Superlative Photoelectrochemical Properties of 3D MgCr- LDH Nanoflowers influencing towards Photoinduced Water Splitting Reactions

Layered double hydroxides (LDHs) are competent photocatalysts for water splitting reactions, vital to produce solar fuels, but their restricted available reactive sites, slow mass and charge transfer, are yet remain a challenge. To surmount these lacunas, Nanoflowers-like three-dimensional (3D) open structure of MgCr-LDH have been designed in a substrate-free path by one-step formamide assisted hydrothermal treatment followed by visible light irradiation and utilized as efficient photocatalysts for the H2 and O2 production. The structural, morphological, optical and photoelectrochemical (PEC) properties of the MgCr-LDH nanoflowers were extensively examined, by various physico-chemical characterization techniques. Moreover, the well-designed 3D MgCr-LDH nanoflowers with open structure were formed by a stacking of numerous 2D nanosheets, which inherently triggered with magnificent PEC properties, including high current density of 6.9 mA/cm2, smallest arc of the Nyquist plot (59.1 Ω cm−2) with photostability of 6000 s thereby enhancing the photocatalytic water splitting activity along. Moreover such a perfectly self-stacked 2D nanosheet in 3D MgCr-LDH possess defect sites as enriched 50% oxygen vacancy resulting a good contact surface within the structure for effective light absorption and easy electron and hole separation, facilitates the adsorption of protons and intermediate of water oxidation. Further, the doped Cr3+ pull up electrons from water oxidation intermediates, thereby displaying superior photocatalytic H2 and O2 production activity of 1315 µmol/h and 579 µmol/h, respectively. Favorable oxygen vacancy type defect surface with Cr3+ dopant in MgCr-LDH triggers significant PEC properties, which influences the easy charge transfer and separation mechanism and robustly enhance the photocatalytic performance of the nanoflower.

DEVELOPMENT OF LOW-MELTING GLASSCERAMIC BONDS FOR HIGH RESOURCE DIAMOND-ABRASIVE TOOLS

Research is aimed at creating high-resource diamond-abrasive tools with a large-pore structure of the working layer, the use of which reduces the occurrence of grinding defects when processing materials sensitive to overheating. The formation of an open structure of the working layer ensures effective chip removal, which excludes a decrease in the сutting ability of the tool due to contamination with grinding sludge and creates favorable conditions for intensifying the processing of materials when using high-speed cutting modes. As part of the research, low-melting glass-ceramic binders for diamond-abrasive tools have been developed, which make it possible to increase the tool service life due to the prevention of diamond grains premature destruction and the creation of a large-pore open structure of the working layer. Using a set of calculated data about the main characteristics of glass compositions by factor planning means, the dependences «composition - properties» were determined and the area of optimal compositions of glass-ceramic bonds was established, which ensure sintering of a diamond-containing composite at a temperature of 550–650 °C. The efficiency of the use of alumino-silicate microspheres of technogenic origin as a structure-forming filler providing the formation of a large-pore structure is shown. The features of the chemical and phase composition of the technogenic spheres recovered from the fly ash of the Krivoy Rog TPP have been determined. It has been established that when the diamond-bearing layer of the tool is sintered in the shell of the ash spheres, crystalline new formations with high hardness (hercynite, mullite, maghemite, spinel) are formed. Using ash spheres and developed low-melting binders, which include up to 30 mass. % of glass waste, the laboratory samples of diamond-containing composites with open porosity of 45-50% were made. Studies of their microstructure and morphological features made it possible to determine the pore size (130-200 μm) and establish that during grinding, partial destruction of ash spheres occurs with the formation of additional cutting elements, which increases the tool cutting ability. The research results indicate the advisability of using the proposed approach for selection of the diamond-ceramic composite components and the modes of heat treatment of the diamond-bearing layer when creating a tool. This approach will significantly expand the possibilities of manufacturing large-pore diamond-abrasive tools with a high service life at minimal material costs and will improve the processing of parts made of difficult-to-machine materials.

Lithium-Cation Conductivity of Solid Solutions in Li6-xZr2-xAxO7 (A = Nb, Ta) Systems

Li6-xZr2-xAxO7 (A = Nb; Ta) system with 0 < x < 0.30 is synthesized by glycine-nitrate method. Boundaries of solid solutions based on monoclinic Li6Zr2O7 are determined; temperature (200–600 °C) and concentration dependences of conductivity are investigated. It is shown that monoclinic Li6Zr2O7 exhibits better transport properties compared to its triclinic modification. Li5.8Zr1.8Nb(Ta)0.2O7 solid solutions have a higher lithium-cation conductivity at 300 °C compared to solid electrolytes based on other lithium zirconates due the “open” structure of monoclinic Li6Zr2O7 and a high solubility of the doping cations.

