Thermocatalytic conversion of petroleum paraffin in the presence of tungsten carbide powders

Russia occupies the third place in the world in terms of stocks of heavy oil raw materials. The development of deposits of light and medium oils makes it inevitable to involve heavy, as well as residual, petroleum raw materials in processing to meet the growing demand for petroleum products. Increase of the depth of oil processing possible in various ways, one of which is the use of new efficient catalysts, resistant to corrosion, poisoning and coking. Tungsten carbide, meeting these requirements, is a promising starting compound for the production of cracking catalysts for heavy oil feedstocks. The influence of tungsten carbide and its calcination temperature on the composition and yield of oil paraffin cracking products on the resulting catalysts was studied to investigate its catalytic activity, the optimum treatment temperature of tungsten carbide was determined. The high catalytic activity of a WC sample calcined at 420°C is shown. Using the physicochemical methods of investigation, the properties of tungsten carbide samples, as well as the composition and properties of the paraffin cracking products in the presence of the catalysts obtained, were studied

Legal Basis for the Development of Social Capital in the Conditions of the State Transition to an Innovative Economy

The Union state-the Union of Russia and Belarus – is the most significant integration project in the CIS space, which marked the change of centrifugal tendencies in the post-Soviet space by centripetal ones. Russia and Belarus were among the first CIS member States to realize the need for close integration. Almost immediately after the collapse of the Soviet Union, Russia and Belarus signed bilateral trade and economic agreements, which recognized the right of the parties to pursue an independent foreign economic policy. Thus, Russia and Belarus were the pioneers of integration processes in the region.El estado de la Unión - la Unión de Rusia y Belarús - es el proyecto de integración más importante en el espacio de la CEI, que marcó el cambio de las tendencias centrífugas en el espacio postsoviético por las centrípetas. Rusia y Belarús fueron los primeros miembros de los estados de CEI en darse cuenta de la necesidad de una estrecha integración. Casi inmediatamente después del colapso de la Unión Soviética, Rusia y Bielorrusia firmaron acuerdos comerciales y económicos bilaterales, que reconocían el derecho de las partes a perseguir una política económica extranjera independiente. Así, Rusia y Belarús fueron los pioneros de los procesos de integración en la región

Spectral-Kinetic Characterization of YF₃: Eu³⁺ and YF₃: (Eu³⁺, Nd³⁺) Nanoparticles for Optical Temperature Sensing

YF3: (Eu3+, Nd3+) nanoparticles (orthorhombic phase, D~130 nm) were synthesized via the co-precipitation method, with subsequent hydrothermal treatment and annealing. The Eu3+ τdecay linearly descends with the increase of temperature in the 80–320 K range. The τdecay (T) slope values of the annealed YF3: Eu3+ (2.5 and 5.0 mol.%) nanoparticles were the highest (110·10−4 and 67·10−4, μs/K) in the whole 80–320 K range, respectively. Thus, these samples were chosen for further doping with Nd3+. The maximum Sa and Sr values based on the LIR (IEu/INd) function were 0.067 K−1 (at 80 K) and 0.86%·K−1 (at 154 K), respectively. As mentioned above, the single-doped YF3: Eu3+ (2.5%) nanoparticles showed the linearly decreasing τdecay (T) function (5D0–7F1 emission). The main idea of Nd3+ co-doping was to increase this slope value (as well as the sensitivity) by increasing the rate of τdecay (T) descent via the addition of one more temperature-dependent channel of 5D0 excited state depopulation. Indeed, we managed to increase the slope (Sa) to 180·10−4 K−1 at 80 K. This result is one of the highest compared to the world analogs

Thermocatalytic conversion of petroleum paraffin in the presence of tungsten carbide powders

Russia occupies the third place in the world in terms of stocks of heavy oil raw materials. The development of deposits of light and medium oils makes it inevitable to involve heavy, as well as residual, petroleum raw materials in processing to meet the growing demand for petroleum products. Increase of the depth of oil processing possible in various ways, one of which is the use of new efficient catalysts, resistant to corrosion, poisoning and coking. Tungsten carbide, meeting these requirements, is a promising starting compound for the production of cracking catalysts for heavy oil feedstocks. The influence of tungsten carbide and its calcination temperature on the composition and yield of oil paraffin cracking products on the resulting catalysts was studied to investigate its catalytic activity, the optimum treatment temperature of tungsten carbide was determined. The high catalytic activity of a WC sample calcined at 420°C is shown. Using the physicochemical methods of investigation, the properties of tungsten carbide samples, as well as the composition and properties of the paraffin cracking products in the presence of the catalysts obtained, were studied

