Search Results (1,052)

This study employs molecular dynamics simulations to investigate the condensation behavior of water molecules on hydrophilic/hydrophobic substrates under varying electric field strengths. It reveals the synergistic regulation effect between electric field strength and surface wettability from the perspectives of condensation rate and morphological evolution. The results indicate that the condensation rate on hydrophilic surfaces first increases and then decreases with increasing electric field strength; the condensation efficiency reaches its maximum at an electric field strength of 1.6 V/nm. Conversely, the condensation efficiency on hydrophobic surfaces shows a monotonically decreasing trend with increasing electric field strength; the presence of an electric field does not facilitate condensation on hydrophobic surfaces. The orientation of water molecule dipole moments is synergistically regulated by external electric fields, intermolecular interactions, and substrate–water interactions. The weaker the wettability, the more readily the electric field assumes a dominant role. Furthermore, the electric field induces parallel alignment of dipole moments along its direction, enhancing intermolecular attractions along the electric field axis (Z-axis). This also drives the reconfiguration of hydrogen-bond networks, ultimately leading to the aggregation of water molecules into clusters aligned with the electric field, thereby transforming the condensation morphology. Full article

The treatment of oily wastewater represents a significant environmental challenge, requiring efficient separation technologies and waste valorization. This study evaluated different types of coagulants (ferric chloride 38% m/m, aluminum polychloride 18% m/m, aluminum sulfate 8% m/m, and ferrous sulfate 6% m/m) and anionic polymers (from six suppliers) for treating poultry slaughterhouse effluent, aiming to optimize both clarification and oil recovery from the floated sludge. Bench-scale jar tests (G = 300 s⁻¹ and 30 s⁻¹) were followed by full-scale validation in a dissolved air flotation unit (100 m³ h⁻¹) at a poultry processing WWTP. Recovered oil was extracted by hot cooking (95 °C) and tridecanter centrifugation, and its quality (moisture, acidity, saponification index) was assessed. A techno-economic analysis, including simple/discounted payback, NPV, IRR, Monte Carlo simulation (10,000 iterations, Python), and deterministic sensitivity analysis, was performed. Ferric chloride (38% m/m) produced the best technical results: treated effluent turbidity < 30 NTU, oil yield of 360 L day⁻¹ with moisture < 2% at the tridecanter outlet, and consistent sludge dewaterability (moisture 55–65%). Oil moisture increased dramatically (to >30%) after storage due to condensate contamination from an inefficient exhaust system, a critical operational flaw that must be corrected. No statistically significant effect of polymer type on oil recovery was observed, although high variability (CV > 50%) was noted during PAC tests. The simple payback period for ferric chloride was 60.7 months (discounted: 64.1 months), with a positive median NPV (USD 7925) under a 12% p.a. discount rate. Sensitivity analysis showed that the investment is most sensitive to oil price: a 20% drop in oil price leads to a negative NPV (−USD 21,727). Despite this risk, the project provides environmental compliance and waste-to-value benefits. The study demonstrates that ferric chloride enables effective oil extraction from poultry wastewater, but proper exhaust design is essential to maintain oil quality. Future work should focus on standardized test durations (≥72 h) and automated monitoring to reduce variability. Full article

Decarbonizing air travel poses a major technological challenge, driven by the substantial power requirements of the drivetrain and the demanding weight and volume constraints of airborne systems. One promising avenue involves leveraging the high specific energy of hydrogen by designing compact, high-power fuel cell stacks to supply power for electric drivetrains. However, a key drawback of such propulsion architectures is the substantial heat generated within the fuel cells, which necessitates bulky and heavy thermal management systems to ensure safe and continuous operation. This study investigates a proposed air-based thermal management system, which operates by introducing pulsating heat pipes into the bipolar plates of a High-Temperature Polymer Electrolyte Membrane Fuel Cell (HT-PEM FC) stack. If proven to be feasible, heat pipe assisted air cooling may provide the benefit of reducing overall system complexity by decreasing the number of components in the thermal management system. To evaluate the thermal performance of the proposed system, a one-dimensional thermal model was initially developed in a previous study to describe the temperature distribution along the length of a heat pipe. Building upon this foundation, the present work extends the model by incorporating a two-dimensional Computational Fluid Dynamic (CFD) analysis to account for geometry-specific effects within the hexagonal design. Results indicate that the heat transfer from the hexagonal heat pipe geometry to the coolant air flow was marginally overestimated in previous analytical calculations. Revised heat transfer rates led to a shift in the predicted temperature distributions, resulting in the need for either increased external airflow, extended condenser sections, or reduced inlet temperatures to maintain target operating conditions. Although these adjustments may result in a slight increase in system mass and parasitic power consumption, the overall impact is limited, and the heat pipe-assisted air cooling approach remains theoretically feasible. Based on the results, design modifications are proposed and their impact on thermal performance is evaluated to address the challenges of heat rejection and temperature uniformity. A modification based on variation and optimization of PHP meander lengths was evaluated using the updated model and it significantly improved temperature homogeneity across the evaporator. Full article

