Physical properties and consumer reaction to use of compressed wood bricks in southeast Alaska

Treesearch

Allen M. Brackley; Robert Gorman; Karen Peterson

2012-01-01

In late 2008, a group of business people and entrepreneurs in southeast Alaska became aware of a compressed wood brick product that could be used as an alternative fuel in existing wood-burning stoves and heating equipment. The product differed from many others on the market in that it contained no additive to promote binding and burn characteristics. In 2009, local...

Experimental Study of the Flexural and Compression Performance of an Innovative Pultruded Glass-Fiber-Reinforced Polymer-Wood Composite Profile.

PubMed

Qi, Yujun; Xiong, Wei; Liu, Weiqing; Fang, Hai; Lu, Weidong

2015-01-01

The plate of a pultruded fiber-reinforced polymer or fiber-reinforced plastic (FRP) profile produced via a pultrusion process is likely to undergo local buckling and cracking along the fiber direction under an external load. In this study, we constructed a pultruded glass-fiber-reinforced polymer-light wood composite (PGWC) profile to explore its mechanical performance. A rectangular cross-sectional PGWC profile was fabricated with a paulownia wood core, alkali-free glass fiber filaments, and unsaturated phthalate resin. Three-point bending and short column axial compression tests were conducted. Then, the stress calculation for the PGWC profile in the bending and axial compression tests was performed using the Timoshenko beam theory and the composite component analysis method to derive the flexural and axial compression rigidity of the profile during the elastic stress stage. The flexural capacity for this type of PGWC profile is 3.3-fold the sum of the flexural capacities of the wood core and the glass-fiber-reinforced polymer (GFRP) shell. The equivalent flexural rigidity is 1.5-fold the summed flexural rigidity of the wood core and GFRP shell. The maximum axial compressive bearing capacity for this type of PGWC profile can reach 1.79-fold the sum of those of the wood core and GFRP shell, and its elastic flexural rigidity is 1.2-fold the sum of their rigidities. These results indicate that in PGWC profiles, GFRP and wood materials have a positive combined effect. This study produced a pultruded composite material product with excellent mechanical performance for application in structures that require a large bearing capacity.

Experimental Study of the Flexural and Compression Performance of an Innovative Pultruded Glass-Fiber-Reinforced Polymer-Wood Composite Profile

PubMed Central

Qi, Yujun; Xiong, Wei; Liu, Weiqing; Fang, Hai; Lu, Weidong

2015-01-01

The plate of a pultruded fiber-reinforced polymer or fiber-reinforced plastic (FRP) profile produced via a pultrusion process is likely to undergo local buckling and cracking along the fiber direction under an external load. In this study, we constructed a pultruded glass-fiber-reinforced polymer-light wood composite (PGWC) profile to explore its mechanical performance. A rectangular cross-sectional PGWC profile was fabricated with a paulownia wood core, alkali-free glass fiber filaments, and unsaturated phthalate resin. Three-point bending and short column axial compression tests were conducted. Then, the stress calculation for the PGWC profile in the bending and axial compression tests was performed using the Timoshenko beam theory and the composite component analysis method to derive the flexural and axial compression rigidity of the profile during the elastic stress stage. The flexural capacity for this type of PGWC profile is 3.3-fold the sum of the flexural capacities of the wood core and the glass-fiber-reinforced polymer (GFRP) shell. The equivalent flexural rigidity is 1.5-fold the summed flexural rigidity of the wood core and GFRP shell. The maximum axial compressive bearing capacity for this type of PGWC profile can reach 1.79-fold the sum of those of the wood core and GFRP shell, and its elastic flexural rigidity is 1.2-fold the sum of their rigidities. These results indicate that in PGWC profiles, GFRP and wood materials have a positive combined effect. This study produced a pultruded composite material product with excellent mechanical performance for application in structures that require a large bearing capacity. PMID:26485431

Endogenous indole-3-acetic acid and ethylene evolution in tilted Metasequoia glyptostroboides stems in relation to compression-wood formation.

PubMed

Du, Sheng; Sugano, Mami; Tsushima, Miho; Nakamura, Teruko; Yamamoto, Fukuju

2004-04-01

Eight-year-old Metasequoia glyptostroboides seedlings were tilted at a 45 degrees angle to induce compression-wood formation on the lower side of the stems. After 2 weeks of treatment, half of the seedlings were sampled and the remaining half were tilted to the opposite orientation to exchange the upper and lower sides and were kept for 2 more weeks until sampled. Cambium-emitted ethylene was analyzed by gas chromatography with flame-ionization detection. Endogenous indole-3-acetic acid (IAA) was measured by gas chromatography-mass spectrometry. Tracheid production and compression-wood formation were determined by light microscopy. Anatomical studies showed that tracheid production was promoted and compression-wood tracheids always developed on the gravitationally lower side of tilted stems in both the original tilting and the subsequent reverse-tilting periods. These were accompanied by an increase in IAA content in and an accelerated ethylene-evolution rate from the cambial region of the same side.

Tension and Compression Creep Apparatus for wood-Plastic Composites

Treesearch

Scott E. Hamel; John C. Hermanson; Steven M. Cramer

2011-01-01

Design of structural members made of wood-plastic composites (WPC) is not possible without accurate test data for tension and compression. The viscoelastic behavior of these materials means that these data are required for both the quasi-static stress-strain response, and the long-term creep response. Their relative incompressibility causes inherent difficulties in...

Hydraulic efficiency compromises compression strength perpendicular to the grain in Norway spruce trunkwood

PubMed Central

2011-01-01

The aim of this study was to investigate bending stiffness and compression strength perpendicular to the grain of Norway spruce (Picea abies (L.) Karst.) trunkwood with different anatomical and hydraulic properties. Hydraulically less safe mature sapwood had bigger hydraulic lumen diameters and higher specific hydraulic conductivities than hydraulically safer juvenile wood. Bending stiffness (MOE) was higher, whereas radial compression strength lower in mature than in juvenile wood. A density-based tradeoff between MOE and hydraulic efficiency was apparent in mature wood only. Across cambial age, bending stiffness did not compromise hydraulic efficiency due to variation in latewood percent and because of the structural demands of the tree top (e.g. high flexibility). Radial compression strength compromised, however, hydraulic efficiency because it was extremely dependent on the characteristics of the “weakest” wood part, the highly conductive earlywood. An increase in conduit wall reinforcement of earlywood tracheids would be too costly for the tree. Increasing radial compression strength by modification of microfibril angles or ray cell number could result in a decrease of MOE, which would negatively affect the trunk’s capability to support the crown. We propose that radial compression strength could be an easily assessable and highly predictive parameter for the resistance against implosion or vulnerability to cavitation across conifer species, which should be topic of further studies. PMID:22058609

Effects of swelling forces on the durability of wood adhesive bonds

Treesearch

Blake M. Hofferber; Edward Kolodka; Rishawn Brandon; Robert J. Moon; Charles R. Frihart

2006-01-01

The purpose of this study was to investigate the role of wood swelling on performance of wood-adhesive bonds (resorcinol formaldehyde, epoxy, emulsion polymerisocyanate), for untreated and acetylated wood. Effects of these treatments on measured strain anisotropy and swelling stress were measured and then related to compressive shear strength and percentage wood...

Localization of Cell Wall Polysaccharides in Normal and Compression Wood of Radiata Pine: Relationships with Lignification and Microfibril Orientation1

PubMed Central

Donaldson, Lloyd A.; Knox, J. Paul

2012-01-01

The distribution of noncellulosic polysaccharides in cell walls of tracheids and xylem parenchyma cells in normal and compression wood of Pinus radiata, was examined to determine the relationships with lignification and cellulose microfibril orientation. Using fluorescence microscopy combined with immunocytochemistry, monoclonal antibodies were used to detect xyloglucan (LM15), β(1,4)-galactan (LM5), heteroxylan (LM10 and LM11), and galactoglucomannan (LM21 and LM22). Lignin and crystalline cellulose were localized on the same sections used for immunocytochemistry by autofluorescence and polarized light microscopy, respectively. Changes in the distribution of noncellulosic polysaccharides between normal and compression wood were associated with changes in lignin distribution. Increased lignification of compression wood secondary walls was associated with novel deposition of β(1,4)-galactan and with reduced amounts of xylan and mannan in the outer S2 (S2L) region of tracheids. Xylan and mannan were detected in all lignified xylem cell types (tracheids, ray tracheids, and thick-walled ray parenchyma) but were not detected in unlignified cell types (thin-walled ray parenchyma and resin canal parenchyma). Mannan was absent from the highly lignified compound middle lamella, but xylan occurred throughout the cell walls of tracheids. Using colocalization measurements, we confirmed that polysaccharides containing galactose, mannose, and xylose have consistent correlations with lignification. Low or unsubstituted xylans were localized in cell wall layers characterized by transverse cellulose microfibril orientation in both normal and compression wood tracheids. Our results support the theory that the assembly of wood cell walls, including lignification and microfibril orientation, may be mediated by changes in the amount and distribution of noncellulosic polysaccharides. PMID:22147521

Fixation of compressive deformation in wood by pre-steaming

Treesearch

M. Inoue; N. Sekino; T. Morooka; R.M. Rowell; M. Norimoto

2008-01-01

Wood block specimens pre-steamed at 120-220 °C for 5-20 min were compressed in the radial direction. The recovery of set decreased with increasing pre-steaming temperature and time. The reduction of set recovery correlated with the amount of weight loss in steaming irrespective of pre-steaming temperature and time. The weight loss for the highest level of...

Physical and mechanical properties of bio-composites from wood particles and liquefied wood resin

Treesearch

Hui Pan; Todd F. Shupe; Chung-Yun Hse

2009-01-01

Compression molded composites were made from wood particles and a liquefied wood/phenol/formaldehyde co-condensed resin. Based on our previous research, a phenol to wood (P/W) ratio of 2/1 was chosen for this study. The two experimental variables selected were: 1) liquefaction temperature (150o and 180oC) and 2) cooking method (atmospheric and sealed). Panels were...

Improving the mechanical performance of wood fiber reinforced bio-based polyurethane foam

NASA Astrophysics Data System (ADS)

Chang, Li-Chi

Because of the environmental impact of fossil fuel consumption, soybean-based polyurethane (PU) foam has been developed as an alternative to be used as the core in structural insulated panels (SIPs). Wood fibers can be added to enhance the resistance of foam against bending and buckling in compression. The goal of this work is to study the effect of three modifications: fiber surface treatment, catalyst choice, and mixing method on the compression performance of wood fiber-reinforced PU foam. Foams were made with a free-rising process. The compression performance of the foams was measured and the foams were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray computed tomography (CT). The foam reinforced with alkali-treated fibers had improved compression performance. The foams made with various catalysts shared similar performance. The foam made using a mechanical stirrer contained well-dispersed fibers but the reinforcing capability of the fibers was reduced.

The Mechanical Properties of Wood of Different Moisture Content Within -200 Degrees to +200 Degrees C Temperature Range

NASA Technical Reports Server (NTRS)

Kollmann, Franz

1941-01-01

Systematic experiments were undertaken with special reference to the effect of gross specific weight (specific weight inclusive of pores) and the moisture content of wood. It was found that the modules of elasticity of wood at room temperature and frozen at -8 degrees is practically the same. The effect of moisture on the compression strength of frozen wood was explored as well as the flexural and impact strength of frozen wood and frozen laminated wood.

Plant Growth Facility (PGF)

NASA Technical Reports Server (NTRS)

1998-01-01

In a microgravity environment aboard the Space Shuttle Columbia Life and Microgravity Mission STS-78, compression wood formation and hence altered lignin deposition and cell wall structure, was induced upon mechanically bending the stems of the woody gymnosperms, Douglas fir (Pseudotsuga menziesii) and loblolly pine (Pinus taeda). Although there was significant degradation of many of the plant specimens in space-flight due to unusually high temperatures experienced during the mission, it seems evident that gravity had little or no effect on compression wood formation upon bending even in microgravity. Instead, it apparently results from alterations in the stress gradient experienced by the plant itself during bending under these conditions. This preliminary study now sets the stage for long-term plant growth experiments to determine whether compression wood formation can be induced in microgravity during phototropic-guided realignment of growing woody plant specimens, in the absence of any externally provided stress and strain.

Testing compression strength of wood logs by drilling resistance

NASA Astrophysics Data System (ADS)

Kalny, Gerda; Rados, Kristijan; Rauch, Hans Peter

2017-04-01

Soil bioengineering is a construction technique using biological components for hydraulic and civil engineering solutions, based on the application of living plants and other auxiliary materials including among others log wood. Considering the reliability of the construction it is important to know about the durability and the degradation process of the wooden logs to estimate and retain the integral performance of a soil bioengineering system. An important performance indicator is the compression strength, but this parameter is not easy to examine by non-destructive methods. The Rinntech Resistograph is an instrument to measure the drilling resistance by a 3 mm wide needle in a wooden log. It is a quasi-non-destructive method as the remaining hole has no weakening effects to the wood. This is an easy procedure but result in values, hard to interpret. To assign drilling resistance values to specific compression strengths, wooden specimens were tested in an experiment and analysed with the Resistograph. Afterwards compression tests were done at the same specimens. This should allow an easier interpretation of drilling resistance curves in future. For detailed analyses specimens were investigated by means of branch inclusions, cracks and distances between annual rings. Wood specimens are tested perpendicular to the grain. First results show a correlation between drilling resistance and compression strength by using the mean drilling resistance, average width of the annual rings and the mean range of the minima and maxima values as factors for the drilling resistance. The extended limit of proportionality, the offset yield strength and the maximum strength were taken as parameters for compression strength. Further investigations at a second point in time strengthen these results.

Justification of the Production Process of Pressed Wood and Study of its Properties

NASA Astrophysics Data System (ADS)

Polilov, A. N.; Dornyak, O. R.; Shamaev, V. A.; Rumachik, M. M.

2018-05-01

Results of a numerical analysis of the stress-strain state of wood during its pressing in different symmetry directions of the anisotropic material are presented. It is shown that the anisotropy of mechanical properties of wood is an important factor determining both the structural characteristics of the porous system and its strength. A mathematical modeling of the process of pressing wood as a three-phase anisotropic rheologically complex capillary-porous system allows one to predict parameters of the resulting wood composite. The compressed wood obtained by the production modes developed has a tensile strength eight times greater than that of the natural one, which is comparable to the strength of the St3 steel, but its specific strength is higher than that of the St45 steel. Compression and impregnation of softwood species with an aqueous solution of carbamide allows one to harden them. This kind of treatment endows the wood with enhanced strength characteristics comparable to the characteristics of the St3 steel. The special features of tensile tests used to estimate the elastic modulus and strength characteristics of such materials are considered. Data obtained by different testing methods are correlated, and characteristics of the strengthened wood and some brends of steel are compared.

Compression Debarking of Stored Wood Chips

Treesearch

James A. Mattson

1974-01-01

Two 750 ft. piles of unbarked chips were stored for 1 year to evaluate the effect of chip storage on the effectiveness of bark-chip separations-segregation methods under study. in processing stored chips suffered more wood loss than fresh chips.

Water removal of wet veneer by roller pressing

Treesearch

Koji Adachi; Masafumi Inoue; Kozo Kanayama; Roger M. Rowell; Shuichi Kawai

2004-01-01

High moisture content, flat sawn Japanese cedar (Cryptomeria japonica D. Don) veneer was compressed using a roller press to mechanically remove water. The amount of water removed depended on the amount of compression applied. At 60% compression, 400 kg/m3 of water was removed. The process was not dependent on the size of the wood, the degree of compression, or the feed...

Induced compression wood formation in Douglas fir (Pseudotsuga menziesii) in microgravity

NASA Technical Reports Server (NTRS)

Kwon, M.; Bedgar, D. L.; Piastuch, W.; Davin, L. B.; Lewis, N. G.

2001-01-01

In the microgravity environment of the Space Shuttle Columbia (Life and Microgravity Mission STS-78), were grown 1-year-old Douglas fir and loblolly pine plants in a NASA plant growth facility. Several plants were harnessed (at 45 degrees ) to establish if compression wood biosynthesis, involving altered cellulose and lignin deposition and cell wall structure would occur under those conditions of induced mechanical stress. Selected plants were harnessed at day 2 in orbit, with stem sections of specific plants harvested and fixed for subsequent microscopic analyses on days 8, 10 and 15. At the end of the total space mission period (17 days), the remaining healthy harnessed plants and their vertical (upright) controls were harvested and fixed on earth. All harnessed (at 45 degrees ) plant specimens, whether grown at 1 g or in microgravity, formed compression wood. Moreover, not only the cambial cells but also the developing tracheid cells underwent significant morphological changes. This indicated that the developing tracheids from the primary cell wall expansion stage to the fully lignified maturation stage are involved in the perception and transduction of the stimuli stipulating the need for alteration of cell wall architecture. It is thus apparent that, even in a microgravity environment, woody plants can make appropriate corrections to compensate for stress gradients introduced by mechanical bending, thereby enabling compression wood to be formed. The evolutionary implications of these findings are discussed in terms of "variability" in cell wall biosynthesis.

Effects of processing method and moisture history on laboratory fungal resistance of wood-HDPE composites.

Treesearch

Craig M. Clemons; Rebecca E. Ibach

2004-01-01

The purpose of this study was to clarify the effects of composite processing and moisture sorption on laboratory fungal resistance of wood-plastic composites. A 2-week water soaking or cyclic boiling-drying procedure was used to infuse moisture into composites made from high-density polyethylene filled with 50 percent wood flour and processed by extrusion, compression...

A reassessment of the compressive strength properties of southern yellow pine bark

Treesearch

Thomas L. Eberhardt

2007-01-01

Samples of southern yellow pine outer bark and wood were tested in compression to determine values for modulus of elasticity, stress at proportional limit, and maximum crushing strength. Results reported here resolve inconsistencies in the compressive strength data previously reported by others for pine bark. Testing of solvent-treated bark blocks suggests that...

Current work in ontario on compression wood in black spruce in relation to pulp yield and quality

Treesearch

J.L. Ladell; A.J. Carmichael; G.H.S. Thomas

1968-01-01

In 1959 and 1960, during a series of symposia on wood quality organized jointly by the Ontario Department of Lands and Forests, the Faculty of Forestry of the University of Toronto, and the Ontario Research Foundation (ORF), it became clear that there was a serious lack of information regarding the structure and variability of the wood of the commercially important...

Comparisons of Wet and Ovendry Analyses of Compression Debarking Tests on Wood Chips

Treesearch

Rodger A. Arola

1974-01-01

Compares the level of bark removal from chips and resultant wood losses when measured on both a wet and ovendry basis with several chip debarking trials for quaking aspen, jack pine, and sugar maple cut at different times of the year.

Physical Properties of Synthetic Resin Materials

NASA Technical Reports Server (NTRS)

Fishbein, Meyer

1939-01-01

A study was made to determine the physical properties of synthetic resins having paper, canvas, and linen reinforcements, and of laminated wood impregnated with a resin varnish. The results show that commercial resins have moduli of elasticity that are too low for structural considerations. Nevertheless, there do exist plastics that have favorable mechanical properties and, with further development, it should be possible to produce resin products that compare favorably with the light-metal alloys. The results obtained from tests on Compound 1840, resin-impregnated wood, show that this material can stand on its own merit by virtue of a compressive strength four times that of the natural wood. This increase in compressive strength was accomplished with an increase of density to a value slightly below three times the normal value and corrected one of the most serious defects of the natural product.

Axial compression behaviour of reinforced wallettes fabricated using wood-wool cement panel

NASA Astrophysics Data System (ADS)

Noh, M. S. Md; Kamarudin, A. F.; Mokhatar, S. N.; Jaudin, A. R.; Ahmad, Z.; Ibrahim, A.; Muhamad, A. A.

2018-04-01

Wood-wool cement composite panel (WWCP) is one of wood based composite material that produced in a stable panel form and suitable to be used as building wall system to replace non-ecofriendly material such as brick and other masonry element. Heavy construction material such as brick requires more manpower and consume a lot of time to build the wall panel. WWCP is a lightweight material with a density range from 300 kg/m3 to 500 kg/m3 and also capable to support an imposed load from the building. This study reported on the axial compression behaviour of prefabricated reinforced wallettes constructed with wood-wool cement panel. A total of six specimens were fabricated using two layers of cross laminated WWCP bonded with normal mortar paste (Portland cement) at a mix ratio of 1:3 (cement : sand). As part of lifting mechanism, the wallettes were equipped with three steel reinforcement (T12) that embedded inside the core of wallettes. Three replicates of wallettes specimens with dimension 600 mm width and 600 mm length were fabricated without surface plaster and with 16 mm thickness of surface plaster. The wallettes were tested under axial compression load after 28 days of fabrication until failure. The result indicated that, the application of surface plaster significantly increases the loading capacity about 35 % and different orientation of the panels improve the bonding strength of the wall.

The influence of juvenile wood content on shear parallel, compression,and tension perpendicular to grain strength and mode I fracture toughness of loblolly pine at various ring orientation

Treesearch

David E. Kretschmann

2008-01-01

Forest products from improved trees grown on managed plantations and harvested in short rotations will contain higher proportions of juvenile wood than in current harvests. More information is needed on the influence of juvenile wood on lumber properties. Most information developed to date has concentrated on ultimate tensile stress, modulus of rupture, and modulus of...

Deformation and failure mechanism of secondary cell wall in Spruce late wood

NASA Astrophysics Data System (ADS)

Adusumalli, Ramesh-Babu; Raghavan, Rejin; Ghisleni, Rudy; Zimmermann, Tanja; Michler, Johann

2010-08-01

The deformation and failure of the secondary cell wall of Spruce wood was studied by in-situ SEM compression of micropillars machined by the focused ion beam technique. The cell wall exhibited yield strength values of approximately 160 MPa and large scale plasticity. High resolution SEM imaging post compression revealed bulging of the pillars followed by shear failure. With additional aid of cross-sectional analysis of the micropillars post compression, a model for deformation and failure mechanism of the cell wall has been proposed. The cell wall consists of oriented cellulose microfibrils with high aspect ratio embedded in a hemicellulose-lignin matrix. The deformation of the secondary wall occurs by asymmetric out of plane bulging because of buckling of the microfibrils. Failure of the cell wall following the deformation occurs by the formation of a shear or kink band.

Chip Debarking of Several Western Species

Treesearch

William A. Hillstrom

1974-01-01

Discusses processing and conditioning treatments before and aftger compression debarking of western hemlock, Douglas fir, red alder, and bigleaf maple. Bark removal and wood recovery from red alder far exceeded the other species tested. Approximately 90 percent of the wood fiber input was recovered at a residual bark content of less than 2 percent by weight.

Predicting the flexure response of wood-plastic composites from uni-axial and shear data using a finite-element model

Treesearch

Scott E. Hamel; John C. Hermanson; Steven M. Cramer

2014-01-01

Wood-plastic composites (WPCs), commonly used in residential decks and railings, exhibit mechanical behavior that is bimodal, anisotropic, and nonlinear viscoelastic. They exhibit different stress-strain responses to tension and compression, both of which are nonlinear. Their mechanical properties vary with respect to extrusion direction, their deformation under...

Guying to prevent wind sway influences loblolly pine growth and wood properties

Treesearch

James D. Burton; Diana M. Smith

1972-01-01

Restraining young loblolly pine (Pinus taeda L.) trees from normal swaying in the wind markedly reduced radial growth in the immobilized portion of the bole and accelerated it in the upper, free-swaying portion. Guying also reduced specific gravity, number of earlywood and latewood tracheids, latewood tracheid diameter, and amount of compression wood...

Stem Sinuosity of Loblolly Pine Seedlings as Influenced by Taproot Shape

Treesearch

Michael S. Murphy; Timothy B. Harrington

2004-01-01

Sinuous stem growth in loblolly pine (Pinus taeda L.) results in diminished potential for the utilization of wood products since these stems are difficult to mill and contain a higher percentage of compression wood. In this study, 90 full-sibling loblolly pine seedlings (30 seedlings from each of 3 families) were planted with 5 taproot configurations...

Transverse stresses and modes of failure in tree branches and other beams.

PubMed

Ennos, A R; van Casteren, A

2010-04-22

The longitudinal stresses in beams subjected to bending also set up transverse stresses within them; they compress the cross section when the beam's curvature is being increased and stretch it when its curvature is being reduced. Analysis shows that transverse stresses rise to a maximum at the neutral axis and increase with both the bending moment applied and the curvature of the beam. These stresses can qualitatively explain the fracture behaviour of tree branches. Curved 'hazard beams' that are being straightened split down the middle because of the low transverse tensile strength of wood. By contrast, straight branches of light wood buckle when they are bent because of its low transverse compressive strength. Branches of denser wood break, but the low transverse tensile strength diverts the crack longitudinally when the fracture has only run half-way across the beam, to produce their characteristic 'greenstick fracture'. The bones of young mammals and uniaxially reinforced composite beams may also be prone to greenstick fracture because of their lower transverse tensile strength.

Dimensional Changes of Tracheids during Drying of Radiata Pine (Pinus radiata D. Don) Compression Woods: A Study Using Variable-Pressure Scanning Electron Microscopy (VP-SEM)

PubMed Central

Zhang, Miao; Smith, Bronwen G.; McArdle, Brian H.; Chavan, Ramesh R.; James, Bryony J.

2018-01-01

Variable-pressure scanning electron microscopy was used to investigate the dimensional changes in longitudinal, tangential and radial directions, on wetting and drying, of tracheids of opposite wood (OW) and three grades of compression woods (CWs), including severe CW (SCW) and two grades of mild compression wood (MCW) (MCW1 and MCW2) in corewood of radiata pine (Pinus radiata) saplings. The CW was formed on the underside and OW on the upper side of slightly tilted stems. In the longitudinal direction, the shrinkage of SCW tracheids was ~300% greater than that of OW tracheids, with the shrinkage of the MCW1 and MCW2 tracheids being intermediate. Longitudinal swelling was also investigated and hysteresis was demonstrated for the tracheids of all corewood types, with the extent of hysteresis increasing with CW severity. A statistical association was found between longitudinal shrinkage and the content of lignin and galactosyl residues in the cell-wall matrix. The galactosyl residues are present mostly as (1→4)-β-galactans, which are known to have a high capacity for binding water and swell on hydration. The small proportions of (1→3)-β-glucans in the CWs have similar properties. These polysaccharides may play a functional role in the longitudinal shrinking and swelling of CW tracheids. Tangential shrinkage of tracheids was greater than radial shrinkage but both were greatest for OW and least for SCW, with the MCW1 and MCW2 being intermediate. PMID:29495536

Mechanical and time-dependent behavior of wood-plastic composites subjected to tension and compression

Treesearch

Scott E. Hamel; John C. Hermanson; Steven M. Cramer

2012-01-01

The thermoplastics within wood—plastic composites (WPCs) are known to experience significant time-dependent deformation or creep. In some formulations, creep deformation can be twice as much as the initial quasi-static strain in as little as 4 days. While extensive work has been done on the creep behavior of pure polymers, little information is available on the...

Golgi Enrichment and Proteomic Analysis of Developing Pinus radiata Xylem by Free-Flow Electrophoresis

PubMed Central

Macdonald, Lucy J.; Adams, Paul D.; Petzold, Christopher J.; Strabala, Timothy J.; Wagner, Armin; Heazlewood, Joshua L.

2013-01-01

Our understanding of the contribution of Golgi proteins to cell wall and wood formation in any woody plant species is limited. Currently, little Golgi proteomics data exists for wood-forming tissues. In this study, we attempted to address this issue by generating and analyzing Golgi-enriched membrane preparations from developing xylem of compression wood from the conifer Pinus radiata. Developing xylem samples from 3-year-old pine trees were harvested for this purpose at a time of active growth and subjected to a combination of density centrifugation followed by free flow electrophoresis, a surface charge separation technique used in the enrichment of Golgi membranes. This combination of techniques was successful in achieving an approximately 200-fold increase in the activity of the Golgi marker galactan synthase and represents a significant improvement for proteomic analyses of the Golgi from conifers. A total of thirty known Golgi proteins were identified by mass spectrometry including glycosyltransferases from gene families involved in glucomannan and glucuronoxylan biosynthesis. The free flow electrophoresis fractions of enriched Golgi were highly abundant in structural proteins (actin and tubulin) indicating a role for the cytoskeleton during compression wood formation. The mass spectrometry proteomics data associated with this study have been deposited to the ProteomeXchange with identifier PXD000557. PMID:24416096

The structure and mechanics of Moso bamboo material

PubMed Central

Dixon, P. G.; Gibson, L. J.

2014-01-01

Although bamboo has been used structurally for millennia, there is currently increasing interest in the development of renewable and sustainable structural bamboo products (SBPs). These SBPs are analogous to wood products such as plywood, oriented strand board and glue-laminated wood. In this study, the properties of natural Moso bamboo (Phyllostachys pubescens) are investigated to further enable the processing and design of SBPs. The radial and longitudinal density gradients in bamboo give rise to variations in the mechanical properties. Here, we measure the flexural properties of Moso bamboo in the axial direction, along with the compressive strengths in the axial and transverse directions. Based on the microstructural variations (observed with scanning electron microscopy) and extrapolated solid cell wall properties of bamboo, we develop models, which describe the experimental results well. Compared to common North American construction woods loaded along the axial direction, Moso bamboo is approximately as stiff and substantially stronger, in both flexure and compression but denser. This work contributes to critical knowledge surrounding the microstructure and mechanical properties of bamboo, which are vital to the engineering and design of sustainable SBPs. PMID:25056211

Transverse stresses and modes of failure in tree branches and other beams

PubMed Central

Ennos, A. R.; van Casteren, A.

2010-01-01

The longitudinal stresses in beams subjected to bending also set up transverse stresses within them; they compress the cross section when the beam's curvature is being increased and stretch it when its curvature is being reduced. Analysis shows that transverse stresses rise to a maximum at the neutral axis and increase with both the bending moment applied and the curvature of the beam. These stresses can qualitatively explain the fracture behaviour of tree branches. Curved ‘hazard beams’ that are being straightened split down the middle because of the low transverse tensile strength of wood. By contrast, straight branches of light wood buckle when they are bent because of its low transverse compressive strength. Branches of denser wood break, but the low transverse tensile strength diverts the crack longitudinally when the fracture has only run half-way across the beam, to produce their characteristic ‘greenstick fracture’. The bones of young mammals and uniaxially reinforced composite beams may also be prone to greenstick fracture because of their lower transverse tensile strength. PMID:20018786

Hydraulic and mechanical properties of young Norway spruce clones related to growth and wood structure

PubMed Central

ROSNER, SABINE; KLEIN, ANDREA; MÜLLER, ULRICH; KARLSSON, BO

2011-01-01

Summary Stem segments of eight five-year-old Norway spruce (Picea abies (L.) Karst.) clones differing in growth characteristics were tested for maximum specific hydraulic conductivity (ks100), vulnerability to cavitation and behavior under mechanical stress. The vulnerability of the clones to cavitation was assessed by measuring the applied air pressure required to cause 12 and 50% loss of conductivity (Ψ12, Ψ50) and the percent loss of conductivity at 4 MPa applied air pressure (PLC4MPa). The bending strength and stiffness and the axial compression strength and stiffness of the same stem segments were measured to characterize wood mechanical properties. Growth ring width, wood density, latewood percentage, lumen diameter, cell wall thickness, tracheid length and pit dimensions of earlywood cells, spiral grain and microfibril angles were examined to identify structure–function relationships. High ks100 was strongly and positively related to spiral grain angle, which corresponded positively to tracheid length and pit dimensions. Spiral grain may reduce flow resistance of the bordered pits of the first earlywood tracheids, which are characterized by rounded tips and an equal distribution of pits along the entire length. Wood density was unrelated to hydraulic vulnerability parameters. Traits associated with higher hydraulic vulnerability were long tracheids, high latewood percentage and thick earlywood cell walls. The positive relationship between earlywood cell wall thickness and vulnerability to cavitation suggest that air seeding through the margo of bordered pits may occur in earlywood. There was a positive phenotypic and genotypic relationship between ks100 and PLC4MPa, and both parameters were positively related to tree growth rate. Variability in mechanical properties depended mostly on wood density, but also on the amount of compression wood. Accordingly, hydraulic conductivity and mechanical strength or stiffness showed no tradeoff. PMID:17472942

Influence of juvenile wood content on shear parallel, compression, and tension transverse to grain strength and mode I fracture toughness for loblolly pine

Treesearch

David E. Kretschmann

2008-01-01

To satisfy the increased demand for forest products, much of future timber supply is expected to be from improved trees grown on managed plantations. This fast growth resource will tend to be harvested in short-age rotations and will contain higher proportions of juvenile wood than those of current harvests. In anticipation of this resource, definitive information is...

Evaluation of Efficient XML Interchange (EXI) for Large Datasets and as an Alternative to Binary JSON Encodings

DTIC Science & Technology

2015-03-01

fall in the lossy category (Gonzalez, Woods , & Eddins, 2009, p. 420). For the textual or numeric data in XML, however, lossy compression is...7/1,337 > Professional Notes Being Efficient with Bandwidth By Lieutenant Commander Steve Debich, Lieutenant Bruce Hill, Captain Scot Miller (Retired...2005). XML Binary Characterization. Retrieved from http://www.w3.org/TR/xbc-characterization/ Gonzalez, R., Woods , R., & Eddins, S. (2009

Reactive Processing of Environment Conscious, Biomorphic Ceramics: A Novel and Eco-friendly Route to Advanced Ceramic

NASA Technical Reports Server (NTRS)

Singh, M.

2002-01-01

Environment-conscious, biomorphic ceramics (Ecoceramics) are a new class of materials that can be produced with renewable resources (wood) and wood wastes (wood sawdust). These materials have tailorable properties with numerous potential applications. Silicon carbide-based ecoceramics have been fabricated by the infiltration of wood-derived carbonaceous preforms with oxide and silicon based materials. The wood-derived carbonaceous preforms have been shown to be quite useful in producing porous or dense materials with different microstructures and compositions. The microstructure and mechanical properties (flexural strength, fracture toughness, elastic modulus, and compressive strength) of a wide variety of Sic-based ecoceramics have been measured. Ecoceramics have tailorable properties and behave like ceramic materials manufactured by conventional approaches. In this presentation the fabrication approach, microstructure, and thermomechanical properties of a wide variety of Sic-based Ecoceramics will be reported.

Critical review on the mechanisms of maturation stress generation in trees

PubMed Central

Clair, Bruno

2016-01-01

Trees control their posture by generating asymmetric mechanical stress around the periphery of the trunk or branches. This stress is produced in wood during the maturation of the cell wall. When the need for reaction is high, it is accompanied by strong changes in cell organization and composition called reaction wood, namely compression wood in gymnosperms and tension wood in angiosperms. The process by which stress is generated in the cell wall during its formation is not yet known, and various hypothetical mechanisms have been proposed in the literature. Here we aim at discriminating between these models. First, we summarize current knowledge about reaction wood structure, state and behaviour relevant to the understanding of maturation stress generation. Then, the mechanisms proposed in the literature are listed and discussed in order to identify which can be rejected based on their inconsistency with current knowledge at the frontier between plant science and mechanical engineering. PMID:27605169

Nde of Lumber and Natural Fiber Based Products with Air Coupled Ultrasound

NASA Astrophysics Data System (ADS)

Hsu, David K.; Utrata, David; Kuo, Monlin

2010-02-01

Due to the porous nature of wood and natural fiber based products, conventional fluid or gel coupled ultrasonic inspection is unsuitable. Air-coupled ultrasonic transmission scanning, being non-contact, is ideally suited for inspecting lumber, wood and natural fiber based products. We report here several successful applications of air-coupled ultrasound for the inspection of wood. Air-coupled ultrasonic scan at 120 kHz can easily detect "sinker-stock" lumber in which bacterial damage of ray tissue cells had occurred during anaerobic pond storage. Channels in ash lumber board caused by insect bore were imaged in transmission scan. Delamination and material inhomogeneities were mapped out in manufactured wood and natural fiber products including medium density fiberboards, compression molded shredded waste wood with formaldehyde resin, and acoustic panels molded with kenaf fibers. The study has demonstrated some of the capabilities of air-coupled ultrasound in the NDE of forest products.

Wood-Based Nanocomposite Derived by in Situ Formation of Organic-Inorganic Hybrid Polymer within Wood via a Sol-Gel Method.

PubMed

Dong, Xiaoying; Zhuo, Xiao; Wei, Jie; Zhang, Gang; Li, Yongfeng

2017-03-15

Solid wood materials and wood-plastic composites as two kinds of lightweight materials are attracting great interest from academia and industry due to their green and recycling nature. However, the relatively lower specific strength limits their wider applications. In particular, solid wood is vulnerable to moisture and decay fungi in nature, resulting in its poor durability for effectively long-term utilization. Inspired from the porous structure of wood, we propose a new design to build a wood-based nanocomposite with higher specific strength and satisfactory durability by in situ generation of organic-inorganic hybrid polymer within wood via a sol-gel method. The derived composite has 50-1200% improvement of impact toughness, 56-192% improvement of tensile strength, and 110-291% improvement of flexural strength over those of typical wood-plastic composites, respectively; and even 34% improvement of specific tensile strength than that of 36A steel; 208% enhancement of hardness; and 156% enhancement of compression strength than those of compared solid wood, respectively; as well as significantly improved dimensional stability and decay resistance over those of untreated natural wood. Such materials could be potentially utilized as lightweight and high-strength materials for applications in construction and automotive industries. This method could be extended to constitute other inorganic nanomaterials for novel organic-inorganic hybrid polymer within wood.

Properties of wood-plastic composites: effect of inorganic additives

NASA Astrophysics Data System (ADS)

Bakraji, Elias Hanna; Salman, Numan

2003-01-01

Wood-plastic composites from Syrian tree species (white poplar, cypress tree, and white willow) were prepared using gamma-ray irradiation. Dry wood was impregnated with acrylamide or butylmethacrylate at various methanol compositions as the swelling solvent. Effect of inorganic additives and co-additives such as lithium nitrate (LiNO 3), copper sulfate (CuSO 4) and sulfuric acid (H 2SO 4), used at a very low concentration (1%), on the polymer loading (PL) and the compression strength (CS) was also investigated. It has been found that all the additives and co-additives, except Cu 2+, increase the PL values and only Li + has a positive effect on CS.

The effects of heat treatment on some technological properties of Scots pine (Pinus sylvestris L.) wood.

PubMed

Korkut, Süleyman; Akgül, Mehmet; Dündar, Turker

2008-04-01

Heat treatment is often applied to wood species to improve their dimensional stability. This study examined the effect of heat treatment on certain mechanical properties of Scots pine (Pinus sylvestris L.), which has industrially high usage potential and large plantations in Turkey. Wood specimens obtained from Bolu, Turkey, were subjected to heat treatment under atmospheric pressure at varying temperatures (120, 150 and 180 degrees C) for varying durations (2, 6 and 10h). The test results of heat-treated Scots pine and control samples showed that technological properties including compression strength, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength and tension strength perpendicular to grain suffered with heat treatment, and increase in temperature and duration further diminished technological strength values of the wood specimens.

Plasma technologies application for building materials surface modification

NASA Astrophysics Data System (ADS)

Volokitin, G. G.; Skripnikova, N. K.; Volokitin, O. G.; Shehovtzov, V. V.; Luchkin, A. G.; Kashapov, N. F.

2016-01-01

Low temperature arc plasma was used to process building surface materials, such as silicate brick, sand lime brick, concrete and wood. It was shown that building surface materials modification with low temperature plasma positively affects frost resistance, water permeability and chemical resistance with high adhesion strength. Short time plasma processing is rather economical than traditional processing thermic methods. Plasma processing makes wood surface uniquely waterproof and gives high operational properties, dimensional and geometrical stability. It also increases compression resistance and decreases inner tensions level in material.

Safranine fluorescent staining of wood cell walls.

PubMed

Bond, J; Donaldson, L; Hill, S; Hitchcock, K

2008-06-01

Safranine is an azo dye commonly used for plant microscopy, especially as a stain for lignified tissues such as xylem. Safranine fluorescently labels the wood cell wall, producing green/yellow fluorescence in the secondary cell wall and red/orange fluorescence in the middle lamella (ML) region. We examined the fluorescence behavior of safranine under blue light excitation using a variety of wood- and fiber-based samples of known composition to interpret the observed color differentiation of different cell wall types. We also examined the basis for the differences in fluorescence emission using spectral confocal microscopy to examine lignin-rich and cellulose-rich cell walls including reaction wood and decayed wood compared to normal wood. Our results indicate that lignin-rich cell walls, such as the ML of tracheids, the secondary wall of compression wood tracheids, and wood decayed by brown rot, tend to fluoresce red or orange, while cellulose-rich cell walls such as resin canals, wood decayed by white rot, cotton fibers and the G-layer of tension wood fibers, tend to fluoresce green/yellow. This variation in fluorescence emission seems to be due to factors including an emission shift toward red wavelengths combined with dye quenching at shorter wavelengths in regions with high lignin content. Safranine fluorescence provides a useful way to differentiate lignin-rich and cellulose-rich cell walls without counterstaining as required for bright field microscopy.

Mechanical properties evaluation of extruded wood polymer composites

NASA Astrophysics Data System (ADS)

Zaini, A. S. Syah M.; Rus, Anika Zafiah M.; Rahman, Norherman Abdul; Jais, Farhana Hazwanee M.; Fauzan, M. Zarif; Sufian, N. Afiqah

2017-09-01

The rapidly expanding of interest in the manufacture of composite materials from waste industrial and agricultural materials is due to high demand for environmentally friendly materials. Wood polymer composite (WPC) are being used in many type of applications such as in the automobile, electronic, aerospace industry and construction. Therefore, this research study is to determine the mechanical properties behaviour of WPC after an extended Ultra Violet (UV) irradiation exposure. The fabricated sample has been used and to be compared in this research is consists of rice husk, waste fibre and polypropylene (PP) with 4 different types of WPC which are wood block waste (WBW), wood block virgin (WBV), wood sheet (WS) and wood sheet waste (WSW). The extruded specimens were tested for mechanical properties such as strength under compression, puncture strength and impact resistance, and density. In addition, the specimen has been irradiated with the UV exposure at 5000 hours, 10000 hours and 15000 hours. Generally, the mechanical properties the WPC which made from the recycled material were lower than the WPC from virgin material but the density was comparable between the two products after UV irradiation exposure.

The effects of heat treatment on technological properties in Red-bud maple (Acer trautvetteri Medw.) wood.

PubMed

Korkut, Süleyman; Kök, M Samil; Korkut, Derya Sevim; Gürleyen, Tuğba

2008-04-01

Heat treatment is often used to improve the dimensional stability of wood. In this study, the effects of heat treatment on technological properties of Red-bud maple (Acer trautvetteri Medw.) wood were examined. Samples obtained from Düzce Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures (120 degrees C, 150 degrees C and 180 degrees C) and for varying durations (2h, 6h and 10h). The technological properties of heat-treated wood samples and control samples were tested. Compression strength parallel to grain, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength, and tension strength perpendicular to grain were determined. The results showed that technological strength values decreased with increasing treatment temperature and treatment times. Red-bud maple wood could be utilized by using proper heat treatment techniques with minimal losses in strength values in areas where working, and stability such as in window frames, are important factors.

Critical review on the mechanisms of maturation stress generation in trees.

PubMed

Alméras, Tancrède; Clair, Bruno

2016-09-01

Trees control their posture by generating asymmetric mechanical stress around the periphery of the trunk or branches. This stress is produced in wood during the maturation of the cell wall. When the need for reaction is high, it is accompanied by strong changes in cell organization and composition called reaction wood, namely compression wood in gymnosperms and tension wood in angiosperms. The process by which stress is generated in the cell wall during its formation is not yet known, and various hypothetical mechanisms have been proposed in the literature. Here we aim at discriminating between these models. First, we summarize current knowledge about reaction wood structure, state and behaviour relevant to the understanding of maturation stress generation. Then, the mechanisms proposed in the literature are listed and discussed in order to identify which can be rejected based on their inconsistency with current knowledge at the frontier between plant science and mechanical engineering. © 2016 The Author(s).

Understanding the degree of condensation of phenolic and etherified C-9 units of in situ lignins.

PubMed

Nanayakkara, Bernadette; Manley-Harris, Merilyn; Suckling, Ian D

2011-12-14

A novel approach for the quantification of the degree of condensation at the C(5) position of etherified and phenolic phenylpropane (C-9) units of in situ lignin is described. This is achieved by degrading unmethylated and methylated wood by thioacidolysis and analyzing the resultant product mixtures by quantitative (31)P NMR spectroscopy. Applying this new method to compression wood and normal wood from Pinus radiata showed that, whereas 41-47% of etherified guaiacyl C-9 units are condensed at the C(5) position, almost all phenolic guaiacyl C-9 units exist as uncondensed moieties. Analysis of milled wood lignin (MWL) isolated from the same wood by (31)P NMR spectroscopy before and after thioacidolysis showed that the phenolic guaiacyl C-9 units were more condensed than those in the in situ lignin. This is likely due to partial cleavage of the more condensed etherified linkages during the lignin isolation, leading to a relative increase in condensed phenolic guaiacyl C-9 units.

Changes of wood cell walls in response to hygro-mechanical steam treatment.

PubMed

Guo, Juan; Song, Kunlin; Salmén, Lennart; Yin, Yafang

2015-01-22

The effects of compression combined with steam treatment (CS-treatment), i.e. a hygro-mechanical steam treatment on Spruce wood were studied on a cell-structure level to understand the chemical and physical changes of the secondary cell wall occurring under such conditions. Specially, imaging FT-IR microscopy, nanoindentation and dynamic vapour absorption were used to track changes in the chemical structure, in micromechanical and hygroscopic properties. It was shown that CS-treatment resulted in different changes in morphological, chemical and physical properties of the cell wall, in comparison with those under pure steam treatment. After CS-treatment, the cellular structure displayed significant deformations, and the biopolymer components, e.g. hemicellulose and lignin, were degraded, resulting in decreased hygroscopicity and increased mechanical properties of the wood compared to both untreated and steam treated wood. Moreover, CS-treatment resulted in a higher degree of degradation especially in earlywood compared to a more uniform behaviour of wood treated only by steam. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determinants of wood dust exposure in the Danish furniture industry.

PubMed

Mikkelsen, Anders B; Schlunssen, Vivi; Sigsgaard, Torben; Schaumburg, Inger

2002-11-01

This paper investigates the relation between wood dust exposure in the furniture industry and occupational hygiene variables. During the winter 1997-98 54 factories were visited and 2362 personal, passive inhalable dust samples were obtained; the geometric mean was 0.95 mg/m(3) and the geometric standard deviation was 2.08. In a first measuring round 1685 dust concentrations were obtained. For some of the workers repeated measurements were carried out 1 (351) and 2 weeks (326) after the first measurement. Hygiene variables like job, exhaust ventilation, cleaning procedures, etc., were documented. A multivariate analysis based on mixed effects models was used with hygiene variables being fixed effects and worker, machine, department and factory being random effects. A modified stepwise strategy of model making was adopted taking into account the hierarchically structured variables and making possible the exclusion of non-influential random as well as fixed effects. For woodworking, the following determinants of exposure increase the dust concentration: manual and automatic sanding and use of compressed air with fully automatic and semi-automatic machines and for cleaning of work pieces. Decreased dust exposure resulted from the use of compressed air with manual machines, working at fully automatic or semi-automatic machines, functioning exhaust ventilation, work on the night shift, daily cleaning of rooms, cleaning of work pieces with a brush, vacuum cleaning of machines, supplementary fresh air intake and safety representative elected within the last 2 yr. For handling and assembling, increased exposure results from work at automatic machines and presence of wood dust on the workpieces. Work on the evening shift, supplementary fresh air intake, work in a chair factory and special cleaning staff produced decreased exposure to wood dust. The implications of the results for the prevention of wood dust exposure are discussed.

Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters.

PubMed

Chowdhury, S; Maniar, A; Suganya, O M

2015-11-01

In this study, Wood Ash (WA) prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength) of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45) and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20%) including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM), strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters

PubMed Central

Chowdhury, S.; Maniar, A.; Suganya, O.M.

2014-01-01

In this study, Wood Ash (WA) prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength) of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45) and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20%) including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM), strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper. PMID:26644928

Effects of thermal treatment on energy density and hardness of torrefied wood pellets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, Jianghong; Wang, Jingsong; Bi, Xiaotao T.

Here, three types of wood pellets samples, including two types of commercial pellets and one type of lab-made control pellets were torrefied in a fixed bed unit to study the effect of thermal pretreatment on the quality of wood pellets. The quality of wood pellets was mainly characterized by the pellet density, bulk density, higher heating value, Meyer hardness, saturated moisture uptake, volumetric energy density, and energy yield. Results showed that torrefaction significantly decreased the pellet density, hardness, volumetric energy density, and energy yield. The higher heating value increased and the saturated moisture content decreased after torrefaction. In view ofmore » the lower density, lower hardness, lower volumetric energy density, and energy yield of torrefied pellets, it is recommended that biomass should be torrefied and then compressed to make strong pellets of high hydrophobicity and volumetric energy density.« less

Effects of thermal treatment on energy density and hardness of torrefied wood pellets

DOE PAGES

Peng, Jianghong; Wang, Jingsong; Bi, Xiaotao T.; ...

2014-09-27

Here, three types of wood pellets samples, including two types of commercial pellets and one type of lab-made control pellets were torrefied in a fixed bed unit to study the effect of thermal pretreatment on the quality of wood pellets. The quality of wood pellets was mainly characterized by the pellet density, bulk density, higher heating value, Meyer hardness, saturated moisture uptake, volumetric energy density, and energy yield. Results showed that torrefaction significantly decreased the pellet density, hardness, volumetric energy density, and energy yield. The higher heating value increased and the saturated moisture content decreased after torrefaction. In view ofmore » the lower density, lower hardness, lower volumetric energy density, and energy yield of torrefied pellets, it is recommended that biomass should be torrefied and then compressed to make strong pellets of high hydrophobicity and volumetric energy density.« less

Bioplastic composite foam prepared from poly(lactic acid) and natural wood flour

NASA Astrophysics Data System (ADS)

Suwannakas, Pokkes; Petrchwattana, Nawadon; Covavisaruch, Sirijutaratana

2016-03-01

The major drawbacks of Poly(lactic acid) (PLA) bioplastic are its cost and brittleness. This study aims to reduce the cost by foaming PLA reinforced with wood flour. A series of PLA/ natural fiber (WF) composite was prepared by using WF of selected conifers up to 5 wt%; each composite formulation was then foamed using 2 wt% of Azodicarbonamide (ADC) as chemical foaming agent. ADC effectively reduced the density of PLA and the PLA/WF composite foam by about 45% to 0.64 g/cm3 from 1.24 g/cm3 of neat PLA and 1.26 g/cm3 of PLA/WF composites when 2 wt% ADC was applied. Mechanical behaviors in terms of compressive and impact properties were investigated. With the presence of WF, the compressive stress increased with the WF content due to the good interfacial adhesion between the PLA matrix and the WF. This was verified by microscopic observation, leading to efficient stress transfer at the interface between PLA matrix and the WF. The presence of WF raised the specific compressive modulus and strength of PLA/WF composites to around 0.94 GPa.cm3/g and 2.65 MPa.cm3/g but foaming the PLA or the PLA/WF composites led to a dramatic reduction of the compressive modulus to 0.2-0.4 GPa.cm3/g, implying that the PLA and the PLA/WF foams had become softened. This was evidently observed in the significant reduction of hardness coupled with the vast drop of stress required to compressively deform the foams.

Video Data Compression Study for Remote Sensors

DTIC Science & Technology

1976-02-01

Information Tleory, ielnvie, V. Y,, .niar 28-31. [25% T. S, Huang and J, W. Woods, "Picture Bandwitdth Compresston by Linear Transfor- mktion and Block...U.S. DEPARTMENT OF COMMERCE National Technical Information Service AD-A023 845 VIDEO DATA COMPRESSION STUDY FOR REMOTE SENSORS .4 OHIO UNIVERSITY...eport has becn review~ed by the inforxnation Gf filct ; andI is rele’Rroa"v !:r t, e Nation,ýl Terhnilcal Information Service (flTIS) . SAt -w1K, i~: ll

Thermal Transmittance of Porous Hollow Clay Brick by Guarded Hot Box Method

NASA Astrophysics Data System (ADS)

Kim, Joonsoo

2018-03-01

The thermal property of a porous hollow clay brick was determined by measuring the thermal transmittance of the wall made of porous hollow clay bricks. Prior to the production of porous hollow clay bricks, nonporous and porous tiny clay bricks were prepared to determine the physico-mechanical properties by modifying the amount of wood flour and firing temperature. The bricks were produced by uniaxial pressing and then fired in an electric furnace. Their physico-mechanical properties were measured by water absorption, apparent porosity, bulk density, and compressive strength. The porous tiny clay bricks were produced with three types of wood flour: coarse wood flour (1-0.36 mm), medium-sized wood flour (0.36-0.15 mm), and fine wood flour (< 0.08 mm). The thermal transmittance of porous hollow clay bricks was determined through the guarded hot box method, which measures the wall made of porous hollow clay bricks and nonporous cement bricks. The two walls had a thermal transmittance of 1.42 and 2.72 W\\cdot m^{-2}\\cdot K^{-1}, respectively. The difference in thermal transmittance was due to the pores created with fine wood flour (< 0.08 mm) as a pore-forming agent.

Righting response of artificially inclined maritime pine (Pinus pinaster) saplings to wind loading.

PubMed

Berthier, Stephane; Stokes, Alexia

2006-01-01

To determine if trees respond to dynamic and static loading in the same manner, 2-year-old maritime pine (Pinus pinaster Ait.) trees were subjected to different types of mechanical loading in the field. One block of trees (the control) were kept in pots and planted in the field at an angle of 0 or 45 degrees to the vertical. A similar block of leaning potted trees was planted nearby and subjected to frequent, unilateral wind loading for a period of 1 s every 2 min. Half the leaning trees were oriented toward the direction of wind loading and half were oriented along the axis of wind loading. The stem profile was measured three times during the growing season to quantify the rate of stem straightening. Compression wood formation and stem shape were measured in all plants. No differences in mean height or diameter were observed between blocks and all leaning trees straightened, but not at the same rate. Although no difference in the rate of apical straightening occurred between control and wind-treated trees, the righting response of the basal part of the stem of leaning trees subjected to wind was four times greater than that of leaning trees without wind. No differences in the righting response were observed between leaning trees growing toward and trees growing away from the source of wind. No significant differences in compression wood formation were found between control trees and wind-treated trees, indicating that other factors must determine the reorientation rate of leaning trees. Results are discussed with reference to the quality of compression wood in conifers and the mechanotransductive pathway in plants.

Wooden wind turbine blade manufacturing process

DOEpatents

Coleman, Clint

1986-01-01

A wooden wind turbine blade is formed by laminating wood veneer in a compression mold having the exact curvature needed for one side of the blade, following which the other side of the blade is ground flat along its length but twisted with respect to the blade axis.

Experimental determination of the yield stress curve of the scotch pine wood materials

NASA Astrophysics Data System (ADS)

Günay, Ezgi; Aygün, Cevdet; Kaya, Şükrü Tayfun

2013-12-01

Yield stress curve is determined for the pine wood specimens by conducting a series of tests. In this work, pinewood is modeled as a composite material with transversely isotropic fibers. Annual rings (wood grain) of the wood specimens are taken as the major fiber directions with which the strain gauge directions are aligned. For this purpose, three types of tests are arranged. These are tensile, compression and torsion loading tests. All of the tests are categorized with respect to fiber orientations and their corresponding loading conditions. Each test within these categories is conducted separately. Tensile and compression tests are conducted in accordance with standards of Turkish Standards Institution (TSE) whereas torsion tests are conducted in accordance with Standards Australia. Specimens are machined from woods of Scotch pine which is widely used in boat building industries and in other structural engineering applications. It is determined that this species behaves more flexibly than the others. Strain gauges are installed on the specimen surfaces in such a way that loading measurements are performed along directions either parallel or perpendicular to the fiber directions. During the test and analysis phase of yield stress curve, orientation of strain gauge directions with respect to fiber directions are taken into account. The diagrams of the normal stress vs. normal strain or the shear stress vs. shear strain are plotted for each test. In each plot, the yield stress is determined by selecting the point on the diagram, the tangent of which is having a slope of 5% less than the slope of the elastic portion of the diagram. The geometric locus of these selected points constitutes a single yield stress curve on σ1-σ2 principal plane. The resulting yield stress curve is plotted as an approximate ellipse which resembles Tsai-Hill failure criterion. The results attained in this work, compare well with the results which are readily available in the literature.

