Functional oxide surface coatings on ceramic three-dimensional (3D) structures are pivotal for imparting tailored optical, thermal, and chemical functionality to complex architectures in solar energy and other high-end applications. Conventional ceramic 3D printing typically yields a single material, limiting multifunctionality and motivating ceramic composite architectures that integrate complementary properties. Achieving conformal and thermally stable oxide coatings on 3D-printed, high-surface-area ceramic cellular structures is highly desired, though challenging. This study presents a robust strategy for fabricating solar-absorbing CuO and iron-oxide (Fe3O4/Fe2O3) coatings on sintered Al2O3 cellular substrates to achieve high broadband absorptance across the UV-vis-NIR spectrum, which is corroborated by the Monte Carlo Ray Tracing (MCRT) simulation. With these coatings, average solar absorptance is boosted over 80% from 16.72% for bare Al2O3, demonstrating significant optical gains. The broadband absorption is mainly attributed to the strong intrinsic absorption of the oxide coatings, further enhanced by volumetric scattering within porous microstructure. High average absorptance at an operation temperature over 1000 degrees C demonstrates the durability and thermal stability of refractory coatings. Overall, the results demonstrate that controlled thermal processing is an effective route to highly absorbing, thermally stable oxide coatings on 3D-printed ceramic structures for concentrated solar thermal and photocatalytic systems.

The use of near-infrared (NIR) spectroscopy for material classification in recycling facilities has become increasingly prominent due to its rapid, accurate and non-destructive capabilities. However, the high cost of commercial NIR spectrometers – driven largely by their wide spectral range and high resolution – limits widespread adoption, particularly in the smaller-scale decentralized waste segregation stations. This study investigates the feasibility of reduced-range and lower-resolution NIR spectra data for accurate waste classification. To support this investigation, we constructed a dataset by collecting visible-NIR spectra (500-2500 nm) from 11 classes of real household waste materials using a laboratory-grade spectrometer with a 5nm wavelength resolution. Using this dataset, we simulate spectral degradation by systematically reducing the wavelength range and resolution. Hybrid convolutional neural networks (CNN) and support vector machines (SVM) model is trained on both the full and reduced-spec spectra to assess the impact on classification performance. The results indicate that a similar classification accuracy as the full spectral range (98.2%) can be achieved using a narrow spectral range of just 150 nm (with starting wavelengths falling within 1400–1600 nm) at a resolution of 5 nm. Additionally, the analysis shows that targeting two disjoint spectral ranges—each under 200 nm and starting at 1450 nm and 1625 nm—generally yields higher accuracy than using a single continuous range starting at 1600 nm. Overall, we present a promising direction for the development of low-cost NIR sensing systems to support broader adoption.

The integration of two-dimensional (2D) graphene oxide (GO) with zinc-based metal–organic frameworks (MOFs) offers significant potential for environmental remediation. In this study, an in-situ synthesized ZIF-8@GO composite was developed, where ZIF-8 crystals are uniformly dispersed on GO nanosheets to enhance adsorption performance and structural stability. The composite was applied for the removal of malachite green (MG) dye from aqueous solutions, achieving a maximum removal efficiency of 97

We report mode-resolved mechanical evidence that visible-light illumination reversibly modifies the coupled conservative and dissipative response of a nanoscale tip-aqueous junction. Using the passive multimode resonance spectrum of an undriven atomic force microscope cantilever as a local mechanical readout, we observe reversible, near-field-localized changes in resonance frequency and line width upon 532 nm illumination of a deliquesced CaCl2 droplet. Distance-dependent measurements, together with dry-glass and silicone-oil controls, confirm the signal is localized to the aqueous interface's near-field. Analysis of the two lowest eigenmodes rules out purely mass-loaded or conservative origins. Only a model considering both conservative and dissipative contributions reproduces all four modal observables. The extracted conservative perturbation matches a nanoscale capillary force-gradient estimate. The relaxation time scale is consistent with interfacial meniscus kinetics rather than local thermal diffusion. These results establish a nanoscale mechanical framework for probing illuminated aqueous interfaces, constraining the magnitude, dissipative character, and time scale for any proposed mechanism.

