Investigation of the growth rate of cracks in shells made of the alloy Zr-1%Nb under conditions of iodine corrosion cracking under stress

Conclusions A method has been developed to determine the growth rate of a crack under conditions of iodine corrosion cracking of Zr-1%Nb claddings under stress. The dependence of the growth rate a crack on the stress-intensity factor in Zr-1%Nb claddings was determined and the threshold stress-intensity factor, equal to 4.8 MPa·m^1/2, was determined. Main Science Center of the Russian Federation — A. A. Bochvar All-Russia Scientific-Research Institute of Standardization in Machine Engineering. Translated from Atomnaya énergiya, Vol. 80, No. 2, pp. 87–91, February, 1996.     

Strength and deformation properties of compositions with plasma-sprayed coatings

Results, which make it possible to compare the strength properties of the group of compositions investigated with plasma-sprayed coatings, are obtained. It is established that the deformability characteristic _cr ^c correlates better with strength characteristics as compared with the universally adopted deformability characteristic _cr ^b . It is demonstrated that based on the set of parameters determined, compositions with a thin dysprosium oxide coating and compositions with a thick yttrium oxide exhibit the best mechanical characteristics of the coatings compared.Translated from Problemy Prochnosti, No. 6, pp. 57–60, November–December, 1966.     

Effect of Gene Silencing of Translation Initiation Factors eIF(iso)4G and eIF(iso)4E on Sour Cherry Rootstock Resistance to Sharka Disease

Sharka disease, caused by the Plum pox virus (PPV), is one of the most harmful, quarantine viral diseases that affect stone fruit crops. The absence of natural resistance to the virus in stone fruits has become a decisive factor for the use of genetic transformation methods to obtain stable forms. The eIF(iso)4G and eIF(iso)4E genes encode translation initiation factors used in the PPV life cycle. In the presented study, the effect of silencing these genes using the RNA interference method on the resistance of sour cherry rootstock 146-2 plants (Prunus pumila L. x Prunus tomentosa Thunb) to the sharka disease was studied. Two vectors have been created for the genetic transformation of plants, with self-complementary sequences of the eIF(iso)4G and eIF(iso)4E gene fragments. The hairpin expression cassette contains a strong promoter of the peach ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) gene, as well as an intron and terminator of the same gene. We used the pMF1 vector containing recombinase R and a codA-nptII gene which makes it possible to obtain intragenic marker-free plants. A successful genetic transformation was carried out by the AGL0 strain of A. tumefaciens. Whole leaves of shoots cultivated in vitro were used as a source of explants. Eight independent transgenic lines of rootstock 146-2 were obtained in experiments (sixlines with a hairpin to the eIF(iso)4G gene and two lines with a hairpin to the eIF(iso)4E gene). Their status was confirmed by the PCR and Southern blotting. The obtained plants were acclimatized in a greenhouse. The silencing of the eIF(iso)4G and eIF(iso)4E genes in transgenic plants was confirmed by the quantitative PCR. The presence of specific small interfering (si) RNAs was confirmed by the method of Northern blotting. Plants of all transgenic rootstock lines were infected with PPV by the method of grafting with infected buds. Resistance to the PPV infection of the obtained transgenic plants was carried out by using an enzyme immunoassay. The ELISA results showed that silencing the eIF(iso)4G gene did not lead to increased resistance while silencing the eIF(iso)4E factor gene led to increased resistance to the PPV, and the one line’s plants showed no signs of infection for two years after infecting. The work demonstrates a (promising) approach in which the creation of stone cultures resistant to the plum pox virus can be achieved by suppressing the genes of translation initiation factors in clonal rootstocks.     

Feasibility of Diagnosing Corrosion Cracking in Main Pipelines

With a view to assessing various diagnostic techniques for corrosion and stress-corrosion aws, results of an in-pipe inspection of a pipeline section have been analyzed. The statistical data are presented in the form of plots of aw dimensions versus their positions over the length of the inspected part of the pipeline and also over the pipe cross section. In order to identify common characteristics of corrosion and stress-corrosion aws, results of the in-pipe inspection of the pipeline were analyzed, and it turned out that there are essential differences in most parameters of the corrosion and stress-corrosion aws. The analysis took into account geographical features of the pipeline and protecting potentials in the inspected parts of the pipeline. The most essential differences between the corrosion and stress-corrosion cracking are in the distributions of the aws over the inspected pipeline division. The pipeline sections with higher densities of stress-corrosion aws contained smaller numbers of corrosion aws, and vice versa. The ultimate aim of the reported research was to compare the opportunities offered by direct and indirect diagnostic techniques designed to detect corrosion cracking in main pipelines.     

Production of auto-body dual-phase steel with single-step cooling on the output conveyer of the 2000 continuous broad-strip mill at OAO NLMK

The goal is to produce hot-rolled dual-phase steel of strength class DP 450–600 at OAO Novolipetskii Metallurgicheskii Kombinat (NLMK). The steel’s final structure and properties is greatly affected by single-stage strip cooling on the output roller conveyer of the 2000 continuous broad-strip mill. The influence of the hot-rolling parameters on the structure and mechanical properties of the hot-rolled SPRC440R steel from which cold-rolled dual-phase steel is produced at OAO NLMK is studied in the laboratory. The temperatures and rates for accelerated cooling on the output roller conveyer of the 2000 continuous broad-strip mill at OAO NLMK are calculated by means of a mathematical model. The laboratory data and simulation results are used in developing trial conditions for industrial rolling. Recommendations are made regarding the production of hot-rolled dual-phase steel corresponding to strength class DP 450–600.