Thermal X-ray Research Articles

Optimizing microwave-assisted synthesis of akermanite nanoparticles using citric acid as a chelating agent: A combined machine learning and experimental approach

This study aims to synthesize akermanite (Ca2MgSi2O7) using an eco-friendly and fast microwave-assisted method and understand the effect of using citric acid (CA) as a chelating agent to optimize the calcination temperature for synthesizing pure akermanite nanoparticles (along with a trace amount of merwinite) at low calcination temperatures. This study developed a new predictive model by machine learning-assisted modeling to advance the understanding of relationship between synthesis parameters and the resulting purity and particle size of akermanite. To evaluate the reliability of the developed model in predicting the purity and characteristics of the resultant Ak powder, the crystallization behavior and phase formation sequence of citric acid-containing samples and those without citric acid were experimentally investigated by differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. Following validation and training, the developed model indicates promising effects of citric acid on reducing crystallization temperature, enhancing purity, and decreasing particle size. The synthesized powders were further characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM) analyses. For the first time, our results addressed the microwave-assisted synthesis as an effective method via experimental evidence and machine learning-assisted modeling that allows for the production of akermanite containing a trace amount of merwinite with the aid of citric acid at a relatively low calcination temperature of 950 °C. In vitro bioactivity evaluation supported the potential suitability of Ak powders for bone tissue engineering applications.

Experimental and molecular simulation analysis of the dissolution behavior of Musk ambrette in organic solvents

The solubility of Musk ambrette in i-propanol (IPA), i-butanol (IBA), n-heptane (HPT), n-hexane (HX), cyclohexane (CYH), methyl acetate (MAC), ethyl acetate (EAC), acetone (ACE), IPA + ACE at 278.15 K to 318.15 K was determined. The mole fraction solubility of Musk ambrette in pure IPA at the temperature of 298.15 K were found to be 0.9492 × 10-2 mol·mol−1. The difference is that the solubility of Musk ambrette in ACE reaches 0.2257 mol·mol−1, which is much higher than the solvent mentioned above. The strong intermolecular hydrogen bonding formed by IPA resulted in its lowest solvation capacity for Musk ambrette. In addition, to further investigate the solubility pattern of Musk ambrette, we used 8 models (Van’t Hoff, modified Apelblat, Buchowski-Ksiazczak, Yaws, NRTL, Wilson, Jouyban-Acree and Sun model) to fit and obtain a general equation for solubility versus temperature. These results yielded a large amount of statistically significant data. Comparisons revealed that the modified Apelblat and Yaws equation showed the least deviation in forecasting solubility variations with temperature. Meanwhile, we proved that the dissolution of Musk ambrette is a heat-absorbing entropy increasing process by Van't Hoff equation calculation. ΔsolGo for the 12 solvents is in the following order: ACE < MAC < EAC < w = 0.2007 < w = 0.4025 < w = 0.6076 < CYH < w = 0.8070 < HPT < HX < IBA < IPA. ΔsolGo is smaller the easier it dissolves, which is consistent with the law of dissolution. Secondly, we performed thermal analysis and X-ray diffraction tests on Musk ambrette crystals prepared in different solvents, which showed that none of the several systems investigated led to the creation of new crystalline forms or solvatoids, further confirming the suitability of the solvents. Besides, we discuss the correspondence between solubility and the HSP, π, α, β, and CED of the solvents and thus tentatively confirm the significant influence of the solvent properties on solubility. The principle of similarity and compatibility is satisfied for most of the solvents. In particular, the CED values of the larger solvents were not favorable for the solubilization of Musk ambrette. We also analyzed the molecular surface electrostatic potential of Musk ambrette by visualization techniques. Finally, IPA and ACE and their binary solution systems were analyzed by molecular dynamics simulations. The effect of solvent intermolecular interactions on the solubilization pattern was discussed. It was further confirmed that weak interactions of solvent molecules contribute more to the dissolution of Musk ambrette. These findings suggest that the prediction of solvent solubility can be initially achieved by molecular simulation techniques. Undoubtedly, this study will furnish a valuable information for the purification of Musk ambrette.

