Search Results (876)

Eggshell waste represents an underutilized biogenic resource, rich in calcium carbonate and organic components, whose increasing generation poses significant environmental and economic challenges. It is estimated that more than 8 million tons of eggshells are produced worldwide annually, most of which are disposed of in landfills, leading to landfill overload and increased waste management costs. In this context, the main objective of this study was to develop and compare three processing routes for converting calcium carbonate derived from eggshell waste into calcium acetate, using commercial vinegar (4–5% acetic acid) as a low-cost, sustainable acid source. The proposed routes were systematically evaluated based on processing efficiency, product characteristics, and operational simplicity. The materials obtained were characterized by X-ray fluorescence, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTG), X-ray photoelectron spectroscopy (XPS), particle size analysis, and zeta potential measurements. The results indicated that the eggshells contained approximately 95.39% calcium, confirming their suitability as an efficient calcium precursor. Among the routes evaluated, the process using a spherical condenser under reflux at 90 °C showed superior performance, achieving shorter reaction times and maintaining comparable yields of membrane byproducts compared to the other methods. This approach differs from conventional routes by eliminating the need for high-purity reagents, reducing processing time, and using exclusively food-grade acetic acid, thus increasing sustainability and cost-effectiveness. Morphological, chemical, and thermal analyses confirmed the quality and stability of the synthesized calcium acetate. In general, these results demonstrate that eggshell waste can be efficiently valorized into calcium acetate through a scalable, straightforward process, thereby reducing landfill disposal and supporting circular economy strategies, with potential applications in the production of calcium-based biomaterials. Full article

Time-varying or temporal metamaterials and metasurfaces, in which electromagnetic parameters are deliberately modulated in time, have emerged as a powerful route to engineer wave–matter interaction beyond what is possible in static media. By enabling the controlled exchange of energy and momentum with the fields, they underpin magnet-free nonreciprocity, low-loss frequency conversion, temporal impedance matching beyond Bode-Fano limit, and unconventional parametric gain and noise control. This survey provides a coherent framework that unifies the main theoretical and experimental developments in the area, from early analyses of velocity-modulated dielectrics to recent demonstrations of temporal photonic crystals, non-Foster temporal boundaries, and spatiotemporally driven metasurfaces relevant to nanophotonic platforms. We systematically compare time-varying permittivity, joint $\epsilon$-$\mu$ modulation, time-varying conductivity, plasmas, and circuit-equivalent implementations, including stochastic and rapidly sign-switching regimes, and relate them to acoustic and quantum analogs using common figures of merit, such as conversion efficiency, isolation versus insertion loss, modulation depth and speed, dynamic range, and stability. Our work concludes by outlining key challenges, loss and pump efficiency, high-speed modulation at the nanoscale, dispersion engineering for broadband operation, and fair benchmarking, which must be addressed for robust, integrable temporal metasurfaces. Full article

This study identifies the technological signature of ancient and alternative “Chu” and “Kriab” gold glass mosaic mirrors from Thailand. Although these mirrors play an important role in Thai decorative heritage, their production routes and interfacial chemistry at the lead-to-glass interface have remained unclear. A survey of 154 sites across Thailand shows mosaic glass was widely distributed and likely produced during the Ayutthaya period (~300 years ago). Portable X-Ray Fluorescence (pXRF), Wavelength-Dispersive XRF (WD-XRF), scanning electron microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS) were used to examine the material properties of observed Chu mirrors. Most samples can be classified as a mixed lead–alkaline glass type, with a PbO content ranging from 4.28 to 48.17 wt%. Their yellow tone is controlled by iron and manganese redox states. Chemical and physical analyses distinguish between Chu from the northern part of Thailand and Kriab from the central part of Thailand, which share a silica source but rely on different fluxes, pointing to different glass workshops. Crucially, XPS depth profiling reveals a well-defined interfacial reaction zone extending to approximately 6 nm in the ancient mirrors, predominantly characterized by disordered, chain-like Pb–O–Pb linkages. These polymeric structures enable a “chemical bridging” mechanism that effectively accommodates interfacial strain arising from thermal expansion mismatch, thereby ensuring exceptional long-term adhesion. Furthermore, the depth-dependent distribution of hydrated lead species and the emergence of photoelectron energy-loss features beyond ~6 nm distinguish the superior metallic integrity of the ancient coatings from the alternative reproductions. This distinct stratification confirms that ancient artisans achieved a sophisticated balance between a chemically bonded interface and a coherent metallic bulk. These findings offer significant insights into the ingenuity of ancient Thai artisans, providing a scientific foundation for the conservation, restoration, and replication of these culturally significant artifacts. Full article

