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In the paper, we discuss an approach to the development of methods for managing seismotectonic deformation processes in a multiscale block-structured Earth’s Crust from the viewpoint of the concept of physical mesomechanics. To date, there are no convincing results of many year researches in the fields of earthquake prediction and prevention of the dangerous man-caused and tectonic earthquakes. Therefore, in recent decades, there has been an increasingly active search for new ways to solve the problem of seismic safety. The aim of our research team’s activity is to provide a scientific rationale for a multidisciplinary approach to reduce the excess level of shear stresses in the fault zones to a safe background level by “spending” it on mechanical destruction and thermal processes in rocks during aseismic and coseismic slip. The authors summarize the main results of modeling of geological and geophysical processes in the field of preparation of different scale seismogenic events, as well as the results of complex man-made impacts on segments of seismically active faults. The data obtained on segments of different scale faults within the Baikal rift zone and Mongolia confirm the possibility of implementing such an approach. For the practical implementation of such a project at highly stressed fault zones, it is necessary to carry out vertical, oblique and horizontal multilateral drilling with an injection of fluids of different compositions in combination with vibro-pulse stimulations to achieve safe relaxation of shear stresses. [ABSTRACT FROM AUTHOR]

An important component of modern biomedicine is the development and use of hybrid bioactive nanomaterials with a hierarchical structure. The unique physical and chemical properties of low-dimensional aluminum oxyhydroxide nanomaterials with an irregular structure make it a promising base for the creation of hierarchical nanoagents with biological activity. Therefore, it is of fundamental and applied importance to study the interaction of organic molecules and ions of a biological medium with irregular fragments of folded (crumpled) two-dimensional aluminum oxyhydroxide nanostructures. This paper uses all-atom molecular dynamics models to investigate numerically the interaction of AlOOH fragments with a biomolecule and the formation of a hybrid nanocomplex in the zone of a nanosheet defect. The free energy of hybrid complex formation in the region with an irregular structure of AlOOH is estimated using steered molecular dynamics. It is shown by the example of a defect observed as nanosheet folding with a kink that the irregular regions of low-dimensional nanomaterial can play a major role in the adsorption of ions of a biological medium and the formation of hierarchical organo-inorganic complexes with bioactive molecules. [ABSTRACT FROM AUTHOR]

The use of low-dimensional nanomaterials as a bioactive nanoagent or as a component of a hierarchical bioactive nanoparticle has a rapidly expanding range of therapeutic and diagnostic applications. An important role in these applications belongs to low-dimensional nanostructures of metal hydroxides and oxyhydroxides owing to the unique combination of their structural, chemical, and physical properties. Two-dimensional hydroxides consisting of biodegradable components such as iron compounds are of special interest for biomedical applications. An important aspect in the determination of nanomaterial behavior within biological microenvironment is the interaction of the material surface with biomolecules and extracellular ions. Aiming to understand the molecular-scale features of two-dimensional Fe(II) hydroxide interaction with biological microenvironment, we performed a series of steered molecular dynamics simulations and estimated the adsorption free energies of three typical biomolecules and anions. The results were compared with the previously obtained data for gamma-aluminum oxyhydroxide and layered double hydroxide nanosheets. [ABSTRACT FROM AUTHOR]

Current geophysical experience shows that conventional measures proposed by the world scientific community to withstand seismic hazard, including various types of seismic zoning and earthquake prognosis, as well as costly earthquake-proof building, prove to be insufficient as they do not allow to avoid the destructive consequences of very strong earthquakes. Therefore, in recent decades, many geophysicists proposed new approaches to ensuring seismic safety. The present paper briefly discusses the results of geophysical studies, which are based on carrying out complex man-caused impacts on segments of seismically active fault zones. We discuss the prospects of formulation of a multidisciplinary approach to seismically safe reduce of the excess elastic strain energy in fault zones to a safe background level for hundreds of years. Potential realizability of the proposed approach is confirmed by the experience of small-scale tests in the fault segments of the Baikal rift zone. The key issues that inevitably arise during complex large-scale testing are considered by the example of the Arshan segment of the Tunkinsky riftogenic fault. [ABSTRACT FROM AUTHOR]