Heterophase synthesis of rare-earth zirconates

This study focuses on developing a heterophase process for synthesizing rare-earth zirconates, specifically R2Zr2O7 /R2O3·2ZrO2 (R = La, Sm, Gd, Dy). We investigated the sorption properties of low-hydrated zirconium hydroxide, a precursor for complex-oxide phases, towards rare-earth elements' ions (La, Sm, Gd, Dy). The results indicate that sorption by low-hydrated zirconium hydroxide is a multifaceted process, involving the incorporation of rare-earth cations into the pores of low-hydrated hydroxide and ion exchange. The paper details the synthesis of R2Zr2O7 /R2O3·2ZrO2 (R = La, Sm, Gd, Dy), considering both «light» and «heavy» elements. The process process involves the interaction between Zr(OH)3÷1O0.5÷1.5·(1.6÷2.6)H2O, low-hydrated zirconium hydroxide, and an aqueous solution of rare-earth acetate (С(La3+) = 0.155 mol/l, С(Sm3+) = 0.136 mol/l, С(Gd3+) = 0.141 mol/l, С(Dy3+) = 0.120 mol/l) followed by heat treatment. The resulting phases and their thermolysis products were analyzed using differential thermal analysis and X-ray phase analysis. Single-phase rare-earth zirconates R2Zr2O7 (R = La, Sm, Gd) and the Dy2O3·2ZrO2 solid solution were only obtained at 800 °С. The lattice parameters are calculated for each phase. Lanthanum, samarium, and gadolinium zirconates exibited a cubic pyrochlore structure (Fd3–m), while dysprosium displayed a fluorite structure (Fm3–m). The average particle size of all zirconates was 1.14 ± 0.02 μm.

An Evaluation of the Beneficial Effects of Polyamide 6's Thermal Stabilization by Ferric Chloride Complexation as a Novel Carbon Fiber Precursor

This study investigated the impact of stabilization time on pretreated polyamide 6 (PA6) fibers using various analytical techniques, including thermal analysis (TGA and DSC), infrared (IR) spectroscopy, X-ray diffraction (XRD), tensile testing, and density measurements. The two-step atmospheric air-based stabilization process for pretreated PA6 multifilament bundles involved initial thermal stabilization at 170 °C in an air atmosphere after ferric chloride impregnation, followed by a second step of thermal stabilization at 245 °C. Ferric chloride impregnation followed by thermal stabilization in an air atmosphere resulted in crucial structural transformations. The density values of the samples increased following thermal stabilization, accompanied by a decrease in tensile values. Ferric chloride pretreated and thermally stabilized PA6 fibers were found to be fully stabilized after 120 min of stabilization before the carbonization stage. The findings obtained from the DSC, XRD, and IR spectroscopy methods indicated the occurrence of disordering phases due to the scission of hydrogen bonds. The TGA findings showed significant increases in carbon yield percentages at 500 °C and 850 °C, reaching 71.4% and 63.5%, respectively, for the sample heat treated at 245 °C for 120 min. The addition of ferric chloride is expected to potentially reduce processing costs for final carbon fiber production by decreasing the time required for the thermal stabilization of PA6.

Fabrication of metal oxides-based adsorbents for SO2 capture with equimolar adsorption

A series of novel porous metal oxides (MO, M = Mg, Ca, Ba, Mn and Zn) adsorbents were synthesized through simple thermal treatment of the corresponding metal sulfite for the remotion of sulfur dioxide (SO2). The obtained MO adsorbents were characterized by various techniques including scanning electron microscopy (SEM), thermal gravimetric analyzer (TGA), X-ray diffraction (XRD) and nitrogen adsorption studies. The results show that the SO2 adsorption capacity of manganese oxide (MnO) is much higher than that of other MO. And due to its highly dispersed and large specific surface area, especially its well-developed pore structure, equimolar adsorption of SO2 can be achieved for the first time among similar SO2 adsorbents. In addition, different sources of MnO were explored and it was found that the MnO obtained from the decomposition of MnSO3 had the highest SO2 adsorption capacity. Adsorption kinetic studies show that the reaction between MnO and SO2 conforms to the pseudo-second-order kinetic equation. Furthermore, it was found through seven-cycle experiments that the adsorption amount tended to stabilize in each of the following cycles, except for the first high temperature, which led to changes in the adsorbent and a decrease in cycling performance. This strategy has three advantages: one-step preparation at low temperatures, equimolar adsorption of SO2 as well as good reusability and selectivity.

