Strukturne značilnosti in fizikalno-mehanske lastnosti juvenilnega, adultnega in poranitvenega lesa črnega bora (Pinus nigra Arn.)

diplomsko delo (visokošolski strokovni študij)

Andrej Grahor (Author), Katarina Čufar (Reviewer), Željko Gorišek (Mentor), Primož Oven (Co-mentor)

Abstract

Na lesu črnega bora (Pinus nigra Arn.) smo primerjali gostoto (ru = 12%), ravnovesne vlažnosti lesa (ur), sušilnične in totalne skrčke (ß), prečno krčitveno anizotropijo (An), diferencialno nabrekanje (q), koeficient nabrekanja (h), sorpcijski kvocient (s), tlačno (vzporedno z vlakni) in upogibno trdnost, ter modul elastičnosti (Emodul) pri juvenilnem, adultnemin poranitvenem lesu. Gostota (pri MC = 12%) juvenilnega, kakor tudi poranitvenega lesa, je bila višja od gostote adultnega. Vzrok za višjo gostoto juvenilnega lesa je bila povečana vsebnost smole: ta je vplivala tudi na navidezno višjo ravnovesno vlažnost juvenilnega lesa v primerjavi z adultnim oziroma poranitvenim: med slednjima pa ni bilo opaznih razlik. Značilnih razlik pri krčenju (podobno velja tudi za kazalnike dimenzijske stabilnosti) v radialni in longitudinalni smeri med normalnim in poranitvenim lesom ni bilo, kar pa ne velja za krčenje v tangencialni smeri, ki je bilo pri normalnem lesu večje. Juvenilni les je imel v vseh 3 smereh manjše skrčke od normalnega in poranitvenega. Prečna krčitvena anizotropija je bila največja pri juvenilnem lesu, med ostalima kategorijama pa ni bilo značilnih razlik. Tlačna trdnost vzporedno z vlakni in modul elastičnosti adultnega lesa sta bila večja kot pri poranitvenem lesu, medtem ko je bila upogibna trdnost med obema kategorijama primerljiva. Najslabše mehanske lastnosti (tlačno in upogibno trdnost ter modul elastičnosti) je imel juvenilni les.

Keywords

juvenilni les;adultni les;poranitveni les;krčenje;dimenzijska stabilnost;mehanske lastnosti;Pinus nigra Arn.;

Data

Language:	Slovenian
Year of publishing:	2007
Source:	Ljubljana
Typology:	2.11 - Undergraduate Thesis
Organization:	UL BF - Biotechnical Faculty
Publisher:	[A. Grahor]
UDC:	630*811
COBISS:	1472393
Views:	1305
Downloads:	416
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Structural characteristics and physical-mechanical properties of juvenile, adult and wound pine wood (Pinus nigra Arn.)
Secondary abstract:	Density (ru = 12%), equilibrium moisture content (ur), drying and total shrinkage (ß), transversal shrinkage anisotropy (An), ratio of swelling (q), coefficient of swelling (h), ratio of sorption (s), compressive (parallel to grain) and bending strength, and the modulus of elasticity (Emodul) of juvenile, adult and wound of black pine wood (Pinus nigra Arn.) were compared. The density of juvenile wood (at MC = 12%), as well as of wound wood, was higher than the density of adult wood due to high resin content. This was also the reason that the equilibrium moisture content of juvenile wood was higher than those of adult wood and wound wood; the differences between the latter being negligible. There were no typical characteristics in shrinkage (the same pattern was observed also in dimensional stability) in the radial and longitudinal directions between the normal and juvenile wood, which could not be said for the shrinkage in tangential direction - it was more intensive in normal wood. Juvenile wood had lower shrinkage compared to normal and wound wood in all 3 directions. The transversal shrinkage anisotropy was the highest in juvenile wood, while the differences between the other 2 categories were not characteristic. The compressive strength parallel to grain and the modulus of elasticity of adult wood were higher than those of wound wood, while the bending strength between the 2 categories was comparable. Juvenile wood had the lowest mechanical properties (compressive and bending strength, and the modulus of elasticity).
Secondary keywords:	wood;juvenile wood;adult wood;wound;schrinkage;dimensional stability;mechanical properties;Pinus nigra Arn.;
Type (COBISS):	Undergraduate thesis
Thesis comment:	Diplomsko delo, Univ. v Ljubljani, Biotehniška fakulteta, Oddelek za lesarstvo
Pages:	XIV, 56 f., [32 f. pril.]
Keywords (UDC):	applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;agriculture and related sciences and techniques;forestry;farming;wildlife exploitation;kmetijstvo ter sorodne vede in tehnologije;forestry;gozdarstvo;forest products and their utilization;gozdni proizvodi in njihova uporaba;
ID:	21059