Morphology Of Samples Research Articles

Improved visualisation of ACP-engineered osteoblastic spheroids: a comparative study of contrast-enhanced micro-CT and traditional imaging techniques

This study investigates osteoblastic cell spheroid cultivation methods, exploring flat-bottom, U-bottom, and rotary flask techniques with and without amorphous calcium phosphate (ACP) supplementation to replicate the 3D bone tissue microenvironment. ACP particles derived from eggshell waste exhibit enhanced osteogenic activity in 3D models. However, representative imaging of intricate 3D tissue-engineered constructs poses challenges in conventional imaging techniques due to notable scattering and absorption effects in light microscopy, and hence limited penetration depth. We investigated contrast-enhanced micro-CT as a methodological approach for comprehensive morphological 3D-analysis of thein-vitromodel and compared the technique with confocal laser scanning microscopy, scanning electron microscopy and classical histology. Phosphotungstic acid and iodine-based contrast agents were employed for micro-CT imaging in laboratory and synchrotron micro-CT imaging. Results revealed spheroid shape variations and structural integrity influenced by cultivation methods and ACP particles. The study underscores the advantage of 3D spheroid models over traditional 2D cultures in mimicking bone tissue architecture and cellular interactions, emphasising the growing demand for novel imaging techniques to visualise 3D tissue-engineered models. Contrast-enhanced micro-CT emerges as a promising non-invasive imaging method for tissue-engineered constructs containing ACP particles, offering insights into sample morphology, enabling virtual histology before further analysis.

Rapid synthesis of cobalt manganese phosphate by microwave-assisted hydrothermal method and application as positrode material in supercapatteries

Electrochemical energy storage devices with high specific capacity are of utmost important for the next-generation electronic devices. Supercapatteries (SCs) are highly demanded energy storage devices nowadays as these bridge the low energy supercapacitors and low power batteries. Herein, we report a rapid synthesis of cobalt manganese phosphate (COMAP) by microwave-assisted hydrothermal method and facile fabrication of SCs using electrodes comprising of COMAP as positrode material. The effect of precursor concentration on the microstructure and surface morphology of the COMAP samples are examined initially. Further, the electrochemical performance of COMAP electrodes is studied systematically in 3 M KOH (aqueous) electrolyte. COMAP exhibits excellent charge storage capabilities where type of charge storage mechanism is found to be battery-type based on the calculation obtained from Dunn’s method. The SC electrode fabricated with COMAP synthesized using cobalt: manganese precursor ratio as 80:20 exhibits a highest specific capacity of 191.4 C/g at a scan rate of 1 mV/s. An asymmetric SC (ASC) cell fabricated with COMAP as positrode and activated carbon (AC) as negatrode exhibits a specific capacity of 165.5 C/g at a current density of 1.8 A/g. The COMAP//AC ASC cell exhibits an energy density of 34.1 Wh/kg at a corresponding power density of 1875 W/kg at a current density of 1.8 A/g.

High temperature thermoelectric properties of BaxSr2−xFeCoO6 double perovskites

Abstract In this study, environmentally benign BaxSr2-xFeCoO6 (BSFC) double perovskites are synthesized via solid-state reaction route for high-temperature thermoelectric applications. The crystal structure and morphology of the ceramic samples are analyzed using XRD and SEM, respectively. Rietveld refinement of XRD data confirms a cubic structure with Pm3̅m space-group. High-temperature thermoelectric measurements exhibits that substituting Ba for Sr in Sr2FeCoO6 increases the Seebeck coefficient (S) but at the expense of the electrical conductivity (σ). The highest Seebeck coefficient of 117 μV/K has been observed in Ba0.5Sr1.5FeCoO6 at 910 K. Temperature-dependent electrical conductivity measurements indicates a semiconductor-to-metal like transition in all samples, with BSFC (x = 0.1) achieving the highest conductivity of 4 × 104 S m−1 at ∼623 K. The thermoelectric power factor has been enhanced by over 50% with Ba substitution in Sr2FeCoO6. Electron transport in these double perovskites is found to follow the small polaron hopping conduction mechanism.