Laminated object manufacturing (LOM) is rarely applied in the fabrication of functional structures, as most additive manufacturing methods incorporate nanomaterials within polymer matrices. Carbon nanotube (CNT) buckypapers provide a pathway to translate the exceptional nanoscale properties of CNTs into free-standing microscale sheets. In this study, CNT buckypapers fabricated by vacuum filtration were used as the primary feedstock for sheet lamination. The resulting 3D laminated structures produced by the additive lamination method were evaluated for mechanical, electrical, and thermal behavior to elucidate structure-property relationships associated with layer stacking. Manually stacked CNT structures exhibited significantly higher tensile strength (similar to 12-14 MPa) than LOM-printed structures (similar to 8.5 MPa), while LOM-printed specimens showed considerably higher Young's modulus (up to similar to 830 MPa). In transport properties, electrical conductivity decreased from similar to 75 S/cm for individual buckypaper to 46.29 S/cm and 43.43 S/cm for LOM-printed 3L and 5L structures, respectively. Manually stacked equivalents yielded lower values of 36.69 S/cm (3L) and 27.37 S/cm (5L). Thermal conductivity decreased from 16.73 W/m & centerdot;K for individual buckypaper to 10.83 W/m & centerdot;K and 9.72 W/m & centerdot;K for LOM-printed 3L and 5L structures. Electromechanical testing further showed an increase in electrical conductivity under compressive loading. These results establish LOM as a viable additive manufacturing route for fabricating functional CNT structures.

Ceramic additive manufacturing (AM) enables the production of high-performance components for a wide range of applications, including healthcare, aerospace, and energy. This work aims to examine the microstructural, optical, mechanical, and thermal cycling stability (TCS) of three ceramic oxide structures additively manufactured via fused filament fabrication (FFF). More specifically, ceramic structures made of black-colored zirconia (ZrO2) and white-colored pure alumina (Al2O3) bulk and triply periodic minimal surfaces (TPMS) are fabricated and compared with the previously reported 3D-printed alumina composite (CuO/Al2O3) counterpart for performance evaluation. Overall, ZrO2 demonstrated markedly higher optical absorptance (similar to 89%) compared to Al2O3 (similar to 31%). It also exhibited a significantly higher compressive strength (similar to 1296 MPa) than Al2O3 (similar to 240 MPa). The microstructural analysis of ZrO2 revealed finer grains and better densification than its counterparts, which contributed to its superior mechanical properties. Among the gyroid, diamond, and primitive lattices, the latter exhibited the highest mechanical performance, consistent with the results of finite element analysis (FEA). Our findings highlight the potential of complex-shaped ZrO2 structures for advanced solar energy conversion and other high-performance applications.

Herein, we report a platinum nanozymes (PtNZs)-engineered hydrogel skin patch fabricated via vat photopolymerization technique, specifically digital light processing (DLP) 3D printing, followed by post-printing immersion and in situ chemical reduction of Pt precursors within the printed lattice. This post-fabrication strategy enables the incorporation of PtNZs throughout the three-dimensional hydrogel network while preserving architectural integrity, achieving broad spatial distribution of Pt within the matrix, and confining Pt within the matrix to prevent uncontrolled release. The approach enables quick, cost-effective, and customizable manufacturing of lattice structures with oxidative stress-modulation capability relevant to skin-contact material systems. The physicochemical and morphological analyses reveal successful nanozyme integration, whereas enzyme-mimetic activity is demonstrated by the reduction of methylene blue (MB) in the presence of hydrogen peroxide. The PtNZs-doped hydrogel exhibited strong catalytic activity, achieving similar to 97% MB degradation within 90 min. Biological evaluation further showed that the hydrogel extracts were cytocompatible toward human dermal fibroblasts, with high cell viability (similar to 95-96%). In addition, the extracts exhibited antioxidant activity through both intracellular reactive oxygen species (ROS) suppression (p < 0.0001) and direct free-radical scavenging (similar to 54-57%). The mechanical behavior of the 3D-printed lattices is further investigated in both dry and hydrated situations. Overall, these findings provide a proof-of-concept materials platform that combines nanozyme catalysis and architected hydrogel mechanics, while also demonstrating in vitro cytocompatibility and antioxidant functionality relevant to skin-contact and chronic wound-associated oxidative stress environments.

