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  • 1970-1974  (5)
  • 1940-1944  (3)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 45 (1941), S. 43-54 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry 32 (1940), S. 809-813 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 45 (1941), S. 1137-1138 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 6 (1972), S. 263-271 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Measurements of the gas pressure required to displace water and allow gas bubbles to start continuously passing through the void structure of hardwood cross sections varying in thickness from 0.1 ... 10.0 cm have been used to calculate the maximum effective opening diameters. These diameters decrease with an increase in the thickness of the cross sections, as is the case for softwoods. Extrapolation of diameter—thickness plots to zero thickness gives the maximum vessel diameters, which agree well with microscopically determined values. The relatively small decrease in the maximum effective opening diameters with increasing thickness of the cross sections for most of the sapwood samples tested is due to irregularities in the vessel diameters and presence of perforation plates at the ends of the vessel segments. The decrease in the maximum effective opening diameter with an increase in the thickness of the cross sections is greater for the heartwood than for the sapwood. The ratio of the sapwood to the heartwood values tends to become constant between cross section thicknesses of 2.5 and 5.0 cm. This ratio was small for tyloses free northern red oak but appreciable for the hardwoods containing tyloses in the heartwood. Air drying followed by oven drying and resaturating of the specimens with water caused only small variable changes in the maximum effective opening diameters that were within the range of experimental accuracy of the measurements (approximately 5%).
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 7 (1973), S. 285-296 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Oven dry highly evacuated sticks of the sapwood of various hardwoods, 40 cm long by 1.0 to 1.2 cm in the radial and tangential directions, took up water to the extent of 44 to 82% of saturation by capillary flow in one minute. Heartwood sticks took up 15 to 38% of saturation in one minute. The initial rapid penetration was followed by a penetration in which the take up increase directly with the square root of elapsed time. In this range, the slope of toluene take up plots was about twice that of the water take up. This is close to the theoratical value on the basis of viscous flow control. The linear portion of the plots is followed by a curvilinear decrease in rate of take up to a final equilibrium value. Water take ups approached 100% of the theoretical values. Times to 0.99 of theoretical filling with water varied from 9 minutes for tupelo gum sapwood to 14.6 to 17.3 days for white oak heartwood. Complete filling with toluene was never attained. Diffuse porous hardwoods filled to the extent of 93.5 to 96.5% of saturation. Ring porous oaks filled to the extent of 88 to 92%, the lower values being for heartwood. Edge coating of the sapwood of yellow poplar and yellow birch with epoxy glue reduced the rate of penetration only slightly. End coating reduced the rate to a higher degree. Moisture gradients in the fiber direction for tyloses-free hardwoods were negligible at various stages of penetration, indicating that filling of the vessels was practically instantaneous. White oak heartwood gave an initial longitudinal gradient followed by a negligible gradient, indicating that longitudinal penetration is primarily through the lumen of the fibers rather than continously through the vessels. Longitudinal penetration was calculated to be 31.5 times as deep as transverse penetration in 100 minutes and 33.3 times as deep in 25 minutes for white oak heartwood. The ratios are of the same order of magnitude as for Loblolly pine. In both cases the ratios are smaller than values calculated from the fiber dimensions alone as ray cell penetration and cross grain effects tend to lower the ratios.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 8 (1974), S. 300-306 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Mono and diammonium acid phosphate, ammonium sulfamate, and sodium silicate were compared with polyethylene glycol-1000 as bulking dimension stabilizing agents using Engelmann spruce cross sectional wafers. Limiting antiswell efficiencies are equal to the volume fraction of chemical in a saturated solution. The experimental antiswell efficiencies due to bulking are the percent increase in the dry cross sectional area of the wafers caused by deposition of dry chemical within the cell walls divided by the percent swelling in water. These values for the phosphates, the sulfamate, and the polyethylene glycol approach the limiting values from solubility indicating that chemical continues to diffuse into the cell walls as the wood is dried to virtually attain a saturated solution within that structure. The sodium silicate gave an apparent negative antiswell efficiency as collapse of the fibers on drying exceeded the actual bulking. Antiswell efficiencies between 0 and 30% relative humidity, 0 and 90% relative humidity and 30 and 90% relative humidity were in general still lower. This is largely due to the treated systems taking up more water than the controls, especially at the higher relative humidity. Antiswell efficiencies for the mono ammonium acid phosphate ranged from 20 to 27%, for the diammonium acid phosphate from 28 to 37%, the ammonium sulfamate from 51 to 66% and the polyethylene glycol from 63 to 77%.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Measurements of the gas pressure just required to displace saturating liquids and allow a slow continuous stream of gas to pass through ponderosa pine and redwood cross sections over a broad range of thicknesses at varying distances from pith to bark, together with the surface tensions of the liquids, have been used to calculate: (1) maximum lumen radii and maximum fiber lengths from the data for the thinner specimens, and (2) maximum pit pore radii for the specimens thicker than the maximum fiber lengths. Maximum lumen radii and maximum fiber lengths both increase from pith to bark and with increasing height in the tree. Maximum effective pit pore radii increase from the pith to the sapwood transition point, then increase abruptly followed by a variable zone in the sapwood. Displacement of water or a wetting agent solution gave comparable results for never-dried wood. Drying from water and resoaking reduced the maximum effective pit pore size. Drying from a wetting agent soaked condition followed by resoaking reduced the loss in permeability but not to the degree anticipated. ponderosa pine sapwood, that had been exposed to bacterial action, showed a large increase in the maximum effective communicating opening sizes.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 7 (1973), S. 212-217 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Measurements of the air pressure required to initially displace a saturating liquid and allow a slow continuous stream of air bubbles to pass through wood cross sections of different thickness, together with the equilibrium surface tension of the saturating liquid, make it possible to calculate the maximum effective opening radii. Previous measurements were made for wood as a whole over complete annual rings. Measurements reported here were made separately for earlywood and latewood. Extrapolating plots of the maximum effective opening radius-cross section thickness, for thicknesses below the maximum fiber length, to zero thickness gave maximum lumen radii of 16 μm for the earlywood and 10.3 μm for the latewood. The values are only slightly greater than the calculated average values. Extrapolating the plots in the opposite direction to zero opening radius gave approximate maximum lumen or fiber lengths for the earlywood of 6 mm and for the latewood of 5 mm. The maximum effective opening radii for cross sections thicker than the maximum fiber length give maximum effective communicating pore radii. These values continue to decrease, with increasing thickness of the cross sections due to the decreasing probability of the largest openings falling in any one series path through the structures. The maximum effective pit pore radius for passage through fifty pits in series was 0.8 μm for the earlywood and 0.28 μm for the latewood.
    Type of Medium: Electronic Resource
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