Plants-extracts mediated CuS nanoparticles: An effective antibacterial agent

Antibacterial activity of plant-mediated synthesized CuS nanoparticles against gram-positive Bacillus subtilis and gram negative Pseudomonas putida is studied in this presented work. A facile hydrothermal approach was followed to synthesize spherical shaped CuS nanoparticles using flowers extract of Tagetes patula (S1), leaves extract of Azadirachta indica (S2), and bark extract of Terminalia arjuna (S3). Crystal phase identification, average crystallites size, surface morphology, absorbance spectra and energy band gap analyses of samples were further determined using XRD, SEM, and UV-DRS spectroscopy respectively. Furthermore, under irradiation of visible light, antibacterial activity of marigold flowers mediated (S1), neem leaves mediated (S2), and arjuna bark mediated (S3) CuS samples were studied. XRD data confirmed the marigold mediated CuS sample has relatively smaller crystallites size of 10.67 nm. The estimated band gap energies for respective S1, S2, and S3 samples are 174 eV, 175 eV, and 177 eV. The antibacterial analysis of S1 sample displays its excellent antibacterial activity with the formation of relatively large inhibition zones of 29 mm and 30 mm diameters, against Bacillus subtilis and Pseudomonas putida respectively. The demonstrated antibacterial activity of biocompatible CuS nanoparticles suggests their potential use in biomedical applications.

Influence of Equal Channel Angular Pressing and Cyclic Extrusion Compression on the Microstructure Evolution and Mechanical Properties of Pure Aluminum.

The influence of equal channel angular pressing (ECAP) and cyclic extrusion compression (CEC) of Al-1080 on the pressing load, microstructure, and tensile properties was investigated. The pressing peak loads of the CEC were 218.8-265.4% higher than those of the ECAP, with a more complex load behavior in the CEC process. The deformation morphology of the ECAP samples indicates an improvement in the deformation homogeneity with the number of passes. Shear band morphology with a decrease in the shear band width from the center to the outer surface makes up the predominant pattern of the CEC samples. The ECAP samples have 13.9-44% smaller average grain sizes, with 3.8-8.1% higher high-angle grain boundaries (HAGBs) than the CECed samples. The ECAP and CEC processing improve the tensile strength. However, the ECAP sample's tensile strength (UTS) and the proof strength (σ0.2) were 11.5-20.6 and 2.6-16.4% higher than that of CEC, without noticeable differences in elongation. The σ0.2 values were predicted accurately with a deviation range of 1.8-7.3% from the experimental one. The ECAP samples are easy to process under lower loads. Moreover, ECAP samples have an equiaxed grain microstructure with a higher degree of deformation homogeneity and tensile strength.

In vitro assessment of corrosion, antibacterial properties, and degradation behavior of zirconia-coated polyetheretherketone (PEEK)

The medical industry often uses ceramic and polymeric coatings to safeguard metal substrates. However, more investigation is required to explore the implementation of ceramic coatings on polymer substrates and to determine their degradation and in vitro characteristics. This work involves applying zirconia coating onto the 3D-printed PEEK polymer substrate using the RF magnetron sputtering technique. With varying layer thickness and printing speed parameters, PEEK samples (S1, S2, S3, and S4) were 3D printed and coated with zirconia. The coated and uncoated samples were immersed in Fusayama artificial saliva solution for 30 days. Following immersion in artificial saliva, this study examined the corrosion of 3D-printed PEEK samples with and without coatings. Elemental mapping, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy were employed to evaluate sample morphology and estimate the binding energy of possible compounds generated in the artificial saliva solution. In vitro assessments such as antibacterial studies were performed against E. coli and S. aureus, and cytotoxic analysis was performed using Human Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) to determine cell proliferation. The results indicated that sample S3, printed with 0.15 mm layer thickness and 20 mm/s print speed coated with zirconia showed a better degradation rate of 9.01% whereas the other three samples S1, S2, and S4 coated with zirconia showed deterioration rates of 36.4%, 33% and 16% respectively. Sample S3 showed a better antibacterial activity as biofilm formation was absent and also showed cell viability of about 79% and hence can be considered as a viable option for dental applications.

