نتایج جستجو برای: kraft
تعداد نتایج: 2427 فیلتر نتایج به سال:
Enzymatic polymerization of lignin is an environmentally-friendly and sustainable method that is investigated for its potential in opening-up new applications of one of the most abundant biopolymers on our planet. In this work, the laccase from Myceliophthora thermophila was successfully immobilized onto Accurel MP1000 beads (67% of protein bound to the polymeric carrier) and the biocatalyzed o...
Kraft pulping is the dominant process currently used to produce chemical pulps, and has been applied for more than 130 years. A large number of studies have been conducted to gain a better understanding of the delignification kinetics as well as the reactions of the wood components being dissolved during the cooking process. Nevertheless, these remain far from being well understood in detail du...
The authors studied a cohort of 30,157 male pulp and paper workers in British Columbia, Canada. Of these, 20,373 worked in kraft mills only, 5,249 in sulfite mills only, and 4,535 in both kraft and sulfite mills. All workers with at least 1 year of employment on January 1, 1950, or thereafter until December 31, 1992, were studied. Standardized mortality ratios (SMRs) were used to compare the mo...
Chemical modification of eucalypt lignin was investigated during kraft pulping and chlorine-free bleaching by comparing milled wood lignin, kraft lignin, and pulp enzymatic residual lignins. The syringyl-to-guaiacyl ratio (S/G) from analytical pyrolysis slightly changed during pulping and bleaching (S/G, 3-4) but was higher in the kraft lignin. Semiquantitative heteronuclear single quantum corr...
Das Robotersystem für die Transkranielle Magnetstimulation (TMS) ermöglicht eine präzise und wiederholbare Positionierung der TMS-Spule auf dem Kopf des Patienten. Um einen sicheren Einsatz des Roboters zu gewährleisten, ist oftmals eine manuelle Vorpositionierung des Roboters nötig, um einen gewünschten Stimulationspunkt zu erreichen. Mittels der Kraft-Momenten-Steuerung (KMS) ist es möglich d...
In an attempt to explain variations in delignification behaviors among different hardwood species, the kraft pulping delignification rates of Eucalyptus urograndis, E. nitens, E. globulus, sweet gum, maple, red oak, birch, red alder, cottonwood, and acacia were obtained and correlated with their respective lignin chemical structures. Since H-factor for hardwood is calculated based on the softwo...
Common metrics for evaluating the efficiency of oxygen delignification include the kappa number and Klason lignin content. As a change in xylan content often leads to a change in HexA content, the kappa number must be corrected for the HexA contribution before evaluating the degree of oxygen delignification when trying to understand the process in detail. Questions could also be raised about th...
Kraft’s inequality [9] is essential for the classical theory of noiseless coding [1, 8]. In algorithmic information theory [5, 7, 2] one needs an extension of Kraft’s condition from finite sets to (infinite) recursively enumerable sets. This extension, known as Kraft-Chaitin Theorem, was obtained by Chaitin in his seminal paper [4] (see also, [3, 2], [10]). The aim of this note is to offer a si...
A series of activated carbons (ACs) were prepared by K2CO3 activation from kraft lignin (KL) that was recovered from papermaking black liquor. The effects of process parameters such as the activation temperature (AT), activated period, K2CO3 to KL mass ratio, and N2 flow rate on the characteristics of the final product were determined. The ACs were characterized using nitrogen adsorption, morph...
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