Basic magnetic properties of magnetoactive elastomers of mixed content

The results of theoretical and experimental investigations of the polymer composites that belong to a class of magnetoactive elastomers with mixed magnetic content (MAEs-MC) are presented. The fundamental distinction of such composites from ordinary magnetoactive elastomers is that the magnetic filler of MAEs-MC comprises both magnetically soft (MS) particles of size 3-5 m and magnetically hard (MH) particles whose size is an order of magnitude greater. Since MH particles of the magnetic filler are mixed into a composition in a non-magnetised state, this can ensure preparation of samples with fairly homogeneous distribution of the filler. The 'initiation' process of a synthesised MAE-MC is done by its magnetisation in a strong magnetic field that imparts to the sample unique magnetic and mechanical properties. In this work, it is shown that the presence of MS particles around larger MH particles, firstly, causes an augmentation of magnetic moments, which the MH particles acquire during initiation, and secondly, enhances the magnetic susceptibility and remanent magnetisation of MAEs-MC. These magnetic parameters are evaluated on the basis of the macroscopic magnetostatics from the experimental data of spatial scanning of the field over the space around MAEs-MC made in the shape of a spheroid. A set of samples with a fixed MH and varying MS volume contents that are initiated in two different fields, is used. The developed mesoscopic model of magnetic interactions between the MH and MS phases is able to explain the experimentally observed dependencies of the magnetic parameters on the concentration of the MS phase. The problem is solved numerically under the assumption that the elastic matrix of MAEs-MC is rigid, i.e. the mutual displacements of the particles are negligible. The model helps to elucidate the interaction of the magnetic phases and to establish that the MS phase plays thereby a dual role. On the one hand, the MS phase screens out the field acting inside MH particles, and on the other hand, it forms mesoscopic magnetic bridges between adjoining MH particles, which in turn enhance their field. The combined interplay of these contributions defines the resulting material properties of MAEs-MC on the macroscopic scale. © 2020 The Author(s). Published by IOP Publishing Ltd

Features of Formation of Crystallographic Texture in Cells of Spacing Grid at their Stamping

The structural and textural heterogeneity of thin-walled tubes of Zr-1% Nb alloy used for stamping of the cells of the spacing grid (SG) was studied. It was found, that structure and texture of thin-walled tubes corresponds to incomplete recrystallization. During the increasing of recrystallization degree, the variation of crystal structure parameters of Nb solid solution i

Energy sustainability performance of the regional economy

The results of the study of the dynamics of energy intensity of gross regional product of the Sverdlovsk region for the period 1996 - 2003 years. and projections for the period up to 2015. The principal possibility of growth performance of the regional economy, without a significant increase in the consumption of primary fuel

Factors Controlling the Reactivity of Catalytically Active Monolayers on Metal Substrates

The focus of this work is on the Pt/MS structures (MS = Au, Ir, Ru, or Pt substrate), as promising electrocatalysts and a prototype for more general systems: (active element monolayer)/(metal substrate) (AE/MS). We evaluate from first principles the effects of AE monolayer strain and the interlayer AE-MS electronic state hybridization on surface reactivity and reveal rationale for the interlayer hybridization to dominate over the strain effect in determining the AE/MS surface reactivity. We find, however, that, if AE is weakly bound to MS, the surface electronic structure does not suffice to characterize the surface reactivity, because of involvement of other factors related to lattice response to adsorption of a reaction intermediate. Guided by our findings, we trace surface reactivity to a newly introduced hybridization parameter that reflects important features of the electronic structure of the AE/MS surface, which are not taken into account in the original d-band center model. © 2013 American Chemical Society

Energy sustainability performance of the regional economy

The results of the study of the dynamics of energy intensity of gross regional product of the Sverdlovsk region for the period 1996 - 2003 years. and projections for the period up to 2015. The principal possibility of growth performance of the regional economy, without a significant increase in the consumption of primary fuel

Rational Design of Competitive Electrocatalysts for Hydrogen Fuel Cells

We report a mechanism-based screening technique to rapidly identify eukaryotic topoisomerase I targeting agents. The method is based on genetic tagging of topoisomerase I to immobilize the enzyme on a solid surface in a microtiter well format. DNA is added to the wells, and retained DNA is detected by Pico Green fluorescence. Compounds that result in an increase in Pico Green staining represent potential topoisomerase interfacial poisons, whereas those that reduce fluorescence report catalytic inhibitors; therefore, the solid phase assay represents a bimodal readout that reveals mechanisms of action. The method has been demonstrated to work with known interfacial poisons and catalytic inhibitors. This method is rapid, robust, economical, and scalable for large library screens. © 2011 Elsevier Inc. All rights reserved

Nature of the Selenium Submonolayer Effect on the Oxygen Electroreduction Reaction Activity of Ru(0001)

California\u27s Sacramento-San Joaquin Delta is the major hub of California\u27s water supply system and is central to the ecosystem of many native threatened and endangered species. Conflicts over the Delta have evolved over more than a century. This paper traces changes in this conflict in game-theoretic terms, with its implications for the region\u27s physical and ecological decline and governance. The Delta is not a zero-sum problem and win-win resolutions may exist if stakeholders cooperate. Game theory provides some insights on the potential for win-win solutions. The Delta problem has had a Prisoner\u27s Dilemma structure, in which stakeholder self-interest makes cooperation unlikely within a reasonable time frame. However, the core of the Delta conflict is changing as the unsustainable future becomes more widely understood. Today\u27s Delta problem has characteristics of a Chicken game, where cooperation is in everyone\u27s interest, but it is unlikely because parties deviating from the status quo are likely to bear more of the costs of a long-term solution. The State of California may become the victim (or chicken) of the Delta game, bearing the greatest costs, if it continues to rely on leaving parties to develop voluntary cooperative solutions without a sufficient mechanism for enforcing cooperation. © 2012 American Society of Civil Engineers