Diffractometry Methods Research Articles

Spectral methods of identification of structural transformations in particles of polymineral complexes

Abstract In recent years, new deposits of polymineral complexes have been actively discovered and are beginning to be developed in the Orenburg region of Russia. Knowledge of the structural features of such heterogeneous systems will help provide a controlled structural evolution. Such studies will help shorten the time needed for the introduction of raw materials into production processes of functional ceramics. A selection of physical and chemical methods has been chosen to analyze natural polymineral complexes in order to understand the temperature evolution of their phase composition and structural transformations. The polymineral complexes from deposits in the Orenburg region of Russia are known to be fusible. Infrared spectroscopy and diffractometry methods have been used to identify six to ten crystalline phases in the studied objects. The main phases have been identified as follows: quartz, calcite, kaolinite, montmorillonite, clinochlore, and magnetite. Structural changes were induced by heating the sample to 1200 K at a rate of 10 K/min while recording derivatograms. EPR spectroscopy established that impurity centers have an ambiguous role in the evolution of natural mineral structures. They can both stabilize crystal lattices and cause distortions due to the Jahn-Teller effect. This is particularly true for layered lattices that contain octahedral motifs with a central impurity ion. It has been demonstrated that impurity centers Fe3+ and Mn2+ act as spin labels for structural transformations. As a result of the destruction of crystal components, these impurity centers form clusters with each other and become undetectable by other methods of analysis.

The Use of a Laser Diffractometer to Analyze the Particle Size Distribution of Selected Organic Soils

This study was conducted to verify the usefulness of the laser diffractometer method for determining the particle size distribution of selected organic soils from the Podkarpacie region in Poland. The soil selected for this research represented three main classification groups, namely, low-organic, medium-organic and high-organic soil, in accordance with the standard criterion. Particle size distribution was determined using two types of laser diffractometers: the Helos laser diffractometer manufactured by Sympatec GmbH (Clausthal-Zellerfeld, Germany) and the laser particle size analyzer Analysette 22 MicroTech plus manufactured by Fritsch GmbH (Idar-Oberstein, Germany). The standard mechanical and sedimentation methods, which are perfect for testing mineral soils, are not applicable to organic soils; therefore, a serious problem was found and examined. A reference method that could verify the test results obtained using the laser diffractometer methods was required. After analyzing the literature, the hydrometric (sedimentation) method was adopted as the reference method. Currently, there are no reliable and fully verified methods for testing soils with such a complex skeleton structure, and the resources, standards and guidelines concerning the issues discussed are extremely limited; therefore, new research methods are being sought to fill this gap, and this work is a step in this direction. The results of the conducted studies and analyses have shown that laser diffractometry methods can be useful for determining the particle size distribution of organic soils, but to a limited extent, depending mainly on the quantity of organic substances. The highest agreement was obtained by comparing the results of the sedimentation method with those obtained using the diffractometer analyzer Analysette 22 in the group of highly organic soils.

In situ synchrotron X-ray diffraction study of synthesis reactions in mechanically activated Ti + Al powder mixture under linear heating conditions

In the present work, we studied the features of phase formation in mechanically activated Ti + Al powder mixture at various heating rates for the first time. The study was carried out using high-resolution diffractometry method which made it possible to study the processes of phase formation in situ at any stage of heating. It was established that ignition of the activated mixture can be initiated in the solid phase with an extremely low content of reaction products formed at the preheating stage. An increase in the heating rate leads to a decrease in the average burning rate and an increase in the ignition temperature. At high heating rates, the ignition is initiated in the presence of a liquid phase when the ignition temperatures are close to the melting temperature of aluminum. In this case, the content of reaction products formed during preheating stage is relatively high. It was found that the all main compounds presented in the equilibrium diagram of Ti-Al system are synthesized in parallel. The content of phases in the reaction products depends on the heating rate.

