Search Results (10,254)

The aim of the present research is to validate the combined use, through data fusion, of a Laser Induced Fluorescence (LIF) scanning system and a radar scanner (RGB-ITR, Red Green Blue Imaging Topological Radar system), as a unique tool to address the need for non-invasive, rapid, and low-cost techniques for both diagnostic and operational needs. The integrated system has been applied to the House of Diana complex in Ostia Antica. The main diagnostic objective of this research was to trace the materials used in different phases of restoration, from antiquity to modernity, on both masonry and pictorial surfaces, to reconstruct the history of the building. Due to the significant interest in this insula, other studies have been recently carried out on the House of Diana, but they once again highlighted the necessity of multiple approaches and non-invasive methods capable of providing quasi-real-time answers, delivering point-by-point information on very large surfaces to overcome the limits related to representativeness of sampling. The data acquired by the RGB-ITR system are quantitative, allowing for morphological and 3-colour analysis of the investigated artwork. In this work, the sensor has been used to create coloured 3D models useful for structural assessments and for locating different classes of materials. In fact, the LIF maps, which integrate knowledge about the original constituent materials and previous conservation interventions, have been used as additional layers of the tridimensional models. Therefore, the method can direct possible new investigations and restoration actions, piecing together the history of the House of Diana to build for it a safer future. Full article

Silk fibroin (SF)-based materials attract significant interest because of their biocompability and great diversity of possible morphologies. One of the approaches to obtain SF materials is the use of an air–water or oil–water interface as a template for protein self-assembly. Surfactants can change the surface properties of adsorbed SF layers by promoting or preventing the formation of SF fiber networks. This study focuses on the influence of two typical ionic surfactants, cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium dodecyl sulfate (SDS), on the dynamic properties of SF layers adsorbed at the air–water interface. The dynamic surface elasticity, surface tension, ellipsometric angle Δ, and the film thickness were measured as a function of the surface age and surfactant concentration. The morphology of the layers was evaluated by atomic force microscopy (AFM). For the adsorption layers of globular proteins, the main effect of the surfactants consists in the protein unfolding at high concentrations and in a decrease in the electrostatic adsorption barrier. In the case of SF layers, CTAB and SDS strongly influence the protein aggregation at the air–water interface. Regardless of the sign of the surfactant charge, its addition to SF solutions results in a decrease in the surface elasticity and the destruction of the ordered structure of protein fibers at concentrations higher than 1 × 10⁻⁴ M. With the further increase in the surfactant concentration, the thread-like aggregates disappear, the packing of thin fibers becomes less tight, a uniform layer disintegrates into separate islands, and finally, the protein is displaced from the interface. Full article

Peptide-based biomimetic treatments have gained increased attention in the dental field due to their biocompatibility and minimally invasive qualities. These biomimetic approaches can replicate the native architecture of dental tissues, thus contributing to higher success rates and improved longevity of restorations. The aim of this study was first to examine the biocompatibility and stability of an amelogenin peptide-based chitosan hydrogel (P26-CS) against salivary enzymes. Second, we aimed to evaluate its efficacy in biomimetically repairing human dental lesions in situ. White spot lesions (WSLs) in enamel and non-carious cervical lesions (NCCLs) in dentin were artificially created. Chitosan (CS) improved peptide stability, while remineralization of enamel sections with P26-CS was not impeded by salivary enzymes. The peptide was not cytotoxic, irritating, or sensitizing. Fluorescently labeled P26-CS penetrated ~300 μm into the enamel of WSLs and ~100 μm into the dentin of NCCLs. After peptide treatment, quantitative light-induced fluorescence (QLF) and microcomputed tomography (μCT) indicated a gain in mineral density of WSLs. In NCCLs, scanning electron microscopy showed that the dentin was covered by a mineral layer of needle-shaped crystals. Our results show that the repair of artificial WSLs and NCCLs was achieved by P26 peptide-guided remineralization and demonstrate its potential to repair dental lesions. Full article

In this paper, we consider the issue of the physical layer security (PLS) problem between two nodes, i.e., transmitter (Alice) and receiver (Bob), in the presence of an eavesdropper (Eve) in a near-field communication (NFC) system. Notably, massive multiple-input multiple-output (MIMO) arrays significantly increase array aperture, thereby rendering the eavesdroppers more inclined to lurk near the transmission end. This situation necessitates using near-field channel models to more accurately describe channel characteristics. We consider two schemes with imperfect channel estimation information (CSI). The first scheme involves a conventional multiple-input multiple-output multiple-antenna eavesdropper (MIMOME) setup, where Alice simultaneously transmits information signal and artificial noise (AN). In the second scheme, Bob operates in a full-duplex (FD) mode, with Alice transmitting information signal while Bob emits AN. We then jointly design beamforming and AN vectors to degrade the reception signal quality at Eve, based on the signal-to-interference-plus-noise ratio (SINR) of each node. To tackle the power minimization problem, we propose an iterative algorithm that includes an additional constraint to ensure adherence to specified quality-of-service (QoS) metrics. Additionally, we decompose the robust optimization problem of the two schemes into two sub-problems, with one that can be solved using generalized Rayleigh quotient methods and the other that can be addressed through semi-definite programming (SDP). Finally, our simulation results confirm the viability of the proposed approach and demonstrate the effectiveness of the protection zone for NFC systems operating with CSI. Full article

