Search

The carbonate leaching of scandium from the landfilled bauxite residue (red mud) of the Bogoslovsky Aluminum Plant (Russia) and samples of red mud (RM) after alkaline pretreatment has been investigated. The results of kinetic studies allowing to compare and evaluate the effectiveness of different conditions and intensification factors in the process of scandium leaching from RM in carbonate/bicarbonate media are presented. It was determined that for 2.0 mol L–1 Na2CO3 leaching solution ultrasonic treatment under gas (CO2) carbonation conditions in the pH range of 9.5–10.0 allows reducing the scandium leaching time by two times and reaching 40–45% scandium extraction. Leaching of RM in carbonate/bicarbonate media is accompanied by secondary processes (adsorption, hydrolysis, and coprecipitation) leading to a decrease in scandium extraction. The obtained results allow improving understanding of scandium chemical behavior in complex aqueous carbonate/bicarbonate systems and can be used for the optimization of the alternative carbonate process for scandium extraction from RM.

It is possible to increase the efficiency of using fossil fuels and to reduce thermal emissions into the environment and the emission of hazardous greenhouse gases by using thermotransformers (TTs) that utilize low-potential waste heat originating from man-caused sources to heat water for heating and hot water supply (HWS). As the main sources of low-grade waste heat, we have considered water circulation systems in heat power and industry as well as waste smoke fumes in boiler houses. The utilization of smoke fume heat (including latent) is the most relevant type of energy saving and of primary fuel saving, which additionally includes environmental benefits implemented by means of reducing nitrogen oxide emission. This paper proposes a scheme for the profound utilization of the heat obtained from combustion products of gas boilers using a condensation heat exchanger-utilizer and a lithium bromide absorption heat pump (LBAHP) with two-stage absorption. The analysis of the efficiency of this technology is carried out and the prospects for its implementation in gas boiler houses in Russia are considered. Studies have shown the feasibility of using LBAHP with two-stage absorption at existing large power facilities (thermal power from 116.3 MW and greater) and at small autonomous gas boiler houses (thermal power lower than 116.3 MW). The theoretical transformation ratio of LBAHP with profound utilization of smoke fumes amounts up to 1.71, whereas the saving of primary fuel in LBAHP amounts to 40% as to compared to a hot-water gas boiler. The economic effect of LBAHP significantly increases if it is used in the mode of a chilling machine for technological cooling and air conditioning in the warm season.

The liquid–liquid extraction, recovery of Np(VI) and Np(V) from the solution of Na2CO3 by methyltrioctylammonium carbonate in toluene was investigated. By the graphic slope analyses method, as well as by recording of absorption spectra for obtained solutions and method of calculated determination of solution properties taking into account water activity, composition was established for the carbonate complexes of Np(VI) and Np(V) being extracted, which, depending on extraction conditions, can be expressed by the following formulae’s: (R4N)2[NpVIO2(CO3)2], (R4N)3[NpVO2(CO3)2], (R4N)6[NpVIO2(CO3)4], (R4N)2[NpVIO2(CO3)2]·2(R4N)2CO3, (R4N)5[NpVO2(CO3)3], (R4N)7[NpVO2(CO3)4], (R4N)3[NpVO2(CO3)2]·(1–2)(R4N)2CO3, where R4N is the quaternary ammonium cation. The results have been obtained in the experiments, has much interest both in the field of alkaline radioactive waste management and with respect to their usage for extraction of transuranium elements during reprocessing of alkaline radioactive waste, as well as for liquid–liquid extraction purification of uranium and plutonium from admixtures of fission products. These techniques are used within the framework of a new alternative method for reprocessing of spent nuclear fuel in carbonate media the CARBEX (CARBonate EXtraction) process.

The heat of combustion and the enthalpy of formation of 7,7′-bis(terfurazan[3,4-b:3,4′-d:3″,4″-f]azepine (I) and 1,1′-dioxide-7,7′-bis(terfurazan[3,4-b:3,4′-d:3″,4″-f] azepine (II), were experimentally determined. Product I was studied by X-ray diffraction analysis, and its crystallographic characteristics were determined. The efficiency of using compounds I and II as components of solid composite propellants was analyzed, and the type of compositions in which they are more effective than HMX was determined.

The heat of combustion and enthalpy of formation of bis(4 $$''$$ -nitro[3,3 $$'$$ :4 $$'$$ ,3 $$''$$ ]terfurazan-4-yl)-diazene (DNFNF) and (bis(4 $$''$$ -azido-[3,3 $$'$$ :4 $$'$$ ,3 $$''$$ ]terfurazan-4-yl)-diazene (DAzFNF) were first experimentally determined. It is found that the energy increment for replacing the nitro group with an azide group in the furazan cycle averages 290 kJ/mol and is close to the increment for replacing NO2 with N3 in trinitroethane. The dependence of the energy parameters of metal-free rocket propellants based on a mixture of ammonium perchlorate and DNFNF or DAzFNF with an active binder on the content of the high-enthalpy component in the formulation was studied by thermodynamic analysis.

