Search Results (646)

Fe-CNT composites were synthesized via mechanical ball milling, incorporating varying amounts of carbon nanotubes (CNTs) into iron powder at concentrations of 1wt%, 2wt%, and 3wt%. The impact of different CNT contents on the phase structure, microstructure, and magnetic properties of the composites was examined. Raman spectroscopy and X-ray diffraction (XRD) analyses revealed that despite some damage, CNTs retained a predominantly one-dimensional nanostructure post-ball milling. Moreover, an increase in CNT content led to a gradual rise in grain size and lattice strain of the iron powder, attributed to the formation of solid solutions and iron–carbon compounds. Scanning electron microscopy (SEM) observations demonstrated that the majority of CNTs were integrated within the iron matrix particles, with a minority either partially embedded or entirely unembedded on the iron powder surface. With higher CNT concentrations, local CNT agglomeration emerged and intensified. Vibrating sample magnetometer (VSM) measurements indicated that Fe-CNT composites exhibited enhanced saturation magnetization (2.25%) and reduced coercivity (91.74%) compared to pure iron, underscoring the potential of CNTs in enhancing the magnetic properties of iron powder. Full article

This work thoroughly investigated the compound 4-(2,5-Dimethoxyphenyl)-3,4-dihydrobenzo[g]chromene-2,5,10-trione (DMDCT) using molecular docking, quantum chemical analysis, and vibrational spectroscopy methodology. The medicinal chemistry group has been particularly interested in chromene and benzochromene derivatives due to their wide range of pharmacological actions, including anticancer, antibacterial, anti-inflammatory, antioxidant, antiviral, and neuroprotective capabilities. In this connection, DMDCT has been explored to evaluate its biological, electrical, and structural properties. DFT using the B3LYP functional and 6–31G basis was established to conduct theoretical computations with the Gaussian 09 program. The findings from these computations provide insight into the following topics: NBO interactions, optimal molecular geometry, Mulliken charge distribution, frontier molecular orbitals, and MEP. Second-order perturbation theory has been used to assess stabilization energies arising from donor–acceptor interactions. Furthermore, general features such as chemical hardness, softness, and electronegativity were studied. The results suggest that DMDCT has stable electronic configurations and biologically relevant active sites. This integrated experimental and theoretical study supports the potential of DMDCT as a practical scaffold for future therapeutic applications and contributes valuable information regarding its vibrational and electronic behavior. Full article

The development of high-performance supercapacitor electrodes is crucial to meet the increasing demand for efficient and sustainable energy storage systems. Cobalt oxide (Co₃O₄), with its high theoretical capacitance, is a promising electrode material, but its practical application is hindered by poor conductivity limitations and structural instability during cycling. In this work, lanthanum La³⁺-doped Co₃O₄ nanocubes were synthesized via a hydrothermal approach to tailor their structural and electrochemical properties. Different doping concentrations (1, 3, and 5%) were introduced to investigate their influence systematically. X-ray diffraction confirmed the retention of the spinel phase with clear evidence of La³⁺ incorporation into the Co₃O₄ lattice. Also, Raman spectroscopy validated the structural integrity through characteristic Co-O vibrational modes. Scanning electron microscopy analysis revealed uniform cubic morphologies across all samples. The formation of the cubic spinel structure of 1% La³⁺-doped Co₃O₄ are confirmed from XPS and TEM studies. Electrochemical evaluation in a 3 M KOH electrolyte demonstrated that 1% La³⁺-doped Co₃O₄ nanocubes delivered the highest performance, achieving a specific capacitance of 1312 F g⁻¹ at 1 A g⁻¹ and maintaining a 79.8% capacitance retention and a 97.12% Coulombic efficiency over 10,000 cycles at 5 Ag⁻¹. It can be demonstrated that La³⁺ doping is an effective strategy to enhance the charge storage capability and cycling stability of Co₃O₄, offering valuable insights for the rational design of next-generation supercapacitor electrodes. Full article