Lunar Rhythms In Forestry Traditions - Lunar-Correlated Phenomena In Tree Biology And Wood Properties

NASA Astrophysics Data System (ADS)

Zürcher, Ernst

For more than 2000 years, certain forestry practices and rules regarding tree felling have been carried out in observance to Moon cycles. A general review of the different types of rules followed (known in Europe and on other continents and stemming from both written sources and current practitioners) shows that special timber uses are mentioned in relation to a specific felling date which supposedly ensures advantageous wood properties. These empirical forestry traditions apply to a range of wood uses as diverse as building timber, shingles, wooden chimneys, fuel wood, resonance wood for harmony tables of violins, cheese-boxes, barrels and ploughs. In each of these cases, felling at the ``right date'' is thought to be an important factor to ensure the required properties of the product. Moreover, the rafting of timber used to be limited to certain days of the Moon cycle, when the water was supposed to carry the wood in the best way. The second part presents scientific studies concerned, on the one hand, with ``Moon phases'' factor. They deal with elements of tree biology such as germination and initial growth of tropical trees (where strong and systematic variations and their complicating aspects have been observed), insect attacks on trees and reversible fluctuations of stem diameters. On the other hand, some works concentrate on wood properties and the relation between wood and water. They deal with the durability of wood, with systematic density variations after kiln-drying and with variations in the compression strength of the corresponding samples. An overview tries to find a common link between empirical practices and the scientific results.

Design of an Advanced Wood Composite Rotor and Development of Wood Composite Blade Technology

NASA Technical Reports Server (NTRS)

Stroebel, Thomas; Dechow, Curtis; Zuteck, Michael

1984-01-01

In support of a program to advance wood composite wind turbine blade technology, a design was completed for a prototype, 90-foot diameter, two-bladed, one-piece rotor, with all wood/epoxy composite structure. The rotor was sized for compatibility with a generator having a maximum power rating of 4000 kilowatts. Innovative features of the rotor include: a teetering hub to minimize the effects of gust loads, untwisted blades to promote rotor power control through stall, joining of blades to the hub structure via an adhesive bonded structural joint, and a blade structural design which was simplified relative to earlier efforts. The prototype rotor was designed to allow flexibility for configuring the rotor upwind or downwind of the tower, for evaluating various types of teeter dampers and/or elastomeric stops, and with variable delta-three angle settings of the teeter shaft axis. The prototype rotor was also designed with provisions for installing pressure tap and angle of attack instrumentation in one blade. A production version rotor cost analysis was conducted. Included in the program were efforts directed at developing advanced load take-off stud designs for subsequent evaluation testing by NASA, development of aerodynamic tip brake concepts, exploratory testing of a wood/epoxy/graphite concept, and compression testing of wood/epoxy laminate, with scarf-jointed plies.

Pelletizing properties of torrefied spruce

Treesearch

Wolfgang Stelte; Craig Clemons; Jens K. Holm; Anand R. Sanadi; Jesper Ahrenfeldt; Lei Shang; Ulrik B. Henriksen

2011-01-01

Torrefaction is a thermo-chemical conversion process improving the handling, storage and combustion properties of wood. To save storage space and transportation costs, it can be compressed into fuel pellets of high physical and energetic density. The resulting pellets are relatively resistant to moisture uptake, microbiological decay and easy to comminute into small...

Method of making a wooden wind turbine blade

DOEpatents

Coleman, Clint

1984-01-01

A wooden wind turbine blade is formed by laminating wood veneer in a compression mold having the exact curvature needed for one side of the blade, following which the other side of the blade is ground flat along its length but twisted with respect to the blade axis.

Method of making a wooden wind turbine blade

DOEpatents

Coleman, C.

1984-08-14

A wooden wind turbine blade is formed by laminating wood veneer in a compression mold having the exact curvature needed for one side of the blade, following which the other side of the blade is ground flat along its length but twisted with respect to the blade axis. 8 figs.

Earlywood and latewood elastic properties in loblolly pine

Treesearch

Steven Cramer; David Kretschmann; Roderic Lakes; Troy Schmidt

2005-01-01

The elastic properties of earlywood and latewood and their variability were measured in 388 specimens from six loblolly pine trees in a commercial plantation. Properties measured included longitudinal modulus of elasticity, shear modulus, specific gravity, microfibril angle and presence of compression wood. Novel testing procedures were developed to measure properties...

Utilization of modernized global navigation satellite systems for aircraft-based navigation integrity

NASA Astrophysics Data System (ADS)

Ene, Alexandru

The objective of this dissertation is to assess whether or not two particular biocomposite materials, made from hemp fabric and cellulose acetate or polyhydroxybutyrate matrices, are capable of being used for structural and/or construction purposes within in the construction and building industry. The objective of this dissertation was addressed by conducting research to meet the following three goals: (1) to measure the basic mechanical properties of hemp/cellulose acetate and hemp/PHB biocomposites and evaluate if they suitable for use in construction applications, (2) to determine how quickly moisture diffuses into the biocomposite materials and how the moisture affects the mechanical behavior, and (3) to determine how well simple models can predict behavior of structural scale laminates in tension and flexure using biocomposite ply behavior. Compression molding was used to manufacturing the biocomposites from hemp fabric and the themoplastic matrices: cellulose acetate and polyhydroxybutyrate. Four methods for determining the fiber volume fraction were evaluated, and the dissolution method, using different solvents for each matrix type, was used to determine the fiber volume fraction for each composite plate manufactured. Both types of biocomposite were tested in tension, compression, shear, and flexure and the measured properties were compared to wood and engineered wood products to assess whether the biocomposite properties are suitable for use in the construction industry. The biocomposites were conditioned in a humid environment to determine the rate of moisture diffusion into the materials. Then saturated specimens and specimens that were saturated and then dried were tested in tension to evaluate how moisture absorption affects the mechanical behavior of the biocomposites. Finally, simple models of laminate behavior based on laminate plate theory were evaluated to determine if ply level behavior could be used to predict structural scale laminate behavior. While the biocomposite strengths in flexure, compression, and shear were comparable to the strengths of wood and wood-based products parallel to grain, the biocomposite strengths exceeded the strengths perpendicular to the wood grain, as would be expected with fabric reinforcement. The biocomposite moduli of elasticity were between 35% and 75% of the wood moduli parallel to grain. While structural shape of the biocomposites could be manipulated to achieve a comparable structural stiffness to replace wood and short fiber FRPs, the biocomposites have comparable stiffness to the engineered wood-products. Thus, in terms of mechanical properties, the biocomposites can be used in place of engineered-wood products. Yet, the higher densities of the biocomposites as compared to wood and engineered-wood products may limit their implementation in construction. The diffusion coefficients for both biocomposites were comparable to wood and higher than the coefficients for synthetic composites as expected due to the hydrophilicity of the natural fibers. Significantly greater moisture absorption of the hemp/cellulose acetate composite as compared to the hemp/PHB composite was attributed to the cellulose acetate itself being hydrophilic whereas PHB is hydrophobic. The rate of diffusion for both materials was found to increase with increasing temperature. Moisture absorption negatively affected the biocomposites as shown through lower initial stiffnesses and higher strains at failure of saturated specimens. The hemp/cellulose acetate composites were much more affected by moisture absorption than the hemp/PHB composites likely because the moisture plasticized the cellulose acetate and also weakened the interfacial fiber-matrix bond. Moisture was assumed to cause permanent damage because the stress-strain behavior did not return to the unconditioned behavior upon drying of the saturated specimens. The degradation of mechanical properties upon introduction to humid environments limits the potential applications of these biocomposites. For these biocomposites to be used widely within the construction industry, they must therefore be protected from moisture for example through sealants and/or fiber treatments. Classical laminate plate theory was shown to be effective in predicting the initial linear behavior of all of the laminates in tension and flexure, but did not capture stiffness degradation or the full nonlinear stress-strain response of the biocomposites because the model was for linear elastic materials. Use of this model would be appropriate for design of deflection-limited applications within certain stress ranges. The modified nonlinear laminate plate theory predicted the initial stress-strain response well, but at higher strains overestimated the strength and stiffness. The overestimation was attributed to the constitutive model assuming uncoupled stress-strain behavior for each strain component and, additionally in flexure, to the use of tensile behavior as the constitutive behavior in compression. While the simple models provided an adequate prediction of laminate behavior at low strains, to predict behavior at higher strains, it is recommended instead to evaluate the use of finite element analysis to predict response using experimental stress-strain as models for orthotropic materials and non-linear behavior are well-established. (Abstract shortened by UMI.)

Mechanical characterization and structural assessment of biocomposites for construction

NASA Astrophysics Data System (ADS)

Christian, Sarah Jane

The objective of this dissertation is to assess whether or not two particular biocomposite materials, made from hemp fabric and cellulose acetate or polyhydroxybutyrate matrices, are capable of being used for structural and/or construction purposes within in the construction and building industry. The objective of this dissertation was addressed by conducting research to meet the following three goals: (1) to measure the basic mechanical properties of hemp/cellulose acetate and hemp/PHB biocomposites and evaluate if they suitable for use in construction applications, (2) to determine how quickly moisture diffuses into the biocomposite materials and how the moisture affects the mechanical behavior, and (3) to determine how well simple models can predict behavior of structural scale laminates in tension and flexure using biocomposite ply behavior. Compression molding was used to manufacturing the biocomposites from hemp fabric and the themoplastic matrices: cellulose acetate and polyhydroxybutyrate. Four methods for determining the fiber volume fraction were evaluated, and the dissolution method, using different solvents for each matrix type, was used to determine the fiber volume fraction for each composite plate manufactured. Both types of biocomposite were tested in tension, compression, shear, and flexure and the measured properties were compared to wood and engineered wood products to assess whether the biocomposite properties are suitable for use in the construction industry. The biocomposites were conditioned in a humid environment to determine the rate of moisture diffusion into the materials. Then saturated specimens and specimens that were saturated and then dried were tested in tension to evaluate how moisture absorption affects the mechanical behavior of the biocomposites. Finally, simple models of laminate behavior based on laminate plate theory were evaluated to determine if ply level behavior could be used to predict structural scale laminate behavior. While the biocomposite strengths in flexure, compression, and shear were comparable to the strengths of wood and wood-based products parallel to grain, the biocomposite strengths exceeded the strengths perpendicular to the wood grain, as would be expected with fabric reinforcement. The biocomposite moduli of elasticity were between 35% and 75% of the wood moduli parallel to grain. While structural shape of the biocomposites could be manipulated to achieve a comparable structural stiffness to replace wood and short fiber FRPs, the biocomposites have comparable stiffness to the engineered wood-products. Thus, in terms of mechanical properties, the biocomposites can be used in place of engineered-wood products. Yet, the higher densities of the biocomposites as compared to wood and engineered-wood products may limit their implementation in construction. The diffusion coefficients for both biocomposites were comparable to wood and higher than the coefficients for synthetic composites as expected due to the hydrophilicity of the natural fibers. Significantly greater moisture absorption of the hemp/cellulose acetate composite as compared to the hemp/PHB composite was attributed to the cellulose acetate itself being hydrophilic whereas PHB is hydrophobic. The rate of diffusion for both materials was found to increase with increasing temperature. Moisture absorption negatively affected the biocomposites as shown through lower initial stiffnesses and higher strains at failure of saturated specimens. The hemp/cellulose acetate composites were much more affected by moisture absorption than the hemp/PHB composites likely because the moisture plasticized the cellulose acetate and also weakened the interfacial fiber-matrix bond. Moisture was assumed to cause permanent damage because the stress-strain behavior did not return to the unconditioned behavior upon drying of the saturated specimens. The degradation of mechanical properties upon introduction to humid environments limits the potential applications of these biocomposites. For these biocomposites to be used widely within the construction industry, they must therefore be protected from moisture for example through sealants and/or fiber treatments. Classical laminate plate theory was shown to be effective in predicting the initial linear behavior of all of the laminates in tension and flexure, but did not capture stiffness degradation or the full nonlinear stress-strain response of the biocomposites because the model was for linear elastic materials. Use of this model would be appropriate for design of deflection-limited applications within certain stress ranges. The modified nonlinear laminate plate theory predicted the initial stress-strain response well, but at higher strains overestimated the strength and stiffness. The overestimation was attributed to the constitutive model assuming uncoupled stress-strain behavior for each strain component and, additionally in flexure, to the use of tensile behavior as the constitutive behavior in compression. While the simple models provided an adequate prediction of laminate behavior at low strains, to predict behavior at higher strains, it is recommended instead to evaluate the use of finite element analysis to predict response using experimental stress-strain as models for orthotropic materials and non-linear behavior are well-established. (Abstract shortened by UMI.)

Building on Sub-Arctic Soil: Geopolymerization of Muskeg to a Densified Load-Bearing Composite.

PubMed

Waetzig, Gregory R; Cho, Junsang; Lacroix, Max; Banerjee, Sarbajit

2017-11-07

The marshy water-saturated soil typical of the sub-Arctic represents a considerable impediment to the construction of roads, thereby greatly hindering human habitation and geological excavation. Muskeg, the native water-laden topsoil characteristic of the North American sub-Arctic, represents a particularly vexing challenge for road construction. Muskeg must either be entirely excavated, or for direct construction on muskeg, a mix of partial excavation and gradual compaction with the strategic placement of filling materials must be performed. Here, we demonstrate a novel and entirely reversible geopolymerization method for reinforcing muskeg with wood fibers derived from native vegetation with the addition of inorganic silicate precursors and without the addition of extraneous metal precursors. A continuous siloxane network is formed that links together the muskeg, wood fibers, and added silicates yielding a load-bearing and low-subsidence composite. The geopolymerization approach developed here, based on catalyzed formation of a siloxane network with further incorporation of cellulose, allows for an increase of density as well as compressive strength while reducing the compressibility of the composite.

Sodium alginate adhesives as binders in wood fibers/textile waste fibers biocomposites for building insulation.

PubMed

Lacoste, Clément; El Hage, Roland; Bergeret, Anne; Corn, Stéphane; Lacroix, Patrick

2018-03-15

Alginate derived from seaweed is a natural polysaccharide able to form stable gel through carbohydrate functional groups largely used in the food and pharmaceutical industry. This article deals with the use of sodium alginate as an adhesive binder for wood fibres/textile waste fibres biocomposites. Several aldehyde-based crosslinking agents (glyoxal, glutaraldehyde) were compared for various wood/textile waste ratios (100/0, 50/50, 60/40, 70/30 and 0/100 in weight). The fully biomass derived composites whose properties are herewith described satisfy most of the appropriate requirements for building materials. They are insulating with a thermal conductivity in the range 0.078-0.089 W/m/K for an average density in the range 308-333 kg/m3 according to the biocomposite considered. They are semi-rigid with a maximal mechanical strength of 0.84 MPa under bending and 0.44 MPa under compression for 60/40 w/w wood/textile waste biocomposites with a glutaraldehyde crosslinking agent. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Feasibility of Sugar Palm (Arenga pinnata) Trunk for Raw Material of Parquet (Wood Flooring)

NASA Astrophysics Data System (ADS)

Nuryawan, A.; Tarigan, A.; Hakim, L.

2017-03-01

In the market, parquet was made from high density wood such as teak, merbau, kempas, ulin, oak, lime, maple, or other high density wood. Parquet has been used for flooring in specific buildings, for instance sport hall, library, commercial building (i.e hotel lobby, hypermarket), and office building. Because of the scarcity of high density wood nowadays and in order to find out the alternative material for wood flooring, the utilization of sugar palm trunk was considered. In this contribution, unproductive sugar palm tree was cut down and divided into three sections using chain saw, namely bottom, middle, and tip. For each section, physical and mechanical samples testing were made according to British Standard 373:1957 for small clear specimen. Investigation of both properties was done in ambient temperature with at least three replications. Instron UTM (Universal Testing Machine) was used to evaluate the mechanical properties. Results of the physical testing (density, moisture content and tangential shrinkage) showed the entire trunk was suitable for raw material of parquet. However, the results of mechanical testing (hardness, MOE/modulus of elasticity, MOR/modulus of rupture, and compression perpendicular to grain) showed only bottom and middle parts were suitable for raw material of parquet while the upper part was vice versa.

Steam-bending properties of southern pine

Treesearch

Truett J. Lemoine; Peter Koch

1971-01-01

Southern pine wood can be successfully steam-bent if the bending jig incorporates a flexible metal bending strap together with a mechanism to apply a uniform end compression load during the bending operation. With clear, 1/2- and 1-inch-thick southern pine at 17-percent moisture content, highest bending rating where obtained with fast-grown, vertical-grain, low-density...

The Squeeze is On. Grades 6-8.

ERIC Educational Resources Information Center

Rushton, Erik; Ryan, Emily; Swift, Charles

When asked to list some strong materials, people think of steel, concrete, and wood. In this activity, students learn about the force of compression and how it acts on structural components through a hands-on group problem. Using everyday products such as paper, toothpicks, and tape, students construct a structure that will support the weight of a…

Physical and mechanical properties of saligna eucalyptus grown in Hawaii

Treesearch

C.C. Gerhards

1965-01-01

Physical and mechanical properties were determined for saligna eucalyptus (Eucalyptus saligna, Smith) grown in Hawaii. In comparison with wood of the same species grown in Australia, saligna eucalyptus grown in Hawaii was lower in density, shrinkage, and compressive strength parallel to grain; it was about equal in strength in bending and shear; and it was stiffer....

The relation of mechanical properties of wood and nosebar pressure in the production of veneer

Treesearch

Charles W. McMillin

1958-01-01

Observations of checking frequency, depth of check penetration, veneer thickness, and surface quality were made at 20 machining conditions. An inverse relationship between depth of check and frequency of checking was established. The effect of cutting temperature was demonstrated, and strength in compression perpendicular to the grain, tension perpendicular to the...

Micron-scale intra-ring analyses of δ13C in early Eocene Arctic wood from Ellesmere Island

NASA Astrophysics Data System (ADS)

Schubert, B.; Jahren, H.; Eberle, J.; Sternberg, L.

2009-12-01

Early Eocene (ca. 53 Ma) fossil assemblages on Ellesmere Island (75 oN paleolatitude), provide rich information about the plant and animal life of the lush polar ecosystems of the time. Fossil wood recovered from Ellesmere Island is abundant and not permineralized; however, morphological features such as growth rings and resin canals have been obliterated by compression. We report on exceptionally high-resolution intra-ring analyses of δ13C within fossil wood, sampled at ~30 micron intervals across several centimeters of wood sample. Clear patterns in systematic seasonal increases and decreases in wood δ13C allowed us to identify at least 5 annual cycles in the wood. The patterns of increase and decrease in δ13C were consistent with patterns observed for evergreen wood, and distinct from the deciduous patterns we have observed for Metasequoia fossil wood from the middle Eocene (ca. 45 Ma) Arctic site on Axel Heiberg Island. We believe that the high point in the δ13C value of wood seen in each cycle corresponds to the highest environmental temperatures during the annual cycle, as has been seen for modern evergreens (e.g., Barbour et al., 2002). Modern studies have also noted that high temperature periods are correlated with the highest vapor-pressure and soil-water deficits of the annual cycle; these environmental factors would cause the plant to change its discrimination during photosynthesis. We will discuss the relatively low amplitude of δ13C fluctuations (0.5-1.0 ‰) clearly defined by Ellesmere fossil wood, in comparison to observations on modern common evergreens (2.0-4.0 ‰), and speculate that this difference implies greatly dampened seasonal temperature fluctuations in Eocene polar environments, relative to today. Barbour M.M., Walcroft A.S., Farquhar G.D., 2002, Seasonal variation in δ13C and δ18O of cellulose from growth rings of Pinus radiata. Plant, Cell and Environment: v. 25, p. 1483-1499.

Aging and compressibility of municipal solid wastes.

PubMed

Chen, Y M; Zhan, Tony L T; Wei, H Y; Ke, H

2009-01-01

The expansion of a municipal solid waste (MSW) landfill requires the ability to predict settlement behavior of the existing landfill. The practice of using a single compressibility value when performing a settlement analysis may lead to inaccurate predictions. This paper gives consideration to changes in the mechanical compressibility of MSW as a function of the fill age of MSW as well as the embedding depth of MSW. Borehole samples representative of various fill ages were obtained from five boreholes drilled to the bottom of the Qizhishan landfill in Suzhou, China. Thirty-one borehole samples were used to perform confined compression tests. Waste composition and volume-mass properties (i.e., unit weight, void ratio, and water content) were measured on all the samples. The test results showed that the compressible components of the MSW (i.e., organics, plastics, paper, wood and textiles) decreased with an increase in the fill age. The in situ void ratio of the MSW was shown to decrease with depth into the landfill. The compression index, Cc, was observed to decrease from 1.0 to 0.3 with depth into the landfill. Settlement analyses were performed on the existing landfill, demonstrating that the variation of MSW compressibility with fill age or depth should be taken into account in the settlement prediction.

JPRS Report, Science & Technology, China: Energy.

DTIC Science & Technology

1988-02-10

bedrock growth anticlines, buried hill fault blocks, rolling anticlines, compression anticlines, draped anticlines, volcanic diapers and others. The...development and utilization of solar , wind, geothermal and other energy resources, the energy conservation capacity and newly-added energy resources were...equivalent to 20 million tons of standard coal. The firewood-saving capacity in wood and coal-saving stoves, biogas pits and solar cookers alone was

Nose Fairing Modeling and Simulation to Support Trident II D5 Lifecycle Extension

DTIC Science & Technology

2013-09-01

Rupture Flexural Modulus Flexural Yield strength Compressive Yield strength Poissons Ratio Machinabi lily Shear strength Impact Work to...Categories: Ceramic; Glass; Glass Fiber , other Engineeting Material; C<>mposite Rbers Material Notes: Used as a reinforcing agent in fiber glass compos~es...MATWEB AMERICAN SITKA SPRUCE WOOD .......................35 APPENDIX B. MATWEB E–GLASS FIBER , GENERIC ......................................37 APPENDIX

A survey of size-fractionated dust levels in the U.S. wood processing industry.

PubMed

Kalliny, Medhat I; Brisolara, Joseph A; Glindmeyer, Henry; Rando, Roy

2008-08-01

A survey of size-fractionated dust exposure was carried out in 10 wood processing plants across the United States as part of a 5-year longitudinal respiratory health study. The facilities included a sawmill, plywood assembly plants, secondary wood milling operations, and factories producing finished wood products such as wood furniture and cabinets. Size-fractionated dust exposures were determined using the RespiCon Personal Particle Sampler. There were 2430 valid sets of respirable, thoracic, and inhalable dust samples collected. Overall, geometric mean (geometric standard deviation) exposure levels were found to be 1.44 (2.67), 0.35 (2.65), and 0.18 (2.54) mg/m, for the inhalable, thoracic, and respirable fractions, respectively. Averaged across all samples, the respirable fraction accounted for 16.7% of the inhalable dust mass, whereas the corresponding figure for thoracic fraction as a percentage of the inhalable fraction was 28.7%. Exposures in the furniture manufacturing plants were significantly higher than those in sawmill and plywood assembly plants, wood milling plants, and cabinet manufacturing plants, whereas the sawmill and plywood assembly plants exhibited significantly lower dust levels than the other industry segments. Among work activities, cleaning with compressed air and sanding processes produced the highest size-fractionated dust exposures, whereas forklift drivers demonstrated the lowest respirable and inhalable dust fractions and shipping processes produced the lowest thoracic dust fraction. Other common work activities such as sawing, milling, and clamping exhibited intermediate exposure levels, but there were significant differences in relative ranking of these across the various industry segments. Processing of hardwood and mixed woods generally were associated with higher exposures than were softwood and plywood, although these results were confounded with industry segment also.

Determinants of Wood Dust Exposure in the Danish Furniture Industry—Results from Two Cross-Sectional Studies 6 Years Apart

PubMed Central

Schlünssen, Vivi; Jacobsen, Gitte; Erlandsen, Mogens; Mikkelsen, Anders B.; Schaumburg, Inger; Sigsgaard, Torben

2008-01-01

Objectives: This paper investigates determinants of wood dust exposure and trends in dust level in the furniture industry of Viborg County, Denmark, using data from two cross-sectional studies 6 years apart. Methods: During the winter 1997/1998, 54 factories were visited (hereafter study 1). In the winter 2003/2004, 27 factories were revisited, and personal dust measurements were repeated. In addition, 14 new factories were included (hereafter study 2). A total of 2303 woodworkers participated in study 1, and 2358 measurements from 1702 workers were available. From study 2, 1581 woodworkers participated and 1355 measurements from 1044 workers were available. Information on occupational variables describing potential determinants of exposures like work task, exhaust ventilation, enclosure and cleaning procedures were collected. A total of 2627 measurements and 1907 persons were included in the final mixed model in order to explore determinants of exposure and trends in dust level. Results: The overall inhalable wood dust concentration (geometric means (geometric standard deviation)) has decreased from 0.95 mg/m3 (2.05) in study 1 to 0.60 mg/m3 (1.63) in study 2, representing a 7% annual decrease in dust concentration, which was confirmed in the mixed model. From study 1 to study 2 there has been a change towards less manual work and more efficient cleaning methods, but on the contrary also more inadequate exhaust ventilation systems. The following determinants were found to ‘increase’ dust concentration: sanding; use of compressed air; use of full-automatic machines; manual work; cleaning of work pieces with compressed air; kitchen producing factories and small factories (<20 employees). The following determinants of exposure were found to ‘decrease’ dust concentration: manual assembling/packing; sanding with adequate exhaust ventilation; adequate exhaust ventilation; vacuum cleaning of machines and special cleaning staff. Conclusions: Despite a substantial drop in the dust concentration during the last 6 years in the furniture industry in Viborg County, further improvements are possible. There should be more focus on improved exhaust ventilation, professional cleaning methods and avoiding use of compressed air. PMID:18407937

Determinants of wood dust exposure in the Danish furniture industry--results from two cross-sectional studies 6 years apart.

PubMed

Schlünssen, Vivi; Jacobsen, Gitte; Erlandsen, Mogens; Mikkelsen, Anders B; Schaumburg, Inger; Sigsgaard, Torben

2008-06-01

This paper investigates determinants of wood dust exposure and trends in dust level in the furniture industry of Viborg County, Denmark, using data from two cross-sectional studies 6 years apart. During the winter 1997/1998, 54 factories were visited (hereafter study 1). In the winter 2003/2004, 27 factories were revisited, and personal dust measurements were repeated. In addition, 14 new factories were included (hereafter study 2). A total of 2303 woodworkers participated in study 1, and 2358 measurements from 1702 workers were available. From study 2, 1581 woodworkers participated and 1355 measurements from 1044 workers were available. Information on occupational variables describing potential determinants of exposures like work task, exhaust ventilation, enclosure and cleaning procedures were collected. A total of 2627 measurements and 1907 persons were included in the final mixed model in order to explore determinants of exposure and trends in dust level. The overall inhalable wood dust concentration (geometric means (geometric standard deviation)) has decreased from 0.95 mg/m(3) (2.05) in study 1 to 0.60 mg/m(3) (1.63) in study 2, representing a 7% annual decrease in dust concentration, which was confirmed in the mixed model. From study 1 to study 2 there has been a change towards less manual work and more efficient cleaning methods, but on the contrary also more inadequate exhaust ventilation systems. The following determinants were found to 'increase' dust concentration: sanding; use of compressed air; use of full-automatic machines; manual work; cleaning of work pieces with compressed air; kitchen producing factories and small factories (<20 employees). The following determinants of exposure were found to 'decrease' dust concentration: manual assembling/packing; sanding with adequate exhaust ventilation; adequate exhaust ventilation; vacuum cleaning of machines and special cleaning staff. Despite a substantial drop in the dust concentration during the last 6 years in the furniture industry in Viborg County, further improvements are possible. There should be more focus on improved exhaust ventilation, professional cleaning methods and avoiding use of compressed air.

Delignified and Densified Cellulose Bulk Materials with Excellent Tensile Properties for Sustainable Engineering.

PubMed

Frey, Marion; Widner, Daniel; Segmehl, Jana S; Casdorff, Kirstin; Keplinger, Tobias; Burgert, Ingo

2018-02-07

Today's materials research aims at excellent mechanical performance in combination with advanced functionality. In this regard, great progress has been made in tailoring the materials by assembly processes in bottom-up approaches. In the field of wood-derived materials, nanocellulose research has gained increasing attention, and materials with advanced properties were developed. However, there are still unresolved issues concerning upscaling for large-scale applications. Alternatively, the sophisticated hierarchical scaffold of wood can be utilized in a top-down approach to upscale functionalization, and one can profit at the same time from its renewable nature, CO 2 storing capacity, light weight, and good mechanical performance. Nevertheless, for bulk wood materials, a wider multipurpose industrial use is so far impeded by concerns regarding durability, natural heterogeneity as well as limitations in terms of functionalization, processing, and shaping. Here, we present a novel cellulose bulk material concept based on delignification and densification of wood resulting in a high-performance material. A delignification process using hydrogen peroxide and acetic acid was optimized to delignify the entire bulk wooden blocks and to retain the highly beneficial structural directionality of wood. In a subsequent step, these cellulosic blocks were densified in a process combining compression and lateral shear to gain a very compact cellulosic material with entangled fibers while retaining unidirectional fiber orientation. The cellulose bulk materials obtained by different densification protocols were structurally, chemically, and mechanically characterized revealing superior tensile properties compared to native wood. Furthermore, after delignification, the cellulose bulk material can be easily formed into different shapes, and the delignification facilitates functionalization of the bioscaffold.

Cambium

NASA Technical Reports Server (NTRS)

Savidge, Rodney

2009-01-01

The Cambium investigation is one in a pair of investigations which utilizes the Advanced Biological Research System (ABRS). Cambium seeks definitive evidence that gravity has a direct effect on cambial cells (cells located under the inner bark where secondary growth occurs) in willow, Salix babylonica. The Cambium investigation uses willow plants flown on the International Space Station to better understand the fundamental processes by which plants produce cellulose and lignin, the two main structural materials found in plant matter. On Earth, the nature of wood within tree stems varies depending on position, and that within-tree variation includes differences in cell types and chemistry including lignin and cellulose, two major components of wood influencing wood strength, usefulness and carbon content. Reaction wood is an extreme example of such variation, and it is believed that reaction wood develops as a reaction to the influence of gravity. For the Cambium experiment, young willow plants will be launched to the ISS where their stems will be looped in an attempt to induce reaction wood formation. After on-orbit growth, the plants will be preserved and returned to Earth for analysis. Understanding the role of gravity in wood formation is expected to enable wiser management of forests for carbon sequestration as well as better utilization of trees for wood products. Detailed Research Description: The Cambium experiment will provide an understanding of physiological processes such as gene expression, metabolism and general plant development that are affected in plant systems exposed to space flight. Cambium seeks definitive evidence that gravity has a direct effect on the cambial cells (cells located under the inner bark where secondary growth occurs) that contribute to xylogenesis (reaction wood formation) in willow plants, Salix babylonica. Tension wood fibers differentiate on the upper sides of stems when the stem is altered from its normal (vertical) growth position by looping. This reaction wood response does not occur if the orientation of the plant stem with respect to gravity is not altered. If a localized zone of tension wood should be formed in looped stems under microgravity conditions, this would be the first conclusive evidence that gravity is not required. On the other hand, if a zone of tension wood is not produced in looped stems (subjected to tension on one side, compression on the other) in microgravity, this would be the first definitive evidence that gravity has a direct effect on the cambial cells which contribute to reaction wood formation. Following return to Earth the plants will be analyzed by microscopy and chemical methods.

Transcriptome profiling of radiata pine branches reveals new insights into reaction wood formation with implications in plant gravitropism.

PubMed

Li, Xinguo; Yang, Xiaohui; Wu, Harry X

2013-11-08

Formation of compression (CW) and opposite wood (OW) in branches and bent trunks is an adaptive feature of conifer trees in response to various displacement forces, such as gravity, wind, snow and artificial bending. Several previous studies have characterized tracheids, wood and gene transcription in artificially or naturally bent conifer trunks. These studies have provided molecular basis of reaction wood formation in response to bending forces and gravity stimulus. However, little is known about reaction wood formation and gene transcription in conifer branches under gravity stress. In this study SilviScan® technology was used to characterize tracheid and wood traits in radiate pine (Pinus radiata D. Don) branches and genes differentially transcribed in CW and OW were investigated using cDNA microarrays. CW drastically differed from OW in tracheids and wood traits with increased growth, thicker tracheid walls, larger microfibril angle (MFA), higher density and lower stiffness. However, CW and OW tracheids had similar diameters in either radial or tangential direction. Thus, gravity stress largely influenced wood growth, secondary wall deposition, cellulose microfibril orientation and wood properties, but had little impact on primary wall expansion. Microarray gene transcription revealed about 29% of the xylem transcriptomes were significantly altered in CW and OW sampled in both spring and autumn, providing molecular evidence for the drastic variation in tracheid and wood traits. Genes involved in cell division, cellulose biosynthesis, lignin deposition, and microtubules were mostly up-regulated in CW, conferring its greater growth, thicker tracheid walls, higher density, larger MFA and lower stiffness. However, genes with roles in cell expansion and primary wall formation were differentially transcribed in CW and OW, respectively, implicating their similar diameters of tracheid walls and different tracheid lengths. Interestingly, many genes related to hormone and calcium signalling as well as various environmental stresses were exclusively up-regulated in CW, providing important clues for earlier molecular signatures of reaction wood formation under gravity stimulus. The first comprehensive investigation of tracheid characteristics, wood properties and gene transcription in branches of a conifer species revealed more accurate and new insights into reaction wood formation in response to gravity stress. The identified differentially transcribed genes with diverse functions conferred or implicated drastic CW and OW variation observed in radiata pine branches. These genes are excellent candidates for further researches on the molecular mechanisms of reaction wood formation with a view to plant gravitropism.

Tectonic setting of the Wooded Island earthquake swarm, eastern Washington

USGS Publications Warehouse

Blakely, Richard J.; Sherrod, Brian L.; Weaver, Craig S.; Rohay, Alan C.; Wells, Ray E.

2012-01-01

Magnetic anomalies provide insights into the tectonic implications of a swarm of ~1500 shallow (~1 km deep) earthquakes that occurred in 2009 on the Hanford site,Washington. Epicenters were concentrated in a 2 km2 area nearWooded Island in the Columbia River. The largest earthquake (M 3.0) had first motions consistent with slip on a northwest-striking reverse fault. The swarm was accompanied by 35 mm of vertical surface deformation, seen in satellite interferometry (InSAR), interpreted to be caused by ~50 mm of slip on a northwest-striking reverse fault and associated bedding-plane fault in the underlying Columbia River Basalt Group (CRBG). A magnetic anomaly over exposed CRBG at Yakima Ridge 40 km northwest of Wooded Island extends southeastward beyond the ridge to the Columbia River, suggesting that the Yakima Ridge anticline and its associated thrust fault extend southeastward in the subsurface. In map view, the concealed anticline passes through the earthquake swarm and lies parallel to reverse faults determined from first motions and InSAR data. A forward model of the magnetic anomaly near Wooded Island is consistent with uplift of concealed CRBG, with the top surface <200 m below the surface. The earthquake swarm and the thrust and bedding-plane faults modeled from interferometry all fall within the northeastern limb of the faulted anticline. Although fluids may be responsible for triggering the Wooded Island earthquake swarm, the seismic and aseismic deformation are consistent with regional-scale tectonic compression across the concealed Yakima Ridge anticline.

The hierarchical structure and mechanics of plant materials.

PubMed

Gibson, Lorna J

2012-11-07

The cell walls in plants are made up of just four basic building blocks: cellulose (the main structural fibre of the plant kingdom) hemicellulose, lignin and pectin. Although the microstructure of plant cell walls varies in different types of plants, broadly speaking, cellulose fibres reinforce a matrix of hemicellulose and either pectin or lignin. The cellular structure of plants varies too, from the largely honeycomb-like cells of wood to the closed-cell, liquid-filled foam-like parenchyma cells of apples and potatoes and to composites of these two cellular structures, as in arborescent palm stems. The arrangement of the four basic building blocks in plant cell walls and the variations in cellular structure give rise to a remarkably wide range of mechanical properties: Young's modulus varies from 0.3 MPa in parenchyma to 30 GPa in the densest palm, while the compressive strength varies from 0.3 MPa in parenchyma to over 300 MPa in dense palm. The moduli and compressive strength of plant materials span this entire range. This study reviews the composition and microstructure of the cell wall as well as the cellular structure in three plant materials (wood, parenchyma and arborescent palm stems) to explain the wide range in mechanical properties in plants as well as their remarkable mechanical efficiency.

The hierarchical structure and mechanics of plant materials

PubMed Central

Gibson, Lorna J.

2012-01-01

The cell walls in plants are made up of just four basic building blocks: cellulose (the main structural fibre of the plant kingdom) hemicellulose, lignin and pectin. Although the microstructure of plant cell walls varies in different types of plants, broadly speaking, cellulose fibres reinforce a matrix of hemicellulose and either pectin or lignin. The cellular structure of plants varies too, from the largely honeycomb-like cells of wood to the closed-cell, liquid-filled foam-like parenchyma cells of apples and potatoes and to composites of these two cellular structures, as in arborescent palm stems. The arrangement of the four basic building blocks in plant cell walls and the variations in cellular structure give rise to a remarkably wide range of mechanical properties: Young's modulus varies from 0.3 MPa in parenchyma to 30 GPa in the densest palm, while the compressive strength varies from 0.3 MPa in parenchyma to over 300 MPa in dense palm. The moduli and compressive strength of plant materials span this entire range. This study reviews the composition and microstructure of the cell wall as well as the cellular structure in three plant materials (wood, parenchyma and arborescent palm stems) to explain the wide range in mechanical properties in plants as well as their remarkable mechanical efficiency. PMID:22874093

Effect of processing method on the mechanical and thermal of Silvergrass/HDPE composites

NASA Astrophysics Data System (ADS)

Liu, Bing; Jin, Yueqiang; Wang, Shuying

2017-05-01

This paper investigates the effect of compression and injection molding methods on properties of Silvergrass-HDPE (High Density Polyethylene) composites, with respect to mechanical behaviors. Maleated polyethylene (MAPE) was added in the composite and improved the mechanical property of the composite. The research founds MAPE can improve the mechanical property because it improved the interfacial compatibility as a coupling agent. When added a content of 8% of MAPE, Silvergrass-HDPE composites made from compression molding shows a better mechanical performance in tensile strength and flexural strength than that made from injection molding, with increasing Silvergrass fiber content from 30% to 50%. However, the WPCs (wood plastics composites) made from injection molding had a lower degree of crystallinity with or without MAPE treatment.

Chemical, ultrastructural and supramolecular analysis of tension wood in Populus tremula x alba as a model substrate for reduced recalcitrance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foston, Marcus B; Hubbell, Christopher A; Samuel, Reichel

2011-01-01

Biomass is one of the most abundant potential sustainable sources for fuel and material production, however to fully realize this potential an improved understanding of lignocellulosic recalcitrance must be developed. In an effort to appreciate the underlying phenotypic, biochemical and morphological properties associated with the reduced recalcitrance observed in tension stress-induced reaction wood, we report the increased enzymatic sugar yield and corresponding chemical and ultrastructural properties of Populus tension wood. Populus tremula x alba (PTA) was grown under tension and stem segments containing three different wood types: normal wood (NW), tension wood (TW) from the elongated stem side and oppositemore » wood (OW) from the compressed stem side were collected. A variety of analytical techniques were used to describe changes occurring as a result of the tension stress-induced formation of a gelatinous cell wall layer (G-layer). For example, gel permeation chromatography (GPC) and 13C solid-state nuclear magnetic resonance (NMR) revealed that the molecular weight and crystallinity of cellulose in TW is greater than that of cellulose acquired from NW. Whole cell ionic liquid and other solid-state NMR analysis detailed the structure of lignin and hemicellulose in the samples, detecting the presence of variations in lignin and hemicellulose sub-units, linkages and semi-quantitatively estimating the relative amounts of syringyl (S), guaiacyl (G) and p-hydroxybenzoate (PB) monolignol units. It was confirmed that TW displayed an increase in PB or H-like lignin and S to G ratio from 1.25 to 1.50 when compared to the NW sample. Scanning electron microscopy (SEM) and coherent anti-Stokes Raman scattering (CARS) were also used to evaluate the morphology and corresponding spatial distribution of the major lignocellulosic components. We found changes in a combination of cell wall properties appear to influence recalcitrance more than any single factor alone.« less

Metal/ceramic composites via infiltration of an interconnected wood-derived ceramic

NASA Astrophysics Data System (ADS)

Wilkes, Thomas E.

The use of composites is increasing as they afford scientists and engineers the ability to combine the advantageous properties of each constituent phase, e.g. metal ductility and ceramic stiffness. With respect to materials design, biomimetics is garnering increasing attention due to the complex, yet efficient, natural microstructures. One such biomimetic, or in this case 'bio-derived,' curiosity is wood-derived ceramic, which is made by either replicating or converting wood into a ceramic. The resulting porous and anisotropic material retains the precursor microstructure. The wide variety of precursors can yield materials with a range of pore sizes and distribution of pores. The purpose of this work was to study the processing, microstructure, and properties of aluminum/silicon carbide composites. The composites were made by infiltrating molten aluminum into porous wood-derived SIC, which was produced by the reactive melt-infiltration of silicon into pyrolyzed wood. The composite microstructure consisted of interconnected SiC surrounding Al-alloy 'fibers.' The strength, modulus, and toughness were measured in both longitudinal and transverse orientations. The Al → SiC load transfer was investigated with high-energy X-ray diffraction in combination with in-situ compressive loading. The properties in flexure were found to decrease with increasing temperature. Despite the complex microstructure, predictions of the composite flexural modulus and longitudinal fracture toughness were obtained using simple models: Halpin-Tsai bounds and the Ashby et al. model of the effect of ductile particle-reinforcements on the toughness of brittle materials (Ashby et al. 1989), respectively. In addition, the Al/SiC research inspired the investigation of carbon-reinforced copper composites. The goal was to explore the feasibility of making a high-thermal conductivity composite by infiltrating copper into wood-derived carbon. Results indicated that Cu/C composites could be made with pressurized infiltration, but the predicted thermal conductivity was low due to the amorphous wood-derived carbon.

Cultural Resources Inventory of the Montz Freshwater Diversion Project Corridor, St. Charles Parish, Louisiana. Volume 1.

DTIC Science & Technology

1986-06-23

to St. Louis Cathedral; they did so, again citing health hazards . However, in 1846, Wood built a cotton compress at the location despite the presence...price of meat has always been low, and that the artificial restrictions of commerce have prevented the development of other outlets (Robin 1966:114...relationships among the variables. The cultural resource professional will avoid pigeon -holing data gathering operations into unalterable research

Restoration of Wavelet-Compressed Images and Motion Imagery

DTIC Science & Technology

2004-01-01

SECURITY CLASSIFICATION OF REPORT UNCLASSIFIED 18. SECURITY CLASSIFICATION OF THIS PAGE UNCLASSIFIED 19. SECURITY CLASSIFICATION...images is that they are global translates of each other, where 29 the global motion parameters are known. In a very simple sense , these five images form...Image Proc., vol. 1, Oct. 2001, pp. 185–188. [2] J. W. Woods and T. Naveen, “A filter based bit allocation scheme for subband compresion of HDTV,” IEEE

2007 Program of Study: Boundary Layers

DTIC Science & Technology

2008-06-01

Compressible Fluid: 3He near Tc. Phys. Rev. Let. 82, 4635-4638. [13] Onuki , A., Hao, H ., and Ferrell, R. A. 1990 Fast adiabatic equilibration in a...Supérieure H . Joseph Fernando Arizona State University Glenn Flierl Massachusetts Institute of Technology Rockwell Geyer Woods Hole Oceanographic...which is controlled by the free fluid, yet which in turn give the free movement its characteristic stamp by the emission of vortex sheets. ( H . Rouse and S

Leaves Waste Composite with Glass Fiber Reinforcement

NASA Astrophysics Data System (ADS)

Khoiri, N.; Jannah, W. N.; Huda, C.; Maulana, RM; Marwoto, P.; Masturi

2018-03-01

A research has been made to fabricate leave waste composites and Polyvinyl Acetate (PvAc) polymers reinforced with glass fibers. The method used was a simple mixing of leaves powders, PvAc, and glass fibers varied from 0 g to 1 g. Mass of 16 g leaves powder and mass of PvAc 4 g. The mixing result is suppressed by 5 metric-tons for 15 minutes. The composite is dried at room temperature for 1 day then in the oven at 100°C for 1 hour. The compressive strength is measured bu a hydraulic press. The result show that the compressive strength increased to the highest point of 0.8 g and will decrease significantly when the addition of glass fiber mass of 1 g. The highest compressive strength reaches 52.6 MPa when the glass fiber mass is 0.8 g. The result of this research showed that leaves composites with Polyvinyl Acetate polymer reinforced with fiber glass can be used as alternative material of wood substitute.

Furfural production from Eucalyptus wood using an Acidic Ionic Liquid.

PubMed

Peleteiro, Susana; Santos, Valentín; Garrote, Gil; Parajó, Juan Carlos

2016-08-01

Eucalyptus globulus wood samples were treated with hot, compressed water to separate hemicelluloses (as soluble saccharides) from a solid phase mainly made up of cellulose and lignin. The liquid phase was dehydrated, and the resulting solids (containing pentoses as well as poly- and oligo- saccharides made up of pentoses) were dissolved and reacted in media containing an Acidic Ionic Liquid (1-butyl-3-methylimidazolium hydrogen sulfate) and a co-solvent (dioxane). The effects of the reaction time on the product distribution were studied at temperatures in the range 120-170°C for reaction times up to 8h, and operational conditions leading to 59.1% conversion of the potential substrates (including pentoses and pentose structural units in oligo- and poly- saccharides) into furfural were identified. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of biochar from food and wood waste as green admixture for cement mortar.

PubMed

Gupta, Souradeep; Kua, Harn Wei; Koh, Hui Jun

2018-04-01

Landfilling of food waste due to its low recycling rate is raising serious concerns because of associated soil and water contamination, and emission of methane and other greenhouse gases during the degradation process. This paper explores feasibility of using biochar derived from mixed food waste (FWBC), rice waste (RWBC) and wood waste (mixed wood saw dust, MWBC) as carbon sequestering additive in mortar. RWBC is prepared from boiled plain rice, while FWBC is prepared from combination of rice, meat, and vegetables in fixed proportion. Carbon content in FWBC, RWBC and MWBC were found to be 71%, 66% and 87% by weight respectively. Results show that addition of 1-2wt% of FWBC and RWBC in mortar results in similar mechanical strength as control mix (without biochar). 1wt% of FWBC led to 40% and 35% reduction in water penetration and sorptivity respectively, indicating higher impermeability of mortar. Biochar from mixed wood saw dust performed better in terms of mechanical and permeability properties. Increase in compressive strength and tensile strength by up to 20% was recorded, while depth of water penetration and sorptivity was reduced by about 60% and 38% respectively compared to control. Both FWBC and MWBC were found to act as reinforcement to mortar paste, which resulted in higher ductility than control at failure under flexure. This study suggests that biochar from food waste and mixed wood saw dust has the potential to be successfully deployed as additive in cement mortar, which would also promote waste recycling, and sequester high volume carbon in civil infrastructure. Copyright © 2017 Elsevier B.V. All rights reserved.

On the role of CFRP reinforcement for wood beams stiffness

NASA Astrophysics Data System (ADS)

Ianasi, A. C.

2015-11-01

In recent years, carbon fiber composites have been increasingly used in different ways in reinforcing structural elements. Specifically, the use of composite materials as a reinforcement for wood beams under bending loads requires paying attention to several aspects of the problem such as the number of the composite layers applied on the wood beams. Study consolidation of composites revealed that they are made by bonding fibrous material impregnated with resin on the surface of various elements, to restore or increase the load carrying capacity (bending, cutting, compression or torque) without significant damage of their rigidity. Fibers used in building applications can be fiberglass, aramid or carbon. Items that can be strengthened are concrete, brick, wood, steel and stone, and in terms of structural beams, walls, columns and floors. This paper describes an experimental study which was designed to evaluate the effect of composite material on the stiffness of the wood beams. It proposes a summary of the fundamental principles of analysis of composite materials and the design and use. The type of reinforcement used on the beams is the carbon fiber reinforced polymer (CFRP) sheet and plates and also an epoxy resin for bonding all the elements. Structural epoxy resins remain the primary choice of adhesive to form the bond to fiber-reinforced plastics and are the generally accepted adhesives in bonded CFRP-wood connections. The advantages of using epoxy resin in comparison to common wood-laminating adhesives are their gap-filling qualities and the low clamping pressures that are required to form the bond between carbon fiber plates or sheets and the wood beams. Mechanical tests performed on the reinforced wood beams showed that CFRP materials may produce flexural displacement and lifting increases of the beams. Observations of the experimental load-displacement relationships showed that bending strength increased for wood beams reinforced with CFRP composite plates and sheets compared to those without CFRP reinforcement. The main conclusion of the tests is that the tensioning forces allow beam taking a maximum load for a while, something that is particularly useful when we consider a real construction, so in case of excess lift beam, we have time to take strengthening measures and when is about a catastrophic request (earthquake) the construction remain partially functional. The experiments have shown that the method of increasing resistance of wood constructions with composite materials is good for it. The solution is easy to implement and has low costs.

Size, shape and flow characterization of ground wood chip and ground wood pellet particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rezaei, Hamid; Lim, C. Jim; Lau, Anthony

Size, shape and density of biomass particles influence their transportation, fluidization, rates of drying and thermal decomposition. Pelleting wood particles increases the particle density and reduces the variability of physical properties among biomass particles. In this study, pine chips prepared for pulping and commercially produced pine pellets were ground in a hammer mill using grinder screens of 3.2, 6.3, 12.7 and 25.4mmperforations. Pellets consumed about 7 times lower specific grinding energy than chips to produce the same size of particles. Grinding pellets produced the smaller particles with narrower size distribution than grinding chips. Derived shape factors in digital image analysismore » showed that chip particles were rectangular and had the aspect ratios about one third of pellet particles. Pellet particles were more circular shape. The mechanical sieving underestimated the actual particle size and did not represent the size of particles correctly. Instead, digital imaging is preferred. Angle of repose and compressibility tests represented the flow properties of ground particles. Pellet particles made a less compacted bulk, had lower cohesion and did flow easier in a pile of particles. In conclusion, particle shape affected the flow properties more than particle size« less

Size, shape and flow characterization of ground wood chip and ground wood pellet particles

DOE PAGES

Rezaei, Hamid; Lim, C. Jim; Lau, Anthony; ...

2016-07-11

Size, shape and density of biomass particles influence their transportation, fluidization, rates of drying and thermal decomposition. Pelleting wood particles increases the particle density and reduces the variability of physical properties among biomass particles. In this study, pine chips prepared for pulping and commercially produced pine pellets were ground in a hammer mill using grinder screens of 3.2, 6.3, 12.7 and 25.4mmperforations. Pellets consumed about 7 times lower specific grinding energy than chips to produce the same size of particles. Grinding pellets produced the smaller particles with narrower size distribution than grinding chips. Derived shape factors in digital image analysismore » showed that chip particles were rectangular and had the aspect ratios about one third of pellet particles. Pellet particles were more circular shape. The mechanical sieving underestimated the actual particle size and did not represent the size of particles correctly. Instead, digital imaging is preferred. Angle of repose and compressibility tests represented the flow properties of ground particles. Pellet particles made a less compacted bulk, had lower cohesion and did flow easier in a pile of particles. In conclusion, particle shape affected the flow properties more than particle size« less

Genetic and environmental modification of the mechanical properties of wood

NASA Astrophysics Data System (ADS)

Sederoff, R.; Allona, I.; Whetten, R.

1996-02-01

Wood is one of the nation's leading raw materials and is used for a wide variety of products, either directly as wood, or as derived materials in pulp and paper. Wood is a biological material and evolved to provide mechanical support and water transport to the early plants that conquered the land. Wood is a tissue that results from the differentiation and programmed cell death of cells that derive from a tissue known as the vascular cambium. The vascular cambium is a thin cylinder of undifferentiated tissue in plant stems and roots that gives rise to several different cell types. Cells that differentiate on the internal side of the cambium form xylem, a tissue composed in major part, of long thin cells that die leaving a network of interconnected cell walls that serve to transport water and to provide mechanical support for the woody plant. The shape and chemical composition of the cells in xylem are well suited for these functions. The structure of cells in xylem determines the mechanical properties of the wood because of the strength derived from the reinforced matrix of the wall. The hydrophobic phenolic surface of the inside of the cell walls is essential to maintain surface tension upon which water transport is based and to resist decay caused by microorganisms. The properties of wood derived from the function of xylem also determine its structural and chemical properties as wood and paper products. Therefore, the physical and chemical properties of wood and paper products also depend on the morphology and composition of the cells from which they are derived. Wood (xylem cell walls) is an anisotropic material, a composite of lignocellulose. It is a matrix of cellulose microfibrils, complexed with hemicelluloses, (carbohydrate polymers which contain sugars other than glucose, both pentoses and hexoses), embedded together in a phenolic matrix of lignin. The high tensile strength of wood in the longitudinal direction, is due to the structure of cellulose and the orientation of the cellulose microfibrils. Lignin provides the embedding matrix that imparts compressive strength and flexibility. The water conducting cells in xylem, the tracheids, are long thin cells, which become the fibers of paper when the lignin is removed from wood during the papermaking process. The length of the tracheids and the thickness of the walls have important effects on the properties of paper that is produced. The past two decades have marked a revolutionary period in biological sciences due to the development of gene splicing techniques. These methods have led to the directed engineering of organisms to develop new industrial products. The technology has been used to produce a wide variety of new pharmaceuticals and transgenic plants and animals. This technology is now also being applied to forest trees.

Biomass gasification for liquid fuel production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Najser, Jan, E-mail: jan.najser@vsb.cz, E-mail: vaclav.peer@vsb.cz; Peer, Václav, E-mail: jan.najser@vsb.cz, E-mail: vaclav.peer@vsb.cz; Vantuch, Martin

2014-08-06

In our old fix-bed autothermal gasifier we tested wood chips and wood pellets. We make experiments for Czech company producing agro pellets - pellets made from agricultural waste and fastrenewable natural resources. We tested pellets from wheat and rice straw and hay. These materials can be very perspective, because they dońt compete with food production, they were formed in sufficient quantity and in the place of their treatment. New installation is composed of allothermal biomass fixed bed gasifier with conditioning and using produced syngas for Fischer - Tropsch synthesis. As a gasifying agent will be used steam. Gas purification willmore » have two parts - separation of dust particles using a hot filter and dolomite reactor for decomposition of tars. In next steps, gas will be cooled, compressed and removed of sulphur and chlorine compounds and carbon dioxide. This syngas will be used for liquid fuel synthesis.« less

Biomass gasification for liquid fuel production

NASA Astrophysics Data System (ADS)

Najser, Jan; Peer, Václav; Vantuch, Martin

2014-08-01

In our old fix-bed autothermal gasifier we tested wood chips and wood pellets. We make experiments for Czech company producing agro pellets - pellets made from agricultural waste and fastrenewable natural resources. We tested pellets from wheat and rice straw and hay. These materials can be very perspective, because they dońt compete with food production, they were formed in sufficient quantity and in the place of their treatment. New installation is composed of allothermal biomass fixed bed gasifier with conditioning and using produced syngas for Fischer - Tropsch synthesis. As a gasifying agent will be used steam. Gas purification will have two parts - separation of dust particles using a hot filter and dolomite reactor for decomposition of tars. In next steps, gas will be cooled, compressed and removed of sulphur and chlorine compounds and carbon dioxide. This syngas will be used for liquid fuel synthesis.

Interior view, looking up toward project west at the heavy ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view, looking up toward project west at the heavy timber joists and center beam supporting the wood water tank. Note the iron compression bands around the perimeter of the tank. Note also the iron (steel?) water fill pipe for the tank, bent to fit between the joists and the tank wall. - East Broad Top Railroad & Company, Water Tank at Coles Station, East Broad Top Railroad & Company (at Milepost 24.3), 0.5 miles east of Coles Valley Road, Saltillo, Huntingdon County, PA

Fossil wood from the upper Miocene Mpesida Beds at Cheparain (Baringo District, Kenya): Botanical affinities and palaeoenvironmental implications

NASA Astrophysics Data System (ADS)

De Franceschi, Dario; Bamford, Marion; Pickford, Martin; Senut, Brigitte

2016-03-01

Seven wood samples from a petrified forest, in situ in ash flow deposits at Cheparain in the Tugen Hills (Kenya) in the Mpesida Beds, were discovered and studied. The age of the Mpesida Formation is estimated to be about 6.3 Ma on the basis of radio-isotope age determinations on the volcanic deposits, which overlie and underlie the sedimentary levels. The wood samples are mineralized with obvious sectors of differential mineralization, and different degrees of silica impregnation. All samples show heteroxylous structures corresponding to angiosperm dicotyledon trees. One sample consists in a half cylinder showing a well preserved mineralized structure of heteroxylous wood and probably corresponds to a fragment of root. This wood, with solitary (or in radial group) vessels, heterocellular multiseriate rays, paratracheal parenchyma in wide bands, and partly storied fusiform cells, clearly shows affinities with the genus Erythrina (Fabaceae). A slightly compressed branch, partly disturbed by injuries and highly mineralized shows solitary (or in short radial group) vessels, the rays uni-(bi) seriate are heterocellular, and the apotracheal parenchyma is in thin tangential bands. The closest affinities are with the genus Spirostachys (Euphorbiaceae). The other structures are poorly preserved (highly mineralized) and precise botanical affinities cannot be accessed. But the growth rings are distinct or diversely marked and the samples show semi-ring porous structures. They exhibit two different patterns. The growth rings reveal the presence of seasonal climate, and numerous injuries, a disturbance of the vegetation by animals and/or strong climatic events. Erythrina and Spirostachys are present in the extant vegetation of the Tana River Valley, in Kenya, which could represent a modern analogue for the vegetation of the Mpesida Beds prior to the major uplift of the Tugen Hills at the end of the Miocene.

