EXPERIMENTAL STUDIES ON PROCESS OF METHANE-AIR SYSTEM EXPLOSION IN UNDERGROUND STRUCTURES

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Petr Šelešovský ◽  
Václav Pospíchal
Keyword(s):  
Experimental Studies ◽  
Underground Structures ◽  
Air System

Geomechanical justification of room-and-pillar dimensions for rock salt and polymineral salt mining

2021 ◽  
pp. 37-43
Author(s):  
V. A. Eremenko ◽  
◽  
M. A. Kosyreva ◽  
N. G. Vysotin ◽  
Ch. V. Khazhy-ylai ◽  
...  
Keyword(s):  
Rock Salt ◽  
Experimental Studies ◽  
Structural Elements ◽  
Structural Components ◽  
Underground Structures ◽  
Russian Science ◽  
Strain Behavior ◽  
Analytical Estimation ◽  
Pillar Mining ◽  
External Loads

The key target of room-and-pillar planning for mining rock salt, polymineral salt and polyhalite at the minimized loss of minerals in pillars is optimization of the dimensions of rooms and rib pillars. The authors compare some variants of mining with rooms and rib pillars, as well as with honeycomb mine structure. The theoretical and experimental studies prove efficiency of room-and-pillar dimension optimization by combination of analytical estimation with numerical analysis and physical modeling of the stress–strain behavior of underground structures (honeycomb mine structures). It is found that the honeycomb mine structures feature higher resistability of structural components to external loads. The research into secondary stress field generation and influence on structural elements of the roomand- pillar mining systems made it possible to calculate stable parameters for the conventional and innovative mining systems. The study was supported by the Russian Science Foundation, Project No. 19-17-00034.

scholarly journals Construction of mathematical models of the stressed-strained state of a material with a porous water-saturated base under dynamic load

2021 ◽  
Vol 5 (7 (113)) ◽  
pp. 25-35
Author(s):  
Allayarbek Aidossov ◽  
Galym Aidosov ◽  
Saltanat Narbayeva
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Median Plane ◽  
Lower Surface ◽  
Viscoelastic Layer ◽  
Dimensional Problem ◽  
Underground Structures ◽  
Engineering Structures ◽  
Deformable Base ◽  
Water Saturated

Materials of beams, plates, slabs, strips have been commonly applied in various fields of industry and agriculture as flat elements in the structures for machinery and construction. They are associated with the design of numerous engineering structures and facilities, such as the foundations of various buildings, airfield and road surfaces, floodgates, including underground structures. This paper reports a study into the interaction of the material (of beams, plates, slabs, strips) with the deformable base as a three-dimensional body and in the exact statement of a three-dimensional problem of mathematical physics under dynamic loads. The tasks of studying the interaction of a material (beams, plates, slabs, strips) with a deformable base have been set. A material lying on a porous water-saturated viscoelastic base is considered as a viscoelastic layer of the same geometry. It is assumed that the lower surface of the layer is flat while the upper surface, in a general case, is not flat and is given by some equation. Classical approximate theories of the interaction of a layer with a deformable base, based on the Kirchhoff hypothesis, have been considered. Using the well-known hypothesis by Timoshenko and others, the general three-dimensional problem is reduced to a two-dimensional one relative to the displacement of points of the median plane of the layer, which imposes restrictions on external efforts. In the examined problem, there is no median plane. Therefore, as the desired values, displacements and deformations of the points in the plane have been considered, which, under certain conditions, pass into the median plane of the layer. It is not possible to find a closed analytical solution for most problems while experimental studies often turn out to be time-consuming and dangerous processes

scholarly journals Integrated modernization of the gas-and-air system of a turbocharged diesel engine (21/21)

2020 ◽  
Vol 178 ◽  
pp. 01005
Author(s):  
Leonid Plotnikov ◽  
Nikolay Kochev ◽  
Leonid Osipov
Keyword(s):  
Mathematical Modeling ◽  
Environmental Performance ◽  
Experimental Studies ◽  
Turbocharged Diesel Engine ◽  
Exchange Processes ◽  
Urgent Task ◽  
New Directions ◽  
Air System ◽  
The Given ◽  
Charging Efficiency

