X-ray Phase Research Articles

Получение порошковых углеродных композитных наноматериалов термическим разложением ароматических карбоксилатов Fe (III)

The article discusses the principal methods for obtaining carbon composite nanomaterials and highlights the thermolysis method as one of them. In order to understand the essence of thermal decomposition processes as a method for synthesis of carbon nanomaterials, aromatic iron(III) carboxylates have been considered. These are iron(III) 8-hydroxyquinolinate, benzoate, salicylate, phthalate, and p-aminobenzoate. The article discusses the procedure for the synthesis of these iron(III) carboxylates under standard conditions in detail. The thermal decomposition process was carried out in two media (air as oxidizing one and argon as neutral one) to compare the obtained products. For a detailed study of the processes of decomposition of iron(III) carboxylates, the thermal analysis methods (TG and DSC) were used on a Netzsch 449 Jupiter synchronous thermal analyzer. In order to study the morphology and composition of the products, X-ray phase analysis, optical and scanning electron microscopy, as well as X-ray fluorescence microanalysis were used. We used a Rigaku Ultima IV X-ray diffractometer and a scanning electron microscope with a Jeol JSM-7001F elemental microanalysis attachment. Based on the obtained results, the expected formulas of the initial iron(III) carboxylates were calculated. The mechanisms of the processes occurring during the thermal decomposition of iron(III) aromatic carboxylates were also proposed. For a more accurate determination of the composition of the synthesized iron(III) carboxylates and a more appropriate description of the processes of thermal decomposition of these salts, the corresponding aromatic carboxylic acids were also subjected to thermal decomposition. The appendix to the article contains the data for a more accurate interpretation of the results and a more detailed description of the thermal decomposition processes.

Synthesis and study sorption properties oligo(poly)-mer sorbents based on urea-formaldehyde and cyanuric acid

Using the Chem3D Pro program, some empirical and semi-empirical orbital properties of urea, formaldehyde, urea-formaldehyde and 1,1’,1”-((2,4,6-trioxo-1,3,5-triazinan-1,3,5-tri)-tris(methylene))triurea The length and angular relationships of the bonds, optimization and calculation of the energy of the molecule, quantum chemical calculations of the studied compounds using the MM2 method are shown. The resulting samples were examined using IR spectroscopy and X-ray phase analysis. Also, in this article, the dependence of the sorption of some d-metals on the sorbent based on cyanuric acid on the pH environment was studied and the results were presented. In sorption, the optimal pH size corresponds to the pH size of the formation of the acidocomplexes of the respective metals. Accordingly, the level of sorbation of the ions of the metals studied (SA+MFO (III)) in the sorbent increases in the following series: Mn (II) < Fe (II) < Co (II) < Ni (II) < Zn (II) < Pb (II) < Hg (II) < Cd (II) < Cu (II) < Ag (I).

Features of Hardening of Aluminosilicophosphate Binder in Cellular Concrete

Cellular phosphate concretes are used as an insulating material for some high-temperature aggregates due to their high temperature resistance, fire resistance and residual strength at the level of values after drying. The use of industrial waste in phosphate cellular concrete technology made it possible to improve some properties without reducing the application temperature. The paper shows that dispersed aluminosilicate waste from refractory production has sufficient activity (porization ability) to obtain a phosphate binder. The features of the hardening of an aluminosilicophosphate binder cured with dispersed metallic aluminum have been studied; the change in the phase composition of the cured binder after firing at different temperatures has been studied by differential thermal and X-ray phase analysis. It has been established that the developed aluminosilicophosphate binder makes it possible to obtain fireclay cellular concrete with an application temperature of up to 1400оC. A comparison of the changes in the phase composition for the developed aluminosilicophosphate composition and a pure aluminophosphate binder is performed. A shift in the temperature of the processes is noted in an upward direction for the aluminosilicophosphate binder, which is explained by the fact that silicon ions do not form independent phosphate compounds, but are embedded in the crystal lattice of aluminophosphates, changing their properties and shifting the intervals of phase transitions.

