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Recently, Strontium oxide (SrO) nanoparticles (NPs) and hybrids outperformed older commercial catalysts in terms of catalytic performance. Herein, we present a microwave-assisted easy in situ solution casting approach for the manufacture of strontium oxide nanoparticles doped within a naturally occurring polymer, chitosan (CS), at varying weight percentages (2.5, 5, 10, 15, and 20 wt.% SrO/chitosan). To construct the new hybrid material as a thin film, the produced nanocomposite solutions were cast in petri dishes. The aim of the research was to synthesize these hybrid nanocomposites, characterize them, and evaluate their catalytic potential in a variety of organic processes. The strontium oxide-chitosan nanocomposites were characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM) techniques. All the results confirmed the formation of chitosan–strontium oxide nanocomposite. FTIR spectrum of nanocomposite showed the presence of a characteristic peak of Sr-O bond. Furthermore, XRD revealed that SrO treatment increased the crystallinity of chitosan. The particle size was calculated using the Debye–Scherrer formula, and it was determined to be around 36 nm. The CS-SrO nanocomposite has been proven to be a highly efficient base promoter for the synthesis of 2-hydrazono [1,3,4]thiadiazole derivatives. To optimize the catalytic method, the reaction factors were investigated. The approach has various advantages, including higher reaction yields, shorter reaction durations, and milder reaction conditions, as well as the catalyst’s reusability for several applications.

This study investigates the structural modifications and crystallization behavior of glasses in the system xSrO–(40 − x)SiO 2 –30CaO–30B 2 O 3 (x = 0, 10, 20, 30, 35 mol%). The amorphous nature of as-prepared glasses was confirmed through X-ray diffraction analysis. Upon thermal treatment, controlled crystallization led to the formation of apatite, wollastonite, and strontium silicate crystalline phases, as evidenced by XRD and TEM analyses. The progressive substitution of SrO for SiO 2 resulted in increased concentration of non-bridging oxygen atoms (NBO) in both silicate (SiO 4 ) and borate (BO 4 ) structural units, as revealed by FTIR and NMR spectroscopy. The presence of NBOs promoted crystallization processes and facilitated the formation of nano-crystalline species. The formation of biocompatible crystalline phases, particularly wollastonite (CaSiO 3 ) and apatite (CaSrBO 4 ), suggests potential applications in orthodontic and orthopedic fields.

Polymeric films made from chitosan (CS) doped with metal oxide (MO = cobalt (II) oxide and strontium oxide) nanoparticles at different concentrations (5, 10, 15, and 20% wt. MO/CS) were fabricated with the solution cast method. FTIR, SEM, and XRD spectra were used to study the structural features of those nanocomposite films. The FTIR spectra of chitosan showed the main characteristic peaks that are usually present, but they were shifted considerably by the chemical interaction with metal oxides. FTIR analysis of the hybrid chitosan-CoO nanocomposite exhibited notable peaks at 558 and 681 cm−1. Conversely, the FTIR analysis of the chitosan-SrO composite displayed peaks at 733.23 cm−1, 810.10 cm−1, and 856.39 cm−1, which can be attributed to the bending vibrations of Co-O and Sr-O bonds, respectively. In addition, the SEM graphs showed a noticeable morphological change on the surface of chitosan, which may be due to surface adsorption with metal oxide nanoparticles. The XRD pattern also revealed a clear change in the crystallinity of chitosan when it is in contact with metal oxide nanoparticles. The presence of characteristic signals for cobalt (Co) and strontium (Sr) are clearly shown in the EDX examinations, providing convincing evidence for their incorporation into the chitosan matrix. Moreover, the stability of the nanoparticle-chitosan coordinated bonding was verified from the accurate and broadly parametrized semi-empirical tight-binding quantum chemistry calculation. This leads to the determination of the structures’ chemical hardness as estimated from the frontier’s orbital calculations. We characterized the dielectric properties in terms of the real and imaginary dielectric permittivity as a function of frequency. Dielectric findings reveal the existence of extensive interactions of CoO and SrO, more pronounced for SrO, with the functional groups of CS through coordination bonding. This induces the charge transfer of the complexes between CoO and SrO and the CS chains and a decrease in the amount of the crystalline phase, as verified from the XRD patterns.

Heat transfer fluids such as therminol have long been utilized in a range of applications. Increasing the thermophysical properties of therminol is one of the promising strategies to improve the performance of therminol-based systems and overcome the disadvantages of poor thermal performance. Nanofluids transport heat more effectively than ordinary conventional fluids. The goal of this work is to evaluate the influence of lanthanum oxide-strontium oxide (LaO-SrO) nanocomposite on the thermal conductivity and viscosity of therminol experimentally. The chemical co-precipitation approach was used to synthesis the LaO-SrO nanocomposite. X-ray diffraction (XRD) and UV-Visible spectroscopy were used to evaluate the structural and optical characteristics of the nano samples. LaO-SrO based nanofluid was prepared with therminol as the base fluid. Thermal conductivity studies of LaO-SrO nanofluids were carried out in detail at different weight percentages of LaO-SrO nanocomposite at varying temperatures. The nanofluid exhibit an increase in thermal conductivity and viscosity as compared with base fluid therminol. The viscosity shows a significant decrease as the temperature rises from 25°C to 50°C. Results show that LaO-SrO nanofluids can be used as a better alternative for conventional fluids in heat transfer applications.

