Search Results (4,217)

The growing demand for sustainable, flexible, and high-performance electrode materials for energy storage has motivated the development of polymer-based composite electrodes with enhanced electrochemical properties. In this study, flexible cobalt oxide (Co₃O₄)-iron oxide (Fe₂O₃) nanoparticle-impregnated sodium alginate (NaAlg) as the polymer matrix composite membranes were developed via a simple solution-casting method to exploit the synergistic pseudocapacitive behaviour of mixed metal oxides together with the excellent film-forming ability, flexibility, and eco-friendly nature of NaAlg. The prepared membranes’ structural features, morphology, and electrochemical properties were examined through a set of techniques, such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Universal Testing Machine (UTM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation (PDP), and galvanostatic charge–discharge (GCD). Characterisation techniques validated the effective loading of Co₃O₄ and Fe₂O₃ nanoparticles within the NaAlg matrix, and revealed the efficient interfacial interactions, structural integrity, and electrochemical properties of the composites. GCD tests showed a very high specific capacitance of 571.43 F g⁻¹ at 1.2 A g⁻¹. The best-performing electrode produced a top energy density of 155.56 Wh kg⁻¹ at a power density of 2800 W kg⁻¹ and still showed around 91% capacitance retention after 2500 charging–discharging cycles with coulombic efficiency close to 100%. Boosted electrochemical performance is due to the synergistic effect of Co₃O₄-Fe₂O₃ nanoparticles that not only offer plenty of electroactive sites but also help in effective electron and ion transport within the polymer matrix. The results obtained here confirmed the capabilities of Co₃O₄-Fe₂O₃@NaAlg composite membranes as green and potent electrode materials for future supercapacitor devices. Full article

Electrospinning is a versatile technique for producing membranes composed of submicrometric fibers and possessing high porosity and a large surface-to-volume ratio. These properties make electrospun fiber mats attractive for many applications including filtration, biomedical materials, and sensing. While conventional set-ups readily generate randomly oriented nonwovens, many applications require precise control over fiber organization. Such control can be achieved by manipulating the charged jet and the residual charges retained by deposited fibers, both governed by the electric field that is intrinsic to the electrospinning process. This review examines strategies for electrostatic control of electrospun fiber mat morphology, organized around two principal mechanisms: control of the charged jet in-flight and control of the landing jet. Auxiliary electrode-assisted electrospinning, which aims to suppress or redirect the whipping instabilities, as well as gap-separated and structured collectors that exploit electrostatic template effects, are discussed. Particular attention is given to the underlying mechanisms. Collectively, these methods illustrate how tailoring the electric field allows for the production of membranes with complex, application-specific fiber morphologies. Full article

To realize the high-value valorization of cold-pressed walnut meal, walnut oligopeptides were fabricated via synchronous dual-enzyme hydrolysis combined with activated carbon decolorization and membrane separation purification. We optimized the overall preparation process and systematically characterized the products, including their amino acid profile, in vitro antioxidant capacity, cytoprotective effects against H₂O₂-triggered oxidative injury in PC12 cells, and regulatory activity toward acetylcholinesterase (AChE). The optimal hydrolysis conditions were identified as pH 10.0, total enzyme dosage of 11,000 U/g, a trypsin-to-alkaline protease ratio of 2.1:1, solid–liquid ratio of 1:26, temperature of 51 °C and reaction duration of 4 h, which produced a hydrolysis degree of 33.02%. The optimized decolorization parameters were pH 5.2, activated carbon dosage of 2.3%, treatment at 58 °C for 43 min, with a peptide recovery rate reaching 83.35%. Cold-pressed walnut meal is rich in glutamic acid, arginine and aspartic acid, which lay the molecular foundation for the bioactive properties of the derived oligopeptides. In vitro tests demonstrated that the oligopeptides possessed strong scavenging ability against hydroxyl, DPPH and superoxide anion radicals (clearance rates of 90.18%, 81.72% and 85.80%, respectively), and maintained 73.21% of antioxidant activity after simulated gastrointestinal digestion. Moreover, walnut oligopeptides at 0.8 mg/mL showed no cytotoxicity and afforded a 79.88% protective effect against oxidative damage. The peptides significantly boosted SOD and GSH-Px activities, lowered MDA accumulation, and strongly suppressed AChE activity, performing better than donepezil hydrochloride. This efficient, eco-friendly technique achieves high-value utilization of walnut processing by-products. The obtained oligopeptides possess great potential as natural antioxidants and neuroprotective ingredients for functional food development. Full article