MAGNETOTHERMAL PROPERTIES OF COPPER FERRITE

In this work, we carried out the directed synthesis of copper ferrite (CuFe2O4) by co-precipitation from solutions with an excess of alkali at a temperature of 373 К. The methods of scanning electron microscopy and X-ray phase analysis were used to study the crystal structure and surface morphology of copper ferrite. The ratio of the characteristic peaks of the diffractogram was carried out in accordance with the JCPDS database. It is shown that copper (II) ferrite crystallizes in the structure of the cubic spinel. Microphotographs of the synthesized copper ferrite samples at different magnifications are given. It is established that ferrite particles consist of conglomerates of crystals with different sizes of individual grains. Their small scatter in size is observed. The average particle size is in the range of 100-200 nm. Using a dynamic heat flux differential scanning calorimeter, the temperature dependence of the heat capacity of copper ferrite samples was obtained in the temperature range of 273–373 K. Using an original microcalorimetric setup in the temperature range of 288–346 K and with a change in the magnetic field induction from 0 to 1.0 T, thermodynamic characteristics were obtained - the magnetocaloric effect (MCE) and the change in entropy (ΔS) during the magnetization of copper (II) ferrite. It was found that with an increase in the magnitude of the magnetic field, the magnitude of the MCE increases and decreases with increasing temperature. It was found that the temperature dependences of the magnetocaloric effect and specific heat have an extreme character. In the region of room temperatures (308–315 K), a maximum of the magnetocaloric effect and a minimum of the specific heat are observed. This previously unknown anomalous behavior of the magneto-thermal properties of copper II ferrite was discovered for the first time.

Diversity of sound production and hearing in fishes: Exploring the riddles of communication and sensory biology

My research in fish bioacoustics started in the mid-1980s and comprised the diversity in sound-generating mechanisms and sound production in various contexts such as dyadic contests. I worked on European freshwater and marine fish, but mainly on tropical fish from Southeast Asia (gouramis) and the Amazonian River system (pimelodid, doradid catfishes, piranhas). The diversity of sonic organs raised the question if general patterns of innervation of sonic muscles in vocal fishes exist. Different vocal (sonic) motor nuclei were identified in the brainstem and rostral spinal cord for pectoral and swim bladder vibration mechanisms. In addition, I wanted to find out if vocal fish differ from nonvocal species in hearing abilities. Measurements applying the auditory evoked potential technique revealed a large diversity of auditory sensitivities depending on the presence or lack of accessory hearing structures independently of sound production. Furthermore, I investigated the anatomy, ultrastructure of inner ears, and hearing enhancement by auxiliary hearing structures. Recently, we studied sound-induced motion of swim bladders, auditory ossicles, and otoliths using x-ray phase contrast imaging. A large part of my studies was carried out in cooperation with laboratories in the USA, Germany, Italy, Portugal, and Brasilia which made my research interesting.

К ВОПРОСУ ПОЛУЧЕНИЯ ФОРСТЕРИТСОДЕРЖАЩЕГО ЛИТЬЯ ИЗ ХВОСТОВ БОРОИЗВЛЕЧЕНИЯ И СТЕКЛОБОЯ ЭЛЕКТРОДУГОВЫМ СПОСОБОМ

The article investigates the characteristics of man-made waste in form of boron tailings (China) and cullet to establish the possibility of their joint use as a raw material composition in production stone forsteritecontaining casting by electric arc method. It studies of granulometric elemental, chemical and mineralogical composition of raw materials, using dispersion-gravimetric, Ultraviolet-Visible spectroscopic, microscopic, energy dispersion, as well as X-ray phase analyses. The study established true density, specific surface area, granulometric, elemental, chemical and mineralogical (XFA) compositions of raw materials and calculated modulus of acidity of the melt, which amounted to Mk = 2.04. It allows casting from two-component charge (tailings cullet) represented by percentage ratio of 70:30. In process of electric arc melting of the raw material composition, forsterite-containing stone casting was obtained, which is solidified melt of a given geometric shape made of forsterite (Mg2SiO4) in a glass phase. Thus, the conducted complex of studies testifies to the suitability of man-made waste represented by boron recovery tailings and cullet for obtaining a melt from them by electric arc method, with further production of forsterite-containing stone casting.

