نتایج جستجو برای: beech wood

تعداد نتایج: 42160  

Journal: :Journal of structural biology 1999
H Lichtenegger A Reiterer S E Stanzl-Tschegg P Fratzl

Position-resolved small-angle X-ray scattering was used to investigate the nanostructure of the wood cell wall in two softwood species (Norwegian spruce and Scots pine) and two hardwood species (pedunculate oak and copper beech). The tilt angle of the cellulose fibrils in the wood cell wall versus the longitudinal cell axis (microfibril angle) was systematically studied over a wide range of ann...

2017
Nikola Patzel Jean-François Ponge

A non-random sampling design allowed to distinguish within a virgin beech ecosystem two main components of humus profile heterogeneity. The stratification of the profile into horizons reflects changes in the composition of the soil/litter matrix occurring under the influence of the anisotropic deposition of leaf and wood litter and the stratified occurrence of soil organisms (roots, microbes, a...

Journal: :journal of agricultural science and technology 2010
b. mohebby

acetylation is a chemical modification of wood to enhance its properties. ir-spectroscopy is a useful technique for proofing chemical bondings in wood and the at-tenuated total reflection (atr) infrared spectroscopy technique was applied as an eas-ier technique over other ir-spectroscopies. in this research, different degrees of acetyla-tion, weight percentage gains (wpgs) in beech and pine min...

2013
Andrzej Kusiak

The thermal properties of wood in the green state have been determined by the transient plane source (TPS) technique. Data are presented on thermal conductivity ( λ ), heat capacity ( C ), and thermal diffusivity ( κ ) at moisture contents (MCs) above the fiber saturation point, which are based on measurements using the HotDisk ® apparatus. Four wood species (Douglas fir, beech, birch, and spru...

A. E. Bonyad R. Naghdi, S. Mohammadi Limaei, S. Namdari

The aim of this study was to determine the optimal cutting cycle in an uneven-aged beech forest in the North of Iran. First of all, a logistic growth model was determined for an uneven aged forest. Then, the stumpage price was predicted via an autoregressive model. The average stumpage price of beech was derived from actual timber, round wood, fire and pulpwood prices at road side minus the var...

2017
Constantinos Katsimpouras Konstantinos G. Kalogiannis Aggeliki Kalogianni Angelos A. Lappas Evangelos Topakas

BACKGROUND Lignocellulosic biomass is an abundant and inexpensive resource for biofuel production. Alongside its biotechnological conversion, pretreatment is essential to enable efficient enzymatic hydrolysis by making cellulose susceptible to cellulases. Wet oxidation of biomass, such as acetone/water oxidation, that employs hot acetone, water, and oxygen, has been found to be an attractive pr...

Journal: :جنگل و فرآورده های چوب 0
الهام نوروزی - بهبود محبی دانشگاه تربیت مدرس

abstract:any effects of wood coating with different compounds as nano-zinc, nano-chitosan, chitosan, silicon oil and flaxseed oil on surface properties as; wood color change, surface roughness and wettability were studied in the current research work. for this purpose, sample boards of beech wood were cut into sizes of 2×10×20cm. the specimens were coated with the noticed coatings and tested fo...

Journal: :The Annals of occupational hygiene 2009
Giampaolo Gori Mariella Carrieri Maria Luisa Scapellato Giorgio Parvoli Daniela Ferrara Rocco Rella Alberto Sturaro Giovanni Battista Bartolucci

A new gas chromatographic/mass spectrometric (GC/MS) method was developed to detect 2-methylanthraquinone (2-MeA) in wood dust. 2-MeA is present in teak wood (a suspected human carcinogen) but not in oak, beech, mahogany, birch, ash or pine. The method involved collection of workplace dust on filters and extraction of 2-MeA with methanol and GC/MS analysis. The method was tested on teak wood du...

2002
Thomas Knoke

Beech (Fagus sylvatica L.) is the most important deciduous tree species in Germany. The wood of beech shows normally a bright colour (white beech) as long as no coloured heartwood has been formed. The facultative heartwood formation is induced when oxygen enters central parts of older trees, where dead or at least less vital parenchyma exist. The coloured heartwood is usually called ‘red heartw...

2011
Primož Oven Maks Merela urša mikac Igor Serša

We demonstrate the use of high-resolution three-dimensional magnetic resonance microscopy (3D MRM) for anatomical studies of woody tissues. Samples of normal and pathological structures in the branches of four tree species were imaged by 3D MRM immediately after removal from the tree, without additional tissue preparation. MRM data sets were displayed in 2D sections and in a 3D volume rendered ...

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