Search Results (17,504)

Intralayer hybridisation provides a powerful strategy for tailoring the stiffness–strength–ductility balance of fibre-reinforced composites through architecture control. This study investigates the flexural behaviour of carbon/glass intralayer hybrid composites with varying carbon-to-glass (C:G) ratios and degrees of dispersion using a finite element modelling framework supported by experimental validation against published flexural test data. Four hybrid ratios (C:G = 2:1, 1:1, 1:2, and 1:4) and multiple dispersion levels were examined under three-point bending to quantify the effects of intralayer architecture on flexural strength, modulus, and strain to failure. The results show that carbon-rich hybrids retain high flexural stiffness and strength while achieving substantial improvements in failure strain and damage tolerance compared with pure carbon laminates. In these systems, flexural strength is strongly influenced by dispersion, with moderate-to-high dispersion improving strain compatibility, delaying tensile-side carbon fibre fracture, and enhancing strength. In contrast, glass-dominated hybrids exhibit flexural behaviour that is largely insensitive to dispersion, with strength and modulus following near rule-of-mixtures trends and failure governed by progressive glass fibre and matrix damage. Across all hybrid ratios, flexural modulus is controlled primarily by fibre volume fraction, whereas flexural strength and failure strain depend sensitively on intralayer architecture when carbon fibres remain the dominant load-bearing phase. These findings clarify the respective roles of hybrid ratio and dispersion in governing flexural performance and extend recent studies by demonstrating a systematic transition from dispersion-dominated to ratio-dominated behaviour as glass content increases. The results provide mechanistic insight and practical design guidance for optimising intralayer hybrid composites for lightweight, damage-tolerant structural applications. Full article

We report the development of bundled optical-guiding crystal scintillators (OCSs) with ultrafine and uniform scintillator cores (~12 μm) for high-resolution X-ray imaging. Conventional OCS fabrication using iodide scintillators often suffers from iodine volatilization, bubble formation, and core discontinuities, which limit structural uniformity and device reliability. To address these limitations, a hollow-fiber-based fabrication strategy was introduced. Hollow glass fibers were first bundled and drawn without scintillator materials, followed by capillary infiltration of a Tl-doped Cs₃Cu₂I₅ (Tl: CCI) melt. This approach enabled the stable formation of densely packed bundled OCS structures with uniform core diameters of 10–12 μm while suppressing volatilization-induced defects. Radioluminescence measurements confirmed a broad emission peak at ~442 nm, consistent with Tl:CCI scintillation. X-ray imaging experiments demonstrated superior spatial resolution and image contrast compared with a commercial CsI:Tl columnar scintillator. The bundled OCS exhibited an average contrast transfer function (CTF) of 30.7% at ~10 lp/mm, exceeding the reference value. These results demonstrate that the hollow-fiber architecture provides an effective route toward scalable ultrafine-core scintillators and highlight the potential of Tl:CCI-filled OCSs for next-generation high-resolution X-ray imaging. Full article

Background/Objectives: Color vision deficiency (CVD) arises from the absence or dysfunction of one or more cone photoreceptors in the retina, resulting in impaired color discrimination. Although inherited CVD cannot be cured, optical compensation strategies such as color-filtering glasses have been developed to enhance color perception. However, quantitative clinical evaluations of their corrective efficacy remain limited. This study aimed to assess the effectiveness of notch filter-based color blind glasses in improving color perception and discrimination in individuals with CVD. Methods: Notch filters were employed as color correction lenses, and clinical assessments were conducted to evaluate their impact on human color perception. Subjects underwent standardized color vision tests, including the Color Bridge test, Farnsworth-Munsell 100 Hue test, and D-15 panel test, both before and after wearing the glasses. Outcomes were quantitatively analyzed using total error score (TES), confusion angle, and confusion index (C-index) to determine changes in color discrimination performance. Results: Quantitative analysis demonstrated that wearing the notch filter glasses amplified color differences along confusion lines. In clinical trials, 83% of subjects showed improved color discrimination in the F-M 100 Hue test, with TES reductions between 6.67% and 50.00%. Furthermore, D-15 panel testing revealed that 67% of participants exhibited a decreased C-index and reduced scatter index (S-index), with specific cases shifting from deficient to normal color perception (C-index < 1.6). These results indicate that the filters effectively mitigate symptoms of color vision deficiency by increasing perceptual contrast. Conclusions: Notch filter-based color correction glasses can enhance chromatic discrimination in individuals with CVD by increasing perceptual color contrast. These findings provide practical insights for the optimization and fabrication of color vision correction eyewear utilizing spectral notch filtering strategies. Full article