A STUDY ON PHYSICO-CHEMICAL PROPERTIES OF MODIFIED SULFUR CONCRETE

In this article, the polymerization reaction of elemental sulfur with organic modifiers is studied, and the optimal conditions of the modification process are presented. Also, the process of obtaining polymer sulfur concrete from modified sulfur is presented. Initially, elemental sulfur is heated to a temperature of 140-145 0C, aniline hydrochloride is added, and the temperature of the reaction is raised to 160 0C for 45 minutes. The average density of this obtained sulfur concrete sample was 2382 kg/m3. Sulfur-based concrete was obtained using the modified sulfur obtained in this process. Sulfur-based concrete was obtained by taking 56% sand, 14% ash, and 30% modified sulfur. Physico-chemical properties of sulfur concrete obtained based on modified sulfur and modified sulfur were studied and analyzed using X-ray phase analysis, IR-spectroscopy, scanning electron microscope, gamma-spectroscopy, and X-ray analysis. Also, the thermal analysis of modified sulfur-based concrete was studied using differential-thermal and thermogravimetric analysis. It was calculated that the average particle size d(nm) of the obtained polymer sulfur concrete is equal to 84.14 according to the Debaya-Sherrera equation.

Влияние длительного естественного старения теплоизоляционных минераловатных материалов на физико-химические и термические превращения

Purpose. The article studies physico-chemical and thermal transformations of mineral wool thermal insulation of natural ageing. The subject of the study is thermal insulation materials of natural ageing, and the object of the study is their physicochemical and thermal characteristics. The aim of the work is to establish physicochemical and thermal transformations of mineral thermal insulation of natural ageing. The research is aimed at identifying features of physico-chemical and thermal transformations of thermal insulation based on mineral fibers and organic binders in the ageing process. Methods. A set of precision physicochemical methods such as X-ray phase analysis (XRF), infrared spectroscopy and thermal analysis methods (TG, DTG, DSC) was used. Findings. The results of studying mineral thermal insulation (service life of 60 years) revealed characteristic changes in the structure of the material. The XRF method established that the ageing process of mineral wool materials is caused by occurring microdefects and disruption of material fibers structure organization. Changes in thermal insulation phase state have thermal fluctuation of kinetic nature of material mechanical destruction. The IR spectroscopy method identified changes in the areas of characteristic absorption bands: 2 800–2 200, 2 000–1 600 and 1 295–1 005 cm–1 caused by chemical destruction of organic binder in mineral thermal insulation. The nature of thermal transformations of the material was established, a tendency towards a decrease in the threshold temperatures for mass loss start due to destructing polymer binder was revealed. It is noted that natural ageing may result in loss of fire resistance of thermal insulation systems, as well as in intensificating smoldering combustion of thermal insulation. Research application field. The results are of interest to builders, designers, fire safety engineers and can be used in regulatory and technical as well as in reference literature on fire safety. Conclusions. During the ageing process irreversible physical and chemical changes occur in the structure of thermal insulation, leading to loss of thermal stability of the material and to a possible increase in the intensity of latent smoldering combustion. Technical obsolescence of the material leads to decreasing fire resistance limits of various thermal insulation systems due to loss of thermal insulation capacity and integrity.