The paper presents the development of recently proposed kinetic model of dynamic mechanical behavior of brittle solids. The model uses the ideas of kinetic theory of strength to describe the inelastic deformation and fracture. The main feature of the modified dynamic model is the introduction of two relaxation times, which determine the patterns of inelastic deformation under dynamic loading, including the dependences of the values of the cohesion and strain hardening coefficient on the strain rate. These relaxation times have the meaning of a generation time of damage of the smallest ranks and a characteristic time of formation of a system of local damage and cracks of the greatest rank. The advantage of a developed dynamic model is the possibility of its implementation within different conventional models of inelasticity of brittle solids. In the paper we implemented the kinetic model within the classical “quasi-static” Nikolaevsky’s plasticity model (non-associated plastic flow rule with the plasticity criterion in the form of Mises– Schleicher). We verified the model and determined its parameters by the example of high-strength concrete. The developed dynamic model can be implemented within the framework of various Lagrangian numerical methods (including finite and discrete element methods) using an explicit integration scheme. [ABSTRACT FROM AUTHOR]

In the paper we briefly outline the experience in forecasting catastrophic earthquakes and the general problems in ensuring seismic safety. The purpose of our long-term research is the development and improvement of the methods of man-caused impacts on large-scale fault segments to safely reduce the negative effect of seismodynamic failure. Various laboratory and large-scale field experiments were carried out in the segments of tectonic faults in Baikal rift zone and in main cracks in block-structured ice cove of Lake Baikal using the developed measuring systems and special software for identification and treatment of deformation response of faulty segments to man-caused impacts. The results of the study let us to ground the necessity of development of servo-controlled technologies, which are able to provide changing the shear resistance and deformation regime of fault zone segments by applying vibrational and pulse triggering impacts. We suppose that the use of triggering impacts in highly stressed segments of active faults will promote transferring the geodynamic state of these segments from a metastable to a more stable and safe state. [ABSTRACT FROM AUTHOR]

The paper is devoted to the numerical study of the influence of the mutual relationship between dilatancy of solid skeleton and pore fluid inflow on the value of shear strength of shear bands in rocks. We show that this influence has a nonlinear and nonmonotonic character and strongly depends on the degree of confinement of a shear band. The results of the study broaden the understanding of possible limits of the change in the strength of localized shear bands and are relevant for solving the problem of estimating the conditions for the onset of an accelerated relative slip of structural blocks in rock massifs. [ABSTRACT FROM AUTHOR]

The paper presents the movable cellular automaton method. It is based on numerical models of surface layers of the metal-ceramic composite NiCr-TiC modified under electron beam irradiation in inert gas plasmas. The models take into account different geometric, concentration and mechanical parameters of ceramic and metallic components. The authors study the contributions of key structural factors in mechanical properties of surface layers and determine the ranges of their variations by providing the optimum balance of strength, strain hardening and fracture toughness. [ABSTRACT FROM AUTHOR]

Earlier the authors developed a discrete element based numerical model of dynamic mechanical behavior of brittle materials. The model is based on the concept of kinetic theory of strength. An important problem in the application of the proposed model to the study of features of dynamic response of real materials is lack of information about the dependence of model parameters on stress relaxation times (including time of fracture development). The present paper proposes an analytical approach to determining these dependencies for different brittle materials. [ABSTRACT FROM AUTHOR]

The paper is devoted to the comparative analysis of features of some popular mechanical models of interphase boundaries in metal-ceramic composite materials. We have numerically studied the influence of the parameters of interface models on effective strength, strain-hardening coefficient and ultimate strain of a microscopic composite fragment including adjacent areas of the matrix, inclusions and the interface zone. We have shown that the most "powerful" and flexible mechanical model of an interphase boundary is the model of an "interface shell" with a gradient of mechanical properties. [ABSTRACT FROM AUTHOR]

