AIBR Revista de Antropologia Iberoamericana

Abstract Traditional remediation strategies for soil contamination are inadequate due to various technical and economic gaps. Interest in nanomaterials (NMs), particularly two-dimensional (2D) NMs, is growing as these materials have become the essential components of different technologies, including energy storage, biosensors, and environmental remediation owing to large surface area, high surface functionalities, and outstanding electrical and thermal properties. The flourishing field of nanotechnology and NMs has attracted the attention of environmentalists and technologists for their integration into the field of soil remediation, as water remediation has already been studied to a larger extent. Therefore, this review has been designed to explore and analyse the role of graphene, its derivatives and their nanocomposites, one of the most emerging 2D materials in the field of environmental remediation, in mitigating soil contamination. The underlying mechanisms, namely, adsorption and catalytic degradation of the emerging soil pollutants, have been explored along with discussing the studies linked with the real-world implication of this technology. Further, the environmental and health impacts of graphene has also been highlighted, which is accumulated in the soil after reaction. Too optimise the soil remediation process by graphene and its derivatives, the challenges involved have also been discussed along with suggestive future strategies.

Abstract This study explores the magnetic properties of bilayer Penta-graphene-like nanostructures using Monte Carlo simulations, focusing on the effects of temperature, exchange interactions, crystal field anisotropy, and external magnetic fields. The analysis reveals how these factors govern magnetic phases, transitions, and overall stability. Furthermore, it examines spin alignment dynamics and phase boundaries, highlighting the potential of these nanostructures for advanced spintronic devices, high-density magnetic memory, and precision sensors, owing to their highly tunable magnetic responses.

In this study, a novel composite material combining Iron oxide and carbon quantum dots (CQDs, Fe3O4) with PANI was synthesized via a straightforward one-pot hydrothermal method, employing Iron sulfate, PANI and onion peels as the carbon source. The pursuit of an affordable, highly capable electrode material is useful for a variety of next-generation applications. The composite CQDs/PANI/Fe3O4 (PF-CDs) was analyzed using various techniques, including FTIR, XRD, SEM, TEM, and UV–vis spectroscopy. The analyses confirmed the presence of functional groups, crystalline structure of CQDs and Fe3O4 on the PANI surface, resulting in a well-formed nanocomposite with an average particle size of 25.6 nm. SEM images reveals that the rough surface of pure PANI becomes uniformly decorated with CQDs and Fe3O4 in the composite. FTIR study indicates that the core structures of CQDs and PANI are maintained in the nanocomposite. The cyclic voltammograms of the PF-CDs composite exhibit an increase in current density as scan rate increases with visible redox peaks around 0.5 V and 0.25 V. Appearance of semi-circle of the nanocomposite in the Nyquist plot further confirms that nanocomposite has minimum charge resistance and are capable of charge and discharge. Chrono charge discharge graph favours the redox cycle capability of the nanocomposite.

Using a conventional casting method, flexible polymeric film nanocomposites composed of PMMA (polymethyl methacrylate), PS (polystyrene), PVC (polyvinyl chloride) and ZnO nanoparticles were synthesized. Fourier transform infrared (FTIR) spectroscopy identified distinct peaks corresponding to vibrational groups in the prepared samples. Upon doping the PVC/PMMA/PS blend with varying concentrations of ZnO NPs (2.5–10 wt%), most absorption intensities tend to diminish progressively as the ZnO contents have been increased to 5 wt%. Changes in FTIR vibrational bands indicated interactions between the PVC/PMMA/PS/ZnO nanocomposite constituents. The XRD patterns of the ZnO NPs-based composites have exhibited the same peaks of the pure blend; however, there is a notable increase in broadness and a significant reduction in intensity as the weight percentage of ZnO NPs rises from 2.5 to 10. This observation indicates the development of interactions between the polymer and nanoparticles. The redshift seen in the absorption edge of the samples filled with ZnO provided strong evidence that charge transfer complexes had formed inside the polymeric matrix. The indirect and direct energy gaps for allowable transitions decreased with increasing ZnO NP concentrations, ranging from 3.88 eV and 4.87 eV in the pure blend to 3.31 eV and 4.67 eV, respectively. The σAC value at 100 Hz was 8.41 × 10−13 S·cm−1 and increased with frequency, reaching 5.12 × 10−9 S·cm−1 at 106 Hz. Also, a modest improvement in σ AC values is observed with the increase of ZnO NPs loading. The increase in conductivity can be ascribed to the improved amorphous nature of the synthesized nanocomposite facilitated by the incorporation of ZnO NPs. Dielectric studies showed that the best improvement was attained for the PVC/PMMA/PS/5 wt% of ZnO nanocomposite sample. Further, its imaginary part (ε″) exhibited a constructive decrease in its value with the increase in the ZnO loadings. These findings recommend these nanocomposites for potential applications in optoelectronics and energy storage devices.

