Bulletin of Materials Science最新文献

Many companies that manufacture multilayer packaging frequently report failures in continuous inkjet (CIJ) coding, resulting in environmental and economic impacts. This study evaluated the parameters influencing the adhesion of three commonly used CIJ inks, considering the wettability, surface morphology, and chemical composition of the packaging surfaces. Three substrates were investigated: a poly(ethylene terephthalate) (PET) and polyethylene (PE) blend, both with and without corona treatment. The packaging materials were characterized by Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR–ATR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), contact angle measurements, and surface tension analysis. Ink adhesion was evaluated using the tape peel test in accordance with the FINAT FTM21 standard. The results indicate that PET exhibited favorable surface properties, including higher surface tension (37.4 dynes/cm) and a lower water contact angle (76.8°), resulting in adhesion grade 1 (no ink removal). In contrast, the PE blend showed only a slight increase in surface oxygen content after corona treatment (from 0.46 to 0.80 at%), a modest increase in surface tension (from 29.9 to 31.9 dynes/cm), and a small reduction in water contact angle (from 99.6° to 91.8°). These changes were insufficient to ensure effective ink anchoring, and PE blend samples, both treated and untreated, exhibited severe ink removal (>60%), corresponding to adhesion grade 5. This behavior may be associated with the inefficiency of the corona treatment process employed.

In the present study, we extensively studied the phonon and magnon excitations in nickel oxide (NiO) and Ni/NiO hybrid nanostructures using Raman scattering analyses. The NiO nanostructures were synthesized by facile hydrothermal route and annealed under air and argon (Ar) atmosphere at 800°C. Interestingly, Ar annealed NiO nanostructure shows fine sized particles and the formation of Ni/NiO hybrid. The morphological, structural and phonon vibrational modes of the synthesized nanostructures were investigated by transmission electron microscopy (TEM), grazing incident X-ray diffraction (GIXRD), and Raman scattering techniques. The TEM and GIXRD measurements confirm the formation of face centered cubic phase in NiO and Ni/NiO nanostructures. The surface optical phonon mode is observed in both NiO and Ni/NiO hybrid nanostructure and its theoretical peak positions are estimated using dielectric continuum model. Magnon modes do not appear in Ni/NiO nanostructure, which could be correlated to the reduction in the spin correlated length and super exchange interactions due to the symmetry breaking in the next nearest neighbor of Ni²⁺ ions in the linear atomic chain, Ni²⁺–O²⁻–Ni²⁺ of the crystal lattice.

The spread of COVID-19 led to a huge increase in the generation of polypropylene-based surgical face masks (SFMs) worldwide, leading to landfills and causing severe pollution of resources and the atmosphere when incinerated. In addition, the current treatment methods yield minimal carbon. Therefore, there is a growing need to upcycle waste SFMs into value-added products through safe and environmentally benign processes. In this study, waste SFMs were upcycled into activated carbon (AC) through a series of processes including sulfonation, pre-carbonization and activation with KOH at varying temperatures. The surface functionalities and textural properties of the resulting AC samples were thoroughly characterized using vibrational spectroscopy, N₂ sorption and microscopic studies. As the activation temperature increased, the porosity and surface area of the AC also increased. Notably, AC derived from SFMs upcycled at an activation temperature of 950°C (AC-950) exhibits an exceptionally high surface area of 2163 m² g⁻¹, promising oxygen reduction reaction (ORR) activity (high onset potential of 932 mV and limiting current density of 16.6 mA cm⁻²), comparable to the benchmark Pt/C electrocatalyst. In addition, it displays a commendable supercapacitor behaviour (specific capacitance of 236 F g⁻¹ at 1 A g⁻¹, good rate retention and cycle-life).

