Influence of Silica Nanoparticles on the Crystallization Behavior of and Proton Relaxation in Cesium Hydrogen Sulfate

The influence of nanoparticulate SiO_2 on the crystallization behavior of CsHSO_4 from aqueous solution has been quantitatively evaluated using powder X-ray diffraction (XRD) and ^1H magic angle spinning nuclear magnetic resonance (NMR) spectroscopy. It is shown that SiO_2 induces amorphization of a portion of CsHSO_4 and crystallization of the otherwise metastable phase II form of CsHSO_4. The fraction of amorphized CsHSO_4 (as determined from an evaluation of the XRD peak intensity) was found to increase from 0% in the absence of SiO_2 to fully amorphized in the presence of 90 mol % (~70 wt %) SiO_2. Within the crystalline portion of the composites, the weight fraction of CsHSO_4 phase III was observed to fall almost monotonically from 100% in the absence of SiO_2 to about 40% in the presence of 70 mol % SiO_2 (from both XRD and NMR analysis). These results suggest a crystallization pathway in which SiO_2 particles incorporate an amorphous coating of CsHSO_(4-)like material and are covered by nanoparticulate CsHSO_(4-II), which coexists with independently nucleated particles of CsHSO_(4-III). In composites with small molar fractions of CsHSO_4, the entirety of the acid salt is consumed in the amorphous region. At high CsHSO_4 content, the extent of amorphization becomes negligible, as does the extent of crystallization in metastable phase II. The phase distribution was found to be stable for over 1 year, indicating the strength of the stabilization effect that SiO_2 has on phase II of CsHSO_4

Investigation of structure and properties of bury barrier layers at low energy carbon and oxigen ions

There is actual investigation of the processes creating the buried barrier layers that prevent diffusion of high-temperature coating materials because of the development of ion and ion-plasma technologies, surface treatment of material. In the present work we discuss the results on the thermal stability, structure, physical and mechanical properties of the buried barrier layers formed 2*1018 ion/sm2 , by ion implantation of oxygen and carbon (the dose the energy of 1.5 – 2 MeV) accelerator to the DC-60. Nuclear spectroscopic techniques involving X-ray analysis systematic studies of the influence of the buried barrier layer on the thermally induced processes in the layered system Fe-Be. It is established: the sequence of phase transitions in the surface layers and inside the sample during isothermal annealing. It is shown that the implanted oxygen ions buried barrier layer in the matrix of Fe slow mutual diffusion of beryllium atoms and iron atoms. The kinetics of the process of mutual diffusion of Fe and Be in a solution Fe (Be) for both multi-layered systems with a layer of implanted of oxygen and without it. The evolution of the distribution of the oxygen implanted layer in the copper and the effect of thermal annealing. It is shown that even at an annealing temperature of ~ 200ºC in this system is the diffusion of oxygen into the sample of copper. Consequently, the oxygen cannot be used as a subsurface barrier layer in copper, in contrast to iron, where oxygen-implanted layer remains stable at much higher temperatures. The research phase formation in iron implanted with carbon and deposited on the surface layer of beryllium. It is established that the sample implanted with a layer of carbon formation on the surface Fe2 phase begins after 5 hours annealing at 650ºC. For the case without implantation – education phase not fixed. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2089

Materials Chemistry of Superprotonic Solid Acids

Solid acid is a class of materials that shows potential as a fuel cell electrolyte. Understanding the phase and mechanical stability are required for further development of this technology. We addressed both issues in this work. We expanded the use of the crystallographic theory of the phase transformation to three major classes of solid acids. That allowed us to relate material properties hysteresis to fundamental crystallographic and thermodynamic parameters. The understanding of the mechanism of the transformation can guide the effort to create materials with desired hysteresis. Careful investigation of the thermal and phase behavior of CsHSO₄, CsH₂PO₄, Rb₃H(SeO₄)₂ and in Cs1-xRbxH₂PO₄ solid solution series for both low and high temperature phases was performed and crystal symmetry and lattice parameters for Cs0.75Rb0.25H₂PO₄, T=240°C phase were found for the first time. Consistency between predicted and measured properties was shown for all three different classes of solid acids as well as for the isostructural solid solution series. Nanocomposite materials based on cesium hydrogen sulfate and nanometer size silica were characterized. We observed 30-40 nm size surface stabilization of our material at the high temperature phase, otherwise metastable at room temperature. We developed methods to quantitatively study interface phases and its effect on ion mobility. The method allowed us to quantitatively find crystalline and amorphous amounts in the composites. We observed 3-4 order decrease in spin-lattice relaxation values of the metastable phase in the composite. Solid state NMR allowed surface interactions directly and suggest high ion mobility. Strong effect on superprotonic transition temperature in composites was observed. Superprotonic phase was stable in composites at temperatures up to 70°C below phase transition compared with pure phase CsHSO₄. The mechanism and activation energy of the creep plastic deformation in CsHSO4 were found. Based on that, a method to reduce creep by 1-2 orders of magnitude was developed and creep-resistant material was synthesized.</p

