Search Results (2,997)

This study investigates the molecular interactions and interfacial behaviors of a carboxylate-sulfonate gemini surfactant (CSGS) with four heavy-oil components (SARA: saturates, aromatics, resins, and asphaltenes) using molecular dynamics (MD) simulations. To provide a comprehensive analysis, two distinct systems were constructed: a homogeneous bulk oil phase (System 1) and a solid–liquid interfacial system containing a calcite (CaCO₃) substrate (System 2). In System 1, results showed that CSGS remained well dispersed in the bulk heavy-oil phase and promoted a more uniform distribution of the SARA components. The differences in mobility among the components were mainly determined by molecular structure, resulting in a consistent diffusion trend in the CSGS-containing bulk system. In contrast, the introduction of a calcite substrate (System 2) shifted the distribution from a largely disordered bulk-like state to a confined interfacial organization, with clear layering and enrichment near the mineral surface. Compared with the CaCO₃-free system, molecular migration was noticeably restricted, indicating that the carbonate layer imposed additional constraints on mass transport. At the same time, CSGS preferentially accumulated in the SARA components–CaCO₃ region, consistent with competitive adsorption at the carbonate interface, and further reorganized the local interfacial structure. Full article

A twin-screw multiphase pump is essential equipment for the transfer of gas-liquid multiphase mixtures in oil and gas operations. This work addresses rotor deformation in real applications by correcting the rotor profile using the arc transition approach, eliminating teeth tips, mitigating local stress concentration, and reducing the danger of rotor deformation. Simultaneously, in conjunction with the oil and gas mixed transportation requirements of the Changqing Oilfield, the MPC208-67 twin-screw mixed transportation pump was engineered, and the essential structural specifications were established. This paper employs the Mixture multiphase flow model and the SST k-ω turbulence model to simulate the internal flow field of the pump in Changqing Oilfield, aiming to examine the impact of high-gas-content conditions on the pump’s performance and ensure it aligns with design specifications. The modeling findings indicate that the pressure in the pump progressively rises along the axial direction and remains constant within the chamber. As the void fraction of the medium increases, the pressure differential between the inlet and exit of the rotor fluid domain progressively diminishes, resulting in high-velocity fluid emerging in the interstice between driving and driven rotors. The simultaneous increase in rotational speed elevates the overall fluid velocity while diminishing the pressure value. Under rated conditions, the output pressure and flow rate of the planned multiphase pump achieve 1.8 MPa and 300 m³/h, respectively, thereby fully satisfying the design specifications. This work employs the response surface approach to optimize multi-objective performance parameters, including leakage and pressurization capacity, to enhance the pump’s operational performance under high gas content situations. The optimization results indicate a 17.87% reduction in pump leakage, an 8.86% rise in pressurization capacity, and a substantial enhancement in pump performance. Full article

Wear, a critical factor governing the performance and durability of mechanical systems, is typically characterized using point-contact and line-contact test configurations. However, it remains unclear whether the wear trends observed in one test configuration would be observed in the other configuration under the same nominal conditions. In this study, ball-on-disk (ASTM G99) and block-on-ring (ASTM G77) tests were conducted under an identical maximum Hertzian contact stress and sliding speed, using the same material pair and lubricating oil, to clarify which contact configuration exhibits more wear and why. The results show that, under the same Hertzian contact stress, the line-contact configuration exhibits a specific wear rate two orders of magnitude higher than the point-contact configuration, despite exhibiting a lower and more stable coefficient of friction. The disk wear is negligible and the ball shows only mild material loss, whereas the line-contact system displays wear rates several orders of magnitude higher, with the rotating ring contributing the dominant share of the total wear. White-light interferometry and scanning electron microscopy observations reveal directional, groove-dominated surface morphologies on the ball and disk, while wear on the block is confined to edge-localized regions and the worn ring surface has smooth, polished morphology. Energy-dispersive X-ray spectroscopy confirms that a Zn- and P-rich tribofilm forms exclusively on the ring surface. Finite element analysis shows stress amplification at the finite line-contact edges, explaining the observed wear severity. These results demonstrate that matching Hertzian contact stress alone is insufficient to ensure comparable wear behavior between point and line contacts. Full article