The purpose of this study was to explore multiple facets of young adolescent identity and related experiences through a scoping literature review. Based on Gardenswartz and Rowe’s Four Layers of Diversity Model, we specifically examined extant literature around five of the internal dimensions: gender, sexuality, race, ethnicity, and physical ability. Two overarching research questions guided this investigation: What is the range and nature of current findings on young adolescent identity and experience? What gaps exist in research on young adolescent identity and experiences? To address these research questions, our research group conducted a scoping literature review using predetermined search strings related to young adolescents, identity, and experiences. We organized and presented our results in three sections: (a) gender and sexuality, (b) race and ethnicity, and (c) physical ability and disability. For each section, we specified the relevant research details, summarized the nature and characteristics of articles reviewed in a table, and described the themes derived from the reviews of literature. An overall finding was the dearth of research on young adolescent identity and experiences. Our research highlights the importance of an intersectional approach for understanding and studying the totality of young adolescent identity and experiences. Full article

Lip augmentation has become increasingly popular in aesthetic medicine, driven by advancements in dermal filler technologies and injection techniques. This review provides a comprehensive overview of lip anatomy, age-related changes, and current best practices in lip augmentation using dermal fillers. The complex structure of the lips, including multiple layers of skin, muscle, and mucosa, contributes to their unique appearance and function. Age-related changes, such as volume loss, thinning of the vermilion border, and flattening of the philtrum, significantly impact lip aesthetics. Understanding these changes is crucial for developing effective treatment strategies. The review discusses the importance of tailoring treatments to individual patient needs, considering factors such as ethnic variations in lip structure and cultural preferences. It emphasizes the significance of proper filler selection, with hyaluronic acid-based products being the gold standard due to their biocompatibility and reversibility. Injection techniques, including needle and cannula approaches, are described in detail, with a focus on safety and optimal aesthetic outcomes. Anatomical considerations, particularly the vascular supply to the lips, are highlighted as critical for avoiding complications during filler injections. The review also addresses the evolving approach to lip augmentation, which now focuses on restoring natural contours and addressing age-related changes in the perioral region rather than simply increasing volume. Finally, the importance of managing patient expectations and the potential for future advancements in the field are discussed, including the development of more targeted filler products and refined injection techniques. Full article

The aquatic plant species Eichhornia crassipes, commonly known as water hyacinth, is indigenous to South America and is considered an invasive species. The invasive water hyacinth has caused significant economic and ecological damage by preventing sunlight from penetrating the surface of the water, resulting in the loss of aquatic life. To quantify the invasiveness and address the issue of accurately identifying plant species, water hyacinths have prompted numerous researchers to propose approaches to detect regions occupied by water hyacinths. One such solution involves the utilization of multispectral imaging which obtain detailed information about plant species based on the surface reflectance index. This is achieved by analyzing the intensity of light spectra at different wavelengths emitted by each plant. However, the use of multispectral imagery presents a potential challenge since there are various spectral indices that can be used to capture different information. Despite the high accuracy of these multispectral images, there remains a possibility that plants similar to water hyacinths may be misclassified if the right spectral index is not chosen. Considering this challenge, the objective of this research is to develop a low-cost multispectral camera capable of capturing multispectral images. The camera will be equipped with two infrared light spectrum filters with wavelengths of 720 and 850 nanometers, respectively, as well as red, blue, and green light spectrum filters. Additionally, the implementation of the U-Net architecture is proposed for semantic segmentation to accurately identify water hyacinths, as well as other classes such as lakes and land. An accuracy rate of 96% was obtained for the identification of water hyacinths using data captured by an autonomous drone constructed in the laboratory flying at an altitude of 10 m. We also analyzed the contribution each of the infrared layers to the camera’s spectrum setup. Full article