The study of Palaearctic enchytraeid taxonomic richness revealed the limitations of applying morphological identification methods to certain species of the genus Cognettia. The use of molecular approaches enabled the identification of individuals belonging to C. chlorophila among immature and fragmented enchytraeids that had initially been identified morphologically as C. sphagnetorum s.l. These findings substantially extend the known distribution range of C. chlorophila eastward. Reliable distribution data for C. chlorophila and C. sphagnetorum s.s., obtained through genetic analysis, complement existing evidence of their coexistence in shared habitats and highlight questions concerning their biotopic preferences. It is hypothesized that the relatively low level of genetic diversity in these species is associated with potential postglacial dispersal routes of C. sphagnetorum s.l. from Scandinavian refugia and with species-specific biological characteristics. Full article

This study investigates the interface between cement hydration, low-field NMR relaxometry, and the incorporation of carbon-based fillers into cementitious materials. The objective is to provide NMR-based insights into how carbon black (CB) and an acrylic superplasticizer (SP) influence cement hydration and the resulting microstructural evolution. CB was integrated into white Portland cement (WPC) using both wet and dry mixing approaches, with water content and SP dosage varied independently. First, water-based “inks” containing different SP/CB weight ratios were prepared and evaluated through dynamic light scattering (DLS) and ζ-potential measurements to assess colloidal stability and dispersibility. For the wet-mixing route, an in situ NMR experiment was performed to monitor the progressive incorporation of carbon ink into cement pastes while increasing the water content. The ability to distinguish ink-related signals from those originating from the cement paste represents a promising step toward non-destructive assessments of carbon dispersion in fresh pastes. Separately, ex situ NMR measurements were performed on samples extracted from dry-mixed pastes with various SP dosages. These experiments mark the SP-induced delay in hydration and the refinement of the pore network that is also associated with improved particle dispersion. Complementary optical microscopy (OM) and ultrasonic pulse velocity (UPV) measurements on hardened samples corroborate the NMR findings. Full article

The performance of conventional precipitation-strengthened copper alloys drastically degrades at temperatures exceeding 500 °C, hindering their application under extreme conditions like those in nuclear fusion reactors. Oxide dispersion–strengthened copper (ODS–Cu) alloy surmounts these constraints by incorporating thermally stable, nanoscale oxide dispersoids that simultaneously confer strengthening, microstructural stabilization, and enhanced irradiation tolerance, while preserving high thermal conductivity. This review comprehensively examines the state of the art in ODS–Cu alloy from a “processing–microstructure–property” perspective. We critically assess established and emerging fabrication routes, including internal oxidation, mechanical alloying, wet chemical synthesis, reactive spray deposition, and additive manufacturing, to evaluate their efficacy in achieving uniform dispersions of coherent/semi-coherent nano-oxides at engineering-relevant scales. The underlying strengthening mechanisms and performance trade-offs are quantitatively analyzed. The review also outlines strategies for joining and manufacturing complex components, highlights key gaps in metrology and reproducibility, and proposes a roadmap for research and standardization to accelerate industrial deployment in plasma-facing components. Full article

Polymer composites reinforced with nanofillers, synthetic fibers, and inorganic fillers have progressed rapidly, yet recent advances remain fragmented across filler-specific studies and often lack unified mechanistic interpretation. This review addresses this gap by presenting an interphase-centric, mechanism-driven framework linking processing routes, dispersion and functionalization requirements, interphase formation, and the resulting structure–property relationships. Representative quantitative datasets and mechanistic schematics are integrated to rationalize nonlinear mechanical reinforcement, percolation-controlled electrical/thermal transport, and thermal stabilization and barrier effects across major filler families. The review highlights how reinforcement efficiency is governed primarily by interfacial adhesion, filler connectivity, and processing-induced microstructural evolution rather than filler loading alone. Key challenges limiting scalability are critically discussed, including dispersion reproducibility, viscosity and processability constraints, interphase durability, and recycling compatibility. Finally, mechanism-based design rules and future outlook directions are provided to guide the development of high-performance, multifunctional, and sustainability-oriented polymer composite systems. Full article

