Pevzner A.O.,nchar Dnepropetrovsk National University |
Pevzner M.S.,National Mining University
Russian Physics Journal | Year: 2011
Motion of a charged particle in the field of a grounded conductive sphere is investigated. It is assumed that the field created by the sphere is quasi-static that implies limitation on particle velocities by nonrelativistic values and the possibility of neglecting magnetic interaction and heat losses. A classification is provided and possible particle trajectories are constructed in the examined case. © 2011 Springer Science+Business Media, Inc.
Kozhevnikov A.A.,National Mining University |
Sudakov A.K.,National Mining University |
Dreus A.Yu.,nchar Dnepropetrovsk National University |
Lysenko Ye.Ye.,nchar Dnepropetrovsk National University
Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu | Year: 2014
Purpose. To examine the process of heat transmission in the porous coarse environment of cryogenic gravel filters element of block construction, manufactured by low-temperature technology, during its transportation along the drillhole. Methodology. We have applied the mathematical simulation of the heat transmission process. We have carried out the comparative analysis of the results of the simulation and test-bed experimental research of the process of heating the cryogenic gravel element in the aqueous environment. Findings. We have created the mathematical model of the process of heat transmission in the porous coarse environment of cryogenic gravel filters element during its transportation along the drillhole. According to the conditions of heat transmission (physical-mechanical properties of the composite in cryogenic gravel filter element, temperature of cryogenic gravel element heating, and temperature of environment, etc.) we have substantiated the technological conditions of the cryogenic-gravel filter transportation along the drillhole. Originality. For the first time we have obtained the dependence of phase transition time of composite on its thermal and physical characteristics during the heat transmission in porous coarse environment during its transportation along the drillhole. This composite was the experimental example of cryogenic gravel element. Practical value. The results of numeral investigations contributed to development of the methods of designing the manufacturing technologies of the cryogenicgravel elements and equipment for the productive horizons of boreholes.
Nesterova O.U.,nchar Dnepropetrovsk National University |
Pugachova A.S.,nchar Dnepropetrovsk National University |
Voevudsky M.V.,Ukrainian State University of Chemical Technology |
Krischik O.V.,Ukrainian State University of Chemical Technology |
Musatov V.I.,Ukrainian Academy of Sciences
Chemistry of Heterocyclic Compounds | Year: 2011
Cyclization of the hydrazide of 5-ethoxycarbonyl-2,6-dimethylpyridine-3- carboxylic acid by acylation with aromatic or aliphatic acid chlorides with subsequent boiling in POCl 3 or heating in orthoformic acid gave the corresponding ethyl 2,6-dimethyl-5-(5-R-1,3,4-oxadiazol-2-yl)pyridine-3- carboxylate. The cyclization of the reaction products with hydrazine hydrate has been studied. Cyclization of the dihydrazide of 2,6-dimethyl-3,5- pyridinedicarboxylic acid under analogous conditions gave only 3,5-bis-(5-R-1,3,4-oxadiazol-2-yl)-2,6-dimethylpyridines, containing R = 2-FC 6H 4, H. © 2011 Springer Science+Business Media, Inc.
Korkina M.P.,nchar Dnepropetrovsk National University |
Kazemir V.S.,nchar Dnepropetrovsk National University
Russian Physics Journal | Year: 2011
Different types of T-solutions are investigated. The conditions at which one region of space-time can be described only by a statistic R-solution and another region can be described only by a T-solution are obtained. The common metric for R- and T-solutions is obtained where the spatial and temporal variables are interchanged. The T-solution which has the same mass function as for the internal static Schwarzschild solution is obtained. © 2011 Springer Science+Business Media, Inc.
Bulat A.F.,Ukrainian Academy of Sciences |
Kiseleva E.M.,nchar Dnepropetrovsk National University |
Pichugov S.A.,Dnepropetrovsk State Technical University of Railway Transport |
Blyuss O.B.,nchar Dnepropetrovsk National University
Journal of Automation and Information Sciences | Year: 2010
The proposed new vector criterion improves the results obtained based on the fuzzy c-means method. The possibility to apply the proposed vector criterion to fuzzy clustering problems is substantiated. The appropriate algorithm is constructed to allow one to perform clustering of rocks based on a predictive estimate of outburst hazard degree. © 2010 by Begell House Inc.