The reliance on synthetic repellents such as N,N-diethyl-meta-toluamide (DEET) has raised health and environmental concerns, prompting the search for safer, plant-based alternatives. Catnip (Nepeta cataria L.), a rich source of iridoid monoterpenes, particularly nepetalactones, known for strong insect-repellent activity. However, their efficient extraction and molecular mechanisms in insect inhibition remains challenging. This study examined the chemical composition, protein–ligand interactions, and safety profiles of nepetalactones in comparison with DEET, with particular focus on mosquito odorant-binding proteins (OBPs) from Anopheles gambiae (AgamOBP), Culex quinquefasciatus (CquiOBP), and Aedes aegypti (AaegOBP). GC–MS/MS analysis identified nepetalactone isomers as the predominant constituents in catnip extracts obtained via steam distillation and olive oil extraction from dried leaves. Molecular docking results indicated that cis,cis-, cis,trans-, and nepetalactone isomers exhibited higher binding affinities toward the target OBPs than DEET. Furthermore, molecular dynamics simulations confirmed that all nepetalactone–OBP complexes exhibited stable conformations characterized by low average RMSD values and persistent hydrogen bond formation. Notably, cis,trans-NL–AaegOBP, NL–AaegOBP, and cis,cis-NL–AgamOBP complexes displayed lower binding free energies (ΔG_MM-PBSA) compared to DEET. These findings suggest that nepetalactones stabilize OBP–ligand interactions while inducing subtle conformational flexibility, potentially disrupting mosquito odorant recognition in a manner distinct from DEET. ADMET predictions indicated that nepetalactones exhibit favorable absorption, distribution, and safety profiles with reduced predicted toxicity compared to DEET. Collectively, these results establish nepetalactones as promising candidates for the development of effective, safe, and sustainable plant-based repellents. Full article

This study investigates how Vision Language Models (VLMs) can be used and methodically configured to extract Environmental, Social, and Governance (ESG) metrics from corporate sustainability reports, addressing the limitations of existing text-only and manual ESG data-extraction approaches. Using the Design Science Research Methodology, we developed an extraction artifact comprising a curated page-level dataset containing greenhouse gas (GHG) emission-reduction targets, an automated evaluation pipeline, model and text-preprocessing comparisons, and iterative prompt and few-shot refinement. Pages from oil and gas sustainability reports were processed directly by VLMs to preserve visual–textual structure, enabling a controlled comparison of text, image, and combined input modalities, with extraction quality assessed at page and attribute level using F1-scores. Among tested models, Mistral Small 3.2 demonstrated the most stable performance and was used to evaluate image, text, and combined modalities. Combined text + image modality performed best (F1 = 0.82), particularly on complex page layouts. The findings demonstrate how to effectively integrate visual and textual cues for ESG metric extraction with VLMs, though challenges remain for visually dense layouts and avoiding inference-based hallucinations. Full article

RCCI is a promising combustion strategy that can improve the controllability of combustion phasing. This study evaluates fusel oil (an inexpensive industrial by-product) as a low-reactivity supplementary fuel in an RCCI diesel engine. Fusel oil was injected into the intake air at 4, 6, 10, 12, and 16 g/min (DF4-DF16), and experiments were conducted on a four-cylinder, four-stroke diesel engine at 1750 rpm under 40, 60, 80, and 100 Nm. In-cylinder temperature/pressure-based combustion behaviour, air excess ratio (λ), NO and smoke emissions were assessed. The influence of fusel oil on combustion was strongest at low load. At 40 Nm, the highest fusel-oil energy share increased peak cylinder pressure by 14% and peak in-cylinder temperature by 4% compared to diesel fuel tests, while at 100 Nm the corresponding increases were 4% and less than 1%. NO increased at 40 Nm, with a maximum rise of 17.9% at the highest fusel-oil energy share, but decreased at medium and high loads, falling by 7.13 to 13.54% between 60 and 100 Nm. Smoke increased consistently with fusel oil, reaching about 42% at 40 Nm and remaining below 22% at 100 Nm. A techno-economic assessment showed that although capital costs increased slightly, the low price of fusel oil decreased operating costs by up to 33% and reduced life-cycle costs by up to 42%. Overall, fusel oil-assisted RCCI operation can provide notable cost benefits and conditional NO reductions, though with a smoke penalty that should be considered in application and after-treatment strategies. Full article