PHASE RELATIONS IN THE Bi2-Bi2Se3-Bi2Te3 SYSTEM AND CHARACTERIZATION OF SOLID SOLUTIONS

Phase relations in the Bi2–Bi2Se3–Bi2Te3 system were determined experimentally using differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Based on the experimental results, a solid-phase equilibria diagram at room temperature, a projection of the liquidus surface, and several polythermal sections of the phase diagram were constructed. The regions of primary crystallization and phase homogeneity, types, and coordinates of non- and monovariant equilibria were determined. Continuous solid solutions along the Bi8Se9–Bi8Te9, BiSe–BiTe, and Bi4Se3–Bi4Te3 sections, as well as wide areas of solid solutions based on other bismuth selenides and tellurides, were found. The established phase diagrams can be used for the synthesis of solid solutions of a given composition and the growth of their single crystals by directional crystallization from solution-melts

Fluorescent Fe K line emission of γ Cas stars

Context. γ Cas stars are early-type Be stars that exhibit an unusually hard and bright thermal X-ray emission. One of the proposed scenarios to explain these properties postulates the existence of a neutron star companion in the propeller stage, during which the magnetosphere of a rapidly rotating neutron star repels infalling material. Aims. To test this model, we examined the fluorescent Fe Kα emission line at ~6.4keV in the X-ray spectra of γ Cas stars, which offers a powerful diagnostic of both the primary source of hard X-rays and the reprocessing material. Methods. We computed synthetic line profiles of the fluorescent Fe Kα emission line in the framework of the propelling neutron star scenario. Two reservoirs of material contribute to the fluorescence in this case: the Be circumstellar decretion disk and a shell of cool material that surrounds the shell of X-ray-emitting plasma around the putative propelling neutron star. Results. We analysed the synthetic line profiles and expected equivalent widths of the lines for three well-studied γ Cas stars. The predicted line strengths fall short of the observed values by at least an order of magnitude. Pushing the model parameters to reproduce the observed line strengths led to column densities towards the primary X-ray source that exceed the observationally determined values by typically a factor of 20, and would further imply a higher X-ray luminosity than observed. Conclusions. The strengths of the observed Fe Kα fluorescent emission lines in γ Cas stars are inconsistent with the expected properties of a propeller scenario as proposed in the literature.

Refinement of the phase diagram of the MnSe– Ga&lt;sub&gt;2&lt;/sub&gt;Se&lt;sub&gt;3&lt;/sub&gt; system

Phase equilibria in the MnSe–Ga2Se3 system were re-investigated by differential thermal analysis (DTA) and X-ray diffraction (XRD) methods and its phase diagram was constructed, which somewhat differs from that presented earlier in the literature. It was established that the system is characterized by the formation of an intermediate phase (ã) with a wide (47–61 mol % Ga2Se3) homogeneity region. Based on Ga2Se3, a wide (~30 mol %) areas of solid solutions was also found. It is shown that the ã-phase undergoes a polymorphic transformation ã′↔ã at 1183 – 1193 K for various compositions. The high-temperature ã′-phase has a minimum melting at 1205 K and 55 mol% Ga2Se3 and is in peritectic equilibria with solid solutions based on both initial binary compounds. Based on powder diffraction data, the tetragonal lattice parameters of the ã-phase with compositions of 50 and 60 mol % Ga2Se3 were determined. The previously indicated ternary compound of the Mn2Ga2Se5 composition was not been confirmed. A comparative analysis of the obtained results with literature data was carried out.

Synergistic effects of microencapsulated bacterial spores and superabsorbent polymer on self-healing performance in mortar

