Search Results (6,296)

The construction sector’s substantial contribution to global energy consumption and CO₂ emissions motivates the development of bio-based alternatives to fossil-derived rigid polyurethane (PUR) foam cores in structural sandwich panels. This study presents a comprehensive comparison of plywood sandwich panels manufactured with a rigid PUR foam containing a fast pyrolysis bio-oil (FPBO)-derived sugar polyol diluted with triethyl phosphate and panels of identical topology produced with a commercial reference PUR foam. In the bio-based formulation, a fraction of the sorbitol-based polyether polyol was replaced with the FPBO-derived sugar polyol. Both systems were characterized at the foam and panel levels for cellular microstructure, skeletal and envelope density, thermogravimetric stability, flammability, color, thermal conductivity and heat capacity, internal bond strength, compressive properties, and normal-incidence sound absorption and transmission loss. The newly developed foam exhibited similar skeletal density and porosity to the reference, comparable thermogravimetric stability with a slightly higher char residue, and lower thermal conductivity across the tested temperature range. Mechanical properties, including compressive strength, compressive modulus, and internal bond strength, showed minor reduction but remained within a comparable range. A distinct color change was observed, attributable to the presence of chromophoric constituents of the FPBO fraction. Overall, the results indicate that partial substitution of the fossil polyol with an FPBO-derived sugar polyol is technically feasible, yielding materials with comparable thermal, mechanical, or acoustic performance. No consistent performance advantage of either system was observed across the evaluated properties. The results support the potential of pyrolysis-derived bio-polyols for use in sustainable structural insulation products. Full article

Tungsten trioxide (WO₃) is the most widely studied cathodic electrochromic (EC) material, serving as the core component of energy-efficient smart windows, displays, and optical modulation devices. Post-deposition annealing, as a critical post-processing technique, precisely regulates the microstructure, crystallinity, oxygen vacancy concentration, and electronic structure of WO₃ thin films, thereby directly determining their EC performance. This review summarizes the research progress of annealing effects on WO₃ films, focusing on the synergistic regulation of annealing temperature, atmosphere, and dwell time. It elaborates on the fundamental EC mechanisms of amorphous and crystalline WO₃, including polaron hopping and free-electron Drude behavior, and analyzes the influence of different deposition methods (magnetron sputtering, sol–gel, electrodeposition, etc.) on the annealing response of films. The optimal annealing windows for balancing optical modulation, coloration efficiency, switching speed, and cycling stability are clarified: moderate temperatures (200–350 °C) and inert/air atmospheres yield mixed amorphous–nanocrystalline structures with optimal oxygen vacancy content. Current challenges such as the inherent contrast–stability trade-off and thermal budget limitations of flexible substrates are discussed, and future directions including spatially resolved annealing, interface co-design, and machine learning-assisted optimization are prospected. This work provides a theoretical reference and process guidance for the development of high-performance WO₃-based EC devices. Full article

Carboxymethyl cellulose (CMC)-based materials are widely studied for functional materials and porous platform applications, yet their stability usually requires energy-intensive thermal curing or toxic chemical crosslinkers, which limit process sustainability. In this work, we present a more sustainable approach for the preparation of CMC-based foams using deep eutectic solvents (DES) as multifunctional structuring agents. CMC hydrogels were prepared with different DES at room temperature, followed by freeze-drying to obtain foams. Among the tested DES, choline chloride:oxalic acid (1:1) combined with glycerol produced foams with the most favorable properties, including high water uptake (288.24 ± 3.02% after 1 h) and water stability for 28 days. Morphological analysis revealed a homogeneous and interconnected porous network (32.2 ± 13.3 µm), while compression tests demonstrated good mechanical recovery (93.29 ± 3.12% over 10 cycles). Fourier transform infrared spectroscopy suggests interactions between CMC and DES, especially hydrogen bonds. The foams exhibited pH-dependent behavior, with limited resveratrol release under acidic conditions (22.2 ± 4.0% after 24 h), with significant release at pH 7.4 (85.30 ± 5.75%) and total release at pH 13.0. Drug release kinetics suggest a diffusion-controlled mechanism under acidic pH, transitioning to anomalous transport at higher pH values. This study demonstrates that DES can be used to prepare CMC-based foams, providing a more sustainable route to porous materials. Although biological validation is needed to confirm therapeutic safety, this study provides an initial physicochemical basis for using these matrices as tunable and stimuli-responsive porous materials. Full article