This study investigates polymer membranes composed of polyvinyl alcohol (PVA) and poly (vinyl pyrrolidone) (PVP) embedded with metal oxides, specifically Strontium oxide (SrO) and Lanthanum oxide (La2O3). Composite films of PVA-PVP-SrO, PVA-PVP- La2O3, and PVA-PVP-SrO–La2O3 were developed using an ultrasound-assisted casting technique. X-ray diffraction (XRD) analysis revealed that these polymer membranes exhibit both semi-crystalline and amorphous characteristics, with crystalline peaks of SrO and La2O3 indicating modifications in their structural properties. The electrical properties were evaluated using an I-V source meter and impedance spectroscopy. Physical properties of the materials were studied to understand their behaviour of stress and strain. Young’s Modulus measurements revealed that PVA-PVP- La2O3 achieved the highest elongation value (ɛ) of 145.5. Thermal conductivity was measured using the transient hot wire method, indicated that PVA-PVP-SrO–La2O3 exhibited superior thermal conductivity compared to the other composites, achieving a value of 16.129 W/(m−1 K−1).

In this study, we describe the characterization and applicability of the liquid crystal (LC) system of brush-coated indium strontium oxide (InSrO) film. To achieve this aim, the film curing temperature was adjusted and the surface morphology was examined using atomic force microscopy and corresponding line profile data. In particular, we revealed a nano/microgroove anisotropic surface structure on the film after curing at 230°C, which was derived from the shear stress generated during movement of the wet brush hairs and subsequent active thermal oxidation of InSrO. In addition, x-ray photoelectron spectroscopy confirmed the presence of a well-formed InSrO film on the substrate. The film also exhibited hydrophilic properties at higher curing temperatures along with an amorphous structure. The InSrO film represented high optical transmittance to the LC system, and we confirmed the uniform and homogeneous LC alignment state using polarized optical microscopy and pre-tilt angle analyses. The oriented anisotropic film structure induced the alignment of LCs on the surface through geometric constraints. The InSrO film also exhibited advanced electro-optical performance with a fast response time and low operating voltage compared to the polyimide layer conventionally used in LC systems. From these results, we expect that brush-coated InSrO film will be a good alternative in advanced LC systems.

The production of hydrogen from glycerol steam reforming (GSR) was studied over a series of Co–Mg–Sr (CMS) mixed oxide catalysts. Co-precipitation method was adopted to prepare catalysts by varying the molar ratios of MgO–SrO and keeping Co 3 O 4 content constant. The physico-chemical properties of the samples were investigated by BET surface area, X-ray diffraction, hydrogen chemisorption, temperature programmed reduction, temperature programmed desorption of CO 2 , Raman spectroscopy and CHNS analysis. The reforming activity depended on the composition of the metal oxides. The catalyst with Co–Mg–Sr molar ratio of 3:1:1 exhibited the highest catalytic activity at 700 °C. Glycerol was completely converted to gaseous products and showed 72% hydrogen yield. Catalytic activity of the catalysts was explained on the basis of cobalt particle size, basicity and metal oxides interaction. The catalysts basicity originating from MgO–SrO is also playing an important role in GSR. The present catalyst activity was unaltered even after 100 h of time on stream analysis. Graphic Abstract

A pivotal challenge posed by unconventional superconductors is to unravel how superconductivity emerges upon cooling from the generally complex normal state. Here, we use nonlinear magnetic response, a probe that is uniquely sensitive to the superconducting precursor, to uncover remarkable universal behaviour in three distinct classes of oxide superconductors: strontium titanate, strontium ruthenate, and the cuprate high- T c materials. We find unusual exponential temperature dependence of the diamagnetic response above the transition temperature T c , with a characteristic temperature scale that strongly varies with T c . We correlate this scale with the sensitivity of T c to local stress and show that it is influenced by intentionally-induced structural disorder. The universal behaviour is therefore caused by intrinsic, self-organized structural inhomogeneity, inherent to the oxides’ perovskite-based structure. The prevalence of such inhomogeneity has far-reaching implications for the interpretation of electronic properties of perovskite-related oxides in general. The understanding of how superconductivity emerges from a complex normal state remains elusive in unconventional superconductors. Here, Pelc et al. report exponential temperature dependence of the diamagnetic response in the normal state with a characteristic temperature scale, universally existing in three classes of oxide superconductors.

In this research, the study of two dopants, strontium oxide and manganese oxide were thoroughly investigated based on the elastic properties for the purpose of high strength glass application. The melt quenching technique method was used to synthesize two series of borotellurite glass systems doped with manganese and strontium. Elastic measurement, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the prepared glass samples. The increment of molar volume confirmed the theory that molar volume is inversely proportional to the density parameters. A broad hump was observed during XRD as the samples shows pure amorphous nature. In FTIR, the vibrations of the functional group of the tellurite network were recorded such as TeO 4 trigonal bipyramids and TeO 3 trigonal pyramids, by addition of both dopants. On the other hand, ultrasonic velocity was used to determine the elastic moduli of the glass such as bulk modulus, shear modulus, longitudinal modulus, Young’s Modulus, microhardness and Poisson’s ratio which showed decreasing and increasing trends with the increased concentration of MnO 2 and SrO respectively. It is also inferred that strontium oxide has better elastic properties than manganese oxide.

The aim of this experiment was to determine the effect of the addition of strontium oxide on the recrystallization of zirconium silicate when adding strontium oxide to the glaze composition. Zirconia glazes (four different contents) were prepared, to which strontium oxide was added in amounts of 0, 1, 3, 6, and 12 mass% SrO. The characteristic temperatures of the raw glazes were measured, based on which the maximum firing temperatures were determined. The fired glazes were subjected to a study of their phase compositions and an observation of their microstructures. An analysis of the characteristic temperatures showed a fluxing effect, but it was not as strong for all glazes. Differences in the amount of the crystalline phase of zirconium silicate obtained in the fired glazes, as well as the partial transition of zirconium silicate to the amorphous phase, were observed. Observations of the microstructure clearly indicated an increase in the homogeneity of the distribution of zirconium silicate.