Search Results (2,121)

Efficient and sustainable extraction of bioactive benzopyrans from Hypericum polyanthemum Klotzsch ex Reichardt (Hypericaceae) remains underexplored, despite their potential applications. The current study aimed to optimize this process by integrating computational simulation and experimental extraction with suitable solvents. The COSMO-RS model was employed to screen deep eutectic solvents (DESs), indicating lactic acid/glycine/water 3:1:3 (DES 1) as a highly promising candidate based on activity coefficients at infinite dilution for target benzopyrans (HP1, HP2, HP3). Ultrasound-assisted extraction (UAE) was then conducted using the proposed DES as well as hexane, and the extracts were analyzed via high-performance liquid chromatography (HPLC) and spectrophotometry for total phenolic content (TPC). The results for DES 1 showed yields for benzopyrans HP1 (1.43 ± 0.09 mg/g plant) and HP2 (0.55 ± 0.04 mg/g plant) close to those obtained in the hexane extract (1.65 and 0.78 mg/g plant, respectively), corroborating the use of COSMO-RS for solvent screening. Kinetic analysis using an adapted Crank diffusion model successfully described the mass transfer process for DES 1 (R² > 0.98, mean average percent error < 9%), indicating diffusion control and allowing estimation of effective diffusion coefficients. This work confirms COSMO-RS as a valuable tool for solvent selection and demonstrates that UAE with the identified DES provides an efficient, greener approach for extracting valuable benzopyrans, offering a foundation for further process optimization. Full article

Under the context of the dual-carbon policy, reducing energy consumption and emissions in automobiles has garnered significant attention, with automotive lightweighting being particularly important. This paper focuses on the lightweight design of automotive subframes, aiming to minimize weight while meeting performance requirements. Research has revealed that the original subframe allows further room for lightweighting and performance optimization. A topology optimization model was established using the Solid Isotropic Material with Penalization (SIMP) method and solved using the Method of Moving Asymptotes (MMA) algorithm. Integration of the SIMP method was achieved on the Abaqus-Matlab (2022x) platform via Python (3.11.0) and Matlab (R2022a) coding, forming an effective optimization framework. The optimization results provided clear load transfer paths, offering a theoretical basis for geometric model conversion. The subframe model was subsequently reconstructed in CATIA. Material redundancy was identified in the reconstructed subframe model, prompting secondary optimization. Multi-objective size optimization was conducted in OptiStruct, reducing the subframe’s mass from 33.73 kg to 17.84 kg, achieving a 47.1% weight reduction. Static stiffness and modal analyses performed in HyperMesh confirmed that results met all relevant standards. Modal testing revealed a minimal deviation of only −2.7% from the simulation results, validating the feasibility and reliability of the optimized design. This research demonstrates that combining topology optimization with size optimization can significantly reduce weight and enhance subframe performance, providing valuable support for future automotive component design. Full article

To achieve energy transition, hydrogen and carboxylic acids have attracted much attention due to their cleanliness and renewability. Anaerobic fermentation technology is an effective combination of waste biomass resource utilization and renewable energy development. Therefore, the utilization of anaerobic fermentation technology is expected to achieve efficient co-production of hydrogen and carboxylic acids. However, this process is fundamentally affected by gas–liquid mass transfer kinetics, bubble behaviors, and system partial pressure. Moreover, the related studies are few and unfocused, and no systematic research has been developed yet. This review systematically summarizes and discusses the basic mathematical models used for gas–liquid mass transfer kinetics, the relationship between gas solubility and mass transfer, and the liquid-phase product composition. The review analyzes the roles of the headspace gas composition and partial pressure of the reaction system in regulating co-production. Additionally, we discuss strategies to optimize the metabolic pathways by modulating the gas composition and partial pressure. Finally, the feasibility of and prospects for the realization of hydrogen and carboxylic acid co-production in anaerobic fermentation systems are outlined. By exploring information related to gas mass transfer and system pressure, this review will surely provide an important reference for promoting cleaner production of sustainable energy. Full article

