Operation of sintering machines with a one-layer bed

Results are presented from commercial trials performed to examine the effect of the properties of the charge and the parameters of the charging equipment on the formation of the bed during the charging of sintering machines. To simultaneously increase the degree of segregation of the charge and alleviate its over-compaction during the charging operation, it will be necessary to improve the design of the charging system and search for new technical solutions to obtain the necessary charging parameters. __________ Translated from Metallurg, No. 6, pp. 33–37, June, 2006.     

Convective instability of directional crystallization in a forced flow: The role of brine channels in a mushy layer on nonlinear dynamics of binary systems

The linear analysis of morphological instability of the crystallization process with a mushy layer is carried out. The instability is caused by the influence of a forced oceanic flow leading to the formation of brine channels in the anisotropic and heterogeneous phase transition domain. Two instability criteria are found for the cases of non-turbulent and turbulent boundary conditions at the mushy layer–ocean interface. The theory under consideration shows that the instability domain will depend highly on the physical and operating parameters of the system.     

Modernizing the control system of the 2A656F11 milling and boring machine

The modernization of the digital control and display system for the 2A656F11 milling and boring machine is described.     

Kinase CDK2 in Mammalian Meiotic Prophase I: Screening for Hetero- and Homomorphic Sex Chromosomes

Cyclin-dependent kinases (CDKs) are crucial regulators of the eukaryotic cell cycle. The critical role of CDK2 in the progression of meiosis was demonstrated in a single mammalian species, the mouse. We used immunocytochemistry to study the localization of CDK2 during meiosis in seven rodent species that possess hetero- and homomorphic male sex chromosomes. To compare the distribution of CDK2 in XY and XX male sex chromosomes, we performed multi-round immunostaining of a number of marker proteins in meiotic chromosomes of the rat and subterranean mole voles. Antibodies to the following proteins were used: RAD51, a member of the double-stranded DNA break repair machinery; MLH1, a component of the DNA mismatch repair system; and SUN1, which is involved in the connection between the meiotic telomeres and nuclear envelope, alongside the synaptic protein SYCP3 and kinetochore marker CREST. Using an enhanced protocol, we were able to assess the distribution of as many as four separate proteins in the same meiotic cell. We showed that during prophase I, CDK2 localizes to telomeric and interstitial regions of autosomes in all species investigated (rat, vole, hamster, subterranean mole voles, and mole rats). In sex bivalents following synaptic specificity, the CDK2 signals were distributed in three different modes. In the XY bivalent in the rat and mole rat, we detected numerous CDK2 signals in asynaptic regions and a single CDK2 focus on synaptic segments, similar to the mouse sex chromosomes. In the mole voles, which have unique XX sex chromosomes in males, CDK2 signals were nevertheless distributed similarly to the rat XY sex chromosomes. In the vole, sex chromosomes did not synapse, but demonstrated CDK2 signals of varying intensity, similar to the rat X and Y chromosomes. In female mole voles, the XX bivalent had CDK2 pattern similar to autosomes of all species. In the hamster, CDK2 signals were revealed in telomeric regions in the short synaptic segment of the sex bivalent. We found that CDK2 signals colocalize with SUN1 and MLH1 signals in meiotic chromosomes in rats and mole voles, similar to the mouse. The difference in CDK2 manifestation at the prophase I sex chromosomes can be considered an example of the rapid chromosome evolution in mammals.     

Dynamic stability of band saw machines

The eigenfrequencies of the flexural–torsional vibrations of band saw blades and the limits of the instability regions are determined as a function of the tool parameters and the operating conditions. Analytical equations describing the dynamic stability regions of the plane form of the band saws are obtained.     

Effect of Shock Loading with Ultrasound on the Structure and Properties of the Metal of Welds and Products

Acoustic and x-ray diffraction studies were made of the effect of ultrasonic shock treatment on the stress state of a welded plate of steel St3sp and hard-faced rolling-mill rolls of steels 24KhNM1 and 12KhNM1. It was determined that treatment with ultrasonic pulses has a positive effet on the quality of metal products and their welds. __________ Translated from Metallurg, No. 6, pp. 63–65, June, 2005.