Search Results (64,350)

This paper presents an evaluation of two new approaches to improve the surface quality and the mechanical properties of ceramic parts printed by fused deposition of ceramic (FDC). Dip-coating and aerosol-treatment are performed in order to reduce the staircase effect in the vertical printing direction, which typically represents the weakest orientation in most additive manufacturing processes, particularly in fused filament fabrication (FFF). The post-treatments are applied on two highly filled alumina feedstocks. A commercial aerosol-treatment machine for fused deposition modeling is used with ethanol as solvent. A suspension composition for dip-coating is developed to reduce the surface roughness without compromising the printing resolution. The influence of these post-processing steps on the mechanical properties and surface roughness of the green and sintered parts is investigated using perthometer measurements and four-point bending tests in the vertical build direction on as-processed, aerosol-treated, and dip-coated samples. The mechanical results are compared to extruded strand samples. An improvement in surface quality is achievable by dip-coating despite reduction in the parts strength, with a reduction of 65% of the R_z values in the sintered state compared to untreated samples. Aerosol-treatment neither improves the surface quality nor the mechanical properties of the parts. The feedstock and post-processing steps developed in this research aim at printing dense ceramic parts with high surface quality, serving as a basis for developing ceramic parts with higher strength. This advancement will facilitate the utilization of FDC in structural and aesthetic design applications. Full article

This study investigates the formation and soot removal properties of four composite materials derived from alloy glasses in the system of Zr-Pd-Pt-Ce. Amorphous Zr₆₅Pd₃₅, Zr₆₅Pd₃₀Pt₅, Zr₆₀Pd₃₅Ce_5, and Zr₆₀Pd₃₀Pt₅Ce₅ were subjected to a heat treatment at 800 °C for 3 h in air, resulting in the formation of composites containing PdO, Pd and a mixture of tetragonal and monoclinic ZrO₂ phases. Their microstructure was identified as composites in which PdO (Pd) precipitates are were dispersed in a ZrO₂ matrix. The oxidation of soot over the composites was initiated at lower temperatures, reaching the completion of removal at approximately 600 °C, which was superior to that of non-catalytic soot combustion. The sequence in which the removal temperatures decreased was as follows: Zr₆₅Pd₃₅ > Zr₆₀Pd₃₅Ce₅ > Zr₆₀Pd₂₅Pt₅Ce₅ > Zr₆₅Pd₃₀Pt₅. The microstructure emerges as the predominant factor influencing soot oxidation activity, where the oxidation reaction rate was mainly governed by the interface length between PdO and ZrO₂. The present results identified a novel bulk-type catalytic composite material, which was derived by a simple process from alloy glasses for the purpose of low-temperature soot oxidation. Full article

The interaction between plasmonic nanoparticles and organic dye molecules plays an important role in varied photonic and optoelectronic applications. In this work, we systematically investigate the optical properties of a water-soluble perylenediimide derivative, N,N′-di(2-(trimethylammonium iodide) ethylene) perylenediimide (TAIPDI), in the presence of different concentrations of silver nanoparticles (AgNPs) under femtosecond (fs) laser excitation. The AgNPs were synthesized via the laser ablation technique. The influence of AgNP concentration on the linear, fluorescence, and nonlinear optical properties of the TAIPDI dye was explored through UV–visible absorption spectroscopy, fluorescence emission measurements, and open- and closed-aperture Z-scan techniques. The Ag NP–TAIPDI dye hybrid systems (Ag@TAIPDI nanocomposites) exhibited pronounced reverse saturable absorption and self-defocusing behavior, indicating a negative nonlinear refractive index. Both the nonlinear absorption coefficient and refractive index increased markedly with rising AgNP concentration, leading to a significant enhancement in the third-order nonlinear susceptibility. Fluorescence studies further revealed a concentration-dependent emission enhancement due to metal-enhanced fluorescence arising from surface plasmon resonance-induced local field amplification. The Ag@TAIPDI nanocomposites also demonstrated strong optical limiting performance, with the limiting threshold decreasing as the AgNP concentration increased. These findings highlight the synergistic role of plasmon–exciton coupling and thermal lensing in enhancing the nonlinear response of such nanocomposites. The results establish AgNPs–TAIPDI dye hybrid systems as promising materials for all-optical switching, optical limiting, and photonic device applications. Full article