Coconut residue (CR) is a major by-product generated during the wet processing of virgin coconut oil (VCO). Despite its potential as a raw material for value-added products such as dietary fiber, it remains underutilized due to its perishable nature, highlighting the need for appropriate pretreatment to improve safety and quality prior to valorization. This study evaluated the effects of thermal pretreatments, namely pan-roasting at 65–70 °C, hot-air drying at 50 °C and 60 °C, and their combinations, on the microbiological and physicochemical properties of CR. Microbiological quality was assessed through aerobic plate count, yeast and mold count, and total coliform analysis, while physicochemical properties were evaluated using pH, titratable acidity (TA), and instrumental color measurements. Results showed that CR subjected to pan-roasting, either alone or followed by drying at 60 °C, maintained acceptable microbial counts and generally exhibited lower TA and higher pH compared to other treatments, suggesting improved stability and reduced acidity development. However, pan-roasting caused color changes as reflected by a significant reduction in lightness (L*) values relative to the control. Overall, pan-roasting could serve as a promising thermal pretreatment step to enhance microbiological safety and preserve the physicochemical quality of CR. While these results indicate its potential for preparing CR for dietary fiber valorization, confirmation through analysis of fiber content, techno-functional properties, and validation using CR from commercial VCO processing facilities is still required. Full article

Functional coatings for food packaging offer innovative approaches to extend shelf life, preserve quality and introduce active properties such as antimicrobial or antioxidant effects. These coatings include natural bio-based films (e.g., polysaccharide or protein-based) and synthetic polymers enhanced with additives or nanomaterials. Despite their advantages (e.g., improved barrier properties, spoilage inhibition, or intelligent sensing) they also pose safety concerns. Migration of chemical constituents and additives into food can lead to toxicological risks, such as cytotoxicity or endocrine disruption. Non-intentionally added substances (NIASs) and nano-sized components further complicate safety assessments. This review outlines the main types of functional coatings, their active mechanisms, and associated safety issues. Particular focus is placed on migration phenomena, chemical interactions and health risks from common migrants including plasticizers, monomers, nanoparticles and essential oils. The EU Packaging and Packaging Waste Regulation (Regulation (EU) 2025/40), adopted in December 2024 and published in the Official Journal in January 2025, introduces comprehensive sustainability and substance-restriction requirements, including strict criteria for food packaging materials that will apply from 12 August 2026. Emerging challenges include the assessment of bio-based and recycled coatings and the toxicology of nanomaterials. Balancing functionality with safety remains crucial for next-generation, sustainable and health-compliant food packaging. Full article

The aging and failure of transformer bushing seals under multi-factor effects are significant causes of oil leakage incidents. However, their failure mechanisms under combined environmental stressors remain inadequately understood. This study presents a comprehensive investigation into the aging behavior and failure mechanisms of nitrile rubber (NBR) and fluoroelastomer (FKM) sealing materials subjected to single and multi-factor aging conditions, including thermo-oxidative, hygrothermal, hygrothermal–compression, and hygrothermal–compression–salt environments. NBR undergoes severe degradation under multi-factors, dominated by additive loss and molecular chain crosslinking. At high temperatures, large-scale molecular chain scission occurs, along with increased compression set, microscopic morphological damage, and filler precipitation. In contrast, FKM exhibits excellent stability thanks to its C-F main chain. Stress synergy significantly accelerates the failure of both materials. These findings highlight the need for multivariate analysis to support reliable condition assessment and lifetime prediction and to inform sealing material selection and proactive grid maintenance. Full article

Songliao Basin hosts abundant shale oil and gas resources, yet the phase behavior of the fluids is still unclear since the confinement effect of the shale reservoir alters the adsorption effect on the pore walls. In this study, molecular dynamics (MD) simulations were employed to clarify this issue. A binary mixture was built to represent Gulong shale oil and the phase state properties under the confinement effect were evaluated. In addition, a series of pure alkane models were constructed to analyze the influence of hydrocarbon type, temperature, and mineral composition on phase behavior. The simulation results showed that the typical Gulong shale fluid remains liquid state in the nanopores. Owing to the confinement effect, both viscosity and density under nano space decrease sharply compared to those at bulk space. Therefore, field development should somewhat rely on high-pressure stimulation to create flow paths, followed by CO₂ huff-and-puff technology to maintain production pressure. In addition, fluid composition, temperature, and mineral type are the primary factors governing the magnitude of the confinement effect. Full article