Structure and morphology of PVA/PVP/SnS2/Fe-doped blends were considered employing X-ray diffraction and scanning electron microscopy. Maximum dielectric value was attained in the PVA/PVP/1 wt% SnS2/Fe blended polymers. Relaxation time was affected by the amount of filler. Energy density and AC conductivity were improved as the blend loaded with 5 wt% SnS2/Fe. Radiation parameters for all blends were explored using the Phy-X/PSD program. All blends exhibited relatively elevated MAC values at lower energy, specifically 15 keV. MAC diminished to 0.095 cm2/g for all blends when energy increased to 0.5 MeV. Doped blends had enhanced photon attenuation capacities. Doped samples exhibited superior attenuation properties. The doped blend with 10 wt% SnS2/Fe required the least thickness to attenuate photons at select energies relative to other blended polymers. At 0.5 MeV, the TF values were 89.33%, 89.03%, 89.83%, 88.02%, and 86.77% for samples with x values of 0, 1, 3, 5, and 10, respectively. At 5 cm thickness, TF % values were 56.88, 55.92, 58.50, 52.83, and 49.17 for samples with x values of 0, 1, 3, 5, and 10, respectively. At a distance of 1 cm, RPE values were 10.67%, 10.97%, 10.17%, 11.98%, and 13.23% for samples with x values of 0, 1, 3, 5, and 10, respectively. At 5 cm, RPE values rose to 43.12%, 44.08%, 41.49%, 47.17%, and 50.83% for the corresponding blends, respectively.

The hybrid halide perovskite CH3NH3PbI3-based humidity sensors demonstrate significant progress in detection range, response time, and durability. These improvements are attributed to the ionic conductivity of the material, tunable bandgap, and defect engineering. Simultaneously, their progress in energy conversion devices, such as solar cells, has achieved remarkable efficiency gains, exceeding 25%. The key challenges for commercializing these devices are moisture-induced degradation, lead toxicity, and scalability. Therefore, future research should prioritize stabilizing the material through novel encapsulation strategies, exploring lead-free alternatives, and developing multifunctional devices that synergistically exploit humidity sensitivity and energy conversion capabilities.

Abstract The diagnosis of brain tumors remains a challenging and resource-intensive task due to the complexity of brain tissue and the limitations of existing diagnostic tools. Biosensors operating in THz regime can be used to monitor changes in the characteristics of brain tissues, including refractive index, However, the technical drawbacks of such systems are high costs, long signal acquisition tim,e and the need for high-performance calculations. In this research, we proposed a Terahertz (THz) refractive index-based novel diamond hollow-core biosensor for examining various brain tissues. The biosensor has a sensitivity range of 1.30 to 1.40 RI and a figure of merit that falls between 51000 nm RIU⁻¹, allowing for precise and accurate real-time diagnosis. The second contribution involves applying advanced optimization approach to optimize the model parameters. With a sensitivity of 99.45%, specificity of 99.78%, precision of 99.51%, and total accuracy of 99.93% in identifying malignant brain tissues, performance analysis shows exceptional results.

Abstract This study focuses on the synthesis, characterization, and application of a novel polyvinyl chloride (PVC)/carbon nanotube (CNT)/zinc oxide (ZnO) hybrid nanocomposite. ZnO nanostructures with two distinct morphologies (nanohexagons and nanorods) were synthesized and embedded within a PVC matrix alongside CNTs to achieve a functional hybrid composite. TEM analysis revealed the presence of both nanohexagon and nanorod ZnO structures alongside CNTs. SEM and EDX analyses confirmed the uniform distribution of ZnO nanostructures and CNTs within the PVC matrix. FTIR and UV-vis analyses revealed successful integration of CNTs and ZnO, exhibiting well-defined morphologies with a high aspect ratio. The optical properties are characterized by a reduction in the optical bandgap from 5.40 eV for PVC/ZnO to 4.60 eV for PVC/ZnO/5%CNT, indicating an increase in absorption in the visible spectrum. Furthermore, the AC conductivity demonstrates significant frequency dependence, with conductivity increasing with CNT concentration due to the formation of conductive pathways. The dielectric constant also shows enhanced values with increased CNT content, attributed to improved interfacial polarization. The simulation of electric field distribution reveals that the PVC/CNT/ZnO nanocomposite exhibits a more uniform electric field distribution than conventional PVC. This study concludes that the PVC/CNT/ZnO nanocomposite has potential applications in optoelectronics devices.