Using disposable screen-printed electrodes faces major challenges when attempting to monitor a continuous process, especially in systems where there is pronounced adsorption, fouling, degradation, or in cases of irreversible electrochemical reactions. Methylene Blue (MB) exhibits some therapeutic properties and is commonly used as a redox reporter in DNA sensors, but is also considered a toxic pollutant in aquatic systems. MB demonstrates strong adsorption to carbon materials, which prevents its electroanalytical determination in multiple measurements with a single electrode. Our work details direct electrochemical determination of MB with only the native carbon screen-printed working electrode as sensing material and optimization of the analytical method. In batch mode, we significantly improved sensitivity and interelectrode reproducibility by introducing a prepolarization step, but successive measurements in lower concentrations were not feasible due to strong adsorption. A fully customizable, modular flow cell was 3D printed to allow in operando replacement of the planar screen-printed three-electrode system after measurement during continuous flow. As confirmed by mechanical properties testing, the rigid polyacrylate upper section of the flow cell provides structural stability, combined with a flexible TPU lower section which enables effortless sensor hot swapping and effective sealing during flow. With an optimized hot swapping flow detection method, MB was detected via square wave voltammetry with a sensitivity of 65.59 µA/µM and a calculated LOD of 7.75 nM, which outperforms similar systems from the literature. We envisage this approach can be integrated into low-cost continuous environmental monitoring systems or in-line quality control, especially in flow chemistry synthesis. Full article

Conventional hepatocellular carcinoma (HCC) treatments suffer from insufficient efficacy and severe toxic side effects. This review addresses these issues by focusing on gel microsphere-mediated photodynamic therapy (PDT) as a novel strategy. It outlines the core properties, classifications, and stimulus-responsive mechanisms of gel microspheres, as well as their structure-function compatibility with photosensitizers. The work highlights how gel microspheres enable targeted delivery, tumor microenvironment-responsive release, and synergistic effects with chemotherapy, radiotherapy, and immunotherapy to enhance therapeutic efficacy while reducing off-target damage. Additionally, it discusses current challenges including material parameter controllability and clinical translation hurdles, providing insights for the development of precise and personalized HCC treatments. Full article

Low-saturated hydraulic conductivity covers (LSHCC) or hydraulic barriers are one of the reclamation techniques used to control the acid mine drainage generation (AMD). These covers are intended to limit the infiltration of water into reactive tailings. Compacted clays are among the materials used as LSHCC. The performance of clay-based hydraulic barriers can be affected by their geotechnical and hydrogeological properties. Freeze–thaw cycles can increase their saturated hydraulic conductivity (k_sat). However, these effects can be minimized by adding amendments. To evaluate the performance of these clay-based covers, four field experimental cells were built. The first one simulates a cover composed entirely of clay, the second a clay–silt mixture, the third a clay–sand mixture and the last two layers of clay with an intermediate layer of silt. Each cell has been equipped with a monitoring station with continuous measurements of volumetric water content, suction and temperature. In situ permeability tests were also conducted to assess field hydraulic conductivity. Numerical simulations were also conducted to evaluate the water balance for each cover scenario. The laboratory results showed low-saturated hydraulic conductivity values meeting waterproofing criteria, whereas field measurements and calibrated model values were consistently higher and exceeded the waterproofing criteria. Infiltration monitoring indicated that 15 to 40% of precipitation infiltrated the covers, with possible overestimation due to preferential flow. Discrepancies between laboratory and field-saturated hydraulic conductivity values were mainly attributed to inadequate compaction, unfavorable weather conditions, and excessive water content during cover installation. Variations in saturated hydraulic conductivity over time were generally within statistical variability, although differences among cells and responses to wetting–drying cycles highlight the influence of construction conditions on field performance. Full article