This study explores the feasibility of utilizing a superabsorbent polymer (SAP) to improve the self-healing performance of microbial-induced calcium carbonate precipitation (MICP) in cement-based materials. The amount of microencapsulated bacterial spores was varied from 0.25–1 % by cement weight. The SAP content was set to either 0 or 4 % by cement weight. As additives, the impact of SAP and MICP bacteria on mortar properties, including flowability and compressive strength, was assessed. The self-healing performance was evaluated based on crack-healing percentage and water permeability recovery. Microstructural analyses, including thermogravimetry/differential thermal analysis (TG/DTA), X-ray diffraction (XRD), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), were performed to investigate the microstructural and chemical changes during the healing process. The findings revealed that specimens exclusively mixed with 4 % SAP exhibited a slightly lower crack-closure efficiency compared to those mixed exclusively with 1 % MICP bacteria. However, the SAP-containing specimens exhibited a higher degree of permeability recovery. Meanwhile, in the binary additive system with 0.5 % MICP bacteria and 4 % SAP, the specimens exhibited the highest crack-closure percentage of 91 % and a final water discharge rate of 15 mL/min after 45 days of healing. In contrast, specimens mixed exclusively with 1 % MICP bacteria showed a crack-closure percentage of 76 % and a final water discharge rate of 59 mL/min. These results suggest that incorporating SAP into the MICP system enables a reduction in MICP bacterial content without compromising self-healing performance.

Tailoring photocatalytic performance through Fe-doped TiO2/ZnO for effective remediation of organic contaminants

The development of highly efficient photocatalysts holds significant promise for addressing contemporary environmental challenges. This study focuses on the synthesis and characterization of a novel photocatalyst, iron-doped TiO2/ZnO particles, created through the sol-gel technique. The incorporation of iron ions into the crystalline structure of TiO2/ZnO aims to enhance the photocatalytic efficiency of TiO2. The findings revealed that Fe–ZnO/TiO2 exhibits a more thermally stable lattice compared to TiO2/ZnO, thereby retarding the phase transformation from anatase to rutile under higher calcination temperature. The photocatalytic performance of the synthesized photocatalyst was evaluated through the degradation of methyl orange under visible light irradiation. A statistical response surface methodology based on a central composite design was employed to develop a predictive model for color removal (as the dependent variable) considering variations in irradiation intensity, initial color concentration, catalyst concentration, reaction time, and pH (as independent variables). The analysis of variance identified the initial color concentration as the most influential factor, negatively affecting the predicted response. The experimental values of color removal exhibited good agreement with the predicted values from the regression model with a coefficient of determination of 0.949, indicating the accuracy of this model in predicting the mentioned outcomes. The presented model indicated that, for a sample of methyl orange with an initial concentration of 21.97 ppm, a reaction time of 117.69 min under direct irradiation of 21.63 W, a catalyst concentration of 0.61 g/L, and a pH of 4.74, the optimal color removal efficiency of 78.99 % was achieved.

GREEN SYNTHESIS OF FexOy STRUCTURES USING Euterpe oleracea MART EXTRACT FROM THE LEGAL AMAZON, BRAZIL

The synthesis of oxides using plant extracts as precursors has attracted attention as it is an economical, efficient, and ecological route. Euterpe oleracea Mart, available in the Legal Amazon, has great potential due to its composition, rich secondary metabolites. Therefore, this work aimed to investigate the potential of aqueous açaí leaf extract as precursors in synthesizing FexOy-type oxides. The synthesis was developed in two stages to obtain the hematite phases (step 1) and the magnetite phase (step 2). The effect of pH on phase formation and structure was evaluated in step 1. Then, the material was obtained in step 2 by precipitation with pH adjustment. The powders were characterized by thermal analysis, X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. The results showed that pH played a significant role in the thermal behavior, crystallite sizes, and structural parameters of hematite, with neutral or acidic pH being more attractive for obtaining crystallites between 21 and 24 nm. Magnetite with 21.51 nm crystallites was precipitated, indicating possible capping of the Fe3O4 particles and preserving their magnetic characteristics.

Artificial intelligence technologies utilization for detecting explosive materials

Explosive material detection considers the identification and classification of explosive materials using techniques from traditional sniffer dogs to cutting-edge sensing technology like thermal imaging, X-ray scanners, and chemical sensors. Explosive detection is applied in various locations, including airports, government buildings, and public areas, to prevent terrorist attacks and criminal actions that attempt to employ explosive devices. The effectiveness of these procedures is dependent on the detection materials, equipment, and environment, so new techniques are continuously explored to increase precision, sensitivity, and detection speed. Because explosive substances present a critical risk to infrastructure, security, and public safety, extensive analysis of existing detection methods is needed. This paper highlights key areas for further research and development in explosive materials detection by addressing identified limitations and challenges. Specifically, advancements in technology, interdisciplinary collaboration, and the integration of AI techniques offer significant opportunities for improving detection accuracy, reducing false positives, and ensuring safer environments for individuals and society.