Profile of the companies participating in the Mexican national exports award

Objective: To identify the profile of the companies participating in the Mexican National Exportation Award (NEA) in the Large Agricultural Exporting Companies category (LAEC), by an information-gathering tool to determine the commercial lines of those businesses, their state of origin, and the exports destination. Methodology: a total of 17 questionnaires (n = 17), applied by the NEA to the LAEC category participants during the 2010-2018 period, were analyzed to determine the commercial business lines, their state of origin, and the destination of the exports. A problem tree was created to find opportunity areas to design solution proposals. The collected information was processed in the NetDraw 2.097 software to show the networks, their dominant actors (countries to which they export), and the products that the companies exported the most. Results: pork and vegetables business lines were identified. The latter revealed a sub-network of tomatoes and strawberries. A network was generated with an open structure comprising 17 nodes and 46 links where three export destination countries stood out: the USA with 15 links, Canada with six, and Japan with five. The highest exported product was the tomato in its different varieties, mainly to the U.S. and Canada. Limitations: Scarce information about the award on the internet. Access restrictions. Most of the exporting companies did not respond to the survey. Conclusions: the perishability of exported products determines the number of destination countries. The precariousness of Mexican agricultural exports was identified because companies trade only one product or a reduced number of them to only one country.

Current status of the rare British endemic Gentianella amarella subsp. occidentalis, Dune Gentian (Gentianaceae)

Gentianella amarella subsp. occidentalis, Dune Gentian, is a rare annual of dune slacks endemic to Western Britain. Its current status was compared to historic records. A maximum of 2250 plants were found in ten subpopulations in four sites in 2019-2020. It was not refound in three sites and 15 subpopulations. It is assessed as IUCN threat category ‘Endangered’. Its primary vegetation type is SD14d Salix repens - Campylium stellatum dune slack Festuca rubra subcommunity, within which it favours short, open structure on dry, low nutrient soils. Conservation requires managing and creating its niche in the dune slacks.

Stulov, Y. (2019). 100 US writers. Minsk: Vysheyshaya shkola. (In Russ.)

The review of the dictionary 100 US Writers [100 pisateley SShA] analyses the entries that cover biographical information, summarise the writer’s output and contain lists of their principal works and their translations into Russian and Belorussian, as well as the most significant research on the writer’s works. The reviewers find that the dictionary is very well executed. However, they are somewhat baffled by the selection principles. In Y. Stulov’s opinion, one should take into account new participants of the literary process and the level of the readers’ familiarity with authors whose books remained inaccessible for ideological reasons. While supporting his position in general, the reviewers point out several notable omissions, for example, P. Buck, B. Dylan, J. Irving, P. Theroux, L. Erdrich, etc. The book’s indisputable merit lies in its ‘open’ structure that allows for new individual entries to be included in subsequent editions.

MORPHONOLOGICAL TYPES AND PROPERTIES OF BASES VERBS OF WORD- FORMING UNITS IN THE UKRAINIAN LANGUAGE

The article describes the morphonological structure of word- forming units with indivisible and divisible bases verbs is clarified in the article and the morphonological types and properties of bases verbs of word-forming units in the Ukrainian language are determined. The morphonological structure of word-forming units is determined by the structure of the apical verb, morphonological transformations, morphonological positions, morphonological type, morphonological model. The ending of the verb base, which undergoes changes under the influence of the initial of the formant, signalize morphonological transformations. All word-forming units with an inarticulate verb are divited among 22 morphonological types, with an indivisible verb is divided between 50 morphonological types, notice the character of the verb base, complex morphonological transformations (consonant or vocal alternations, types of final consonant base), open, closed), increase of radical or suffix morpheme, change of accent positions (shift of emphasis on root or suffix morpheme). Morphonologically marked deverbatives of substantive, adjectival, verbative, adverbial blocks are analyzed. The character of realization and regularity of morphonological phenomena in word formation during the formation of deverbatives are influenced by structural and phonemic properties, characteristics of creative bases and word-forming affixes, features of the contact zone on the morpheme seam, stress position, truncation, number of syllables. Indivisible verb bases are characterized by open and closed verb bases, divisible verb bases are characterized only by open verb bases. For articulated verb bases, the open structure of the suffix (V, VCV) is typical, open or cover-open (CV). Analyzing the bases verbs of word-forming units in the Ukrainian language, it is appropriate to take into count the indivisibility and divisibility of bases verbs, the final formative basis, variability / non-variability of verb bases, formant initials, morphonological transformations, morphonological positions, presence / absence of constraints in compatibility.