One of the hottest topics in current research is the creation of scaffolds for bone tissue restoration that are both biocompatible and tissue inducible. The aim of this work is to develop a numerical model to study the effects of temperature, velocity, and scaffold structure on flow and biomechanical properties, as well as to optimize design parameters to improve tissue engineering outcomes. The results show that the fluid transport properties of cylindrical unit cell architectures are superior. For effective mass transfer, pore diameters > 4 mm and porosity > 60% are ideal design parameters. With important clinical and financial implications, these discoveries offer theoretical direction and economical methods for developing bone tissue engineering. Full article

The precise forecasting of mesoscale eddy trajectories holds significant importance for understanding their mechanisms in driving global oceanic mass and heat transport. However, mesoscale eddies are influenced by numerous stochastic and uncertain factors, leading to substantial fluctuations in their attribute variables. Additionally, the trajectories of eddies are related to historical trends and interact with surrounding eddies. These render the accurate forecasting of mesoscale eddy trajectories a formidable challenge. This study proposes a novel dynamic forecasting framework for eddies’ trajectories, termed EddyGnet, a dual graph neural network framework that synergistically models the complex multivariable association and the spatiotemporal eddy association. In this framework, the dynamic association among eddy attribute variables is first explored by a multivariable association graph (MAG) learning module. Subsequently, the spatial and temporal association among eddies are concurrently analyzed using a spatiotemporal eddy association graph (STEAG) learning module. Finally, a decayed volatility loss function is designed to properly handle the complex and variable data features and improve the forecasting performance. The experimental results on the eddy dataset verify the effectiveness of our proposed EddyGnet, demonstrating superior predictive accuracy and stability compared with existing classical methods. The findings advance the mechanistic understanding of eddy dynamics and provide a transferable paradigm for geoscientific spatiotemporal modeling. Full article

Wastewater treatment plants (WWTPs) face increasing pressure to handle higher volumes of water due to climate change causing storm surges, which current infrastructure cannot handle. Aerobic granular sludge (AGS) is a promising alternative to activated sludge systems due to their improved settleability property, lowering the land footprint and improving efficiency. This research investigates the optimisation of a lab-scale sequencing batch reactor (SBR) into a continuous flow reactor through mathematical modelling, sensitivity analysis, and a computational fluid dynamic model. This is all applied for the future goal of scaling up the model designed to a full-scale continuous flow reactor. The mathematical model developed analyses microbial kinetics, COD degradation, and mixing flows using Reynolds and Froude numbers. To perform a sensitivity analysis, a Python code was developed to investigate the stability when influent concentrations and flow rates vary. Finally, CFD simulations on ANSYS Fluent evaluated the mixing within the reactor. An 82% COD removal efficiency was derived from the model and validated against the SBR data and other configurations. The sensitivity analysis highlighted the reactor’s inefficiency in handling high-concentration influents and fast flow rates. CFD simulations revealed good mixing within the reactor; however, they did show issues where biomass washout would be highly likely if applied in continuous flow operation. All of these results were taken under deep consideration to provide a new reactor configuration to be studied that may resolve all these downfalls. Full article

To explore the influence of mine roof on the damage and failure of sandstone surrounding rock under different pressure rates, mechanical experiments with different strain rates were carried out on sandstone rock samples. The strength, deformation, failure, energy and damage characteristics of rock samples with different strain rates were also discussed. The research results show that with the increases in the strain rate, peak stress, and elastic modulus show a monotonically increasing trend, while the peak strain decreases in the reverse direction. At a low strain rate, the proportion of the mass fraction of complete rock blocks in the rock sample is relatively high, and the shape integrity is good, while rock samples with a high strain rate retain more small-sized fragmented rock blocks. This indicates that under high-rate loading, the bifurcation phenomenon of secondary cracks is obvious. The rock samples undergo a failure form dominated by small-sized fragments, with severe damage to the rock samples and significant fractal characteristics of the fragments. At the initial stage of loading, the primary fractures close, and the rock samples mainly dissipate energy in the forms of frictional slip and mineral fragmentation. In the middle stage of loading, the residual fractures are compacted, and the dissipative strain energy keeps increasing continuously. In the later stage of loading, secondary cracks accelerate their expansion, and elastic strain energy is released sharply, eventually leading to brittle failure of the rock sample. Under a low strain rate, secondary cracks slowly expand along the clay–quartz interface and cause intergranular failure of the rock sample. However, a high strain rate inhibits the stress relaxation of the clay, forces the energy to transfer to the quartz crystal, promotes the penetration of secondary cracks through the quartz crystal, and triggers transgranular failure. A constitutive model based on energy damage was further constructed, which can accurately characterize the nonlinear hardening characteristics and strength-deformation laws of rock samples with different strain rates. The evolution process of its energy damage can be divided into the unchanged stage, the slow growth stage, and the accelerated growth stage. The characteristics of this stage reveal the sudden change mechanism from the dissipation of elastic strain energy of rock samples to the unstable propagation of secondary cracks, clarify the cumulative influence of strain rate on damage, and provide a theoretical basis for the dynamic assessment of surrounding rock damage and disaster early warning when the mine roof comes under pressure. Full article

