The influence of an input pulse on the formation of elution-curve symmetry

A numerical technique has been applied to study the influence of an input rectangular pulse of adsorbed substance on the formation of symmetry of an output elution curve within adsorption dynamics. Quantitative regularities of variation of time characteristics and the coefficient of elution-curve symmetry have been analyzed as a function of the variables of the numerical experiment. It is illustrated that the absolute difference of the corrected retention time is directly proportional to the duration of the input pulse with a coefficient of about 0.5. The elution-curve width measured at half-height varies slightly with an increase in the duration of the input pulse. It is illustrated that, in the range of relative length of adsorbent layer n from 2 to 3, the highest difference of symmetry coefficients of the elution curves, calculated with and without consideration for input pulse, can be observed. With an increase in n, the values of these symmetry coefficients asymptotically approach each other.     

Water chemistry of the system for cooling the electrical generator’ stator of the power unit at a thermal power station

Results from studies of the water chemistry used in the system for cooling the stator windings of alternators used in supercritical-pressure power units are presented, and a solution is suggested using which the standardized pH value of cooling water is maintained in the range 8.0–9.0. It is shown that addition of NaOH in the water cooling system when a drop of pH value occurs cannot fully satisfy the requirements of the operating circular due to low buffer properties of aqueous medium.     

Regularities of electrochemical dissolution of Cu 62 Zn alloy in chloride solutions

The pattern of the electrochemical ionization and passivation of Cu 62 Zn brass in chloride solutions with different compositions is studied. The electrochemical dissolution of Cu 62 Zn alloy is shown to be controlled by ionization of the copper component in the alloy. The dissolution selectivity of the brass Cu 62 Zn components and the modification of the surface of the alloy during electrochemical etching in chloride solutions are studied. The uniform electrochemical dissolution of α-brass in an acid medium was found to occur in the presence of chlorine ions and an Fe³⁺ oxidizing agent.     

Boundary layer separation in a laminar supersonic flow with energy supply source

The influence of electric discharge in a supersonic gas flow on the separation of a laminar boundary layer has been studied by numerical methods. The discharge is modeled by an energy supply source with preset intensity and configuration. It is established that the behavior of flows in the system with thermally insulated and isothermally cooled walls differs in a broad range of the heat source power. The possibility of controlling the boundary layer separation is demonstrated.     

Possibilities for raising the strength classification of ultralow-carbon steels exhibiting the BH-effect

One of the main trends in the development of materials for the body and other parts of automobiles is the greater use of high-strength steels, this being done in order to make the vehicle safer and lighter. The need for this change stems from the continual tightening of standards on tailpipe emissions. The largest metallurgical companies that presently make automobile sheet have been working with the main Russian automobile manufacturers to develop steels with improved commercial properties. This article presents results from studies conducted to optimize the technology used to make rolled products of high-strength, ultralow-carbon steels 01YuTB an 01YuPTB for the automotive industry. The optimized technology includes heat treatment in a continuous annealing furnace. Emphasis should be given to developing technical recommendations on how to optimally combine strength, stampability, and a guaranteed level of the BH-effect (BH₂ ≥ 30–40 N/mm²) in the production of automobile sheet of strength class K180, as well as BH steels of strength class K220 or higher. __________ Translated from Metallurg, No. 1, pp. 67–70, January, 2006.     

Water Chemistry and Chemistry Monitoring at Thermal and Nuclear Power Plants: Problems and Tasks (Based on Proceedings of Conferences)

In late May–early June 2017, two international science and technology conferences on problems of water chemistry and chemistry monitoring at thermal and nuclear power plants were held. The participants of both the first conference held at OAO VTI and the second conference that took place at NITI formulated the problems of the development of the regulatory base and implementation of promising water treatment technologies and outlined the ways of improving the water chemistry and chemistry monitoring at TPPs and NPPs for the near future. It was pointed out that the new amine-containing VTIAMIN agent developed by OAO VTI had been successfully tested on the power-generating units equipped with steam–gas plants to establish the minimum excess of the film-forming amine in the power-generating unit circuit that ensures the protection of the metal as 5–10 μg/dm³. A flow-injection technique for the analysis of trace concentrations of chlorides was proposed; the technique applied to the condensate of the 1000-MW steam turbine of the NPP power-generating unit yields the results comparable with the results obtained by the ion chromatography and the potentiometric method using the solver electrode. The participants of the conferences were demonstrated new Russian instruments to analyze the water media at the TPPs and NPPs, including the total organic carbon analyzer and the analyzer of mineral impurities in the condensate and feed water, that won a gold medal at the 45th International Exhibition of Inventions held in Geneva this April.     

Water-Chemistry and Its Utility Systems in CCP Power Units (Review)

Damageability of heat transfer surfaces of waste heat recovery steam generators (HRSG) of combined- cycle plants (CCP) can be reduced due to an increase in the quality of make-up and feed water, the use of phosphate-alkaline or amino compound water chemistry (WC), and improved chemical quality control of the heat carrier and make-up water preparation techniques. Temporary quality standards for the heat medium developed by the All-Russia Thermal Engineering institute (VTI) for CCP power units are presented in comparison with the IAPWS standards; preferences for the choice of a WC type for some power units commissioned in Russia in the first decade of this century are shown; and operational data on the quality of feed, boiler water, and steam for two large CCP-450 and CCP-425 power units are given. The state and prospects for the development of chemical-technological monitoring systems and CCP water treatment plants are noted. Estimability of some CCP diagnostic parameters by measuring specific electric conductivity and pH is shown. An extensive bibliography on this topic is given.     

Fuel Efficiency of Energy Sources in Heat Supply Systems

The imperfection of the approach to the fuel efficiency assessment of energy sources with the combined generation of electrical and thermal energy based on the specific fuel consumptions is shown; it is caused by the fact that the use of different methods for the separation of the total fuel consumption leads to ambiguous results. A simple and feasible technique for the comparative assessment of the system fuel efficiency of existing energy sources of different types is proposed. The technique is based on the combined use of two dimensionless criteria that are calculated based on the CHPP production activity parameters provided in the yearly reports. These criteria have a clear physical sense and do not require the separation of the CHPP total fuel expenses into components. Analytical calculation dependences that relate the values of the proposed criteria and the actual relative fuel conservation, which is calculated for each individual energy source with respect to the average fuel efficiency level that is actually achieved in the considered energy system, are presented. The proposed approach and the technique based on it make it possible to objectively assess and compare the actual fuel efficiencies of energy sources of different types in terms of relative fuel conservation. The practical importance of the developed technique is demonstrated for a specific case: the comparative analysis of the actual fuel efficiency at all heat supply sources of the Saratov Branch of PAO T Plus is performed based on the available reported data on the results of the production activity. The results are visualized in the form of a diagram representing the actual fuel efficiency of each CHPP (for each year) with respect to the average level achieved in this energy system during the operating period of 8 years. The presented materials can serve as a basis for the choice of rational ways to improve the CHPP fuel efficiency.