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However, the use of ions as a neutron analogue offers a number of advantages: · In contrast to highly radioactive neutron-irradiated samples, ion-irradiated material is basically inactive
It is sensitive to the annihilation with valence electrons and depends on size and concentration of defects: as higher the number or size of defects as higher the S parameter.
Thereby it is assumed that the sample consists of a certain number of homogeneous layers, which are characterized by a given depth width, mean S parameter, and positron diffusion length L+.
Black points can be considered as defect clusters whereas the lines indicate grain boundaries.
A+ is defined as a negative number, and a larger negative value means a stronger preference of positrons in the concerning material.

A number of works were mentioned by various researchers regarding association of DOE and statistical optimization methods with plasma spraying process.
The required number of spraying passes was carried out to obtain a ceramic layer thickness of 240μm.
A number of microcracks were seen on the surface of the coating.
Each contour curve described an infinite number of combinations of values of two test factors derived from the second-order quadratic equation within the considered limit.
Intl.93 (2016) 29-35 [21] S.Rajakumar, C.Muralidharan, V.Balasubramanian, Statistical analysis to predict grain size and hardness of the weld nugget of friction –stir- welded AA6061-T6 aluminium alloy joints, Int.J.Adv.Manuf.Technol. 57 (2011) 151-165

Such a system may include spheres with different sizes, densities, hardnesses, shape factors, coordination numbers, etc.
It should be noted that taking into account such a large number of factors requires the use of numerical methods and computer simulations to obtain high-quality and reliable approximation solutions.
For the effective implementation of computer and numerical modelling, a number of physical and mechanical characteristics of heterogeneous elements (spheres) were taken into account.
Also, the parameters of the heterogeneous medium were taken into account, in particular, the falling velocity, dynamic viscosity, average coordination number, Prandtl’s coefficient of 0.4, etc.
Xu, Experimental and numerical investigation of Weibullian behavior of grain crushing strength.

., a pore, an inclusion, a abnormal grain or other inhomogeneity inside the specimen), while others fail by an extrinsic flaw (usually located at a corner or a chamfer, i.e. at the surface of the specimen).
Due to the difficulty in performing fractographic examinations for a large number of specimens and in view of investigating several mixtures of two different and overlapping Weibull populations (A + B), the statistical samples that are analyzed in this work are simulated samples consisting of numerical values.
Blind analysis of A + B mixtures Before delivering the mixtures to the statistician in charge of the analysis, each mixture received a code number (see Table 1).
In order to perform a blind analysis, the statistician did not know the origin of the samples, but just the code numbers.
The analyzed statistical samples covered a wide range of mixing proportions: the % of data assigned to one of the populations varied from 97% till 3%, and the total number of data assigned also to one of the populations varied from 400 data values till only 12 data values.

The biological apatite of natural bone tissue, dentin, and enamel contains a considerable number amount of carbonate groups (up to 8 wt.%) [12,13].
The functional groups present in the obtained materials were studied using a Fourier Transform Infra-Red (FTIR) spectroscopy (IRPrestige-21 Spectrophotometer, Shimadzu, Japan) in the range of wave numbers from 400 to 4000cm−1.
The XRD pattern of the obtained material shown in Figure 2 was well-matched to hydroxyapatite with the hexagonal space group P63/m (ICDD - PDF, card number 01-072-1243).
Such influence is the result of adsorption of citrate ions on the surface of the HA particles leading to a retarding of their grain growth.
In total, according to XRD, DLS, and SEM analysis, all the synthesized BMHA powder consisted of agglomerated particles in the micrometer range made up of a huge number of crystallites in the nanometer range which created a porous structure.

It is one of the machines employed to tolerate varying grain particle sizes as desired.
A total number of 36 hammers were employed for the design.
Figures 9 and 10 display the plot of the number of failures changed over time as a function of the months in which they occurred.
The revenue loss was computed using the number of downtime as a function of time, as obtained from the crushing machine.
Effect of number of beaters on the performance of household hammer mill. 

Also from the Table 5 it can be observed that the surface roughness decreases with increased cutting speed which is a usual trend [9].This can be due to the reason that at high cutting speed the heat flow time shortens resulting in the softening of the material and thereby aiding in grain boundary dislocation thus reducing the surface roughness.
Table 12: Typical observations of network performance Parameter Description/ value Network configuration 3 – 40 – 1 Number of hidden layer 1 Number of hidden neurons 40 Transfer function used Logsig(sigmoid) Number of patterns used for training 12 Number of patterns used for testing 2 R value 0.9536 Number of epochs 1000 Learning factor (η) 0.7 Average Error 0.56 % The surface roughness results predicted using the generated neural network is shown in the Table.13.

Procedure of the metal foil LOM technology (N: layer number) process.
This can for example be realised by iterative laser beam melt ablation, i. e. the metal foil is divided after more than one irradiation - the required number of irradiations depends on the used parameters - of the same contour.
Medial slit width and medial cutting angle (material: St2 K50, foil thickness: 100 µm, focus diameter: 50 µm, nozzle diameter: 0,8 mm, ∆z = 0 mm, process gas: 5 bar N2) lineal grain boundaries.
But the required number of layers for realising a defined height can be calculated whereas a shrinkage-factor has to be investigated by experiment before [6].
These two options can differ in the process parameters like the laser parameters and the rate of feed and especially in the number of irradiations.

Introduction In the 1930s, it was first reported internationally that Sb amorphous metal film[1], which is characterized by long range disorder and short range order in the arrangement of atoms in the material, without the existence of crystal boundaries and grains.
According to the analysis, this may be due to the higher suction casting power used in the preparation of 7#(2 mm) and 8#(3 mm) samples, which means that the suction casting temperature of the alloy is higher, and the crystallization kinetics and casting properties of the alloy are largely affected by the number and size of atomic clusters.
At the same time, a large number of veins are densely distributed on the fractures, and the veins develop better and extend longer.
A large number of primary shear zones and secondary shear zones can be found in the macro fracture morphology of this sample.
Although the number and density of veins are reduced compared to the 7#(2 mm) sample, the veins are thicker and develop better, so this sample also has excellent compression performance in the 16 sets of samples in the orthogonal experiment.

For answer this question we need to understand the concept of the Biot number.
The number of Biot plays important role in diffusion problems involving convective effects at the surface of the solid.
Then, in the analysis of a specific problem of mass and thermal diffusion, one should calculate the Biot number and if it is less than 0.1, the smaller error associated with the use of the global capacitance method is obtained.
In this research was considered Biot number of heat transfer and mass transfer 0.09 (Bim = Bic = 0.09).
Formulation independ of the nature of the material to be dried (grain, fruits, vegetables, wood, clay products, etc).