Improving the exploitative and environmental performance of piston engines (PICE) is an urgent task for many engineers and scientists. The article presents the results of the upgrade of a gas-and-air system of a diesel PICE, carried out through changing the turbocharging system’s configuration and modernizing the design of the admittance collector. The authors present a review of studies on the given subject and a description of the object of the research. The study was conducted on the basis of bench tests at a manufacturing plant and mathematical modeling using ACTUS program. The results of experimental studies on the main indicators of a basic and upgraded PICEs are presented. The gas exchange processes in the PICE under examination were studied in detail using mathematical modeling. For the given diesel PICE, improvement of the gas-and-air system leads to a growth in charging efficiency by 2.45-3.92%, a decrease in scavenging factor by 3.11-6.31% and a reduction of specific fuel consumption up to 3.33%. In the conclusion, new directions for increasing the efficiency of the given PICE are offered.

Experimental Studies of the Boundary Conditions Leading to Oil Fire in the Bearing Chamber and in the Secondary Air System of Aeroengines

2002 ◽  
Author(s):  
K. Willenborg ◽  
S. Busam ◽  
H. Roßkamp ◽  
S. Wittig
Keyword(s):  
High Reliability ◽  
Experimental Studies ◽  
Spontaneous Ignition ◽  
Fundamental Study ◽  
Engine Operation ◽  
Continuous Increase ◽  
Hot Surface Ignition ◽  
Air System ◽  
Secondary Air ◽  
Hot Surface

The continuous increase of the temperature and pressure levels in modern aeroengines has significantly increased the demands on the design of the lubrication system. Among other things the oil/air system of a gas turbine engine has to ensure that engine operation does not permit oil coking or oil fires in order to guarantee high reliability and safety of the engine. To improve existing and develop new design rules, a fundamental study of the conditions leading to oil firing within an oil contaminated environment has been initiated. Three ignition mechanisms relevant for the triggering of an oil fire in the bearing chamber or in the secondary air system are investigated in detail: the spontaneous ignition of the lubricant (autoignition), the ignition of the lubricant near a hot surface (hot surface ignition) and the propagation of a flame within a vent pipe into the bearing chamber (vent pipe flashback). The present paper focusses on the experimental approach and procedure. The different test rigs are presented and their functioning is demonstrated by means of initial results.

scholarly journals Assessment of the Effect of Inertia Forces in Problems of Underground Pipeline Seismodynamics

2020 ◽  
Vol 9 (3) ◽  
pp. 500-503 ◽  
Keyword(s):  
Life Support ◽  
Experimental Studies ◽  
Seismic Loading ◽  
Seismic Effect ◽  
Underground Pipeline ◽  
Underground Structures ◽  
Calculation Algorithm ◽  
Soil System ◽  
Load Effect ◽  
Inertia Forces

A research to assess the effect of inertia forces in solving specific problems of seismodynamics of underground life support systems is conducted in the paper. A calculation algorithm is constructed using the finite difference method; a system of applied programs based on the developed algorithms and their debugging is created. Dangerous points of maximum normal stress occurrence under seismic loading in underground pipeline are determined taking into account elastic pipe-soil system interaction. The limits of inertial load effect on the behavior of underground systems are estimated. The possibility of considering the seismodynamic problems of underground structures in quasistatic and static statements is substantiated theoretically. The methods of solving the equations of underground pipeline vibrations are given with account for elastic interactions in the pipe-soil system under seismic effect - seismodynamic and quasistatic methods. The conducted computational and experimental studies allow solving the problems of assessing the stress-strain state of pipelines under seismic loading, which is important for practical calculations.

3-D reconstruction and analysis of mammalian mitotic spindle structure

1992 ◽  
Vol 50 (1) ◽  
pp. 578-579
Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh
Keyword(s):  
Cross Sections ◽  
Mitotic Spindle ◽  
Experimental Studies ◽  
Video Camera ◽  
Three Dimensions ◽  
Mitotic Spindles ◽  
Black And White ◽  
Reconstruction Methods ◽  
Spindle Structure ◽  
Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

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