The influence of chitosan (CS) molecular weight on the interfacial architecture of Ti₃C₂T_x MXene (MX)/chitosan composites (CS/MX) was investigated using complementary spectroscopic and microscopic techniques. Two commercial chitosans with distinct molecular weights and degrees of deacetylation (DD) were evaluated, CS-1 (91 kDa, 73.05% DD) and CS-2 (153 kDa, 69.52% DD). Ti₃C₂T_x MXene was synthesized by selective etching of Ti₃AlC₂ and characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), and Raman spectroscopy. XPS and Raman analyses provided evidence for successful MXene formation through a 45.4% reduction in surface aluminum content, a substantial increase in fluorine-containing surface terminations, and the emergence of the characteristic A₁g(Ti,C) Raman mode at ~200 cm⁻¹. Composite membranes containing different MXene loadings (MX-25, MX-50, and MX-75) were prepared by vacuum-assisted filtration and characterized. Morphological and spectroscopic analyses revealed that the lower-molecular-weight chitosan promoted more effective intercalation between MXene layers, resulting in expanded accordion-like structures and greater surface accessibility. In contrast, the higher-molecular-weight chitosan formed a thicker polymer coating that partially encapsulated the MXene sheets. ATR-FTIR, Raman, and XPS results demonstrated that CS-MX composite formation was governed by non-covalent interactions, primarily electrostatic attraction between protonated chitosan –NH₃⁺ groups and negatively charged MXene surface terminations, reinforced by hydrogen bonding. These findings demonstrate that chitosan molecular weight is a key design parameter governing the interfacial architecture and surface accessibility of Ti₃C₂T_x-based composites. Full article

The removal of five neonicotinoid insecticides, acetamiprid, chlothianidin, imidacloprid, thiacloprid, and thiamethoxam, was explored using various commercial ultrafiltration (MW, PT, and GK) and nanofiltration (HL) membranes provided by GE Osmonics Labstore. Several modification techniques have also been applied to one ultrafiltration membrane, including immersion in hot water, sodium hydroxide, and ethanol solutions, as well as interfacial polymerization with monomers such as polyethyleneimine and trimesoyl chloride, to improve micropollutant retention while maintaining adequate permeability. The results show that only immersion in ethanol (60% solution or absolute ethanol) improved membrane performance. Among the reagents and conditions tested for membrane surface modification via polymerization, the sequential application of polyethyleneimine, trimesoyl chloride, oven curing at 60 °C, followed by immersion in a glycerol solution was the most efficient. The optimal modified membrane was tested with real water matrices (two secondary effluents from wastewater treatment plants and a surface water sample) in which the neonicotinoids were dissolved. The modified ultrafiltration membrane showed higher retention (80–95%) than commercial ultrafiltration (15–60%) and levels similar to nanofiltration membranes (70–95%), demonstrating greater efficiency in retaining neonicotinoids under real water conditions, although the permeability was about half that of the commercial nanofiltration membrane. Therefore, this modification process is a promising alternative to commercial membranes for removing micropollutants from urban wastewater and should be considered. Full article

The growing demand for high-performance air filtration materials, coupled with increasing concerns over plastic waste accumulation, has accelerated interest in sustainable filtration technologies. Recycled polyethylene terephthalate (r-PET) has emerged as a promising feedstock for electrospun nanofibrous membranes due to the abundance, low cost, and sustainability of this plastic waste feedstock. The filtration performance of r-PET membranes has been demonstrated to be comparable to that of conventional virgin polymer filters. This review critically examines recent developments in electrospun r-PET nanofibrous membranes for air filtration applications, with particular emphasis on the role of membrane morphology in governing filtration performance. Unlike previous reviews that primarily summarize electrospinning techniques or recycled polymer applications, this review critically evaluates how membrane morphology—including fiber diameter, pore architecture, bead-on-string structures, and multilayer configurations—governs filtration performance in electrospun r-PET membranes. Evidence suggests that rational morphological engineering plays a more decisive role than polymer chemistry in overcoming the conventional filtration efficiency–pressure drop trade-off. Finally, future research opportunities in scalable manufacturing, environmentally benign processing, and artificial intelligence-assisted membrane design are discussed to support the development of next-generation sustainable air filtration media. Full article