Синтез и свойства каталитических хемосорбентов на основе оксида титана

In this work, we studied the synthesis and properties of catalytic chemisorbents based on titanium dioxide with additions of ZnO and γ-Al2O3. The goal was to obtain chemisorbents with desired performance characteristics and evaluate their potential in destructive hydrogenation of organo-sulfur compounds. Their sulfur capacity and hydrogenating capacity were measured by the static method with carbon disulfide absorption. Textural and morphological characteristics were deter-mined with the use of X-ray phase analysis, low-temperature nitrogen adsorption/desorption, and scanning electron microscopy. It was also found that addition of alumina did not give additional reflections on the X-ray pattern, in contrast to introduction of zinc oxide. It was found that addi-tion of zinc oxide significantly increased the values of the specific surface area, many times more than expected, according to additivity principle. Conversely, addition of alumina did not give the expected increase in surface area. The one and the other were explained through active interaction of phases. The ratios of components for obtaining chemisorbents with optimal strength properties were established. It was found that a composite consisting of titanium and aluminum oxides was more resistant to sulfurization than one with additions of zinc oxide. SEM and low-temperature ni-trogen adsorption/desorption methods confirmed the mesoporous structure of the studied samples, while the sample containing gamma alumina showed a more pronounced desorption branch to-gether with the surface consisting of spherical formations arranged in a regular order. The sample with zinc oxide had slit-like pores in its volume. Hydrogenation of thiophene with gaseous hydro-gen was carried out for the studied composites. Chromatographic analysis of the resulting product was performed. It was proven that composites based on titanium, zinc, and aluminum oxides not only had sorption properties with respect to organosulfur compounds, but also catalyzed their de-structive hydrogenation. Thus, it was established that the studied samples were chemisorbents. The study provides insight into synthesis and properties of catalytic titania-based chemisorbents, high-lighting the influence of additives and their potential for organosulfur reduction reactions.

Electrical conductivity of nanofluids based on water and Cu-C nanoparticles synthesized by the electric arc method

In this work, electric arc synthesis was carried out by sputtering a graphite electrode with copper powder in a helium environment at a pressure of 12 Torr, resulting in the production of copper nanoparticles coated with carbon, with an average size of 6 nm. The synthesized material was characterized by transmission electron microscopy, Raman spectroscopy, and X-ray phase analysis. The effect of nanoparticle concentration on the electrical conductivity of water-based nanofluids was studied. It was found that when nanoparticles are added to water, the electrical conductivity of nanofluids increases, however at concentrations above 0.01 wt%, the electrical conductivity begins to decrease.

Research of physical-mechanical and physical-chemical properties of foam concrete with complex polymer - mineral additive of a new generation based on local raw materials

The results of physical-mechanical and physical-chemical analysis using X-ray phase analysis of foam concrete and the processes of change in hydration, crystallization in cement systems, with the addition of complex chemical additives of the new generation of the Relaxol KDJ-3 series are presented. It has been established that in cement systems these additives help create new formations that crystallize in a finely dispersed form, clog the pores and capillaries of Portland cement stone, compacting and strengthening its structure.

ИССЛЕДОВАНИЕ ФАЗОВОГО СОСТАВА КОМПОЗИЦИОННЫХ ВЯЖУЩИХ ДЛЯ ГИДРОТЕХНИЧЕСКОГО БЕТОНА

The article studies production of composite binders for hydraulic concrete. Vitreous perlite from the Mukhor-Tala deposit of the Republic of Buryatia was used as an active mineral additive for the composite cement binder. Pozzolanic activity of vitreous and crystallized perlites was determined. Assessment of physical and mechanical properties and phase composition of autoclave-cured lime-perlite binders were carried out for subsequent assessment and identification of the hydrate phases of the composite cement binder. An X-ray phase analysis of Portland cement and a composite binder with vitreous perlite with a specific surface area of 600 m2/kg was carried out. The study established that use of active mineral additive based on glassy perlite leads to increase in amount of low-basic calcium hydrosilicates in cement stone. Electron microscopic analysis of composite binders for concrete hydraulic structures was carried out.