Microencapsulated phase change material (MPCM)-modified cement composites have attracted increasing attention for energy-efficient buildings and thermal energy storage applications. Accurate prediction of thermal conductivity is essential for optimizing thermal management performance. However, quantitative understanding of the multiscale heat transfer mechanisms in MPCM-modified cement composites remains relatively limited. In this study, the thermal transport behavior of MPCM-modified cement composites was investigated through experimental characterization and multiscale theoretical modeling. A micro–macro combinatorial accumulation approach was developed based on representative volume element (RVE) construction and cumulative thermal interactions to characterize hierarchical heat transfer mechanisms within the composite system. The proposed model enables quantitative prediction of thermal conductivity for inclusions with different geometries and accumulation states. The results revealed that the proposed MMCA model successfully captured the multiscale evolution of thermal conductivity by considering cumulative RVE effects and inclusion geometrical characteristics. The effective thermal conductivity decreased from 0.802 to 0.519 W/(m·K) as the MPCM volume fraction increased from 0 to 0.217, corresponding to a reduction of approximately 35.3%. Furthermore, the accumulation of RVEs exhibited a rapid reduction followed by stabilization of thermal conductivity, revealing the scale-dependent heat transfer behavior induced by hierarchical inclusion interactions. The main contribution of this work is the establishment of a physics-based multiscale framework that quantitatively links MPCM inclusion characteristics, cumulative thermal interactions, and macroscopic thermal conductivity, providing new insights into the micro-to-macro heat transfer mechanisms of PCM-modified cement composites. This study offers theoretical support for the multiscale design and thermal performance optimization of PCM-modified energy-functional cementitious materials. Full article

Biopolymer-based porous materials are attracting increasing interest as sustainable alternatives to conventional thermal insulation foams; however, achieving low thermal conductivity together with adequate mechanical performance and fire response remains challenging. Building on previous formulation screening, this study investigates alginate-expanded perlite xerogel foams modified with chitosan and glycerol for thermal insulation applications. Foams were prepared via in situ CO₂ foaming and Ca²⁺ crosslinking, followed by mild oven drying. The effects of expanded perlite (9–12%), glycerol (0–10%), and chitosan (0–1%) were systematically investigated. All formulations exhibited low thermal conductivity (0.0467–0.0525 W m⁻¹ K⁻¹) and UL-94 V-0 self-extinguishing behavior. Incorporation of dispersed chitosan significantly enhanced compressive strength, reaching 263 kPa at 10% strain, within the range of commercial polymer foams. Image analysis and SEM showed that chitosan suppressed bubble coalescence, reduced large-pore fractions, and improved particle coverage, yielding structurally coherent matrices. Glycerol primarily acted as a plasticizer, improving the dimensional stability, but contributing less to pore refinement. The developed foams combine competitive thermal insulation performance, self-extinguishing behavior, and mechanical properties suitable for self-supporting insulation applications through a simple, water-based manufacturing route, highlighting their potential as sustainable alternatives to conventional fossil-based insulation materials for building applications. Full article

Climate change and population growth are intensifying global food security challenges by reducing agricultural productivity and increasing reliance on fertilizers. In this context, developing sustainable and economically efficient agricultural solutions becomes essential. The study presents the synthesis of an interpenetrating polymer network (IPN) of hydrogels by combining bacterial cellulose (BC) with poly(acrylic acid) crosslinked with N, N-methylene-bis-acrylamide (PAA–co–MBA) via free radical copolymerization. To explore their potential as bioactive compound carriers, an ethanolic hydroalcoholic phytoextract (EHP) obtained from Hypericum perforatum L. and Melissa officinalis L. was directly encapsulated within the IPN hydrogels. The EHP is valued for its rich bioactive profile and antifungal, antimycobacterial, and antioxidant properties. The results of rheology measurements and thermal gravimetric analysis (TGA) revealed that incorporating BC into the IPN hydrogels significantly enhanced the mechanical stiffness, thermal resistance, and overall stability of the resulting IPN structures. Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) confirmed the structural organization and the porosity of the developed composite, as well as the successful fabrication of IPN hydrogels in the EHP medium. Under optimal conditions, the IPN hydrogels exhibited a reduced swelling capacity, thereby slowing the diffusion of the bioactive agents, reducing the application frequency, and enhancing the utilization efficiency. Taken together with the controlled-release performance, these findings demonstrate the potential of BC (PAA-co-MBA) IPN hydrogels as biodegradable and sustainable carrier systems for controlled delivery applications and suggest that they may be promising candidates for hydrogel-based agricultural delivery systems. Full article