Quasi-2D Co3O4 nanoflakes as an efficient gas sensor

Here, we study quasi-two-dimensional crystals of Co3O4 grown by electrochemical synthesis on Pt electrodes with a nanoflake morphology to serve as a gas sensor. When synthesizing in aqueous electrolytes under applied electrical bias, the material follows a self-hierarchical architecture to primarily appear as the hexagonal nanoflakes α-Co(OH)2. After heating up to 300 °C in air, the as-synthesized material transforms to Co3O4, preserving the original hierarchical morphology. The Co3O4 nanoflakes have been found to have remarkable chemiresistive response when exposed to various kinds of alcohol vapors, at low ppm concentrations in a mixture with air, over a wide range of temperatures up to 300 °C with a detection limit down to the ppb range with direct dependence on the molecule weight of the alcohol. We explain the observed features of the gas response of the Co3O4 nanoflakes by a shift in the electron density under the chemisorption of VOCs, verified by DFT calculations.Peer reviewe

Anticrossing of Landau Levels in HgTe/CdHgTe (013) Quantum Wells with an Inverted Band Structure

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Physical Background for Luminescence Thermometry Sensors Based on Pr3+:LaF3 Crystalline Particles

The main goal of this study was creating multifunctional nanoparticles based on rare-earth doped LaF3 nanocrystals, which can be used as fluorescence thermal sensors operating over the 80–320 K temperature range including physiological temperature range (10–50°C). The Pr3+:LaF3 (CPr = 1%) microcrystalline powder and the Pr3+:LaF3 (CPr = 12%, 20%) nanoparticles were studied. It was proved that all the samples were capable of thermal sensing into the temperature range from 80 to 320 K. It was revealed that the mechanisms of temperature sensitivity for the microcrystalline powder and the nanoparticles are different. In the powder, the 3P1 and 3P0 states of Pr3+ ion share their electronic populations according to the Boltzmann and thermalization of the 3P1 state takes place. In the nanoparticles, two temperature dependent mechanisms were suggested: energy migration within 3P0 state in the temperature range from 80 K to 200 K followed by quenching of 3P0 state by OH groups at higher temperatures. The values of the relative sensitivities for the Pr3+:LaF3 (CPr = 1%) microcrystalline powder and the Pr3+:LaF3 (CPr = 12%, 20%) nanoparticles into the physiological temperature range (at 45°C) were 1, 0.5, and 0.3% °C−1, respectively

Coprecipitation Method of Synthesis, Characterization, and Cytotoxicity of Pr 3+

The Pr3+:LaF3 (CPr = 3, 7, 12, 20, 30%) nanoparticles were characterized by means of high-resolution transmission electron microscopy, X-ray diffraction, optical spectroscopy, energy dispersive X-ray spectroscopy, dynamic light scattering, and MTT assay. It was revealed that the average diameter of all the NPs is around 14–18 nm. The hydrodynamic radius of the Pr3+:LaF3 (CPr = 7%) nanoparticles strongly depends on the medium. It was revealed that hydrodynamic radii of the Pr3+:LaF3 (CPr = 7%) nanoparticles in water, DMEM, and RPMI-1640 biological mediums were 18 ± 5, 41 ± 6, and 186 ± 8 nm, respectively. The Pr3+:LaF3 (CPr = 7%) nanoparticles were nontoxic at micromolar concentrations toward COLO-320 cell line. The lifetime curves were fitted biexponentially, and for the Pr3+:LaF3 (CPr = 7%) NPs, the luminescence lifetimes of Pr3+ ions were 480 ± 2 and 53 ± 5 nanosec

Shedding Light on Heavy Metal Contamination: Fluorescein-Based Chemosensor for Selective Detection of Hg²⁺ in Water

This article discusses the design and analysis of a new chemical chemosensor for detecting mercury(II) ions. The chemosensor is a hydrazone made from 4-methylthiazole-5-carbaldehyde and fluorescein hydrazide. The structure of the chemosensor was confirmed using various methods, including nuclear magnetic resonance spectroscopy, infrared spectroscopy with Fourier transformation, mass spectroscopy, and quantum chemical calculations. The sensor’s ability in the highly selective and sensitive discovery of Hg2+ ions in water was demonstrated. The detection limit for mercury(II) ions was determined to be 0.23 µM. The new chemosensor was also used to detect Hg2+ ions in real samples and living cells using fluorescence spectroscopy. Chemosensor 1 and its complex with Hg2+ demonstrate a significant tendency to enter and accumulate in cells even at very low concentrations

Experimental Observation of Temperature-Driven Topological Phase Transition in HgTe/CdHgTe Quantum Wells

International audienceWe report on the comparison between temperature-dependent magneto-absorption and magnetotransport spectroscopy of HgTe/CdHgTe quantum wells in terms of the detection of the phase transition between the topological insulator and band insulator states. Our results demonstrate that temperature-dependent magnetospectroscopy is a powerful tool to discriminate trivial and topological insulator phases, yet the magnetotransport method is shown to have advantages for the clear manifestation of the phase transition with accurate quantitative values of the transition parameter (i.e., critical magnetic field B c)