Non-destructive testing techniques for the forensic engineering investigation of reinforced concrete buildings.

PubMed

Hobbs, Brian; Tchoketch Kebir, Mohamed

2007-04-11

This study describes in detail the results of a laboratory investigation where the compressive strength of 150mm side-length cubes was evaluated. Non-destructive testing (NDT) was carried out using ultrasonic pulse velocity (UPV) and impact rebound hammer (IRH) techniques to establish a correlation with the compressive strengths of compression tests. To adapt the Schmidt hammer apparatus and the ultrasonic pulse velocity tester to the type of concrete used in Algeria, concrete mix proportions that are recommended by the Algerian code were chosen. The resulting correlation curve for each test is obtained by changing the level of compaction, water/cement ratio and concrete age of specimens. Unlike other works, the research highlights the significant effect of formwork material on surface hardness of concrete where two different mould materials for specimens were used (plastic and wood). A combined method for the above two tests, reveals an improvement in the strength estimation of concrete. The latter shows more improvement by including the concrete density. The resulting calibration curves for strength estimation were compared with others from previous published literature.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blakely, R. J.; Sherrod, B. L.; Weaver, C. S.

Magnetic anomalies provide insights into the tectonic implications of a swarm of ~1500 shallow (~1 km deep) earthquakes that occurred in 2009 on the Hanford site, Washington. Epicenters were concentrated in a 2 km 2 area near Wooded Island in the Columbia River. The largest earthquake (M 3.0) had first motions consistent with slip on a northwest-striking reverse fault. The swarm was accompanied by 35 mm of vertical surface deformation, seen in satellite interferometry (InSAR), interpreted to be caused by ~50 mm of slip on a northwest-striking reverse fault and associated bedding-plane fault in the underlying Columbia River Basalt Groupmore » (CRBG). A magnetic anomaly over exposed CRBG at Yakima Ridge 40 km northwest of Wooded Island extends southeastward beyond the ridge to the Columbia River, suggesting that the Yakima Ridge anticline and its associated thrust fault extend southeastward in the subsurface. In map view, the concealed anticline passes through the earthquake swarm and lies parallel to reverse faults determined from first motions and InSAR data. A forward model of the magnetic anomaly near Wooded Island is consistent with uplift of concealed CRBG, with the top surface <200 m below the surface. The earthquake swarm and the thrust and bedding-plane faults modeled from interferometry all fall within the northeastern limb of the faulted anticline. Finally, although fluids may be responsible for triggering the Wooded Island earthquake swarm, the seismic and aseismic deformation are consistent with regional-scale tectonic compression across the concealed Yakima Ridge anticline.« less

A new shock wave assisted sandalwood oil extraction technique

NASA Astrophysics Data System (ADS)

Arunkumar, A. N.; Srinivasa, Y. B.; Ravikumar, G.; Shankaranarayana, K. H.; Rao, K. S.; Jagadeesh, G.

A new shock wave assisted oil extraction technique from sandalwood has been developed in the Shock Waves Lab, IISc, Bangalore. The fragrant oil extracted from sandalwood finds variety of applications in medicine and perfumery industries. In the present method sandal wood specimens (2.5mm diameter and 25mm in length)are subjected to shock wave loading (over pressure 15 bar)in a constant area shock tube, before extracting the sandal oil using non-destructive oil extraction technique. The results from the study indicates that both the rate of extraction as well as the quantity of oil obtained from sandal wood samples exposed to shock waves are higher (15-40 percent) compared to non-destructive oil extraction technique. The compressive squeezing of the interior oil pockets in the sandalwood specimen due to shock wave loading appears to be the main reason for enhancement in the oil extraction rate. This is confirmed by the presence of warty structures in the cross-section and micro-fissures in the radial direction of the wood samples exposed to shock waves in the scanning electron microscopic investigation. In addition the gas chromatographic studies do not show any change in the q uality of sandal oil extracted from samples exposed to shock waves.

Nuisance or Not? Part 2 "Wood" New Additives Make a Difference?

NASA Astrophysics Data System (ADS)

Vilardi, J. R.

2017-12-01

Nuisance or Not? Part 2"Wood" New Additives Make a Difference? Julian Vilardi Wetumpka Middle School, Wetumpka, USA Last year fuel briquettes were created out of nuisance organisms. Several samples had results better or comparable to the controls. This project is a revision/ extension. Purpose: Find process and formula for a long lasting environmentally friendly biofuel that produces high energy with low byproducts and low cost. Hypotheses: If wisteria is processed to make a biofuel that contains 90% wisteria leaves and vines and 10% pine cones, then a high energy, low byproduct, biofuel will be created. Procedure: Collect, dry and chop material, compress mass, burn test, repeat for every organism. Kudzu was combined in a 70 % kudzu: 30 % wood additive with used cooking oil and pressed into logs. Logs were massed, burned and temperature was recorded and compared to controls. Results: Kudzu had the longest flame but produced smoke. Kudzu logs with recycled cooking oil had less smoke and burned for an hour plus. Conclusions: Wisteria did not compact or have great flammability. Pine cones did not flame well either. This hypothesis was unsupported. All kudzu samples when compacted and combined with any additive were the best biofuel. Kudzu logs with the mixture of wood additives burned the longest and was one of the hottest. The gas chromatograph/emissions tests showed the organic byproducts produced on burning the kudzu logs were less than the accepted range for air quality. These supported the hypothesis and met the purpose of this project. A low cost, environmentally friendly, efficient fuel source was created!

Orthotropic creep in polyethylene glycol impregnated archaeological oak from the Vasa ship - Results of creep experiments in a museum-like climate

NASA Astrophysics Data System (ADS)

Vorobyev, Alexey; van Dijk, Nico P.; Kristofer Gamstedt, E.

2018-02-01

Creep in archaeological oak samples and planks from the Vasa ship impregnated with polyethylene glycol (PEG) has been studied in museum-like climate. Creep studies of duration up to three years have been performed in nearly constant relative humidity and temperature of the controlled museum climate. Cubic samples were subjected to compressive creep tests in all orthotropic directions. Additionally, the creep behaviour of planks with and without PEG and of recent oak was tested in four-point bending. The experimental results have been summarised and also compared with reference results from recent oak wood. The effect of variable ambient conditions on creep and mass changes is discussed. The experimental results of creep in the longitudinal direction showed deformations even for the low stresses. There is relatively much more scatter in creep behaviour, and not all samples showed linear viscoelastic response. The creep in radial and tangential directions of the cubes and the plank samples showed a strong dependency on the ambient conditions. Some samples showed expansion for decreasing moisture content, possibly caused by the thermal expansion of the PEG component. For the planks, increasing creep deformation was observed induced by changing ambient conditions. Such behaviour may be related to e.g. oscillations in ambient conditions and presence of PEG in the wood cell wall and cell lumen. The behaviour of PEG archaeological wood depends on the level of deterioration that occurred over centuries. However, although the findings presented here apply to this specific case, they provide a unique view on such wood.

Influence of reinforcement type on the mechanical behavior and fire response of hybrid composites and sandwich structures

NASA Astrophysics Data System (ADS)

Giancaspro, James William

Lightweight composites and structural sandwich panels are commonly used in marine and aerospace applications. Using carbon, glass, and a host of other high strength fiber types, a broad range of laminate composites and sandwich panels can be developed. Hybrid composites can be constructed by laminating multiple layers of varying fiber types while sandwich panels are manufactured by laminating rigid fiber facings onto a lightweight core. However, the lack of fire resistance of the polymers used for the fabrication remains a very important problem. The research presented in this dissertation deals with an inorganic matrix (Geopolymer) that can be used to manufacture laminate composites and sandwich panels that are resistant up to 1000°C. This dissertation deals with the influence of fiber type on the mechanical behavior and the fire response of hybrid composites and sandwich structures manufactured using this resin. The results are categorized into the following distinct studies. (i) High strength carbon fibers were combined with low cost E-glass fibers to obtain hybrid laminate composites that are both economical and strong. The E-glass fabrics were used as a core while the carbon fibers were placed on the tension face and on both tension and compression faces. (ii) Structural sandwich beams were developed by laminating various types of reinforcement onto the tension and compression faces of balsa wood cores. The flexural behavior of the beams was then analyzed and compared to beams reinforced with organic composite. The effect of core density was evaluated using oak beams reinforced with inorganic composite. (iii) To measure the fire response, balsa wood sandwich panels were manufactured using a thin layer of a fire-resistant paste to serve for fire protection. Seventeen sandwich panels were fabricated and tested to measure the heat release rates and smoke-generating characteristics. The results indicate that Geopolymer can be effectively used to fabricate both high strength composite plates and sandwich panels. A 2 mm thick coating of fireproofing on balsa wood is sufficient to satisfy FAA fire requirements.

Design Criteria for Deflection Capacity of conventionally Reinforced Concrete Slabs. Phase I. State-of-the-Art Report.

DTIC Science & Technology

1980-10-01

Previous Investigations 9 3.2 Ockleston’s Work 9 3.3 Wood’s Work 11 3.3.1 Experimental Investigation 11 3.3.2 Analytical investigation 13 3.3.3 Load...Deflection Relationship 16 3.4 Sawczuck’s Work 17 3.5 Park’s Work on Compressive Membrane Action 19 3.5.1 Experimental Investigation 19 3.5.2 Analysis of...DEFLECTION CAPACITY 104 8.1 Idealized Load-Deflection Behavior of a Restrained Strip 104 8.2 A Comparison with Experimental Results 110 9. DEVELOPMENT OF

Method and apparatus for de-watering biomass materials in a compression drying process

DOEpatents

Haygreen, John G.

1986-01-01

A method and apparatus for more effectively squeezing moisture from wood chips and/or other "green" biomass materials. A press comprising a generally closed chamber having a laterally movable base at the lower end thereof, and a piston or ram conforming in shape to the cross-section of the chamber is adapted to periodically receive a charge of biomass material to be dehydrated. The ram is forced against the biomass material with suffcient force to compress the biomass and to crush the matrix in which moisture is contained within the material with the face of the ram being configured to cause a preferential flow of moisture from the center of the mass outwardly to the grooved walls of the chamber. Thus, the moisture is effectively squeezed from the biomass and flows through the grooves formed in the walls of the chamber to a collecting receptacle and is not drawn back into the mass by capillary action when the force is removed from the ram.

Extraction of features from ultrasound acoustic emissions: a tool to assess the hydraulic vulnerability of Norway spruce trunkwood?

PubMed Central

Rosner, Sabine; Klein, Andrea; Wimmer, Rupert; Karlsson, Bo

2011-01-01

Summary • The aim of this study was to assess the hydraulic vulnerability of Norway spruce (Picea abies) trunkwood by extraction of selected features of acoustic emissions (AEs) detected during dehydration of standard size samples. • The hydraulic method was used as the reference method to assess the hydraulic vulnerability of trunkwood of different cambial ages. Vulnerability curves were constructed by plotting the percentage loss of conductivity vs an overpressure of compressed air. • Differences in hydraulic vulnerability were very pronounced between juvenile and mature wood samples; therefore, useful AE features, such as peak amplitude, duration and relative energy, could be filtered out. The AE rates of signals clustered by amplitude and duration ranges and the AE energies differed greatly between juvenile and mature wood at identical relative water losses. • Vulnerability curves could be constructed by relating the cumulated amount of relative AE energy to the relative loss of water and to xylem tension. AE testing in combination with feature extraction offers a readily automated and easy to use alternative to the hydraulic method. PMID:16771986

PpNAC1, a main regulator of phenylalanine biosynthesis and utilization in maritime pine.

PubMed

Pascual, María Belén; Llebrés, María-Teresa; Craven-Bartle, Blanca; Cañas, Rafael A; Cánovas, Francisco M; Ávila, Concepción

2018-05-01

The transcriptional regulation of phenylalanine metabolism is particularly important in conifers, long-lived species that use large amounts of carbon in wood. Here, we show that the Pinus pinaster transcription factor, PpNAC1, is a main regulator of phenylalanine biosynthesis and utilization. A phylogenetic analysis classified PpNAC1 in the NST proteins group and was selected for functional characterization. PpNAC1 is predominantly expressed in the secondary xylem and compression wood of adult trees. Silencing of PpNAC1 in P. pinaster results in the alteration of stem vascular radial patterning and the down-regulation of several genes associated with cell wall biogenesis and secondary metabolism. Furthermore, transactivation and EMSA analyses showed that PpNAC1 is able to activate its own expression and PpMyb4 promoter, while PpMyb4 is able to activate PpMyb8, a transcriptional regulator of phenylalanine and lignin biosynthesis in maritime pine. Together, these results suggest that PpNAC1 is a functional ortholog of the ArabidopsisSND1 and NST1 genes and support the idea that key regulators governing secondary cell wall formation could be conserved between gymnosperms and angiosperms. Understanding the molecular switches controlling wood formation is of paramount importance for fundamental tree biology and paves the way for applications in conifer biotechnology. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Injection of Compressed Diced Cartilage in the Correction of Secondary and Primary Rhinoplasty: A New Technique with 12 Years' Experience.

PubMed

Erol, O Onur

2017-11-01

There are instances where small or large pockets are filled with diced cartilage in the nose, without use of wrapping materials. For this purpose, 1-cc commercial syringes were used. The obtained results were partial and incomplete. For better and improved results, the author designed new syringes, with two different sizes, which compress the diced cartilage for injection. The author presents his experience accrued over the past 12 years with 2366 primary, 749 secondary, 67 cleft lip and nose, and a total of 3182 rhinoplasties, using his new syringe design, which compresses diced cartilage and injects the diced cartilages as a conglutinate mass, simulating carved costal cartilage, but a malleable one. In 3125 patients, the take of cartilage graft was complete (98.2 percent) and a smooth surface was obtained, giving them a natural appearance. In 21 patients (0.65 percent), there was partial resorption of cartilage. Correction was performed with touch-up surgery by reinjection of a small amount of diced cartilage. In 36 patients (1.13 percent), there was overcorrection that, 1 year later, was treated by simple rasping. Compared with diced cartilage wrapped with Surgicel or fascia, the amount of injected cartilage graft is predictable because it consists purely of cartilage. The injected diced cartilage, because it is compressed and becomes a conglutinated mass, resembles a wood chip and simulates carved cartilage. It is superior to carved cartilage in that it is moldable, time saving, and gives a good result with no late show or warping. The injection takes only a few minutes.

Thermal conductivity of cement stabilized earth bricks reinforced with date palm fiber

NASA Astrophysics Data System (ADS)

Berrehail, Tahar; Zemmouri, Noureddine; Agoudjil, Boudjemaa

2018-05-01

Recently, some cheap materials are available and adaptable to climate seem to meet current requirements. This paper investigates the thermal and mechanical properties of cement stabilized earth bricks(CSEB) reinforced with date palm fibers (DPF). The main goal is to develop and expand the field of use of these materials in the construction sector, and investigate the possibility of new bio composite as renewable, insulating building material with low cost, made of earth and reinforced with palm wood waste. In this study, a particular interest is brought to the thermal and mechanical characteristics, which constitute a decisive character for the choice of a building material. A series of earthen samples stabilized at 5% and reinforced with DPF of various fiber weight fractions, (5%, 10%), were manufactured and compacted applying two levels compacting, (5MPa and 10MPa). Compressive strength and thermal conductivity were experimentally studied; heating capacity and diffusivity were indirectly calculated. It was found that the fibrous reinforcement proved thermal conductivity and compressive strength. it also enhanced thermal performances. Thus, the results found allow us to investigate hygrothermal behaviour and its impact on occupants comfort.

Conifer R2R3-MYB transcription factors: sequence analyses and gene expression in wood-forming tissues of white spruce (Picea glauca)

PubMed Central

Bedon, Frank; Grima-Pettenati, Jacqueline; Mackay, John

2007-01-01

Background Several members of the R2R3-MYB family of transcription factors act as regulators of lignin and phenylpropanoid metabolism during wood formation in angiosperm and gymnosperm plants. The angiosperm Arabidopsis has over one hundred R2R3-MYBs genes; however, only a few members of this family have been discovered in gymnosperms. Results We isolated and characterised full-length cDNAs encoding R2R3-MYB genes from the gymnosperms white spruce, Picea glauca (13 sequences), and loblolly pine, Pinus taeda L. (five sequences). Sequence similarities and phylogenetic analyses placed the spruce and pine sequences in diverse subgroups of the large R2R3-MYB family, although several of the sequences clustered closely together. We searched the highly variable C-terminal region of diverse plant MYBs for conserved amino acid sequences and identified 20 motifs in the spruce MYBs, nine of which have not previously been reported and three of which are specific to conifers. The number and length of the introns in spruce MYB genes varied significantly, but their positions were well conserved relative to angiosperm MYB genes. Quantitative RTPCR of MYB genes transcript abundance in root and stem tissues revealed diverse expression patterns; three MYB genes were preferentially expressed in secondary xylem, whereas others were preferentially expressed in phloem or were ubiquitous. The MYB genes expressed in xylem, and three others, were up-regulated in the compression wood of leaning trees within 76 hours of induction. Conclusion Our survey of 18 conifer R2R3-MYB genes clearly showed a gene family structure similar to that of Arabidopsis. Three of the sequences are likely to play a role in lignin metabolism and/or wood formation in gymnosperm trees, including a close homolog of the loblolly pine PtMYB4, shown to regulate lignin biosynthesis in transgenic tobacco. PMID:17397551

Tradeoffs between hydraulic and mechanical stress responses of mature Norway spruce trunk wood.

PubMed

Rosner, Sabine; Klein, Andrea; Müller, Ulrich; Karlsson, Bo

2008-08-01

We tested the effects of growth characteristics and basic density on hydraulic and mechanical properties of mature Norway spruce (Picea abies (L.) Karst.) wood from six 24-year-old clones, grown on two sites in southern Sweden differing in water availability. Hydraulic parameters assessed were specific hydraulic conductivity at full saturation (ks100) and vulnerability to cavitation (Psi50), mechanical parameters included bending strength (sigma b), modulus of elasticity (MOE), compression strength (sigma a) and Young's modulus (E). Basic density, diameter at breast height, tree height, and hydraulic and mechanical parameters varied considerably among clones. Clonal means of hydraulic and mechanical properties were strongly related to basic density and to growth parameters across sites, especially to diameter at breast height. Compared with stem wood of slower growing clones, stem wood of rapidly growing clones had significantly lower basic density, lower sigma b, MOE, sigma a and E, was more vulnerable to cavitation, but had higher ks100. Basic density was negatively correlated to Psi50 and ks100. We therefore found a tradeoff between Psi50 and ks100. Clones with high basic density had significantly lower hydraulic vulnerability, but also lower hydraulic conductivity at full saturation and thus less rapid growth than clones with low basic density. This tradeoff involved a negative relationship between Psi50 and sigma b as well as MOE, and between ks100 and sigma b, MOE and sigma a. Basic density and Psi50 showed no site-specific differences, but tree height, diameter at breast height, ks100 and mechanical strength and stiffness were significantly lower at the drier site. Basic density had no influence on the site-dependent differences in hydraulic and mechanical properties, but was strongly negatively related to diameter at breast height. Selecting for growth may thus lead not only to a reduction in mechanical strength and stiffness but also to a reduction in hydraulic safety.

Thermal Pretreatment of Wood for Co-gasification/co-firing of Biomass and Coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ping; Howard, Bret; Hedges, Sheila

2013-10-29

Utilization of biomass as a co-feed in coal and biomass co-firing and co-gasification requires size reduction of the biomass. Reducing biomass to below 0.2 mm without pretreatment is difficult and costly because biomass is fibrous and compressible. Torrefaction is a promising thermal pretreatment process and has the advantages of increasing energy density, improving grindability, producing fuels with more homogenous compositions and hydrophobic behavior. Temperature is the most important factor for the torrefaction process. Biomass grindability is related to cell wall structure, thickness and composition. Thermal treatment such as torrefaction can cause chemical changes that significantly affect the strength of biomass.more » The objectives of this study are to understand the mechanism by which torrefaction improves the grindability of biomass and discuss suitable temperatures for thermal pretreatment for co-gasification/co-firing of biomass and coal. Wild cherry wood was selected as the model for this study. Samples were prepared by sawing a single tangential section from the heartwood and cutting it into eleven pieces. The samples were consecutively heated at 220, 260, 300, 350, 450 and 550⁰C for 0.5 hr under flowing nitrogen in a tube furnace. Untreated and treated samples were characterized for physical properties (color, dimensions and weight), microstructural changes by SEM, and cell wall composition changes and thermal behaviors by TGA and DSC. The morphology of the wood remained intact through the treatment range but the cell walls were thinner. Thermal treatments were observed to decompose the cell wall components. Hemicellulose decomposed over the range of ~200 to 300⁰C and resulted in weakening of the cell walls and subsequently improved grindability. Furthermore, wood samples treated above 300⁰C lost more than 39% in mass. Therefore, thermal pretreatment above the hemicelluloses decomposition temperature but below 300⁰C is probably sufficient to improve grindability and retain energy value.« less

How different are the results acquired from mathematical and subjective methods in dendrogeomorphology? Insights from landslide movements

NASA Astrophysics Data System (ADS)

Šilhán, Karel

2016-01-01

Knowledge of past landslide activity is crucial for understanding landslide behaviour and for modelling potential future landslide occurrence. Dendrogeomorphic approaches represent the most precise methods of landslide dating (where trees annually create tree-rings in the timescale of up to several hundred years). Despite the advantages of these methods, many open questions remain. One of the less researched uncertainties, and the focus of this study, is the impact of two common methods of geomorphic signal extraction on the spatial and temporal results of landslide reconstruction. In total, 93 Norway spruce (Picea abies (L.) Karst.) trees were sampled at one landslide location dominated by block-type movements in the forefield of the Orlické hory Mts., Bohemian Massif. Landslide signals were examined by the classical subjective method based on reaction (compression) wood analysis and by a numerical method based on eccentric growth analysis. The chronology of landslide movements obtained by the mathematical method resulted in twice the number of events detected compared to the subjective method. This finding indicates that eccentric growth is a more accurate indicator for landslide movements than the classical analysis of reaction wood. The reconstructed spatial activity of landslide movements shows a similar distribution of recurrence intervals (Ri) for both methods. The differences (maximally 30% of the total Ri ranges) in results obtained by both methods may be caused by differences in the ability of trees to react to tilting of their stems by a specific growth response (reaction wood formation or eccentric growth). Finally, the ability of trees to record tilting events (by both growth responses) in their tree-ring series was analysed for different decades of tree life. The highest sensitivity to external tilting events occurred at tree ages from 70 to 80 years for reaction wood formation and from 80 to 90 years for eccentric growth response. This means that the ability of P. abies to record geomorphic signals varies with not only eccentric growth responses but also with age.

Femtosecond laser machining for characterization of local mechanical properties of biomaterials: a case study on wood

PubMed Central

Jakob, Severin; Pfeifenberger, Manuel J.; Hohenwarter, Anton; Pippan, Reinhard

2017-01-01

Abstract The standard preparation technique for micro-sized samples is focused ion beam milling, most frequently using Ga+ ions. The main drawbacks are the required processing time and the possibility and risks of ion implantation. In contrast, ultrashort pulsed laser ablation can process any type of material with ideally negligible damage to the surrounding volume and provides 4 to 6 orders of magnitude higher ablation rates than the ion beam technique. In this work, a femtosecond laser was used to prepare wood samples from spruce for mechanical testing at the micrometre level. After optimization of the different laser parameters, tensile and compressive specimens were produced from microtomed radial-tangential and longitudinal-tangential sections. Additionally, laser-processed samples were exposed to an electron beam prior to testing to study possible beam damage. The specimens originating from these different preparation conditions were mechanically tested. Advantages and limitations of the femtosecond laser preparation technique and the deformation and fracture behaviour of the samples are discussed. The results prove that femtosecond laser processing is a fast and precise preparation technique, which enables the fabrication of pristine biological samples with dimensions at the microscale. PMID:28970867

Femtosecond laser machining for characterization of local mechanical properties of biomaterials: a case study on wood

NASA Astrophysics Data System (ADS)

Jakob, Severin; Pfeifenberger, Manuel J.; Hohenwarter, Anton; Pippan, Reinhard

2017-12-01

The standard preparation technique for micro-sized samples is focused ion beam milling, most frequently using Ga+ ions. The main drawbacks are the required processing time and the possibility and risks of ion implantation. In contrast, ultrashort pulsed laser ablation can process any type of material with ideally negligible damage to the surrounding volume and provides 4 to 6 orders of magnitude higher ablation rates than the ion beam technique. In this work, a femtosecond laser was used to prepare wood samples from spruce for mechanical testing at the micrometre level. After optimization of the different laser parameters, tensile and compressive specimens were produced from microtomed radial-tangential and longitudinal-tangential sections. Additionally, laser-processed samples were exposed to an electron beam prior to testing to study possible beam damage. The specimens originating from these different preparation conditions were mechanically tested. Advantages and limitations of the femtosecond laser preparation technique and the deformation and fracture behaviour of the samples are discussed. The results prove that femtosecond laser processing is a fast and precise preparation technique, which enables the fabrication of pristine biological samples with dimensions at the microscale.

Suppression of 4-Coumarate-CoA Ligase in the Coniferous Gymnosperm Pinus radiata1[W

PubMed Central

Wagner, Armin; Donaldson, Lloyd; Kim, Hoon; Phillips, Lorelle; Flint, Heather; Steward, Diane; Torr, Kirk; Koch, Gerald; Schmitt, Uwe; Ralph, John

2009-01-01

Severe suppression of 4-coumarate-coenzyme A ligase (4CL) in the coniferous gymnosperm Pinus radiata substantially affected plant phenotype and resulted in dwarfed plants with a “bonsai tree-like” appearance. Microscopic analyses of stem sections from 2-year-old plants revealed substantial morphological changes in both wood and bark tissues. This included the formation of weakly lignified tracheids that displayed signs of collapse and the development of circumferential bands of axial parenchyma. Acetyl bromide-soluble lignin assays and proton nuclear magnetic resonance studies revealed lignin reductions of 36% to 50% in the most severely affected transgenic plants. Two-dimensional nuclear magnetic resonance and pyrolysis-gas chromatography-mass spectrometry studies indicated that lignin reductions were mainly due to depletion of guaiacyl but not p-hydroxyphenyl lignin. 4CL silencing also caused modifications in the lignin interunit linkage distribution, including elevated β-aryl ether (β-O-4 unit) and spirodienone (β-1) levels, accompanied by lower phenylcoumaran (β-5), resinol (β-β), and dibenzodioxocin (5-5/β-O-4) levels. A sharp depletion in the level of saturated (dihydroconiferyl alcohol) end groups was also observed. Severe suppression of 4CL also affected carbohydrate metabolism. Most obvious was an up to approximately 2-fold increase in galactose content in wood from transgenic plants due to increased compression wood formation. The molecular, anatomical, and analytical data verified that the isolated 4CL clone is associated with lignin biosynthesis and illustrated that 4CL silencing leads to complex, often surprising, physiological and morphological changes in P. radiata. PMID:18971431

The computational modeling of supercritical carbon dioxide flow in solid wood material

NASA Astrophysics Data System (ADS)

Gething, Brad Allen

The use of supercritical carbon dioxide (SC CO2) as a solvent to deliver chemicals to porous media has shown promise in various industries. Recently, efforts by the wood treating industry have been made to use SC CO 2 as a replacement to more traditional methods of chemical preservative delivery. Previous studies have shown that the SC CO2 pressure treatment process is capable of impregnating solid wood materials with chemical preservatives, but concentration gradients of preservative often develop during treatment. Widespread application of the treatment process is unlikely unless the treatment inconsistencies can be improved for greater overall treating homogeneity. The development of a computational flow model to accurately predict the internal pressure of CO2 during treatment is integral to a more consistent treatment process. While similar models that attempt to describe the flow process have been proposed by Ward (1989) and Sahle-Demessie (1994), neither have been evaluated for accuracy. The present study was an evaluation of those models. More specifically, the present study evaluated the performance of a computational flow model, which was based on the viscous flow of compressible CO2 as a single phase through a porous medium at the macroscopic scale. Flow model performance was evaluated through comparisons between predicted pressures that corresponded to internal pressure development measured with inserted sensor probes during treatment of specimens. Pressure measurements were applied through a technique developed by Schneider (2000), which utilizes epoxy-sealed stainless steel tubes that are inserted into the wood as pressure probes. Two different wood species were investigated as treating specimens, Douglas-fir and shortleaf pine. Evaluations of the computational flow model revealed that it is sensitive to input parameters that relate to both processing conditions and material properties, particularly treating temperature and wood permeability, respectively. This sensitivity requires that the input parameters, principally permeability, be relatively accurate to evaluate the appropriateness of the phenomenological relationships of the computational flow model. Providing this stipulation, it was observed that below the region of transition from CO2 gas to supercritical fluid, the computational flow model has the potential to predict flow accurately. However, above the transition region, the model does not fully account for the physics of the flow process, resulting in prediction inaccuracy. One potential cause for the loss of prediction accuracy in the supercritical region was attributed to a dynamic change in permeability that is likely caused by an interaction between the flowing SC CO2 and the wood material. Furthermore, a hysteresis was observed between the pressurization and depressurization stages of treatment, which cannot be explained by the current flow model. If greater accuracy in the computational flow model is desired, a more complex approach to the model is necessary, which would include non-constant input parameters of temperature and permeability. Furthermore, the implications of a multi-scale methodology for the flow model were explored from a qualitative standpoint.

The ultimate state of polymeric materials and laminated and fibrous composites under asymmetric high-cycle loading

NASA Astrophysics Data System (ADS)

Golub, V. P.; Pogrebniak, A. D.; Kochetkova, E. S.

2008-01-01

The prediction of the high-cycle fatigue strength of polymeric and composite materials in asymmetric loading is considered. The problem is solved on the basis of a nonlinear model of ultimate state allowing us to describe all typical forms of the diagrams of ultimate stresses. The material constants of the model are determined from the results of fatigue tests in symmetric reversed cycling, in a single fatigue test with the minimum stress equal to zero, and in a short-term strength test. The fatigue strength characteristics of some polymers, glass-fiber laminates, glass-fiber-reinforced plastics, organic-fiber-reinforced plastics, and wood laminates in asymmetric tension-compression, bending, and torsion have been calculated and approved experimentally.

Cellulose microfibril orientation of Picea abies and its variability at the micron-level determined by Raman imaging.

PubMed

Gierlinger, Notburga; Luss, Saskia; König, Christian; Konnerth, Johannes; Eder, Michaela; Fratzl, Peter

2010-01-01

The functional characteristics of plant cell walls depend on the composition of the cell wall polymers, as well as on their highly ordered architecture at scales from a few nanometres to several microns. Raman spectra of wood acquired with linear polarized laser light include information about polymer composition as well as the alignment of cellulose microfibrils with respect to the fibre axis (microfibril angle). By changing the laser polarization direction in 3 degrees steps, the dependency between cellulose and laser orientation direction was investigated. Orientation-dependent changes of band height ratios and spectra were described by quadratic linear regression and partial least square regressions, respectively. Using the models and regressions with high coefficients of determination (R(2) > 0.99) microfibril orientation was predicted in the S1 and S2 layers distinguished by the Raman imaging approach in cross-sections of spruce normal, opposite, and compression wood. The determined microfibril angle (MFA) in the different S2 layers ranged from 0 degrees to 49.9 degrees and was in coincidence with X-ray diffraction determination. With the prerequisite of geometric sample and laser alignment, exact MFA prediction can complete the picture of the chemical cell wall design gained by the Raman imaging approach at the micron level in all plant tissues.

Cleansing technique using high-velocity steam-air micromist jet spray.

PubMed

Fukuda, Koichi; Ishihara, Masayuki; Murakami, Kaoru; Nakamura, Shingo; Sato, Yoko; Kuwabara, Masahiro; Fujita, Masanori; Kiyosawa, Tomoharu; Yokoe, Hidetaka

2017-10-01

Application of a high-velocity steam-air micromist jet spray (HVS-AMJS; micromist average diameter: 2.4 μm) for cleansing the skin is proposed. Low-pressure steam is mixed with compressed air (pH 6.5) in a nozzle, and then sprayed at a pressure of ≦0.25 MPa and a velocity of ≧0.34 m/s on the skin or surface of material located approximately 5-10 cm from the nozzle. The temperature on the sprayed surface and water flow rate could be controlled between 42 °C and 46 °C and at approximately 50 mL/min, respectively. Compared with ultrasonic cleansing with tap water and rubbing with only tap water, the HVS-AMJS successfully removed fluorescent lotion covering pieces of wood and significantly reduced both the number of coliforms and the total viable counts on pieces of wood and gauze. Furthermore, the HVS-AMJS effectively removed oily ink from the skin of hairless rats, and temporarily elevated the skin temperature and blood flow, indicating massage effects. The striking characteristics of this cleansing technique using HVS-AMJS are not only its ability to remove microbes and residue without using any chemicals or detergents but also its massage effects.

Characterization, reproduction and optimization of traditional adobe bricks

NASA Astrophysics Data System (ADS)

Ioannou, Ioannis; Eftychiou, Marina; Costi de Castrillo, Maria; Illampas, Rogiros

2013-04-01

Adobe bricks were first introduced 10-12,000 years ago. Extensive use of the material throughout the centuries has led to strong local traditions of building with earth and has established adobe masonry as an important feature of the international architectural heritage. Today, despite no longer being a prevalent building material, adobes are still in use, since a number of earthen structures survive worldwide. Furthermore, the simplicity, low cost and almost negligible embodied energy associated with the production of adobes, as well as their good thermal and acoustic properties, render them an attractive option for use in contemporary sustainable construction. Therefore, several ongoing research projects internationally investigate the physicochemical and mechanical properties of traditional adobe bricks and the design/production of optimized adobes, with improved characteristics, for use in contemporary architecture. Here, we present ongoing research on adobe bricks carried out in the framework of the project E& IXEIPH EI / POION/0609/41, which is co-funded by the European Regional Development Fund and the Republic of Cyprus, through the Cyprus Research Promotion Foundation. Our work focuses on the characterization of traditional adobes, their reproduction and optimization in the laboratory to produce materials with improved physicomechanical properties. Results up-to-date show that traditional adobes are mostly composed of random quantities of silt and clay. Calcite is also predominant in relevant X-ray diffraction analyses. The average capillary water absorption coefficient (measured against a saturated sponge surface) of samples collected from market suppliers rarely exceeds 1 mm/min1 -2, while their thermal conductivity is around 0.55 W/mK. The response of traditional adobes to compression is characterized by intense deformability. The average compressive strength recorded depends on the form of test specimen (cube, cylinder, prism). Samples with aspect ratio 1:1 produce results ranging from 1-2 MPa, whereas prisms with height-to-width ratios < 1 give values from 2.5-9 MPa. Differences are noted among the properties of: (a) adobes produced by different manufactures; (b) adobes made by the same manufacturer but originating from different production batches and (c) specimens originating from the same brick. When subjected to three-point bending, the behaviour of adobes is influenced by the presence of discontinuities within their mass. Hence, flexural strength is rather variable and weakly correlated to compressive strength. This abnormal mechanical behaviour is attributed to the inherent inhomogeneity and natural randomness of adobes which is "enhanced" by the adoption of empirical non-industrialized production methods. Discrepancy in the outcomes of laboratory tests is further affected by the lack of standardized testing methods and formal failure criteria. Laboratory designed and produced adobes show improved mechanical properties and lower thermal conductivities. The addition of wood dust in the mixture, at quantities up to 60% by volume, seems particularly beneficial, as it raises the compressive strength of the material over 6 MPa, while at the same time it reduces its capillary water absorption coefficient to about 0.35 mm/min1 -2. The latter is further reduced by the use of commercially available water repellents in the mixture. Wood dust also reduces the thermal conductivity of adobes. Among the stabilizing additives used, gypsum proved to be the most beneficial. In general, simple modifications to the procedure followed during the laboratory production of adobes, such as in the filling of moulds, lead to higher density and compressive strength of the end-product.

46 CFR 148.325 - Wood chips; wood pellets; wood pulp pellets.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Wood chips; wood pellets; wood pulp pellets. 148.325... § 148.325 Wood chips; wood pellets; wood pulp pellets. (a) This part applies to wood chips and wood pulp... cargo hold. (b) No person may enter a cargo hold containing wood chips, wood pellets, or wood pulp...

46 CFR 148.325 - Wood chips; wood pellets; wood pulp pellets.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Wood chips; wood pellets; wood pulp pellets. 148.325... § 148.325 Wood chips; wood pellets; wood pulp pellets. (a) This part applies to wood chips and wood pulp... cargo hold. (b) No person may enter a cargo hold containing wood chips, wood pellets, or wood pulp...

46 CFR 148.325 - Wood chips; wood pellets; wood pulp pellets.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Wood chips; wood pellets; wood pulp pellets. 148.325... § 148.325 Wood chips; wood pellets; wood pulp pellets. (a) This part applies to wood chips and wood pulp... cargo hold. (b) No person may enter a cargo hold containing wood chips, wood pellets, or wood pulp...

46 CFR 148.325 - Wood chips; wood pellets; wood pulp pellets.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Wood chips; wood pellets; wood pulp pellets. 148.325... § 148.325 Wood chips; wood pellets; wood pulp pellets. (a) This part applies to wood chips and wood pulp... cargo hold. (b) No person may enter a cargo hold containing wood chips, wood pellets, or wood pulp...

Cellulose microfibril orientation of Picea abies and its variability at the micron-level determined by Raman imaging

PubMed Central

Gierlinger, Notburga; Luss, Saskia; König, Christian; Konnerth, Johannes; Eder, Michaela; Fratzl, Peter

2010-01-01

The functional characteristics of plant cell walls depend on the composition of the cell wall polymers, as well as on their highly ordered architecture at scales from a few nanometres to several microns. Raman spectra of wood acquired with linear polarized laser light include information about polymer composition as well as the alignment of cellulose microfibrils with respect to the fibre axis (microfibril angle). By changing the laser polarization direction in 3° steps, the dependency between cellulose and laser orientation direction was investigated. Orientation-dependent changes of band height ratios and spectra were described by quadratic linear regression and partial least square regressions, respectively. Using the models and regressions with high coefficients of determination (R2 > 0.99) microfibril orientation was predicted in the S1 and S2 layers distinguished by the Raman imaging approach in cross-sections of spruce normal, opposite, and compression wood. The determined microfibril angle (MFA) in the different S2 layers ranged from 0° to 49.9° and was in coincidence with X-ray diffraction determination. With the prerequisite of geometric sample and laser alignment, exact MFA prediction can complete the picture of the chemical cell wall design gained by the Raman imaging approach at the micron level in all plant tissues. PMID:20007198

Failure of structural elements made of polymer supported composite materials during the multiyear natural aging

NASA Astrophysics Data System (ADS)

Blinkov, Pavel; Ogorodov, Leonid; Grabovyy, Peter

2018-03-01

Modern high-rise construction introduces a number of limitations and tasks. In addition to durability, comfort and profitability, projects should take into account energy efficiency and environmental problems. Polymer building materials are used as substitutes for materials such as brick, concrete, metal, wood and glass, and in addition to traditional materials. Plastic materials are light, can be formed into complex shapes, durable and low, and also possess a wide range of properties. Plastic materials are available in various forms, colors and textures and require minimal or no color. They are resistant to heat transfer and diffusion of moisture and do not suffer from metal corrosion or microbial attack. Polymeric materials, including thermoplastics, thermoset materials and wood-polymer composites, have many structural and non-structural applications in the construction industry. They provide unique and innovative solutions at a low cost, and their use is likely to grow in the future. A number of polymer composite materials form complex material compositions, which are applied in the construction in order to analyze the processes of damage accumulation under the conditions of complex nonstationary loading modes, and to determine the life of structural elements considering the material aging. This paper present the results of tests on short-term compression loading with a deformation rate of v = 2 mm/min using composite samples of various shapes and sizes.

Implementation of recycled cellulosic fibres into cement based composites and testing their influence on resulting properties

NASA Astrophysics Data System (ADS)

Hospodarova, V.; Stevulova, N.; Vaclavik, V.; Dvorsky, T.

2017-10-01

Nowadays, the application of raw materials from renewable sources such as wood, plants and waste paper to building materials preparing has gained a significant interest in this research area. The aim of this paper is to investigate the impact of the selected plasticizer on properties of fibres composites made of cellulosic fibres coming from recycled waste paper and cement. Investigations were performed on specimens with 0.5 wt. % of fibre addition without and with plasticizer. A comparative study did not show positive influence of plasticizer on the density and thermal conductivity of 28 days hardened composite. The specimens after 1, 3 and 7 days of hardening with plasticizer exhibited the highest impact on compressive strength in comparison to composite without plasticizer but 28 days hardened specimens reached the same value of strength characteristic (41 MPa).

Modélisation de la viscoélasticité transverse du bois vert à l'aide d'une combinaison de deux éléments paraboliques

NASA Astrophysics Data System (ADS)

Bardet, Sandrine; Gril, Joseph

The rigidity in radial compression at different levels of temperature and strain rate have been measured on green Boco, with a drastic softening around 60 ∘ C attributed to the glassy transition of lignin. The representation of experimental results in an approximated complex diagram revealed a secondary viscoelastic process occurring at lower temperature. A multiparabolic model was used for the analysis. For convenience, each parabolic element was replaced by a generalised Maxwell model with a modified-Gaussian relaxation spectrum. This model fitted correctly the observed behaviour of wood in the time range of 0.05 to 50 sec and temperature between 10 to 90 ∘ C. To cite this article: S. Bardet, J. Gril, C. R. Mecanique 330 (2002) 549-556.

Significance of wood extractives for wood bonding.

PubMed

Roffael, Edmone

2016-02-01

Wood contains primary extractives, which are present in all woods, and secondary extractives, which are confined in certain wood species. Extractives in wood play a major role in wood-bonding processes, as they can contribute to or determine the bonding relevant properties of wood such as acidity and wettability. Therefore, extractives play an immanent role in bonding of wood chips and wood fibres with common synthetic adhesives such as urea-formaldehyde-resins (UF-resins) and phenol-formaldehyde-resins (PF-resins). Extractives of high acidity accelerate the curing of acid curing UF-resins and decelerate bonding with alkaline hardening PF-resins. Water-soluble extractives like free sugars are detrimental for bonding of wood with cement. Polyphenolic extractives (tannins) can be used as a binder in the wood-based industry. Additionally, extractives in wood can react with formaldehyde and reduce the formaldehyde emission of wood-based panels. Moreover, some wood extractives are volatile organic compounds (VOC) and insofar also relevant to the emission of VOC from wood and wood-based panels.

Wood : adhesives

Treesearch

A.H. Conner

2001-01-01

This chapter on wood adhesives includes: 1) Classification of wood adhesives 2) Thermosetting wood adhesives 3) Thermoplastic adhesives, 4) Wood adhesives based on natural sources 5) Nonconventional bonding of wood 6) Wood bonding.

Variation in wood nutrients along a tropical soil fertility gradient.

PubMed

Heineman, Katherine D; Turner, Benjamin L; Dalling, James W

2016-07-01

Wood contains the majority of the nutrients in tropical trees, yet controls over wood nutrient concentrations and their function are poorly understood. We measured wood nutrient concentrations in 106 tree species in 10 forest plots spanning a regional fertility gradient in Panama. For a subset of species, we quantified foliar nutrients and wood density to test whether wood nutrients scale with foliar nutrients at the species level, or wood nutrient storage increases with wood density as predicted by the wood economics spectrum. Wood nutrient concentrations varied enormously among species from fourfold in nitrogen (N) to > 30-fold in calcium (Ca), potassium (K), magnesium (Mg) and phosphorus (P). Community-weighted mean wood nutrient concentrations correlated positively with soil Ca, K, Mg and P concentrations. Wood nutrients scaled positively with leaf nutrients, supporting the hypothesis that nutrient allocation is conserved across plant organs. Wood P was most sensitive to variation in soil nutrient availability, and significant radial declines in wood P indicated that tropical trees retranslocate P as sapwood transitions to heartwood. Wood P decreased with increasing wood density, suggesting that low wood P and dense wood are traits associated with tree species persistence on low fertility soils. Substantial variation among species and communities in wood nutrient concentrations suggests that allocation of nutrients to wood, especially P, influences species distributions and nutrient dynamics in tropical forests. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Wood handbook : wood as an engineering material.

Treesearch

Forest Products Laboratory

1999-01-01

Summarizes information on wood as an engineering material. Presents properties of wood and wood-based products of particular concern to the architect and engineer. Includes discussion of designing with wood and wood-based products along with some pertinent uses.

Wood handbook : wood as an engineering material

Treesearch

Robert J. Ross; Forest Products Laboratory USDA Forest Service.

2010-01-01

Summarizes information on wood as an engineering material. Presents properties of wood and wood-based products of particular concern to the architect and engineer. Includes discussion of designing with wood and wood-based products along with some pertinent uses.

[The influence of oil heat treatment on wood decay resistance by Fourier infrared spectrum analysis].

PubMed

Wang, Ya-Mei; Ma, Shu-Ling; Feng, Li-Qun

2014-03-01

Wood preservative treatment can improve defects of plantation wood such as easy to corrupt and moth eaten. Among them heat-treatment is not only environmental and no pollution, also can improve the corrosion resistance and dimension stability of wood. In this test Poplar and Mongolian Seoteh Pine was treated by soybean oil as heat-conducting medium, and the heat treatment wood was studied for indoor decay resistance; wood chemical components before and after treatment, the effect of heat treatment on wood decay resistance performance and main mechanism of action were analysed by Fourier infrared spectrometric. Results showed that the mass loss rate of poplar fell from 19.37% to 5% and Mongolian Seoteh Pine's fell from 8.23% to 3.15%, so oil heat treatment can effectively improve the decay resistance. Infrared spectrum analysis shows that the heat treatment made wood's hydrophilic groups such as hydroxyl groups in largely reduced, absorbing capacity decreased and the moisture of wood rotting fungi necessary was reduced; during the heat treatment wood chemical components such as cellulose, hemicellu lose were degraded, and the nutrient source of wood rotting fungi growth necessary was reduced. Wood decay fungi can grow in the wood to discredit wood is because of that wood can provide better living conditions for wood decay fungi, such as nutrients, water, oxygen, and so on. The cellulose and hemicellulose in wood is the main nutrition source of wood decay fungi. So the oil heat-treatment can reduce the cellulose, hemicellulose nutrition source of wood decay fungi so as to improve the decay resistance of wood.

Combining hot-compressed water and ball milling pretreatments to improve the efficiency of the enzymatic hydrolysis of eucalyptus

PubMed Central

Inoue, Hiroyuki; Yano, Shinichi; Endo, Takashi; Sakaki, Tsuyoshi; Sawayama, Shigeki

2008-01-01

Background Lignocellulosic biomass such as wood is an attractive material for fuel ethanol production. Pretreatment technologies that increase the digestibility of cellulose and hemicellulose in the lignocellulosic biomass have a major influence on the cost of the subsequent enzymatic hydrolysis and ethanol fermentation processes. Pretreatments without chemicals such as acids, bases or organic solvents are less effective for an enzymatic hydrolysis process than those with chemicals, but they have a less negative effect on the environment. Results The enzymatic digestibility of eucalyptus was examined following a combined pretreatment without chemicals comprising a ball milling (BM) and hot-compressed water (HCW) treatment. The BM treatment simultaneously improved the digestibility of both glucan and xylan, and was effective in lowering the enzyme loading compared with the HCW treatment. The combination of HCW and BM treatment reduced the BM time. The eucalyptus treated with HCW (160°C, 30 minutes) followed by BM (20 minutes) had an approximately 70% yield of total sugar with a cellulase loading of 4 FPU/g substrate. This yield was comparable to the yields from samples treated with HCW (200°C, 30 minutes) or BM (40 minutes) hydrolyzed with 40 FPU/g substrate. Conclusion The HCW treatment is useful in improving the milling efficiency. The combined HCW-BM treatment can save energy and enzyme loading. PMID:18471309

Structural State and Elastic Properties of Perovskites in the Earth's Mantle

NASA Astrophysics Data System (ADS)

Ross, N. L.; Angel, R. J.; Zhao, J.

2005-12-01

Recent advances in laboratory-based single-crystal X-ray diffraction techniques for measuring the intensities of diffraction from crystals held in situ at high pressures in the diamond-anvil cell have been used to determine the role of polyhedral compression in the response of 2:4 and 3:3 GdFeO3-type perovskites to high pressure [1]. These new data clearly demonstrate that, contrary to previous belief, the compression of the octahedral sites is significant and that the evolution of the perovskite structure with pressure is controlled by a new principle; that of equipartition of bond-valence strain across the structure [2]. This new paradigm, together with the minimal information available from high- pressure powder diffraction studies, may provide the possibility of predicting the structural state and elastic properties of perovskites of any composition at mantle pressures and temperatures. Cation partioning between silicate perovskites and other phases should then be predictable through the application of a Brice-style model [3]. The geochemical implications of this type of analysis will be presented as well as the possibility for extending these measurements to higher pressures. References [1] e.g. Zhao, Ross & Angel (2004) Phys Chem Miner. 31: 299; Ross, Zhao,. & Angel (2004). J. Solid State Chemistry 177:1276. [2] Zhao, Ross, & Angel (2004). Acta Cryst. B60:263 [3] e.g Walter et al. (2004) Geochim Cosmochim Acta 68:4267; Blundy & Wood (1994) Nature 372:452

Acoustic and adsorption properties of submerged wood

NASA Astrophysics Data System (ADS)

Hilde, Calvin Patrick

Wood is a common material for the manufacture of many products. Submerged wood, in particular, is used in niche markets, such as the creation of musical instruments. An initial study performed on submerged wood from Ootsa Lake, British Columbia, provided results that showed that the wood was not suitable for musical instruments. This thesis re-examined the submerged wood samples. After allowing the wood to age unabated in a laboratory setting, the wood was retested under the hypothesis that the physical acoustic characteristics would improve. It was shown, however, that the acoustic properties became less adequate after being left to sit. The adsorption properties of the submerged wood were examined to show that the submerged wood had a larger accessible area of wood than that of control wood samples. This implied a lower amount of crystalline area within the submerged wood. From the combined adsorption and acoustic data for the submerged wood, relationships between the moisture content and speed of sound were created and combined with previous research to create a proposed model to describe how the speed of sound varies with temperature, moisture content and the moisture content corresponding to complete hydration of sorption sites within the wood.

Wood as an adherend

Treesearch

Bryan H. River; Charles B. Vick; Robert H. Gillespie

1991-01-01

Wood is a porous, permeable, hygroscopic, orthotropic, biological composite material of extreme chemical diversity and physical intricacy. Table 1.1 provides an overview of the may variables, including wood variables, that bear on the bonding and performance of wood in wood joints and wood-based materials. Of particular note is the fact that wood properties vary...

Integrated control of wood destroying basidiomycetes combining Cu-based wood preservatives and Trichoderma spp.

PubMed Central

2017-01-01

The production of new generation of wood preservatives (without addition of a co-biocide) in combination with an exchange of wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against wood preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on wood colonization and degradation by five wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based preservatives was also examined by mass loss and histological changes in the wood specimens. Trichoderma harzianum (T-720) was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium). T. harzianum demonstrated significant preventative effect on wood specimens against four wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based wood preservatives demonstrated that after 9 months incubation with two wood destroying basidiomycetes, wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55–65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0–25%). Histological studies on one of the wood destroying basidiomycetes revealed typical decomposition of wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in wood specimens previously exposed to T. harzianum. It is concluded that carefully selected Trichoderma isolates can be used for integrated wood protection against a range of wood destroying basidiomycetes and may have potential for integrated wood protection in the field. PMID:28379978

Integrated control of wood destroying basidiomycetes combining Cu-based wood preservatives and Trichoderma spp.

PubMed

Ribera, Javier; Fink, Siegfried; Bas, Maria Del Carmen; Schwarze, Francis W M R

2017-01-01

The production of new generation of wood preservatives (without addition of a co-biocide) in combination with an exchange of wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against wood preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on wood colonization and degradation by five wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based preservatives was also examined by mass loss and histological changes in the wood specimens. Trichoderma harzianum (T-720) was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium). T. harzianum demonstrated significant preventative effect on wood specimens against four wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based wood preservatives demonstrated that after 9 months incubation with two wood destroying basidiomycetes, wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55-65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0-25%). Histological studies on one of the wood destroying basidiomycetes revealed typical decomposition of wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in wood specimens previously exposed to T. harzianum. It is concluded that carefully selected Trichoderma isolates can be used for integrated wood protection against a range of wood destroying basidiomycetes and may have potential for integrated wood protection in the field.

Production of gaseous fuel by pyrolysis of municipal solid waste

NASA Technical Reports Server (NTRS)

Crane, T. H.; Ringer, H. N.; Bridges, D. W.

1975-01-01

Pilot plant tests were conducted on a simulated solid waste which was a mixture of shredded newspaper, wood waste, polyethylene plastics, crushed glass, steel turnings, and water. Tests were conducted at 1400 F in a lead-bath pyrolyser. Cold feed was deaerated by compression and was dropped onto a moving hearth of molten lead before being transported to a sealed storage container. About 80 percent of the feed's organic content was converted to gaseous products which contain over 90 percent of the potential waste energy; 12 percent was converted to water; and 8 percent remained as partially pyrolyzed char and tars. Nearly half of the carbon in the feed is converted to benzene, toluene and medium-quality fuel gas, a potential credit of over $25 per ton of solid waste. The system was shown to require minimal preprocessing and less sorting then other methods.

Graft polymerization of wood sawdust and peat with ethylene carbonate. A novel method for the preparation of supports with enhanced mechanical properties to be used in biofiltration of organic vapors.

PubMed

Hernández-Meléndez, O; Peydecastaing, J; Bárzana, E; Vaca-Garcia, C; Hernández-Luna, M; Borredon, M E

2009-01-01

The graft polymerization reaction between ethylene carbonate (EC) and scots pine sawdust (SPS) or peat moss (PM) offers a solvent-free approach to the simple and inexpensive aliphatic derivatization of these lignocellulosic fibers. This reaction was studied with liquid or vapor EC phases in three different reactor configurations: batch stirred (BSR), semi-continuous stirred (SSR) and continuous tubular in the gas phase (CVTR). The use of a vapor phase allowed a satisfactory grafting yield and minimal production of non-grafted polyol by-products. The crosslinking agent 4,4'-methylenebis(phenylisocyanate) (MDI) achieved superior characteristics to form shaped tablets resistant to water disaggregation, a high water retention capacity and high compression strength, characteristics that conventional organic supports like PM or PM-polyurethane foam mixtures used in biofiltration of waste gases do not completely possess.

Cord Wood Testing in a Non-Catalytic Wood Stove

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butcher, T.; Trojanowski, R.; Wei, G.

EPA Method 28 and the current wood stove regulations have been in-place since 1988. Recently, EPA proposed an update to the existing NSPS for wood stove regulations which includes a plan to transition from the current crib wood fuel to cord wood fuel for certification testing. Cord wood is seen as generally more representative of field conditions while the crib wood is seen as more repeatable. In any change of certification test fuel, there are questions about the impact on measured results and the correlation between tests with the two different fuels. The purpose of the work reported here ismore » to provide data on the performance of a noncatalytic stove with cord wood. The stove selected has previously been certified with crib wood which provides a basis for comparison with cord wood. Overall, particulate emissions were found to be considerably higher with cord wood.« less

Bacterial associations with decaying wood : a review

Treesearch

C. A. Clausen

1996-01-01

Wood-inhabiting bacteria are associated with wood decay and may have an indirect influence on the decay process. Bacteria are able to affect wood permeability, attack wood structure, or work synergistically with other bacteria and soft-rot fungi to predispose wood to fungal attack. Bacteria that can inhabit chemically treated wood are recognized. The natural ability of...

Synthesis and cure kinetics of liquefied wood/phenol/formaldehyde resins

Treesearch

Hui Pan; Todd F. Shupe; Chung-Yun Hse

2008-01-01

Wood liquefaction was conducted at a 2/1 phenol/wood ratio in two different reactors: (1) an atmospheric three-necked flask reactor and (2) a sealed Parr reactor. The liquefied wood mixture (liquefied wood, unreacted phenol, and wood residue) was further condensed with formaldehyde under acidic conditions to synthesize two novolac-type liquefied wood/phenol/...

New species of Ipomoea (Convolvulaceae) from South America

PubMed Central

Wood, John R.I.; Muñoz-Rodríguez, Pablo; Degen, Rosa; Scotland, Robert W.

2017-01-01

Abstract The importance of discovering, describing and cataloguing poorly known species in herbarium collections is discussed. It is a spur to efforts at rediscovery and consequent conservation efforts. The problems faced in describing species from limited material are discussed and our methods and criteria in making a decision are described. Prospects for future novelties are briefly assessed. Fifteen new species are described and illustrated with line drawings and distribution maps: Ipomoea attenuata J.R.I. Wood & Scotland, I. cuscoensis J.R.I. Wood & P. Muñoz, I. dasycarpa J.R.I. Wood & Scotland, I. dolichopoda J.R.I. Wood & R. Degen, I. ensiformis J.R.I.Wood & Scotland, I. fasciculata J.R.I. Wood & Scotland, I. graminifolia J.R.I. Wood & Scotland, I. kraholandica J.R.I. Wood & Scotland, I. longirostra J.R.I. Wood & Scotland, I. revoluta J.R.I. Wood & Scotland, I. scopulina J.R.I. Wood &. Scotland, I. uninervis J.R.I. Wood & Scotland, I. veadeirosii J.R.I. Wood & Scotland, I. velutinifolia J.R.I. Wood & Scotland, I. walteri J.R.I. Wood & Scotland. All species are narrow endemics except I. velutinifolia which is found in Brazil and Peru; of the others, 12 are found in Brazil and one each in Paraguay and Peru. PMID:29118645

Competitive outcomes between wood-decaying fungi are altered in burnt wood.