Nanocrystals of Eu-doped GaN powders are produced via pyrolysis of a viscous compound made from europium and gallium nitrates. Furthermore, carbohydrazide is used as a fuel and toluene as a solvent; subsequently, a crucial nitridation process is carried out at 1000 °C for one hour. A slight shift of 0.04 degrees toward larger angles was observed for the X-ray diffraction patterns in the Eu-doped GaN powders regarding the undoped GaN powders, while Raman scattering also displayed a slight shift of 10.03 cm⁻¹ toward lower frequencies regarding the undoped GaN powders for the vibration mode, E₂(H), in both cases indicating the incorporation of europium atoms into the GaN crystal lattice. A scanning electron microscope micrograph demonstrated a surface morphology for the Eu-doped GaN with a shape similar to elongated platelets with a size of 3.77 µm in length. Energy-dispersive spectroscopy and X-ray photoelectron spectroscopy studies demonstrated the europium elemental contribution in the GaN. The X-ray photoelectron spectroscopy spectrum for gallium demonstrated the binding energies for Ga 2P_3/2, Ga 2P_1/2, and Eu 3d_5/2, which could indicate the incorporation of europium into the GaN and the bonding between gallium and europium atoms. The transmission electron microscope micrograph showed the presence of nanocrystals with an average size of 9.03 nm in length. The photoluminescence spectrum showed the main Eu³⁺ transition at 2.02 eV (611.69 nm) for europium emission energy, corresponding to the ⁵D₀ ⟶ ⁷F₂ transition of the f shell, which is known as a laser transition. Full article

This study reports on green-synthesized zinc oxide nanoparticles (ZnONPs), focusing on their physicochemical characterization, photocatalytic properties, and agricultural applications. Dynamic light scattering (DLS) analysis revealed a mean hydrodynamic diameter of 337.3 nm and a polydispersity index (PDI) of 0.400, indicating moderate polydispersity and nanoparticle aggregation, typical of biologically synthesized systems. High-resolution transmission electron microscopy (HR-TEM) showed predominantly spherical particles with an average diameter of ~28 nm, exhibiting slight agglomeration. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of zinc and oxygen, while X-ray diffraction (XRD) analysis identified a hexagonal wurtzite crystal structure with a dominant (002) plane and an average crystallite size of ~29 nm. Photoluminescence (PL) spectroscopy displayed a distinct near-band-edge emission at ~462 nm and a broad blue–green emission band (430–600 nm) with relatively low intensity. The ultraviolet–visible spectroscopy (UV–Vis) absorption spectrum of the synthesized ZnONPs exhibited a strong absorption peak at 372 nm, and the optical band gap was calculated as 2.67 eV using the Tauc method. Fourier-transform infrared spectroscopy (FTIR) analysis revealed both similarities and distinct differences to the pigeon extract, confirming the successful formation of nanoparticles. A prominent absorption band observed at 455 cm⁻¹ was assigned to Zn–O stretching vibrations. X-ray photoelectron spectroscopy (XPS) analysis showed that raw pigeon droppings contained no Zn signals, while their extract provided organic biomolecules for reduction and stabilization, and it confirmed Zn²⁺ species and Zn–O bonding in the synthesized ZnONPs. Photocatalytic degradation assays demonstrated the efficient removal of pollutants from sewage water, leading to significant reductions in total dissolved solids (TDS), chemical oxygen demand (COD), and total suspended solids (TSS). These results are consistent with reported values for ZnO-based photocatalytic systems, which achieve biochemical oxygen demand (BOD) levels below 2 mg/L and COD values around 11.8 mg/L. Subsequent reuse of treated water for irrigation yielded promising agronomic outcomes. Wheat and barley seeds exhibited 100% germination rates with ZnO NP-treated water, which were markedly higher than those obtained using chlorine-treated effluent (65–68%) and even the control (89–91%). After 21 days, root and shoot lengths under ZnO NP irrigation exceeded those of the control group by 30–50%, indicating enhanced seedling vigor. These findings demonstrate that biosynthesized ZnONPs represent a sustainable and multifunctional solution for wastewater remediation and agricultural enhancement, positioning them as a promising candidate for integration into green technologies that support sustainable urban development. Full article