Herein, the authors have explored the effect of incorporating TiO2 (0.01, 0.05, and 0.1 wt%) into the PMMA network. The crystal structure of the pure and doped PMMA displayed amorphous to crystalline shift with a 17 nm for TiO2 and 10 nm of PMMA/TiO2 with the highest wt%. Maximum reflectance scopes 62% for PMMA/TiO2 0.1 wt% at 456 nm. The reduced bandgap from 4.2 for PMMA to 3.3 eV for PMMA/TiO2 0.1 wt% potentilally by the emergence of energy levels. Fourier transform infrared spectroscopy demonstrated the resembling spectroscopy without shifts in representative peaks except for the increase in the peak cited at 450 cm−1, accredited to the Ti–O bond. The dielectric features verified the insertion of TiO2 into PMMA matrix triggered the permittivity improvement, offering interfaces for the charges accumulation. The Antimicrobial specifications of the PMMA and PMMA/ TiO2 were examined versus B. Subtilis, S. aureus, K. pneumoniae, E. coli, C. albicans, and A. niger. The advanced TiO2 wt% the larger antimicrobial activity, particularly regarding gram-negative bacteria. Highest activity demonstrated 67.42% versus K. pneumoniae for PMMA/TiO2 0.1 wt%, although the antifungal activity against C. albicans and A. niger was inconsequential.

GaFe1−xVxO3 samples (x = 0, 0.3) were manufactured through the solid-state reaction process. The phase singularity in each sample was tested using the search-match HighScore software. The structural/microstructural parameters of the samples were determined using the Fullprof program based on the Rietveld refinement methodology. The cation distribution across the four crystallographic sites in the GaFeO3 lattice was determined. The integration of vanadium into the lattice results in alterations in cation distribution, inducing distortions in the bond lengths and angles of tetrahedral and octahedral structures. In general, the distortions of octahedrons tend to increase with vanadium doping. The zero field cooling (ZFC) and field cooling (FC) with an applied magnetic field of 100 Oe were performed using a SQUID device. The magnetization field dependence (M-H) of both samples at 10 K was also measured. The Curie temperatures (T C) for both samples were determined. The magnetization of all samples demonstrates obvious hysteretic performance. The coercivity improved slightly from 1.55 kOe to 1.97 kOe, whereas the saturation and remanent magnetization reduced as GaFeO3 was doped with 30% vanadium. A minor rise in LAC and MAC was seen at low and high photon energy ranges, whereas a small reduction in both parameters took place in the medium photon energy range after GaFeO3 was doped with vanadium. Both HVL and TVL rose in the lesser and medium photon energy regions for vanadium-doped GaFeO3, but this trend is inverted at higher photon energy levels. Doped sample displays the lowest mean free path (MFP) values at elevated photon energy levels relative to the GaFeO3 sample. The effect of vanadium doping on the exposure build-up factor (EBF), energy absorption build-up factor (EABF), effective atomic number (Z eff), and equivalence atomic number (Z eq) parameters were also explored.

Abstract Modern society requires cutting-edge technologies built on renewable and sustainable energy sources to address the problems of environmental purification. In the present study, synthesis of pure and iron (Fe) doped zinc sulfide (ZnS) nanoparticles were carried out using co-precipitation technique. The prepared samples were characterized by x-ray diffraction (XRD) analysis, UV–visible spectroscopy, fourier transform infrared spectroscopy (FTIR), and photoluminescence spectroscopy (PL), to reveal the alterations in the structure and morphology of nanomaterials. XRD analysis showed the wurtzite phase of prepared nanoparticles. UV–visible spectroscopy reveals intensive absorption in the visible region upon Fe doping. The inclusion of Fe dopants into ZnS led to a decrease in the bandgap energy. FTIR spectra confirmed the presence of specific functional groups linked to the vibrational modes of samples. PL spectroscopy was used to study the transfer behavior of photo-generated electrons and holes in as prepared samples. The photoactivity and kinetics of photo-products were explored by monitoring photo-decolorization of methylene blue (MB) under solar irradiation. Photodecomposition of MB was dramatically increased when Fe-doped samples were employed relative to pristine ZnS. The present study suggests that Fe doped ZnS nanoparticles may be used as an efficient photocatalyst in wastewater treatment and associated environmental applications.

