A rapid method for estimating longitudinal growth stresses in logs

1971 ◽  
Vol 5 (1) ◽  
pp. 40-48 ◽  
Author(s):  
J. E. Nicholson
Keyword(s):  
Rapid Method ◽  
Longitudinal Growth ◽  
Growth Stresses

Measurement of surface growth stress in Eucalyptus nitens Maiden by splitting a log along its axis

Holzforschung ◽  
2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Shakti Chauhan ◽  
Kenneth Entwistle
Keyword(s):  
Splitting Method ◽  
Circular Cross Section ◽  
Growth Stress ◽  
Surface Growth ◽  
Longitudinal Growth ◽  
Growth Strain ◽  
Eucalyptus Nitens ◽  
Growth Stresses ◽  
The Relationship ◽  
Longitudinal Growth Strain

Abstract When a log is sawn along the length, an outward bending or deflection of two half rounds arises from the release of growth stresses in the log. The relationship between this outward bending and the peripheral longitudinal growth strain in logs from a 10-year-old Eucalyptus nitens plantation was investigated. In total, 63 trees were felled and two logs (one bottom and an upper log) were cut from each felled tree. A strong association was observed between the measured longitudinal growth strain and the outward bending produced by splitting the log along its axis. A mathematical model was developed that enables calculation of the relationship between the surface axial growth stress and the opening of the split log. This involves calculation of the lateral deflection of a tapered cantilever beam of semi-circular cross-section under a known bending moment. The relationship between the opening of the slit log and the surface axial stress showed good agreement with the measured data on 126 logs. The model equation is effective in predicting the growth stress from the magnitude of the log distortion. This log sawing or splitting method is quick and reliable for assessing the surface growth stresses in small diameter trees. It could have potential in breeding programs for identifying families or clones for low-growth stresses of superior eucalypts for sawn timber production.

scholarly journals Growth Stresses are Highly Controlled by the Amount of G-Layer in Poplar Tension Wood

IAWA Journal ◽  
2008 ◽  
Vol 29 (3) ◽  
pp. 237-246 ◽  
Author(s):  
Chang-Hua Fang ◽  
Bruno Clair ◽  
Joseph Gril ◽  
Sheng-Quan Liu
Keyword(s):  
Tension Wood ◽  
Growth Stress ◽  
Strain Level ◽  
Longitudinal Growth ◽  
Growth Strain ◽  
Growth Stresses ◽  
Tissue Area

To determine how gelatinous fibres and gelatinous layers contribute to the magnitude of longitudinal growth stress in tension wood, anatomical measurements of gelatinous fibres were carried out on poplar tension wood (Populus I4551). It was found that (a) no gelatinous fibres were observed under a growth strain level of 0.06 to 0.08%; (b) almost 100% of the non-conductive tissues contained gelatinous fibres above a growth strain level of 0.15 to 0.19%; and (c) the area of fibres, the area of fibres with gelatinous layers per unit of tissue area, and the thickness of the gelatinous layers predominantly influenced the magnitude of growth stress

scholarly journals Relationships and estimates of longitudinal growth stress in Eucalyptus dunnii at different ages

2008 ◽  
Vol 32 (4) ◽  
pp. 723-729 ◽  
Author(s):  
Paulo Fernando Trugilho ◽  
José Tarcísio da Silva Oliveira
Keyword(s):  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Basic Density ◽  
Longitudinal Direction ◽  
Growth Stress ◽  
Longitudinal Growth ◽  
Growth Stresses ◽  
Dynamic Modulus Of Elasticity ◽  
Eucalyptus Dunnii ◽  
Standing Trees

The objective of this study was to obtain estimates of longitudinal growth stresses in standing trees of the Eucalyptus dunnii Maiden at eight, thirteen, fifteen and nineteen years of age and to determine their relationships with wood characteristics. The longitudinal growth stresses were indirectly measured by the "CIRAD-Forêt" method and estimated from both the dynamic modulus of elasticity and the modulus of elasticity in tension parallel to the grain. The longitudinal residual strain (LRS) and the estimates of the longitudinal growth stresses tended to increase with the age of the material. The LRS correlated positively and significantly with all the growth stresses estimates. The largestes magnitudes were at 13, 15 and 19 years of age. The basic density presented high, positive and significant correlations with the dynamic modulus of elasticity, estimated in the longitudinal direction, for wood saturated and at 12% moisture content, for all the ages assessed. All the growth stresses estimates presented high, positive and significant correlations between themselves.

Texture measurements in Al2O3 using BEKP

1994 ◽  
Vol 52 ◽  
pp. 608-609
Author(s):  
M. D. Vaudin ◽  
J. P. Cline
Keyword(s):  
Neutron Diffraction ◽  
Rapid Method ◽  
Crystallographic Orientation ◽  
Specimen Surface ◽  
X Ray Diffraction ◽  
Anisotropic Crystal ◽  
X Ray ◽  
Verification Method ◽  
Crystal Properties ◽  
Backscattered Electron

The study of preferred crystallographic orientation (texture) in ceramics is assuming greater importance as their anisotropic crystal properties are being used to advantage in an increasing number of applications. The quantification of texture by a reliable and rapid method is required. Analysis of backscattered electron Kikuchi patterns (BEKPs) can be used to provide the crystallographic orientation of as many grains as time and resources allow. The technique is relatively slow, particularly for noncubic materials, but the data are more accurate than any comparable technique when a sufficient number of grains are analyzed. Thus, BEKP is well-suited as a verification method for data obtained in faster ways, such as x-ray or neutron diffraction. We have compared texture data obtained using BEKP, x-ray diffraction and neutron diffraction. Alumina specimens displaying differing levels of axisymmetric (0001) texture normal to the specimen surface were investigated.BEKP patterns were obtained from about a hundred grains selected at random in each specimen.

Some comparative aspects of a longitudinal growth study in normal spanish children and other longitudinal studies

1986 ◽  
Vol 113 (4_Suppl) ◽  
pp. S93-S97 ◽  
Author(s):  
A. FERRANDEZ ◽  
E. MAYAYO ◽  
M. RODRIGUEZ ◽  
J.M. ARNAL ◽  
J. CARO ◽  
...  
Keyword(s):  
Longitudinal Studies ◽  
Environmental Conditions ◽  
Regional Differences ◽  
Longitudinal Growth ◽  
Growth Study ◽  
Growth Studies ◽  
Different Populations ◽  
Catch Up

Abstract The differences existing among some european longitudinal growth studies make it necessary to be cautious in the use of standards constructed on different populations. The improvement of the environmental conditions during the last 20 years is probably the most important cause of the "catch-up" phenomenon of the spanish stature. It is probable that racial characteristics also play a role, even in the same country as can be appreciated on comparing two spanish longitudinal studies based on children originary from different regions. All of wich indicates the need to use own standards in those countries wich, like ours, have lived through a period of intenses changes. Even exploratory studies of regional differences in the same country seem necesary.

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