Among the many nanomaterials studied for biomedical uses, silica and gold nanoparticles have gained significant attention because of their unique physical and chemical properties and their compatibility with living tissues. Mesoporous silica nanoparticles (MSNs) have great stability and a large surface area, while gold nanoparticles (AuNPs) display remarkable optical features. Both types of nanoparticles have been widely researched for their individual roles in drug delivery, imaging, biosensing, and therapy. When combined with gadolinium (Gd), a common contrast agent, these nanostructures provide improved imaging due to gadolinium’s strong paramagnetic properties. This study focuses on incorporating gold nanoparticles and gadolinium into a silica matrix to develop a theranostic system. Various analytical techniques were used to characterize the nanocomposites, including infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), nitrogen adsorption, scanning electron microscopy (SEM), dynamic light scattering (DLS), X-ray fluorescence (XRF), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), and neutron activation analysis (NAA). Techniques like XRF mapping, XANES, nitrogen adsorption, SEM, and VSM were crucial in confirming the presence of gadolinium and gold within the silica network. VSM and EPR analyses confirmed the attenuation of the saturation magnetization for all nanocomposites. This validates their potential for biomedical applications in diagnostics. Moreover, activating gold nanoparticles in a nuclear reactor generated a promising radioisotope for cancer treatment. These results indicate the potential of using a theranostic nanoplatform that employs mesoporous silica as a carrier, gold nanoparticles for radioisotopes, and gadolinium for imaging purposes. Full article

The fracture behavior of a locking pin used in the penultimate-stage blades of a 600 MW steam turbine in a thermal power plant was investigated through microstructural and microhardness characterization, fracture surface and energy-dispersive spectroscopy (EDS) analysis, as well as finite element load simulation. The microhardness values measured on the cross-section of the service pins ranged from 528 to 541 HV0.1, showing little difference from the unused pins. Scanning electron microscopy analysis revealed that approximately 70% of the fracture surfaces exhibited an intergranular “rock candy” morphology. The results indicate that pin failure was primarily caused by the combined effects of fretting wear and stress corrosion cracking (SCC). Specifically, vibration at the blade root, impeller, and pins due to start–stop cycles and load variations led to fretting wear, forming pits approximately 75 μm in size. Under the combined effects of weakly corrosive wet steam environments and shear stresses, SCC initiated at the high stress concentration points of these pits. Early crack propagation primarily followed original austenite grain boundaries, while later stages mainly extended along martensite plate boundaries. As cracks advanced, the cross-sectional area gradually decreased, causing the effective shear stress to increase until it exceeded the shear strength, ultimately leading to fracture. These findings not only provide a scientific basis for enhancing the reliability of steam turbine locking pins and extending their service life, but also contribute to a broader understanding of the failure mechanisms of key components operating under corrosive and fluctuating load environments. Full article

Microplastics (MPs) are increasingly recognized as widespread environmental contaminants, with confirmed presence in human tissues and biological fluids through ingestion, inhalation, and direct systemic exposure. Their potential impacts on human health have become an important subject of scientific investigation. The detection and quantification of MPs, particularly nanoplastics, in complex biological matrices remain challenging because of their low concentrations, diverse physicochemical properties, and interference from organic and inorganic matter. This review presents a critical assessment of current methods for the separation and detection of MPs from human-relevant samples. It examines pre-treatment, separation, and analytical approaches including physical filtration, density-based separation, chemical and enzymatic digestion, vibrational spectroscopy, thermal analysis, and electron microscopy, highlighting their principles, advantages, and limitations. Key challenges such as low sample throughput, absence of standardized procedures, and the difficulty of nanoplastic detection are identified as major barriers to accurate exposure assessment and risk evaluation. Recent advances, including functionalized adsorbents, improved anti-fouling membranes, integrated microfluidic systems, and artificial intelligence-assisted spectral analysis, are discussed for their potential to provide sensitive, scalable, and standardized analytical workflows. By integrating current challenges with recent innovations, this review aims to guide multidisciplinary research toward the development of reliable and reproducible detection strategies that can support MPs exposure assessment and inform evidence-based health policies. Full article

Understanding the interactions between carbon quantum dots (CDs) and promising food preservatives (FPs), like pyrogallol (PG), benzoic acid (BA), and gallic acid (GA), is highly relevant. This knowledge is crucial for designing CD-based sensors capable of determining the safe levels of these molecules in food and beverages. Additionally, such sensors could be exploited in the development of sustainable, intelligent packaging that controls food shelf life. Based on those considerations, in this study, we post-functionalized blue-emitting CDs, prepared according to a synthetic approach previously developed, with the FP molecules PG, BA, and GA to obtain CD-(FP) systems. UV-vis absorption and FTIR spectroscopy confirmed the presence of the FP molecules on the CD surface. The appearance of a new vibrational band at 1196 cm⁻¹ in the FTIR spectra of all CD-(FP) systems suggested that the three FP molecules interact with the CD surface via electronic interactions between the aromatic and delocalized electron systems. Further electrochemical analyses of the CD-(PG) and CD-(GA) systems show that the interactions between PG and GA benzene rings and CDs prevent their oxidation to the corresponding quinone forms. Full article

