Imagery Processing System and Its Applications

The existing disproportion between high efficiency of imagery receipt process and low productivity of the ways of their processing makes actual the creation of an Imagery Processing System, which may be used for the estimation of the efficiency of new hardware and mathematical methods of picture processing. The main idea of hardware functional organization is compatibility of special purpose processors and input/output image units with a base computing system in external memory on the disks and tapes level. The base computing system includes three BESM-6 computers with the total external memory field on the disks. The terminal computer (minicomputer M-6000) serving specialized input-output image (phototelegraphic unit NEVA , System P-1700 photomation MARK-11, direct input channel, etc.) is connected with the base computing system. The software of Imagery Processing System includes system programs and functional processing programs. The system programs serve general structure of the system, providing the connection of a user with this system, the image input-output operations, the general control of image processing, the error search and logging, dynamic allocation memory, the maintenance of interface demands of the system, etc. The functional processing programs of the system are based on modular design. The program modules are arranged in the application program pack. The main part of the programs is related to the program pack of preprocessing, which is a preprocessor for all the other application program packs, since it has the program modules connected with the presentation of pictorial information and storage of it in the system (image registration, reformatting, enhancement, filtering, edge detection, geometric rectification, etc). Specialists of nature control institutes of the Siberian Branch of the USSR Academy of Sciences, who are the main users of Imagery Processing System, should play the leading role in the creation of special program packs. The main topics of application research are connected with the study of geological structure of the earth, mineral exploration, timber inventories, fire control, the mapping of agricultural regions of Siberia, environmental impact analysis, crop identification, environmental protection, etc. The theory of inverse problems of mathematical physics is important for remote sensing method. Mathematical statements of-inverse problems a rise in interpretation of multispectral scanner data. They are mathematical methods of inverse problems, that to all appearance, will come up to take place of widespread correlation method in imagery interpretation. The inverse problems, in particular, the inverse optic problems, are one of the main topics in research work of the Computing Center

Properties of Zirconia after Plasma Treatment

The influence of high-frequency plasma treatment on the properties of zirconia powder is shown in the work. The powder was produced by a plasma-chemical method. The powders had a foamy form with the size of agglomerates of 5-10 [mu]m and crystallites of 20-50 nm. The powders were treated by the pulse plasma unit with dielectric barrier discharge generator. It was shown that the plasma processing changes the acidity of water-powder suspensions from 8.1 to 4.3 pH, which signifies the powders' wettability improvement. It was revealed that more intensive mixing using ultrasound influences the acidity level, reducing it in comparison with mixing by paddle-type agitator. It was shown that these changes of surface properties have relaxation by 4% per day and extrapolation of this dependence shows that the powder will have initial properties after 400 hours storage at room conditions

Simulation of fracture of the bone implant with the porous structure

Different approaches to bone defects reconstruction with the use of ceramic materials have been developed recently. Ceramics are identical with bone matrix, provide biomedical compatibility with bone tissue and possess high strength. But with an overall high strength ceramic implants destruct in dynamic mode. The paper presents a study of the effect of the porosity gradient on the destruction of the bone implants under dynamic loading. It is shown that the fracture behavior of the bone implants is changed with increasing levels of the gradient of porosity

Damage formation, fatigue behavior and strength properties of ZrO[2]-based ceramics

It is suggested that a non-destructive testing technique using a three-dimensional X-raytomography be applied to detecting internal structural defects and monitoring damage formation in a ceramic composite structure subjected to a bending load. Three-point bending tests are used to investigate the fatigue behavior and mechanical and physical properties of medical-grade ZrO[2]-based ceramics. The bending strength and flexural modulus are derived under static conditions at a loading rate of 2 mm/min. The fatigue strength and fatigue limit under dynamic loading are investigated at a frequency of 10 Hz in three stress ranges: 0.91-0.98, 0.8-0.83, and 0.73-0.77 MPa of the static bending strength. The average values of the bending strength and flexural modulus of sintered specimens are 43 MPa and 22 GPa, respectively. The mechanical propertiesof the ceramics are found to be similar to those of bone tissues. The testing results lead us to conclude that the fatigue limit obtained from 10{5} stress cycles is in the range 33-34 MPa, i.e. it accounts for about 75% of the static bending strength for the test material

Damage formation, fatigue behavior and strength properties of ZrO[2]-based ceramics

