Search Results (18,417)

Background/Objectives: Oseltamivir is a widely used antiviral agent indicated for the treatment of influenza and plays a central role in pandemic preparedness strategies. Although an extemporaneously prepared 15 mg/mL oral solution is recognized in formularies, preparing large volumes during a pandemic requires extended storage options. However, no stability studies are currently available for an oseltamivir 15 mg/mL oral solution stored under freezing and subsequent refrigerated conditions for the duration of a standard treatment. The aim of this study was to evaluate the physicochemical and microbiological stability of a 15 mg/mL oseltamivir oral solution prepared from the active pharmaceutical ingredient (API) and packaged in amber glass containers. Methods: The oral solution was formulated using oseltamivir phosphate API, sodium benzoate as a preservative, and purified water and then packaged in 125 mL Type II amber glass bottles, allowing for thermal expansion. The samples were stored at −20 ± 2 °C for up to 75 days, followed by refrigerated storage (5 ± 3 °C) after thawing for up to 10 days. Chemical stability was assessed using a validated HPLC method in accordance with ICH guidelines and was defined as 90–110% recovery of the initial concentration. Physical stability (color, pH, particulate matter, crystallization, and homogeneity) and microbiological stability were also evaluated. Results: The HPLC method demonstrated excellent linearity, precision, and accuracy. Oseltamivir concentrations remained within the predefined acceptance limits throughout the 75-day study period under freezing conditions, with no significant changes in pH, color, or particulate formation. After thawing, the drug concentration continued to remain fully stable and within the required limits for up to 10 days under refrigerated conditions. Despite the prolonged storage and phase changes, no significant changes in physical parameters were observed, and microbiological testing confirmed the absence of aerobic, anaerobic, and fungal microorganisms on the final day of the study. Conclusions: Oseltamivir 15 mg/mL oral solution in amber glass bottles is physicochemically and microbiologically stable for up to 85 days (75 days under frozen conditions plus 10 days under refrigeration after thawing). Full article

This critical assessment develops a mechanistic framework for plasma-engineered oxynitride thin films in photoelectrochemical (PEC) water splitting, moving beyond description to predictive understanding. Analyzing 30 peer-reviewed studies (2010–2025) via PRISMA 2020 and a structured reliability framework, we evaluate relationships between plasma conditions, film characteristics, and solar hydrogen generation. Results reveal that plasma power, gas composition, and substrate temperature collectively control nitrogen incorporation, crystallinity, and defect formation. Optimized plasma processing conditions were generally associated with improved photocurrent generation, hydrogen evolution performance, and operational stability relative to thermal synthesis routes across most of the reviewed studies, although the 30-study evidence base is still limited and the proposed power-domain classification should be treated as a preliminary framework requiring validation against additional studies. Mechanistic analysis indicates that moderate plasma energies provide sufficient activation for nitrogen incorporation while minimizing lattice damage and excessive defect formation. A unified conceptual framework is proposed relating plasma parameters, film properties, and PEC performance, providing mechanistic guidance for photoelectrode optimization and future process development. Quality assessment identifies that only 13.3% of studies provide high-confidence evidence (46.7% moderate, 40% low), with most lacking complete plasma diagnostics or long-term stability data, highlighting critical research gaps. The framework establishes that plasma engineering’s transformative potential lies in precise control over the composition–structure–property cascade, offering a reproducible route to high-performance oxynitride photoelectrodes for sustainable hydrogen production. Full article

Nb-containing TiAl alloys are among the most important lightweight intermetallics for high-temperature applications because they combine low density with useful strength, oxidation resistance and creep resistance. Their long-standing difficulty is equally clear: the ordered γ/α₂ matrix and lamellar hierarchy that support thermal stability also restrict plastic accommodation and manufacturing tolerance. This Perspective addresses a specific question: how can Nb–Ti–Al-related alloy design expand from stabilizing ordered TiAl matrices toward matrices and architectures that also enable scalable deformation and processing? The discussion is organized around three connected routes. High-Nb TiAl alloys established a durable service-stability platform; lamellar, colony, and orientation engineering then created deformation pathways within ordered matrices, and compositionally adjacent Zr–Ti–Nb–(Al)-concentrated BCC alloys introduced a different matrix-selection strategy in which chemical disorder and BCC stability are used to build processability at an earlier stage of design. These routes solve different parts of the same design problem rather than representing direct competitors. They indicate that future lightweight high-temperature alloys should be designed by linking composition selection, phase architecture, thermomechanical processing and environmental validation within a processability–stability framework. Full article