Dry rooms used in battery and semiconductor research facilities require ultra-low dew-point environments, which demand significant thermal energy for desiccant rotor regeneration. In steam-regenerated systems, condensate discharged through steam traps partially evaporates due to pressure reduction, generating flash steam that is typically released into the atmosphere, resulting in substantial energy losses. This study investigates the generation and recovery potential of flash steam in dry room HVAC systems. Field measurements were conducted for 18 steam-regenerated desiccant air handling units installed in a medium-scale research facility (total floor area: 43,000 m²) in southern Gyeonggi Province, Korea. Boiler operation data—including feedwater flow rate, pressure, and operating time—were analyzed over a six-month period from March to August 2025. The results showed that the average flash steam generation rate was approximately 1.16 ton/h, corresponding to 8.56% of the average feedwater flow rate. Two recovery methods were evaluated: a steam jet thermocompressor (SJT) and an exhaust vapor condenser (EVC). The analysis revealed that the EVC system provides a more practical solution for medium-scale dry rooms because it does not require high-pressure primary steam. By recovering flash steam using three EVC units, an average heat recovery of 724 kW was achieved. The recovered heat can produce 86 °C hot water, which can be utilized as a driving heat source for an absorption chiller, generating approximately 507 kW of cooling capacity. This configuration partially offsets the cooling load of existing centrifugal chillers, thereby reducing electrical energy consumption. In addition, the proposed system eliminates atmospheric discharge of flash steam, mitigating the visible white plume phenomenon commonly observed in industrial facilities. The results demonstrate the technical feasibility of integrating flash steam recovery with absorption cooling to enhance energy efficiency in medium-scale dry room HVAC systems. Full article

This study evaluated the effects of sodium monensin or a blend containing condensed tannins and yeast products on intake, digestibility, performance, and methane emissions in lactating Holstein cows. Nine cows (three rumen-fistulated and six non-fistulated) were assigned to three 3 × 3 Latin squares. The treatments were: a control (CON), sodium monensin (MON; 12 mg/kg of dry matter [DM]), condensed Acacia tannins and Saccharomyces cerevisiae yeast blend (SUP; 2 g/kg of DM). The trial lasted 84 days, with three 28-day periods. Neutral detergent fiber (NDF) intake was higher in CON and SUP (p = 0.029). Milk yield, energy-corrected milk, and milk composition did not differ (p > 0.05). The total methane emissions were not affected by treatments (p > 0.05). Methane yield/Kg of DM intake (DMI), organic matter intake (OMI), and digestible OM tended to be lower in SUP (p = 0.091, p = 0.093, p = 0.086). SUP increased the DM, crude protein (CP), and NDF ingestion rates (p = 0.049, p = 0.028, p = 0.013) and decreased the CP rumen pool (p = 0.014). Rumen pH tended to be higher in SUP (p = 0.067). The potentially digestible NDF digestion rate decreased in MON (p = 0.007). Finally, SUP-treated animals showed a tendency to reduce their methane yield relative to DMI, OMI, and digestible OM. Further studies should investigate the long-term impacts of supplementation, rumen microbiome changes, and underlying mechanisms driving methane mitigation. Full article

