Search Results (2,908)

In this work, we extracted silk fibroin (SF) via a tertiary solvent system (CaCl₂:Ethanol:H₂O) and then blended it with chitosan (CS) solution to construct microparticles using the water-in-oil-emulsion–diffusion method. For the mixture of SF/CS solution aqueous phase (W) was prepared at ratios of 4:0, 3:1, 1:1, 1:3, and 0:4, using ethyl acetate as the oil phase (O). After the microparticles were prepared, their morphology was examined using scanning electron microscopy (SEM). The optimal preparation conditions were determined to be a 1% (w/v) aqueous phase with a volume of 1 milliliter, 100 milliliters of oil phase, and a stirring speed of 700 rpm. The average microparticle size was 50–100 micrometers. ATR−FTIR spectra showed unique functional groups of SF and CS, as well as interactions between the two polymers. The results of the thermal property study using a TGA instrument showed that SF microparticles had a higher maximum decomposition temperature (T_d,max) than chitosan, and the blended microparticles’ T_d,max increased with the proportion of SF. Most microparticles exhibited a semi-crystalline polymer structure, with SF microparticles being the most hydrophobic, followed by blended microparticles and CS, respectively. Testing for absorption capacity, the SF microparticles were more effective at absorbing used engine oil than vegetable oil and chloroform, while CS microparticles showed the highest capacity for vegetable oil. The experimental results indicated that all SF/CS blended particles played an efficiency of absorption variable by ratios of SF or CS blended. This suggested that the prepared microparticles might be useful for oil/water separation application. Full article

Deep stormwater drainage tunnels are increasingly being used to mitigate urban flooding, but in-tunnel sediment deposition reduces their discharge capacity and complicates their maintenance. With direct field observation constrained, numerical simulation is essential, and river-based total sediment load formulas require reassessment for use in deep tunnels. The three-phase (air–water–sediment) CFD solver SedInterFoam is first validated against a benchmark open-channel suspended sediment experiment, and is then applied to a horseshoe tunnel under a fixed design discharge for multiple inlet sediment concentrations spanning urban stormwater conditions. Four classical formulas (Yang, Shen–Hung, Ackers–White, Engelund–Hansen) are evaluated at the CFD-resolved hydraulic state; Toffaleti is omitted because its zone-based formulation is incompatible with the partially filled horseshoe geometry. The CFD consistently shows persistent retention of a substantial fraction of the inlet sediment load, whereas the transport capacity-limited interpretation of the classical formulas predicts near-complete sediment throughput—indicating structural inadequacy for the dilute, supply-limited regime typical of urban stormwater. A Universal Soil Loss Equation (USLE)-style dimensionless deposition formula is therefore proposed, with inlet sediment loading as the explicit independent variable and a tunnel correction factor 𝐾_tunnel absorbing the geometric, hydraulic, and sediment variations. Its regression yields an almost linear scaling and a nearly constant deposition ratio, while analysis of the internal flow and concentration fields shows that the retained sediment is strongly concentrated near the bed and that near-bed turbulent mixing weakens moderately with a rising inlet concentration. While calibrated for a single non-cohesive settleable sand fraction, the framework provides a transferable basis for inlet-loading-dependent deposition prediction in deep stormwater drainage tunnels, and subsequent extension of 𝐾_tunnel to broader sediment conditions with field-based validation is expected to enable maintenance planning, dredging volume estimation, and sediment retention risk assessment. Full article

