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Wyświetlanie 1-2 z 2
Tytuł:
Seasoning technologies of Gmelina arborea Roxb. lumber species grown at Bonga, SNNP, Ethiopia
Autorzy:
Desalegn, Getachew
Kaba, Gemechu
Tesfaye, Anteneh
Amanuel, Saifu
Powiązania:
https://bibliotekanauki.pl/articles/1031783.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Defects
Gmelina arborea
density
lumber quality
seasoning defects
shrinkage and uses
Opis:
Quality and performance of wood and wood-based products have been seriously affected by the major factors, among which moisture content (MC), inappropriate drying (seasoning) and density are the preceding ones. A study was conducted on Gmelina arborea lumber with the main objective of determining some imperative seasoning and density characteristics of the lumber that will help determine its wood quality and decide proper utilization. Gmelina arborea logs were harvested from Bonga trial site of Central Ethiopian Environment and Forest Research Center (CEE-FRC). The experimental design for seasoning and density was complete randomized design. The experiments were conducted in air and kiln seasoning methods. Mean initial moisture content (IMC) of samples were determined using oven and MC for air seasoning stack was 143.80%, while for kiln seasoning was 120.19%. The final MC to reach to about 12% MC in air took 210 days, while kiln seasoning took 13.5 days. Kiln seasoning rate of Gmelina arborea lumber was 15 times faster than air seasoning. The species was classified as slow and fairly rapid air and kiln seasoning lumber species, respectively. When Gmelina arborea lumber seasoned from green to 12% MC, mean shrinkage (%) characteristic values: Tangential (3.63%), radial 1.58%), and volumetric (5.11 %). Mean density of Gmelina arborea lumber species at green (initial), basic and oven dried and at 12% MC was 940,400, 430 and 420 kg/m3, respectively. The density at 12% MC, (420 kg/m3) classified as light density lumber species. Gmelinaarboreashown good quality lumber characteristics, comparable with many indigenous and homegrown exotic lumber species in density, seasoning rate and shrinkage characteristics.
Źródło:
World News of Natural Sciences; 2020, 29, 3; 269-281
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seasoning Characteristics and Potential uses of Eucalyptus pilularis, Eucalyptus viminalis and Trichilia dregeana lumber tree species
Autorzy:
Kaba, Gemechu
Desalegn, Getachew
Powiązania:
https://bibliotekanauki.pl/articles/1031739.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Eucalyptus pilularis
Eucalyptus viminalis
Lumber quality
Trichilia dregeana
moisture content
seasoning
seasoning defects
shrinkage characteristics
timber species
Opis:
Technical information on lumber seasoning, moisture content (MC), density, mechanical, workability and chemical characteristics would strongly determine rational utilization of each lumber species. A study was conducted on home-grown two Eucalyptus species (Eucalyptus pilularis and Eucalyptus viminalis) and one indigenous (Trichilia dregeana) timbers with the main objective of determining some characteristics of lumber that will indicate quality and proper utilization. Study species were harvested from Shashemene, Asella and Arjo sites, respectively. The experimental design for seasoning and density was complete randomized design, a factorial experiment. The experiments were conducted using air and kiln seasoning methods. To determine initial moisture content oven drying method was used. The mean initial MC for the three timber species were 48.25%, 56.1% and 65.45%, respectively. The species were classified as very rapid seasoning rate during kiln seasoning. The mean shrinkage values were Tangential (6.31, 4.94 and 4.43%), radial (3.4, 4.02 and 2.10%) volumetric (9.46, 8.6 and 6.37%), when they seasoned from green to 12% MC, respectively. Seasoning defects such as cup, bow, crook, end split, surface and end-checks were observed, though the extent varies with species. The density of E. pilulalris, E. viminalis and T. dregeana at 12% MC was 780, 810 and 530 Kg/m3, respectively. The one-way analysis of variance indicated that there was significant difference (P>0.001) in initial MC, final MC, density values at different MC and shrinkage characteristics. They revealed good lumber characteristics and qualities, comparable with many indigenous and home-grown exotic timber species in density, seasoning rate and shrinkage. The tree species have to be well managed, properly harvested and sawn. Boards have to be properly stacked and seasoned to about 12% MC, with kiln and air seasoning methods that can help to minimize seasoning time, seasoning defects, shrinkage characteristics and increase quality.
Źródło:
World News of Natural Sciences; 2020, 29, 3; 162-178
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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