PubMed

Edman, Mattias; Eriksson, Anna-Maria

2016-06-01

Fire is an important disturbance agent in boreal forests where it creates a wide variety of charred and other types of heat-modified dead wood substrates, yet how these substrates affect fungal community structure and development within wood is poorly understood. We allowed six species of wood-decaying basidiomycetes to compete in pairs in wood-discs that were experimentally burnt before fungal inoculation. The outcomes of interactions in burnt wood differed from those in unburnt control wood for two species:Antrodia sinuosanever lost on burnt wood and won over its competitor in 67% of the trials compared to 40% losses and 20% wins on unburnt wood. In contrast, Ischnoderma benzoinumwon all interactions on unburnt wood compared to 33% on burnt wood. However, the responses differed depending on the identity of the competing species, suggesting an interaction between competitor and substrate type. The observed shift in competitive balance between fungal species probably results from chemical changes in burnt wood, but the underlying mechanism needs further investigation. Nevertheless, the results indicate that forest fires indirectly structure fungal communities by modifying dead wood, and highlight the importance of fire-affected dead wood substrates in boreal forests. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chapter 6: Wood energy and competing wood product markers

Treesearch

Kenneth E. Skog; Robert C. Abt; Karen Abt

2014-01-01

Understanding the effect of expanding wood energy markets is important to all wood-dependent industries and to policymakers debating the implementation of public programs to support the expansion of wood energy generation. A key factor in determining the feasibility of wood energy projects (e.g. wood boiler or pellet plant) is the long-term (i.e. 20-30year) supply...

Wood flour

Treesearch

Craig M. Clemons; Daniel F. Caufield

2005-01-01

The term “wood flour” is somewhat ambiguous. Reineke states that the term wood flour “is applied somewhat loosely to wood reduced to finely divided particles approximating those of cereal flours in size, appearance, and texture”. Though its definition is imprecise, the term wood flour is in common use. Practically speaking, wood flour usually refers to wood particles...

Wood flour

Treesearch

Craig M. Clemons

2010-01-01

The term “wood flour” is somewhat ambiguous. Reineke states that the term wood flour “is applied somewhat loosely to wood reduced to finely divided particles approximating those of cereal flours in size, appearance, and texture.” Though its definition is imprecise, the term wood flour is in common use. Practically speaking, wood flour usually refers to wood particles...

Patterns and determinants of wood physical and mechanical properties across major tree species in China.

PubMed

Zhu, JiangLing; Shi, Yue; Fang, LeQi; Liu, XingE; Ji, ChengJun

2015-06-01

The physical and mechanical properties of wood affect the growth and development of trees, and also act as the main criteria when determining wood usage. Our understanding on patterns and controls of wood physical and mechanical properties could provide benefits for forestry management and bases for wood application and forest tree breeding. However, current studies on wood properties mainly focus on wood density and ignore other wood physical properties. In this study, we established a comprehensive database of wood physical properties across major tree species in China. Based on this database, we explored spatial patterns and driving factors of wood properties across major tree species in China. Our results showed that (i) compared with wood density, air-dried density, tangential shrinkage coefficient and resilience provide more accuracy and higher explanation power when used as the evaluation index of wood physical properties. (ii) Among life form, climatic and edaphic variables, life form is the dominant factor shaping spatial patterns of wood physical properties, climatic factors the next, and edaphic factors have the least effects, suggesting that the effects of climatic factors on spatial variations of wood properties are indirectly induced by their effects on species distribution.

Effects of humidity on the magnetic and woody characteristics of powder-type magnetic wood

NASA Astrophysics Data System (ADS)

Oka, H.; Tokuta, H.; Namizaki, Y.; Sekino, N.

2004-05-01

Among three types of proposed magnetic wood, powder-type magnetic wood can be made of recycled magnetic materials from IT devices, consumer electronics and waste wood. Because of its wood powder content, powder-type magnetic wood shows special characteristics different from those of typical magnetic materials. We focused on the relationship between humidity and magnetic characteristics of powder-type magnetic wood. The magnetic powder ratio, wood powder density and magnetic binder density were all examined as parameters for AC permeability.

Study of influence of 2.4 GHz electromagnetic waves on electrophysical properties of coniferous trees wood

NASA Astrophysics Data System (ADS)

Abdurahimov, Nursulton; Lagunov, Alexey; Melehov, Vladimir

2017-09-01

Climate change has a significant impact on changing weather conditions in the Arctic. Wood is a traditional building material in the North of Russia. Supports of communication lines are made of wood. Dry wood is a solid dielectric with a low conductivity. At the same time it is porous material having high hygroscopicity. The presence of moisture leads to wood rotting. To prevent rotting of a support it needs to be impregnated with antiseptics. A tree dried by means of convection drying cannot provide required porosity of wood for impregnation. Our studies of electrophysical properties of coniferous species showed that microwave drying of wood increases the porosity of the wood. Wood dried in this way is easily impregnated with antiseptics. Thorough wood drying requires creating optimal conditions in a microwave oven. During the drying process in a chamber there is a resonant phenomenon. These phenomena depend on electro-physical properties of the material placed in the chamber. Dielectric constant of wood has the most influence. A resonator method to determine the dielectric constant of the wood was used. The values of permittivity for the spruce and pine samples were determined. The measured value of the dielectric constant of wood was used to provide optimal matching of the generator with the resonator in a wood-drying resonator type microwave chamber, and to maintain it in the process of wood drying. It resulted in obtaining the samples with a higher permeability of wood in radial and longitudinal direction. This creates favorable conditions for wood impregnation with antiseptics and flame retardants. Timber dried by means of electromagnetic waves in the 2.4 GHz band has a deeper protective layer. The support made of such wood will serve longer as supports of communication lines.

FIELD-SCALE LEACHING OF ARSENIC, CHROMIUM AND COPPER FROM WEATHERED TREATED WOOD

PubMed Central

Hasan, A. Rasem; Hu, Ligang; Solo-Gabriele, Helena M.; Fieber, Lynne; Cai, Yong; Townsend, Timothy G.

2010-01-01

Earlier studies documented the loss of wood preservatives from new wood. The objective of this study was to evaluate losses from weathered treated wood under field conditions by collecting rainfall leachate from 5 different wood types, all with a surface area of 0.21 m2. Wood samples included weathered chromate copper arsenate (CCA) treated wood at low (2.7 kg/m3), medium (4.8 kg/m3) and high (35.4 kg/m3) retention levels, new alkaline copper quat (ACQ) treated wood (1.1 kg/m3 as CuO) and new untreated wood. Arsenic was found to leach at a higher rate (100 mg in 1 year for low retention) than chromium and copper (<40 mg) in all CCA treated wood samples. Copper leached at the highest rate from the ACQ sample (670 mg). Overall results suggest that metals’ leaching is a continuous process driven by rainfall, and that the mechanism of release from the wood matrix changes as wood weathers. PMID:20053493

Disentangling the drivers of coarse woody debris behavior and carbon gas emissions during fire

NASA Astrophysics Data System (ADS)

Zhao, Weiwei; van der Werf, Guido R.; van Logtestijn, Richard S. P.; van Hal, Jurgen R.; Cornelissen, Johannes H. C.

2016-04-01

The turnover of coarse woody debris, a key terrestrial carbon pool, plays fundamental roles in global carbon cycling. Biological decomposition and fire are two main fates for dead wood turnover. Compared to slow decomposition, fire rapidly transfers organic carbon from the earth surface to the atmosphere. Both a-biotic environmental factors and biotic wood properties determine coarse wood combustion and thereby its carbon gas emissions during fire. Moisture is a key inhibitory environmental factor for fire. The properties of dead wood strongly affect how it burns either directly or indirectly through interacting with moisture. Coarse wood properties vary between plant species and between various decay stages. Moreover, if we put a piece of dead wood in the context of a forest fuel bed, the soil and wood contact might also greatly affect their fire behavior. Using controlled laboratory burns, we disentangled the effects of all these driving factors: tree species (one gymnosperms needle-leaf species, three angiosperms broad-leaf species), wood decay stages (freshly dead, middle decayed, very strongly decayed), moisture content (air-dried, 30% moisture content in mass), and soil-wood contact (on versus 3cm above the ground surface) on dead wood flammability and carbon gas efflux (CO2 and CO released in grams) during fire. Wood density was measured for all coarse wood samples used in our experiment. We found that compared to other drivers, wood decay stages have predominant positive effects on coarse wood combustion (for wood mass burned, R2=0.72 when air-dried and R2=0.52 at 30% moisture content) and associated carbon gas emissions (for CO2andCO (g) released, R2=0.55 when air-dried and R2=0.42 at 30% moisture content) during fire. Thus, wood decay accelerates wood combustion and its CO2 and CO emissions during fire, which can be mainly attributed to the decreasing wood density (for wood mass burned, R2=0.91 when air-dried and R2=0.63 at 30% moisture content) as wood becomes more decomposed. Our results provide quantitative experimental evidence for how several key abiotic and biotic factors, especially moisture content and the key underlying trait wood density, as well as their interactions, together drive coarse wood carbon turnover through fire. Our experimental data on coarse wood behavior and gas efflux during fire will help to improve the predictive power of global vegetation climate models on dead wood turnover and its feedback to climate.

UV resistance and dimensional stability of wood modified with isopropenyl acetate.

PubMed

Nagarajappa, Giridhar B; Pandey, Krishna K

2016-02-01

Chemical modification of Rubberwood (Hevea brasiliensis Müll.Arg) with isopropenyl acetate (IPA) in the presence of anhydrous aluminum chloride as a catalyst has been carried out under solvent free conditions. The level of modification was estimated by determining the weight percent gain and modified wood was characterized by FTIR-ATR and CP/MAS (13)C NMR spectroscopy. The effect of catalyst concentration on WPG was studied. UV resistance, moisture adsorption and dimensional stability of modified wood were evaluated. UV resistance of modified wood was evaluated by exposing unmodified and modified wood to UV irradiation in a QUV accelerated weathering tester. Unmodified wood showed rapid color changes and degradation of lignin upon exposure to UV light. Chemical modification of wood polymers with IPA was effective in reducing light induced color changes (photo-yellowing) at wood surfaces. In contrast to unmodified wood, modified wood exhibited bleaching. FTIR analysis of modified wood exposed to UV light indicated stabilization of wood polymers against UV degradation. Modified wood showed good dimensional stability and hydrophobicity. Thermogravimetric analysis showed that modification with IPA improved thermal stability of wood. Improved dimensional stability and UV resistance of modified wood indicates IPA as a promising reagent since there is no acid byproduct of reaction as observed in case of other esterification reactions. Copyright © 2015 Elsevier B.V. All rights reserved.

Wood fuel preparation

Treesearch

L. H. Reineke

1965-01-01

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...

Evaluation of interior and exterior latex paints : final report.

DOT National Transportation Integrated Search

1979-10-01

The wood panels that have only one coat of paint over bare wood and one coat of paint over primed wood are continuing to show sighs of deterioration. The wood panels that have two coats of paint over bare wood and two coats of paint over primed wood ...

Wood Programs. Courseware Evaluation for Vocational and Technical Education.

ERIC Educational Resources Information Center

Kaylor, Robert; And Others

This courseware evaluation rates the Wood Programs software developed by the Iowa Department of Public Instruction. (These programs--not contained in this document--include understanding board feet, wood characteristics, wood safety drill, wood dimensions, wood moisture, operating the table saw, radial arm, measurement drill, fraction drill, and…

76 FR 76690 - Multilayered Wood Flooring From the People's Republic of China: Amended Final Determination of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-08

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-970] Multilayered Wood Flooring... is issuing an antidumping duty order on multilayered wood flooring (``wood flooring'') from the... antidumping duty investigation of wood flooring from the PRC. See Multilayered Wood Flooring From the People's...

Corrosion of metals in wood : comparing the results of a rapid test method with long-term exposure tests across six wood treatments

Treesearch

Samuel L. Zelinka; Donald S. Stone

2011-01-01

This paper compares two methods of measuring the corrosion of steel and galvanized steel in wood: a long-term exposure test in solid wood and a rapid test method where fasteners are electrochemically polarized in extracts of wood treated with six different treatments. For traditional wood preservatives, the electrochemical extract method correlates with solid wood...

Methanol from wood waste : a technical and economic study

Treesearch

A. E. Hokanson; R. M. Rowell

1977-01-01

A methanol-from-wood waste facility having a capacity of 50 million gallons per year requires 1,500 ovendry tons (ODT) of wood waste per day. The yield of methanol from wood is about 38 percent, or about 100 gallons per ODT of wood. This yield is based on all process energy required coming from the wood waste. At a wood waste cost of $15/ODT, the selling price of...

The use of new, aqueous chemical wood modifications to improve the durability of wood-plastic composites

Treesearch

Rebecca E. Ibach; Craig M. Clemons; George C. Chen

2017-01-01

The wood flour used in wood-plastic composites (WPCs) can biologically deteriorate and thus the overall mechanical performance of WPCs decrease when exposed to moisture and fungal decay. Protecting the wood flour by chemical modification can improve the durability of the wood in a nontoxic way so it is not harmful to the environment. WPCs were made with modified wood...

Comparative study on liquefaction of creosote and chromated copper arsenate (CCA)-treated wood and untreated southern pine wood: effects of acid catalyst content, liquefaction time, temperature, and phenol to wood ratio

Treesearch

Hui Pan; Chung-Yun Hse; Todd F. Shupe

2009-01-01

Creosote- and chromated copper arsenate (CCA)-treated wood waste and untreated southern pine wood were liquefied with phenol and sulfuric acid. The effects of sulfuric acid content, liquefaction time, liquefaction temperature, and phenol to wood ratio on liquefaction rate (i.e., wood residue content) were investigated and analyzed by analysis of variance (...

Adhesives for Achieving Durable Bonds with Acetylated Wood

Treesearch

Charles Frihart; Rishawn Brandon; James Beecher; Rebecca Ibach

2017-01-01

Acetylation of wood imparts moisture durability, decay resistance, and dimensional stability to wood; however, making durable adhesive bonds with acetylated wood can be more difficult than with unmodified wood. The usual explanation is that the acetylated surface has fewer hydroxyl groups, resulting in a harder-to-wet surface and in fewer hydrogen bonds between wood...

Finishes for Wood Decks

Treesearch

Mark Knaebe

2013-01-01

Wood decks have become an important part of residential construction. Wood decks can add versatile living space to a home and, with minimal maintenance, provide decades of use. However, wood decks are exposed to high levels of stress from severe weather conditions that shrink and swell the wood. Without proper maintenance, wood decks can develop problems such as checks...

Surface characterization

Treesearch

Mandla A. Tshabalala

2005-01-01

Surface properties of wood play an important role when wood is used or processed into different commodities such as siding, joinery, textiles, paper, sorption media or wood composites. Thus, for example, the quality and durability of a wood coating are determined by the surface properties of the wood and the coating. The same is true for wood composites, as the...

Effect of wood flour content on the optical color, surface chemistry, mechanical and morphological properties of wood flour/recycled high density polyethylene (rHDPE) composite

NASA Astrophysics Data System (ADS)

Sheng, Chan Kok; Amin, Khairul Anuar Mat; Kee, Kwa Bee; Hassan, Mohd Faiz; Ali, E. Ghapur E.

2018-05-01

In this study, effect of wood flour content on the color, surface chemistry, mechanical properties and surface morphology of wood-plastic composite (WPC) on different mixture ratios of recycled high density polyethylene (rHDPE) and wood flour were investigated in detail. The presence of wood flour in the composite indicates a significant total color change and a decrease of lightness. Functional groups of wood flour in WPC can be seen clearer from the Fourier transform infrared (FTIR) spectra as the wood flour content increases. The mechanical tensile testing shows that the tensile strength of Young's modulus is improved, whereas the strain and elongation at break were reduced by the addition of wood flour. The gap between the wood flour microvoid fibre and rHDPE matrix becomes closer when the wood flour content is increased as observed by scanning electron microscope (SEM) image. This finding implies a significant improvement on the interaction of interfacial adhesion between the rHDPE matrix and wood flour filler in the present WPC.

Bacterial Community Succession in Pine-Wood Decomposition.

PubMed

Kielak, Anna M; Scheublin, Tanja R; Mendes, Lucas W; van Veen, Johannes A; Kuramae, Eiko E

2016-01-01

Though bacteria and fungi are common inhabitants of decaying wood, little is known about the relationship between bacterial and fungal community dynamics during natural wood decay. Based on previous studies involving inoculated wood blocks, strong fungal selection on bacteria abundance and community composition was expected to occur during natural wood decay. Here, we focused on bacterial and fungal community compositions in pine wood samples collected from dead trees in different stages of decomposition. We showed that bacterial communities undergo less drastic changes than fungal communities during wood decay. Furthermore, we found that bacterial community assembly was a stochastic process at initial stage of wood decay and became more deterministic in later stages, likely due to environmental factors. Moreover, composition of bacterial communities did not respond to the changes in the major fungal species present in the wood but rather to the stage of decay reflected by the wood density. We concluded that the shifts in the bacterial communities were a result of the changes in wood properties during decomposition and largely independent of the composition of the wood-decaying fungal communities.

Bacterial Community Succession in Pine-Wood Decomposition

PubMed Central

Kielak, Anna M.; Scheublin, Tanja R.; Mendes, Lucas W.; van Veen, Johannes A.; Kuramae, Eiko E.

2016-01-01

Though bacteria and fungi are common inhabitants of decaying wood, little is known about the relationship between bacterial and fungal community dynamics during natural wood decay. Based on previous studies involving inoculated wood blocks, strong fungal selection on bacteria abundance and community composition was expected to occur during natural wood decay. Here, we focused on bacterial and fungal community compositions in pine wood samples collected from dead trees in different stages of decomposition. We showed that bacterial communities undergo less drastic changes than fungal communities during wood decay. Furthermore, we found that bacterial community assembly was a stochastic process at initial stage of wood decay and became more deterministic in later stages, likely due to environmental factors. Moreover, composition of bacterial communities did not respond to the changes in the major fungal species present in the wood but rather to the stage of decay reflected by the wood density. We concluded that the shifts in the bacterial communities were a result of the changes in wood properties during decomposition and largely independent of the composition of the wood-decaying fungal communities. PMID:26973611

Functional lignocellulosic materials prepared by ATRP from a wood scaffold.

PubMed

Cabane, Etienne; Keplinger, Tobias; Künniger, Tina; Merk, Vivian; Burgert, Ingo

2016-08-10

Wood, a natural and abundant source of organic polymers, has been used as a scaffold to develop novel wood-polymer hybrid materials. Through a two-step surface-initiated Atom Transfer Radical Polymerization (ATRP), the porous wood structure can be effectively modified with polymer chains of various nature. In the present study, polystyrene and poly(N-isopropylacrylamide) were used. As shown with various characterization techniques including confocal Raman microscopy, FTIR, and SEM/EDX, the native wood ultrastructure and features are retained and the polymer chains can be introduced deep within the wood, i.e. inside the wood cell walls. The physical properties of the new materials have been studied, and results indicate that the insertion of polymer chains inside the wood cell wall alters the intrinsic properties of wood to yield a hybrid composite material with new functionalities. This approach to the functionalization of wood could lead to the fabrication of a new class of interesting functional materials and promote innovative utilizations of the renewable resource wood.

Functional lignocellulosic materials prepared by ATRP from a wood scaffold

PubMed Central

Cabane, Etienne; Keplinger, Tobias; Künniger, Tina; Merk, Vivian; Burgert, Ingo

2016-01-01

Wood, a natural and abundant source of organic polymers, has been used as a scaffold to develop novel wood-polymer hybrid materials. Through a two-step surface-initiated Atom Transfer Radical Polymerization (ATRP), the porous wood structure can be effectively modified with polymer chains of various nature. In the present study, polystyrene and poly(N-isopropylacrylamide) were used. As shown with various characterization techniques including confocal Raman microscopy, FTIR, and SEM/EDX, the native wood ultrastructure and features are retained and the polymer chains can be introduced deep within the wood, i.e. inside the wood cell walls. The physical properties of the new materials have been studied, and results indicate that the insertion of polymer chains inside the wood cell wall alters the intrinsic properties of wood to yield a hybrid composite material with new functionalities. This approach to the functionalization of wood could lead to the fabrication of a new class of interesting functional materials and promote innovative utilizations of the renewable resource wood. PMID:27506369

Comparing the VOC emissions between air-dried and heat-treated Scots pine wood

NASA Astrophysics Data System (ADS)

Manninen, Anne-Marja; Pasanen, Pertti; Holopainen, Jarmo K.

The emissions of volatile organic compounds (VOCs) from air-dried Scots pine wood and from heat-treated Scots pine wood were compared with GC-MS analysis. Air-dried wood blocks released about 8 times more total VOCs than heat-treated (24 h at 230°C) ones. Terpenes were clearly the main compound group in the air-dried wood samples, whereas aldehydes and carboxylic acids and their esters dominated in the heat-treated wood samples. Only 14 compounds out of 41 identified individual compounds were found in both wood samples indicating considerable changes in VOC emission profile during heat-treatment process. Of individual compounds α-pinene, 3-carene and hexanal were the most abundant ones in the air-dried wood. By contrast, in the heat-treated wood 2-furancarboxaldehyde, acetic acid and 2-propanone were the major compounds of VOC emission. Current emission results reveal that significant chemical changes have occurred, and volatile monoterpenes and other low-molecular-weight compounds have evaporated from the wood during the heat-treatment process when compared to air-dried wood. Major chemical changes detected in VOC emissions are explained by the thermal degradation and oxidation of main constituents in wood. The results suggest that if heat-treated wood is used in interior carpentry, emissions of monoterpenes are reduced compared to air-dried wood, but some irritating compounds might be released into indoor air.

Wood adhesives : vital for producing most wood products

Treesearch

Charles R. Frihart

2011-01-01

A main route for the efficient utilization of wood resources is to reduce wood to small pieces and then bond them together (Frihart and Hunt 2010). Although humankind has been bonding wood since early Egyptian civilizations, the quality and quantity of bonded wood products has increased dramatically over the past 100 years with the development of new adhesives and...

Chapter 8:Surface Characterization

Treesearch

Mandla A. Tshabalala; Joseph Jakes; Mark R. VanLandingham; Shaoxia Wang; Jouko Peltonen

2013-01-01

Surface properties of wood play an important role when wood is used or processed into different commodities such as siding, joinery, textiles, paper, sorption media, or wood composites. Thus, for example, the quality and durability of a wood coating are determined by the surface properties of the wood and the coating. The same is true for wood composites where the...

77 FR 69454 - Change in Bank Control Notices; Acquisitions of Shares of a Bank or Bank Holding Company

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-19

..., South Carolina. B. Federal Reserve Bank of Chicago (Colette A. Fried, Assistant Vice President) 230.... Woods, Bluffton, South Carolina, individually and as part of a group acting in concert with Edgar Woods.... Woods, Milton Woods Jr. and Susan H Woods, both of Ridgeland, South Carolina, and J. Eric Woods...

Chapter 02: Basic wood biology—Anatomy for identification

Treesearch

Alex Wiedenhoeft

2011-01-01

Before the topics of using a hand lens, preparing wood for observation, and understanding the characters used in wood identification can be tackled, a general introduction to the biology of wood must be undertaken. The woods in commercial trade in Central America come almost exclusively from trees, so the discussion of wood biology is restricted to trees here, though...

Uses and desirable properties of wood in the 21st century

Treesearch

Theodore Wegner; Kenneth E. Skog; Peter J. Ince; Charles J. Michler

2010-01-01

The desirability of specific wood properties is driven by a number of social, economic, and environmental factors that influence wood-use trends. This article discusses current continuing commercial uses of wood, significant new or emerging commercial uses, and desirable wood properties indicated by projected changes in wood use. Emerging issues and applications such...

Interaction of copper wood preservatives and adhesives

Treesearch

Charles R. Frihart

2003-01-01

Compared to other substrates, wood is generally easy to bond. However, adhesion is diminished when the wood surface is covered by chemicals, whether natural oils and resins or added chemicals. Among the chemicals added to wood are fire retardants and wood preservatives. Chromated copper arsenate (CCA) has been widely used to protect wood against rot and termites, but...

Characterization of Juvenile wood in Lodgepole Pine in the Intermountain West

Treesearch

Thomas M. Gorman; David E. Kretschmann

2012-01-01

Juvenile wood (core wood) is typically characterized as being less dimensionally stable and having lower mechanical properties than mature wood. Determination of the age of transition from juvenile wood to mature wood can provide basic information needed to assess dimensional stability and better utilize small-diameter trees growing in the intermountain west as solid-...

Many Roles of Wood Adhesives

Treesearch

Charles R. Frihart

2014-01-01

Although wood bonding is one of the oldest applications of adhesives, going back to early recorded history (1), some aspects of wood bonds are still not fully understood. Most books in the general area of adhesives and adhesion do not cover wood bonding. However, a clearer understanding of wood bonding and wood adhesives can lead to improved products. This is important...

Thermal decomposition of wood: influence of wood components and cellulose crystallite size.

PubMed

Poletto, Matheus; Zattera, Ademir J; Forte, Maria M C; Santana, Ruth M C

2012-04-01

The influence of wood components and cellulose crystallinity on the thermal degradation behavior of different wood species has been investigated using thermogravimetry, chemical analysis and X-ray diffraction. Four wood samples, Pinus elliottii (PIE), Eucalyptus grandis (EUG), Mezilaurus itauba (ITA) and Dipteryx odorata (DIP) were used in this study. The results showed that higher extractives contents associated with lower crystallinity and lower cellulose crystallite size can accelerate the degradation process and reduce the wood thermal stability. On the other hand, the thermal decomposition of wood shifted to higher temperatures with increasing wood cellulose crystallinity and crystallite size. These results indicated that the cellulose crystallite size affects the thermal degradation temperature of wood species. Copyright © 2012. Published by Elsevier Ltd.

The raft of the Saint-Jean River, Gaspé (Québec, Canada): A dynamic feature trapping most of the wood transported from the catchment

NASA Astrophysics Data System (ADS)

Boivin, Maxime; Buffin-Bélanger, Thomas; Piégay, Hervé

2015-02-01

The rivers of the Gaspé Peninsula, Québec (Canada), a coastal drainage system of the St. Lawrence River, receive and transport vast quantities of large wood. The rapid rate of channel shifting caused by high-energy flows and noncohesive banks allows wood recruitment that in turn greatly influences river dynamics. The delta of the Saint-Jean River has accumulated wood since 1960, leading to frequent avulsions over that time period. The wood raft there is now more than 3-km in length, which is unusual but natural. This jam configuration allows a unique opportunity to estimate a wood budget at the scale of a long river corridor and to better understand the dynamics of large wood (LW) in rivers. A wood budget includes the evaluation of wood volumes (i) produced by bank erosion (input), (ii) still in transit in the river corridor (deposited on sand bars or channel edges), and (iii) accumulated in the delta (output). The budget is based on an analysis of aerial photos dating back to 1963 as well as surveys carried out in 2010, all of which were used to locate and describe large wood accumulations along a 60-km river section. The main results of this paper show that the raft formation in the delta is dynamic and can be massive, but it is a natural process. Considering the estimated wood volume trapped in the delta from 1963 to 2013 (≈ 25,000 m3), two important points are revealed by the quantification of the wood recruitment volume from 1963 to 2004 (≈ 27,000 m3 ± 400 m3) and of the wood volume stored on the bars in 2010 (≈ 5950 m3). First, the recruitment of large wood from lateral migration for the 40-year period can account for the volume of large wood in the delta and in transit. Second, the excess wood volume produced by lateral migration and avulsion represents a minimum estimation of the large wood trapped on the floodplain owing to wood volume that has decomposed and large wood that exited the river system. Rafts are major trapping structures that provide good potential sites to monitor wood delivery from the catchment through time and allow estimations of LW residence time while in transit. These results contribute to understanding the interannual large wood dynamics in the Saint-Jean River and can assist river managers in determining sustainable solutions for coping with the issue of wood rafts in rivers.

Effects of copper amine treatments on mechanical, biological and surface/interphase properties of poly (vinyl chloride)/wood composites

NASA Astrophysics Data System (ADS)

Jiang, Haihong

2005-11-01

The copper ethanolamine (CuEA) complex was used as a wood surface modifier and a coupling agent for wood-PVC composites. Mechanical properties of composites, such as unnotched impact strength, flexural strength and flexural toughness, were significantly increased, and fungal decay weight loss was dramatically decreased by wood surface copper amine treatments. It is evident that copper amine was a very effective coupling agent and decay inhibitor for PVC/wood flour composites, especially in high wood flour loading level. A DSC study showed that the heat capacity differences (DeltaCp) of composites before and after PVC glass transition were reduced by adding wood particles. A DMA study revealed that the movements of PVC chain segments during glass transition were limited and obstructed by the presence of wood molecule chains. This restriction effect became stronger by increasing wood flour content and by using Cu-treated wood flour. Wood flour particles acted as "physical cross-linking points" inside the PVC matrix, resulting in the absence of the rubbery plateau of PVC and higher E', E'' above Tg, and smaller tan delta peaks. Enhanced mechanical performances were attributed to the improved wetting condition between PVC melts and wood surfaces, and the formation of a stronger interphase strengthened by chemical interactions between Cu-treated wood flour and the PVC matrix. Contact angles of PVC solution drops on Cu-treated wood surfaces were decreased dramatically compared to those on the untreated surfaces. Acid-base (polar), gammaAB, electron-acceptor (acid) (gamma +), electron-donor (base) (gamma-) surface energy components and the total surface energies increased after wood surface Cu-treatments, indicating a strong tendency toward acid-base or polar interactions. Improved interphase and interfacial adhesion were further confirmed by measuring interfacial shear strength between wood and the PVC matrix.

The trait contribution to wood decomposition rates of 15 Neotropical tree species.

PubMed

van Geffen, Koert G; Poorter, Lourens; Sass-Klaassen, Ute; van Logtestijn, Richard S P; Cornelissen, Johannes H C

2010-12-01

The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of interspecific variation in species traits on differences in wood decomposition rates remains unknown. In order to fill these gaps, we applied a novel method to study long-term wood decomposition of 15 tree species in a Bolivian semi-evergreen tropical moist forest. We hypothesized that interspecific differences in species traits are important drivers of variation in wood decomposition rates. Wood decomposition rates (fractional mass loss) varied between 0.01 and 0.31 yr(-1). We measured 10 different chemical, anatomical, and morphological traits for all species. The species' average traits were useful predictors of wood decomposition rates, particularly the average diameter (dbh) of the tree species (R2 = 0.41). Lignin concentration further increased the proportion of explained inter-specific variation in wood decomposition (both negative relations, cumulative R2 = 0.55), although it did not significantly explain variation in wood decomposition rates if considered alone. When dbh values of the actual dead trees sampled for decomposition rate determination were used as a predictor variable, the final model (including dead tree dbh and lignin concentration) explained even more variation in wood decomposition rates (R2 = 0.71), underlining the importance of dbh in wood decomposition. Other traits, including wood density, wood anatomical traits, macronutrient concentrations, and the amount of phenolic extractives could not significantly explain the variation in wood decomposition rates. The surprising results of this multi-species study, in which for the first time a large set of traits is explicitly linked to wood decomposition rates, merits further testing in other forest ecosystems.

Changing Face of Wood Science in Modern Era: Contribution of Nanotechnology.

PubMed

Mishra, Pawan Kumar; Giagli, Kyriaki; Tsalagkas, Dimitrios; Mishra, Harshita; Talegaonkar, Sushma; Gryc, Vladimír; Wimmer, Rupert

2018-02-14

Wood science and nanomaterials science interact together in two different aspects; a) fabrication of lignocellulosic nanomaterials derived from wood and plant-based sources and b) surface or bulk wood modification by nanoparticles. In this review, we attempt to visualize the impact of nanoparticles on the wood coating and preservation treatments based on a thorough registration of the patent databases. The study was carried out as an overview of the scientifically most followed trends on nanoparticles utilization in wood science and wood protection depicted by recent universal filed patents. This review is exclusively targeted on the solid (timber) wood as a subject material. Utilization of mainly metal nanoparticles as photoprotection, antibacterial, antifungal, antiabrasive and functional component on wood modification treatments was found to be widely patented. Additionally, an apparent minimization in the emission of volatile organic compounds (VOCs) has been succeeded. Bulk wood preservation and more importantly, wood coating, splay the range of strengthening wood dimensional stability and biological degradation, against moisture absorption and fungi respectively. Nanoparticle materials have addressed various issues of wood science in a more efficient and environmental way than the traditional methods. Nevertheless, abundant tests and regulations are still needed before industrializing or recycling these products. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

DNA Damage among Wood Workers Assessed with the Comet Assay

PubMed Central

Bruschweiler, Evin Danisman; Wild, Pascal; Huynh, Cong Khanh; Savova-Bianchi, Dessislava; Danuser, Brigitta; Hopf, Nancy B.

2016-01-01

Exposure to wood dust, a human carcinogen, is common in wood-related industries, and millions of workers are occupationally exposed to wood dust worldwide. The comet assay is a rapid, simple, and sensitive method for determining DNA damage. The objective of this study was to investigate the DNA damage associated with occupational exposure to wood dust using the comet assay (peripheral blood samples) among nonsmoking wood workers (n = 31, furniture and construction workers) and controls (n = 19). DNA damage was greater in the group exposed to composite wood products compared to the group exposed to natural woods and controls (P < 0.001). No difference in DNA damage was observed between workers exposed to natural woods and controls (P = 0.13). Duration of exposure and current dust concentrations had no effect on DNA damage. In future studies, workers’ exposures should include cumulative dust concentrations and exposures originating from the binders used in composite wood products. PMID:27398027

Characterization of a gel in the cell wall to elucidate the paradoxical shrinkage of tension wood.

PubMed

Clair, Bruno; Gril, Joseph; Di Renzo, Francesco; Yamamoto, Hiroyuki; Quignard, Françoise

2008-02-01

Wood behavior is characterized by high sensibility to humidity and strongly anisotropic properties. The drying shrinkage along the fibers, usually small due to the reinforcing action of cellulosic microfibrils, is surprisingly high in the so-called tension wood, produced by trees to respond to strong reorientation requirements. In this study, nitrogen adsorption-desorption isotherms of supercritically dried tension wood and normal wood show that the tension wood cell wall has a gel-like structure characterized by a pore surface more than 30 times higher than that in normal wood. Syneresis of the tension wood gel explains its paradoxical drying shrinkage. This result could help to reduce technological problems during drying. Potential applications in biomechanics and biomimetics are worth investigating, considering that, in living trees, tension wood produces tensile growth stresses 10 times higher than that of normal wood.

Large wood transport and jam formation in a series of flume experiments

NASA Astrophysics Data System (ADS)

Davidson, S. L.; MacKenzie, L. G.; Eaton, B. C.

2015-12-01

Large wood has historically been removed from streams, resulting in the depletion of in-stream wood in waterways worldwide. As wood increases morphological and hydraulic complexity, the addition of large wood is commonly employed as a means to rehabilitate in-stream habitat. At present, however, the scientific understanding of wood mobilization and transport is incomplete. This paper presents results from a series of four flume experiments in which wood was added to a reach to investigate the piece and reach characteristics that determine wood stability and transport, as well as the time scale required for newly recruited wood to self-organize into stable jams. Our results show that wood transitions from a randomly distributed newly recruited state to a self-organized, or jam-stabilized state, over the course of a single bankfull flow event. Statistical analyses of piece mobility during this transitional period indicate that piece irregularities, especially rootwads, dictate the stability of individual wood pieces; rootwad presence or absence accounts for up to 80% of the variance explained by linear regression models for transport distance. Furthermore, small pieces containing rootwads are especially stable. Large ramped pieces provide nuclei for the formation of persistent wood jams, and the frequency of these pieces in the reach impacts the travel distance of mobile wood. This research shows that the simulation of realistic wood dynamics is possible using a simplified physical model, and also has management implications, as it suggests that randomly added wood may organize into persistent, stable jams, and characterizes the time scale for this transition.

Furniture wood wastes: Experimental property characterisation and burning tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tatano, Fabio; Barbadoro, Luca; Mangani, Giovanna

2009-10-15

Referring to the industrial wood waste category (as dominant in the provincial district of Pesaro-Urbino, Marche Region, Italy), this paper deals with the experimental characterisation and the carrying out of non-controlled burning tests (at lab- and pilot-scale) for selected 'raw' and primarily 'engineered' ('composite') wood wastes. The property characterisation has primarily revealed the following aspects: potential influence on moisture content of local weather conditions at outdoor wood waste storage sites; generally, higher ash contents in 'engineered' wood wastes as compared with 'raw' wood wastes; and relatively high energy content values of 'engineered' wood wastes (ranging on the whole from 3675more » to 5105 kcal kg{sup -1} for HHV, and from 3304 to 4634 kcal kg{sup -1} for LHV). The smoke qualitative analysis of non-controlled lab-scale burning tests has primarily revealed: the presence of specific organic compounds indicative of incomplete wood combustion; the presence exclusively in 'engineered' wood burning tests of pyrroles and amines, as well as the additional presence (as compared with 'raw' wood burning) of further phenolic and containing nitrogen compounds; and the potential environmental impact of incomplete industrial wood burning on the photochemical smog phenomenon. Finally, non-controlled pilot-scale burning tests have primarily given the following findings: emission presence of carbon monoxide indicative of incomplete wood combustion; higher nitrogen oxide emission values detected in 'engineered' wood burning tests as compared with 'raw' wood burning test; and considerable generation of the respirable PM{sub 1} fraction during incomplete industrial wood burning.« less

New views on antidiarrheal effect of wood creosote: is wood creosote really a gastrointestinal antiseptic?

PubMed

Ataka, Koji; Ito, Masafumi; Shibata, Takashi

2005-12-01

Wood creosote, the principal ingredient in Seirogan, has a long history as a known gastrointestinal microbicidal agent. When administered orally, the intraluminal concentration of wood creosote is not sufficiently high to achieve this microbicidal effect. Through further animal tests, we have shown that antimotility and antisecretory actions are the principal antidiarrheal effects of wood creosote. Wood creosote inhibits intestinal secretion induced by enterotoxins by blocking the Cl(-) channel on the intestinal epithelium. Wood creosote also decreases intestinal motility accelerated by mechanical, chemical, or electrical stimulus by the inhibition of the Ca(2+) influx into the smooth muscle cells. In this overview, the antimotility and antisecretory effects of wood creosote are compared with those of loperamide. Wood creosote was observed to inhibit stimulated colonic motility, but not normal jejunal motility. Loperamide inhibits normal jejunal motility, but not stimulated colonic motility. Both wood creosote and loperamide inhibit intestinal secretion accelerated by acetylcholine. Wood creosote was found to have greater antisecretory effects in the colon than loperamide. Based upon these findings, we conclude that the antidiarrheal effects of wood creosote are due to both antisecretory activity in the intestine and antimotility in the colon, but not due to the microbicidal activity as previously thought. Wood creosote was found to have no effects on normal intestinal activity. These conclusions are supported by the results of a recent clinical study comparing wood creosote and loperamide, which concluded that wood creosote was more efficacious in relieving abdominal pain and comparable to loperamide in relieving diarrhea.

Comparing energy use and environmental emissions of reinforced wood doors and steel doors

Treesearch

Lynn Knight; Melissa Huff; Janet I. Stockhausen; Robert J. Ross

2005-01-01

The USDA Forest Service Forest Products Laboratory has patented a technology that incorporates fiberglass-reinforced wood into the structure of wood doors and other wood building products. The process of reinforcing wood doors with epoxy and fiberglass increases the strength and durability of the product. Also, it allows the use of low-value, small-diameter wood which...

Analysis of three-year Wisconsin temperature histories for roof systems using wood, wood-thermoplastic composite, and fiberglass shingles

Treesearch

Jerrold E. Winandy; Cherilyn A. Hatfield

2007-01-01

Temperature histories for various types of roof shingles, wood roof sheathing, rafters, and nonventilated attics were monitored in outdoor attic structures using simulated North American light-framed construction. In this paper, 3-year thermal load histories for wood-based composite roof sheathing, wood rafters, and attics under western redcedar (WRC) shingles, wood-...

Woods from the Miocene Bakate Formation, Ethiopia : anatomical characteristics, estimates of original specific gravity and ecological inferences

Treesearch

E.A. Wheeler; M.C. Wiemann; J.G. Fleagle

2007-01-01

An assemblage of permineralized woods from the Miocene Bakate Formation, Fejej Plain, Ethiopia, is described. This assemblage of twelve wood types differs from other Miocene wood assemblages known from Ethiopia. Cell wall percentages of the woods were determined to estimate the original specific gravities of the woods in order to better understand the Miocene...

Preparation and Characterization of Novolak Phenol Formaldehyde Resin from Liquefied Brown-Rotted Wood

Treesearch

Gai-Yun Li; Chung-Yun Hse; Te-Fu Qin

2012-01-01

The brown-rotted wood was liquefied in phenol with phosphoric acid as catalyst and the resulting liquefied products were condensed with formaldehyde to yield novolak liquefied wood-based phenol formaldehyde resin (LWPF). The results showed that brown-rotted wood could be more easily liquefied than sound wood in phenol. The residue content of liquefied wood decreased...

Structure and function of wood

Treesearch

Alex C. Wiedenhoeft; Regis B. Miller

2005-01-01

Despite the many human uses to which various woods are suited, at a fundamental level wood is a complex biological structure, itself a composite of many chemistries and cell types acting together to serve the needs of the plant. Although humans have striven to understand wood in the context of wood technology, we have often overlooked the key and basic fact that wood...

Review of in-service moisture and temperature conditions in wood-frame buildings

Treesearch

Samuel V. Glass; Anton TenWolde

2007-01-01

This literature review reports in-service moisture and temperature conditions of floor, wall, and roof members of wood-frame buildings and exposed wood decks and permanent wood foundations. A wide variation exists in reported wood moisture content, spanning a range from as low as 2% to well above 30%. Relevant studies are summarized, and measured values of wood...

Effects of wood fiber characteristics on mechanical properties of wood/polypropylene composites

Treesearch

Nicole M. Stark; Robert E. Rowlands

2003-01-01

Commercial wood flour, the most common wood-derived filler for thermoplastics, is produced in a mixture of particle sizes and generally has a lower aspect ratio than wood and other natural fibers. To understand how wood flour and fiber characteristics influence the mechanical properties of polypropylene composites, we first investigated the effect of different sizes of...

Mechanical properties of small-scale wood laminated composite poles

Treesearch

Cheng Piao; Todd F. Shupe; Chung Y. Hse

2004-01-01

Power companies in the United States consume millions of solid wood poles every year. These poles are from high-valued trees that are becoming more expensive and less available. wood laminated composite poles (LCP) are a novel alternative to solid wood poles. LCP consists of trapezoid wood strips that are bonded by a synthetic resin. The wood strips can be made from...

Wood preservatives and pressure-treated wood: considerations for historic-preservation projects

Treesearch

Ronald W. Anthony; Stan T. Lebow

2015-01-01

Wood, an abundant resource throughout most of the world, has been used as a building material for thousands of years. Many historic buildings have been built primarily of wood, and masonry and stone buildings generally have wood elements, both structural and architectural. As a biological material, wood is both remarkably complex and yet quite durable if well...

Method for lowering the VOCS emitted during drying of wood products

DOEpatents

Banerjee, Sujit; Boerner, James Robert; Su, Wei

2000-01-01

The present invention is directed to a method for removal of VOCs from wood products prior to drying the wood products. The method of the invention includes the steps of providing a chamber having an opening for receiving wood and loading the chamber with green wood. The wood is loaded to an extent sufficient to provide a limited headspace in the chamber. The chamber is then closed and the wood is heated in the chamber for a time and at a temperature sufficient to saturate the headspace with moisture and to substantially transfer VOCs from the wood product to the moisture in the headspace.

Temporal dynamics of instream wood in headwater streams draining mixed Carpathian forests

NASA Astrophysics Data System (ADS)

Galia, Tomáš; Šilhán, Karel; Ruiz-Villanueva, Virginia; Tichavský, Radek; Stoffel, Markus

2017-09-01

Instream wood can reside in fluvial systems over varying periods depending on its geographical context, instream position, tree species, piece size, and fluvial environment. In this paper, we investigate the residence time of two typical species representing a majority of instream wood in steep headwaters of the Carpathians and located under mixed forest canopy. Residence times of individual logs were then confronted with other wood parameters (i.e., wood dimensions, mean annual increment rate, tree age, class of wood stabilisation and decay, geomorphic function of wood pieces, and the proportion of the log length within the active channel). Norway spruce (Picea abies (L.) Karst.) samples indicated more than two times longer mean and maximal residence times as compared to European beech (Fagus sylvatica L.) based on the successful cross-dating of 127 logs. Maximum residence time in the headwaters was 128 years for P. abies and 59 years for F. sylvatica. We demonstrate that log age and log diameter played an important role in the preservation of wood in the fluvial system, especially in the case of F. sylvatica instream wood. By contrast, we did not observe any significant trends between wood residence time and total wood length. Instream wood with geomorphic functions (i.e., formation of steps and jams) did not show any differences in residence time as compared to nonfunctional wood. Nevertheless, we found shorter residence times for hillslope-stabilised pieces when compared to pieces located entirely in the channel (either unattached or stabilised by other wood or bed sediments). We also observed changes of instream wood orientation with respect to wood residence time. This suggests some movement of instream wood (i.e., its turning or short-distance transport), including pieces longer than channel width in the steep headwaters studied here (1.5 ≤ W ≤ 3.5 m), over the past few decades.

Method of predicting mechanical properties of decayed wood

DOEpatents

Kelley, Stephen S.

2003-07-15

A method for determining the mechanical properties of decayed wood that has been exposed to wood decay microorganisms, comprising: a) illuminating a surface of decayed wood that has been exposed to wood decay microorganisms with wavelengths from visible and near infrared (VIS-NIR) spectra; b) analyzing the surface of the decayed wood using a spectrometric method, the method generating a first spectral data of wavelengths in VIS-NIR spectra region; and c) using a multivariate analysis to predict mechanical properties of decayed wood by comparing the first spectral data with a calibration model, the calibration model comprising a second spectrometric method of spectral data of wavelengths in VIS-NIR spectra obtained from a reference decay wood, the second spectral data being correlated with a known mechanical property analytical result obtained from the reference decayed wood.

Inhibition and stimulation effects in communities of wood decay fungi: exudates from colonized wood influence growth by other species.

PubMed

Heilmann-Clausen, J; Boddy, L

2005-04-01

The effects of exudates from uncolonized and from partly decayed beech wood on the extension rates of 16 later stage decay fungi were investigated. The partly decayed wood had been colonized by the pyrenomycete Eutypa spinosa, or the basidiomycetes Fomes fomentarius, Stereum hirsutum, and Trametes versicolor, all known as common early decay agents in European beech forests. Sterilized wood pieces were placed onto 0.5% malt agar, opposite to small agar plugs containing the test fungi. The latter showed very variable and species-specific growth responses to the various wood types. The presence of uncolonized wood stimulated extension rates in many species, whereas the four previously decayed wood types had variable stimulatory or inhibitory effects. Wood decayed by S. hirsutum resulted in reduced extension rate, delayed growth, or total inhibition in the majority of species, thus it is suggested that this species uses secondary metabolites in a defensive strategy. A single species was, however, stimulated in the presence of S. hirsutum-decayed wood. In contrast, the presence of wood decayed by F. fomentarius was stimulatory to 45% of the species. The other previously decayed wood types generally resulted in more variable responses, depending upon species. The results are discussed in an ecological context and it is suggested that the exudates from the partly decayed wood that are responsible for the reported effects may function as infochemicals, structuring microbial communities in wood.

Tropical wood resistance to the West Indian drywood termite Cryptotermes brevis: If termites can't chew….

PubMed

Cosme, Lírio; Haro, Marcelo M; Guedes, Nelsa Maria P; Della Lucia, Terezinha Maria C; Guedes, Raul Narciso C

2018-04-01

The importance and impact of invasive species are usually considered based on their economic implications, particularly the direct damage that they cause. The West Indian drywood termite Cryptotermes brevis (Walker) is an example and is a concern in structural lumber, furniture, and other wood products. Despite its importance, its tropical wood preferences and the wood physical characteristics contributing to resistance have not been investigated to date. Here, we developed wood testing units to allow the X-ray recording of termite colonization and then subsequently tested tropical wood resistance to the termite through free-choice and no-choice bioassays using these wood testing units. The relevance of wood density and hardness as determinants of such resistance was also tested, as was termite mandible wear. The wood testing units used allowed the assessment of the termite infestation and wood area loss, enabling subsequent choice bioassays to be performed. While pine (Pinus sp.), jequitiba (Cariniana sp.) and angelim (Hymenolobium petraenum) exhibited the heaviest losses and highest infestations; cumaru (Dipteryx odorata), guariuba (Clarisia racemosa), and purpleheart (Peltogyne sp.) showed the lowest losses and infestations; courbaril (Hymenaea courbaril), eucalyptus (Eucalyptus sp.), and tatajuba (Bagassa guianensis) exhibited intermediary results. Wood hardness and in particular wood density were key determinants of wood resistance to the termites, which exhibited lower infestations associated with greater mandible wear when infesting harder high-density wood. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Amount of leachant and water absorption levels of wood treated with borates and water repellents.

PubMed

Baysal, Ergun; Sonmez, Abdullah; Colak, Mehmet; Toker, Hilmi

2006-12-01

Wood protection efficacy of borates against biological agents, flame retardancy, and suitability to the environment is well known. Since borates can be applied to timber as water based solutions, they are preferred economically as well. Even though they are highly mobile in wood, boron compounds are widely used in timber preservation. Borates migrate in liquid and increase the hygroscopicity of wood in damp conditions. This study deals with the physical restriction of water access in wood by impregnating water repellent agents into wood to limit amount of leachant and water absorption levels of wood after boron treatment. Borates were incorporated with polyethylene glycol-400 (PEG-400) their bulking effect in wood was considered. Results indicated that the amount of leachates from wood treated with borates in PEG-400 was remarkably higher compared to those of wood treated with the aqueous solutions of borates. Water absorption (WA) levels of wood treated with aqueous solutions of borates were higher than those of their treated samples with the solutions in PEG-400. Secondary treatments of wood with the water repellent (WR) chemicals following borate impregnation reduced the leaching of chemicals from wood in water and also WA of the specimens were less than those of the wood treated with only borates from aqueous and PEG solutions. Styrene (St) was the most effective monomer among the other agents used in terms of immobility effect on borates and WA.

Lignin-Retaining Transparent Wood.

PubMed

Li, Yuanyuan; Fu, Qiliang; Rojas, Ramiro; Yan, Min; Lawoko, Martin; Berglund, Lars

2017-09-11

Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt % of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80 wt % of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83 %, haze of 75 %, thermal conductivity of 0.23 W mK -1 , and work-tofracture of 1.2 MJ m -3 (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Particulate matter emissions from combustion of wood in district heating applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghafghazi, S.; Sowlati, T.; Sokhansanj, Shahabaddine

2011-01-01

The utilization of wood biomass to generate district heat and power in communities that have access to this energy source is increasing. In this paper the effect of wood fuel properties, combustion condition, and flue gas cleaning system on variation in the amount and formation of particles in the flue gas of typical district heating wood boilers are discussed based on the literature survey. Direct measurements of particulate matter (PM) emissions from wood boilers with district heating applications are reviewed and presented. Finally, recommendations are given regarding the selection of wood fuel, combustion system condition, and flue gas cleaning systemmore » in district heating systems in order to meet stringent air quality standards. It is concluded that utilization of high quality wood fuel, such as wood pellets produced from natural, uncontaminated stem wood, would generate the least PM emissions compared to other wood fuel types. Particulate matter emissions from grate burners equipped with electrostatic precipitators when using wood pellets can be well below stringent regulatory emission limit such as particulate emission limit of Metro Vancouver, Canada.« less

Lignin‐Retaining Transparent Wood

PubMed Central

Fu, Qiliang; Rojas, Ramiro; Yan, Min; Lawoko, Martin

2017-01-01

Abstract Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light‐transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt % of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80 wt % of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high‐lignin‐content transparent wood with transmittance of 83 %, haze of 75 %, thermal conductivity of 0.23 W mK−1, and work‐tofracture of 1.2 MJ m−3 (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy‐saving buildings. PMID:28719095

Microscopic characterization of tension wood cell walls of Japanese beech (Fagus crenata) treated with ionic liquids.

PubMed

Kanbayashi, Toru; Miyafuji, Hisashi

2016-09-01

Tension wood that is an abnormal part formed in angiosperms has been barely used for wood industry. In this study, to utilize the tension wood effectively by means of liquefaction using ionic liquid, we performed morphological and topochemical determination of the changes in tension wood of Japanese beech (Fagus crenata) during ionic liquid treatment at the cellular level using light microscopy, scanning electron microscopy and confocal Raman microscopy. Ionic liquid treatment induced cell wall swelling in tension wood. Changes in the tissue morphology treated with ionic liquids were different between normal wood and tension wood, moreover the types of ionic liquids. The ionic liquid 1-ethyl-3-methylimidazolium chloride liquefied gelatinous layers rapidly, whereas 1-ethylpyridinium bromide liquefied slowly but delignified selectively. These novel insights into the deconstruction behavior of tension wood cell walls during ionic liquid treatment provide better understanding of the liquefaction mechanism. The obtained knowledge will contribute to development of an effective chemical processing of tension wood using ionic liquids and lead to efficient use of wood resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of citric acid modification of aspen wood on sorption of copper ion

Treesearch

James D. McSweeny; Roger M. Rowell; Soo Hong Min

2006-01-01

Milled aspen wood was thermochemically modified with citric acid for the purpose of improving the copper (Cu2+) ion sorption capacity of the wood when tested in 24-hour equilibrium batch tests. The wood-citric acid adducts provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ ion uptake of the modified wood compared with that...

Delineating pMDI model reactions with loblolly pine via solution-state NMR spectroscopy. Part 1, Catalyzed reactions with wood models and wood polymers

Treesearch

Daniel J. Yelle; John Ralph; Charles R. Frihart

2011-01-01

To better understand adhesive interactions with wood, reactions between model compounds of wood and a model compound of polymeric methylene diphenyl diisocyanate (pMDI) were characterized by solution-state NMR spectroscopy. For comparison, finely ground loblolly pine sapwood, milled-wood lignin and holocellulose from the same wood were isolated and derivatized with...

Wood-boring beetles in homes

Treesearch

V.R. Lewis; S.J. Seybold

2010-01-01

Three groups of wood-boring beetles—powderpost, deathwatch, and false powderpost (Table 1)—invade and damage wood furniture as well as structural and decorative wood inside of buildings. The beetle larvae feed in and do most of the damage to wood, and when they reach the adult stage, they emerge through round exit holes, which they create by chewing through the wood...

Can melamine-based wood primers help in understanding bonded wood durability?

Treesearch

Charles R. Frihart; Jermal G. Chandler

2006-01-01

Melamine–formaldehyde adhesives form wood bonds with exterior durability, and the melamine is more easily studied because of its significant nitrogen content (compared with the lack of nitrogen in wood components). In addition, some melamine–formaldehyde chemicals reduce wood swelling [6], enter into wood cell walls [7], and strengthen them [8]. This information led to...

Common wood decay fungi found in the Caribbean Basin

Treesearch

D. Jean Lodge

2016-01-01

There are hundreds of wood-decay fungi in the Caribbean Basin, but relatively few of these are likely to grow on manmade structures built of wood or wood-composites. The wood-decay fungi of greatest concern are those that cause brown-rot, and especially brown-rot fungi that are resistant to copper-based wood preservatives. Some fungi that grow in the Caribbean and...

Wood Ash Induced pH Changes Strongly Affect Soil Bacterial Numbers and Community Composition

PubMed Central

Bang-Andreasen, Toke; Nielsen, Jeppe T.; Voriskova, Jana; Heise, Janine; Rønn, Regin; Kjøller, Rasmus; Hansen, Hans C. B.; Jacobsen, Carsten S.

