Processes in spark electric discharge in air, nitrogen and oxygen

The yield of redox reactions in aqueous solutions under the action of a remote spark discharge in the air, nitrogen and oxygen was studied. Mohr's salt and potassium permanganate were used as test substances. The direct and indirect effects of a source of active particles were compared. On direct exposure active species can immediately interact with the substance. By indirect action the source of active species directly affects only water. Immediately after treatment water was mixed with a solution of the test substance and the reactions of accumulated active species with the test substance began. When discharged in air medium, the oxidation and reduction reaction yields are approximately the same 5 - 6 1(100 эВ)-1 eV. Equal yields means that active species are firstly produced in water. When discharged in the nitrogen and oxygen medium, the oxidation yield is ∼15% lower, and the recovery yield is much lower. In this case, there is oxygen or nitrogen in the aqueous solution, so nitrogen oxides cannot be formed in water. So the contribution of products, produced in the discharge region is not more than 15% and that radiation plays a major role in initiating of chemical processes in liquid. © Published under licence by IOP Publishing Ltd

Comparison of Mechanisms for the Action of Cold Electric Discharge Plasma and Hot Pulsed Discharge Plasma Emission on Water Solutions

Cold electric discharge plasma can be in direct contact with the water solution being treated. Active species are generated directly in the discharge and penetrate into the solution through the gas-liquid interface. Hot plasma of pulsed electric discharge can remotely affect an object without causing any thermal damage to it, e.g., by means of irradiating it. The effect of light penetrating into the solution is fundamentally different from the effect of cold plasma which is in contact with the solution: cold plasma already contains all active species, while radiation does not contain any of them. The species are generated in water solution when radiation passes through it. It is shown that the penetration depth of radiation into distilled water can be considerable. The method for activated water production based on the effect of plasma radiation can be more advantageous than that based on its treatment with cold plasma. © 2021 Institute of Physics Publishing. All rights reserved.Project Center ITER; Science and Technology Center PLASMAIOFAN; State Research Center of Russian Federation TRINITI

Earliness and morphotypes of common wheat cultivars of Western and Eastern Siberia

The global and local climate changes determine the producing of highly-adaptive common (bread) wheat commercial cultivars of a new generation whose optimal earliness matches the climatic features of the territory where the cultivars are farmed. Principal component analysis involving our own and published data has been applied to investigate 98 commercial common wheat cultivars from Western and Eastern Siberia comparing their morphotypes; cultivar zoning time; length of the vegetation period; 1000-grain weight, and inheritance of spring growth habit. It demonstrated that the dominant Vrn gene polymorphism determining the spring growth habit of the Siberian cultivars was minimally polymorphic. In 75 % of the tested cultivars, the spring growth habit was controlled by digenic, namely dominant Vrn-A1 and Vrn-B1 genes. In 25 % of them (24 cultivars), spring growth habit is controlled by a single gene. In 19 and 5 of these cultivars spring growth habit is controlled by only one dominant gene, Vrn-B1 or Vrn-A1, respectively. In cv. Tulun 15, a trigenic control was identified. A conclusion about the optimality of the digenic control for the climatic conditions of both Western and Eastern Siberia has been confirmed. However, since none of the tested cultivars had the dominant Vrn-D1 gene typical of the regions of China and Central Asia bordering Siberia, it can be considered as an additional argument in favor of the European origin of Siberian common wheat cultivars. The revealed high frequency of the Vrn-B1c allele in the Western Siberian cultivars and the Vrn-B1a allele in the Eastern Siberian cultivars suggests their selectivity. The analysis also confirmed the dominance of red glume (ferrugineum, milturum) and awned spike (ferrugineum, erythrospermum) varieties in the Eastern Siberian cultivars, and white glume and awnedless spike (lutescens and albidum) ones in the Western Siberian cultivars. Small grain size cultivars are more typical of Eastern than Western Siberia. The retrospective analysis based on the cultivars’ zoning time included in the “State Register for Selection Achievements Admitted for Usage” brought us to the conclusion that the earliness/lateness of modern Siberian commercial cultivars was not regionally but rather zonally-associated (taiga, subtaiga, forest-steppe and steppe zones)

Plasma–liquid interactions: a review and roadmap

Plasma–liquid interactions represent a growing interdisciplinary area of research involving plasma science, fluid dynamics, heat and mass transfer, photolysis, multiphase chemistry and aerosol science. This review provides an assessment of the state-of-the-art of this multidisciplinary area and identifies the key research challenges. The developments in diagnostics, modeling and further extensions of cross section and reaction rate databases that are necessary to address these challenges are discussed. The review focusses on non-equilibrium plasmas

Spontaneous luminescence of hydrogen carbonate solution

The possibility of luminescence of freshly prepared doubly distilled water, settled doubly distilled water, and a bicarbonate solution has been studied. It has been found that the water settled in air can be a source of emission. The contribution of various factors including external background radiation to the luminescence of doubly distilled water has been examined. © Pleiades Publishing, Ltd., 2012

Formation of active species in spark discharge and their possible use

The chemical effects of self-sustained spark discharge with an energy per pulse of 5.9 × 10 -2 J, a pulse repetition frequency of 10 Hz, and a spark-gap breakdown voltage of 6 kV have been studied. The discharge generated a UV photon flux of (2.5 ± 0.3) × 1015 cm -2 s -1 with an energy density of (2 ± 0.3) × 10 -3 J cm -1 s -1 and the emission spectrum maximum at 220 nm. The action of the discharge on water samples leads to a decrease in pH and to buildup of oxidizing and reducing species. The formation of HO 2 radicals with an initial yield of (1.2 ± 0.3) × 10 -6 mol L -1 s -1 has been detected in the liquid. The initial yields of acid residues (increment in [H +]), oxidants, and reducing agents are (5.8 ± 1.6) × 10 -7, (3.3 ± 1) × 10 -6, and (4.2 ± 1) × 10 -7 mol equiv L -1s -1, respectively. The formation of NO - 3 and NH + 4 ions, nitrosamines, and organic compounds has been established. © Pleiades Publishing, Ltd., 2012