It is suggested that a non-destructive testing technique using a three-dimensional X-raytomography be applied to detecting internal structural defects and monitoring damage formation in a ceramic composite structure subjected to a bending load. Three-point bending tests are used to investigate the fatigue behavior and mechanical and physical properties of medical-grade ZrO[2]-based ceramics. The bending strength and flexural modulus are derived under static conditions at a loading rate of 2 mm/min. The fatigue strength and fatigue limit under dynamic loading are investigated at a frequency of 10 Hz in three stress ranges: 0.91-0.98, 0.8-0.83, and 0.73-0.77 MPa of the static bending strength. The average values of the bending strength and flexural modulus of sintered specimens are 43 MPa and 22 GPa, respectively. The mechanical propertiesof the ceramics are found to be similar to those of bone tissues. The testing results lead us to conclude that the fatigue limit obtained from 10{5} stress cycles is in the range 33-34 MPa, i.e. it accounts for about 75% of the static bending strength for the test material

Numerical simulation of mechanical behaviour and prediction of effective properties of metal matrix composites with consideration for structural evolution under shock wave loading

Mechanical behaviour of stochastic metal-ceramic composite materials under shock wave loading was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites whose structure consisted of a metal matrix and randomly distributed ceramic inclusions was simulated. The results of numerical simulation were used for numerical evaluation of effective elastic and strength properties of metal-ceramic materials with different values of volume concentration of ceramic inclusions. The values of the effective mechanical characteristics of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure of composites was determined. It is shown that the dependence of the values of the effective elastic moduli on the volume concentration of ceramic inclusions is nonlinear and monotonically increasing. The values of the effective elastic limits increase with increasing concentration of the inclusions, however, for the considered composites, this dependence is not monotonic

The Study on Thermal Expansion of Ceramic Composites with Addition of ZrW[2]O]8]

The studies on structure, phase composition and thermal properties of (Al[2]O[3] - 20 wt% ZrO[2]) - ZrW[2]O[8] ceramic composites obtained using nanosized, initial powders were conducted. Homogeneously distributed white particles on the polished surface of composites were observed. Phase composition of the composites was represented with corundum, monoclinic ZrO[2] and two modifications of ZrW[2]O[8] (tetragonal and cubic). Linear thermal expansion coefficient values of the composites were determined. The difference in experimental and calculated coefficient of thermal expansion values for composites obtained may be attributed to phase transformations, features of the structure, internal stresses due to thermal expansion mismatch, which contribute significantly to thermal expansion of the ceramic composites

The impurity influence on the formation of oxide layers on TiAL surface

Using ab initio approach the segregation of 4d impurities to low index TiAl surfaces was studied. The site preference for all considered impurities was determined. We demonstrate that Y, Zr, Nb и Mo prefer to occupy the Ti-sublattice whereas other elements are located mainly on the Al-sublattice in case of their low concentration. The influence of impurities on oxygen adsorption on the stoichiometric γ-TiAl(100) surface is investigated. It is shown that the 4d impurities substituting for Ti result in decrease of oxygen adsorption energy whereas it increases if transition metal impurities occupy the Al-sublattice. The effect of some elements of V and VI groups on the adhesion at interfaces such as TiAl(001)Al/TiO2(001), TiAl(001)Ti/TiO2(001), TiAl(100)/TiO2(001), TiAl(110)Al/TiO2(100)O and TiAl(110)Ti/TiO2(100)O in dependence on their location in interfacial layers was also studied. Finally, we demonstrate that the 4d alloying elements with number of electrons from 2 to 5 lead to decrease of the relative stability of Al2O3 to TiO2 and to increase of the formation energy of O vacancy in TiO2. The latter is beneficial to the oxidation resistance of TiAl alloys

Investigation of failure mechanism of Al2O3 specimens subjected to three-point bending test

Experimental loading and FEM simulation-based approach at macroscale are utilized to investigate the failure mechanisms of Al2O3 ceramics. Experimental characterization of the microstructure is carried out using SEM. Recently the mesoscale models of a representative volume of porous alumina ceramics were built on the basis of grain and pore distribution patterns and subjected to uniaxial loading in order to determine effective mechanical characteristics which are utilized for macroscopic simulation in this work. Pre-fracture behavior of specimens undergoes the Drucker-Prager model with non-associated plastic flow rule. Experimental and numerical simulation fracture patterns show that material exhibits predominantly mode I, sometimes passing to mixed mode I+II of crack propagation. Comparison of experimental data and numerical simulation data gives a good agreement

Preferred orientation evolution of olivine grains as an indicator of change in the deformation mechanism

The paper presents the results of investigations of deformed natural polycrystalline olivine. The relationship of the structure of polycrystalline olivine grains to three modal size distributions has been revealed. Grains of different size were observed to be strained at threshold temperatures of 950, 775, and 650°C. It has been demonstrated that the microstructure develops as the dislocation mechanism changes from diffusion creep to grain boundary sliding. The changes in deformation mechanisms promote the change in the preferred crystallographic orientations of olivine from type A to type D and then to type B. The relation of the transitions between different types of orientations to the conditions of deformation in the lower layers of the lithosphere at the plate boundaries is discussed