2017-01-01

Recirculation of wood ash from energy production to forest soil improves the sustainability of this energy production form as recycled wood ash contains nutrients that otherwise would be lost at harvest. In addition, wood-ash is beneficial to many soils due to its inherent acid-neutralizing capabilities. However, wood ash has several ecosystem-perturbing effects like increased soil pH and pore water electrical conductivity both known to strongly impact soil bacterial numbers and community composition. Studies investigating soil bacterial community responses to wood ash application remain sparse and the available results are ambiguous and remain at a general taxonomic level. Here we investigate the response of bacterial communities in a spruce forest soil to wood ash addition corresponding to 0, 5, 22, and 167 t wood ash ha-1. We used culture-based enumerations of general bacteria, Pseudomonas and sporeforming bacteria combined with 16S rRNA gene amplicon sequencing to valuate soil bacterial responses to wood ash application. Results showed that wood ash addition strongly increased soil pH and electrical conductivity. Soil pH increased from acidic through neutral at 22 t ha-1 to alkaline at 167 t ha-1. Bacterial numbers significantly increased up to a wood ash dose of 22 t ha-1 followed by significant decrease at 167 t ha-1 wood ash. The soil bacterial community composition changed after wood ash application with copiotrophic bacteria responding positively up to a wood ash dose of 22 t ha-1 while the adverse effect was seen for oligotrophic bacteria. Marked changes in bacterial community composition occurred at a wood ash dose of 167 t ha-1 with a single alkaliphilic genus dominating. Additionally, spore-formers became abundant at an ash dose of 167 t ha-1 whereas this was not the case at lower ash doses. Lastly, bacterial richness and diversity strongly decreased with increasing amount of wood ash applied. All of the observed bacterial responses can be directly explained by the wood ash induced changes in pH, electrical conductivity and the addition of wood ash inherent nutrients. PMID:28804476

Wood Ash Induced pH Changes Strongly Affect Soil Bacterial Numbers and Community Composition.

PubMed

Bang-Andreasen, Toke; Nielsen, Jeppe T; Voriskova, Jana; Heise, Janine; Rønn, Regin; Kjøller, Rasmus; Hansen, Hans C B; Jacobsen, Carsten S

2017-01-01

Recirculation of wood ash from energy production to forest soil improves the sustainability of this energy production form as recycled wood ash contains nutrients that otherwise would be lost at harvest. In addition, wood-ash is beneficial to many soils due to its inherent acid-neutralizing capabilities. However, wood ash has several ecosystem-perturbing effects like increased soil pH and pore water electrical conductivity both known to strongly impact soil bacterial numbers and community composition. Studies investigating soil bacterial community responses to wood ash application remain sparse and the available results are ambiguous and remain at a general taxonomic level. Here we investigate the response of bacterial communities in a spruce forest soil to wood ash addition corresponding to 0, 5, 22, and 167 t wood ash ha -1 . We used culture-based enumerations of general bacteria, Pseudomonas and sporeforming bacteria combined with 16S rRNA gene amplicon sequencing to valuate soil bacterial responses to wood ash application. Results showed that wood ash addition strongly increased soil pH and electrical conductivity. Soil pH increased from acidic through neutral at 22 t ha -1 to alkaline at 167 t ha -1 . Bacterial numbers significantly increased up to a wood ash dose of 22 t ha -1 followed by significant decrease at 167 t ha -1 wood ash. The soil bacterial community composition changed after wood ash application with copiotrophic bacteria responding positively up to a wood ash dose of 22 t ha -1 while the adverse effect was seen for oligotrophic bacteria. Marked changes in bacterial community composition occurred at a wood ash dose of 167 t ha -1 with a single alkaliphilic genus dominating. Additionally, spore-formers became abundant at an ash dose of 167 t ha -1 whereas this was not the case at lower ash doses. Lastly, bacterial richness and diversity strongly decreased with increasing amount of wood ash applied. All of the observed bacterial responses can be directly explained by the wood ash induced changes in pH, electrical conductivity and the addition of wood ash inherent nutrients.

Wood nitrogen concentrations in tropical trees: phylogenetic patterns and ecological correlates.

PubMed

Martin, Adam R; Erickson, David L; Kress, W John; Thomas, Sean C

2014-11-01

In tropical and temperate trees, wood chemical traits are hypothesized to covary with species' life-history strategy along a 'wood economics spectrum' (WES), but evidence supporting these expected patterns remains scarce. Due to its role in nutrient storage, we hypothesize that wood nitrogen (N) concentration will covary along the WES, being higher in slow-growing species with high wood density (WD), and lower in fast-growing species with low WD. In order to test this hypothesis we quantified wood N concentrations in 59 Panamanian hardwood species, and used this dataset to examine ecological correlates and phylogenetic patterns of wood N. Wood N varied > 14-fold among species between 0.04 and 0.59%; closely related species were more similar in wood N than expected by chance. Wood N was positively correlated with WD, and negatively correlated with log-transformed relative growth rates, although these relationships were relatively weak. We found evidence for co-evolution between wood N and both WD and log-transformed mortality rates. Our study provides evidence that wood N covaries with tree life-history parameters, and that these patterns consistently co-evolve in tropical hardwoods. These results provide some support for the hypothesized WES, and suggest that wood is an increasingly important N pool through tropical forest succession. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Wood Technology: Techniques, Processes, and Products

ERIC Educational Resources Information Center

Oatman, Olan

1975-01-01

Seven areas of wood technology illustrates applicable techniques, processes, and products for an industrial arts woodworking curriculum. They are: wood lamination; PEG (polyethylene glycol) diffusion processes; wood flour and/or particle molding; production product of industry; WPC (wood-plastic-composition) process; residential construction; and…

A comparative study between hot-melt extrusion and spray-drying for the manufacture of anti-hypertension compatible monolithic fixed-dose combination products.

PubMed

Kelleher, J F; Gilvary, G C; Madi, A M; Jones, D S; Li, S; Tian, Y; Almajaan, A; Senta-Loys, Z; Andrews, G P; Healy, A M

2018-07-10

The purpose of this work was to investigate the application of different advanced continuous processing techniques (hot melt extrusion and spray drying) to the production of fixed-dose combination (FDC) monolithic systems comprising of hydrochlorothiazide and ramipril for the treatment of hypertension. Identical FDC formulations were manufactured by the two different methods and were characterised using powder X-ray diffraction (PXRD) and modulated differential scanning calorimetry (mDSC). Drug dissolution rates were investigated using a Wood's apparatus, while physical stability was assessed on storage under controlled temperature and humidity conditions. Interestingly both drugs were transformed into their amorphous forms when spray dried, however, hydrochlorothiazide was determined, by PXRD, to be partially crystalline when hot melt extruded with either polymer carrier (Kollidon® VA 64 or Soluplus®). Hot melt extrusion was found to result in significant degradation of ramipril, however, this could be mitigated by the inclusion of the plasticizer, polyethylene glycol 3350, in the formulation and appropriate adjustment of processing temperature. The results of intrinsic dissolution rate studies showed that hot-melt extruded samples were found to release both drugs faster than identical formulations produced via spray drying. However, the differences were attributable to the surface roughness of the compressed discs in the Wood's apparatus, rather than solid state differences between samples. After a 60-day stability study spray dried samples exhibited a greater physical stability than the equivalent hot melt extruded samples. Copyright © 2018 Elsevier B.V. All rights reserved.

36 CFR 13.1110 - May I collect or burn interstadial wood?

Code of Federal Regulations, 2010 CFR

2010-07-01

... interstadial wood? 13.1110 Section 13.1110 Parks, Forests, and Public Property NATIONAL PARK SERVICE... and Preserve General Provisions § 13.1110 May I collect or burn interstadial wood? Collecting or burning interstadial wood (aged wood preserved in glacial deposits) is prohibited. ...

36 CFR 13.1110 - May I collect or burn interstadial wood?

Code of Federal Regulations, 2011 CFR

2011-07-01

... interstadial wood? 13.1110 Section 13.1110 Parks, Forests, and Public Property NATIONAL PARK SERVICE... and Preserve General Provisions § 13.1110 May I collect or burn interstadial wood? Collecting or burning interstadial wood (aged wood preserved in glacial deposits) is prohibited. ...

X-RAY DENSITOMETRY OF NORWAY SPRUCE SUBFOSSIL WOOD FROM THE AUSTRIAN ALPS

PubMed Central

KŁUSEK, MARZENA; GRABNER, MICHAEL

2016-01-01

The processing of subfossil wood poses some difficulties in densitometric research. Problems arise because of the physio-chemical changes of wood occurring in the sedimentation environment. Subfossil wood modification can result from the uptake of mineral and organic substances into the wood tissue. It can also occur as the effect of microbiological degradation of wood. The goal of this study was to identify the appropriate method of subfossil wood preparation for the densitometric research. For this purpose the wood of Norway spruce from Lake Schwarzensee was subjected to extraction in deionized water, acetone and diluted acetic acid. The application of acetic acid did not significantly influence the density of the wood and acetone seemed to be too aggressive. The best result was obtained by rinsing the samples in cold de-ionized water. This extraction procedure allowed removal of unwanted water-soluble, organic and inorganic compounds from wood and simultaneously did not lead to the degradation of subfossil samples. PMID:27158247

Wood Export and Deposition Dynamics in Mountain Watersheds

NASA Astrophysics Data System (ADS)

Senter, Anne Elizabeth

Wood dynamics that store, transport, break down, and ultimately export wood pieces through watershed networks are key elements of stream complexity and ecosystem health. Efforts to quantify wood processes are advancing rapidly as technological innovations in field data collection, remotely sensed data acquisition, and data analyses become increasingly sophisticated. The ability to extend the temporal and spatial scales of wood data acquisition has been particularly useful to the investigations presented herein. The primary contributions of this dissertation are focused on two aspects of wood dynamics: watershed-scale wood export processes as identified using the depositional environment of a mountain reservoir, and wood deposition mechanisms in a bedrock-dominated mountain river. Three chapters present this work: In Chapter 1, continuous video monitoring of wood in transport revealed seasonal and diurnal hydrologic cycle influences on the variable rates at which wood transports. This effort supports the efficacy of utilizing continuous data collection methods for wood transport studies. Annual wood export data were collected via field efforts and aerial image analyses from New Bullards Bar Reservoir on the North Yuba River, Sierra Nevada, California. Examination of data revealed linkages between decadal-scale climatic patterns, large flood events, and episodic wood export quantities. A watershed-specific relation between wood export quantities and annual peak discharge contributes to the notion that peak discharge is a primary control on wood export, and yielded prediction of annual wood export quantities where no data were available. Linkages between seasonality, climatic components, and hydrologic events that exert variable control on watershed scale wood responses are presented as a functional framework. An accompanying conceptual model supports the framework presumption that wood responses are influenced by seasonal variations in Mediterranean-montane climate conditions and accompanying hydrologic responses. Chapter 2 contains development of new theory in support of the introduction of multiplicative coefficients, categorized by water year type, that were used to predict wood export quantities via utilization of an existing discharge-based theoretical equation. This new theory was the product of continued investigations into watershed-scale factors in search of explanation of observed variation of wood export rates into New Bullards Bar Reservoir. The gap between known variability and the attribution of wood export to one hydrologic relation continues to be a persistent issue, as the hierarchical and stochastic temporal and spatial nature of wood budget components remain difficult to quantify. The development of "watershed processes" coefficients was specifically focused on a generalized, parsimonious approach using water year type categories, with validation exercises supporting the approach. In dry years, predictions more closely represented observed wood export quantities, whereas the previously derived annual peak discharge relation yielded large over-predictions. Additional data are needed to continue development of these watershed-specific coefficients. This new approach to wood export prediction may be beneficial in regulated river systems for planning purposes, and its efficacy could be tested in other watersheds. Chapter 3 presents the results of an investigation into wood deposition mechanisms in a 12.2 km segment of the confined, bedrock-dominated South Yuba River watershed. Inclusion of coarse wood particles in the analyses was essential in recognizing depositional patterns, thus supporting the value of utilizing a wider wood-size range. A near-census data collection effort yielded myriad data, of which topographic wetted width and bed elevation data, developed for an observed 4.5-year flood event, were standardized in 10-m intervals and then univariate and linked values were ordered into landform classifications using decision tree analyses. Digital imagery collected via kite-blimp was mosaicked into a geographic information system and all resolvable wood pieces greater then 2.5 cm in one dimension were delineated and categorized into piece count density classes. Visual imagery was also key in identifying two river corridor terrains: bedrock outcrops and cobble-boulder-vegetation patches. A conceptual model framed an investigation into how topographic variability and structural elements might influence observed wood deposition dynamics. Forage ratio test results that quantified wood piece utilization versus interval availability revealed that high-density wood deposition patterns were most significantly co-located with five discrete bedrock outcrops that dominated small portions of the river corridor in high flow conditions. Topographic variations and cobble-boulder-vegetation patches were found to be subordinate factors in wood deposition patterns. Bedrock outcrops with specific structural components were the primary depositional environments that acted as floodplain extents for coarse wood deposition, with mechanisms such as topographic steering, eddying, trapping, stranding, backwater effects, and lateral roughness features inferred to be responsible for observed wood deposition patterns.

The Fungal Degradation of Wood and Wood Products Selected Bibliography

DTIC Science & Technology

1981-08-01

Pi 0-Alt^Jihi 1 TECHNICAL LIBRARY SPECIAL PUBLICATION ARLCD-SP-81006 THE FUNGAL DEGRADATION OF WOOD AND WOOD PRODUCTS SELECTED BIBLIOGRAPHY...GOVT ACCESSION NO. READ INSTRUCTIONS BEFORE COMPLETING FORM 3. RECIPIENT’S CATALOG NUMBER 4. TITLE fand SubJltJo; THE FUNGAL DEGRADATION OF...search con- centrated on the microbiological deterioration or degradation of wood (trees) or wood products which are found or used in tropical

Continued growth expected for wood energy despite turbulence of the economic crisis : wood energy markets, 2008-2009

Treesearch

Rens Hartkamp; Bengt Hillring; Warren Mabee; Olle Olsson; Kenneth Skog; Henry Spelter; Johan Vinterback; Antje Wahl

2009-01-01

The economic crisis has not reduced the demand for wood energy, which is expected to continue to grow. The downturn in sawmill production caused a shortage of raw material supply for wood pellet producers. With decreased demand for pulpwood-quality roundwood for wood and paper products in 2009, some pulpwood is being converted into wood energy. Economies of scale are...

Black Swan Event Assessment for Fort Leonard Wood, Missouri

DTIC Science & Technology

2016-03-01

Fort Leonard Wood ERDC/CERL SR-16-1 March 2016 Black Swan Event Assessment for Fort Leonard Wood , Missouri James D. Westervelt Construction ...ER D C/ CE RL S R- 16 -1 Net Zero Planning for Fort Leonard Wood Black Swan Event Assessment for Fort Leonard Wood , Missouri Co ns... Wood ” ERDC/CERL SR-16-1 ii Abstract Emergency preparation typically involves evaluating disaster potential and consequences, followed by

Woodmetrics: imaging devices and processes in wood inspection at Lulea University of Technology

NASA Astrophysics Data System (ADS)

Hagman, Olle

1999-09-01

Wood Technology research and education at Lulea University of Technology is located in Skelleftea 800 km north of Stockholm. At the campus about 25 persons are involved in education and research in Wood Technology. We are educating M.Sc. and post- graduate students in Wood Technology. The research at the campus includes the following main fields: -- Wood Machining - - Woodmetrics -- Wood Drying -- Wood Composites/Wood Material Science. Our research strategy is to obtain an individual treatment of every tree, board and piece of wood in order to get highest possible value for the forest products. This shall be accomplished by the aid of advanced scanning technology and computer technology. Woodmetrics means to measure different wood parameters in order to optimize the utilization of the raw material. Today we have the following projects in this field: Automatic wood inspection -- Color changes and moisture flow in drying processes -- Inner quality of logs and lumber - - Stem quality database -- Computer tomography -- Aesthetic properties of wood -- Market/industry/forest relations. In the Woodmetrics field we are using computer tomography, CCD cameras and other sensors in order to find and measure defects in trees and on boards. The signals are analyzed and classified with modern image analyzing techniques and advanced statistical methods.

Protection of Wood from Microorganisms by Laccase-Catalyzed Iodination

PubMed Central

Engel, J.; Thöny-Meyer, L.; Schwarze, F. W. M. R.; Ihssen, J.

2012-01-01

In the present work, Norway spruce wood (Picea abies L.) was reacted with a commercial Trametes versicolor laccase in the presence of potassium iodide salt or the phenolic compounds thymol and isoeugenol to impart an antimicrobial property to the wood surface. In order to assess the efficacy of the wood treatment, a leaching of the iodinated and polymerized wood and two biotests including bacteria, a yeast, blue stain fungi, and wood decay fungi were performed. After laccase-catalyzed oxidation of the phenols, the antimicrobial effect was significantly reduced. In contrast, the enzymatic oxidation of iodide (I−) to iodine (I2) in the presence of wood led to an enhanced resistance of the wood surface against all microorganisms, even after exposure to leaching. The efficiency of the enzymatic wood iodination was comparable to that of a chemical wood preservative, VP 7/260a. The modification of the lignocellulose by the laccase-catalyzed iodination was assessed by the Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) technique. The intensities of the selected lignin-associated bands and carbohydrate reference bands were analyzed, and the results indicated a structural change in the lignin matrix. The results suggest that the laccase-catalyzed iodination of the wood surface presents an efficient and ecofriendly method for wood protection. PMID:22865075

Large wood recruitment and redistribution in headwater streams in the southern Oregon Coast Range, U.S.A

USGS Publications Warehouse

May, Christine L.; Gresswell, Robert E.

2003-01-01

Large wood recruitment and redistribution mechanisms were investigated in a 3.9 km2 basin with an old-growth Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. forest, located in the southern Coast Range of Oregon. Stream size and topographic setting strongly influenced processes that delivered wood to the channel network. In small colluvial channels draining steep hillslopes, processes associated with slope instability dominated large wood recruitment. In the larger alluvial channel, windthrow was the dominant recruitment process from the local riparian area. Consequently, colluvial channels received wood from further upslope than the alluvial channel. Input and redistribution processes influenced piece location relative to the direction of flow and thus, affected the functional role of wood. Wood recruited directly from local hillslopes and riparian areas was typically positioned adjacent to the channel or spanned its full width, and trapped sediment and wood in transport. In contrast, wood that had been fluvially redistributed was commonly located in mid-channel positions and was associated with scouring of the streambed and banks. Debris flows were a unique mechanism for creating large accumulations of wood in small streams that lacked the capacity for abundant fluvial transport of wood, and for transporting wood that was longer than the bank-full width of the channel.

Penetration and Effectiveness of Micronized Copper in Refractory Wood Species

PubMed Central

Civardi, Chiara; Van den Bulcke, Jan; Schubert, Mark; Michel, Elisabeth; Butron, Maria Isabel; Boone, Matthieu N.; Dierick, Manuel; Van Acker, Joris; Wick, Peter; Schwarze, Francis W. M. R.

2016-01-01

The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3·Cu(OH)2), with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH)2 particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect. PMID:27649315

Penetration and Effectiveness of Micronized Copper in Refractory Wood Species.

PubMed

Civardi, Chiara; Van den Bulcke, Jan; Schubert, Mark; Michel, Elisabeth; Butron, Maria Isabel; Boone, Matthieu N; Dierick, Manuel; Van Acker, Joris; Wick, Peter; Schwarze, Francis W M R

2016-01-01

The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3·Cu(OH)2), with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH)2 particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect.

Evaluating landfill disposal of chromated copper arsenate (CCA) treated wood and potential effects on groundwater: evidence from Florida.

PubMed

Saxe, Jennifer K; Wannamaker, Eric J; Conklin, Scott W; Shupe, Todd F; Beck, Barbara D

2007-01-01

Chromated copper arsenate (CCA) treated wood has been used for more than 50 years. Recent attention has been focused on appropriate disposal of CCA-treated wood when its service life ends. Groups in the US and Europe concerned with the possibility of arsenic migration to groundwater from disposed CCA-treated wood have proposed that consumers be required to dispose of the wood as a hazardous waste, in the most protective of landfills. We examined available data for evidence of arsenic migration from unlined construction and demolition (C&D) debris landfills in Florida, where CCA-treated wood is disposed. Florida was chosen because soil, groundwater, landfill design, weather, and levels of CCA-treated wood use make the state a uniquely sensitive indicator for observing arsenic migration from CCA-treated wood disposal sites, should it occur. We developed and quality-checked a CCA-treated wood disposal model to estimate the amount of wood and associated arsenic disposed. By 2000, an estimated 13 million kg of arsenic in CCA-treated wood was disposed in Florida; however, groundwater monitoring data do not indicate that arsenic is migrating from unlined C&D landfills. Our results provide evidence that highly stringent regulation of CCA-treated wood disposal, such as treatment as a hazardous waste, is unnecessary.

Significance of wood terpenoids in the resistance of Scots pine provenances against the old house borer, Hylotrupes bajulus, and brown-rot fungus, Coniophora puteana.

PubMed

Nerg, A M; Heijari, J; Noldt, U; Viitanen, H; Vuorinen, M; Kainulainen, P; Holopainen, J K

2004-01-01

We tested how terpenoid (i.e., monoterpenes and resin acids) composition and concentration in wood affects resistance against wood-borers and decaying fungi. Scots pine (Pinus sylvestris) wood from nine provenances having variable terpenoid profiles was studied against the old house borer, Hylotrupes bajulus, and the decay fungus, Coniophora puteana. Provenances represented a 1200-km N-S transect from Estonia to northern Finland, but they were all cultivated for 7 years in the same nursery field, in central Finland. Mean relative growth rate (MRGR) of small H. hajulus larvae positively correlated with the total monoterpene concentration of wood, and feeding was associated with high proportion of levopimaric+palustric acid in wood. Provenance did not affect the MRGR of small or big larvae, but big larvae consumed more wood and produced more frass on the northern Ylitornio trees than on the southern Rakvere and Ruokolahti trees. Low beta-pinene and total monoterpene concentration and low beta: alpha-pinene ratio in wood were all associated with a high number of eggs. The most northern Muonio provenance was the most favored as an oviposition site, differing significantly from Saaremaa, Tenhola, and Suomussalmi. Wood from Saaremaa, Tenhola, Ruokolahti, and Suomussalmi provenance was most resistant against decay fungus, differing significantly from that of Kinnula provenance. However, decay resistance was not clearly associated with the concentrations of wood terpenoids. These results suggest that monoterpene composition of wood affects resistance against wood-boring Cerambycid beetles, but resistance against wood-decaying fungi is not as clearly associated with wood terpenoids.

Resilient 3D hierarchical architected metamaterials

PubMed Central

Meza, Lucas R.; Zelhofer, Alex J.; Clarke, Nigel; Mateos, Arturo J.; Kochmann, Dennis M.; Greer, Julia R.

2015-01-01

Hierarchically designed structures with architectural features that span across multiple length scales are found in numerous hard biomaterials, like bone, wood, and glass sponge skeletons, as well as manmade structures, like the Eiffel Tower. It has been hypothesized that their mechanical robustness and damage tolerance stem from sophisticated ordering within the constituents, but the specific role of hierarchy remains to be fully described and understood. We apply the principles of hierarchical design to create structural metamaterials from three material systems: (i) polymer, (ii) hollow ceramic, and (iii) ceramic–polymer composites that are patterned into self-similar unit cells in a fractal-like geometry. In situ nanomechanical experiments revealed (i) a nearly theoretical scaling of structural strength and stiffness with relative density, which outperforms existing nonhierarchical nanolattices; (ii) recoverability, with hollow alumina samples recovering up to 98% of their original height after compression to ≥50% strain; (iii) suppression of brittle failure and structural instabilities in hollow ceramic hierarchical nanolattices; and (iv) a range of deformation mechanisms that can be tuned by changing the slenderness ratios of the beams. Additional levels of hierarchy beyond a second order did not increase the strength or stiffness, which suggests the existence of an optimal degree of hierarchy to amplify resilience. We developed a computational model that captures local stress distributions within the nanolattices under compression and explains some of the underlying deformation mechanisms as well as validates the measured effective stiffness to be interpreted as a metamaterial property. PMID:26330605

Resilient 3D hierarchical architected metamaterials.

PubMed

Meza, Lucas R; Zelhofer, Alex J; Clarke, Nigel; Mateos, Arturo J; Kochmann, Dennis M; Greer, Julia R

2015-09-15

Hierarchically designed structures with architectural features that span across multiple length scales are found in numerous hard biomaterials, like bone, wood, and glass sponge skeletons, as well as manmade structures, like the Eiffel Tower. It has been hypothesized that their mechanical robustness and damage tolerance stem from sophisticated ordering within the constituents, but the specific role of hierarchy remains to be fully described and understood. We apply the principles of hierarchical design to create structural metamaterials from three material systems: (i) polymer, (ii) hollow ceramic, and (iii) ceramic-polymer composites that are patterned into self-similar unit cells in a fractal-like geometry. In situ nanomechanical experiments revealed (i) a nearly theoretical scaling of structural strength and stiffness with relative density, which outperforms existing nonhierarchical nanolattices; (ii) recoverability, with hollow alumina samples recovering up to 98% of their original height after compression to ≥ 50% strain; (iii) suppression of brittle failure and structural instabilities in hollow ceramic hierarchical nanolattices; and (iv) a range of deformation mechanisms that can be tuned by changing the slenderness ratios of the beams. Additional levels of hierarchy beyond a second order did not increase the strength or stiffness, which suggests the existence of an optimal degree of hierarchy to amplify resilience. We developed a computational model that captures local stress distributions within the nanolattices under compression and explains some of the underlying deformation mechanisms as well as validates the measured effective stiffness to be interpreted as a metamaterial property.

Mechanical Properties of Additively Manufactured Thick Honeycombs.

PubMed

Hedayati, Reza; Sadighi, Mojtaba; Mohammadi Aghdam, Mohammad; Zadpoor, Amir Abbas

2016-07-23

Honeycombs resemble the structure of a number of natural and biological materials such as cancellous bone, wood, and cork. Thick honeycomb could be also used for energy absorption applications. Moreover, studying the mechanical behavior of honeycombs under in-plane loading could help understanding the mechanical behavior of more complex 3D tessellated structures such as porous biomaterials. In this paper, we study the mechanical behavior of thick honeycombs made using additive manufacturing techniques that allow for fabrication of honeycombs with arbitrary and precisely controlled thickness. Thick honeycombs with different wall thicknesses were produced from polylactic acid (PLA) using fused deposition modelling, i.e., an additive manufacturing technique. The samples were mechanically tested in-plane under compression to determine their mechanical properties. We also obtained exact analytical solutions for the stiffness matrix of thick hexagonal honeycombs using both Euler-Bernoulli and Timoshenko beam theories. The stiffness matrix was then used to derive analytical relationships that describe the elastic modulus, yield stress, and Poisson's ratio of thick honeycombs. Finite element models were also built for computational analysis of the mechanical behavior of thick honeycombs under compression. The mechanical properties obtained using our analytical relationships were compared with experimental observations and computational results as well as with analytical solutions available in the literature. It was found that the analytical solutions presented here are in good agreement with experimental and computational results even for very thick honeycombs, whereas the analytical solutions available in the literature show a large deviation from experimental observation, computational results, and our analytical solutions.

Design, fabrication, and implementation of thermally driven outdoor testing devices for building joint sealants.

PubMed

White, C C; Tan, K T; O'Brien, E P; Hunston, D L; Chin, J W; Williams, R S

2011-02-01

The paper describes the development, implementation, and testing of two thermally driven outdoor exposure instruments. These devices are unique in their ability to impose field generated thermally induced strain on sealant specimens while monitoring their resulting load and displacement. The instruments combine a fixed wood and steel supporting frame with a moving polyvinyl chloride frame, and employ differences in the coefficients of thermal expansion between the supporting frame and moving frame to induce strain on the sealant specimens. Two different kinds of instruments have been fabricated, "winter/tension" and "winter/compression" designs. In the winter/tension design, the thermally induced dimensional change is directly transferred to the specimens; while in the winter/compression design, the samples are loaded in an opposite direction with the dimensional change. Both designs are instrumented to monitor load and displacement and are built so that the strain on the specimen does not exceed ±25% over the range of temperatures expected in Gaithersburg, MD. Additionally, a weather station is colocated with the device to record environmental conditions in 1 min intervals. This combination of weather information with mechanical property data enables a direct link between environmental conditions and the corresponding sealant response. The reliability and effectiveness of these instruments are demonstrated with a typical sealant material. The results show that the instruments work according to the design criteria and provide a meaningful quantitative platform to monitor the mechanical response of sealant exposed to outdoor weathering.

Instream wood loads in montane forest streams of the Colorado Front Range, USA

NASA Astrophysics Data System (ADS)

Jackson, Karen J.; Wohl, Ellen

2015-04-01

Although several studies examine instream wood loads and associated geomorphic effects in streams of subalpine forests in the U.S. Southern Rocky Mountains, little is known of instream wood loads in lower elevation, montane forests of the region. We compare instream wood loads and geomorphic effects between streams draining montane forest stands of differing age (old growth versus younger) and disturbance history (healthy versus infested by mountain pine beetles). We examined forest stand characteristics, instream wood load, channel geometry, pool volume, and sediment storage in 33 pool-riffle or plane-bed stream reaches with objectives of determining whether (i) instream wood and geomorphic effects differed significantly among old-growth, younger, healthy, and beetle-infested forest stands and (ii) wood loads correlated with valley and channel characteristics. Wood loads were standardized to drainage area, stream gradient, reach length, bankfull width, and floodplain area. Streams flowing through old-growth forests had significantly larger wood loads and logjam volumes (pairwise t-tests), as well as logjam frequencies (Kruskal-Wallis test), residual pool volume, and fine sediment storage around wood than streams flowing through younger forests. Wood loads in streams draining beetle-infested forest did not differ significantly from those in healthy forest stands, but best subset regression models indicated that elevation, stand age, and beetle infestation were the best predictors of wood loads in channels and on floodplains, suggesting that beetle infestation is affecting instream wood characteristics. Wood loads are larger than values from subalpine streams in the same region and jams are larger and more closely spaced. We interpret these differences to reflect greater wood piece mobility in subalpine zone streams. Stand age appears to exert the dominant influence on instream wood characteristics within pool-riffle streams in the study area rather than beetle infestation, although this may reflect the relatively recent nature (< 10 years) of the infestation.

76 FR 26685 - Multilayered Wood Flooring From the People's Republic of China: Alignment of Final Countervailing...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-09

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-971] Multilayered Wood Flooring... determination in this countervailing duty investigation of multilayered wood flooring (``wood flooring'') from... simultaneously initiated antidumping and countervailing duty investigations of wood flooring from the PRC. See...

Oxalate analysis methodology for decayed wood

Treesearch

Carol A. Clausen; William Kenealy; Patricia K. Lebow

2008-01-01

Oxalate from partially decayed southern pine wood was analyzed by HPLC or colorimetric assay. Oxalate extraction efficiency, assessed by comparing analysis of whole wood cubes with ground wood, showed that both wood geometries could be extracted with comparable efficiency. To differentiate soluble oxalate from total oxalate, three extraction methods were assessed,...

40 CFR 429.80 - Applicability; description of the wood preserving-steam subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Applicability; description of the wood... Wood Preserving Steam Subcategory § 429.80 Applicability; description of the wood preserving—steam... process wastewater pollutants into publicly owned treatment works from wood preserving processes that use...

40 CFR 429.90 - Applicability; description of the wood preserving-Boulton subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Applicability; description of the wood... CATEGORY Wood Preserving-Boulton Subcategory § 429.90 Applicability; description of the wood preserving... introduction of process wastewater pollutants into a publicly owned treatment works from wood preserving...

40 CFR 429.90 - Applicability; description of the wood preserving-Boulton subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Applicability; description of the wood... CATEGORY Wood Preserving-Boulton Subcategory § 429.90 Applicability; description of the wood preserving... introduction of process wastewater pollutants into a publicly owned treatment works from wood preserving...

7 CFR 160.10 - Sulphate wood turpentine.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or sulphate...

7 CFR 160.10 - Sulphate wood turpentine.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or sulphate...

7 CFR 160.10 - Sulphate wood turpentine.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or sulphate...

40 CFR 429.90 - Applicability; description of the wood preserving-Boulton subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Applicability; description of the wood... CATEGORY Wood Preserving-Boulton Subcategory § 429.90 Applicability; description of the wood preserving... introduction of process wastewater pollutants into a publicly owned treatment works from wood preserving...

40 CFR 429.80 - Applicability; description of the wood preserving-steam subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Applicability; description of the wood... Wood Preserving Steam Subcategory § 429.80 Applicability; description of the wood preserving—steam... process wastewater pollutants into publicly owned treatment works from wood preserving processes that use...

40 CFR 429.80 - Applicability; description of the wood preserving-steam subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Applicability; description of the wood... Wood Preserving Steam Subcategory § 429.80 Applicability; description of the wood preserving—steam... process wastewater pollutants into publicly owned treatment works from wood preserving processes that use...

The Carbon Impacts of Wood Products

Treesearch

Richard Bergman; Maureen Puettmann; Adam Taylor; Kenneth E. Skog

2014-01-01

Wood products have many environmental advantages over nonwood alternatives. Documenting and publicizing these merits helps the future competitiveness of wood when climate change impacts are being considered. The manufacture of wood products requires less fossil fuel than nonwood alternative building materials such as concrete, metals, or plastics. By nature, wood is...

40 CFR 63.2231 - Does this subpart apply to me?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards for Hazardous Air Pollutants: Plywood and Composite Wood Products What This Subpart Covers § 63... manufacturing facility is a facility that manufactures plywood and/or composite wood products by bonding wood... and pressure, to form a structural panel or engineered wood product. Plywood and composite wood...

Wood preservation

Treesearch

Stan T. Lebow

2010-01-01

Many commonly used wood species can deteriorate if exposed to conditions that support growth of wood-degrading organisms (see Chap. 14). Wood products can be protected from the attack of decay fungi, harmful insects, or marine borers by applying chemical preservatives. Preservative treatments greatly increase the life of wood structures, thus reducing replacement costs...

Wood Condition Assessment Manual: Second Edition

Treesearch

Robert J. Ross; Robert H. White

2014-01-01

This report summarizes information on condition assessment of in-service wood, including visual inspection of wood and timbers, use of ultrasound and probing/boring techniques for inspection, and assessment of wood and timbers that have been exposed to fire. The report also includes information on assigning allowable design values for in-service wood.

Finishing of wood

Treesearch

R. Sam Williams

1999-01-01

The primary function of any wood finish (paint, varnish, and stain, for example) is to protect the wood surface, help maintain a certain appearance, and provide a cleanable surface. Although wood can be used both outdoors and indoors without finishing, unfinished wood surfaces exposed to the weather change color, are roughened by photodegradation and surface checking,...

40 CFR 429.90 - Applicability; description of the wood preserving-Boulton subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the wood... Wood Preserving-Boulton Subcategory § 429.90 Applicability; description of the wood preserving—Boulton... process wastewater pollutants into a publicly owned treatment works from wood preserving operations which...

7 CFR 160.10 - Sulphate wood turpentine.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or sulphate...

40 CFR 429.90 - Applicability; description of the wood preserving-Boulton subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the wood... Wood Preserving-Boulton Subcategory § 429.90 Applicability; description of the wood preserving—Boulton... process wastewater pollutants into a publicly owned treatment works from wood preserving operations which...

7 CFR 160.10 - Sulphate wood turpentine.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or sulphate...

Juvenile wood effect in red alder : analysis of physical and mechanical data to delineate juvenile and mature wood zones

Treesearch

Joel W. Evans; John F. Senft; David W. Green

2000-01-01

The objective of this study was to investigate the influence of juvenile wood on the mechanical and physical properties of red alder. Tree growth in the first 10 to 20 years, usually referred to as juvenile wood, often influences wood quality by adversely affecting mechanical strength properties. Strength can be reduced up to 50 percent by the presence of juvenile wood...

Comparison of Wood Preservatives in Stake Tests (1981 Progress Report).

DTIC Science & Technology

1981-12-01

infected with Trichoderma mold, plus other selected species such as oak, Douglas-fir, and Engelmann spruce. Southern pine untreated control stakes...acetylated wood, cyanoethylated wood, that with thiamine destroyed, chemically modified wood, wood infected with Trichoderma mold, embedded fiberboard (western...14 toA4 41U(4 a ...- 44- Table 31.--Condition of southern pine stakes (2 x 4 in. nominal x 18 in.) of uninfected and Trichoderma mcid-infected wood

Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance.

PubMed

Li, Yuanyuan; Fu, Qiliang; Yu, Shun; Yan, Min; Berglund, Lars

2016-04-11

Optically transparent wood (TW) with transmittance as high as 85% and haze of 71% was obtained using a delignified nanoporous wood template. The template was prepared by removing the light-absorbing lignin component, creating nanoporosity in the wood cell wall. Transparent wood was prepared by successful impregnation of lumen and the nanoscale cellulose fiber network in the cell wall with refractive-index-matched prepolymerized methyl methacrylate (MMA). During the process, the hierarchical wood structure was preserved. Optical properties of TW are tunable by changing the cellulose volume fraction. The synergy between wood and PMMA was observed for mechanical properties. Lightweight and strong transparent wood is a potential candidate for lightweight low-cost, light-transmitting buildings and transparent solar cell windows.

Wood energy-commercial applications

NASA Technical Reports Server (NTRS)

Kennel, R. P.

1978-01-01

Wood energy is being widely investigated in many areas of the country because of the many obvious benefits of wood fuel such as the low price per million Btus relative to coal, oil, and gas; the wide availability of noncommercial wood and the proven ability to harvest it; established technology which is reliable and free of pollution; renewable resources; better conservation for harvested land; and the potential for jobs creation. The Southeastern United States has a specific leadership role in wood energy based on its established forest products industry experience and the potential application of wood energy to other industries and institutions. Significant questions about the widespread usage of wood energy are being answered in demonstrations around the country as well as the Southeast in areas of wood storage and bulk handling; high capitalization costs for harvesting and combustion equipment; long term supply and demand contracts; and the economic feasibility of wood energy outside the forest products industry.

Not Just Lumber—Using Wood in the Sustainable Future of Materials, Chemicals, and Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jakes, Joseph E.; Arzola, Xavier; Bergman, Rick

Forest-derived biomaterials can play an integral role in a sustainable and renewable future. Research across a range of disciplines is required to develop the knowledge necessary to overcome the challenges of incorporating more renewable forest resources in materials, chemicals, and fuels. We focus on wood specifically because in our view, better characterization of wood as a raw material and as a feedstock will lead to its increased utilization. We first give an overview of wood structure and chemical composition and then highlight current topics in forest products research, including (1) industrial chemicals, biofuels, and energy from woody materials; (2) wood-basedmore » activated carbon and carbon nanostructures; (3) development of improved wood protection treatments; (4) massive timber construction; (5) wood as a bioinspiring material; and (6) atomic simulations of wood polymers. We conclude with a discussion of the sustainability of wood as a renewable forest resource.« less

Not Just Lumber—Using Wood in the Sustainable Future of Materials, Chemicals, and Fuels

NASA Astrophysics Data System (ADS)

Jakes, Joseph E.; Arzola, Xavier; Bergman, Rick; Ciesielski, Peter; Hunt, Christopher G.; Rahbar, Nima; Tshabalala, Mandla; Wiedenhoeft, Alex C.; Zelinka, Samuel L.

2016-09-01

Forest-derived biomaterials can play an integral role in a sustainable and renewable future. Research across a range of disciplines is required to develop the knowledge necessary to overcome the challenges of incorporating more renewable forest resources in materials, chemicals, and fuels. We focus on wood specifically because in our view, better characterization of wood as a raw material and as a feedstock will lead to its increased utilization. We first give an overview of wood structure and chemical composition and then highlight current topics in forest products research, including (1) industrial chemicals, biofuels, and energy from woody materials; (2) wood-based activated carbon and carbon nanostructures; (3) development of improved wood protection treatments; (4) massive timber construction; (5) wood as a bioinspiring material; and (6) atomic simulations of wood polymers. We conclude with a discussion of the sustainability of wood as a renewable forest resource.

Wood phenology: from organ-scale processes to terrestrial ecosystem models

NASA Astrophysics Data System (ADS)

Delpierre, Nicolas; Guillemot, Joannès

2016-04-01

In temperate and boreal trees, a dormancy period prevents organ development during adverse climatic conditions. Whereas the phenology of leaves and flowers has received considerable attention, to date, little is known regarding the phenology of other tree organs such as wood, fine roots, fruits and reserve compounds. In this presentation, we review both the role of environmental drivers in determining the phenology of wood and the models used to predict its phenology in temperate and boreal forest trees. Temperature is a key driver of the resumption of wood activity in spring. There is no such clear dominant environmental cue involved in the cessation of wood formation in autumn, but temperature and water stress appear as prominent factors. We show that wood phenology is a key driver of the interannual variability of wood growth in temperate tree species. Incorporating representations of wood phenology in a terrestrial ecosystem model substantially improved the simulation of wood growth under current climate.

Wood typification by Venturi easy ambient sonic spray ionization mass spectrometry: the case of the endangered Mahogany tree.

PubMed

Cabral, Elaine C; Simas, Rosineide C; Santos, Vanessa G; Queiroga, Carmen L; da Cunha, Valnei S; de Sá, Gilberto F; Daroda, Romeu J; Eberlin, Marcos N

2012-01-01

Venturi easy ambient sonic spray ionization mass spectrometry in both its liquid (V(L) -EASI-MS) and solid sample modes (V(S) -EASI-MS) is shown to provide nearly immediate and secure typification of woods, as demonstrated for Mahogany, an endangered and most valuable type of tropical wood. This reddish wood displays unique phytochemical markers (phragmalin-type limonoids) which are rapidly detected from the wood surface by V(S) -EASI-MS or from a simple methanol extract of a tiny wood chip by V(L) -EASI-MS. Unique profiles were obtained for Mahogany (Swietenia macrophylla) whereas genuine samples of six other similar types of woods, which are commonly falsified by artificial coloring and commercialized as Mahogany, display also typical but dissimilar pythochemical profiles as compared to that of the authentic wood. Variable and atypical chemical profiles were observed for artificially colored woods. Secure chemical characterization via V(S) -EASI-MS or V(s) -EASI-MS fingerprints of Mahogany and other types of woods with similar appearance should help to control the illegal logging and trade of this and other endangered woods and their falsification, and to create certified standards. Copyright © 2012 John Wiley & Sons, Ltd.

Where Does Wood Most Effectively Enhance Storage? Network-Scale Distribution of Sediment and Organic Matter Stored by Instream Wood

NASA Astrophysics Data System (ADS)

Pfeiffer, Andrew; Wohl, Ellen

2018-01-01

We used 48 reach-scale measurements of large wood and wood-associated sediment and coarse particulate organic matter (CPOM) storage within an 80 km2 catchment to examine spatial patterns of storage relative to stream order. Wood, sediment, and CPOM are not distributed uniformly across the drainage basin. Third- and fourth-order streams (23% of total stream length) disproportionately store wood and coarse and fine sediments: 55% of total wood volume, 78% of coarse sediment, and 49% of fine sediment, respectively. Fourth-order streams store 0.8 m3 of coarse sediment and 0.2 m3 of fine sediment per cubic meter of wood. CPOM storage is highest in first-order streams (60% of storage in 47% of total network stream length). First-order streams can store up to 0.3 m3 of CPOM for each cubic meter of wood. Logjams in third- and fourth-order reaches are primary sediment storage agents, whereas roots in small streams may be more important for storage of CPOM. We propose the large wood particulate storage index to quantify average volume of sediment or CPOM stored by a cubic meter of wood.

Interactions between soil- and dead wood-inhabiting fungal communities during the decay of Norway spruce logs

PubMed Central

Mäkipää, Raisa; Rajala, Tiina; Schigel, Dmitry; Rinne, Katja T; Pennanen, Taina; Abrego, Nerea; Ovaskainen, Otso

2017-01-01

We investigated the interaction between fungal communities of soil and dead wood substrates. For this, we applied molecular species identification and stable isotope tracking to both soil and decaying wood in an unmanaged boreal Norway spruce-dominated stand. Altogether, we recorded 1990 operational taxonomic units, out of which more than 600 were shared by both substrates and 589 were found to exclusively inhabit wood. On average the soil was more species-rich than the decaying wood, but the species richness in dead wood increased monotonically along the decay gradient, reaching the same species richness and community composition as soil in the late stages. Decaying logs at all decay stages locally influenced the fungal communities from soil, some fungal species occurring in soil only under decaying wood. Stable isotope analyses suggest that mycorrhizal species colonising dead wood in the late decay stages actively transfer nitrogen and carbon between soil and host plants. Most importantly, Piloderma sphaerosporum and Tylospora sp. mycorrhizal species were highly abundant in decayed wood. Soil- and wood-inhabiting fungal communities interact at all decay phases of wood that has important implications in fungal community dynamics and thus nutrient transportation. PMID:28430188

Effects of Heat-Treated Wood Particles on the Physico-Mechanical Properties and Extended Creep Behavior of Wood/Recycled-HDPE Composites Using the Time-Temperature Superposition Principle.

PubMed

Yang, Teng-Chun; Chien, Yi-Chi; Wu, Tung-Lin; Hung, Ke-Chang; Wu, Jyh-Horng

2017-03-30

This study investigated the effectiveness of heat-treated wood particles for improving the physico-mechanical properties and creep performance of wood/recycled-HDPE composites. The results reveal that the composites with heat-treated wood particles had significantly decreased moisture content, water absorption, and thickness swelling, while no improvements of the flexural properties or the wood screw holding strength were observed, except for the internal bond strength. Additionally, creep tests were conducted at a series of elevated temperatures using the time-temperature superposition principle (TTSP), and the TTSP-predicted creep compliance curves fit well with the experimental data. The creep resistance values of composites with heat-treated wood particles were greater than those having untreated wood particles due to the hydrophobic character of the treated wood particles and improved interfacial compatibility between the wood particles and polymer matrix. At a reference temperature of 20 °C, the improvement of creep resistance ( ICR ) of composites with heat-treated wood particles reached approximately 30% over a 30-year period, and it increased significantly with increasing reference temperature.

Effects of Heat-Treated Wood Particles on the Physico-Mechanical Properties and Extended Creep Behavior of Wood/Recycled-HDPE Composites Using the Time–Temperature Superposition Principle

PubMed Central

Yang, Teng-Chun; Chien, Yi-Chi; Wu, Tung-Lin; Hung, Ke-Chang; Wu, Jyh-Horng

2017-01-01

This study investigated the effectiveness of heat-treated wood particles for improving the physico-mechanical properties and creep performance of wood/recycled-HDPE composites. The results reveal that the composites with heat-treated wood particles had significantly decreased moisture content, water absorption, and thickness swelling, while no improvements of the flexural properties or the wood screw holding strength were observed, except for the internal bond strength. Additionally, creep tests were conducted at a series of elevated temperatures using the time–temperature superposition principle (TTSP), and the TTSP-predicted creep compliance curves fit well with the experimental data. The creep resistance values of composites with heat-treated wood particles were greater than those having untreated wood particles due to the hydrophobic character of the treated wood particles and improved interfacial compatibility between the wood particles and polymer matrix. At a reference temperature of 20 °C, the improvement of creep resistance (ICR) of composites with heat-treated wood particles reached approximately 30% over a 30-year period, and it increased significantly with increasing reference temperature. PMID:28772726

Microbial Communities in Sunken Wood Are Structured by Wood-Boring Bivalves and Location in a Submarine Canyon

PubMed Central

Fagervold, Sonja K.; Romano, Chiara; Kalenitchenko, Dimitri; Borowski, Christian; Nunes-Jorge, Amandine; Martin, Daniel; Galand, Pierre E.

2014-01-01

The cornerstones of sunken wood ecosystems are microorganisms involved in cellulose degradation. These can either be free-living microorganisms in the wood matrix or symbiotic bacteria associated with wood-boring bivalves such as emblematic species of Xylophaga, the most common deep-sea woodborer. Here we use experimentally submerged pine wood, placed in and outside the Mediterranean submarine Blanes Canyon, to compare the microbial communities on the wood, in fecal pellets of Xylophaga spp. and associated with the gills of these animals. Analyses based on tag pyrosequencing of the 16S rRNA bacterial gene showed that sunken wood contained three distinct microbial communities. Wood and pellet communities were different from each other suggesting that Xylophaga spp. create new microbial niches by excreting fecal pellets into their burrows. In turn, gills of Xylophaga spp. contain potential bacterial symbionts, as illustrated by the presence of sequences closely related to symbiotic bacteria found in other wood eating marine invertebrates. Finally, we found that sunken wood communities inside the canyon were different and more diverse than the ones outside the canyon. This finding extends to the microbial world the view that submarine canyons are sites of diverse marine life. PMID:24805961

Microbial communities in sunken wood are structured by wood-boring bivalves and location in a submarine canyon.

PubMed

Fagervold, Sonja K; Romano, Chiara; Kalenitchenko, Dimitri; Borowski, Christian; Nunes-Jorge, Amandine; Martin, Daniel; Galand, Pierre E

2014-01-01

The cornerstones of sunken wood ecosystems are microorganisms involved in cellulose degradation. These can either be free-living microorganisms in the wood matrix or symbiotic bacteria associated with wood-boring bivalves such as emblematic species of Xylophaga, the most common deep-sea woodborer. Here we use experimentally submerged pine wood, placed in and outside the Mediterranean submarine Blanes Canyon, to compare the microbial communities on the wood, in fecal pellets of Xylophaga spp. and associated with the gills of these animals. Analyses based on tag pyrosequencing of the 16S rRNA bacterial gene showed that sunken wood contained three distinct microbial communities. Wood and pellet communities were different from each other suggesting that Xylophaga spp. create new microbial niches by excreting fecal pellets into their burrows. In turn, gills of Xylophaga spp. contain potential bacterial symbionts, as illustrated by the presence of sequences closely related to symbiotic bacteria found in other wood eating marine invertebrates. Finally, we found that sunken wood communities inside the canyon were different and more diverse than the ones outside the canyon. This finding extends to the microbial world the view that submarine canyons are sites of diverse marine life.

The pulse of driftwood export from a very large forested river basin over multiple time scales, Slave River, Canada

NASA Astrophysics Data System (ADS)

Kramer, Natalie; Wohl, Ellen; Hess-Homeier, Brooke; Leisz, Stephen

2017-03-01

This study presents a case study of large wood transport on the great Slave River in northern Canada with the objective to better understand the processes of and variability in pulsed wood fluxes from large forested catchments. We use a varied approach, integrating field characterization of wood, historical anecdotes, repeat aerial imagery of stored wood, and time-lapse imagery of moving wood, for a robust analysis and synthesis of processes behind pulsed wood flux, from yearly uncongested export to rare congested wood floods. Repeat monitoring of known sites of temporary storage with new or historic imagery proved to be a very useful tool for constraining wood flux histories. Pulsed wood export on the Slave River is not an artifact of episodic recruitment from major up-basin disturbances, but rather reflects decadal- to half-century-scale discharge patterns that redistribute wood recruited from channel migration and bank slumping. We suggest that the multiyear flow history is of paramount importance for estimating wood flux magnitude, followed in declining importance by the yearly sequence of peaks and the magnitude and characteristics of the rising limb of individual floods.

Interactions between soil- and dead wood-inhabiting fungal communities during the decay of Norway spruce logs.

PubMed

Mäkipää, Raisa; Rajala, Tiina; Schigel, Dmitry; Rinne, Katja T; Pennanen, Taina; Abrego, Nerea; Ovaskainen, Otso

2017-09-01

We investigated the interaction between fungal communities of soil and dead wood substrates. For this, we applied molecular species identification and stable isotope tracking to both soil and decaying wood in an unmanaged boreal Norway spruce-dominated stand. Altogether, we recorded 1990 operational taxonomic units, out of which more than 600 were shared by both substrates and 589 were found to exclusively inhabit wood. On average the soil was more species-rich than the decaying wood, but the species richness in dead wood increased monotonically along the decay gradient, reaching the same species richness and community composition as soil in the late stages. Decaying logs at all decay stages locally influenced the fungal communities from soil, some fungal species occurring in soil only under decaying wood. Stable isotope analyses suggest that mycorrhizal species colonising dead wood in the late decay stages actively transfer nitrogen and carbon between soil and host plants. Most importantly, Piloderma sphaerosporum and Tylospora sp. mycorrhizal species were highly abundant in decayed wood. Soil- and wood-inhabiting fungal communities interact at all decay phases of wood that has important implications in fungal community dynamics and thus nutrient transportation.

Health effects of residential wood smoke particles: the importance of combustion conditions and physicochemical particle properties

PubMed Central

Kocbach Bølling, Anette; Pagels, Joakim; Yttri, Karl Espen; Barregard, Lars; Sallsten, Gerd; Schwarze, Per E; Boman, Christoffer

2009-01-01

Background Residential wood combustion is now recognized as a major particle source in many developed countries, and the number of studies investigating the negative health effects associated with wood smoke exposure is currently increasing. The combustion appliances in use today provide highly variable combustion conditions resulting in large variations in the physicochemical characteristics of the emitted particles. These differences in physicochemical properties are likely to influence the biological effects induced by the wood smoke particles. Outline The focus of this review is to discuss the present knowledge on physicochemical properties of wood smoke particles from different combustion conditions in relation to wood smoke-induced health effects. In addition, the human wood smoke exposure in developed countries is explored in order to identify the particle characteristics that are relevant for experimental studies of wood smoke-induced health effects. Finally, recent experimental studies regarding wood smoke exposure are discussed with respect to the applied combustion conditions and particle properties. Conclusion Overall, the reviewed literature regarding the physicochemical properties of wood smoke particles provides a relatively clear picture of how these properties vary with the combustion conditions, whereas particle emissions from specific classes of combustion appliances are less well characterised. The major gaps in knowledge concern; (i) characterisation of the atmospheric transformations of wood smoke particles, (ii) characterisation of the physicochemical properties of wood smoke particles in ambient and indoor environments, and (iii) identification of the physicochemical properties that influence the biological effects of wood smoke particles. PMID:19891791

Thermochemical Modeling and Experimental Validation of Wood Pyrolysis Occurring During Pre-ignition Combustion

NASA Astrophysics Data System (ADS)

Fawaz, M.; Lautenberger, C.; Bond, T. C.

2017-12-01

The use of wood as a solid fuel for cooking and heating is associated with high particle emission which largely contribute to the dispersion of particulate matter (PM) in the atmosphere. The majority of those particles are released during the "pre-ignition" phase, i.e., before flaming of the wood occurs. In this work, we investigate the factors that influence the emission of PM during pre-ignition and lead to high particle emission to the atmosphere. During this combustion phase, at elevated temperature, pyrolysis is responsible for wood degradation and the production of gaseous materials that travel and exit the wood. We model the thermal degradation using Gpyro, an open source finite volume method numerical model to simulate heat, mass, and momentum transfer in the wood. In our analysis, we study factors that vary during combustion and that influence emission of PM: wood sample size and boundary conditions. In a fire the boundary conditions represent the thermal energy a piece of wood receives from the surrounding in the form of heat flux. We find that heat transfer is the limiting process governing the production and transport of gas from the wood, and that the amount of emitted PM is dependent on the size of the wood. The dependence of heat transfer from the boundaries on PM emission becomes more important with increasing wood log size. The model shows that a small log of wood (6cm by 2cm) emits close values of total mass of gas at low and high heat fluxes. For a large log of wood (20cm by 5cm) the total mass of gas emitted increases by 30% between low and high heat flux. We validate the model results with a controlled-temperature reactor that accommodates centimeter scale wood samples. The size of the wood used, indicates the abundance of wood in the region where wood is used a solid fuel. Understanding those factors will allow for defining conditions that result in reducing particle emissions during combustion.

Factors controlling large-wood transport in a mountain river

NASA Astrophysics Data System (ADS)

Ruiz-Villanueva, Virginia; Wyżga, Bartłomiej; Zawiejska, Joanna; Hajdukiewicz, Maciej; Stoffel, Markus

2016-11-01

As with bedload transport, wood transport in rivers is governed by several factors such as flow regime, geomorphic configuration of the channel and floodplain, or wood size and shape. Because large-wood tends to be transported during floods, safety and logistical constraints make field measurements difficult. As a result, direct observation and measurements of the conditions of wood transport are scarce. This lack of direct observations and the complexity of the processes involved in wood transport may result in an incomplete understanding of wood transport processes. Numerical modelling provides an alternative approach to addressing some of the unknowns in the dynamics of large-wood in rivers. The aim of this study is to improve the understanding of controls governing wood transport in mountain rivers, combining numerical modelling and direct field observations. By defining different scenarios, we illustrate relationships between the rate of wood transport and discharge, wood size, and river morphology. We test these relationships for a wide, multithread reach and a narrower, partially channelized single-thread reach of the Czarny Dunajec River in the Polish Carpathians. Results indicate that a wide range of quantitative information about wood transport can be obtained from a combination of numerical modelling and field observations and from document contrasting patterns of wood transport in single- and multithread river reaches. On the one hand, log diameter seems to have a greater importance for wood transport in the multithread channel because of shallower flow, lower flow velocity, and lower stream power. Hydrodynamic conditions in the single-thread channel allow transport of large-wood pieces, whereas in the multithread reach, logs with diameters similar to water depth are not being moved. On the other hand, log length also exerts strong control on wood transport, more so in the single-thread than in the multithread reach. In any case, wood transport strongly decreases with increasing piece volume, although this relation is not linear. We also document a nonlinear relationship between wood transport and flood magnitude. A threshold discharge was identified below which wood transport is negligible. This threshold is higher in the multithread reach, while in the single-thread reach floods of lower magnitude are able to transport wood downstream. Wood transport ratio increases with discharge until it reaches an upper threshold or tipping point, and then decreases or increases much more slowly. This threshold is clearly related to bankfull discharge, but it is much higher for the multithread reach than for the single-thread one. Although modelling input and field observations were taken from a specific river, our findings and conclusions are likely to be applicable to a much larger suite of (mountain) rivers.