Poly(ethylene terephthalate) (PET) composites reinforced with reduced graphene oxide (rGO) were investigated in order to elucidate the influence of nanofiller concentration and compatibilization on the viscoelastic relaxation behavior across the glass transition. Composites containing 0.1 and 0.5 wt% rGO were prepared by melt blending, and selected systems incorporated 5 wt% of an ionomeric polyester (PETi) as compatibilizer to enhance interfacial adhesion. The thermomechanical response was characterized using dynamic mechanical analysis (DMA) as a function of temperature. Experimental results revealed a strong dependence of stiffness, damping, and glass transition behavior on filler concentration and interfacial interactions. While low rGO loading produced minor changes, the incorporation of 0.5 wt% rGO significantly increased the glassy modulus and shifted the glass transition temperature, indicating restricted segmental mobility. Compatibilized systems exhibited further stiffness enhancement and modified relaxation dynamics due to improved stress transfer and interphase development. To capture the distributed nature of the relaxation processes, the glass transition region was modeled using a fractional Zener model (FZM) with two spring-pot elements within a cooperative relaxation framework. The model successfully reproduced the experimental $E^{\prime }$ and $tan\delta$ curves and revealed systematic variations in the fractional exponents and cooperative parameters. The results demonstrate that the introduction of rGO and compatibilizer progressively transforms the relaxation spectrum of PET from a relatively uniform segmental process into a heterogeneous, interfacially mediated viscoelastic response that is naturally described by fractional rheology. Full article

The electrolytic aluminum industry is facing severe challenges, such as excessive carbon consumption, resulting in more cost and environmental pollution due to the oxidation of carbon anodes. The isothermal oxidation resistance of B₄C-SiO₂-Albite (BSA) composite coating influenced by the in situ formation behavior and self-healing ability of the borosilicate glass at 1173 K was investigated through XRD, TG-DSC, Raman, FTIR spectroscopy, and SEM/EDS in this paper. The results show that the composite coating with 20 wt% B₄C has a relatively low mass gain rate of −0.082% after 24 h at 1173 K. It depends on the in situ formation of the amorphous borosilicate phase layer that can effectively protect the carbon anode from oxidation, which depends on the content of B₄C. The amorphous borosilicate glass forms from the reaction between the SiO₂ and the B₂O_3, from the oxidation of B₄C during exposure. More B₄C promotes the formation and volatilization of B₂O₃, which improves the viscosity and stability of the borosilicate glass by changing the glass network coupled with Na⁺ and Al³⁺ from Albite. It is a feasible strategy for designing durable coatings with appropriate B₄C addition for high-temperature applications. Full article

