On The Permeability of Main Wood Species in China

Holzforschung ◽  
1999 ◽  
Vol 53 (4) ◽  
pp. 350-354 ◽  
Author(s):  
Fucheng Bao ◽  
Jianxiong Lu ◽  
Stavros Avramidis
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
Air Permeability ◽  
Low Permeability ◽  
Diffuse Porous

Summary This research dealt with the longitudinal air permeability of 40 important Chinese woods. The air permeabilities measured at about 10% moisture content for softwoods ranged between 0.00759 and 1.87130 darcy, while for hardwoods ranged between 0.00182 and 13.49867 darcy. The sapwood permeability of both softwoods and hardwoods was generally much higher than that of heartwood with 3 to 144 and 1 to 1302 times, respectively. The permeability values of wood were not affected by density between and within species. In all species studied, the permeability of heartwood of all softwoods, about 70% ring-porous and about 30% diffuse-porous or semi-diffuse porous hardwoods were below 0.1 darcy. The number of low permeability softwoods was higher than that of hardwoods. The number of low permeability ring-porous hardwoods was higher than that of diffuse-porous or semi-diffuse porous hardwoods. Finally, all the studied species were classified into five categories by their longitudinal permeabilities.

Influence of Moisture Content in some Mechanical Properties of Two Brazilian Tropical Wood Species

2014 ◽  
Vol 1025-1026 ◽  
pp. 42-45 ◽  
Author(s):  
Luiz A. Melgaço N. Branco ◽  
Eduardo Chahud ◽  
André Luis Christoforo ◽  
Francisco Antonio Rocco Lahr ◽  
Rosane A.G. Battistelle ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Moisture Content ◽  
Analysis Of Variance ◽  
Wood Species ◽  
Modulus Of Elasticity ◽  
Modulus Of Rupture ◽  
Tropical Wood ◽  
Fiber Saturation ◽  
Brazilian Standard

This study aimed, with the aid of analysis of variance (ANOVA), to investigate and quantify the influence of moisture ranging between 12% and over 30% (fiber saturation) on the mechanical properties: strength and modulus of elasticity in compression and in tension parallel to grain; modulus of rupture and modulus of elasticity in static bending; shear strength parallel to grain considering wood species Ipê (Tabebuia sp) and Angelim Araroba (Vataireopsis araroba). Tests were performed according to the assumptions and calculating methods Brazilian standard ABNT NBR 7190, Anexx B, totalizing 400 tests. Results of ANOVA revealed a significant reduction (16% on average) for mechanical properties wood due to the increase in moisture content from 12% to over 30% (fiber saturation). The same behavior also occurred when assembly containing the two species was considered.

scholarly journals Texture analysis of stereograms of diffuse-porous hardwood: identification of wood species used in Tripitaka Koreana

2017 ◽  
Vol 63 (4) ◽  
pp. 322-330 ◽  
Author(s):  
Kayoko Kobayashi ◽  
Sung-Wook Hwang ◽  
Won-Hee Lee ◽  
Junji Sugiyama
Keyword(s):  
Texture Analysis ◽  
Wood Species ◽  
Tripitaka Koreana ◽  
Diffuse Porous

scholarly journals Comparison of the Decay Behavior of Two White-Rot Fungi in Relation to Wood Type and Exposure Conditions

2020 ◽  
Vol 8 (12) ◽  
pp. 1931
Author(s):  
Ehsan Bari ◽  
Geoffrey Daniel ◽  
Nural Yilgor ◽  
Jong Sik Kim ◽  
Mohammad Ali Tajick-Ghanbary ◽  
...  
Keyword(s):  
Cell Wall ◽  
Moisture Content ◽  
Wood Species ◽  
White Rot Fungi ◽  
White Rot ◽  
High Mass ◽  
Type I ◽  
Oak Wood ◽  
Mass Losses ◽  
Decay Behavior

Fungal wood decay strategies are influenced by several factors, such as wood species, moisture content, and temperature. This study aims to evaluate wood degradation characteristics of spruce, beech, and oak after exposure to the white-rot fungi Pleurotusostreatus and Trametesversicolor. Both fungi caused high mass losses in beech wood, while spruce and oak wood were more resistant to decay. The moisture content values of the decayed wood correlated with the mass losses for all three wood species and incubation periods. Combined microscopic and chemical studies indicated that the two fungi differed in their decay behavior. While T. versicolor produced a decay pattern (cell wall erosion) typical of white-rot fungi in all wood species, P. ostreatus caused cell wall erosion in spruce and beech and soft-rot type I (cavity formation) decay in oak wood. These observations suggest that P. ostreatus may have the capacity to produce a wider range of enzymes/radicals triggered by the chemical composition of wood cell walls and/or local compositional variability within the cell wall.

scholarly journals Effect of Extractives on the Equilibrium Moisture Content and Shrinkage of Selected Tropical Wood Species

BioResources ◽  
2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Agnieszka Jankowska ◽  
Michał Drożdżek ◽  
Paweł Sarnowski ◽  
Jakub Horodeński
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Wood Species ◽  
Tropical Wood

scholarly journals Studies into Fungal Decay of Wood In Ground Contact—Part 1: The Influence of Water-Holding Capacity, Moisture Content, and Temperature of Soil Substrates on Fungal Decay of Selected Timbers