Влияние механической обработки исходных реагентов на структурные и электрические свойства LiFeO2 керамики

This work investigates the effect of mechanical treatment of initial Fe2O3 and Li2CO3 powders on the structure and electrical properties of lithium ferrite ceramics of the chemical composition LiFeO2. Mechanical treatment was carried out in an AGO-2S ball mill for 60 minutes at a bowl rotation speed of 2220 rpm. Sintering of ceramic samples was carried out in a laboratory furnace at 1050 °C for 1 hour. Using X-ray phase analysis data, it was shown that the introduction of the mechanical treatment of powders leads to a decrease in the concentration of the α-LiFeO2 phase in ferrite ceramics from 97,9 to 93,9 wt.%, as well as an increase in the secondary LiFe5O8 phase from 2,1 to 6,1 wt.%. In this case, during sintering, a more homogeneous and finely porous structure of the samples was formed. Based on the temperature dependences of the electrical conductivity of the samples, it was established that changes in electrical resistance are associated both with the microstructure and with the processes of adsorption-desorption (depending on temperature) of gas from the surrounding atmosphere into ferrite ceramics. The ferrite ceramics obtained by mechanical treatment is of interest for its further use as an adsorption material for carbon oxides.

Modeling of X-Ray Phase Contrast Imaging of Optically Heterogeneous Objects

Modeling of X-Ray Phase Contrast Imaging of Optically Heterogeneous Objects

Mechanical Activation as a Stage of Coal Sample Preparation in the Analysis of Rare Earth Elements Content by Inductively Coupled Plasma Mass Spectrometry

Background: Brown coals are recognized as promising sources of rare earth elements (REEs). Rare earths are present in both the mineral and organic parts of brown coal. Objectives: This study was conducted to investigate the influence of preliminary mechanical activation in the process of sample preparation prior to analyzing the concentrations of rare earth elements in brown coal samples of various origins and compositions Methods: Four coal samples from different deposits in Russia were selected for the study. Samples were treated with mechanical activation, without reagents, or mechanochemical activation, with humic acids added externally as reagents. X-ray phase analysis was carried out with the selected samples. The quantities of rare-earth elements present in the samples were studied by the method of high-sensitivity inductively coupled plasma mass spectrometry (ICP-MS). Results: It was found that the mechanical activation of coal before dissolution in a mixture of nitric and hydrofluoric acids leads to an increase in the determined concentration of rare earth elements. For this study, the expediency of using only nitric acid as an optimal solvent for the elemental analysis of coal samples was shown. The total concentration of all REE after dissolution of nitric acid and mechanochemical activation with humic acid reached 2456 g/t in Vanchin coal, 968 g/t in Azeysky coal, and 24 g/t and 150 g/t in Itatsky and Spetsugli coals, respectively. Conclusion: Mechanical activation and mechanochemical treatment can greatly help to facilitate sample preparation of natural objects, such as coals for elemental analysis, but in some cases, only a change of solvent is sufficient. When developing technology for concentrating rare earth elements from coal involving grinding, it is necessary to take into account the fact that mechanical activation of coal changes its tendency to dissolve, which may affect the results of the analysis and should be taken into account during experiments.

Synthesis, thermal stability and catalytic activity of Ce0.72Zr0.18Pr0.1O2-δ nanodispersed solid solution in CO oxidation reaction

A nanodispersed solid solution based on the Ce0,72Zr0,18Pr0,1O2-δ crystal lattice was synthesized by co-precipitation followed by heat treatment. The identification of the material was carried out by X-ray phase analysis, energy dispersive analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, low-temperature nitrogen adsorption, and gas chromatography. It has been established that the synthesized Ce0,72Zr0,18Pr0,1O2-δ solid solution is superior in catalytic activity and thermal stability to CeO2 and Ce0,8Zr0,2O2 due to doping with Pr+3 ions.