With the increasing need for sustainable materials, improving biodegradable polymer blends has become critical for environmentally acceptable applications. This study explores the enhancement of polylactic acid (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) blends by functionalizing PHBV to improve their compatibility, thermal properties, and biodegradation performance. DSC, TGA, FTIR, and SEM were used to comprehensively characterize the samples before and after a 44-day composting test. 1H and 13C NMR spectroscopy, complemented by diffusion-ordered spectroscopy (DOSY), were employed to assess the chemical environments and molecular mobility within the blends. Functionalization with 1,1 '-carbonyldiimidazole (CDI) improved miscibility and phase homogeneity, as confirmed by SEM and FTIR analyses. NMR analysis revealed the appearance of new chemical environments associated with CDI-induced interfacial interactions, while DOSY measurements indicated distinct diffusion behaviour between functionalized and non-functionalized blends, reflecting differences in molecular mobility and blend heterogeneity. DSC results showed an increase in PLA crystallinity from 41% in the non-functionalized blend to 47% in the CDI-modified blend. TGA analysis further indicated enhanced thermal stability, with the PLA degradation temperature increasing from 344 degrees C to 362 degrees C. Post-biodegradation analysis showed that the blends retained a more ordered microstructure, with PLA chains displaying enhanced crystallization, most likely due to controlled degradation of the CDI-functionalized PHBV phase. FTIR measurements further supported this selective degradation mechanism and indicated increased degradation resistance. These findings demonstrate that CDI functionalization of PHBV improves compatibility, thermal stability, and biodegradation behaviour in PLA-based systems, highlighting their potential for biodegradable material applications.

Functional oxide surface coatings on ceramic three-dimensional (3D) structures are pivotal for imparting tailored optical, thermal, and chemical functionality to complex architectures in solar energy and other high-end applications. Conventional ceramic 3D printing typically yields a single material, limiting multifunctionality and motivating ceramic composite architectures that integrate complementary properties. Achieving conformal and thermally stable oxide coatings on 3D-printed, high-surface-area ceramic cellular structures is highly desired, though challenging. This study presents a robust strategy for fabricating solar-absorbing CuO and iron-oxide (Fe3O4/Fe2O3) coatings on sintered Al2O3 cellular substrates to achieve high broadband absorptance across the UV–vis–NIR spectrum, which is corroborated by the Monte Carlo Ray Tracing (MCRT) simulation. With these coatings, average solar absorptance is boosted over 80% from 16.72% for bare Al2O3, demonstrating significant optical gains. The broadband absorption is mainly attributed to the strong intrinsic absorption of the oxide coatings, further enhanced by volumetric scattering within porous microstructure. High average absorptance at an operation temperature over 1000 °C demonstrates the durability and thermal stability of refractory coatings. Overall, the results demonstrate that controlled thermal processing is an effective route to highly absorbing, thermally stable oxide coatings on 3D-printed ceramic structures for concentrated solar thermal and photocatalytic systems.

The food supply chain is undergoing critical changes to minimize environmental hazards, such as those associated with packaging, and reduce food waste and loss. One of the critical components of the latter is associated with the high variance in the perishability of individual foodstuffs. Herein, we review the state of the art in smart sensor systems and emphasize the critical role they could play in addressing the mismatch between “batch” based expiry dates and individual food products’ time-dependent responses to spoilage. Following a brief overview of food shelf life and associated legislation, a subsequent section summarizes the development of sensors for monitoring food spoilage. Moreover, this review encompasses sensors for spoilage detection and for monitoring storage quality, including those for measuring gas, pH, humidity, and temperature. A detailed study of their designs, selectivity, range, limit of detection, specific analyte molecules, and active materials is presented, with consideration of the state of the art. Fabrication techniques for sensors are then presented, and the manuscript concludes with an overview of emerging developments and the remaining challenges for their efficient implementation across the food sector. Overall, the article highlights an emerging opportunity for sensor science to have a global impact on a more resilient, safe, and sustainable food supply chain.