Achieving a favorable synergy of strength, ductility, and toughness is a critical challenge for expanding the engineering applications of titanium alloys. In this work, a medium-strength and high-toughness novel Ti-Al-Mo-V-Cr-Sn-Zr (named Ti62F) titanium alloy in the form of a Φ400 mm bar was adopted to systematically investigate the regulation behavior of double annealing on its microstructure and mechanical properties, and quantitative correlations between microstructural parameters and macroscopic properties were established. Increasing the cooling rate during the first annealing stage (air cooling, force air cooling and water quenching) significantly refined the secondary α (α_s) phase and reduced the volume fraction and size of the primary α (α_p) phase, leading to an increase in the ultimate tensile strength of the alloy from 1077 MPa to 1229 MPa. However, the impact-absorbed energy decreased from 51.5 J to 23.3 J. When the second annealing temperature was varied within the range of 625–675 °C, the ultimate tensile strength fluctuated slightly and the impact toughness increased moderately. Equiaxed α_p phase and relatively thick α_s can induce multiple crack deflections, prolong the crack propagation path and enhance energy absorption. Dislocations are mainly piled up at α/β phase boundaries, triggering void nucleation and growth, which dominate the ductility and toughness levels. Tensile twinning acts only as an auxiliary deformation mechanism and contributes limitedly to toughness. After heat treatment under the optimized schedule of 880 °C/2 h/AC + 650 °C/4 h/AC, the Ti62F alloy exhibits a superior strength–toughness balance compared with conventional medium-strength titanium alloys such as TA15, TC4, and TC4-DT. The findings can provide a heat treatment basis for microstructural regulation of large-size Ti62F bars and their engineering applications in aerospace structural components. Full article

This study investigates the influence of organic matter properties in surface waters on the efficiency of single- and two-stage coagulation processes in drinking water treatment plants. The research was conducted at three treatment plants supplied by different surface water sources over a 15-month monitoring period. The analyzed parameters included total and dissolved organic carbon (TOC and DOC), biodegradable dissolved organic carbon (BDOC), water color, UV absorbance, zeta potential, and molecular weight distribution of organic substances. The results showed that coagulation efficiency depends strongly on both the concentration and the molecular characteristics of organic matter. The highest removal efficiency was observed for high-molecular-weight fractions (>2.0 kDa), mainly humic substances, whereas low-molecular-weight compounds were removed less effectively. The study also demonstrated that surrogate spectrophotometric parameters, particularly UV₂₅₄ absorbance and color at 410 nm, can be used to monitor and optimize the coagulation process. Given the increasing frequency of extreme climate events and rapid shifts in raw water quality, optimizing single- and two-stage coagulation configurations has become an urgent operational necessity. This work provides a novel direct linkage between simple spectrophotometric indexes and precise chromatographic molecular ranges, delivering an immediate, high-impact predictive tool for real-time dosage optimization in water treatment engineering. Full article

In this work, ZnO nanoparticles were synthesized via a plant-mediated green route using Prosopis tamaulipana extract as a reducing and stabilizing agent and subsequently modified with silver to obtain Ag-modified ZnO powders. Structural and morphological characterization techniques confirmed the formation of nanocrystalline ZnO with a hexagonal wurtzite structure, submicrometric agglomerates composed of nanosized primary particles and a high degree of phase purity, indicating the effectiveness of the synthesis approach. The photocatalytic performance of the Ag-modified ZnO materials was evaluated under natural solar irradiation using methylene blue as a model organic contaminant in aqueous solution. Visual observations, together with absorbance, temperature and electrical conductivity measurements, demonstrated an effective and progressive degradation of the dye over a 5 h irradiation period. The observed increase in electrical conductivity under illumination was associated with enhanced charge carrier generation and improved separation efficiency, as well as the formation of reactive oxygen species, promoted by the presence of Ag as an electron sink. These results confirm that green-synthesized Ag-modified ZnO nanoparticles exhibit enhanced photocatalytic activity and are promising multifunctional materials for sustainable water sanitation applications. Full article

This study investigated the potential of microbial-assisted phytoremediation using Eichhornia crassipes (water hyacinth) to reduce heavy metal and salinity pollution in produced water collected from Aadi Oil Field in Gujar Khan, Pakistan. Produced water was analyzed for physicochemical parameters and heavy metal content using Inductively Coupled Plasma–Optical Emission Spectrometry (ICP-OES) to establish baseline data. E. crassipes plants augmented with indigenous, contaminant-tolerant microbial isolates were employed in a 15-day laboratory experiment. The results showed a resilient growth response, with plant height increasing to approximately 11–15 cm and root length extending up to 10–13 cm across treatments. Biomass also improved, with wet weights reaching 21–24 g from an initial 20 g. The treatment effectively reduced key physicochemical parameters: pH was stabilized from an initial alkaline value of 9.14 to near-neutral values (7.0–7.5), and total dissolved solids (TDSs) were reduced by approximately 50%. Heavy metal removal rates varied, with the highest efficiency of 79.2% for Silver (Ag) and the lowest (18.5%) for Mercury (Hg) This study demonstrates that E. crassipes actively participated in phytoremediation by absorbing and accumulating heavy metals and reducing salinity. The association with contaminant-tolerant microbes appeared to enhance the plant’s tolerance and overall treatment efficacy, indicating that plant–microbe interactions offer a sustainable strategy for the treatment of produced water. Full article

