Search results

The grain-size distribution of the sieved sand ranged from 1mm to 1.25 mm.
The DLVO theory [17,28] was used to calculate the interaction energies between SP and grain sand system [19].
Particle attachment was only possible on regions of the grain surface where the hydrodynamic drag forces acting on SP adjacent to grain surfaces was less than the adhesive forces and the gravity forces that resist release.
NVp is the number of injected pore volumes.
This behavior can be explained by the fact that the attractive forces between the particles and the sand grain surface were dominant.

In recent years, the target of local feature extraction and recognition technology is a hot research topic in digital image processing and computer vision field.In target recognition, pest undetected phenomenon often happens due to occlusion, once the conditions are favorable, pests quickly multiply and spread, causing great harm to the stored product.we established a common stored product pests image database, proposed feature extraction and matching algorithms, based on the combination of improved SURF and multi-resolution histogram.Pests specified in the database for target identification, especially when the pest is partially obscured, or the shape and size changes,by finding matching number of feature points the description of the target for accurate identification .This method is efficient, time-saving,provides an important scientific basis for the entry-exit inspection and quarantine in rapid identification of stored product pests.It is more conducive to the subsequent classification
The pest local extracted feature matrix as multi-resolution histogram matching algorithm input, based on the principle of multi-resolution histogram: given two images, one image local feature point number as m, another as n, dimension of local feature points is d, the feature is defined as two images for: ， Among them: ,,,,.
Rapid machine vision method for the detection of insects and other particulate biocontaminants of bulk grain in transit[J].
Image of pests in stored grain machine vision detection method of [J]. and fuzzy system based on computer applications, 2005,22 (8): 24~25 [6] Zhang Hongmei, Fan Yanfeng, Tian Geng.

To be specific, we found that a number of areas in the subject of diffusion require this type of special pedagogical assistance.
Visualization of diffusion fields and demonstration of their evolution is a skill much appreciated by students, who are impressed by their being able to display details of the dynamics of complex fields, rather than just develop its equation and extract a few numbers to characterize it.
Modules were prepared to cover the following topics: 1) Introduction; 2) Phase transitions: unary and binary systems; 3) Diffusion in infinite systems; 4) Solutions to the diffusion equation; 5) Diffusion induced phase change; 6) Diffusion Mechanisms; 7) Diffusional growth and dissolution; 8) Vacancy-Assisted Diffusion;5 9) Diffusion/reaction; 10) Substitutional Diffusion; 11) Interfaces; 12) Grain Boundaries; 13a) Grain mobilities-2d Crystal Growth; 13b) Grain mobilities-3d Crystal Growth; 14) Boundaries and Interfaces; 15) Solid-State Interfaces; 16) Solid-State Nucleation and Precipitation; 17) Solid-Liquid Interfaces; 18) Chemical Segregation at Solid-Solid Interfaces; 19) Stability of Solid-Liquid Interfaces; 21) Casting; 22) Nucleation Catalysis; 23) and 24) Polyphase transformations-Eutectic Microstructures; 25) Population Dynamics: Capillarity and Phase Coarsening.
A number of specific areas in the subject of kinetics require this type of support and emphasis.
Other sources found useful for completing the lecture modules derive from documents shared with other scientists: 1) Professor Dorel Munteanu (Baton Rouge University, LA) provided vertex model-topological grain growth movies (isotropic.gif, migr rot.gif);2)Dr.

The trapping air bubbles decreases in size and increase in number and it has the ability to coagulate the foam with metal ions.
The decrease in dielectric constant can be explained that solid is assumed as composed of good conducting grains separated by poor conducting grains [30-31].
The resistance of grain boundary is high.
So the electron crash at the grain boundaries and cause polarization.
Fig. 7B shows the presence of more number of rectangular shape particles of size ranges from 7 nm to 21 nm.

Materials, having low density or high porosity, high specific surface area and fine grain structure, are needed for catalysts, sensors, filtration membranes, composites, etc.
The average grain size is about 10 nm and the density remains very low (< 0.1g/cm3).
At 1200 – 1250 °C, transformation into �-alumina occurred what led to a microstructure with a 200-300 nm grain size, Fig. 4. 50 nm 200 nm200 nm200 nm Fig. 3.
However, the transformation of each corundum grain into spinel produces aggregated spinel crystallites with a size around 100 nm.
Samples mass gain as a function of number of impregnation cycles in uranyl nitrate solution with concentration 579 g/l. 0 2 4 6 8 10 12 14 16 18 1 2 3 4 5 6 7 Weight gain, g Number of cycles U3O8 1 300 % wt 3-Al2O3 0,83 g/cm3 0 1 2 3 4 5 6 7 8 9 10 11 0 100 200 300 400 500 600 700 800 Weight gain, % Number of cycles U3O8 1 800 % wt SiO2·Al2O3 ~ 0,3-0,4 g/cm3 3.