The intensification of poultry production in Poland generates enormous quantities of excreta and associated biomass. While these constitute valuable sources of macro- and micronutrients, inadequate waste management leads to environmental pollution, nutrient leaching, and ammonia emissions. This paper analyses the fertilising potential of avian excreta, the legal provisions governing their application, and modern management technologies within the context of the circular economy. The study addresses two global threats—antimicrobial resistance (AMR) and the eutrophication of aquatic ecosystems—evaluating mitigation strategies and advanced biotechnological processing methods. Industrial farming turns excreta into a reservoir of active antibiotics, leading to the contamination of soils, waters, and crops. As a preventative strategy to reduce reliance on veterinary antibiotics—thereby indirectly mitigating the environmental dissemination of AMR—the dietary application of phytobiotics is highlighted. To counteract eutrophication, supplementing feed with exogenous microbial phytase plays a pivotal role, improving phytate phosphorus absorption and reducing its excretion by up to 50%. Furthermore, anaerobic co-digestion with carbon-rich substrates enhances methane yield, while advanced recovery systems (struvite precipitation, electrodialysis, bioelectrochemical concentration, and membrane techniques) show significant potential for safer nutrient concentration. An integrated technological approach to waste processing constitutes the foundation of sustainable agricultural production. Full article

Biofilms remain a major challenge in meat and poultry processing because conventional sanitation verification methods provide only indirect evidence of attached microbial communities. Emerging microbiological and sensor-based technologies offer new opportunities to improve biofilm detection by providing information on biofilm structure, cellular membrane integrity, composition, and spatial distribution. This review evaluates advanced imaging techniques, molecular assays, extracellular polymeric substance (EPS)-focused analyses, and real-time sensor platforms for their potential to strengthen risk-based biofilm monitoring in meat and poultry processing environments. Confocal and epifluorescence microscopy, scanning electron microscopy, optical coherence tomography, and in situ fluorescence imaging provide detailed visualization of biofilm architecture and viability, supporting validation of routine monitoring methods and assessment of sanitation practices. Quantitative PCR, digital PCR, amplicon sequencing, and metagenomics characterize biofilm communities, identify persistent microorganisms, and evaluate sanitation effectiveness, while EPS analyses of polysaccharides, proteins, extracellular DNA, and lipids indicate biofilm maturity and resilience. Electrochemical impedance, quartz crystal microbalance, surface acoustic wave sensors, and microfluidic platforms show promise for near-real-time detection of attached biomass. Collectively, these technologies provide a framework for more targeted, data-driven biofilm surveillance that can improve sanitation verification and reduce pathogen persistence in meat and poultry processing facilities. Full article

Nanofiltration membranes have emerged as a crucial class of pressure-driven separation materials, positioned between ultrafiltration and reverse osmosis in terms of selectivity, permeance, operating pressure, and energy consumption. Their ability to remove fine contaminants—including multivalent ions, organic micropollutants, dyes, and macromolecules—has made them essential in water and wastewater treatment, pharmaceutical processing, and various industrial applications. In spite of their growing relevance, the performance of polymeric nanofiltration membranes, such as polyamide, polysulfone, polyethersulfone, polyvinylidene fluoride, and polyimide, is still constrained by weak hydrophilicity and a strong susceptibility to fouling, which collectively decrease permeance, increase operational costs, and shorten membrane lifespan. In recent years, substantial research efforts have focused on designing and engineering the surface chemistry and structural characteristics of nanofiltration membranes to improve water permeance, reduce foulant adhesion, and improve long-term stability. This review provides a comprehensive and comparative assessment of the most recent modification techniques applied to polymer-based nanofiltration membranes. Strategies such as polymer blending, nanoparticle incorporation, physical surface coating, plasma treatment, chemical attachment, layer-by-layer assembly, and interfacial polymerization are critically examined with respect to their effectiveness and practical limitations supported by recent research examples. Special attention is given to how these modification methods affect membrane morphology, hydrophilicity, permeance, and antifouling properties. Eventually, the review highlights emerging ideas and forward-looking design directions that may guide the next generation of nanofiltration membranes toward higher efficiency, improved durability, and broader industrial applicability. Full article

