberized

Category: Journal Articles
Unit: Engineering Mechanics and Remote Sensing Laboratory (EMRSL) - EMRSL
File size: 911 kb(s)

Abstract: In an effort to encourage the development of value-added engineered applications for small-diameter round timber, research is being conducted at the US Forest Products Laboratory to develop and verify design guidelines for connections with specific application to round timbers. The objective of this study is to provide potential users with a number of viable connection options applicable to the fabrication of engineered, round-timber structural components and systems. Target uses include trusses, built-up flange beams, and space frames. This article presents information on a mortised steel-plate connection fabricated using power-driven nails in 150-mm-dia ponderosa pine. The article discusses methods used to determine per nail load capacity and to develop design procedures that incorporate that value in the determination of a multinail connection design value. These connections offer the advantage of low labor and material cost, ductile failure modes, and strengths in the range of 4.7 kN/nail. The failure of the connections was mode III nail failure and wood block shear failure. Joints that failed in block shear appeared to have roughly the same strength as those that failed from nail yield. The National Design Specification yield model for nails provides accurate predictions of joint capacity for nail yield-type failures and overestimates strength of joints that exhibit wood failure. Block shear capacity can be estimated on the basis of clear-wood strength and effective tensile and shear area of the connection.

Keywords: Small-diameter round timber, connections, power-driven nails, design value, failure mode.

Category: Journal Articles
Unit: Pending
File size: 254 kb(s)

Abstract: that the predominant species in aqueous alkali is anthrahydroquinone (AHQ), and the corresponding semiquinone has only transient existence at best. Reaction of AHQ with the quinone methide (QM) derived from guaiacylglycol-ß-guaiacyl ether[1-(3-methoxy-4-hydroxyphenyl)-2-(2-methoxyphenoxy/ethanol](I)resulted in theformation ofanintermediateAHQ/QM adduct, 1-(3-methoxy-4-hydroxyphenyl)1-(10-hydroxyanthracen-9-one-10-yl)-2-(2 -methoxyphenoxy) ethane. ¹H NMR spectroscopy of the adduct and its derivatives is consistent with the proposed structure. Further confirmation was provided by an independent synthesis of a derivative of the adduct. Treatment of the adduct with alkali at elevated temperature gave the same cleavage fragments (guaiacol and 2-methoxy-4-vinylphenol) which were formed upon digestion of I in soda-AHQ pulping liquor.

Keywords: Soda pulping, Anthraquinone, Anthrahydroquinone, lignin, Delignification

Category: Journal Articles
Unit: Fiber and Chemical Sciences Research - FPL4709
File size: 137 kb(s)

Abstract: In this study, Raman spectroscopy was used to investigate the spatial distribution of cellulose nanocrystals (CNCs) in extruded polypropylene (PP) filaments. Raman maps, based on cellulose and PP bands, obtained at 1 micron spatial resolution showed that the CNCs were aggregated to various degrees in the PP matrix. Of the three composites analyzed, two showed clear existence of phase separated regions - Raman images with PP strong and cellulose absent or vice versa. For the third composite, the situation was slightly improved but a clear transition interface between the PP-abundant and CNC-abundant regions was observed indicating that the CNC remained poorly dispersed. Nevertheless, tensile and modulus tests of the composites indicated up to 10% improvement compared to PP alone.

Keywords: Mapping cellulose, nanocrystal-polypropylene composite, CNC. PP, PP-abundant, CNA-abundant

Category: Journal Articles
Unit: Fiber and Chemical Sciences Research - FPL4709
File size: 182 kb(s)

Abstract: Near-IR surface enhanced Raman scattering (SERS) spectra of spruce Wiley milled-wood (WMW) and milled-wood lignin (MWL) adsorbed on the silver nanoand micro-particles were obtained recently in our laboratory. When the SERS spectra of wood and MWL were compared they were found to be almost identical which suggested that the signals from the carbohydrate components were absent in the WMW SERS spectrum. This was also supported by the fact that no SERS spectrum of cellulose could be obtained under these conditions. Therefore, lignin could be selectively studied in the presence of other wood constituents without separation. Some general characteristics of the lignin SERS spectrum are described. The SERS technique was also found to be highly sensitive because only a very small amount of the sample is needed. For MWL, SERS and normal Raman spectra were compared and it was determined that significant spectral changes were present. Raman spectral changes and x-ray photoelectron spectral analysis of the MWL SERS sample provided evidence that showed that lignin is strongly adsorbed on silver. This nano- and micro-particle based lignin analysis technique is expected to make a significant contribution to investigating lignin in various lignocellulosic materials.

