Search Results (547)

Mineral oil hydrocarbons (MOH), comprising saturated (MOSH) and aromatic (MOAH) compounds, are ubiquitous lipophilic contaminants. This review critically examines their occurrence, toxicology, analysis, contamination sources, and mitigation strategies in the olive oil sector. Emphasis is placed on analytical evolution, highlighting online LC-GC-FID and the EN ISO 20122:2024 standard, including advances in saponification and epoxidation to minimize biogenic interferences. Monitoring data reveal that virgin olive oils from the market can sometimes exceed the 2.0 mg/kg limit for the MOAH. Ten times higher levels are usually found in olive pomace oils (OPOs). In OPO, solvent extraction causes a significant reconcentration of hydrocarbons remaining on the solid matter after physical extraction and accumulating during the open-air storage of pomace. Conversely, for virgin oils, contamination can occur at multiple points along the supply chain, but harvesting emerged as the most important critical step, often due to accidental contact with lubricants, greases, or hydraulic fluids. Post-milling operations may also contribute to contamination. Mitigation strategies rely on Good Agricultural and Manufacturing Practices, focusing on the systematic replacement of technical-grade lubricants with food-grade alternatives. Additionally, olive washing can reduce initial MOSH content, while refining further lowers levels, particularly in lighter fractions. Full article

The minimisation of substances of concern in packaging is a key objective of the European Union’s Packaging and Packaging Waste Regulation (PPWR), complementing existing legislation governing the safety of food contact materials. Per- and polyfluoroalkyl substances (PFAS) present particular challenges due to their persistence, chemical diversity, and documented use in certain food contact materials. Article 5 of the PPWR requires packaging to be designed and manufactured to minimise such substances throughout the life cycle. This study develops a structured, material-based PFAS risk matrix to support compliance screening for food packaging under Article 5. The approach combines scientific evidence on PFAS occurrence, functional applications, and analytical detection with material classification systems used in recyclability assessments. Packaging materials are categorised by their likelihood of PFAS relevance, enabling proportionate prioritisation of efforts. Application of the matrix shows that fibre-based materials with grease- or water-resistant treatments exhibit higher relevance than glass, untreated paper, or polyethylene terephthalate (PET). The framework also clarifies the role of total fluorine (TF) and extractable organic fluorine (EOF) as supportive, material-specific indicators rather than standalone compliance metrics. By integrating PFAS considerations into design, sourcing, and portfolio management, the framework promotes proactive chemical risk governance aligned with circular economy objectives. Full article

Wastewater treatment through phytoremediation with plants reduces contaminants to acceptable levels as established by the Environmental Quality Standards (EQS) of Peru. This study evaluated the efficiency of Azolla filiculoides Lam. plants from the Huayllaspanca Colored Wetland (Laguna Coloreado) in the phytoremediation of wastewater from Huamancaca Chico, Chupaca Province, Junín Region, Peru. A pre-test and post-test experimental design was used. Glass aquariums of dimensions 54 × 20 × 21.3 cm were set up, and 28 g of phytoremediation plant samples were planted in 20 L of wastewater over a 28-day period. The main results for contaminant removal efficiency were as follows: clear and odorless water, total dissolved solids (40.27%), electrical conductivity (41.07%), turbidity 98.51%, oils and greases (>90.7%), BOD₅ (95.55%), COD (95.04%), and ammonia nitrogen (95.77%). The final removal of fecal coliforms and Escherichia coli from wastewater using A. filiculoides was 99.9%, with post-treatment averages (11.6 MPN/100 mL and 2 MPN/100 mL, respectively) significantly lower than their respective Environmental Quality Standards (EQS) (1000 MPN/100 mL) (p < 0.05). In conclusion, Azolla filiculoides Lam. is an effective macrophyte for improving the physical, chemical, and microbiological parameters of wastewater and removes contaminants. Full article