Sweet potato (Ipomoea batatas L.) is cultivated globally and generates a large quantity of plant-derived residues, including leaves, stems, and non-commercial cull roots, which remain insufficiently utilized despite their potential functional value. Although the antioxidant properties of sweet potato leaves have been reported, comparative investigations of different plant parts evaluated under the same experimental conditions, particularly in relation to skin-associated biological functions, are still limited. In this study, aqueous extracts prepared from sweet potato leaves, stems, and cull roots were obtained using a food-grade extraction process suitable for practical application. The phenolic composition and biological properties of the extracts were comparatively analyzed. Antioxidant capacity was examined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, ferric reducing antioxidant power (FRAP), as well as assays associated with superoxide dismutase (SOD)-like and catalase-related activities. Skin-related biological responses were further evaluated by measuring elastase and collagenase inhibition, type I procollagen synthesis, and matrix metalloproteinase-1 (MMP-1) secretion in CCD-986Sk human dermal fibroblasts. Among the tested samples, the leaf-derived aqueous extract exhibited a higher total phenolic content, greater accumulation of chlorogenic acid, and stronger antioxidant responses compared with stem and cull root extracts. In addition, the leaf extract showed more pronounced effects on collagen metabolism, including enhanced procollagen synthesis and reduced MMP-1 secretion, while maintaining acceptable cell viability within the tested concentration range. Overall, these results demonstrate clear tissue-dependent functional differences among sweet potato residues and indicate that leaf-derived extracts represent a promising functional material for skin-related and cosmetic applications. Full article

Recently, epoxy resin concrete (ERC) has shown significant potential in rapid repair applications, such as bridge expansion joints, owing to its early strength gain, rapid hardening, excellent adhesion, and durability. Based on the background of rapid repair scenarios for small- and medium-span bridges, this study designed a mix proportion of ERC. A systematic investigation was conducted on its mechanical properties and constitutive model under various curing temperatures (5 °C, 20 °C, and 35 °C) and ages. Experimental results indicate that the designed ERC cures within 2 to 6 h and achieves a compressive strength of 15 MPa at 1 day, meeting the requirement for early traffic reopening. Both material strength and elastic modulus increase significantly with age, reaching a compressive elastic modulus of 16 GPa at 90 days. Based on the measured uniaxial compressive and tensile stress–strain data, a temperature-dependent constitutive model was established. The fitting parameters exhibit a quadratic functional relationship with curing temperature. The model demonstrates high fitting accuracy under all tested conditions (R² ≥ 0.9293). This study provides a theoretical basis and data support for the application and numerical simulation of ERC in bridge engineering. Full article

To enhance the rheological properties and engineering applicability of fully solid waste filling slurry, this study uses iron tailings sand as aggregate and slag, steel slag, and desulfurization ash as cementing materials. Through a central composite design experiment, the synergistic regulatory effects of steel slag (10~30%) and desulfurization ash (10~30%) on the slurry’s rheological and strength properties were systematically investigated. The yield stress and plastic viscosity of the slurry were quantified based on the Bingham fluid model, using expansion tests and L-tube models, while isothermal calorimetry analysis and microscopic image processing revealed the underlying micro-mechanisms. The results show that when both steel slag and desulfurization ash contents are 20%, the cured specimen prepared from the slurry achieves an optimal 28-day uniaxial compressive strength of 5.90 MPa at 28 days, with yield stress and plastic viscosity of 146.71 Pa and 3.04 Pa·s, respectively. Micro-mechanistic analysis revealed that desulfurization ash effectively reduced the yield stress by up to 38% (from 196.04 Pa to 90.01 Pa) and increased the fractal dimension of flocculated structures to 1.906, thereby optimizing initial flowability. Conversely, steel slag increased the yield stress but decreased plastic viscosity, enhancing structural stability, and regulating the later hydration process. The loop tests confirmed the good transport performance and engineering adaptability of the optimized mix, achieving a cost reduction of up to 65% compared to cement-based systems. Full article