The spray evaporation process in the boiler desuperheater involves complex droplet behaviors and fluid–thermal coupling, and its temperature distribution characteristics greatly affect the performance and safety of industrial processes. To better understand the process characteristics and develop the optimal desuperheater design, computational fluid dynamics (CFDs) was applied to numerically investigate the flow and thermal characteristics. The Eulerian–Lagrangian approach was used to describe the two-phase flow characteristics. Both primary and secondary droplet breakup, the coupling effect of gas–liquid and stochastic collision and coalescence of droplets were considered in the model. The plain-orifice atomizer model was applied to simulate the atomization process. The numerical model was validated with the plant data. The spray tube structure was found to greatly affect the flow pattern, resulting in the uneven velocity distribution, significant temperature difference, and local reverse flow downstream of the orifices. The velocity and temperature distributions tend to be more uniform due to the complete evaporation and turbulent mixing. Smaller orifices are beneficial for generating smaller-sized droplets, thereby promoting the mass and heat transfer between the steam and droplets. Under the same operating conditions, the desuperheating range of cases with 21, 15, and 9 orifices is 33.7 K, 32.0 K, and 29.8 K, respectively, indicating that the desuperheater with more orifices (i.e., with smaller orifices) shows better desuperheating ability. Additionally, a venturi-type desuperheater was numerically studied and compared with the straight liner case. By contrast, discernible differences in velocity and temperature distribution characteristics can be observed in the venturi case. The desuperheating range of the venturi and straight liner cases is 38.1 K and 35.4 K, respectively. The velocity acceleration through the venturi throat facilitates the droplet breakup and improves mixing, thereby achieving better desuperheating ability and temperature uniformity. Based on the investigation of the spray evaporation process, the complex droplet behaviors and fluid–thermal coupling characteristics in an industrial boiler desuperheater under high temperature and high pressure can be better understood, and effective guidance for the process and design optimizations can be provided. Full article

The Wyrtki Jet (WJ), a pivotal surface circulation system in the equatorial Indian Ocean, exerts significant regulatory control over regional climate dynamics through its intense eastward transport characteristics, which modulate water mass exchange, thermohaline balance, and cross-basin energy transfer. To address the scarcity of in situ observational data, this study developed a satellite remote sensing-driven multi-parameter coupled model and reconstructed the WJ’s seasonal variations using the XGBoost machine learning algorithm. The results revealed that wind stress components, sea surface temperature, and wind stress curl serve as the primary drivers of its seasonal dynamics. The XGBoost model demonstrated superior performance in reconstructing WJ’s seasonal variations, achieving coefficients of determination (R²) exceeding 0.97 across all seasons and maintaining root mean square errors (RMSE) below 0.2 m/s across all seasons. The reconstructed currents exhibited strong consistency with the Ocean Surface Current Analysis Real-time (OSCAR) dataset, showing errors below 0.05 m/s in spring and autumn and under 0.1 m/s in summer and winter. The proposed multi-feature integrated modeling framework delivers a high spatiotemporal resolution analytical tool for tropical Indian Ocean circulation dynamics research, while simultaneously establishing critical data infrastructure to decode monsoon current coupling mechanisms, advancing early warning systems for extreme climatic events, and optimizing regional marine resource governance. Full article

