Search Results (940)

With the rapid advancement of energy storage technologies, there is a growing demand for affordable, efficient, and environmentally benign battery systems. Sodium-ion batteries (SIBs) present a promising alternative to lithium-ion systems due to sodium’s high abundance and similar electrochemical properties. Particular attention is given to developing NASICON -sodium (Na) super ionic conductor, type cathode materials, especially Na3V2(PO4)3, which exhibits high thermal and structural stability. This study focuses on the sol–gel synthesis of Na₃V₂(PO₄)₃ using citric acid and ethylene glycol, as well as investigating the effect of annealing temperature (400–1000 °C) on its structural and electrochemical properties. Phase composition, morphology, textural characteristics, and electrochemical performance were systematically analyzed. Above 700 °C, a highly crystalline NASICON phase free of secondary impurities was formed, as confirmed by X-ray diffraction (XRD). Microstructural evolution revealed a transition from a loose amorphous structure to a dense granular morphology, accompanied by changes in specific surface area and porosity. The highest surface area (67.40 m²/g) was achieved at 700 °C, while increasing the temperature to 1000 °C caused pore collapse due to sintering. X-ray photoelectron spectroscopy (XPS) confirmed the predominant presence of V³⁺ ions and the formation of V⁴⁺ at the highest temperature. The optimal balance of high crystallinity, uniform elemental distribution, and stable texture was achieved at 900 °C. Electrochemical testing in a Na/NVP half-cell configuration delivered an initial capacity of 70 mAh/g, which decayed to 55 mAh/g by the 100th cycle, attributed to solid-electrolyte interphase (SEI) formation and irreversible Na⁺ trapping. These results demonstrate that the proposed approach yields high-quality Na₃V₂(PO₄)₃ cathode materials with promising potential for sodium-ion battery applications. Full article

The seafood industry is increasingly adopting intelligent packaging to preserve product quality and improve freshness transparency. This study developed and evaluated a pH-sensitive freshness indicator (FI) for skate sashimi (Zearaja chilensis). This product is consumed at varying stages of fermentation. The FI incorporated bromothymol blue (BTB) and bromocresol purple (BCP) in a polymer matrix. It targeted volatile basic nitrogen (VBN) compounds, with trimethylamine (TMA) as the primary marker. As freshness declined, VBN compounds accumulated in the package headspace and caused a gradual FI color change from yellow to blue through pH variation. ΔE increased from 7.72 on day 2 to 23.52 on day 3. This marked the onset of visible color change and the FI reached full blue by day 7. Headspace solid-phase microextraction (HS-SPME) and gas chromatography–flame ionization detection (GC-FID) quantified monomethylamine (MMA), dimethylamine (DMA) and TMA throughout storage. ΔE correlated strongly with total bacterial count (TBC, r = 0.978), pH (r = 0.901) and TMA (r = 0.888). These results indicate that microbial growth, alkalinity increase and amine production were closely associated with color transitions. The FI reliably tracked freshness loss in skate sashimi. It has potential to enhance consumer transparency and strengthen quality control in the seafood supply chain. Full article

This study evaluates the impact of mineralogy, elemental composition, and reaction pathways on hydrogen (H₂) generation in seven ultramafic and mafic (basaltic) rocks. Experiments were conducted under typical low-temperature hydrothermal conditions (150 °C) and captured early and evolving stages of fluid–rock interaction. Pre- and post-interactions, the solid phase was analyzed using X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS), while Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine the composition of the aqueous fluids. Results show that not all geologic H₂-generating reactions involving ultramafic and mafic rocks result in the formation of serpentine, brucite, or magnetite. Our observations suggest that while mineral transformation is significant and may be the predominant mechanism, there is also the contribution of surface-mediated electron transfer and redox cycling processes. The outcome suggests continuous H₂ production beyond mineral phase changes, indicating active reaction pathways. Particularly, in addition to transition metal sites, some ultramafic rock minerals may promote redox reactions, thereby facilitating ongoing H₂ production beyond their direct hydration. Fluid–rock interactions also regenerate reactive surfaces, such as clinochlore, zeolite, and augite, enabling sustained H₂ production, even without serpentine formation. Variation in reaction rates depends on mineralogy and reaction kinetics rather than being solely controlled by Fe oxidation states. These findings suggest that ultramafic and mafic rocks may serve as dynamic, self-sustaining systems for generating H₂. The potential involvement of transition metal sites (e.g., Ni, Mo, Mn, Cr, Cu) within the rock matrix may accelerate H₂ production, requiring further investigation. This perspective shifts the focus from serpentine formation as the primary driver of H₂ production to a more complex mechanism where mineral surfaces play a significant role. Understanding these processes will be valuable for refining experimental approaches, improving kinetic models of H₂ generation, and informing the site selection and design of engineered H₂ generation systems in ultramafic and mafic formations. Full article