The packaging sector presents a significant sustainability challenge, particularly due to the prevalence of plastic packaging. There is a growing interest in sustainable packaging alternatives. The main challenge is to develop packaging with comparable and competitive characteristics. In this context, this manuscript aims to evaluate the performance of lignin-based polyurethane applied as a coating on recycled linerboard. Industrial softwood kraft lignin was fully characterized in terms of purity, functional groups (FTIR and ³¹P NMR) and molecular weight (GPC). Aiming at coating applications, the lignin sample was solubilized in dimethyl sulfoxide (DMSO) and used as a polyol substitute in the reaction, replacing polyethylene glycol (PEG) at levels of 70%, 80%, and 90%. Subsequently, hexamethylene diisocyanate (HDI) was added to initiate polyurethane formation. After polymerization, the coating was applied in multiple layers onto the linerboard paper. Regarding water resistance, all applications demonstrated effectiveness. The lignin-based polyurethane coating improved the Cobb1800 with reductions in the range of 1147.4 to 1155.8 g/m² compared to the uncoated paper. Water vapor permeability was reduced by more than 94%. In the evaluation of oil resistance, samples with three layers and 90% lignin replacement performed particularly well, achieving a high value in a kit test for oil and grease (kit test number 12). These results highlight a promising approach to paper-based packaging, with potential applications across a wide range of products. Full article

Conventional thermoelectric generators (TEGs) suffer from thermal resistance introduced by ceramic substrates and thermal interface materials, which limits the achievable temperature gradient across the junctions and reduces conversion efficiency. To overcome this limitation, a pin-fin integrated thermoelectric device (iTED) is proposed, in which the hot-side heat exchanger is incorporated directly into the hot-side interconnector, eliminating the ceramic and associated greases. An explicitly coupled thermal-fluid-electric finite-volume model is developed in ANSYS Fluent’s user-defined scalar (UDS) environment to quantify the simultaneous thermal-fluid-electric behavior of the iTED for inlet temperatures of 350 $\le T_{\mathrm{in}}\mathrm{K}\le$ 650, Reynolds numbers of 3000 $\le \mathrm{Re}\le$ 15,000, and load resistances ranging from 0.01 to ${10}^6$% of the internal device resistance ($R_{\mathrm{int}}$), for a fixed cold-side temperature of 300 K. The model is validated against established tube-bank correlations (2.2% agreement in pumping power) and a one-dimensional Explicit Thomson Model (1.2–6.9% agreement across all electrical system response quantities). Compared with an equivalently sized conventional TEG, the iTED achieves a 4.6-fold higher maximum power output (23.9 [W] vs. 5.2 [W] at Re = 15,000), a 2.8-fold higher thermal conversion efficiency (8.1% vs. 2.9%), and a 4.8-fold higher performance index (7.8 [-] vs. 1.6 [-] at Re = 3000), all at $T_{\mathrm{in}}$ = 650 K. A performance index analysis reveals that lower Reynolds numbers and higher inlet temperatures maximize the net power benefit, delineating the operational envelope in which the iTED produces more electrical power than is needed for fluid pumping. These findings demonstrate that device-level restructuring—specifically, the elimination of interfacial thermal resistance via integrated pin-fin heat exchangers—can yield performance improvements comparable to or exceeding those achievable through material advances alone. Full article

The present study investigates the influence of low temperatures on the starting torque, viscous friction, and power intensity of a precision cycloidal reducer TwinSpin TS 140-115-E-P19-0583. Two types of plastic greases with differing viscosities were compared in the experiment: Castrol TT-1 (low-viscosity, optimised for low-temperature) and Vigo RE-0 (higher viscosity, designated for greater loads). The measurements were taken in a climate chamber in the temperature ranging from +24 °C to −20 °C in the mode accounting for no external load. The results have shown that Castrol TT-1 maintains its beneficial rheological properties at as low as −20 °C, which is manifested in a low starting torque (~0.30 Nm) and low power intensity (~0.33 kW). On the contrary, Vigo RE-0 shows a significant increase in friction: at −20 °C, the starting torque is 1.0–1.1 Nm and the power intensity of the operation increases to consume more than 1.5 kW. The correct choice of lubricant is a critical factor for reliable cold-start behaviour under no-load, internal-loss-dominated conditions. This study provides a rare experimentally verified low-temperature assessment of starting torque, viscous friction, and power intensity in fully assembled TwinSpin precision cycloidal reducers lubricated with greases of markedly different viscosity classes, addressing an important gap in the existing literature. Full article

