Search Results (1,668)

The synthesis, characterization, and equilibrium studies of complexes of selected lanthanide ions Eu(III), Gd(III), and Tb(III) with the ligand 1,3-bis(3-bromo-5-chlorosalicylideneamino)-2-propanol (H₃L) are reported. It was found that in the solid state, the complexes with the formulas [Eu(H₃L)₂(NO₃)₃], [Gd(H₃L)₂(NO₃)₃], and [Tb(H₃L)₂(NO₃)₃] are formed. In solution, complexes with stoichiometries of Ln(III):H₃L 1:1 and 1:2 were obtained. The ligand H₃L was isolated in crystalline form, and its molecular structure and conformation were determined by single-crystal X-ray diffraction analysis. The compounds were further characterized by elemental analysis, infrared spectroscopy, ¹H NMR, ¹³C NMR techniques, and mass spectrometry (ESI), confirming the formation of the Schiff base group. Stability constants of the complexes in solution were determined using potentiometric titration, providing insights into the metal-ligand binding equilibria. In addition, the spectroscopic properties of the ligand and its lanthanide(III) ion complexes were investigated by UV-Vis spectroscopy, which confirmed ligand-to-metal charge transfer interactions, as well as by luminescence measurements. The luminescence studies revealed inefficient energy transfer in [Eu(H₃L)₂(NO₃)₃] complexes, while no transfer was observed in [Tb(H₃L)₂(NO₃)₃] systems at any pH value. This behavior is attributed to the large energy gap between the ligand triplet state and the lowest resonant levels of the studied lanthanide ions. Full article

Lithium-ion batteries, widely used in phones and electric vehicles, pose safety concerns due to the flammability of conventional liquid electrolytes, which are prone to ignition under elevated temperatures and mechanical stress, increasing the risk of fire. Polymer electrolytes have been employed as a safer solution thanks to their superior thermal stability and mechanical strength. However, despite these advantages, many polymer matrices pose a fire hazard, limiting their potential. This review assesses recent advances in enhancing the flame retardancy of polymer electrolytes through a variety of strategies, namely the incorporation of flame-retardant additives, the addition of nanoscale fillers to improve thermal resistance, and the design of layered or hybrid polymer membrane structures that function as thermal barriers. This review evaluates the effectiveness of these methods, examining their flame-retardancy as well as their influences on ionic conductivity and overall battery performance. By highlighting recent progress and enduring safety challenges in solid-state batteries, it aims to offer insights for developing lithium batteries with enhanced safety and high performance. Full article

Respiratory syncytial virus (RSV) is a leading cause of respiratory infections in young children, elderly people, and patients with underlying diseases. Solid data on its epidemiology and burden of disease are essential for the implementation of preventive strategies. This review provides for the first time a comprehensive overview on publicly available RSV surveillance resources in Germany. Methods: Public RSV surveillance systems in Germany were identified and, where possible, exemplary data was extracted to provide an overview of the scope of available data, their strengths and limitations. Results: German RSV surveillance systems provide data on both outpatient and inpatient incidence rates, age distribution, and seasonality. Germany’s public health institution, the Robert Koch Institute (RKI), documents RSV cases nationwide based on mandatory reporting. Further, sentinel surveillance by RKI captures outpatient RSV infections as well as severe hospitalized cases. Nationwide, data on inpatients is collected and reported by hospital discharge diagnostic codes. Additional surveillance systems (e.g., clinical-virology.net) provide data on RSV positivity rates stratified by age and gender. Regional surveillance efforts by ten German states provide data on the infection dynamics. Pediatric documentation of age distribution and severity of respiratory diseases via surveillance was initiated by the German Society for Pediatric Infectious Diseases. Reviewing all available sources and data underlines the high clinical burden, especially in infants and older adults during the winter season. Conclusions: Germany’s RSV surveillance systems on the national and regional level support the tracking of incidence rates and seasonal patterns. Notably, pediatric data collection is more thorough, yielding a more comprehensive dataset than that available for adults. Contextualizing reported incidence rates in light of prospective or modeling studies suggests that the official documentation of RSV cases—particularly among adults—is underestimated. Full article