A number of experimental investigations have been carried out to study the change characteristics of the specific energy [1, 2].
The saw blade was modeled as a rigid body by using wall elements, and the different diamond grain shapes were randomly generated.
As is shown in Fig.2, the increase in cutting depth causes the number of cracks to increase.
However, the simulation results are greater than experimental results for both forces with increasing cutting depth because (1) sawing forces were caused by the formation and propagation of the cracks in the form of bond breakage between particles, the bond strengths between and internal irregular particles were set equal in numerical model while unequal bond strengths were used in actual materials; (2) there exit differences in mechanical properties inevitably between numerical and experimental models for both granites, including the compressive strength, the bending strength and so on; (3) the diamond grain's movement were regarded as plane motion due to 2-D simulation in this study, the extrusion to particles both sides of diamond grain were ignored in actual 3-D problems.
Since the value of the vf influences the number and formation time of the cracks, the decrease in vf cause the experiment results to agree well with the numerical results at the same ap, however, the difference between the experimental and numerical results increase with the feed rate vf because (1) there exit differences in particle shapes between sample and actual particles despite irregular shape particles were modeled, which influences the contacts between the particles and the saw blade; (2) the simulative diamond grains distributed in the saw blade were regarded as rigid body which have no wear in DEM sawing process while the real diamond grains were in state of gradual wear in experiment.

The modifications are essentially within the shear bands where the a+b grains deformed extensively.
The b grains became elongated and their thickness could reduce to sizes as low as 20 nm [4].
Analysis of several metals has revealed the importance of the level of energy density and number of pulses imparted to the material for modifying the surface microstructure.
The deformation twins were only observed in grains having their <111> axis perpendicular to the surface (i.e. also along the electron beam) [29].
This is again illustrated in Fig. 5 (right) for a sample of 316 L steel for which a <111> fiber texture has formed after sufficient number of LEHCPEB pulses.

Fatigue Life and Fracture Morphology Figure 3 shows the relationship between crack length and cycle number.
This is the result of high-density dislocation on the surface, and the high-density dislocation line gradually forms dislocation pinning and dislocation entanglements, then the dislocation wall evolves into sub-grain boundary, which results in grain refinement.
A large number of dimples can be seen in both of them, showing obvious ductile fracture characteristics.
It's caused by the grain refinement after LSP, which makes the stress more uniform and reduces the stress concentration, the microscopic cavity grows uniformly in all directions.
The total number of mesh elements is 144963, as shown in Figure 6.

For all these types of musical instruments, it is necessary to produce a large number of different types of keys, which together with other parts of the instrument ensure its correct sound when playing.
For this reason and because a large number of keys are required to assemble a musical instrument, investment casting technology is used [3, 4, 5, 6, 7, 8].
The number of these defects and their type then greatly influence the possibility of their removal and fundamentally affect the service life of the manufactured part.
Higher brittleness is associated with the position of lead-based particles mainly distributed along the grain boundaries of the matrix, see Fig. 5.
- In addition, the Pb particles of this alloy are better distributed in the volume of the casting in similarly small spherical formations mainly along the grain boundaries of the matrix, see figures 3 and 5

According to [4] the pre-exponential velocity for an interface between a spherulite and the supercooled amorphous matrix can be described as         ∆+ − = f u Gbab Tk b TkJbN σσ 2 B B 0 p l & nx (3) where 0N is the number of initial stems, next to be involved in the first stem deposition process, n the unit vector of the respective interface segment, and ul the monomer length.
J amounts to       = h Tk n J z Bς (4) where ς is a constant for the molecular friction experienced by the chain as it is reeled onto the interface, zn the number of molecular repeat units in the chain, and h the Planck constant.
If a moving boundary segment sweeps a cell, the grain volume thus changes by 3mλ rather than b 3.
For obtaining a scale-independent grain boundary velocity, the grid frequency must be chosen in a way to ensure that the attempted switch of a cell of length λm occurs with a frequency much below the atomic attack frequency which attempts to switch a cell of length b.
Journal Title and Volume Number (to be inserted by the publisher) 5 Fig. 1 shows as a calculation example the Cahn-Hagel diagram together with 2 sketches of the microstructure for a simulation at 360K.