Improving thermoelectric performance of Nickel substituted ZnSb alloy through carrier engineering and nanostructuring

Zn1-xNixSb (0 ≤ x ≤ 0.08) nanostructures were prepared by the planetary Ball milling technique. XRD analysis confirms the phase purity and orthorhombic crystal structure of the samples. FESEM analysis shows the spherical morphology of the Zn1-xNixSb samples. The EDX and elemental mapping analysis confirms the composition and elemental distribution of Zn1-xNixSb (0 ≤ x ≤ 0.08) alloys. HRTEM images clearly show the interfaced grains with grain boundaries. DRS-UV analysis revealed the narrowing of bandgap while increasing the Ni content in Zn site due to alloying effect. The synthesized Zn1-xNixSb alloys show low resistivity compared to pure samples due to high carrier concentrations. Seebeck coefficient of Zn1-xNixSb alloys were measured from room temperature to 635 K. A high-power factor of 1344 µW/m K2 was obtained for the Zn0.98Ni0.02Sb sample at 533 K compared to pristine ZnSb (574 µW/m K2 at 533 K). High thermoelectric figure of merit (zT) of 0.69 was achieved for Zn0.98Ni0.02Sb sample at 533 K compared to pristine ZnSb (zT of 0.34 at 533 K). The experimental results illustrated that Nickel substitution is a one of the possible ways to improve the thermoelectric figure of merit of ZnSb alloys.

Analysis of difficult flotation mechanisms for coarse low-rank coal: Comparing fluidized-bed and mechanical flotation technologies

Efficient flotation of coarse low-rank coal is essential for enhancing energy utilization in the mineral processing industry. As the beneficiation equipment scales up, the precision of particle size classification before flotation decreases, leading to a higher coarse particle content in the feed, which poses significant challenges to traditional flotation processes. Recent advancements in fluidized bed flotation technology have demonstrated considerable advantages in the flotation of coarse-grained metallic minerals; however, its application to coarse low-rank coal remains relatively unexplored. This study investigates the potential of fluidized bed flotation technology for coarse low-rank coal, employing various analytical methods to elucidate difficult flotation mechanisms. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were utilized to comprehensively characterize the surface morphology and chemical composition of coal samples. The influence of increasing particle size on flotation performance was systematically assessed through measurements of induction time and critical detachment amplitude. Comparative flotation experiments were conducted to evaluate the efficacy of traditional mechanical flotation against fluidized bed flotation technologies. Results indicate that the presence of cracks and oxygen-containing functional groups on the coal surface significantly enhances hydrophilicity, hindering flotation recovery rates. With increasing particle size, the induction time between particles and bubbles lengthens, while the critical detachment amplitude decreases, weakening the attachment and increasing detachment likelihood. Although high-efficiency collectors enhance coal particle hydrophobicity, they cannot fully mitigate the turbulence disrupting bubble-particle interactions in mechanical flotation. Conversely, fluidized bed flotation effectively minimizes turbulence interference, leading to an approximate 40 % increase in the recovery rate of coarse low-rank coal (0.25–1.00 mm) compared to traditional mechanical flotation. This study presents a novel technological approach for the efficient recovery of coarse low-rank coal, contributing to the clean utilization of low-rank coal resources.

In-situ monitoring of changes in temperature and microstrain during the chemical corrosion of stone cultural relics

Temperature changes during the chemical corrosion of stone cultural relics affect the condensation and evaporation of water and chemical reactions between soluble substances and corrosive solutions. This ultimately leads to changes in the internal structure and composition of the artifacts, which in turn lead to changes in the microstrain of cultural relics. To obtain in-situ real-time information on changes in the temperature and microstrain of stone cultural relics during chemical corrosion damage, a fiber Bragg grating (FBG) detection system was developed. The detection principle for the temperature and microstrain of sandstone was provided. Thermal field emission scanning electron microscopy, X-ray diffraction, and mercury intrusion porosimetry were used to characterize the surface morphology, composition, and pore structure of the sandstone samples, respectively. The temperature and microstrain changes of the sandstone samples under deionized water with different acidic/alkaline and salt solutions and at different temperatures were examined online in situ using the FBG measurement system. The results indicate that the dissolution of sandstone in the acidic solution (H2SO4 and NaHSO4) resulted in an exothermic chemical reaction as well as the dissolution of sandstone in the neutral salt solution (Na2SO4) and alkaline solution (NaOH and Na2CO3) led to material conversion and exothermic chemical reaction; the deionization reaction belongs to the dissolution reaction. The NaHSO4 solution caused the most serious corrosive disease on the sandstone surface. When the temperature of the NaHSO4 solution was 60 °C, the temperature and microstrain of the sandstone reached 63.9 °C and 253.6 με, respectively. The results of this study can support the research of revealing the corrosion mechanism of sandstone in different environments.