Термическое разложение бензоатов и аминобензоатов Mn (II), Co (II), Ni (II), Cu (II)

The article discusses the main methods for obtaining carbon composite nanomaterials and highlights the thermolysis method as one of them. To understand the essence of thermal decomposition processes as a synthesis method for carbon nanomaterials, thermolysis of aromatic carboxylates of such elements as manganese(II), cobalt(II), nickel(II), and copper(II) was considered. The article thoroughly discusses the synthesis procedure for these metal carboxylates under simple conditions. The thermal decomposition process was carried out in two environments (air as oxidizing one and argon as neutral one) to compare the products obtained. For a detailed study of the decomposition processes of manganese(II), cobalt(II), nickel(II), and copper(II) carboxylates, thermal analysis methods (TG and DSC) were used on a Netzsch 449 Jupiter synchronous thermal analyzer. To study the morphology and composition of the products, the methods of X-ray phase analysis, optical and scanning electron microscopy, and X-ray fluorescence microanalysis were used. The devices used were a Rigaku Ultima IV X-ray diffractometer and a scanning electron microscope with a Jeol JSM-7001F. The mechanisms of thermal decomposition of manganese(II), cobalt(II), nickel(II), and copper(II) carboxylates were suggested. For a more accurate determination of the composition of the synthesis products of manganese(II), cobalt(II), nickel(II), and copper(II) carboxylates and for a more accurate description of the processes of thermal decomposition of these salts, the corresponding aromatic carboxylic acids were also thermally decomposed. The appendix to the article presents thermograms of manganese(II), cobalt(II), nickel(II), and copper(II) aromatic carboxylates.

PLASMA DISCHARGE IN LIQUID MEDIA UNDER THE EFFECT OF ULTRASOUND FOR THE SYNTHESIS OF FILLERS FOR POLYMER COMPOSITES WITH ENHANCED MECHANICAL STRENGTH AND GAS PERMEABILITY

Zinc oxide nanoparticles were synthesized using a plasma discharge method under the effect of ultrasonic cavitation, and films of a polymer composite material were obtained and studied. Comparatively, the mixture of zinc oxide nanoparticles with planar graphene oxide nanostructures were also used as a filler. Using melt compounding technology, composite materials were obtained in the form of thin films consisting of the copolymer of ethylene and vinyl acetate and nanoparticles of zinc oxide and graphene oxide. The obtained samples of composite materials were examined by X-ray phase analysis, X-ray fluorescence analysis, and scanning electron microscopy. The physical, mechanical, and gas transport properties of composite films made of polymers filled with nanoparticles were studied: permeability measurements were carried out for carbon dioxide and helium gases.

Структура и прочность пористых материалов на основе порошков карбида титана разной дисперсности

Materials with porosity from 67.5 to 82.5 % were obtained from mixtures of titanium carbide powders and ammonium bicarbonate blowing agent by sintering in vacuum at temperatures of 1300 – 1500 °C. X-ray phase analysis of porous materials found that the crystal lattice parameter decreases with increasing sintering temperature. This indicates a decrease in the content of bound carbon C/Ti in titanium carbide. As a result of a comparative study of the obtained according to bending test strength characteristics of materials synthesized from nano- and submicron titanium carbide powders, it was found that the strength have close values. Ultimate bending strength are in the range of 2.6 – 18.1 MPa. As the porosity of the material increases, the tensile strength decreases. Fracture is brittle. In the fracture of materials obtained from titanium carbide nanopowder, destruction is observed both along the body and along the grain boundaries regardless of the sintering temperature. In materials obtained by sintering submicron titanium carbide powder at 1500 °C, the destruction occurs predominantly along the body of the grains. It has been found that under the same sintering conditions, the density of the porous material made of titanium carbide nanopowder is higher than that of the material made of submicron powder.

Study of Optical Properties and Structural Features of Object using the X-ray Phase Contrast Method

Study of Optical Properties and Structural Features of Object using the X-ray Phase Contrast Method