The paper presents a numerical model of the response for brittle materials to dynamic mechanical loading and implementation of the model within the discrete element method (DEM) by the example of the movable cellular automaton method (MCA). Verification of the model was carried out using the numerical modeling of the uniaxial compression tests of concrete and sandstone samples at various strain rates. It is shown that the developed model is correct and adequately describes the behavior of brittle materials under dynamic loading. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical study of shear strength of an elastic-plastic water-filled interface between elastic permeable blocks under compression. The medium is described within the discrete element method. The relationship between the stress-strain state of the solid skeleton and pore pressure of a liquid is described in the framework of the Biot's model of poroelasticity. The simulation demonstrates that shear strength of an elastic-plastic interface depends non-linearly on the values of permeability and loading to a great extent. We have proposed an empirical relation that approximates the obtained results of the numerical simulation in assumption of the interplay of dilation of the material and mass transfer of the liquid. [ABSTRACT FROM AUTHOR]

Sintered metal-ceramic materials are characterized by high mechanical and tribological properties. A key element of the internal structure of the metal-ceramic composites which have an important, and in many cases, a decisive influence on the integral mechanical properties of these materials is the interphase boundary. In this paper, based on numerical simulation we show the influence of morphology and strength properties of interfaces for integral mechanical properties of the dispersion-reinforced composite NiCr-TiC (50 : 50). Computer simulation results indicate that the phase boundary significantly contributes to the integral mechanical characteristics of a composite material and to the nature of the initiation and development of cracks. [ABSTRACT FROM AUTHOR]

Quasi-two-dimensional and hybrid nanomaterials based on layered double hydroxides (LDH), cationic clays, layered oxyhydroxides and hydroxides of metals possess large specific surface area and strong electrostatic properties with permanent or pH-dependent electric charge. Such nanomaterials may impact cellular electrostatics, changing the ion balance, pH and membrane potential. Selective ion adsorption/exchange may alter the transmembrane electrochemical gradient, disrupting potential-dependent cellular processes. Cellular proteins as a rule have charged residues which can be effectively adsorbed on the surface of layered hydroxide based nanomaterials. The aim of this study is to attempt to shed some light on the possibility and mechanisms of protein "adhesion" an LDH nanosheet and to propose a new direction in anticancer medicine, based on physical impact and strong electrostatics. An unbiased molecular dynamics simulation was performed and the combined process free energy estimation (COPFEE) approach was used. [ABSTRACT FROM AUTHOR]

Continuous research activities in the field of nanomedicine in the past decade have, to a great extent, been focused on nanoparticle technologies for cancer therapy. Gold and iron oxide nanoparticles (NP) are two of the most studied inorganic nanomaterials due to their unique optical and magnetic properties. Both types of NPs are emerging as promising systems for anti-tumor drug delivery and for nanoparticle-mediated thermal therapy of cancer. In thermal therapy, localized heating inside tumors or in proximity of tumor cells can be induced, for example, with Au NPs by radiofrequency ablation heating or conversion of photon energy (photothermal therapy) and in iron oxide magnetic NPs by heat generation through relaxation in an alternating magnetic field (magnetic hyperthermia). Furthermore, the superparamagnetic properties of iron oxide nanoparticles have led to their use as potent MRI (magnetic resonance imaging) contrast agents. Surface modification/coating can produce NPs with tailored and desired properties, such as enhanced blood circulation time, stability, biocompatibility and water solubility. To target nanoparticles to specific tumor cells, NPs should be conjugated with targeting moieties on the surface which bind to receptors or other molecular structures on the cell surface. The article presents several approaches to enhancing the specificity of Au and iron oxide nanoparticles for tumor tissue by appropriate surface modification/functionalization, as well as the effect of these treatments on the saturation magnetization value of iron oxide NPs. The use of other nanoparticles and nanostructures in cancer treatment is also briefly reviewed. [ABSTRACT FROM AUTHOR]

