Adjustment and operation of the continuous concrete plant at the construction site of the Sayano-Shushenskoe hydroelectric station

Power Technology and Engineering -     

Setting up the water chemistry for thermal water treatment

Results are presented from the development and setting up of water-chemistry conditions for a thermal water treatment process that allows saline effluents from a boiler house to be eliminated. Peculiarities of reducing scale formation in the evaporator through the use of chalk primer and type PAF-13A antiscale agent are discussed. The results of industrial tests of a thermal water treatment plant are presented that confirm the possibility of producing makeup water for heating networks and steam boilers.     

Use of 140-ton ladles to transport liquid pig iron

At the end of 2003, the Chelyabinsk Metallurgical Combine began to use 140-ton ladles instead of 100-ton ladles to transport liquid pig iron to its oxygen converter shop. The larger ladles comprised roughly 55% of the ladle stock in 2006 and transported 65% of the pig iron to the shop. Use of the 140-ton ladles has markedly improved adherence to the tapping schedule and sharply reduced the number of inadequately processed blast-furnace heats. It has also increased the temperature of the pig iron in the converter shop due to the smaller heat losses in the larger ladles.     

Use of Large-Area Photodiodes for Improving the Characteristics of an Electromagnetic Calorimeter Based on Lead Tungstate Crystals

It is shown that an increase in the area of photodetectors allows the PHOS electromagnetic calorimeter of the ALICE experiment to operate at room temperature with better spectrometric characteristics. The linearity of the calorimeter response has been investigated in the 1–110 GeV energy range using both Hamamatsu S8664-1010 avalanche photodiodes with a large area (10 × 10 mm²) and arrays of MPPC Hamamatsu S12572-015C silicon photomultipliers with a sensitive area of 6 × 6 mm². The calorimeter based on avalanche photodiodes is linear in the energy range under investigation compared to a calorimeter composed of silicon-photomultiplier arrays.     

The use of silicon photomultipliers for improving the time resolution of an electromagnetic calorimeter based on lead tungstate crystals

The use of S12572 MPPC silicon photomultipliers (Hamamatsu) for improving the timing characteristics of the PHOS electromagnetic calorimeter in the ALICE experiment at CERN is described. It is shown that by introducing an additional photodetector, that is, a silicon photomultiplier, it is possible, without worsening the energy resolution, to significantly improve the time resolution of the PHOS spectrometer from the current values of 3–4 ns to 150–200 ps.     

Thermodynamic Properties and Decomposition of Lithium Hexafluoroarsenate, LiAsF6

The heat capacity of lithium hexafluoroarsenate is determined in the temperature range 50–750 K by adiabatic and differential scanning calorimetry techniques. The thermodynamic properties of LiAsF₆ under standard conditions are evaluated: C _p ⁰(298.15 K) = 162.5 ± 0.3 J/(K mol), S ⁰(298.15 K) = 173.4 ± 0.4 J/(K mol), ⁰(298.15 K) = 81.69 ± 0.20 J/(K mol), and H ⁰(298.15 K) – H ⁰(0) = 27340 ± 60 J/mol. The C _p(T) curve is found to contain a lambda-type anomaly with a peak at 535.0 ± 0.5 K, which is due to the structural transformation from the low-temperature, rhombohedral phase to the high-temperature, cubic phase. The enthalpy and entropy of this transformation are 5.29 ± 0.27 kJ/mol and 10.30 ± 0.53 J/(K mol), respectively. The thermal decomposition of LiAsF₆ is studied. It is found that LiAsF₆ decomposes in the range 715–820 K. The heat of decomposition, determined in the range 765–820 K using a sealed crucible and equal to the internal energy change U _r(T), is 31.64 ± 0.08 kJ/mol.     

Portable Planar DMA: Development and Tests

A novel high-resolution planar and portable differential mobility analyzer (DMA) has been designed and built (Nano-ID® PMC500, Naneum, Canterbury, UK). Finite element multi-physics numerical modeling was employed to optimize the geometry of the DMA and to find a regime for high resolution within the confines of a portable instrument. The numerical approach for solving the Navier–Stokes equation was verified by comparison of calculated data to experimental values. The PMC500 was calibrated and tested with different monodisperse aerosol challenges. The PMC500 portable DMA is shown to have good sizing accuracy and resolution, similar in performance to commercially available desktop instruments.

Copyright 2014 American Association for Aerosol Research     

Computational and analytical studies of the processes in electromagnetic bearings in adjustment of the rotor of a turbine engine

The stability of an electromagnetic bearing control system-rotor system with a nonlinear dependence of the magnetic force on the control current is studied by analytical and experimental methods. The possibility of implementing an electromagnetic suspension of a rotor in the absence of currents of initial magnetic biasing is demonstrated. The advantages and disadvantages of such an implementation of the control system are determined. A program for calculating the time evolution of the motion of a rotor on electromagnetic bearings is developed and implemented in practice. A technique for verifying the program under conditions where initial data for calculations are not known accurately is proposed.     

Modification and functional properties of detonation nanodiamond

Abstract

Original termination of the detonation nanodiamond (DND) was changed by active chemical media interaction. Oxidation in boiling chloric acid, by hydrogen and chlorination by carbon tetrachloride vapor was applied. FTIR, TGA, and photoluminescence techniques revealed the DND functional termination changing. At hydrogenation treatment monofunctionally of the surface demonstrated. The totality of presented results demonstrates the possibility of substantial and controlled changes in the DND functional properties, for their subsequent use in the self-organization processes, at nanocomposites preparation and for other aims.