A surprising tribocatalytic capability has been discovered for Si single crystals to convert mechanical energy into chemical energy for organic dye degradation recently. In this study, their tribocatalytic capability has been explored for converting mechanical energy into chemical energy of water splitting. In glass reactors with Si single crystals coated on the bottoms and with H₂O and N₂ enclosed, Al₂O₃ nanoparticles, TiO₂ nanoparticles, and NiO particles were stimulated through magnetic stirring using home-made PTFE magnetic rotary disks separately. For Al₂O₃ nanoparticles, as much as 14,330 and 41,964 ppm H₂ were produced after 1 and 3 h of 400 rpm magnetic stirring, respectively, much higher than those obtained for TiO₂ and NiO, and for Al₂O₃ nanoparticles in glass-bottomed reactors as well. The tribocatalytic production of H₂ was further explored with respect to NaCl addition to H₂O and p/n doping in Si, with negative effects observed for them all. Photoluminescence spectroscopy revealed continuous generation of hydroxyl radicals in the course of magnetic stirring, which supports a tribocatalytic mechanism based on the excitation of electron–hole pairs in Si single crystals through mechanical energy absorbed through friction. These findings suggest a great potential for narrow-band semiconductors to utilize mechanical energy through friction to carry out important chemical reactions. Full article

Food loss and waste—FLW—represent a critical global challenge, primarily across postharvest handling, storage, and distribution. Shelf life limitations—arising from microbial activity and proliferation, physicochemical degradation, and environmental interactions—are major contributors to these losses. Intrinsic factors such as pH, water activity, nutrient composition, and biological structure interact with extrinsic conditions including temperature, humidity, gaseous atmosphere, and light exposure, ultimately leading to quality deterioration and consumer rejection. A comprehensive insight into these mechanisms is essential to improve preservation strategies and reduce FLW. This review critically examines the determinants of food shelf life and highlights the strategic role of innovative packaging technologies in mitigating degradation pathways. Particular emphasis is placed on active packaging systems, including commonly studied technologies such as oxygen and ethylene scavengers, carbon dioxide emitters and absorbers, moisture regulators, antimicrobial- and antioxidant-releasing materials, and flavor and odor control systems. Their mechanisms of action, material design, performance factors, and practical limitations are discussed. Innovative packaging technologies actively modulate spoilage, extend shelf life, and preserve both sensory and nutritional quality, moving beyond conventional passive barriers. When combined with optimized supply chains and sustainable materials, these systems can strengthen food system stability and advance global sustainability goals. Full article

This study investigates the bio-inspired photocatalytic degradation of humic acids using TiO₂-functionalized clinoptilolite (C–TiO₂) and Ag-doped TiO₂ (C–TiO₂/Ag) under UV irradiation. TiO₂ acts as an artificial analogue of naturally occurring photoactive mineral phases, while clinoptilolite provides a biomimetic scaffold mimicking mineral–organic interfaces. Ag doping enhances charge separation and promotes reactive oxygen species formation, accelerating degradation. The effects of pH and catalyst composition were evaluated over a range of conditions, including the native pH of the humic solution. Degradation was monitored via changes in UV₂₅₄ absorbance, VIS₄₃₆ absorbance, and COD values, revealing a multistage pathway: rapid decolorization of chromophoric groups, slower breakdown of aromatic structures, and final mineralization. Acidic conditions further enhanced performance through increased adsorption and ROS (reactive oxygen species) generation, while measurable activity persisted at near-natural pH values. Kinetic analysis indicated pseudo-first-order behavior, with the highest apparent rate constants obtained for VIS436 removal under C–TiO₂/Ag at pH 3 (k = 0.0166 min⁻¹), followed by COD₁ (k = 0.0190 min⁻¹), confirming faster oxidation of labile fractions and slower mineralization of recalcitrant intermediates. Therefore, the results demonstrate that semiconductor–mineral hybrid systems can serve as biomimetic platforms that reproduce and accelerate natural self-purification processes, providing mechanistic insights into nature-inspired pathways for water treatment. Full article

