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  • 1
    Publication Date: 1970-01-01
    Print ISSN: 0018-3830
    Electronic ISSN: 1437-434X
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by De Gruyter
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 2 (1968), S. 166-176 
    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
    Description / Table of Contents: Zusammenfassung An Probespänen wurden Tracheidenlänge und Zell-Querabmessungen im Früh- und Spätholz von Loblolly pine (Pinus taeda L.) bestimmt und faktoriell gegen die Dichte, den Abstand von der Markröhre bzw. die Wuchsgeschwindigkeit abgegrenzt. Die “gereinigte” Beziehung jedes Faktors zur Fasermorphologie wird erörtert.
    Notes: Summary Earlywood and latewood tracheid length and transverse cellular dimensions of wood removed from stems of loblolly pine (Pinus taeda L.) and factorially segregated by specific gravity, rings from the pith, and growth rate were determined from sample chips. The independent relationships of each factor with fiber morphology are described.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 3 (1969), S. 287-300 
    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
    Description / Table of Contents: Zusammenfassung Die Qualität von 96 verschiedenen Zellstoffarten, alle im Scheiben-Refiner aus Hackschnitzeln unterschiedlicher Art hergestellt, wurde mit Hilfe des Faser-Form-Faktors S und des Faser-Längen-Faktors L bestimmt. S wurde in Einheiten des Mahlgrades nach Canadian Standard Freeness der 48/100 Faser-Längen-Fraktion bestimmt. S ist als Parameter umgekehrt proportional zur spezifischen Oberfläche. L ist der gewichtsmäßig bestimmte Anteil an Zellstoff, der ein 48-Mesh-Sieb nicht mehr passiert und gibt gleichzeitig gewichtsmäßig die Verteilung der Faserlängen in der Gesamtmenge des Zellstoffes an. Durch S und L werden 83% der Eigenschaftsschwankungen innerhalb der Prüfblätter erklärt. Diese Eigenschaften konnten durch Zellstoff mit niedrigeren S-Werten und relativ hohen L-Werten verbessert werden. Sowohl S als auch L wurden mit der spezifischen Refiner-Leistung und mit der Holzqualität korreliert. S nahm mit ansteigender Dichte der unbehandelten Hackschnitzel und mit ansteigender Jahrringzahl je Zuwachseinheit zu, fiel dagegen mit ansteigendem Spätholzanteil und Refiner-Leistung ab. Dagegen nahm L mit ansteigender Refinerleistung, Jahrringzahl je Zuwachseinheit und Dichte der unbehandelten Hackschnitzel ab, stieg jedoch mit zunehmendem Spätholzanteil an.
    Notes: Summary Pupl quality, in terms of a fiber shape factor S and a fiber length factor L, was determined for 96 pulps disk-refined from chips of varying characteristics. S was evaluated in terms of the Canadian Standard Freeness of the 48/100 fiber length fraction and is a parameter inversely proportional to specific surface. L is the percentage, by weight, of pulp retained on a 48-mesh screen and reflects the distribution by weight of fiber length in the whole pulp. S and L accounted for as much as 83 percent of the variation in handsheet properties. Properties were improved by using pulps displaying low values of S and relatively high values of L. Both S and L were related to specific refining energy and wood quality. S increased with increasing unextracted chip specific gravity and rings per inch of growth rate but decreased with increasing latewood content and refining energy. L decreased with increasing refining energy, rings per inch of growth rate, and unextracted chip specific gravity but increased with increasing latewood.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 2 (1968), S. 233-240 
    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
    Description / Table of Contents: Zusammenfassung Aus Probespänen von Loblolly pine (Pinus taeda L.) wurden die alpha-Cellulose, Hemicellulose, Holocellulose, Lignin und Extraktstoffe bestimmt und faktorenanalytisch gegen die Dichte, den Jahrringabstand vom Mark und die Wuchsgeschwindigkeit abgegrenzt. Die „gereinigten” Beziehungen jedes Faktors zur chemischen Zusammensetzung des Holzes werden beschrieben. In the research reported here, the chemical composition of a sample of loblolly pine wood was analyzed in relation to three readily measured gross wood characteristics: specific gravity, growth rate, and distance from the pith. As in a previous study relating fiber morphology to these three properties [McMillin, 1968], wood was removed from many stems and stratified by two densities and two growth rates at each of three radial positions in the stem. Thus, the factorial design permitted isolation of the independent relationships of each factor with various chemical components. Characterizing wood types in this way is quite distinct from studying variations in the chemical composition of stems.
