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Search Results: 1 - 10 of 200839 matches for " V. I. Gulyayev "
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Whirl Interaction of a Drill Bit with the Bore-Hole Bottom  [PDF]
Nabil W. Musa, V. I. Gulyayev, L. V. Shevchuk, Hasan Aldabas
Modern Mechanical Engineering (MME) , 2015, DOI: 10.4236/mme.2015.53005
Abstract: This paper deals with the theoretic simulation of a drill bit whirling under conditions of its contact interaction with the bore-hole bottom rock plane. The bit is considered to be an absolutely rigid ellipsoidal body with uneven surface. It is attached to the lower end of a rotating elastic drill string. In the perturbed state, the bit can roll without sliding on the bore-hole bottom, performing whirling vibrations (the model of dynamic equilibrium with pure rolling when maximum cohesive force does not exceed the ultimate Coulombic friction). To describe these motions, a nonholonomic dynamic model is proposed, constitutive partial differential equations are deduced. With their use, the whirling vibrations of oblong and oblate ellipsoidal bits are analyzed, the functions of cohesive (frictional) forces are calculated. It is shown that the system of elastic drill string and ellipsoidal bit can acquire stable or unstable whirl modes with approaching critical Eulerian values by the parameters of axial force, torque and angular velocity. The analogy of the found modes of motions with ones of the Celtic stones is established. It is shown that the ellipsoidal bits can stop their whirling vibrations and change directions of their circumferential motions in the same manner as the ellipsoidal Celtic stones do. As this takes place, the trajectories of the oblate ellipsoidal bits are characterized by more complicated paths and irregularities.
The modern trends of development of the pipe and tube industry
YU. G. Gulyayev,YE. I. Shyfrin,I. Mamuzi?,D. YU. Garmashev
Metalurgija , 2010,
Abstract: First the paper presents a review of steel production of the tubes in world: possible potencial is about 110 × 106 the tons (35 × 106 seamless tubes, rest welding tubes). In 2007. y. was record volume of 88,6 ×106 tons in world; 6,5% of total production of steel in world. Ratio-weldeds tubes: seamless tubes 70:30%. Further in the article are presented urgent the problems of the pipe and tube industry.
Perfection of processes of seamless steel tubes production
YU. G. Gulyayev,Ilija Mamuzi?,YE. I. Shyfrin,M. Bur?ak
Metalurgija , 2011,
Abstract: The article first give a review more of hundret years long history of seamless steel tube production, especially during the last 15-20 years of the 20th century. Prolongation, article give technological indices for 4 mills (automatical, continuous mill, pilger, Assel), and perfectation of processes seamless steel tubes production at the begining of 21st century.
About the Prospects for Passage to Instability  [PDF]
I. V. Lebed
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.33027

The results of the direct numerical integration of the Navier-Stokes equations are evaluated against experimental data for problem on a flow around bluff bodies in an unstable regime. Experiment records several stable medium states for flow past a body. Evolution of each of these states, after losing the stability, inevitably goes by periodic vortex shedding modes. Calculations based on the Navier-Stokes equations satisfactorily reproduced all observed stable medium states. They were, however, incapable of reproducing any of a vortex shedding modes recorded experimentally. The solutions to the classic hydrodynamics equations successfully reach the boundary of instability field. However, classic solutions are unable to cross this boundary. Most likely, the reason for this is the Navier-Stokes equations themselves. The classic hydrodynamics equations directly follow from the Boltzmann equation and naturally contain the error involved in the derivation of classic kinetic equation. Just the Boltzmann hypothesis, which closed kinetic equation, allowed us to con- struct classic hydrodynamics on only three lower principal hydrodynamic values. The use of the Boltzmann hypothesis excludes higher principal hydrodynamic values from the participation in the formation of classic hydrodynamics equations. The multimoment hydrodynamics equations are constructed using seven lower principal hydrodynamic values. The numerical integration of the multimoment hydrodynamics equations in the problem on flow around a sphere shows that the solutions to these equations cross the boundary and enter the instability field. The boundary crossing is accompanied by appearance of very uncommon acts in scenario of system evolution.