Liquid–liquid extraction (LLE) of microamounts of americium(III) from Na2CO3 and Na2CO3–H2O2 aqueous solution using methyltrioctylammonium (MTOA) carbonate in toluene has been studied. The distribution ratio of americium(III) into the organic phase can reach values of > 200 from aqueous phases of dilute Na2CO3 and H2O2. With an increase in concentration of Na2CO3 and H2O2 the value of distribution ratio of americium(III) decreases. The stoichiometry of the extracted species of americium(III) was determined on the basis of the slope analysis method. The extracted species are R4N[Am(CO3)2] and (R4N)3[Am(CO3)3], where R4N is MTOA.

The present work develops a novel unified approach to describe the crystal structure of orthorhombic martensite (α′′) in Ti alloys independent of chemical composition. By employing a straightforward yet highly instructive solid sphere model for the basic tetrahedral structural unit the crystal structures involved in the β ↔ α′′/α′ martensitic transformation are categorized into several intermediate configurations. Importantly, a new metric is introduced, δ, which unambiguously characterizes the atomic positions inside the orthorhombic unit cell depending on unit-cell geometry. Furthermore, the exclusive use of relative quantities to describe unit-cell geometry and atom positions renders the approach developed herein independent of alloy content. In this way, shortcomings of commonly suggested structural metrics for α′′ are eliminated. Subsequently, the novel methodology is applied to analyse and compare the crystal structure of α′′ across a broad range of Ti alloys based on experimentally measured unit-cell parameters. From this analysis it emerges that a large fraction of structural configurations along the b.c.c.-Cmcm-h.c.p. transformation path is not observed in quenched alloys. The threshold between the not-observed and the remaining well observed configurations is identified with an ideal Cmcm crystal structure, relative to which the experimentally found α′′ is compressed along its c axis. © 2021 International Union of Crystallography. All rights reserved. 0836-2020-0020 The following funding is acknowledged: State Assignment of Russian Federation (grant 0836-2020-0020).

Many current-generation biomedical implants are fabricated from the Ti-6Al-4V alloy because it has many attractive properties, such as low density and biocompatibility. However, the elastic modulus of this alloy is much larger than that of the surrounding bone, leading to bone resorption and, eventually, implant failure. In the present study, we synthesized and performed a detailed analysis of a novel low elastic modulus Ti-based alloy (Ti-28Nb-5Zr-2Ta-2Sn (TNZTS alloy)) using a variety of methods, including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and tensile test. Additionally, the in vitro biocompatibility of the TNZTS alloy was evaluated using SCP-1, SaOs-2, and THP-1 cell lines and primary human osteoblasts. Compared to Ti-6Al-4V, the elastic modulus of TNZTS alloy was significantly lower, while measures of its in vitro biocompatibility are comparable. O2 plasma treatment of the surface of the alloy significantly increased its hydrophilicity and, hence, its in vitro biocompatibility. TNZTS alloy specimens did not induce the release of cytokines by macrophages, indicating that such scaffolds would not trigger inflammatory responses. The present results suggest that the TNZTS alloy may have potential as an alternative to Ti-6Al-4V.

The research demonstrates microstructural changes and development of specific texture in Ti-6Al-4V specimens produced by electron beam melting (EBM) under different conditions. The effect of two factors, namely, raw material (powder) recycling and hot isostatic pressing (HIP), on the EBM produced samples structure and properties, has been explored. The as-printed and treated samples were investigated using electron backscattered diffraction (EBSD) analysis. Modification of mechanical properties after the EBM and HIP are explained by the EBSD data on microstructural phenomena and phase transformations. The work is devoted to assessing the possibility of reusing the residual titanium alloy powder for the manufacture of titanium components by the combination of EBM and HIP methods. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. Acknowledgments: The experiments on additive manufacturing were conducted in the frame of the Advanced Additive Titanium Development AATiD Consortium. This study was supported by the State Assignment of Russian Federation, grant no. 0836-2020-0020 and partly done within the State Assignment on theme “Pressure”.

The chemical properties of 3-amino-4-[5-(chloromethyl)-1,2,4-oxadiazol-3-yl]furazan were scrutinized: acylation of the amino group and its oxidation to azo and nitro groups, reactions of the chloromethyl group with N- and S-nucleophilic reagents, as well as reactions of transformation of the 1,2,4-oxadiazole ring.