Background: Subvalvular aortic stenosis (SAS) is an important cause of fixed left ventricular outflow tract obstruction and the second most common form of aortic stenosis. Although traditionally considered a congenital lesion, increasing evidence suggests that SAS often behaves as a progressive condition influenced by anatomical and hemodynamic factors. The disease may lead to significant complications, including left ventricular hypertrophy and progressive aortic regurgitation. Materials and Methods: A narrative review of the current literature was performed to summarize contemporary knowledge regarding the epidemiology, pathophysiology, clinical presentation, diagnostic evaluation, and management of subvalvular aortic stenosis. Relevant studies were identified through searches of major medical databases and were critically analyzed to provide an overview of current concepts and clinical practice. Results: Subvalvular aortic stenosis demonstrates considerable anatomical and clinical heterogeneity, ranging from discrete subaortic membranes to fibromuscular tunnel-type obstruction. The condition often progresses over time, with increasing LVOT gradients and a high incidence of associated aortic regurgitation. Echocardiography remains the primary diagnostic modality, while advanced imaging techniques provide additional anatomical detail and assist in surgical planning. Surgical resection remains the cornerstone of treatment when significant obstruction or related complications develop. Conclusions: Subvalvular aortic stenosis is a complex and progressive disease requiring careful imaging assessment and timely surgical management. Although surgical outcomes are generally excellent, recurrence and progressive aortic valve involvement remain important long-term considerations. Ongoing research aimed at improving risk stratification and optimizing surgical strategies may further enhance patient outcomes. Full article

This study investigates machine learning techniques for predicting the behavior of proton exchange membrane electrolyzers, which are vital for sustainable hydrogen production. This work addresses these challenges by integrating artificial neural networks to develop predictive models capable of capturing the performance of proton exchange membrane electrolyzers with high accuracy. This research utilizes a multi-layer perceptron network architecture, optimized through rigorous data preprocessing, parameter tuning, and error minimization strategies. The dataset used was based on published PEME numerical simulation datasets and encompasses key performance indicators, including stack voltage, water transport, and electrochemical reactions. The trained artificial neural networks models achieved mean squared error values of 3.66 × 10⁻⁵ and 9.75 × 10⁻⁶, with correlation coefficients of 0.99996 and 0.99958, demonstrating near-perfect predictive accuracy. A comparative benchmarking study against alternative regression algorithms revealed that the proposed MLP models significantly outperformed Gradient Boosting and Random Forest by several orders of magnitude, thereby establishing a higher level of persuasiveness and reliability for the developed framework. Average deviation rates of 0.11% and −0.01% further validated model reliability. The novelty of this work lies in its comprehensive approach, which goes beyond isolated metrics by addressing interactions across system parameters. This integrated framework enables enhanced prediction, control, and optimization of proton exchange membrane electrolyzer’s performance, setting a new benchmark for leveraging machine learning in hydrogen energy systems. These findings pave the way for scalable, cost-effective solutions to improve proton exchange membrane electrolyzers’ efficiency and operational reliability. Full article

Electrochemical parameter identification is crucial for evaluating the electrochemical processes in proton exchange membrane water electrolysis (PEMWE). Conventional characterization techniques-including polarization-curve fitting, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and current interruption (CI)-face significant limitations for rapid diagnostics under high-current dynamic operation, arising from constraints in instrument current rating, measurement time, zero-current control, and noise amplification in numerical differentiation. In this study, we present a simple current step (CS) method to accurately identify key electrochemical parameters and perform overpotential breakdown by using a simplified equivalent circuit model with a current source. To address the numerical instability in derivative calculation caused by sampling noise during voltage transient analysis, a physics-informed neural network (PINN) is introduced to enhance signal smoothness while guaranteeing physical consist ency. Compared with standard characterization, the proposed CS-PINN method demonstrates high accuracy, with an error of less than 2% in overpotential breakdown, less than 5.3% in ohmic resistance, and 2.8% in the Tafel slope (at 5 A/cm²). These results confirm that the CS-PINN method provides a fast, accurate, and equipment-friendly route for rapid electrochemical parameter identification in PEMWE. Full article