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This study presents an analysis of the Sprott (Phys. Lett. A 378 1361–1363, 2014) chaotic patterned electromagnetic absorber, which exhibits a broadband band absorption rate in the range of 2–20 GHz. The application studies commenced with an analysis of the parameters of the Sprott (2014) chaotic attractor, resulting in the generation of three-dimensional plane images. Given that the z-plane has a standard thickness of 0.035 mm in the electromagnetic absorber to be designed, the three-dimensional images obtained were processed with various iterations in the Julia fractal and transformed into two-dimensional patterns. These patterns were then examined in the simulation environment to assess the electromagnetic absorption of the patterns. In the design of the electromagnetic absorber, the chaotic patterns have been defined as copper with a standard thickness of 0.035 mm, and Magtrex 555, which exhibits frequency-dependent permeability, was selected as the substrate. In order to achieve the maximum absorption value, the back layer of the electromagnetic absorber structure was coated with copper sheet. This study examines the impact of the design parameters, including substrate thickness, absorber size, and substrate type, on the absorption rate of the electromagnetic absorber through a parametric analysis. The operational methodology of the proposed structure was elucidated through an examination of the electric field and surface current distributions at various resonant frequencies. The characteristics of the Sprott (2014) chaotic patterned electromagnetic absorber were subjected to a comprehensive analysis, which reveals its potential for integration into a multitude of contemporary applications. Notably, this study marks the inaugural application of the Sprott (2014) chaotic method in the design and optimization of a metamaterial absorber, thereby contributing a novel perspective to the existing literature on the subject.

The structure, electronic, magnetic and optical properties of pyrite CrO₂ at 46 GPa are extensively investigated for the first time using first-principles electronic structure calculations. Structural distortion is observed in the present material due to distortion in the CrO₆ octahedra. The system is found to be half-metallic and ferromagnetic. The two available electrons are found to be distributed among all five Cr-3d orbitals. The three Cr-t_2g (Cr-d_xy, d_yz, d_xz) as well as the two Cr-e_g (Cr-3d_3z²_{- r}², Cr-3d_x²_{- y}²) orbitals are observed to be degenerate. The partial filling and delocalization of electrons in all five Cr-3d orbitals for the majority spin channel are responsible for the half-metallic behaviour of pyrite CrO₂. The simultaneous effect of p-d hybridization and Cr–O antiferromagnetic coupling is responsible for ferromagnetism in the present material. The system remains half-metallic upon the application of U = 3 eV. The strength of ferromagnetism is enhanced at U = 3 eV. The Curie temperature T_c of pyrite CrO₂ is significantly reduced to 146 K (~156 K for U = 3 eV) at 46 GPa. The metallicity and anisotropy in the structure are observed in the investigation of the real [({upvarepsilon }_{1}left(upomega right))] and imaginary [({upvarepsilon }_{2}left(upomega right))] parts of the dielectric function. In the study of the energy loss function [(text{L}left(upomega right))], a significant electron energy loss is observed at a high pressure of 46 GPa. The system exhibits low dissipation or transparency up to 30 eV. The plasmon frequencies observed for ({text{L}}_{text{xx}}left(upomega right)), ({text{L}}_{text{yy}}left(upomega right)) and ({text{L}}_{text{zz}}left(upomega right)) (x-, y- and z-components of [(text{L}left(upomega right))]) are 26.72, 26.65 and 26.34 eV, respectively, below which the system remains metallic. It is observed that the optical properties do not change substantially upon applying U=3 eV.

This research explores the fabrication of tungsten trioxide (WO₃) nanocomposite thin films as an electron transport layer for photovoltaic solar cells. WO₃ was deposited on fluorine-doped tin oxide (FTO) glass using spin coating and aerosol-assisted chemical vapour deposition (AACVD) method to study the differences in structural, morphological, optical and electrical properties of the thin films. WO₃ nanocomposite thin films were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), ultraviolet–visible (UV–Vis) spectroscopy and linear sweep voltammetry (LSV). From XRD analysis, WO₃ thin films obtained from both methods showed a tetragonal anatase crystal phase with a h k l index of (2 2 1). FESEM images found that the particles in WO₃ thin films by the spin coating method were more even and uniformly distributed, while the film by the AACVD method had some agglomerations. From AFM, the surface of the WO₃ thin film prepared by the spin coating method was found to be smoother, whereas the thin film prepared by the AACVD method was rougher. UV–Vis spectroscopy analysis found that the bandgap energy of the thin film by the spin coating method is lower (2.40 eV) than which by the AACVD method (2.57 eV). From J–V characteristic analysis, it was found that the spin-coated WO₃ thin film has lower current density but higher power conversion efficiency (PCE; η = 0.278%), compared to the thin film by AACVD method, which has higher current density and lower PCE (η = 0.235%). This finding demonstrates the occurrence of a more efficient rate of charge movement between WO₃ layers through the spin coating method. Although it produces a lower photocurrent value, it enhances the efficiency of polymer solar cells.