Cellulose fibers offer renewable sourcing and an established recycling infrastructure for food packaging applications. Their hydroxyl groups bind water strongly, which causes dimensional instability and compromises barrier performance at elevated humidity. Chemical modification targets this limitation through controlled changes to hydroxyl reactivity, surface charge, and interfiber hydrogen bonding. This review covers four principal covalent modification routes: esterification, etherification, phosphorylation, and oxidative functionalization. The spatial localization of functional groups—surface-enriched versus bulk modification—is treated as a cross-cutting analytical parameter governing the translation of molecular chemistry into barrier performance, mechanical behavior, and recyclability. We emphasize how molecular parameters (degree of substitution (DS), charge density, and the spatial distribution of functional groups) translate into barrier properties, mechanical performance, and grease resistance under realistic service conditions. Two practical constraints define the design space. Bulk modifications that penetrate the fiber wall can release reagents or by-products into food (non-intentionally added substances, NIASs), whereas surface-confined chemistry reduces this risk substantially. Modifications that resist repulping or introduce persistent contaminants damage recyclability. Life cycle impacts often derive more from processing steps (mechanical fibrillation, solvent use, and multi-stage washing) than from feedstock selection. We focus on three deployment-relevant outcomes: performance retention above 75% relative humidity, migration risk under food contact regulations, and compatibility with industrial fiber recycling. The aim is to identify strategies that can move from laboratory demonstration to production-scale implementation. Full article

Oily substances (oils, greases, lubricants, etc.) are among the most persistent pollutants for water. They mix with water to form emulsions that contaminate large volumes. Therefore, this project evaluated the use of porous systems (polyurethane foam) modified with polydimethylsiloxane-modified silica (SiO₂/DMS) hybrid ceramics as filtration membranes at the laboratory scale for vegetable oil. The polyurethane foam was modified using sol solutions with various SiO₂/PDMS ratios obtained via the sol–gel method. Tetraethyl-orthosilicate (TEOS) was used as the silica precursor. Three different polydimethylsiloxane chains were employed as the organic fragment: polydimethylsiloxane hydroxyl terminated (DMS-CH₃), aminopropyl-terminated polydimethylsiloxane (DMS-N), and copolymer polydiphenylsiloxane-polydimethylsiloxane hydroxyl terminated (PDS). The siloxane chain was added at a concentration of 20–40% w/w. The modification of the porous system was determined using different characterization techniques, including infrared spectroscopy, which was used to observe the main functional groups. Optical microscopy and SEM were used to identify the hybrid ceramic deposited into the pore structure of the polyurethane sponge. Contact angle measurements revealed the hydrophobic character of the modified material. The removal capacity was evaluated by using vegetable oil as a representative oily contaminant, with values ranging from 43.42 to 96.78 g of oil per gram of adsorbent. In the case of gasoline, removal capacities between 27 and 54 g were observed. This study demonstrated the influence of hydrophobicity on vegetable oil removal, confirming that higher hydrophobicity leads to greater adsorption capacity. Nevertheless, the use of a viscous contaminant introduced challenges in the extraction process from the PS/SiO₂-DMS system. Despite this limitation, the material maintained adequate removal performance for up to five reuse cycles. On the other hand, the removal capacity depends on the amount of polysiloxane chain in the ceramic, as well as the functional group, exhibiting the following behavior: DMS-N < DMS-CH₃ < PDS. This study demonstrates that hydrophobicity is a key property for enhancing the removal capacity of oily substances. Moreover, the control of intermolecular interactions further strengthens this effect, as evidenced in the PS/SiO₂–PDS system. Full article