BOTTOM SEDIMENTS OF SURFACE WATERCOURSES OF THE MALMYZHSKY MOUNTAIN RANGE

X-ray fluorescence, electron microscopic, sedimentation analyses and laser diffractometry methods were used to study the composition of bottom sediments of surface watercourses of the Malmyzhskaya Ridge section allocated for the construction of a mining and processing plant (Khabarovsk region, Russia). It is established that the bottom sediments of the coastal zone of the watercourses of the studied area are characterized by a similar gross composition and physical and chemical properties (pH, solid phase density, total carbon content, wetting edge angle CAW). Th ey are mainly represented by fine earth with a high proportion of suspended sediments, in which the fraction of coarse silt prevails (particle size <2,0 mm, <0,1 mm and 0,01-0,05 mm, respectively). It is shown that deforestation in the sources of watercourses accompanied by soil erosion leads to a significant increase in the dispersion of sediments (an increase in the proportion of suspended sediments up to 90%) in the upstream. Downstream, with the distance from the felling sites, the infl uence of deforestation on the dispersion of deposits fades. Th e content of suspended sediment is reduced to values characteristic of watercourses in the catchment area of which deforestation has not been carried out. Significant microaggregation of suspended sediments of watercourses was revealed, the participation of microbiota (testate amoebas of xenosome taxa, diatoms and Fereducing bacteria) in the formation of microaggregates was diagnosed. Th e latter are involved in the formation of vivianite on the surface of ferruginous-clay microaggregates with an increased content of phosphates after fires. The mechanism of formation of toroidal microforms of vaterite in bottom sediments with the participation of cyanobacteria of the Spirulinaceae family is proposed.

SYNTHESIS AND INVESTIGATION OF STRUCTURAL, SURFACE MORPHOLOGICAL AND OPTICAL PROPERTIES OF InSe/PMItz HYBRID HETEROJUNCTION

On a series of annealed and unannealed InSe thin films which were formerly produced by electrochemical deposition method, organic PMItz semiconductor compound was growth by physical vapour deposition (PVD) method. Structural analyses of the films carried out by X-ray diffractometry (XRD) method revealed that glass/ITO/InSe film formed in hexagonal InSe phase while glass/ITO/InSe(annealed) film formed in monoclinic In6Se7 and orthorombic In4Se3 phases. Surface analyses of the layers forming heterojunction were conducted by atomic force microscoby (AFM) and it is observed that the layers are homogenous and have different roughness values. Optical analyses of the films demonstrated that annealing of the film result with increased absorption coefficient and reduced energy band gap. Moreover, other optical parameters of the films i.e. refractive indice(n), extinction coefficient (k), real dielectric constant(Er), imaginary dielectric constant(Ei) and optical conductivity were determined and compared within 300-1000 nm range.

WITHDRAWN: Toxicity Assessment of Montmorillonite Clay of Western Kazakhstan as a Natural Mineral Sorbent for Animals and Poultry

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Developing Self-Assembled Starch Nanoparticles in Starch Nanocomposite Films.

Starch nanoparticles (SNPs) are synthesized by different precipitation techniques using corn starch, and SNP films are prepared by the evaporation casting method. The morphological study is investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The distribution and sizes of precipitated SNPs after synthesizing are discovered by these methods as well. The crystallinity of the SNPs is studied by the X-ray diffractometry (XRD) method that demonstrates reduction compared to neat starch granules, and it is changed from A-style to VH-style after precipitation. The chemical bonding of different SNPs after the nanoprecipitation is analyzed by Fourier transform infrared spectroscopy (FT-IR). Thermogravimetric analysis (TGA) demonstrates the decomposition of starch nanoparticles and the starch matrix that is related to the depolymerization of carbon chains in the range of 260 to 350 °C. The mechanical properties of the SNP films versus the temperature changing are discovered by dynamic mechanical analysis (DMA). The water contact angles of SNP films are measured using a goniometer, and the results showed the hydrophobic surfaces of the prepared films. Our study indicates that SNPs have a promising impact on the properties of corn starch films, which would be useful in biodegradable packaging material.

Chemiresistive CuO sensors for label-free C-reactive protein detection

In this study, we developed fast and highly sensitive, label-free Ca-doped cupric oxide (CuO) based chemiresistive biosensors to detect C-reactive protein (CRP). The Successive Ionic Layer Adsorption and Reaction (SILAR) method was used to deposit pure and Ca-doped CuO thin films on interdigitated gold electrodes. Film surfaces were functionalized with monoclonal anti-C-reactive protein antibody (anti-CRP) by random physisorption method. Sensor fabrication steps were monitored using the linear sweep voltammetry method. Scanning electron microscopy was used to investigate the surface morphology. Energy-dispersive X-ray spectroscopy was used to determine the elemental composition. The structure of the films was investigated by the powder X-ray diffractometry method. Sensor parameters were determined by the change in sensor resistance over time. The sensors showed a good response to CRP with a linear detection range of 0.1–5.0 µg/ml, which was within the clinically significant range. Detection limits of 49.61 and 48.81 ng/ml were estimated using the standard deviation of the y-intercept and the standard deviation of the regression line, respectively. Dynamic response times of all fabricated sensors were found to be less than 30 s