The study of half-Heusler alloys has captured significant attention in materials science due to their unique electronic and mechanical properties. In this paper, we conducted an in-depth density functional theory (DFT) analysis to explore the half-metallic characteristics of the novel PdFeGa alloy, with particular focus on its band structure and elastic constants. As ternary compounds, half-Heusler alloys have attracted interest due to their versatile properties, which make them suitable for applications in thermoelectrics, spintronics and optoelectronics. Our theoretical investigation into the structural, mechanical, electronic, and magnetic properties of PdFeGa aims to identify stable half-metallic ferromagnets with Curie temperatures exceeding room temperature. PdFeGa exhibits half-metallic ferromagnetism, featuring a high magnetic moment localized at the Fe atom. The compound demonstrates a high Curie temperature and significant spin polarization. To ensure accuracy and convergence, calculations were conducted using the generalized gradient approximation (GGA) for the exchange-correlation potential, along with a dense k-point grid and high-energy cutoff. This DFT study confirms the half-metallic nature of PdFeGa, highlighting its promise for various technological applications.

The thermodynamic calculation was used in the Cd–Nd phase diagram according to the thermodynamic rule. Based on the newly reported phase relations, the thermodynamic expression of the four solution phases (liquid, bcc, dhcp and hcp_A3) was described with the Redlich–Kister form. Four species (Cd₁₁Nd, Cd₆Nd, Cd₅₈Nd₁₃ and Cd₃Nd) were treated as stoichiometric compounds. Three intallic compounds (α-Cd₂Nd, β-Cd₂Nd, CdNd and Cd₄₅Nd₁₁), which exhibited a little homogeneity range, were treated as a two-sublattice model (Model I). Three compounds (α-Cd₂Nd, β-Cd₂Nd, CdNd and Cd₄₅Nd₁₁), with low solubility, were used as a two-sublattice thermodynamic model (Model I). The compound CdNd was simultaneously optimized with another model to cope with disorderly transitions from bcc-A2 to bcc-B2 (Model II). The prescription of (Cd, Nd)_0.5(Cd, Nd)_0.5(Va)₃ was given expression to the order structure of the CdNd phase. Fourteen different types of phase transition were raised in the Cd–Nd system.

The slow hydrogen absorption kinetics, primarily caused by significant exothermic effects and resulting temperature variations, restrict the practical application of metal hydride. This study presents both experimental and numerical investigations of the Ti₂₄Zr₁₃Cr₂₅Mn₃₂Fe₆-based bed. The necessary kinetics and thermodynamic parameters for the simulation model were determined, showing a high degree of agreement between the experimental measurements and the fitted results. A cylindrical test reactor was also developed to evaluate the hydrogenation behaviours of the metal hydride bed under various operational conditions, using 9 Kg of powder in the larger reactor. The absorption and desorption processes of the AB₂-type metal hydride were simulated within this reactor. In order to improve heat dissipation and decrease experimental duration, internal square fins and heat exchange tubes (1/4′′, SS 316) were integrated into the reactor (outer diameter 76 mm, SS 316). The temperature evolution curves obtained experimentally were found to align closely with the simulation results, validating the numerical model’s accuracy and supporting the optimization of future metal hydride tank designs. This study offers valuable insights into the application of numerical simulations in advanced hydrogen storage systems.

Blue phase liquid crystals (BPLCs) possess remarkable optical properties, including selective visible light reflection, sub-millisecond response times and wide viewing angles without the need for alignment layers. These attributes make them highly promising for advanced display technologies. However, the narrow temperature range and high operating fields required for blue phase liquid crystal (BPLC) devices present significant challenges. Consequently, the integration of liquid crystals (LCs) with nanoparticles (NPs) to form BPLC composites has garnered considerable attention. This review summarizes experimental and synthetic methodologies, compares design strategies, and discusses both current cum potential applications of these composite materials.