Improvement of automatic control systems of high-power turbines of PAO tubroatom for nuclear power plants

The main technical solutions applied by PAO Turboatom used as the compensatory measures at the increase of the period of nonstop operation of nuclear power plants' (NPP) turbines with VVER-1000 type reactors up to 18 months are (1) replacing the standard hydraulic speed controller with an electronic one, (2) introduction of overclocking protection, (3) modernization of units of stop-control valves of high pressures, (4) installation of locking dampers on the receiver tubes of turbines of the first and second modification, and (5) improving the quality of repairs by reviewing the requirements for their implementation. The introduction of complex diagnostics of a control system on the basis of automatic treatment of results of registration of working parameters of the turbine is allocated as a separate prospective direction. Using an electronic controller of speed makes it possible to simplify the procedure of its inclusion in work at the failure of an electro-hydraulic system of control and vice versa. The regimes of maintaining the turbine rotor speed, steam pressure on the outlet of turbine, and the positions of main servomotors were introduced into the functions of the electronic controller. An electronic controller of speed includes its own electro-hydraulic transducer, turbine rotor speed sensor, and sensors of the position of main servomotors. Into the functions of electro- hydraulic control system and electronic speed controller, the function of overclocking protection, which determines the formation of commands for stopping the turbine at the exceeding of both the defined level of rotation speed and the defined combination of achieved rotation speed and angular acceleration of rotor, was introduced. To simplify the correction of forces acting on the control valve cups, the design of the cups was changed, and it has the profiled inserts. The solutions proposed were implemented on K-1100-60/1500-2M turbines of Rostov NPP. From the composition of control system of already made turbines, the devices of speed switching of moving of control flaps for opening and hydraulic damper in the servomotors of regulating flaps were excluded; the fists of the control valves providing the increased valve stroke for opening and the construction of filters for regulation, electro-hydraulic converters, oil draining device, etc. was changed.     

Precision in Single-Coordinate Positioning of an Industrial Robot Manipulator

Russian Engineering Research - Many industrial robots are used in the automatic welding of large structures. However, more research is required on the monitoring of geometric defects in such...     

Phase Transitions in a Three-Dimensional Site-Diluted 5-State Potts Model

Journal of Superconductivity and Novel Magnetism - The phase transitions in the 5-state 3d site-diluted Potts model are investigated by means of the computer simulation methods. We address systems...     

Synthetic Compressor Oils for Production of Polyethylene

The possibility of manufacturing synthetic compressor oils for production of polyethylene is demonstrated. The propane–propylene fraction of catalytic gases or propylene from the EP–300 plant can be used as feedstock. After hydrogenation, fractions that totally satisfy the requirements for NKM–40 and NKM–200 mineral oils are separated from the oligomers. Wide–scale tests of these oils in compressors in the first and second levels of existing production of high-pressure polyethylene confirmed the possibility of using them to totally replace mineral oils.     

Hepatic apo E expression is required for remnant lipoprotein clearance in the absence of the low density lipoprotein receptor

According to the secretion-capture model of remnant lipoprotein clearance, apo E secreted by hepatocytes into the space of Disse serves to enrich the remnants with a ligand for receptor-mediated lipoprotein endocytosis. Current evidence supports a two-receptor model of lipoprotein removal, in which apo E-containing remnants bind either the low density lipoprotein receptor (LDLR) or the LDLR-related protein (LRP). Recently, we demonstrated that reconstitution of apo E(-/-) mice with apo E(+/+) marrow results in normalization of plasma lipoprotein levels, indicating that hepatic expression of apo E is not required for remnant clearance and calling into question the relevance of the secretion-capture mechanism. To dissect the relative contributions of LDLR and LRP to the cellular catabolism of remnant lipoproteins by the hepatocyte, bone marrow transplantation (BMT) was used to reconstitute macrophage expression of apo E in mice that were null for expression of both apo E and the LDLR. Reconstitution of macrophage apo E in apo E(-/-)/LDLR(-/-) mice had no effect on serum lipid and lipoprotein concentrations, although it produced plasma apo E levels up to 16-fold higher than in C57BL/6 controls. Immunocytochemistry of hepatic sections revealed abundant staining for apo E in the space of Disse, but no evidence of receptor-mediated endocytosis of remnant lipoproteins. Transient expression of human LDLR in the livers of apo E(+/+)--> apo E(-/-)/LDLR(-/-) mice by adenoviral gene transfer resulted in normalization of serum lipid levels and in the clearance of apo E-containing lipoproteins from the space of Disse. We conclude that whereas the LDLR efficiently clears remnant lipoproteins irrespective of the site of origin of apo E, endocytosis by the chylomicron remnant receptor (LRP) is absolutely dependent on hepatic expression of apo E. These data demonstrate in vivo the physiologic relevance of the apo E secretion-capture mechanism in the liver.     

Effect of rare-earth impurities on the photoluminescence of Ge<Subscript>2</Subscript>S<Subscript>3</Subscript> glass

The photoluminescence properties of Ge₂S₃ glass doped with rare-earth elements La, Ce, Gd have been studied in the temperature range of 4.2–300 K. It has been shown that these impurities do not form new levels responsible for emission. The variation in the principal parameters of the excitation and emission spectra with the concentration and nature of impurities has been estimated.     

Synthesis and studies of some metal-containing derivatives of [2-Hydroxy-3,5-di-(1-phenylethyl)phenyl]methylaminodiacetic acid

[2-Hydroxy-3,5-di-(1-phenylethyl)phenyl]methylaminodiacetic acid and its complexes with transition metals, Cu(II), Co(II), and Ni(II), were synthesized and studied. Protonated (MeHL) and deprotonated (MeL) complexes were prepared. It was found that of copper(II), cobalt(II), and nickel(II), [2-hydroxy-3,5-di-(1-phenylethyl)phenyl]methylaminodiacetates are effective as antiwear and antiscore agents.     

Oligomerization of propane-propylene fraction on a chloroaluminum complex

An attempt was made to use the industrial propane-propylene fraction (PPF) with ∼75% propylene to obtain its oligomers. The studies were conducted on a periodic pilot unit in a wide temperature and time range in solvent medium at different concentrations of the chloroaluminum complex. It was shown that without changing the composition of PPF, a line of products that satisfy the requirements for bases for different oils and __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 41–43, May–June, 2006.