The N2V color center is a promising defect for quantum memory applications due to its complex electronic structure from strongly correlated open-shell orbitals. Accurately describing the many-body electronic states, especially the singlet and metastable triplet states, is essential for quantum memory. This work combines Density Functional Theory (DFT) with a two-site Hubbard model to study the N2V center in lonsdaleite/diamond dual structures. The results revealed two possible arrangements of the N2V center, each with Zero Phonon Line (ZPL) values near 2.44-2.45 eV. Hubbard parameter analysis indicates electron delocalization in the dual structure, resulting in a broader luminescence spectrum. Electron-phonon coupling analysis showed stronger coupling and a wider phonon energy range in the lonsdaleite/diamond dual structure than in cubic diamond. Theoretical calculations overestimated electron-phonon coupling, but both theory and experiment show that the N2V center in cubic diamond is a better single-photon emitter than in the dual structure, in line with the Hubbard model's prediction of a broader spectrum for the dual structure.

Nickel-based superalloys, particularly Inconel-718 (IN718), are widely recognized for their excellent resistance to high temperatures, corrosion, and mechanical stress, making them ideal for applications in turbine blades, rocket engines, and high-stress components. This study presents the development of IN718 hybrid composites with enhanced mechanical and thermal properties. Graphene oxide is incorporated to create a carbon-rich environment that facilitates carbide formation within Inconel, while titanium carbonitride (TiCN) is utilized to control grain growth and provide an additional strengthening phase. The composite samples showed a significant improvement in thermal conductivity, from 8.06 to 12.25 W/m & sdot;K, and in indentation hardness (up to 3.57 GPa) and elastic modulus (up to 187 GPa). The enhanced mechanical properties were attributed to the precipitation of fine chromium and niobium carbides within the composites. These improvements make the developed superalloy composites promising candidates for applications in the oil, gas, chemical, and aerospace industries.

Brown diamonds exhibit unique optical properties attributed to structural defects and impurities, including luminescent color centers. This study employs density functional theory (DFT) to model the blue luminescence associated with the N3V color center in a dual cubic diamond/lonsdaleite structure. By analyzing two configurations of the N3V center-C3v and C1h-distinct electronic and geometric features were identified. Calculations of zero-phonon line (ZPL) energies using the delta self-consistent field (Delta-SCF) methods showed that the predicted ZPLs closely matched experimental values for blue luminescent centers at 389 nm and 468 nm. Notably, the C1h configuration exhibited a higher ZPL weight and lower phonon sideband intensity, correlating with the reduced contribution of quasi-localized and bulk vibrational modes. Phonon spectral density analysis further confirmed three primary phonon modes contributing to the luminescence spectrum. These findings suggest an effective role of the N3V defect in brown diamond luminescence.

This study investigates the effects of simulated mechanical recycling cycles on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a biobased and biodegradable polymer, processed by twin-screw extrusion and injection molding. A decrease in melt flow index and an increase in melt viscosity and molar mass after the first cycle indicate branching and recombination reactions altering the polymer structure. Fourier-transform infrared spectroscopy reveals pronounced degradation in injection-molded samples, with carbonyl loss, while extruded samples show limited spectral changes, suggesting different degradation mechanisms. After the first injection cycle, thermal stability improves temporarily, with a higher degradation temperature than the neat polymer, but declines in subsequent cycles. Extruded samples show greater stability, with minimal variation in degradation temperature. Mechanically, extruded samples develop higher stiffness, indicated by increased Young's modulus, while stress at break remains stable across both methods. Impact toughness decreases after the first cycle, though injection-molded samples maintain higher impact resistance. Biodegradation is faster in injection-molded samples due to lower crystallinity and greater molecular mobility. Differential scanning calorimetry of degraded samples reveals two melting points, suggesting chain rearrangement and phase separation during microbial attack. The study highlights how processing methods influence PHBV's structure, stability, mechanical performance, and biodegradability, offering valuable insights for optimizing its recyclability and functionality in sustainable material applications.