Environmental fires pose a serious threat to energy security, ecosystems and public safety, whilst traditional halogenated flame retardants suffer from limitations such as high environmental residue risks and insufficient flame-retardant efficacy. In this study, sodium alginate (SA) was utilised as the matrix, with the incorporation of ammonium polyphosphate (APP) and phytic acid (PA), in conjunction with SiO₂-APTES surface modification, to prepare nitrogen–phosphorus synergistic bio-based flame-retardant gels. The present study systematically investigated the influence of the N/P molar ratio on the gelation kinetics, rheological behaviour, microstructure and flame-retardant performance of the gel. The study revealed a nitrogen–phosphorus coupled gas–solid two-phase synergistic flame-retardant mechanism. The results indicate that at an N/P ratio of 1/4, the gel forms a stable dual-network structure comprising ionic cross-links and Si–O–P covalent bonds. In the gas phase, the thermal decomposition of APP releases inert NH₃, which dilutes oxygen and quenches gas-phase radicals (·OH, ·H). In the condensed phase, the phosphate groups of PA-catalysed SA form Si–O–P covalent bonds with SiO₂ under the mediation of APTES, creating a dense, insulating char layer. In comparison with the control group (N/P = 0/0), the optimal gel sample (N/P = 1/4) demonstrated a 33% increase in shear stress, a 10% reduction in the peak heat release rate (HRR), a 75% decrease in total smoke production (TSP), and a 150% increase in char layer thickness after combustion, while maintaining adequate mechanical strength, thermal stability, and environmental friendliness. This work provides novel insights and strategies for the development of green, highly efficient flame-retardant materials for environmental fire prevention and control. Full article

The development of high-performance flame-retardant (FR) polypropylene (PP) with high mechanical integrity remains a challenge. Herein, we demonstrate a synergistic flame retardancy system for PP achieved via partial substitution of piperazine pyrophosphate (PAPP) with 1 wt.% magnesium borate whiskers (MBW) for improved flame retardancy, and thermal and mechanical properties. The optimized PP/24PAPP/1MBW exhibits exceptional FR performance, driven by the formation of a highly ordered, continuous phosphorus–boron hybrid char in the condensed phase. Cone calorimetry test results reveal an 80% reduction in peak heat release rate, a 54% reduction in total heat release, and a 33% reduction in total smoke production compared to neat PP, while the UL-94 test confirms a V-0 rating with complete suppression of flaming drips. Morphological study of the char residue using Raman spectroscopy and SEM attributes this performance to enhanced char graphitization and structural coherence enabled by boron-mediated cross-linking. More importantly, this transformative flame retardancy performance is achieved without severe compromise to mechanical properties, retaining over 89% of the original tensile strength. This work confirms the PAPP/MBW system as a highly efficient, low-additive approach to creating advanced fire-safe polymer composites for engineering applications. Full article

Water plays a critical role in residential consumption, accounting for a significant share of public water supply use. With increasing concerns over water scarcity and projections that a large portion of the global population will experience water stress by 2050, the need for effective water conservation strategies has become more urgent. This study evaluates the application and combined impact of water conservation measures in single-family homes. A deterministic modeling framework is developed to estimate household water consumption and conservation potential across four U.S. cities, namely, Houston, Phoenix, Las Vegas, and Des Moines, representing diverse climatic conditions. The analysis incorporates rainwater harvesting, HVAC condensate recovery, water-efficient fixtures, and greywater reuse systems. Scenario-based forecasting, including adoption rates of 1% and 5% of existing homes alongside new construction, is conducted over a six-year period using exponential smoothing techniques. Results indicate that the combined implementation of these measures can generate substantial aggregate water savings, with outcomes varying by climate and location. Greywater reuse and water-efficient fixtures consistently provide the largest contributions, while rainwater harvesting and condensate recovery depend more heavily on regional conditions. These findings highlight the importance of integrated and location-specific strategies and demonstrate the potential of decentralized, residential-level interventions to reduce demand on municipal water systems. Full article

Oxidative catalytic fractionation (OCF) under the lignin-first strategy has emerged as a critical technological approach for biomass refining. To address the inevitable carbohydrate degradation and lignin condensation in conventional OCF, this study designed a cobalt-doped layered double hydroxide oxide (Co-LDO) catalyst compatible with non-alkaline (without Brønsted bases) organic systems, which exhibits excellent performance in poplar biomass OCF. With a straightforward preparation process, the Co-LDO catalyst yields high-content oxidized lignin oligomers while efficiently retaining carbohydrates, providing feedstock rich in carbohydrates (cellulose and hemicellulose) for the subsequent production of bioenergy and biomass-based chemicals. Under optimized conditions screened via systematic reaction condition investigation and metal-doped LDO catalyst evaluation, the process achieved a 94.01 wt% delignification rate, with 72.19 wt% of lignin converted into lignin oligomer oil, supported by detailed product composition and structural characterization. Meanwhile, 74.14 wt% hemicellulose and 98.23 wt% cellulose were recovered in solid residues, with structurally intact hemicellulose retention being 2.3 times higher than in traditional OCF. Mass balance calculation confirmed a total poplar refining yield of 81.58 wt%. In summary, this Co-LDO-catalyzed OCF strategy provides a high-activity non-precious metal system, effectively suppressing lignin condensation while preserving high-yield carbohydrates, realizing the efficient full-component refining of poplar biomass. Full article