In geotechnical earthquake engineering, enhancing the seismic properties of foundation soil to modify the characteristics of earthquake waves transmitted to structures presents a viable solution. This study investigates the effect of placing an isolation layer, composed of a mixture of recycled tire rubber and sand, beneath structures to mitigate seismic forces acting on buildings situated on soil layers with high amplification potential. In other words, the role of a soil layer functioning as a seismic isolator is examined. To achieve this objective, the seismic behavior of building-type structures is analyzed through numerical simulations, supplemented by laboratory experiments available in the literature. The numerical analyses are performed in the frequency domain using the finite element method within a one-dimensional (1D) framework. To validate the feasibility of the proposed isolation layer based on parametric analysis results, comparisons are made with laboratory tests available. In the literature, seismic isolation applications with thicknesses ranging from 1 to 3 m resulted in reductions of 6.8% to 16.17% in response spectral accelerations measured at the surface, while improvements in Fourier amplitude ratios ranged between 12.03% and 13.98%. This approach aims to provide an economical and efficient solution for earthquake-resistant structures while simultaneously promoting sustainability by recycling waste tires, contributing both to environmental conservation and economic benefits. Full article

Powering wearable and portable devices, triboelectric nanogenerators (TENGs) are a considerably promising technology. Low-cost production, ease of fabrication, optimal efficiency, and high output performance are always key concerns in developing energy harvesting technologies. Optimum efficiency and high output are always key concerns. This research addresses the ongoing challenge of raising efficient, flexible, and lightweight energy harvesting systems for recent wearable technologies. In this research, a triboelectric nanogenerator is proposed for harvesting the triboelectric effect. Using polyurethane (PU), a bendable TENG that is in the vertical contact separation mode was developed. UV-curable PU forms the basis of TENGs. A sponge, repurposed from landfill waste, acts by means of a spacer to maintain a consistent air gap between the tribo-layers for enhanced triboelectrification. The triboelectric nanogenerators formed a V_oc approaching 500 V and a current of ~2 µA and also showed high performance with a power density of 8.53 W/m². In addition, the triboelectric nanogenerator can light LEDs and charge capacitors, making it a self-powered energy source for portable devices, Wi-Fi, and monitoring systems. The proposed TENG provides a capable solution for sustainable, self-powered wearable electronics and has the potential for further development in energy-efficient and eco-friendly applications. Full article

The Arabian–Nubian Shield (ANS) hosts numerous volcanogenic massive sulphide (VMS) deposits formed in submarine volcanic settings and enriched by hydrothermal processes, making it a critical region for mineral exploration due to the types of deposits it hosts and its geological complexity. The Wadi Bidah Mineral Belt (WBMB), located within the Arabian Shield, contains over 30 polymetallic VMS occurrences associated with an island arc system active between 950 and 800 million years ago. Despite its mineral potential, the WBMB still needs to be explored, with limited geophysical studies to support resource evaluation. This study focuses on the Hawiah area, a prominent VMS site within the WBMB, to delineate subsurface mineralization using transient electromagnetic (TEM) methods. TEM surveys were conducted to characterize the conductivity structure and identify potential zones of sulphide mineralization. Data were processed and inverted to generate 1D, 2D, and 3D resistivity models, providing critical insights into the depth, geometry, and continuity of the mineralized zones based on the final 3D resistivity distribution. The results revealed distinct conductive (very low resistivity) anomalies, correlating with known surface gossans and inferred sulphide-rich layers, and extended these features into the subsurface. The integration of TEM results with geological and geochemical data highlights the effectiveness of this approach in detecting and mapping concealed mineral deposits in complex geological environments. This study advances the understanding of VMS systems in the WBMB and demonstrates the potential of TEM surveys as a key tool for mineral exploration in the Arabian Shield. Full article

The arrival of nanotechnology in the field of metal castings is considered a promising approach to significantly improve the quality, performance and lifetime of castings. A better understanding of the implementation of nanotechnology in the metal casting process and its dynamics is essential for the successful production of metal matrix nanocomposite castings. This review focuses on past and present techniques for metal matrix nanocomposite castings to facilitate future fabrication processes and improve the performance of casting products. The advantages, limitations, difficulties and optimal processing conditions of nanocomposite castings are presented and thoroughly discussed. Both types of metal matrix nanocomposites (i.e., ferrous and nonferrous metallic matrices, are discussed in the present review), as well as nanocomposites in the working surface layer and interlayer of bimetallic materials. Significant improvements in the surface microstructure and shear strength of bimetallic bearings are achieved using nanoparticles as additions to the surface working layer and interlayer areas. Special emphasis is given to the factors affecting these fabrication processes in achieving high-quality products. The dispersion of nanoparticles in the metallic matrix is another critical issue, which is discussed comprehensively. Moreover, the strengthening mechanisms that evolve due to the incorporation of nanoparticles in the metallic matrices, which deserve separate attention, are discussed. The economic and political factors that simultaneously lead to evolutionary and drastic changes in metal matrix nanocomposite castings are also considered. Finally, the present article indicates future fabrication routes and describes the development of metal matrix nanocomposite castings under the influence of nanotechnology after incorporating the novel casting opportunities presented by nanotechnology. Full article