This study investigates CaCu_3−xSr_xTi₄O₁₂ (CCSTO) systems synthesized using the solid-state method, with x compositions of 0.00, 0.15, and 3.00. The samples were modified using 6 wt% graphene oxide (GO) and reduced GO (rGO) prepared via Hummer’s method to evaluate their performance as electrodes in supercapacitors. The results indicate that the addition of 6wt% rGO to CCTO (CCTO-6rGO) led to an improvement in specific capacitance, reaching 237.76 mF·g⁻¹ at a scan rate of 10 mV/s, compared to 29.86 mF·g⁻¹ for pure CCTO and only 7.83 mF·g⁻¹ for CCTO-6GO, suggesting that rGO enhances charge storage. For the CCTO15Sr samples, CCTO15Sr-6rGO exhibited the highest specific capacitance, with 321.63 mF·g⁻¹ at 10 mV/s, surpassing both pure CCTO15Sr (80.19 mF·g⁻¹) and CCTO15Sr-6GO (25.73 mF·g⁻¹). These results stem from oxygen and metal vacancies, which aid charge accumulation and ion diffusion. In contrast, adding GO generally reduced specific capacitance in all samples. The findings highlight CCSTO’s potential—especially with rGO modification—as a supercapacitor electrode while also indicating areas for further optimization. Full article

Corundum–mullite duplex ceramics were fabricated via a solid-state reaction technique using high-alumina fly ash and α-alumina powders. The effects of magnesium oxide on bulk density, apparent porosity, compressive strength, and microstructure of the duplex ceramics were investigated by scanning electronic microscopy, mechanical testing, and X-ray diffraction, respectively. Results showed that the prepared ceramics were mainly dominated by mullite and corundum phases, and the mullite was in the form of columns and crosses to form a net-like structure. The bulk density and the compressive strength increased with the increase in MgO addition, while the porosity decreased contrariwise. Optimal performance among tested compositions was observed at 12 wt% MgO addition, yielding a bulk density of 3.012 g·cm⁻³, a porosity of 8.12%, and a compressive strength of 263 MPa, demonstrating the potential of this composite for high-performance ceramic applications. Full article

Biomass briquettes are increasingly used as renewable solid fuels, yet their durability under humid storage remains a key limitation. This study evaluated the mechanical performance and water resistance of briquettes made from fine (0–1 mm) and coarse (0–3 mm) charcoal fractions using molasses as a primary binder, polyvinyl alcohol (PVA, 3–7%) as a synthetic binder, and liquid soap (1–9%) as a surfactant additive. Compressive strength was measured in the dry state, after four days of water immersion, and after re-drying, while water absorption was monitored over immersion times from 15 min to 4 days. Fine-fraction briquettes showed higher strength and lower water uptake than coarse fractions, with optimal PVA contents of 6–7% providing maximum dry and post-drying strength. Moderate soap addition (2–3%) improved binder dispersion and early wet strength, whereas higher levels (>5%) reduced durability. Water absorption kinetics indicated that particle size controlled early swelling, while binder composition influenced the rate but not the final saturation. The best performance in humid storage was achieved by 0–1 mm + 4% PVA and 0–1 mm + 5% PVA + 3% soap formulations. These results support the formulation of eco-friendly binder systems that balance strength, moisture resistance, and cost for large-scale biomass briquette production. Full article