The extrusion process advantage of agricultural raw materials processing into food and feed over traditional technologies is the high specific productivity, energy efficiency and versatility of use. The presence of a large number of control factors and influence on the raw materials quality, such as operating parameters and structural elements, make extrusion a difficult reproducible process when scaling or moving from one installation to another. But this aspect is the reason for the maximum flexibility of extrusion systems and the possibility of their continuous improvement. One of the ways for the extrusion technology development is the improvement of equipment and design solutions in the field of energy saving. Investigations of the thermoplastic extrusion process of wheat grinding with the application of the recovery of steam heat generated by a special configuration of screw elements and its degassing with the feeding into the processed material were carried out in the work. The modernized extruder Werner & Phleiderer Continua 37, supplemented by a developed recuperative unit and a steam line, was used to achieve this goal. An assessment of changes in energy consumption during steam recovery was carried out. The physicochemical properties of the experimental and control samples of wheat grain extrudates obtained under various operating conditions were investigated and determined. It was found out that the steam recovery mode is a statistically significant reason for increasing the humidity of the extruded product from 3.8 to 5.0 bulk density - by 15% relative to the mode without recovery. A decrease in the explosion coefficient and the water-holding capacity of the extrudates during operation in the regenerative mode of extrusion was noticed. The presented method with additional thermal effects on the processed raw materials allows us to expand the technological capabilities of the process of thermoplastic extrusion in obtaining products of various functional and technological purposes.

The concept of a new method, the CARBEX (CARBonate EXtraction) process, was proposed for reprocessing of spent uranium oxide fuel. The proposed process is based on use of water solutions of Na2CO3 or (NH4)2CO3 and solvent extraction (SE) by the quaternary ammonium compounds for selective recovery and purification of U from the fission products (FPs). Applying of SE allows to reach high degree of purification of U from FPs. Carrying out the processes in poorly aggressive alkaline carbonate media leads to increasing safety of SNF's reprocessing and better selectivity of separation of lanthanides and actinides. Moreover carbonate reprocessing media allows to carry out a recycling and regeneration of reagents. We have been done laboratory scale experiments on the extraction components of simulated voloxidated spent fuel in the solutions of NaOH or Na2CO3–H2O2 and recovery of U from carbonate solutions by SE method using carbonate of methyltrioctylammonium in toluene. It was shown that the purification factors of U from impurities of simulated FPs reached values 103–105. The received results support our opinion that CARBEX after the further development can become more safe, simple and profitable method of spent fuel reprocessing. Keywords: Simulated spent nuclear fuel, Simulated fission products, Oxidative dissolution, Solvent extraction, Quaternary ammonium compounds

Interesting results are obtained using a setup with electron-neutron detectors (EN-detectors) developed for the PRISMA (PRImary Spectrum Measuring Array) project to study extensive atmospheric showers. A small installation of four EN-detectors (PRISMA-YBJ) has been in operation for three and a half years on the Earth’s surface in Tibet, 4300 m above sea level, constantly measuring the natural flux of thermal neutrons. Neutrons are produced in soil during (α, n)-reactions with naturally radioactive α-particles, mainly from the decay of radon and daughter heavy nuclides. The neutrons are thermalized in the medium and, once in equilibrium with it, become sensitive to its state. They then can indicate many geophysical processes in the crust, including earthquakes. Results illustrating the sensitivity of EN-detectors to earthquakes are considered.

Red Muds (R.M.) – waste of bauxite reprocessing by the Bayer's method include many rare elements, such as Gallium, Titanium, Zirconium, Rare Earth Elements and Scandium, concentration of which in its reached 130 g/t. In the problem solving of Scandium extraction from R.M. get a two directions: immediate leaching of Scandium from R.M. and in passing Scandium recovery under complexing processing of R.M. The method of carbonate leaching of Scandium from R.M., which was work out in Institute of Solid State Chemistry Russian Academy of Sciences Urals Branch, include saturation by carbon dioxide of alkaline solutions, obtained after water process of R.M. and allow up to 20 % Scandium recovery in solutions. It is not effective for work out of technological scheme of R.M. processing. In recent paper, the chemical aspects of carbonate leaching of Scandium from R.M. in heterogeneous systems solid – liquid – gas carbon dioxide were investigated to determine of conditions for more Scandium recovery from R.M. It was shown, that Scandium leaching by aqueous sodium solutions without carbon dioxide gives small recovery yield and accompanied by alkaline hydrolysis under high pH in concentrated Na2CO3 solutions. Under saturation by carbon dioxide of carbonate R.M. pulp, the hydrolytic polymerization of hydroxocarbonates of Scandium and Aluminum in presence of carbonic acid proton take place. In the both process secondary precipitates are settle down and reduce of Scandium recovery yield. For increase of Scandium recovery from R.M. it is necessary to exclude the secondary precipitates under carbonate leaching with saturation by carbon dioxide.