The adsorption of H₂S impurity in the gas flow on carbon adsorbents produced from coconut shells and sugarcane bagasse was studied. The runs were carried out in pulse mode. An original chromatographic method for determining the degree of H₂S absorption on carbon adsorbents has been developed, which makes it possible to determine the amount of absorbed H₂S in air and water environments. The results obtained show that the successive treatment of carbon adsorbents first with a solution of a strong oxidizer (HNO₃, KMnO₄) and then, after washing, with an alkali solution (KOH) leads to a sharp increase in the amount of H₂S adsorbed. The efficiency of H₂S absorption on the obtained adsorbent reaches 85.5%, which corresponds to 27.7 mg/g H₂S and is comparable to the results obtained on commercial coconut carbon (CAU). The data allow one to conclude that the rise in the H₂S adsorption on the carbon sorbents studied can be due to the increase in the micropores’ volume in the activated carbon, as well as the formation of surface functional groups containing an alkali metal (i.e., C-OK, C-COOK) that promotes irreversible chemisorption of H₂S impurity on the carbon adsorbent. The absorption of H₂S occurs through the chemisorption mechanism, which is confirmed by IR spectroscopy data. Full article

Millions of tons of lignin waste are generated annually by the pulp and paper industries and by biofuel production. Current strategies for lignin valorization, biochars and hydrogels, often rely on time-costly and pollutant-generating processes and therefore fail to meet sustainability requirements nor are economically efficient. In this work, we address the challenge of transforming lignin into a valued-added material. We propose using microwave processing to convert lignin into a functional material that is carbon-rich, structured, hydrophilic, and highly porous. Unlike conventional methods, this process is rapid, occurring in approximately 30 s under normal conditions. It induces graphitization and up to a sixfold volumetric expansion of the lignin precursor sample, leading to the formation of a stable carbon material with high porosity in the form of capsules. The resulting material exhibits strong hydrophilicity, absorbing up to 90% of its volume in water within minutes while enabling controlled release over periods of up to 24 h. This unique combination of ultrafast processing, high water uptake capacity, and controlled-release performance positions the material as a promising alternative to the valorization of lignin. Its properties make it particularly suitable for water management applications in agriculture and urban environments. Full article

As the power density of office computing clusters rises to 200–250 W per chip, the substantial heat generated during operation not only impairs chip performance and shortens lifespan but also compels heating, ventilation, and air conditioning (HVAC) systems to operate at high loads. This increases energy consumption by 30–40% and causes indoor temperature fluctuations that reduce office workers’ comfort. Targeting centralized thermal management for such clusters, this study proposes a hybrid cooling strategy integrating outdoor natural cold air (as a continuous heat sink) with phase change materials (PCMs, for transient heat peak absorption). Six adjustable heating plates (power range: 50–250 W per unit, simulating 7 nm office chips) mimicked heat dissipation in a six-chip cluster. Latent heat storage (LHS) units served as passive cooling, with fan coils as auxiliary for natural/forced convection. By using PCMs (melting point: 48 °C) to absorb transient peaks and coils to utilize outdoor cold air, the system maintained circulating water at approximately 60 °C (steady-state equilibrium temperature under full-load conditions) and kept chip temperatures below 80 °C (industrial safety threshold). The hybrid system reduced combined pump and fan power to 125 W, achieving 75% energy savings compared to the HVAC system (500 W) and 40% savings compared to using only natural cold air (210 W pump and fan power). Positive pressure in the outdoor unit (increasing coil air velocity by 1.2 m/s relative to natural convection) further improved heat dissipation efficiency by 15%. Finally, this study quantifies the influence of PCM thermal conductivity and filling mass on the system’s temperature control performance through numerical simulations, providing direct evidence for parameter design of LHS units. Full article