Domoic acid (DA), produced by Pseudo-nitzschia diatoms, is the one of the major toxin threats from harmful algal blooms (HABs) on the west coast of the United States. DA events vary in magnitude, timing, and duration, and elucidating drivers for individual events is a persistent challenge. Monterey Bay experiences near-annual DA events and hosts long-term HAB monitoring at the Santa Cruz Municipal Wharf (SCW). Here we characterize two toxin events, occurring in May 2023 and March 2024. The events were similar in magnitude and duration, but an exploration of physical, biological, and chemical dynamics revealed distinct environmental drivers. These differences resulted in a significant deviation in cellular DA (cDA) within the same species of Pseudo-nitzschia. In addition, opportunistic solid-phase adsorption toxin tracking (SPATT) was used for environmental metabolomics. The novel application of SPATT revealed 159 metabolites that were strongly correlated with DA in both events and produced a spectral match to a new marine natural product using Global Natural Products Social Molecular Networking (GNPS). This work takes a multivariable approach to understanding toxin drivers and lends proof of concept for the integration of environmental metabolomics in HAB monitoring. Full article

Vanillin is the compound widely used in the food industry as a flavoring agent. Currently, chemically synthesized vanillin provides the majority of the world’s supply. Due to the increase in consumer awareness, there is a change in preferences towards natural food additives. The main goal of this research was to obtain vanillin through Solid-State Fermentation on agri-food by-products such as brewer’s spent grain, wheat bran, and linseed oil cake. A specially designed SSF culture single-use bag bioreactor made of a poliamide-6 foil sleeve was used to conduct the process on a bench-scale (600 g of dry medium). After extraction and purification, obtained vanillin samples were subjected to sensory analysis to determine whether the origin of microbiologically obtained vanillin affects its aromatic properties. The panelists assessed that the extracts obtained from the cultures of P. chrysosporium CBS246.84 and F. culmorum MUT5855 proved to be attractive flavors as they showed more attractive sensory properties than synthetic vanillin and were comparable to commercially available vanilla bean extract. This is the first study to include sensory analysis of vanillin obtained biotechnologically by the SSF method. Full article

Friction stir additive manufacturing (FSAM) is a promising solid-state technique for fabricating high-strength aluminum alloys, such as Al-7075, which are difficult to process using conventional melting-based additive manufacturing (AM) methods. This study investigates the mechanical properties and tool wear behavior of seven-layered Al-7075 multi-layered composites reinforced with silicon carbide (SiC) and titanium carbide (TiC) fabricated via FSAM. Microstructural analysis confirmed defect-free multi-layered composites with a homogeneous distribution of SiC and TiC reinforcements in the nugget zone (NZ), although particle agglomeration was observed at the bottom of the pin-driven zone (PDZ). The TiC-reinforced composite exhibited finer grains than the SiC-reinforced composite in both as-welded and post-weld heat-treated (PWHT) conditions, achieving a minimum grain size of 1.25 µm, corresponding to a 95% reduction compared to the base metal. The TiC-reinforced multi-layered composite demonstrated superior mechanical properties, attaining a microhardness of 93.7 HV and a UTS of 263.02 MPa in the as-welded condition, compared to 88.6 HV and 236.34 MPa for the SiC-reinforced composite. After PWHT, the TiC-reinforced composite further improved to 159.12 HV and 313.46 MPa UTS, along with a higher elongation of 11.14% compared to 7.5% for the SiC-reinforced composite. Tool wear analysis revealed that SiC reinforcement led to greater tool degradation, resulting in a 1.17% weight loss. These findings highlight the advantages of TiC reinforcement in FSAM, offering enhanced mechanical performance with reduced tool wear in multi-layered Al-7075 composites. Full article