This article presents the results of field experiments to study the effect of organic and mineral fertilizers in various combinations and rates on yield and the main indicators of potato tuber quality in cultivation on various soils of Russia: in the Non-Chernozem Zone of the European part (in the Moscow, Smolensk, Vologda regions) and in the northern region in Central Yakutia and near Verkhoyansk, one of the coldest points of the Northern Hemisphere. It has been established that the use of effective fertilizer systems in various soil and climatic conditions is an important factor in increasing the potato yield, improving the tuber quality, increasing their starch content, and reducing nitrates. According to the research conducted, when combinations and rates of fertilizers in organo-mineral systems were optimized, potato yields significantly increased in relation to the control on sod-podzolic soils to 31–38 t/ha in the Non-Chernozem zone in the Central region and in the North-west region, to 20–22 t/ha in the north in the European parts, to 19 t/ha in marginal conditions on the permafrost taiga soils of Central Yakutia, and to 6–7 t/ha beyond the Arctic Circle. On the basis of experimental data, the parameters of environmentally safe fertilizer systems were established, ensuring that potatoes could be sustainably produced as the population’s most important food product.

Complexing processing of «red muds» (R.M.) - waste of bauxite reprocessing by the Bayer's method, is one of the important tasks of toxic industrial waste utilization. Studied the possibility of aluminum leaching from the R.M. which content reach 14 %, received from Bogoslovsky aluminum plant of JSC «Siberian-Urals Aluminium Company» by aqueous solutions of NaOH. The process was carried out at atmospheric pressure and temperatures near to the boiling point of leaching solutions with the utilization of the residual alkali. The time’s dependence of the aluminum leaching degree from the R.M. by aqueous solutions of NaOH passes through the maximum due to the formation of secondary precipitation of aluminum. The cause of secondary sedimentation is the interaction of silicon with aluminum with formation of insoluble aluminosilicates, for example, Nа2Аl2Si2O8·2Н2O. The conditions of leaching, under which the formation of stable aluminate solutions during the time do not form of secondary precipitations were established. The maximum achieved values of the aluminum leaching degree in autoclave-free conditions was reach 20-25 %. The removal of alkali and part of aluminum under the first stage of complexing processing of R.M. leads to their enrichment in iron. The cakes from aluminum leaching and next carbonate scandium leaching can be used for pyrometallurgical recovery of iron and slag, in which untreated elements are passed, including residual aluminum, scandium, sum of rare earth elements, titanium and zirconium. A significant decrease in the volume of slag opens more opportunities for further isolation their components by acidic methods.

The effect of machining conditions on the scandium leaching effectiveness from the wastes of wet magnetic separation of iron–titanium magnetites in sulfuric acid solution has been studied. It has been shown that the degree of recovery of scandium into sulfuric acid solution linearly increases with an increase in the degree of amorphization of specimens of wastes of wet magnetic separation.

Bis(4-nitrofurazan-3-yl)furazan (DNTF) and 3,4-bis(4-nitrofurazan-3-yl)furoxan (DNFF) have been studied as potential components of composite solid rocket propellants. Their heats of combustion and enthalpies of formation have been determined experimentally. X-ray diffraction analysis has shown that the DNTF and DNFF crystals are orthogonal with the same space group P212121. It has been found DNTF and DNFF are ineffective in rocket propellants with a hydrocarbon binder; however, when using DNTF for compositions without aluminum and with an active binder, it is easy to provide a specific impulse of 254.5 s at combustor and nozzle exit pressures of 40 and 1 atm, respectively, and at a density of 1.77 g/cm3, and when using DNFF, a specific impulse of 258 s at a density of 1.79 g/cm3.

Investigations were carried out on permafrost taiga soil in Central Yakutia in a field factorial experiment with a wide range of rates and combinations of cattle manure and mineral fertilizers. The advantage of an organo-mineral fertilizer system in N60P60K60 rates was shown against a background of 40 t of manure per hectare, which provides, under watering conditions, potato tuber yields of 18 t per hectare with starch content of 13.9%, which is 47.8% higher than in the control without fertilizer use. The yield of potatoes under the organic system with annual manure rate of 40 t per hectare was at the same level with the mineral system, but tubers contained more starch, 12.8%. It has also been established that organo-mineral and organic systems have a positive effect on the agrochemical properties of the soil, optimize its humus state and phosphate and potassium regimes. For the mineral fertilizer systems in rates of N60P60K60, the yield increment was significant, but it did not exceed 17.8% with a lower starch content in tubers, 11.5%, and a negative balance of humus, phosphorus, and potassium in the soil.