The chemical and structural similarity of calcium orthophosphates to hard tissues in the human body makes them suitable as biomaterials for bone implants, cements, injection systems, etc., for bone regeneration and reconstruction. Tetracalcium phosphate (Ca₄(PO₄)₂O, TTCP) is a promising component for such biomaterials due to its high calcium content and alkaline nature. The former makes it suitable for promoting mineralization, while the latter supports neutralization of the acidic environment, helping to prevent inflammation and improve the biocompatibility of the materials. However, it is the least used calcium orthophosphate due to the difficulties in its synthesis. This study examines the effect of high-energy mechanochemical activation on the phase evolution, particle morphology, and thermal behaviour of equimolar mixtures of Ca(OH)₂ and CaHPO₄, with the aim of optimizing precursor conditions for the synthesis of (TTCP)-rich ceramic materials. The results demonstrate that mechanochemical activation effectively induces structural disorder, promotes the formation of amorphous and nanocrystalline phases, and facilitates subsequent phase transitions upon calcination. The combined use of solid-state NMR, XRD, TEM, and thermal analysis provides a comprehensive understanding of the transformation pathways. Ultimately, 24 h of activation under the experimental conditions was identified as optimal for producing a precursor with a favorable phase composition for obtaining TTCP-rich ceramic materials after calcination at 1350 °C. Full article

Conversion-type transition metal oxides (TMOs) have emerged as promising anode materials for lithium-ion batteries (LIBs) owing to their high theoretical capacities and low cost. Intriguingly, many TMOs exhibit extra capacity that surpasses the limits predicted by conversion reaction mechanisms, challenging traditional electrochemical models and offering opportunities for next-generation high-energy storage. This review highlights the phenomenon of extra capacity in TMO anodes, emphasizing its mechanistic origins and practical implications. While these materials face well-known challenges such as low initial coulombic efficiency, solid electrolyte interphase (SEI) instability, and severe structural degradation due to large volume changes, they offer promising opportunities for achieving high energy density. Special emphasis is placed on understanding the underlying mechanisms that contribute to this anomalous capacity, including the role of reversible SEI formation, lithium-rich phases, reversible formation of LiOH, and interfacial storage phenomena. By clarifying these mechanisms and performance-enhancement approaches, this paper aims to guide future research toward the practical application of high-capacity conversion-type TMO anodes in next-generation LIBs. Full article

Decarbonizing the steel industry relies on a transition from carbon-intensive blast furnace technology to scrap-based secondary steelmaking using electric arc furnaces. This transition introduces tramp elements and leads to their gradual accumulation, which can significantly influence the functional properties of chemically sensitive steel grades. In this study, the combined impact of several tramp element contents on the phase transformations, microstructure and mechanical properties of a 0.3 wt.% C low-alloyed steel was investigated. To achieve this, a reference alloy was produced using the conventional blast furnace production route. It was then compared with two trial alloys, which contained intentionally elevated levels of tramp elements and were produced through an experimental melting route designed to simulate scrap-based electric arc furnace production. The experimental characterization included light optical and electron microscopy, electron back-scatter diffraction, in situ synchrotron high-energy X-ray diffraction coupled with dilatometry, and Vickers hardness testing. The results revealed the formation of displacive transformation products such as martensite and showed that austenite was retained in the tramp element-enriched trial alloys. The combination of solid solution strengthening and martensitic transformation led to a gradual increase in hardness. These findings underscore the critical role of tramp elements in determining the microstructural and mechanical response of steels produced from scrap-based feedstock. Full article