The increasing penetration of wind energy into modern power grids introduces new challenges, particularly regarding fault current levels and voltage stability during disturbances. This study proposes and evaluates a new Solid State Fault Current Limiter (SSFCL) topology for mitigating the adverse effects of faults in wind-integrated power systems. The proposed SSFCL consists of a bridge section and a shunt branch, designed to limit fault current while maintaining power quality. Unlike conventional SSFCLs, the proposed topology incorporates both DC and AC reactors with an Integrated Gate-Commutated Thyristor (IGCT) switch, to provide current limiting and voltage stabilization, effectively mitigating the negative impacts of faults. A comprehensive MATLAB/Simulink-based simulation is conducted on a realistic grid model. First, appropriate AC and DC reactor impedances are selected to balance fault current suppression, cost, and dynamic response. Then, three fault scenarios, transmission line, distribution grid, and domestic network, are analyzed to assess the fault current limiting performance and voltage sag mitigation of the SSFCL. In the simulation analysis, the DC reactor current and the voltage across the SSFCL device are continuously monitored to evaluate its dynamic response and effectiveness during fault and normal operating conditions. In addition, the fault current contribution from the wind farm is assessed with and without the integration of the SSFCL, along with the voltage profile at the Point of Common Coupling (PCC), to determine the limiter’s impact on system stability and power quality. Finally, the performance of the proposed SSFCL is compared to that of the resistive-type superconducting fault current limiter (R-SFCL) under identical fault scenarios to assess the technical and economic standpoints of the proposed SSFCL. Simulation results show that the SSFCL reduces the peak fault current by up to 29% and improves the voltage profile at the PCC by up to 42%, providing comparable performance to the R-SFCL while avoiding the need for cryogenic systems. Full article

Due to its unique benefits over conventional subtractive manufacturing, additive manufacturing methods continue to attract interest in both academia and industry. One such method is called Cold Spray Additive Manufacturing (CSAM), a solid-state coating deposition technology to manufacture repair metallic components using a gas jet and powder particles. CSAM offers low heat input, stable phases, suitability for heat-sensitive substrates, and high deposition rates. However, persistent challenges include porosity control, geometric accuracy near edges and concavities, anisotropy, and cost sensitivities linked to gas selection and nozzle wear. Interdisciplinary research across manufacturing science, materials characterisation, robotics, control, artificial intelligence (AI), and machine learning (ML) is deployed to overcome these issues. ML supports quality prediction, inverse parameter design, in situ monitoring, and surrogate models that couple process physics with data. To demonstrate the impact of AI and ML on CSAM, this study presents a systematic literature review to identify, evaluate, and analyse published studies in this domain. The most relevant studies in the literature are analysed using keyword co-occurrence and clustering. Four themes were identified: design for CSAM, material analytics, real-time monitoring and defect analytics, and deposition and AI-enabled optimisation. Based on this synthesis, core challenges are identified as small and varied datasets, transfer and identifiability limits, and fragmented sensing. Main opportunities are outlined as physics-based surrogates, active learning, uncertainty-aware inversion, and cloud-edge control for reliable and adaptable ML use in CSAM. By systematically mapping the current landscape, this work provides a critical roadmap for researchers to target the most significant challenges and opportunities in applying AI/ML to industrialise CSAM. Full article

In this study, Ni₃₇Co₁₃Mn_33.5+xTi_16.5–x alloys with different particle sizes (75–150 μm, 50–75 μm, 0–50 μm) were successfully fabricated using spark plasma sintering under different processing conditions. By adjusting the composition of alloy and particle size, a significant transformation entropy change and the generation of a suitable amount of second phases along the grain boundaries were achieved in the SPS Ni₃₇Co₁₃Mn_34.5Ti_15.5 alloy with a particle size range of 0–50 μm. The mechanical properties of this optimized alloy were excellent, exhibiting a compressive strength of 2005 MPa and a fracture strain of 27%. Furthermore, under a loading rate of 0.28 s⁻¹, the alloy demonstrated an adiabatic temperature change of up to 34.2 K. In addition, the alloy also exhibited a barocaloric effect under low-pressure conditions, achieving a substantial entropy change of 16.1 J·kg⁻¹·K⁻¹ and an estimated adiabatic temperature change of 11.2 K under 100 MPa pressure. Through these results, SPS Ni₃₇Co₁₃Mn_34.5Ti_15.5 alloy is proved to be a potential candidate for solid-state refrigeration applications. Full article