Extremophilic exopolysaccharides (EPSs) from extreme-environment microorganisms exhibit multifunctional and specific properties relevant to food, pharmaceutical, and environmental applications. This study reports the physicochemical characteristics of a novel EPS secreted by the marine actinobacterium Janibacter limosus (JlEPS) isolated from the Tyrrhenian Sea. The biopolymer was characterized for its molecular mass, monosaccharide composition, functional groups, rheological, and thermal behavior. JlEPS was found as an acidic heteropolysaccharide composed of eight sugar monomers. Neutral and acidic sugars predominate, with glucose (36.60 ± 0.46 mol%), rhamnose (23.62 ± 0.15 mol%), and galacturonic acid (16.54 ± 0.18 mol%). Amino sugars were also detected, including galactosamine (8.70 ± 0.01 mol%) and glucosamine (4.00 ± 0.10 mol%). Arabinose (7.8 ± 0.76 mol%), galactose (1.35 ± 0.01 mol%), and fucose (1.42 ± 0.06 mol%) were present in minor amounts. The average molecular weight (M_w) of the biopolymer was 1.60 × 10⁶ Da, with a polydispersity index of 1.022, indicating a relatively homogeneous population. FT-IR indicated uronic acids and glycosidic linkages, while TGA demonstrated stability up to 250 °C. JlEPS solutions behaved as pseudoplastic fluids, and the flow curves were fitted with the Carreau model (R² = 0.96–0.99). The zero-shear viscosity increased from 0.542 ± 0.187 Pa·s (0.5%) to (5.01 ± 0.91) × 10⁴ Pa·s, while the flow index decreased from 0.368 ± 0.032 to 0.100 ± 0.028, confirming strong pseudoplasticity and extensive molecular entanglements. JlEPS is a complex with a defined composition and high viscosity, supporting its potential for multiple applications. Full article

Natural bitumens are promising alternative hydrocarbon resources, but their high resin–asphaltene content and strong coke-forming tendency limit their efficient conversion into valuable liquid products. This study elucidates the molecular transformations of resin and asphaltene fractions during thermocatalytic upgrading of natural bitumens from the Beke and Munaily Mola deposits in West Kazakhstan. Cracking experiments were conducted at 450 °C for 60 min using thermal treatment, fly-ash-derived ferrospheres, and di-tert-butyl peroxide (DTBP) as a radical-generating additive. Elemental analysis, average-molecular-weight determination, and nuclear magnetic resonance (NMR) spectroscopy were combined with structural-group analysis to establish changes in the molecular architecture of the heavy fractions. Thermal cracking produced 68–74% liquid products, while DTBP increased the liquid yield to 70% for Beke bitumen and 87% for Munaily Mola bitumen and substantially suppressed coke formation. Cracking promoted extensive degradation of aliphatic and naphthenic fragments, dealkylation, cyclization, dehydrogenation, and aromatization, resulting in increased aromaticity and lower molecular weight of the asphaltenes. The average molecular weight of Beke asphaltenes decreased from approximately 2044 to 1003 amu in the presence of ferrospheres. Although ferrospheres enhanced asphaltene destruction, they increased coke formation under the investigated conditions. These findings demonstrate that radical stabilization is critical for directing heavy-component conversion toward liquid products and provide a molecular basis for optimizing catalytic upgrading of natural bitumen. Full article

The use of phase change materials (PCMs) in cementitious mortars is a promising strategy for passive thermal regulation and thermal energy storage (TES) in buildings, but its practical implementation remains constrained by PCM leakage and its effects on physical and mechanical performance. This study investigates the use of recycled clay brick waste as a dual-function component in eco-efficient mortars, serving as a partial replacement for fine aggregate and as a porous carrier for paraffin-based PCM. The experimental program comprised three stages: selection of an eco-efficient reference mortar, impregnation of recycled ceramic aggregates using thermal and vacuum-assisted procedures, and evaluation of PCM-modified mortars through fresh-state, physical, mechanical, thermophysical, direct thermal exposure, thermoregulation, and infrared thermography tests. Thermal impregnation at 15 wt% PCM provided the most favorable balance between PCM incorporation and stability against surface accumulation and mass loss and was selected for mortar production. Compared with REFeco, PCM incorporation reduced water absorption by approximately 10% and caused compressive and flexural strength losses below 10%. PCM15 exhibited the most favorable thermophysical balance, increasing volumetric specific heat by 14.9% and thermal inertia by 8.5%, while reducing thermal diffusivity by 10.8%. Under direct flame exposure, PCM25 produced the greatest thermal buffering effect, delaying the attainment of 200 °C on the rear face by approximately 4 min and reducing maximum estimated heat flux by approximately 16% relative to REFeco. Overall, recycled clay brick waste demonstrated potential as a PCM carrier for eco-efficient cementitious mortars with thermal energy storage functionality. Full article

