Saving the Forest: The Serialization of Wood Specimen Collections

2019 ◽  
Vol 94 (3) ◽  
pp. 228-238
Author(s):  
Vance Byrd
Keyword(s):  
Wood Specimen

J-integral evaluation in cracked wood specimen using the mark tracking method

2012 ◽  
Vol 47 (2) ◽  
pp. 257-267 ◽  
Author(s):  
Octavian Pop ◽  
Frédéric Dubois ◽  
Joseph Absi
Keyword(s):  
Wood Specimen ◽  
J Integral ◽  
Tracking Method ◽  
Integral Evaluation

scholarly journals A coupling model based on grey relational analysis and stepwise discriminant analysis for wood defect area identification by stress wave

BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1171-1186
Author(s):  
Xin Li ◽  
Wei Qian ◽  
Liting Cheng ◽  
Lihong Chang
Keyword(s):  
Wave Propagation ◽  
Stress Wave ◽  
Propagation Velocity ◽  
Wood Specimen ◽  
Coupling Model ◽  
Stress Wave Propagation ◽  
Sectional Area ◽  
Wave Propagation Velocity ◽  
Cross Sectional ◽  
Stress Wave Propagation Velocity

Based on the experimental idea of reverse simulation, a quantitative area of hole was excavated at the sectional center of a wood specimen. The excavation area was 1/32S, 1/16S, 1/8S, 1/4S, and 1/2S (where S represents cross-sectional area of the complete specimen) and stress wave nondestructive testing of six sensors was performed. The stress wave propagation paths were statistically summarized to obtain the stress wave propagation velocity (Va) for two adjacent sensors, the stress wave propagation velocity (Vb) for two separated sensors, and the stress wave propagation velocity (Vc) for two opposite sensors. Furthermore, by analyzing the advantages and disadvantages of grey relation and stepwise discriminant model when both of them were used alone, a coupling model generated from them was established to dispose the test data. The attenuation ratios Ψa, Ψb, and Ψc of stress wave under three propagation paths and their relation ratios Va/Vb, Vb/Vc, and Va/Vc, a total of six groups of measured data, were selected as discriminant factors for the hole area grade of the wood specimen. The verification results showed that the discriminant accuracy of the coupling model was 100%, and it was concluded that the attenuation ratio (Ψb) of the stress wave propagation velocity for two separated sensors had the strongest discriminant ability against cross-sectional area of the specimen.

Assessment of the Fluctuations in the Microstructural Parameters of Cellulose in Wood in an Inhomogeneous Temperature Field

2018 ◽  
Vol 45 (6) ◽  
pp. 275-278
Author(s):  
N.N. Matveev ◽  
N.S. Kamalova ◽  
N.Yu. Evsikova ◽  
A.S. Chernykh
Keyword(s):  
Temperature Field ◽  
Crystallite Size ◽  
Wood Specimen ◽  
Average Crystallite Size ◽  
Potential Difference ◽  
Microstructural Parameters ◽  
Inhomogeneous Temperature ◽  
Inhomogeneous Temperature Field ◽  
Homogeneous Temperature

The possibility of assessing the average crystallite size of cellulose in wood by formalised modelling from the magnitude of the potential difference arising in the wood specimen owing to polarisation in a non-homogeneous temperature field is considered.

Effect of Anisotropy on Shear Wave Velocity in Wood

2012 ◽  
Vol 535-537 ◽  
pp. 1923-1926
Author(s):  
Jian Ping Zhou ◽  
Jin Xia Liu ◽  
Wen Yang Gao ◽  
Zhi Wen Cui ◽  
Wei Guo Lv ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Radial Direction ◽  
Rotation Angle ◽  
Wood Specimen ◽  
Shear Waves ◽  
Circular Ring ◽  
The Relationship ◽  
Intrinsic Birefringence

The velocities of shear waves propagating along radial direction of birch and elmwood specimens are measured in order to study the effect of anisotropy on shear wave velocity. The relationship between the shear wave velocity and the oscillation direction is examined by rotating an ultrasonic sensor. The results indicate that the effect of anisotropy on shear wave velocity in birch and elmwood specimens is similar to Japanese magnolia specimen. When the oscillation direction of the shear wave corresponds to the certain anisotropic direction of the wood specimen, the shear wave velocity decreases sharply and the relationship between shear wave velocity and rotation angle tends to become discontinuous. The intrinsic birefringence due to the anisotropy of birch and elmwood woods is observed. Their texture anisotropies are strong. In an isotropic nylon, on the contrary, the value of shear wave velocity was similar to a circular ring. This investigation is significant meanings in architectural and civil engineering field.

