Experience gained from making the incineration of solid domestic wastes a factory standard at thermal power stations in Russia

Using the results of activities on developing and adjusting the processes pertinent to thermal reprocessing of solid domestic wastes (SDWs), that were carried out by VTI specialists along with GUP Ekotekhprom specialists in 1999–2005, we selected operating conditions under which the power installations run in compliance with the requirements (adopted both in Russia and in the EU countries) imposed on the incineration of SDWs and purification of flue gases. It is indicated that ways are currently being considered of increasing the parameters of steam generated at SDW-fired power stations from the existing p = 1.2?1.4 MPa and t _sup = 300?320°C to p = 4.0 MPa and t _sup = 400°C to make the generation of electricity at them more efficient. Experience gained in this field by the boiler manufacturing plants in Russia is analyzed.     

Experience Gained from Designing Exhaust Hoods of Large Steam Turbines Using Computational Fluid Dynamics Techniques

Experience gained from designing exhaust hoods for modernized versions of K-175/180-12.8 and K-330-23.5-1 steam turbines is presented. The hood flow path is optimized based on the results of analyzing equilibrium wet steam 3D flow fields calculated using up-to-date computation fluid dynamics techniques. The mathematical model constructed on the basis of Reynolds-averaged Navier–Stokes equations is validated by comparing the calculated kinetic energy loss with the published data on full-scale experiments for the hood used in the K-160-130 turbine produced by the Kharkiv Turbine-Generator Works. Test calculations were carried out for four turbine operation modes. The obtained results from validating the model with the K-160-130 turbine hood taken as an example were found to be equally positive with the results of the previously performed calculations of flow pattern in the K-300-240 turbine hood. It is shown that the calculated coefficients of total losses in the K-160-130 turbine hood differ from the full-scale test data by no more than 5%. As a result of optimizing the K-175/180-12.8 turbine hood flow path, the total loss coefficient has been decreased from 1.50 for the initial design to 1.05 for the best of the modification versions. The optimized hood is almost completely free from supersonic flow areas, and the flow through it has become essentially more uniform both inside the hood and at its outlet. In the modified version of the K-330-23.5-1 turbine hood, the total loss coefficient has been decreased by more than a factor of 2: from 2.3 in the hood initial design to a value of 1.1 calculated for the hood final design version and sizes adopted for developing the detailed design. Cardinally better performance of both the hoods with respect to their initial designs was achieved as a result of multicase calculations, during which the flow path geometrical characteristics were sequentially varied, including options involving its maximally possible expansion and removal of the guiding plates producing an adverse effect.     

Interaction of Gd(III) MRI contrast agents with membranes: a review of recent EPR studies

Rational development of new selective paramagnetic contrast agents (PCAs) requires a detailed understanding of their interactions with biological macromolecules. This report shows how some of these interactions can be studied with electron paramagnetic resonance (EPR) through examples of Gd³⁺ complexes interactions with model phospholipid membranes. It is shown that the spin label EPR method can be used to detect: (i) presence and possible location of lipophilic contrast agents in the model membranes, (ii) changes and distortions in membrane organization upon interaction with the PCAs, and (iii) changes in the local polarity of the bilayer and its phase behavior due to addition of Gd³⁺ complexes. This work demonstrates that interaction of Gd³⁺ complexes with phospholipid bilayers can be observed directly from changes in their continuous wave (CW) EPR spectra obtained at frequencies higher than X-band (9.5 GHz), where signals arising from aqueous and lipid-bound Gd³⁺ complexes become resolved. Analysis of frequency dependence of the effectiveg-factors of the EPR signal provides estimates of zero-field splitting (ZFS) parameter for these complexes at physiological conditions and information on how this parameter is affected by interaction with lipids. Multifrequency EPR experiments at high magnetic fields are also useful in providing data on the frequency dispersion of electronic relaxation caused mainly by a modulation of the electron-electron dipolar interaction (ZFS) of these high spin ions.     

Electromagnetic gate-inductor electric drives with open-loop control systems

A simplified transducer-free realization of electromagnetic gate-inductor electric drives with openloop control systems is proposed with prospective applications for the majority of rotary-, linear-, and alternatemotion-type industrial mechanisms. A functional scheme of the control system for the electric drive under consideration is given. A simplified calculation of the basic parameters of the rotary motion electric drive is presented. The advantages of reducer-free electric drive constructions are shown.     

Gas-Hydrate Formation and Phase Transformations of Adsorbed Water in Kuznetsk Basin Coal

Among the properties of coal that must be studied in order to optimize its preparation for coke production and deep processing are the interactions of adsorbed materials—in particular, water, methane, and carbon dioxide—with its surface. An important aspect of these interactions is phase transformation of the adsorbed materials in the internal porous structure to form hydrate or ordinary ice. In regular coal, a hydrate of carbon dioxide is formed at a CO₂ pressure of 2–4 MPa and temperatures below 10°C, when the moisture content of the coal exceeds the threshold value. However, at the same moisture content, no ice is formed at temperatures between +13°C and –13°C, while decomposition of the hydrate is observed close to the equilibrium curve. For gases that do not form hydrates (helium, nitrogen, argon) in the given temperature and pressure ranges, increasing the pressure to 12 MPa has no influence on the solidification of sorbed water and ice formation.     

The choice of power electron switches for converters in electroenergetics

A comparison of different power electron switches for power electron converters is presented. The estimation method of steady and dynamic power loss in the switches is also described.     

Efficiency of classical molecular dynamics algorithms on supercomputers

High performance computing hardware is developed faster than the algorithms for fundamental mathematical models such as classical molecular dynamics are adapted. A wide variety of choice makes it necessary to determine clear criteria based on the computational efficiency of a specific algorithm on a particular hardware. The LINPACK benchmark can no longer serve this purpose. In this paper, we analyze the solution time–peak performance metric based on practical considerations. In this metric, we compare different hardware (both current and obsolete) based on the example of the LAMMPS benchmark, which is widely used for atomistic simulations. It is shown that the considered metric can be used for unambiguous comparison of different combinations of CPUs, accelerators, and interconnection.