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Gewählte Master / Diploma Thesis:

Marko Kovacevic (2017): Drying properties of wet-glued large-sized construction spruce lumber.
Master / Diploma Thesis - Institut für Holztechnologie und Nachwachsende Rohstoffe, BOKU-Universität für Bodenkultur, pp 62 (53 ohne Inhaltsverzeichnis, table of content). UB BOKU obvsg FullText

Data Source: ZID Abstracts
Abstract:
The thesis focuses on convective drying of large-sized cross-section wet-glued construction spruce lumber using conventional temperatures. The objective is primarily to determine whether drying of this new product is possible using traditional drying methods, and if so whether it is feasible to achieve target moisture content in comparable time to traditional, non-glued lumber. Much of time and attention was dedicated to observing and analyzing moisture gradients of non-glued and glued timber, in order to compare their drying manner and speed as well as identifying flaws in the traditional drying schedule. Twist and bow deformation were measured and examined, along with cross-sectional deformation and consequential material loss. At the end of each drying schedule a measurement of checks was taken and further analyzed for both non-glued and glued tested units. The results showed quite a similar drying manner of non-glued and glued timbers. Very similar drying rates of both groups of timbers were recorded for units with similar basic density, initial moisture content and moisture distribution. However, these three parameters considerably influenced the drying rate in both groups. Alternating position of the sections in glued units had a very positive effect on the shape stability of timbers. The negative effect of pith was almost completely neutralized. Both twist and bow deformation were lower compared to non-glued units. Moreover, considerably lesser cross-sectional deformation of glued units was recorded. The mean loss of dried material solely due to this deformation was 2,7 % lower for glued timbers. Quite a high amount of checks on both non-glued and glued timbers was observed due to rather severe drying schedules. In general, non-glued timbers were less prone to checking than glued ones. The increase in checks, however, was not major. On the other hand, non-glued timbers had wider checks in general, reaching up to 10 mm for timbers containing pith.

Beurteilende(r): Teischinger Alfred
1.Mitwirkender: Stingl Robert

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