Pulse current treatment effect on the strength of reinforcing steel and its weld joint under impact loading

We present results of static and impact tension tests of as-received reinforcing steel specimens, specimens with weld joints in their test portion, as well as specimens pretreated by high-density pulse current. As test results demonstrate, an increased strain rate enhances strength, and the pulse current treatment greatly influences the strength and plasticity of a defect-containing weld metal under static and impact tension.Peer reviewe

Evaluation of the residual stresses in the welded joint of the header with a connecting pipe of a steam generator after additional thermomechanical treatment

Translated from Problemy Prochnosti, No. 2, pp. 74 – 79, March – April, 2010We present the results of numerical evaluation of the possibility of application of additional thermomechanical treatment to the welded joints of the headers with connecting pipes of PGV-1000 steam generators from WWER-1000 reactor units of nuclear power plants with an aim to decrease the level of stresses formed after maintenance and in the process of subsequent operation. It is shown that this type of treatment is quite promising for extending the service life of the unit.Peer reviewe

Effect of pulsed electric current treatment on corrosion of structural metals

“The original publication is available at www.springerlink.com” Copyright Springer [Full text of this article is not available in the UHRA]Results of corrosion tests of structural metals previously treated using pulsed electric current of high density are presented. According to the data obtained, the treatment substantially affects corrosion of metals. In cases of HSLA steel and 5182 aluminum alloy, an increase of corrosion resistance occurs, whereas the same treatment causes a dramatic reduction of corrosion resistance of 5754 aluminum alloy.Peer reviewe

The effect of the pulse electric current treatment on residual stresses arising in grinding

Translated from Problemy Prochnosti, No. 6, pp. 44–50, November–December, 2009We show experimentally that the passing of a pulse electric current through a strip of stainless steel with a surface layer containing grinding-induced tensile stresses substantially reduces their level. In this case, the effect of treatment is not related to the macro-heating of the strip metalPeer reviewe

Pulse electric current effect on mechanical properties of titanium aluminide produced by the self-propagating high-temperature synthesis technique

Translated from Problemy Prochnosti, No. 6, pp. 81 – 92, November – December, 2012We present results of study on the effect of pulse electric current treatment on bending strength and hardness of intermetallic titanium aluminide produced by the self-propagating high-temperature synthesis technique. It is shown such treatment results in some increase in strength and plasticity of the intermetallide in comparison with the initial state, while its hardness decreases. The results of microstructural analysis show that reduction of the material brittleness after treatment is a consequence of current-induced change of thin structure of a material, redistribution of pores and reduction of the residual tensile stressesPeer reviewe

Redistribution of stresses in the header-PGV-1000 steam generator connector weldment under loading after thermal treatment

Additional heating of a thickened portion of the steam generator connector during postrepair thermal treatment of the header-connector weldment leads to a decrease in residual tensile stress levels. It is shown that during hydrostatic tests performed after thermal treatment inelastic strains on the inner connector surface are reduced, which inhances the cycle life of the weldmentPeer reviewe

Analysis of carbon stocks and fluxes of urban lawn ecosystems in moscow megapolis

Urbanization results in irreversible transformations of vegetation and soils. Urban lawn is an important part of urban ecosystems, providing several principal ecological functions, including participation in global carbon cycle. Carbon stocks and fluxes in urban lawns are diverse due to the different functional uses (residential, recreational areas, etc.), and different morphogenetic and physico-chemical properties of soil and their components. The research was focused on C stocks and fluxes in urban lawns to assess their function in regulating atmospheric air composition. Soil CO2 emission and CH4 fluxes (summarized for summer period); soil organic C (SOC); below and aboveground biomass were studied. Carbon emission by soil respiration and C sequestration in biomass were considered to estimate C balance