Elemental Chemical Composition Research Articles

Positive impact of the architecture of the oxygen electrode based on LNO and CGO for solid oxide electrochemical cells

The Ruddlesden-Popper phase, strontium- and cobalt-free lanthanum nickelate, La2NiO4+δ (LNO), is a mixed-conducting oxide phase and a promising oxygen electrode for SOCs (solid oxide electrochemical cells), thanks to its high diffusion of oxygen and its surface exchange properties. The electrochemical performance is strongly related to the charge transfer at the triple phase boundaries in the surface path and the excorporation/incorporation reaction in the bulk path. In this context, this study explores a strategy to increase the number of active sites in LNO-based electrodes, by designing nanostructured active functional layers and incorporating gadolinium-doped ceria (CGO). Two architectural scenarios are proposed compared to a pure LNO reference: a uniform distribution of CGO in the volume of the LNO and a continuous compositional gradient, both fabricated for the first time by electrostatic spray deposition (ESD).These designs are investigated based on phase structure, microstructure, elemental chemical composition, and electrochemical properties using SEM-EDS, XRD, and electrochemical impedance spectroscopy. Polarization resistance values are discussed as a function of the distribution of contact points in the electrode volume and LNO crystallization. The results suggest that the presented approach to achieve CGO: LNO-based gradient electrodes allows controlling the localization of the interfaces between the two phases, thereby optimizing charge transfer.

Enhanced Cyanide Oxidation to Cyanate via Photocatalytic Ozonation: Comparing Sol–Gel and Hydrothermal Synthesis of BiVO4 Catalysts

Bismuth vanadate has been reported as a promising active semiconductor for visible light harvesting. However, the rapid recombination of charge carriers has limited its photocatalytic properties. As an alternative route to treat contaminated water containing cyanide ions, photoactivated BiVO4 in combination with ozone has been investigated. BiVO4 photocatalysts were synthesized by microwave-assisted hydrothermal method, as well as by sol–gel, obtaining the monoclinic crystalline structure and a band gap of ~ 2.5 eV by XRD and UV–Vis DRS. The morphological analysis, elemental chemical composition, BET surface area, stability, and photoluminescence characteristics were carried out for both samples. Although the majority composition belongs to BiVO4, the presence of secondary phases was confirmed by XPS. The BiVO4 obtained by sol–gel (sol–gel BVO) exhibited superior photocatalytic performance with a lower reaction time (15 min) to oxidize free cyanide under visible-light radiation in combination with ozone. The degradation kinetics is described by pseudo-zero-order kinetics, and the rate constant (k0) of BiVO4 synthesized by microwave-assisted hydrothermal method was found to be the lower of the two. The high efficiency of the photocatalytic ozonation for the removal of free cyanide can be ascribed to a combination of two oxidation systems and the synergy of both processes.

Chemical composition and properties of Ski wax: A comprehensive analysis of fluorinated, non-fluorinated, and bio-based waxes

This study analyzes the chemical composition and thermal properties of various ski wax materials, including fluorinated, non-fluorinated petroleum-based, and bio-based waxes. Advanced characterization techniques (FTIR, EDS, and DSC) were used to investigate the chemical functionality, elemental composition, and thermal behavior of these waxes. Fluorinated powder waxes were found to be composed almost entirely of fluorocarbons, while solid fluorinated waxes are primarily hydrocarbons with minimal fluorine content. Bio-based waxes exhibit unique ester and carboxylic acid functional groups. Different brands, models, and suggested temperature uses of waxes within the same physical and chemical type show similar chemical compositions. While petroleum-based compared to bio-based waxes show a significant difference in chemical structure. EDS analysis identified silicon, magnesium, and aluminum in certain waxes, possibly indicating the use of additives. DSC results showed similar thermal behavior at sub-freezing temperatures. This research lays the groundwork for understanding ski wax material science and opens up new avenues for future investigation and innovation in the ski and ski wax industry.