Hydrometallurgical pretreatment of pyrite-bearing concentrates and tailings by hydrothermal interaction with Cu(II) solutions is a promising route for chemical beneficiation and mitigation of acid mine drainage but is limited by passivation caused by elemental sulfur and secondary copper sulfides. Here, the effect of sodium lignosulfonate (SLS) on the hydrothermal reaction between natural pyrite and CuSO₄ in H₂SO₄ media at 180–220 °C was studied at [H₂SO₄]₀ = 10–30 g/dm³, [Cu]₀ = 6–24 g/dm³, and [SLS]₀ = 0–1.0 g/dm³. Process efficiency was evaluated by Fe extraction into solution and Cu precipitation on the solid phase, and products were characterized by XRD and SEM/EDS. SLS markedly intensified pyrite conversion: at 200 °C and 120 min, Fe extraction increased from 14 to 26% and Cu precipitation from 5 to 23%, while at 220 °C, Fe extraction reached 33.4% and Cu precipitation 26.8%. XRD confirmed the sequential transformation CuS → Cu_1.8S. SEM/EDS showed that SLS converts localized nucleation of Cu_xS on defect sites into the formation of a fine, loosely packed, and well-dispersed copper sulfide phase. The results demonstrate that lignosulfonate surfactants efficiently suppress passivation and enhance mass transfer, providing a basis for intensifying hydrothermal pretreatment of pyrite-bearing industrial materials. Full article

Accurate information regarding species boundaries is essential for ecological research and conservation planning. This information is particularly difficult to obtain but essential for cryptic amphibian species. The distribution and potential dispersal corridors of two cryptic salamander species, the Korean clawed (Onychodactylus koreanus) and the Yangsan clawed (O. sillanus) salamanders, were investigated using integrated approaches for high-resolution species distribution modeling (SDM), genetic species identification, and habitat connectivity analysis. The SDM results showed high habitat suitability in mid- and high-mountainous areas, but very low suitability in riverine areas for both species. Genetic species identification of the 25 populations delimited the distribution boundary between the two species along the Nakdong and Geumho rivers. Dispersal corridors of the two species commonly involved a detour around the major rivers and produced only one possible dispersal route, where both species moved into the opposite species’ habitat along the east side of the mountainous areas of the Geumho River. The findings not only clarify the distribution range of two cryptic Onychodactylus species in the Republic of Korea but also highlight the importance of the unique dispersal route for studying species interactions and maintaining ecological connectivity. Full article

Based upon density functional theory (DFT) calculations, we present the basic electronic structure of CuPb₉(PO₄)₆O (Cu-doped lead apatite, aka LK-99), in two scenarios: (1) where the structure is constrained to the P3 symmetry and (2) where no symmetry is imposed. At the DFT level, the former is predicted to be metallic while the latter is found to be a charge-transfer insulator. In both cases the filling of these states is nominally $d^9$, consistent with the standard Cu²⁺ valence state, and Cu with a local magnetic moment of order 0.7 μ_B. In the metallic case we find these states to be unusually flat (∼0.2 eV dispersion), giving a very high density of electronic states (DOS) at the Fermi level that we argue can be a host for novel electronic physics. The flatness of the bands is the likely origin of symmetry-lowering gapping possibilities that would remove the spectral weight from $E_F$. Motivated by some initial experimental observations of metallic or semiconducting behavior, we propose that disorder (likely structural) is responsible for closing the gap. Here, we consider a variety of possibilities that could possibly close the charge-transfer gap but limit consideration to kinds of disorder that preserve electron count. Of the possible kinds we considered (spin disorder, O populating vacancy sites, and Cu on less energetically favorable Pb sites), the local Cu moment, and consequently the charge-transfer gap, remains robust. We conclude that disorder responsible for metallic behavior entails some kind of doping where the electron count changes. Further, we claim that the emergence of the flat bands should be due to weak wave function overlap between the orbitals on Cu and O sites, owing to the directional character of the constituent orbitals. Therefore, finding an appropriate host structure for minimizing hybridization between Cu and O while allowing them to still weakly interact should be a promising route for generating flat bands at $E_F$ which can lead to interesting electronic phenomena, regardless of whether LK-99 is a superconductor. Full article