Bridging the gaps: An overview of wood across time and space in diverse rivers

NASA Astrophysics Data System (ADS)

Wohl, Ellen

2017-02-01

Nearly 50 years of research focused on large wood (LW) in rivers provide a basis for understanding how wood enters rivers; how wood decays, breaks, and is transported downstream; and how at least temporarily stable wood influences channel geometry, fluxes of water, sediment, and organic matter, and the abundance and diversity of aquatic and riparian organisms. Field-based studies have led to qualitative conceptual models and to numerical stimulations of river processes involving wood. Numerous important gaps remain, however, in our understanding of wood dynamics. The majority of research on wood in rivers focuses on small- to medium-sized rivers, defined using the ratio of wood piece size to channel width as channels narrower than the locally typical wood-piece length (small) and slightly narrower than the longer wood pieces present (medium). Although diverse geographic regions and biomes are represented by one or a few studies in each region, the majority of research comes from perennial rivers draining temperate conifer forests. Regional syntheses most commonly focus on the Pacific Northwest region of North America where most of these studies originate. Consequently, significant gaps in our understanding include lack of knowledge of wood-related processes in large rivers, dryland rivers, and rivers of the high and low latitudes. Using a wood budget as an organizing framework, this paper identifies other gaps related to wood recruitment, transport, storage, and how beavers influence LW dynamics. With respect to wood recruitment, we lack information on the relative importance of mass tree mortality and transport of buried or surficial downed wood from the floodplain into the channel in diverse settings. Knowledge gaps related to wood transport include transport distances of LW and thresholds for LW mobility in small to medium rivers. With respect to wood storage, we have limited data on longitudinal trends in LW loads within unaltered large and great rivers and on fluctuations in LW load over time intervals greater than a few years. Other knowledge gaps relate to physical and ecological effects of wood, including the magnitude of flow resistance caused by LW; patterns of wood-related sediment storage for diverse river sizes and channel geometry; quantification of channel-floodplain-LW interactions; and potential threshold effects of LW in relation to physical processes and biotic communities. Finally, knowledge gaps are related to management of large wood and river corridors, including understanding the consequences of enormous historical reductions in LW load in rivers through the forested portions of the temperate zone; and how to effectively reintroduce and manage existing LW in river corridors, which includes enhancing public understanding of the importance of LW. Addressing these knowledge gaps requires more case studies from diverse rivers, as well as more syntheses and metadata analyses.

A foundation monograph of Convolvulus L. (Convolvulaceae).

PubMed

Wood, John R I; Williams, Bethany R M; Mitchell, Thomas C; Carine, Mark A; Harris, David J; Scotland, Robert W

2015-01-01

A global revision of Convolvulus L. is presented, Calystegia R.Br. being excluded on pragmatic grounds. One hundred and ninety species are recognised with the greatest diversity in the Irano-Turanian region. All recognised species are described and the majority are illustrated. Distribution details, keys to species identification and taxonomic notes are provided. Four new species, Convolvulusaustroafricanus J.R.I.Wood & R.W.Scotland, sp. nov., Convolvulusiranicus J.R.I.Wood & R.W.Scotland, sp. nov., Convolvuluspeninsularis J.R.I.Wood & R.W.Scotland, sp. nov. and Convolvulusxanthopotamicus J.R.I.Wood & R.W.Scotland, sp. nov., one new subspecies Convolvuluschinensissubsp.triangularis J.R.I.Wood & R.W.Scotland, subsp. nov., and two new varieties Convolvulusequitansvar.lindheimeri J.R.I.Wood & R.W.Scotland, var. nov., Convolvulusglomeratusvar.sachalitarum J.R.I.Wood & R.W.Scotland, var. nov. are described. Convolvulusincisodentatus J.R.I.Wood & R.W.Scotland, nom. nov., is provided as a replacement name for the illegitimate Convolvulusincisus Choisy. Several species treated as synonyms of other species in recent publications are reinstated including Convolvuluschinensis Ker-Gawl., Convolvulusspinifer M.Popov., Convolvulusrandii Rendle and Convolvulusaschersonii Engl. Ten taxa are given new status and recognised at new ranks: Convolvulusnamaquensis (Schltr. ex. A.Meeuse) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulushermanniaesubsp.erosus (Desr.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvuluscrenatifoliussubsp.montevidensis (Spreng.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulusfruticulosussubsp.glandulosus (Webb) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvuluscapituliferussubsp.foliaceus (Verdc.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulushystrixsubsp.ruspolii (Dammer ex Hallier f.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulushystrixsubsp.inermis (Chiov.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulusrottlerianussubsp.stocksii (Boiss.) J.R.I.Wood & R.W.Scotland, comb. et stat. nov., Convolvuluscalvertiisubsp.ruprechtii (Boiss.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvuluscephalopodussubsp.bushiricus (Bornm.) J.R.I.Wood & R.W.Scotland, stat. nov. The status of various infraspecific taxa is clarified and numerous taxa are lectotypified. This account represents a new initiative in terms of taxonomic monography, being an attempt to bring together the global approach of the traditional monograph with the more pragmatic and identification-focussed approach of most current floras while at the same time being informed by insights from molecular systematics.

LCA-based optimization of wood utilization under special consideration of a cascading use of wood.

PubMed

Höglmeier, Karin; Steubing, Bernhard; Weber-Blaschke, Gabriele; Richter, Klaus

2015-04-01

Cascading, the use of the same unit of a resource in multiple successional applications, is considered as a viable means to improve the efficiency of resource utilization and to decrease environmental impacts. Wood, as a regrowing but nevertheless limited and increasingly in demand resource, can be used in cascades, thereby increasing the potential efficiency per unit of wood. This study aims to assess the influence of cascading wood utilization on optimizing the overall environmental impact of wood utilization. By combining a material flow model of existing wood applications - both for materials provision and energy production - with an algebraic optimization tool, the effects of the use of wood in cascades can be modelled and quantified based on life cycle impact assessment results for all production processes. To identify the most efficient wood allocation, the effects of a potential substitution of non-wood products were taken into account in a part of the model runs. The considered environmental indicators were global warming potential, particulate matter formation, land occupation and an aggregated single score indicator. We found that optimizing either the overall global warming potential or the value of the single score indicator of the system leads to a simultaneous relative decrease of all other considered environmental impacts. The relative differences between the impacts of the model run with and without the possibility of a cascading use of wood were 7% for global warming potential and the single score indicator, despite cascading only influencing a small part of the overall system, namely wood panel production. Cascading led to savings of up to 14% of the annual primary wood supply of the study area. We conclude that cascading can improve the overall performance of a wood utilization system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Wood Stove Pollution in the Developed World: A Case to Raise Awareness Among Pediatricians.

PubMed

Rokoff, Lisa B; Koutrakis, Petros; Garshick, Eric; Karagas, Margaret R; Oken, Emily; Gold, Diane R; Fleisch, Abby F

2017-06-01

Use of wood for residential heating is regaining popularity in developed countries. Currently, over 11 million US homes are heated with a wood stove. Although wood stoves reduce heating costs, wood smoke may adversely impact child health through the emission of gaseous and particulate air pollutants. Our purpose is to raise awareness of this environmental health issue among pediatricians. To summarize the state of the science, we performed a narrative review of articles published in PubMed and Web of Science. We identified 36 studies in developed countries that reported associations of household wood stove use and/or community wood smoke exposure with pediatric health outcomes. Studies primarily investigated respiratory outcomes, with no evaluation of cardiometabolic or neurocognitive health. Studies found community wood smoke exposure to be consistently associated with adverse pediatric respiratory health. Household wood stove use was less consistently associated with respiratory outcomes. However, studies of household wood stoves always relied on participant self-report of wood stove use, while studies of community wood smoke generally assessed air pollution exposure directly and more precisely in larger study populations. In most studies, important potential confounders, such as markers of socioeconomic status, were unaccounted for and may have biased results. We conclude that studies with improved exposure assessment, that measure and account for confounding, and that consider non-respiratory outcomes are needed. While awaiting additional data, pediatricians can refer patients to precautionary measures recommended by the US Environmental Protection Agency (EPA) to mitigate exposure. These include replacing old appliances with EPA-certified stoves, properly maintaining the stove, and using only dry, well-seasoned wood. In addition, several studies have shown mechanical air filters to effectively reduce wood stove pollution exposure in affected homes and communities. Copyright © 2017 Mosby, Inc. All rights reserved.

Wood Stove Pollution in the Developed World: A Case to Raise Awareness Among Pediatricians

PubMed Central

Rokoff, Lisa B.; Koutrakis, Petros; Garshick, Eric; Karagas, Margaret R.; Oken, Emily; Gold, Diane R.; Fleisch, Abby F.

2017-01-01

Use of wood for residential heating is regaining popularity in developed countries. Currently, over 11 million US homes are heated with a wood stove. Although wood stoves reduce heating costs, wood smoke may adversely impact child health through the emission of gaseous and particulate air pollutants. Our purpose is to raise awareness of this environmental health issue among pediatricians. To summarize the state of the science, we performed a narrative review of articles published in PubMed and Web of Science. We identified 36 studies in developed countries that reported associations of household wood stove use and/or community wood smoke exposure with pediatric health outcomes. Studies primarily investigated respiratory outcomes, with no evaluation of cardiometabolic or neurocognitive health. Studies found community wood smoke exposure to be consistently associated with adverse pediatric respiratory health. Household wood stove use was less consistently associated with respiratory outcomes. However, studies of household wood stoves always relied on participant self-report of wood stove use, while studies of community wood smoke generally assessed air pollution exposure directly and more precisely in larger study populations. In most studies, important potential confounders, such as markers of socioeconomic status, were unaccounted for and may have biased results. We conclude that studies with improved exposure assessment, that measure and account for confounding, and that consider non-respiratory outcomes are needed. While awaiting additional data, pediatricians can refer patients to precautionary measures recommended by the US Environmental Protection Agency (EPA) to mitigate exposure. These include replacing old appliances with EPA-certified stoves, properly maintaining the stove, and using only dry, well-seasoned wood. In addition, several studies have shown mechanical air filters to effectively reduce wood stove pollution exposure in affected homes and communities. PMID:28583817

Cellulose and lignin biosynthesis is altered by ozone in wood of hybrid poplar (Populus tremula×alba)

PubMed Central

Richet, Nicolas; Afif, Dany; Huber, Françoise; Pollet, Brigitte; Banvoy, Jacques; El Zein, Rana; Lapierre, Catherine; Dizengremel, Pierre; Perré, Patrick; Cabané, Mireille

2011-01-01

Wood formation in trees is a dynamic process that is strongly affected by environmental factors. However, the impact of ozone on wood is poorly documented. The objective of this study was to assess the effects of ozone on wood formation by focusing on the two major wood components, cellulose and lignin, and analysing any anatomical modifications. Young hybrid poplars (Populus tremula×alba) were cultivated under different ozone concentrations (50, 100, 200, and 300 nl l−1). As upright poplars usually develop tension wood in a non-set pattern, the trees were bent in order to induce tension wood formation on the upper side of the stem and normal or opposite wood on the lower side. Biosynthesis of cellulose and lignin (enzymes and RNA levels), together with cambial growth, decreased in response to ozone exposure. The cellulose to lignin ratio was reduced, suggesting that cellulose biosynthesis was more affected than that of lignin. Tension wood was generally more altered than opposite wood, especially at the anatomical level. Tension wood may be more susceptible to reduced carbon allocation to the stems under ozone exposure. These results suggested a coordinated regulation of cellulose and lignin deposition to sustain mechanical strength under ozone. The modifications of the cellulose to lignin ratio and wood anatomy could allow the tree to maintain radial growth while minimizing carbon cost. PMID:21357770

Detection and Identification of Decay Fungi in Spruce Wood by Restriction Fragment Length Polymorphism Analysis of Amplified Genes Encoding rRNA†

PubMed Central

Jasalavich, Claudia A.; Ostrofsky, Andrea; Jellison, Jody

2000-01-01

We have developed a DNA-based assay to reliably detect brown rot and white rot fungi in wood at different stages of decay. DNA, isolated by a series of CTAB (cetyltrimethylammonium bromide) and organic extractions, was amplified by the PCR using published universal primers and basidiomycete-specific primers derived from ribosomal DNA sequences. We surveyed 14 species of wood-decaying basidiomycetes (brown-rot and white-rot fungi), as well as 25 species of wood-inhabiting ascomycetes (pathogens, endophytes, and saprophytes). DNA was isolated from pure cultures of these fungi and also from spruce wood blocks colonized by individual isolates of wood decay basidiomycetes or wood-inhabiting ascomycetes. The primer pair ITS1-F (specific for higher fungi) and ITS4 (universal primer) amplified the internal transcribed spacer region from both ascomycetes and basidiomycetes from both pure culture and wood, as expected. The primer pair ITS1-F (specific for higher fungi) and ITS4-B (specific for basidiomycetes) was shown to reliably detect the presence of wood decay basidiomycetes in both pure culture and wood; ascomycetes were not detected by this primer pair. We detected the presence of decay fungi in wood by PCR before measurable weight loss had occurred to the wood. Basidiomycetes were identified to the species level by restriction fragment length polymorphisms of the internal transcribed spacer region. PMID:11055916

Experimental analysis and simulation modeling of forest management impacts on wood thrushes, Hylocichla mustelina

USGS Publications Warehouse

Banks, R.C.

1998-01-01

North American Breeding Bird Survey data show that wood thrush (Hylocichla mustelina) populations in eastern U.S. forests have declined 1.8% per year during 1966-95. The declining quality of breeding forest tracts in North America is one possible cause for the apparent decline of some neotropical migratory birds, such as the wood thrush. In Georgia, however, wood thrush populations have declined during a period of increasing pine forest area and larger patch sizes. We hypothesized that forest management practices such as thinning and prescribed burning might create unsuitable habitat for wood thrushes. We conducted a four-year before/after, treatment/control experiment at the Piedmont National Wildlife Refuge in central Georgia to study to the effects of a treatment of thinning and prescribed burning on wood thrush demographic parameters. We simultaneously monitored wood thrush adults and juveniles with mark-recapture, radio-telemetry, nest searches, and plot-map surveys. Our analyses showed that wood thrushes were less likely to emigrate from the study compartments after the treatment, and wood thrushes exhibited some tendency to increase preference for hardwood habitats and decrease preference for pine habitats following the treatment. However, we observed no effects of treatment on nest success, adult survival, and adult and juvenile dispersal distances. We also found that female wood thrushes had lower survival rates than males during the breeding season, and we documented large-scale, within-year dispersal movements of adult (up to 17 km) and juvenile (up to 7 km) wood thrushes. We conclude that landscape level habitat quantity and quality must be considered during songbird management decisions. The documentation of sex- and age-specific wood thrush survival and movement rates was critical for construction of a set of population models. We used three stochastic models to learn more about wood thrush population dynamics and make predictions about population growth rates, reproductive success, and the effect of habitat changes on wood thrush populations. The simplest source/sink population model suggests that the Piedmont National Wildlife Refuge's wood thrush population is probably stable or increasing, and wood thrush populations in treated areas had higher growth rates than birds in untreated areas. We were able to use the individual-based model of wood thrush productivity to predict fecundity, a parameter that we could not measure directly in the field. Again, females on treated areas had higher fecundity than birds on untreated areas. Our spatially-based model predicted that wood thrush populations should respond positively to predicted changes in the age/size class structure of the Refuge's pine forests. Our model also showed that most wood thrushes leave the Refuge's forest compartments during the breeding season, and these dispersal movements are extremely important to understanding and managing wood thrush populations. The use of prescribed burning and retention shelterwood silviculture at the Piedmont National Wildlife Refuge does not appear to negatively affect the local wood thrush population. Continued use of the current management regime should result in adequate nesting, foraging, and escape habitats for wood thrushes. However, landscape-level habitat availability and quality, including lands outside the Refuge, must be considered when making management decisions that may affect wood thrushes.

40 CFR 454.30 - Applicability; description of the manufacture of wood rosin, turpentine and pine oil subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... manufacture of wood rosin, turpentine and pine oil subcategory. 454.30 Section 454.30 Protection of... WOOD CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Wood Rosin, Turpentine and Pine Oil Subcategory § 454.30 Applicability; description of the manufacture of wood rosin, turpentine and pine oil...

40 CFR 63.2267 - Initial compliance demonstration for a reconstituted wood product press or board cooler.

Code of Federal Regulations, 2012 CFR

2012-07-01

... reconstituted wood product press or board cooler. 63.2267 Section 63.2267 Protection of Environment... Pollutants: Plywood and Composite Wood Products Initial Compliance Requirements § 63.2267 Initial compliance demonstration for a reconstituted wood product press or board cooler. If you operate a reconstituted wood...

40 CFR 454.30 - Applicability; description of the manufacture of wood rosin, turpentine and pine oil subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... manufacture of wood rosin, turpentine and pine oil subcategory. 454.30 Section 454.30 Protection of... WOOD CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Wood Rosin, Turpentine and Pine Oil Subcategory § 454.30 Applicability; description of the manufacture of wood rosin, turpentine and pine oil...

40 CFR 63.2267 - Initial compliance demonstration for a reconstituted wood product press or board cooler.

Code of Federal Regulations, 2013 CFR

2013-07-01

... reconstituted wood product press or board cooler. 63.2267 Section 63.2267 Protection of Environment... Pollutants: Plywood and Composite Wood Products Initial Compliance Requirements § 63.2267 Initial compliance demonstration for a reconstituted wood product press or board cooler. If you operate a reconstituted wood...

40 CFR 63.2267 - Initial compliance demonstration for a reconstituted wood product press or board cooler.

Code of Federal Regulations, 2014 CFR

2014-07-01

... reconstituted wood product press or board cooler. 63.2267 Section 63.2267 Protection of Environment... Pollutants: Plywood and Composite Wood Products Initial Compliance Requirements § 63.2267 Initial compliance demonstration for a reconstituted wood product press or board cooler. If you operate a reconstituted wood...

40 CFR 454.30 - Applicability; description of the manufacture of wood rosin, turpentine and pine oil subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... manufacture of wood rosin, turpentine and pine oil subcategory. 454.30 Section 454.30 Protection of... WOOD CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Wood Rosin, Turpentine and Pine Oil Subcategory § 454.30 Applicability; description of the manufacture of wood rosin, turpentine and pine oil...

The challenge of bonding treated wood

Treesearch

Charles R. Frihart

2004-01-01

Wood products are quite durable if exposure to moisture is minimized; however, most uses of wood involve considerable exposure to moisture. To preserve the wood, chemicals are used to minimize moisture pickup, to prevent insect attack, and/or to resist microbial growth. The chemicals used as preservatives can interfere with adhesive bonds to wood. Given the many...

Evaluating shrinkage of wood propellers in a high-temperature environment

Treesearch

Richard Bergman; Robert J. Ross

2008-01-01

Minimizing wood shrinkage is a priority for many wood products in use, particularly engineered products manufactured to close tolerances, such as wood propellers for unmanned surveillance aircraft used in military operations. Those currently in service in the Middle East are experiencing performance problems as a consequence of wood shrinking during long-term storage...

49 CFR 178.935 - Standards for wooden Large Packagings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Packagings. (i) Natural wood used in the construction of Large Packagings must be well-seasoned, commercially...) Reconstituted wood used in the construction of Large Packagings must be water resistant reconstituted wood such... Packaging types are designated: (1) 50C natural wood. (2) 50D plywood. (3) 50F reconstituted wood. (b...

Wood and Other Materials Used to Construct Nonresidential Buildings - Canada

Treesearch

David B. McKeever; Joe Elling

2014-01-01

Low-rise nonresidential building construction is an important market in Canada for lumber, engineered wood products, structural wood panels, and nonstructural wood panels. This report examines wood products consumption in 2012 for construction of selected low-rise nonresidential buildings types that have six or fewer stories. Buildings with more than six stories are...

Raman spectroscopic characterization of wood and pulp fibers

Treesearch

Umesh Prasad Agarwal

2008-01-01

This chapter reviews applications of Raman spectroscopy in the field of wood and pulp fibers. Most of the literature examined was published between 1998 and 2006. In addition to introduction, this chapter contains sections on wood and components, mechanical pulp, chemical pulp, modified/treated wood, cellulose I crystallinity of wood fibers, and the self-absorption...

Water repellents and water-repellent preservatives for wood

Treesearch

R. Sam Williams; William C. Feist

1999-01-01

Water repellents and water-repellent preservatives increase the durability of wood by enabling the wood to repel liquid water. This report focuses on water-repellent finishes for wood exposed outdoors above ground. The report includes a discussion of the effects of outdoor exposure on wood, the characteristics of water repellent and water-repellent preservative...

EFFECTS OF BURN RATE, WOOD SPECIES, MOISTURE CONTENT AND WEIGHT OF WOOD LOADED ON WOODSTOVE EMISSIONS

EPA Science Inventory

The report gives results of tests of four woodstove operating parameters (burn rate, wood moisture, wood load, and wood species) at two levels each using a half factorial experimental test design to determine statistically significant effects on the emission components CO, CO2, p...

FIRE INSURANCE AND WOOD SCHOOL BUILDINGS.

ERIC Educational Resources Information Center

PURCELL, FRANK X.

A COMPARISON OF FIRE INSURANCE COSTS OF WOOD, MASONRY, STEEL AND CONCRETE STRUCTURES SHOWS FIRE INSURANCE PREMIMUMS ON WOOD STRUCTURES TEND TO BE HIGHER THAN PREMIUMS ON MASONRY, STEEL AND CONCRETE BUILDINGS, HOWEVER, THE INITIAL COST OF THE WOOD BUILDINGS IS LOWER. DATA SHOW THAT THE SAVINGS ACHIEVED IN THE INITIAL COST OF WOOD STRUCTURES OFFSET…

Wood for energy in the Pacific Northwest: an overview.

Treesearch

James O. Howard

1979-01-01

This report presents an overview of the technology of converting wood to energy and the availability of wood. The first section describes fuel values and significant processes used to generate various energy products from wood. Physical, technical, and economic availability of the wood resource is discussed in the second section. The paper...

40 CFR 430.80 - Applicability; description of the non-wood chemical pulp subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-wood chemical pulp subcategory. 430.80 Section 430.80 Protection of Environment ENVIRONMENTAL... CATEGORY Non-Wood Chemical Pulp Subcategory § 430.80 Applicability; description of the non-wood chemical... production of pulp and paper at non-wood chemical pulp mills. This subcategory includes, but is not limited...

77 FR 71167 - Multilayered Wood Flooring From the People's Republic of China: Notice of Court Decision Not in...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-29

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-971] Multilayered Wood Flooring... public that the final judgment in this case is not in harmony with the Department's Wood Flooring Final... multilayered wood flooring (``wood flooring'') from the People's Republic of China (``PRC'') covering the...

40 CFR 430.80 - Applicability; description of the non-wood chemical pulp subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-wood chemical pulp subcategory. 430.80 Section 430.80 Protection of Environment ENVIRONMENTAL... CATEGORY Non-Wood Chemical Pulp Subcategory § 430.80 Applicability; description of the non-wood chemical... production of pulp and paper at non-wood chemical pulp mills. This subcategory includes, but is not limited...

40 CFR 63.2267 - Initial compliance demonstration for a reconstituted wood product press or board cooler.

Code of Federal Regulations, 2011 CFR

2011-07-01

... reconstituted wood product press or board cooler. 63.2267 Section 63.2267 Protection of Environment... and Composite Wood Products Initial Compliance Requirements § 63.2267 Initial compliance demonstration for a reconstituted wood product press or board cooler. If you operate a reconstituted wood product...

40 CFR 63.2267 - Initial compliance demonstration for a reconstituted wood product press or board cooler.

Code of Federal Regulations, 2010 CFR

2010-07-01

... reconstituted wood product press or board cooler. 63.2267 Section 63.2267 Protection of Environment... and Composite Wood Products Initial Compliance Requirements § 63.2267 Initial compliance demonstration for a reconstituted wood product press or board cooler. If you operate a reconstituted wood product...

49 CFR 178.515 - Standards for reconstituted wood boxes.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for reconstituted wood boxes. 178.515... wood boxes. (a) The identification code for a reconstituted wood box is 4F. (b) Construction requirements for reconstituted wood boxes are as follows: (1) The walls of boxes must be made of water...

Environment-friendly wood fibre composite with high bonding strength and water resistance

PubMed Central

Ji, Xiaodi; Dong, Yue; Nguyen, Tat Thang; Chen, Xueqi

2018-01-01

With the growing depletion of wood-based materials and concerns over emissions of formaldehyde from traditional wood fibre composites, there is a desire for environment-friendly binders. Herein, we report a green wood fibre composite with specific bonding strength and water resistance that is superior to a commercial system by using wood fibres and chitosan-based adhesives. When the mass ratio of solid content in the adhesive and absolute dry wood fibres was 3%, the bonding strength and water resistance of the wood fibre composite reached the optimal level, which was significantly improved over that of wood fibre composites without adhesive and completely met the requirements of the Chinese national standard GB/T 11718-2009. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations revealed that the excellent performance of the binder might partly be due to the amide linkages and hydrogen bonding between wood fibres and the chitosan-based adhesive. We believe that this strategy could open new insights into the design of environment-friendly wood fibre composites with high bonding strength and water resistance for multifunctional applications. PMID:29765653

Environment-friendly wood fibre composite with high bonding strength and water resistance

NASA Astrophysics Data System (ADS)

Ji, Xiaodi; Dong, Yue; Nguyen, Tat Thang; Chen, Xueqi; Guo, Minghui

2018-04-01

With the growing depletion of wood-based materials and concerns over emissions of formaldehyde from traditional wood fibre composites, there is a desire for environment-friendly binders. Herein, we report a green wood fibre composite with specific bonding strength and water resistance that is superior to a commercial system by using wood fibres and chitosan-based adhesives. When the mass ratio of solid content in the adhesive and absolute dry wood fibres was 3%, the bonding strength and water resistance of the wood fibre composite reached the optimal level, which was significantly improved over that of wood fibre composites without adhesive and completely met the requirements of the Chinese national standard GB/T 11718-2009. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations revealed that the excellent performance of the binder might partly be due to the amide linkages and hydrogen bonding between wood fibres and the chitosan-based adhesive. We believe that this strategy could open new insights into the design of environment-friendly wood fibre composites with high bonding strength and water resistance for multifunctional applications.

A Jurassic wood providing insights into the earliest step in Ginkgo wood evolution.

PubMed

Jiang, Zikun; Wang, Yongdong; Philippe, Marc; Zhang, Wu; Tian, Ning; Zheng, Shaolin

2016-12-16

The fossil record of Ginkgo leaf and reproductive organs has been well dated to the Mid-Jurassic (170 Myr). However, the fossil wood record that can safely be assigned to Ginkgoales has not yet been reported from strata predating the late Early Cretaceous (ca. 100 Myr). Here, we report a new fossil wood from the Mid-Late Jurassic transition deposit (153-165 Myr) of northeastern China. The new fossil wood specimen displays several Ginkgo features, including inflated axial parenchyma and intrusive tracheid tips. Because it is only slightly younger than the oldest recorded Ginkgo reproductive organs (the Yima Formation, 170 Myr), this fossil wood very probably represents the oldest bona fide fossil Ginkgo wood and the missing ancestral form of Ginkgo wood evolution.

A Jurassic wood providing insights into the earliest step in Ginkgo wood evolution

NASA Astrophysics Data System (ADS)

Jiang, Zikun; Wang, Yongdong; Philippe, Marc; Zhang, Wu; Tian, Ning; Zheng, Shaolin

2016-12-01

The fossil record of Ginkgo leaf and reproductive organs has been well dated to the Mid-Jurassic (170 Myr). However, the fossil wood record that can safely be assigned to Ginkgoales has not yet been reported from strata predating the late Early Cretaceous (ca. 100 Myr). Here, we report a new fossil wood from the Mid-Late Jurassic transition deposit (153-165 Myr) of northeastern China. The new fossil wood specimen displays several Ginkgo features, including inflated axial parenchyma and intrusive tracheid tips. Because it is only slightly younger than the oldest recorded Ginkgo reproductive organs (the Yima Formation, 170 Myr), this fossil wood very probably represents the oldest bona fide fossil Ginkgo wood and the missing ancestral form of Ginkgo wood evolution.

Ecology of coarse wood decomposition by the saprotrophic fungus Fomes fomentarius.

PubMed

Větrovský, Tomáš; Voříšková, Jana; Snajdr, Jaroslav; Gabriel, Jiří; Baldrian, Petr

2011-07-01

Saprotrophic wood-inhabiting basidiomycetes are the most important decomposers of lignin and cellulose in dead wood and as such they attracted considerable attention. The aims of this work were to quantify the activity and spatial distribution of extracellular enzymes in coarse wood colonised by the white-rot basidiomycete Fomes fomentarius and in adjacent fruitbodies of the fungus and to analyse the diversity of the fungal and bacterial community in a fungus-colonised wood and its potential effect on enzyme production by F. fomentarius. Fungus-colonised wood and fruitbodies were collected in low management intensity forests in the Czech Republic. There were significant differences in enzyme production by F. fomentarius between Betula pendula and Fagus sylvatica wood, the activity of cellulose and xylan-degrading enzymes was significantly higher in beech wood than in birch wood. Spatial analysis of a sample B. pendula log segment proved that F. fomentarius was the single fungal representative found in the log. There was a high level of spatial variability in the amount of fungal biomass detected, but no effects on enzyme activities were observed. Samples from the fruiting body showed high β-glucosidase and chitinase activities compared to wood samples. Significantly higher levels of xylanase and cellobiohydrolase were found in samples located near the fruitbody (proximal), and higher laccase and Mn-peroxidase activities were found in the distal ones. The microbial community in wood was dominated by the fungus (fungal to bacterial DNA ratio of 62-111). Bacterial abundance composition was lower in proximal than distal parts of wood by a factor of 24. These results show a significant level of spatial heterogeneity in coarse wood. One of the explanations may be the successive colonization of wood by the fungus: due to differential enzyme production, the rates of biodegradation of coarse wood are also spatially inhomogeneous.

Gravimetric screening method for fungal decay of paper: inoculation with Trametes versicolor.

PubMed

Råberg, Ulrika; Hafrén, Jonas

2009-10-01

The European standard test EN 113 for fungal degradation of solid wood has been adapted for degradation of paper by white rot fungus (Trametes versicolor). Fungal degradation of paper sheets may potentially be used for screening different wood preservatives on paper instead of solid wood. The paper samples showed higher relative mass losses compared to wood, and samples pretreated with boric acid, copper sulfate and polymerized linseed oil were successfully tested for biodegradation using the paper sheet method. The results on paper degradation were compared with wood, both as wood blocks (according to standard test) and wood cut in sections forming layered structures mimicking paper layers.

Wood Specific Gravity Variations and Biomass of Central African Tree Species: The Simple Choice of the Outer Wood

PubMed Central

Bastin, Jean-François; Fayolle, Adeline; Tarelkin, Yegor; Van den Bulcke, Jan; de Haulleville, Thales; Mortier, Frederic; Beeckman, Hans; Van Acker, Joris; Serckx, Adeline; Bogaert, Jan; De Cannière, Charles

2015-01-01

Context Wood specific gravity is a key element in tropical forest ecology. It integrates many aspects of tree mechanical properties and functioning and is an important predictor of tree biomass. Wood specific gravity varies widely among and within species and also within individual trees. Notably, contrasted patterns of radial variation of wood specific gravity have been demonstrated and related to regeneration guilds (light demanding vs. shade-bearing). However, although being repeatedly invoked as a potential source of error when estimating the biomass of trees, both intraspecific and radial variations remain little studied. In this study we characterized detailed pith-to-bark wood specific gravity profiles among contrasted species prominently contributing to the biomass of the forest, i.e., the dominant species, and we quantified the consequences of such variations on the biomass. Methods Radial profiles of wood density at 8% moisture content were compiled for 14 dominant species in the Democratic Republic of Congo, adapting a unique 3D X-ray scanning technique at very high spatial resolution on core samples. Mean wood density estimates were validated by water displacement measurements. Wood density profiles were converted to wood specific gravity and linear mixed models were used to decompose the radial variance. Potential errors in biomass estimation were assessed by comparing the biomass estimated from the wood specific gravity measured from pith-to-bark profiles, from global repositories, and from partial information (outer wood or inner wood). Results Wood specific gravity profiles from pith-to-bark presented positive, neutral and negative trends. Positive trends mainly characterized light-demanding species, increasing up to 1.8 g.cm-3 per meter for Piptadeniastrum africanum, and negative trends characterized shade-bearing species, decreasing up to 1 g.cm-3 per meter for Strombosia pustulata. The linear mixed model showed the greater part of wood specific gravity variance was explained by species only (45%) followed by a redundant part between species and regeneration guilds (36%). Despite substantial variation in wood specific gravity profiles among species and regeneration guilds, we found that values from the outer wood were strongly correlated to values from the whole profile, without any significant bias. In addition, we found that wood specific gravity from the DRYAD global repository may strongly differ depending on the species (up to 40% for Dialium pachyphyllum). Main Conclusion Therefore, when estimating forest biomass in specific sites, we recommend the systematic collection of outer wood samples on dominant species. This should prevent the main errors in biomass estimations resulting from wood specific gravity and allow for the collection of new information to explore the intraspecific variation of mechanical properties of trees. PMID:26555144

Wood Specific Gravity Variations and Biomass of Central African Tree Species: The Simple Choice of the Outer Wood.

PubMed

Bastin, Jean-François; Fayolle, Adeline; Tarelkin, Yegor; Van den Bulcke, Jan; de Haulleville, Thales; Mortier, Frederic; Beeckman, Hans; Van Acker, Joris; Serckx, Adeline; Bogaert, Jan; De Cannière, Charles

2015-01-01

Wood specific gravity is a key element in tropical forest ecology. It integrates many aspects of tree mechanical properties and functioning and is an important predictor of tree biomass. Wood specific gravity varies widely among and within species and also within individual trees. Notably, contrasted patterns of radial variation of wood specific gravity have been demonstrated and related to regeneration guilds (light demanding vs. shade-bearing). However, although being repeatedly invoked as a potential source of error when estimating the biomass of trees, both intraspecific and radial variations remain little studied. In this study we characterized detailed pith-to-bark wood specific gravity profiles among contrasted species prominently contributing to the biomass of the forest, i.e., the dominant species, and we quantified the consequences of such variations on the biomass. Radial profiles of wood density at 8% moisture content were compiled for 14 dominant species in the Democratic Republic of Congo, adapting a unique 3D X-ray scanning technique at very high spatial resolution on core samples. Mean wood density estimates were validated by water displacement measurements. Wood density profiles were converted to wood specific gravity and linear mixed models were used to decompose the radial variance. Potential errors in biomass estimation were assessed by comparing the biomass estimated from the wood specific gravity measured from pith-to-bark profiles, from global repositories, and from partial information (outer wood or inner wood). Wood specific gravity profiles from pith-to-bark presented positive, neutral and negative trends. Positive trends mainly characterized light-demanding species, increasing up to 1.8 g.cm-3 per meter for Piptadeniastrum africanum, and negative trends characterized shade-bearing species, decreasing up to 1 g.cm-3 per meter for Strombosia pustulata. The linear mixed model showed the greater part of wood specific gravity variance was explained by species only (45%) followed by a redundant part between species and regeneration guilds (36%). Despite substantial variation in wood specific gravity profiles among species and regeneration guilds, we found that values from the outer wood were strongly correlated to values from the whole profile, without any significant bias. In addition, we found that wood specific gravity from the DRYAD global repository may strongly differ depending on the species (up to 40% for Dialium pachyphyllum). Therefore, when estimating forest biomass in specific sites, we recommend the systematic collection of outer wood samples on dominant species. This should prevent the main errors in biomass estimations resulting from wood specific gravity and allow for the collection of new information to explore the intraspecific variation of mechanical properties of trees.

Quantifying Acoustic Uncertainty Due to Marine Mammals and Fish Near the Shelfbreak Front off Cape Hatteras

DTIC Science & Technology

2014-09-30

and Fish Near the Shelfbreak Front off Cape Hatteras James F. Lynch MS #11, Woods Hole Oceanographic Institution Woods Hole, MA 02543 Phone...508) 289-2230 Fax: (508) 457-2194 e-mail: jlynch@whoi.edu Glen Gawarkiewicz MS#21, Woods Hole Oceanographic Institution Woods Hole, MA 02543...Phone: (508) 289-2913 Fax: (508) 457-2181 e-mail: gleng@whoi.edu Ying-Tsong Lin MS #11, Woods Hole Oceanographic Institution Woods Hole, MA 02543

Wood Preference of Reticulitermes virginicus (Blattodea: Rhinotermitidae) Using No-, Two-, and Four-Choice Designs and Seven Different Measures of Wood Consumption.

PubMed

Lee, T-Y; Forschler, B T

2016-04-01

Three hundred Reticulitermes virginicus (Banks) workers were exposed to three 1-cm3 wood blocks of either Quercus sp. (Red Oak), Populus sp. (Poplar), Pinus sp. (Pine), or Sequoia sp. (Redwood) placed into one of the three bioassay designs (no-, two-, and four-choice) for 21 d. Termite wood consumption was measured by wood weight loss, resistance class, and visual rating. Wood consumption rates were determined using four formulas in addition to two standardized visual rating scales (American Society for Testing and Materials [ASTM] and American Wood Protection Association [AWPA]) and a preference ranking obtained for each measure. The wood consumption formula, rating scale, and preference rankings were compared by bioassay design. The overall preference ranking of the four wood types as determined by the combination of all three designs was—1) Pine, 2) Red Oak, 3) Redwood, and 4) Poplar. Results indicate that bioassay design influenced both wood consumption and preference rankings. A no-choice design can determine aversion; a four-choice design the most preferred wood; and a two-choice design can illuminate the fine details of comparative preference. The different formulas employed for calculation of consumption rate influenced preference ranking in the no- and four-choice designs but not the two-choice design.

Traits drive global wood decomposition rates more than climate.

PubMed

Hu, Zhenhong; Michaletz, Sean T; Johnson, Daniel J; McDowell, Nate G; Huang, Zhiqun; Zhou, Xuhui; Xu, Chonggang

2018-06-14

Wood decomposition is a major component of the global carbon cycle. Decomposition rates vary across climate gradients, which is thought to reflect the effects of temperature and moisture on the metabolic kinetics of decomposers. However, decomposition rates also vary with wood traits, which may reflect the influence of stoichiometry on decomposer metabolism as well as geometry relating the surface areas that decomposers colonize with the volumes they consume. In this paper, we combined metabolic and geometric scaling theories to formalize hypotheses regarding the drivers of wood decomposition rates, and assessed these hypotheses using a global compilation of data on climate, wood traits, and wood decomposition rates. Our results are consistent with predictions from both metabolic and geometric scaling theories. Approximately half of the global variation in decomposition rates was explained by wood traits (nitrogen content and diameter), while only a fifth was explained by climate variables (air temperature, precipitation, and relative humidity). These results indicate that global variation in wood decomposition rates is best explained by stoichiometric and geometric wood traits. Our findings suggest that inclusion of wood traits in global carbon cycle models can improve predictions of carbon fluxes from wood decomposition. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Patterns of auxin distribution during gravitational induction of reaction wood in poplar and pine.

PubMed

Hellgren, Jenny M; Olofsson, Kjell; Sundberg, Björn

2004-05-01

Gravistimulation of tree stems affects wood development by unilaterally inducing wood with modified properties, called reaction wood. Commonly, it also stimulates cambial growth on the reaction wood side. Numerous experiments involving applications of indole-3-acetic acid (IAA) or IAA-transport inhibitors have suggested that reaction wood is induced by a redistribution of IAA around the stem. However, in planta proof for this model is lacking. Therefore, we have mapped endogenous IAA distribution across the cambial region tissues in both aspen (Populus tremula, denoted poplar) and Scots pine (Pinus sylvestris) trees forming reaction wood, using tangential cryosectioning combined with sensitive gas chromatography-mass spectrometry analysis. Moreover, we have documented the kinetics of IAA during reaction wood induction in these species. Our analysis of endogenous IAA demonstrates that reaction wood is formed without any obvious alterations in IAA balance. This is in contrast to gravitropic responses in roots and shoots where a redistribution of IAA has been documented. It is also of interest that cambial growth on the tension wood side was stimulated without an increase in IAA. Taken together, our results suggest a role for signals other than IAA in the reaction wood response, or that the gravitational stimulus interacts with the IAA signal transduction pathway.

Wood in New Zealand's Native Forest Streams. Recent Advances

NASA Astrophysics Data System (ADS)

Mark, M. A.; Davies-Colley, R.

2005-05-01

We conducted a series of research projects to investigate the importance of wood in native forested streams of New Zealand. We examined abundance and geomorphic role of wood in 18 pristine native forest streams (channel width: 3-6 m) throughout New Zealand. Forest type and geographic location had no discernable influence on wood abundance, possibly reflecting the confounding influences of local features (e.g., tree fall regime) and methodology (`snap-shot' survey of a dynamic system). Number (18-66 per 100 m) and dead wood volume (85-470 m3 ha-1) of stream logs were at the high end of the international range. Living trees contributed up to 25% of total wood, and tree ferns were strongly represented (up to 11% of volume). The largest 10% of pieces contributed 75% of the total volume. The importance of the large wood pieces (>10 m3) was explored further with surveys within that watershed containing the site with the greatest wood volume. The largest pieces were rare but seemed relatively uniformly distributed. To explore the biological consequences of stream wood, we studied use of wood-related micro-habitat by the crayfish (Paranephrops planifrons White). Our findings suggest that wood is an important component of New Zealand's forested stream ecosystems.

Evaluating wood-based composites for incipient fungal decay with the immunodiagnostic wood decay test.

Treesearch

C.A. Clausen; L. Haughton; C. Murphy

2003-01-01

Early and accurate detection of the extent of fungal deterioration during forensic inspection of the building envelope would eliminate excessive or unnecessary replacement of wood-based building materials. Areas of water infiltration in wood-framed building envelopes in the Pacific Northwest were evaluated visually and sampled for moisture content. Wood samples were...

Ultrasonic-Based Nondestructive Evaluation Methods for Wood: A Primer and Historical Review

Treesearch

Adam C. Senalik; Greg Schueneman; Robert J. Ross

2014-01-01

The authors conducted a review of ultrasonic testing and evaluation of wood and wood products, starting with a description of basic ultrasonic inspection setups and commonly used equations. The literature review primarily covered wood research presented between 1965 and 2013 in the Proceedings of the Nondestructive Testing of Wood Symposiums. A table that lists the...

Understanding key issues of sustainable wood production in the Pacific Northwest.

Treesearch

Robert L. Deal; Seth M. White

2005-01-01

Researchers involved with the Pacific Northwest (PNW) Research Station Sustainable Wood Production Initiative have outlined some of the barriers and opportunities for sustainable wood production in the region. Sustainable wood production is defined as the capacity of forests to produce wood, products, and services on a long-term basis and in the context of human...

CCA-TREATED WOOD DISPOSED IN LANDFILLS AND LIFE-CYCLE TRADE-OFFS WITH WASTE-TO-ENERGY AND MSW LANDFILL DISPOSAL

EPA Science Inventory

Chromated copper arsenate (CCA) treated wood is a preservative treated wood construction product that grew in use in the 1970s for both residential and industrial applications. In the U.S. CCA-treated wood is disposed primarily within landfills, however some of the wood is combu...

Gene expression analysis of wood decay fungus Fibroporia Radiculosa grown In ACQ-treated wood

Treesearch

Ayfer Akgul; Ali Akgul; Juliet D. Diehl Tang

2018-01-01

Copper-tolerant brown-rot fungi are able todegrade wood treated with copper or copper-based wood preservatives. This research used quantitative reverse transcriptase polymerase chain reaction to explore what genes of the brown-rot fungus, Fibroporia radiculosa, were expressed when the fungus was overcoming the wood preservatives and decaying the...

Selection and application of exterior stains for wood

Treesearch

R. Sam Williams; William C. Feist

1999-01-01

Exterior stains for wood protect the wood surface from sunlight and moisture. Because stains are formulated to penetrate the wood surface, they are not prone to crack or peel as can film-forming finishes, such as paints. This publication describes the properties of stains and wood, methods for applying stains, and the expected service life of stains.

Structure and Function of Wood

Treesearch

Alex C. Wiedenhoeft

2012-01-01

Wood is a complex biological structure, a composite of many cell types and chemistries acting together to serve the needs of living plant. Attempting to understand wood inthe context of wood technology, we have often overlooked the basic fact that wood evolved over the course of millions of years to serve three main functions in plants-conduction of water from the...

Users guide for WoodCite, a product cost quotation tool for wood component manufacturers [computer program

Treesearch

Jeff Palmer; Adrienn Andersch; Jan Wiedenbeck; Urs. Buehlmann

2014-01-01

WoodCite is a Microsoft® Access-based application that allows wood component manufacturers to develop product price quotations for their current and potential customers. The application was developed by the U.S. Forest Service and Virginia Polytechnic Institute and State University, in cooperation with the Wood Components Manufacturers Association.

Bioprocessing preservative-treated waste wood

Treesearch

Barbara L. Illman; Vina W. Yang; Les Ferge

2000-01-01

Disposal of preservative-treated waste wood is a growing problem worldwide. Bioprocessing the treated wood offers one approach to waste management under certain conditions. One goal is to use wood decay fungi to reduce the volume of waste with an easily managed system in a cost-effective manner. Wood decay fungi were obtained from culture collections in the Mycology...

Moisture relations and physical properties of wood

Treesearch

Samuel V. Glass; Samuel L. Zelinka

2010-01-01

Wood, like many natural materials, is hygroscopic; it takes on moisture from the surrounding environment. Moisture exchange between wood and air depends on the relative humidity and temperature of the air and the current amount of water in the wood. This moisture relationship has an important influence on wood properties and performance. Many of the challenges of using...

Weathering characteristics of wood plastic composites reinforced with extracted or delignified wood flour

Treesearch

Yao Chen; Nicole M. Stark; Mandla A. Tshabalala; Jianmin Gao; Yongming Fan

2016-01-01

This study investigated weathering performance of an HDPE wood plastic composite reinforced with extracted or delignified wood flour (WF). The wood flour was pre-extracted with three different solvents, toluene/ethanol (TE), acetone/water (AW), and hot water (HW), or sodium chlorite/acetic acid. The spectral properties of the composites before and after artificial...

A review of double-diffusion wood preservation suitable for Alaska.

Treesearch

K. Josephine Pavia

2006-01-01

Currently, all treated lumber used in Alaska is imported from the 48 contiguous states and Canada because there are no wood-treating facilities in Alaska. This report explores conventional and alternative wood-treating methods and reviews previous studies and laboratory tests on treated wood. In investigating wood treatment as a possible processing option for Alaska...

Full field stress/strain analysis : use of Moire and TSA for wood structural assemblies

Treesearch

R. W. Wolfe; R. E. Rowlands; C. H. Lin

1994-01-01

Laboratory and field experiments in wood engineering often rely on different types of devices to measure strain. Each type has certain limitations and characteristics that generally dictate its applicability to wood. Some of the issues related to using traditional strain measurement devices on wood and wood-based materials are discussed in this paper.

Factors that lead to failure with wood adhesive bonds

Treesearch

Charles R. Frihart; James F. Beecher

2016-01-01

Understanding what makes a good wood adhesive is difficult since the type of adhesive, wood species, bonding process, and resultant products vary considerably. Wood bonds are subjected to a variety of tests that reflect the different product performance criteria in diverse countries. The most common tests involve some type of moisture resistance; both wood and adhesive...

Housing and the wood industry, trends & market conditions

Treesearch

Urs Buehlmann; Matt Bumgardner; Al Schuler; K. Koenig

2011-01-01

Housing markets continue to have major impacts on the secondary wood industry. So, what are the steps being taken by wood products manufacturers in order to stay viable? As a follow-up to last year's article, "Housing Market's Impact on the Secondary Woodworking Industry" (Wood & Wood Products, July 2010), the focus of this year's study was...

Extractives in eastern hardwoods : a review

Treesearch

John W. Rowe

1979-01-01

This report extensively reviews the chemistry of extractives from wood and bark of hardwoods from the eastern United States. While such extractives are not used to a great extent commercially, they may influence properties of the wood and performance of wood products. For example, extractives can protect wood from decay, add color and odor to wood, accent grain pattern...

Aircraft Wood Structures, Covering and Finishing Methods (Course Outline), Aviation Mechanics 2 (Air Frame): 9065.01.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

This document presents an outline for a 135-hour course designed to familiarize the student with aircraft wood structures and related Federal Aviation Agency requirements. Topics outlined are identification of defects on wood samples, defining terms used on wood structures, inspecting wood structure together with servicing and repair of wood…

Achieving wood energy potentials: evidence in northeastern Minnesota.

Treesearch

Dennis P. Bradley; David C. Lothner

1987-01-01

A study of wood energy potential in northeastern Minnesota concludes that (1) the forests of the region could support a much larger wood energy harvest without significant cost increases for other forest products; (2) existing stands are predominantly overmature and cutting more now will enhance future wood supplies for all users; (3) converting to wood energy could...

Relationship of wood surface energy to surface composition

Treesearch

Feipeng P. Liu; Timothy G. Rials; John Simonsen

1998-01-01

The wood cell wall is composed of cellulose, lignin, hemicelluloses, and extractives. Thus, the surface energy of the wood material must be some combination of the surface energies of these components. The influence of extractives on wood surface chemistry can be important in diverse industrial applications, such as coating, pulping, and wood-based composites. In this...

Wood-based composites and panel products

Treesearch

John A. Youngquist

1999-01-01

Because wood properties vary among species, between trees of the same species, and between pieces from the same tree, solid wood cannot match reconstituted wood in the range of properties that can be controlled in processing. When processing variables are properly selected, the end result can sometimes surpass nature’s best effort. With solid wood, changes in...

Fire resistance of exposed wood members

Treesearch

Robert H. White

2004-01-01

Fire resistance data on exposed wood beams and columns are plentiful, but few studies have been done on exposed wood members in tension and in decks. To provide data to verify the application of a new calculation procedure, a limited series of fire resistance tests were conducted on wood members loaded in tension and on exposed wood decks.

Effects of chemically modified wood on bond durability

Treesearch

Rishawn Brandon; Rebecca E. Ibach; Charles R. Frihart

2005-01-01

Chemical modification of wood can improve its dimensional stability and resistance to biological degradation and moisture, but modification can also create a new surface for bonding. Acetylation of wood results in the loss of hydroxyl groups, making the wood more hydrophobic and reduces its ability to hydrogen-bond with the adhesive. In contrast, reacting wood with...

Characterization of novolac type liquefied wood/phenol/formaldehyde (LWPF) resin

Treesearch

Hui Pan; Todd F. Shupe; Chung-Yun Hse

2009-01-01

Novolac type liquefied wood/phenol/formaldehyde (LWPF) resins were synthesized from liquefied wood and formaldehyde. The average molecular weight of the LWPF resin made from the liquefied wood reacted in an atmospheric three neck flask increased with increasing P/W ratio. However, it decreased with increasing phenol/wood ratio when using a sealed Parr reactor. On...

Bond quality of phenol-based adhesives containing liquefied creosote-treated wood

Treesearch

Chung-Yun Hse; Feng Fu; Hui Pan

2009-01-01

Liquefaction of spent creosote-treated wood was studied to determine the technological practicability of its application in converting treated wood waste into resin adhesives. A total of 144 plywood panels were fabricated with experimental variables included 2 phenol to wood (P/W) ratios in liquefaction, 6 resin formulations (3 formaldehyde/liquefied wood (F/...

Micronized copper wood preservatives: an efficiency and potential health risk assessment for copper-based nanoparticles.

PubMed

Civardi, Chiara; Schwarze, Francis W M R; Wick, Peter

2015-05-01

Copper (Cu) is an essential biocide for wood protection, but fails to protect wood against Cu-tolerant wood-destroying fungi. Recently Cu particles (size range: 1 nm-25 μm) were introduced to the wood preservation market. The new generation of preservatives with Cu-based nanoparticles (Cu-based NPs) is reputedly more efficient against wood-destroying fungi than conventional formulations. Therefore, it has the potential to become one of the largest end uses for wood products worldwide. However, during decomposition of treated wood Cu-based NPs and/or their derivate may accumulate in the mycelium of Cu-tolerant fungi and end up in their spores that are dispersed into the environment. Inhaled Cu-loaded spores can cause harm and could become a potential risk for human health. We collected evidence and discuss the implications of the release of Cu-based NPs by wood-destroying fungi and highlight the exposure pathways and subsequent magnitude of health impact. Copyright © 2015 Elsevier Ltd. All rights reserved.

Syringyl-rich lignin renders poplars more resistant to degradation by wood decay fungi.

PubMed

Skyba, Oleksandr; Douglas, Carl J; Mansfield, Shawn D

2013-04-01

In order to elucidate the effects of lignin composition on the resistance of wood to degradation by decay fungi, wood specimens from two transgenic poplar lines expressing an Arabidopsis gene encoding ferulate 5-hydroxylase (F5H) driven by the cinnimate-4-hydroxylase promoter (C4H::F5H) that increased syringyl/guaiacyl (S/G) monolignol ratios relative to those in the untransformed control wood were incubated with six different wood decay fungi. Alterations in wood weight and chemical composition were monitored over the incubation period. The results showed that transgenic poplar lines extremely rich in syringyl lignin exhibited a drastically improved resistance to degradation by all decay fungi evaluated. Lignin monomer composition and its distribution among cell types and within different cell layers were the sole wood chemistry parameters determining wood durability. Since transgenic poplars with exceedingly high syringyl contents were recalcitrant to degradation, where wood durability is a critical factor, these genotypes may offer improved performance.

Syringyl-Rich Lignin Renders Poplars More Resistant to Degradation by Wood Decay Fungi

PubMed Central

Skyba, Oleksandr; Douglas, Carl J.

2013-01-01

In order to elucidate the effects of lignin composition on the resistance of wood to degradation by decay fungi, wood specimens from two transgenic poplar lines expressing an Arabidopsis gene encoding ferulate 5-hydroxylase (F5H) driven by the cinnimate-4-hydroxylase promoter (C4H::F5H) that increased syringyl/guaiacyl (S/G) monolignol ratios relative to those in the untransformed control wood were incubated with six different wood decay fungi. Alterations in wood weight and chemical composition were monitored over the incubation period. The results showed that transgenic poplar lines extremely rich in syringyl lignin exhibited a drastically improved resistance to degradation by all decay fungi evaluated. Lignin monomer composition and its distribution among cell types and within different cell layers were the sole wood chemistry parameters determining wood durability. Since transgenic poplars with exceedingly high syringyl contents were recalcitrant to degradation, where wood durability is a critical factor, these genotypes may offer improved performance. PMID:23396333

Silicification of wood adopted for barrel production using pure silicon alkoxides in gas phase to avoid microbial colonisation.

PubMed

Guzzon, Raffaele; Widmann, Giacomo; Bertoldi, Daniela; Nardin, Tiziana; Callone, Emanuela; Nicolini, Giorgio; Larcher, Roberto

2015-02-01

The paper presents a new approach, covering wood with silica-based material in order to protect it from spoilage due to microbial colonisation and avoiding the loss of the natural features of the wood. Wood specimens derived from wine barrels were treated with methyltriethoxysilane in gas phase, leading to the deposition of a silica nanofilm on the surface. (29)Si and (13)C solid state Nuclear Magnetic Resonance and Scanning Electron Microscope-Energy Dispersive X-ray analysis observations showed the formation of a silica polymeric film on the wood samples, directly bonding with the wood constituents. Inductively Coupled Plasma-Mass Spectroscopy quantification of Si showed a direct correlation between the treatment time and silica deposition on the surface of the wood. The silica-coated wood counteracted colonisation by the main wine spoilage microorganisms, without altering the migration from wood to wine of 21 simple phenols measured using a HPLC-Electrochemical Coulometric Detection. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cytochemical localization of cellulases in decayed and nondecayed wood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murmanis, L.; Highley, T.L.; Palmer, J.G.

1987-01-01

Sawdust from undecayed western hemlock wood and from wood previously decayed by the brown-rot fungus Poria placenta or by the white-rot fungus Ganoderma applanatum was incubated with commercial cellulase from Trichoderma viride. Samples were treated cytochemically to locate cellulase activity and examined by TEM. Results showed that cellulase degraded undecayed wood extensively, with the attack starting on the outer border of a cell wall and progressing inside. Wood decayed by P. placenta, with or without cellulase incubation, and treated by the cytochemical test showed uniform distribution of electron dense particles throughout the cell walls. In wood decayed by G. applanatum,more » cellulase degradation was similar to that in undecayed wood. From measurements of particle diameter it is suggested that electron dense particles are cellulase. It is concluded that brown-rot and white-rot fungi have different effects on the microstructure of wood. The brown-rot fungus appears to open the wood microstructure so that cellulase can diffuse throughout the degraded tracheid wall.« less

Bacteria in decomposing wood and their interactions with wood-decay fungi.