High strength ductile iron-silver nanocomposite scaffolds were fabricated employing high energy attrition milling of micron-submicron powders, followed by cold sintering/high pressure consolidation. Particulate leaching method with soluble Na2SO4 and K2CO3 salts as porogens was used to create scaffolds with 50, 55, 60 and 73% volume fraction of pores. Part of specimens was annealed at 600, 800 and 900°C. Specimens were characterized employing X-ray diffraction, scanning electron microscopy (SEM) with electron probe microanalysis (EDS) and high resolution SEM. Mechanical properties were measured in compression and permeability was measured in permeameter based on Darcy's law. Scaffolds with 50% and 55% porosity exhibited high compressive strength (18-22 MPa), compressive strength of 8-12 MPa was observed for scaffolds with 73% porosity. Treatments at 800 and 900°C result in increase of strength and ductility with some coarsening of microstructure. Best combination of compressive strength (15 MPa) and permeability (0.6-6 cm²) is close to the range of trabecular bone. [ABSTRACT FROM AUTHOR]

The research aim was to evaluate the bone regeneration capability of novel load-bearing NiTi alloy (Nitinol) scaffolds in a critical-size defect (CSD) model. High strength "trabecular Nitinol" scaffolds were prepared by PIRAC (Powder Immersion Reaction Assisted Coating) annealing of the highly porous Ni foam in Ti powder at 900°C. This was followed by PIRAC nitriding to mitigate the release of potentially toxic Ni ions. Scaffolds phase composition and microstructure were characterized by X-ray diffraction and scanning electron microscopy (SEM/EDS), and their mechanical properties were tested in compression. New Zealand white rabbits received bone defect in right radius and were divided in four groups randomly. In the control group, nothing was placed in the defect. In other groups, NiTi scaffolds were implanted in the defect: (i) as produced, (ii) loaded with bone marrow aspirate (BMA), and (iii) biomimetically CaP-coated. The animals were sacrificed after 12 weeks. The forelimbs with scaffolds were resected, fixed, sectioned and examined in SEM. New bone formation inside the scaffold was studied by EDS analysis and by the processing of backscattered electron images. Bone ingrowth into the scaffold was observed in all implant groups, mostly next to the ulna. New bone formation was strongly enhanced by BMA loading and biomimeatic CaP coating, the bone penetrating as much as 1-1.5 mm into the scaffold. The results of this preliminary study demonstrate that the newly developed high strength trabecular Nitinol scaffolds can be successfully used for bone regeneration in critical size defects. [ABSTRACT FROM AUTHOR]

The strong surface electric charge density of clay mineral host nanolayers enables their use as host-guest nanohybrids in many different areas of application. In particular, layered double hydroxides (LDH) of metals have found applications in medicine. Drug-LDH or gene-LDH nanohybrids are used for targeted delivery of biomedical agents to diseased cells or cancer cells. Fragments of the LDH host nanolayers may remain both within the cell and in the extracellular medium after drug delivery. How these charged nanosheets affect the cell electrostatics is still poorly understood. In the present paper, the idealized case of a single pure Mg2/Al-LDH nanolayer interacting with the extracellular anion environment was investigated to estimate the order of magnitude of a possible shift of the cell membrane equilibrium potential. An approximate dependence of the change in the chloride equilibrium membrane potential on the concentration of pure Mg2/Al-LDH nanosheets was determined. [ABSTRACT FROM AUTHOR]

Main attention of the research is focused on the role of vortex-like structures in the velocity fields of the strengthening coating and substrate under contact loading by hard conical indenter. The peculiarities of velocity vortex formation and propagation, as well as its interaction with structural elements are studied. One of possible application of the study is non-destructive technique for detecting nanoscale defects in surface layer of a material using frequency analysis of the friction force. Possibilities of this technique are studied based on 3D simulation. [ABSTRACT FROM AUTHOR]

Molecular dynamics investigation of metal crystallite with bcc lattice under nanoindentation was carried out. Potentials of interatomic interactions were calculated on the base of the approximation of the Finnis-Sinclair method. For clarity and simpler indentation data interpretation, an extended cylindrical indenter was used in the investigation. The features of the bcc iron structural response at nanoindentation of surfaces with different crystallographic orientations were revealed. Generation of structural defects in the contact zone always resulted in the decrease in the rate of growth of the reaction force. [ABSTRACT FROM AUTHOR]