This study evaluates how titanium and polymethyl methacrylate (PMMA) Boston Keratoprosthesis backplate substrates influence human corneal fibroblast proliferation, cytotoxicity, morphology, activation phenotype, and mechanotransductive signaling. Human corneal fibroblasts were cultured on titanium and PMMA, with tissue culture plastic or glass as controls. Proliferation was assessed over 7 days using metabolic assays, and cytotoxicity was measured by lactate dehydrogenase release. Cell morphology and surface coverage were examined by scanning electron microscopy, while immunofluorescence quantified fibroblast-specific protein 1 (FSP-1) and α-smooth muscle actin (α-SMA). Gene expression of α-SMA, collagen I, FSP-1, and focal adhesion kinase (FAK) was analyzed by quantitative PCR. Cells cultured on both substrates maintained stable viability with modest increases in estimated cell numbers and comparable proliferation curves, indicating preserved metabolic activity without growth suppression. Cytotoxicity remained low and similar between groups. SEM demonstrated broader and more continuous cell spreading on titanium, whereas cells on PMMA were more sparsely distributed. Immunofluorescence showed higher FSP-1 expression on titanium and increased α-SMA on PMMA. Gene expression analysis revealed higher FAK transcripts on PMMA, with no significant differences in α-SMA, FSP-1, or collagen I. These results confirm the cytocompatibility of both titanium and PMMA backplates with human corneal fibroblasts and support their use with the Boston Keratoprosthesis. Full article

Gum arabic (GA) is a widely used natural hydrocolloid in food processing because its protein–polysaccharide architecture combines high water solubility, low bulk viscosity, and useful interfacial activity. These attributes make GA valuable as an emulsifier, encapsulating agent, and film-forming material, but native GA is constrained by source-dependent heterogeneity, limited antioxidant functionality, relatively high dosage requirements in some emulsions, and modest barrier and mechanical performance in dried matrices. This review synthesizes recent advances in chemical functionalization, enzymatic and oxidative grafting, physical fractionation and complexation, and Maillard-type bioconjugation as routes to tailor GA for food engineering applications. Emphasis is placed on process-relevant structure–property relationships, including dynamic adsorption, interfacial rheology, emulsifying and encapsulation efficiency, bulk rheology, powder glass transition and hygroscopicity, film barrier behavior, and release kinetics. Across beverage emulsions, spray-dried powders, coacervates, coatings, and delivery systems, the evidence shows that modification must be selected according to the dominant process bottleneck, such as adsorption kinetics, oxidative stability, drying behavior, or humidity-sensitive matrix mobility. This review also identifies priorities for translation, including model-ready measurements, the management of raw-material variability, scale-up-aware processing, and sustainability and regulatory practicality. Overall, modified GA emerges as a versatile platform for designing more robust, application-specific food colloids, encapsulates, and functional coatings. Full article

While both Urbach tails and dangling bonds are known to be present in a-Si films, the current literature lacks parametrization that simultaneously accounts for both types of defects using only transmittance spectra, reflectance spectra, or spectroscopic ellipsometry. To address this issue, we performed parametrizations of three magnetron-sputtered a-Si thin films deposited on glass substrates at different low pressures of argon gas, using only their measured UV–Vis–NIR transmittance spectra T(λ = [300, 2500] nm) and different dispersion models. We preprocessed T(λ) by suppressing both general and bandpass noise to yield the spectrum T_d(λ). The films were parametrized from T_d(λ) using two versions of the Tauc–Lorentz–Urbach dispersion model and the universal dispersion model (UDM) of Franta. The most accurate parametrization was achieved employing UDM including Urbach tail and three subgap oscillators. JDOS and the dielectric function ε(E) were computed by this UDM, and it was concluded that these three oscillators correspond to electron transitions via two bands of dangling bonds. The respective DOS is similar to the DOS previously reported for a-Si:H, but not to a-Si, indicating a relatively low density of dangling bonds in our a-Si films. Record low parametrization errors are achieved, which confirms the accuracy of these results. Full article