Lithium germanosilicate glass formation, kinetics, stability and crystallization

Lithium disilicate glass (Li2O•2SiO2) was modified using GeO2 resulting in compositions Li2O•2GeO2•2SiO2 (L1G2S2), Li2O•GeO2•SiO2 (L1G1S1), and GeO2•SiO2 (L0G1S1). The glass formation was investigated and confirmed for compositions L1G2S2 and L1G1S1 through differential thermal analysis and X-ray diffraction. Two heat treatments were conducted in order to form a glass-ceramic and a sample with a larger crystalline fraction. The crystalline phase was identified through X-ray diffraction as a Li2(Ge,Si)2O5 solid solution of lithium silicate (PDF 010-70-4856). Raman spectra of all samples were analyzed and discussed. The presence of bands associated with Ge in defect sites in silica glass, and those associated with Si–O-Ge bonds suggest the network is established by both SiO2 and GeO2 and not two separate networks, which is consistent with the formation of a solid solution. The refractive index was measured for the glasses and glass-ceramics samples, revealing a very small dispersion between 0.3 and 0.8 μm.

3D evolution of a solar flare thermal X-ray loop-top source

Context. The recent launch of Solar Orbiter has placed a solar X-ray imager (Spectrometer/Telescope for Imaging X-rays; STIX) beyond Earth orbit for the first time. This introduces the possibility of deriving the 3D locations and volumes of solar X-ray sources by combining STIX observations with those of Earth-orbiting instruments such as the Hinode X-ray Telescope (XRT). These measurements promise to improve our understanding of the evolution and energetics of solar flares. However, substantial design differences between STIX and XRT present important challenges that must first be overcome. Aims. We aim to: 1) explore the validity of combining STIX and XRT for 3D analysis given their different designs, 2) understand uncertainties associated with 3D reconstruction and their impact on the derived volume and thermodynamic properties, 3) determine the validity of the scaling law that is traditionally used to estimate source volumes from single-viewpoint observations, 4) chart the temporal evolution of the location, volume, and thermodynamic properties of a thermal X-ray loop-top source of a flare based on a 3D reconstruction for the first time. Methods. The SOL2021-05-07T18:43 M3.9-class flare is analysed using co-temporal observations from STIX and XRT, which, at the time, were separated by an angle of 95.4° relative to the flare site. The 3D reconstruction is performed via elliptical tie-pointing and the visualisation by JHelioviewer, which is enabled by new features developed for this project. Uncertainties associated with the 3D reconstruction are derived from an examination of projection effects given the observer separation angle and the source orientation and elongation. Results. Firstly, we show that it is valid to combine STIX 6–10 keV and XRT Be-thick observations for 3D analysis for the flare examined in this study. However, the validity of doing so in other cases may depend on the nature of the observed source. Therefore, careful consideration should be given on a case-by-case basis. Secondly, the optimal observer separation angle for 3D reconstruction is 90° ± 5°, but the uncertainties are still relatively small in the range 90° ± 20°. Other angles are viable, but are associated with higher uncertainties, which can be quantified. Thirdly, the traditional area-to-volume scaling law may overestimate the 3D-derived volume of the thermal X-ray loop-top source studied here by over a factor of 2. This is beyond the uncertainty of the 3D reconstruction. The X-ray source was not very asymmetric, and so the overestimation may be greater for more elongated sources. In addition, the degree of overestimation can vary with time and viewing angle, demonstrating that the true source geometry can evolve differently in different dimensions. 3D reconstruction is therefore necessary to derive more reliable volumes. Simply applying a modified scaling law to single-viewpoint observations is not sufficient. Finally, the vertical motion of the X-ray source is consistent with previous observations of limb flares. This indicates that 3D reconstruction by elliptical tie-pointing provides reliable 3D locations. The uncertainties of thermodynamic properties derived from volume, temperature, and/or emission measure are dominated by those of the volume. In contrast to single-viewpoint studies, observationally constrained volume uncertainties can be assigned via 3D reconstruction, which lends quantifiable credibility to scientific conclusions drawn from the derived thermodynamic properties.