The computer simulation results on the atomic structure of the copper crystallite and its behavior in nanoindentation demonstrate the key role of local structural transformations in nucleation of plasticity. The generation of local structural transformations can be considered as an elementary event during the formation of higher scale defects, including partial dislocations and stacking faults. The cause for local structural transformations, both direct fcc-hcp and reverse hcp-fcc, is an abrupt local increase in atomic volume. A characteristic feature is that the values of local volume jumps in direct and reverse structural transformations are comparable with that in melting and lie in the range 5–7%. [ABSTRACT FROM AUTHOR]

A molecular dynamics model was constructed to describe material loading on the atomic scale by the mode identical to friction stir welding. It was shown that additional vibration applied to the tool during the loading mode provides specified intensity values and continuous thermomechanical action during welding. An increase in additional vibration intensity causes an increase both in the force acting on the workpiece from the rotating tool and in temperature within the welded area. [ABSTRACT FROM AUTHOR]

2D and 3D models of mechanical behavior of brittle porous material under uniaxial compression loading were developed in the framework of the movable cellular automaton method. The considered material was characterized by pore size distribution function having two maxima. On the basis of simulation results the dependence of the strength properties of brittle porous material on its total porosity and partial porosities corresponding to pores with different size was revealed. The change in internal structure of material in a wide range of mentioned parameters was analyzed. The main structural factors influencing compression strength of the material at various combinations of values of porosity parameters were identified. [ABSTRACT FROM AUTHOR]

In this paper we discuss some features that are important in modeling nanoindentation of strength coating deposited on metallic substrate. The modeling is performed by movable cellular automaton method, which is a representative of the discrete element methods in computational solid mechanics. Taking into account such factors as capability of the substrate material to harden, friction between the surface and the indenter as well as the presence of an intermediate layer between the coating and the substrate, it is shown that they can deeply affect the mechanical behavior of the system. [ABSTRACT FROM AUTHOR]

Hydrophobic and functionalized nanoparticles of different sizes and shapes have a various biomedical application, in particular anticancer therapy. It is known that charged nanoparticles may bind lipids and membrane proteins as well as cause lipid bilayer disruption. We have performed preliminary molecular dynamic simulations to investigate the effect of positively charged synthetic nanofilm, imitating a fragment of the two-dimensional folded AlOOH structure, on the POPE/POPG lipid membrane. It has been shown that the synthetic nanofilm with frozen coordinates tightens the membrane and binds lipid headgroups. Furthermore, the presence of the positively charged nanofilm perturbs the cation concentration in the near-surface membrane region. [ABSTRACT FROM AUTHOR]

The paper undertakes a study of plastic deformation in a titanium crystallite under mechanical loading (uniaxial tension and indentation) in terms of atomic mechanisms of its generation and development. The molecular dynamics method with many-body interatomic potentials is employed. It is shown that there is a threshold strain, at which a crystal reveals the generation of local structural transformations associated with changes in atomic configurations of the first and second coordination spheres. The onset of plastic deformation in a crystallite is accompanied by a stepwise decrease in potential energy. The effect of free surfaces and grain boundaries on the generation of local structural transformations in a titanium crystallite is investigated. [ABSTRACT FROM AUTHOR]

Shock wave properties generated by impulse mechanical loading and base state structure of dusty plasma system versus the change of dusty particle charges with height were investigated in the framework of the molecular dynamics method. Spherically symmetric electrostatic confinement was used as the boundary conditions. Interactions between dusty particles were described using Debye-Huckel potential. Particle charges decreased linearly with the increase of height. Shape of dusty plasma crystals with taking into account a variable particle charge was simulated. [ABSTRACT FROM AUTHOR]

Movable cellular automaton method was used for simulating uniaxial compression of 3D porous ceramic samples. Pores were considered explicitly by removing randomly selected automata from the original FCC packing. Distribution of pores in space, their size and the total fraction were varied. It is shown that the relation between mechanical properties of the material and its porosity significantly depends on the pore size. Thus, value of the elastic modulus of the samples with large pores is greater than that of the samples with small pores by average value of 3%-16%. Strength value of the samples with large pores is less than that of the samples with small pores by average value of 12% up to the porosity of 0.55, and then becomes to be greater. When the samples contain small and large pores there is a maximum of mechanical properties at ratio of volumes of large and small pores of about 0.75. [ABSTRACT FROM AUTHOR]

