Optimizing the service life of drill-collar joints on the basis of fracture mechanics criteria

A method of calculation of the lifetime of fish-mouth collar joints has been proposed that is based on selecting a model and using the criteria of fracture mechanics. By this method it is possible to optimize the design parameters of collar joints as a function of the cyclic crack resistance of steels. It is shown that the lifetime of a collar joint with a fatigue crack can be predicted, and the size of the crack can be estimated for a certain operating time of the collar joint. The critical values of the length of a fatigue crack were calculated for various types and dimensions of collar joints, which is important in fixing the periodicity of crack detection operations.     

Langmuir films from antibodies based on amphiphilic polyelectrolytes

A technique for forming Langmuir films from antibodies based on an amphiphilic polyelectrolyte was developed. The physicochemical and immunochemical properties of the Langmuir films obtained were studied. The interaction of HBsAg with the films was found to be described by a model with one binding site, whereas that of HBsAg with antibodies adsorbed on a polystyrene plate, by a model with a positive cooperativity. The use of the novel Langmuir films from antibodies increases the sensitivity of the immunoenzyme assay.     

Internal friction and brittle-ductile transition in structural materials

The temperature dependences of internal friction (ultrasound decrement) and impact toughness of bcc metals (Fe-12Cr-W-V-Ta-B-C ferritic/martensitic steel, V-4Ti-4Cr vanadium-based alloy) have been studied in a temperature range from 100 to 300 K. The acoustic and mechanical characteristics exhibit correlated variation. The use of nondestructive acoustic techniques for the investigation of mechanisms of the brittle-ductile transition in metallic structural materials is experimentally justified.     

Parameters of hydraulic fracturing and disintegration of impervious rocks while preparing blocks for leaching

Conclusions 1. The maximum water injection pressure for hydrofracturing of Blyava ores was 12.1–12.9 MPa and for hydrodisintegration, 4.5–5.5 MPa. The calculated values of these pressures differ from the experimental ones by 20–25% and 25–36% respectively, which is satisfactory for natural-scale studies.2. The probability of hydrofracturing or hydrodisintegration of the mass depends a great deal on the distance between the packer and the borehole face. It has been demonstrated experimentally that hydrofracturing occurred at a distance of 0.1–0.6 m and only hydrodisintegration was noticed at a distance of 4–10.2 m. These data show that, all other conditions being equal, the packer (interpacker) spacing of the boreholes is of great importance for producing, in practice, some type of hydrodynamic impact on the rock mass.3. Water injection through boreholes into the ore body under conditions of hydrofracturing and hydrodisintegration showed the real possibility of establishing a hydrodynamic link between boreholes at distances of 5 m, 10 m, and greater.4. The technology and equipment developed by the Institute of Mining make it possible to prepare blocks of impervious ores for leaching by employing hydrofracturing and hydrodisintegration of rocks and creating in the block a borehole — slit — borehole system.5. As a result of suffosion of the ore, slime is released intensely from the drainage boreholes, which is typical for hydrofracturing and hydrodisintegration processes and for subsequent fluid injection under pressure. This may be used to augment the performance of the borehole — slit — borehole system.6. If conditions in the mining industry become favorable, it would be advisable to continue the operations, the essential features of which are elucidated in this paper.Translated from Fiziko-tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 100–105, September–October, 1996.     

Optical–microphysical properties of smoke haze from Siberian forest fires in summer 2012

A comprehensive experiment on the study of dynamics of optical and microphysical characteristics of submicron aerosols in the near-ground air layer was carried out in June–August of 2012 under conditions of extremely strong smoke haze originating from vast forest fires in Siberia. Variations of the spectral angular scattering coefficients and the degree of linear polarization in the visible wavelength range are studied, as well as the mass concentrations of dry fractions of aerosol and black carbon, relative content of black carbon (BC fraction), single scattering albedo, particle size distribution function, complex refractive index of the particulate matter, and parameter of condensation activity of aerosol. Peculiarities of differences between optical and microphysical characteristics of near-ground aerosol in smoke haze and under smokeless conditions are revealed. This study is important for validation of results of remote sensing of the composition of smoke haze and background atmosphere obtained from satellite data and sun photometric measurements at the Aerosol Robotic Network (AERONET).     

Study of flame structure for mixed solid fuels based on ammonium perchlorate and polybutadiene rubber

Results are presented for a numerical study of the flame structure for mixed solid fuels (MSF) based on ammonium perchlorate (APC) and APC + polybutadiene rubber (PBR). The combustion process is modelled using formal kinetics detailed on the basis of experimental data for combustion of a layered system with pressures of 0.26 atm. A simplified set of equations obtained from a complete Navier-Stokes set with the limiting transtition M O is used in order to construct a solution. Flame structure is studied for pressures of 40 atm, and values of thermal flows into the k-phase are obtained.Novosibirsk. Translated from Fizika Goreniya i Vzryva, Vol. 28, No. 4, pp. 59–65, July–August, 1992.