The potentiometric titration of a weakly basic carboxyl cation exchanger, obtained via alkaline hydrolysis of an acrylonitrile copolymer with divinyl benzene (degree of crosslinking, 12%) in a wide range of variation in a solution of рН (2–12) and NaCl (concentration 0.01, 0.1, 0.5, 1 М), is considered. The maximum ion-exchange capacity of the ion exchanger for Na+ is determined (10.10 ± 0.088 mmol/g of the dry mass) and found to be independent of the solution’s ionic strength. It is established that in the investigated range of NaCl concentrations and рН, the acid–base balance is adequately described by Gregor’s equation. The parameters of this equation are calculated as a function of the NaCl concentration: рKа = 8.13 ± 0.04, n = 1.50 ± 0.02 for 0.01 М; рKа = 6.56 ± 0.04, n = 2.60 ± 0.07 for 0.1 М; and рKа = 5.66 ± 0.6, n = 2.62 ± 0.06 for 0.5 and 1 М. It is shown that to describe the acid–base balance correctly within the proposed model we must estimate the adequacy of the experimental and calculated values of the ion exchanger’s capacity at each рН value according to the calculated parameters of Gregor’s equation.

The standard enthalpies of combustion and formation of 7H-tris([1,2,5]oxadiazolo) [3,4-b:3′,4′-d:3″,4″-f]azepine, its bimolecular crystal with the γ-polymorph of CL-20, and the γ-polymorph of CL-20 have been experimentally determined. The standard enthalpies of formation of the bimolecular crystal and an equimolecular mechanical mixture of γ-CL-20 with azepine differ by less than 12.8 kJ/mol. This small difference is validated by quantum chemical calculations. It has been experimentally found that the presence of azepine in the bimolecular crystal inhibits the thermal decomposition of γ-CL-20 and increases the thermal stability of γ-CL-20 in the bimolecular crystal as compared to original γ-CL-20.

Potentiometric titration of weak base anionite (the degree of crosslinking was 12–16%) was performed within the pH range of 2–12 and NaCl concentration range of 0.1–1.0 mol/L. The maximum ionexchange ability against HCl does not depend on the solution ionic strength and is 6.50 ± 0.12 mmol/g of dry solid matter. It was shown that the process of acid–base equilibrium can be adequately described by the Gregor equation within the studied stock electrolyte concentration and pH ranges. Two type of groups were discovered in anionite. The ionization constants of these groups differ by three orders of magnitude. The existence of amino groups of different nature was proved by the data obtained by functional analysis; it was estimated that the acidity of these groups decreases as NaCl concentration increases.

Samples of VT23 β-metastable titanium alloy quenched from temperatures in a range between critical and β-transus were studied in situ during heating on X-ray diffractometer. The anisotropy of orthorhombic martensite lattice was investigated. Abnormal behavior of «b» lattice spacing, which demonstrated a negative value of thermal expansion, has been revealed.

The problem of stress-strain state upon compression of implant of titanium alloy with cellular architecture was formulated by means of ABAQUS software and finite element analysis. The volume of the material was segmented on the unit cells characterized by specific configuration. The boundary conditions and physical equations were stated to describe the correlation between stresses and strains. The calculations of stress values, area reduction and mean stress were performed. The increased strain rates were revealed in horizontal pore cell walls. Joint simulating of several individual unit cells was provided. Zone seeing tensile stresses were observed in the segment of radius of the unit cell. The estimation of threatening sections location of the construction was conducted.

The extraction of scandium from solutions of the waste of sulfuric-acid leaching from the magnetic separation of titanomagnetites via toluene solutions of equinormal mixtures of D2EHPA and MTAA sulfate has been studied. The conditions for scandium quantitative extraction from solutions containing 2.0–3.0 mol/L of H2SO4 and 5–10 mg/L of Sc have been determined with the saturation of the organic phase up to 300–450 mg/L with respect to Sc. It has been shown that the two-stage reextraction of scandium from the saturated organic phase by alkaline-carbonate solutions containing 12 wt % of Na2CO3 + 1 wt % of NaOH allows scandium and accompanying impurities of nonferrous and rare metals to be completely converted into a solid that forms a rough scandium concentrate containing 4–8 wt % of Sc, which can be used to prepare high-purity scandium oxide.

The kinetics of the Pu(VI) reduction with carbohydrazide in nitric acid solutions was studied by spectrophotometry. The reaction rate increases with increasing carbohydrazide concentration and temperature and decreases with increasing HNO3 concentration. The reaction order with respect to Pu, carbohydrazide, and HNO3 is 1, 2.3, and–3, respectively. The activation energy of the reaction is 111 kJ mol–1. The final reduced Pu form is Pu(III), with Pu(V) being an intermediate.

A practical and scalable scheme for the synthesis of 5-(4-aminofurazan-3-yl)-1-hydroxytetrazole was developed, starting from 4-aminofurazan-3-carboxylic acid amidoxime. New methods were proposed for the synthesis of 1-hydroxy-5-(4-nitrofurazan-3-yl)-tetrazole and 5-(4-azidofurazan-3-yl)-1-hydroxytetrazole.