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1284
Author(s):  
Brendan Nicholas Marais ◽  
Christian Brischke ◽  
Holger Militz ◽  
Johann Hinrich Peters ◽  
Lena Reinhardt
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
General Trend ◽  
Wood Decay ◽  
European Beech ◽  
Water Holding Capacity ◽  
Inoculum Potential ◽  
Ground Contact ◽  
Fungal Decay ◽  
Water Holding

This article presents the results from two separate studies investigating the decay of wood in ground contact using adapted versions of laboratory-based terrestrial microcosm (TMC) tests according to CEN/TS 15083-2:2005. The first study (A) sought to isolate the effect of soil water-holding capacity (WHCsoil [%]) and soil moisture content (MCsoil [%WHCsoil]) on the decay of five commercially important wood species; European beech (Fagus sylvatica), English oak heartwood (Quercus robur), Norway spruce (Picea abies), Douglas-fir heartwood (Pseudotsuga menziesii), and Scots pine sapwood (Pinus sylvestris), while keeping soil temperature (Tsoil) constant. Combinations of soil mixtures with WHCsoil of 30%, 60%, and 90%, and MCsoil of 30%, 70%, and 95%WHCsoil were utilized. A general trend showed higher wood decay, measured in oven-dry mass loss (MLwood [%]), for specimens of all species incubated in soils with WHCsoil of 60% and 90% compared to 30%. Furthermore, drier soils (MCsoil of 30 and 70%WHCsoil) showed higher MLwood compared to wetter soils (95%WHCsoil). The second study (B) built on the first’s findings, and sought to isolate the effect of Tsoil and MCsoil on the decay of European beech wood, while keeping WHCsoil constant. The study used constant incubation temperature intervals (Tsoil), 5–40 °C, and alternating intervals of 10/20, 10/30, and 20/30 °C. A general trend showed drier MCsoil (60%WHCsoil), and Tsoil of 20–40 °C, delivered high wood decay (MLwood > 20%). Higher MCsoil (90%WHCsoil) and Tsoil of 5–10 °C, delivered low wood decay (MLwood < 5%). Alternating Tsoil generally delivered less MLwood compared to their mean constant Tsoil counterparts (15, 20, 25 °C). The results suggest that differences in wood species and inoculum potential (WHCsoil) between sites, as well as changes in MCsoil and Tsoil attributed to daily and seasonal weather patterns can influence in-ground wood decay rate.

scholarly journals New Laccase-Mediated System Utilized for Bio-Discoloration of Indigo-Dyed Denim Fabrics

2021 ◽  
Author(s):  
Mojtaba Sarafpour ◽  
Farzaneh Alihosseini ◽  
Maryam Bayat
Keyword(s):  
Moisture Content ◽  
Abrasion Resistance ◽  
Air Permeability ◽  
Surface Reflectance ◽  
Color Coordinates ◽  
Cellulase Enzyme ◽  
Sodium Hydrosulfite ◽  
Combined Use ◽  
Denim Fabric ◽  
Laccase Enzyme

Abstract In this study, indigo-dyed denim fabric was decolorized by washing and printing with separate and simultaneous applications of laccase enzyme, sodium hydrosulfite, and cellulase enzyme. In this regard, the surface reflectance and color coordinates of the discolored fabrics were analyzed, and SEM photographs of the treated fabrics were prepared to analyze their surfaces. Finally, the effects of the discoloration process and materials on various parameters of the treated samples were investigated, including moisture content, creaserecovery angle, air permeability, and abrasion resistance. The color experiments showed that the discoloration mechanism with the combined use of laccase enzyme, sodium hydrosulfite, and cellulose enzyme had a significant effect on the improvement of the lightness (L*) of the samples, as the lightness of the treated samples was improved by 101.18 percent and 55.79 percent in both printing and washing, respectively. Furthermore, examination of specimen color coordinates revealed that the hue of the treated samples was changed to blue and green, and the purity of color (C*) was improved. The increased moisture content and air permeability of the treated specimens suggested that the comfort of the jeans clothing provided by these treatment methods had improved. As a result, it should be noted that the mediating action of sodium hydrosulfite was significantly influential for discoloration of denim with the laccase enzyme.

scholarly journals Relationship Between Wood Colour of Seven Tropical Hardwood Species and Formaldehyde Emission of Plywood

2019 ◽  
Vol 8 (2S4) ◽  
pp. 520-523
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Extractive Content ◽  
Tropical Wood ◽  
Wood Colour ◽  
Tropical Hardwood ◽  
Hardwood Species ◽  
Colour Appearance

There are many factors that affect the formaldehyde emission from plywood such as wood species and moisture content. As for wood species, colour appearance was found to affect significantly the formaldehyde emission. Therefore, the effects of tropical wood species with different colour on the formaldehyde emission of manufactured plywood were studied and determined by the perforator and desiccator method. Veneer of seven wood species, namely Mempisang, Kedondong, Penarahan, Keledang, Rengas, Melembu and Ludai were chosen as samples. 3-ply plywood were manufactured using urea formaldehyde as binders. The formaldehyde emission of the produced plywood was tested using perforator method (EN 120) and desiccator method (MS 1787: Part 15). Colour of the wood veneers were measured using Brightness & Colour Meter through CIE L*a*b* system. Relationship between the wood colour and formaldehyde emission were determined. The results revealed that the formaldehyde emission increased as the lightness (L*) of the wood samples increased. This may be due to higher extractive content in darker coloured wood (low lightness) that acts as formaldehyde scavenger.

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