The oil and gas industry has emerged as one of the largest consumers of polymer composites, with dissolvable polymers and composites representing one of the most significant technological advancements in this sector. These materials are essential for the manufacturing of high-performance tools such as hydraulic fracturing plugs, which must withstand extreme downhole conditions—temperatures of up to 250 °C and a pressure differential of up to 150 MPa—before dissolving rapidly in wellbore fluids to facilitate continuous production. Unlike traditional dissolvable polymers from the medical or consumer industries, which lack the required thermal stability, mechanical strength, and cost-effectiveness, these advanced materials must be formulated from readily available raw materials and manufactured on an industrial scale. Over the past two decades, significant progress has been made in the design and application of polymers like poly(glycolic acid), polyurethane, polyamide, epoxy, and isocyanate ester, developed through collaborative efforts between academia and industry. This review provides a comprehensive overview of the evolution of dissolvable polymer composites, covering material design, degradation mechanisms, manufacturing processes, and field applications. It concludes with insights into future development opportunities in the field. Full article

Ammonium dinitramide (ADN) is a high-energy green oxidizer with significant potential for use in solid propellants; however, its practical application is restricted by its strong hygroscopicity and low safety. In this study, morphology control and surface coating were simultaneously addressed by preparing ADN/PVA composite particles with different PVA contents by membrane emulsification. At a PVA content of 5%, the ADN/PVA composite microspheres exhibited favorable morphology and a high degree of sphericity, with no phase transition induced and the crystal structure well preserved. DSC results showed that the initial decomposition temperature of ADN/PVA increased by 21.88–26.50 °C compared to that of raw ADN, and the exothermic peak became narrower, indicating that the energy release of ADN was more concentrated and its thermal stability was significantly improved. Meanwhile, the impact sensitivity and friction sensitivity were reduced by 33.33% and 16.67%, respectively, relative to raw ADN, and the moisture absorption rate was reduced by 87.92%. Therefore, the ADN/PVA composite particles prepared by membrane emulsification exhibit excellent thermal stability and anti-hygroscopicity. Full article

High-entropy alloys (HEAs) and multi-principal-element alloys (MPEAs) provide broad compositional flexibility for regulating phase stability, microstructure, and properties. However, nominal composition and average phase constitution alone are insufficient to describe the actual material state formed during processing and service. This review summarizes the thermodynamic and diffusion-kinetic basis of phase formation and compares five representative fabrication routes, including mechanical alloying, vacuum melting, severe plastic deformation, magnetron sputtering, and additive manufacturing. Particular attention is given to the effects of processing history on grain structure, texture, elemental segregation, defects, phase constitution, and local chemical order. Computational methods and multiscale characterization techniques are also discussed in relation to the identification and interpretation of processing-dependent material states. Current studies indicate that alloys with identical nominal compositions can exhibit different microstructures and properties because of differences in thermal history, strain path, elemental redistribution, defect populations, and post-processing conditions. The review further examines strength and ductility, corrosion resistance, oxidation resistance, irradiation tolerance, and catalytic performance, with emphasis on the evolution of microstructure and surface state under service conditions. These results indicate that reliable evaluation of HEAs and MPEAs requires consideration of processing reproducibility, structural heterogeneity, and long-term stability rather than isolated peak properties. This processing–structure–service perspective provides a basis for more reliable comparison, selection, and engineering assessment of HEAs and MPEAs under application-relevant conditions. Future research should focus on reproducible fabrication, integration of computational prediction with experimental validation, multiscale assessment of structural evolution, long-term service performance, scalable processing, and sustainable alloy design. Full article