The rapid growth of electric mobility, renewable-energy storage, and portable electronics has sharply increased global lithium demand. Conventional lithium extraction methods, including hard-rock mining and brine evaporation, are land-intensive, slow, water-consumptive, and carbon-intensive. Adsorption has therefore received substantial attention for lithium recovery, due to its simple operation, cost-effectiveness, and facile scalability. In this regard, zeolite-based adsorbents have emerged as promising next-generation materials, mainly because of their crystalline frameworks, tunable pore architectures, ion-exchange functionality, and exceptional thermal and chemical stability. Existing reviews on adsorption-based lithium recovery have predominantly focused on polymeric materials, ion-exchange resins, and lithium-ion sieves (including lithium manganese oxide-based, titanium-based, and aluminum hydroxide-based adsorbents). To fill this gap, we present a dedicated and comprehensive review of zeolite-based adsorbents for sustainable lithium recovery from non-conventional lithium resources such as brines, geothermal fluids, seawaters, and battery-recycling leachates. By systematically and rigorously analyzing existing studies on this topic, we identify five guiding design principles: (i) zeolite framework charge density, (ii) zeolite framework topology and pore architecture (iii) morphology (size and shape), (iv) zeolite-based hybrid materials, and (v) operational design parameters (e.g., pH and temperature). Each design element is discussed in depth to clarify how lithium adsorption capacity and selectivity, transport behavior, and adsorption mechanisms can be controlled across diverse feedstocks. We further discuss the advantages, limitations, and future research needs for zeolite-based lithium capture. To the best of our knowledge, this is the first review centered on zeolite-based materials for lithium recovery. The knowledge and insights provided here aim to drive researchers into advancing zeolite-based adsorbents toward sustainable, next-generation lithium recovery technologies. Full article

Mathematical modeling of degradation data is essential for quantifying the lifetime, reliability, and long-term stability of advanced materials when a direct experimental assessment is costly or limited. This paper develops an applied statistical framework based on the proportional hazard Gumbel Type-II (PHGT-II) distribution for modeling positive degradation times under a generalized progressive hybrid censoring scheme. The proposed model extends the baseline Gumbel Type-II distribution through a proportional hazard structure, providing additional flexibility for representing non-monotone hazard behavior, heavy-tailed lifetime patterns, and heterogeneous degradation mechanisms. The probability density, survival, hazard, and mean time to failure functions were derived, and the likelihood function was formulated under generalized progressive hybrid censoring. Parameter estimation was performed using maximum likelihood estimation and Bayesian inference with independent Gamma priors. Bayesian estimates were obtained under squared error and general entropy loss functions using a Metropolis–Hastings algorithm. The model was applied to thermal degradation data of the hydroxylated fullerene nanocomposite ${\mathrm{Sc}}_3\mathrm{N}@{\mathrm{C}}_{80}{\left(\mathrm{OH}\right)}_{18}$, where the degradation time was defined through a 2% weight-loss threshold obtained from a thermogravimetric analysis. The PHGT-II model was compared with other distributions using several goodness-of-fit measures. The results show that the PHGT-II distribution provides the best fit to the observed degradation data and yields consistent reliability estimates across maximum likelihood and Bayesian approaches. The proposed framework offers a flexible and interpretable tool for modeling censored degradation data and can be extended to other reliability and lifetime applications in engineering and material science. Full article

The growing demand for efficient, stable, and environmentally friendly materials for next-generation optoelectronic and photovoltaic applications has attracted significant interest in double perovskite compounds. First-principles density functional theory (DFT) calculations were performed to systematically investigate the structural, mechanical, electronic, and optical properties of Ba₂MReO₆ (M = Li, Na, K, and Rb) double perovskites. Structural optimization confirms that all compounds crystallize in the cubic Fm3̅m symmetry. The thermodynamic and geometric stability of the series is checked with negative formation energies and tolerance factor analyses (t, μ, τ). Mechanical analysis confirms that all compounds are mechanically stable; Ba₂LiReO₆ is the stiffest, while Ba₂RbReO₆ shows moderate stiffness with the highest ductility. Furthermore, ab initio molecular dynamics (AIMD) simulations at room temperature confirm the dynamical stability of all compounds, with negligible fluctuations in total energy under thermal conditions. The calculated band structures using both GGA-PBE and HSE06 hybrid functionals reveal that all compounds possess indirect band gaps, with HSE06 values of 2.236 eV for Ba₂LiReO₆, 2.133 eV for Ba₂NaReO₆, 2.116 eV for Ba₂KReO₆, and 1.395 eV for Ba₂RbReO₆. Optical measurements indicate that it is highly polarizable by dielectric polarizability, has high absorption coefficients (approximately 10⁶ cm⁻¹), and has large optical conductivity in the UV, with large inter-band interactions between 2 and 4 eV. The suitable band gap and favorable optical characteristics suggest that Ba₂RbReO₆ is the most promising candidate for photovoltaic and solar-cell applications. Full article