PubMed

Johnston, Sarah R; Boddy, Lynne; Weightman, Andrew J

2016-11-01

The fungal community within dead wood has received considerable study, but far less attention has been paid to bacteria in the same habitat. Bacteria have long been known to inhabit decomposing wood, but much remains underexplored about their identity and ecology. Bacteria within the dead wood environment must interact with wood-decay fungi, but again, very little is known about the form this takes; there are indications of both antagonistic and beneficial interactions within this fungal microbiome. Fungi are hypothesised to play an important role in shaping bacterial communities in wood, and conversely, bacteria may affect wood-decay fungi in a variety of ways. This minireview considers what is currently known about bacteria in wood and their interactions with fungi, and proposes possible associations based on examples from other habitats. It aims to identify key knowledge gaps and pressing questions for future research. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Sunken wood habitat for thiotrophic symbiosis in mangrove swamps.

PubMed

Laurent, Mélina C Z; Gros, Olivier; Brulport, Jean-Pierre; Gaill, Françoise; Bris, Nadine Le

2009-03-01

Large organic falls to the benthic environment, such as dead wood or whale bones, harbour organisms relying on sulfide-oxidizing symbionts. Nothing is known however, concerning sulfide enrichment at the wood surface and its relation to wood colonization by sulfide-oxidizing symbiotic organisms. In this study we combined in situ hydrogen sulfide and pH measurements on sunken wood, with associated fauna microscopy analyses in a tropical mangrove swamp. This shallow environment is known to harbour thiotrophic symbioses and is also abundantly supplied with sunken wood. A significant sulfide enrichment at the wood surface was revealed. A 72h sequence of measurements emphasized the wide fluctuation of sulfide levels (0.1->100muM) over time with both a tidal influence and rapid fluctuations. Protozoans observed on the wood surface were similar to Zoothamnium niveum and to vorticellids. Our SEM observations revealed their association with ectosymbiotic bacteria, which are likely to be sulfide-oxidizers. These results support the idea that sunken wood surfaces constitute an environment suitable for sulfide-oxidizing symbioses.

Does reintroducing large wood influence the hydraulic landscape of a lowland river system?

NASA Astrophysics Data System (ADS)

Matheson, Adrian; Thoms, Martin; Reid, Michael

2017-09-01

Our understanding of the effectiveness of reintroduced large wood for restoration is largely based on studies from high energy river systems. By contrast, few studies of the effectiveness of reintroducing large wood have been undertaken on large, low energy, lowland river systems: river systems where large wood is a significant physical feature on the in-channel environment. This study investigated the effect of reintroduced large wood on the hydraulic landscape of the Barwon-Darling River, Australia, at low flows. To achieve this, the study compared three hydraulic landscapes of replicated reference (naturally wooded), control (unwooded,) and managed (wood reintroduced) treatments on three low flow periods. These time periods were prior to the reintroduction of large wood to managed reaches; several months after the reintroduction of large wood into the managed reaches; and then more than four years after wood reintroduction following several large flood events. Hydraulic landscapes of reaches were characterised using a range of spatial measures calculated from velocity measurements taken with a boat-mounted Acoustic Doppler Profiler. We hypothesised that reintroduced large wood would increase the diversity of the hydraulic landscape at low flows and that managed reaches would be more similar to the reference reaches. Our results suggest that the reintroduction of large wood did not significantly change the character of the hydraulic landscape at the reach scale after several months (p = 0.16) or several years (p = 0.29). Overall, the character of the hydraulic landscape in the managed reaches was more similar to the hydraulic landscape of the control reaches than the hydraulic landscape of the reference reaches, at low flows. Some variability in the hydraulic landscapes was detected over time, and this may reflect reworking of riverbed sediments and sensitivity to variation in discharge. The lack of a response in the low flow hydraulic landscape to the reintroduction of large wood is inferred because the character (the size and complexity of individual pieces) and positioning of large wood in managed reaches did not mimic that of reference reaches effectively despite the abundance of wood pieces being similar in the reference and managed reaches. The results of this study highlight the importance of understanding the natural character and distribution of large wood on hydraulic landscapes in large low energy lowland river systems, especially when reintroducing large wood for river management purposes.

Evaluation of Binding Effects in Wood Flour Board Containing Ligno-Cellulose Nanofibers

PubMed Central

Kojima, Yoichi; Isa, Akiko; Kobori, Hikaru; Suzuki, Shigehiko; Ito, Hirokazu; Makise, Rie; Okamoto, Masaki

2014-01-01

Wood-based materials are used extensively in residual construction worldwide. Most of the adhesives used in wood-based materials are derived from fossil resources, and some are not environmentally friendly. This study explores nanofiber technology as an alternative to such adhesives. Previous studies have shown that the three-dimensional binding effects of cellulose nanofiber (CNF), when mixed with wood flour, can significantly improve the physical and mechanical properties of wood flour board. In this study, ligno-cellulose nanofibers (LCNF) were fabricated by wet disk milling of wood flour. Composite boards of wood flour and LCNF were produced to investigate the binding effect(s) of LCNF. The fabrication of LCNF by disk milling was simple and effective, and its incorporation into wood flour board significantly enhanced the physical and mechanical properties of the board. PMID:28788217

Thermal decomposition of wood: kinetics and degradation mechanisms.

PubMed

Poletto, Matheus; Zattera, Ademir J; Santana, Ruth M C

2012-12-01

The influence of wood components and cellulose crystallinity on the kinetic degradation of different wood species has been investigated using thermogravimetry. Four wood species were studied: Pinus elliottii (PIE), Eucalyptus grandis (EUG), Mezilaurus itauba (ITA) and Dipteryx odorata (DIP). Thermogravimetric results showed that higher extractive contents in the wood accelerate the degradation process and promote an increase in the conversion values at low temperatures. Alternatively, the results indicated that the cellulose crystallinity inhibits wood degradation; organized cellulose regions slow the degradation process because the well-packed cellulose chains impede heat diffusion, which improves the wood's thermal stability. The wood degradation mechanism occurs by diffusion processes when the conversion values are below 0.4. When the conversion values are above 0.5, the degradation is a result of random nucleation with one nucleus in each particle. Copyright © 2012 Elsevier Ltd. All rights reserved.

Analysis on storage off-gas emissions from woody, herbaceous, and torrefied biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tumuluru, Jaya Shankar; Lim, C. Jim; Bi, Xiaotao T.

Wood chips, torrefied wood chips, ground switchgrass, and wood pellets were tested for off-gas emissions during storage. Storage canisters with gas-collection ports were used to conduct experiments at room temperature of 20 °C and in a laboratory oven set at 40 °C. Commercially-produced wood pellets yielded the highest carbon monoxide (CO) emissions at both 20 and 40 °C (1600 and 13,000 ppmv), whereas torrefied wood chips emitted the lowest of about <200 and <2000 ppmv. Carbon dioxide (CO₂) emissions from wood pellets were 3000 ppmv and 42,000 ppmv, whereas torrefied wood chips registered at about 2000 and 25,000 ppmv, atmore » 20 and 40 °C at the end of 11 days of storage. CO emission factors (milligrams per kilogram of biomass) calculated were lowest for ground switchgrass and torrefied wood chips (2.68 and 4.86 mg/kg) whereas wood pellets had the highest CO of about 10.60 mg/kg, respectively, at 40 °C after 11 days of storage. In the case of CO₂, wood pellets recorded the lowest value of 55.46 mg/kg, whereas switchgrass recorded the highest value of 318.72 mg/kg. This study concludes that CO emission factor is highest for wood pellets, CO₂ is highest for switchgrass and CH₄ is negligible for all feedstocks except for wood pellets, which is about 0.374 mg/kg at the end of 11-day storage at 40 °C.« less

Analysis on storage off-gas emissions from woody, herbaceous, and torrefied biomass

DOE PAGES

Tumuluru, Jaya Shankar; Lim, C. Jim; Bi, Xiaotao T.; ...

2015-03-02

Wood chips, torrefied wood chips, ground switchgrass, and wood pellets were tested for off-gas emissions during storage. Storage canisters with gas-collection ports were used to conduct experiments at room temperature of 20 °C and in a laboratory oven set at 40 °C. Commercially-produced wood pellets yielded the highest carbon monoxide (CO) emissions at both 20 and 40 °C (1600 and 13,000 ppmv), whereas torrefied wood chips emitted the lowest of about <200 and <2000 ppmv. Carbon dioxide (CO₂) emissions from wood pellets were 3000 ppmv and 42,000 ppmv, whereas torrefied wood chips registered at about 2000 and 25,000 ppmv, atmore » 20 and 40 °C at the end of 11 days of storage. CO emission factors (milligrams per kilogram of biomass) calculated were lowest for ground switchgrass and torrefied wood chips (2.68 and 4.86 mg/kg) whereas wood pellets had the highest CO of about 10.60 mg/kg, respectively, at 40 °C after 11 days of storage. In the case of CO₂, wood pellets recorded the lowest value of 55.46 mg/kg, whereas switchgrass recorded the highest value of 318.72 mg/kg. This study concludes that CO emission factor is highest for wood pellets, CO₂ is highest for switchgrass and CH₄ is negligible for all feedstocks except for wood pellets, which is about 0.374 mg/kg at the end of 11-day storage at 40 °C.« less

Recent advances quantifying the large wood dynamics in river basins: New methods and remaining challenges

NASA Astrophysics Data System (ADS)

Ruiz-Villanueva, Virginia; Piégay, Hervé; Gurnell, Angela A.; Marston, Richard A.; Stoffel, Markus

2016-09-01

Large wood is an important physical component of woodland rivers and significantly influences river morphology. It is also a key component of stream ecosystems. However, large wood is also a source of risk for human activities as it may damage infrastructure, block river channels, and induce flooding. Therefore, the analysis and quantification of large wood and its mobility are crucial for understanding and managing wood in rivers. As the amount of large-wood-related studies by researchers, river managers, and stakeholders increases, documentation of commonly used and newly available techniques and their effectiveness has also become increasingly relevant as well. Important data and knowledge have been obtained from the application of very different approaches and have generated a significant body of valuable information representative of different environments. This review brings a comprehensive qualitative and quantitative summary of recent advances regarding the different processes involved in large wood dynamics in fluvial systems including wood budgeting and wood mechanics. First, some key definitions and concepts are introduced. Second, advances in quantifying large wood dynamics are reviewed; in particular, how measurements and modeling can be combined to integrate our understanding of how large wood moves through and is retained within river systems. Throughout, we present a quantitative and integrated meta-analysis compiled from different studies and geographical regions. Finally, we conclude by highlighting areas of particular research importance and their likely future trajectories, and we consider a particularly underresearched area so as to stress the future challenges for large wood research.

Aspen SUCROSE TRANSPORTER3 Allocates Carbon into Wood Fibers1[C][W

PubMed Central

Mahboubi, Amir; Ratke, Christine; Gorzsás, András; Kumar, Manoj; Mellerowicz, Ewa J.; Niittylä, Totte

2013-01-01

Wood formation in trees requires carbon import from the photosynthetic tissues. In several tree species, including Populus species, the majority of this carbon is derived from sucrose (Suc) transported in the phloem. The mechanism of radial Suc transport from phloem to developing wood is not well understood. We investigated the role of active Suc transport during secondary cell wall formation in hybrid aspen (Populus tremula × Populus tremuloides). We show that RNA interference-mediated reduction of PttSUT3 (for Suc/H+ symporter) during secondary cell wall formation in developing wood caused thinner wood fiber walls accompanied by a reduction in cellulose and an increase in lignin. Suc content in the phloem and developing wood was not significantly changed. However, after 13CO2 assimilation, the SUT3RNAi lines contained more 13C than the wild type in the Suc-containing extract of developing wood. Hence, Suc was transported into developing wood, but the Suc-derived carbon was not efficiently incorporated to wood fiber walls. A yellow fluorescent protein:PttSUT3 fusion localized to plasma membrane, suggesting that reduced Suc import into developing wood fibers was the cause of the observed cell wall phenotype. The results show the importance of active Suc transport for wood formation in a symplasmically phloem-loading tree species and identify PttSUT3 as a principal transporter for carbon delivery into secondary cell wall-forming wood fibers. PMID:24170204

A foundation monograph of Convolvulus L. (Convolvulaceae)

PubMed Central

Wood, John R.I.; Williams, Bethany R.M.; Mitchell, Thomas C.; Carine, Mark A.; Harris, David J.; Scotland, Robert W.

2015-01-01

Abstract A global revision of Convolvulus L. is presented, Calystegia R.Br. being excluded on pragmatic grounds. One hundred and ninety species are recognised with the greatest diversity in the Irano-Turanian region. All recognised species are described and the majority are illustrated. Distribution details, keys to species identification and taxonomic notes are provided. Four new species, Convolvulus austroafricanus J.R.I.Wood & R.W.Scotland, sp. nov., Convolvulus iranicus J.R.I.Wood & R.W.Scotland, sp. nov., Convolvulus peninsularis J.R.I.Wood & R.W.Scotland, sp. nov. and Convolvulus xanthopotamicus J.R.I.Wood & R.W.Scotland, sp. nov., one new subspecies Convolvulus chinensis subsp. triangularis J.R.I.Wood & R.W.Scotland, subsp. nov., and two new varieties Convolvulus equitans var. lindheimeri J.R.I.Wood & R.W.Scotland, var. nov., Convolvulus glomeratus var. sachalitarum J.R.I.Wood & R.W.Scotland, var. nov. are described. Convolvulus incisodentatus J.R.I.Wood & R.W.Scotland, nom. nov., is provided as a replacement name for the illegitimate Convolvulus incisus Choisy. Several species treated as synonyms of other species in recent publications are reinstated including Convolvulus chinensis Ker-Gawl., Convolvulus spinifer M.Popov., Convolvulus randii Rendle and Convolvulus aschersonii Engl. Ten taxa are given new status and recognised at new ranks: Convolvulus namaquensis (Schltr. ex. A.Meeuse) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus hermanniae subsp. erosus (Desr.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus crenatifolius subsp. montevidensis (Spreng.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus fruticulosus subsp. glandulosus (Webb) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus capituliferus subsp. foliaceus (Verdc.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus hystrix subsp. ruspolii (Dammer ex Hallier f.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus hystrix subsp. inermis (Chiov.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus rottlerianus subsp. stocksii (Boiss.) J.R.I.Wood & R.W.Scotland, comb. et stat. nov., Convolvulus calvertii subsp. ruprechtii (Boiss.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus cephalopodus subsp. bushiricus (Bornm.) J.R.I.Wood & R.W.Scotland, stat. nov. The status of various infraspecific taxa is clarified and numerous taxa are lectotypified. This account represents a new initiative in terms of taxonomic monography, being an attempt to bring together the global approach of the traditional monograph with the more pragmatic and identification-focussed approach of most current floras while at the same time being informed by insights from molecular systematics. PMID:26140023

Pretreatment Characteristics of Waste Oak Wood by Ammonia Percolation

NASA Astrophysics Data System (ADS)

Kim, Jun-Seok; Kim, Hyunjoon; Lee, Jin-Suk; Lee, Joon-Pyo; Park, Soon-Chul

A log of waste oak wood collected from a Korean mushroom farm has been tested for ammonia percolation pretreatment. The waste log has different physical characteristics from that of virgin oak wood. The density of the waste wood was 30% lower than that of virgin oak wood. However, there is little difference in the chemical compositions between the woods. Due to the difference in physical characteristics, the optimal pretreatment conditions were also quite different. While for waste oak the optimum temperature was determined to be 130°C, for virgin oak wood the optimum pretreatment was only achieved at 170°C. Presoaking for 12 h with ammonia solution before pretreatment was helpful to increase the delignification efficiency.

Opportunities to change timber demand through altered timber utilization [Chapter 10

Treesearch

K. E. Skog; D. P. Bradley; H. N. Spelter; I. Durbak; P. J. Ince; W. J. Lange; P. A. Araman; D. B. McKeever; J. I. Zerbe

1990-01-01

This paper discusses opportunities for timber utilization improvement that will 1) increase efficiency of wood use, 2) reduce the cost of wood products and the cost of using wood in applications, and 3) provide new or improved wood products or wood use applications. A key purpose here is to propose and explain technology-influenced projections of 1) costs for...

Detection of wood failure by image processing method: influence of algorithm, adhesive and wood species

Treesearch

Lanying Lin; Sheng He; Feng Fu; Xiping Wang

2015-01-01

Wood failure percentage (WFP) is an important index for evaluating the bond strength of plywood. Currently, the method used for detecting WFP is visual inspection, which lacks efficiency. In order to improve it, image processing methods are applied to wood failure detection. The present study used thresholding and K-means clustering algorithms in wood failure detection...

The central role of wood biology in understanding the durability of wood-coating interactions

Treesearch

Alex C. Wiedenhoeft

2007-01-01

To design effectively for durability, one must actively and honestly assess the material properties and limitations of each of the components in the design system; wood or wood composite, and the coating. Inasmuch as wood coatings are manufactured to specified tolerances from known materials, we have control of that component of the system. Compared to manmade...

Moisture Performance of wood-plastic composites reinforced with extracted and delignified wood flour

Treesearch

Yao Chen; Nicole M. Stark; Mandla A. Tshabalala; Jianmin Gao; Yongming Fan

2014-01-01

This study investigated the effect of using extracted and delignified wood flour on water sorption properties of wood–plastic composites. Wood flour (WF) extraction was performed with three solvent systems: toluene/ethanol (TE), acetone/water (AW), and hot water (HW); delignification was conducted using sodium chlorite/acetic acid solution. A 24 full-factorial...

Wood construction codes issues in the United States

Treesearch

Douglas R. Rammer

2006-01-01

The current wood construction codes find their origin in the 1935 Wood Handbook: Wood as an Engineering Material published by the USDA Forest Service. Many of the current design recommendations can be traced back to statements from this book. Since this time a series of development both historical and recent has led to a multi-layered system for use of wood products in...

Violet light causes photodegradation of wood beyond the zone affected by ultraviolet radiation

Treesearch

Yutaka Kataoka; Makoto Kiguchi; R. Sam Williams; Philip D. Evans

2007-01-01

The limited penetration of wood by light explains why the weathering of wood exposed outdoors is a surface phenomenon. Wood is rapidly degraded by short-wave-length UV radiation, but the penetration of light into wood is positively correlated with its wavelength. Hence, subsurface degradation is likely to be caused by longer-wavelength light that still has sufficient...

The use and market for wood in the electrometallurgical industry

Treesearch

Jeffery L. Wartluft; Jeffery L. Wartluft

1971-01-01

Wood residues, particularly large chips, play an important role in the electric smelting of certain ferro-alloys. This is a report on the characteristics and growth potential of the market for wood in the electrometallurgicaI industry, including a brief account of how wood is used in electrometallurgical processes, a discussion of the preferred form of wood used, a...

Strength of anisotropic wood and synthetic materials. [plywood, laminated wood plastics, glass fiber reinforced plastics, polymeric film, and natural wood

NASA Technical Reports Server (NTRS)

Ashkenazi, Y. K.

1981-01-01

The possibility of using general formulas for determining the strength of different anisotropic materials is considered, and theoretical formulas are applied and confirmed by results of tests on various nonmetallic materials. Data are cited on the strength of wood, plywood, laminated wood plastics, fiber glass-reinforced plastics and directed polymer films.

Allowable bending stresses of wood for use in portable wood ladders

Treesearch

Fred Werren

1975-01-01

A standard for portable wood ladders has been in effect since 1923, and has been revised several times since then. The most recent publication is "American National Standard Safety Standard for Portable Wood Ladders," A14.1-1975, from American National Standards Institute, Inc. Methods of arriving at allowable stresses for wood ladder parts have never been...

The Asian Wood Pellet Markets

Treesearch

Joseph A. Roos; Allen Brackley

2012-01-01

This study examines the three major wood pellet markets in Asia: China, Japan, and South Korea. In contrast to the United States, where most wood pellets are used for residential heating with pellet stoves, a majority of the wood pellets in Asia are used for co-firing at coal-fired power plants. Our analysis indicated that Japan is the largest importer of wood pellets...

Consumer preference study of characteristics of Hawaiian koa wood bowls

Treesearch

Eini C Lowell; Katherine Wilson; Jan Wiedenbeck; Catherine Chan; J. B. Friday; Nicole Evans

2017-01-01

Koa (Acacia koa A. Gray), a species endemic to the Hawaiian Islands, has ecological, cultural, and economic significance. Its wood is prized globally but today, most woodworkers only use koa wood from dead and dying old-growth trees. The general perception of wood from young-growth koa is that it lacks the color and figure of old-growth wood and is...

Characterizing and contrasting instream and riparian coarse wood in western Montana basins

Treesearch

Michael K. Young; Ethan A. Mace; Eric T. Ziegler; Elaine K. Sutherland

2006-01-01

The importance of coarse wood to aquatic biota and stream channel structure is widely recognized, yet characterizations of large-scale patterns in coarse wood dimensions and loads are rare. To address these issues, we censused instream coarse wood ( 2 m long and 10 cm minimum diameter) and sampled riparian coarse wood and channel characteristics in and along 13 streams...

Synthesis and evaluation of borates derived from boric acid for fire and decay protections

Treesearch

George Chen

1999-01-01

The degradation of wood by decay, fire and UV constitutes the three major losses of wood products in use. Commercial wood preservatives including chromated copper arsenate(CCA) and pentachlorophenol(penta) can only protect wood from decay. Dual protections of wood against decay and fire or decay and UV if acheivable are more desirable. Many phosphorus and boron...

Electrochemical corrosion testing of fasteners in extracts of treated wood

Treesearch

Samuel L. Zelinka; Douglas R. Rammer; Donald S. Stone

2008-01-01

A recent change in wood preservatives has highlighted the need for a rapid, quantitative test to measure the corrosion rates of metals in contact with treated wood that could be used to evaluate new fasteners or new wood preservatives. A new method was developed where polarisation resistance tests were conducted on fasteners exposed to a water extract of wood treated...

Drying and control of moisture content and dimensional changes

Treesearch

William T. Simpson

1999-01-01

In the living tree, wood contains large quantities of water. As green wood dries, most of the water is removed. The moisture remaining in the wood tends to come to equilibrium with the relative humidity of the surrounding air. Correct drying, handling, and storage of wood will minimize moisture content changes that might occur after drying when the wood is in service...

Structure and function of wood

Treesearch

Alex Wiedenhoeft

2010-01-01

Wood is a complex biological structure, a composite of many chemistries and cell types acting together to serve the needs of a living plant. Attempting to understand wood in the context of wood technology, we have often overlooked the key and basic fact that wood evolved over the course of millions of years to serve three main functions in plants― conduction of water...

Finite element analyses of two dimensional, anisotropic heat transfer in wood

Treesearch

John F. Hunt; Hongmei Gu

2004-01-01

The anisotropy of wood creates a complex problem for solving heat and mass transfer problems that require analyses be based on fundamental material properties of the wood structure. Inputting basic orthogonal properties of the wood material alone are not sufficient for accurate modeling because wood is a combination of porous fiber cells that are aligned and mis-...

Breakdown and invertebrate colonization of dead wood in wetland, upland, and river habitats

Treesearch

A Braccia; D Batzer

2010-01-01

Breakdown of woody debris in river and upland habitats as well as the interactions between wood and invertebrates have been well described. Studies of wood in wetlands are rare, and far less is known about breakdown and invertebrate use of wood in these transitional habitats. This study experimentally assessed breakdown and invertebrate colonization of wood in a...

New Developments in Wood-Destroying Organisms from the International Research Group on Wood Preservation \\t

Treesearch

Elmer L. Schmidt

1991-01-01

New developments in wood-destroying organisms and in wood protection from the 20th annual meeting (May 1989 at Lappeenranta, Finland) of the International Research Group on Wood Preservation (IRG) are highlighted in the areas of biological control of fungi, dry rot, decay mechanisms and product problems, new techniques, insect problems and control, and developments in...

Wood products used in the construction of low-rise nonresidential buildings in the United States, 2008

Treesearch

David McKeever

2010-01-01

Low-rise nonresidential building construction is an important market for lumber, structural wood panels, nonstructural wood panels, and engineered wood products in the United States. This report examines low-rise nonresidential buildings of four or fewer stories only. Buildings with five or more stories are normally severely restricted by building code from being wood...

Analysis of U.S. household wood energy consumption: 1967-2009

Treesearch

Nianfu Song; Francisco X. Aguilar; Stephen R. Shifley; Michael E. Goerndt

2012-01-01

The residential sector consumes about 23% of the energy derived from wood (wood energy) in the U.S. An estimated error correction model with data from 1967 to 2009 suggests that residential wood energy consumption has declined by an average 3% per year in response to technological progress, urbanization, accessibility of non-wood energy, and other factors associated...

Treatments that enhance physical properties of wood

Treesearch

Roger M. Rowell; Peggy Konkol

1987-01-01

This paper was prepared for anyone who wants to know more about enhancing wood’s physical properties, from the amateur wood carver to the president of a forest products company. The authors describe chemical and physical treatments of wood that enhance the strength, stiffness, water repellency, and stability of wood. Five types of treatments are described: 1. water-...

Physical properties and moisture relations of wood

Treesearch

William Simpson; Anton TenWolde

1999-01-01

The versatility of wood is demonstrated by a wide variety of products. This variety is a result of a spectrum of desirable physical characteristics or properties among the many species of wood. In many cases, more than one property of wood is important to the end product. For example, to select a wood species for a product, the value of appearance- type properties,...

Chronicle of 65 years of wood finishing research at the Forest Products Laboratory

Treesearch

Thomas M. Gorman; William C. Feist

1989-01-01

For 65 years, the Forest Products Laboratory (FPL) in Madison, Wisconsin, has had a continuous and extensive program of research on finishing wood for outdoor use. The research has stressed the fundamental aspects of wood weathering and the interactions of pretreatments and finishes on wood surfaces. This report outlines the history of the FPL wood finishing research...

Evaluation of the accessibility of CCA metals in liquefied CCA-treated wood sludge for recovery and reuse

Treesearch

Hui Pan; Todd F. Shupe; Chung-Yun Hse

2009-01-01

CCA-treated wood was liquefied with polyethylene glycol/glycerin and sulfuric acid. The heavy metals were precipitated by Ca(OH)2 from liquefied CCA-treated wood. The original CCA-treated wood and precipitated wood sludge were fractionated by a modified BCR (Community Bureau of Reference) sequential extraction procedure. The purpose of the BCR...

Domestic market activity in solid wood products in the United States, 1950-1998.

Treesearch

David B. McKeever

2002-01-01

Solid wood is important to the construction, manufacturing, and shipping segments of the U.S. economy. Nearly all new houses are built with wood, and wood building products are used in the construction of nonresidential buildings, and in the upkeep and improvement of existing structures. Solid wood is used extensively to produce and transport manufactured products. It...

Climate Change Mitigation Challenge for Wood Utilization-The Case of Finland.

PubMed

Soimakallio, Sampo; Saikku, Laura; Valsta, Lauri; Pingoud, Kim

2016-05-17

The urgent need to mitigate climate change invokes both opportunities and challenges for forest biomass utilization. Fossil fuels can be substituted by using wood products in place of alternative materials and energy, but wood harvesting reduces forest carbon sink and processing of wood products requires material and energy inputs. We assessed the extended life cycle carbon emissions considering substitution impacts for various wood utilization scenarios over 100 years from 2010 onward for Finland. The scenarios were based on various but constant wood utilization structures reflecting current and anticipated mix of wood utilization activities. We applied stochastic simulation to deal with the uncertainty in a number of input variables required. According to our analysis, the wood utilization decrease net carbon emissions with a probability lower than 40% for each of the studied scenarios. Furthermore, large emission reductions were exceptionally unlikely. The uncertainty of the results were influenced clearly the most by the reduction in the forest carbon sink. There is a significant trade-off between avoiding emissions through fossil fuel substitution and reduction in forest carbon sink due to wood harvesting. This creates a major challenge for forest management practices and wood utilization activities in responding to ambitious climate change mitigation targets.

Rubber-like materials derived from biosourced phenolic resins

NASA Astrophysics Data System (ADS)

Amaral-Labat, G.; Grishechko, L. I.; Silva, G. F. B. Lenz e.; Kuznetsov, B. N.; Fierro, V.; Pizzi, A.; Celzard, A.

2017-07-01

The present work describes new gels derived from cheap, abundant and non-toxic wood bark extracts of phenolic nature, behaving like elastomers. Especially, we show that these materials might be used as rubber springs. Such amazing properties were obtained by a quite simple synthesis based on the autocondensation of flavonoid tannins in water at low pH in the presence of a plasticizer. After gelation and drying, the materials presented elastic properties that could be tuned from hard and brittle to quite soft and deformable, depending on the amount of plasticizer in the starting formulation. Not only the materials containing the relevant amount of plasticizer had stress-strain characteristics in quasi-static and cyclic compression similar to most commercial rubber springs, but they presented outstanding fire retardance, surviving 5 min in a flame at 1000°C in air. Neither flame propagation nor drips were noticed during the fire test, and the materials were auto-extinguishable. These excellent features make these materials potential substitutes to usual organic elastomers.

Release of U(VI) from spent biosorbent immobilized in cement concrete blocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venkobachar, C.; Iyengar, L.; Mishra, U.K.

1995-12-01

This paper deals with cementation as the method for the disposal of spent biosorbent, Ganoderma lucidum (a wood rotting macrofungi) after it is used for the removal of Uranium. Results on the uranium release during the curing of cement-concrete (CC) blocks indicated that placing the spent sorbent at the center of the blocks during their casting yields better immobilization of uranium as compared to the homogeneous mixing of the spent sorbent with the cement. Short term leach tests indicated that the uranium release was negligible in simulated seawater, 1.8% in 0.2 N sodium carbonate and 6.0% in 0.2 N HCl.more » The latter two leachates were used to represent the extreme environmental conditions. It was observed that the presence of the spent biosorbent up to 5% by weight did not affect the compressive strength of CC blocks. Thus cementation technique is suitable for the immobilization of uranium loaded biosorbent for its ultimate disposal.« less

Hydrothermal carbonization of typical components of municipal solid waste for deriving hydrochars and their combustion behavior.

PubMed

Lin, Yousheng; Ma, Xiaoqian; Peng, Xiaowei; Yu, Zhaosheng

2017-11-01

In this work, five typical components were employed as representative pseudo-components to indirectly complete previous established simulation system during hydrothermal carbonization (HTC) of municipal solid waste. The fuel characteristics and combustion behavior of HTC-derived hydrochars were evaluated. Results clearly illustrated that the energy ranks of hydrochars were upgraded after HTC. For paper and wood, superior combustion performances of their hydrochars could achieve under suitable conditions. While for food, none positive enrichments on combustion loss rate were observed for hydrochars due to its high solubilization and decomposition under hot compressed water. It was noteworthy that a new weight loss peak was detected for paper and food, suggesting that new compounds were formed. For rubber, the HTC process made the properties of styrene butadiene rubber more close to natural rubber. Therefore, the first peak of hydrochars became significantly intense. While for plastic, only physical changes of polypropylene and polyethylene were observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polyphenolic profile as a useful tool to identify the wood used in wine aging.

PubMed

Sanz, Miriam; Fernández de Simón, Brígida; Cadahía, Estrella; Esteruelas, Enrique; Muñoz, Angel Ma; Hernández, Ma Teresa; Estrella, Isabel

2012-06-30

Although oak wood is the main material used in cooperage, other species are being considered as possible sources of wood for the production of wines and their derived products. In this work we have compared the phenolic composition of acacia (Robinia pseudoacacia), chestnut (Castanea sativa), cherry (Prunus avium) and ash (Fraxinus excelsior and F. americana) heartwoods, by using HPLC-DAD/ESI-MS/MS (some of these data have been showed in previous paper), as well as the changes that toasting intensity at cooperage produce in each polyphenolic profile. Before toasting, each wood shows a different and specific polyphenolic profile, with both qualitative and quantitative differences among them. Toasting notably changed these profiles, in general, proportionally to toasting intensity and led to a minor differentiation among species in toasted woods, although we also found phenolic markers in toasted woods. Thus, methyl syringate, benzoic acid, methyl vanillate, p-hydroxybenzoic acid, 3,4,5-trimethylphenol and p-coumaric acid, condensed tannins of the procyanidin type, and the flavonoids naringenin, aromadendrin, isosakuranetin and taxifolin will be a good tool to identify cherry wood. In acacia wood the chemical markers will be the aldehydes gallic and β-resorcylic and two not fully identified hydroxycinnamic compounds, condensed tannins of the prorobinetin type, and when using untoasted wood, dihydrorobinetin, and in toasted acacia wood, robinetin. In untoasted ash wood, the presence of secoiridoids, phenylethanoid glycosides, or di and oligolignols will be a good tool, especially oleuropein, ligstroside and olivil, together verbascoside and isoverbascoside in F. excelsior, and oleoside in F. americana. In toasted ash wood, tyrosol, syringaresinol, cyclolovil, verbascoside and olivil, could be used to identify the botanical origin. In addition, in ash wood, seasoned and toasted, neither hydrolysable nor condensed tannins were detected. Lastly, in chestnut wood, gallic and ellagic acids and hydrolysable tannins of both the gallotannin and ellagitannin type, can be used as chemical markers. Copyright © 2011 Elsevier B.V. All rights reserved.

Waste wood as bioenergy feedstock. Climate change impacts and related emission uncertainties from waste wood based energy systems in the UK.

PubMed

Röder, Mirjam; Thornley, Patricia

2018-04-01

Considering the urgent need to shift to low carbon energy carriers, waste wood resources could provide an alternative energy feedstock and at the same time reduce emissions from landfill. This research examines the climate change impacts and related emission uncertainties of waste wood based energy. For this, different grades of waste wood and energy application have been investigated using lifecycle assessment. Sensitivity analysis has then been applied for supply chain processes and feedstock properties for the main emission contributing categories: transport, processing, pelletizing, urea resin fraction and related N 2 O formation. The results show, depending on the waste wood grade, the conversion option, scale and the related reference case, that emission reductions of up to 91% are possible for non-treated wood waste. Compared to this, energy from treated wood waste with low contamination can achieve up to 83% emission savings, similar to untreated waste wood pellets, but in some cases emissions from waste wood based energy can exceed the ones of the fossil fuel reference - in the worst case by 126%. Emission reductions from highly contaminated feedstocks are largest when replacing electricity from large-scale coal and landfill. The highest emission uncertainties are related to the wood's resin fraction and N 2 O formation during combustion and, pelletizing. Comparing wood processing with diesel and electricity powered equipment also generated high variations in the results, while emission variations related to transport are relatively small. Using treated waste wood as a bioenergy feedstock can be a valid option to reduce emissions from energy production but this is only realisable if coal and landfill gas are replaced. To achieve meaningful emission reduction in line with national and international climate change targets, pre-treatment of waste wood would be required to reduce components that form N 2 O during the energy conversion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Household wood heater usage and indoor leakage of BTEX in Launceston, Australia: A null result

NASA Astrophysics Data System (ADS)

Galbally, Ian E.; Gillett, Robert W.; Powell, Jennifer C.; Lawson, Sarah J.; Bentley, Simon T.; Weeks, Ian A.

A study has been conducted in Launceston, Australia, to determine within households with wood heaters the effect of leakage from the heater and flue on the indoor air concentrations of the pollutants: benzene, toluene, ethylbenzene and xylene (BTEX). The study involved three classes: 28 households without wood heaters, 19 households with wood heaters compliant with the relevant Australian Standard and 30 households with non-compliant wood heaters. Outdoor and indoor BTEX concentrations were measured in each household for 7 days during summer when there was little or no wood heater usage, and for 7 days during winter when there was widespread wood heater usage. Each participant kept a household activity diary throughout their sampling periods. For wintertime, there were no significant differences of the indoor BTEX concentrations between the three classes of households. Also there were no significant relationships between BTEX indoor concentrations within houses and several measures of the amount of wood heater use within these houses. For the households sampled in this study, the use of a wood heater within a house did not lead to BTEX release within that house and had no direct detectable influence on the concentrations of BTEX within the house. We propose that the pressure differences associated with the both the leakiness or permeability of the building envelope and the draught of the wood heater have key roles in determining whether there will be backflow of smoke from the wood heater into the house. For a leaky house with a well maintained wood heater there should be no backflow of smoke from the wood heater into the house. However backflow of smoke may occur in well sealed houses. The study also found that wood heater emissions raise the outdoor concentrations of BTEX in winter in Launceston and through the mixing of outdoor air through the building envelopes into the houses, these emissions contribute to increases in the indoor concentrations of BTEX in winter in all houses in Launceston.

Recycling of wood for particle board production: accounting of greenhouse gases and global warming contributions.

PubMed

Merrild, Hanna; Christensen, Thomas H

2009-11-01

The greenhouse gas (GHG) emissions related to the recycling of wood waste have been assessed with the purpose to provide useful data that can be used in accounting of greenhouse gas emissions. Here we present data related to the activities in a material recovery facility (MRF) where wood waste is shredded and foreign objects are removed in order to produce wood chips for use in the production of particleboard. The data are presented in accordance with the UOD (upstream, operational, downstream) framework presented in Gentil et al. (Waste Management & Research, 27, 2009). The GHG accounting shows that the emissions related to upstream activities (5 to 41 kg CO(2)-equivalents tonne( -1) wood waste) and to activities at the MRF (approximately 5 kg CO(2)-equivalents tonne(-1) wood waste) are negligible compared to the downstream processing (-560 to -120 kg CO(2)equivalents tonne(-1) wood waste). The magnitude of the savings in GHG emissions downstream are mainly related to savings in energy consumption for drying of fresh wood for particleboard production. However, the GHG account highly depends on the choices made in the modelling of the downstream system. The inclusion of saved electricity from avoided chipping of virgin wood does not change the results radically (-665 to -125 kg CO(2)-equivalents tonne(- 1) wood waste). However, if in addition it is assumed that the GHG emissions from combustion of wood has no global warming potential (GWP) and that the energy produced from excess wood due to recycling substitutes energy from fossil fuels, here assumed to be coal, potentially large downstream GHG emissions savings can be achieved by recycling of waste wood (-1.9 to -1.3 tonnes CO(2)-equivalents tonne(- 1) wood waste). As the data ranges are broad, it is necessary to carefully evaluate the feasibility of the data in the specific system which the GHG accounting is to be applied to.

Application of FTIR spectroscopy to the characterization of archeological wood.

PubMed

Traoré, Mohamed; Kaal, Joeri; Martínez Cortizas, Antonio

2016-01-15

Two archeological wood samples were studied by attenuated total reflectance Fourier transform infrared (FTIR-ATR) spectroscopy. They originate from a shipwreck in Ribadeo Bay in the northwest of Spain and from a beam wood of an old nave of the Cathedral of Segovia in the central Spain. Principal component analysis was applied to the transposed data matrix (samples as columns and spectral bands as rows) of 43 recorded spectra (18 in the shipwreck and 25 in the beam wood). The results showed differences between the two samples, with a larger proportion of carbohydrates and smaller proportion of lignin in the beam than in the shipwreck wood. Within the beam wood, lignin content was significantly lower in the recent than the old tree rings (P=0.005). These variations can be attributed to species differences between the two woods (oak and pine respectively), with a mixture of guaiacyl and syringyl in hardwood lignin, whereas softwood lignin consists almost exclusively of guaiacyl moieties. The influence of environmental conditions on the FTIR fingerprint was probably reflected by enhanced oxidation of lignin in aerated conditions (beam wood) and hydrolysis of carbohydrates in submerged-anoxic conditions (shipwreck wood). Molecular characterization by analytical pyrolysis of selected samples from each wood type confirmed the interpretation of the mechanisms behind the variability in wood composition obtained by the FTIR-ATR. Copyright © 2015 Elsevier B.V. All rights reserved.

Temporal Trend in Wood Dust Exposure During the Production of Wood Pellets.

PubMed

Eriksson, Kåre; Bryngelsson, Ing-Liss; Hagström, Katja

2017-05-01

Wood dust data collected in the production of wood pellets during 2001 to 2013 were evaluated to study a temporal trend in inhalation exposure. A linear mixed effects model of natural ln-transformed data was used to express the relative annual difference in inhalation wood dust exposure. There was an annual decrease of -20.5% of the geometric mean wood dust exposure during 2001 until 2013. The results were based on 617 inhalable dust samples collected at 14 different production units. The exposure to wood dust at the industrial premises investigated has decreased from a relatively high level of 6.4 mg m-3 in 2001 to 1.0 mg-3 in 2013. The Swedish Occupational Exposure Limit (SOEL) of 2 mg m-3 may still be exceeded. Analysis of the temporal trend in soft wood production units revealed declines in exposure of 20.5% per annum. It is important that precautions are taken to protect workers from a hazardous exposure to wood dust at the premises as the SOEL of 2 mg m-3 at some occasions is still exceeded. Additional measurements of wood dust exposure should be carried out on a regular basis in wood pellet production units in Sweden as well in other countries. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Application of FTIR spectroscopy to the characterization of archeological wood

NASA Astrophysics Data System (ADS)

Traoré, Mohamed; Kaal, Joeri; Martínez Cortizas, Antonio

2016-01-01

Two archeological wood samples were studied by attenuated total reflectance Fourier transform infrared (FTIR-ATR) spectroscopy. They originate from a shipwreck in Ribadeo Bay in the northwest of Spain and from a beam wood of an old nave of the Cathedral of Segovia in the central Spain. Principal component analysis was applied to the transposed data matrix (samples as columns and spectral bands as rows) of 43 recorded spectra (18 in the shipwreck and 25 in the beam wood). The results showed differences between the two samples, with a larger proportion of carbohydrates and smaller proportion of lignin in the beam than in the shipwreck wood. Within the beam wood, lignin content was significantly lower in the recent than the old tree rings (P = 0.005). These variations can be attributed to species differences between the two woods (oak and pine respectively), with a mixture of guaiacyl and syringyl in hardwood lignin, whereas softwood lignin consists almost exclusively of guaiacyl moieties. The influence of environmental conditions on the FTIR fingerprint was probably reflected by enhanced oxidation of lignin in aerated conditions (beam wood) and hydrolysis of carbohydrates in submerged-anoxic conditions (shipwreck wood). Molecular characterization by analytical pyrolysis of selected samples from each wood type confirmed the interpretation of the mechanisms behind the variability in wood composition obtained by the FTIR-ATR.

Effect of Trichoderma-enriched organic charcoal in the integrated wood protection strategy

PubMed Central

Gandía, Mónica; Marcos, Jose F.; Bas, Maria del Carmen; Fink, Siegfried

2017-01-01

The gradual elimination of chromium from wood preservative formulations results in higher Cu leaching and increased susceptibility to wood decay fungi. Finding a sustainable strategy in wood protection has become of great interest among researchers. The objective of these in vitro studies was to demonstrate the effect of T-720-enriched organic charcoal (biochar) against five wood decay basidiomycetes isolated from strongly damaged poles. For this purpose, the antagonistic potential of Trichoderma harzianum (strain T-720) was confirmed among other four Trichoderma spp. against five brown-rot basidiomycetes in dual culture tests. T-720 was genetically transformed and tagged with the green fluorescent protein (GFP) in order to study its antagonistic mechanism against wood decay basidiomycetes. It was also demonstrated that T-720 inhibits the oxalic acid production by basidiomycetes, a well-known mechanism used by brown-rot fungi to detoxify Cu from impregnated wood. Additionally, this study evaluated the effect of biochar, alone or in combination with T-720, on Cu leaching by different preservatives, pH stabilization and prevention of wood decay caused by five basidiomycetes. Addition of biochar resulted in a significant Cu binding released from impregnated wood specimens. T-720-enriched biochar showed a significant reduction of wood decay caused by four basidiomycetes. The addition of T-720-enriched biochar to the soil into which utility poles are placed may improve the efficiency of Cr-free wood preservatives. PMID:28797118

Wood and Sediment Dynamics in River Corridors

NASA Astrophysics Data System (ADS)

Wohl, E.; Scott, D.

2015-12-01

Large wood along rivers influences entrainment, transport, and storage of mineral sediment and particulate organic matter. We review how wood alters sediment dynamics and explore patterns among volumes of instream wood, sediment storage, and residual pools for dispersed pieces of wood, logjams, and beaver dams. We hypothesized that: volume of sediment per unit area of channel stored in association with wood is inversely proportional to drainage area; the form of sediment storage changes downstream; sediment storage correlates most strongly with wood load; and volume of sediment stored behind beaver dams correlates with pond area. Lack of data from larger drainage areas limits tests of these hypotheses, but analyses suggest a negative correlation between sediment volume and drainage area and a positive correlation between wood and sediment volume. The form of sediment storage in relation to wood changes downstream, with wedges of sediment upstream from jammed steps most prevalent in small, steep channels and more dispersed sediment storage in lower gradient channels. Use of a published relation between sediment volume, channel width, and gradient predicted about half of the variation in sediment stored upstream from jammed steps. Sediment volume correlates well with beaver pond area. Historically more abundant instream wood and beaver populations likely equated to greater sediment storage within river corridors. This review of the existing literature on wood and sediment dynamics highlights the lack of studies on larger rivers.

Influence of corn steep liquor and glucose on colonization of control and CCB (Cu/Cr/B)-treated wood by brown rot fungi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Humar, Miha; Amartey, Sam A.; Pohleven, Franc

2006-07-01

There are increasing problems with regard to the disposal of treated wood waste. Due to heavy metals or arsenic in impregnated wood waste, burning and landfill disposal options are not considered to be environmentally friendly solutions for dealing with this problem. Extraction of the heavy metals and recycling of the preservatives from the wood waste is a much more promising and environmentally friendly solution. In order to study the scale up of this process, copper/chromium/boron-treated wood specimens were exposed to copper tolerant (Antrodia vaillantii and Leucogyrophana pinastri) and copper sensitive wood decay fungi (Gloeophyllum trabeum and Poria monticola). Afterwards, themore » ability of fungal hyphae to penetrate and overgrow the wood specimens was investigated. The fungal growths were stimulated by immersing the specimens into aqueous solution of glucose or corn steep liquor prior to exposure to the fungi. The fastest colonization of the impregnated wood was by the copper tolerant A. vaillantii. Addition of glucose onto the surface of the wood specimens increased the fungi colonization of the specimens; however, immersion of the specimens into the solution of corn steep liquor did not have the same positive influence. These results are important in elucidating copper toxicity in wood decay fungi and for using these fungi for bioremediation of treated wood wastes.« less

Effect of Trichoderma-enriched organic charcoal in the integrated wood protection strategy.

PubMed

Ribera, Javier; Gandía, Mónica; Marcos, Jose F; Bas, Maria Del Carmen; Fink, Siegfried; Schwarze, Francis W M R

2017-01-01

The gradual elimination of chromium from wood preservative formulations results in higher Cu leaching and increased susceptibility to wood decay fungi. Finding a sustainable strategy in wood protection has become of great interest among researchers. The objective of these in vitro studies was to demonstrate the effect of T-720-enriched organic charcoal (biochar) against five wood decay basidiomycetes isolated from strongly damaged poles. For this purpose, the antagonistic potential of Trichoderma harzianum (strain T-720) was confirmed among other four Trichoderma spp. against five brown-rot basidiomycetes in dual culture tests. T-720 was genetically transformed and tagged with the green fluorescent protein (GFP) in order to study its antagonistic mechanism against wood decay basidiomycetes. It was also demonstrated that T-720 inhibits the oxalic acid production by basidiomycetes, a well-known mechanism used by brown-rot fungi to detoxify Cu from impregnated wood. Additionally, this study evaluated the effect of biochar, alone or in combination with T-720, on Cu leaching by different preservatives, pH stabilization and prevention of wood decay caused by five basidiomycetes. Addition of biochar resulted in a significant Cu binding released from impregnated wood specimens. T-720-enriched biochar showed a significant reduction of wood decay caused by four basidiomycetes. The addition of T-720-enriched biochar to the soil into which utility poles are placed may improve the efficiency of Cr-free wood preservatives.

Comparative evaluation of different thermally modified wood samples finishing with UV-curable and waterborne coatings

NASA Astrophysics Data System (ADS)

Herrera, René; Muszyńska, Monika; Krystofiak, Tomasz; Labidi, Jalel

2015-12-01

Thermally modified wood has been developed as an industrial method to improve durability and dimensional stability of wood and thus extends the range of uses and service life of wood-based products. Despite the improvements gained by treatment, surface finishing using coatings prevents esthetical changes such as color degradation or occasional growth of mold adding protection in outdoor use and extending the service life of products. The wood finishing process was carried out with commercially available waterborne and UV-curable coatings on industrially modified at 192, 200, 212 °C and unmodified European ash (Fraxinus excelsior L.) wood, using an industrial rollers system and a laboratory brushing system. Changes caused by thermal treatment which could affect the surface finish were measured and compared with control samples, such as water uptake, wettability and acidity. Following the wood finishing, surface properties and esthetic changes were evaluated; as well as the coatings performance. Thermally modified wood presented improved adherence compared with unmodified wood with a significant improvement in samples modified at 212 °C, which also present the highest hardness when UV-cured. Finishes with UV-curing maintain the hydrophobic effect of thermally modified wood, whereas waterborne finishes increase the surface wettability. Thermal modification did not negatively influence on the elastic properties of the coated substrate and thus allows this material to be finished with different coating systems in the same conditions as unmodified wood.

From Wood to Textiles: Top-Down Assembly of Aligned Cellulose Nanofibers.

PubMed

Jia, Chao; Chen, Chaoji; Kuang, Yudi; Fu, Kun; Wang, Yilin; Yao, Yonggang; Kronthal, Spencer; Hitz, Emily; Song, Jianwei; Xu, Fujun; Liu, Boyang; Hu, Liangbing

2018-06-07

Advanced textiles made of macroscopic fibers are usually prepared from synthetic fibers, which have changed lives over the past century. The shortage of petrochemical resources, however, greatly limits the development of the textile industry. Here, a facile top-down approach for fabricating macroscopic wood fibers for textile applications (wood-textile fibers) comprising aligned cellulose nanofibers directly from natural wood via delignification and subsequent twisting is demonstrated. Inherently aligned cellulose nanofibers are well retained, while the microchannels in the delignified wood are squeezed and totally removed by twisting, resulting in a dense structure with approximately two times higher mechanical strength (106.5 vs 54.9 MPa) and ≈20 times higher toughness (7.70 vs 0.36 MJ m -3 ) than natural wood. Dramatically different from natural wood, which is brittle in nature, the resultant wood-textile fibers are highly flexible and bendable, likely due to the twisted structures. The wood-textile fibers also exhibit excellent knitting properties and dyeability, which are critical for textile applications. Furthermore, functional wood-textile fibers can be achieved by preinfiltrating functional materials in the delignified wood film before twisting. This top-down approach of fabricating aligned macrofibers is simple, scalable, and cost-effective, representing a promising direction for the development of smart textiles and wearable electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nitrogen removal in wood chip combined substrate baffled subsurface-flow constructed wetlands: impact of matrix arrangement and intermittent aeration.

PubMed

Li, Huai; Chi, Zifang; Yan, Baixing; Cheng, Long; Li, Jianzheng

2017-02-01

In this study, two lab-scale baffled subsurface-flow constructed wetlands (BSFCWs), including gravel-wood chips-slag and gravel-slag-wood chips, were operated at different intermittent aeration to evaluate the effect of artificial aeration and slow-released carbon source on the treatment efficiency of high-strength nitrogen wastewater. Results indicated that gravel-slag-wood chips extended aerobic/anaerobic alternating environment to gravel and slag zones and maintained anaerobic condition in the subsequent wood chip section. The order of gravel-slag-wood chip was more beneficial to pollutant removal. Sufficient carbon source supply resulted from wood-chip-framework substrate simultaneously obtained high removals of COD (97%), NH 4 + -N (95%), and TN (94%) in BSFCWs at 2 h aeration per day. The results suggest that intermittent aeration combined with wood chips could achieve high nitrogen removal in BSFCWs.

A comparison of the recoverable proportion of methicillin-resistant Staphylococcus aureus from two different types of papers.

PubMed

Kacmaz, Birgul; Gul, Serdar

2016-01-01

Paper is used for various purposes in hospitals. Generally, there are two different types of paper, which are commonly used in our facility: wood-free paper, and paper containing wood. We compared the recoverable proportion of methicillin-resistant Staphylococcus aureus (MRSA; ATCC 43300) from the surface of such papers. The papers were divided into two groups: Group 1: wood-free paper; Group 2: paper containing wood. The papers were contaminated in a standardized procedure with 0.1 mL of a 5×10(7) CFU MRSA/mL stock solution. The recoverable proportion of MRSA was higher in the wood-containing papers than in the papers without wood (P=0.043). This study indicates that if paper is purchased for healthcare facilities it should not contain wood, but rather wood-free paper types should be considered.

Weathering Characteristics of Wood Plastic Composites Reinforced with Extracted or Delignified Wood Flour

PubMed Central

Chen, Yao; Stark, Nicole M.; Tshabalala, Mandla A.; Gao, Jianmin; Fan, Yongming

2016-01-01

This study investigated weathering performance of an HDPE wood plastic composite reinforced with extracted or delignified wood flour (WF). The wood flour was pre-extracted with three different solvents, toluene/ethanol (TE), acetone/water (AW), and hot water (HW), or sodium chlorite/acetic acid. The spectral properties of the composites before and after artificial weathering under accelerated conditions were characterized by Fourier transform infrared (FTIR) spectroscopy, the surface color parameters were analyzed using colorimetry, and the mechanical properties were determined by a flexural test. Weathering of WPC resulted in a surface lightening and a decrease in wood index (wood/HDPE) and flexural strength. WPCs that were reinforced with delignified wood flour showed higher ΔL* and ΔE* values, together with lower MOE and MOR retention ratios upon weathering when compared to those with non-extracted control and extracted WF. PMID:28773732

Age-dependent radial increases in wood specific gravity of tropical pioneers in Costa Rica

Treesearch

Bruce G. Williamson; Michael C. Wiemann

2010-01-01

Wood specific gravity is the single best descriptor of wood functional properties and tree life-history traits, and it is the most important variable in estimating carbon stocks in forests. Tropical pioneer trees produce wood of increasing specific gravity across the trunk radius as they grow in stature. Here, we tested whether radial increases in wood specific gravity...

Moisture properties

Treesearch

Roger M. Rowell

2005-01-01

Wood was designed by nature over millions of years to perform in a wet environment. The wood structure is formed in a water-saturated environment in the living tree, and the water in the living tree keeps the wood elastic and able to withstand environmental strain such as high wind loads. We cut down a tree, dry the wood, and mainly use it in its dry state. But wood in...

Science supporting the economic and environmental benefits of using wood and wood products in green building construction

Treesearch

Michael A. Ritter; Kenneth Skog; Richard Bergman

2011-01-01

The objective of this report is to summarize the scientific findings that support the environmental and economic benefits of using wood and wood products in green building construction. Despite documented advantages in many peer-reviewed scientific articles, most building professionals and members of the public do not recognize wood as a renewable resource or the role...

Periodate and hypobromite modification of Southern pine wood to improve sorption of copper ion

Treesearch

James D. McSweeny; Roger M. Rowell; George C. Chen; Thomas L. Eberhardt; Min Soo-Hong

2008-01-01

Milled southern pine wood was modified with sequential treatments of sodium periodate and sodium hypobromite for the purpose of improving copper ion (Cu2+) sorption capacity of the wood when tested in 24-h equilibrium batch tests. The modified wood provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ uptake over that of...

Statistical analysis of influence of soil source on leaching of arsenic and copper from CCA-C treated wood

Treesearch

Patricia Lebow; Richard Ziobro; Linda Sites; Tor Schultz; David Pettry; Darrel Nicholas; Stan Lebow; Pascal Kamdem; Roger Fox; Douglas Crawford

2006-01-01

Leaching of wood preservatives affects the long-term efficacy and environmental impact of treated wood. Soil properties and wood characteristicscan affectleaching of woad preservatives, but these effects are not well understood. This paper reports a statistical analysis of the effects of soil and wood properties on leaching of arsenic (As) and copper (Cu) from southern...

Corrosion of metals in treated wood examined by synchrotron based xanes and XFM

Treesearch

Samuel L. Zelinka; Joseph E. Jakes; Grant T. Kirker; Leandro Passarini; Barry Lai

2016-01-01

Copper based waterborne wood preservatives are frequently used to extend the service life of wood products used in outdoor environments. While these copper based treatments protect the wood from fungal decay and insect attack, they increase the corrosion of metals embedded or in contact with the treated wood. Over the past ten years, several studies have looked at the...

Synchrotron based x-ray fluorescence microscopy confirms copper in the corrosion products of metals in contact with treated wood

Treesearch

Samuel L. Zelinka; Joseph E. Jakes; Grant T. Kirker; David Vine; Stefan Vogt

2017-01-01

Copper based waterborne wood preservatives are frequently used to extend the service life of wood products when subjected to frequent moisture exposure. While these copper based treatments protect the wood from fungal decay and insect attack, they increase the corrosion of metals embedded or in contact with the treated wood. Previous research has shown the most...

Treated wood in transition : a look at CCA and the candidates to replace it

Treesearch

Stan Lebow; Jerrold Winandy; Donald Bender

2003-01-01

Wood is one of the most versatile and widely used building materials. However, it is also biodegradable, and may be attacked by decay fungi or insects when used in some applications or geographic locations. Uses that allow the wood to frequently become wet, such as embedded posts or other exposed wood members, are familiar examples of applications where wood will...