The genus Thymus L. is characterized by high taxonomic complexity and pronounced phytochemical polymorphism, which underlie its economic and medicinal importance. While a limited number of species (Thymus vulgaris, Thymus pulegioides, Thymus × citriodorus) are traditionally cultivated, the cultivation potential of many Balkan taxa remains poorly explored. The present study aimed to evaluate the field cultivation performance, essential oil yield, and chemotype differentiation of three traditional and three lesser-studied Thymus species (Thymus zygioides Griseb., Thymus longedentatus (Degen & Urum.) Ronniger, and Thymus pannonicus All.). Plants were established through vegetative propagation and cultivated under field conditions, followed by essential oil isolation and GC–MS analysis. The newly introduced species exhibited higher essential oil yields, reaching 2.30% in T. longedentatus, 1.48% in T. pannonicus, and 0.94% in T. zygioides, compared to 0.24–0.60% in traditionally cultivated species. Clear and species-specific chemotypes were identified: a citral (neral/geranial) chemotype in T. longedentatus, a thymol chemotype in T. zygioides, and a sesquiterpene-dominated profile in T. pannonicus. In contrast, traditionally cultivated species displayed overlapping and less differentiated chemical profiles. All species were propagated vegetatively and cultivated in an open-field experimental plantation under temperate continental climatic conditions, following environmentally responsible horticultural practices. Vegetative propagation ensured genetic uniformity and supported consistent chemotype expression of the planting material under the applied cultivation conditions. These results demonstrate that species-based selection represents a robust alternative to conventional thyme cultivation, enabling higher essential oil productivity, clearer chemotypic differentiation, and improved standardization for horticultural and medicinal plant production, while supporting the sustainable use of native Bulgarian biodiversity. Full article

Heavy-duty vehicles dominate global freight movement and primarily rely on fossil-derived diesel fuel. However, fluctuations in crude oil prices and evolving emissions regulations have prompted interest in alternative powertrains to enhance fleet energy resiliency. This study paired real-world operational data from a large commercial fleet with high-fidelity vehicle models to evaluate the potential for replacing diesel internal combustion engine (ICE) trucks with alternative powertrain architectures. The baseline vehicle for this analysis is a diesel-powered ICE truck. Alternatives include ICE trucks fueled by bio- and renewable diesel, compressed natural gas (CNG) or hydrogen (H₂), as well as plug-in hybrid (PHEV), fuel cell electric (FCEV), and battery electric vehicles (BEV). While most alternative powertrains resulted in some payload capacity loss, the overall fleetwide impact was negligible due to underutilized payload capacity for the specific fleet considered in this study. For sleeper cab trucks, CNG-powered trucks achieved the highest replacement potential, covering 85% of the fleet. In contrast, H₂ and BEV architectures could replace fewer than 10% and 1% of trucks, respectively. Day cab trucks, with shorter daily routes, showed higher replacement potential: 98% for CNG, 78% for H₂, and 34% for BEVs. However, achieving full fleet replacement would still require significant operational changes such as route reassignment and enroute refueling, along with considerable improvements to onboard energy storage capacity. Additionally, the higher total cost of ownership (TCO) for alternative powertrains remains a key challenge. This study also evaluated lifecycle impacts across various fuel sources, both fossil and bio-derived. Bio-derived synthetic diesel fuels emerged as a practical option for diesel displacement without disrupting operations. Conversely, H₂ and electrified powertrains provide limited lifecycle impacts under the current energy scenario. This analysis highlights the complexity of replacing diesel ICE trucks with admissible alternatives while balancing fleet resiliency, operational demands, and emissions goals. These results reflect a US-based fleet’s duty cycles, payloads, GVWR allowances, and an assumption of depot-only refueling/recharging. Applicability to other fleets and regions may differ based on differing routing practices or technical features such as battery swapping. Full article