Substrate-Selective C-H Functionalization for the Preparation of Organosulfur Compounds from Crude Oil-Derived Components

The direct utilization of a natural feedstock in organic synthesis is an utmost challenge because the selective production of one product from a mixture of starting materials requires unprecedented substrate selectivity. In the present study, a simple and convenient procedure is evaluated for the substrate-selective alkenylation of a single component in a mixture of organosulfur compounds. Pd-catalyzed alkenylation of two-, three-, four-, and five-component mixtures of crude oil-derived sulfur species led to the exclusive C–H functionalization of only one compound. The observed remarkable substrate selectivity opens new opportunities for sustainable organic synthesis

Simulation Modeling as a Tool for Ensuring Sustainable Development and Competitiveness of an Enterprise

CC BY-NC 4.0The work performed is unique in its kind, since it represents the development of instrumental methods for studying an urgent problem – the increase in competitiveness and ensuring sustainable development of industrial enterprises. The purpose of the study is to develop a system for assessing the impact of institutional factors on the competitiveness and innovation activity of an industrial enterprise. The analytical toolkit is simulation modeling diagrammatically represented by graphical notations illustrating system dynamics model. Based on the available world research, four main components of industrial enterprise competitiveness are identified - the competitiveness of products; strategic positioning; innovation activity of both - the enterprise and the institutional environment; and resource efficiency. Based on the identified components, a methodology for their calculation and for computation of a multiplicative composite indicator describing competitiveness has been developed. The influence of the intra-firm and institutional factors on the enterprise innovation activity is discussed as a separate segment of this method. It is shown that the institutional environment to a greater extent affects the company competitiveness through its innovation activity. The intra-firm factors (such as the enterprise’s material, scientific and technical resources, organizational and corporate culture, strategic management) expand the influence of the industrial market institutional environment. Thus, all enterprises located in the same industrial market have equal conditions for their innovative activities. Based on the elaborated system, a simulation model of industrial enterprise competitiveness is developed, which shows it as a set of cause-and-effect relationships and feedback loops. The designed simulation model may be adapted to any manufacturing company and allows simple simulation experiments

Some Typical Mistakes in Solutions of Tasks At the Region Stage of the All-Russian Physics Contest for School Students

Представлен краткий обзор ошибок, сделанных школьниками при решении задач регионального этапа олимпиады по физике в Тюменской области.Is presented the brief review of mistakes in solutions of physical tasks, those was making school students on the Tyumen region stage of the All-Russian contest

Влияние на организм человека гипоксии при высокогорных восхождениях

External respiratory function was studied in those engaged in mountaineering. A negative correlation was found between the intensity of exercise and the changes in vital capacity under mountainous conditions. Changes occurring in the levels of glucose and cholesterol were considered in tourists.Проведены исследования функции внешнего дыхания у участников горных туристических походов. Отмечена выраженная отрицательная корреляционная связь мужду интенсивностью физических нагрузок и изменениями жизненой емкости легких в условиях высокогорья. Рассмотрены изменения уровня глюкозы, холестерина у туристов

Effect of irradiation with low-energy alpha particles on the structural-phase state of coatings of triple nitride systems based on titanium and vanadium on steel

The paper presents the results of studies of the effect of alpha-particle irradiation on the structural-phase composition of nitride coatings CrTiN, MoTiN and NbTiN on the surface of a steel substrate. The coatings were formed by vacuum-arc condensation in a gas medium with N2 using ion bombardment with the use of Ti, Cr, and Mo cathodes. In addition, coatings in a N2 gas medium on a steel substrate were produced by magnetron sputtering from Ti and Nb metals. Experimental data and the analysis of state diagrams of ternary systems of nitrides based on titanium and vanadium with transition metals of IVA-VIA groups have allowed deriving criteria for choosing materials for production of nitride coatings with a fairly high radiation stability