Search Results (539)

Fruity natural flavors are widely used in food, cosmetics, and tobacco products, and their flavor profiles directly affect the sensory quality of the final products. However, the volatile organic compound systems in these flavors are highly complex, and severe co-elution among volatile components makes effective component resolution a persistent analytical challenge. In this study, comprehensive two-dimensional gas chromatography–olfactometry–time-of-flight mass spectrometry (GC×GC-O-TOF-MS) was employed to separate and identify volatile odor compounds in three natural fruit flavor extracts: plum, jujube, and grape. A total of 113, 103, and 85 volatile odor compounds were identified from the plum, jujube, and grape extracts, respectively. By progressively adjusting the split ratio, aroma extract dilution analysis was performed, leading to the screening of 14, 11, and 32 aroma-active compounds from the three extracts, respectively. Compounds with high flavor dilution factors were subjected to quantitative analysis, and their odor activity values were calculated. Subsequently, omission and recombination experiments were conducted to confirm the key aroma-active compounds in each extract. The results showed that octanal was a key aroma compound shared by the plum and jujube extracts, while ethyl cinnamate was common to both the plum and grape extracts. Through a molecular sensory science approach and utilizing GC×GC-O-TOF-MS chromatographic separation technology, this study provides a reliable analytical platform for aroma characterization in complex samples. It also establishes a critical theoretical and data foundation for precisely identifying key aroma-active components and implementing targeted aroma modulation to enhance the natural flavor quality of fruits. Full article

Membrane separation is an efficient approach for volatile organic compound (VOC) recovery from industrial off-gases due to its low energy consumption, compact design, and operational simplicity. Membrane-based VOC recovery critically depends on the membrane material, which must exhibit high VOC permeability and selectivity under mixed-gas conditions. In this study, novel highly selective membranes for VOC removal based on polydecylmethylsiloxane (PAMS-10) were synthesized using both polydimethylsiloxane and various α,ω-dienes as cross-linkers: 1,7-octadiene (OD), 1,9-decadiene (DD), and 1,11-dodecadiene (DdD). The influence of cross-linker concentration and length on mechanical, structural, sorption, and transport properties was examined extensively. The combination of three independent experimental methods (time-lag, vapor permeation, and in situ spectroscopic ellipsometry) revealed that increasing α,ω-diene concentration and decreasing its length led to a reduction in the diffusivity and permeability of permanent gases, gaseous hydrocarbons, and VOC vapors. For VOC/N₂ separation, the slightly cross-linked OD-1 membrane and the DdD-5 membrane, cross-linked with long 1,11-dodecadiene, demonstrated outstanding mixed-gas selectivities of 950/921/314/840 and 940/1084/233/1106 for toluene/n-octane/i-octane/n-butyl acetate, respectively. Notably, the DD-5 membrane, cross-linked with 1,9-decadiene, matching the length of the PAMS-10 side chain substituent, exhibited the best mechanical properties and mixed-gas selectivity comparable to the ideal selectivity, a unique behavior attributed to optimal supramolecular organization. Full article

This exploratory study assessed the vehicle- and route-dependent response of five multipoint injection passenger vehicles to two commercial fuel additives marketed as octane-related gasoline additives under real-world high-altitude driving conditions in Quito, Ecuador. The tests were conducted on one urban route and one rural/peripheral route using base gasoline with a nominal octane index of RON 85, RON 85 gasoline with Additive A, and RON 85 gasoline with Additive B. Fuel economy and CO₂-related indicators were obtained through the OBD-II port using the Torque Pro application; therefore, the reported values were interpreted as electronic control unit-based estimates rather than direct gravimetric fuel consumption or laboratory emissions measurements. The revised analysis used OBD-derived trip-average fuel economy as the primary response variable. The mixed-effects model showed a significant effect of route on fuel economy (p < 0.001) and a significant fuel condition × route interaction (p = 0.0089), while the main effect of fuel condition was not statistically significant (p = 0.0699). Additive B increased the mean OBD-derived trip-average fuel economy on the urban route from 11.56 to 12.60 km·L⁻¹, but reduced it on the rural route from 13.46 to 12.65 km·L⁻¹. At the vehicle level, the previously extreme Vehicle 3 response was revised to a more plausible increase from 11.03 to 13.64 km·L⁻¹ (+23.68%) when trip-average fuel economy was used. Since the actual RON/MON values and physicochemical properties of the final fuel blends were not experimentally measured, the observed responses cannot be attributed exclusively to octane number enhancement. Overall, the findings indicate that commercial additive performance was vehicle- and route-dependent rather than universally beneficial. This field-based assessment supports evidence-informed decision-making for sustainable mobility and aligns with SDG 16 and SDG 17 through transparent technical evaluation and academic collaboration. Full article