We describe an effective scheme for the synthesis of a new energetic compound – 3-azido-4-(2H-tetrazol-5-yl)furazan from 4-amino-N'-hydroxyfurazan-3-carboximidamide. The structure of 3-azido-4-(2H-tetrazol-5-yl)furazan was proved by 1Н and 13С NMR spectroscopy, mass spectrometry, and X-ray structural analysis. 3-Azido-4-(2H-tetrazol-5-yl)furazan crystallized in monoclinic syngony, space group Р21/n, monocrystal density d 1.953 g·cm–3 (100 K). According to differential scanning calorimetry data, 3-azido-4-(2Htetrazol-5-yl)furazan melts at 103.3°С, while the maximum of thermal decomposition exotherm was observed at 185.6°С. The sensitivity of 3-azido-4-(2H-tetrazol-5-yl)furazan to impact (2 kg, 25 cm, 36% explosion frequency) and to friction (1450 kg·cm–3 lower limit) was at the level of pentaerythritol tetranitrate. The salts of 3-azido-4-(2H-tetrazol-5-yl)furazan with ammonia and guanylurea were also obtained and characterized.

The aim of this study was to compare the effects of sulfated fucopolysaccharides isolated from Fucus vesiculosus on HeLa G-63, Hep G2, and Chang liver cells. Native fucoidan F3 and two fractions (F3-0.5 and F3-1) obtained by anion-exchange chromatography were analyzed using chemical methods and IR spectroscopy. It was demonstrated that F3 and F3-1 are characterized by a higher content of sulfates, location of sulfo groups mostly at the C4 atom of fucose residue, and low content of uronic acids inhibited cell proliferation. Human liver carcinoma Hep G2 appeared to be the most sensitive to fucoidan, whereas nonmalignant human Chang liver cells were the least sensitive.

The extraction of U(VI), Ce(IV), La(III), Nd(III), Sm(III), and Y(III) from an aqueous solution of Na2CO3 (0.25 mol/L) resulting from oxidative dissolution of U(IV) in the presence of H2O2 into a solution of methyltrioctylammonium carbonate (0.25 mol/L) in toluene. It was found that βU(VI)/Ln(III) values vary from ~8 to 3290 as the O : W ratio changes from 2 : 1 to 10 : 1, while βU(VI)/Ce(IV) varies from ~1.5 to 10, which allows for the extraction separation of U(VI) from Ce(IV) in a 8- to 10-stage counter-current extraction cascade and from Ln(III) in 2- to 3-stage cascade under the same conditions.

Special features of formation of structure and properties of seamless pipes from medium-carbon low-alloy steel for oil and gas applications are considered and associated with chemical inhomogeneity of the metal of the pipes.

The electronic absorption bands of extracts of the Na4[UO2(O2)(CO3)2] complex with methyltrioctylammonium (MTOA) carbonate were assigned taking into account hydration, hydrolysis, dissociation, polymerization, and ligand exchange, which occur in aqueous and organic solutions. It was shown that the extractable compound, (R4N)4[UO2(O2)(CO3)2], present in low concentrations in the organic phase partly dissociates by one step to give the (R4N)3[UO2(O2)(CO3)2]– anions, while at high concentrations, it is converted to polynuclear complex.

A convenient preparation method was developed for 4″-nitro-3,3′:4′,3″-ter-1,2,5-oxadiazol-4-amine by substituting one nitro group of 4,4″-dinitro-3,3′:4′,3″-ter-1,2,5-oxadiazole at treating with equivalent quantity of ammonia in solvents of low polarity. In the reaction of the obtained amino-nitro derivative with N- and О- nucleophiles depending on the reaction conditions and the nucleophile nature either substitution of the nitro group occurs for the nucleophile residue to form 4″-alkoxy-, azido-, hydraznyl- or mono- and dialkylamino-[3,3′;4′,3″]-ter(1,2,5-oxadiazol)-4-ylamines, or the compound suffers an intramolecular cyclization affording 7Н-tri-1,2,5-oxadiazolo[3,4-b:3′,4′-d:3″,4″-f]azepines.

On the basis of consideration of dissociation, hydration, association, and ligand exchange, the assignment of absorption bands in the electronic spectra of aqueous solutions of the Na4[UO2(O2)CO3)2] complex has been performed. It has been demonstrated that the absorption in the range 190–400 nm is caused by the oxygen atoms of the O22- and CO32- groups and hydration water molecules of dissociated and neutral complex species Na3[UO2(O2)(CO3)2]–, Na2[UO2(O2)(CO3)2]2–, and Na4[UO2(O2)(CO3)2].