Background: Periplaneta americana grease (PAG), a lipid-rich fraction with documented wound-repair properties, remains challenging. This study aimed to develop a stable and patient-friendly film-forming agent (PAP) from PAG for topical wound management. Methods: The chemical profile of PAG was characterized with GC-MS. The formulation was optimized via single-factor and orthogonal experimental design. Comprehensive physicochemical characterization was performed. A vehicle control (film without PAG) was used to isolate PAG’s bioactive effects. In vitro, antioxidant (DPPH/ABTS assays) and antibacterial activity were evaluated. In vivo efficacy was assessed using a murine full-thickness wound model (mice, 150 µL applied 3 times daily for 10 days), with bFGF and Kangfuxin solution as positive controls. Histological analysis was conducted on healed tissue. Results: GC-MS revealed PAG’s complex composition, rich in sterols, terpenoids, and heterocyclic compounds. The optimized PAP formed a uniform, flexible film with suitable mechanical strength and shear-thinning rheology. PAP showed significant antioxidant activity and selective antibacterial activity against Staphylococcus aureus. In the wound model, PAP treatment significantly accelerated wound closure, achieving a 98.2% healing rate by day 10, comparable to positive controls and significantly superior to the vehicle control. Histology demonstrated enhanced re-epithelialization, reduced inflammation, and improved collagen organization. Conclusions: PAP was successfully formulated into a multifunctional film-forming agent that addresses key barriers to healing—infection, oxidative stress, and tissue regeneration. The results demonstrate its potential as an innovative therapeutic strategy for wound care. Full article

This study investigates the impact of multilayer structures and drying strategies on the barrier properties of high-speed starch/bentonite-coated paperboard. The study examines the impact of drying at a high machine speed of 400 m min⁻¹, addressing a key knowledge gap. The hypotheses were that thin multilayer coatings reduce oxygen permeability more effectively than thick single or double coatings and that gentle infrared (IR) drying would be required to achieve this effect. The experiments comprised up to six consecutive coating applications, each providing a dry coat weight between 0.5 and 1.5 g m⁻². The IR dryer power ranged from 207 kW to 829 kW, and different IR frame positions were tested. The results indicated that thin multilayer coatings resulted in fewer pinholes, lower oxygen transmission rates, and improved grease resistance compared with one or two thick layers. However, the effectiveness of the multilayer-coated paperboard was influenced by the employed drying strategy. Specifically, gentle IR drying reduced pinholes, lowered oxygen transmission rates and enhanced grease resistance. Full article

Lubrication performance dominates the rating life of grease-lubricated pitch bearings. Conventionally, the life modification factor is determined using base oil viscosity, whose validity is rarely verified. This work presents an effective viscosity-based method for life evaluation of wind turbine pitch bearings. The effective viscosity of grease is measured under actual operating conditions, and a comparative study is conducted against the conventional base oil viscosity method. The rationality of the proposed approach is validated by bearing life tests. Results indicate that the life modification factor calculated from effective viscosity agrees significantly better with test data. Adopting effective viscosity can substantially improve the accuracy of bearing life prediction. The proposed method provides a reliable and practical way to assess the lubrication performance and fatigue life of pitch bearings. Full article

The improper management of fats, oils, and grease (FOG) from food services is a major cause of sewer blockages and environmental damage. This study examines FOG management in the restaurant sector of the Guadalajara Metropolitan Area, Mexico, from three complementary perspectives: the performance of the authorized formal collection system, management practices in food establishments, and the physicochemical characteristics of grease trap residues. These perspectives were addressed using official administrative records and reports from environmental authorities, structured surveys applied to kitchen staff, and laboratory analyses of grease trap samples collected in restaurants. The results reveal important institutional and structural constraints affecting FOG management. Only a limited number of authorized collectors operate actively, serving a small fraction of potential generators, while most food service establishments are micro- or small-sized businesses with limited technical and financial capacity to comply with regulations. A large portion of the sector consists of small, low-cost food service establishments with intensive oil use (e.g., street food vendors, sandwich shops, and set-menu restaurants), which contribute to widespread oil reuse and inadequate disposal practices. Laboratory analyses showed a high free fatty acids (FFAs) content and compositional profiles consistent with repeated oil use, with negative implications for sewer systems and waste management. Overall, the findings highlight the need for stronger regulatory enforcement, collection schemes tailored to micro-scale generators, and awareness campaigns while also indicating opportunities for FOG valorization within circular economy approaches, particularly through energy recovery pathways. Full article