On the diffraction peak amplitude measured by neutron reverse time-of-flight (RTOF) diffractometry

For the first time, a detailed analysis of the diffraction peak amplitude dependence on the maximum neutron beam modulation frequency, measured by the reverse time-of-flight (RTOF) diffractometry method, has been carried out. It is shown that this dependence can be explained by a combination of the “collimation” effect due to neutron beam modulation by a Fourier chopper and the presence of a nonzero geometric component ΔdG of the peak width. A set of experimental data obtained on the Fourier diffractometers FSD, FSS, and HRFD confirmed this hypothesis and is in good agreement with the proposed model. An approach is proposed to optimize the relationship between intensity and resolution of a Fourier diffractometer.

Influence of dislocation structure on electrical and spectroscopic properties of MoOx/p-CdTe/MoOx heterostructures

The defective structure of p-CdTe:Cl single crystals and MoOx/p-CdTe/MoOx heterostructures were investigated by high-resolution X-wave diffractometry methods. Different models of dislocation systems were used and the dislocation densities were estimated from the Williamson-Hall plot. It is noted that significant deformations of the mismatch in the transition layer negatively affect the current–voltage characteristics of heterostructures.

Thermal expansion, crystal structure, XPS and NEXAFS spectra of Fe-doped bismuth tantalate pyrochlore

The thermal behavior, crystal structure and charge state of ions in the composition of a new pyrochlore Bi1.6Fe0.8Ta1.6O7.6 (refined formula Bi1.50Fe0.60Ta1.40O6.77) synthesized via standard ceramic method are studied. The disordered pyrochlore structural parameters were obtained by the Rietveld method (sp. gr. Fd-3m:2 (227), 10.49689(3) Å, Z = 8). Iron (III) ions occupy octahedral positions of tantalum (V). The sample is characterized by a loose microstructure formed by partially fused grains with a longitudinal size of 0.2–2 μm. Using the high-temperature x-ray diffractometry method it was found that Fe-doped bismuth tantalate pyrochlore is thermally stable up to a temperature of ∼1140 °C. The unit cell parameter a and coefficient of thermal expansion (TEC) uniformly weakly increase from 10.4796 Å to 10.5603 Å and from 4.5 × 10−6 °C−1 to 9.2 × 10−6 °C−1, respectively, in the temperature range of 30 ÷ 1050 °C. This behavior is typical for frame structures of the pyrochlore type. The pyrochlore thermal behavior in the low-temperature region (−170 ÷ 100 °C) is characterized by high growth of TEC from 1.3 × 10−6 °C−1 (−170 °C) to 4.6 × 10−6 °C−1 (100 °C) with respect to a weak increase in a from 10.48627 (−70 °C) to 10.49444 Å(100 °C). According to the data of near edge X-ray absorption fine structure and X-ray photoelectron spectroscopy, the ion charge states were determined as Bi (III), Ta(V), Fe(III).

Characterization of novel lunar highland and mare simulants for ISRU research applications

Lunar regolith is the most critical material for the in-situ resource utilization in the crewed Moon exploration missions. This natural material can be utilized for the additive manufacturing of concrete or ceramic parts on the Moon's surface to support permanent human presence on the surface of Earth's natural satellite. Due to the scarcity of regolith on Earth, its simulants are used in lab research to prepare the technology for Moon missions. The present study is devoted to the characterization of lunar regolith simulant material, recently developed by the University of Central Florida, that is considered as a suitable material for regolith-focused additive manufacturing technologies. This paper describes the characterization of the LHS-1 and LMS-1 simulants using XRF, XRD, SEM, EDX, DTA, TGA, UV/Vis/NIR spectroscopy, and Laser diffractometry methods to provide data on their mineral, chemical, and fractional composition, as well as, on their morphology and optical properties. The results were compared to the data of the previously developed simulants and the original lunar samples delivered by Apollo and Luna missions. It was found that LHS-1 and LMS-1 simulants well mimic the primary properties of the original lunar regolith and can be potentially used for ISRU research tasks.

