Mining Institute of Georgia

Tbilisi, Georgia

Mining Institute of Georgia

Tbilisi, Georgia
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Ilias N.,University of Petrosani | Lanchava O.,Mining Institute of Georgia | Lanchava O.,Georgian Technical University | Nozadze G.,Georgian Technical University
Quality - Access to Success | Year: 2017

This article discusses the issue of road tunnel safety in case of 5 to 30 MW-magnitude fires, as required by the normative and legislative documents of the European Union. Through numerical modelling, the article explores the dynamics of distribution of main damaging factors (temperature, concentration of toxic gases, visibility) caused by highly flammable fuels (petrol, diesel and others). The modelling is carried out in the environment of the Pyrosim 2015 software programme which is based on the flow dynamics method (FDS), where it is possible to create a dynamic 3D map of magnitudes that characterise the damaging factors. Based on the analysis of existing calculations, it is possible to measure the spatial scale and time of distribution of damaging factors in hypothetical scenarios of fire development, as well as determine the critical time for evacuation for each damaging factor, which is essential for conducting an effective rescue process. © 2017, SRAC - Societatea Romana Pentru Asigurarea Calitatii. All rights reserved.

Chikhradze N.,Georgian Technical University | Chikhradze N.,Mining Institute of Georgia | Abashidze G.,Mining Institute of Georgia | Pkhaladze G.,Mining Institute of Georgia
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM | Year: 2014

With the advent of 21-st century the intensive investigations carried out all over the world for preparation of technical purpose fibers of new type. Among them is basalt fiber which may be considered as an alternative of glass fiber. Basalt fiber is distinguished from glass one by improved physical-mechanical characteristics, especially by elasticity module, enhanced heat resistance and stability against various aggressive media. Taking into consideration the fact that the technology of preparation of basalt fiber is not much different from the technology of preparation of glass fiber and their cost is the same order, the technologies of preparation of the products from basalt fiber occupy a highly important place in advanced industrially developed countries. There are large resources of basalt raw material in Georgia. In presented work the characteristics of basalt rocks of three deposits (Marneuli, Tetritskaro, Bolnisi) are given as well as such properties of obtained melt as viscosity and crystallization ability, the conditions of fiber formation, fiber physical-chemical and mechanical characteristics, including short-term resistance and long-term strength at tension. © SGEM2014.

Chikhradze N.,Mining Institute of Georgia | Chikhradze N.,Georgian Technical University | Kabulashvili V.,Georgian Technical University
TMS Annual Meeting | Year: 2011

The possibilities for generation of ultra-high pressures and temperatures using the different schemes of detonation of explosives are discussed. It is demonstrated that ultra-high pressures and temperatures generated by explosives of different shape could be effectively used for the industrial production of super hard materials and ultra-disperse powders.

Chikhradze N.,Mining Institute of Georgia | Japaridze L.,Mining Institute of Georgia | Abashidze G.,Mining Institute of Georgia
12th International Multidisciplinary Scientific GeoConference and EXPO - Modern Management of Mine Producing, Geology and Environmental Protection, SGEM 2012 | Year: 2012

For polyolefins (PO) stabilization and protection against ageing the method is proposed for their thermochemical modification in organosilicon liquid. The efficiency of their chemical modification has been shown by the example of polyethylene (PE) and polypropylene (PP) by means of phenylaminomethylmethyldietoxysilane. Stabilization efficiency is estimated by physical-chemical methods, by the possibility of recycling processing of PO, by the results of mechanical testing of non-modified and modified PO at pre- and post-artificial ageing of materials. The values of short-term strength of PO on extension, compression, bending, specific impact viscosity, fatigue strength at bending, on relative elongation and elasticity modulus at extension are presented. The proposal has been made that the modification of PO by organosilicon compounds offers the good prospects from the viewpoint of utilization of industrial-domestic waste, for reducing of demand for initial polymeric raw material and for prevention of environmental contamination. © SGEM2012 All Rights Reserved by the International Multidisciplinary Scientific GeoConference SGEM.

Kecskes L.,U.S. Army | Butler B.,U.S. Army | Oniashvili G.,Tavadze Institute of Metallurgy and Materials Science | Aslamazishvili Z.,Tavadze Institute of Metallurgy and Materials Science | And 2 more authors.
Materials and Manufacturing Processes | Year: 2011

Bi- and trilayer composites of titanium aluminides (Ti-Al) and substoichiometric titanium boride (TiB0.6) have been fabricated from green compacts placed under pressure. Ti-Al blends with ratios of 3:1, 1:1, or 1:3 have been prepared by ball milling. Subsequent to the preparation of the precursor blends, plate-shaped green compacts of Ti-Al and Ti-B0.6 were pressed at room temperature. Green compacts were stacked in a layered geometry and were heated rapidly under a static pressure of about 10bar. After the temperature reached 1300-1400°C, the Ti-Al and TiB0.6 phases were synthesized by the conversion of the reactants into the product phases (also known as "thermal explosion" processing) and simultaneously consolidated and joined under a pressure of 80-100bar. Scanning electron microscopy (SEM) examination showed that the Ti-Al layer was highly heterogeneous, and the extent of heterogeneity depended strongly on the respective elemental ratio of Ti to Al. Furthermore, the conversion from reactants to products was found to be determined by the overall heat available during the thermal explosion processing step. Unlike the Ti-Al, the TiB 0.6 layer was more uniform; however, the combination of heat and pressure was found to be insufficient to fully densify the aluminide layer. These and other features of the layered intermetallic structures will be discussed. Copyright © Taylor & Francis Group, LLC.