3,4-Bis(4-aminofurazan-3-yl)furazan was used to obtain a new energetic terfurazan derivative, namely, bis(4″-nitro[3,3’:4’,3″]terfurazan-4-yl)diazene, the sensitivity of which to mechainical impact was found to be close to that of HMX. The new compound was characterized by NMR spectroscopy, mass spectroscopy, IR spectroscopy, X-ray crystallography, and elemental analysis.

We report on Ga 2 O 3 deposition on c-plane sapphire substrates by hydride vapour phase epitaxy using metallic gallium, hydrogen chloride and dry air as precursors. High deposition rate up to 250 µm/h has been realized. As confirmed by X-ray diffraction and micro-Raman measurements, produced films consisted of pure monoclinic β-Ga 2 O 3 phase and were (−201) oriented. The full width at half maximum (FWHM) for (−201) rocking curve was decreasing with increasing GaCl flow. The narrowest FWHM of 20 arcmin has been detected.

Red mud are industrial large-scale toxic wastes of bauxite ore processing according to the Bayer method. They contain macrocomponents such as iron, aluminum, calcium, silicon, as well as a number of the most valuable and critical metals (microcomponents): scandium, gallium, germanium and rare earth elements (REEs), which are used in modern high-tech industry. Due to the relatively high content of scandium and REEs, red mud can be considered as a promising secondary source. Significant amounts of accumulated red mud and new flows of this waste entering the slime storage facilities need to be processed to obtaine the required valuable products. Development of complex reprocessing approach play an important role in addressing the problem of the elimination of red mud as toxic waste. Within the framework of this subject, the report considers the concept of complex reprocessing of Bogoslovsky Aluminum Plant (Russia) red mud, which includes the extraction of aluminum, scandium, REEs, zirconium and the production of iron-containing concentrate for ferrous metallurgy. The use of low-aggressive carbonate media and carbonation method using carbon dioxide gas characterizes this approach as more environmentally and technologically safe. The development of effective technology for utilization of red mud will not only provide a source of critical raw materials, but also solve the global environmental problem.

Some unexpected sporadic increases of an environmental radioactive background have been recorded at mountain level at Baksan Neutrino Observatory (BNO, 1700 m above sea level) using electron-neutron detectors (en-detectors), which could be explained by radioactive aerosol enhancements. The large area inorganic scintillator en-detectors developed for cosmic ray study are continuously monitoring environmental thermal neutron fluxes at various geophysical conditions. Application of the pulse shape discrimination method allows us to select and separately measure both thermal neutrons and radioactive beta-decay nuclides being products of radon decays in air (mostly Rn-222 and Rn-220). There are two en-detector setups running now at BNO, one deep underground while another one at surface. Both installations had recorded some strange sporadic increases of radioactive nuclides in air. In this paper, we present results and the most probable explanation of the significant increases joint by radioactive aerosols production but caused by different reasons: Baksan river floods or nearby underground experiment with powerful Cr-51 radioactive source.

Additive technologies are getting widely used in orthopedics due to the opportunity of full modelling of complex cellular structures and producing personalized implants. Titanium and its alloys are still the main material used for metallic implants manufacturing. In this study microhardness and Ca/P ratio of bone tissue surrounding the implant were investigated. By means of ABAQUS software titanium porous structure implants were designed. Their biomechanical properties were close to biomechanical properties of trabecular bone tissue. Direct metal laser sintering (DMLS) was used to manufacture implants from Ti-6Al-4V titanium alloy. They were augmented in trabecular bone defects of Chinchilla rabbits for 6, 12 and 25 weeks. The samples were examined by scanning electron microscopy (SEM) in a FEG SEM ZEISS CrossBeam AURIGA and the Ca/P ratio was calculated using the accompanying Oxford Inca software. Vickers hardness test method was performed for microhardness. It was shown that there was a significant increase in both mineral and mechanical properties of bone samples with an increase of observation period. The results found in this study illustrate a distinct relationship between the mineralization parameter of bone tissue and its microhardness (r = 0.808, r2 = 0.65). We hereby acknowledge the support of the Ministry of Science and Education of the Russian Federation, in accordance to the decree of the Government of April 9, 2010, №218, project number 03.G25.31.0234. The work was carried out using the laboratory equipment ”Structural methods of analysis and properties of materials and nanomaterials” of the Center of Ural Federal University.

Reactions of oxepino[2,3-c:4,5-c′:6,7-c″]tri(1,2,5-oxadiazole) with hydrazine, aliphatic amines, azide- and methoxide aniones, occurring with the opening of ether cycle and generation of 4″-substituted 3,3′:4′,3″-ter-1,2,5-oxadiazol-4-ols, is a convenient synthetic path to unsymmetrically substituted terfurazanes.

