ЕКОНОМІЧНА ЕФЕКТИВНІСТЬ ХІМІЧНОЇ МЕЛІОРАЦІЇ ФОСФОГІПСОМ НА ІРИГАЦІЙНО СОЛОНЦЮВАТИХ ЧОРНОЗЕМАХ

Irrigation is a major method for the intensification of agriculturalproduction. Irrigation loses its influence in conditions of soil salinityirrigation soils, where the average yield is reduced by 20-40%.Chemical melioration leads increases of crop yields with parallelimprovement of physicochemical properties and soil fertility, whichmakes it possible to obtain high yields with conditions of irrigationsalinization for the production of necessary products for thepopulation, effective economic development of the country andreproduction of the main resource potential: soils. In our experiments, when the phosphogypsum was introduced as a chemical reclamation element, the yield of crops increased with increasing of the norm introduction.Irrigation, as well as without him, received the greatest revenues with introduction of phosphogypsum in autumn under basic tillage at the norm of 6 t/ha – 1539 grn. on 1 ha at reintroduction ofphosphogypsum in the first year of the aftereffect. Irrigation increases the intensification of farming, but, as our studies have shown, not on salinizated soils. With Irrigation the crop productivity of spring barley increased by 5.9 centners per ha, corn for grain – by 15.4 centners per ha compared to unirrigated control. The introduction of phosphogypsum from irrigation increased the crop productivity of winter wheat to 47.8-52.0 centners per ha (increase of 4-7% compared to control). The crop productivity of spring barley under irrigated conditions during chemical melioration by phosphogypsum increased from 32.9 centners per ha at the control to 36.9 centners per ha when the phosphogypsum was introduced in autumn under the basic soil tillage at a norm of 6 t/ha (increase by 10.8%). Whereas in unirrigated variants winter wheat crop productivity values with chemical melioration variably differ from each other (observation in 2012 and 2013), with irrigation these indexes are somewhat smoothed by better dissolving of remanufactured remnants and assimilation of nutrient elements by plants.Most economic efficiency of using phosphogypsum observed withnorm of 3 t/ha under cultivation in the spring while without irrigation the best results were with introduction the phosphogypsum in autumn under the basic tillage of soil at the norm of 6 t/ha.Орошение является основным мероприятием интенсификациисельскохозяйственного производства. Орошение теряет свое влияние в условиях ирригационного осолонцевания почв, где в среднем урожайности снижаются на 20-40%. Химическая мелиорация приводит к повышению урожайности сельскохозяйственных культур с параллельным улучшением физико-химических свойств и плодородия почв.В наших опытах при внесении фосфогипса как химического мелиоранта урожайность сельскохозяйственных культур увеличивалась при увеличении нормы внесения. При орошении и без него наибольшую выручку получили при внесении фосфогипса осенью под основное возделывание почвы нормой 6 т/га – 1539 грн. на 1 га при повторном внесении фосфогипса на первый год последействия.Наибольшая экономическая эффективность использования фосфогипса наблюдается при норме 3 т/га под культивацию весной при орошении, тогда как без орошения лучшие результаты были при внесении фосфогипса осенью под основное возделывание почвы нормой 6 т/а.Приріс урожайності сільськогосподарських культур під впливомхімічної меліорації фосфогіпсом різними розрахунковими дозамипри зрошенні та без нього. Економічна ефективність внесення фосфогіпсу

Spin-transfer mechanism of ferromagnetism in polymerized fullerenes: AbinitioAb initio calculations

A mechanism of the high temperature ferromagnetism in polymerized fullerenes is suggested. It is assumed that some of the C$_{60}$ molecules in the crystal become magnetically active due to spin and charge transfer from the paramagnetic impurities (atoms or groups), such as hydrogen, fluorine, hydroxyl group OH, amino group NH$_2$, or methyl group CH$_3$, dispersed in the fullerene matrix. The exchange interaction between the spins localized on the magnetically active fullerenes is evaluated using \textit{ab initio} calculations. The nearest neighbour and next nearest neighbour exchange interaction is found to be in the range $0.1\div 0.3$ eV, that is, high enough to account for the room temperature ferromagnetism.Comment: typos corrected, 8 pages, 3 figures, LaTe

A Latent Class Analysis of University Lecturers’ Switch to Online Teaching during the First COVID-19 Lockdown: The Role of Educational Technology, Self-Efficacy, and Institutional Support

The switch to emergency remote teaching (ERT) due to the first COVID-19 lockdown demanded a lot from university lecturers yet did not pose the same challenge to all of them. This study sought to explain differences among lecturers (n = 796) from universities in France, Germany, Switzerland, and the UK in their use of educational technology for teaching, institutional support, and personal factors. Guided by the Social Cognitive Theory (SCT), lecturers’ behavior (educational technology use), environment (institutional support), and personal factors (ERT self-efficacy, continuance intentions, and demographics) were examined. Latent class analysis was employed to identify different types of lecturers in view of educational technology use, while multinomial regression and Wald chi-square test were used to distinguish classes. The largest latent class were Presenters (45.6%), who focused on content delivery, followed by Strivers (22.1%), who strived for social interaction, Routineers (19.6%), who were ready for online teaching, and Evaders (12.7%), who evaded using technology for educational purposes. Both personal factors and perceived institutional support explained class membership significantly. Accordingly, Evaders were older, less experienced, and rarely perceived institutional support as useful. Routineers, the Evaders’ counterparts, felt most self-efficient in ERT and held the highest continuance intentions for educational technology use. This research suggests that universities engage lecturers in evidence-based professional development that seeks shared visions of digital transformation, networks and communities, and design-based researc