The citrate–nitrate method was employed to synthesize the magnesium chromite (MgCr₂O₄) spinel, followed by calcination at 700 °C for 3 h. The synthesized compound was analyzed using techniques including powder XRD, SEM-EDAX, FTIR, UV-DRS, and LCR Meter. The structural analysis was conducted using an X-ray diffractometer, which revealed the formation of the cubic crystal symmetry of the sample with the corresponding Fd-3 m space group. The average crystallite size of the sample was calculated around 15.38 nm. Using tetrahedral and octahedral positions, the lattice vibrations of the associated chemical bonds were identified using Fourier transform infrared (FTIR) spectroscopy. SEM (scanning electron microscopy) micrographs showed that the spherical nature of the particles and the constituent particles were between 10 and 40 nm in size. The optical bandgap value was evaluated using Tauc’s plot. Pellets of the powdered sample were prepared for determining the dielectric aspects, such as the dielectric constant (ε′) and tangent loss (tanδ), in the frequency range of 10 Hz–8 MHz at room temperature. The charge transport mechanism was explored from the complex impedance spectroscopy study. The obtained results indicate that magnesium chromite may be a potential candidate in the fabrication of sensors, micro-electronic devices, etc. Full article

This study reports the successful fabrication and characterization of two-dimensional (2D) vertical heterostructures composed of a semiconducting molybdenum disulfide (MoS₂) layer stacked with semimetallic platinum dichalcogenides (PtSe₂ and PtTe₂). The heterostructures were created using a versatile fabrication method that combines chemical vapor deposition (CVD) to grow high-quality MoS₂ nanolayers with thermally assisted conversion (TAC) for the synthesis of the Pt-based layers. The final MoS₂/PtSe₂ and MoS₂/PtTe₂ heterostructures were then assembled via a dry transfer process, ensuring high structural integrity. The quality and properties of these heterostructures were investigated using a range of advanced spectroscopic techniques. Raman spectroscopy confirmed the presence of characteristic vibrational modes for each material, validating successful formation. X-ray photoelectron spectroscopy (XPS) analysis further confirmed the elemental composition and oxidation states, though it also revealed the presence of elemental Pt⁰ and oxidized Te⁺⁴ in the PtTe₂ layer, suggesting an incomplete conversion. Importantly, the photoluminescence (PL) spectra showed a significant quenching effect, a clear sign of strong interlayer charge transfer, which is essential for optoelectronic applications. Finally, UV-Vis-NIR spectrophotometry demonstrated the combined optical properties of the stacked layers, with the Pt-based layers causing broadening and a blue-shift in the MoS₂ exciton peaks, indicating altered electronic and optical behavior. This research provides valuable insights into the synthesis and fundamental properties of MoS₂/PtX₂ heterostructures, highlighting their potential for next-generation electronic and optoelectronic devices. Full article

This study is focused on the hydrothermal synthesis of iron–manganese oxide nanostructures, focusing on the influence of Fe:Mn precursor ratios, temperature, and reaction time on phase formation, morphology, and structural characteristics. Three molar ratios (Fe:Mn = 2:1, 1:1, and 1:2) were explored under variable conditions (80 °C, 120 °C, and 200 °C; 4, 12, and 24 h). X-ray diffraction (XRD) analysis revealed distinct phase selectivity depending on precursor composition: FeMn₂O₄ was obtained with 1:2 ratio, Fe₃Mn₃O₈ with 1:1, and Fe₂MnO₄ with 2:1, each without phase mixing. Scanning electron microscopy (FESEM) showed a pronounced effect of temperature and time on nanoparticle morphology, ranging from compact agglomerates to well-defined rod-like structures at 200 °C/24 h. Dynamic light scattering (DLS) indicated narrow size distributions for samples synthesized at 120 °C/12 h, with hydrodynamic diameters between 20 and 50 nm. Raman spectroscopy confirmed the presence of characteristic vibrational modes of spinel-type structures and validated structural integrity. High-resolution transmission electron microscopy (HRTEM) evidenced well-ordered lattice fringes with interplanar spacings of ~0.48–0.52 nm, consistent with spinel phases and indicative of high crystallinity. These findings demonstrate that controlled atomic binding and thermal parameters enable selective synthesis of pure iron–manganese oxide phases with tailored morphologies, offering a scalable route for designing advanced functional materials in catalysis, energy, and biomedical applications. Full article