Epoxy resins (EP) are widely used in aerospace, electronics, and coatings due to their excellent mechanical and thermal properties. However, their inherent flammability and brittleness limit high-end applications. In this work, a novel reactive flame retardant epoxy monomer (EP-DVGA) containing DOPO and triazole units was designed and synthesized via a molecular engineering strategy. The chemical structure was confirmed by FTIR and NMR. A series of modified epoxy thermosets were prepared by co-curing EP-DVGA with bisphenol A epoxy resin (E51) using DDM as curing agent. The results showed that EP-DVGA significantly enhanced flame retardancy: At 16.31 wt% loading, the limiting oxygen index increased from 25.9% to 34.3% with UL-94 V-0 rating, and cone calorimetry revealed 73.2% and 69.2% reductions in peak heat release rate and total heat release, respectively. Mechanistic studies demonstrated a dual flame retardant effect involving phosphorus radical quenching in the gas phase and formation of a dense graphitized char layer in the condensed phase. Remarkably, EP-DVGA also improved mechanical properties—impact strength increased by 47% and tensile strength by 33.1% at optimal loadings—attributed to energy dissipation through reversible hydrogen bonding and π–π interactions. This molecular design successfully overcomes the traditional trade-off between flame retardancy and mechanical performance, offering a promising strategy for developing high-performance intrinsically flame retardant epoxy materials. Full article

This study experimentally investigates the thermal performance of wraparound loop heat pipes (WLHP) using R134a as the working fluid and copper tubing with an outer diameter of 8.5 mm. A dedicated experimental apparatus was developed to evaluate thermal resistance under varying heat loads (200–500 W), inclination angles (15° and 30°), and coolant temperatures (5–15 °C) at a constant coolant flow rate of 3.2 L/min. Key performance metrics, including evaporator wall temperature and overall thermal resistance, were analyzed to identify optimal operating conditions. The results reveal that increasing the heat load significantly reduces thermal resistance, reaching a minimum of 0.056 °C/W at 500 W. An inclination angle of 30° improved heat transfer, lowering the evaporator temperature by approximately 5 °C compared to 15°. Moreover, lower coolant temperatures enhanced the temperature gradient between the evaporator and condenser, further improving heat transfer. Principal component analysis (PCA) was employed for dimensionality reduction and identification of the dominant thermal variables affecting system performance. Based on the experimental dataset, a regression model was developed to predict thermal resistance, achieving a coefficient of determination of R² = 0.96. These findings confirm the WLHP’s potential as an efficient and reliable passive thermal management system for medium- to high-power applications in tropical and industrial environments. Full article

Italy and the surrounding seas are recognised as one of the European hotspots for tornadoes and waterspouts. In recent years, the town of Rosignano Solvay (on the Northern Tyrrhenian coast) experienced repeated waterspouts affecting the same areas, raising local concern about the possible influence of heated wastewater discharged into the sea by a nearby industrial site. We reconstruct the mesoscale meteorological conditions of four intense waterspouts near Rosignano Solvay using a limited-area weather model at a high-to-very-high resolution (inner domain grid spacing of 500 m; sensitivity tests at 100 m). At the reported event times, the intensity of key mesoscale precursors (low-level wind shear, 1 km storm-relative helicity, maximum updraft intensity, and lifting condensation level) is consistent with the values typically associated with EF1 (or stronger) tornadoes and waterspouts. The model systematically predicts the peak of instability indices 2–3 h earlier than the reported event times. For one case study, we conduct two sea surface temperature sensitivity experiments to assess the potential atmospheric impact of heated wastewater discharge (temperature increases of +1.5 K and +5 K over a 10 km² area). The resulting changes in instability indices are marginal, with differences of at most 3% relative to the control run. A simple mass-balance estimate for the modified sea patch suggests that, given the reported discharge rates, a plausible impact of the warm water released from the industrial site could lead to an increase in the local sea surface temperature of approximately +0.7 °C over two months. We conclude that synoptic and mesoscale conditions primarily govern waterspout initiation in this region, while the direct effect of the small warm coastal plume from the industrial discharge appears to be minor. Full article

