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This study developed new algorithms to simulate the grain pattern and orientation of radiata pine boards based on the geometrical and growth features of radiata pine trees.
Wood grain has been an interesting topic for sawmills, as severe grain deviation decreases wood strength [4], and is the most serious single defect resulting in drying deformation associated with variation of moisture content [5].
Sawmills have been looking for feasible log breakdown strategies to maximize timber value [6], and it is desirable to know the grain pattern and orientation prior to log cutting.
Conclusion and Discussion Severe grain deviation is one of the key factors significantly affecting timber quality.
Adjusting factors should be applied when a tree has severe spiral grain, which will be reported in other paper.

A value for the average grain size along the whole cross section (diameter 250 mm) of 700 µm for the billet without grain refinement and 250 µm for the billet with grain refinement could be measured.
In this case the grain size distribution was inhomogeneous and the grain sizes ranged between 8 and 200 µm.
In theory recrystallization strongly depends on the forming temperature, the forming velocity, the number of defects and the microstructure [11].
The grain refined billets showed both finer grains and Mg2Si-precipitations.
Owing to the grain refinement 2.8 times smaller grain sizes and a homogeneous grain size distribution could be reached.

The (sub)grain size decreases both with decreasing temperature and with increasing number of passes.
This table also clearly shows that the “processing stress” (σProc=Fmax/S, being S the ECAP section equal to 1 cm2) increases with both decreasing temperature and increasing number of passes.
It is shown that at a processing temperature of 300°C (sub)grains decrease in size with number of passes similarly to other severe plastic deformation methods operating at low-intermediate temperature.
Applied force (Fmax, kN), (sub)grain size (d, nm) and hardness Vickers (HV) for samples ECAPed at various temperatures (T, ºC) and number of passes (N).
A proof of this relation is given in Fig. 4a for ECAP processing where the processing stress rationalizes the obtained (sub)grain data into a single line, irrespective of the number of passes and processing temperature.

The grain size is strongly related to the number of nuclei.
Different pulse number of laser.
From the last section, on the average grain size, the effect of coverage rate is similar to that of its corresponding pulse number.
Table.3 shows the average grain sizes of different pulse numbers and laser intensities.
This could increase the nucleus number, which leads to the smaller grain size.

Diffusion Controlled Grain Triple Junctions Wetting in Metals B.S.
The number of the filled TJs was determined and shared on their total quantity on the observable area.
Area number one where the melt fills the GBs and TJs both.
And area at number two where the melt fills only TJs of grains.
Randle: The Measurement of Grain Boundary Geometry.

Such a behavior is conditioned by a hexagonal-close packed lattice of magnesium with an axial ratio c/a=1.624, being close to the ideal value and resulting in the lack of adequate number of slip systems to accommodate overall strain.
Total number of cycles was 18 with corresponding true strain of a billet e=10.2 (i.e., 4.2 at 400, 3.0 at 300 and 3.0 at 2000C).
Namely, the areas of the fine equiaxed grains acquired the volume fraction of ~75-80% and so, the fine grains became the main structural component.
One can, therefore, conclude that the main structural changes on the second step of MIF were related to further decrease in the fraction of the coarse fragments of original grains, as well as to the refinement of more coarse grains that were present in fine-grained matrix.
Final MIF step at 200oC results, in turn, in grain refinement down to the nearly submicron grain size level, promoting, however, rather non-uniform on both the meso- and microscopic levels the alloy ultrafine grain structure.

The deformation behaviour of Ni having different grain sizes and various grain boundary states are also considered.
The grain size and structural components were determined from the TEM images by counting at least 100 grain diameters.
The grains contain walls and cells (Fig.1b).
Groups of grains are displaced one relative to the other along grain boundaries.
Nonequilibrium grain boundaries with a high density of defects are a strong barrier to dislocation movement; and both the large number of grain boundaries and subgrains in UFG material after SPD provided for rapid deformation hardening.

It is an answer to the question of how far the particle will be from an arbitrary starting point after some very large number of random jumps, given the number of jumps per second and the mean jump distance.
Over the period of hours or days, the number of jumps becomes astronomical.
In this diffusion model, the computer specimen is decomposed into certain number of cells.
A cell is characterized by its label (0-n), its position (X, Y ) and the number of atoms in it A cell representing the bulk of a grain Cells representing grain boundaries Examples A random computer specimen is generated and shown in Fig. 2a.
There are a large number of diffusion coefficients available in the software database.

Grain boundary sliding.
Shear and normal traction acting on a plane boundary with a normal vector can be calculated as follows: (2-1) (2-2) The superscript indicates the number of assumed boundary plane.
It is worth mentioning that assuming a higher number of slide directions than 12 had no significant change in the results, therefore, only 12 slide directions were enough in the present modeling.
Grain interior plasticity.
The numbers of grains P with various diameters in NC materials can usually be well represented by a log-normal distribution function: (39) where d is the grain diameter and and are constant parameters describing the median and shape parameters of the distribution, respectively [26].

As the K2O was added to 0.5 mol%, the number and the size of abnormal grains were increased by much.
It can be seen that the number of abnormal grains increases with K2O addition.
Therefore, the number of grains that show abnormal growth is increased.
An increase in the sintering temperature also lowers the critical driving force, resulting in an increase in the number of abnormal grains.
Further reduction in the critical driving force, the number of abnormal grains increases more with increasing sintering temperature.