Biodiesel is a promising, renewable, and environmentally friendly alternative fuel. Numerous studies have focused on improving the biodiesel production process from various feedstocks using different activation methods and catalysts. However, the reaction times typically range from tens of minutes to hours. This study presents, for one of the first systematic studies exploring time, the potential of using millimeter-wave electromagnetic radiation generated by a gyrotron as an activation method for biodiesel production reactions. Esterification was carried out using free fatty acids and fatty waste, specifically brown grease (BG), in the presence of the Lewis acid catalyst AlCl₃. Complete conversion of oleic acid was achieved after only 0.4 s of exposure to millimeter waves. When BG was used as the feedstock, a biodiesel yield of 73–76% was obtained within only 3.0 s. Gyrotron-based electromagnetic activation was benchmarked against conventional thermal and sonication-assisted methods, demonstrating high effectiveness. This study presents an efficient and novel process that reduces reaction times while utilizing fatty waste as a feedstock, aligning with the principles of green chemistry, the circular economy, and sustainable development. Full article

With the advancement of wind power technology towards larger-capacity and higher-power turbines, their main shaft bearings face significant lubrication challenges under extreme temperatures. In this study, seven modified greases were prepared by adding 0.5 wt.% of tungsten disulfide (WS₂), zinc sulfide (ZnS), and sulfurized isobutylene (T321). The concentration of all additives is given in weight percent (wt.%). Using a combined approach of friction and wear testing along with rheological analysis, this study systematically evaluated the tribological performance of the greases at high temperature (80 °C)—with the friction coefficient and wear scar diameter as key parameters—and their rheological properties across a wide temperature range (−20 °C to 80 °C), focusing primarily on shear stress and viscosity. All critical input parameters, including temperature, load, and shear rate, were precisely controlled and monitored using calibrated instruments. Results indicate that the WS₂ and T321 compounding system demonstrated optimal performance, achieving a low average coefficient of friction of 0.024 and an average wear scar diameter of only 0.367 mm. At the same time, the WS₂/T321 composite formulation exhibits excellent shear stability at high temperatures and good flow properties at low temperatures, demonstrating optimal viscosity–temperature characteristics. This study develops a promising grease formulation through multidimensional performance evaluation, offering key experimental support for designing high-performance wind turbine spindle bearing greases under high-temperature conditions. Full article

This study presents a zooarchaeological and taphonomic analysis of the previously unstudied component of the Mousterian faunal assemblage from Unit A9 at Grotta di Fumane (northeastern Italy), offering refined insights into Neanderthal subsistence behaviour during Marine Isotope Stage 3. Building on the previously published analysis of the principal portion of the assemblage, the new data reaffirm a subsistence strategy focused on selective transport and intensive on-site processing of high-utility carcass components. The ungulate assemblage—dominated by Cervus elaphus and Capreolus capreolus, with additional contributions from Rupicapra rupicapra and Capra ibex—is characterised by the dominance of hindlimb elements, moderate cranial representation, and a pronounced scarcity of axial remains. These patterns indicate that carcass reduction commenced at kill sites, where low-yield trunk segments were removed, while high-nutritional-value limb portions were preferentially transported to the cave for secondary processing. Taphonomic indicators, including abundant cut marks, percussion notches, and extensive bone fragmentation, demonstrate systematic defleshing, marrow extraction, and possible grease rendering within the cave, activities that were spatially associated with combustion features. Occasional cranial transport suggests targeted acquisition of high-fat tissues such as brains and tongue, behaviour consistent with cold-climate optimisation strategies documented in both ethnographic and experimental contexts. Collectively, the evidence indicates that Unit A9 served as a residential locus embedded within a logistically organised mobility system, where carcass processing, resource exploitation, and lithic activities were closely integrated. These findings reinforce the broader picture of late Neanderthals as adaptable and behaviourally sophisticated foragers capable of strategic planning and efficient exploitation of ungulate prey within the dynamic environments of northern Italy. Full article