Comparison of ex-situ solid and liquid iodine doping methods at different temperatures to improve electrical properties of polythiophene nanostructure films synthesized by atmospheric pressure plasma process

Despite advancements in research on conducting polymers, obtaining stable conductivity in thin films remains challenging. Although ex-situ iodine (I2) doping methods have exhibited promise, they often result in unstable conductivity with increasing exposure time. This study aimed to produce polythiophene (PTh) nanostructure films with stable electrical conductivity through optimized ex-situ I2-doping techniques using a newly fabricated atmospheric pressure plasma reactor for PTh deposition. I2 charge carriers in the form of solid and liquid were separately incorporated into the PTh at room temperatures and 60 °C. FE-SEM, EDS, and FT-IR revealed an enhanced molecular structure, the distribution of element and functional chemical composition of the doped PTh nanostructure films, respectively. Compared to solid I2 doping, the liquid-doped PTh exhibited improved electrical conductivity and stable conductivity over a long period. The results also proved promising for reliable applications in electronic devices, making ex-situ liquid I2 doping a good technique.

Valuable Ca/P Sources Obtained from Tuna Species’ By-Products Derived from Industrial Processing: Physicochemical and Features of Skeleton Fractions

The global tuna canning industry generates substantial volumes of by-products, comprising 50% to 70% of the total processed material. Traditionally, these by-products have been utilized in low-value products such as fish oils and fishmeal. However, there is significant potential to extract high-value compounds from these by-products, such as calcium phosphates (CaP), which can have pharmaceutical, agricultural and biotechnological applications. This work explores the potential of tuna canning by-products, particularly mineral-rich fractions (central skeleton, head and fish bones) as sources of calcium phosphates (CaP), offering a sustainable alternative to conventional synthetic derivatives within a circular bioeconomy framework. By-products from two of the most exploited species (yellowfin and skipjack) were subjected to enzymatic hydrolysis and chemical extraction, followed by controlled calcination to obtain CaP. The content of organic matter, nitrogen, total proteins, lipids and amino acids in the cleaned bones, as well as the main chemical bonds, structure and elemental composition (FT-Raman, XRD, XRF) were evaluated. Results indicated that the highest recovery yield of wet bones was achieved using the chemical method, particularly from the dorsal and caudal fins of yellowfin tuna. The proximal composition, with ash content ranging from 52% to 66% and protein content varying between 30% and 53%, highlights the potential of tuna skeleton substrates for plant growth formulations. Furthermore, variations in crystalline structures of the substrates revealed significant differences depending on the by-product source and species. XRD and Raman results confirmed a monophase calcium phosphate composition in most samples from both species, primarily based on hydroxyapatite (central skeleton, caudal and dorsal fin) or whitlockite/β-tricalcium phosphate (viscera), whereas the heads exhibited a biphasic composition. Comparing the species, yellowfin tuna (YF) exhibited a hydroxyapatite structure in the branchial arch and scales, while skipjack (SKJ) had a biphasic composition in these same regions.

Study of Surface Repair Materials for Aged Silicone Rubber Insulators

The aging phenomenon of silicone rubber insulators can bring great safety risks for the stable operation of high-voltage transmission lines. To avoid the significant costs and prolonged downtime associated with completely replacing insulating equipment, our research described in this paper proposes a surface repair material for aged silicone rubber insulators using α, ω-dihydroxy-polydimethylsiloxane as the matrix. The material was, after preparation, uniformly applied to the surface of insulators that had been in grid operation for more than 14 years. The chemical structure, elemental composition and surface morphology of the insulator surfaces were characterized both before and after repair. Our research described here also examined the changes in mechanical properties, insulating resistivity, water repellency and adhesion strength of the insulators. The data showed that the functional group types and element contents on the surface of the repaired silicone rubber insulators were restored to those of the new insulators, and the surface and internal cracks were also effectively repaired. Moreover, the water-repellent, mechanical, and electrical properties underwent a notable enhancement. The robust adhesion between the repair material and the deteriorated surface resulted in the formation of a stable and robust adhesive interface. The results demonstrated that the materials created for the purpose of repair in our research had the capability to efficiently enhance the performance of aged insulators. Furthermore, we suggest this study presented a novel path toward addressing the predicament of aging insulation equipment.