This paper presents a mathematical model to investigate how waves and currents interact with a flexible perforated floating membrane in finite water depth within the framework of linear wave theory. The perforated flexible membrane is modeled based on Darcy’s law and the one-dimensional string equation. The complex dispersion relation in the presence of current velocity is derived from the Green’s function technique using a fundamental source potential solution. The dispersion curve is analyzed by comparing the phase and group velocities for different water depths. Further, a physical model associated with the effect of current on a moored finite floating perforated flexible membrane integrated with a vertical wall is formulated. Then, the theoretical solution of a physical boundary value problem near a vertical rigid wall is obtained using the matching technique and the roots of the dispersion relation derived from the Green’s function technique. Numerical simulations are provided to verify the convergence of the series solution and the accuracy of the obtained analytical findings are evaluated against previously published analytical and experimental datasets. Further, several numerical results on the membrane deflection, hydrodynamic coefficients, and horizontal force on the wall for various structural parameters, mooring stiffness, and current velocities are analyzed. It is observed that the present analysis with this perforated membrane breakwater will be helpful to coastal and marine engineers to understand the influence of current velocity. Full article

Although ceramic materials exhibit excellent thermal stability, high melting points, and chemical inertness, their intrinsic brittleness restricts their application across various fields. To address this challenge, ceramic fibers possessing the flexibility and functionality demanded by advanced applications have emerged. This review provides an overview of recent progress in ceramic fibers, emphasizing four major spinning techniques, including melt spinning, electrospinning, solution blow spinning, and wet spinning, along with their underlying fabrication mechanisms and process–structure relationships. The fibrous architectures (including aerogels, textiles, and membranes) demonstrate exceptional performance in thermal protection, extreme environment, wave absorption, thermoelectric energy conversion, and wearable electronic textiles and high-temperature catalysis. Despite these advancements, challenges remain in scalable continuous production, long-term stability under realistic service conditions, multifunctional integration, and cost-effective sustainability. This review provides a roadmap for translating laboratory innovations into practical, large-scale deployment in aerospace, energy, and electronic systems. Full article

The global threat of multidrug-resistant infections requires new approaches for its management. A blend of polymethyl methacrylate (PMMA) and poly(ε-caprolactone) (PCL) electrospun nanofibrous membrane was utilised as a scaffold to sustain the release of three broad-spectrum antiseptics to combat multidrug-resistant (MDR) microorganisms. The scaffold was characterised by Fourier transform infrared spectroscopy, contact angle, and scanning electron microscopy. The latter revealed a random and smooth structure. The contact angle value of 81.8 ± 1.8 confirmed the hydrophilic nature of the scaffold, which is important for wound healing. The high surface-to-volume ratio of the scaffolds was utilised for loading benzoic acid (BA), methylparaben (MPB), and propylparaben (PPB) which were released during 72 h concentrations ranging between 0.20 and 0.8 mg mL⁻¹. The initial release of antiseptics was high and was then sustained for over 72 h. After 8 h, the burst release was 61.64 ± 4.11% for BA, 41.11 ± 2.98% for MPB and 34.32 ± 3.13% for PPB. The release profile of BA was superior to that of the MPB and PPB. The loaded scaffolds inhibited MDR-resistant methicillin-resistant Staphylococcus aureus, Escherichia coli and Candida albicans and were not cytotoxic to a fibroblast cell line. They inhibited their colonisation by the tested microorganisms to non-detectable counts or at least reduced microbial counts by at least 6–7 logs (p ≤ 0.001) for 72 h. Crystal violet techniques and electron microscopy confirmed colonisation inhibition. Because of their non-cytotoxicity and broad-spectrum antimicrobial activity, the antiseptic-loaded PMMA/PCL nanofibrous scaffolds could be utilised as wound dressings, particularly in non-healing wounds. Full article