This study prepared an adsorption-based water-containing lunar regolith simulant under low-temperature conditions to investigate H₂O behavior in simulated lunar environments. Experiments established that water binds to regolith particles via adsorption rather than existing in liquid/solid states, with critical initial pressure thresholds identified at various temperatures to ensure pure adsorption conditions. Crucially, coexisting substances extend H₂O preservation to −100 °C, suggesting substantial water retention in lunar polar regolith even under extreme cold. Sublimation modeling further revealed phase transition boundaries, indicating water ice likely persists in both permanently shadowed regions and illuminated polar areas. These findings provide fundamental insights into: adsorption-driven enrichment/preservation mechanisms of lunar water, thermodynamic stability thresholds at ultralow temperatures, and water ice distribution patterns across lunar polar terrains. The data advance understanding of lunar water’s stability and extractability, offering critical scientific support for future in situ resource utilization and sustained lunar exploration. Full article

Background/Objectives: Conventional solid dispersion methods face significant industrial limitations, including thermal degradation, residual organic solvents, and complex preparation processes. This study presents a novel decrystallizing formulation using poloxamer and propylene glycol that remains solid during storage but liquefies at physiological temperature (37 °C). Methods: Decrystallizing formulations containing various poloxamer types (407 and 188) at different concentrations (5–25% w/w) were prepared and assessed for decrystallization temperature, decrystallization time, and drug solubility. The optimal formulation was further characterized using FTIR analysis, as well as in vitro liquefaction performance and dissolution studies. Finally, the industrial sustainability of the decrystallizing formulation was assessed against conventional methods. Results: Poloxamer 407 exhibited higher decrystallization temperature, longer decrystallization time, and superior solubilization capacity compared to Poloxamer 188. Maximum drug solubility (5.51 ± 0.08 mg/g) was achieved at 20% w/w of poloxamer 407 with a decrystallization temperature of 37 °C, and it took 216 s for decrystallization. FTIR spectroscopy confirmed hydrogen bonding interactions, which are responsible for temperature-dependent phase transitions. The decrystallizing formulation showed remarkable improvement in dissolution efficiency (80.6 ± 3.9%) compared to the raw drug (1.8 ± 0.8%), a physical mixture (11.1 ± 6.0%), and a marketed tablet (30.8 ± 2.2%). Conclusions: The current decrystallizing formulation offers a promising approach for improving the bioavailability of poorly water-soluble drugs and tackling the limitations of conventional methods. Moreover, it provides additional advantages in terms of industrial sustainability for continuous production compared to conventional approaches. Full article

Isosymmetric phase transitions (IPTs) represent a rare class of solid-state transformations in which substantial structural reorganization occurs without a change in crystallographic symmetry. These phenomena, though subtle, can have a profound impact on the physical and functional properties of materials, offering novel opportunities for property tuning without chemical modification. This review provides a comprehensive overview of the experimental and computational methods used to detect and characterize IPTs, including single-crystal and powder X-ray diffraction, Raman and FT-IR spectroscopy, differential scanning calorimetry, and advanced simulation techniques such as density functional theory, molecular dynamics, and crystal structure prediction. Special emphasis is placed on correlating local structural rearrangements—such as hydrogen-bond reconfiguration, polyhedral tilting, and molecular fragment reorientation—with macroscopic thermodynamic signatures. A broad selection of examples from the literature is discussed, covering molecular crystals, coordination compounds, organic functional materials, simple salts, and inorganic oxides, with detailed tables summarizing pressure- and temperature-induced IPTs. The review also analyses the primary factors that trigger IPTs, particularly temperature and pressure, and examines their role in governing structural stability and transformation pathways. By combining structural, spectroscopic, and thermodynamic perspectives, this work aims to consolidate the understanding of IPT mechanisms and to highlight their significance for the design of responsive crystalline materials. Full article