The brittleness of bismaleimide (BMI) resin is a major issue that restricts its use as a matrix for advanced composites. Blending with thermoplastics constitutes an effective toughening approach that preserves the thermal resistance and mechanical properties of the resin. Reaction-induced phase separation is the primary toughening mechanism in thermoplastic-toughened BMI resin. However, the complex phase-separated structure causes the relationship between the glass transition temperature (T_g) and the curing degree to deviate from that described by the classical DiBenedetto equation. In this paper, two improved models, incorporating power-law correction and threshold inhibition, were constructed to address the phase-separation effect. An aerospace-grade BMI resin was toughened by a thermoplastic polyimide. The relationship between T_g and the curing degree was fitted by the DiBenedetto equation and the improved models. It was found that the adjusted coefficient of determination for the power-law correction and threshold inhibition models for the toughened resin increased to 0.978 and 0.995, respectively, whereas that of the DiBenedetto equation was only 0.612. This work provides a new, readily applicable empirical model for the prediction of T_g in thermoplastics-toughened thermosetting resins and offers theoretical support for optimizing the curing process and controlling the performance of multiphase resins. Full article

Studies on the influence of radiotherapy on the structure, thermal properties, and thermo-oxidative decomposition of breast silicone implants were conducted. Additionally, the potential use of breast silicone implant waste as a component in layered composites was investigated. ATR-FTIR, DSC, and TG/DTG/FTIR analyses confirmed that radiation does not affect the structure, thermal properties, or oxidative decomposition behavior of the shell and gel layers of breast silicone implants. The conducted tests demonstrated the successful fabrication of composite materials using a PUM matrix and breast silicone implant waste. The presence of the PUM matrix in the manufactured composites influenced the crystallization and melting behavior of the silicone phase. Moreover, the incorporation of a silicone implant waste layer into the composites increased their thermal stability while decreasing the glass transition temperature, storage modulus and hardness compared to neat PUM. The type of implant waste layer used (shell or gel) in the preparation of the PUM composites did not significantly affect the melting and glass transition temperatures, thermal stability, or oxidative decomposition behavior of the newly developed materials. As demonstrated, new layered composite materials based on silicone implant waste (shell and gel), with properties valuable for practical applications, were successfully developed. Full article

The long-wave infrared band, which at room temperature covers the infrared radiation of humans and objects, has significant applications across various fields including wireless communication, national defense, military, biomedical, and advanced driver assistance systems. Metalens provides a pathway to lightweight, compact, and integrated solutions for infrared imaging and sensing systems, marking an inevitable trend in future development. This study presents a design for a high numerical aperture of 0.89 in a polarization-insensitive all-chalcogenide metalens operating at 10 µm, utilizing the commercially available chalcogenide glass material As₂Se₃ via a transmission phase approach. Building upon this, we have achieved, for the first time, a high numerical aperture of 0.84 for an all-chalcogenide broadband LWIR achromatic metalens operating in the 9.5–10.5 µm range, with significantly improved focusing performance through the application of particle swarm optimization algorithms. The superior performance of the all-chalcogenide LWIR metalens, combined with the advantages of chalcogenide glass over traditional LWIR materials such as Si or Ge—namely, lower cost, reduced optical loss, and a smaller thermo-optic coefficient—suggests it has significant potential for broader applications. Full article

Magic lantern slides are fragile objects consisting of transparent images depicted on thin glass plates to be projected by magic lanterns. Despite their widespread presence in archives and museums, these collections are often undervalued and understudied. The Portuguese Cinematheque holds the most extensive collection of slides in Portugal. This article presents the first preventive conservation case study focused on the collection of painted slides, reflecting on the general origins of this collection, examining the challenges faced by caretakers when adapting historical buildings to accommodate collections of this nature. Environmental monitoring of light and radiation, temperature, and relative humidity in storage and exhibition rooms was combined with ultraviolet-visible spectroscopy to measure the fading of one of the most light-sensitive colours identified in these slides in previous studies, the pink eosin-based lake, by comparing a slide exhibited under the measured light conditions with one kept in storage during the same period. The results identified damaging light exposure in display areas with illuminance values far above the recommended levels for these materials, and significant RH fluctuations in both spaces. These conditions are consistent with deterioration factors known to affect the material that composes these fragile media (e.g., light-sensitive painting materials and organic frames, and unstable glass). This study also showcases how raising awareness on the fragility of this heritage stimulated discussions and encouraged small and feasible changes that can positively impact its preservation. Full article