The oil and gas industry is subject to significant fire hazards due to the flammability of hydrocarbons and the extreme conditions of operational facilities. Intumescent coatings (ICs) serve as a crucial passive fire protection strategy, forming an insulating char layer when exposed to heat, thereby reducing heat transfer and delaying structural failure. This review article provides an overview of recent developments in the effectiveness of ICs in mitigating fire risks, enhancing structural resilience, and reducing environmental impacts within the oil and gas industry. The literature surveyed shows that analytical techniques, such as thermogravimetric analysis, scanning electron microscopy, and large-scale fire testing, have been used to evaluate the thermal insulation performances of the coatings. The results indicate significant temperature reductions on protected steel surfaces that extend critical failure times under hydrocarbon fire conditions. Recent advancements in nano-enhanced and bio-derived ICs have also improved thermal stability and mechanical durability. Furthermore, numerical modeling based on heat transfer, mass conservation, and kinetic equations aids in optimizing formulations for real-world applications. Nevertheless, challenges remain in terms of standardizing modeling frameworks and enhancing the environmental sustainability of ICs. This review highlights the progress made and the opportunities for continuous advances and innovation in IC technologies to meet the ever-evolving challenges and complexities in oil and gas industry operations. Consequently, the need to enhance fire protection by utilizing a combination of tools improves predictive modeling and supports regulatory compliance in high-risk industrial environments. Full article

This study describes both experimental and numerical investigations into the heat and mass transfer processes governing the vacuum freeze drying of camel milk, with a specific focus on improving the energy efficiency. A three-dimensional model was developed and solved using the finite element method to simulate temperature evolution and sublimation interface progression during drying. The numerical model was validated against experimental data, achieving strong agreement, with an $R^2$ value of 0.94. A detailed parametric analysis examined the effects of the shelf temperature, sample thickness, and chamber pressure on the drying kinetics and energy input. The results indicate that optimising these parameters can significantly reduce the energy consumption and processing time while maintaining product quality. Notably, reducing the sample thickness to 4 mm shortened the drying time by up to 40% and reduced the specific energy consumption (SEC) from 358 to 149 kWh/kg. These findings offer valuable insights for the design of more energy-efficient freeze drying systems, with implications for sustainable milk powder production and industrial-scale process optimisation. Full article

Permeate Gap Membrane Distillation (PGMD) is an emerging desalination technology that offers a promising alternative for freshwater production, particularly in energy-efficient and sustainable applications. This review provides a comprehensive analysis of PGMD, covering its fundamental principles, heat and mass transfer mechanisms, and key challenges such as temperature and concentration polarization. Various optimisation strategies, including Response Surface Morphology (RSM), Differential Evolution techniques, and Computational Fluid Dynamics (CFD) modelling, are explored to enhance PGMD performance. The study further discusses the latest advancements in system design, highlighting optimal configurations and the integration of PGMD with renewable energy sources. Factors influencing PGMD performance, such as operational parameters (flow rates, temperature, and feed concentration) and physical parameters (gap width, membrane properties, and cooling plate conductivity), are systematically analysed. Additionally, the techno-economic feasibility of PGMD for large-scale freshwater production is evaluated, with a focus on cost reduction strategies, energy efficiency, and hybrid system innovations. Finally, this review outlines the current limitations and future research directions for PGMD, emphasising novel system modifications, improved heat recovery techniques, and potential industrial applications. By consolidating recent advancements and identifying key challenges, this paper aims to guide future research and facilitate the broader adoption of PGMD in sustainable desalination and water purification processes. Full article

According to the literature, Schinus molle (SM) is an important source of bioactive phytochemicals, but the phytochemical content and composition of this species, which grows in high Andean geographic zones such as Tarma (Peru), is not known. In an effort to fill this gap, our work investigated the supercritical carbon dioxide extraction of SM leaves at three temperature levels (35, 45, and 55 °C) and three pressure levels (150, 250, and 350 bar). The results revealed the highest yield of extract at 150 bar, 45 °C, and 3.28 g CO₂/min. Under these conditions, the overall extraction curves (OEC) were modeled using the Spline, logistic, and Esquível models, allowing the generation of mass transfer parameters for SFE at the optimized conditions, resulting in a similar correlation with experimental data. Twenty-six compounds were identified in the SFE extract of SM leaves. The most abundant compound classes were sesquiterpenoids (57.17%), sesquiterpenes (24.50%), and triterpenoids (10.48%); of each class, the most abundant compounds were shyobunol (33.60%), bicyclogermacrene (12.68%), and lupeone (6.58%), respectively. The compounds detected possess bioactive properties that support further studies on the application of SFE extracts of SM as a functional ingredient in commercial products. Full article

