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The paper presents the results of a corpus and Runet study of the imperfectivability and aspectual correlation of Russian prefixed verbs which are derivatives of verbs of motion (VoM), a group of Russian verb lexicon with special properties. Since this group is a subset of prefixed verbs, the imperfectivability of VoM is compared with the general ability of prefixed verbs to form imperfectives. Various theoretical models for describing the aspectual correlativeness of VoM derivatives, as well as morphological mechanisms of their formation, are also discussed. One of the issues under scrutiny is whether imperfectives of the type uchoditʹImprf are formed by adding a prefix to simplicia of the type choditʹImprf (assuming an Imprf ← Imprf prefixation model) or by suffixal imperfectivization from prefixed perfectives like ujtiPrf (involving, besides stem suppletion, the postulation of the stressed -i- as a new imperfectivization suffix). The paper argues for the first option. It also describes two types of aspectual correlation between prefixed VoM formed from simplicia that differ in (not)unidirectionality (idtiImprf– choditʹImprf, katitʹImprf– katatʹImprf): the model specific for the VoM: prijtiPrf– prichoditʹImprf, and the model of suffixal imperfectivization common with other prefixed verbs: dokatatʹPrf (and dokatitʹPrf) – dokat-yva-tʹImprf. [ABSTRACT FROM AUTHOR]

Hydrogen sensors, especially those operating at high temperatures, are essential tools for the emerging hydrogen economy. Monitoring hydrogen under process conditions to control the reactions for detecting confined species is crucial to the safe, widespread use and public acceptance of hydrogen as fuel. Hydrogen sensors must have a sensitivity ranging from traces of hydrogen (parts per million (ppm)) up to levels near the lower explosive limit (LEL = 4% H2 in the air) for safety reasons. Furthermore, they need to operate in cryogenic, ambient, and high-temperature environments. Herein, emphasis is given to hydrogen sensors based on solid oxide electrolytes (operating at high temperatures), in particular oxygen ion and proton conductors. The review is devoted to potentiometric, amperometric, and combined amperometric-potentiometric hydrogen sensors. Experimental results already reported in the international literature are presented and analyzed to reveal the configuration, principle of operation, and the applied solid electrolytes and electrodes of the high-temperature hydrogen sensors. Additionally, an amperometric sensor able to detect hydrogen and steam in atmospheric air through a two-stage procedure is presented and thoroughly discussed. The discussion reveals that high-temperature hydrogen sensors face different challenges in terms of the electrodes and solid electrolytes to be used, depending on the operating principle of each sensor type. [ABSTRACT FROM AUTHOR]

In response to Viktor Chrakovskij (2015; 2018), this paper contributes to the discussion about the theoretical model of Russian verbal aspect, i.e. whether it should be considered an inflectional or derivational (classifying) category. Inter alia, the regularity of secondary imperfectivation as a specific (and unique) morphological mechanism of aspectual derivation is verified based on the example of prefixal Russian verbs with the prefixes pro- and u- found in the Russian National Corpus and on the Russian-language Internet, using Yandex and Google search engines. In addition, I discuss the phenomenon of lexicalization (degrammaticalization) as a possible constraint on standard secondary imperfectivation of Russian verbs and offer arguments to refute the criticism of the inflectional model of Russian aspect. [ABSTRACT FROM AUTHOR]

The present review work is devoted to potentiometric sensors based on high-temperature proton-conducting ceramic materials. The technology developments and possible application of such sensors for the determination of concentration of hydrogen-containing components in gases, solids and melts are described and thoroughly discussed. A special attention is devoted to the analysis of experimental data already appeared in international literature and their adequacy to the basic operation principles. On the base of this analysis, the existing problems and future trends are revealed and discussed. [ABSTRACT FROM AUTHOR]

The rapid development of science, technology, and engineering in the 21st century has offered a remarkable rise in our living standards. However, at the same time, serious environmental issues have emerged, such as acid rain and the greenhouse effect, which are associated with the ever-increasing need for energy consumption, 85% of which comes from fossil fuels combustion. From this combustion process, except for energy, the main greenhouse gases-carbon dioxide and steam-are produced. Moreover, during industrial processes, many hazardous gases are emitted. For this reason, gas-detecting devices, such as electrochemical gas sensors able to analyze the composition of a target atmosphere in real time, are important for further improving our living quality. Such devices can help address environmental issues and inform us about the presence of dangerous gases. Furthermore, as non-renewable energy sources run out, there is a need for energy saving. By analyzing the composition of combustion emissions of automobiles or industries, combustion processes can be optimized. This review deals with electrochemical gas sensors based on solid oxide electrolytes, which are employed for the detection of hazardous gasses at high temperatures and aggressive environments. The fundamentals, the principle of operation, and the configuration of potentiometric, amperometric, combined (amperometric-potentiometric), and mixed-potential gas sensors are presented. Moreover, the results of previous studies on carbon oxides (COx), nitrogen oxides (NOx), hydrogen (H2), oxygen (O2), ammonia (NH3), and humidity (steam) electrochemical sensors are reported and discussed. Emphasis is given to sensors based on oxygen ion and proton-conducting electrolytes. [ABSTRACT FROM AUTHOR]