Photocatalytic reduction of CO₂ into value-added chemicals offers a sustainable route to mitigate greenhouse gas emissions while producing renewable fuels. However, conventional TiO₂-based systems suffer from limited visible-light activity and inefficient reactor configurations. Here, we developed electrospun polyacrylonitrile (PAN) membranes embedded with TiO₂-Cu₂O heterojunction nanoparticles and integrated them into a custom crossflow photocatalytic membrane reactor. The reactor employed bifacial illumination using a solar simulator (front) and a xenon/mercury lamp (back), each calibrated to 1 Sun (100 mW·cm⁻²). Membrane morphology was characterized by SEM, and chemical composition was confirmed by XPS. Photocatalytic performance was evaluated in CO₂-saturated 0.5 M potassium bicarbonate solution under continuous flow. The PAN/ TiO₂-Cu₂O membrane exhibited a methanol production rate of approximately 300 μmol·g⁻¹·h⁻¹ under dual-light illumination, outperforming single illumination, PAN-TiO₂, and PAN controls. Enhanced activity is attributed to extended visible-light absorption, improved charge separation at the TiO₂-Cu₂O heterojunction, and optimized photon flux through bifacial illumination. The electrospun architecture provided high surface area and porosity, facilitating CO₂ adsorption and catalyst dispersion. Combining heterojunction engineering with bifacial reactor design significantly improves solar-driven CO₂ conversion. This approach offers a scalable pathway for integrating photocatalysis and membrane technology into sustainable fuel synthesis. Full article

A sustainable circular pathway was developed for poly(ethylene terephthalate) (PET) nanocomposites through a catalyst-driven polymerization and depolymerization process. In this study, calcium dodecylbenzene sulfonate with n-butyl alcohol modified ZnAl layered double hydroxides (LDHs) were utilized as bifunctional catalysts to synthesize highly exfoliated PET/LDH nanocomposites via in situ polycondensation of bis(2-hydroxyethyl) terephthalate (BHET). The organic modification of LDHs expanded interlayer spacing, improved interfacial compatibility, and promoted uniform dispersion, leading to enhanced mechanical, thermal, and barrier properties. In the second stage, the pristine LDH catalyst efficiently depolymerized the prepared PET/LDH nanocomposites back into BHET through glycolysis, completing a closed-loop BHET-to-BHET cycle. This integrated strategy demonstrates the reversible catalytic functionality of LDHs in both polymerization and depolymerization, reducing metal contamination and energy demand. The proposed approach represents a sustainable route for designing recyclable high-performance PET nanocomposites aligned with the principles of green chemistry and circular material systems. Full article

Thermochromic smart windows are a promising technology to reduce energy consumption in buildings, particularly in tropical regions where cooling demands are high. Vanadium dioxide (VO₂) is the most studied thermochromic material due to its reversible semiconductor-to-metal transition near 68 °C. Conventional synthesis routes require long reaction times and post-annealing steps. In this work, we report a rapid hydrothermal synthesis of monoclinic VO₂(M) and tungsten-doped VO₂(M) powders obtained within only 6 h at 270 °C, using vanadyl sulfate as precursor and controlled precipitation at pH ≈ 8.5. Differential scanning calorimetry confirmed the reversible transition at 59 °C for the undoped VO₂, with a hysteresis of 18 °C, while tungsten doping reduced the transition temperature by ~17 °C per wt.% of W. X-ray diffraction verified the monoclinic phase with minor traces of VO₂(B), a non-thermochromic polymorph of VO₂, and microstructural analysis revealed crystallite sizes below 35 nm. Electron microscopy and dynamic light scattering confirmed particle sizes suitable for dispersion in polymeric matrices. This approach significantly reduces synthesis time compared to typical hydrothermal methods requiring 20–48 h and avoids further annealing. The resulting powders provide a low-cost and scalable route for fabricating thermochromic coatings with transition temperatures closer to ambient conditions, making them relevant for smart-window applications in tropical climates, where lower transition temperatures are generally regarded as beneficial. Full article

