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Vliv jednotlivých fázi výrobního procesu Lignamonu a jejich vzájemných interakcí na výslednou odolnost vůči dřevokazným houbám
Nevrlý, Ondřej
In this work is discussed about material Lignamon, which has been industrially produced in the former Czechoslovakia since the 1970s. The production of this material, mainly from beechwood, combines plasticization with gaseous ammonia, densification of material by hydraulic press and heat stabilization at 180 ° C. The aim of this work is to determine the effect of these processes on the resulting resistance to wood-decaying fungi. Lignamon has a very high resistance to wood-decaying fungi and is classified as very durable according to EN 350 - 1. For each phase of the Lignamon process, samples were produced to best illustrate the changes that take place during the given phase in the wood. In particular, sample sets treated with ammonia gas, densified samples, heat-treated samples, and samples on which a combination of ammonia gas impregnation and thermal modification were performed. The resistance to wood-decaying fungi have been tested according to EN 113, including a set of Lignamon samples. The results of this test were statistically evaluated and it was found that ammonia treatment has the greatest influence on the durability of Lignamon, as well as the heat treatment and not so significantly densification. Individually, however, none of these modifications cause wood resistance to wood-decaying fungi as their combination in the production process of Lignamon.
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Srovnání přirozené trvanlivosti a vybraných vlhkostních vlastností dřeva subfosilního dubu s dřevem dubu recentního
Nevrlý, Ondřej
This work should be used to determine differences between the properties of recent subfossil and oak wood. For this work, there are available samples of four historical periods. The first period is the present, and therefore, these data should be consistent with the literature and serve as well as verifying the accuracy of the procedure and methodology for the acquisition of data. Then there are available subfossil oak samples from three periods, 1131-804 BC., 208 BC. - 137 and after the year 1018th. It was investigated experimentally durability of wood. Samples were subjected to the test of durability against wood--destroying fungi according to EN 113. Used decaying fungi are Trametes versicolor, Laetiporus sulphureus and Poria placenta. Further samples were devided into durability classes according to EN 350--1. It was found that subfossil oak wood resistance to wood--destroying fungi decreased. Furthermore there was investigated selected moisture characteristics and also some other physical properties of oak. Oak wood contains a high amount of tannins, which gives it extremely high durability and resistance. So now we are finding an oak tree trunks which are up to 8,500 years old.
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