    Notes: Summary The alpha-cellulose, hemicellulose, holocellulose, lignin, and extractive contents of wood removed from stems of loblolly pine (Pinus taeda L.) and factorially segregated by specific gravity, rings from the pith, and growth rate were determined from sample chips. The independent relationships of each factor with chemical composition are described.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 3 (1969), S. 139-149 
    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
    Description / Table of Contents: Zusammenfassung Berstdruck, Reißlänge und Blattdichte vonPinus taeda L., wurden durch Verwendung von Refiner-Fasern aus Holz, das lange Tracheiden mit geringem Durchmesser und dicken Wänden besitzt, verbessert. Zur Verbesserung des Reißfaktors waren ausschließlich dickwandige Tracheiden mit geringem Durchmesser erforderlich. Eine Spannungsanalyse zeigte, daß dickwandige Zellen mit kleinem Außendurchmesser durch diagonale Zug- oder parallele Scherbeanspruchung in Abhängigkeit vom Fibrillenanstiegswinkel während der Torsionsbelastung im Refiner reißen. Durch diesen Bruchvorgang ergeben sich bandförmige Bruchstücke, die nachgewiesenermaßen notwendig sind, um den inneren Zusammenhalt für die Festigkeitsentwicklung in mechanischem Zellstoff zu ermöglichen. Im Gegensatz hierzu brechen dünnwandige Zellen mit kleinem Außendurchmesser mehr durch diagonale Druckbeanspruchung und es ergeben sich nur wenige Bänder. Lange Fasern sind insofern erwünschter als kurze, da sie zu höheren Festigkeiten führen und eine höhere Wahrscheinlichkeit ihrer axialen Ausrichtung zwischen den Refinerscheiben besteht.
    Notes: Summary InPinus taeda L., burst, breaking length, and sheet density were improved by using fiber refined from wood having long, narrow-diameter tracheids with thick walls. Only narrowdiameter tracheids with thick walls were required to improve tear factor. A theoretical stress analysis revealed that thick-walled cells of small outside diameter fail by diagonal tension or parallel shear, depending on the fibril angle, while under torsional stress during refining. Such failures result in ribbon-like fragments which research elsewhere has demonstrated to provide the coherence necessary for strength development in mechanical pulps. In contrast, thinwalled cells of small outside diameter fail by diagonal compression and yield few ribbons. Long fibers are more desirable than short fibers because of greater induced stresses and improved chances of axial alignment between the disks.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 3 (1969), S. 232-238 
    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
    Description / Table of Contents: Zusammenfassung Berstzahl und Reißfestigkeit der Blätter von 48 verschiedenen Zellstoffen aus scheibengemahlenen Spänen mit unterschiedlichen chemischen Bestandteilen verringerten sich mit ansteigendem Extraktstoffgehalt; die davon unabhängigen Einflüsse des Faseraufbaues sind dabei berücksichtigt. Diese Tatsache wird der verminderten Bindungskraft zugeschrieben, verursacht durch die herabgesetzte Oberflächenspannung und die Blockierung von Bindungsstellen an den Faseroberflächen.
    Notes: Summary Burst and tear strengths of handsheets made from 48 pulps disk-refined from chips of varying chemical composition decreased with increasing extractive content after the independent effects of fiber morphology were specified. This result was attributed to lessened bond strength caused by reduced surface tension forces and blocking of reactive sites on the fiber surfaces.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 7 (1973), S. 251-255 
    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 Fibril angles were greater for earlywood (avg. 33.4°) than for latewood tracheids (avg. 26.9°). For earlywood, fibril angle did not differ between growth rates when the specific gravity was low (avg. 33.3°). When the specific gravity was high, wood of fast growth had a higher fibril angle (avg. 35.1°) than wood of slow growth (avg. 32.0°). No differences were detected between core, middle, and outer wood. In latewood tracheids, fibril angles were greater in corewood (avg. 28.0°) than in middle or outer wood (avg. 26.3°). For whole wood (a weighted average of earlywood and latewood), fibril angle averaged 30.7° and was greater in corewood (avg. 32.2°) than in middle or outer wood (avg. 29.9°).
    Type of Medium: Electronic Resource
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