The warm and smooth taste, combined with the pleasant sweet aroma, are unique quality characteristics of Pingyang Huangtang (PYHT) tea. However, the potential to refine the quality through agricultural practices remains poorly explored. In this study, a one-year field experiment was conducted in the core production region of PYHT tea to assess the impacts of organic fertilizer substitution on tea quality. The experiment consisted of three fertilization regimes: T0 (pure chemical fertilizer), T1 (chemical fertilizer with rapeseed cake), and T2 (chemical fertilizer with newly organic fertilizer). Through sensory evaluation, determination of major biochemical components, and GC-MS analysis of aromatic compounds, combined with multivariate statistical methods, results showed that varied fertilization treatments significantly affected the aroma quality of PYHT tea, as indicated by T2 scoring the highest, surpassing the T0 and T1 scores, whereas no significant differences were observed in appearance, taste, liquor color, infused tea, or total score. Compared with chemical fertilization, organic fertilizer substitutes significantly reduced the total content of ammonia acids, a change primarily attributed to the decrease in the Thea, Arg, and Val levels, while the tea polyphenols and caffeine had no significant differences among treatments. GC-MS and multivariate analysis identified five key volatiles as octan-1-ol, linalool, geraniol, benzeneacetaldehyde, and δ-cadinene that differentiated the tea samples’ aroma profile. The distinct abundance patterns of these compounds are likely responsible for a fresher and more pronounced floral style of T2 tea, compared to the slightly less fresh floral notes of T0 tea and the stuffy floral expression of T1 tea. In summary, the research findings offer actionable guidelines for fertilizer application to PYHT tea production, improving aroma quality and increasing its overall market value. Full article

Two metallacyclic tetranuclear Fe(III) complexes, [{Fe₂(μ-O)(μ-RCOO)₂(tpon)}₂](BPh₄)₄ [R = Me (1), Ph (2)], where the flexible ditopic ligand tpon (N,N,N′,N′-tetrakis(2-pyridylmethyl)octane-1,8-diamine) links two μ-oxo-bis(μ-carboxylato) triple-bridged dinuclear units, have been prepared. Single-crystal X-ray diffraction establishes that both complexes adopt a 26-membered macrocyclic framework featuring an internal cavity capable of guest inclusion. Notably, incorporation of a monoatomic μ-oxo bridge enforces an outward orientation of the ligand alkyl chains, thereby suppressing the “zipper effect” observed in the previously reported Mn(II) analogue and facilitating the encapsulation of an acetone molecule. UV–vis absorption and diffuse-reflectance spectra confirm that the tetranuclear scaffold remains intact in both the solid state and in solution. These results demonstrate that modulating local coordination directionality via μ-oxo bridging is an effective strategy for controlling the global conformation and host–guest properties of large metallasupramolecular architectures. Full article