The Influence of Wood Specimen Surface Coating on Moisture Movement during Drying

Holzforschung ◽  
2002 ◽  
Vol 56 (5) ◽  
pp. 541-546 ◽  
Author(s):  
R. Baronas ◽  
F. Ivanauskas
Keyword(s):  
Surface Coating ◽  
Transverse Section ◽  
Wood Specimen ◽  
Two Dimensional ◽  
Drying Process ◽  
Dimensional Model ◽  
Wood Drying ◽  
Moisture Movement ◽  
One Dimensional ◽  
The One

Summary A model of wood drying under isothermal conditions taking into consideration coating of the surface of a specimen is presented in this paper in a two-dimensional formulation. The influence of the surface coating degree as well as geometrical shape of a wood specimen on the dynamics of drying is investigated. Exponentials, describing the dependence of the halfdrying time on the degree of coating of the edges, as well as on the ratio of the width to the thickness of the transverse section of specimens from the northern red oak (Quercus rubra), are presented for drying from above the fiber saturation point. This paper describes the conditions of usage of the two-dimensional moisture transfer model in contrast to the one-dimensional model for accurate prediction of the drying process taking into consideration the coating of edges of specimens having a rectangular transverse section. A measure of reliability of the one-dimensional model to predict the wood drying process of sawn boards is introduced in this paper.

scholarly journals The Influence of Specimen Size and Distance to a Surface on Resistive Moisture Content Measurements in Wood

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Maria Fredriksson ◽  
Johan Claesson ◽  
Lars Wadsö
Keyword(s):  
Boundary Condition ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Wood Specimen ◽  
Electrical Potential ◽  
Electrical Current ◽  
Specimen Size ◽  
Equivalent Radius ◽  
Measured Moisture Content ◽  
Wood Surfaces

The moisture content of wood is commonly determined by measuring the electrical resistance between two electrodes inserted in the wood. However, problems using this method close to wood surfaces were reported in a previous study. In the present study, the effect of the distance to a surface and the specimen size on the measured electrical resistance was studied analytically as follows. The two electrodes create an electrical potential in the wood specimen. The boundary condition for the electrical potential is that the electrical current across all specimen surfaces is zero, which is achieved by using a suitable array of mirror sources. The analytical solution for the electrical potential was used to analyse the influence of the distance from the electrodes to the specimen surface as well as the size of the specimen. In addition, the error in moisture content was evaluated. The effect of the distance to a surface and the specimen size depended on the equivalent radius of the electrodes; if large electrodes are used in small specimens or close to surfaces, there is a risk that a higher resistance is measured which results in slightly lower measured moisture content than the actual moisture content of the specimen.

scholarly journals Influence of the Wood Specimen Position on Calculus of the Bending Modulus of Elasticity

2013 ◽  
Vol 3 (3) ◽  
pp. 41-46 ◽  
Author(s):  
Icimoto Felipe Hideyoshi ◽  
Ferro Fabiane Salles ◽  
Almeida Diego Henrique de ◽  
Christoforo André Luis ◽  
Lahr Francisco Antonio Rocco
Keyword(s):  
Modulus Of Elasticity ◽  
Wood Specimen ◽  
Bending Modulus

Properties of piezoelectric voltage considering the microscopic structure of wood cell walls

Holzforschung ◽  
2007 ◽  
Vol 61 (1) ◽  
pp. 95-100 ◽  
Author(s):  
Takahisa Nakai ◽  
Hiroyuki Yamamoto
Keyword(s):  
Shear Strain ◽  
Wood Specimen ◽  
Microfibril Angle ◽  
Middle Layer ◽  
Fiber Axis ◽  
Crystalline Cellulose ◽  
Grain Angle ◽  
Average Shear ◽  
The Relationship ◽  
Piezoelectric Voltage

Abstract The combined effects of the grain-angle (θ) and the microfibril angle (MFA) on the piezoelectric voltage (P) are discussed for a wood specimen subjected to unidirectional stress. The fiber axis of the specimen investigated was not parallel to the loading direction. A theoretical discussion is provided concerning fundamental elastic equations that predict the elastic strain field in the crystalline cellulose microfibril (CMF). It was assumed that an ideal wood specimen could be represented by a multi-tracheid model consisting mainly of the middle layer of the secondary wall. Experimental results revealed that plots of the piezoelectric voltage (P) versus the grain angle (θ) show concave curves with a maximum at θ=45°, regardless of MFA in the specimen. A similar tendency was obtained for the relationship predicted between the average shear strain along the CMF and θ. The results indicate that generation of a shear strain in the CMF positively contributes to the piezoelectric effect in wood.

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