Thermosetting polymers offer excellent thermal stability, chemical resistance, and mechanical integrity, but their permanent covalent crosslinks limit recyclability and reprocessability. In this work, ESO-based vitrimer-like polyester networks were synthesized from epoxidized soybean oil (ESO) using tartaric, maleic, succinic, and tannic acids as catalyst-free curing agents. The influence of curing-agent structure on epoxy conversion, network homogeneity, thermal behavior, mechanical properties, chemical resistance, and reprocessing performance was systematically investigated. FTIR analysis indicated extensive epoxide ring opening and polyester network formation in all formulations. Tartaric and maleic acid systems exhibited stronger ester absorptions, higher gel content, and improved film uniformity, indicating more efficient network formation. The resulting materials showed good thermal stability, with degradation onset temperatures of 265–280 °C and maximum decomposition temperatures up to 400 °C. Mechanical performance strongly depended on acid structure: tannic acid produced the stiffest and strongest films, tartaric acid provided the best balance between strength and ductility, and succinic acid yielded less-uniform networks with reduced structural integrity. Reprocessing experiments demonstrated thermo-mechanical reprocessability consistent with vitrimer-like behavior in the tartaric- and maleic-acid-cured systems. These findings highlight curing-agent architecture as a key parameter for designing catalyst-free, renewable, and reprocessable ESO-based thermosets with tunable structure–property relationships. Full article

The importance of accurate and fast forecasting of wind speed is critical for guiding investment decisions, grid integration of wind power plants, and dispatch management. However, due to surface smoothness and the effects of thermal processes, wind-speed time series obtained from onshore and offshore sites have very statistically and dynamically distinct characteristics in terms of volatility, non-stationarity, autocorrelation, and noise components. This study proposes a Sinusoidal Representation Network (SIREN)-based framework to provide accurate, fast, and direct multi-horizon wind-speed forecasting for both onshore and offshore wind farms. Two datasets of onshore and offshore wind speeds, which have long durations and data continuity, are used to assess the performance of the suggested approach from very-short-term to long-term forecasting horizons. Both of the datasets use Savitzky–Golay filters and moving medians to reduce short-term noise and sudden spikes and winsorization and Hampel filters to limit the effect of outliers. Additionally, robust scaling is done to ensure stability of the scales of the variables, while log transformation is applied to counteract the problem of skewness and variation in the data distribution. The SIREN model is trained, validated, and tested independently for each forecast horizon, corresponding to times ranging from 5 min to 30 days. Ablation and sensitivity analyses are conducted to evaluate the effect of the parameters used in the model on forecast performance. In addition, comparative analyses incorporating traditional time series, and ML and DL techniques are conducted to more comprehensively evaluate the model’s performance. The obtained graphical and numerical results have revealed that the proposed SIREN approach is a highly accurate and computationally convenient alternative wind-speed forecasting method that can be flexibly adapted to different time resolutions and forecast horizons in both onshore and offshore systems. Full article

Mitigating structural failure and improving the fire safety of concrete infrastructure during severe thermal events depends critically on the high-temperature resilience of Portland cement paste. Given the increasing production of Portland blended cements, understanding their high-temperature behavior is crucial for ensuring the safety of building structures. This study investigates the effects of exposure to high temperatures (up to 1200 °C) on Portland cement pastes containing ground granulated blast furnace slag and quartz powder, focusing on their thermal stability and the chemical reactions occurring under these conditions. In situ X-ray diffraction (XRD) with a heating module was employed to observe real-time phase transformations as the temperature increased, supported by ex situ scanning electron microscopic analysis. The results showed changes in the mineralogical composition, with particular attention to the decomposition of calcium hydroxide and the formation of melilite above 900 °C. These transformations suggest thermal reactions between cement hydrate products (calcium silicates and aluminates) in the presence of slag and quartz powder. Mixtures containing quartz powder exhibited increased porosity and phase transformation shifts at lower temperatures, reflecting the combined effects of quartz addition, reduced reactive binder content, and an increased effective water-to-binder ratio. Notably, lower strength-grade cements containing fly ash (additional alumina source) show higher degrees of formation of calcium–aluminate silicate phases such as melilite upon heating. Compared to conventional studies, the novelty of this study lies in the use of an in situ experimental setup, which uniquely identifies the temperature thresholds of chemical changes and the formation of new phases such as melilite in cement–selected slag mixes, while also capturing their recrystallization upon cooling. Full article