Status of the Streamer Mode in Gas Detectors  [PDF]
V. I. Razin
Modern Instrumentation (MI) , 2014, DOI: 10.4236/mi.2014.32002
This work shows the results of a streamer discharge mode studies in various gas detectors developed up-to-date. The results are based on a new experimental data from high-speed thin-gap gas detector application developments as well as on basic knowledge of multi-wire devices operations.
The M3Y Double Folding Dissipative Model in Agreement with Precise Fusion Cross Sections  [PDF]
I. I. Gontchar, M. V. Chushnyakova
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.45B001

Large numbers of precision fusion excitation functions were fitted in the literature using the nucleus-nucleus interaction potential having the Woods-Saxon shape. The diffuseness of this potential fusion ranges from 0.75 to 1.5 fm. This is much larger than the value of 0.65 fm required by the elastic scattering data. Trying to resolve this contradiction we develop the dissipative trajectory model based on the density-dependent M3Y NN-forces folded with the nuclear matter distribution. Resulting potential possesses the normal diffuseness about 0.65 fm. With this potential we reach the agreement with the data for 16O+208Pb, 28Si+208Pb, 32S+208Pb reactions within 5%.

FDTD Analysis of Millimeter Wave Binary Photon Sieve Fresnel Zone Plate  [PDF]
I. V. Minin, O. V. Minin
Open Journal of Antennas and Propagation (OJAPr) , 2013, DOI: 10.4236/ojapr.2013.13008

In the paper, we report about the possibilities to apply the photon sieve principle to binary diffractive lens in millimeter wave band. The FDTD simulation showing the idea of the photon sieve application to millimeter wave optics does not allow increasing the resolution power. The reason is the small number of holes in the FZP aperture. But such simulation results may be used as computational experiments of simple scale in millimeter wave allowing obtaining insight into physical systems which are characterized by nanometric objects, because the D/f and D/λ are almost the same.

Coordination Interaction between Rare Earth and/or Transition Metal Centers and Thiophene Series Oligomer Derivatives in Ultrathin Langmuir-Blodgett Films  [PDF]
H. V. Grushevskaya, I. V. Lipnevich, T. I. Orekhovskaya
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.412A3002

It has been shown by thermodynamic and electro-chemical methods that coordination interactions are involved in the process of incorporation of rare-earth elements and/or Fe into Langmuir monolayers of oligomer with alkyl fragment. A coordination mechanism, which is responsible for self-organization of octahedral Fe(II)-complexes of nano-cyclic ligands obtained from oligomer of thiophene pyrrole series derivatives in compressed Langmuir monolayers has been proposed. It has been established that a coordinational-polymeric hexagonal network of nano-cyclic ligands with metal centers is formed at the phase transition when compressing the Langmuir monolayers of thiophene pyrrole series oligomer with alkyl fragment on surface of subphase with rare-earth (Sm, Er, Ce) and/or Fe ions.

Sinonasal Undifferentiated Carcinoma—A Case Report  [PDF]
C. Aparna, I. V. Renuka
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2014, DOI: 10.4236/ijohns.2014.36068
Abstract: Sinonasal tumors with neuroendocrine differentiation are uncommon. They arise from schneiderian epithelium. The authors reported a case in a fifty-six years old female patient who came with complaints of headache and epistaxis. Differential diagnosis and review of literature are presented in detail. This case is presented in view of its rarity.
Production of Dissimilar Metals Materials by the Method of Solid-State Joining  [PDF]
B. V. Borts, I. M. Korotkova, O. O. Lopata, V. I. Sytin, V. I. Tkachenko, I. O. Vorobyov
Open Journal of Metal (OJMetal) , 2014, DOI: 10.4236/ojmetal.2014.42005
Mechanisms taking place while hot rolling in vacuum of dissimilar materials joined in solid phase are described. It is shown that at joining of materials in solid phase redistribution of atoms from one material into another occurs on the interface of joining. On the base of calculation and experimental results it is concluded that the ultimate strength of the interface of joint is always higher than the ultimate strength of less durable material. Pair zirconium-stainless steel SS (Type AISI 321) and carbon steel (Type C22E) those are used in nuclear power are investigated.
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