In the paper we present the results of the theoretical study of some fundamental aspects of mode II crack propagation in conventional sub-Rayleigh regime and transition to intersonic regime. It is shown that development of a sub-Rayleigh shear crack is determined in many respects by elastic vortex traveling ahead of the crack tip at a shear wave velocity. Formation of such a vortex helps to better understand the well-known phenomenon of acceleration of a shear crack towards the longitudinal wave velocity. Simulation results have shown that due to self-similarity of shear crack propagation the conditions of sub-Rayleigh to intersonic transition depend on dimensionless material and crack parameters. Two key dimensionless parameters are proposed. [ABSTRACT FROM AUTHOR]

Movable cellular automaton method was used for investigating the mechanical behavior of ceramic composites under uniaxial compression. A 2D numerical model of ceramic composites based on oxides of zirconium and aluminum with different structural parameters was developed using the SEM images of micro-sections of a real composite. The influence of such structural parameters as the geometrical dimensions of layers, inclusions, and their spatial distribution in the sample, the volume content of the composite components and their mechanical properties (as well as the amount of zirconium dioxide that underwent the phase transformation) on the fracture, strength, deformation and dissipative properties was investigated. [ABSTRACT FROM AUTHOR]

The paper studies the morphology' phase and elemental composition of bimetallic Al/Zn nanoparticles. It is found that metallic Al and Zn phases have interfaces within a single particle. The conversion mechanisms of Al/Zn nanoparticles in aqueous-alcoholic solutions with different water concentration are studied. It is shown that at 7 mass% water content aluminum oxidation and pseudoboehmite formation begin. Aluminum conversion increases with water content growth. At 20 mass% water content aluminum is oxidized completely' giving way to zinc oxidation. Microbiological studies show that samples containing AlOOH-Zn-ZnO phases exhibit the highest antimicrobial activity. Two-component metallic Al/Zn nanoparticles and composite particles in which initial components are completely oxidized to AlOOH-ZnO have the smallest inhibition zone. [ABSTRACT FROM AUTHOR]

The paper studies the hemostatic action of the fibrous material containing agglomerates of low-dimensional electropositive structures of aluminum oxyhydroxide. The time of parenchymatous bleeding is found to decrease from 292.5 s at spontaneous hemostasis to 177.8 s with the attached fibrous material and to 215.7 s with gauze. The mixed mechanism of the hemostatic action is possible' i.e. along with the hygroscopic mechanism' platelets aggregate due to destruction of a diffuse part of the double electrical layer in contact with low-dimensional electropositive structures of aluminum oxyhydroxide. [ABSTRACT FROM AUTHOR]

A molecular dynamics simulation of nanoparticle formation in simultaneous electric explosion of conductors is performed. Interatomic interaction is described using potentials calculated in the framework of the embedded atom method. High-rate heating results in failure of the conductors with the formation of nanoparticles. The influence of the heating rate, temperature distribution over the specimen cross-section and the distance between simultaneously exploded conductors on the structure of formed nanoparticles is studied. The calculation results show that the electric explosion of conductors allows the formation of nanoparticles with block structure. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulation was performed to study the features of nucleation and development of plastic deformation in copper crystallites in nanoindentation with different crystallographic orientations of their loaded surface: (011), (001), and (111). Atomic interaction was described by a potential constructed in terms of the embedded atom method. It is shown that behavior of the crystallite reaction force correlates well with a change in the fraction of atoms involved in local structural rearrangements. The generation of local structural changes decreases the slope of the crystallite reaction force curve or results in an extremum due to internal stress relaxation. Analysis of structural changes in the material being indented demonstrates that the orientation of its loaded surface greatly affects the features of nucleation and development of plastic deformation. [ABSTRACT FROM AUTHOR]

In the framework of the movable cellular automata method we have developed a plane/2D model of mechanical behavior of brittle porous material under shear loading. The work considers the material characterized by a function of pore size distribution with two maxima. Based on simulation results, the authors proposed the analytical estimation of the dependence of strength and elastic properties of the material on its total porosity and partial porosities that correspond to the pores with different sizes. [ABSTRACT FROM AUTHOR]