A novel Dy³⁺-doped self-activated Sr₂NaMg₂V₃O₁₂ (SNMVO) phosphor was synthesized via a high-temperature solid-state reaction method. Its microstructure, surface morphology, valence state, and luminescence properties were investigated. The results showed that the prepared phosphor exhibited bright green emission at 521 nm and yellow emission at 575 nm under 345 nm excitation. The luminescence intensity showed a strong concentration dependence, with an optimal Dy³⁺ ion doping concentration of 0.05 mol, and the concentration quenching (CQ) mechanism was dipole–dipole (d-d) interaction. Energy transfer between vanadate and Dy³⁺ was observed, with a maximum transfer efficiency of 63.5%. The thermal activation energy (0.1859 eV) indicated good thermal stability. Furthermore, this phosphor can be used as a yellow phosphor for white light-emitting diodes (wLEDs) and for anti-counterfeiting patterns. Full article

Physical treatment can improve the quality and overall characteristics of insoluble dietary fiber (IDF). This study investigated the effects of microjet homogenization treatment (MT), ultra-high-pressure treatment (HP), and ultrasonic treatment (UT) on the compositional profile, microstructure, basic properties, and bioactivity of IDF from okara. The modification processes increased IDF yield (unmodified IDF: 65.55%; MT-IDF: 70.51%; HP-IDF: 75.29%; UT-IDF: 79.09%). The mechanical action disrupted the compact structure, refined the particles, and increased the specific surface area (SSA). Compared with unmodified IDF (0.18 m²/g), the SSA values of MT-IDF, HP-IDF and UT-IDF increased by 83.33%, 50.00%, and 72.22%, respectively, thereby improving the overall hydration characteristics and adsorption performance of IDF. UT-IDF exhibited excellent water-holding capacity (8.11 g/g), yet its thermal stability ((mass loss: unmodified IDF (36.50%), MT-IDF (23.59%), HP-IDF (26.11%), and UT-IDF (33.74%)) and rheological properties (shear rate range of 35–40 s⁻¹: unmodified IDF (1.77 Pa·s), MT-IDF (15.86 Pa·s), HP-IDF (21.11 Pa·s), UT-IDF (5.36 Pa·s)) were relatively inferior to those of MT-IDF and HP-IDF. Notably, MT-IDF exhibited superior modification effects, including a loose, porous microstructure, enhanced adsorption performance, and favorable prebiotic potential (Lactobacillus acidophilus 36h-OD₆₀₀: 0.594; Bifidobacterium longum 36h-OD₆₀₀: 0.509). Among the three physical modification methods, MT offers significant advantages in enhancing the quality of IDF from okara, improving its processing suitability, and facilitating its high-value utilization. However, this study still has certain limitations: the evaluation of the correlation between fiber digestion rate and probiotic potential was based only on in vitro models and has not been systematically evaluated using real food matrices. Full article

The growing demand for flexible and environmentally friendly energy storage systems has increased interest in new electrolyte materials capable of operating at low temperatures. In this work, hydrogel polymer electrolytes based on aqueous choline lactate solutions were developed and evaluated for supercapacitor applications. Choline lactate was synthesized from biodegradable and low-toxicity substrates and characterized using spectroscopic and thermal analysis methods. A series of aqueous electrolytes with different salt concentrations was prepared, and their viscosity, density, and ionic conductivity were investigated to determine the optimal composition for hydrogel preparation. The obtained hydrogels were synthesized by photopolymerization and showed good flexibility, transparency, and structural stability without electrolyte leakage. Thermal analysis revealed that the presence of choline lactate effectively suppressed water crystallization, reducing the phase transition temperature of the hydrogel systems below −44 °C. Ionic conductivity increased with electrolyte content and reached 22.3 mS·cm⁻¹ at room temperature for the hydrogel containing 90 wt% electrolyte. Mechanical measurements showed that increasing electrolyte concentration improved flexibility but reduced stiffness and compressive strength. Electrochemical tests demonstrated stable supercapacitor operation in the temperature range from 25 °C to −20 °C, although lower temperatures led to decreased capacitance and increased internal resistance. The results indicate that choline lactate-based hydrogels are promising candidates for sustainable low-temperature energy storage devices. Full article