Chikhradze N.M.,Mining Institute of Georgia | Marquis F.D.,Naval Postgraduate School, Monterey | Japaridze L.A.,Mining Institute of Georgia | Abashidze G.S.,Mining Institute of Georgia | Okujava L.M.,K Zavriev Institute Of Structural Mechanics And Seismic Stability
Materials Science Forum | Year: 2010

In recent years considerable attention has been dedicated to renewal power sources, such as wind power. This work was carried out in order to develop a small wind turbine of 1-10kW power generation capability. This wind turbine is designed to be energetically more efficient by 30-50% and having a lesser specific cost (by 25-30%). This work focused on the development of composite materials for application on the blades in the wind generator. In this paper we present the results of the research work done on the development of flexible technology for the fabrication matrix-epoxy resin based hybrid composites, reinforced with carbon, basalt and glass fibers. These new composite and hybrid materials were fabricated using epoxy matrixes. These matrices were reinforced with basalt and carbon fibers of different content and strengthened by mullite-like crystals. The basalt fibers for composite reinforcing were prepared from raw materials, with chemical composition: SiO2-15.3%; CaO-10.8%; Na2O-4.2%; MgO-8.8%; Fe2O3-12.1%; MnO-0.7%; TiO2-0.7%. The properties of new composites developed depend on the content and architecture of reinforcing components and are: tensile strength-(0.012-1.590)GPa; compression strength-(0.078-0.656)GPa; modulus of elasticity-(8.4-162.9)GPa; Poisson ratio-(0.015-0.559). The variation of strength and elastic characteristics under tension and compression of the new composites are presented. © (2010) Trans Tech Publications.

Chikhradze M.,Mining Institute of Georgia | Godibadze B.,Mining Institute of Georgia | Bochorishvili N.,Mining Institute of Georgia
AIP Conference Proceedings | Year: 2011

Pure nano sized (50 nm) Si and coarse Si 0,7Ge 0,3 powders (≤20micron) were compacted near theoretical density by shock-compaction technology. The powder was placed in a steel container and explosively compacted by explosively induced shock waves of cylindrical symmetry. Ammonium nitride based industrial explosives and electrical detonators were used for the generation of shock waves. Explosive compaction experiments were performed in range of pressure impulses of 5-10 Gpa. This process occurs in a combination of two stages. The first is the preliminary densification by static pressure to a container with pure elemental Si and Si0.68Ge0.32 powder, and is followed by the second stage, shock-wave compaction. The relationships between the compacting conditions, the precursor particle sizes, and the consolidation and properties of this new ultra high performance alloy are discussed in the paper. © 2011 American Institute of Physics.

Groppen V.O.,Mining Institute of Georgia
International Journal of Mathematics and Computers in Simulation | Year: 2011

Proposed approach is based on the idea of variability of measurement standards. This approach permits us to predict some features of the Universe: spontaneous growth of distance between two resting objects detected by an observer at one of these objects, velocity/distance dependence is known to meet the Hubble Law, constancy of any solid body linear dimensions in time and equality of absolute values of gravitational braking and of illusive acceleration of galaxies is believed to be caused by linear measurement standard shortening some 6-8 billion years ago, as well as by mass loss by physical objects. The latter permits us to propose simulators, describing gravity and inertia as different manifestations of reaction forces.

Japaridze L.,Mining Institute of Georgia
Journal of Rock Mechanics and Geotechnical Engineering | Year: 2015

In this study, the interaction between cylindrical specimen made of homogeneous, isotropic, and linearly elastic material and loading jaws of any curvature is considered in the Brazilian test. It is assumed that the specimen is diametrically compressed by elliptic normal contact stresses. The frictional contact stresses between the specimen and platens are neglected. The analytical solution starts from the contact problem of the loading jaws of any curvature and cylindrical specimen. The contact width, corresponding loading angle (2θ0), and elliptical stresses obtained through solution of the contact problems are used as boundary conditions for a cylindrical specimen. The problem of the theory of elasticity for a cylinder is solved using Muskhelishvili's method. In this method, the displacements and stresses are represented in terms of two analytical functions of a complex variable. In the main approaches, the nonlinear interaction between the loading bearing blocks and the specimen as well as the curvature of their surfaces and the elastic parameters of their materials are taken into account. Numerical examples are solved using MATLAB to demonstrate the influence of deformability, curvature of the specimen and platens on the distribution of the normal contact stresses as well as on the tensile and compressive stresses acting across the loaded diameter. Derived equations also allow calculating the modulus of elasticity, total deformation modulus and creep parameters of the specimen material based on the experimental data of radial contraction of the specimen. © 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences.

Chikhradze N.M.,Mining Institute of Georgia | Abashidze O.S.,Mining Institute of Georgia | Japaridze L.A.,Mining Institute of Georgia
TMS Annual Meeting | Year: 2013

The results of the investigations of composite materials of new type based on polyester resin, carbon and Basalt Fibers are presented. In particular, the values of the coefficients of operating conditions at elevated temperatures (up to 350K) for orthogonally reinforced composite, involving five layers of carbon cloth and a composite, in which two layers of mentioned cloth are replaced by basalt one, are given. In both cases the cloths are manufactured from non-twisted rovings. The possibility for partial replacement of costly and scarce carbon reinforcing element of the composite by basalt one without a considerable reduction of the coefficients of operating conditions at elevated temperatures are shown. Basalt reinforcing component is manufactured from local (Georgian) raw material and has the following chemical composition: SiO 2-49% Al2O3-17%, Fe2O 3-10%, CaO-10%, MgO-7%, Na2O-4%, MnO-1%, TiO 2-1%.

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