Tuning of Particle Size of Zeolitic Imidazolate Framework-7 via Rapid Synthesis Duration for CH4 Adsorption

In this work, zeolite imidazolate framework-7 (ZIF-7) nanoparticles are synthesized via a solvothermal method and rapid synthesis durations of 1 h and 3 h. The effect of the synthesis duration on the structural properties of ZIF-7 was characterized by XRD and FESEM analyses. Subsequently, CH4 single gas adsorption over ZIF-7 nanoparticles was examined using the volumetric method at room temperature and pressure ranging from 2 to 9 bar. The results showed that the synthesized ZIF-7 adsorbents were highly crystalline with a well-defined and homogeneous particle size distribution of 50–60 nm. It was found that increasing the synthesis duration from 1 h to 3 h did not amend the structure and morphology of the resultant samples significantly, mainly due to the short synthesis duration. Meanwhile, the CH4 adsorbed by ZIF-7 nanoparticles increased with rising pressure for both samples, and the ZIF-7 nanoparticles synthesized at 3 h showed a greater adsorption capacity than that of 1 h, mainly due to its higher crystallinity and well-developed pore structure. The ZIF-7 synthesized at 3 h demonstrated an adsorption capacity up to 2.2 mol/kg, which was higher than those values reported in the literature for micron-sized ZIF-7 samples. The CH4 gas adsorption behavior of ZIF-7 nanoparticles synthesized at 1 h and 3 h were well predicted by the Langmuir isotherm model, with coefficients of determination, R2, of 0.9994 and 0.9982, respectively.

Synthesis and Characterization of LaMnO3 Prepared by Hydrothermal Synthesis Method

Abstract LaMnO3 powders were prepared by hydrothermal synthesis method by varying citric acid to metal ions. The ratio of citric acid to metal ions is one of the parameters that have an affect on purity of LaMnO3 prepared by hydrothermal method. It is necessary to control the parameter to obtain the good quality of the final product of LaMnO3. LaMnO3 with variation molar ratio of citric acid to metal ion (CA/M) of 0, 1 and 4 were prepared. To determine the morphology, crystall structure, and phase composition, the powders were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD) techniques. The obtained results revealed that the morphology of sample CA/M = 0 has rod-like shape, CA/M = 1 was in the formed of irregular fine particles that stuck together and formed agglomerates, while the spherical morphology with various diameters were formed in the sample CA/M = 4. The XRD analysis demonstrated that sample CA/M = 1 had a single phase while in sample CA/M = 0 and CA/M = 4 others phase were detected such as La (OH)3 and La2O3. There was a change in crystall structure of the LaMnO3 phase in each sample due to the presence of citric acid. The peaks position in sample CA/M = 0, 1, dan 4 exhibit orthorhombic, rhombohendral and cubic structure with space group of Pnma, R -3c and Pm-3m respectively.

Exploring the photocatalytic activity of doped novel SrMoO4 nanoparticles in dye degradation: catalyzing change