Natural gas streams extracted from production wells often contain undesirable components such as water vapor, gas condensate, and solid particulates. These impurities reduce fuel quality and damage downstream equipment through corrosion, fouling, and foaming. This study presents the development and field-scale evaluation of a high-performance gas–liquid separator designed for the deep decontamination of natural gas. The proposed separator incorporates 30 suspended baffles arranged in three rows and an anti-foaming mesh to enhance phase separation and prevent liquid re-entrainment. Field experiments were conducted at the Somontepa gas field in Uzbekistan. Compared to the baseline industrial unit, the upgraded separator reduced gas condensate from 16.58 g/m³ to 0.725 g/m³, water from 4.84 g/m³ to 0.10 g/m³, and solid impurities from 1.20 g/m³ to 0.0058 g/m³. The foam height was lowered from 96.4 mm to 10.2 mm, and the average bubble diameter was reduced by over 60%. The design maintained low pressure drops and demonstrated stable operation under varying flow rates. Fractional analysis confirmed the quality of a recovered condensate suitable for downstream utilization. The proposed configuration offers substantial improvements in gas purification performance and economic efficiency. These results support the application of this separator design for high-contaminant natural gas streams in industrial gas processing facilities. Full article

Gas condensate banking can significantly reduce near-well gas productivity by as much as ~60% in tight gas reservoirs. Existing treatment techniques are resource demanding and could alter the reservoir structure permanently. This study investigates the effectiveness of enhanced electrokinetic oil recovery (EK-EOR) as a low-impact alternative for treating condensate banks. Using compositional reservoir simulation (CMG GEM), the influence of key reservoir and operational parameters—porosity, permeability, producer well location (i, j), injection rate, and injection pressure—on cumulative gas production (CGP) was examined. A Box–Behnken design of experiments was employed to generate 62 simulation runs, and a proxy model was developed to approximate full-field responses. Statistical validation showed strong model fidelity (R² = 0.99, AAPE = 2.2%). The proxy was then optimized using a genetic algorithm (GA) to identify conditions that maximize gas recovery. Results indicate that lower injection rates and lower injection pressures maximize CGP through enhanced electro-osmotic flow and reduced water blocking, achieving a peak cumulative gas of 4.06 × 10⁸ ft³. A secondary optimum at high injection pressure could be attributed to re-pressurization and partial re-vaporization of condensate near the wellbore. Reservoir quality also exerted a strong control: higher permeability and moderate porosity favoured gas yield, while optimal producer placement near the reservoir boundary increased drainage efficiency. This study demonstrates a systematic optimization framework combining design of experiments, proxy modelling, and evolutionary algorithms to evaluate EK-EOR performance. Full article

This study explores the viability of condensate petroleum, an ultra-light hydrocarbon derived from natural gas production, as an alternative diesel engine fuel. The researchers tested six different fuel blends, increasing the condensate volume by 10% increments, in a compression ignition engine under three distinct load conditions (25%, 50%, and 75%) to evaluate both combustion characteristics and emission performance. The results demonstrate that condensate blends significantly enhance key combustion parameters. The heat release rate, in-cylinder pressure, and in-cylinder temperature all increased, with the highest heat release rate improvement of 35.6% observed at a 75% load using a 60% condensate petroleum blend. However, increasing the condensate ratio also extended ignition delay times and raised the ringing intensity, which peaked with a 34.7% increase at a 25% load. Brake thermal efficiency improved at lower and medium loads—achieving a maximum 11.2% increase with the 50% condensate petroleum blend at 50% load—but decreased when the engine reached 75% load. In terms of environmental impact, the condensate blends proved largely beneficial. Carbon monoxide emissions dropped by 57.9% (at 75% load, 60% condensate petroleum), smoke opacity decreased by 72.6% (at 25% load, 40% condensate petroleum), and hydrocarbons fell by 34.4% (at 50% load, 60% condensate petroleum). The primary drawback was that nitrogen oxide emissions worsened, increasing by 20.4% at 75% load with the 50% condensate petroleum blend. Overall, the study concludes that the effects of condensate petroleum are highly acceptable, making it a promising alternative fuel and additive for diesel engines. Full article