Movement stability analysis of a pipe string in a thixotropic fluid

Features of movement of a drill pipe string in a well filled with a thixotropic fluid are analyzed taking into account inertial and elastic forces of the rope system. It is shown that processes of fluid structure degradation can lead to nonstationary movement of the pipes. In this case periodic and chaotic auto-oscillations are excited in the system.Bashkir State University, Ufa, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 4, pp. 405–411, April, 1994.     

Ambient Pressure Superconductivity in к-(BEDT-TTF)2Cu[N(CN)2]Cl Single Crystals

Single crystals of the к-(BEDT-TTF)₂Cu[N(CN)₂]Cl radical cation salt possessing metallic properties and showing a superconducting transition with Tc = 11.5 K at ambient pressure were first prepared.     

Intercalation of C<Subscript>60</Subscript> fullerene crystals with calcium and barium via self-propagating high-temperature synthesis

We report a process for rapid intercalation of C₆₀ fullerene crystals using self-propagating high-temperature synthesis. The process has been used to intercalate C₆₀ fullerene crystals with calcium and barium. The superconducting transition temperatures of the intercalated fullerites have been measured, and the calcium-intercalated C₆₀ fullerene crystals have been characterized by X-ray diffraction.     

Mathematical model of solvent electrodesorption from capillary-porous materials under decreased pressure of the medium

A mathematical model of removal of adsorption-bound moisture from capillary-porous materials by decreasing the pressure in the presence of an internal heat source in the volume of the adsorbent is developed.     

Specific features of the formation of gas hydrates during the injection of a cold gas into a porous medium saturated with a gas and water

A mathematical model of the process of the formation of gas hydrates in a porous medium during the injection of a cold gas is presented. The cases where hydrate formation is limited by the kinetics of the process and heat and mass transfer in a porous medium are considered. The influence of the initial parameters of the porous medium and the intensity of the gas injection on the dynamics of the processes of hydrate formation is studied. The critical conditions that separate the different modes of hydrate formation are found.     

A technique for the rapid intercalation of alkali and alkaline-earth metals into crystalline C60 using self-propagating high temperature synthesis

The possibility of intercalation of alkali and alkaline-earth metals into C₆₀ fullerene crystals in 3-6 s using self-propagating high-temperature synthesis (SHS) has been demonstrated. Alkali (K, Rb) and alkali-earth (Ba, Ca) metals have been used as intercalants. Superconducting transition temperatures of the synthesized materials coincide with those of known intercalated compounds of C₆₀ fullerite obtained through conventional techniques. X-ray diffraction study of the SHS reaction product of C₆₀ with calcium is reported.     

Architectural monuments of Uzbekistan and the geologic-engineering medium

The problem of the failure of architectural monuments is examined, and means are proposed for its solution. Translated from Osnovaniya, Fundamentary i Mekhanika Gruntov, No. 4, pp. 22–25, July–August, 1997.