Treated wood in transition : a look at CCA and the candidates to replace it

Treesearch

Stan Lebow; Jerrold Winandy; Donald Bender

2004-01-01

Wood is one of the most versatile and widely used building materials. However, it is also biodegradable and may be attacked by decay fungi or insects when used in some applications or geographic locations. Uses that allow the wood to frequently become wet, such as embedded posts or other exposed wood members, are familiar examples of applications where wood will...

Methods for Mitigating the Environmental Risks Associated with Wood Preservatives

Treesearch

Dennis Hayward; Stan T. Lebow; Kenneth M. Brooks

2011-01-01

As noted in earlier chapters, the treatment of wood is both art and science. Wood is a variable material; treatment results tend to vary with the preservative and wood species and even within boards of the same species. This means that treated wood often contains a range of preservative retentions. Some pieces will have less than the desired retention, while others may...

Wood-based composite materials : panel products, glued-laminated timber, structural composite lumber, and wood-nonwood composite materials

Treesearch

Nicole M. Stark; Zhiyong Cai; Charles Carll

2010-01-01

This chapter gives an overview of the general types and composition of wood-based composite products and the materials and processes used to manufacture them. It describes conventional wood-based composite panels and structural composite materials intended for general construction, interior use, or both. This chapter also describes wood–nonwood composites. Mechanical...

Life cycle inventory of manufacturing prefinished engineered wood flooring in eastern U.S. with comparison to solid strip wood flooring

Treesearch

Richard D. Bergman; Scott A. Bowe

2011-01-01

Building products have come under increased scrutiny because of environmental impacts from their manufacture. Our study followed the life cycle inventory approach for prefinished engineered wood flooring in the eastern US and compared the results with those of solid strip wood flooring. Our study surveyed five engineered wood flooring manufacturers in the eastern US....

Fractionation of heavy metals in liquefied chromated copper arsenate (CCA)-treated wood sludge using a modified BCR-sequential extraction procedure

Treesearch

Hui Pan; Chung-Yun Hse; Robert Gambrell; Todd F. Shupe

2009-01-01

Chromated copper arsenate (CCA)-treated wood was liquefied with polyethylene glycol/glycerin and sulfuric acid. After liquefaction, most CCA metals (98% As, 92% Cr, and 83% Cu) were removed from liquefied CCA-treated wood by precipitation with calcium hydroxide. The original CCA-treated wood and liquefied CCA-treated wood sludge were fractionated by a modified...

Overview of the wood adhesives industry in China

Treesearch

Chung-Yun Hse

1999-01-01

Adhesives products and demand for them in China are discussed in this paper, with special emphasis on wood adhesives products in this decade. In 1994, the wood industries in China con­sumed more than 330,000 tons of adhesives. The estimated demand for wood adhesives will be more than 560,000 tons in the year 2000. The main wood adhesive used is urea-formaldehyde resin...

On the patterns and processes of wood in northern California streams

NASA Astrophysics Data System (ADS)

Benda, Lee; Bigelow, Paul

2014-03-01

Forest management and stream habitat can be improved by clarifying the primary riparian and geomorphic controls on streams. To this end, we evaluated the recruitment, storage, transport, and the function of wood in 95 km of streams (most drainage areas < 30 km2) in northern California, crossing four coastal to inland regions with different histories of forest management (managed, less-managed, unmanaged). The dominant source of variability in stream wood storage and recruitment is driven by local variation in rates of bank erosion, forest mortality, and mass wasting. These processes are controlled by changes in watershed structure, including the location of canyons, floodplains and tributary confluences; types of geology and topography; and forest types and management history. Average wood storage volumes in coastal streams are 5 to 20 times greater than inland sites primarily from higher riparian forest biomass and growth rates (productivity), with some influence by longer residence time of wood in streams and more wood from landsliding and logging sources. Wood recruitment by mortality (windthrow, disease, senescence) was substantial across all sites (mean 50%) followed by bank erosion (43%) and more locally by mass wasting (7%). The distances to sources of stream wood are controlled by recruitment process and tree height. Ninety percent of wood recruitment occurs within 10 to 35 m of channels in managed and less-managed forests and upward of 50 m in unmanaged Sequoia and coast redwood forests. Local landsliding extends the source distance. The recruitment of large wood pieces that create jams (mean diameter 0.7 m) is primarily by bank erosion in managed forests and by mortality in unmanaged forests. Formation of pools by wood is more frequent in streams with low stream power, indicating the further relevance of environmental context and watershed structure. Forest management influences stream wood dynamics, where smaller trees in managed forests often generate shorter distances to sources of stream wood, lower stream wood storage, and smaller diameter stream wood. These findings can be used to improve riparian protection and inform spatially explicit riparian management.

The Long-Term Effects of Large Wood Placement on Salmonid Habitat in East Fork Mill Creek, Redwood National and State Park, California

NASA Astrophysics Data System (ADS)

Rodriguez, D. L.; Stubblefield, A. P.

2017-12-01

The conservation and recovery of anadromous salmonids (Oncorhynchus sp.) depend on stream restoration and protection of freshwater habitats. Instream large wood dictates channel morphology, increase retention of terrestrial inputs such as organic matter, nutrients and sediment, and enhances the quality of fish habitat. Historic land use/land cover changes have resulted in aquatic systems devoid of this component. Restoration by placement of large wood jams is intended to restore physical and biological processes. An important question for scientists and managers, in addition to the initial effectiveness of restoration, is the persistence and fate of this type of project. In this study we compare channel change and large wood attributes on the East Fork of Mill Creek, a tributary of the Smith River in northern California, eight years after a major instream wood placement effort took place. Our results are compared with previously published data from before and one year after the restoration. Preliminary results suggest the dramatic increase in spawning gravel abundance and large wood accumulation observed in the earlier study have persisted. From 2008 to 2016 a reduction in median sediment size, ranging from 103-136 percent, has been observed in a majority of the sites. The sites have continued to grow in size and influence by racking floating wood from upstream and destabilizing proximate banks of riparian alder, increasing both instream large wood volume (5-196 %) and floodplain connectivity. Preliminary results also show a decrease in residual pool depth and an increase in pool length which may be attributed to floodplain connectivity. Changes to the following attributes are evaluated: 1) wood loading (total site wood volume, total wood volume in active channel, and wood piece count); 2) percent pool cover by large wood; 3) residual pool depth; 4) upstream sediment aggradation; 5) floodplain connectivity; and 6) mean sediment size directly above and below large wood. We present on these results and statistical comparisons of total site wood volume with response factors.

How to Make a Beetle Out of Wood: Multi-Elemental Stoichiometry of Wood Decay, Xylophagy and Fungivory

PubMed Central

Filipiak, Michał; Weiner, January

2014-01-01

The majority of terrestrial biomass is wood, but the elemental composition of its potential consumers, xylophages, differs hugely from that of wood. This causes a severe nutritional imbalance. We studied the stoichiometric relationships of 11 elements (C, N, P, K, Ca, Mg, Fe, Zn, Mn, Cu, Na) in three species of pine-xylem-feeding insects, Stictoleptura rubra, Arhopalus rusticus (Coleoptera, Cerambycidae) and Chalcophora mariana (Coleoptera, Buprestidae), to elucidate their mechanisms of tissue growth and to match their life histories to their dietary constraints. These beetles do not differ from other Coleoptera in their absolute elemental compositions, which are approximately 1000 (N), 100 (P, Cu) and 50 (K, Na) times higher than in dead but undecayed pine wood. This discrepancy diminishes along the wood decay gradient, but the elemental concentrations remain higher by an order of magnitude in beetles than in highly decayed wood. Numerical simulation of the life history of S. rubra shows that feeding on nutrient-poor undecayed wood would extend its development time to implausible values, whereas feeding on highly decomposed wood (heavily infected with fungi) would barely balance its nutritional budget during the long development period of this species. The changes in stoichiometry indicate that the relative change in the nutrient levels in decaying wood cannot be attributed solely to carbon loss resulting from decomposer respiration: the action of fungi substantially enriches the decaying wood with nutritional elements imported from the outside of the system, making it a suitable food for wood-eating invertebrates. PMID:25536334

Online sorting of recovered wood waste by automated XRF-technology: part II. Sorting efficiencies.

PubMed

Hasan, A Rasem; Solo-Gabriele, Helena; Townsend, Timothy

2011-04-01

Sorting of waste wood is an important process practiced at recycling facilities in order to detect and divert contaminants from recycled wood products. Contaminants of concern include arsenic, chromium and copper found in chemically preserved wood. The objective of this research was to evaluate the sorting efficiencies of both treated and untreated parts of the wood waste stream, and metal (As, Cr and Cu) mass recoveries by the use of automated X-ray fluorescence (XRF) systems. A full-scale system was used for experimentation. This unit consisted of an XRF-detection chamber mounted on the top of a conveyor and a pneumatic slide-way diverter which sorted wood into presumed treated and presumed untreated piles. A randomized block design was used to evaluate the operational conveyance parameters of the system, including wood feed rate and conveyor belt speed. Results indicated that online sorting efficiencies of waste wood by XRF technology were high based on number and weight of pieces (70-87% and 75-92% for treated wood and 66-97% and 68-96% for untreated wood, respectively). These sorting efficiencies achieved mass recovery for metals of 81-99% for As, 75-95% for Cu and 82-99% of Cr. The incorrect sorting of wood was attributed almost equally to deficiencies in the detection and conveyance/diversion systems. Even with its deficiencies, the system was capable of producing a recyclable portion that met residential soil quality levels established for Florida, for an infeed that contained 5% of treated wood. Copyright © 2010 Elsevier Ltd. All rights reserved.

How to make a beetle out of wood: multi-elemental stoichiometry of wood decay, xylophagy and fungivory.

PubMed

Filipiak, Michał; Weiner, January

2014-01-01

The majority of terrestrial biomass is wood, but the elemental composition of its potential consumers, xylophages, differs hugely from that of wood. This causes a severe nutritional imbalance. We studied the stoichiometric relationships of 11 elements (C, N, P, K, Ca, Mg, Fe, Zn, Mn, Cu, Na) in three species of pine-xylem-feeding insects, Stictoleptura rubra, Arhopalus rusticus (Coleoptera, Cerambycidae) and Chalcophora mariana (Coleoptera, Buprestidae), to elucidate their mechanisms of tissue growth and to match their life histories to their dietary constraints. These beetles do not differ from other Coleoptera in their absolute elemental compositions, which are approximately 1000 (N), 100 (P, Cu) and 50 (K, Na) times higher than in dead but undecayed pine wood. This discrepancy diminishes along the wood decay gradient, but the elemental concentrations remain higher by an order of magnitude in beetles than in highly decayed wood. Numerical simulation of the life history of S. rubra shows that feeding on nutrient-poor undecayed wood would extend its development time to implausible values, whereas feeding on highly decomposed wood (heavily infected with fungi) would barely balance its nutritional budget during the long development period of this species. The changes in stoichiometry indicate that the relative change in the nutrient levels in decaying wood cannot be attributed solely to carbon loss resulting from decomposer respiration: the action of fungi substantially enriches the decaying wood with nutritional elements imported from the outside of the system, making it a suitable food for wood-eating invertebrates.

Method for predicting dry mechanical properties from wet wood and standing trees

DOEpatents

Meglen, Robert R.; Kelley, Stephen S.

2003-08-12

A method for determining the dry mechanical strength for a green wood comprising: illuminating a surface of the wood to be determined with light between 350-2,500 nm, the wood having a green moisture content; analyzing the surface using a spectrometric method, the method generating a first spectral data, and using a multivariate analysis to predict the dry mechanical strength of green wood when dry by comparing the first spectral data with a calibration model, the calibration model comprising a second spectrometric method of spectral data obtained from a reference wood having a green moisture content, the second spectral data correlated with a known mechanical strength analytical result obtained from a reference wood when dried and having a dry moisture content.

Biodeterioration of wood

Treesearch

Carol A. Clausen

2010-01-01

Under proper conditions, wood will give centuries of service. However, under conditions that permit the development of wood-degrading organisms, protection must be provided during processing, merchandising, and use. The organisms that can degrade wood are principally fungi, insects, bacteria, and marine borers.

76 FR 71922 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-21

... from coatings and strippers used on wood products, wood paneling, and miscellaneous metal parts and...: PCAPCD Rule 236 (Wood Products and Coating Operations), PCAPCD Rule 238 (Factory Coating of Flat Wood...

Interannual kinetics (2010-2013) of large wood in a river corridor exposed to a 50-year flood event and fluvial ice dynamics

NASA Astrophysics Data System (ADS)

Boivin, Maxime; Buffin-Bélanger, Thomas; Piégay, Hervé

2017-02-01

Semi-alluvial rivers of the Gaspé Peninsula, Québec, are prone to produce and transport vast quantities of large wood (LW). The high rate of lateral erosion owing to high energy flows and noncohesive banks is the main process leading to the recruitment of large wood, which in turn initiates complex patterns of wood accumulation and reentrainment within the active channel. The delta of the Saint-Jean River (SJR) has accumulated large annual wood fluxes since 1960 that culminated in a wood raft of > 3-km in length in 2014. To document the kinetics of large wood on the main channel of SJR, four annual surveys were carried out from 2010 to 2013 to locate and describe > 1000 large wood jams (LWJ) and 2000 large wood individuals (LWI) along a 60-km river section. Airborne and ground photo/video images were used to estimate the wood volume introduced by lateral erosion and to identify local geomorphic conditions that control wood mobility and deposits. Video camera analysis allowed the examination of transport rates from three hydrometeorological events for specific river sections. Results indicate that the volume of LW recruited between 2010 and 2013 represents 57% of the total LW production over the 2004-2013 period. Volumes of wood deposited along the 60-km section were four times higher in 2013 than in 2010. Increases in wood amount occurred mainly in upper alluvial sections of the river, whereas decreases were observed in the semi-alluvial middle sections. Observations suggest that the 50-year flood event of 2010 produced large amounts of LW that were only partly exported out of the basin so that a significant amount was still available for subsequent floods. Large wood storage continued after this flood until a similar flood or an ice-breakup event could remobilise these LW accumulations into the river corridor. Ice-jam floods transport large amounts of wood during events with fairly low flow but do not contribute significantly to recruitment rates (ca. 10 to 30% early). It is fairly probable that the wood export peak observed in 2012 at the river mouth, where no flood occurred and which is similar to the 1-in 10-year flood of 2010, is mainly linked to such ice-break events that occurred in March 2012.

Wood mimetic hydrogel beads for enzyme immobilization.

PubMed

Park, Saerom; Kim, Sung Hee; Won, Keehoon; Choi, Joon Weon; Kim, Yong Hwan; Kim, Hyung Joo; Yang, Yung-Hun; Lee, Sang Hyun

2015-01-22

Wood component-based composite hydrogels have potential applications in biomedical fields owing to their low cost, biodegradability, and biocompatibility. The controllable properties of wood mimetic composites containing three major wood components are useful for enzyme immobilization. Here, lipase from Candida rugosa was entrapped in wood mimetic beads containing cellulose, xylan, and lignin by dissolving wood components with lipase in [Emim][Ac], followed by reconstitution. Lipase entrapped in cellulose/xylan/lignin beads in a 5:3:2 ratio showed the highest activity; this ratio is very similar to that in natural wood. The lipase entrapped in various wood mimetic beads showed increased thermal and pH stability. The half-life times of lipase entrapped in cellulose/alkali lignin hydrogel were 31- and 82-times higher than those of free lipase during incubation under denaturing conditions of high temperature and low pH, respectively. Owing to their biocompatibility, biodegradability, and controllable properties, wood mimetic hydrogel beads can be used to immobilize various enzymes for applications in the biomedical, bioelectronic, and biocatalytic fields. Copyright © 2014 Elsevier Ltd. All rights reserved.

Eco-friendly materials for large area piezoelectronics: self-oriented Rochelle salt in wood

NASA Astrophysics Data System (ADS)

Lemaire, E.; Ayela, C.; Atli, A.

2018-02-01

Upgraded biodegradable piezoelectric composite materials elaborated by incorporation of Rochelle salt (RS, Sodium potassium tartrate tetrahydrate) in wood were reported. RS crystals, known as the first discovered piezoelectric material, were grown in the micro-cavities of wood, having naturally a tubular structure, by soaking the wood into RS saturated water. Since most of the cavities in wood are oriented in the same direction, the piezoelectric effect was improved when the cavities were filled by RS crystals. The mechanical, structural and piezoelectric properties of RS incorporated wood composite samples were characterized. Both direct and converse piezoelectric effects are illustrated. The wood-base composite exhibits an effective piezoelectric constant d 33 of 11 pC N-1. Also, the flexural strength and modulus of elasticity were enhanced by inserting RS into the wood, nevertheless the samples became more brittle. The wood-based piezoelectric samples prepared in this work can be used as actuators, sensors or energy harvesters. The process developed here permits us to manufacture large area piezoelectric devices which are environmentally and economically unsurpassed.

Effect of stacking sequence on mechanical properties neem wood veneer plastic composites

NASA Astrophysics Data System (ADS)

Nagamadhu, M.; Kumar, G. C. Mohan; Jeyaraj, P.

2018-04-01

This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0°/0° WPC shows highest mechanical properties as compared to other sequences (90°/90°, 0°/90°, 45°/90°, 45°/45°). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images.

Five New Wood Decay Fungi (Polyporales and Hymenochaetales) in Korea.

PubMed

Kim, Nam Kyu; Park, Jae Young; Park, Myung Soo; Lee, Hyun; Cho, Hae Jin; Eimes, John A; Kim, Changmu; Lim, Young Woon

2016-09-01

The wood decay fungi are a diverse taxonomic group that plays a pivotal role in forest carbon cycling. Wood decay fungi use various enzymatic pathways to digest dead or living wood in order to obtain carbon and other nutrients and these enzymatic systems have been exploited for both industrial and medical applications. Over 600 wood decay fungi species have been described in Korea; however, the recent application of molecular markers has dramatically altered the taxonomy of many of these wood decay fungi at both the genus and species levels. By combining molecular methods, specifically sequences of the internal transcribed spacer region, with traditional morphological characters, this study identified five new species records for Korea in five genera: Aurantiporus , Favolus , Neofavolus , Loweomyces , and Hymenochaetopsis . Three of these genera ( Aurantiporus , Favolus , and Loweomyces ) were previously unknown in Korea. The relatively simple morphology of the wood decay fungi often leads to ambiguous taxonomic assignment. Therefore, molecular markers are a necessary component of any taxonomic or evolutionary study of wood decay fungi. Our study highlights the need for a more robust and multifaceted approach in investigating new wood decay fungi in Korea.

Microwave-assisted liquefaction of wood with polyhydric alcohols and its application in preparation of polyurethane (PU) foams

Treesearch

Hui Pan; Zhifeng Zheng; Chung Y. Hse

2011-01-01

Microwave radiation was used as the heating source in southern pine wood liquefaction with PEG/glycerin binary solvent. It was found that microwave heating was more efficient than conventional oil bath heating for wood liquefaction. The wood residue content of the H2SO4 catalyzed liquefied wood dropped to zero within 5 min with microwave heating. The resulting...

Microwave-assisted liquefaction of wood with polyhydric alcohols and its application in preparation of polyurethane (PU) foams

Treesearch

Hui Pan; Zhifeng Zheng; Chung-Yun Hse

2012-01-01

Microwave radiation was used as the heating source in southern pine wood liquefaction with PEG/ glycerin binary solvent. It was found that microwave heating was more efficient than conventional oil bath heating for wood liquefaction. The wood residue content of the H2SO4 catalyzed liquefied wood dropped to zero within 5 min with microwave heating. The resulting...

Biocentricity and economy of scale : hypothesis (and product) testing when wood is a part of an experimental system evaluating durability

Treesearch

Alex C. Wiedenhoeft

2009-01-01

Wood is a biological material, and its structure and organization are relicts of its biogenesis. From the hydrogen bonding of water molecules in the cell wall to extractives bleeding from knots in siding, the characteristics and behavior of wood are derived from its biological origin; this is my unashamedly biocentric view of wood structure. The structure of wood...

Surface chemistry changes of weathered HDPE/wood-flour composites studied by XPS and FTIR spectroscopy

Treesearch

Nicole M. Stark; Laurent M. Matuana

2004-01-01

The use of wood-derived fillers by the thermoplastic industry has been growing, fueled in part by the use of wood-fiber–thermoplastic composites by the construction industry. As a result, the durability of wood-fiber– thermoplastic composites after ultraviolet exposure has become a concern. Samples of 100% high-density polyethylene (HDPE) and HDPE filled with 50% wood-...

Outlook for U.S. paper and paperboard sector and wood fiber supply in North America

Treesearch

Peter J. Ince

2000-01-01

Consumption of wood fiber in pulp, paper and paperboard increased in the United States over the past century and is projected to increase well into the next century at a decelerating rate of growth. Harvest of pulpwood on forest land is the single largest source of wood fiber, followed by recycled paper and wood residues. In the past decade, wood residues declined in...

Treatment of wood with glucose-diammonium phosphate for fire and fungal decay protection

Treesearch

George C. Chen

2002-01-01

This study describes a method for dual protection of wood against fungal and fire degradation in one treatment. The method consists of impregnating wood with aqueous solution of glucose-diammonium phosphate at pH 9, followed by heating the treated wood at temperatures of 160 °C and 190 °C for various lengths of time to form water insoluble products in wood.

Effectiveness of the International Phytosanitary Standard ISPM No. 15 on reducing wood borer infestation rates in wood packaging material entering the United States

Treesearch

Robert A. Haack; Kerry O. Britton; Eckelhard G. Brockerhoff; Joseph F. Cavey; Lynn J. Garrett; Mark Kimberley; Frank Lowenstein; Amelia Nuding; Lars J. Olson; James Tumer; Kathryn N. Vasilaky

2014-01-01

Numerous bark- and wood-infesting insects have been introduced to new countries by international trade where some have caused severe environmental and economic damage. Wood packaging material (WPM), such as pallets, is one of the high risk pathways for the introduction of wood pests. International recognition of this risk resulted in adoption of International Standards...

Influence of carbonization conditions on the pyrolytic carbon deposition in acacia and eucalyptus wood chars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, M.; Gupta, R.C.

1997-04-01

The amount of deposited pyrolytic carbon (resulting from the cracking of volatile matter) was found to depend on wood species and carbonization conditions, such as temperature and heating rate. Maximum pyrolytic carbon deposition in both the acacia and eucalyptus wood chars has been observed at a carbonization temperature of 800 C. Rapid carbonization (higher heating rate) of wood significantly reduces the amount of deposited pyrolytic carbon in resulting chars. Results also indicate that the amount of deposited pyrolytic carbon in acacia wood char is less than that in eucalyptus wood char.

Investigating the molecular underpinnings underlying morphology and changes in carbon partitioning during tension wood formation in Eucalyptus.

PubMed

Mizrachi, Eshchar; Maloney, Victoria J; Silberbauer, Janine; Hefer, Charles A; Berger, Dave K; Mansfield, Shawn D; Myburg, Alexander A

2015-06-01

Tension wood has distinct physical and chemical properties, including altered fibre properties, cell wall composition and ultrastructure. It serves as a good system for investigating the genetic regulation of secondary cell wall biosynthesis and wood formation. The reference genome sequence for Eucalyptus grandis allows investigation of the global transcriptional reprogramming that accompanies tension wood formation in this global wood fibre crop. We report the first comprehensive analysis of physicochemical wood property changes in tension wood of Eucalyptus measured in a hybrid (E. grandis × Eucalyptus urophylla) clone, as well as genome-wide gene expression changes in xylem tissues 3 wk post-induction using RNA sequencing. We found that Eucalyptus tension wood in field-grown trees is characterized by an increase in cellulose, a reduction in lignin, xylose and mannose, and a marked increase in galactose. Gene expression profiling in tension wood-forming tissue showed corresponding down-regulation of monolignol biosynthetic genes, and differential expression of several carbohydrate active enzymes. We conclude that alterations of cell wall traits induced by tension wood formation in Eucalyptus are a consequence of a combination of down-regulation of lignin biosynthesis and hemicellulose remodelling, rather than the often proposed up-regulation of the cellulose biosynthetic pathway. © 2014 University of Pretoria New Phytologist © 2014 New Phytologist Trust.

Assemblage composition of fungal wood-decay species has a major influence on how climate and wood quality modify decomposition.

PubMed

Venugopal, Parvathy; Junninen, Kaisa; Edman, Mattias; Kouki, Jari

2017-03-01

The interactions among saprotrophic fungal species, as well as their interactions with environmental factors, may have a major influence on wood decay and carbon release in ecosystems. We studied the effect that decomposer diversity (species richness and assemblage composition) has on wood decomposition when the climatic variables and substrate quality vary simultaneously. We used two temperatures (16 and 21°C) and two humidity levels (70% and 90%) with two wood qualities (wood from managed and old-growth forests) of Pinus sylvestris. In a 9-month experiment, the effects of fungal diversity were tested using four wood-decaying fungi (Antrodia xantha, Dichomitus squalens, Fomitopsis pinicola and Gloeophyllum protractum) at assemblage levels of one, two and four species. Wood quality and assemblage composition affected the influence of climatic factors on decomposition rates. Fungal assemblage composition was found to be more important than fungal species richness, indicating that species-specific fungal traits are of paramount importance in driving decomposition. We conclude that models containing fungal wood-decay species (and wood-based carbon) need to take into account species-specific and assemblage composition-specific properties to improve predictive capacity in regard to decomposition-related carbon dynamics. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparison of VOC emissions between air-dried and heat-treated Norway spruce ( Picea abies), Scots pine ( Pinus sylvesteris) and European aspen ( Populus tremula) wood

NASA Astrophysics Data System (ADS)

Hyttinen, Marko; Masalin-Weijo, Marika; Kalliokoski, Pentti; Pasanen, Pertti

2010-12-01

Heat-treated wood is an increasingly popular decoration material. Heat-treatment improves dimensional stability of the wood and also prevents rot fungus growth. Although production of heat-treated wood has been rapidly increasing, there is only little information about the VOC emissions of heat-treated wood and its possible influences on indoor air quality. In the present study, VOC emissions from three untreated (air-dried) and heat-treated wood species were compared during a four weeks test period. It appeared that different wood species had clearly different VOC emission profiles. Heat-treatment was found to decrease VOC emissions significantly and change their composition. Especially, emissions of terpenes decreased from softwood samples and aldehydes from European aspen samples. Emissions of total aldehydes and organic acids were at the same level or slightly higher from heat treated than air-dried softwood samples. In agreement with another recent study, the emissions of furfural were found to increase and those of hexanal to decrease from all the wood species investigated. In contrast to air-dried wood samples, emissions of VOCs were almost in steady state from heat treated wood samples even in the beginning of the test.

Techno-economic analysis of wood biomass boilers for the greenhouse industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chau, J.; Sowlati, T.; Sokhansanj, Shahabaddine

2009-01-01

The objective of this study is to perform a techno-economic analysis on a typical wood pellet and wood residue boiler for generation of heat to an average-sized greenhouse in British Columbia. The variables analyzed included greenhouse size and structure, boiler efficiency, fuel types, and source of carbon dioxide (CO2) for crop fertilization. The net present value (NPV) show that installing a wood pellet or a wood residue boiler to provide 40% of the annual heat demand is more economical than using a natural gas boiler to provide all the heat at a discount rate of 10%. For an assumed lifespanmore » of 25 years, a wood pellet boiler system could generate NPV of C$259,311 without electrostatic precipitator (ESP) and C$74,695 with ESP, respectively. While, installing a wood residue boiler with or without an ESP could provide NPV of C$919,922 or C$1,104,538, respectively. Using a wood biomass boiler could also eliminate over 3000 tonne CO2 equivalents of greenhouse gases annually. Wood biomass combustion generates more particulate matters than natural gas combustion. However, an advanced emission control system could significantly reduce particulate matters emission from wood biomass combustion which would bring the particulate emission to a relatively similar level as for natural gas.« less

Efficacy of interventions targeting household air pollution from residential wood stoves.

PubMed

Ward, Tony J; Semmens, Erin O; Weiler, Emily; Harrar, Solomon; Noonan, Curtis W

2017-01-01

Wood is commonly used for residential heating, but there are limited evidence-based interventions for reducing wood smoke exposures in the indoor environment. The Asthma Randomized Trial of Indoor Wood Smoke (ARTIS) study was designed to assess the efficacy of residential interventions to reduce indoor PM exposure from wood stoves. As part of a three-arm randomized placebo-controlled trial, two household-level interventions were evaluated: wood stove changeouts and air filtration units. Exposure outcomes included indoor measures such as continuous PM 2.5 , particle counts, and carbon monoxide. Median indoor PM 2.5 concentration was 17.5 μg/m 3 in wood-burning homes prior to interventions. No significant reductions in PM 2.5 concentrations were observed in the 40 homes receiving the placebo filter intervention. Sixteen homes received the wood stove changeout and showed no significant changes in PM 2.5 or particle counts. PM 2.5 concentrations were reduced by 68% in the filter intervention homes. Relative to placebo, air filtration unit homes had an overall PM 2.5 reduction of 63% (95% CI: 47-75%). Relative to the wood stove changeout, the filtration unit intervention was more efficacious and less expensive, yet compliance issues indicated a need for the evaluation of additional strategies for improving indoor air quality in homes using wood stoves.

Desorption isotherms of heavy (AZOBE, EBONY) and light heavyweight tropical woods (IROKO, SAPELLI) of Cameroon

NASA Astrophysics Data System (ADS)

Nsouandélé, J. L.; Tamba, J. G.; Bonoma, B.

2018-04-01

This work is centered on the study of the desorption isotherms of heavy (Azobe, Ebony) and heavyweight (Iroko, Sapelli) tropical woods, which contribute in the determination of drying and storage of tropical plank woods. Desorption isotherms of tropical woods were experimentally determined under different temperatures in this study using the gravimetric method. The determination of Henderson's model isotherms parameters of desorption were obtained for temperatures of 20 °C, 30 °C, 40 °C, and 50 °C. The mean relative deviation between theoretical and experimental moisture contents was calculated and fitted well with the desorption models of tropical woods. We noticed that Henderson models fitted much better with experimental ones for 95% of relative humidity. The sigmoid shapes of results are satisfactory. Hysteresis phenomenon was observed for desorption isotherms of heavy (Azobe, Ebony) and heavyweight (Iroko, Sapelli) tropical woods. Results showed the difference between the stability and use of heavy and heavyweight tropical wood. These results help in the estimation of water content at equilibrium of tropical woods in relative humidity from experimented ones. Hygroscopic equilibrium humidity of heavy tropical woods varied between 0% and 50% while those of heavyweight varied between 0% and 25%. Therefore, these woods can be used in an opened environment; woodwork and decoration.

Corticosterone level and central dopaminergic activity involved in agile and exploratory behaviours in formosan wood mice (Apodemus semotus).

PubMed

Shieh, Kun-Ruey; Yang, Shu-Chuan

2018-03-27

The native Formosan wood mouse (Apodemus semotus) is the dominant rodent in Taiwan. In their natural environment, Formosan wood mice exhibit high locomotor activity, including searching and exploratory behaviours, which is observed similarly in the laboratory environment. How the behavioural responses of Formosan wood mice exhibit in elevated plus maze and marble burying tests remains unclear. How corticosterone levels and central dopaminergic activities are related to the behaviours in these tests is also unclear. This study compared the behaviours of Formosan wood mice with that of C57BL/6J mice using the elevated plus maze and marble burying tests, and measured the corticosterone levels and central dopaminergic activities. Formosan wood mice showed greater locomotor and exploratory activity than the C57BL/6J mice. Similarly, the marble burying and rearing numbers were higher for Formosan wood mice. High locomotor and exploratory behaviours were strongly correlated with corticosterone levels after acute mild restraint stress in Formosan wood mice. The anxiolytic, diazepam, reduced the high exploratory activity, corticosterone levels and central dopaminergic activities. The high locomotor and exploratory behaviours of Formosan wood mice are related to the corticosterone levels and central dopaminergic activities. These data may explain Formosan wood mice dominance in the intermediate altitude of Taiwan.

Energy and exergy analysis of cookstove by using Cedrus deodara (deodar wood) and saccharum officinarum (sugar cane) waste

NASA Astrophysics Data System (ADS)

Chouhan, A. P. Singh; Yaseen, S.; Pruthi, A.

2017-07-01

Deodar (Cedrus deodara) wood collected from the Kashmir region in India. This study is focused on energy and exergy analysis of cook stove by using deodar wood, demand of a cookstove is higher in rural areas. In ancient time U-shaped and three stone cook stove was used, but they emitted greenhouse gases CO and CO2 in the environment and these toxic emissions are also dangerous for human being and the environment. Sampada model cook stove used for the analysis of energy an exergy by using water boiling test with using deodar wood and bagasse samples and a mixture of wood and bagasse also used. Wood and bagasse characterized for the ultimate, proximate, calorific value before the water boiling test of the cookstove. Results carried out that the efficiency of cook stove with deodar wood was 33.33 % and exergy calculated 2.1 % and energy efficiency and energy efficiency by using bagasse were 23.23 % and 0.43 %, respectively, and wood and bagasse mixture ratio given energy and exergy efficiencies for ratios 75:25 is the best ratio of energy production. These results indicated that deodar wood is more stable because thermal stability of wood is greater than bagasse. Deodar is a suitable source for the combustion purposes of higher energy production.

3_D modeling using TLS and GPR techniques to characterize above and below-ground wood distribution in pyroclastic deposits along the Blanco River (Chilean Patagonia)

NASA Astrophysics Data System (ADS)

Valdebenito, Galo; Tonon, Alessia; Iroume, Andrés; Alvarado, David; Fuentes, Carlos; Picco, Lorenzo; Lenzi, Mario

2016-04-01

To date, the study of in-stream wood in rivers has been focused mainly on quantifying wood pieces deposited above the ground. However, in some particular river systems, the presence of buried dead wood can also represent an important component of wood recruitment and budgeting dynamics. This is the case of the Blanco River (Southern Chile) severely affected by the eruption of Chaitén Volcano occurred between 2008 and 2009. The high pyroclastic sediment deposition and transport affected the channel and the adjacent forest, burying wood logs and standing trees. The aim of this contribution is to assess the presence and distribution of wood in two study areas (483 m2 and 1989 m2, respectively) located along the lower streambank of the Blanco River, and covered by thick pyroclastic deposition up to 5 m. The study areas were surveyed using two different devices, a Terrestrial Laser Scanner (TLS) and a Ground Penetrating Radar (GPR). The first was used to scan the above surface achieving a high point cloud density (≈ 2000 points m-2) which allowed us to identify and measure the wood volume. The second, was used to characterize the internal morphology of the volcanic deposits and to detect the presence and spatial distribution of buried wood up to a depth of 4 m. Preliminary results have demonstrated differences in the numerousness and volume of above wood between the two study areas. In the first one, there were 43 wood elements, 33 standing trees and 10 logs, with a total volume of 2.96 m3 (109.47 m3 km-1), whereas the second one was characterized by the presence of just 7 standing trees and 11 wood pieces, for a total amount of 0.77 m3 (7.73 m3 km-1). The dimensions of the wood elements vary greatly according to the typology, standing trees show the higher median values in diameter and length (0.15 m and 2.91 m, respectively), whereas the wood logs were smaller (0.06 m and 1.12 m, respectively). The low dimensions of deposited wood can be probably connected to their origin, suggesting that these elements were generated by toppling and breaking of surrounding dead trees. Results obtained with the GPR confirm the ability of this instrument to localize the presence and distribution of buried wood. From the 3-D analysis it was possible to assess the spatial distribution and to estimate, as first approach, the volume of the buried wood which represents approximately 0.04% of the entire volcanic deposit. Further analysis will focus on additional GPR calibration with different wood sizes for a more accurate estimation of the volume. The knowledge of the overall wood amount stored in a fluvial system that can be remobilized over time, represent an essential factor to ensure better forest and river management actions.

Environmental controls of wood entrapment in upper Midwestern streams

USGS Publications Warehouse

Merten, Eric C.; Finlay, Jacques; Johnson, Lucinda; Newman, Raymond; Stefan, Heinz; Vondracek, Bruce C.

2011-01-01

Wood deposited in streams provides a wide variety of ecosystem functions, including enhancing habitat for key species in stream food webs, increasing geomorphic and hydraulic heterogeneity and retaining organic matter. Given the strong role that wood plays in streams, factors that influence wood inputs, retention and transport are critical to stream ecology. Wood entrapment, the process of wood coming to rest after being swept downstream at least 10 m, is poorly understood, yet important for predicting stream function and success of restoration efforts. Data on entrapment were collected for a wide range of natural wood pieces (n = 344), stream geomorphology and hydraulic conditions in nine streams along the north shore of Lake Superior in Minnesota. Locations of pieces were determined in summer 2007 and again following an overbank stormflow event in fall 2007. The ratio of piece length to effective stream width (length ratio) and the weight of the piece were important in a multiple logistic regression model that explained 25% of the variance in wood entrapment. Entrapment remains difficult to predict in natural streams, and often may simply occur wherever wood pieces are located when high water recedes. However, this study can inform stream modifications to discourage entrapment at road crossings or other infrastructure by applying the model formula to estimate the effective width required to pass particular wood pieces. Conversely, these results could also be used to determine conditions (e.g. pre-existing large, stable pieces) that encourage entrapment where wood is valued for ecological functions.

Generation rate and particle size distribution of wood dust by handheld sanding operation.

PubMed

Ojima, Jun

2016-11-29

The International Agency for Research on Cancer (IARC) and Japan Society for Occupational Health (JSOH) classified wood dust as a human carcinogen. Former studies have suggested that sanding with a portable sander is one of the processes that are liable to cause highest exposure to wood dust. However, the wood dust by sanding operation has not been investigated sufficiently. In this study, the generation rate and the particle size distribution of the wood dust produced by handheld sanding operation were observed by laboratory experiments. Beech and cypress were taken as typical hard and soft wood specimen respectively, and sanded with a portable sander. Three grades of sand paper (coarse, medium, fine) were attached to the sander in turn to be tested. The quantity of the wood dust produced by the sander was measured by weighing the specimen before and after the sanding and then the generation rate of the dust was calculated. Soft wood generated more dust than hard wood due to the difference in abrasion durability. A coarse sand paper produced more dust than a fine sand paper. The particles of less than 1 μm diameter were scarcely observed in the wood dust. When the specimens were sanded with a fine sand paper, the mass median aerodynamic diameters of beech dust and cypress dust were 9.0 μm and 9.8 μm, respectively. Respirable wood dust is able to be controlled by general ventilation with more than 0.7-4.2 m 3 /min ventilation rate.

Wood Litter Consumption by three Species of Nasutitermes Termites in an Area of the Atlantic Coastal Forest in Northeastern Brazil

PubMed Central

Vasconcellos, Alexandre; Moura, Flávia Maria da Silva

2010-01-01

Termites constitute a considerable fraction of the animal biomass in tropical forest, but little quantitative data are available that indicates their importance in the processes of wood decomposition. This study evaluated the participation of Nasutitermes corniger (Motschulsky) (Isoptera: Termitidae), N. ephratae (Holmgren), and N. macrocephalus (Silvestri) in the consumption of the wood litter in a remnant area of Atlantic Coastal Forest in northeastern Brazil. The populations of this species were quantified in nests and in decomposing tree trunks, while the rate of wood consumption was determined in the laboratory using wood test-blocks of Clitoria fairchildiana Howard (Fabales: Fabaceae), Cecropia sp. (Urticales: Cecropiaceae), and Protium heptaphyllum (Aublet) Marchand (Sapindales: Burseraceae). The abundance of the three species of termites varied from 40.8 to 462.2 individuals/m2. The average dry wood consumption for the three species was 9.4 mg/g of termites (fresh weight)/day, with N. macrocephalus demonstrating the greatest consumption (12.1 mg/g of termite (fresh weight)/day). Wood consumption by the three species of Nasutitermes was estimated to be 66.9 kg of dry wood /ha/year, corresponding to approximately 2.9% of the annual production of wood-litter in the study area. This consumption, together with that of the other 18 exclusively wood-feeders termite species known to occur in the area, indicates the important participation of termites in removing wood-litter within the Atlantic Coastal Forest domain. PMID:20673190

Habitat creation and biodiversity maintenance in mangrove forests: teredinid bivalves as ecosystem engineers

PubMed Central

Michie, Laura; Taylor, Ben W.

2014-01-01

Substantial amounts of dead wood in the intertidal zone of mature mangrove forests are tunnelled by teredinid bivalves. When the tunnels are exposed, animals are able to use tunnels as refuges. In this study, the effect of teredinid tunnelling upon mangrove forest faunal diversity was investigated. Mangrove forests exposed to long emersion times had fewer teredinid tunnels in wood and wood not containing teredinid tunnels had very few species and abundance of animals. However, with a greater cross-sectional percentage surface area of teredinid tunnels, the numbers of species and abundance of animals was significantly higher. Temperatures within teredinid-attacked wood were significantly cooler compared with air temperatures, and animal abundance was greater in wood with cooler temperatures. Animals inside the tunnels within the wood may avoid desiccation by escaping the higher temperatures. Animals co-existing in teredinid tunnelled wood ranged from animals found in terrestrial ecosystems including centipedes, crickets and spiders, and animals found in subtidal marine ecosystems such as fish, octopods and polychaetes. There was also evidence of breeding within teredinid-attacked wood, as many juvenile individuals were found, and they may also benefit from the cooler wood temperatures. Teredinid tunnelled wood is a key low-tide refuge for cryptic animals, which would otherwise be exposed to fishes and birds, and higher external temperatures. This study provides evidence that teredinids are ecosystem engineers and also provides an example of a mechanism whereby mangrove forests support intertidal biodiversity and nurseries through the wood-boring activity of teredinids. PMID:25276505

Characterization of carbonaceous aerosols emitted from outdoor wood boilers

EPA Science Inventory

This study examines the chemical properties of carbonaceous aerosols emitted from different outdoor wood-fired boiler (OWB) technologies including two cord-wood heaters, a pellet heater, and a multistage gasifier/combustor. The effect of fuel type [red oak wood (Quercus rubra), w...

Wood preservation

Treesearch

Rebecca E. Ibach

2003-01-01

When wood is exposed to various environmental conditions, many degradation reactions (biological, ultraviolet, mechanical, moisture, and chemical) can occur. To protect wood from biological degradation, chemical preservatives are applied by nonpressure or pressure treatment. Penetration and retention of a chemical depend upon the wood species and the amount of...

78 FR 30329 - Multilayered Wood Flooring from China

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-22

...)] Multilayered Wood Flooring from China AGENCY: United States International Trade Commission. ACTION: Notice of...-1179 (Final) concerning multilayered wood flooring (``MLWF'') from China. For further information... Hardwood Floors, Inc.; BR Custom Surface; Real Wood Floors, LLC; Galleher Corp.; and DPR International, LLC...

75 FR 66126 - Multilayered Wood Flooring From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-27

...)] Multilayered Wood Flooring From China AGENCY: United States International Trade Commission. ACTION: Institution... the United States is materially retarded, by reason of imports from China of multilayered wood... multilayered wood flooring. The following companies are members of the CAHP: Anderson Hardwood Floors, LLC...

Image analysis of multiple moving wood pieces in real time

NASA Astrophysics Data System (ADS)

Wang, Weixing

2006-02-01

This paper presents algorithms for image processing and image analysis of wood piece materials. The algorithms were designed for auto-detection of wood piece materials on a moving conveyor belt or a truck. When wood objects on moving, the hard task is to trace the contours of the objects in n optimal way. To make the algorithms work efficiently in the plant, a flexible online system was designed and developed, which mainly consists of image acquisition, image processing, object delineation and analysis. A number of newly-developed algorithms can delineate wood objects with high accuracy and high speed, and in the wood piece analysis part, each wood piece can be characterized by a number of visual parameters which can also be used for constructing experimental models directly in the system.

The use of wood for wind turbine blade construction

NASA Technical Reports Server (NTRS)

Gougeon, M.; Zuteck, M.

1979-01-01

The interrelationships between moisture and wood, conditions for dry rot spore activity, the protection of wood fibers from moisture, wood resin composites, wood laminating, quality control, and the mechanical properties of wood are discussed. The laminated veneer and the bonded sawn stock fabrication techniques, used in the construction of a turbine blade with a monocoque 'D' section forming the leading edge and a built up trailing edge section, are described. A 20 foot root end sample complete with 24 bonded-in studs was successfully subjected to large onetime loads in both the flatwise and edgewise directions, and to fatigue tests. Results indicate that wood is both a viable and advantageous material for use in wind turbine blades. The basic material is reasonably priced, domestically available, ecologically sound, and easily fabricated with low energy consumption.

Abundance of large old trees in wood-pastures of Transylvania (Romania).

PubMed

Hartel, Tibor; Hanspach, Jan; Moga, Cosmin I; Holban, Lucian; Szapanyos, Árpád; Tamás, Réka; Hováth, Csaba; Réti, Kinga-Olga

2018-02-01

Wood-pastures are special types of agroforestry systems that integrate trees with livestock grazing. Wood pastures can be hotspots for large old tree abundance and have exceptional natural values; but they are declining all over Europe. While presence of large old trees in wood-pastures can provide arguments for their maintenance, actual data on their distribution and abundance are sparse. Our study is the first to survey large old trees in Eastern Europe over such a large area. We surveyed 97 wood-pastures in Transylvania (Romania) in order to (i) provide a descriptive overview of the large old tree abundance; and (ii) to explore the environmental determinants of the abundance and persistence of large old trees in wood-pastures. We identified 2520 large old trees belonging to 16 taxonomic groups. Oak was present in 66% of the wood-pastures, followed by beech (33%), hornbeam (24%) and pear (22%). For each of these four species we constructed a generalized linear model with quasi-Poisson error distribution to explain individual tree abundance. Oak trees were most abundant in large wood-pastures and in wood-pastures from the Saxon cultural region of Transylvania. Beech abundance related positively to elevation and to proximity of human settlements. Abundance of hornbeam was highest in large wood-pastures, in wood-pastures from the Saxon cultural region, and in places with high cover of adjacent forest and a low human population density. Large old pear trees were most abundant in large wood-pastures that were close to paved roads. The maintenance of large old trees in production landscapes is a challenge for science, policy and local people, but it also can serve as an impetus for integrating economic, ecological and social goals within a landscape. Copyright © 2017 Elsevier B.V. All rights reserved.

Respiratory symptoms and lung function in relation to wood dust and monoterpene exposure in the wood pellet industry.

PubMed

Löfstedt, Håkan; Hagström, Katja; Bryngelsson, Ing-Liss; Holmström, Mats; Rask-Andersen, Anna

2017-06-01

Wood pellets are used as a source of renewable energy for heating purposes. Common exposures are wood dust and monoterpenes, which are known to be hazardous for the airways. The purpose of this study was to study the effect of occupational exposure on respiratory health in wood pellet workers. Thirty-nine men working with wood pellet production at six plants were investigated with a questionnaire, medical examination, allergy screening, spirometry, and nasal peak expiratory flow (nasal PEF). Exposure to wood dust and monoterpenes was measured. The wood pellet workers reported a higher frequency of nasal symptoms, dry cough, and asthma medication compared to controls from the general population. There were no differences in nasal PEF between work and leisure time. A lower lung function than expected (vital capacity [VC], 95%; forced vital capacity in 1 second [FEV 1 ], 96% of predicted) was noted, but no changes were noted during shifts. There was no correlation between lung function and years working in pellet production. Personal measurements of wood dust at work showed high concentrations (0.16-19 mg/m 3 ), and exposure peaks when performing certain work tasks. Levels of monoterpenes were low (0.64-28 mg/m 3 ). There was no association between exposure and acute lung function effects. In this study of wood pellet workers, high levels of wood dust were observed, and that may have influenced the airways negatively as the study group reported upper airway symptoms and dry cough more frequently than expected. The wood pellet workers had both a lower VC and FEV 1 than expected. No cross-shift changes were found.

Wood-related occupations, wood dust exposure, and sinonasal cancer.

PubMed

Hayes, R B; Gerin, M; Raatgever, J W; de Bruyn, A

1986-10-01

A case-control study was conducted to examine the relations between type of woodworking and the extent of wood dust exposure to the risks for specific histologic types of sinonasal cancer. In cooperation with the major treatment centers in the Netherlands, 116 male patients newly diagnosed between 1978 and 1981 with primary malignancies of epithelial origin of this site were identified for study. Living controls were selected from the municipal registries, and deceased controls were selected from the national death registry. Interviews were completed for 91 (78%) cases and 195 (75%) controls. Job histories were coded by industry and occupation. An index of exposure was developed to classify the extent of occupational exposure to wood dust. When necessary, adjustment was made for age and usual cigarette use. The risk for nasal adenocarcinoma was elevated by industry for the wood and paper industry (odds ratio (OR) = 11.9) and by occupation for those employed in furniture and cabinet making (OR = 139.8), in factory joinery and carpentry work (OR = 16.3), and in association with high-level wood dust exposure (OR = 26.3). Other types of nasal cancer were not found to be associated with wood-related industries or occupations. A moderate excess in risk for squamous cell cancer (OR = 2.5) was associated with low-level wood dust exposure; however, no dose-response relation was evident. The association between wood dust and adenocarcinoma was strongest for those employed in wood dust-related occupations between 1930 and 1941. The risk of adenocarcinoma did not appear to decrease for at least 15 years after termination of exposure to wood dust. No cases of nasal adenocarcinoma were observed in men whose first exposure to wood dust occurred after 1941.

Evaluation of three bait materials and their food transfer efficiency in Formosan subterranean termites (Isoptera: Rhinotermitidae).

PubMed

Wang, Cai; Henderson, Gregg

2012-10-01

The consumption and food transfer efficiency of two commercially used termite bait materials, southern yellow pine wood and cardboard, and one potential bait material, maize (Zea mays L.) cob, were evaluated for use against the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in the laboratory. In the no-choice test, the consumption of wood and cob was similar and significantly more than cardboard. Tunneling under the food sources was similar. In the two-choice test, the consumption was cob > wood, wood > cardboard, cob = cardboard, and tunneling under these choices was cob = wood, wood = cardboard, cob > cardboard. In the three-choice test, no significant difference was detected in consumption, but tunnels made under the cob were significantly more than wood and cardboard. Nile blue A was used to study food transfer of bait material among termite cohorts. Dyed cardboard, cob, or wood (0.1% Nile blue A) was provided to termites as food. Termites feeding on wood turned blue in significantly greater number at 6 h compared with cardboard and cob, but there was no significant difference after 12 h. Blue termites feeding on different bait materials were then collected and combined with undyed termites. When undyed (white) termites were placed with blue termites and food (wood block), termites turned blue in the same percentage regardless of original bait material fed on. However, when no food was provided (starvation group), the rate of white termites turning blue was dramatic; in dyed wood treatment, significantly more termites turned blue than that of cardboard, although neither were significantly different from cob. Our study is the first to show that, cob, an otherwise waste product of the food and biofuel industry, is as efficient as wood and cardboard as a termite bait matrix.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard F. Daniels; Alexander Clark III

The forest industry will increasingly rely on fast-growing intensively managed southern pine plantations to furnish wood and fiber. Intensive silvicultural practices, including competition control, stand density control, fertilization, and genetic improvement are yielding tremendous gains in the quantity of wood production from commercial forest land. How these technologies affect wood properties was heretofore unknown, although there is concern about the suitability of fast-grown wood for traditional forest products. A four year study was undertaken to examine the effects of these intensive practices on the properties of loblolly and slash pine wood by applying a common sampling method over 10 existingmore » field experiments. Early weed control gets young pines off to a rapid start, often with dramatically increased growth rates. This response is all in juvenile wood however, which is low in density and strength. Similar results are found with early Nitrogen fertilization at the time of planting. These treatments increase the proportion of juvenile wood in the tree. Later, mid-rotation fertilization with Nitrogen and Phosphorus can have long term (4-8 year) growth gains. Slight reductions in wood density are short-lived (1-2 years) and occur while the tree is producing dense, stiff mature wood. Impacts of mid-rotation fertilization on wood properties for manufacturing are estimated to be minimal. Genetic differences are evident in wood density and other properties. Single family plantings showed somewhat more uniform properties than bulk improved or unimproved seedlots. Selection of genetic sources with optimal wood properties may counter some of the negative impacts of intensive weed control and fertilization. This work will allow forest managers to better predict the effects of their practices on the quality of their final product.« less

Respiratory symptoms and lung function in relation to wood dust and monoterpene exposure in the wood pellet industry

PubMed Central

Löfstedt, Håkan; Hagström, Katja; Bryngelsson, Ing-Liss; Holmström, Mats; Rask-Andersen, Anna

2017-01-01

Introduction Wood pellets are used as a source of renewable energy for heating purposes. Common exposures are wood dust and monoterpenes, which are known to be hazardous for the airways. The purpose of this study was to study the effect of occupational exposure on respiratory health in wood pellet workers. Materials and methods Thirty-nine men working with wood pellet production at six plants were investigated with a questionnaire, medical examination, allergy screening, spirometry, and nasal peak expiratory flow (nasal PEF). Exposure to wood dust and monoterpenes was measured. Results The wood pellet workers reported a higher frequency of nasal symptoms, dry cough, and asthma medication compared to controls from the general population. There were no differences in nasal PEF between work and leisure time. A lower lung function than expected (vital capacity [VC], 95%; forced vital capacity in 1 second [FEV1], 96% of predicted) was noted, but no changes were noted during shifts. There was no correlation between lung function and years working in pellet production. Personal measurements of wood dust at work showed high concentrations (0.16–19 mg/m3), and exposure peaks when performing certain work tasks. Levels of monoterpenes were low (0.64–28 mg/m3). There was no association between exposure and acute lung function effects. Conclusions In this study of wood pellet workers, high levels of wood dust were observed, and that may have influenced the airways negatively as the study group reported upper airway symptoms and dry cough more frequently than expected. The wood pellet workers had both a lower VC and FEV1 than expected. No cross-shift changes were found. PMID:28276782

Impacts of age-dependent tree sensitivity and dating approaches on dendrogeomorphic time series of landslides

NASA Astrophysics Data System (ADS)

Šilhán, Karel; Stoffel, Markus

2015-05-01

Different approaches and thresholds have been utilized in the past to date landslides with growth ring series of disturbed trees. Past work was mostly based on conifer species because of their well-defined ring boundaries and the easy identification of compression wood after stem tilting. More recently, work has been expanded to include broad-leaved trees, which are thought to produce less and less evident reactions after landsliding. This contribution reviews recent progress made in dendrogeomorphic landslide analysis and introduces a new approach in which landslides are dated via ring eccentricity formed after tilting. We compare results of this new and the more conventional approaches. In addition, the paper also addresses tree sensitivity to landslide disturbance as a function of tree age and trunk diameter using 119 common beech (Fagus sylvatica L.) and 39 Crimean pine (Pinus nigra ssp. pallasiana) trees growing on two landslide bodies. The landslide events reconstructed with the classical approach (reaction wood) also appear as events in the eccentricity analysis, but the inclusion of eccentricity clearly allowed for more (162%) landslides to be detected in the tree-ring series. With respect to tree sensitivity, conifers and broad-leaved trees show the strongest reactions to landslides at ages comprised between 40 and 60 years, with a second phase of increased sensitivity in P. nigra at ages of ca. 120-130 years. These phases of highest sensitivities correspond with trunk diameters at breast height of 6-8 and 18-22 cm, respectively (P. nigra). This study thus calls for the inclusion of eccentricity analyses in future landslide reconstructions as well as for the selection of trees belonging to different age and diameter classes to allow for a well-balanced and more complete reconstruction of past events.

Manufacture of reconstruction-bricks in Mexico

NASA Astrophysics Data System (ADS)

Rojas-Valencia, Ma. Neftalí; Penagos, Armando Aguilar; Rojas, Denise Y. Fernández; López, Alberto López; Gálves, David Morillón

2017-12-01

In Mexico, around 33.600 tons of construction wastes are generated every day, Mexico City contributing for around tons/day, with fewer than 1.000 tons/day being sent to be recycled. For that reason the purpose of this study was to manufacture sustainable bricks, based on three types of wastes generated in the building industry: wood cutting residues, wastes from the excavation process (From Coapa and Cuautlancingo, Puebla, Mexico) and recycled aggregates. Water was added as kneading material, and Opuntia ficus-indica (mucilage) was supplemented as natural additive to improve the workability of the mixtures. Conventional firing process was substituted by drying in a solar drying chamber. Nine mixtures were prepared using 62% excavation wastes, 4% wood cutting residues and 11%, 17% and 34% recycled aggregates. These mixtures were classified in two groups depending on their granulometry: the first one denominated cementitious recycled aggregates only having granulometry from 25.4 mm, 9.52 mm to 6.35 mm to fines and the second group denominated all in one recycled aggregates having granulometry of 6.35 mm to fines. The quality of the sustainable bricks was evaluated according to compressive strength and water absorption parameters. The results of nine mixtures showed that the reconstruction-bricks manufactured with the mixture seven consisting of 9.52 mm and 6.35 mm construction residues (all in one) fines presented the highest strength values, lowest maximum initial absorption (4 g/min) compared to the norm NMX-C-037-ONNCCE-2013 which establishes that the maximum limit for walls exposed to the outside is 5 g/min. Using a solar desiccator made from construction residues, the bricks were dried in 11 days, the maximum temperature was 76 °C and the maximum solar radiation captured was 733.4 W/m2.