In this study, we report the fabrication and multi-technique characterization of pure and rare-earth (RE)-doped ZnO thin films using nanostructured microclusters synthesized via electrospinning followed by calcination. Lanthanum (La), erbium (Er), and samarium (Sm) were each incorporated at five concentrations (0.1–5 at.%) into ZnO, and the resulting powders were drop-cast as thin films on glass substrates. This approach enables the transfer of pre-engineered nanoscale morphologies into the final thin-film architecture. The morphological analysis by scanning electron microscopy (SEM) revealed a predominance of spherical nanoparticles and nanorods, with distinct variations in size and aspect ratio depending on dopant type and concentration. X-ray diffraction (XRD) and Rietveld analysis confirmed the wurtzite ZnO structure with increasing evidence of secondary phase formation at high dopant levels (e.g., Er₂O₃, Sm₂O₃, and La(OH)₃). Raman spectroscopy showed peak shifts, broadening, and defect-related vibrational modes induced by RE incorporation, in agreement with the lattice strain and crystallinity variations observed in XRD. Elemental mapping (EDX) confirmed uniform dopant distribution. Optical transmittance exceeded 70% for all films, with Tauc analysis revealing slight bandgap narrowing (Eg = 2.93–2.97 eV) compared to pure ZnO. This study demonstrates that rare-earth doping via electrospun nanocluster precursors is a viable route to engineer ZnO thin films with tunable structural and optical properties. Despite current limitations in film-substrate adhesion, the method offers a promising pathway for future transparent optoelectronic, sensing, or UV detection applications, where further interface engineering could unlock their full potential. Full article

This study investigates the effects of different tungsten (W) doping contents on the optical transmittance, surface roughness, residual stress, and microstructure of evaporated vanadium dioxide (VO₂) thin films. W-doped VO₂ thin films with varying tungsten concentrations were fabricated using electron beam evaporation combined with ion-assisted deposition techniques, and deposited on silicon wafers and glass substrates. The optical transmittances of undoped and W-doped VO₂ thin films were measured by UV/VIS/NIR spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The root mean square surface roughness was measured using a Linnik microscopic interferometer. The residual stress in various W-doped VO₂ films was evaluated using a modified Twyman–Green interferometer. The surface morphological and structural characterization of the W-doped VO₂ thin films were performed by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). Raman spectroscopy was used to analyze the structure and vibrational modes of different W-doped VO₂ thin films. These results show that the addition of tungsten significantly alters the structural, optical, and mechanical properties of VO₂ thin films. Full article

This study employs molecular orbital (MO) analysis, density of states (DOS) analysis, and advanced techniques such as charge density difference (CDD), transition density matrix (TDM), transition electric dipole moment density (TEDM), and transition magnetic dipole moment density (TMDM) to systematically investigate the electronic structure characteristics of Fc-[8]CPP and Fc-[11]CPP. Using density functional theory (DFT) and time-dependent DFT (TD-DFT), the π-electron delocalization properties and optical behaviors of these molecules were analyzed. Furthermore, their responses to external electromagnetic fields were explored through electronic circular dichroism (ECD) and Raman spectroscopy, comparing chiral optical responses and electron–vibration coupling effects to elucidate their photophysical properties. The results reveal that the HOMO-LUMO energy gaps of Fc-[8]CPP and Fc-[11]CPP are 5.81 eV and 5.95 eV, respectively, with a slight increase as ring size grows; Fc-[8]CPP exhibits a stronger chiral response, while Fc-[11]CPP shows reduced chirality due to enhanced symmetry. Finally, TD-DFT calculations demonstrate that their optical absorption is dominated by localized excitations with partial charge transfer contributions. These findings provide a theoretical foundation for designing conjugated macrocyclic materials with superior optoelectronic performance. Full article