Wood Species (wood + species)

Distribution by Scientific Domains

Selected Abstracts

Time to ignition, heat release rate and fire endurance time of wood in cone calorimeter test

Toshiro HaradaArticle first published online: 15 MAR 200
The combustibility of wood specimens was tested by cone calorimeter. A total of nine wood species (four softwood and five hardwood) were used. The thicknesses of the specimens were 10, 20 and 40 mm. The heated surfaces were radial, tangential, and cross-sections of wood. The irradiance levels were 20, 25, 30, 40 and 50 kWm,2. The effects of wood species, density, specimen thickness, heated surface (radial, tangential or cross-section), and irradiance level on time to ignition, mass loss rate, heat release rate and fire endurance time were studied. Simple formulae were proposed to forecast those indices and their validity was examined. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Strategies to reduce the brightness reversion of industrial ECF bleached Eucalyptus globulus kraft pulp

Isabel M. C. L. Sêco
Abstract BACKGROUND: Brightness stability is a key property of bleached chemical pulps and is primarily determined by wood species and bleaching process conditions. Eucalyptus globulus is becoming a very important raw material for hardwood pulp production. In spite of this importance, there is a relative lack of systematic studies in the literature dealing with the subject. This research aims to study the effect of some of the foremost bleaching parameters of a DEDD bleaching sequence as well as the effect of a final P stage (DEDP instead of DEDD) in the brightness stability of bleached E. globulus kraft pulps. RESULTS: The increase of the D0 stage temperature from 55 °C to 90 °C caused an increase in brightness stability. Increasing the ClO2 charges from 2.8% to 3.2% also improved significantly the brightness stability. A high H2SO4 charge in the D0 stage (10 kg tonne,1 pulp) diminished the brightness stability. The combination of H2O2 addition to the E stage and ClO2 reduction in the two final D stages does not affect brightness reversion. Raising the D2 stage temperature from 65 °C to 82 °C decreased the brightness reversion, while an increase was obtained when the temperature rose above 82 °C. Substitution of the last ClO2 stage in the DEDD sequence by a H2O2 stage (DEDP) significantly reduced the brightness reversion. CONCLUSION: For an existing pulp mill in which the implementation of new technologies to improve brightness reversion is considered, the results obtained showed that brightness stability can be improved without any significant capital investment. Copyright © 2007 Society of Chemical Industry [source]

Fusion characteristics of rigid PVC/wood-flour composites by torque rheometry

Laurent M. Matuana
This study was aimed at examining the effects of wood flour contents, wood species (softwood vs. hardwood), and particle size on the fusion characteristics (fusion time, fusion temperature, fusion torque, and fusion energy) of rigid PVC/wood-flour composites in a torque rheometer. Neat rigid PVC exhibited one fusion peak, whereas the addition of wood flour into the PVC matrix led to two fusion peaks. Increased wood flour content caused a significant increase in the time, temperature, and energy at which fusion between the primary particles started, thereby leading to increased fusion torque, irrespective of the wood flour species. These results implied that rigid PVC filled with wood flour must be processed at higher temperatures than neat resin. Although fusion characteristics of the composites were influenced by the wood species, a clear trend between softwood and hardwood species could not be established. However, finer particles fused more quickly and needed less energy than coarse ones. J. VINYL ADDIT. TECHNOL., 13:7,13, 2007. © 2007 Society of Plastics Engineers. [source]

Physico-Mechanical Properties and the TVOC Emission Factor of Gypsum Particleboards Manufactured with Pinus Massoniana and Eucalyptus Sp.

Sumin Kim
Abstract The effect of wood species on the TVOC emission factor and the physico-mechanical properties of GPBs is investigated. Of the two wood species, the water absorption was higher for the GPBs made using Eucalyptus sp. than for those using Pinus massoniana. The Eucalyptus sp. GPBs pressed at room temperature, 40 and 60,°C all demonstrated higher moisture absorption than commercial GPBs. The TVOC emission factor decreased with increasing press temperature, especially for Eucalyptus sp. but remained under ,excellent' grade as defined by the KACA. From these results, GPB with higher content of wood particles should be considered for the replacement of wood-based panels such as particleboard and medium density fiberboard (MDF). [source]


ARCHAEOMETRY, Issue 4 2010
A series of 112 waterlogged archaeological wood samples of different provenances, wood species, burial times and states of preservation were analysed with the aim of assessing the validity (in terms of limits and reliability) of procedures conventionally used in the pulp and paper industry, to evaluate the state of preservation of decayed wood. In particular, the extent of any damage wrought on decayed wood tissue by the repetitive cycles that characterize these procedures was evaluated as a function of the degradation of the samples. The results indicated that standard methodologies give reliable measurements regardless of the extent of wood decay. However, it is essential to compare these data with those of non-decayed wood that has been measured using the same procedures to take account of the errors that are inherent in these methodologies and that affect measurements. [source]

Wasserdampfsorptionsverhalten ausgewählter heimischer und überseeischer Holzarten

BAUPHYSIK, Issue 2 2009
Rudolf Popper Dipl.-Ing.
Feuchte; Versuche Abstract An 21 heimischen und 11 überseeischen Holzarten wurde die Gleichgewichtsfeuchte bei 20 °C und 35, 50, 65, 80 und 95 % relativer Luftfeuchtigkeit experimentell in der Adsorptionsphase bestimmt. Aufbauend auf den experimentell bestimmten Mittelwerten wurden mit dem Hailwood-Horrobin-Modell (HH-Modell) ausgewählte Parameter wie Fasersättigungsfeuchte, mono- und polymolekulare Sorption, spezifische Oberfläche des Sorbenten, hypothetisches Molekulargewicht des Sorbenten sowie Unzugänglichkeit des Sorbenten zum Sorbat berechnet. Zusätzlich wurden Tabellen für die Gleichgewichtsfeuchte bei 20 °C und in 2-%-Schritten abgestufter relativer Luftfeuchtigkeit berechnet. Die mittels des HH-Modells berechnete Fasersättigungsfeuchte liegt für alle geprüften Holzarten im Bereich zwischen 22 bis 36 %, im Mittel bei ca. 30 %. Es treten erhebliche Abweichungen zwischen den einzelnen Holzarten in der Fasersättigungsfeuchte auf. Die Tendenzen für die Kenngrößen der Sorptionsanalyse wurden aufgezeigt. Water vapour sorption behaviour of selected domestic and overseas wood species. At 21 domestic and 11 overseas wood species the equilibrium moisture content at 20 °C and 35, 50, 65, 80 and 95% relative humidity was experimentally determined in the adsorption phase. The experimentally determined average values were computed with help of the Hailwood Horrobin model to get selected parameters such as fiber saturation point, mono- and polymolecular sorption, specific surface, hypothetical molecular weight as well as inaccessibility of the sorbent to the sorbate. Tables for the equilibrium moisture contents at 20 °C computed in 2% steps of relative humidity are presented. The fiber saturation point computed with the Hailwood-Horrobin model lies for all examined wood in the range from 22% to 36%, on the average with approx. 30%. There are substantial deviations in the fiber saturation point between the individual wood species. The tendencies for the characteristics of the sorption analysis were pointed out. [source]