Lonsdaleite is a carbon allotrope and metastable form of diamond that demonstrates superior mechanical properties over cubic diamond. Here, we report the results of density functional theory (DFT) and molecular dynamics (MD) studies of neutral and negative nitrogen vacancy (NV) centers in lonsdaleite. Interestingly, the neutral (NV0) and negative (NV-1) nitrogen vacancy centers in lonsdaleite display a remarkable splitting between the two degenerate e(x) and e(y) excited states nearly around similar to 0.5 eV for NV0 and 0.2 eV for NV-1, respectively. The thermal stability, dynamic stability, band structure, density of states, and optical properties are computed. DFT and MD calculations reveal that the geometrical structure of the NV center in lonsdaleite is both thermally and dynamically stable. In addition, the findings show that NV0 and NV-1 centers in lonsdaleite demonstrate splitting in the zero-phonon line (ZPL) due to symmetry reduction from C-3v to C-1h with respect to the NV center in cubic diamond. Furthermore, the results indicate that ZPL falls around similar to 1.76 and 2.25 eV for NV0, whereas it lies around 1.91 and 2.19 eV for NV-1.

Cholesterol sensing is essential for the early detection of several diseases such as hypercholesterolemia, atherosclerosis, and cardiovascular disorders. To address the limitations of enzyme-based methods, this paper proposes a novel Metal Organic Framework (MOF)-based spectrophotometric platform for cholesterol detection. Iron-based MOF (Fe-BTC) is introduced as a novel, peroxidase mimic nanozyme for cholesterol detection. Characterization studies run on Fe-BTC, including Fourier transform infrared spectroscopy, X-ray diffraction, and zeta potential, revealed its stable, amorphous nature and potential peroxidase activity due to Fe centers. Parametric studies including pH, time, temperature, and reagent concentrations were performed to determine operating conditions for H2O2 and cholesterol detection. Mechanistic studies demonstrated biosensor operation via OH· radical formation by Fe-BTC. The present biosensor achieved a cholesterol limit of detection (LOD) of 2.91 µM and 2.88 µM at 25 °C and 37 °C cholesterol incubation, respectively, with a linear detection range of 6.56–78.75 µM at both temperatures. The biosensor had good selectivity to cholesterol in the presence of interfering analytes, including glycine, uric acid, glucose, and NaCl. Overall, our novel Fe-BTC-based biosensor demonstrated comparable performance to nanomaterial-based cholesterol sensors reported in the literature, with a simpler, cheaper, and scalable design, and shows great promise for cholesterol detection via spectrophotometric methods.

Synthetic dyes released by the textile and related industries are a major source of water pollution due to their persistence, toxicity, and resistance to conventional treatment methods The development of sustainable and efficient biosorbents therefore represents a key challenge in wastewater treatment. In this study, dried Posidonia Oceanica (P.O) biomass was used for the first time in the microwave-assisted synthesis of hybrid materials functionalized with copper (1 %, 2 %, and 4 % Cu2+), offering a rapid, energy-efficient, and solvent-free alternative to conventional methods. This technique enhances chemical yield and reaction control while minimizing environmental impact. The raw and modified P.O fibers were characterized using zero point of charge (pHpzc) and Boehm titration to determine surface acidity/basicity. Further structural and morphological analyses were conducted using infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS), confirming the formation of Cu–OH, Cu–O–C, and Cu(COOH)2 bonds and an increase in basic surface sites. The materials' adsorption performance was assessed by removing methyl orange (MO) from aqueous solutions. Biosorption capacity increased from 0.768 mg g−1 for raw P.O to 0.981 mg g−1 for P.O-4 % Cu2+. Important factors influencing adsorption were examined. Prewashing with 0.01 M EDTA reduced NaCl interference, thereby enhancing MO removal. Increasing the adsorbent mass improved dye uptake; while higher temperature slightly improved adsorption, indicating a slightly endothermic process. Kinetic modeling using pseudo-first-order, pseudo-second-order, and Brouers–Sotolongo (n = 2) models indicated that the Brouers–Sotolongo model best described the process, with improved retention rates and homogeneity (α = 1; ζc = 2.51 min). Recyclability tests demonstrated that P.O-4 % Cu2+ retained 92 % of its adsorption capacity after three cycles when regenerated with HCl + NaCl, highlighting its potential for reuse. These results demonstrate that microwave-assisted Cu2+ modification significantly enhances the biosorption properties of P.O fibers, making them promising, sustainable biosorbents for dye removal in wastewater treatment applications.