In struggling against invasive species ravaging riverscape ecosystems, gaps in dispersal pathway knowledge and fragmented approaches across scales have long stalled effective riparian management worldwide. To reduce these limitations and enhance invasion management strategies, selecting appropriate alien species as models for in-depth pathway analysis is essential. Alternanthera philoxeroides (Mart.) Griseb. (alligator weed) emerges as an exemplary model species, boasting an invasion record of around 120 years spanning five continents worldwide, supported by genetic evidence of repeated introductions. In addition, the clonal reproduction of A. philoxeroides supports swift establishment, while its amphibious versatility allows occupation of varied riparian environments, with spread driven by natural water-mediated dispersal (hydrochory) and human-related vectors at multiple scales. Thus, leveraging A. philoxeroides, this review proposes a comprehensive multi-scale framework, which integrates monitoring with remote sensing, environmental DNA, Internet of Things, and crowdsourcing for real-time detection. Also, the framework can further integrate, e.g., MaxEnt (Maximum Entropy Model) for climatic suitability and mechanistic simulations of hydrodynamics and human-mediated dispersal to forecast invasion risks. Furthermore, decision-support systems developed from the framework can optimize controls like herbicides and biocontrol, managing uncertainties adaptively. At the global scale, the dispersal paradigm can employ AI-driven knowledge graphs for genetic attribution, multilayer networks, and causal inference to trace pathways and identify disruptions. Based on the premise that our multi-scale framework can bridge invasion ecology with riverscape management using A. philoxeroides as a model, we contend that the implementation of the proposed framework tackles core challenges, such as sampling biases, shifting environmental dynamics, eco–evolutionary interactions using stratified sampling, and adaptive online algorithms. This methodology is purposed to offer scalable tools for other aquatic invasives, evolving management from reactive measures to proactive, network-based approaches that effectively interrupt dispersal routes. Full article

Background: Liposomes are attractive topical carriers, yet translating laboratory fabrication to scalable, well-controlled processes remains challenging. Objectives: We compared three manufacturing methods for diclofenac-loaded liposomes: probe sonication, microfluidic mixing, and a high-turbulence microreactor, under a Quality-by-Design framework. Methods: Differential scanning calorimetry (DSC) was used to define a processing-relevant liquid-crystalline temperature window for the lipid excipients. For sonication scale-up, a Plackett-Burman screening design identified key process factors and supported an energy-density (W·s·L⁻¹) control approach. For microfluidics, the effects of flow-rate ratio (FRR) and total flow rate (TFR) were mapped and optimized using a desirability function. Microreactor trials were performed at elevated throughput. Residual ethanol during post-processing was monitored at-line by Raman spectroscopy calibrated against gas chromatography (GC). Particle size and dispersity were measured by DLS and morphology assessed by cryo-TEM. Results: DSC supported a 70–85 °C processing window. Sonication scale-up using an energy-density target (~11,000 W·s·L⁻¹) reproduced lab-scale quality at 8 L (Z-average ~87–92 nm; PDI 0.16–0.23; %EE 86–94%). Microfluidics optimization selected FRR 3:1/TFR 4 mL·min⁻¹, yielding ~64 nm liposomes with PDI ~0.13 and %EE ~93%. The microreactor achieved ~50 nm liposomes with %EE ~95% at 50 mL·min⁻¹. Cryo-TEM corroborated size trends and showed no evident aggregates. Conclusions: All three routes met topical CQAs (~50–100 nm; PDI ≤ 0.30; high %EE). Method selection should be guided by target size/dispersity and operational constraints: sonication enables energy-based scale-up, microfluidics offers precise size control, and microreactors provide higher throughput. Full article