Die Geschwindigkeit der Wasserdampfsorption durch Holz

Christensen, G. N.; Kelsey, K. E.

doi:10.1007/bf02608810

Cited by 69 publications

(32 citation statements)

References 4 publications

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“…Among chemical components in cell walls, of the three major materials (lignin, hemicelluloses and cellulose) lignin has the lowest affinity for water and hemicelluloses the highest. The affinity of cellulose for water is between these two [10]. A lower hemicellulose content in tension wood was found in this study; see below, and also reported by Furuya et al [26].…”

Section: Growth Stress/physico-mechanical Propertiessupporting

confidence: 87%

Relationships between growth stress and wood properties in poplar I-69 (Populus deltoides Bartr. cv. “Lux” ex I-69/55)

et al. 2008

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-Six inclined poplar I-69 (Populus deltoids cv. I-69/55) trees were collected for studying the influence of growth stress level on wood properties. Growth stress indicator (GSI) was measured at eight positions around the periphery of each trunk at breast height and corresponding wood samples were obtained. Wood anatomical, physico-mechanical and chemical characteristics were measured, including cell diameter, fibre length, double wall thickness excluding the gelatinous layer, lumen diameter after gelatinous layer removal, proportion of wood tissues, basic density, FSP, MOE, compressive strength, shrinkage and chemical composition. Each property was regarded and discussed in relation to the growth stress level. Populus deltoids

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Section: Growth Stress/physico-mechanical Propertiessupporting

confidence: 87%

Relationships between growth stress and wood properties in poplar I-69 (Populus deltoides Bartr. cv. “Lux” ex I-69/55)

et al. 2008

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“…In contrast, Wadsö (1993) and Pfriem (2006) show clearly higher differences with a factor of about 10 between D US and D SS , which can be attributed to their modified method (simultaneous diffusion from two opposite sides of the specimen), which is clearly more influenced by the specimen thickness (Teischinger 1987). Additionally, D US is influenced by the MC difference of the experiment, which was already stated by Christensen and Kelsey (1959). The very low data by Pfriem et al (2010) may be ascribed to the above-mentioned influences.…”

Section: Combined Bound Water and Water Vapour Diffusionmentioning

confidence: 69%

Combined bound water and water vapour diffusion of Norway spruce and European beech in and between the principal anatomical directions

Sonderegger

Vecellio

Zwicker

et al. 2011

HFSG

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The combined bound water and water vapour diffusion of wood is of great interest in the field of building physics. Due to swelling stresses, the steady-state-determined diffusion coefficient clearly differs from the unsteady-state-determined diffusion coefficient. In this study, both diffusion coefficients and the water vapour resistance factor of Norway spruce (Picea abies wL.x Karst.) and European beech (Fagus sylvatica L.) were investigated for the principal anatomical directions (radial, tangential and longitudinal) and in 158 steps between these directions. The values were determined with the cup method as the basic principle. The unsteadystate-determined diffusion coefficient is, independent of the direction, about half that of the steady-state-determined diffusion coefficient. Both diffusion coefficients are about two to three times higher for spruce than for beech. They are up to 12 times higher in the longitudinal direction than perpendicular to the grain for spruce, and up to 15 times higher for beech. With increasing moisture content, the diffusion coefficients exponentially increase. The water vapour resistance factor shows converse values to the diffusion coefficients.

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“…It was assumed that the water vapor sorption in wood cell walls was composed of two processes ( Christensen and Kelsey 1959 ;Christensen 1965 ;Xie et al 2011a ;Hill et al 2012 ;Popescu et al 2014 ). The first stage was attributed to a process controlled by the diffusion of vapor into the polymer until a quasi-equilibrium condition is reached.…”

Section: Rate Of Sorptionmentioning

confidence: 99%

Effects of acetylation and formalization on the dynamic water vapor sorption behavior of wood

Himmel¹,

Mai

2014

Holzforschung

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The dynamic water vapor sorption of untreated, acetylated (W ac ), and formaldehyde-treated (W FA ) Scots pine ( Pinus sylvestris L.) sapwood was studied in a dynamic vapor sorption apparatus to assess the effects of cell wall bulking and cross-linking. Both modifications resulted in a considerable reduction of reduced equilibrium moisture content (EMC R ), the corresponding equilibrium times, and hysteresis in the hydroscopic range of wood. Acetylation reduced the adsorption and desorption of water at each given relative humidity (RH) step from 0% to 95% RH, whereas formalization affected the sorption behavior of wood solely above 20% RH. From 20% to 95% RH, the EMC ratio of W FA to its control steadily decreased, whereas the EMC ratio of W ac was still constant in this RH range. Below 20% RH, the sorption behavior of W ac was governed by hydroxyl blocking, whereas that of W FA was hardly influenced compared with the control. Above 20% RH, the sorption behavior of W ac was solely determined by cell wall bulking, whereas that of W FA was governed by the increased matrix stiffness due to the cross-linking of cell wall polymers.

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Die Geschwindigkeit der Wasserdampfsorption durch Holz

Cited by 69 publications

References 4 publications

Relationships between growth stress and wood properties in poplar I-69 (Populus deltoides Bartr. cv. “Lux” ex I-69/55)

Relationships between growth stress and wood properties in poplar I-69 (Populus deltoides Bartr. cv. “Lux” ex I-69/55)

Combined bound water and water vapour diffusion of Norway spruce and European beech in and between the principal anatomical directions

Effects of acetylation and formalization on the dynamic water vapor sorption behavior of wood

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