To avert future energy crises, it is crucial to pursue sustainable energy sources nonstop. Due to its purity, sustainability, and dependability, solar energy stands out among the variety of evolving options. The utilization of solar energy for the generation of chemical energy has captured considerable attention, presenting the prospect of providing dependable and adaptable energy solutions. In this work, Sol-Gel method is used to synthesize extremely effective novel photocatalysts in the form of Strontium Molbydate (SM), 2.5 % Cerium doped Strontium Molbydate (SM2.5), and 5 % Cerium doped Strontium Molbydate (SM5) nanoparticles. The investigation includes a thorough examination of the photocatalytic study, structural analysis, and morphology of pure and doped samples. X-ray Diffraction (XRD) analysis of all the samples exhibit tetragonal structures, before and after degradation of dye. Scanning electron microscopy (SEM) was used to examine the morphology of each sample. To find out the functional groups present in the samples, Fourier Transform Infrared Spectroscopy (FT-IR) is employed. Liquid Chromatography Mass Spectrometry (LCMS) of the samples have also been done to find out the degradation product. The Mott-Schottky curves for SM, SM2.5, and SM5 exhibited positive slopes, indicating n-type semiconductor behavior. To determine the ecotoxicity of by-products of the CR ECOSAR program was operated. Ultraviolet visible spectroscopy (UV–Vis) results indicated the band gap for SM, SM2.5, and SM5 is 4.12 eV, 3.92 eV, and 3.74 eV, respectively. We employed the degradation of methylene blue (MB) in the presence of UV light irradiation to evaluate the photocatalytic activity. SM5 nanoparticles had the highest photocatalytic activity, reaching 95.5 % in 150 min. Pseudo second order kinetid model is best fitted, and the rate of reaction is 0.0021 (g mg⁻1 min⁻1), 0.0038 (g mg⁻1 min⁻1), 0.00413 (g mg⁻1 min⁻1) for SM, SM2.5, and SM5 respectively.

From mixed brookite/anatase TiO2 nanopowder to sodium titanates: Insight into morphology, structure, and photocatalytic performance

A method to obtain sodium titanate nanoribbons starting from a mixture of brookite and anatase TiO₂ nanopowder is described. As-prepared TiO2 nanopowder with a major brookite phase was used as a precursor in an alkaline hydrothermal approach, where the temperature was kept at 200 °C. The influence of hydrothermal treatment and consequent annealing temperature (T = 500 °C) on the crystal structure, phase composition, and morphology of samples were investigated by X-ray powder diffraction (XRPD), Raman and FTIR spectroscopy, and electron microscopy techniques (FESEM, HRTEM). All these methods point out that the hydrothermally treated sample, containing the NaTi3O6(OH)(H2O)2, Na2Ti3O7, and Na2Ti9O19, is dominated by layer-structured sodium hydroxititanate dihydrate. The annealing leads to the formation of rare sodium titanates, Na3Ti6O13 and Na2Ti9O19, with tunnel structures where the hexatitanate with increased sodium content prevails. The photocatalytic activity of synthesized nanostructures was tested in the degradation process of Reactive Orange (RO16) azo-dye upon UV excitation. It appears that photocatalytic activity is lower after hydrothermal treatment, but subsequent annealing makes sodium titanate nanoribbons faster in the degradation of RO16. The research implies that these sodium titanate nanostructures are promising photocatalytic materials and should be considered in the future for removing different pollutants from water.

Viability and antibacterial properties of Ba2-x AgxFeMoO6(x=0.0, 0.05) double perovskite oxides

Double perovskite Ba2FeMoO6 (BFMO) and doped with Ag ions were synthesized via the sol-gel method. The structural and antibacterial properties and viability of the samples were systematically investigated. The results of the Rietveld refinement indicated that both samples exhibited a single phase with cubic structure and space group Fm-3m. The substitution of Ag ions led to an increase in the unit cell and lattice parameters of BFMO, resulting in a change in the sample's morphology. The direct band gap (∼2eV) was measured for samples by Diffuse Reflectance Spectroscopy (DRS). Antibacterial activity of the Ba2FeMoO6 and Ba1.95Ag0.05FeMoO6 samples was assessed on the Gram-positive bacteria (Staphylococcus aureus) and the Gram-negative bacteria (Escherichia coli) using the spread plate method. The results showed that the samples were effective against Staphylococcus aureus but not against Escherichia coli. The sample doped with Ag ions showed a higher antibacterial effect than the pristine sample. An MTT assay of the normal fibroblast cell line treated with an Ag-doped sample showed a higher percentage of viability.