Structural, optical, and dielectric properties of double perovskite NdBaFeTiO6

NdBaFeTiO6 compound was synthesized successfully through solid-state reaction method. The compound was found to have a crystalline cubic double perovskite (DP) structure with space group Pm-3m by XRD analysis. Structural refinement was performed to investigate the detail of the structure and was found consistent with the experimental results. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and elemental mapping were used to analyze the morphology and elemental composition, revealing the existence of expected chemical composition and uniform distribution of elements within the material. FTIR and Raman spectroscopic techniques were utilized to investigate the vibrational modes and bonding configurations present in the synthesized sample. XPS spectra confirms the existence of photoelectron peaks associated with constituent elements, and also reveals the lattice oxygen and oxygen vacancies. Optical absorbance measurements showed that this material possesses a significant band gap energy of around 4eV, making it a promising candidate for a variety of technological applications. The electrical properties of this double perovskite were investigated using dielectric measurements, both frequency and temperature dependent. At low temperatures, the dielectric constant behaves independently. At higher temperatures, the thermal energy sufficiently enhances the mobility of charge carriers, thereby causing an elevation in dielectric constant of the order of 104 and 103 at low and high frequencies respectively. Moreover, the temperature dependence of the dielectric constant varies for different frequencies.

Impact of Formwork Materials on Concrete Surface Quality

Given the functional and aesthetic quality expected from concrete surfaces, this study investigated the influence of different formwork materials on their surface density, porosity, voids, and elementary chemical composition by relying on X-ray Microtomography (μCT), Scanning Electronic Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). The formwork materials assessed were galvanized steel, regular plywood (pink), marine plywood, polyvinyl chloride (PVC), and silicone. μCT showed that distinct formwork affected the surface density of the concrete. In this case, specimens cast within silicone and marine plywood had similar pore volumes although different pore sizes, whereas PVC led to the highest pore volume with small pore sizes. Galvanized steel and regular plywood resulted in similar porosity. SEM showed that the concrete surfaces produced with marine plywood formwork had the highest void content. EDS identified surface products resulting from the contact of concrete with the different formwork materials, suggesting the potential migration of chemical elements. This research significantly contributes to optimizing formwork material selection and enhancing concrete quality and durability. Moreover, it establishes a foundation for further investigations into how formwork materials affect concrete surfaces and the pathological manifestations potentially arising from the molding process.

Experimental analysis of free-standing and substrate-constrained Ga-doped ZnO nanostructured thermoelectric films

Developing thermoelectric films without substrates—free-standing films—eliminates substrate-induced effects on performance and meets the flexibility requirements of emerging wearable thermoelectric applications. This study investigates Gallium-doped Zinc Oxide (GZO), composed of abundant and non-toxic elements, to fabricate a substrate-free GZO film via 3D printing and compares its structural, chemical, and thermoelectric properties with those of a substrate-constrained GZO film produced through chemical deposition. Both films exhibited uniform crystal structures and phase purity; however, the substrate-constrained film displayed additional diffraction peaks, suggesting potential substrate interactions. The 3D-printed free-standing film effectively eliminated the tensile stresses observed in the substrate-constrained film. FE-STEM analysis revealed nanostructures with homogeneous elemental distribution in both films, though the substrate-constrained film showed discontinuities, such as pores, likely caused by post-deposition annealing treatment. XPS analysis highlighted differences in chemical states and elemental compositions between the films, influenced by fabrication methods, substrate-induced stresses, and surface energy mismatches. The free-standing GZO film developed through 3D printing exhibited a more balanced incorporation of Zn and O, as it was not subject to substrate or post-deposition annealing constraints. Consequently, it demonstrated a 14 % increase in electrical conductivity and a 91 % improvement in the Seebeck coefficient compared to the substrate-constrained film, resulting in a higher room-temperature power factor of 261 nW/m·K2. These findings underscore the potential of 3D-printed free-standing GZO films to advance thermoelectric applications, offering a promising alternative to overcome the challenges of substrate-constrained films and further drive innovation in the field.

