Wood Types (wood + type)

Distribution by Scientific Domains

Selected Abstracts

Impact of impregnation chemical on surface glossiness of synthetic, acrylic, polyurethane, and water-based varnishes

Hakan Keskin
Abstract This study was performed to determine the effects of impregnation chemical on surface glossiness of some varnishes. For this purpose, the test samples prepared from Oriental beech, European oak, Scotch pine, Oriental spruce, and Uludag fir woods according to ASTM D 358 were impregnated with Imersol-Aqua according to ASTM D 1413 and producer's definition by short-term (S), medium-term (M), and long-term (L) of dipping methods and coated by synthetic (Sv), acrylic (Ac), water-based (Wb), and polyurethane (Pu) varnishes according to ASTM D 3023. After the varnishing process, the surface glossiness parallel to fibers was determined according to TS 4318. Consequently, among the nonimpregnated wood samples, surface glossiness parallel to fibers was found to be the highest in Oriental spruce and the lowest in European oak. As for the period of dipping, the highest surface glossiness was obtained in medium-term dipping and the lowest in long-term dipping. As for the varnish types, the surface glossiness was found to be the highest in polyurathane varnish and the lowest in water-based varnish. Considering the interaction of wood type, period of impregnation, and type of varnish, surface glossiness was the highest in Uludag fir, long-term dipping, and polyurathane varnish (103.9 gloss) and the lowest in Oriental beech, long-term dipping, and water-based varnish (67.78 gloss). In consequence, in the massive constructions and furniture elements the surface glossiness parallel to fibers after the impregnation with Imersol-Aqua is of great concern, long-term impregnation of Uludag fir materials could be recommended. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Wood-Derived Porous SiC Ceramics by Sol Infiltration and Carbothermal Reduction

Andreas Herzog
A new method for transforming wood structures into ceramic by carbothermal reduction of silica and carbonized wood has been developed. Application of this technique allows the preservation of wood microstructures in the ceramic state and the conversion of wood components without constraints in component size. The chosen infiltration technique of silica sol incorporation into carbonized wood structures is examined in terms of sol and wood type, carbonization conditions of the wood, and thickness of the infiltrated carbon body. Ceramization conditions were optimized, and the reaction mechanism is discussed. [source]

Corrosion behaviour of tool steels in tannic acids

H. Winkelmann
Abstract It is well known that cutting knifes in the wood industry often suffer from corrosion. Investigations showed that the corrosiveness of different wood types is responsible for a major part of the damage, and that different woods have a different corrosive impact. It is revealed that tannin, a water-soluble acid, which can be found in all woods in different concentrations, is the most aggressive acid contained in the wood, and so it is responsible for the main part of the corrosive attack. In view of the above, the ability of different cold-work steels to resist corrosion caused by tannic acid has been investigated. Often corrosion is measured by the mass loss of the sample divided by the surface of the sample under certain conditions during a fixed period of time. One problem with this method is that there is also a weight gain caused by oxidation or by other side reactions at the samples surface. So in some cases the weight of the sample even increases during the testing time, which makes the quantification of the corrosion impossible with this method. Due to the reasons already mentioned, another method was used to quantify the test results. This method is based on inductive coupled plasma,optical emission spectral analyses (ICP-OES), where the released Fe is quantified. The results of the corrosion resistant tests get correlated to the microstructure and the elemental composition of the analysed cold-work steels. The present investigations improve the understanding of important material parameters to enhance the corrosion resistance against tannin. It is revealed that the higher the primary carbide concentration is the more Cr or other passivating elements are necessary in the matrix to show a good protection against corrosion by tannin. Three materials with different elemental compositions have been investigated, and for one of those materials the influence of different heat treatments was also analysed. The investigations could show that annealing parameters and freeze-cycle processing (FCP) have less impact on the corrosion resistance to tannin than elemental composition and austenitising temperature. [source]

Fossil Woods From Williams Point Beds, Livingston Island, Antarctica: A Late Cretaceous Southern High Latitude Flora

Imogen Poole
The wood flora from Williams Point, Livingston Island, contains 12 wood types of gymnosperm and angiosperm origin. Recent collections of material have increased the biodiversity of a postulated species-rich vegetation. The gymnosperm wood can be readily assigned to four form-genera: Araucarioxylon Kraus, Araucariopitys Jeffrey, Podocarpoxylon Gothan and Sahnioxylon Bose and Sah. This indicates a diversity of coniferous araucarian and podocarp trees alongside woods of uncertain affinity (Sahnioxylon; Bennettitales). Two angiosperm morphotypes are assigned to the organ genera Hedycaryoxylon Su¨ss (Monimiaceae) and Weinmannioxylon Petriella (Cunoniaceae). The remaining four taxa of angiosperm wood cannot be confidently placed in extant families as they exhibit features that suggest relationships with the Magnoliidae, Hamamelidae and Rosidae. This paper presents the first comprehensive taxonomic revision of the wood flora from Livingston Island and discusses the palaeoecology that prevailed at a latitude of about 60 degrees south during the Late Cretaceous. Newly described taxa are Araucarioxylon chapmanae sp. nov., Araucariopitys antarcticus sp. nov., Podocarpoxylon chapmanae sp. nov., P. verticalis sp. nov., P. communis sp. nov., Weinmannioxylon ackamoides sp. nov., Antarctoxylon livingstonensis gen. et sp. nov., A. multiseriatum gen. et sp. nov., A. heteroporosum gen. et sp. nov. and A. uniperforatum gen et sp. nov. [source]

The role of wood anatomy in phylogeny reconstruction of Ericales

CLADISTICS, Issue 3 2007
Frederic Lens
The systematic significance of wood anatomical characters within Ericales is evaluated using separate and combined parsimony analyses including 23 wood characters and 3945 informative molecular characters. Analyses of wood features alone result in poorly resolved and conflicting topologies. However, when pedomorphic character states are coded as inapplicable, the combined bootstrap topology results in an increase of resolution and support at most deeper nodes compared with the molecular analyses. This suggests that phylogenetic information from the limited number of morphological characters is not completely swamped by an overwhelming amount of molecular data. Based on the morphology of vessels and fibers, and the distribution of axial parenchyma, two major wood types can be distinguished within Ericales: (i) a "primitive" type, nearly identical to the wood structure in the more basal outgroup Cornales, which is likely to have persisted in one major clade, and (ii) a "derived" type that must have evolved in at least two separate evolutionary lines. The occurrence of the first type is strongly correlated with shrubs to small trees growing in cold temperate or tropical montane regions, while the second type is common in tall trees of tropical lowlands. This favors the inclusion of ecologically adaptive features in phylogeny reconstruction. © The Willi Hennig Society 2006. [source]