Hyperloop transport operates in a low-pressure environment in which convective heat transfer is strongly limited, making conventional air-based cooling ineffective. One promising thermal management approach is therefore to absorb the waste heat generated during travel in a thermal energy storage (TES) system and dissipate it during stops. In this context, latent heat storage based on water–ice systems is particularly attractive because of its high energy density and nearly constant-temperature heat absorption. However, experimental validation of such systems beyond laboratory scale is still lacking. This study therefore investigated a large-scale direct contact latent heat storage (DCLHS) system for Hyperloop thermal management, using water as heat transfer fluid and ice as phase change material. The system was evaluated for two ice morphologies, crushed ice and ice block, under both constant and time-variant cooling power profiles representative of Hyperloop operation. The objective was to assess thermal performance, exergy efficiency, and hydraulic stability at application-relevant scale, and to identify morphology-dependent trade-offs relevant for system integration. The results show that the large-scale system can operate reliably under dynamic loads and that upscaling leads to smoother thermal behavior and reduced boundary effects. Crushed ice demonstrated superior thermal responsiveness, maintaining outlet temperatures close to the phase change temperature and achieving exergy efficiencies up to 0.72 at cooling powers up to 3.8 kW while enabling stable operation at 15 °C. In contrast, the ice block configuration provided higher volumetric energy density but exhibited delayed thermal response and required substantially higher mass flow rates, which limited operation to approximately 25 °C and reduced exergy efficiency to 0.03–0.35. Overall, the results show that large-scale DCLHS is a feasible option for Hyperloop thermal management, while also revealing that system behavior at larger scale is strongly influenced by storage morphology. Full article

Porphyra sensu lato is a promising source of natural photoprotective and antioxidant compounds for cosmeceutical applications. This study evaluated the geographical and temporal variability of bioactive compounds in Porphyra and Pyropia spp. from Chile and Spain and assessed their applicability in topical photoprotective formulations. Antioxidant capacity, soluble polyphenols, phycobiliproteins, and mycosporine-like amino acids (MAAs) were quantified in different species, collection sites, and sampling periods. In parallel, selected Pyropia elongata extracts were incorporated into water-in-oil creams, alone or combined with vegetable oils and physical UV filters, and in vitro SPF/UVAPF values were determined using the PMMA plate transmittance method. Marked variability was observed among species, sites, and collection dates. In P. elongata, total MAAs ranged approximately from 3 to 6 mg.g⁻¹ DW, while porphyra-334 was the dominant MAA, accounting for about 70–100% of total MAAs across samples. A positive correlation was found between soluble polyphenol concentration and ABTS antioxidant activity. In the formulations, Pyropia extracts increased absorbance mainly in the UVB–UVA range and improved SPF and UVA-related protection, particularly when combined with karanja and calophyll oils and physical filters. These results support Porphyra sensu lato biomass as a flexible natural reservoir for developing sustainable bio-based photoprotective products. Full article

Carbon dioxide emissions are a major concern for coal-fired power plants. A capture and utilization method is highly demanded. The wastewater generated by a power plant contains a high concentration of Na⁺. Using wastewater salts to absorb carbon dioxide for sodium carbonate production is a promising strategy, as it can achieve carbon capture and utilization and wastewater resource utilization. However, the salt concentration in raw wastewater from coal-fired power plants is generally insufficient to achieve sustainable carbon capture; thus, concentrating the Na⁺ in the wastewater is key. In this study, desulfurization wastewater was investigated as a source of salts. The reverse osmosis (RO) process was selected for salt concentration. As wastewater is significantly complex and unsuitable for direct RO treatment, pre-treatment was conducted. For chemical oxygen demand (COD) removal, Fenton oxidation (49.7%) and electrochemical oxidation (49.3%) achieved better results than microelectrolysis (25.3%). Precipitation showed a strong ability to remove hardness. The removal efficiencies for Mg²⁺ and Ca²⁺ were 99.9% and 99.8%, respectively. It gave 8.6% COD removal as well. Additionally, 89.8% of ammonia was removed by stripping. To further decrease the pollutant concentrations, activated carbon was used for adsorption. RO then concentrated the pre-treated wastewater after nanofiltration. The final level of NaCl was 40.4 g/L after concentration. This was lower than that required to concentrate the water, which contained only NaCl. This is due to the presence of impurities left in the wastewater after pre-treatment. The study reveals that pre-treatment is essential to achieve the desired NaCl concentration in RO with the ultimate goal of CO₂ capture. Full article