Diffraction peak identification and correction in EDXRF spectroscopy

Energy dispersive X-ray fluorescence (EDXRF) spectroscopy is an analytical technique often used to create maps of the elemental chemical composition. The fluorescence signal can be influenced by X-ray diffraction peaks, a phenomenon that can lead to difficulties or errors in interpreting spectral peaks. However, diffraction can also be useful if we successfully separate it from the fluorescence signal. In this paper, we propose different methods to deal with the diffraction peaks by using the signals obtained from a spectrometer equipped with two detectors. These methods were tested on a thin section of a rock sample to show their effectiveness in processing diffraction peaks. Each method showed its ability to deal with the diffraction peaks in a more or less effective way and each has its own limitations. The latter have to be taken into account when analyzing the EDXRF signal, whether in a geological context or in any other context.

Determination of rare earth elements in synthetic calcium phosphates by high-resolution continuum source electrothermal atomic absorption spectrometry

Ceramic, cement and composite biomaterials have been developed based on hydroxyapatites (HA) and tricalcium phosphates (TCP), which are analogous in phase and chemical composition to the mineral component of bone tissue. The crystal structures of HA and TCP are arranged in isomorphic substitutions. Recently, research has focused on the modification of HA and TCP structures with ions of various metals, including rare earth ions (REEs), with the aim of creating materials with a range of beneficial properties for medical applications. REEs are known to have a number of useful properties, including antibacterial, antitumour, catalytic, magnetic and luminescent properties. The replacement of some of the Ca ions in the structures of HA and TCP with REE ions therefore makes it possible to obtain a material with biocompatibility and biological activity, giving it the required properties depending on the REE used and its concentration. In order to achieve the specified properties, it is necessary to control not only the structure (phase composition, lattice parameters of the powders) and the presence of characteristic functional groups, but also the chemical elemental composition. Modifications of hydroxyapatites and tricalcium phosphates containing from one to several different alloying elements are currently being developed. Various analytical methods are used for this purpose, including X-ray, atomic emission and a number of others. This article is devoted to the study of the analytical capabilities of the method of atomic absorption spectrometry with electrothermal atomization and a continuous spectrum source in relation to the determination of Eu and Yb in hydroxyapatites and tricalcium phosphates. The article considers the optimal conditions and modes of analysis, including temperature-time programs, the use of modifiers, the construction of calibration curves, and other factors that can be adjusted for more precise results. The results demonstrated the possibility of simultaneous determination of both Eu and Yb in the concentration range of 0.09 to 2 wt.%, with a relative standard deviation of less than 6 rel.%.

Chemical elemental composition and human taphonomy: A comparative analysis between skeletonised and preserved individuals from six Portuguese public cemeteries

IntroductionIn Portugal, it is common practice to reuse burial graves in cemeteries with exhumations occurring after a minimum period of three years after entombment. However, if the human remains still retain soft tissues when the grave is opened, inhumations must continue for successive periods of two years until complete skeletonization is achieved. For the past decade, several Portuguese public cemeteries have been struggling with the lack of burial space mainly due to a slow cadaveric decomposition. As such, this work aims to understand if the chemical elemental concentrations found in the depositional environment of deceased individuals is influencing human taphonomy. MethodsA total of 112 soil samples were collected from graves of five Portuguese public cemeteries and the concentration of 28 chemical elements was measured by inductively coupled plasma mass spectrometry (ICP-MS). A total of 56 head hair samples and 19 fingernail samples were also collected from cadaveric remains and analysed for the same purpose. ResultsOverall, all matrices showed statistically significant differences (p < 0.05) between skeletonised and preserved individuals. Although it was considered that the preserved bodies would display higher elemental concentrations than the skeletonised ones, this hypothesis was not confirmed. ConclusionsThe authors believe that changes in the burial conditions over time may have enable the disintegration of soft tissues even if they were initially preserved due to the presence of chemical elements. Similar studies on a global scale should be considered as they could bring together distinct perspectives and lead to more comprehensive and innovative solutions for cemetery management.