An alternative method has been developed for the preparation of 4-R-furazan-3-carboxylic acid amidrazones (R = OMe, NH2, substituted amino group) by reductive opening of 1,2,4-oxadiazole ring in 4-R derivatives of (1,2,4-oxadiazol-3-yl)furazans by the action of hydrazine. The starting 1,2,4-oxadiazoles were synthesized from 4-aminofurazan-3-carboxylic acid amidoxime. Some chemical properties of the obtained compounds were studied.

Results of investigation of the dispersed, phase, and chemical compositions of products of plasma dynamic synthesis in a high-speed pulsed jet of copper-containing electroerosive plasma flowing into a closed volume with the air atmosphere are presented. Products of synthesis are investigated by the methods of x-ray phase and thermal analyses, electron microscopy, and IR spectroscopy. The structure of the synthesized powder includes metal copper, Cu2О and CuO copper oxides, and hydrated copper hydroxide Cu(OH)2·Н2О. Results of investigations of structural changes of the synthesized products during heating in vacuum and air are presented.

The effect of polydisperse fucoidans from brown algae Fucus vesiculosus on Hep G2 and Chang liver cells was studied. Despite the high molecular weight and polydispersity, these fucoidans exhibited antitumor activity, whereas the difference in the inhibitory effects on cell proliferation between the native and the partially hydrolyzed fucoidans was not statistically significant. Fucoidans were internalized by cells of both cell lines through endocytosis, with Chang liver cells metabolizing fucopolysaccharides more rapidly compared to the Hep G2. In both cell lines treatment with fucoidans was shown to induce apoptosis and autophagy, with apoptosis more pronounced in Hep G2 cells, whereas autophagy - in Chang liver cells.

This article is devoted to the development of the production of 99Mo used in nuclear medicine. The stages in the development of the production of 99Mo and molybdenum-technetium generators are shown. Production has increased several-fold over the period 2009–2013 and meets the demand of domestic nuclear medicine. The problem of recycling the uranium from an irradiated target after 99Mo is extracted from the target is important and strongly influences the price of 99Mo. A technology for reprocessing uranium-containing tailings with the uranium obtained being returned into the 99Mo production cycle has been developed at the Scientific-Research Institute for Physical Chemistry. This has eliminated the need to purchase expensive high-enrichment uranium for targets and has made it possible to use the uranium remaining from the reprocessing of irradiated targets.

The Severskii Pipe Plant has developed a technology for obtaining continuous-cast semifinished products made of pipe steels alloyed with cerium. Use of the technology makes it possible to homogeneously distribute the REM over the volume of the steel and give it satisfactory castability on continuous casters operating in the automatic regime. Up to 900 tons of liquid steel can be cast in a single series with the use of this technology.

Features of structural and phase transformations, and also formation of a set of properties of Cr–Mo–V pipe steels are studied. Heat treatment regimes are developed for high-strength casing pipes for corrosion resistant application. Prospects are considered for application of computer simulation of production processes in a Visual Weld 9.0 program for developing and adjusting oil and gas pipe heat treatment regimes.

The crystal structure of the bimolecular crystal of CL-20 with new promising highly energetic compound 7H-tris-1,2,5-oxadiazolo[3,4-b:3′,4′-d:3″,4″-f] azepine is obtained and studied.

The results from a 29-month investigation into the EAS electromagnetic component using the PRISMA-32 array are presented, notably for the central density spectrum and energy deposit spectrum. The array consists of 32 en-detectors in which specialized inorganic scintillators (SL6-5 phosphorus composition) based on silver-activated zinc sulfide (ZnS) with LiF enriched to 90% 6Li (ZnS(Ag) + 6LiF) are used as detecting layers. The possibility of detecting the electromagnetic component using a thin scintillation neutron detector with the multiple passage of charged particles is shown. The experimental data are compared to the results from simulations.

This paper describes a mathematical model of the learning process suitable for studies of conditioning using the proboscis extension reflex (PER) in honey bees when bees are exposed to agrochemicals. Although procedural variations exist in the way laboratories use the PER paradigm, proboscis conditioning is widely used to investigate the influence of pesticides and repellents on honey bee learning. Despite the availability of several mathematical models of the learning process, no attempts have been made to apply a mathematical model to the learning curve in honey bees exposed to agrochemicals. Our model is based on the standard transfer function in the form Y=B3 e(-B2 (X-1)) +B4(1-e(-B2 (X-1))) where X is the trial number, Y is the proportion of correct responses, B2 is the learning rate, B3 is readiness to learn, and B4 is ability to learn. We reanalyze previously published data on the effect of several classes of agrochemicals including: (1) those that are considered harmless to bees (e.g., pymetrozine, essential oils, dicofol); (2) sublethal exposure to pesticides known to harm honey bees (e.g., coumaphos, cyfluthrin, fluvalinate, permethrin); and (3) putative repellents of honey bees (e.g., butyric acid, citronella). The model revealed additional effects not detected with standard statistical tests of significance.