Keywords: Raman Spectroscopy, Lignin analysis

Category: Journal Articles
Unit: Performance Enhanced Bioploymers - FPL4707
File size: 670 kb(s)

Abstract: The aim of this study was to investigate safer, more inexpensive chemicals derived from sodium silicate that can be used to protect wood against fungal degradation. Desiccant and surfactant properties of sodium silicate-derived products have been used since the early 19th century and may find application for wood decay protection. In our study, wood was impregnated with 19.5% sodium silicate and acidified with 2.5% phosphoric acid for 2 da to produce polysilicic acid. After 2-wk daily water leaching, leached specimens had 0.2% weight loss by a brown-rot fungus, Gloeophyllum trabeum, and weight losses of 3.4 - 5.2% by a white-rot fungus, Trametes versicolor. The control had 32.2 and 30.2% weight losses by G. trabeum and T. versicolor, respectively. Energy-dispersive X-ray analysis showed that polysilicic acid deposited mainly in the cell lumens. Exposure at 90% RH showed that polysilicic acid-treated loblolly pine or sweet gum that had been water-leached with 22 - 34% chemical retention absorbed more moisture than untreated wood. This indicated that decay resistance of polysilicic acid-treated wood is caused by a different mechanism than desiccation. One possible mechanism may be attributed to direct disruption of permeability of fungal cell membranes by the low-molecular-weight polysilicic acid.

Keywords: Fungal decay protection, impregnation, moisture sorption, polysilicic acid, surfactant property

Category: Journal Articles
Unit: Performance Enhanced Bioploymers - FPL4707
File size: 610 kb(s)

Abstract: Interest in the use of nanoparticles of iron, titanium, aluminum, and zinc oxides in transparent coatings for wood is increasing. Such nano-composite coatings have the potential of not only preserving the natural color of the wood but also stabilizing the wood surface against the combined degradative effects of sunlight and moisture. The nanoparticles can be used as additives to coating formulations or deposited directly as thin films on a substrate. Thin film deposition can be accomplished by plasma-enhanced chemical vapor or by solgel deposition. This paper describes sol-gel deposition of a hybrid inorganic- organic thin film on wood using a mixture of metal-organic precursors and its effect on weathering properties of the wood surface.

Keywords: Sol-gel, wood, surface, thin film, moisture, weathering

Category: Research Notes
Unit: Pending
File size: 213 kb(s)

Abstract: This Research Note presents results of a preliminary study conducted to indicate the position of maximum stress along the axis of poles in three types of pole building frames in common use. Analysis was made by the matrix slope-deflection method using a high-speed digital computer, and was based on a loading condition considered critical for the three types of buildings, namely, wind from one side with the windward side of the building open. Connections were assumed to be either pinned or fixed, and for each condition under consideration, final moments, forces, and deformations were determined and compared.

Keywords: WIND STRESSES, bents, matrix-slope-deflection method

Category: Research Notes
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
File size: 89 kb(s)

Abstract: About 9 billion square feet of various types of wood-base fiber and particle panel materials are manufactured each year in the United States. Wood substance in one form or another is the principal raw material for all hardboard and particleboard. About two-thirds of the insulating board produced also is wood based; the remainder is made from bagasse (waste from sugar cane) and waste paper. Use of these products has increased about 50 percent during the past 7 years so their potential for utilization of residues is most important.

Keywords: Board materials, wood residues, Insulating board, granules, flakes, strands, curls, slivers, and fibers

Category: Research Notes
Unit: Pending
File size: 255 kb(s)

Abstract: Wood that is to be glued should have the proper amount of moisture uniformly distributed throughout, should be free from casehardening and other stresses, and should be surfaced smoothly, free from machine markings, and uniform in thickness.

Keywords: PROTEIN AND STARCH GLUES, casein, animal, open assembly, closed assembly

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

Abstract: The condition of wood surfaces at the time of gluing has an important influence on the strength of glue joints. Even with the best of woodworking glues and careful gluing technique, strong glue bonds will not result unless the wood surfaces have been well prepared and are free from contaminating substances and certain physical conditions that may interfere with adhesion of glues.

Keywords: gluing, plywood surfaces

Category: Research Notes
Unit: Pending
File size: 852 kb(s)

Abstract: Methods of obtaining strength and elastic properties of plastic laminates reinforced with unwoven glass fibers were evaluated using the criteria of the strength values obtained and the failure characteristics observed. Variables investigated were specimen configuration and the manner of supporting and loading the specimens. Results of this investigation indicate that satisfactory tensile failures can be obtained by reinforcing the shank portion of the tension specimen with 1/32-inch sheet aluminum. Variation of tensile specimen geometry was inconclusive, with at least partial failures always occurring in the shank portion. Difficulty was encountered in trying to obtain accurate compressive strength data on the composite material comprising these laminates. Some acceptable compression failures were obtained using a 5-1/8-inch-long specimen clamped at the ends and supported laterally by the standard FTM-406 jig, described in the Federal Test Method Standard No. 406. Failures varied for different laminates, indicating that resin properties may control failure when the material acts as a composite.