Определение литологического состава осадочных пород для построения объемной модели по данным ГИС

The features of the lithological composition of productive sediments and their consideration in the petrophysical modeling of a volumetric model based on a GIS complex are considered. It is noted that on the basis of X-ray spectral and granulometric analysis, it is possible to obtain reliable information about the structure, texture, component and mineral composition in order to clarify the petrophysical characteristics of the rocks under study. Using the example of two hydrocarbon deposits “K” and “N” the results of determining the lithological composition of sedimentary rocks from core from different age terrigenous deposits are discussed in order to build a petrophysical model of the entire well section, taking into account the areas of lack of information from direct studies (sludge and core). Electron microscopy and X-ray diffraction analysis are used to study finely dispersed (clay, siliceous, carbonate, etc.) rocks, which are especially important for accurate diagnosis of the mineral composition of rocks. In addition to the features of the geological structure of the deposit, the quantity and quality of the initial information largely determine the methods of constructing the model and the results obtained. The results of X-ray spectral analysis made it possible to determine the composition of chemical elements and the amount of each element in the sample. Information about the mineral composition of rocks and the lithological differences identified at the first stage are distributed to the part of the section where there is no or insufficient information on the core or sludge. The information obtained on the lithological composition of sediments gives the most complete picture of the geological structure of the section opened by the well and is further used as the basis of a volumetric model based on the data of geophysical surveys of GIS wells.

Manganese diluted TlInS2 layered semiconductor: Optical, electronic and magnetic properties

Manganese–doped TlInS2 (TlInS2+Mn) layered semiconductors with different doping concentrations of about 0.1 and 0.3 at. percent were investigated. Photo–induced current transient spectroscopy (PICTS) measurements in the temperature range of 80 and 300 K have been made for identifying energy levels related to Mn dopant within the electronic bandgap of TlInS2+Mn crystal. Optical absorption spectra in the photon energy range of ∼1.8–3.1 eV have been extracted by fitting the transmittance spectra of TlInS2+Mn recorded at the temperatures varied from ∼40–300 K. A redshift trend of the absorption edge with increasing of temperature was observed. On the other hand, a blue shift in the absorption edge with Mn doping was observed in the absorption spectra. The Mn dopant induced photoluminescence (PL) was also investigated in the visible region ranging from 320 to 960 nm. Seven peaks were observed in the PL spectra of Mn doped TlInS2 crystal in the regions both ∼960–620 nm (∼1.3–2 eV) and ∼620–320 nm (∼2–3.8 eV) due to the electronic states of Mn ions. Laser–induced breakdown spectroscopy (LIBS) technique was applied to establish of the elemental chemical composition and to confirm presence of each constituent element in TlInS2:Mn. The dc magnetization measurements of TlInS2+Mn performed in a wide temperature range of ∼5 and ∼300 K revealed different (diamagnetic and paramagnetic states) magnetic phases inside the studied temperature range. The X–band electron paramagnetic resonance (ESR) experiments were carried out in the low–temperature phase of TlInS2+Mn to probe the structure of Mn centers in TlInS2. The measurements revealed that the ESR spectrum changes drastically in the low–temperature phase of TlInS2+Mn bulk sample. Finally, a detailed density functional theory (DFT) based computational investigation of electronic band structures, density of states and optical properties of TlInS2+Mn compound has been performed. The results of ab–initio calculations are discussed for three possible states when the manganese atom was doped by replacing either the Tl, In or S atoms in the unit cell of TlInS2. Additionally, the effect of interstitial Mn dopant on the electronic structure and optical properties of TlInS2 material has been simulated.