Multi-layer films are one of the most challenging classes of polymer waste for recycling, as they consist of a mixture of constituent materials like polyethylene (PE), polyamide 6 (PA6), and ethylene vinyl alcohol (EVOH). This study investigates the characterization, washing, and mechanical properties of recycled blends derived from such multi-layer films. Raman spectroscopy and Differential Scanning Calorimetry (DSC) were used to characterize the individual components in single- and multi-layer films, and distinct properties of LDPE, LLDPE, PA6, and EVOH were observed. Mechanical properties enhanced by proper shredding, washing procedures, and multiple combinations of polyethylene blends were investigated to optimize the mechanical characteristics of the recycled materials, especially strain at break. Additionally, the shrinkage behavior of the recycled films was compared to commercial shrink films, demonstrating their potential for use in industry packaging applications. These results highlight a more sustainable possibility for multi-layer packaging applications. Full article

The green transition trend in the wood-based panel industry aims to reduce environmental impact and waste production, and it is a viable approach to meet the increasing global demand for wood and wood-based materials as roundwood availability decreases, necessitating the development of composite products as alternatives to non-wood lignocellulosic raw materials. As a result, the purpose of this study is to examine and assess the physical, mechanical, and acoustic properties of particleboard manufactured from non-wood lignocellulosic biomass. The core layer was composed of non-wood lignocelluloses (banana stem, rice straw, coconut fiber, sugarcane bagasse, and fibrous vascular bundles (FVB) from snakefruit fronds), whereas the surface was made of belangke bamboo (Gigantochloa pruriens) and wood. The chemical characteristics, fiber dimensions and derivatives, and contact angles of non-wood lignocellulosic materials were investigated. The contact angle, which ranged from 44.57 to 62.37 degrees, was measured to determine the wettability of these materials toward adhesives. Hybrid particleboard (HPb) or sandwich particleboard (SPb) samples of 25 cm × 25 cm with a target density of 0.75 g/cm³ and a thickness of 1 cm were manufactured using 7% isocyanate adhesive (based on raw material oven dry weight). The physical parameters of the particleboard, including density, water content, water absorption (WA), and thickness swelling (TS), ranged from 0.47 to 0.79 g/cm³, 6.57 to 13.78%, 16.46 to 103.51%, and 3.38 to 39.91%, respectively. Furthermore, the mechanical properties of the particleboard, including the modulus of elasticity (MOE), bending strength (MOR), and internal bond strength (IB), varied from 0.39 to 7.34 GPa, 6.52 to 87.79 MPa, and 0.03 to 0.69 MPa, respectively. On the basis of these findings, the use of non-wood lignocellulosic raw materials represents a viable alternative for the production of high-performance particleboard. Full article

A simple and robust two-dimensional chromatographic fractionation protocol for the isolation of the neuroprotective compound erinacine A from Hericium erinaceus is proposed. This production platform yielded 19.4 mg of erinacine A from approximately 130 g of mushroom material, with a chromatographic purity of 97.4%. The procedure includes extraction, concentration, fractionation, purification, and characterisation of the bioactive compound. The crude H. erinaceus extract was fractionated in the first dimension by normal-phase flash chromatography, and the fraction containing erinacine A was further purified in the second dimension by semi-preparative reversed-phase chromatography. This strategy utilises the orthogonality of the two chromatographic modes to effectively eliminate difficult impurities, including structural isomers and analogues of erinacine A. Complementary analytical approaches such as high-performance thin-layer chromatography (HPTLC) and high-performance liquid chromatography with ultraviolet and tandem mass spectrometric detection (HPLC–UV–MS/MS) were employed to unambiguously confirm erinacine A in the isolated fractions, while HPLC with a charged aerosol detector (CAD) was used to determine its purity. Given the limited commercial availability and the high price of erinacine A, the described method offers a straightforward and cost-effective alternative to obtain this valuable compound for further research and applications. Full article

Infrared thermography is a real-time and efficient method for defect detection. This study utilizes line laser scanning infrared thermography to detect cracks in manually laid-up unidirectional CFRP, 3D-printed CFRP cracks, and naturally occurring microcracks in CFRP deflectors. In manually layered unidirectional CFRP, detection performance is influenced by the layup direction, with cracks aligned to the layup exhibiting minimal hindrance to heat conduction, resulting in weaker high-frequency components in thermal images and poorer detection accuracy. In contrast, the composite structure of 3D-printed CFRP minimizes the impact of crack orientation. By analyzing the temperature characteristics of the crack center and thermal drag tail for cracks with varying opening angles, the study establishes a relationship between the crack opening angle, crack depth, and thermal features. Fitted curves of the ratio between crack opening angle and absolute temperature difference yielded an average R² of 0.9828 and MSE of 0.1287, validating the effectiveness of the proposed approach. Finally, the features of microcracks in CFRP deflector plates were effectively extracted through high-frequency filtering, which demonstrated the broad applicability and robustness of this study. Full article