Effect of the strength grade of parent concrete on the performance of recycled aggregate treated by cement-fly ash slurry under prolonged soaking duration

The detrimental effects of quarrying natural resources have contributed to large-scale environmental pollution. Utilizing recycled concrete aggregate (RCA) obtained from construction and demolition waste as a replacement for natural aggregates has become an effective solution for environmental sustainability. However, the inevitably diminished characteristics of the adhered mortar and the existence of an additional interfacial transition zone (ITZ) have negatively suppressed the widespread use of these materials in production lines. The present study aims to comprehensively investigate the effects of a cement-fly ash slurry with a mass ratio of 50% of the total weight of RCA on the microstructure and engineering properties of RCA derived from three different parent concretes with strength grades of 20, 30, and 60 MPa. The RCAs were soaked for 24 h, 48 h, and 72 h to evaluate the long-term effects of the pozzolanic slurry. A sequence of laboratory tests was conducted, including mercury intrusion porosimetry (MIP) test, thermal gravimetric–differential thermal analysis (TG-DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses, and measurements of water absorption and crushing value. The MIP results demonstrated a significant increase in medium capillary and gel pores, and a reduction in large capillary pores in the RCA with an increase in soaking time. TG-DTA results indicated an increase in Ca(OH)2 content during the first 24 h and 48 h of treatment. However, after 72 h of treatment, the Ca(OH)2 content of the treated RCA decreased in all cases. XRD analysis revealed the appearance of a few additional ettringite peaks among the treated RCAs in all cases. SEM images demonstrated the presence of additional hydration products after treatment, which filled the pores and improved the surface texture. Furthermore, after treatment, the crushing value of all treated RCA decreased by 6.0–27.1%, whereas the water absorption decreased by 12.0–30.9% compared to the untreated RCA. Based on several experimental results, the formation of hydration products and the improvement mechanism of RCA from three different parent concretes by slurry treatment with different soaking durations were discussed. In conclusion, a prolonged impregnation time of 72 h yielded a dominant performance, effectively intensifying their inferior properties, regardless of the initial strength grade of parent concrete.

Effects of solar activity and geographic latitude on genetic homeostasis of human somatic cells

BACKGROUND: Associations between genetic stability of human somatic cells and solar activity across latitudes have been studied. A human buccal epithelium micronucleus test was selected as a method for evaluating genetic homeostasis.&#x0D; AIM: To assess effects of solar activity on the genetic stability of human somatic cells using the micronucleus test in buccal epithelium in relation to the geographical location of subjects.&#x0D; METHODS: Men aged 18 to 21 years with no harmful habits and taking no medication comprised the sample. Studies were conducted simultaneously in four cities of the Russian Federation: Sevastopol, Voronezh, Tomsk, and Khanty-Mansiysk. The effect of three types of solar flares, whose classification is based on changes in the amplitude of the thermal X-ray burst, was studied. Material for the cytogenetic study was collected on days 3, 7, and 10 after the solar flare. The human buccal epithelium micronucleus test was selected as a method to evaluate genetic homeostasis. At least 1,000 cells were examined on each preparation, among which the number of cells with micronuclei, perinuclear vacuoles, notches, “broken egg” and “tongue” type protrusions, karyorexis, karyolisis, and karyopyknosis was determined. In total, 495 thousand buccal epithelial cells were analyzed. Statistical processing of the data was performed using “Stadia” and “Statistica” software packages. Effecs of solar andlatitude on genetic homeostasis of somatic cells was performed using multivariate analysis of variance and two-factor analysis of variance with fixed effects.&#x0D; RESULTS: Solar activity affected the stability of the human genetic apparatus by increasing the influence of the city pollution and its geographical location on the number of cells with nucleus abnormalities. We also observed a combined effect of solar flare and season on the number of cells with nucleus aberrations. More nuclear anomalies were registered in the winter. We did not detect any difference in the number of cells with nucleus anomalies on the 3rd, the 7th, the 10th, and the 17th days after the flare suggesting no associations between solar activity and the number of cells with nuclear abnormalities.&#x0D; CONCLUSION: The highest number of cells with nucleus abnormalities is observed in Sevastopol reflecting with the greatest level of anthropogenic pollution of this city compared to the other locations. Solar activity increases the influence of the city pollution and its geographical location on the number of cells with nucleus abnormalities. The results obtained can be used in conducting a micronucleus test of human buccal epithelium and in planning measures to assess the genotoxicity of the environment.