Role of Humic Substances in the (Bio)Degradation of Synthetic Polymers under Environmental Conditions

Information on the detection of the presence and potential for degradation of synthetic polymers (SPs) under various environmental conditions is of increasing interest and concern to a wide range of specialists. At this stage, there is a need to understand the relationship between the main participants in the processes of (bio)degradation of SPs in various ecosystems (reservoirs with fresh and sea water, soils, etc.), namely the polymers themselves, the cells of microorganisms (MOs) participating in their degradation, and humic substances (HSs). HSs constitute a macrocomponent of natural non-living organic matter of aquatic and soil ecosystems, formed and transformed in the processes of mineralization of bio-organic substances in environmental conditions. Analysis of the main mechanisms of their influence on each other and the effects produced that accelerate or inhibit polymer degradation can create the basis for scientifically based approaches to the most effective solution to the problem of degradation of SPs, including in the form of microplastics. This review is aimed at comparing various aspects of interactions of SPs, MOs, and HSs in laboratory experiments (in vitro) and environmental investigations (in situ) aimed at the biodegradation of polymers, as well as pollutants (antibiotics and pesticides) that they absorb. Comparative calculations of the degradation velocity of different SPs in different environments are presented. A special place in the analysis is given to the elemental chemical composition of HSs, which are most successfully involved in the biodegradation of SPs. In addition, the role of photo-oxidation and photoaging of polymers under the influence of the ultraviolet spectrum of solar radiation under environmental conditions on the (bio)degradation of SPs in the presence of HSs is discussed.

Nd Isotopic Equilibration During Channelized Melt Transport Through the Lithosphere: A Feasibility Study Using Idealized Numerical Models

AbstractThis study is motivated by the observed variability in trace element isotopic and chemical compositions of primitive (Si52 wt %) basalts in southwest North America (SWNA) during the Cenozoic transition from subduction to extension. Specifically, we focus on processes that may explain the enigmatic observation that in some localities, basalts with low Ta/Th, consistent with parental melts in a subduction setting, have signatures consistent with continental lithospheric mantle (CLM). In locations with the oldest CLM (Proterozoic and Archean), Cenozoic basalts with low Ta/Th have well below zero. We model channelized magma transport through the CLM using simple 1D transport models to explore the extent to which diffusive and reactive mass exchange can modify Nd isotopic compositions via open system melt‐wallrock interactions. For geologically reasonable channel spacings and volume fractions, we quantify the reactive assimilation rates required for incoming melt with a different than the wall‐rock to undergo a substantial isotopic shift during 10 km channelized melt transport. In the presence of grain boundaries, enhanced diffusion between melt‐rich channels and melt‐poor surrounding rock contributes to isotopic equilibration, however this effect is not enough to explain observations; our models suggest a significant contribution from reactive assimilation of wall‐rock. Additionally our models support the idea that the observed covariability in Ta/Th and in Cenozoic basalts cannot be attributed to transport alone and must also reflect the transition from subduction‐related to extension‐related parental melts in SWNA.

ТҮРКІСТАН ОБЛЫСЫНЫҢ ЛАНДШАФТТАРЫНЫҢ ТОПЫРАҚ ЖАМЫЛҒЫСЫ АНТРОПОГЕНДІК ФАКТОРЛАРДЫҢ ӘСЕРІ САЛДАРЫНАН ЛАСТАНУЫ

Turkestan region is located in the south of Kazakhstan and is one of the industrially and agri-culturally developed regions of the republic. As the intensity of nature management in Turkestan region increases, pollution occurs under the influence of anthropogenic factors. Taking into account anthropogenic factors, the composition of chemical elements of the soil cover in genetic layers was studied in typical natural areas of the landscape system; and soil sections were made to determine the composition. The concentrations of chemical elements (C, O, Na, Mg, Al, Si, K, Ca, Ti, Fe, Pb, As, Cu, Zn, Ni, Co, V, Tl, Mn, and Sr) were analyzed based on the results of the analysis of samples from soil sections. The amount of chemical elements of the soil cover was determined using the Spectroscan MAX GF-2E device. The obtained data were statistically processed using the Microsoft Excel program. Chemical analysis of the soil cover (Pb, Cu, Zn, As, and Cr) showed that the chemical elements exceed the maximum allowable concentration. The results of the study are the basis for developing recommendations for solving problems related to the pollution of landscapes due to the impact of anthropogenic factors on the soil cover.