Luminescent organic–inorganic Cu(I) halide hybrid molecular crystals exhibit remarkable structural diversity and photophysical properties, but their application in aqueous environments is often limited by insufficient stability. Herein, we report portable and reusable photoluminescent sensors based on Cu(I)–I triethylenediamine derivatives [Cu₄I₆(pr-ted)₂] and [Cu₃I₅(bz-ted)₂] (pr-ted = 1-propyl-1,4-diazabicyclo[2.2.2]octan-1-ium; bz-ted = 1-benzyl-1,4-diazabicyclo[2.2.2]octan-1-ium). Their submicrometric particles exhibit intense UV-excited emissions and high photoluminescence quantum yields but limited water stability. To address this limitation, ultrasound sonication was employed to control particle size and produce stable suspensions that can be incorporated into polymeric matrices via 3D printing with photocurable resins or polylactic acid (PLA) films by drop-casting, yielding mechanically robust composites that retain their structural and optical properties. The devices used act as selective turn-off luminescent sensors for Fe³⁺ in aqueous media, with nanomolar detection limits (1.33–1.58 nM) below regulatory thresholds for drinking water. Moreover, [Cu₃I₅(bz-ted)₂] enables tetracycline detection in river water with a limit of detection of 0.038 nM. Mechanistic studies indicate that reversible photoinduced electron transfer is the primary quenching pathway, while composites maintain sensing performance over multiple reuse cycles. Full article

Diesel engines have evolved significantly over the last century while maintaining core qualities such as reliability, durability, and fuel economy. Currently, the viability of their continued use is under discussion, mainly due to the environmental impact of polluting emissions from conventional fossil fuels. An advantage of these engines is their high fuel flexibility, which includes the capability to operate with pure vegetable oils. Following the established limitations of large-scale conventional biodiesel use, this perspective explores the implementation of straight vegetable oils (SVOs) blended with low-viscosity, low-octane (LVLC) oxygenated solvents to address climate targets such as the “Fit for 55” agenda. The discussion examines the potential of these advanced biofuels to contribute to the 2050 carbon neutrality goals while addressing the technical and economic requirements of the transport sector. Full article

The insufficient octane ratings of commercial fuels limit the efficiency of spark-ignition (SI) engines and worsens emissions due to knock. One alternative approach to mitigate this phenomenon is the Octane-on-Demand (OOD) concept, which adjusts fuel properties onboard the vehicle. Although implementing this advanced technology can contribute to greenhouse-gas (GHG) emission reductions, few studies have examined its impact on combustion characteristics. Accordingly, the objective of this study was to conduct a comprehensive investigation combining fuel characterization and engine testing to evaluate the effectiveness of the OOD strategy in directly suppressing knock in an SI engine, an aspect not previously reported in the literature. The present study was divided into two parts. In the fuel study, optimal conditions for obtaining a candidate fuel—high-octane fractions (HOF)—from gasoline were determined based on chromatographic (GC–MS) analyses. During engine testing, commercial gasoline and blends containing HOF in several proportions were evaluated in a dual-fuel operation under knocking conditions. The maximum amplitude of pressure oscillations (MAPO) was used as the knock indicator. The results demonstrate that temporary fuel enrichment using only gasoline-derived fractions, without additional octane boosters, can effectively suppress knocking combustion. These findings highlight the influence of the OOD concept on the combustion process and provide guidance for optimizing fueling strategy design under knock-limited operation. The study contributes to the growing body of knowledge regarding OOD applications and underscores the need for comprehensive testing under real-world engine operating conditions. Full article

The unique aroma of ginseng is linked to its recognized mood-enhancing properties. However, the specific aromatic compounds responsible for this effect, as well as the underlying mechanisms across different processed ginseng products, remain unclear. Here, the characteristic pleasant aroma compounds and their potential associations in five preparations—fresh ginseng, white ginseng, Dali ginseng, red ginseng, and black ginseng—were analyzed using flavoromics, bioinformatics, and computational modeling. The aroma evolved from “green” to “roasted-medicinal” notes, with pleasantness peaking in red ginseng, highlighting moderate processing as a key factor. Eight key pleasant aroma compounds were identified (including octanal and β-selinene), which were found to be potentially associated with olfactory- and emotion-related pathways involving IGF1 and OR6A2. Molecular interaction analysis revealed that these compounds may synergistically modulate pleasantness through hydrogen bonding and hydrophobic interactions. Furthermore, aroma harmony proved more decisive than aroma intensity in determining consumer preference, suggesting correlational evidence linking molecular interactions to sensory perception. Dynamic simulations further demonstrated stable interactions between β-selinene, octanal, and IGF1/OR6A2. This research offers new insights into the mood-modulating properties of ginseng aroma and may inform future studies exploring the development of specialized ginseng products for emotional well-being applications. Full article