We investigated the possibility of developing super austenitic stainless steel Avesta SMO 254 X1NiCrMoCuN20-18-7 (EN 10088-4) and austenitic stainless steel X15CrNiSi25-21 (EN 10095) coated with SiC, resulting in the obtainment of a Metal Matrix Composite (MMC) by additive manufacturing (AM) for the upgrade of nozzles for sulfur recovery thermal reactors. One layer of the MMC targets the outer surface of the part that is in constant contact with the flame and the area is subjected to high friction erosion. The Directed Energy Deposition Laser (DED-LB) method has made it possible to produce a high strength-to-weight ratio. The aim is to engage lower-cost material with similar thermal stability and durability in extreme conditions. The robotic unit used for the application allowed for computer control of the positioning, feeding of the SiC particles inside the shielding gas and deposition in the molten pool. After the solidification process, visual testing (VT) and ultrasonic testing (UT) were applied for non-destructive evaluation, checking for disbonding and subsurface imperfections. Then, samples were tested with microhardness measurements, bond strength, microcracking detection, porosity, interface zone assessments and microstructural analysis. The process achieved 0.4 to 0.7 KJ mm⁻¹ heat input with no defects and the intended nozzle surface passed UT and VT. Controlled parameters provided strong metallurgical bonding. Full article

Pyrolysis presents a promising approach to harness the bioenergy potential of biomass and promote waste valorisation within a circular economy framework. This study offers a detailed analysis of the thermal characteristics, reaction kinetics, and thermodynamic behaviour of two common waste biomasses in Nigeria, sawdust (SD) and sugarcane bagasse (SB), to assess their bioenergy potential using Thermogravimetric Analysis and the Coats-Redfern integral method. Proximate analyses revealed a high volatile matter content (over 82%) in both feedstocks. The pyrolysis parameters indicated a higher comprehensive pyrolysis (3.486 × 10⁻⁶, %³/°C³) and pyrolysis stability (1002.04%/C²) indices for SD, confirming its superior overall thermal reactivity. In contrast, SB demonstrated a superior devolatilisation index (5.0621 × 10⁻⁷%/C³) and a lower stability index (869.27%/C²), signifying an intense, concentrated eruption of volatile matter over a narrow temperature window. A multi-stage, segmented approach produced more accurate results than the general single-step model. The diffusion-based D6 model was most suitable for describing the drying and devolatilisation of SD, while the reaction-order R2 model best explained the devolatilisation process of SB. The thermodynamic analysis revealed that formation of the activated complexes for both SD and SB across all stages is strictly non-spontaneous and endothermic, with SD encountering a higher thermal barrier (∆H = 57.57 kJ/mol) than SB (∆H = 37.03 kJ/mol) during the process. These findings indicate that SD possesses properties favourable for fast pyrolysis processes aimed at bio-oil production, whereas SB exhibits characteristics that make it a promising feedstock for biochar-orientated pyrolysis. Further studies involving product yield and quality analyses are recommended to validate these potential applications. These findings provide essential information for designing effective, locally adapted bioenergy systems in Sub-Saharan Africa. Full article

Ultrasonic bonding offers a promising alternative to traditional sewing and other plastic bonding techniques, with several potential advantages. This paper comprehensively analyzes ultrasonic bond characteristics in PVC-coated hybrid textiles, prevalent in awnings and camping tents. Untreated samples were used as controls to compare the effects of ultrasonic bonding on various characteristics. Developed experimental designs were applied using a 12 mm welding width in a lapped seam, with carefully selected parametric levels to achieve higher bond strength based on preliminary test results. Mechanical properties (tensile, cyclic, and tear strength, including thickness reduction) were thoroughly examined to assess ultrasonic bond seam efficiency. The analysis covered thermal, chemical, morphological, and weight loss aspects before and after ultrasonic welding. Results showed that the weld seam tensile efficiency ranged from 68.27% to 96.13%, indicating enhanced durability. Cyclic efficiency exceeded 95%, tear efficiency surpassed 70%, and both treated and untreated samples showed strengths above standard thresholds. Thermal findings indicated a 3% increase in crystallinity after ultrasonic treatment, enhancing thermal stability with lower weight loss and causing shifts in glass transition and melting temperatures. FTIR spectra revealed that ultrasonic bonding had no significant impact on the material’s chemical properties. Morphological analysis identified pre-existing microvoids, with no significant increase in their number and/or size following ultrasonic treatment. Overall, the study demonstrates the efficacy of ultrasonic welding in improving the mechanical, chemical, and thermal properties of PVC-coated hybrid textiles, providing valuable insights for applications like awnings, camping tents, and roofing materials for short- and long-term use. Full article