The present communication describes the results of the performance and the assessment of a sensor based on a solid oxide electrolyte with a composition of 0.9ZrO2 + 0.1Y2O3 (YSZ), equipped with a ceramic diffusion barrier for measuring the water vapor and hydrogen content in air. The possibility of determining the concentration of water vapor and hydrogen in the air is based on the measurement of the limiting current value. For the calculation of the steam and hydrogen concentration in ambient air, analytical expressions were obtained and applied, using the limiting current values measured in air with a standard oxygen concentration of 20.9 vol.% and in the analyzed air. A two-stage method for the determination of the hydrogen and steam amount in ambient air is proposed. It is stated that the sensor operates successfully at the temperature of 700 °C and can be applied for the continuous determination of steam or hydrogen concentrations in air. [ABSTRACT FROM AUTHOR]

Abstract: In the present work a theoretical model of a solid oxide electrolyzer based on an electrolyte having both oxygen ion and proton conductivity is considered. The main parameters of the electrolytic process and an electrolyzer (distribution of gas components, electromotive forces and current densities along the electrolyzer channel, average values of electromotive forces and current densities) were calculated depending on a proton transport number and mode of the reactants’ feeding (co- and counter-flow). The performed analysis demonstrates considerable influence of the mode of feeding on all parameters of the electrolyzer: operation under the counter-flow mode is preferable as regards the specific characteristics and uniformity of their distribution along the electrolyzer. It is shown that the electrolyser''s specific characteristics increase with the increase of the proton transport number. [Copyright &y& Elsevier]

Abstract In the present work, nitrogen-doped mesoporous carbon nanosheets (NMCNs) are prepared and extensively investigated for the oxygen reduction reaction. Initially, by using dual templates, viz. graphene oxide and a cationic surfactant, silica films (thickness: 1.0 nm) are synthesized and characterized using transmission electron microscope (TEM), nitrogen adsorption-desorption (N 2 ad/des) measurements, and small-angle X-ray diffraction (SA-XRD). Morphology and structure of silica evolve along with graphene oxide concentration, while the co-operative assembly and the final structure are determined by the electrostatic interaction between the dual templates. The effect of silica template on the resultant NMCNs is investigated physicochemically by photoelectron spectroscopy (XPS), TEM, N 2 ad/des and electrochemically by cyclic voltammetry (CV), and linear sweep voltammetry (LSV). NMCNs are featured of a high content of nitrogen dopant, high specific surface area (SSA) and ultrathin thickness (1.5 nm), favoring catalysis and facilitating the mass transport of the reactive species. From the electrochemical tests, it is confirmed that NMCNs yield a high oxygen reduction reaction (ORR) electrocatalytic activity in acid and alkaline environment; this activity is similar or even better as compared with the one measured over carbon supported platinum commercial catalyst (40 wt % Pt/C). Graphical abstract Image 1 Highlights • Nitrogen-doped mesoporous carbon nanosheets (NMCNs) are prepared by a nanocasting method. • NMCNs presents high content of nitrogen dopant, ultrathin thickness and high specific surface area. • Electrochemical tests confirm that NMCNs yield a high oxygen reduction reaction (ORR) activity. • ORR activity is comparable or even better when compared with that of commercial Pt/C catalyst. [ABSTRACT FROM AUTHOR]

In the present work, the steady-state current-overpotential characteristics of the Fe|BaCe 0.5 Zr 0.3 Y 0.08 Yb 0.08 Cu 0.04 O 3-δ |Fe interface as a function of the gas phase composition and temperature are investigated. To this purpose a BaCe 0.5 Zr 0.3 Y 0.08 Yb 0.08 Cu 0.04 O 3–δ dense ceramic material is successfully synthesized by solid state synthesis and sintered at 1400 °C. Then its crystal structure, ceramic and electrical properties are investigated. It is found that the ceramic has a high relative density (more than 90%) and acceptable proton conductivity (1.5 and 6.8 mS cm −1 at 500 and 900 °C, respectively). On the as prepared BaCe 0.5 Zr 0.3 Y 0.08 Yb 0.08 Cu 0.04 O 3–δ electrolyte disk, three thin Fe porous layers are deposited by painting on both sides (three electrode system), which is then immersed in a tubular single-chamber continuous electrochemical reactor. The polarization measurements are carried out in the temperature range between 500 and 700 °C and at three different H 2 /He wet (3% steam) compositions. The apparent anodic and cathodic charge transfer coefficients (Tafel region) are found to be: α a = α c = 0.8, while the apparent activation energy is calculated to be approximately 0.55 ± 0.05 eV. It is also found that by increasing the hydrogen concentration the current density increases, especially at higher temperature values. [ABSTRACT FROM AUTHOR]