The widespread occurrence of emerging mycotoxins (EMs) produced by Fusarium, Aspergillus, and Penicillium species has raised increasing concerns regarding food and feed safety. Mitigation strategies currently applied to control regulated mycotoxins in feed may also be effective in reducing contamination by EMs. This study comparatively evaluated the in vitro adsorption efficacy of two leonardites, eight natural smectites, and two modified clays (organoclays) against EMs produced by Fusarium, Aspergillus, and Penicillium spp. All materials were tested at two inclusion levels (0.1 and 0.5% w/v) under two pH conditions (pH 3 and 7), simulating the gastrointestinal environment of monogastric animals. Adsorption performance was strongly influenced by mycotoxin chemistry, adsorbent type, inclusion rate, and medium pH. Organoclays exhibited the highest and most consistent efficacy, achieving near-complete adsorption of beauvericin (BEA) and enniatins (ENNs) (>98–100%) at 0.1% (w/v), as well as high removal of mycophenolic acid (MYC. A.) and citrinin (CIT) (>90%) across both pH conditions. Natural smectites showed high but more selective adsorption, removing >90% of BEA and ENNs at low inclusion rates, while displaying limited efficacy toward fusaric acid (FA) and patulin (PAT). Leonardites demonstrated intermediate and material-dependent performance; leonardite L1 adsorbed approximately 90% of BEA at 0.1% (w/v), whereas ENN adsorption ranged from ~36% to 80% at the same inclusion rate and exceeded 90% only at higher dosages. None of the tested materials effectively adsorbed patulin (PAT) at pH 7; however, at pH 3, four smectites exhibited partial adsorption, and one trioctahedral smectite achieved more than 90% PAT adsorption under acidic conditions. Overall, organoclays displayed the broadest adsorption spectrum across structurally diverse mycotoxins, while smectites exhibited high selectivity driven by surface charge density and interlayer interactions. Leonardite-based materials showed moderate but highly variable adsorption performance, likely influenced by heterogeneity in humic functional groups and physicochemical properties. These findings highlight the need for tailored adsorbent selection or combined mitigation strategies to achieve effective mycotoxin control in the animal feed industry. Full article

The construction sector is a major user of natural materials and a key contributor to global carbon emissions. To tackle these environmental challenges, the use of recycled products has become increasingly important in modern engineering. Cellular glass aggregate (CGA), made from recycled glass, is a material with potential as a sustainable alternative to natural aggregates. This study characterizes the cyclic behavior of CGA using a large-scale triaxial apparatus, focusing on seismic-relevant properties such as the damping ratio and Young’s modulus. Local displacement transducers (LDTs) were implemented to improve measurement at small strains. The results show that CGA exhibits strain-dependent stiffness and damping behavior comparable to natural aggregates at moderate strains (10⁻⁴–10⁻³). The Young’s modulus ranges from approximately 300 to 600 MPa, while damping ratios remain at approximately 2–3% for low values of strains (10⁻⁵). As strain increases to moderate levels (10⁻⁴–10⁻³), the Young’s modulus decreases to approximately 80–250 MPa, accompanied by an increase in damping ratio to approximately 4–6%. At higher strain levels ≥ 10⁻³, the Young’s modulus further reduces to approximately 40–80 MPa, while damping ratios increase to approximately 7–10%. These stiffness degradation and damping trends fall within the ranges reported for sands and gravelly soils in the literature, indicating that CGA can reproduce the cyclic mechanical behavior of natural aggregates under well-defined strain conditions. Full article

Lead-free perovskite solar cells have become attractive as they are more environmentally friendly than their lead-based counterparts. Among these lead-free perovskite materials is MASnI₂Br, which has attracted considerable attention due to its environmentally friendly advantages and beneficial optoelectronic properties. However, further enhancement is required in order to improve the power conversion efficiencies. In this study, an MASnI₂Br-based perovsdkite solar cell is designed and optimized using SCAPS-1D simulations. An extensive iterative simulation approach is carried out to optimize critical parameters such as electron affinity, energy bandgap, layer thickness and doping concentration for both transport layers. In addition, the thickness of the MASnI₂Br absorbing layer is optimized. With the improved device setup, the maximum achievable power conversion efficiency is 24%. Furthermore, by matching the optimized electronic structure with realistic transport materials, CBTS and TiO₂ are identified as suitable hole and electron transport layers, respectively. The proposed TiO₂/MASnI₂Br/CBTS perovskite solar cell has a power conversion efficiency of about 23.6%. Full article