This study investigates the tribological performance of gum arabic (GA)-reinforced epoxy (EP) overlays on EN8 steel. Four GA concentrations (0.25, 0.5, 1, and 3 wt.%) were incorporated into the epoxy matrix to prepare overlays designated as EPGA1–EPGA4. Tribological performance was evaluated using a reciprocating tribometer under varying loads (5–20 N), sliding frequencies (1–2.5 Hz), and temperatures (40–70 °C). An L16 orthogonal array based on the Taguchi method was used to design the experimental matrix, and multi-criteria decision-making using the TOPSIS technique was employed to identify the optimum tribological condition based on minimum coefficient of friction (COF) and specific wear rate (SPWR). The optimum condition was obtained for the EPGA3 overlay (1 wt.% GA) at 5 N, 2 Hz, and 60 °C, which exhibited the lowest COF of 0.0567 ± 0.0021 and negligible wear. In contrast, the pure epoxy overlay showed severe adhesive wear, catastrophic delamination, a high COF of 1.15 ± 0.0023, and a wear rate of 163 × 10⁻⁸ mm³/Nm. Thermal characterization showed that GA improved the thermal stability and thermal transition behaviour of the epoxy matrix. Thermogravimetric analysis revealed an increase in onset degradation temperature from 320 °C for pure EP to 342 °C for EPGA4, while differential scanning calorimetry showed that EPGA3 exhibited the highest glass transition temperature (~118 °C), indicating improved interfacial interactions and restricted polymer-chain mobility. Nanoindentation and pull-off adhesion tests further confirmed the improved mechanical integrity and interfacial adhesion of the GA-reinforced overlays, demonstrating its potential as a sustainable reinforcement for tribological coating applications. Full article

Organic cathode materials (OCMs) are widely regarded as promising candidates for sustainable rechargeable batteries; however, their practical application is hindered by insufficient electrochemical performance and a lack of scalable synthesis methods. Building on our previous study of poly(o-phenylenediamine) (PoPDA), we herein present a single-precursor, solid-phase synthesis of poly(o-phenylenediamine) sulfide derivatives (PoPDAS). Using o-phenylenediamine sulfide (oPDAS) as the sole precursor, thermal treatment at 300–350 °C triggers H₂SO₄ and its decomposition products to simultaneously drive oxidative polymerization forming a conjugated PoPDA backbone, and in situ sulfurization introducing polysulfide (–S_n–) linkages. The dual redox activity of C=N bonds in phenazine repeating units and S–S bonds in –S_n– linkages enables a high theoretical capacity, while the robust polymer matrix effectively confines soluble sulfur species during cycling. To optimize the trade-off between reversible capacity and long-term stability, a secondary sulfurization step has been implemented. Among fourteen samples prepared via varied synthetic routes and conditions, PoPDAS-B-350-0.5 with a moderate sulfur content of 27 wt% exhibits the best performance, delivering a reversible capacity of 358 mAh g⁻¹ and 88% capacity retention after 800 cycles. Electrochemical analysis and ex situ characterization confirm the redox mechanism involving both C=N and S–S groups, and reveal the excellent cycling stability attributed to the robust polymer backbone that confines dissociated sulfur species. These results highlight the potential of integrating multiple redox-active moieties into a polymer architecture via a scalable solid-phase synthesis to afford practical OCMs. Full article

The increasing penetration of renewable energy in active distribution networks introduces severe power fluctuations and uncertainties. This challenges traditional scheduling methods that rely on conservative and static capacity boundaries of converter-interfaced equipment. This paper proposes a multi-time-scale secure and economic dispatch framework that explicitly integrates the dynamic operating characteristic constraints of grid-forming converters. First, a spatial correlation model based on Copula theory is established to handle wind power uncertainties via scenario generation and reduction for the day-ahead and intra-day scheduling phases. This formulation aims to minimize the comprehensive operational costs of the system. For the real-time rolling optimization phase, the short-term overload potential of grid-forming converters, which is unlocked by electro-thermal coupling optimization and discontinuous pulse width modulation phase-shift clamping, is mathematically abstracted into a generalized dynamic elliptical active and reactive power capability envelope. This cross-scale mapping mechanism allows the system to utilize transient thermal margins for enhanced local reactive power support without violating device junction temperature limits. Furthermore, the non-convex scheduling model is transformed into a mixed-integer second-order cone programming problem using convex relaxation techniques to guarantee global optimality and computational efficiency. Comprehensive case studies on the modified IEEE 33-bus and 69-bus systems demonstrate that the proposed strategy reduces tie-line power fluctuations and operational costs under extreme conditions. The results achieve a favorable economic trade-off between brief power quality degradation and global physical stability. Full article