BaTiO₃ (BT)-based lead-free ceramics are regarded as highly promising candidates for solid-state electrocaloric (EC) cooling devices due to their large spontaneous polarizations, shiftable Curie temperatures, and environmental friendliness. This review summarizes recent progresses in the design and optimization of BT-based EC ceramics. Key aspects include thermodynamic principles of the EC effect (ECE); structural phase transitions; and strategies such as constructing relaxor ferroelectrics, multi-phase coexistence, etc. Finally, future research directions are proposed, including the exploration of local microstructural evolution, polarization flip mechanisms, and bridging material design and device integration. This work aims to provide insights into the development of high-performance BT-based materials for solid-state cooling devices. Full article

This study aims to bridge the critical knowledge gap in understanding the dynamic microstructural evolution during high-solid-fraction semi-solid rheo-die casting process, including slurry preparation (0.1–0.3 K/s) and rheo-die casting (10–150 K/s). A novel phase-field model coupling continuous cooling with explicit nucleation was developed, enabling the dynamic simulation of continuous solidification microstructure evolution, considering two-stage cooling rate transition characteristics. Integrated the Swirled Enthalpy Equilibration Device (SEED) slurry preparation and graded-cooling mold experiments established variable cooling rate and solid fraction conditions for quantitative analysis of α-Al morphological evolution during rheo-die casting solidification. Through experimental and simulation investigations of the Al-7Si alloy, it is concluded that during Stage I slurry preparation, the primary α₁-Al phase coarsened due to Ostwald ripening. In Stage II rheo-die casting, primary α₁-Al undergoes continued growth under a moderate cooling rate (15 K/s). Meanwhile, secondary α₂-Al formation exhibits a cooling-rate and solid fraction dependence: a high cooling rate (150 K/s) promotes explosive nucleation with the volume fraction decreasing from 4.78% to 0.33% as the solid fraction rises, whereas a mid-cooling rate (15 K/s) substantially suppresses its formation. Mechanistically, a high cooling rate promotes solute trapping, which intensifies constitutional undercooling, thereby elevating both the nucleation and growth driving forces to facilitate the formation of secondary α₂-Al, whereas higher solid fractions restrict secondary phase formation by narrowing the solidification windows from 22 °C to 7 °C. Full article

Latent heat thermal energy storage (LHTES) based on phase change materials (PCMs) is receiving increasing interest since it offers high energy storage density while enabling the integration of variable renewable energies, hence boosting the transition towards a climate-neutral future. Despite the advantages that PCMs offer in providing a nearly isothermal solid–liquid phase transition, they still face some challenges that limit their deployment in real applications such as low thermal conductivity, phase separation, and supercooling, which affect charging and discharging rates. X-ray computed tomography (XCT) is a non-destructive imaging technique widely used in materials science for both qualitative and quantitative analysis of material microstructures and their evolution. Recent advances in laboratory-XCT instrumentation enabled short acquisition times on the order of tens of seconds which allows the investigation of dynamic processes in situ by time-lapse XCT measurements. These advances open new opportunities for revealing information on the morphology of solid–liquid PCMs. Despite the fact that XCT imaging has significant potential for energy research, its application in the field of PCMs is fairly new. A key enabler of applications of XCT to PCMs is the density difference between solid and liquid PCMs, which was found to be higher than 7% for all investigated PCMs. This enabled solid and liquid phases to be distinguished one from the other and properly quantified over time. The present work reviews the principles of laboratory-based XCT and the recent applications of XCT technology in the characterisation of PCMs, with emphasis on the study of the solid–liquid phase transition and validation of numerical PCM models by addressing the potentialities and challenges of XCT in PCM research. Full article