Hyperspectral imaging in the long-wave infrared (LWIR) range enables identification of chemical compositions and material properties, but reconstructing 3D models from gimballed pushbroom sensors remains challenging because their unique acquisition geometry is incompatible with conventional photogrammetric software designed for frame cameras. This study presents a workflow for creating explorable 3D models from multi-angle LWIR hyperspectral imagery by co-registering hyperspectral line-scan data with simultaneously acquired RGB frame camera imagery using deep learning-based image matching. The co-registered images are processed in commercial photogrammetric software (Agisoft Metashape), and a texture-to-image mapping algorithm preserves correspondences between 3D model coordinates and original hyperspectral pixels across multiple viewing angles. Quantitative evaluation against reference data demonstrates that co-registration reduces geometric error approaching the accuracy of models built from high-resolution RGB imagery. The resulting models enable the retrieval of 8–50 spectral signatures per surface point, captured from different viewing geometries. This approach facilitates interactive exploration of angular variations in thermal infrared spectra, supporting material identification for non-Lambertian surfaces where single-angle observations may be insufficient for reliable classification. Full article

Background: This in vitro study compared color stability, surface properties, and microbial adhesion of four gingival epithesis materials (silicone: Gingivamoll^®; nylon: Valplast^®; PETG-based high-performance polymer: Eldy Plus^®; PMMA: Palapress^®) after staining. Methods: Standardized specimens (10 × 10 × 2 mm; n = 18/material) underwent 15 or 30 staining cycles (sequential immersion in coffee, curry, tea, and 40% alcohol). Color (CIELAB) and color difference (ΔE00), gloss (G), and surface roughness (Ra) were measured at baseline and after 15 and 30 cycles; surface morphology was assessed by SEM. Microbial adhesion was assessed using a six-species biofilm model and quantified as log CFU at baseline and after 15 and 30 cycles. Results: All materials showed clinically relevant discoloration (ΔE00 > 2). Valplast^® exhibited the greatest color change (p < 0.05), while color change in other materials remained lower. Gingivamoll^® showed the lowest gloss and highest roughness, whereas other materials remained smoother; roughness increased significantly over time (p < 0.05). SEM revealed a coating on the hard materials and nodular agglomerates on silicone. Biofilm CFU did not differ over time or between materials (all p > 0.05). Conclusions: Staining induced material-dependent changes in color and surface properties, with Valplast^® most prone to discoloration and silicone showing high roughness and nodular surface changes, contrasting with coatings on hard materials. Microbial adhesion analysis yielded pilot-level results, intended to inform the design of future investigations. Full article

Valvular heart disease remains a major global health burden, with currently available prosthetic heart valves failing to fully reproduce the adaptive, regenerative, and long-term functional properties of native valves. Tissue-engineered heart valves (TEHVs) have emerged as a promising alternative, aiming to develop living valve replacements capable of growth, remodeling, and physiological integration. However, despite substantial progress, the clinical translation of TEHVs remains limited, indicating the need for design strategies that go beyond material selection toward functionally mature constructs. This review presents recent advances in TEHV development from a biomimetic perspective, using native heart valves as a biological reference characterized by hierarchical structure, anisotropic mechanical behavior, mechanoresponsive cell populations, immune regulation, and temporally coordinated remodeling. We integrate current understanding of valve biology and mechanobiology with advances in scaffold materials and architecture, bioactive functionalization, biomechanical conditioning, and emerging fabrication and monitoring technologies. We discuss how biomimetic scaffold designs aim to replicate native extracellular matrix organization and nonlinear mechanics, how biological cues are used to regulate thrombosis, immune response, and cell recruitment, and how dynamic bioreactor systems support functional tissue maturation through controlled mechanical stimulation. Finally, key challenges for clinical translation are highlighted, and future directions are outlined, emphasizing integrated and biomimetically informed design approaches. Overall, this review aims to define guiding principles that may accelerate the development of durable, regenerative, and clinically translatable tissue-engineered heart valves. We argue that successful TEHV translation requires synchronized control of scaffold anisotropy, immune modulation, and mechanical conditioning rather than incremental material optimization. Full article