Keywords: strength and elastic properties, unwoven glass fibers, compressive strength

Category: Research Notes
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
File size: 1430 kb(s)

Abstract: The strength and behavior of three-member joints of 5/8 -inch Douglas-fir plywood nail-glued to 2 by 6 Douglas-fir lumber at different angles to the grain were evaluated after the joints were exposed to indoor, outdoor, and controlled tmospheric conditions for 13 months. Shear failure resulted in the plywood of all joints. The joints exposed to the different atmospheric conditions gave 3 to 15 percent lower ultimate shear strength than the joints loaded soon after assembly. Joints subjected to an imposed stress equivalent to about 25 percent of the ultimate joint stress were not weakened after 13 months.

Keywords: nail-glued joints, performance, Douglas-fir plywood, strength, durability

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

Abstract: Several hardwood neutral sulfite semichemical pulps were bleached to about 85 percent brightness with a two-stage application of sodium hypochlorite, using a total chlorine equivalent of 12 to 25 percent, depending on the yield of the unbleached pulp. Brightness gains decreased with increasing brightness of unbleached pulp. Yields of bleached pulps were from 3 to 5 percent higher with two-stage bleaching than they were with three-stage chlorination hypochlorite bleaching. With this process, however, 88 percent brightness was obtained with equal or lesser amounts of chlorine equivalent. Except for the highest yield pulp, hydrogen peroxide was as effective as hypo-chlorite in the second stage, but chlorine dioxide was about 10 percent less effective. Effect on strength varied from negligible to increases as much as 80 percent for the average overall strength.

Keywords: TWO-STAGE NONCHLORINATION BLEACHING,HARDWOOD NEUTRAL SULFITE SEMICHEMICAL PULPS

Category: Research Notes
Unit: Durability and Wood Protection Research - RWU4723
File size: 66 kb(s)

Abstract: The term cottonwood is applied to certain species of the genus, Populus, the most common of which are eastern cottonwood, P. deltoides, growing widely throughout the eastern United States, swamp cottonwood, P. heterophylla, an eastern lowland tree, and black cottonwood, P. trichocarpa, growing in the western United States. These species are known for their rapid growth and may attain a good size in 30 to 50 years. The wood of cottonwood is light in color and weight and uniform in texture. It is not strong nor durable under conditions favorable to decay. It is used extensively for lumber and veneer, particularly for shipping containers. For some years it has been used to a limited extent for the manufacture of plywood, some of which is used for purposes other than containers.

Keywords: veneer cutting, drying properties, cottonwood, mechanical veneer dryer,drying schedules

Category: Research Notes
Unit: Engineering Properties of Wood, Wood Based Materials, and Structures - RWU4714
File size: 153 kb(s)

Abstract: Efficient use of wood in storage buildings requires specialized knowledge of its directional strength properties, its response to long-time loading, its dimensional stability, insulating value, and resistance to fire and decay. Structural elements of wood or wood-base materials include sawn and round timbers, sheet materials, and a great variety of built-up or adhesive-bonded components. The high pressures on walls of storage structures and the moisture problems associated with the drying of stored materials require careful consideration in design.

Keywords: Bulk storage, dimensional stability, insulating value, resistance to fire and decay

Category: Research Notes
Unit: Pending
File size: 98 kb(s)

Abstract: Woodworking machines are made to do a wide variety of jobs. For any one job there are usually a number of makes, sizes, and styles of machines from which to choose. They are not standardized. Only a brief classification and outline of specifications for fairly typical machines of the more important types is attempted here. Small light machines of the home workshop size are not included. Woodworking machines may be divided into three broad classes based on function: sawmill, planing mill, and industrial plant machinery. The function of sawmill machinery is to cut the log into rough, green lumber. The planing mill takes the rough lumber (usually dry), and prepares it for general construction uses, such as flooring, siding, shiplap, or framing. The industrial plant cuts up lumber and makes it into doors, furniture, boxes, or other fabricated products.