Eutectoid decompositions in Ce-containing ABO3 perovskites: Part I, the case of cooperative growth in CeAlO3.

Oxidation of perovskite CeAlO3 results in the eutectoid transformation to CeO2 and Al2O3. This phase transformation was recorded using thermal gravimetric analysis, X-ray diffraction, and scanning transmission electron microscopy. Lamellar features in the resultant microstructure indicates cooperative growth. Processing conditions dictate the lamellae sizes, which can be as small as a few nanometers, and coarsen into large domains with additional high temperature annealing.

Constraining the magnetic field geometry of the millisecond pulsar PSR J0030+0451 from joint radio, thermal X-ray, andγ-ray emission

Context.With the advent of multi-wavelength electromagnetic observations of neutron stars – spanning many decades in photon energies – from radio wavelengths up to X-rays andγ-rays, it has become possible to significantly constrain the geometry and the location of the associated emission regions.Aims.In this work, we use results from the modelling of thermal X-ray observations of PSR J0030+0451 from the Neutron Star Interior Composition Explorer (NICER) mission and phase-aligned radio andγ-ray pulse profiles to constrain the geometry of an off-centred dipole that is able to reproduce the light curves in these respective bands simultaneously.Methods.To this aim, we deduced a configuration with a simple dipole off-centred from the location of the centre of the thermal X-ray hot spots. We show that the geometry is compatible with independent constraints from radio andγ-ray pulsations only, leading to a fixed magnetic obliquity ofα ≈ 75° and a line-of-sight inclination angle ofζ ≈ 54°.Results.We demonstrate that an off-centred dipole cannot be rejected by accounting for the thermal X-ray pulse profiles. Moreover, the crescent shape of one spot is interpreted as the consequence of a small-scale surface dipole on top of the large-scale off-centred dipole.

Phase Diagram of the MgF2–SrF2 System and Interactions of Magnesium and Strontium Fluorides with Other Fluorides

The phase diagram of the SrF2–MgF2 system has been studied by differential thermal analysis (DTA) and X-ray powder diffraction (XRD). The stability area of the compound SrMgF4 is very small, and its extent is about 20°С between 870 and 890°С. The formation of compounds by magnesium fluoride and strontium fluoride with other metal fluorides is considered in the M versus X coordinates, where M is the cumulative moment of the cation and X is the cation electronegativity. Two areas of compound formation were identified for each of the fluorides. Magnesium and strontium fluorides are amphoteric compounds in terms of the Lewis acid and base theory.

Study on the composite structure of cobalt-free oxides as cathodes for intermediate temperature solid oxide fuel cells (IT-SOFCs)

Summary: Solid Oxide Fuel Cells (SOFCs) represent a promising technology for efficient and clean energy conversion. This study focuses on the design and development of a novel cathode material for SOFCs, specifically exploring the use of a free-cobalt cathode within a composite structure. Investigating the structure of cobalt-free composites of Ba0.5Sr0.5FeO3-δ (BSF) and Ba0.5Sr0.5Fe0.8B0.2O3-δ (B=Cu, Zn) (BSFB) have been prepared and evaluated as cathodes for IT-SOFCs. The solid-state reaction was employed for generating and modifying the composite structure of the model system. The decomposition reaction and the formation of perovskite structure have been observed using thermal gravimetric analysis and X-ray diffraction. The study encompasses experimental procedures, data processing using GSAS software, and the application of the Rietveld method to achieve precise analysis results. Rietveld analysis outcomes offer intricate details about the crystal structure, encompassing crystal unit parameters, and scale factors. The solid-state reaction led to the reduction in the weight of the composite during the heating process. The decomposition reaction of oxides was generated between 650 to 950 oC. The average of total weight loss during the period treatment was achieved up to 18 % and the perovskite phase formed in the composite structure. A single-phase perovskite from a cubic structure with space group Pm-3m was demonstrated by all composite’s models. The lattice parameter and a unit cell volume were obtained from the model system of BSF, BSFC and BSFZ, respectively. This study explores the potential development of SOFCs technology with the hope of making a positive contribution to advancing clean and sustainable energy solutions in the future