Abstract This study investigated the radiation shielding properties of gamma photons for lead and bismuth-modified borotellurite glasses at certain energy values in the 0.122–0.867 MeV range. The investigated glasses' mass attenuation coefficient (MAC) was evaluated, with the results revealing that the MAC of all the samples was the highest at 0.122 MeV. The glass sample with lowest percentage concentration of Bi2O3 and PbO2 has lower MAC than the other glasses. The glasses' linear attenuation coefficient varied in the 4.579–8.273 cm-1 range at 0.122 MeV, with the results emphasizing that Bi2O3 and PbO2 addition leads to an improvement in the glasses' radiation shielding effectiveness. Investigation of the glasses' half-value layer (HVL) found a decrease with increased density. The HVL varied between 1.92 and 2.49 cm at 0.779 MeV. A positive relation between the Bi2O3 and PbO2 amount and the glasses' attenuation performance was found through the effective atomic number (Zeff) results, with the highest Zeff recorded for the glass with 11 mol% of both Bi2O3 and PbO2. The transmission factor (TF) of the glasses was calculated, with the results demonstrating an improved attenuation ability with increased sample thickness, and as the Bi2O3 and PbO2 concentration increased, the TF values decreased.

Abstract As a third-generation semiconductor, silicon carbide (SiC) is extensively utilized in photovoltaic power generation, 5G communication, and new energy vehicles. However, the current method for the chemical mechanical polishing of SiC exhibits low material removal rates (MRRs) and suboptimal surface quality postpolishing. To address these challenges, we developed in this study a slurry that reduced the surface roughness of SiC–Si facets from 3.55 to 0.048 nm, achieving a MRR of 169 nm/h. The core removal mechanism involves a V2O3-catalyzed Fenton-like reaction to convert H2O2 into ·OH radicals for the rapid oxidation of the SiC–Si facets, which produces a softer oxide layer that is subsequently removed by the mechanical action of abrasives. Consequently, ultrasmooth SiC–Si facets with no visible scratches were obtained. On the basis of ultraviolet–visible spectral photoluminescence and X-ray photoelectron spectroscopy analyses, we propose a catalytic oxidation mechanism leading to high-quality surfaces on the SiC–Si facets. In addition, the identification of the active sites of the reaction by means of simulations further validates the polishing mechanism.

Abstract The detachment of charged, bumpy, and rough particles from rough surfaces in turbulent airflow in an electric field was studied. Electrostatic forces between the charged particles and the conductive surface were evaluated for various electric fields. Particles with corona ion charges, Boltzmann charge distribution, and saturation charges were considered. The enhanced JKR model was used to determine the adhesion force between micro-particle bumps and surfaces with fine roughness. Attention was given to particle rolling detachment in turbulent airflows when electrostatic forces contribute to the removal process. That is, the electrostatic Coulomb+ force points away from the surface, and hydrodynamic drag force and moment led to the rolling detachment of particles from the surface. The corresponding critical shear velocities for particle resuspension from a substrate were evaluated and compared against the experimental data. The effects of particle size, irregularity, and surface roughness for particle removal were studied. It was shown that appropriate electric fields could significantly reduce the shear velocity needed for particle removal. In fact, a sufficiently high electric field intensity could electrostatically remove the particle in the absence of airflow. Finally, the theoretical findings showed that the electrostatic effects could significantly improve the particle removal and surface cleaning processes.

Biomass-derived activated carbon has garnered significant attention due to its notable porosity, viability, and adequacy. This study employed peanut shells as the carbon source to produce porous carbon through hydrothermal carbonization (HTC) with or without activating reagents (Co and Zn Acetates) for evaluation as a supercapacitor electrode material. The dried precursor powder, with or without an activating agent, underwent hydrothermal treatment at 200 °C for 7 h, followed by carbonization at 400 °C for 3 h in an open atmosphere furnace. The sample treated with Zn acetate (PS-ZnA) exhibits the highest BET-specific surface area of 273.2 m2 g−1. Raman spectra depict distinct D and G bands at approximately 1343 and 1580 cm−1, respectively. The electrochemical performance was assessed using a three-electrode setup with 1 M H2SO4 electrolyte. The PS-ZnA demonstrates a specific capacitance of 105.5 F g−1, surpassing that of the PS-CoA. The PS-ZnA also exhibits energy and power densities of 8.62 Wh kg−1 and 381 W kg−1, respectively. Furthermore, the PS-ZnA illustrates an 88.2% retention rate after 5000 cycles at 10 A g−1, along with a low Rs value of 2.82 Ω, indicating favorable electrical conductivity. These findings strongly suggest that Zn acetate-treated porous carbon synthesized using HTC serves as an exceptional electrode material for supercapacitors.