Impact of TBAI Doping on the Optical and Dielectric Features of PVC/MoO3/NiMoO4/PANI Polymer Composite for Optoelectronic and Energy Storage Applications

Poly (vinyl chloride, PVC)/MoO3/NiMoO4/polyaniline (PANI)/x wt% tetrabutylammonium iodide (TBAI) polymers were formed using casting and hydrothermal methods. The present study examined the nanocomposites’ structural, electrical, and optical features comprising PVC/MoO3/NiMoO4/PANI/x wt%TBAI polymers. X-ray diffraction and scanning electron microscopy were used to investigate the structure and morphology of different samples. The influence of different amounts of TBAI on the linear and nonlinear optical features of PVC/MoO3/NiMoO4/PANI/x wt%TBAI polymers was explored. Adding MoO3/NiMoO4/PANI.TBAI reduced the direct and indirect optical band gaps to their minimum values (3.88, 3.04) eV and (3.58, 2.13) eV, respectively. Doped polymer with MoO3/NiMoO4 has the highest refractive index value. Only PVC filled with MoO3/NiMoO4 exhibits the highest non-linear optical parameters within the visible range. The fluorescence intensity and emitted colors influenced by the kind of dopant. The dielectric constant and ac conductivity values of the host polymer were affected by the amount of TBAI. The maximum energy density value was observed in PVC/MoO3/NiMoO4/PANI/10 wt%TBAI polymer. The Cole-Cole plot demonstrated an irregular shift for doped samples relative to the undoped. The obtained results nominated the nanocomposite films of PVC/MoO3/NiMoO4/PANI/x wt%TBAI to be used in diverse electric and optoelectrical applications.

The synergistic effect of La dopant/willow catkins template on SnO2 monotubes for efficient detection of triethylamine

The detection of volatile organic compounds (VOCs) such as triethylamine (TEA) is essential for maintaining air quality and human health. This study explores the synergistic effects of lanthanum (La) doping and the use of willow catkins as a template for the performance of SnO₂ gas sensors for TEA detection. The morphology and structure of the as-synthesized samples were investigated, and a series of experiments were conducted to explore the TEA sensing characterization of SnO2-based sensors. The results of gas sensing demonstrated that the response of La2-SnO₂ sensors is up to about 178 at 100 ppm TEA, showing a 45 % increase compared to pure SnO₂ with a detection limit as low as 5 ppb. The fabricated sensors demonstrated a rapid response time of 60 s and a recovery time of 98 s at 100 ppm TEA concentration. Moreover, the sensors showed stable and repeatable responses over multiple cycles, indicating excellent reproducibility and long-term stability. The enhanced TEA sensing performance can be attributed to the abundant oxygen vacancies and promising tubular structure, which not only offer more active sites to absorb oxygen species but also promote the adsorption-desorption process of gas molecules. This study highlights the potential of La-doped SnO₂ sensors fabricated using a sustainable willow catkins template as a promising candidate for practical TEA detection applications.

Enhanced electrochemical performance of K0.67[Ni0.3Mn0.6Co0.1] O2 as a cathode material for secondary K-Ion batteries: Improved K-Ion insertion and reduced charge transfer barrier

Potassium-ion batteries, with their high operating voltage and cost-efficiency, emerged as promising contenders for large-scale energy storage system. Nevertheless, the practical application is hindered by the significant challenges of achieving high capacity and good rate capability in cathodes. Herein, a novel layered oxide cathode, K0.67[Ni0.3Mn0.6Co0.1] O2 (KNMCO), has been synthesized via solid-state (S-KNMCO) and co-precipitation (C-KNMCO) routes. The X-Ray diffraction (XRD) peaks of KNMCO are identified in R3 m space group and well-indexed to hexagonal unit cell. The FE-SEM shows non-spherical morphologies for both samples. Additionally, high-resolution transmission electron microscopy (HR-TEM) images of the synthesized cathode materials shows the interlayer spacing of S-KNMCO is higher than that of C-KNMCO. Furthermore, the electrochemical performance of S-KNMCO and C-KNMCO is characterized using K-metal as anode and electrolyte KPF6 in EC/DEC (1:1, v/v). The S-KNMCO and C-KNMCO exhibit the maximum specific discharge capacity of ∼101 mAhg-1 and ∼66 mAhg-1 at the current rate of C/20 respectively. Additionally, these cells show the good rate capability and coulombic efficiency (∼94%). This research offers novel perspectives on the development of cathode substances for KIBs.