Background: Chimeric Antigen Receptor (CAR) T-cell therapy has transformed the treatment of hematological malignancies, yet its application in solid tumors remains constrained by unique biological and logistical barriers. Objective: This review critically examines the evolving landscape of CAR T-cell therapy in solid malignancies, with a focus on antigen heterogeneity, the immunosuppressive tumor microenvironment, and risks of on-target, off-tumor toxicity. Methods: We outline recent advances in CAR engineering, including co-stimulatory optimization, dual- and multi-antigen targeting, armored CARs, and gene-edited constructs designed to enhance persistence and anti-tumor activity. Clinical progress is highlighted by recent FDA approvals of genetically modified T-cell therapies in synovial sarcoma and melanoma, underscoring the potential for broader solid tumor application. Additionally, we synthesize early-phase clinical trial findings across multiple solid tumor types (e.g., lung, colorectal, ovarian, glioblastoma), and discuss innovative approaches such as regional delivery, checkpoint blockade combinations, and incorporation of chemokine receptors for improved tumor infiltration. The review also considers future strategies, including artificial intelligence-guided target discovery and rational trial design to overcome translational bottlenecks. Conclusions: With expanding clinical experience and continued technological innovation, CAR T-cell therapy is steadily transitioning from an experimental strategy to a therapeutic reality in solid tumors, poised to reshape the future of cancer immunotherapy. Full article

The reduced ductility caused by the brittle needle-like α′ martensite limits the application of TC4 alloys produced by selective laser melting (SLM). Appropriate heat treatment can improve the microstructures and properties of SLM-fabricated TC4 alloys. In this work, SLM-fabricated TC4 alloys underwent stress relief annealing at 600 °C and high-temperature annealing at 800 °C. The effects of heat treatment temperature on phase composition, microstructural morphology, grain orientation, and mechanical properties were investigated. Meanwhile, the microstructural evolution and fracture mechanisms during the heat treatment process were analyzed. The results indicate that after annealing at 600 °C, the needle-like α′ phase transforms into elongated α, and nano-β phase increases. When annealed at 800 °C, the α′ phase completely transforms into a more stable lath-shaped α phase and a short rod-shaped β phase, with the nano-β phase disappearing. The texture orientation gradually shifts from <0001> towards <01-10>, where slip systems are more active. Additionally, heat treatment promotes the transition of grain boundaries to high-angle grain boundaries, thereby alleviating stress concentration and enhancing solid-solution strengthening. After heat treatment, the ultimate tensile strength of the material slightly decreases, but the elongation significantly increases. As the annealing temperature increased, the elongation (EL) improved from 5.22% to 11.43%. Following high-temperature annealing at 800 °C, necking and larger dimples appear on the fracture surface, and the fracture mechanism shifts from a mixed brittle–ductile fracture to a ductile fracture. This work provides a theoretical basis for improving the microstructures and properties of SLM-fabricated TC4 alloys through heat treatment. Full article

This study focuses on the power systems of inland waterway vessels in Chinese Yangtze River, systematically outlining the low-carbon technology pathways for different power system types. A comparative analysis is conducted on the technical feasibility, emission reduction potential, and economic viability of LNG, methanol, ammonia, pure electric and hybrid power systems, revealing the bottlenecks hindering the large-scale application of each system. Key findings indicate that: (1) LNG and methanol fuels offer significant short-term emission reductions in internal combustion engine power systems, yet face constraints from methane slip and insufficient green methanol production capacity, respectively; (2) ammonia enables zero-carbon operations but requires breakthroughs in combustion stability and synergistic control of NO_X; (3) electric vessels show high decarbonization potential, but battery energy density limits their range, while PEMFC lifespan constraints and SOFC thermal management deficiencies impede commercialization; (4) hybrid/range-extended power systems, with superior energy efficiency and lower retrofitting costs, serve as transitional solutions for existing vessels, though challenged by inadequate energy management strategies and multi-equipment communication protocol interoperability. A phased transition pathway is proposed: LNG/methanol engines and hybrid systems dominate during 2025–2030; ammonia-powered systems and solid-state batteries scale during 2030–2035; post-2035 operations achieve zero-carbon shipping via green hydrogen/ammonia. Full article