ПРИМЕНЕНИЕ РЕНТГЕНОВСКОЙ ДИФРАКТОМЕТРИИ ПРИ ПОСТРОЕНИИ ДИАГРАММ СТРУКТУРНЫХ СОСТОЯНИЙ ДЕФОРМИРУЕМЫХ СПЛАВОВ АВИАЦИОННОГО НАЗНАЧЕНИЯ

Axisymmetric hot compression experiments of nickel superalloy ЭП975-ИД, ЭП742-ИД and MA2, MA3 alloy specimens in a wide temperature and rate intervals were carried out. Structure formation was studied by х-ray diffractometry methods. Structure diagrams plotting method is based on using of the test machine which has been adjusted on compression, and structure studying is developed. Diagrams can be used for development and optimization of hot pressure technology parameters, for the purpose receiving preparations with the regulated structure.

Surface coating preparation of spherical magnetic materials

Magnetic materials are being increasingly used in anti-counterfeiting coatings, but the dark colors of magnetic materials greatly limit their applications. This necessitates the development of light-colored magnetic materials. In this study, the heterogeneous precipitation method was used to deposit a layer of titanium dioxide (TiO2) on the surface of magnetic spherical metal particles, followed by the deposition of a layer of Ag by the reduction method, in order to achieve a light color. In the experiment, the particles were initially coated with a few tens of nanometers of TiO2 with a strong shading effect, followed by a further coating of Ag of the same thickness with a similar shading performance. Not only did this achieve a lighter color, but there was no reduction in the magnetic properties of the material after the application of the coating. Scanning electron microscopy (SEM), scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS), X-ray diffractometry (XRD), and other methods were used to study the changes in morphology and composition before and after the magnetic material was coated. A magnetic tester was used to study the changes in magnetic strength before and after the magnetic material was coated.

Material based on multilayer periodic structures with GeSiSn pseudomorphic layers

The growth of multilayer structures with Ge0.3Si0.7-yGey/Si heterojunction at tin content from 0 to 18% was studied. The X-ray diffractometry method shows the presence of strict periodicity of layers and a high level of tin content. It has been established that GeSiSn compounds are thermally stable in the annealing temperature range of 300-550 °C. A photoluminescence signal in the infrared range of about 3 microns is observed from a structure with pseudomorphic GeSiSn layers.

Study of Residual Welding Stresses for Underwater Wet Welding of Low-Alloy Steel Using Magnetic Anisotropic and X-ray Diffractometry Methods

Study of Residual Welding Stresses for Underwater Wet Welding of Low-Alloy Steel Using Magnetic Anisotropic and X-ray Diffractometry Methods

The Latowu Ultramafic Rock-Hosted Iron Mineralization in the Southeastern Arm Sulawesi, Indonesia: Characteristics, Origin, and Implication for Beneficiation

Latowu ultramafic block in the Southeastern Arm Sulawesi locally hosts elevated concentrations of Fe in addition to Ni. We investigated both host rock and mineralized samples' mineralogy and chemistry to find out mineralogical and chemical characteristics and interpret the iron mineralization process with beneficiation implications. The mineralogical nature of the samples was analyzed using optical microscopy and X-ray diffractometry (XRD) methods. The whole-rock and mineral chemistry analyses were performed using X-ray fluorescence (XRF) spectroscopy and electron probe microanalysis (EPMA) techniques. The analysis showed that the ultramafic rocks had been undergone a strong to complete serpentinization degree where lizardite appears to be the predominant mineral. Magnetite in this research comprised the principal iron-bearing mineral and functioned as discrete fine-grains and subhedral to anhedral crystals. Magnetite occurs as fragments in breccia, alteration rim in spinel, fine-grained disseminations, and micro veins. This research found that the whole-rock chemistry of an ultramafic breccia showed an elevated concentration in Fe2O3 with a grade of 28.44 wt%. Electron probe analysis of magnetite shows a wide variation of Fe ranging from 31.10 wt% to 67.20 wt%. It is interpreted that the formation of magnetite within ultramafic rocks is influenced by the hydration of primary minerals, mainly olivine. Iron is most likely released from olivine or pyroxene crystals during serpentinization, and the higher water content of serpentine promotes its mobility. It is suggested that the magnetic separation method can be potentially used to increase the Fe grade.

