Standardization of the water heat carrier quality at Russian thermal power plants

The necessity of developing a new industry-specific standard of the heat carrier quality for the operating, newly commissioned, and prospective power-generating units of the thermal power plants is substantiated. The need of extending the scope of the automatic chemical monitoring and the possibility of indirect measurements of some basic standardized and diagnostic indices of the water chemistry using the specific conductance are shown. Investigations proved the possibility of automatic chemical monitoring of the phosphating of the drum boilers and quantitative control of potentially acidic impurities in the feed water in oncethrough boilers. The normative STO NP INVEL document developed at OAO VTI in 2009 is proposed as the basis for alterations and amendments. A new index, the total organic carbon, is introduced into this document. The standardized value of this index in the drum boiler feed water and steam is 100 μg/dm3. According to the above normative document, the scope of the chemical monitoring should be extended by measurements of the specific conductance of the direct and H-cation samples of both the feed and the boiler water. The content of chlorides should also be standardized. For the first time, normative restrictions are suggested on amine-containing water chemistry of the power-generating units with the combined cycle gas turbines. Flowcharts are proposed for pretreatment of the make-up water on the basis of low-mineralized natural waters with high organic substance contents, which reduces the oxidizability by 70–80%.     

Studying the Impulse Overloads in the Windings of a Station Service Voltage Transformer

One of the key factors determining the performance of a 110–500-kV station service voltage transformer (SSVT) is a compact insulation design that provides minimum winding sizes. Since SSVTs are new equipment that combine the operational features of a power transformer and the design features of a measuring voltage transformer, it is necessary to study the characteristic transient processes occurring under the impact of lightning-impulse test voltages and lightning and switching overloads in operation in order to ensure proper insulation design. The article presents the results of an experimental investigation of impulse transients in the windings of a full-scale mockup model of an active part of a 20-kV A SSVT with a rated voltage of 110 kV. The influence of grounding the low-voltage winding terminals on the maximum values and duration of impulse stresses on the longitudinal insulation of the high-voltage winding is revealed. It is shown that, unlike in the case of power transformers with disc windings, more significant effects on the insulation are produced when no load is applied on the low-voltage windings.     

Light‐Emitting Nanophotonic Designs Enabled by Ultrafast Laser Processing of Halide Perovskites

Nanophotonics based on resonant nanostructures and metasurfaces made of halide perovskites have become a prospective direction for efficient light manipulation at the subwavelength scale in advanced photonic designs. One of the main challenges in this field is the lack of large‐scale low‐cost technique for subwavelength perovskite structures fabrication preserving highly efficient luminescence. Here, unique properties of halide perovskites addressed to their extremely low thermal conductivity (lower than that of silica glass) and high defect tolerance to apply projection femtosecond laser lithography for nanofabrication with precise spatial control in all three dimensions preserving the material luminescence efficiency are employed. Namely, with CH₃NH₃PbI₃ perovskite highly ordered nanoholes and nanostripes of width as small as 250 nm, metasurfaces with periods less than 400 nm, and nanowire lasers as thin as 500 nm, corresponding to the state‐of‐the‐art in multistage expensive lithographical methods are created. Remarkable performance of the developed approach allows to demonstrate a number of advanced optical applications, including morphology‐controlled photoluminescence yield, structural coloring, optical‐ information encryption, and lasing.     

Acquired chemical defense in the lycaenid butterfly,Eumaeus atala

The lycaenid butterfly,Eumaeus atala, was found to contain cycasin, an azoxyglycoside, by thin-layer chromatography (TLC). Quantification of cycasin content in 10 individual freshly killed and frozen males and females, using capillary gas chromatography (GC), showed that cycasin contents of individual butterflies ranged from 0.21 to 0.51 mg (1.24–2.75% dry weight). A museum specimen ofE. atala of unknown age had undetectable amounts of cycasin by GC. GC showed that larval frass contained about 0.10% cycasin, which was not detectable by TLC. Cycasin in the host plant was not detectable by TLC but was detected by GC and found to be 0.02% dry weight. There was no macrozamin, another azoxyglycoside characteristic of many cycads, in the butterfly or plant. Feeding trials with a colony of the ant,Camponotus abdominalis floridanus, showed that both cycasin and the adult ofE. atala were deterrent to the ants.     

On technical requirements for Arc Suppression Reactors in the distribution circuit of 6–35 kV

Development of the technical requirements for arc suppression reactors (ASRs) used for the capacitive current compensation of the single-phase earth fault is a critical task. The corresponding GOST (State Standard) 19470–74 “Oil-Filled Arc Suppression Reactors. Technical Requirements” is no more valid; automatically controlled reactors (with adjustable spacing controlled by magnetic biasing) are the mainstream; and completely new reactor designs, with the capacitor adjustment in particular, have become available. The standard guide for the earth-fault current compensation [1], not taking into account new technologies, has become obsolete. This paper considers the current criteria for the ASR application in the 6- to 35-kV networks and proposes new ones. It is proposed to use the residual earth-fault current, but not the ASR detuning coefficient, as the major criterion for capacitive current compensation of the single-phase earth fault; in this case, new requirements for the ASR and the network conditions characterized by active phase-to-ground and harmonics content currents are specified taking into account the electrical safety regulations. The problem of capacitance asymmetry is considered absolutely and relatively, and it is shown that the use of ASRs controlled by magnetic biasing allows omitting the network balancing and limitation of the asymmetry voltage at the level of 0.75% of the phase voltage. It is proposed to take into account these recommendations during development of an earth-fault current compensation guide and general technical requirements for ASRs and automatic tuning systems.     

Experimental Investigation of Viscoelastic Characteristics of Rubber-Cord Composites Considering the Process of Their Self-Heating

Strength of Materials - The dissipative characteristics of rubber-cord composites under the action of cyclic load considering the features of their self-heating have been experimentally...     

Field experience with a new installation for countercurrent ion-exchange treatment of low-mineralized natural water with high content of organic impurities

Results obtained from examination of the working characteristics of filters are presented together with the filtering material analysis data that were obtained on a new high-output plant for ion-exchange treatment of natural water with high content of organic impurities. Stable operation of the plant is pointed out, and difficulties are indicated that arise from the fact that the water treatment system does not contain a unit for coagulation in a clarifier.