نتایج جستجو برای: wood density

تعداد نتایج: 447006  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی 1391

in this study, the effects of oleothermal modification on physical and mechanical peroperties of fir wood (abeis sp.) blocks were examined. at first, some blocks of fir wood with 5 × 20 × 120 cm dimensions were prepared. the blocks were treated in soybean oil. the effects of 3 factors such as treatments temperature (180and 200 °c), holding time (12 and 15 h) and initial moisture content of wood...

Journal: :journal of agricultural science and technology 2013
a. enayati f. eslah e. farhid

the application of stepwise multivariate-linear regression models for determination of particleboard properties based on structural factors was studied. poplar (populus alba), beech (fagus orientaleis) and hornbeam wood (carpinus betulus) with dry density of 460, 630 and 790 kg/m3,respectively, were used as raw materials. three levels of boards target density (520, 620 and 720 kg m-3) and urea ...

Journal: :پژوهش های علوم و فناوری چوب و جنگل 0

bending and compression strength of paulownia fortunie wood grown in educational and research forest located at shastkalate, gorgan were studied. paulownia trees were selected among five years old plantation. sampling spot was conducted following standard procedure. trees were cut into logs, which were then cut into 6 cm thickness wood blocks based on geographic directions. wood blocks were div...

2011
Hamid Reza Naji Mohd. Hamami Sahri Tadashi Nobuchi Suhaimi Bakar

Inter-clonal and intra-clonal wood properties and their variations from pith to bark were evaluated for wood density and anatomical features on rubber wood (Hevea brasiliensis Muell. Arg) from a 9-year-old plantation with planting densities of 500 and 2000 trees per hectare comprised of clones RRIM 2020 and RRIM 2025. Planting density had uneven effects on wood density and wood cell features. I...

2016
Edward Missanjo Junji Matsumura Eric Jokela

Successful development of an appropriate tree breeding strategy and wood utilization requires information on wood properties. This study was therefore conducted to assess wood density and mechanical properties of Pinus kesiya Royle ex Gordon grown in Malawi. Wood samples from six families of P. kesiya at the age of 30 years were used for the study. The estimated mean wood density, Modulus of El...

2010
Markku Larjavaara Helene C. Muller-Landau

1. Current thinking holds that wood density mediates a tradeoff between strength and economy of construction, with higher wood density providing higher strength but at higher cost. 2. Yet the further away wood fibres are from the central axis of the trunk, the more they increase the strength of the trunk; thus, a fat trunk of low-density wood can achieve greater strength at lower construction c...

2003
Richard P. Guyette Mike Stambaugh

Large wood of oak trees (Quercus spp.) has resided in the streams and sediments of north Missouri, USA for many thousands of years. This wood affords the opportunity to compare a chronosequence of differences in wood density over a very long period. We analyzed the relationship between the age (residence time) and density of heartwood from oak boles using tree-ring and 14C dating methods and di...

A. Dorostkar A. Rafighi M. Madhoushi

In this research, the effect of wood species and particle size on mechanicalproperties of wood plastic composites (WPC) made of fir (Abies alba) and beech(Fagus orientalis L.) sawdust and high density polyethylene (HDPE) wereinvestigated. Wood plastic composite (WPC) were made with 30% HDPE in abatch process at 185˚C, at two particle sizes of 40 mesh and 80 mesh. Maleicanhydride polypropylene (...

2011
Bilgin Guller Kani Isik Senay Cetinay

Trees in two provenance-progeny experimental sites of Pinus brutia Ten. were sampled to study variation in wood density and its components among and within six populations and to estimate heritability of wood density and ring components. Wood increment cores (12 mm thick) were collected from 29-year-old trees at breast height. A total of 1023 wood strips were scanned with the X-ray densitometry...

Journal: :Ecological applications : a publication of the Ecological Society of America 2006
Jérôme Chave Helene C Muller-Landau Timothy R Baker Tomás A Easdale Hans ter Steege Campbell O Webb

Wood density is a crucial variable in carbon accounting programs of both secondary and old-growth tropical forests. It also is the best single descriptor of wood: it correlates with numerous morphological, mechanical, physiological, and ecological properties. To explore the extent to which wood density could be estimated for rare or poorly censused taxa, and possible sources of variation in thi...

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