Additive manufacturing (AM) of three-dimensional (3D) compact ceramic structures has extensive applications across various sectors, including energy, water, aerospace, and communications. However, several challenges, such as a limited selection of printable materials, low 3D printing resolution and a lack of multifunctionality hinder its widespread use. This work proposes a facile approach to infiltrate copper oxide (CuO) into a 3D-printed alumina (Al2O3) structure for enhancing the optical performance of Al2O3 ceramics. Various triply periodic minimal surface (TPMS)-based Al2O3 structures are fabricated with both vat photopolymerization and material extrusion techniques, specifically high-resolution projection stereolithography and cost-effective fused deposition modeling. Molten CuO spreads over the surface of Al2O3 preform volumetrically along with sintering and penetrates through the intergranular pores of Al2O3 driven by capillary force, which eventually results in a uniform distribution of CuO crystals within 3D porous Al2O3 structures. The in-situ mobilization and capillary infiltration of molten CuO among Al2O3 particles of different sizes is investigated to reveal the microstructure, optical-mechanical properties and thermal stability of CuO/Al2O3 composite structures. Owing to the recrystallization of CuO around the Al2O3 particles, the light absorptance of 3D composite structures is proportional to the CuO concentration and significantly enhanced in the wavelength range 250-2000 nm for solar applications. This AM approach for ceramic composite opens new avenues to functional 3D component manufacturing for a large variety of cutting-edge applications.

Achieving high-quality molybdenum disulfide (MoS2) thin films through scalable and uniform solution-based deposition techniques remains a critical challenge for optoelectronic and nanoelectronic applications. This study presents a simplified yet highly effective modified interfacial assembly method utilizing a hexane-water interface, which enables the deposition of a tightly packed, uniform MoS2 thin film. Scanning electron microscopy analysis reveal substantial improvement in surface coverage (approximate to 90%), underscoring the enhanced efficiency of the process. Optical characterization of the exfoliated MoS2 flakes reveal an indirect bandgap of 1.63 eV, confirming the presence of multilayer MoS2, which is optimal for charge transport layer applications. Electrical measurements demonstrate a direct current conductivity of 0.898 x 10-6 S cm-1, suitable for device integration. Importantly, an organic solar cell incorporating the ultrathin MoS2 film as an electron transport layer is demonstrated.

Massive energy is consumed to cool buildings for comfortable life in hot climates due to indoor air-conditioning, which necessitates the passive daytime radiative cooling of buildings. Given the high ambient temperature, it is essential to increase the thermal resistance of building walls through paints and enhance their durability to dust and aerosol contamination. In this work, a multifunctional composite paint, mainly consisting of inorganic pigments and mesoporous silica aerogel (SA), is proposed for passive radiative cooling, low thermal conductivity, and surface self-cleaning. In comparison with ordinary paint, the SA microparticles-infused composite paint can enhance the reflectance (ρVIS-NIR) to the solar irradiance by up to 15% in the visible and near-infrared ranges (0.3–2.5 μm). It also maintains the radiative cooling property with about 0.96 emissivity (εLWIR) in the atmospheric transparency windows (8–13 μm) for thermal radiation to dissipate into the cold outer space. Even after long-term outdoor exposure to harsh environmental conditions, SA-infused white paint can still maintain its spectral and wetting properties, achieving daytime cooling with 7.4 °C lower than the ambient temperature. Moreover, the SA infusion enables the paint to reduce the thermal conductivity by 50% and provide much better thermal insulation, while SA renders the paint surface hydrophobic and self-cleaning.