The effects of cold rolling and aging conditions on the microstructure and magnetic properties of a semi-hard Fe–Mo–Ni magnetic alloy

Experiments were conducted to examine the effect of prior cold rolling and ageing conditions on the microstructure and magnetic properties of a ternary Fe–Mo–Ni magnetic alloy. For this purpose, a semi-hard Fe–18Mo–5Ni (wt. %) magnetic alloy was cold rolled at various reductions in area of 65, 80, and 95% for inducing the magnetic anisotropy. The cold rolled specimens were then aged at the various temperatures of 570, 610, and 640 °C for the different times of 1, 2, 3, and 6 h. The cold-rolled and aged specimens showed the crystallography texture as characterized by X-ray diffractometry method. The crystallography texture was described as the parallel orientation of the {002} family planes with the surface of rolling. The preferred orientation of {002} planes was intensified by cold-rolling, while it weakened by subsequent aging treatment. The coercive force was controlled in the range of 23–110 Oe by adjusting the ageing temperature and time due to the formation of the ferromagnetic (Fe,Ni)7Mo6 precipitates as revealed by optical and electron microscopy techniques. Furthermore, the magnetic measurements by vibrating sample magnetometer showed that the remanence and squareness increased from 0.94 to 1.2 T and from 0.58 to 0.77, respectively.

Stability of Aggregates Made by Earthworms in Soils with Organic Additives

Earthworm activity is a key factor in creating soil aggregates, but introduced organic matter and abiotic factors are also equally important. The purpose of this study was to investigate the stability of aggregates made by earthworms in soils with organic additives. Additionally, the two aggregate stability measurement methods were compared: (i) the wet-sieve method and (ii) the laser diffraction method. A six-month container experiment containing sixteen treatments and controls were made. Each treatment included one of four types of soil texture: sand, loam, silty loam and clay, and one of four additives: straw, peat, compost and compost with added microorganisms. To each treatment, six earthworms were added, two each of species commonly occurring in Polish soils: Dendrodrilus rubidus, Aporrectodea caliginosa and A. rosea. This study confirmed that earthworm activity was the factor favoring aggregate formation. In terms of the investigated organic additives, the efficiency of aggregate creation was as follows: compost with active bacteria, compost, peat and straw. Nevertheless, earthworms alone, without the addition of an organic additive, did not form permanent aggregates. The wet sieving and laser diffractometry methods of measuring aggregate stability were comparable for silty, clayey and loamy soils.

Использование метода самовозгорания для получения замещённого алюминием гексаферрита бария

Oxide materials have traditionally attracted the attention of researchers around the world. This is due to their wide range of applications: electrical engineering, electronics, special coatings, chemical technologies, etc. Doping of oxide materials with various elements such as Al, Bi, Zn, Co, Sn, Ti, B, Sb and others is widespread in order to fine-tune their physicochemical properties. In particular, doping of barium hexaferrite with aluminum is of particular interest, since this allows one to change such important parameters as saturation magnetization (σS), coercive force (HC), squareness coefficient of the hysteresis loop (K), as well as to influence the anisotropy field and microwave properties of the material. Since the preparation of BaAlxFe12-xO19 by the classical ceramic method requires thorough grinding of the starting materials, preliminary sintering, high temperature (above 1300 °C) and duration of the synthesis, it was decided to test an alternative method for obtaining aluminum-substituted barium hexaferrite. As such, we have chosen the self-combustion method. During the synthesis a solution of nitrates of the corresponding metals with citric acid was prepared. After neutralization and evaporation of the solution, the resulting mass was heated in a muffle furnace to carry out the spontaneous combustion process and remove residual carbon. The final sintering of samples with the composition BaAlxFe12-xO19 (for x = 0, 1, 2, and 3) was carried out in a muffle furnace with a precision temperature controller at 1100 °C for 4 hours. The obtained samples were studied by the powder diffractometry method, scanning electron microscopy, and X-ray spectral microanalysis. It has been established that the self-ignition method makes it possible to obtain homogeneous samples of barium hexaferrite substituted with aluminum at a lower temperature compared to the classical ceramic method. The parameters of the structure of the obtained samples were also determined. The tested method not only makes it possible to obtain aluminum-substituted barium hexaferrite at lower temperatures, but also makes it possible to dope ferrites with highly volatile elements.