Data on wildfires (burned area ≥ 100 ha) in South Korea were compiled for 2000–2025 and analyzed together with the national geospatial inventories of hazardous fuel facilities to characterize wildfire-triggered Natech exposure and potential consequence distances. In total, 47 large wildfire events were identified, burning approximately 139,800 ha, with all events occurring during the late winter–spring window (February–May). The spatial overlays of wildfire footprints with facility locations identified 805 gasoline/diesel stations and 227 LPG filling stations located within wildfire-affected districts, corresponding to 14.1% of gas stations and 11.5% of LPG stations in the nationwide facility dataset. Facility exposure was geographically clustered, with the highest concentrations occurring in the eastern and southeastern wildfire hotspots. To quantify potential technological impact extents under wildfire escalation, ALOHA simulations were conducted for a wildfire-induced BLEVE/fireball scenario involving a 10,000 L mobile tank with representative fuels (propane for LPG, n-octane for gasoline, and n-dodecane for diesel). The modeled thermal radiation threat zone radii (10, 5, and 2 kW·m⁻²) were 228/322/502 m for propane, 250/353/550 m for n-octane, and 254/358/559 m for n-dodecane. Together, the event-based wildfire dataset, facility overlay results, and scenario-based impact distances provide an integrated, quantitative basis for assessing wildfire-triggered Natech conditions at the wildland–urban/industrial interface in South Korea. Full article

The aim of this study was to evaluate the bioactive compounds and antioxidant activity of lemon balm (Melissa officinalis L.) grown under two farming systems (conventional vs. organic farming). From the content of photosynthetic pigments, total phenolics, and total flavonoids, as well as individual phenolic acids and flavonoids, the antioxidant potential was evaluated in 95% and 50% ethanol extracts. Moreover, GC-MS analysis of lemon balm essential oils was used to reveal the detailed composition. Forty-three compounds were detected in the essential oil from organic farming lemon balm, representing 99.70% of the total content. Among these, several compounds, such as α-pinene, n-octan-3-ol, bergamal, trans-rose oxide, dihydro-linalool, cis-isocitral, and trans-anethole, were found exclusively in the organic essential oil. In comparison, thirty-six compounds were detected in the essential oil from conventionally grown plants, representing 99.80% of the total content. The organically grown lemon balm demonstrated higher values of phenolics, flavonoids and antioxidant activity in comparison to the conventional ones. The levels of natural pigment were more than twice as high in the conventionally grown samples. Moreover, the 50% ethanol extracts contained 1.5 to 2 times more phenolic compounds with the highest antioxidant potential by the CUPRAC method. A positive linear correlation (r² = 0.98) was found between total phenolics and electron transfer-based antioxidant methods. Therefore, the organic farming led to the production of lemon balm with more secondary metabolites, such as phenolic acids and flavonoids, with higher antioxidant activity. Full article

Modern oil refining is faced with the need to maximize raw material processing in the face of fierce competition and environmental requirements. Therefore, the fluid catalytic cracking (FCC) process, key to the production of high-octane gasoline, requires special attention to automation efficiency. Maintaining optimal reactor temperature is a complex scientific and technical challenge, the solution to which directly impacts the yield of target products and the service life of the catalyst. Existing automatic control systems often fail to cope with process transients, nonlinearities, and time delays, making the search for new control approaches highly relevant. The scientific significance of this study lies in the system analysis and quantitative comparison of the effectiveness of classical control laws (P, PI, PID) applied to a plant with a delay. For the first time, a rigorous comparative analysis of tuning methods—analytical (based on phase margin specifications) and automated (using the PID Tuner tool in MATLAB Simulink R2024b)—is performed for a plant characterized as a second-order system with time delay, formed by the series connection of two first-order lag elements with transport delay. The results contribute to automatic control theory by clearly demonstrating the limitations of the proportional controller and the insufficient speed of the integral controller, as well as confirming the hypothesis that a PID law is necessary to achieve a balance between accuracy and response speed under inertia conditions. The practical significance of the work is confirmed by the development of an optimized automatic temperature control system. Using the PID Tuner tool, we achieved critical industrial performance indicators: zero static error, minimal control time (44 s), and acceptable overshoot (9.6%). The system’s robustness (maintaining stability with changes in plant parameters by 30–40%) and its invariance to the main disturbance (catalyst temperature fluctuations), confirmed during simulation, guarantee the viability of the proposed solution under real-world production conditions. Implementation of such a controller will minimize deviations from the process conditions, leading to increased yield of light petroleum products and an extended service life of the expensive catalyst, providing direct economic benefits. Full article