Keywords: Woodworking machines, sawmill, planing mill, industrial plant machinery, Band Saws,Circular Saws,Portable circular mills,Stationary circular mills, Gang Saws

Category: Research Papers
Unit: Economics and Statistics Research - FPL4851
File size: 2580 kb(s)

Abstract: The North American wood pellet sector is profiled in this paper. A small pellet industry has existed since the 1930s, but its main growth occurred in the wake of the energy crisis in the 1970s. Its current spurt is even greater, growing from 1.1 million metric tonnes in 2003 to 4.2 million 2008. It is set to reach 6.2 million in 2009. Most plants are small, relying on sawmill residues for fiber and thus are limited to 100,000 tonnes or less per year. A number of new mills have been built to process chipped roundwood and have capacities three to four times as large. Most pellets made in the United States are consumed domestically, but a growing offshore market is boosting exports. By contrast, most Canadian pellets are shipped overseas. The reliance on sawmill residues led to imbalances between supply and demand for fiber as the sawmilling sector retrenched in the 2008-2009 recession. This has led mills to turn to roundwood or other non-sawmill sources of fiber. The wood pellet industry and use of wood pellets as energy are in their relative infancy in North America and the recent growth of both has been fueled by increases in the cost of fossil energy. However, policies aimed at reducing carbon dioxide emissions into the atmosphere could loom as bigger factors in the future.

Keywords: Wood pellets; demand and supply; production capacity

Category: Research Papers
Unit: Economics and Statistics Research - FPL4851
File size: 494 kb(s)

Abstract: In this paper, we take a preliminary look at techniques for comparing sorts that yield grades of lumber. We propose methodology that takes into account differences in grade prices and the costs associated with misgrading. We focus on two- and three-category sorts, but our results could be readily extended. We provide web links to sample FORTRAN implementations of this methodology for the case in which the strength predictor and strength have a bivariate normal distribution and the load distribution is also normally distributed. We indicate how these approaches would have to be modified for other predictor, strength, and load distributions.

Keywords: lumber grading; correlation estimation; comparing sorting procedures; classification

Category: Research In Progress
Unit: National Center for Wood Transportation Structures - NCWTS
File size: 1050 kb(s)

Abstract: Metallic fasteners have been used in covered bridges for centuries and have performed well in untreated timbers. However, durability concerns during rehabilitation of these historic structures typically dictate the use of treated wood. Because of environmental considerations, effective wood preservatives that have been used for many years are being replaced with newer wood preservatives, such as alkaline copper quaternary (ACQ) and copper azole (CuAz), that are showing accelerated corrosive effects on iron fasteners.

Keywords: corrosion; fasteners; treated wood; alkaline copper quaternary (ACQ); copper azole (CuAz); micronized copper quaternary (MCQ); covered bridge

Category: Research In Progress
Unit: National Center for Wood Transportation Structures - NCWTS
File size: 1310 kb(s)

Abstract: Wood that is exposed to moisture is vulnerable to attack by decay fungi and insects. Covered bridges were designed to prevent such biodeterioration by keeping the wood dry. However, protecting all bridge members from moisture is difficult, even in well-designed and well-maintained covered bridges. Members used in the abutments near the ends of bridges are especially vulnerable. Other areas may also be exposed when leaks go undetected or vandals remove cladding that protects the bridge interior. In all these situations, the integrity of critical bridge members can be extended by field application of preservative treatments. In this research project, we are developing a guide that will allow bridge maintenance personnel to select and effectively apply appropriate in-place treatments.

Keywords: in-place preservatives; covered bridge; moisture; field application; maintenance; decaycell; walls; Raman mapping; bioenergy

Category: Research In Progress
Unit: National Center for Wood Transportation Structures - NCWTS
File size: 926 kb(s)

Abstract: Covered bridges are historical masterpieces that were designed for protection from the elements, thereby allowing untreated wood components to remain serviceable for decades. However, protecting all wood components continuously from all sources of moisture exposure is impractical. Some areas of the structures, such as weatherboarding and wood members near the ends of the bridges, are particularly susceptible to wind-driven precipitation. Chronic exposure to moisture or wet and dry cycling from rain can increase the moisture content of wood components sufficiently to allow for biological attack by fungi and insects.

Keywords: Covered bridge; aboveground; natural durability; extractives; invasive species

Category: Research In Progress
Unit: National Center for Wood Transportation Structures - NCWTS
File size: 1060 kb(s)

Abstract: To extend the service life of historic covered bridges in the United States, methods for accurately estimating the strength and safety of the structure are required. Critical parts of this estimate are the species and grade of wood used in the construction of the bridge. With accurate information, an engineer or other professional can make determinations about maintenance, repair, restoration, or decommissioning of the structure.

Keywords: covered bridge; species identification; field grading; service life; structure strength

Category: Research In Progress
Unit: National Center for Wood Transportation Structures - NCWTS
File size: 1070 kb(s)

Abstract: Documentation of covered timber bridges is important to preserving their bridge life histories, as many are being lost forever. New laser scanning techniques will be used by a cooperative Forest Service and University of Minnesota Duluth research team to document several of these bridges in a rapid, accurate, and cost-effective manner. An implementation approach will be developed for using laser scanning for historic covered wood bridges.

Keywords: laser scanning; covered bridge; as built records; historic bridge; field tests; field measurements; HAER