Plasma assisted single-step synthesis of carbon-coated SrFe2O4 electrodes for enhancing supercapacitor and oxygen evolution reaction

Developing highly efficient, conductive, and porous electrode materials for superior electrochemical bifunctional applications presents a formidable challenge, particularly when considering impurity-free large-scale production. This investigation focuses on synthesizing a composite material of highly conductive amorphous carbon-coated SrFe2O4 nanoparticles to enhance supercapacitor and oxygen evolution performance. The C@SrFe2O4 nanoparticles were synthesized through a thermal plasma process utilizing argon, methane, and carbon dioxide gas environments. The prepared samples' phase, crystal structure, morphology, elemental composition, and chemical state analysis were thoroughly examined. The electrochemical performance of the prepared samples, including Fe3O4, SrO, and C@SrFe2O4 electrodes, was evaluated for their suitability in electrochemical capacitor applications. Remarkably, C@SrFe2O4 nanoparticles exhibited notable electrochemical pseudocapacitive behavior, demonstrating a significantly higher specific capacitance of 588.7 F/g at a current density of 1 A/g. Moreover, at a current density of 10 A/g, the C@SrFe2O4 electrode exhibited outstanding cycling stability, maintaining 91 % of its initial capacitance over 5000 charge-discharge cycles. Furthermore, it showcased exceptional and uniform electrocatalytic activity for the OER, requiring only 186 mV in overpotentials to achieve a current density of 10 mA/ cm2. These findings underscore the potential of mesoporous C@SrFe2O4 nanoparticles as promising materials for supercapacitors and OER applications.

Optical Limiting Methods by Z-Scan Technique for Non-Linear Optical Absorption of PVC/TiO2 Nanocomposite

To further our grasp of photonics technology, our work focuses on thin-film PVC/TiO2 nanocomposites. Nanocomposites composites were created by combining TiO2 nanoparticles with Polyvinyl Chloride (PVC) as the polymer matrix. The thin film was fabricated using the casting method. Spectral analysis was used to determine the absorbance parameters and compute the linear absorption coefficient. The nonlinear refractive index and nonlinear absorption coefficient were measured using a single beam Z-scan approach with a CW diode pumped solid state (DPSS) laser (Coherent Verdi-V5, 532 nm) acting as the excitation laser at 50mW. Peak absorption was measured at 280 nm, and as the percentage of TiO2 nanoparticles grew, more absorption was seen. The nonlinear absorption coefficient was determined to be 1x10−5 cm/W at (0.5342, 1.3585, 1.5999, and 0.0253). The poor structure arising from all of the sample morphologies affects the materials' NLO absorption. Nonetheless, they seem like good options for optical limiting applications given the positive value of NLO absorption.

Sulfate resistance of alkali-activated flyash-slag-lime concrete: comparative study of drying-wetting cycles and conventional exposure

Abstract Sulphate resistance of concrete is a crucial parameter for design of offshore structures. Of late alkali-activated materials are been given due consideration for infrastructure projects. In this context, the present study aims to assess the sulphate resistance of Alkali-Activated Concrete (AAC) with ternary blend of flyash-Ground Granulated Blast furnace Slag (GGBS) and limestone as the principal binder. The first phase of the study includes the optimization of ternary AAC mix with the inclusion of limestone as a potential binder to popularly used flyash slag blends. The inclusion of 5% limestone powder into the binder matrix is found to have beneficial effect on the mechanical properties of the ternary blended AAC. Further, an increase in the limestone powder content is not found to influence mechanical properties positively. The AAC mix with 5% limestone of total binder content was therefore selected for further evaluation of sulphate resistance. The sulfate resistance is evaluated under the alkaline media by subjecting AAC specimens to constant immersion and alternative drying and wetting cycles. The mechanical characteristics and mass reduction of the exposed samples were tested and compared with the conventional Ordinary Portland Cement (OPC) specimens. Evaluations were conducted over periods of 30, 45, 120, and 365 days of exposure. Scanning Electron Microscopy (SEM), and Energy Dispersion Spectroscopy (EDS) were also used to determine the surface morphology and mineral composition of samples after 365 days of exposure periods. The Flyash-Slag-Lime AAC exhibits denser morphology in comparison to OPC-based concrete, which in turn offers enhanced sulphate resistance.