Automated control of the velocity of in-tube diagnostic tools for main gas pipelines: I. Development,design, and operating principle of a bypass device

The study considers the development, design, and operating principle of a bypass device integrated into existing in-tube diagnostic tools. The bypass device is designed for automated control of the velocity of in-tube pig flaw detectors in main gas pipelines. Equipment of in-tube diagnostic tools with an automated-control system for the velocity provides performance of in-tube inspection without decreasing gas transportation. This facilitates the flaw detection of main pipelines substantially and makes a dispatcher of a gas-compressor station free of controlling the velocity of passage of in-tube diagnostic tools. The results of assembling a bypass device used for automated control of the velocity of in-tube diagnostic tools for main gas pipelines are considered. Arrangement of the bypass device in existing diagnostic tools for nondestructive testing is based on the experience of development, design, and exploitation of pig flaw detectors, which make it possible to locate the elements of the bypass device without any substantial restructuring of the pig flaw detectors.     

Conductivity of Proton Electrolytes Based on Cesium Hydrogen Sulfate Phosphate

The conductivity and thermal behavior of cesium hydrogen sulfate phosphate are studied. New composite proton electrolytes (1 – x)Cs₃(HSO₄)₂(H₂PO₄)–xSiO₂ with a high conductivity in the range 60–200°C are prepared, and their transport properties are studied in a broad composition range (x = 0.3–0.95). Their conductivity exceeds that of CsHSO₄–SiO₂ composites and depends strongly on composition: it reaches a maximum at x = 0.7 (22 vol % SiO₂) and drops at higher silica contents on account of percolation disruption. It is shown by differential scanning calorimetry and x-ray diffraction analysis that the introduction of fine-particle silica stabilizes the high-conductivity, disordered state of the mixed salt on the surface of the silica particles.     

Unsteady combustion processes in a channel with gas stream swirling and its termination

Results of numerical simulation of the flow and combustion of a pre-mixed gas mixture in a cylindrical channel at sudden swirliing of the flow and its sudden termination are considered. The calculations conducted show that the flow swirling allows flame localization in a given volume of the combustion chamber and is an effective method for combustion control. Translated fromFizika Goreniya i Vzryva, Vol. 35, No. 4, pp. 33–40, July–August 1999.     

Investigation of chemical transformations of thiophenylglycoside of muramyl dipeptide on the fumed silica surface using TPD-MS,FTIR spectroscopy and ES IT MS

In this study, chemical transformations of benzyl ester of О-(phenyl-2-acetamido-2,3-dideoxy-1-thio-β-d-glucopyranoside-3-yl)-d-lactoyl-l-alanyl-d-isoglutamine (SPhMDPOBn) on the fumed silica surface were examined, and the surface complex structure was characterized by temperature-programmed desorption mass spectrometry (TPD-MS), infrared spectroscopy (FTIR) and electrospray ion trap mass spectrometry (ES IT MS). Stages of pyrolysis of SPhMDPOBn in pristine state and on the silica surface have been determined. Probably, hydrogen-bonded complex forms between silanol surface groups and the C = O group of the acetamide moiety NH-(CH₃)-C = O…H-O-Si≡. The thermal transformations of such hydrogen-bonded complex result in pyrolysis of SPhMDPOBn immobilized on the silica surface under TPD-MS conditions. The shifts ∆ν of amide I band (measured from 1,626 to 1,639 cm^−l for SPhMDPOBn in pristine state) of 33 and 35 cm^−l which occurred when SPhMDPOBn was immobilized on the silica surface may be caused by a weakening of the intramolecular hydrogen bonding of the SPhMDPOBn because the interaction with the silica surface as hydrogen bond with silanol groups is weaker than that in associates.     

A unified methodological approach to calculation analysis of the stages of nucleation and growth of low-cycle fatigue cracks

A. A. Blagonravov Institute of Engineering, Russian Academy of Sciences, Moscow. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 29, No. 2, pp. 7–12, March–April, 1993.     

Determination of the Thickness of the Glass Band in a Tank with Melted Tin at Different Stages of Molding

A method for determination of the geometric parameters of the glass band in a tank with tin melt is developed, and the effect of molding conditions on these parameters is investigated. Data providing a more accurate understanding of the processes in different stages of molding are obtained and systematized. It is established that an equilibrium glass band thickness is formed under the effect of the edge-restricting machines and not in free spreading of the melt in the initial stage of molding, as was earlier believed.     

Heat transfer and combustion for a spiral flow in an ideal-displacement reactor

Hydrodynamic equations have been used with a numerical method to construct the temperature and concentration patterns for a reacting gas. Heat transfer in an ideal-displacement reactor is examined along with the structure of the reaction zone for various values of the spiral flow parameters.Translated from Inzhenerno-fizicheskii Zhurnal, No. 2, pp. 217–225, February, 1991.     

Separable functions in load separation for the ηpl and ηpl CMOD plastic factors estimation

The objective of this paper is to develop the load separation method for evaluating the _pl and _pl ^CMOD plastic factors used in the J estimation approach based on load versus displacement records. Appropriate forms for the geometry and deformation functions have been suggested from the EPRI Handbook solutions to produce the separable form for the load. The obtained functions are applied to evaluate the _pl and _pl ^CMOD plastic factors for center cracked tension specimen. The present load separation method gave results which are somewhat different from the estimated values of _pl given in the literature. For shallow cracks, the _pl and ^CMOD _pl plastic factors show considerable variation with crack size and the strain hardening exponent. For a deeply cracked CCT specimen, the ^CMOD _pl factor tends to the _pl factor and equals approximately unity. Abbreviations: CCT – center cracked specimen; CMOD – Crack Mouth Opening Displacement; EPRI – Electric Power Research Institute; FEM – Finite Element Method; LLD – Load Line Displacement.