In the present paper the multiscale approach to the construction of rheological models of brittle materials with heterogeneous internal structure is implemented within the numerical method of movable cellular automata. An example of application of the implemented approach to determine the mechanical properties (including parameters of the rheological model and strength) of brittle materials with complicated internal structure at both macroscopic and mesoscopic scales is described. The effect of strain rate on brittle materials behavior under uniaxial compression and tension is analyzed. [ABSTRACT FROM AUTHOR]

Low-dimensional structures consisting of pseudoboehmite nanopetals are synthesized by hydrolysis of electroexplosive aluminum nanopowder. The physical and chemical properties of the synthesized nanostructures are studied, such as morphology, particle size, specific surface area, phase composition, and zeta-potential. The production of a hybrid material on the basis of cellulose acetate microfibers and low-dimensional pseudoboehmite structures is described. Using the example of gram-negative and gram-positive bacteria, we show the microorganism adsorption capacity of pseudoboehmite nanopetals and the hybrid material. [ABSTRACT FROM AUTHOR]

The work describes the application of the movable cellular automaton method for the simulation of typical situations of nano-scale crack identification in ceramic coatings by the spectral analysis of friction force continuously registered using a small counter-body moving over the coating surface. It is shown that the Fourier spectra of the friction force have peaks that correspond to the distance between the nanocracks oriented perpendicular and at some angle to the tested surface. The obtained results allow to conclude that the appearance of cracks on the Fourier spectra of friction force depends on their orientation. Thus' the distance between cracks' their orientation and sizes can be identified by the method of tribospectroscopy. [ABSTRACT FROM AUTHOR]

A method of numerical simulation of liquid-saturated porous media' that represents a combination of particle method and finite-difference method' namely' the hybrid cellular automaton method was proposed. It allows taking into account inelastic deformations' dilation and fracture of solid skeleton as well as the influence of pore pressure on the stress state of the skeleton and the redistribution of a liquid in filtration volume of porous medium. The method was applied to study the influence of viscous compressible liquid in pores of material on its strength and fracture. It has been shown that the strength of brittle liquid-saturated specimens depends on the material properties and the geometry of porosity' the physical-mechanical properties of the liquid etc. The latter shows the topicality of application of numerical methods to study and predict strength properties of fluid-saturated media under loading. [ABSTRACT FROM AUTHOR]

Al/Cu, Al/Zn and Al/Fe bimetallic nanoparticles have been obtained using the method of simultaneous electrical explosion of metal pairs in an argon atmosphere. The nanoparticles are chemically active and interact with water at 60°C forming flower-like hierarchical porous structures with a high specific surface area. As the Al/Cu nanopowder is oxidized with water' flower-like pseudoboehmite composite structures are formed with the size of under 1.0m; structurally heterogeneous electron-dense spherical inclusions of unreacted metal copper and intermetallides are identified inside them. Al/Fe product transformations are presented by the flower-like pseudoboehmite surrounded by lamellar structures enriched with ferric oxides. Al/Zn nanoparticles react with water' forming the flower-like pseudoboehmite and mainly hexagonal zinc oxide laminae. The composite particles obtained can be used as antibacterial agents in manufacturing medical supplies. [ABSTRACT FROM AUTHOR]

Aluminum oxides of various morphology and phase composition' including pseudoboehmite' have wide application in medicine. The novel hybrid material from polymer fibers and low-dimensional structures of pseudoboehmite fixed on them can be used as a wound dressing due to its highly absorbent and adsorbent properties. The in vivo investigation of acute and chronic toxicity of the novel hybrid material after a single dermal application in the acute experiment for 8 and 24 hours with outbred male and female rats reveals no irritation or other pathological changes. The chronic toxicity testing of the material after multiple dermal applications at two doses causes no death of animals and no pathological changes in their general condition' weight dynamics' and visceral morphology. The macro- and microscopy of internal organs shows no pathological changes as compared to control animals. The results obtained bear witness to the low potential risk of toxicity when using the hybrid material as a wound dressing. [ABSTRACT FROM AUTHOR]