Halogenated-edge polymeric semiconductor for efficient spin transport.

Organic semiconductors (OSCs) are featured by weak spin-orbit coupling due to their light chemical element composition, which enables them to maintain spin orientation for a long spin lifetime and show significant potential in room-temperature spin transport. Carrier mobility and spin lifetime are the two main factors of the spin transport performance of OSCs, however, their ambiguous mechanisms with molecular structure make the development of spintronic materials really stagnant. Herein, the effects of halogen substitution in bay-annulated indigo-based polymers on carrier mobility and spin relaxation have been systematically investigated. The enhanced carrier mobility with an undiminished spin lifetime contributes to a 3.7-fold increase in spin diffusion length and a record-high magnetoresistance of 8.7% at room temperature. By analyzing the spin-orbit coupling and hyperfine interaction, it was found that the distance of the substitution site from the conjugated center and the nitrogen atoms in the molecules play crucial roles in spin relaxation. Based on the above results, we proposed a molecular design strategy of halogen substitution far from conjugate center to enhance spin transport efficiency, presenting a promising avenue for advancing the field of organic spintronics.

MOF-derived In2O3 nanotubes modified by Bi2Se3 for enhanced NOx detection at room temperature

The In2O3/Bi2Se3 composite was synthesized by loading Bi2Se3 flakes on MOF-derived In2O3 tubes through solvothermal method. The chemical composition, morphology and chemical state of elements for composite were examined through XRD, SEM, TEM and XPS. The In2O3/Bi2Se3 composite exhibited significantly enhanced sensing performance compared to pure In2O3 and Bi2Se3. The response value of In2O3/Bi2Se3 composite is 844 for 30 ppm NOx at 25 °C, which is 21 times that of pure In2O3, and it also displays shorter response /recovery time and lower detection limit. The remarkable gas-sensing properties of In2O3/Bi2Se3 composite are attributable to its large specific surface area, rapid electron mobility, abundant oxygen vacancies and the presence of n-n heterostructure. The adsorption behavior of NOx gas on the surface of In2O3/Bi2Se3 was explored using the in-situ diffuse reflectance infrared Fourier transform (DRIFT) spectrum.

The impact of pressure rate on the physical, structural and gamma-ray shielding capabilities of novel light-weight clay bricks

The present study focuses on investigating the gamma-ray protection features of clay bricks for potential use in radiation shielding fields. The study examined the physical and structural features that affect the performance of these stones in shielding γ-rays. The density (ρ, g/cm3) of the clay bricks samples was measured utilizing the MH-300A density meter. Additionally, the mineral structure within the annealed pressed clay samples was identification the XRD spectrometry. Moreover, the morphology and elemental chemical composition for the annealed bricks were examined using a Thermo Scientific Prisma E, USA field emission Scanning Electron Microscope (SEM) in conjunction with Energy Dispersive X-ray Spectroscopy. Besides, the shielding features of the clay bricks were analyzed using the experimentally measurements (by NaI (Tl) scintillation detector), XCOM software, and Monte Carlo Simulation over the γ-ray energy interval of 0.033–1.332 MeV. The findings of the study indicate that an increase in the pressure rate within the clay bricks samples leads to the rise in their density (from 1.62 to 1.87 g/cm3). This increase in density is accompanied by a decline in both porosity (Φ, %) (from 34.75 to 26.21 %) and water absorption (K, %) (from 26.21 to 14.74 %) factors. Furthermore, the increase in pressure rate from 7.61 to 114.22 MPa also results in an increase in the linear attenuation coefficient (μ, cm−1) of the clay bricks under study. This is achieved by increasing the μ values from 0.39 to 0.43 cm−1, from 0.13 to 0.15 cm−1, and from 0.09 to 0.10 cm−1, at 0.081, 0.511 and 1.173 MeV, respectively. The synthetic bricks offer a lead-free and efficient option for protection, making them ideal for use in nuclear facility start-ups or in areas with radiation exposure.