Science and Technology V.S. Vysotsky, Dr. Sc. (Engineering), Director of Superconducting Cable and Wire Division; V.V. Zubko, Cand. Sc. (Physics and Mathematics), Leading Researcher; S.M. Ryabov, Engineer; S.S. Fetisov, Cand. Sc. (Engineering), Deputy Division Director, Head of Laboratory; JSC VNIIKP Contact: firstname.lastname@example.org
Warming-up of HTSC tapes at currents exceeding critical value with nitrogen boiling hysteresis taken into account
Issues concerning overheating and stability of high temperature superconducting (HTSC) tapes at currents exceeding critical value are considered with actual parameters of liquid nitrogen boiling taken into account. The measurement results of voltage changes in actual liquid nitrogen cooled first- and second-generation HTSC tapes with direct current above critical are given. The HTSC tape thermal transition currents are presented. The authors offer a numerical model for the analysis of liquid nitrogen cooled HTSC tape behavior which helped to explain the different behavior of voltage in HTSC tapes. The numerical analysis shows that a substantial delay in bubble boiling activation is observed and boiling hysteresis phenomenon exists in liquid nitrogen in the course of heat transfer from first- and second-generation HTSC tapes to nitrogen in case of sudden voltage peaks. A comparative analysis of measured voltages in HTSC tapes is presented with numerical calculations.
Macroeconomic first- and second-generation HTSC tapes, thermal transition currents, stability.
M.A. Boev, Dr. Sc. (Engineering), Professor of the National Research University (MEI); Ei Maung, post-graduate of the National Research University (MEI)
Experimental investigations of mechanical properties of aerial optical cables for tropical climate
The results of long-term investigations of aerial optical cables under actual-use conditions are given. The cables were suspended horizontally on poles situated 50 and 120 meters apart from each other with different tensile loads applied so that to provide a sag of 0.75 and 1 %. In the course of testing the sag change occurring with all types of cables under investigation was monitored. Consideration was given to the applicability of earlier obtained patterns for mathematical description of the processes taking place under climatic and mechanical effects. General character of the equations involved for the statistical experimental data array was confirmed. The confidence boundaries for the parameters of these equations were set up and the correlation coefficients for the theoretical and experimental sag values for the cables under investigation were defined.
Cables, correlation, stretching, sag. R.E. Vasiliev, Deputy General Director of ZAO “Trade House of VNIIKP” Contact: email@example.com On-line measuring instrument is not a luxury! A way to save materials in cable production
The use of measurement systems for the on-line control of insulation thickness is described. It is shown that a substantial saving of insulating materials may be achieved due to the use of such systems on the old extrusion lines as well. The procedure of the on-line computation of material saving due to the optimization of insulation thickness is presented.
Yu. N. Loginov, Dr. Sc. (Engineering), Professor of “Pressure metal treatment” department of UrFU, Institute of Materials Science and Metallurgy; A.Yu. Postylyakov, post-graduate, Institute of Materials Science and Metallurgy Contact:firstname.lastname@example.org
Strained state of copper rod in the finishing pass of rolling
Analysis of the stress-strain state of copper rod in the finishing pass of rolling was made using finite-element simulation methods. Data on distribution of rate and extent of deformation, as well as pressure were obtained. The distribution patterns of design parameters are compared with the pattern of copper pickup on the groove of the roll in actual production, their identity is shown.
Copper, rod, stress, strain, forming, metal pickup.