Liquid microlenses and their arrays (LMLAs) have emerged as a transformative platform in adaptive optics, offering superior reconfigurability, compactness, and fast response compared to conventional solid-state lenses. This review summarizes recent progress from an application-oriented perspective, focusing on actuation mechanisms, fabrication strategies, and functional performance. Among actuation mechanisms, electric-field-driven approaches are highlighted, including electrowetting for shape tuning and liquid crystal-based refractive-index tuning techniques. The former excels in tuning range and response speed, whereas the latter enables programmable wavefront control with lower optical aberrations but limited efficiency. Notably, double-emulsion configurations, with fast interfacial actuation and inherent structural stability, demonstrate great potential for highly integrated optical components. Fabrication methodologies—including semiconductor-derived processes, additive manufacturing, and dynamic molding—are evaluated, revealing trade-offs among scalability, structural complexity, and cost. Functionally, advances in focal length tuning, field-of-view expansion, depth-of-field extension, and aberration correction have been achieved, though strong coupling among these parameters still constrains system-level performance. Looking forward, innovations in functional materials, hybrid fabrication, and computational imaging are expected to mitigate these constraints. These developments will accelerate applications in microscopy, endoscopy, AR/VR displays, industrial inspection, and machine vision, while paving the way for intelligent photonic systems that integrate adaptive optics with machine learning for real-time control. Full article

Large-scale integration of distributed energy resources (DERs) into distribution networks causes topological-operational situations with multidirectional power flows. One of the main components of distribution networks is the power transformer, which does not have the capabilities for real-time control of distribution network parameters with DERs. The use of solid-state transformers (SSTs) for connecting medium-voltage (MV) and low-voltage (LV) distribution networks of both alternating and direct current has great potential for constructing new distribution networks and enhancing the existing ones. Electricity losses in distribution networks can be reduced through the establishment of MV and LV DC networks. In hybrid AC-DC distribution networks, the SSTs can be especially effective, ensuring compensation for voltage dips, fluctuations, and interruptions; regulation of voltage, current, frequency, and power factor in LV networks; and reduction in the levels of harmonic current and voltage due to the presence of power electronic converters (PECs) and capacitors in the DC link. To control the operating parameters of hybrid distribution networks with solid-state transformers, it is crucial to develop and implement advanced control systems (CSs). The purpose of this review is a comprehensive analysis of the features of the creation of CSs SSTs when they are used in hybrid distribution networks with DERs to identify the most effective principles and methods for managing SSTs of different designs, which will accelerate the development and implementation of CSs. This review focuses on the design principles and control strategies for SSTs, guided by their architecture and intended functionality. The architecture of the solid-state transformer control system is presented with a detailed description of the main stages of control. In addition, the features of the SST CS operating under various topologies and operating conditions of distribution networks are examined. Full article

The continuous advancement of the food industry is accompanied by increased generation of animal waste, including poultry feathers. Composting presents a sustainable alternative to disposal methods such as incineration by converting waste into valuable fertilizer products. This study aimed to evaluate the impact of inoculation with the keratinolytic strain Bacillus subtilis P22 on the quality and maturity of compost produced from feathers combined with organic additives (wood shavings and lignite). The experiment involved evaluation of the keratinolytic potential of the tested strain, and characterization of its proteolytic enzymes, solid-state cultures and composting conducted at semi-technical scale. The B. subtilis P22 strain demonstrated the ability to solubilize 78% of feather material within 7 days of cultivation. The keratinolytic enzyme complex was likely dominated by polycatalytic alkaline serine proteases, i.e., subtilisins. The effectiveness of the inoculum was confirmed in laboratory solid-state cultures, where the dry mass loss in inoculated samples was twice that of the control containing only endogenous microflora. At the semi-technical scale, inoculation with B. subtilis P22 significantly accelerated compost maturation and mineralization (C/N = 10.2; N-NH₄⁺/N-NO₃⁻ = 0.4; Cw/Corg = 0.9) compared to the control. The final compost’s mineral composition indicates its potential for use as an organic soil amendment. Full article