This work investigates the potential industrial applications of two sodium bentonite samples (white and yellow), obtained from raw Ca-rich bentonite from Maputo Province in Southern Mozambique. Bentonite bio-organoclays were successfully developed from two Mozambican montmorillonite clays through the intercalation of protonated dimer fatty acid-based polyamide chains using a solution casting method. X-ray diffraction (XRD) analysis confirmed polymer intercalation, with the basal spacing (d₀₀₁) increasing from approximately 1.5 nm to 1.7 nm as the polymer concentration varied between 2.5 and 7.5 wt.%. However, the extent of intercalation was limited at this stage, suggesting that polymer concentration alone had a minimal effect, likely due to the formation of agglomerates. In a subsequent optimization phase, the influence of temperature (30–90 °C), stirring speed (1000–2000 rpm), and contact time (30–90 min) was evaluated while maintaining a constant polymer concentration. These parameters significantly enhanced intercalation, achieving d001 values up to 4 nm. Statistical Design of Experiments and Response Surface Methodology revealed that temperature and stirring speed exerted a stronger influence on d001 expansion than contact time. Optimal intercalation occurred at 90 °C, 1500 rpm, and 60 min. The predictive models demonstrated high accuracy, with R² values of 0.9861 for white bentonite (WB) and 0.9823 for yellow bentonite (YB). From statistical modeling, several key observations emerged. Higher stirring speeds promoted intercalation by enhancing mass transfer and dispersion; increased agitation disrupted stagnant layers surrounding the clay particles, facilitating deeper penetration of the polymer chains into the interlayer galleries and preventing particle settling. Furthermore, the ANOVA results showed that all individual and interaction effects of the factors investigated had a significant influence on the d₀₀₁ spacing for both WB and YB clays. Each factor exhibited a positive effect on the degree of intercalation. Full article

We combine corrected Gaia DR3 astrometry with non-conservative MESA modelling to retrace the evolution of the FS-CMa binary MWC 728. The revised parallax sets the distance at $d=1.2\pm 0.1$ kpc, leading—after Monte-Carlo error propagation—to luminosities of $log{(L/L_{\odot })}_{\mathrm{acc}}=2.6\pm 0.1$ and $log{(L/L_{\odot })}_{\mathrm{don}}=1.5\pm 0.1$, corresponding to the accretor and donor, respectively. A fiducial binary track that starts with $M_{\mathrm{don}}=3.6\pm 0.1M_{\odot }$, $M_{\mathrm{acc}}=1.8\pm 0.1M_{\odot }$, and $P_0=21.0\pm 0.2$ d reproduces the observations provided the Roche-lobe overflow, which is moderately non-conservative: only $39\%$ of the transferred mass is retained by the accretor, while the remainder leaves the system via (i) a fast isotropic wind from the donor ($\alpha =0.01$), (ii) isotropic re-emission near the accretor ($\beta =0.45$), and (iii) outflow into a circumbinary torus ($\delta =0.15$, lever arm $\gamma =1.3$). These channels remove sufficient angular momentum to expand the orbit to the observed $P_{\mathrm{obs}}=27.5\pm 0.1$ d while sustaining the dusty circumbinary outflow. At $t\simeq 223$ Myr, the model matches every current observable: $M_{\mathrm{don}}=1.30\pm 0.05M_{\odot }$, $M_{\mathrm{acc}}=2.67\pm 0.05M_{\odot }$, mass ratio $q=2.0\pm 0.1$, and an ongoing transfer rate of $\dot{M}\simeq (1\pm 0.3)\times {10}^{-6}{M}_{\odot }{\mathrm{yr}}^{-1}$. MWC 728 thus serves as a benchmark intermediate-mass binary for testing how non-conservative outflows regulate angular-momentum loss and orbital growth. Full article