Large datasets of fuel properties are indispensable for predictive combustion modeling and next-generation fuel design. However, resource-intensive experiments restrict existing databases to 200–500 compounds, capturing an infinitesimal fraction of the C1-20 hydrocarbon space. Furthermore, conventional rule-based and supervised learning extraction methods are constrained by poor scalability, domain-specific nomenclature, and weak contextual inference. To address these limitations, we introduce IgnitionGPT, a large language model fine-tuned on GPT-4.1-mini for the automated, concurrent extraction of three ignition metrics: Research Octane Number, Motor Octane Number, and Cetane Number. The model was trained on a human-annotated JSONL dataset of 304 sources (263 peer-reviewed articles, 41 patents) encompassing 581 diverse compounds. By evaluating IgnitionGPT directly against its zero-shot foundation, we isolate the impact of domain-specific fine-tuning. The model overcomes baseline overgeneralization (47.8% F1) to achieve saturated extraction accuracy on unseen data (i.e., 100% for the best model). Remarkably, it reaches this saturation on an 85% held-out test split using a mere 10% of the data for fine-tuning, demonstrating true robustness across heterogeneous literature. Ultimately, by open-sourcing our data and methods, this fine-tuning framework transitions chemical information retrieval from fragmented, rule-based heuristics to unified, concurrent extraction towards bridging the gap between experimental limitations and data-driven molecular design and modeling. Full article

Tuna peptides possess significant bioactivity but are limited by their persistent fishy odor. This study employed mild oxidation with medical-grade hydrogen peroxide (3% H₂O₂) to deodorize tuna peptides. The optimal parameters determined through single-factor and orthogonal experiments were 798 mmol/L H₂O₂, 35 °C, and 20 min. Under these conditions, the sensory score decreased markedly from 5 (very strong odor) to 2.48 (slight odor). Solid-phase microextraction and gas chromatography/mass spectrometry (SPME-GC/MS) analysis confirmed the complete removal of key odorants such as octanal and heptanal, along with a 44.8–54.7% reduction in other volatile compounds. Importantly, the treated peptides retained substantial antioxidant activity, with 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging rates of 91.5% and 78.3%, respectively. Successful incorporation of the deodorized peptides into a moisturizer demonstrated effective and lasting odor reduction. The proposed method offers an efficient, mild, and industrially viable strategy to expand the application of tuna peptides in functional cosmetics and foods. Full article

Copper(II) compounds exhibit interesting magnetic properties due to halide–halide, copper–halide, and intermolecular hydrogen bond interactions. In this study, seven new copper(II) bromide complexes were synthesised, six of which contain Dabco (1,4-diazabicyclo[2.2.2]octane) as a ligand. Single-crystal X-ray diffraction data were refined using both conventional spherical-atom models and a non-spherical-atom approach implemented in NoSpherA2. Magnetic properties were investigated by temperature-dependent magnetic susceptibility and field-dependent magnetisation measurements, analysed using a molecular field approximation. Crystallographic analysis shows that NoSpherA2 significantly improves the description of hydrogen atom positions, yielding C–H and N–H bond lengths closer to neutron diffraction values than conventional refinement. Magnetic measurements indicate that interactions between mononuclear copper(II) centres are determined primarily by the nature of intermolecular exchange pathways rather than copper–copper separations alone. Despite comparable Cu···Cu distances, complexes lacking N–H···Br hydrogen bonds exhibit only weak antiferromagnetic interactions, whereas stronger coupling, effective up to 150 K, is observed when such hydrogen bonds connect neighbouring complexes. These results highlight the importance of hydrogen-bond topology and three-dimensional connectivity in governing magnetic behaviour in mononuclear copper(II) systems. Full article