Vendian-Cambrian granites of the Salatim suture zone (the Northern Urals): Geochemistry of zircons, source composition, geochronological and geodynamical consequences

Research subject. The composition and isotope systems of zircons and their host granites from the Krutorechensky complex (western part of the Main Uralian fault zone, Northern Urals) were investigated. Methods. The U-Pb age, trace element contents and Lu-Hf isotopes in the zircons under study were determined by LA-ICP-MS (Ulan-Ude, Ekaterinburg). TIMS was used to determine Sm-Nd isotopes in the rocks. Results and Discussion. It was shown that the morphology and composition of the main zircon group from granites confirm their magmatic origin and the absence of alteration. It means that the previously defined Vendian-Cambrian (542 Ma) age of the granites remains valid. The relics ancient (1043–122 Ma) cores were probably inherited from Isherim suite rocks. The source of such detrital grains could have been the rocks from the East-European platform basement. Young zircons (400 Ma) differing strongly from others in composition could have been formed around the already existing grains produced by a fluid generated under the action of plume activity. The source for granite melting was mainly of a crust nature: εNd(t) = –6, εHf(t) = –6…–9, initial ratio (87Sr/86Sr)i = 0.796943. In terms of lithology, the source rocks correspond to sandstones with a small admixture of clay components. The obtained information confirms the necessity to further investigate questions concerning the area of distribution and the age of the Sarankhapnorsk suite within the Krutorechensky complex, as well as the position of the eastern boundary of the Isherim block. Conclusion. The obtained results can be used in geological mapping.

Synthesis and properties of na nomagnetite for the preparation of biocomposites

Magnetite powder (FeO·Fe2O3 or Fe3O4) is obtained by the chemical precipitation method, using FeCl3·6H2O and FeCl2·4H2O as a starting materials in the presence of hydrazine N2H4 at a temperature of 80 °C. X-ray diffraction analysis, infrared spectroscopy, and scanning electron microscopy are used for the study of the phase composition and morphology of the synthesized powder. Its specific surface area and magnetic properties such as, in particular, the specific saturation magnetization, coercive force and residual induction are investigated. It is established that the composition of the synthesized powder is represented by magnetite as the main phase with a small admixture of hematite. It is shown that the particles of the obtained magnetite have sizes of 33-84 nm and tend to the agglomeration. The prepared powder has superparamagnetic properties (specific magnetization — 35 A · m2/kg, coercive force — 0.24 kA/m, residual induction — 0.009 T) and is promising for the biocomposite creation.

Phase Formation in Contact Melting in a Cadmium-Indium System Doped with Sodium

This study is dedicated to application of x-ray methods to investigate phase formation in contact melting in a Cd-In system after introduction of a small admixture of sodium to cadmium, including cases of electrotransport. Formation of both two-and three-component intermetallic compounds has been established. An attempt is made to explain the results.

Influence of Doping with Indium onto Contact Melting of Tin and Bismuth

This study is dedicated to investigating contact melting, including cases of electrotransport is a Sn-Bi system after introduction of a small admixture of indium. It has been shown that the dopant ambiguously influences the rate of the contact melting. The structure of obtained alloys is strongly non-uniform and abounds with dendritic forms. An attempt is made to explain the results.

Nanoscale ordering of planar octupolar molecules for nonlinear optics at higher temperatures

We develop scenarios for orientational ordering of an in-plane system of small flat octupolar molecules at the low-concentration limit, aiming towards nonlinear-optical (NLO) applications at room temperatures. The octupoles interact with external electric poling fields and intermolecular interactions are neglected. Simple statistical-mechanics models are used to analyze the orientational order in the very weak poling limit, sufficient for retrieving the NLO signals owing to the high sensitivity of NLO detectors and measurement chains. Two scenarios are discussed. Firstly, the octupolar poling field is imparted by a system of point charges; the setup is subject to cell-related constraints imposed by mechanical strength and dielectric breakdown limit. The very weak octupolar order of benchmarking TATB molecules is shown to emerge at Helium temperatures. The second scenario addresses the dipoling of octupolar molecules with a small admixture of electric dipolar component. It requires a strong field regime to become effective at Nitrogen temperature range. An estimation of the nonlinear susceptibility coefficient matrix for both scenarios is done in the high-temperature (weak interaction) limit formalism. We argue that moderate modifications of the system like, e.g., an increase of the size of the octupole, accompanied by dipole-assisted octupoling, can increase the poling temperature above Nitrogen temperatures.

Assessment of load and quality of logging residues from clear-felling areas in Järvselja: a case study from Southeast Estonia

The properties of biomass-based fuel and combustion tests showed that logging residues are promising renewable energy sources. The data used in this study were collected from four clear-felling areas in Järvselja Training and Experimental Forest Centre, Southeast Estonia in 2013–2014. Logging was carried out by harvesters in Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies [L.] Karst.), silver birch (Betula pendula Roth.) and black alder (Alnus glutinosa L. Gaertn.) dominated stands with a small admixture of other tree species according to the cut-to-length method and logging residues were placed in heaps. The aim of this research is to assess different characteristics of logging residues (quantity, moisture content, energetic potential, ash content and amount) in clear-felling areas. The highest load of slash was measured on the birch dominated study site, where the dry weight of the logging residues was 29 t ha−1. Only the branch fraction moisture content on the black alder dominated site (35.4%) was clearly different from respective values on other sites (21.6–25.4%). The highest calorific value of the residues was assessed with the residues from the birch dominated site, where in moist sample it was 365 GJ ha−1 and in dry matter 585 GJ ha−1. The heating value of the fresh residues is highest in coniferous trees. The highest ash content in branch segments was registered for the black alder dominated site. Järvselja data indicate higher quality in conifer dominated sites, yet a higher load of logging residues in broadleaf dominated stands.

Formation of Nanostructured Carbon from [Ni(NH3)6]3[Fe(CN)6]2

The products of thermal decomposition in an argon atmosphere of [Ni(NH3)6]3[Fe(CN)6]2 as a precursor has been studied. Decomposition products were studied up to 800 °C. Above 600 °C, all coordination bonds in the residues are broken with a formation of Ni3Fe, Fe, and free carbon with a small admixture of nitrogen. Elementary carbon can be easily separated from metals by treatment with a water solution of hydrochloric acid. Only carbon is responsible for the specific surface of the composite products. The released carbon has a high degree of graphitization and begins to oxidize in air above 500 °C and is completely oxidized above 700 °C.

Neutron-Star-Merger Equation of State

In this work, we discuss the dense matter equation of state (EOS) for the extreme range of conditions encountered in neutron stars and their mergers. The calculation of the properties of such an EOS involves modeling different degrees of freedom (such as nuclei, nucleons, hyperons, and quarks), taking into account different symmetries, and including finite density and temperature effects in a thermodynamically consistent manner. We begin by addressing subnuclear matter consisting of nucleons and a small admixture of light nuclei in the context of the excluded volume approach. We then turn our attention to supranuclear homogeneous matter as described by the Chiral Mean Field (CMF) formalism. Finally, we present results from realistic neutron-star-merger simulations performed using the CMF model that predict signatures for deconfinement to quark matter in gravitational wave signals.

Universes Inside a Black Hole with the de Sitter Interior

We outline the basic ideas and analyze the possibilities of the quantum birth of universes inside regular black holes with the de Sitter interior replacing a singularity. We compare different cases and show that the most plausible case is the birth of a flat universe from an initial quantum fluctuation with a small admixture of radiation and strings with the negative deficit angle, which provides the existence of a potential barrier needed for quantum tunneling.