Population growth in Grand Lomé is increasing households’ dependence on food markets in a context of rising prices. This study analyzes the price instability of staple foods, its determinants, and its effects on the coping strategies of urban households. It is based on a mixed-methods approach combining quantitative surveys of 245 traders, 210 buyers, and 310 households, as well as interviews with institutional stakeholders. The results reveal price increases of up to 79% and non-stationarity in the price series for maize, local rice, cowpea, gari, fish, and oil, while those for yam and tomato remain stable. Logit modeling identifies constraints related to insufficient access to storage as the most significant factor, followed by transport costs, taxation, access to credit, access to information, and product quality. Faced with this instability, more than 35% of urban households spend a major portion of their income on food and increasingly rely on street food, raising nutritional and health concerns. The findings advocate for urban policies that combine reduced logistical and fiscal costs, improved access to credit and market information, and risk financing mechanisms to sustainably strengthen urban food security, particularly in Grand Lomé, Togo. Full article

Essential oils from species of the genus Varronia (Boraginaceae) are recognized for their chemical diversity and biological potential; however, phytochemical information on Varronia crenata Ruiz & Pav. remains scarce, despite its wide distribution in the Andean region. The aim of this study was to provide the first chemical and enantioselective characterization of the essential oil obtained from the leaves of V. crenata growing in Ecuador. Qualitative and quantitative analyses were carried out by GC–MS and GC–FID, respectively, using two columns with stationary phases of contrasting polarity. Compounds were identified by matching linear retention indices and mass spectra to literature references and quantified by external calibration using relative response factors (RRFs) calculated for each compound based on its combustion enthalpy. The most abundant constituents (≥3.0% on average between the two columns) of the essential oil of V. crenata, both in the nonpolar and polar stationary phases, were germacrene D (18.4%), (E)-β-caryophyllene (13.3%), α-copaene (10.4%), tricyclene (9.3%), δ-cadinene (8.9%), and α-pinene (8.3%). The volatile fraction was dominated by sesquiterpenes (60.2%) and monoterpenes (22.1%), while other chemical families were present in minor proportions. The enantioselective analysis was performed on two different columns, coated with stationary phases based on β-cyclodextrins: 2,3-diacetyl-6-tert-butyl-dimethylsilyl-β-cyclodextrin and 2,3-diethyl-6-tert-butyl-dimethylsilyl-β-cyclodextrin. Nine chiral compounds were analyzed; among them, (1R,5R)-(+)-α-pinene, (1R,5R)-(+)-sabinene, and (S)-(+)-β-phellandrene were detected as enantiomerically pure, while the other metabolites presented scalemic mixtures. Overall, the high content of bioactive sesquiterpenes and the observed stereochemical complexity highlight the potential pharmaceutical and agricultural relevance of V. crenata essential oil, while also providing novel chemotaxonomic information for the genus. Full article

Amine-functionalized solid adsorbents are widely recognized as promising candidates for direct air capture of CO₂; however, their practical deployment remains constrained by humidity-dependent adsorption behavior and poor packed-bed operability arising from irregular particle morphology and fines generation. Rather than focusing solely on maximizing intrinsic adsorption capacity, this study addresses these process-level limitations through an integrated design strategy combining particle morphology control with surface chemistry optimization. Uniform spherical magnesium silicate particles with a mean diameter of approximately 15 μm were synthesized via a water-in-oil emulsion route to suppress fines formation and reduce hydrodynamic resistance. Controlled acid pretreatment was subsequently applied to adjust surface hydroxyl accessibility and enable efficient amine grafting without altering bulk composition. The optimized spherical magnesium silicate amine adsorbents exhibited pronounced humidity-enhanced carbon dioxide capture, achieving capacities of 1.7 to 1.8 millimoles/g at 50% relative humidity, representing an approximately fourfold increase compared with dry conditions. This enhancement is attributed to a humidity-induced mechanistic transition from carbamate formation under dry conditions to water-assisted bicarbonate formation under humid conditions. Complete regeneration was achieved at 100 °C, with stable adsorption desorption behavior maintained over ten consecutive cycles, demonstrating short-term reversibility. These findings highlight morphology controlled scalability. Future work should prioritize durability beyond 100 cycles, mechanical robustness, and techno-economic viability at scale. Full article