Induced Magnetic Ordering by Proton Irradiation in Graphite

We provide evidence that proton irradiation of energy 2.25 MeV on highly-oriented pyrolytic graphite samples triggers ferro- or ferrimagnetism. Measurements performed with a superconducting quantum interferometer device (SQUID) and magnetic force microscopy (MFM) reveal that the magnetic ordering is stable at room temperature.Comment: 3 Figure

Fingerprints of Spin-Orbital Physics in Crystalline O2_2

The alkali hyperoxide KO$_2$ is a molecular analog of strongly-correlated systems, comprising of orbitally degenerate magnetic O$_2^-$ ions. Using first-principles electronic structure calculations, we set up an effective spin-orbital model for the low-energy \textit{molecular} orbitals and argue that many anomalous properties of KO$_2$ replicate the status of its orbital system in various temperature regimes.Comment: 4 pages, 2 figures, 1 tabl

Localized States at Zigzag Edges of Multilayer Graphene and Graphite Steps

We report the existence of zero energy surface states localized at zigzag edges of $N$-layer graphene. Working within the tight-binding approximation, and using the simplest nearest-neighbor model, we derive the analytic solution for the wavefunctions of these peculiar surface states. It is shown that zero energy edge states in multilayer graphene can be divided into three families: (i) states living only on a single plane, equivalent to surface states in monolayer graphene; (ii) states with finite amplitude over the two last, or the two first layers of the stack, equivalent to surface states in bilayer graphene; (iii) states with finite amplitude over three consecutive layers. Multilayer graphene edge states are shown to be robust to the inclusion of the next nearest-neighbor interlayer hopping. We generalize the edge state solution to the case of graphite steps with zigzag edges, and show that edge states measured through scanning tunneling microscopy and spectroscopy of graphite steps belong to family (i) or (ii) mentioned above, depending on the way the top layer is cut.Comment: 6 pages, 4 figure

Evidence for Insulating Behavior in the Electric Conduction of (NH3_3)K3_3C60_{60} Systems

Microwave study using cavity perturbation technique revealed that the conductivity of antiferromagnet (NH$_3$)K$_{3-x}$Rb$_x$C$_{60}$ at 200K is already 3-4 orders of magnitude smaller than those of superconductors, K$_3$C$_{60}$ and (NH$_3$)$_x$NaRb$_2$C$_{60}$, and that the antiferromagnetic compounds are {\it insulators} below 250K without metal-insulator transitions. The striking difference in the magnitude of the conductivity between these materials strongly suggests that the Mott-Hubbard transition in the ammoniated alkali fullerides is driven by a reduction of lattice symmetry from face-centered-cubic to face-centered-orthorhombic, rather than by the magnetic ordering.Comment: accepted for publication in PR

«Green Economy», Nuclear Energy and "Natural Capitalism": Dialectics of Development

The article reveals the content of the concepts of "green economy"and "natural capitalism", the history of their appearance in science and the modern semantic context. The role of the idea of coevolution of the modern biosphere and the processes of transformation of traditional biogeocenoses into anthropobiogeocenoses with a decisive human influence in them is revealed. The risks of nuclear energy development and the state of the "green economy"are compared. The necessity of a more active formation of a new type of economy - an ecological economy that meets the tasks of reproduction of the natural environment is put forward and justified. The initial step on this path should be the adoption of the "Environmental Code"of the Russian Federation and the humanitarian reformatting of the thinking of the person based on ecological culture and ecological consciousness. © Published under licence by IOP Publishing Ltd

Interaction Between Superconducting and Ferromagnetic Order Parameters in Graphite-Sulfur Composites

The superconductivity of graphite-sulfur composites is highly anisotropic and associated with the graphite planes. The superconducting state coexists with the ferromagnetism of pure graphite, and a continuous crossover from superconducting to ferromagnetic-like behavior could be achieved by increasing the magnetic field or the temperature. The angular dependence of the magnetic moment m(alpha) provides evidence for an interaction between the ferromagnetic and the superconducting order parameters.Comment: 11 pages, 4 figures, to be published in Phys. Rev.

Magnetic properties of carbon phases synthesized using high pressure-high temperature treatment

Two sets of samples were synthesized at 3.5 GPa near the point of C60 cage collapse at different annealing times. A clear structural transformation from mixture of C60 polymeric phases to graphite-like hard carbon phase was confirmed by X-ray diffraction and Raman spectroscopy. Magnetic force microscopy and superconducting quantum interference device were used to characterize the magnetic properties of the synthesized samples. We found that the sample preparation conditions used in this study are not suitable to produce bulk magnetic carbon.Comment: 26 pages, 7 figure