Mg-doped ZnO (Zn_1−xMg_xO, x = 0.00–0.05) thin films were successfully grown on glass substrates with a c-axis orientation at 600 °C using the sol–gel dip-coating technique. The structural features, defect-related photoluminescence, and optical constants of the films were systematically investigated as a function of Mg concentration. X-ray diffraction (XRD) patterns confirmed a single-phase hexagonal wurtzite structure with a preferential (₀₀₂) orientation for all compositions, indicating the successful substitution of Mg²⁺ ions into the ZnO lattice. The crystallite size (D₀₀₂) was found to vary between 28.49 and 41.18 nm, while microstrain and stress exhibited non-monotonic behavior depending on Mg content. This behavior reveals a transition from compressive to tensile stress due to lattice distortion and defect formation. Photoluminescence (PL) spectra showed a dominant near-band-edge (NBE) ultraviolet emission, along with broad visible emissions extending from violet to red. Optical constants were accurately extracted using a double-facet-coated substrate (DFCS) model, combined with nonlinear curve fitting using the Nelder–Mead optimization algorithm. The films showed a strong absorption edge at about 370 nm and exceptional optical transparency (≈60–80%) in the visible spectrum. The systematic blue shift in the extinction coefficient with increasing Mg content confirms bandgap engineering in Zn_1−xMg_xO thin films. The refractive index dispersion was successfully modeled using the Cauchy relation, demonstrating composition-dependent tunable optical properties. Depending on the Mg content, the optical bandgap values ranged from approximately 3.265 to 3.315 eV. The band-edge states and optical constants are strongly affected by the combined effects of defect development, Mg-induced lattice distortion, and changes in optical dispersion. These results indicate that sol–gel-derived Mg-doped ZnO thin films with composition-dependent stress states, defect states, and tunable optical properties are promising candidates for UV photodetectors, optical coatings, and transparent optoelectronic devices. Full article

Background/Objectives: Accurate intraoperative tumour localisation remains challenging in minimally invasive colorectal surgery, where conventional tattooing methods suffer from marker migration, tissue diffusion, and potential allergic reactions. Radio frequency identification (RFID) technology offers a promising alternative through implantable passive transponders detectable via electromagnetic coupling, eliminating ionising radiation exposure. Methods: This preclinical feasibility study evaluated three RFID frequency bands for surgical tumour marking: 134 kHz (low frequency, LF), 13.56 MHz (high frequency, HF), and 868 MHz (ultra-high frequency, UHF). Finite element electromagnetic simulations characterised antenna field distributions, while experimental validation employed glass-encapsulated transponders in air and tissue-simulating saline (0.9% NaCl, σ ≈ 1.5 S/m). Detection ranges were measured across 28 angular configurations with expanded measurement uncertainty (k = 2) ranging from ±0.9 to ±3.2 mm. Results: Maximum detection distances in air were 25.0 ± 0.9 mm (LF), 23.0 ± 1.1 mm (HF), and 68.0 ± 2.3 mm (UHF). In saline, ranges decreased to 22.5 ± 1.0 mm, 20.7 ± 1.2 mm, and 18.0 ± 1.4 mm, respectively, demonstrating tissue attenuation of 10% at LF/HF vs. 74% at UHF. Angular characterisation revealed 64–70% range reduction at orthogonal orientation for LF/HF systems. Computational–experimental correlation yielded r² = 0.975 across 154 paired observations. Conclusions: The 13.56 MHz HF band emerges as the optimal candidate for clinical translation, offering adequate tissue penetration (20.7 mm), superior antenna miniaturisation potential (5 mm diameter), established biocompatibility pathways, and mature near-field communication ecosystem support. Future development should address angular sensitivity through multi-axis antenna configurations and validation in anatomically realistic tissue phantoms. This study establishes the electromagnetic evidence base for clinical system development; translation to clinical practice requires sequential preclinical and clinical evaluation. Full article